Phase 1 clinical investigation of 4'-(9-acridinylamino)methanesulfon-m-anisidide (NSC 249992), a new acridine derivative. The compound 4'-(9-acridinylamino)methanesulfon-m-anisidide is a new derivative that was evaluated in a Phase 1 clinical trial. The schedule of drug administration consisted of daily i.v. injection for 3 consecutive days, repeated at 3-week intervals. Twenty-six patients received a total of 63 courses of 4'-(9-acridinylamino)methanesulfon-m-anisidide in a dose range from 4 to 50 mg/sq m/day. Hematopoietic toxicity was dose limiting, but it was of short duration and rapidly reversible. Mild nausea and vomiting were observed in 16% of the courses, and a mild degree of phlebitis was observed in 10% of the courses. Responses were observed in two patients with adenocarcinoma of the lung and one each of melanoma and acute myeloblastic leukemia. Phase 2 studies of 4'-(9-acridinylamino)methanesulfon-m-anisidide are planned at a starting dose of 40 mg/sq m/day for 3 days in good-risk patients and at 25 to 30 mg/sq m/day for 3 days in poor-risk patients. Course of treatment would be repeated at 21-day intervals.


Metabolism of proline in a human leukemic lymphoblastoid cell line. Amino acid analysis of the culture medium was carried out in a human leukemic lymphoblastoid cell line (REH) established from the lymphoblasts of a patient with acute lymphoid leukemia. The results are compared with those of a reference cell line (LHN13) established from normal human lymphocytes. The most striking difference between these two cell lines concerns proline. In LHN13 the concentration of this amino acid in the culture medium increases by 40 microgram/ml/10(6) cells during a 72-hr incubation. In REH there is a decrease under the same culture conditions. In both cell lines proline is derived from glutamic acid and from arginine, as found with the use of 14C-labeled precursors. Synthesis of proline in the REH line represents approximately 26% of the value measured in LHN13 when the precursor is glutamic acid and 15% when the precursor is arginine. The radioisotopic assay for delta1-pyrroline-5-carboxylate reductase showed that there is a deficiency of this enzyme in the REH cells. The defect in proline synthesis of REH was found at the establishment of this line and constitutes a metabolic marker that has persisted for more than 2 years.


Resistant level of houseflies to seven kinds of synthetic insecticides and effect of synergists to the Malathion resistant strain in Singapore. The resistant level of the houseflies to the seven kinds of insecticides, Malathion, Sumithion, Baytex, Diazinon, DDVP, DDT and Chrysron, was examined on the 3 strains collected in Singapore. It was found that most housefly colonies in Singapore showed a higher susceptibility to those insecticides than that of the Takatsuki strain of Japan, especially to DDT. However, the resistant level to Malathion was remarkably higher than that of the Takatsuki strain. The synergists, piperonyl butoxide, Safroxane and S-421, mixed with Malathion were effective for lowering the resistant level of the Malathion-resistant strain.


Computed tomography of the head: clinical experience of the first 3000 scans with EMI scanner. Computer tomography (CT) findings obtained from the first 3,000 scans on 2,031 patients were analyzed and discussions were made on various kinds of neurological diseases, especially from the neurosurgical point of view. CT showed an excellent resolution for three-dimensional morphological pattern of intracranial lesion with a high percentage of diagnostic accuracy as reported from other institutes, resulting in making much earlier morphological diagnosis of intracranial lesion possible than any other examination. Scan methods consisted of plain CT, contrast enhanced CT, and metrizamide CT cisternography. Sequential delayed enhanced CT offered more useful information for high diagnostic accuracy, particularly for nature of brain tumor. Metrizamide CT cisternography was performed for the evaluation of cerebrospinal fluid dynamics and diagnosis of skull base tumors. CT is a new, epoch-making and non-invasive diagnostic approach in neuroradiology and contributes to obtain the better achievement of neurosurgical results.


Physiological recalcification of carious dentin. In order to confirm the ability of physiological recalcification of the human carious dentin, the first layer of carious dentin was removed from the symmetric cavities of bilateral pairs of human teeth, disclosing it by 0.5% basic fuchsin-propylene glycol solution staining. One of the pair teeth was immediately extracted and the other was left in the mouth after filling the cavity with polycarboxylate cement. The Ca content and hardness of the remaining second layer immediately and three months after the operation were compared by an electron probe microanalyzer and microhardness tester. They increased markedly after three months returning to the normal level from inside, proving physiological recalcification. A similar experiment was performed by using bilateral pairs of dog teeth with cavities having artificially decalcified dentin floor. After removing the fuchsin-stainable first layer, one of the pair was immediately extracted and the other was left in the mouth for three months after exposing or filling the cavity with various cements. As the Ca content was compared, a marked recalcification of the second layer of softened dentin was observed after three months returning to the normal level from the inside. The effect of different cavity treatment was slight.


Neisseria in early stage of dental plaque. Neisseria in the early stage of dental plaque was studied. Two hundred seventeen strains of Neisseria were isolated from the 12-hour plaque of 9 subjects by using lactose-agar. The isolated strains were divided into 6 major groups with biological characteristics. One hundred twenty-one strains (56%) produced glycogen-like polysaccharide from sucrose. They were divided into 3 groups. Groups 1 and 2 were identified as N. mucosa and N. sicca, respectively. There were 106 strains of N. sica, being the most predominant of the species. The number of strains not producing polysaccharide was 96 (44%). Groups 4 and 5 were Branhamella and N. subflava. The absorption spectra of the ethanol extracts of the pigment in each group were similar and this result supported propriety of the classification by biological characteristics. The adhesiveness of Neisseria to the glass plate was examined. Approximately one-half of N. sica showed an adhesion capacity.


[Abrasion measurements in vivo in occlusal composite and amalgam fillings]. A new method for quantitative measurement of occlusal wear on restorations is described. In a clinical evaluation with four different composites and an amalgam the method proved to be simple in execution and very exact. Statistical analysis after 7 months has shown significant differences in wear resistance of the different materials. The nature of the resulting wear was electron optically examined. Typical structural surface characteristics were observed for each of the different materials. More recently developed composities utilizing extremly small filler particles (Aerosil) seem to be comparable to amalgam in wear resistance.


[The usefulness of the mandibular kinesiograph (MKG)]. The Jankelson mandibular kinesigraph is intended to reproduce the movements of the mandible electronically. Analyses of the measurements and clinical studies of linearity, reproducibility, and susceptibility to the electromagnetic fields showed that quantitative and qualitative evaluations of the recordings are impossible. The device therefore appears to us to be unsuitable for the clinical diagnosis of abnormal movements of the mandible and disturbances in occlusion.


[Strength and elasticity of metals].

[Strength and elasticity of metals]. The bending test can be used to ascertain the suitability of various metals for use in dental prostheses, particularly as material for retaining elements. The effects of prior stress (i.e., bending) or the dependence of the strength characteristics on the production can be seen particularly following stress produced by permanent swelling. A comparison of the various test results showed that the value of the technical limits of elasticity (0.01%) alone should be used for the theoretical computations for clips used as retaining elements. Statements concerning the suitability of a particular metal under endurance stress can only be made in this way. The homogeneity of cast parts should be established by determining the raw density.


[Closure of extensive oroantal perforations, caused by extraction, by means of modified gingival cheek flaps]. The reliable Rehrmann method of pedicaled buccal flaps taken from the gums and cheeks accompanied by slitting of the periosteum does not provide sufficiently long flaps for the wide junction betueen the oral cavity and the maxillary sinus which extends toward the palate. A sliding flap is recommended in such cases. This flap is formed by a triangle-shaped excision combined with cranial and caudal slitting of the periosteum. This procedure can also be used for simultaneous operations on the maxillary sinus after the bony defect has been closed with the method of bony coverage developed by the author.


[The SI unit system].

[The SI unit system]. The German "Law for Units of Measure" have restricted the number of units of measure acceptable for business and official dealings. As of January 1, 1978, many common units are no longer to be used. They have been replaced by less familiar units.


Osteogenic sarcoma complicating osteogenesis imperfecta tarda. We describe the case history of a 13 years old boy who developed osteogenic sarcoma of the left thigh, six years after diagnosis of osteogenesis imperfecta tarda with a positive family history. Only four other patients with this disease combination are reported in the literature. Preoperative treatment with high-dose Methotrexate caused marked tumor regression, as shown at examination of amputation material. The inter-relationships between the two disorders are discussed and the literature is briefly reviewed.


Developing molar occlusion.

Developing molar occlusion. This article has focused on developmental changes in molar occlusion. Its purpose is to alert the reader to changes in these relationships, which can occur naturally from birth to the period of developed dentition. The practitioner should be cognizant of these changes and the importance of preserving and promoting good molar relationships, which are the foundation of occlusions.


Application of analysis of crowding and spacing of the teeth. Spacing or crowding of the teeth is measured and analyzed to assist in decisions regarding the maintenance of teeth in their existing positions or their movement to improved positions. Numerical guides always should incorporate a gray zone in which decisions cannot be made without additional information. In the stage of mixed dentition, estimates of the size of unerupted teeth are more accurate than estimates of future spacing or crowding because the perimeter of the arch does not diminish the same amount in all cases. Instead, it appears to be related to the amount of crowding in the mixed dentition. Determination of the amount of crowding or spacing must always be accompanied by consideration of molar, canine, and incisor relationships. In addition, the effect of the dentition on lip posture should also be evaluated.


Space control in the primary and mixed dentitions. Space control has been distinguished from space maintenance. The difference is not a semantic one. Space control calls upon the dentist to apply his knowledge of occlusal development to the patient's condition. It infers assessment and re-evaluation. Space maintenance, unfortunately, sometimes becomes a routine or mechanical placement of appliances. This article has reviewed some of the variables to be considered when effecting space control: the factors that dictate appliance selection and some of the more common appliances used for space control today. No formula has been recommended for the application of appliances. Rather, the dentist has been urged to review the variables and re-evaluate his decisions according to the dynamic development of the patient's dentition.


Digital sucking and tongue thrusting in children. A conservative approach to the management of the child and parent and to the treatment by the dentist for both digital sucking and tongue thrusting is advocated. Because the prevalence of both activities continues to decrease with age, various age ranges are selected as guidelines for the dentist in selecting an approach for the management and treatment of either activity. Successful closure of an anterior open bite after the cessation of digital sucking and tongue thrusting is directly related to the ability of the dentist to assess the growth pattern and especially to determine whether there is a skeletal component contributing to an increase in the certical dimension.


Principles of design of active and removable appliances. Removable orthodontic appliances, perhaps more than any other form of mechanical therapy for the movement of teeth, are applicable to general practice. Far too frequently, however, the clinician limits his appliance design to a selective number of appliances with which he is conversant and attempts to modify any one of them to fit a specific situation. This article suggests a different approach. A specific appliance has not been recommended for a specific situation. Instead, the principles of removable appliance design have been elaborated upon according to an established plan. Adherence to the principles should enhance the clinician's ability to provide a more effective and efficient service for his young patients.


Maxillary anterior displacement and impaction in the mixed dentition. Attention has been given to problems of eruption in the maxillary anterior region. It is a region where a variety of anomalies occur. Since the maxillary anterior region influences appearance so greatly, early detection of difficulties and careful planning and treatment can be extremely beneficial to patients.


Regaining space in the mixed dentition.

Regaining space in the mixed dentition. Space-regaining therapy is an important treatment modality in the management of developing occlusions. Success is dependent on recognition of relationships and forces not seen when attention is focused only on the dental segment containing the lost space. This article has discussed other considerations for determining when to treat, as well as offering suggestions concerning types of appliances useful in treatment. A case was used to demonstrate the diagnostic procedure and appliance design.


The monoblock appliance.

The monoblock appliance. While the use of this appliance would appear to require relatively litlle operative time, it must be clearly understood that the function of this appliance is not as predictable as that of other types of removable devices. Under such circumstances, it is of great importance to ensure that a correct diagnosis and evaluation of the original condition has been made relative to the listed criteria; all factors must be considered and no diagnosis should be made purely and simply on the basis of an obvious increase in overjet and a class II malocclusion. In addition, the personality and nature of the patient is of paramount importance, since it is his cooperation and interest that in the end will lead to successful therapy.


The quality of life of the dentist.

The quality of life of the dentist. That elusive concept 'quality of life', which has become a topic of increasing concern in this day among members of the dental profession, has been examined in the light of findings in the behavioral sciences and those of the medical sciences, particularly morbidity and mortality studies. A review of the literature reveals too few studies in the behavioral sciences; and those that do address the problem do so obliquely. Findings from morbidity studies are controvertible. One recent large-scale study of mortality identified no excess mortality from particular causes among United States white male dentists as a group--this included the much often talked about 'excess of suicide'. The position maintained is that the quality of life of the dentist is good relative to other professions or labors in the absence of 'hard' data to the contrary. A plea is made for additional studies in the future and a continued and cooperative association of medical and behavioral scientists to monitor the 'total health' of the profession.


The quality of life of the dentist as perceived by society. Research dealing with the public's perception of the quality of life of the dentist is not well developed. Generally, the approach of researchers to this topic has been to examine the public's image of the dental profession. Specifically, the degree of prestige attributed to the dental profession by the public has attracted major attention. A review of studies reveals that while the profession enjoys relatively high prestige, it is extrinsic factors rather than the intrinsic value of the service that determine the public's image. The dental health care system and dental education as presently structured do not appear to be serving the bast interest of the public. The paper concludes with a discussion of what are considered to be major issues that the dental profession both in Canada and elsewhere will have to deal with in the coming years, in order to bring about change both in its image and the generally low utilization of the services it provides.


The oral health of adults in the Baltimore SMSA study area. This study, carried out in the region including Baltimore, Maryland, USA followed the pattern previously reported in the studies in Australia, New Zealand, Norway, Germany and Japan (Int. dent. J. 1976, 26, 317). In this area dental care is provided predominantly by payment of fees for service in private practice. Details are given of the oral health status in terms of caries, periodontal disease and loss of teeth for a group of 1142 adults aged between 35 and 45. Using the WHO stepwise regression analysis the significance of the previously reported predictors for each of the variables examined was determined. Finally a comparison is made between the present findings and those from an earlier National Health Survey carried out between 1960 and 1962. This suggests that while the caries situation may have improved over the past fifteen years, periodontal disease and loss of teeth have increased.


Relevance of circulating immune complexes in childhood acute lymphoblastic leukaemia. Circulating immune complexes have been measured using the (125I)C1q binding test in 216 sera from 135 children with acute lymphoblastic leukaemia. Increased circulating immune complexes were detectable in 10.7% of the sera and 10.4% of the children. There was no correlation between the presence of circulating immune complexes and prognosis, but a strong correlation with a history of recent infection.


[In vitro study of the role of periosteum and the periodontal ligament in the bone repair process]. For the study of the role of periosteum and periodontal ligament in the phenomena of bone repair, fragments of palatal mucosa and maxillary or mandibular bone from adult rats and devoid of periosteum were cultivated in association. The survival went beyond 26 days. In the bone, the ligament side showed by the 12th day signs of osteogenesis, whereas the other side devoid of periosteal osteoblasts showed empty lacunea, as it is observed "in vivo".


[Oral nerve endings in the cat].

[Oral nerve endings in the cat]. The oral nerve endings of the palate, the buccal mucosa and the periodontal ligament of the cat canine were characterized by the presence of a cellular envelope which is the final form of the Henle sheath. The structures described as end-rings in the periodontal ligament are more probably subterminal nervous structures rather then receptors. They are not specific to the ligament. They can be observed in the palate and in the buccal mucosa where, as in the periodontal ligament, mechano-receptors of the Vater-Pacini type can be seen.


[Histological studies of normal and pathological furcations in the rat]. In order to study the histological structure of healthy and pathological furcations in the rat, two groups of animals were submitted to two different diets: one normal and one rich in sucrose. In the first group, certain particularities were demonstrated in the periodontal ligament in the interradicular region: the fibrous network was very loose in this zone and the fibrous insertions were essentially cemento-cemental and not cemento-osseous. In the rats submitted to the high sucrose diet, a disequilibrium was noted between the apposition zones and the zones in bone and cementum resorption.


[The brown line of Retzius in scanning electron microscopy]. A study in scanning electron microscopy of the striae of Retzius of human enamel, on longitudinal and transverse sections, has shown thin striae and relatively broad bands. The thin striae of Retzius consisted in narrow zones devoided of mineral material which extended obliquely through the prisms. These latter were interrupted at the level of the striae. A thin dense layer bordered sometimes unilaterally the striae of Retzius. The relatively large band-like structures involved several prism rows and can be considered as hypomineralized enamel.


[Gas chromatography analysis of volatile monocarboxylic aliphatic acids (C2 to C6) of 15 strains of Veillonella of oral origin]. A qualitative and quantitative study has been carried out on 15 strains of the Veillonella genus, isolated in the oral cavity. Following two methods of preparation of samples for injection in a chromatograph GL, we have identified among the volatil monocarboxylic aliphatic acids from C2 to C6 the glucose fermentation products of these different strains. With the same methods, we studied in parallel these products from strains A.T.C.C. 10790-17444 (Veillonella parvula) and 17445-17446 and 17447 (Veillonella alcalescens). The results, despite the diversity of origin of all these strains, based on physiological and biochemical characteristics, confirm that volatil monocarboxylic aliphatic acids are characteristic of a genus specificity and not of a species. The presence of acetic acid, proprionic acid and iso-valeric acid was shown


Stimulation of protein synthesis by hemin in extracts of Friend erythroleukemia cells. Extracts prepared from Friend erythroleukemia cells were highly active in translating endogenous mRNA and a consistent 2-fold stimulation by hemin was observed. When extracts were treated with micrococcal nuclease and incorporation was dependent on exogenous globin mRNA, there was more significant stimulation by 37.5 micron hemin and greater than 10-fold stimulation by 75 or 150 micron hemin. The effects of hemin were not strikingly different in extracts of dimethyl-sulfoxide-induced or uninduced cells. The results could reflect an effect on initiation of protein synthesis analogous to that in rabbit reticulocytes.


Reversed-phase high-pressure liquid chromatography of some tryptamine derivatives. A quantitative reversed-phase high-pressure liquid chromatographic method is described for tryptamine, bufotenine, N-methyltryptamine and N,N-dimethyl tryptamine. All compounds were eluted with base-line separation within 15 min. The method is used to determine the tryptamine level in a leaf extract of Acacia podalyriaefolia A. Cunn. Satisfactory recoveries of tryptamine from plant material, and N,N-dimethyltryptamine from urine were obtained.


Errors in the assessment of pocket depth in vitro. The inaccuracy of the calibration of two Merritt-B probes, old and new style, was investigated. It appeared that the calibration of the Merritt-B "new style" probe was better than the calibration of the old one. The influence of the mode of calibration and the reading of the calibration on pocket depth assessment with a Merritt-B "old style" probe was studied in an in vitro model. The model consisted of 32 aluminium cubes each with a hole in the centre. The holes were 1 mm in cross-section and the depth varied from 0.25 mm to 8 mm in 0.25-mm increments. Results show that pocket depths of 1 mm to 8 mm +/- 0.25 mm generally were read correctly about 90% of the time. This was not true for the 4- and 6-mm areas. When a probe was used where the 4- and 6-mm marks were omitted, pocket depth in that area were read correctly only in about 60% of instances. This difference disappeared when the 4- and 6-mm marks were added. Results of measuring the half millimeter values showed that generally 80% were recorded as the lower whole millimeter.


Comparison of the in vivo and in vitro antibacterial properties of providone iodine and chlorhexidine gluconate mouthrinses. Clinical and laboratory studies were carried out to compare the antibacterial properties of two antiseptic mouthwashes, namely 1% povidone iodine and 0.2% chlorhexidine gluconate. In a group of 10 subjects after a single rinse with povidone iodine, an immediate mean fall in total salivary aerobes and anaerobes occurred, followed by a return to normal levels by 1-hour postrinsing. With chlorhexidine gluconate a similar but greater reduction in salivary bacterial counts was observed, which was still present up to the 7-h postrinsing period. Saliva samples obtained from the subjects 2 min after rinsing with providone iodine produced little or no inhibition to the growth of a test organism in vitro, whereas following chlorhexidine gluconate, antibacterial activity was present in the saliva specimens up to the 3-h sampling time. Using culture media containing comparable levels of soluble protein to saliva, the minimum inhibitory concentrations of povidone iodine against several standard test organisms were much higher than those of chlorhexidine gluconate. The results suggest that povidone iodine, as a mouthwash, exerts only an immediate antibacterial effect and unlike chlorhexidine, is not retained at antibacterial levels within the oral cavity after expectoration. This lack of prolonged action of povidone iodine in the oral cavity would appear to be relevant to its reported lack of antiplaque activity.


Transient, severe periventricular hypodensity after leukemic prophylaxis with cranial irradiation and intrathecal methotrexate. Serial computed tomography (CT) demonstrated complete resolution of severe periventricular hypodensity occurring in a child after receiving prophylaxis for acute lymphocytic leukemia. The resolution of this encephalopathy suggests that early changes of subacute necrotizing leukoencephalopathy are reversible and CT is copable of detecting these early changes.


Nursing habits and dental decay in infants: "nursing bottle caries". The decay-producing capabilities of certain foods can be influenced by eating habits. When a habit of frequent nocturnal bottle or breast feeding is maintained beyond a year of age, the potential for gross dental decay in very young children is established. Bovine milk, milk formulas and human breast milk have all been implicated in the condition of "nursing bottle caries," because of their lactose content. Additional sweeteners in the nursing bottle, the use of fruit juices or the use of honey-dipped pacifiers can also cause "nursing bottle caries." "Nursing bottle caries" can be prevented through a timely educational program to new parents. Prevention is particularly applicable in young children, since a healthy oral condition promotes good nutrition, a healthy state and normal growth. Both the American Dental Association and the American Society of Dentistry for Children have pamphlets explaining "nursing bottle caries," which are available for distribution to the public.


Premature loss of primary teeth: part I, its overall effect on occlusion and space in the permanent dentition. Premature loss of primary molars causes, without doubt, permanent changes in regard to space and sagittal molar relations, in the permanent dentition. The changes are due to drifting of teeth and lack of growth, and such changes should, whenever possible, be prevented. In part two of this series of papers, a further analysis of the data will be presented.


Ankylosed primary molars.

Ankylosed primary molars. The prevalence of ankylosis of primary molars was found to be 3.7% of the sample subjects. Eighty-two of the 2234 children examined exhibited ankylosis. The prevalence of ankylosis among the black children in the sample was much lower (0.93%) than that of the white children (4.10%). The mandibular first primary molar was ankylosed at an earlier age and more frequently than any other tooth. The frequency of ankylosis of the second primary molar increased in older children. The high incidence of ankylosed primary teeth was seen in children between seven and eleven years of age. Treatment should be based on the evaluation of growth potential jeopardized by the condition. Early extraction and subsequent space management, especially in the younger patient, is recommended.


Use of a continuing health history in dental practice: a survey. The authors strongly recommend the routine use of a continual-health-update procedure at each recall appointment. The updated health-histories allow us to better evaluate the "whole" child. We have found that the parent appreciates not only the initial inquiry, but also the continuing concern about illnesses and injuries the child may have incurred since the last dental examination. The inquiries help build rapport between the families and the professional staff of our office. In addition, they upgrade the level of professional care provided.


Determination of arbitrary tooth displacements. The noninvasive, modern technique based on the method of double-exposure hologram interferometry was used to measure arbitrary displacements of teeth in the three dimensional space. The experimental studies were carried out on an idealized model of the maxillary central incisor. The results show that the experimental data, based on component loading, are inadequate to accurately predict tooth displacement from an arbitrary force acting in the three dimensional space.


Relaxation of orthodontic elastomeric chains and modules in vitro and in vivo. Relaxation patterns for two orthodontic polyurethane-based elastics have been quantified in dry air and water bath environments and in vivo. Water bath simulation of in vivo behavior is apparently valid for up to a week following initial activation, but it becomes somewhat erroneous thereafter.


The use of film thickness to measure working time of zinc phosphate cements. A method is proposed to quantify the working time of zinc phosphate cement based on sequential measurement of viscosity. The method was used to measure the extension of working time resulting from reduced mixing temperatures. Premixing small amounts of powder prior to standard mix was shown to be ineffective at extending working time. The addition of water to the cement was shown not to affect working time but did decrease the setting time of the cement.


Clinical study of dental cements. VII. A study of bridge retainers luted with three different dental cements. In a clinical study of three luting cements, 547 bridges and 162 crowns were permanently cemented. Patients were recalled at 6-month intervals and the restorations were examined for looseness. A pattern of retainer type, cement type and retainer success was demonstrable.


TMJ symptom severity and EMG silent periods. The hypotheses that latency or duration of the EMG silent period evoked by a tap to the chin during a maximal clench would be more prolonged in more severe TMJ patients were tested. The mean latency did not, and the mean duration did, increase significantly with increased severity of TMJ dysfunction.


Finite element stress analysis of a class I amalgam restoration subjected to setting and thermal expansion. Stress analyses are presented for a second mandibular premolar with a class 1 amalgam restoration. The effects of amalgam setting and thermal expansions are examined. An axisymmetric representation of the structure is used and the analyses are carried out by the finite element method. Lined and unlined restorations are compared with regard to the principal stresses set up in the composite structures and also the patterns of deformation incurred. The effects of various enamel and dentin stiffness combinations are also considered.


New information on high copper amalgam corrosion. Anodic polarization of "pure" Cu6Sn5 was investigated. Cu6Sn5 is found to be passive in nearly neutral synthetic saliva. Anodic corrosion activity (characteristic for tin) previously reported for a high copper amalgam must result from the presence of the gamma2 phase or tin in the matrix phase.


The growth of calcium phosphates on hydroxyapatite crystals. The effect of fluoride and phosphonate. The nature of the calcium phosphate phase which precipitates on hydroxyapatite seed crystals can be controlled by varying the HAP seed concentration. At low seed concentrations, dicalcium phosphate dihydrate (DCPD) is formed while at high seed levels a more basic phase precipitates. It has been found that fluoride ion increases the percentage of basic phase that crystallizes while ethylidenediphosphonic acid encourages the formation of DCPD. This behavior is explained by the competition between the nucleation of DCPD and the crystal growth on sites already present on the HAP seeds.


Semiconductor probe measurements in beagle pups during deciduous tooth development. Bone-seeking radiopharmaceuticals were used together with clinical and radiographic procedures to study tooth development in dogs. Similarities in the pattern and time course of radiopharmaceutical uptake in jaw areas studied suggest that changes in alveolar bone metabolism are not closely related to eruption times of individual teeth.


Alteration of lidocaine-induced convulsions by meperidine and nitrous oxide. When mice were pretreated with meperidine, the incidence of lidocaine-induced convulsions was increased. Nitrous oxide-oxygen (N2O-02) offered no protection against convulsions caused by lidocaine alone but lowered the incidence of lidocaine-induced convulsions of mice pretreated with meperidine.


The viability of microorganisms in carious lesions five years after covering with a fissure sealant. Carious lesions that were covered with a pit and fissure sealant for five years yielded bacterial cultures that were predominantly negative. Sixteen of 18 test sites judged to have active caries in 1972 were found inactive in 1977; ten of 12 sites suspected to have caries in 1972 were deemed to have inactive caries in 1977. Sealant treatment resulted in an apparent 89% reversal from a caries-active to a caries-inactive state. These data confirm and extend previous observations that a limited number of cultivable organisms persist in some lesions but their numbers are few, and they do not appear capable of continuing the destruction of tooth structure.


Surface characteristics of resin-coated composite restorations. Twenty-four maxillary anterior composite restorations from a clinical study of resin coating were examined at the time of baseline evaluation and at 23 months; electroplated positive replicas, impression negative replicas, and SEMs were used for evaluation. Coated restorations had smooth surfaces after 23 months, in comparison with rough surfaces of uncoated restorations. Defects in some of the resin coatings were found at the time of baseline evaluation; these included isolated areas of the composite or etched enamel that were not covered by the resin. Later examinations showed cracking of part of the edges of resin coating, development of bare areas, thinning of the coating edges, or generalized loss of the protective coating. The defects seen immediately after placement of the coatings were probably caused by errors in technique that include: application of the resin in a layer that was too thin; surface contaminants in the area of application; moisture on the surface of the composite or enamel; and areas of inadequate enamel etching were adjacent to the cavosurface margin of the composite. The appearance of bare spots or total loss or thinning of the resin coating edges during the later examinations is caused by wearing or abrading of the resin coatings from natural or mechanical causes. This seems to be a function of the initial coating thickness and its location on the tooth.


Oral complications in patients receiving treatment for malignancies other than of the head and neck. Oral complications in patients being treated for malignancies that were not in the head and neck were studied. Age, type of therapy, and type of malignancy were factors related to the prevalence of oral complications. Mucosal ulcerations, xerostomia, and bacterial and fungal infections were the most frequently encountered oral problems. The frequency of oral complications in these patients indicates the need for an awareness and involvement of dental practitioners in their management.


Past infection with hepatitis B virus in patients at a dental school. Samples of blood from 327 new patients at a dental school were tested by radioimmunoassay for the presence of hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs). The data were compared to the patients' histories of hepatitis. Through a statistical analysis, it was indicated that significant numbers of patients with no history of hepatitis had been infected with hepatitis B virus.


Endodontic-orthodontic management of fractured anterior teeth. A case history is presented of a 10-year-old patient, who accidentally injured her maxillary central incisor. The fracture of the crown extended 2 mm below the crest of the alveolar bone. After a pulpotomy was done as a temporary measure, orthodontic appliances were placed by bonding brackets on the maxillary anterior teeth and fitting a sectional arch wire to extrude the fractured tooth. After successful extrusion, the fracture line was brought above the level of alveolar bone where successful restoration of the tooth by the acid-etch method could be accomplished.


Intraoral third molar transplants: report of three cases and long-term follow-up. Preserving the interproximal space of extracted first molars in young adults can be accomplished in many ways. The procedure described in this report uses the third molar as a replacement and has proved successful when all conditions are favorable.


An interdisciplinary approach to the dental care of the mentally disabled. In institutions for mentally disabled persons, dental care of the patient is often difficult because of uncooperative behavior. Premedication is sometimes necessary. The mentally disabled patient frequently receives other medication for behavioral control, cerebral palsy, seizures, or the like, that may interact with the dental premedication. Because of the problems that may develop, a program between an institution's dental department and a university's clinical pharmacy department was developed that provided an approach to the selection of premedication for the dental patient who is mentally disabled.


Evaluation of the normal range of vertical mandibular opening in children and adolescents with special reference to age and stature. 1050 subjects between 5 and 19 years of age were examined to determine the normal range of values for maximum vertical mandibular opening and incisal edge distance. As a result of subsequent statistical evaluation, it can be stated that mouth opening depends to a significant extent upon age and stature. For the determination of "normal" mandi opening, the minimal value using incisal edge distance is 35 mm for 5-to 10-year-old children and 38 mm for 11- to 19-year olds. The corresponding values for alveolar crest distance is 44 mm and 49 mm. Determination of "normal" mandibular opening using the alveolar crest distance seems superior to that of incisor edge distance and should be recommended for universal use in general practice.


Surgical correction of cartilaginous nasal septum deformities. Septal cartilage deviations which are usually present in deformities of the cartilaginous nasal septum are corrected by scarification on the concave side of the curvature. Histological studies indicated that this procedure was best adapted to the structure of the elastic fibres constituting the cartilaginous nasal septum. Follow-up examinations in 33 patients who having undergone surgery showed nasal breathing to be unobstructed bilaterally in all cases; in 29 patients an aesthetically satisfactory nasal shape was restored and full re-alignment of the cartilaginous nasal septum was obtained.


Photo-cephalometric analysis in treatment planning for surgical correction of facial disharmonies. A full understanding of soft tissue behaviour, including muscle action, and the correct diagnosis of the basic bony discrepancies are essential to the success of operations for the correction of facial disharmony. In the author's experience, cephalometric measurements are invaluable in obtaining a correct diagnosis of the facial disharmony and once mastered make these operations more interesting for all concerned. Unfortunately, traditional cephalometric measurements, although useful to orthodontists, are tedious and often misleading to oral surgeons. This article describes a much simplified and accurate method of photocephalometric diagnosis and prediction used in conjunction with the method of Archial Analysis as suggested by Sassouni (1955, 1958, 1974).


Facial duplication -- the unique case of Antonio. A case of facial duplication with its surgical correction in childhood and the consequences on facial growth is reported. It is a unique case in the duration of observation. The following structures were fully duplicated: the nose, the premaxilla, the cribriform plate, the crista galli. In addition there was an enormous facial cleft including lip, alveolus and palate. Additionally there were two rudimentary eye sockets, eyes, and two supplementary eyebrows. The monstrous hypertelorism with the facial duplication was corrected at the age of ten. The surgical procedure is described and the postoperative complications are discussed. Gross lack of growth of the middle third of the facial skeleton was observed. This was probably the consequence of the initial corrective surgery. Overgrowth of the mandible created a gorilla-like appearance by the end of the growth period. This was corrected in one operation by advancement of the middle third in three sections and repositioning of the mandible as a whole together with the mandibular anterior alveolar segment. Finally all parts of the lower half of the nose had to be enlarged, both soft tissues as well as the cartilaginous framework. A pharyngoplasty in addition to the correction of the intermaxillary abnormalities did much to improve the speech quality of the patient. A large secondary cranial defect was successfully reconstructed with the use of 14 halved ribs. In spite of the removal of four ribs from one side and three ribs from the other, there were no postoperative respiratory problems. Spontaneous rib regeneration was found where ribs had been removed one year earlier.


Sagittal splitting and bicortical screw fixation of the ascending ramus. We describe here a procedure for osteosynthesis following sagittal splitting of the ascending ramus of the mandible. We use screws inserted through both cortical plates. The intraoral approach is combined with our method of transcutaneous drilling. The survey of our 6 years' experience showing the correction thus obtained provides very satisfactory long term stability.


Anaesthetic experiences in orthodontic surgery. The anaesthetic experiences and problems have been analysed, based on 100 orthognathic operations. The material includes all kinds of operations; operating time was about 4 hours, except for 8 very extensive procedures, lasting 6--7 hours. The importance of adequate premedication is emphasized. The use of nasal drops for decongestion is especially highly recommended for the prevention of bleeding during nasal intubation. An armoured nasal tube is always used; however, special care must be taken to detect leaks on the cuff. On four occasions the tubes had to be changed because of leaks in the cuff. The most annoying complication was tachycardia, due to: insufficient premedication, insufficient analgesics during operation, or the use of hypotensive drugs. Blood loss was clearly diminished by controlled hypotension. Postoperative vomiting was prevented by the use of a nasogastric tube for the first 6--8 hours. Major complications were not encountered.


Chronic mechanical trauma in the aetiology of oro-pharyngeal carcinoma. Tumours of the oral cavity and the oropharynx account for 12% of the malignancies in our patient material. The group of patients included a high percentage of smokers (83%), heavy drinkers and persons neglectful of oral hygiene. The majority of the patients mainly male were labourers or (small) farmers. In contrast to other reports in the literature, chronic mechanical trauma due to sharp remaining teeth, less than ideal fillings, badly fitting dentures or unsuitable denture-bearing tissue, and loose anchoring attachments were frequently present. Commensurate with the clinical findings, permanent damage to the covering squamous epithelium was demonstrated histologically. In addition to all forms of inflammation, parakeratosis and hyperkeratosis, dysplasia, including carcinoma in situ, and manifest carcinomas also presented. Surface-inert dentures and regular oral hygiene must therefore be considered an important requirement for the prevention of oral-cavity carcinoma.


A new method for the closure of a cleft palate. Contrary to the advocated linear approximation of the muscles in closure of the soft palate we have developed a different method which finds its anatomical confirmation in a publication by Kriens. Since we normally have intermingling vertical and horizontal muscle fibres within the soft palate it seemed logical to copy nature by the surgical technique. We believe that we are better able to reestablish normal anatomical findings by two opposing Z-plastics compared with the methods previously described. With this procedure we are also able to shift the centre of muscle function further dorsally, thus achieving a lengthening of the palate as well. Since the procedure is quite atraumatic on account of the oblique cuts, we seldom see tissue dehiscenses and have been able to observe a well functioning palate.


The importance of accurate records and follow-up in patients with oral cancer. A standardized patient record sheet is proposed to be used for all patients diagnosed as having oral squamous cell cancer. Such records would ensure thorough data recording and whilst providing accurate and complete information for retrospective and prospective analysis and research would also improve the follow up of such patients.


Credibility of morphologic and psychologic theories of TMJ pain-dysfunction aetiology. An evaluation of the morphologic and psychologic theories of the aetiology of TMJ pain-dysfunction can be revealing if made without resorting too much to scientific experimental results, because the interpretation of results as well as the questions asked are largely dependent on a prior commitment to one of the theories. Accepting that the TMJ pain-dysfunction became a common disease after the industrial revolution gives reason to look for a causative factor connected with it. Both an increase of psychologic stress and a change of dental morphology and function appear as possible factors, but only the latter has factual evidence. The lack of functional wear disturbs the unconscious swallow reflex but apparently not mastication. This suggests that retrusive interferences are a necessary but not always sufficient condition for the initiation of the TMJ pain-dysfunction. Psychologic factors are contributory, they can cause tooth clenching and perhaps grinding, but there seems to be no reason other than interferences from occlusion for that taking place eccentrically. Thus psychogenic tooth clenching and grinding do not seem to be pathogenic without the morphologic factor.


Ultra-violet absorption by two ultra-violet activated sealants. Since the ability of u.v. setting pit and fissure sealants to set in depth is dependent on the penetration of the u.v. radiation, the absorption coefficients of Nuva-seal and Alphaseal were determined at 365 nm, the wavelength of radiation used to polymerise both materials. Nuva-seal and Alphaseal had absorption coefficients of 0.165 mm-1 and 6.25 mm-1, respectively. The u.v. fluorescent dye present in Alphaseal contributed 2.5 mm-1 to its absorption coefficient and the remaining absorption was due to the 5% w/w catalyst concentration present, since the basic resin had no significant absorption. Therefore Nuva-seal may set adequately to the depths required of fissure sealants, but Alphaseal may not, unless a very high intensity u.v. source is used. A reduction in the catalyst concentration and the removal of the u.v. fluorescent dye might improve the setting characteristics of Alphaseal.


The effect of finishing on the anodic polarization of high-copper amalgams. The influence of surface finishing procedures on the corrodibility of high-copper amalgams was measured. Anodic polarization curves were determined in Ringer's solution for amalgam samples made from a dispersion and a ternary alloy. Three types of finishes were compared: as carved, burnished, and polished. The polarization curves of the burnished and polished specimens were statistically similar (P greater than 0.05) at all potentials investigated. The carved samples exhibited higher corrosion currents at most of the potentials investigated.


Size of variables in mandibular movements in autopsy material. Autopsy was performed on the right temporomandibular joint in eleven individuals with a mean age of 71 years. Standard positions indicative for protrusion, laterotrusive border movement and posterior opening movement were photographed in the sagittal plane. Size of movements of the disc and condylar head were recorded, as well as movements of a reference point in the mental region. The slope of the anterior discal movement was estimated and mandibular rotation during posterior opening was registered. Centre of rotation during the hinge movement was in all cases located to the craniodorsal part of the condylar head. Attempt to construct centres of rotation in the eminence and condylar head for the horizontal movements was in vain. The discussion deals with the influence of the specific kind of material on the results and the possible systematic differences to clinical material.


Viscoelastic properties of elastomeric impression materials. II: variation of rheological properties with time, temperature and mixing proportions. The variation of torsional shear modulus with time for several commercial elastomeric impression materials has been determined. The effects of mixing proportions and temperature on rheological properties are presented. The relevance of these properties to the actual use of these materials are discussed.


The cavity sealing ability of composite restorations subjected to thermal stress. An artificial caries technique, using a diffusion controlled acidified gel, was used to create in vitro artificial lesions adjacent to composite restorations. Prior to gel immersion, test specimens were temperature-cycled in a machine designed specifically for this purpose. Examination of control specimens showed little evidence of leakage, the presence of a cavity wall lesion being used as an indication of leakage. Compared to the controls, the test specimens showed either a reduction or no change in leakage pattern. It is suggested that thermal percolation may not be of clinical significance in relation to composite restorations.


Undercut reproducibility of functional impression materials (tissue conditioners). Impressions of a laboratory model of an edentulous ridge were made with three commercial tissue conditioners (FITT, Hydro-Cast and Coe-Comfort). Combinations of undercut dimensions and tray relief were tested by using three different sized trays with each tissue conditioner. Greater tray relief increased the accuracy of all materials tested; increasing ageing time from 7 to 24 h resulted in little change of accuracy of the stone models poured from the impressions taken.


Characterization of hydroxyapatite powders and compacts at room temperature and after sintering at 1200 degrees C. Synthetic HAP made in the laboratory as 'synthetic bone' may be a possible replacement or repair material, since the mineral phase of dental hard tissue and bone is essentially hydroxyapatite in form. Hydroxyapatite or modified compositions of HAP appear to offer possibilities as a substitute for the original material provided by nature. A high surface area (70.4 m2/g) commercially available hydroxyapatite (HAP) of poor crystallinity was converted to a highly crystalline HAP through sintering at 1200 degrees C in an atmosphere of steam and nitrogen. Compacts were made of the powdered HAP from 500 to 25,000 psi and sintered under the same conditions. The changes in the resulting pore volumes, pore sizes, pore size distributions, densities, and surface areas of the sintered compacts were determined by mercury porosimetry. A 20-fold reduction in open pore volume for sintered compacts was observed. For compacts made at pressures above 5000 psi, the reduction in open pore volume was compensated for by the formation of closed pore volume. The sintering mechanism was attributed mainly to neck formation, growth between particles, diffusion, and plastic deformation.


Closure of the patent ductus arteriosus with ligation and indomethacin: a consecutive experience. This report summarizes a consecutive experience with 59 preterm infants with clinical, radiographic, and echocardiographic findings of a large patent ductus arteriosus. Thirty-five infants who met defined criteria received indomethacin, and 24 infants underwent PDA ligation. Analysis of the clinical course of these infants revealed no selective indomethacin morbidity and suggests that infants undergoing ligation require more prolonged ventilator therapy with increased exposure to FiO2 greater than or equal to 0.3. Mortality rates between ligated and pharmacologically treated groups were similar. This study documents that inhibition of prostaglandin synthesis to constrict and close the PDA in the premature infant is an effective alternative to operative closure.


Placement of free gingival grafts on denuded alveolar bone. Part I: clinical evaluations. Fourteen patients were examined and determined to lack an adequate zone of attached gingiva in the mandibular incisor region. Each patient was treated on the left side of the mandible by placement of a free gingival graft on denuded bone and 12 of the 14 patients received a free gingival graft on retained periosteum in the right mandibular anterior region. Two patients were treated on the right side by either bone denudation or periosteal bed preparation without graft placement to permit histological evaluation of wound healing under these circumstances. Grafts were retained for time intervals from 1 week to 24 weeks. All patients were evaluated clinically for graft "take", graft healing, graft shrinkage, and graft mobility.


A case report of unusual dental calculus formation. A case is presented in which an unusual amount of intraoral calculus was seen in a 59-year-old woman. The deposits completely covered all surfaces of most teeth and extended over the facial and lingual gingivae. The relationship between certain chemical salivary parameters and heavy calculus formers is briefly described.


The effectiveness of in vivo root planing in removing bacterial endotoxin from the roots of periodontally involved teeth. In this study, scaling alone resulted in endotoxin values considerably greater than the values for healthy root surfaces. However, the root-planed Samples contained only about 1 ng more of endotoxin than did the healthy root surfaces. This small difference can be accounted for by the presence of small flecks of calculus left after root planing. Considering that out of a total sample size of 48 surfaces there was only 1 ng difference in the amount of endotoxin between planed teeth and uninvolved teeth, the basic conclusion must be that root planing, as performed in this study, was able to render diseased root surfaces approximately as free of detectable endotoxin as were uninvolved, healthy root surfaces of unerupted teeth.


Treatment of localized gingival recessions. Part I. Lateral sliding flap. This study was undertaken to evaluate biometrically the changes that occur on the recipient as well as on the donor tooth with regard to gingival recession, sulcus depth and width of keratinized gingiva after performing a lateral sliding flap in the treatment of localized denuded roots. Fourteen teeth with gingival recession were treated using a lateral sliding flap. Measurements were recorded preoperatively and 1, 3 and 6 months after surgery. A mean gain of 2.69 mm of soft tissue coverage over the denuded root was found 6 months postoperatively which represents 69% of coverage. The mean gain in width of keratinized gingiva averaged 3.15 mm. On the donor tooth an average gingival recession of 1.1o mm was found after 6 months, and the width of keratinized gingiva decreased an average of 1.25 mm. Results remained stable after 30 days postsurgery.


Treatment of localized gingival recessions. Part II. Coronally repositioned flap with a free gingival graft. Fourteen teeth with localized gingival recessions were treated using a coronally repositioned flap with a free gingival graft (Bernimoulin, 1973). The second step of the procedure was performed 1 month after the free gingival graft was done. Clinical measurements of the recession, sulcus depth and keratinized gingiva were taken preoperatively and at 30, 90 and 180 days after surgery. A mean reduction in the recession of 2.73 mm was obtained after 6 months, which was equivalent to a 64% decrease of the original recession. A significant increase in the width of the keratinized gingiva, averaging 3.27 mm, was found after 6 months. All results remained stable after 30 days postoperatively. The values for gingival recession, sulcus depth and width of keratinized gingiva on the teeth adjacent to the recessions remained unchanged, since they were undisturbed by the procedure.


A comparison of biofeedback and occlusal adjustment on bruxism. Within the limits of this study and with the reported assumption that the recorded EMG activity is related to bruxism, the results of this investigation suggest that the effect of biofeedback in reducing EMG activity is more consistent than an occlusal adjustment, possibly due to differences in the cause of the initial heightened EMG activity in the group of subjects studied.


Evidence for the maintenance of motoneurone properties by muscle activity. 1. Electrophysiological properties of soleus motoneurones in adult cats were examined with intracellular electrodes following alterations of activity of the soleus muscle induced by transection of the thoracic spinal cord or by conduction block of the muscle nerve with tetrodotoxin (TTX) cuffs. Attempts were also made to maintain muscle activity by daily stimulation of the maintain muscle activity by daily stimulation of the peripheral nerve. 2. Within 8 days after transection of the thoracic cord, soleus motoneurones showed a significant decrease in the duration of afterhyperpolarization following action potentials. This change in motoneurone properties induced by cord transection was prevented by daily stimulation of the sciatic nerve. 3. Soleus motoneurones showed a significant decrease in the duration of after-hyperpolarization within 8 days after conduction block of the soleus nerve with TTX. This change in montoneurone properties was prevented by daily stimulation of the nerve peripheral to the TTX cuff but not central to the cuff. 4. The soleus muscle showed a significant decrease in weight relative to body weight within 8 days after transection of the thoracic cord. This decrease in muscle weight following cord transection was prevented by daily stimulation of the sciatic nerve. 5. No fibrillation was detected in the soleus muscle 8 days after conduction block of the soleus nerve with TTX. The maximum twitch tension of the soleus muscle evoked by nerve stimulation showed no significant difference between the two sides treated and untreated with TTX. Fast axoplasmic transport measured with cholinesterase as a marker was not affected by TTX. Thus, there was no sign of functional although morphological abnormalities were found in some nerve fibres. 6. It is concluded that motoneurone properties in an adult depend partly upon some factors associated with activity of the innervated muscles and that such trophic signals are retrogradely carried by the motor axons.


Disparity of motoneurone and muscle differentiation following spinal transection in the kitten. 1. The spinal cord of kittens, 3--5 days of age, was transected at the lower thoracic level. Isometric contractions of the medial gastrocnemius and soleus muscles as well as intracellular potentials of their motoneurones were recorded after varying post-operative periods of up to 110 days. Similar observations were made 52--59 days after cord transection in adult cats. 2. In cord-transected kittens, contraction time of the gastrocnemius muscle showed normal development, whereas the soleus muscle failed to maintain slow contraction. In adult cats, cord transection increased the speed of contraction in the soleus muscle without significant changes in contraction times of the gastrocnemius muscle. 3. Soleus motoneurones showed a normal post-natal increase in the duration of afterhyperpolarization (a.h.p.) up to a certain stage (61--71 days in age) following cord  transection. However, the subsequent increase in the duration of a.h.p. of soleus motoneurones observed in normal kittens was lacking in cord-transected kittens. It is suggested that soleus motoneurones show two stages of differentiation in terms of the duration of a.h.p. 4. In adult cats, cord transection caused a decrease in the duration of a.h.p. of soleus motoneurones approximately to the value observed at the end of the first stage of differentiation in kittens. 5. The duration of a.h.p. of gastrocnemius motoneurones remained virtually unchanged follwoing cord transection in both kittens and adult cats. 6. The positive correlation between the duration of a.h.p. of soleus motoneurones and contraction time of the innervated muscle fibres normally observed in kittens and adult cats was absent following cord transection. 7. It was assumed that alteration s in contraction time of the muscle following cord transection are due to virtual elimination of motoneurone discharge and that the duration of a.h.p. reflects the discharge pattern of motoneurones under normal conditions. Based on these assumptions, a possible process for normal post-natal differentiation of motoneurone and muscle is proposed.


Dental esthetics and the golden proportion. A system of esthetic predictions is described that has been used since antiquity. The naturalness of the system is emphasized by showing examples from nature and how artists and designers use it. The application of this system to dental esthetics is facilitated by the description and inclusion of a dental grid for the anterior esthetic segment.


Central papillary atrophy of the tongue and denture stomatitis. A retrospective study of the epidemiologic data of 4,417 subjects has been undertaken to study the possibility of a link existing between glossal central papillary atrophy (median rhomboid glossitis) and denture stomatitis. Neither the association between glossal central papillary atrophy and denture stomatitis nor the association between glossal central papillary atrophy and denture use was statistically significant. However, the correlation between wearing removable dental prostheses and finding candidal mycelia in smears from these tongue lesions was statistically highly significant. Debilitation caused by general age changes would not appear to predispose to atrophy of the pappillae of the middle portion of the tongue-dorsum.


A new semiadjustable articulator. Part IV: an investigation of three semiadjustable articulators. In this study the compensating angle on the Hanau XP-51 articulator was found to be proportional to the magnitude of the intercondylar distance. Further, eccentric movement of the Hanau 130-7, the Hanau XP-51, and the Whipmix articulators, at the cusp level, followed that displayed by the control articulator when guided by straight condylar elements. For restoration to function harmoniously in the patient's mouth they must be made on an instrument that can accurately reproduce selected movements of the mandible. The choice of articulator depends upon the precision with which the dentist wishes to work. The mechanisms of articulators should be precise, easy to adjust, and simple to understand.


Histologic evaluation of electrosurgery with varying frequency and waveform. This investigation was designed to determine the differences in tissue alteration produced by electrosurgical machines with different carrier frequencies and waveforms. Histologic analysis showed that: 1. The machine with full-wave rectification and the lowest frequency of operation (machine I, 1.7 MHz) produced significantly greater tissue alteration in the superficial tissue layers than the full-wave rectification machines with higher frequencies of operation. 2. The continuous-output waveform produced significantly less tissue alteration in the superficial tissue layers than the modulated type at the same frequency of operation. 3. Histologically, the experimental defect showed a band of coagulation necrosis approximately 50 mu wide along the margin of the incision. Tissue destruction decreased laterally and inferiorly from the surface of the defect. 4. The experimental defect was similar in shape to the physical form of the cutting electrode.


The use of tongue-depressing stents for neuropathologic chewing. Comatose patients may develop a neuropathologic chewing reflex that results in self-inflicted oral trauma. Loss of coordination between the tongue and chewing cycle leads to maceration of the tongue and infection. The use of a tongue-depressing stent can keep the tongue from acting as a bolus and prevent perpetuation of the reflex chewing cycle and resultant self-injury.


Functional occlusal forces: an investigation by telemetry. In normal chewing the forces exerted on the occlusal surface seldom exceeded 10 to 15 pounds, as recorded by an eight-channel force transmitter in a removable fixed partial denture. Ninety-five percent of forces were less than 3.5 pounds for subject A, 2.0 pounds for subject B, and 10.0 pounds for subject C. The chewing frequency and the places of maximal force on the occlusal surface were relatively constant. The electromyographic chewing patterns could be considered normal in all circumstances. There was a remarkable statistically significant day-to-day variation in force values. The forces also changed for different kinds of food. The differences between maximum and minimum force values were highest in voluntary, nonfunctional movements.


Mechanical properties of tissue conditioners. Part II: creep characteristics. These static creep characteristics indicate that under functional loads Coe-Comfort could behave satisfactorily as a tissue-conditioning material for periods up to 1 week, particularly for the first 24 hours postinsertion. However, the absence of published data on the tissue loads exerted by dentures in their resting state precludes making judgments as to the absolute efficiency of any of these materials as tissue-conditioning agents. When the present results are considered along with those obtained in an earlier study (Part I), the following general conclusions can be made: 1. Coe-Comfort should exhibit the best tissue-conditioning characteristics of the materials tested. 2. F.I.T.T. should perform as the best functional impression material. 3. Lynal is distinctly different from the other two materials in its mechanical properties. Its much greater stiffness coupled with much lower plasticity precludes a prediction of its relative clinical efficacy.


A self-administered questionnaire--an aid in managing complete denture patients. A written self-administered questionnaire aids in treating edentulous patients and greatly reduces the possibility of patient dissatisfaction and medicolegal complications. Twenty-two questions have been presented which are to be answered in writing by the edentulous patient prior to the interview and examination. Such a questionnaire has several advantages31: (1) It saves time for the dentist and reduces the cost of treatment. (2) It quickly identifies problem areas. (3) It provides background information on the patient which is useful during the oral interview. (4) It identifies patients who write more intelligently and openly than they speak. (5) It evaluates neuromuscular coordination through handwriting review. (6) It serves as a reference for postinsertion problems. (7) It has legal merit when properly dated and signed and indicates that maximum diagnostic and therapeutic efforts are intended.


Etiologic factors in denture sore mouth syndrome. A total of 24 patients, 19 women and 5 men, complaining of denture sore mouth was studied. In part I the following investigations were performed: (1) Mechanical factors were evaluated. (2) Temperature was measured beneath the prosthetic denture. (3) Yeast cultures were made. (4) Patch tests with possible allergens were performed on the buccal mucosa and on the skin of the back. In all these investigations there were no significant differences from the results obtained in a control group. In part II the connection between psychological factors and denture sore mouth was explored. Test results of the denture sore mouth group and a matched control group were compared. The obtained data suggest that complaining behavior concerning somatic symptoms in general, on a neurotic base, is a psychological characteristic of denture sore mouth patients.


Computer-graphic representation of mandibular movements in three dimensions. Part II: the sagittal and frontal planes. Mandibular movements can be represented and viewed graphically in three planes--occlusal (approximately horizontal but variable), sagittoid (approximately sagittal), and frontal. The student of occlusion can vary the settings of the mathematical articulator and observe the three-dimensional changes produced in the interocclusal movement patterns.


A comparison of properties for zinc phosphate cements mixed on room temperature and frozen slabs. The following conclusions may be drawn from this study: 1. More powder may be incorporated into the cement liquid when the cement is mixed on a frozen slab rather than a room temperature slab. 2. A dramatic increase in the working time and decrease in setting time occur with frozen-slab mixes. 3. No statistically significant difference in compressive strength was found for the room temperature and frozen-slab mixes. 4. Solubility and disintegration values for room temperature and frozen-slab mixes of the three cements not containing fluoride were below the maximum limit of ADA Specification No. 8.


A method for assessing the clinical solubility and disintegration of luting cements. A test was designed for evaluating the distintegration of cementing agents in the oral cavity. The cements were placed in small holes located in the proximal surfaces of cast gold restorations so that the materials were not subject to abrasion. Each cement was placed in one hole located occlusally and one located gingivally. Four commercial cements of four different types (zinc phosphate, zinc silicophosphate, polycarboxylate, and EBA-Alumina zinc oxide/eugenol) were tested in 15 patients, and differences were observed in the deterioration rates of the different cements over the 6 month period. The disintegration rate of a given cement was the same in the gingival and occlusal positions. No correlation was observed between the clinical data on loss of material and the solubility of the cements as measured by conventional in vitro tests.


Microleakage of several amalgam systems: an animal study. Restorations placed without the application of cavity varnish to the cavity walls and the cavosurface angle exhibited significant marginal leakage after 24 hours and 3 months. At the end of 6 months a decrease in leakage was exhibited with all alloys. With the exception of two specimens, restorations placed after coating the cavity walls and the cavo-surface angle with cavity varnish demonstrated slight or no marginal leakage at all time intervals. The results of this study indicate that the marginal leakage of a conventional filing alloy, a conventional spherical alloy, and two high-copper alloys are approximately the same. The corrosion-resistant high-copper alloys showed the same degree of marginal leakage as the conventional alloys. The results of this study agree with those of a previously reported in vitro study on amalgam leakage.


Single-visit hollow obturators for edentulous patients. A method of fabricating a simple hollow obturator for edentulous patients was described. This procedure can be accomplished in a single office visit using readily available materials. The use of a relatively long-lasting soft reline material for obturators allows stable, comfortable, and effective obturation for many edentulous patients with recently created maxillary defects (Fig. 6). The hollow prosthesis is lightweight and sufficiently flexible to allow relatively simple placement in retentive undercut regions. Direct finger placement of the material insures complete duplication of all desired tissue undercuts. The soft reline material may also serve as a final impression of the defect when fabrication of the definitive prosthesis is undertaken.


Facial pains and anxiety levels: considerations for treatment. The data presented in this article question the traditional beliefs in the dental literature about the relationship between facial pain and anxiety. The findings have important implications for treating individuals with any of the IFP syndromes.


Myofascial pain-dysfunction syndrome.

Myofascial pain-dysfunction syndrome. Of the 127 patients treated for MPDS over a 30 month period, only six patients did not make at least a 90% recovery within 3 to 4 months. In most instances a spectacular degree of success was achieved within 2 to 3 weeks. Ten percent of the patients who were treated had had symptoms of the MPDS for a period longer than 5 years. These patients are usually more difficult to treat, and should receive extra attention. In patients with a long-standing history of MPDS it is advisable to apply all seven phases of treatment.


An evaluation of mandibular border movements: their character and significance. 1. A comparison of protrusive and lateral condylar border movement pathways of 163 subjects revealed considerable similarity when the frequency of 80% of the pathways was compared with the average pathway. 2. A description of the pathways of posterior cusps during lateral contact gliding movement must consider three simultaneously acting guidance factors: (1) the nonworking condyle pathway, (2) the amount of Bennett movement or the working-side condyle displacement, and (3) the anterior guidance or working-side tooth contacts. 3. A Bennett movement of 2.5 to 3.5 mm caused a dramatic flattening of lateral movement pathways of the molar cusp as seen in the frontal plane. The steepness of neither the anterior guidance nor the nonworking condylar pathway had much influence on the molar cusp pathway in the presence of this excessive Bennett movement. 4. Viewed in the horizontal plane, excessive Bennett movement contributed to the greatest potential for collisions of molar cusps during lateral movements. This phenomenon was more pronounced on the nonworking side. 5. When the Bennett movement was 0.75 mm or less the tracing in the frontal plane showed that the 40-degree anterior guidance became the dominant influence over molar cusp lateral movement pathways.


Clinical evaluation of cement solubility. This study evaluated a method of comparing the in vivo solubility of permanent luting cements. The cements were carried in crypts placed in complete dentures. A vented cover allowed for free access of fluids. Nine cements were evaluated, and cement loss was measured at 6 months. The glass ionomer (at two powder-liquid ratios) and silicophosphate cements demonstrated an approximately equal amount of solubility, which was less than for the other cements tested. The results of this study are in fairly close agreement with two previously published studies on the clinical solubility of cements.


Intraoral photographic survey.

Intraoral photographic survey. A standardized nine-view photographic survey is presented (Fig. 12). Equipment, position of patient and photographer, placement of mirror and retractors, and position of the light source are described. The interest in and value of photographic documentation has increased, and a standardized survey offers many legal, organizational, and educational advantages.


Occlusal splint fabrication.

Occlusal splint fabrication. Occlusal splints are useful in the treatment of occlusal and temporomandibular joint problems. Occasionally a patient is in a state of discomfort that requires immediate attention. This technique allows for the rapid and effective fabrication of an occlusal splint in the dental office.


Modifying tray materials to improve working qualities. A detergent solution incorporated to tray materials during their preparation period increases their plastic period and allows the necessary time for the making of well-adapted custom trays.


Dental assistant evaluation index: a technic to evaluate the work performance of Indian Health Service dental assistants. 1. The DAEI appears to be a useful instrument to evaluate dental assistant students in a reliable, uniform manner for the "core" dental assistant activities. 2. Calibration of the supervisors will be needed if the evaluation data are to be used on comparative bases from clinic to clinic or area to area. 3. Further study is needed to confirm the reliability and to establish the validity of the index. The current study should be considered an initial effort that should be continuously modified to maximize its usefulness. 4. Further study is needed to ascertain whether there is a real difference in the way dental auxiliaries view their job as compared to dentists. 5. Scores for dental assistants cannot be indiscriminately compared in a meaningful manner between auxiliaries at different locations. Even within a facility, caution should be applied before making conclusions based upon comparative scores. 6. The use of the DAEI for assessing the quality of the Dental Assistant Training Center was not adequately evaluated. The index may have this potential, but more study is required before it will be clear as to how the index might apply.


The inclusion of capitation reimbursement in solo practice. Capitation reimbursement has been an integral part of prepaid group practices in both medicine and dentistry, and claims have been made for its ability to influence the delivery of services favorably. Experts have suggested that if capitation is implemented, more preventive care will be provided, more diagnostic services will be provided, there will be better continuity of care, utilization of high-cost services will be reduced, and clinical outcome will be improved. This study focused on the dominant mode of practice in dentistry, the general, solo practitioner, to determine if these contentions held. A sample of 245 patients whose care was paid for by a capitation mechanism was matched to a sample of 245 similar patients whose care was paid for on a standard fee-for-service basis--all from three dentists' practices. All services in all years of care for each patient were analyzed. It was determined that the rate of restorations was lower, while rates of diagnostic testing and prophylaxis were higher for capitation patients. Continuity was also better under capitation, but rates of extractions were virtually identical for the two groups.


Geographic patterns of bladder cancer in the United States. Age-adjusted rates of mortality during 1950-69 from bladder cancer were correlated with demographic and industrial indexes for the 3,056 counties of the contiguous United States. Rates among whites and nonwhites of both sexes rose sharply with urbanization. A small but positive socioeconomic gradient was observed, and mortality was slightly higher among males in counties with high percentages of British and German residents. Even after controlling for demographic variables, the Northeastern excess of bladder cancer among whites was sizable, whereas the regional differences among nonwhites were small. The high rates in the Northeast were seen in both sexes and in rural as well as urban areas, with mortality in small counties in upstate New York and New England equaling or exceeding those in large metropolitan centers elsewhere in the country. Outside the Northeast, high rates were generally limited to urban areas, but clusters of elevated mortality occurred among white males along the Illinois-Wisconsin border, in parts of lower Michigan, and in southern Louisiana. Industrial factors may explain at least part of the geographic clustering, inasmuch as rates among males were significantly higher in U.S. counties where the chemical industry is heavily concentrated. Increases were also associated with the printing industry, but correlations with 16 other major manufacturing industries were near or below expected levels.


Increased risk of brain tumors in children exposed to barbiturates. The possible etiologic role of barbiturates in the development of brain tumors in children was examined. Interviews were conducted with mothers of children with brain tumors and results compared with those from interviews with mothers of normal children and mothers of children with other cancers. Mothers of children with brain tumors more frequently reported having used barbiturates during their pregnancy with the index child than did mothers of normal children or mothers of children with other cancers. In addition, more children with brain tumors were reported to have used barbiturates than were normal children or children with other malignant diseases, with most of such uses appearing to be unrelated to symptoms resulting from the brain tumor itself. The results suggested that barbiturates may play an etiologic role, and it is estimated that as many as 8% of brain tumors in children may be attributable to use of barbiturates either by the child or prenatally by the mother.


Cancer mortality and morbidity among rubber workers. Mortality and morbidity from cancer among a cohort of 13,570 white male rubber workers were examined. Each man worked for at least 5 years at the Akron, Ohio, plant of the B. F. Goodrich Company. The potential period of follow-up was from January 1, 1940 to June 30, 1976. Departmental work histories were based primarily on records maintained by Local no. 5, United Rubber Workers. The occurrence of cancer was measured by death certificates and by a survey of Akron-area hospital tumor registries from 1964 to 1974. Two types of analyses were made: 1) an external comparison of mortality rates of rubber workers versus rates of U.S. white males, and 2) an internal comparison of cancer morbidity rates among persons who were employed in various work areas of the plant. Excess cases of specific cancers (observed/expected numbers) among workers in specific work areas included: stomach and intestine: rubber making (30/14.4); lung: tire curing (31/14.1), fuel cells and/or deicers (46/29.1); bladder: chemical plant (6/2.4), and tire building (16/10.7); skin cancer: tire assembly (12/1.9); brain cancer: tire assembly (8/2.0); lymphatic cancer: tire building (8/3.2); and leukemia: calendering (8/2.2), tire curing (8/2.6), tire building (12/7.5), elevators (4/1.4), tubes (4/1.6), and rubber fabrics (4/1.1). Agents that may be responsible for these excesses were considered.


Relation between component parts of fibrocystic disease complex and breast cancer. Specimens of benign breast disease obtained from biopsies performed at Vanderbilt Hospital (Nashville, Tenn.) between 1952 and 1959 were histologically reviewed and characterized as to individual component types of fibrocystic disease. Follow-up for information regarding breast cancer development was 94% successful. Carcinoma developed more often when epithelial proliferative lesions were present. Atypical lobular hyperplasia had a greater predictive value than other epithelial lesions and was associated with an elevated risk six times that expected prior to the age of 45 years and a tripling of risk after the age of 45 years. Various ductal hyperplastic lesions are associated with approximately a doubly increased risk that is present only if the lesions are identified at biopsy after the age of 45 years. Women with cysts, sclerosing adenosis, fibrosis, and other nonhyperplastic changes were at no greater risk for subsequent carcinoma than women in the general population.


Cell-mediated responses in dogs with spontaneous neoplasms. I. Detection of cell-mediated cytotoxicity by the chromium-51 release assay. A series of 43 dogs with spontaneous melanomas, sarcomas, or mammary carcinomas were tested for peripheral blood lymphocytotoxicity against a range of allogeneic tumor cells in vitro on one or more occasions during therapy. All tumor-bearer groups contained a proportion of dogs showing a significant 51Cr release with increasing effector-to-target cell ratios. However, cytotoxicity was not restricted for target cells of the same histologic type as that of the effector cell donor. Some unrelated target cells more sensitive to nonspecific effects showed a greater cytotoxicity in some instances. Control effector cells from healthy dogs were nonspecifically cytotoxic for a range of tumor target cells in a similar proportion of instances. Short-term cultures of autochthonous tumor target cells were resistant to lysis in the 51Cr release assay. The findings did not provide evidence for the existence of specific tumor antigens operative to allogeneic 51Cr release cytotoxicity assays.


Cell-mediated responses in dogs with spontaneous neoplasms. II. Detection by direct leukocyte migration inhibition technique. A series of 39 dogs bearing spontaneous mammary carcinomas or melanomas were tested for tumor-directed immune response against allogeneic Formalin-treated tumor cells. The immune response was assessed by the direct leukocyte migration inhibition technique. Comparison of leukocytes from tumor bearers and healthy donors by chi-square analysis showed no statistical difference between the groups. The findings did not provide evidence for the existence of specific tumor antigens in the dog.


Degradation of cell-bound antibodies by tumor cells from C57BL/6 mice. A kinetic study of the disappearance of sensitizing antibody from metabolizing EL 4 cells in C57BL/6 mice revealed that this disappearance was at least partly due to the degradation of the antibody into dialyzable products. The degradation took place at 37 degrees C, but not at 4 degrees C, and occurred on or inside the cell. The process was specific inasmuch as only those IgG molecules that could bind to the cells were degraded, whereas unrelated third-party antibodies present in the culture medium remained intact. Although nonmalignant cells also have the capacity to degrade cell-bound antibodies, possibly the degradation of proteinaceous structures on antitumor effector mechanisms is, in part, responsible for decreased antitumor immunity.


Antibody-dependent lysis of tumor cells in vivo. I. Early lysis of tumor cells. Possible mechanisms of in vivo killing of tumor cells by antibody (Ab) were explored in a model in which Ab suppresses tumor growth in mice. A proportion of tumor cells injected into the peritoneal cavities of complement-deficient A/J mice was lysed within 30 minutes in the presence of anti-tumor cell Ab as demonstrated by the release of 51Cr in vivo. Experiments in which [125I]5-iodo-2'-deoxyuridine-labeled tumor cells were used showed that most tumor cells did not leave the injection site and that lysis occurred inside the peritoneal cavity. In addition, a proportion of the remaining sensitized tumor cells was significantly damaged, as shown by their decreased resistance to osmotic lysis. Morphologic studies ruled out phagocytosis of tumor cells as a mechanism of major significance. Tumor cell damage but not tumor cell lysis could also be induced in vitro with Ab and normal peritoneal cells. These results provided direct evidence of primary cytolysis induced by Ab in vivo, though other concomitant cytotoxic mechanisms may also take place in this model.


Effect of colostomy on intestinal carcinogenesis by methylazoxymethanol acetate in rats. The effect of the fecal stream on the induction of intestinal tumors was studied in 3 groups of SD rats. Rats in group 1 were subjected to single-barreled colostomies for the complete exclusion of the fecal stream at the proximal one-third level of the colons and were given consecutive iv injections of methylazoxymethanol acetate. Rats in group 2 were given methylazoxymethanol acetate alone. Rats in group 3 were not treated and served as controls. Tumors were noted in the small and large intestines of almost all rats in both groups 1 and 2. Even animals with single-barreled colostomies frequently developed tumors in the colon distal to the colostomy where the mucosa did not have contact with the fecal stream. These results indicated that carcinogens could probably reach the intestinal mucosa via the vascular system as well as by biliary transport.


[Acute myelogenous leukemia 11 years after successful treatment of Hodgkin's disease. A contribution to the problem of secondary tumors]. Acute myelogenous leukemia 11 years after successful treatment of Hodgkin's disease: A contribution to the problem of second malignancies. The occurence of a therapy resistant acute myelogenous leukemia 11 years after successful treatment (operation, radiotherapy, polychemotherapy) of Hodgkin's disease is described. While this second malignancy was rarely seen in the era of minimal or no therapy of Hodgkin's disease, it is nowadays described more often. The possible causes of this second malignant tumor are discussed. Although modern therapy of Hodgkin's disease should not be abandoned from fear of second malignancies, any change in primary treatment must consider not only acute toxicity but also the occurence of late second malignant tumors. Long term follow-up of all patients treated with radiotherapy and/or polychemotherapy is necessary.


The management of hyperkinetic children: a trial of dietary therapy. The standard techniques in the management of hyperkinetic children are not uniformly successful. Recently, there has been considerable interest in dietary therapy. The diet, low in artificial colours, and flavours and in naturally occurring salicylates has been adapted for use in New Zealand. Ten hyperkinetic children have been treated with the diet, five of whom improved dramatically and are now off all other therapy. Their response to accidental and deliberate challenge supports the hypothesis that the dietary regime described has been responsible for their improvement.


Clinical use of cefoxitin, a new semisynthetic cephamycin. Cefoxitin, a new semi-synthetic cephamycin, has been studied in the treatment of patients with a variety of infections. Included have been a number of patients who have impaired renal function. The drug proved to be effective in treating gram-positive, gram-negative and anaerobic infections, and can be given by the intravenous or intramuscular route. Adverse effects occurred in six of 34 patients. These were not usually serious. The presence of renal failure did not interfere significantly with the efficacy of cefoxitin in treating urinary tract infection and it is considered, in contrast to the aminoglycosides, that this preparation can be used successfully without the necessity for measuring blood or urine levels in patients with reduced or unknown renal function.


[Testing the hemalog D in a hematology department of a general hospital in Paris (author's transl)]. Europe's firs Hemalog D was installed in the Hematology Laboratory of the Franco-Musulman Hospital at Bobigny, just outside Paris, in March 1975. The authors' experience with the apparatus since that date has enabled them to analyze the significance of "alarms", "high peroxidase", "large unstained cells", "remainder" and "low rate" in patients with and without hematologic disorders. On the basis of these results it has been possible to define the fate of the various blood cells in the Hemalog D, the role of the apparatus in the ivestigation of hematologic disorders and the type of "cooperation" between the hematologist and the Hemalog D.


The significance of leukemic cell volume distribution. The use of electronic pulse spectroscopy to determine the volume distribution of a white blood cell fraction isolated by sedimentation from anticoagulated whole blood permits a rapid quantitative measure of size and dispersion of white blood cells in suspension. In patients without apparent hematologic diseases the white cell volume distribution presents as a broad peak. In patients with a large percentage of circulatory malignant cells, a single narrow volume peak is observed in acute leukemias and a broad and sometimes bimodal curve is observed in chronic leukemias. The volume of the leukemic cells is observed to shift in vivo after the start of effective chemotherapy as was predicted on the basis of a tissue culture model. The prognostic significance of the white cell volume distribution in leukemia and the use of a shift in size of leukemic cells after the start of therapy as a means of monitoring therapy are discussed.


Dose-response curves and competing risks. Points of the underlying dose-response curve of a lethal response or group of lethal responses induced by varying doses of a toxicant in a homogeneous population can be estimated from knowledge of the time of occurrence for all responses if the response(s) of interest is (are) statistically independent from the other competing responses (risks). In the case of statistical dependence, only tight upper and lower bounds can be established within which the points of the dose-response curve have to lie. These bounds for the response(s) of interest are far apart if the frequency of occurrence of the competing response(s) is large. In such situations, the shape of the underlying dose-response curve is only suggested by the imaginary band connecting the estimated bounds. The estimation procedures for both cases are illustrated with data from an experiment in which beagles received injections of 239Pu.


Some implications of an alternative structure for DNA. We have constructed a space-filling (Corey-Pauling-Koltun) model of an alternative structure for DNA. This structure is not a double helix, but consists of a pair of polynucleotide strands lying side by side and held together by Watson-Crick base pairing. Each of the two strands has alternating right- and left-handed helical segments approximately five base pairs in length. Sugar residues in alternating segments along a strand point in opposite directions. A structure slightly different from the present one proposed earlier by ourselves and another group and in which sugars in a strand all point in the same direction is ruled out. The present structure yields natural solutions to the problems of supercoiling of DNA and of strand separation during DNA replication. This model is energetically more favorable than the double helix.


Sterol requirement of Mycoplasma capricolum. Mycoplasmas require an external source of sterol for growth. For Mycoplasma capricolum this requirement is met not only by cholesterol but also by the methylcholestane derivatives lanosterol, cycloartenol, 4,4-dimethylcholesterol, and 4beta-methylcholestanol. Cholesteryl methyl ether and 3alpha-methylcholestanol serve equally well as sterol supplements. None of the growth-supporting sterol derivatives tested was metabolically modified. The unusual acceptance of diverse cholestane derivatives by a mycoplasma species contrasts with the structural attributes thought to be necessary for sterol function in eukaryotic membranes.


Inhibition of protein synthesis initiation by oxidized glutathione: activation of a protein kinase that phosphorylates the alpha subunit of eukaryotic initiation factor 2. Oxidized glutathione (GSSG) (0.02-0.5 mM) inhibits reticulocyte lysates by a mechanism similar to that observed in heme deficiency. Incubation of hemin-supplemented postribosomal supernates with GSSG results in the activation of a translational inhibitor [I(GSSG)]. The activation of I(GSSG) is enhanced by the presence of an energy-regenerating system. The simultaneous addition of 1 mM dithiothreitol blocks the activation of the GSSG-induced inhibitor; however, once inhibitor is formed, its activity is not affected by 1 mM dithiothreitol. GSSG-treated postribosomal supernates and partially purified preparations of I(GSSG) inhibit protein synthesis in hemin-supplemented lysates with biphasic kinetics. Inhibition by I(GSSG) is blocked by cyclic AMP (2-10 mM) and is potentiated by ATP (2 mM). The inhibition is also blocked or reversed by eukaryotic initiation factor eIF-2. The activation of I(GSSG) is accompanied by an increased cyclic AMP-independent protein kinase activity which phosphorylates the 38,000-dalton component (alpha subunit) of eIF-2; however, GSSG treatment of supernates does not alter the activity of the cyclic AMP-independent protein kinase activity that phosphorylates the 49,000-dalton polypeptide component (beta subunit) of eIF-2. These data indicate that GSSG treatment of reticulocyte lysates results in the activation of a protein kinase with inhibitory and phosphorylation properties similar to those of the heme-regulated cyclic AMP-independent protein kinase which is activated in heme deficiency.