Estimation of assortative mating preferences in the Arctic skua.

Methods are described for the maximum likelihood estimation of mating preferences in models of assortative mating for monogamous and polygamous organisms. These methods are applied to data of matings of the three phenotypes, pale, intermediated and dark of the Arctic Skua. The data were obtained by exhaustive surveys of the Arctic Skua populations on the islands of Fair Isle and Foula. The data give evidence of significant assortative mating of pale birds on Foula and intermediate birds on Fair Isle. The combined data show that there is very highly significant assortative mating, but only of intermediates. In previous surveys, data, in which intermediates and darks were not distinguished, were obtained from a number of islands in the Shetlands. These data, combined with the present data, show that the overall assortative mating of pale is very highly significant with no evidience of heterogeneity. The assortative mating of intermediate birds on Fair Isle agrees with other evidence showing that inermediate males have an advantage as a result of sexual selection.


Pluronic polyols in human lymphocyte cell line cultures.

Pluronic polyols markedly improved the growth of two human lymphocyte cell lines when added to the growth medium in concentrations of 0.05 to 0.1%. The results of the current studies suggest that, in addition to the protective effect of polyols against mechanical damage of mammalian cells in submerged cultures, the pluronic compounds may also, by lowering surface tension, facilitate transport of metabolites into cells and thus increase the growth rate.


Kinetics of crystal growth and dissolution of calcium and magnesium fluorides.

Kinetic results of the crystal growth and dissolution of seed crystals of calcium fluoride and magnesium fluoride, obtained conductimetrically and potentiometrically, indicate that both processes are controlled by a surface reaction mechanism. An initial reaction surge in the case of magnesium fluoride is consistent with a concomitant secondary nucleation process. The activation energies for the growth and dissolution of calcium fluoride, 14.5 and 1.4 kcal mole-1, also point to surface reaction control. The heat of solution of this salt, obtained calorimetrically, was 2.9 +/- 0.1 kcal mole-1.


Rheology of fluoride gels.

A number of fluoride gels containing a hydroxyalkyl cellulose thickening agent show non-Newtonian rheological behavior in the form of stress thinning (apparent viscosity decreasing with shear rate). Viscosities of 450 to 780 poise at low rates of shear down to 1.0 to 2.0 poise at high rates of shear were obtained. The effect of temperature on viscosity was comparatively small. One gel, containing a noncellulosic thickening agent showed a much more pronounced stress thinning (7,500 poise at low rates). Furthermore, at low rates of shear this material showed pronounced elastic behavior. This may well be clinically advantageous.


Preliminary report on effect of topical applications of titanium tetrafluoride on dental caries.

An annual, one-minute application of a 1% solution of titanium tetrafluoride to the teeth on one side of the mouth of each of 110 children offered greater protection against caries after three years than was given to teeth on the other side of the mouth treated with a four-minute application of acid phosphate fluoride.


A model for the study of development processes in dental research.

In studying growth and developmental processes in dental research, variables other than simple chronological age must often be taken into account if we are to adequately characterize differences in the developmental patterns of the groups under consideration. As demonstrated in this article, cohort, time-of-measurement, and learning (testing) effects may significantly interfere with our ability to directly study development if the traditional cross-sectional and longitudinal designs are used. Mixed-longitudinal studies, with well-scheduled control groups, may better serve the dental research community in the design of studies dealing with the measurement of change.


Inability of low levels of sorbitol and mannitol to support caries activity in rats.

Under the environmental conditions of these experiments, neither 5 nor 10% sorbitol or mannitol in diets containing 62 or 57% corn starch, respectively, was capable of increasing the caries activity in rats above the level supported by a 67% starch diet. In contrast, 5% sucrose in the presence of 62% corn starch caused a slight increase and 10% sucrose in the presence of 57% starch caused a significant increase in caries activity beyond that observed when the diet containing 67% starch as the only carbohydrate was fed.


In vivo effects of direct current in the mandible.

The application of low level direct current (3 to 5 mua in situ, that is, 50 mua/cm2), within the mandible of mature Beagle dogs results in an increased osteogenesis at the cathode (negative electrode) when compared to responses about nonactive (control) packs within the same dog. The increased osteogenesis suggests a stimulation of cellular activity rather than the electrophoretic migration of cells. Significant differences observed between platinum-iridium and stainless-steel electrodes seem to suggest that faradaic results play little or no role in the osteogenic response at the platinum-iridium cathode. Conversely, at all other electrodes, faradaic reactions compete to some extent with an osteogenic response. Careful consideration of current density and electrode composition must be taken into account when direct current stimulation is to be used.


Caseinolytic and glyoprotein hydrolase activity of Streptococcus mutans.

Proteolytic hydrolysis of casein and porcine or bovine glycoproteins by S mutans was demonstrated in the present study. Caseinolytic activity was found in both the soluble contents of the cells and the cellular debris after rupture of the cells. However, caseinolytic activity could not be demonstrated after growth in the culture fluid from any of the strains of S mutans tested. The soluble fractions of S mutans did not possess glycoprotein hydrolase activity toward porcine or bovine glycoprotein, but glycoprotein hydrolase activity was present in both the cell-debris preparation from cells and in the culture fluid after growth of the cultures. Based on these observations, S mutans may possess several different types of proteinase enzymes with differing specificities for protein substrates.


Delineation of somatic nerve endings in rat teeth by radioautography of axon-transported protein.

We have shown that there is extensive innervation of cusp pulp and dentin in rat molars. The dental nerves either end freely below the odontoblast layer or form gap junction endings on the odontobast cell body or along its dential process. The nerves are largely absent from response dentin, are found in contact with virtually all other odontoblasts at the tip of the cusps, are less frequent in intercuspal regions, and are absent from root dentin and odontoblast layers. The incisors were completely different from the molars, perhaps because they are continuously erupting teeth. The distribution of nerve endings in rat molars may be representative of that in teeth of other species, but the nerve endings should be mapped radioautographically for each type of tooth before generalizations can be made.


Effects of titanium tetrafluoride on human enamel.

Acid etch biopsy specimens of human enamel surfaces treated with a TiF4 solution have shown fluoride uptake to be significantly greater than in untreated surfaces, but less than that obtained with an APF solution of the same fluoride concentration. The TiF4 treated surfaces, however, do show a statistically significant reduction in the acid solubility of the enamel. The presence of acid-resistant coating was shown by SEM.


Surface failure of commercial and experimental restorative resins.

A single-pass test was used to study the surface failure of commercial and experimental restorative resins and composites. The surface failure observed for unfilled diacrylate resins was more severe than that seen for an unfilled acrylic resin. Addition of nonsilanated filler to the diacrylate resins increased the resistance to penetration but did not dramatically change the mode of surface failure. The surface failure of the commercial composite resins, which contain silanated filler, was ductile in mode and the resistance to penetration of the diamond slider was the highest of the materials studied. The wear of restorative resins and composites is determined, therefore, by resistance to penetration as well as mode of deformation during sliding.


Radioautographic study of mesenchymal cell activity in the secondary palate of the rat.

In this radioautographic study of the developing secondary palate of the rat, it has been shown that there was not the increased nuclear labeling indicative of increased mitotic activity in the mesenchyme said to be responsible for medial rotation of the palatal shelves. Variations in labeling index in different regions of the developing palate appeared mainly because of developing bone and mucous glands.


Thermal diffusion through amalgam and cement base: comparison of in vitro and in vivo measurements.

Thermal diffusion was measured in vitro and in vivo through amalgam and amalgam underlaid with bases of zinc phosphate, zinc oxide-eugenol, and calcium hydroxide cements. Although the magnitudes differed, there generally was good agreement between in vitro and in vivo data with respect to the relative rates of thermal diffusivity through amalgam restorations underlaid with bases of each of the three materials. In all tests, both in vitro and in vivo, the zinc oxide-eugenol base proved to be the best thermal insulator. Calcium hydroxide was the next best thermal barrier and was followed by zinc phosphate cement. In vitro tests indicated dentin to be a better thermal insulator than zinc phosphate cement but inferior to the zinc oxide-eugenol and calcium hydroxide base materials used here. Although a method has been presented here for the in vivo assessment of the efficacy of thermal insulating bases and a number of in vivo experiments were conducted, much research remains to be done in this area. Additional investigation is needed to better define the parameters of thermal change beneath various types of restoratives and also to establish more exactly the role of base thickness in providing thermal protection beneath clinical metallic restorations.


Characterization of cross-linked two-phase acrylic polymers.

A cross-linked network was formed in the particulate disperse phase carried over from the soluble pearls only in one material tested (L). The preparation of this material involved a slow rate of polymerization that allowed sufficient time for imbibition of the cross-linking monomer by the particles. In two of the materials (CR and S), the particulate phase was extractable and the remaining cross-linked matrix could be characterized for equilibrium swelling by volumetric measurements. Equilibrium swelling values were used to estimate densities of elastically effective chains in the network.


Eruption rates of human upper third molars.

Human maxillary third molars have been observed to have maximum rates of eruption of approximately 1 mm/2 mo. Rates of less than 1 mm/6 mo have also been recorded. Maximum rates of eruption were associated with spacing of the dentition. Passive eruption in the form of gingival recession is an important factor resulting in the exposure of the clinical crown.


Lidocaine's influence on brain amines in mice.

This series of experiments suggests that a relationship exists between convulsive doses of lidocaine and central depletion of 5-HT and DA. Since DA and usually 5-HT are regarded as central inhibitory transmitters, this study further supports the postulate that lidocaine's convulsive activity is by inhibition of central inhibitory pathways-possibly a dopaminergic or tryptaminergic pathway or both.


Observations on calcium-induced stability of salivary proteins in a lipid-extraction system.

The system described for investigating the effects of small ions on macromolecules of saliva may be applied to other solutions and is amenable to manipulation in order to obtain more specific information. Studies using aqueous solutions of saliva fractions previously separated by gel filtration are being conducted with C/M solutions containing various bivalent cation chloride salts. Preliminary results from these current studies have demonstrated that when the proteins are stabilized they vary as a function of the cation used.


Selection of an experimental unit in rat caries studies.

In two separate experiments, none of the 14 subunits examined consistently ranked dentifrices similarly to the ranking obtained when the individual rat was used as the experimental unit. Arbitrarily dividing the rat into subunits and then comparing results among these subunits may lead to false conclusions since the rankings using subunits vary within each experiment and from experiment to experiment.


Study of in vivo plaque formation.

The technique of accumulating plaque on removable disks in a complete denture provides a convenient method for investigating plaque on artificial surfaces. Examination of the plaque specimen with a SEM indicated that the plaque consists of microorganisms and a nonstructured matrix. This technique provides results that are consistent for a given individual. However, a group of 12 different individuals had a wide range in the thickness and content of plaque accumulations during equal time intervals. Thin plaque accumulations consisted of a filmlike layer with an apparently small number of microorganisms. Thick layers of plaque consisted of relatively large numbers of microorganisms with some intercellular matrix. The thickness of the plaque layer is apparently determined primarily by the number of microorganisms present.


Reactions in glass-ionomer cements: IV. Effect of chelating comonomers on setting behavior.

The oscillating rheometer is a valuable instrument for studying the effects of additives on the setting behavior of a cement system. Using this instrument, it was found that certain chelating comonomers, the hydroxycarboxylic acids, could improve the setting characteristics of the glass-ionomer cement system when added to the PAA solution. The acid chelates probably assign the extraction of metal ions from the glass and also tend to hold them in solution, preventing premature ion binding of the polyanion chains. The effect is to increase the rate of hardening without reducing the working time, which may indeed by slightly increased. Tartaric acid, the most effective of the comonomers, can form a chelate bridge between aluminum atoms, and this metal complex probably acts as a flexible bridge structure linking polyanion chains. This mechanism offers some steric advantages over a simple salt bridge.


Kinetics and mechanism of hydroxyapatite crystal dissolution in weak acid buffers using the rotating disk method.

The model given in this report and the rotating disk method provide a useful combination in the study of dental enamel and hydroxyapatite dissolution kinetics. The present approach is a significant improvement over earlier studies, and both the ionic activity product that governs the dissolution reaction and the apparent surface dissolution reaction rate constant may be simultaneously obtained. Thus, these investigations have established the baseline for the dissolution rate studies under sink conditions. Concurrent studies, under conditions where the acidic buffer mediums are partially saturated with respect to hydroxyapatite have shown another dissolution site for hydroxyapatite that operates at a higher ionic activity product but has a much smaller apparent surface reaction rate constant. This has raised the question of whether the presence of this second site may interfere with the proper theoretical analysis of the experimental results obtained under sink conditions. A preliminary analysis of the two-site model has shown that the dissolution kinetics of hydroxyapatite under sink conditions is almost completely governed by the sink condition site (KHAP = 10(-124.5), k' = 174) established in this report. The difference between the predicted dissolution rate for the one-site model and the two-site model are generally of the order of 4 to 5% where the experiments are conducted under sink conditions and over the range of variables covered in the present study.


Fluoride in human parotid saliva.

Gustatory stimulation was used to collect parotid saliva in an ascending flow rate pattern. F concentration was found to be independent of rate of flow. The F level in unstimulated parotid saliva, collected before the stimulate samplings, was significantly (P less than 0.01) higher than that for the stimulated collections. It is suggested that this is an apparent increase based on the movement of water out of the lumen, which is in turn triggered by sodium reabsorption. The level of F in unstimulated saliva increased almost tenfold within one hour after the oral administration of 10 mg of F, and a significant (P less than 0.01) increase persisted even at 24 hours after administration of the dosage.


Comparison of personal values among freshman and senior dental students and dental faculty.

The purpose of this study was to test the effects of dental education on the values of dental students and dental faculty. This was accomplished by testing five hypotheses. The results of the study indicate no significant differences between freshmen and senior students' values; infer no apparent changes in student values during a dental education; indicate no significant differences between part-time faculty and full-time faculty; support a positive association among all groups, i.e., freshmen, seniors, full- and part-time faculty; rank-order the values for all groups from highest to lowest (theoretical, aesthetic, political, economic, social, and religious); and show some significant differences between students as a group and faculty as a group. If a more objective means of choosing dental students is desired, then further research will be needed to determine the characteristics of the type of practitioner that is needed. The presented data help in defining one aspect of the collective personality of dental students and dental faculties.


Undergraduate grades, class standings, and performance in a graduate orthodontics curriculum.

This study shows that graduate performance correlates poorly with undergraduate class standing; that relatively large differences in class standing are not generally accompanied by correspondingly large differences in grade point average; and that performance in just ten courses, taken in the freshman and sophomores years, predicts, with a multiple correlation coefficient of 0.88, the final undergraduate class ranking of a student. It is argued that variables other than class rank should receive more weight in the selection of graduate dental students. Undergraduate orthodontics courses made no significant contribution to this prediction. These factors, when combined with a failure to include other relevant factors in selecting graduate students (in particular, the failure to take into account any postgraduate clinical experience), explain the low correlation between undergraduate class rank and performance in the graduate orthodontics program. It is suggested therefore that factors other than undergraduate class rank receive considerably more weight in the selection process.


Improving evaluation of amalgam restorations.

A predictive model of overall quality of performance is presented which might assist both dental students and dental faculty by increasing the reliability of clinical and laboratory evaluations. Training effectiveness can be improved by identification of those restorative skills which contribute most to the quality rating of restoration.


Methods for analysis of acid alpha-1,4-glucosidase activity in single hybrid cells.

Two methods are described which allow the quantitative assay of the lysosomal enzyme alpha-1,4-glucosidase in single fibroblasts. In the first procedure the substrate was maltose, and liberated glucose was measured with an enzymatic cycling procedure for reduced nicotinamide adenine dinucleotide phosphate. Single cultured fibroblasts were found to have enzyme activities in the range of 0.5-10 X 10(-13) moles glucose/hr. In the second procedure the artificial substrate 4-methylumbelliferyl-alpha-D-glucopyransodie was used. It is hydrolyzed in a single step reaction to the fluorescent product 4-methylumbelliferone (MU). By reducing the incubation volume and by measuring the fluorescence in microdroplets with a microscope fluorometer, a sensitivity of 10(-14) moles MU could be obtained. Activities were found ranging from 0.5-10 X 10(-14) moles MU/hr/cell. Both procedures for single cell analysis proved to be reliable when compared with conventional assays on cell homogenates. Cocultivation and cell fusion studies were performed to demonstrate that these methods can be used to study the metabolic and genetic interaction between normal and enzyme-deficient fibroblasts derived from patients with glycogenosis II.


Cardiorespiratory effects of a balanced anesthetic technique in outpatient general anesthesia.

Detailed measures have been made of the cardiorespiratory effects of a balanced general anesthetic technique on ten young patients undergoing oral surgery. The combination of fentanyl, diazepam, and atropine followed by N2O/O2 and methohexital resulted in a respiratory hyperoxic state throughout surgery and there was no evidence of hypercardia at any anesthesia stage. Cardiovascular stability was judged to be generally superior to that reported for techniques that have relied on methohexital without premedication. This balanced general anesthetic technique offers the oral surgeon-anesthetist a safe, effective, and practical alternative to techniques that rely on more potent anesthetic gases.


Evaluation of a microcrystalline collagen preparation in extraction wounds.

The microcrystalline collagen preparation evaluated in this study appeared to create a slightly denser and longer lasting inflammation and to delay slightly the early phase of bone repair in this wound model. However, beneficial effects of more rapid achievement of hemostatis were also noted. On the basis of these findings, it would be of interest to compare this material with other more widely used materials, such as gelatin foam, in this wound model.


Analgesic requirements after orthognathic surgery.

Postoperative analgesic requirements of a series of 45 patients who underwent orthognathic surgery are presented. Of the first 25 patients treated before a minimal analgesic protocol was begun, 21 received narcotic medication for relief of discomfort. In the second group of 20 patients, five received mild analgesics and one received a narcotic. A combination of factors such as paresthesia, immobilization, premedication, steroids, and residual effects of general anesthetic agents probably contributed to the relative lack of severe pain after orthognathic surgery.


Aberrant conduction as a precursor to cardiac arrhythmias during anesthesia for oral surgery.

In 109 patients, it was determined that halothane, when used to anesthetize patients for oral surgical procedures, causes an increased risk of serious cardiac arrhythmias when compared to methoxyflurane and fentanyl/droperidol. It is postulated that this is due to halothane's ability to decrease cardiac conduction and to facilitate the development of reentry phenomena. This decreased conduction may be accentuated by vagal efferent reflexes that have the same effect. The decrease in cardiac conduction was manifested by an ECG pattern of aberrant conduction. This phenomenon was not noted with either methoxyflurane or fentanyl/droperidol.


Outpatient treatment of hemophiliacs for dental extractions.

The outpatient treatment program for dental extraction in persons with the various forms of hemophilia has been reported. This program was initiated at the Hemophilia Rehabilitation Center at Orthopaedic Hospital in Los Angeles in 1966. During the nine years of this program, 260 patients have had 642 teeth extracted. eighty percent of these patients were outpatients and 64% of the extractions were performed on an outpatient basis. This outpatient treatment has been accompanied by an absence of a significant number of complications as evidenced by the postextraction hospitalization of only five patients during the nine-year period. The surgical technique uses a local anesthetic containing a vasoconstrictor or an ultralight intravenous general anesthetic in addition to the local anesthetic for the apprehensive or acutely infected patient. EACA is used as an antifibrinolytic agent postsurgically. Patient education and cooperation, diet control, and daily contact are important factors for the success of an outpatient oral surgery program for hemophilic patients.


Treatment of fractures of the zygomatic bone.

Various methods of treatment used for 70 patients with complex fractures of the zygomatic bone are reviewed. It was established that adequate fixation of most instances of rotated tripodal fractures can be accomplished with use of a zygomaticofrontal wire supplemented by an intrasinus Foley catheter.


Ludwig's angina due to bacteroides.

This case presentation concerns a 21-year-old Negro man in whom Ludwig's angina developed after a dental infection. The many serious complications encountered with such an infection are described in some detail. The involvement of anaerobic Bacteroides in infections of the head and neck is also noted and the approach to treatment is described.


The use of silk for maxillomandibular fixation.

A method of maxillomandibular fixation for jaw fractures that uses silk ligatures has been described. After the period of muscle spasm has been overcome by maxillomandibular elastics, these are replaced with the silk suture material. Silk prevents the occurrence of hypertrophy of the buccal mucosa that is occasionally seen with the use of elastics. Also, patient comfort is improved by minimizing the pull on the teeth and facilitating better oral hygiene in the postoperative period.


Anterior and posterior lingual depressions of the mandible.

Both posterior and anterior lingual depressions occur in the mandible. The posterior lingual mandibular depressions appear to be more common than had been previously reported. This probably due to one or both of the following causes. Shallow lesions are difficult to diagnose radiographically since an appreciable depth of lingual cortical plate must be resorbed before they can be visualized. As these may be active lesions, a slow resorptive process could place the patient into middle age or beyond before the lesion is clinically diagnosed. It is suggested that posterior lingual mandibular depressions may be benign, self-limiting lesions that are caused by a slow resorptive process resulting from pressure of unknown origin. The anterior lingual mandibular depressions are variable findings in dried mandibles that appear grossly as round or oval smooth depressions with intact buccal and lingual cortical plates and, radiographically, as ill-defined radiolucent areas with no radiopaque borders. They are usually located in the incisor-lateral-canine area and are usually bilateral. It is suggested that these depressions may be developmental anomalies related to the buttons of Gaughran or that they may simply be anatomic variants. They differ from posterior depressions in both gross and radiographic appearance, which suggests the existence of two distinct entities.


Indications for antibiotics in orthognathic surgery.

One hundred forty-eight cases of orthognathic surgery were evaluated for incidence of infection; 68 had antibiotic prophylaxis and 80 did not. Only three instances of infection occurred, all in the group that had received antibiotics. Results of this study disprove the necessity for routine prophylactic use of antibiotics in most types of orthognathic surgery.


The intraoral inverted-L double-oblique osteotomy of the mandibular ramus: a new technique for correction of mandibular prognathism.

Use of a new technique for correction of mandibular prognathism has resulted in reduction of operating time, less loss of blood, and minimal change in muscle relationships. Wiring of the fragments and use of pressure dressing are unnecessary; edema is minimal.


Technique for primary closure of infected wounds of the orofacial region.

A technique for successful immediate primary closure of long-standing, neglected, or infected wounds of the orofacial region has been described. Functional and esthetic results have been gratifying with the need for secondary revision generally obviated.


Intraoral papillary cystadenoma lymphomatosum.

The literature related to intraoral papillary cystadenoma lymphomatosum is critically reviewed and the reported cases analyzed to determine the average age, sex, and race of patients, and the site distribution of this curious lesion. Two new cases are reported. The histogenesis and differential diagnosis from cystadenocarcinoma are briefly discussed.


Fluid therapy in the critically injured patient.

Sufficient clotting factors to ensure coagulation and replacement of lost volume and oxygen-carrying capacity are necessary to obviate many of the complications that may occur when massive transfusions are used in patients with multiple injuries. A regimen that has been successful includes immediate infusion of plasma protein fraction, packed red cells, fresh-frozen plasma, and nonspecific platelets.


Cut-down sialography of the submandibular gland.

Sialography of the submandibular gland which is often deferred because of inability to isolate, dilate, and cannulate Wharton's duct, can be safely accomplished with minimal morbidity with use of a modification of the surgical procedure to remove a salivary ductal calculus. It can be accomplished as an office procedure in ambulatory patients.


Use of Kirschner wires for securing acrylic splints to the maxilla.

A technique is described for securing a splint to the maxilla in instances where there is adequate alveolar bone without having to use circumzygomatic or nasal wiring.


Congenital micrognathia and partial adactylia.

A case of micrognathia and partial adactylia is presented. Several syndromes that can be classified under the term oral-mandibular-limb dysgenesis are discussed, as well as a report of a patient with malformations corresponding closely to the malformations seen in our patient. Genetic and environmental causes of micrognathia are discussed in conjunction with the various theories of the mechanism of congential oral deformities. Finally, a surgical approach to the correction of micrognathia is presented with postoperative results.


Structure of the microbial flora associated with periodontal health and disease in man. A light and electron microscopic study.

Teeth slated for extraction were evaluated with respect to their periodontal status and classified accordingly into five categories; namely normal, gingivitis, periodontitis, periodontosis and postperiodontosis. After processing, one approximal surface of each tooth was sampled at various levels in an apico-occlusal direction for light and electron microscopic study of the associated bacterial flora. In normal samples, the flora consisted of a relatively thin, adherent bacterial layer confined to the enamel surface. The cells were predominantly coccoid in shape with cell wall features compatible with those of Gram-positive organisms. Isolated filamentous or branching forms and some Gram-negative bacteria were noted on the surface of the more apical portion of the bacterial layer. No flagellated cells or spirochetes were present. Gingivitis samples yielded a relatively more voluminous and complex supragingival flora with relatively more filamentous bacteria and more cells with a Gram-negative cell wall ultrastructure. These samples also contained corncob formations on the surface of supragingival deposits, and flagellated cells with spirochetes within the predominantly Gram-negative flora of the sulcus bottom. Supragingival bacterial deposits of periodontitis samples were similar to those observed in gingivitis. The subgingival flora consisted of relatively fewer cells adherent to the root surface with a concomitant increase in the population of Gram-negative and flagellated cells, as well as spirochetes. The tissue side of the subgingival flora generally exhibited a distinctive concentration of "test-tube brush" formations, spirochetes of predominantly medium size, and assorted cell types peculiar to this region. A transitional flora generally separated the supra- from the subgingival microbial population. Periodontosis samples had a relatively sparse, predominantly Gram-negative flora. A unique electron-dense, lobulated cuticular deposit covered the majority of the samples studied. Postperiodontosis samples were much more similar in their microbial flora to the periodontitis group. The results suggest that (1) a certain microbial flora may be compatible with a state of periodontal health; (2) a different flora is associated with varying degrees of periodontal disease; (3) the structure and composition of the supragingival flora differs markedly from that of the subgingival flora; (4) with the exception of periodontis, the alterations of the microbial flora as periodontal disease increases inseverity parallel the changes described previously in the microbial population collected on artificial crowns during experimentally induced gingivitis. The use of the expressions "microbial flora" or "microbial population" is considered preferable to the terms "plaque", "materia alba", or "debris" in reference to the microbiota of the gingival sulcus region.


The use of blade implants in a selected population of partially edentulous adults. A five-year report.

Based on the findings observed after the insertion of 33 blade implants in 23 patients, ages 31 to 74, for periods up to 60 months, the following conclusions can be made: (1) The blade implant is a technically feasible procedure which can be maintained in the mouth for period up to 5 years, although some degree of bony breakdown will be seen in a majority of the patients at this time; (2) The degree of breakdown around blade implants is almost exclusively located to the locus of the neck of the implant and is most likely due to the lack of attachment at the epithelial-implant interface.


Histologic features of the superior labial frenum.

Histologic examination was performed on the superior labial frenum obtained from 11 fresh biopsy and three autopsy specimens. The frena contained considerable dense collagen, loose connective tissue and elastic fibers. There were no muscle fibers in any of the frenum sections except the autopsy specimens, where it was seen in the vestibular tissue but not in the frenum proper.


Psoriasis of the attached gingiva. Case report.

Psoriasis of the gingiva is a rarely diagnosed disease entity. A case is presented with both clinical and histologic documentation that fulfills all basic criteria. It is suggested that oral psoriasis does not contraindicate periodontal or prosthetic management.


Periodontal disease associated with preleukemic syndrome.

A case of preleukemic syndrome associated with severe periodontal disease has been presented for the first time. The clinical, radiographic and hematologic findings have been discussed, as well as medical and periodontal therapy.


Forced eruption: part II. A method of treating nonrestorable teeth--Periodontal and restorative considerations.

In selected cases, forced eruption may be a useful approach in treating isolated nonrestorable teeth as a result of trauma, caries, or iatrogenic dentistry. This paper has presented the biologic rationale, objectives, technics and clinical cases to demonstrate the principle. Evaluation has been made of potential difficulties which may develop with the technic and areas for future research have been identified.


Rebuilding of microvascularization following surgical gingival elimination by split flap. Study by perfusion and diaphanization.

1. Intra-arterial vital perfusion was used in dogs to study the rebuilding of the large amount of gingiva and its vascularization, which were removed surgically by split flaps. 2. Visualization of the reconstruction of the microvascularization could be observed through thick (400 mu) sections cleared in methyl salicylate. 3. The periosteal vessels and the vascular plexi of the dentogingival junction were the only vessels remaining after the surgery, and served as progenitors for the rebuilding of the vascularization of the new soft tissue complex. 4. After 48 hours the cut vessels were closed and new capillaries were beginning to form. An intense superficial vascularization was connected by multiple vessels to the periosteal vasculature (4 days), showing the largest number of superficial blood vessels after 7 days, when the area was primarily re-epithelialized.


Mast cell distribution in oral tissues of germ-free vs. conventional beagle dogs.

Light microscopic examination of the mast cell distribution in various oral tissues in germ-free and conventional beagle dogs revealed no differences between the two animals. Mast cells were observed in all tissues examined, with an increasing order of incidence as follows: cervical lymph node, parotid and submandibular glands, marginal gingivae, buccal mucosa and the middle one-third of the tongue. All four types (round, oval, elongated, and pseudopodial) of mast cells cell shapes previously described in the literature were observed. The marginal gingivae associated with the mandibular, second bicuspids was examined by light microscopy and was classified as to degree of inflammatory involvement. In a comparison of germ-free and conventional animals, the distribution of the degree of inflammation proved to be random. Correlation between mast cell densities and the degree of inflammatory infiltration was not statistically significant. However, mast cells tended to decrease as the inflammation became more severe. Electron microscopic examination of mast cells in the buccal mucosa revealed no difference in morphology of cells from germ-free or conventional animals. Cytoplasmic granules were of two basic types, one exhibited an amorphous matrix of uniform density and the other consisted of laminated coils of various sizes and densities.


The direct functional chew-in technique in the construction of bite guards.

Bite guards are useful in the treatment of a number of occlusal and temporomandibular joint problems. These include clenching, bruxism, temporary stabilization of loose teeth and temporomandibular joint dysfunctions. A method has been presented for the construction of hard acrylic bite guards using a direct functional chew-in technique. This method produces bite guards which require little or no adjustment in just three short office visits.


Probing of pockets related to the attachment level.

Twenty immediate denture patients with periodontitis participated in a controlled study to determine the relationship between clinical probing of pocket depth and the connective tissue attachment. Maxillary and mandibular anterior teeth were probed clinically by one investigator to determine attachment levels. The mesial and distal facial line angles were probed from the cementoenamel junction and from a coronal bur groove, to the clinically determined attachment level. One hundred and sixteen teeth were measured. The teeth were extracted, rinsed, and stained with 4% methylene blue in 50% alcohol to demonstrate the remaining connective tissue attachment. A second investigator using the same probe as the first measured the distance from the coronal bur groove and cementoenamel junction to the most coronal extension of the connective tissue attachment. These measurements were repeated by the second investigator using a dividing caliper and a millimeter scale with a Vernier. The data were analyzed by an analysis of variance for grouped teeth, pairwise t statistic for all teeth, and an analysis of variance for all teeth. The results showed: the influence of the interaction between the patients and technique of measurement, bench and clinical, was negligible for the grouped teeth and for all teeth. The difference between the clinical and bench measurements was not significant for all the teeth as well. The null hypothesis that the difference between the clinical measurement and bench measurement is zero was satisified.


Hereditary hemorrhagic telangiectasia with gingival lesion. Review and case reports.

A case of hereditary, hemorrhagic telangiectasia is described which has been under observation for more than 8 years. The clinical findings are discussed; light microscopic and electron microscopic findings as well as current research for a causative mechanism and recommended therapy are reviewed. The patient exhibited gingival telangiectatic participation. Another, even more severe case of this disease showed repeated, severe hemorrhage from mucosal lesions in the region of the incisive papilla, severe internal bleeding from the nasal mucosa and the gut and several punctate gingival telangiectases. The occurance of gingival lesions may not be as rare as thought. Such lesions may simply be rather inconspicuous.


Clinical results of the measurement of occlusal wear of complete dentures.

This study supports the clinical impression that acrylic resin teeth wear down faster than porcelain teeth but does not support Myerson's view that the total wear of acrylic resin opposing porcelain teeth is less than that of acrylic resin opposing acrylic resin teeth. There was a wide range of rate of wear in acrylic resin teeth opposing acrylic resin teeth. Dentures of the four subjects in the porcelain-only group showed considerably less wear. The dentures with acrylic resin teeth opposing porcelain teeth showed the same general trend, i.e., a high rate of wear for the acrylic resin teeth with very little for the porcelain teeth. Conclusive proof is given for the differing wear rates of acrylic resin and porcelain teeth when opposing like materials.


In vivo evaluation of marginal leakage of four inlay cements.

Marginal leakage was demonstrated in all the inlays at all time intervals with all cements by the use of the isotope Ca45. Gross marginal leakage was observed in all inlays luted with the cyanoacrylate cement at all time intervals. The setting time of this cement is very short, making it difficult to completely seat the inlay before the cement sets. The results of this study indicate that the cyanoacrylate cement is not a satisfactory luting medium for Class V inlays. Inlays cemented with EBA demonstrated leakage patterns similar to those of inlays seated with polycarboxylate and zinc phosphate cements in the specimens taken at 72 hours. In the 3 month and 6 month specimens, greater marginal leakage was seen with EBA cement than with polycarboxylate and zinc phosphate cements. Leakage patterns associated with polycarboxylate and zinc phosphate cements were very similar at all time intervals. The polycarboxylate and zinc phosphate cements showed less marginal leakage than the other two cements at 3 months and 6 months. The results of this study indicate that inlays cemented with polycarboxylate cement and zinc phosphate cement exhibit significantly less marginal leakage than the cyanoacrylate cement and EBA cement over a 6 month period of time.


The relationship of bevels to the adaptation of intracoronal inlays.

The elongation of Types II and III gold alloys ranges from 20 to 35 per cent. It has therefore been proposed that a nonbeveled margin could be "pulled" (elongation) to close the margin. However, in clinical practice, it is difficult to pull gold over an unsupported space to close the margin. Furthermore, the thin area of gold that would be pulled toward the margin could easily be sheared or abraded during finishing. Malleting or swaging a beveled margin is a more sucessful technique of adapting cast gold to the cavosurface angles.


Adhesion of polycarboxylate cements to dental casting alloys.

The adhesive strengths of four commercial polycarboxylate cements to five dental casting alloys were compared with the strength of a conventional zinc phosphate cement. The following results were obtained. (1) The polycarboxylate cements showed adhesion that was four to 12 times greater than that of the zinc phosphate cement to all alloys tested. (2) The adhesive strength of the polycarboxylate cements was greater to the chemically active substitute alloys, such as the copper, nickel-chromium, and silver-tin-zinc alloys. The adhesion of the polycarboxylate cements to the chemically stable gold and silver-palladium alloys was not as great, but was four to six times that of the zinc phosphate cement. (3) The difference in adhesive strength between the brands of polycarboxylate cement was generally slight or statistically insignificant.


Temporomandibular joint function and its effect on concepts of occlusion.

Many of the premises of dentistry that have evolved empirically have been re-evaluated in the light of newly-developed concepts of TMJ function. Centric relation, although duplicable, may not necessarily be correct. A "functional" centric relation exists when the TMJ radiographs can be correlated with the occlusal findings, in which case, the retruded classical centric relation should be used. When a "dysfunctional" centric relation is present (no correlation between the TMJ radiographs and occlusal findings), the most retruded position should not be used and a therapeutic centric occlusion should be created by the dentist. Subclinical TMJ dysfunction occurs more frequently than commonly thought, because TMJ radiographs are not routinely used. Retruded condylar displacements can be easily overlooked, because the lateral pterygoid muscle has relatively few stretch receptors compared to the elevator muscles of the mandible. Condylar retrusion, therefore, would not necessarily cause lateral pterygoid spasm as might be expected. The exact mechanism of the TMJ suspension system is unknown, although experimental evidence has shown that the condyle can be displaced superiorly with posterior unsupported muscle force. This indicates that the immutability of the condylar path under varying clinical conditions is questionable. Due to the superior displacement characteristics of the TMJ, the condyle does not act as the fulcrum in mandibular kinetics. The fulcrum, therefore, shifts to the teeth and/or bolus, depending on the specific situation. In either instance, whether considering bruxism or mastication, for most patients, an occlusion based on group function is preferable to a canine-protected occlusion to insure TMJ health. Scientifically, no one scheme of occlusion or articulation has been proven to be superior to any other scheme; therefore, the choice is a matter of the personal preference of the dentist.


A histologic comparison of effects of electrosurgical resection using different electrodes.

Electrosurgery is a helpful adjunct to restorative dentistry, yet there often is damage to underlying connective tissue. In this study, small loop electrodes demonstrated a wider area of coagulation necrosis than was found with needle electrodes. In all instances, coagulation necrosis as a result of heat was noted. To help minimize tissue damage, very fine wire electrodes should be used, and entry into deep tissue layers should be avoided.


Ultrastructure of platelet aggregation in refractory anemia and myelomonocytic leukemia. I. Ultrastructure of aggregation in normal controls and general defects in refractory anemia and myelomonocytic leukemia.

In vitro aggregation of the platelets from four patients with refractory anemia and two patients with acute myelomonocyctic leukemia revealed distinctive abnormalities. In five patients, there was deficient or minimal aggregation with adenosine diphosphate (ADP), epinephrine, or collagen and only one wave of aggregation could be elicited with ADP at any concentration. Ultrastructural studies revealed numerous isolated platelets, small aggregates with few platelet pseudopods, and the presence of a characteristic type of aggregate with heterogeneous platelet composition combining features of both the primary and the secondary waves of aggregation. These "mixed aggregates" were particularly abundant in the four patients who had refractory anemia and may constitute the structural basis of the single wave of aggregation observed.


Causes of death in adults with acute leukemia.

The causes of death were investigated in 315 adults with acute leukemia during a 7-year period (1966-1972). Infection alone or in combination was the most common cause (75%), followed by hemorrhage (24%) and organ failure (9%). Most of the infections were either systemic or pulmonary. Seventy-five percent of the systemic infections and 72% of the pneumonias were caused by bacteria. Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa were the most frequent organisms isolated. After 1968, there was a sharp decrease in the number of fatal infections caused by Pseudomonas aeruginosa and a marked increase in the incidence of fatal infections caused by Klebsiella spp. and E. coli. Infections caused by Gram-positive cocci occurred in only 3% of the cases. The incidence of systemic fungal infections was 13%; most common fungi causing infection were Candida spp. and Aspergillus spp. Eighty-five percent of 159 patients with a terminal neutrophil count of less than 100/mm3 died of infection, compared to 48% of 62 patients with a terminal neutrophil count of greater than 1000/mm3. Hemorrhage was mostly due to thrombocytopenia (61%) and disseminated intravascular coagulation (12%). This study indicates that infection continues to be the most common cause of death in patients with acute leukemia. Although advances in antibiotic therapy have changed the distribution of causative organisms, ultimate control of infection requires further improvements in supportive care measures which rectify impairments in the patients' host defense mechanisms.


Risk factors of sports injuries in winter.

During the winter season (1 April-31 August) of 1972, 2529 sporting injuries were treated in Wellington and Hutt Accident and Emergency Departments. A computerised analysis was made of the answers to a questionnaire filled out by each patient. Over 90 percent occurred playing major team sports, the majority while playing rugby (57 percent). The rate of injuries was found to be independent of the week of the season, socioeconomic status, race or position played, but was related to age, team sport, and grade played. The majority occurred during games in the weekend. Boys under 13 years of age are rarely injured whereas senior and older players are more frequently injured, especially in the second half of play. It is proposed that competition and the velocity of impact are important contributing factors in major sporting injuries.


Neonatal at risk factors, visual defects and the preschool child: A report from the Queen Mary Hospital multidisciplinary child development study.

An experimental group of 142 children aged four years who had experienced neonatal at risk factors and a control group of 112 children whose perinatal histories were optimal had vision screening tests to detect defective vision or strabismus. Five (3.5 percent) in the at risk group and 10 (8.9 percent) in the control group (total 15, 5.9 percent) were found to have a visual defect. Of those, six had already been identified because of a manifest squint. Nine children with defective vision were first identified through the study. The importance of the early identification and treatment of visual disorders, particularly amblyopia, is emphasised, and recommendations are made for more widespread vision screening of preschool children.


Malakoplakia of the testis.

Two cases of malakoplakia of the testis are presented. Malakoplakia (soft plaque) is an uncommon chronic inflammatory condition of granulomatous type, the common denominator of which would appear to be an altered reactivity of macrophages. Its hallmark is the presence of Michaelis-Guttman bodies. Until the late 1950s, when a case involving the testis was described, the condition was thought to involve only the mucosae of the bladder, ureters, and renal pelvis. The most recent review of malakoplakia of the testis included only 10 known cases.


Ventilatory abnormalities in hospital admissions.

The incidence of unrecognised ventilatory impairment was investigated in a group of 531 routine hospital admissions who had been considered to be free of significant respiratory disease. Using spirometric tests of FEV 1, FVC and FEV 1/FVC percent before and after sympathomimetic bronchodilator, it was found that 42 percent of these patients had abnormal ventilatory tests, and 47 percent were considered to have obstructive lung disease. Routine use of screening respiratory function tests would be useful in the assessment and management of general medical and surgical hospital admissions.


Antibiotic resistance of shigellas in New Zealand.

A WHO assisted survey of antibiotic resistance of Shigella sp from various countries in the Western Pacific Region was carried out by the National Institute of Health, Tokyo, Japan. Of 282 unselected isolates from throughout New Zealand, 221 (78 percent) exhibited resistance to one or more antibiotics. The implications of these results in relation to treatment are briefly discussed.


Chlamydial ophthalmia neonatorum.

A case of chlamydial ophthalmia neonatorum is presented. The importance of early diagnosis and treatment is discussed.


The second oncogenic step.

Three theories of the development of a malignant change which each involve two successive steps are described. Armitage, Doll (1957) proposed that two homologous chromosomes each contained a region which was critical in the control of cell division. The two steps were mutations in these regions brought about by random exposure to carcinogenic agents. Comings (1973) proposed a similar theory but the two steps were considered to be spontaneous mutatons. This paper points out that if one mutation has occurred this can become dominant in at least six ways which mostly involve chromosome translocations. The synergism between oncogenic agents and ionizing radiation and the ability to breed out high and low cancer incidence stocks of animals from a common stock can be explained on the same lines.


Out of hours calls.

Approximately 1000 out of hours calls performed by Auckland general practitioners are analysed. These were all general practitioners who personally or by the use of rosters care for their own patients. In a subsequent study it is intended to compare the out of hours work done by a deputising service.


A new tetracycline minocycline compared with ampicillin in general practice.

A new tetracycline (minocycline) and ampicillin were compared in the treatment of 217 adults with common infections seen in general practice. Minocycline had an overall clinical effectiveness comparable with ampicillin, though minocycline was more frequently prescribed for suspected staphylococcal infections with satisfactory results in 25 (26). Minocycline was significantly more effective in vitro against common pathogenic organisms than ampicillin. All strains of staphyloccocci isolated were sensitive to minocycline while 15 (27) were resistant to ampicillin. Minocycline and ampicillin were no different in the occurrence of mild side effects. Dizziness was troublesome for 23 (127) patients on minocycline and resulted in four patients discontinuing treatment.


Familial reactive arthritis of Reiter's and ankylosing spondylitis types in the HLA-27 genotype.

The close relationship between Reiter's disease and ankylosing spondylitis, which had previously been suspected on the grounds of family and population studies, has been re-emphasised following the recent demonstration of their common close association with the HLA-27 genotype. Nevertheless there are few case reports of both conditions occurring simultaneously in first degree relatives; and documentation of HLA genotype in such families was not generally considered before 1973. Both varieties of reactive arthritis are reported here as occurring in first degree relatives sharing HLA-27 genotype.


Dysphagia: caveat oesophagum.

The seriousness of dysphagia as a symptom is emphasised. Two illustrative cases are described in which carcinoma of the oesophagus causing dysphagia was diagnosed late. The importance of early barium studies and early oesophagoscopy is stressed. The poor results of management of carcinoma of the oesophagus associated with late diagnosis are illustrated in the patient data presented.


Cast brace application and early ambulation as a treatment of femoral shaft fractures.

A report on experience with early cast brace application and ambulation as a treatment for fractures of the femoral shaft is presented. A case for continuing this type of treatment is made.


Chronic chest wall sinus: an unusual presentation of typhoid.

A chronic discharging sinus of the chest wall is described in a 59-year-old Maori woman investigated as a typhoid contact. A heavy growth of Salmonella typhi organisms was cultured from the sinus, which had first appeared 13 years previously.


Alcaligenes faecalis septicaemia.

A case of Alcaligenes faecalis septicaemia occurring after appendicectomy is described, and previous reports of this condition are briefly reviewed. Alcaligenes is frequently found in the faeces of healthy people and systemic infections appear to be very uncommon. Nevertheless, if the organism is cultured from the blood it should not be dismissed as a contaminant without careful investigation.


Macrogenia: a study of treatment results, with surgical recommendations.

1. A retrospective cephalometric study of patients who underwent reduction genioplasties showed large variations in soft-tissue response to osseous reduction. 2. The vertical and horizontal soft-tissue changes coincident to osseous reduction were less than expected. The maximum soft-tissue change observed was approximately 50 per cent that of the hard tissue removed. On the average, the vertical soft-tissue change was about 30 per cent and the horizontal was 25 per cent, when degloving procedures were combined with some form of ostectomy. 3. A considerable length of time is necessary before the soft-tissue changes are stable after reduction genioplasty. In some cases, significant changes occurred up to 8 to 10 months postoperatively. 4. A classification of macrogenia is proposed, based upon a more exact anatomic description of the deformity. 5. On the basis of this classification, the results of the present study, and more recent clinical results, recommendations for the surgical treatment of macrogenia are made.


Inverted L-shaped ramus osteotomy for prolonged bilateral dislocation of the temporomandibular joint.

The various methods of management of prolonged bilateral anterior dislocation of the temporomandibular joints are discussed and the literature is reviewed. Reported is a case in which a bilateral inverted L-shaped ramus osteotomy was performed in order to reposition the mandible and establish normal occlusion; the results were satisfactorily maintained one year postoperatively.


The use of methylmethacrylate in the fixation of mandibular fractures in dogs. Experimental results.

The efficacy of self-curing acrylic resin in the fixation of fractured mandibles was studied in eight adult mongrel dogs. Three dogs were killed at 1 month, two at 3 months, and three at 6 months after insertion of the resin. Roentgenograms taken after operation and after the dogs had been put to death demonstrated satisfactory fracture reduction and bony healing. The retentive grooves appeared larger on the postmortem roentgenograms, apparently from fibrous tissue that formed between the acrylic resin and the bone. Sections through the groove and fracture site did not show any fibrocartilage formation between the bone and the resin. Active osteoblastic activity was present at the fibrous capsule-bone interface as well as in the fracture calluses. Most sections showed acute inflammation, with a few giant cells. Whether the inflammatory component resulted from tissue breakdown over the acrylic resin or from the polymethylmethacrylate itself was not determined. There was no evidence of abnormal healing or nonunion along the fracture line and no evidence of necrotic bone. The undecalcified tetracycline-labeled sections confirmed active bone formation at the fibrous capsule-bone interface and in the fracture calluses at 1, 3, and 6 months. No mobility could be detected across the fracture site at any time after the insertion of the acrylic resin. Two of the three dogs that were killed at 1 month had incomplete bony union, as demonstrated by mobility along the fracture line seen in the resected specimens. Mucosal dehiscence over the superior acrylic fixation bar was a consistent finding. Once the resin had been either exfoliated or removed, the mucosa healed uneventfully. The insertion of methylmethacrylate did not result in blood pressure change in the dogs. The dogs maintained their preoperative weight, appetite, and jaw mobility. Although satisfactory bony healing resulted from the intraoral open reduction and fixation with self-curing acrylic resin in dogs, several factors need additional investigation before this technique can be considered for use in human subjects. The following findings in this study may contribute to healing complications in man: (1) loosening of the acrylic resin due to fibrous tissue formation between it and the bone, (2) mucosal dehiscence, (3) inflammation in and around the fibrous tissue adjacent to the acrylic resin, and (4) the necessity of bone removal to facilitate the insertion of the resin.


Erythema multiforme. Review of twenty-six cases.

A survey of twenty-six cases of erythema multiforme was undertaken. All patients had oral lesions and seventeen had skin involvement, mainly on the hands. The average age was 32 years, and female patients predominated in the group. Nearly one third gave a history of a severe emotional disturbance prior to the attack, four patients developed lesions after penicillin therapy, and two presented initially with acute primary herpes simples stomatitis. Skin and mucosal biopsies were undertaken in some patients, and it was concluded that no pathognomonic features were identifiable; a subepithelial bulla, however, could occasionally help in the differential diagnosis. Other laboratory investigations, including a complete blood count, determination of herpesimplex titer, and urinalysis, were not helpful, except that the erythrocyte sedimentation rate was raised in sever cases. Possible etiologic factors were discussed in relation to the survey. It was thought that the cause is still obescure except in drug-induced cases and that the diagnosis is essentially a clinical one, since various laboratory investigations cannot be shown to produce consistent pathognomonic findings.


Allergic stomatitis caused by self-polymerizing resin.

This is a fully documented case, including biopsy and patch testing, of a patient who was hypersensitive to self-polymerizing polymethyl methacrylate. On two occasions, a 24-year-old woman with a history of multiple allergies developed allergic reactions to temporary acrylic dental restorations. The lesions disappeared upon removal of the restorations. Microscopic findings were consistent with an allergic reaction. Patch testing confirmed that the allergen was the monomer and indicated methods of processing the self-polymerizing resin to allow it to become essentially nonreactive in a sensitized patient.


Intraosseous angiolipoma of the mandible.

A case of intraosseous angiolipoma, one of the rarest benign tumors of bone, is reported. This tumor represents an example of an intraosseous neoplasm consisting of both blood vessels and fat. To our knowledge, such a tumor of the mandible has not been reported previously.


Sweat gland carcinoma of the lips.

Sweat gland carcinomas are extremely rare tumors with a fully malignant potential. Two cases of primary sweat gland carcinoma of the lips are presented. Because of the unique nature of this lesion, the histopathology and biologic behavior are discussed, and the pertinent literature is reviewed.


Carcinoma arising in the area of median rhomboid glossitis.

Routine soft-tissue examination of a 44-year-old Negro woman who consulted her dentist for a new maxillary partial denture revealed a depressed white lesion in the area of median rhomboid glossitis. Biopsy diagnosis of the area was well-differentiated squamous-cell carcinoma. The relation of this lesion to median rhomboid glossitis is questioned in view of previous reports.


The predentin index.

This is the initial report of a new, objective means of determining early pulpal reaction to an insult. The method consists of (1) direct measurement of the thickness of the predentin in the crown and cervical portions of each tooth, (2) determination of the Predentin Index, and (3) subsequent comparison of the PI's of control versus experimental teeth. If the Predentin Index of the experimental is lower than that of the control, a pulpal injury has occurred. Reliance on the subjective, interpretive ability of the observer is effectively eliminated.


Misdiagnosis of an impacted supernumerary tooth from a panographic radiograph.

A panographic radiograph of a 31-year-old man revealed the presence of an impacted supernumerary paramolar. Periapical radiographs of the same area failed to confirm the existence of this supernumerary tooth. A review of the inherent distortion factors present in panographic radiography leading to the misdiagnosis is discussed.


Roentgenologic study of the mental foramen.

Locating the mental foramen in periapical radiographs is of great clinical importance. One thousand full-mouth intraoral radiographs were examined, and the location of the mental foramen in both the horizontal and the vertical planes was registered. In the horizontal plane 70 per cent of the mental foramina were found to be located between the two premolars, and 22 per cent were in the apical area of the premolars. In the vertical plane the highest percentage of mental foramina was found to be located superior to the level of the apices of the premolars.


The cracked-tooth syndrome and fractured posterior cusp.

1. Even from such a small sample as that reported in this study, it is evident that the fractured cusp and cracked-tooth syndrome are common problems. The large number of fractured cusps compared to the cracked-tooth syndrome suggests that some of the cases of fractured cusp could have been diagnosed earlier. 2. It is most important that dentists be aware of the cracked-tooth syndrome in order to relieve the patient's discomfort, prevent the possible eventual loss of the pulp or tooth, and avoid unnecessary and possibly damaging treatment for misdiagnosed facial pain. 3. Conservation of tooth structure in restorative procedures is most necessary in order to prevent the cracked-tooth syndrome or fractured posterior cusp.


The antilingula as an anatomic landmark in oral surgery.

The antilingula is a highly variable anatomic landmark and in most instances is situated considerably anteriorly and superiorly to the inferior dental foramen. However, a cut made between 5 and 10 mm. distal to the antilingula is within a statistically safe area, in over 72 per cent of cases, to avoid encroaching upon the inferior alveolar foramen.


Soft-palate pigmentation in lung disease, including cancer.

A study of patients in whom soft-palate pigmentation appeared to be associated with pulmonary disease has been reported. A significant number of these patients had diagnosed or suspected bronchogenic carcinoma. The possibility that this oral finding may be predictive of the presence of lung cancer, or of a high degree of probability of future development of lung cancer, indicates a need for additional investigation. At this point the evidence strongly suggests that when soft-palate pigmentation is seen in a patient with lung disease, cancer should be suspected until it is definitely ruled out. The paucity of patients in whom this sign is seen suggests the need for study by other investigators. ACTH levels should be evaluated, as should plasma zinc values, which have been demonstrated to decrease in lung cancer as well as other diseases. Following the patients prospectively certainly is indicated. In conjunction with the Department of Laboratory Medicine, limited initial additional investigations have been made of the carcinoembryonic antigen (CEA) levels on three of the outpatients reported. These assays used the hemagglutination-inhibition technique and are limited to investigational use by the Food and Drug Administration. In this laboratory the normal CEA level is 5.2 +/- 1.6 ng./ml. Results in two patients with known chronic obstructive pulmonary disease were 5.5 and 5.6 ng./ml. The third patient with soft-palate pigmentation and an undiagnosed pulmonary problem had a CEA level of 10.2 ng./ml. She also had clubbing of the fingers. The senior author would be particularly interested in establishing a registry of similar cases observed by others.


Acute angioneurotic edema of the lips and tongue due to emotional stress.

Angioneurotic edema, though a fairly common medical condition, is rarely seen in dental practice. As laryngeal involvement can occur spontaneously and suddenly in the dental office or a similar complication can develop abruptly after administration of certain drugs used in dentistry, an understanding of this condition is definitely indicated. Moreover, as the hereditary form of this clinical entity can be precipitated by trauma, such as various dental and oral surgical procedures with a high incidence of laryngeal edema, an awareness of this phenomenon is an absolute necessity for sound medical and dental practice.


Mucosal ganglioneuromatosis, medullary thyroid carcinoma, and pheochromocytoma: multiple endocrine neoplasia, type 2b.

Multiple endocrine neoplasia, type 2b, is a designation that has been proposed for the combination of medullary thyroid carcinoma, pheochromocytoma, mucosal neuromas, and somatic abnormalities. The neural lesions produce a characteristic diffuse or nodular enlargement of lips, tongue, and buccal mucosa. Microscopically, the lesions are composed of unencapsulated masses of hypertrophied and elongated nerves in which are found rare ganglion cells. The histologic similarity between the oral mucosal lesions and the alimentary tract ganglioneuromatosis in the syndrome suggests that the term ganglioneuromatosis is the most appropriate designation for the oral lesions. The oral lesions signal high risk for two potentially lethal neoplasms--medullary thyroid carcinoma and pheochromocytoma. Thus, patients having the characteristic findings are in urgent need of repeated evaluation of thyroidal C-cell and adrenal medullary function.


Calcifying odontogenic cysts with intracellular amyloid-like material.

Intracellular deposits of amyloid as defined by positive Congo red staining with green polarization birefringence and standardized toluidine blue staining with pink-red polarization birefringence were observed in the epithelial lining of three cases of calcifying odontogenic cysts. It is suggested that this material is not true amyloid but, rather, a dengenerative product of the epithelial cells as has been described in calcifying epithelial odontogenic tumor (Pindborg tumor).


Meningioma presenting as an intraoral mass.

The following case report illustrates a rather rare oral lesion, an extracranial meningioma. In the dental office the lesion was seen on a periapical x-ray film as a multilocular radiolucency. The patient, however, could not be convinced of the necessity of biopsy until several years later when clinical expansion of the maxillary buccal plate was noted. Thereafter, clinical, radiographic, and histopathologic examination revealed a diffuse meningioma involving the maxillary sinus, the floor of the nose, and the maxillary gingiva. The patient has since refused complete surgical removal but remains alive and well 8 years after the lesion was first noted.


Leakage of different root canal sealants.

One hundred five single-rooted teeth were prepared and filled with ten commercially available root canal paste sealers. Five teeth were filled with only gutta-percha points, fifty teeth were filled with a particular cement alone, and the rest of the teeth were filled with a particular cement in conjunction with gutta-percha points. It was found that the gutta-percha point alone is not sufficient for sealing the periapical foramen; nor are N2 (Sargenti), Riebler's paste, and the iodoform paste. In general, it was found that the combination of gutta-percha and cement is more effective in sealing the periapical foramen. Polycarboxylate cement used in this investigation, although it does not meet all the requirements of a good root canal sealant, was found to yield promising results.


The use of iodine as a contrast medium in endodontic therapy.

The present study describes the use of 10 per cent iodine in potassium iodide as an intradental x-ray contrast medium in the search for root canals or parts of root canals which were not detected in radiographs or by instrumentation. In most teeth with periapical radiolocencies a passage through the entire root was found by means of the contrast medium, but in the teeth without periapical involvement usually no communication was detected. According to the results of the present study, an intradental contrast medium may be useful in the search for apparently obliterated root canals.


Television radiographic evaluation of periapical osseous radiolucencies.

Periapical lesions were experimentally induced in forty-five teeth of seven beagle dogs by both septic and aseptic techniques. Preoperative and postoperative serial radiographs were produced with a specifically designed animal head x-ray device, at 30-, 60-, and 90-day periods. Four anatomic study areas, which consisted of the cervical, interradicular, proximal root, and periapical areas of each tooth, were evaluated by viewbox observation of radiographs, television subtraction radiographic imagery, and histologic examination. The findings obtained with the subtracted image and histologic examinations were correlated with viewbox observations. Diagnostic evidence of periapical pathosis was identified in the subtracted image 7 to 42 days before this same evidence was noted on the viewbox radiograph. The periodontal membrane space, lamina dura, bone trabeculae, and medullary spaces were markedly enhanced, with defined outlines of the periapical lesions noted in the subtracted image.


Japanese tooth positions and their relation to panoramic radiography.

1. Tooth positions did not vary between ages and sexes in Japanese. 2. As the arches lengthened posteriorly, anterior tooth positions showed little variation. 3. Japanese tooth positions lie within the range shown for Caucasoid and Negroid persons. 4. Japanese tooth positions have a shorter anteroposterior dimension than their Caucasoid and Negroid counterparts. 5. The relationships of Japanese positions to the Panorex, Panelipse, and Orthopantomograph are similar to those found for Negroid and Caucasoid persons.


A quantitative comparison of paralleling long-cone and bisection-of-angle periapical radiography.

Quantitative data permit the variability comparison of crown-root ratios computed from periapical films of a single central incisor taken by five technicians using the bisection-of-angle and the paralleling long-cone techniques. The paralleling long-cone technique produces significantly less distortion and is less variable. It is the method of choice for assessing natural root resorption and resorption due to orthodontic therapy.


Fowl plague virus adapted to human leukemia cells: interaction with normal human leukocytes and plastic surfaces.

An avian influenza A virus which grows well in human leukemic myeloblasts was unable to replicate in normal human leukocytes. The virus adhered during the first hours of incubation to plastic surfaces and to leukocytes and was then released into the supernatant; care should be taken not to confuse this with viral growth.


[Focal epithelial hyperplasia].

A case of focal epithelial hyperplasia in a 36-year old norwegian caucasian women is described. The patient presented 5 papules, 2-7 mm in diameter. The papules were found on the mucosa of the lower lip and left cheek (Fig. 1). Another elevation was situated on the buccal gingiva in the lower left canine/first premolar region. Histologic examination of the lesion shown in Fig. 1 revealed epithelial hyperplasis with acanthosis (Fig. 2). Cells with swelling of the nucleus and cells with mitosoid nuclear degeneration were seen in the upper stratum spinosum (Fig. 3). A mild degree of lymphocytic infiltration of the connective tissue was present. The histologic appearance is similar to that reported by Clausen (1969).


Uncoupling of local field spectra in nuclear magnetic resonance: determination of atomic positions in solids.

Solid state nuclear magnetic resonance as a method of determining crystal structure has had limited success. Three distinct reasons for this failure can be identified when the resonance spectrum is of a dilute spin species in the presence of another abundant species. Two of these difficulties, and in part the third, can be mitigated by a family of coherent averaging techniques in double resonance, with considerably improved prospects for locating the rare spins with respect to their nearby neighbors. A particularly advantageous procedure is described and possible applications are discussed.


2-diazo-3,3,3-trifluoropropionyl chloride: reagent for photoaffinity labeling.

2-Diazo-3,3,3-trifluoropropionyl chloride has been synthesized from trifluorodiazoethane and phosgene. Its derivatives are acid stable, can be used to label enzymes, and undergo photolysis with substantially less rearrangement than do derivatives of other known diazoacyl reagents designed for photoaffinity labeling. In particular, the diazotrifluoropropionyl thioester of methyl N-acetylcysteine undergoes photolysis in methanol with about 40% insertion into the - OH bond of the solvent; by contrast, photolysis of other diazoacyl thioesters gives substantially quantitative Wolff rearrangement. The trifluoro compounds hold promise for the photoaffinity labeling of thiols.


Comparative study of alkaline phosphatase activity in lymphocytes, mitogen-induced blasts, lymphoblastoid cell lines, acute myeloid leukemia, and chronic lymphatic leukemia cells.

Alkaline phosphatase [orthophosphoricmonoester phosphohydrolase (alkaline pH optimum), EC 3.1.3.1] purified from a Burkitt lymphoma cell line (Daudi) and Moloney-virus-induced murine leukemia (YAC) showed unique catalytic properties in substrate specificity and inhibition by cysteamine-S-phosphate. It migrated on polyacrylamide gel electrophoresis in a single activity band. Alkaline phosphatase with similar properties was found in several human lymphoblastoid cell lines, in chronic lymphatic leukemic cells, in organs of leukemic mice, and in sera of patients with certain lymphoproliferative disorders.


Elucidation of hydrocarbon structure in an enzyme-catalyzed benzo[a]pyrene-poly (G) covalent complex.

The carcinogen, benzo[a]pyrene, was covalently attached to poly (G) by liver microsomes from rats pretreated with 3-methylcholanthrene. The complex was hydrolyzed with enzymes or base and products were isolated by Sephadex chromatography. Absorbance and fluorescence spectra of the products fit that of red-shifted pyrene aromatic system and suggest that metabolism has occurred at the 7-, 8-, 9-, and 10-positions of the hydrocarbon. Benzanthracene or chrysene fluorescence were not observed in these preparations. Benzo[a]pyrene derivatives were synthesized and purified by high-pressure liquid chromatography. Dehydration of 7,8-dihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene resulted in the formation of small amounts of 7-oxo-7,8,9,10-tetrahydrobenzoa[a]pyrene. A 7-keto species was also observed after similar treatment of the hydrocarbon-poly(G) hydrolysis products. Evidence of dehydration at the 9,10-positions was not observed. The hydrocarbon covalently bound to poly(G) is, therefore, a derivative of 7,8-dihydroxy-7,8,9,10-tetrahydrobenzol[a]pyrene with nucleic acid substitution at C-10 or 9.


Induction of vitellogenin synthesis by estrogen in avian liver: relationship between level of vitellogenin mRNA and vitellogenin synthesis.

We have investigated the estrogen-mediated induction of vitellogenin synthesis in rooster liver. We compared the concentrations of vitellogenin messenger RNA (mRNA) in the liver with the concentrations of vitellogenin in the sera of roosters that had recieved various treatments with estrogen. We found no vitellogenin mRNA in the livers of the unstimulated roosters. An initial injection of estrogen was attended by de novo synthesis of vitellogenin mRNA in the liver and accumulation of vitellogenin in the serum. When vitellogenin was no longer present in the serum or liver (the "post-estrogen-serum-negative" state), the liver was found to contain appreciable amounts of vitellogenin mRNA. This mRNA was of the same size as that found in the liver of the rooster actively synthesizing vitellogenin in response to estrogen. Whereas vitellogenin mRNA was in large polysomes in the livers of the roosters actively synthesizing vitellogenin, the vitellogenin mRNA in the liver of the post-estrogen-serum-negative rooster was not associated with polysomes. The possible relevance of these findings to the fact that the rooster responds differently to a primary stimulation with estrogen than to subsequent stimulations is discussed.


Characterization of a gamma-carboxyglutamic acid-containing protein from bone.

A gamma-carboxyglutamic acid-containing protein has been purified from the calcified tissues of several vertebrates. The presence of three-gamma-carboxyglutamic acid residues in the bovine protein was established by alkaline hydrolysis and amino acid analysis, a method based upon studies with synthetic gamma-carboxyglutamic acid. The identity of gamma-carboxyglutamic acid in the bovine protein was established by mass spectroscopy on the unknown amino acid isolated from alkaline hydrolysates.


On the obligatory role of the hypophysis in sexual differentiation hepatic metabolism in rats.

The hepatic metabolism of 4-[4-14C]androstene-3,17-dione and 5alpha-[4-14C]androstane-3alpha,17beta-diol was studies in castrated and hypophysectomized male rats with a transplanted pituitary under the kidney capsule. The effects of testosterone propionate and estradiol benzoate on liver metabolism were also studied in these experimental animals. It was found that the autonomous pituitary secreted a "feminizing factor" that transformed the male type of steroid metabolism characteristic of hypophysectomized rats into a female type of metabolism Hypophysectomized rats were unresponsive towards androgen action on the liver and did not respond with feminized hepatic metabolism after treatment with estradiol benzoate. It is concluded that estrogenic action on liver enzymes is mediated via modulation of the secretion of a central (probably hypothalamic) "feminizing factor inhibiting factor" and the sex hormonal effects of hepatic metabolism only occur in the presence of a pituitary in situ.


Synthesis of nuclear proteins during DNA repair synthesis in human diploid fibroblasts damaged with ultraviolet radiation of N-acetoxy-2-acetylaminofluroene.

We have examined the accumulation of newly synthesized nuclear proteins into nuclei during DNA repair synthesis in confluent WI-38 human diploid fibroblasts damaged with ultraviolet radiation or N-acetoxy-2-acetylaminofluroene. In contrast to a marked stimulation of DNA repair synthesis, stimulation of amino acid incorporation into histone polypeptides or into the various molecular weight classes of nonhistone nuclear proteins was not observed. These results suggest that detectable stimulation of newly synthesized nuclear protein incorporation into nuclei does not accompany DNA repair synthesis induced by ultraviolet radiation or a direct acting chemical carcinogen. At least for the special case of repair, DNA synthesis may be uncoupled from histone synthesis.


Biological consequences of incorporation of 5-fluorocytidine in the RNA of 5-fluorouracil-treated eukaryotic cells.

Treatment of HeLa cells with 5-fluoro-[3H]uracil leads to the incorporation into cellular RNA of 5-fluorocytidine to the extent of about 0.2% of the 5-fluorouridine incorporated. In tobacco mosaic virus RNA produced in tobacco leaves this ratio is one order of magnitude lower. Copolymers of cytidylic with 5-fluorocytidylic acids show unchanged template activity with E. coli RNA polymerase, but slightly altered messenger activity in the wheat germ system, compared to poly(C), and it is suggested that some of the biological consequences of 5-fluorouracil treatment of living cells and organisms may be attributed to this mechanism.


Ability of insulin to increase calcium binding by adipocyte plasma membranes.

Calcium specifically binds to adipocyte plasma membranes, demonstrating two classes of binding sites having affinity constants of 4.5 x 10(4) M-1 and 2.0 x 10(3) M-1. Insulin (100 microunits/ml) added directly to the isolated plasma membranes caused no alteration in calcium binding, whereas incubation of the adipocytes with 100 microunits/ml of insulin resulted in a 2.50 +/- 1.6% increase in calcium binding to the subsequently isolated plasma membranes. The increase in calcium binding produced by insulin resulted from an increase in the maximum binding capacities of both classes of binding sites without alteration in their affinity constants. Additionally, a second pool of calcium in adipocyte plasma membranes has been identified by atomic absorption analysis; it was more than two times larger than the maximum binding capacity of the calcium binding system. This pool of calcium was stable, did not participate in the 45Ca2+ exchange, and was unaltered by insulin treatment. A simialr stable pool of magnesium exists in plasma membranes and was also unaffected by insulin treatment. The increased capacity of the isolated plasma membranes to bind calcium after insulin treatment of the cells may represent an important bioregulating mechanism and supports the concept that calcium may play an important role in the effector system for insulin.


A protein binding the methylated 5'-terminal sequence, m7GpppN, of eukaryotic messenger RNA.

Ribosomal salt washes of Artemia salina embryos contain a protein(s) that binds [3H]m7GpppGpC and [3H]m7GpppGmpC, as measured by retention on nitrocellulose membrane filters. These oligonucleotides correspond in structure to the methylated 5'-terminal sequences (caps) present in many eukaryotic mRNAs. The cap binding protein does not bind the unmethylated counterparts of caps, e.g., [32P]GpppGpCp, or a derivative of m7GpppGmpC containing ring-opened m7G. None of the purified initiation factors IF-MP, IF-M2A, IF-M2B, IF-M3, or IF-MI binds the m7G-containing oligonucleotides.


In vitro transcription of chromatin in the presence of a mercurated nucleotide.

Mercurated uridine triphosphate has been used to label transcripts of chicken reticulocyte chromatin made with Escherichia coli RNA polymerase. The mercury-labeled RNA product can be completely separated from endogenous RNA sequences in the chromatin by passage through a sulfhydryl Sepharose column. Globin cDNA hybridization to the transcript shows that only 2.6 x 10-5 of the transcript is globin RNA. In contrast to this result, erythrocte chromatin transcript contains less than one tenth as many globin RNA sequences.


Long-chain neutral glycolipids and gangliosides of murine fibroblast lines and their low- and high-tumourigenic hybrids.

The patterns of long-chain neutral glycolipids and gangliosides of established, L-cell-derived murine fibroblast lines and their low- and high-tumorigenic hybrids were studied.


Presence of messenger specifying sequences in the DNA of chromatin subunits.

Messenger-specifying sequences in subunits of human lymphocyte chromatin were detected by hybridization of DNA complementary to cytoplasmic polyadenylylated RNA with DNA isolated from the subunits. Comparison of the kinetics and extents of hybridization of complementary DNA with chromatin subunit DNA and with nuclear DNA showed that most of the repetitive sequences and single copy sequences in mRNA are present in chromatin subunits. This result indicates that inclusion of a DNA sequence into the subunit does not prevent its transcription in vivo.


Nuclear magnetic resonance study of heme-heme interaction in hemoglobin M Milwaukee: implications concerning the mechanism of cooperative ligand binding in normal hemoglobin.

Hemoglobin M Milwaukee (beta 67E11 val leads to Glu) is a naturally occurring valency hybrid containing two permanently oxidized hemes in the beta-chains. In this mutant, the two abnormal beta-chains cannot combine with oxygen, whereas the two alpha-chains are normal and can combine with oxygen cooperatively with a Hill coefficient of approximately 1.3. High-resolution proton nuclear magnetic resonance spectroscopy at 250 MHz has been used to investigate the hyperfine shifted resonances of the abnormal ferric beta-chains of Hb M Milwaukee over the spectral region from -30 to -60 parts per million from water at pD 7 and 30 degrees.


Hepatic phenylalanine 4-monooxygenase is a phosphoprotein.

Phenylalanine hydroxylase [phenylalanine 4-monooxygenase; EC 1.14.16.1; L-phenylalanine, tetrahydropteridine:oxygen oxidoreductase(4-hydroxylating)] isolated from rat liver is a phosphoprotein containing approximately 0.31 mumol of  protein-bound phosphate per mumol of subunit (50,000 molecular weight). When the enzyme is further phosphorylated in the presence of ATP and a 3'5'-cyclic-AMP-dependent protein kinase (EC 2.7.1.37; ATP:protein phsophotransferase), an additional 0.7 mumol of phosphate per mumol of subunit is introduced, bringing the total phosphate content up to about 1 mumol/mumol of subunit. This phosphorylation of the enzyme in vitro is accompanied by a 2.6-fold increase in hydroxylase activity when the activity is assayed in the presence of tetrahydrobiopterin. Partial proteolytic digestion of phenylalanine hydroxylase, which previously had been shown to activate the enzyme 20- to 50-fold [Fisher, D.B. & Kaufman, S. (1973) J. Biol. Chem. 248, 4345-4353], removes almost all of the phosphate from the enzyme.


An enzyme system for replication of duplex circular DNA: the replicative form of phage phi X174.

Viral single strands (SS) are converted to the duplex from (RF) by a soluble enzyme fraction uninfected Escherichia coli [Schekman et al. (1975) J. Biol. Chem. 250, 5859-5865]. When reactions were supplemented with a soluble enzyme fraction from phi X174-infected cells, replication of phi X174 superhelical RF I DNA was observed. The activity supplied by infected cells was absent in cells treated with chloramphenicol or in cells infected with a phi X174 phage mutant in cistron A (cis A). A host function coded by the rep gene, essential in vivo for RF replication (but not for SS leads to RF), was supplied by enzyme fractions from either infected or uninfected cells. Based on complementation assays, the cisA-dependent and the rep-dependent proteins have each been purified about 1000-fold. The synthetic products of the enzymatic reaction were identified as RF I and RF II in which viral (+) and complementary (-) strands were newly synthesized.


Inelastic electron tunneling spectroscopy of nucleic acid derivatives.

Inelastic electron tunneling spectra of nucleosides and nucleotides are presented which show that detailed information on the vibrational spectra of these molecules can be obtained from a few micrograms of material. A series of studies on adenine derivatives demonstrates that unambiguous identification of a large number of slightly different derivatives can be carried out by means of this technique.


Cell cycle analysis and X-chromosome inactivation in the developing mouse.

The duration of different phases of the cell cycle (G1, S, G2, and M), as well as the exact time of initiation of asynchronous DNA replication pattern in one of the X-chromosomes in the female mouse during the early stages of development, have been investigated. It was found that early developmental stages in the mouse are devoid of G1 period, and from the late blastocyst stage the embryonic cells first acquire all the characteristic stages of the cell cycle (G1, S, G2, and M). Additionally, asynchronous DNA replication pattern in one of the X-chromosomes in the female embryos was found to be initiated with the appearance of the G1 period. I have established a correlation between the onset of the G1 period and the initiation of an asynchronous DNA replication pattern in one of the X-chromosomes of the female mammal during embryogenesis.


Stimulation of prostaglandin E synthesis in cultured human umbilical vein smooth muscle cells.

Cultured human umbilical vein smooth muscle cells secreted 1.26 +/- 0.20 mug of immunoreactive prostaglandin E (iPGE) per mg of cell protein per 24 hr (mean +/- SEM). In indomethacin, an inhibitor of prostaglandin synthesis, abolished greater than 95% of this basal iPGE production (ID50 = 1.8 nM).


An evaluation of messenger RNA competition in the shutoff of human interferon production.

The process that shuts off poly(I)-poly(C)-induced interferon production in a strain of diploid human fibroblasts (FS-4)-involves the synthesis of new RNA, presumably nuclear heterogeneous RNA. When cultures in the shutoff phase of interferon production are treated with actinomycin D (5 mug/ml) or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB 40 muM), the rate of interferon production continues to decline for a further 3-4 hr, but then tends to level off. The treated cultures maintain interferon production at a reduced level for at least 10 hr. The residual rate of interferon production is higher in cultures which received actinomycin D or DRB early in the shutoff phase as compared to the rate in cultures treated late.


Alpha-methyl ornithine, a potent competitive inhibitor of ornithine decarboxylase, blocks proliferation of rat hepatoma cells in culture.

A biphasic increase of putrescine concentration occurs in rat hepatoma tissue culture cells induced to proliferate. DL-alpha-Methyl ornithine, a competitive inhibitor of ornithine decarboxylase ( L-ornithine carboxylyase, EC 4.1.1.7) of hepatoma tissue culture cells, blocks the usual increases of putrescine and spermidine concentrations in these cells, and causes a rapid fall in the levels of putrescine which is followed by a striking decrease of spermidine. In parallel with the depletion of these amines, incorporation of [3H]thymidine into DNA and cell proliferation are inhibited. Addition of putrescine, spermidine, or spermine results in an immediate resumption of cell proliferation. Cell proliferation is also restored by L-ornithine presumably due to in situ competitive inhibition of ornithine decarboxylase. These findings of hepatoma tissue culture cells support the concept that polyamines play an essential function in the cell division processes.


Fluidity in mitochondrial membranes: thermotropic lateral translational motion of intramembrane particles.

The fracture faces of frozen rat liver mitochondria reveal that intramembrane particles can be induced to under go long-range lateral translational motion and aggregation, which parallel the appearance of large, particle-free smooth patches in the hydrophobic interior of the two mitochondrial membranes. These lateral separations were observed under conditions that induce thermotropic lipid-lipid phase separations. Low temperature-induced lateral separation occurred between the intramembrane particles (integral proteins) and smooth patches (bilayer lipid) at temperatures between about 10 and -12 degrees in the outer membrane and between about -4 and -12 degrees in the inner, energy transducing membrane.


The development of the action potential mechanism of amphibian neurons isolated in culture.

Nerve and muscle cells differentiated morphologically, in cultures of dissociated cells prepared from amphibian neural plate and underlying mesoderm (Xenopus laevis, Nieuwkoop and Faber stage 15). Cultures were grown in a defined medium containing sterile Steinberg's salt solution and 0.1% bovine serum albumin, and maintained for periods up to 5 days.


Distribution of annionic sites in glomerular basement membranes: their possible role in filtration and attachment.

Lysozyme (pI = II) has been used to identify anionic sites in the glomerular capillary wall. A solution of 1-3% lysozyme was perfused into the left kidney at varying rates. After perfusion, the kidney was fixed in situ and processed for electron microscopy. Lysozyme was seen as an electron-dense deposit which was not present when succinylated lysozyme (pI = 4.5) or myoglobin (pI = 6.9) was perfused instead of native lysozyme. First, the epithelial cell plasma membrane was outlined by a 300-400 A electron-dense layer. Second, there were discrete dense deposits in the subepithelial portions (lamina rara externa) of the basement membrane which, in normal sections, extended from the epithelial cell membrane to the lamina densa and, in grazing section, formed a continuous reticular pattern.


Different calcium requirements for proliferation of conditionally and unconditionally tumorigenic mouse cells.

Conditionally tumorigenic BALB/3T3 mouse cells (which produce tumors in BALB/c mice only under special conditions) cannot sustain DNA synthesis and consequently stop proliferating in media containing low concentrations (0-0.02 mM) of physiologically available calcium. By contrast, cells that have been neoplastically transformed (tumorigenic in mice without special assistance) in vitro by different oncogens, can sustain DNA synthesis and proliferate in such calcium-deficient media. The possible importance for tumor growth of an ability to withstand calcium deprivation is examined. It is suggested that this property may prove to be a reliable indicator of neoplastic transformation.