DNA-dependent RNA polymerase activities in hepatopancreas nuclei from Mytilus galloprovincialis Lamarck.

It has been shown that RNA synthesis in isolated hepatopancreas nuclei from Mytilus galloprovincialis is catalyzed by three DNA-dependent RNA polymerases (I, II and III) which resemble those identified in nuclei from mammalian cells. RNA polymerase I is active at 50 mM (NH4)2SO4, catalyzes the synthesis of GMP-rich ribosomal-like RNA and is completely resistant to the toadstool toxin alpha-amanitin. RNA polymerase II and III are active at higher (NH4)2SO4 concentrations, catalyze the synthesis of DNA-like RNA and are inhibited by very low (0.5-1 microgram/ml) and high (200 microgram/ml) concentrations of alpha-amanitin, respectively. Hepatopancreas nuclei retain considerable RNAase activity. Nuclear RNA polymerase activity may be underestimated since a part of the synthetized RNA is degraded.


Parent's presence and the child's response to dental stress.

The results of this study indicate that, given the option, most parents and children initially preferred to remain together during the child's dental visits. Although the percentage dropped as the series of dental visits continued, nearly half of the parents and children continued to prefer to remain together through the last visit. Although parents and children were free to choose, parents presence was not associated with a more negative response by the children. Further research in the complicated dynamics of the situation is needed.


Association between children's dental behavior and play behavior.

The results of this study showed that clinical distinctions can be made regarding the behavior of children in the dental setting and that these distinctions are reflected in the behavior of these children in an easily-arranged play situation. The existence of such associations of behavior presents the possibility that play behavior may be a reliable predictor of maladaptive dental behavior. If so, the incorporation of a play dental area into a dental office would be an inexpensive and convenient method of intercepting potential problem dental patients. If the results of this study can be replicated, they would support the initiation of a study to predict the behavior of children in the dental setting by means of easily scorable aspects of their play behavior in a simulated dental environment. Special management considerations could then be made to prevent disruptive behavior at subsequent appointments. The results also point up the tendency of problem patients to avoid certain aspects of the play dental experience. This suggests a possible treatment potential for the dental play area, using it as an instrument to desensitize appropriate patients to those aspects of dental treatment which distress them, and thereby reduce their anxieties, prior to actual dental treatment.


Vapor phase adsorption of water on hydroxyapatite.

Water vapor adsorption isotherms were determined gravimetrically on three hydroxyapatite sampel differing in preparation and with surface areas of 70.4, 22.5, and 3.0 M2/gm, respectively. Heats of adsorption for the first layer of water were found to be 13.3, 13.2, and 13.9 kcal/mole on these hydroxypatites. From repeated thermal desorption and adsorption cycles of water, stepwise adsorption was observed which diminished with each outgassing cycle until it disappeared after the fourth cycle. Cross-sectional area of adsorbed water molecule on hydroxyapatite surface was estimated at 11.5 A2. Standard free energies, isosteric heats, changes in enthalpy, and entropy of adsorption of water on HAP samples outgassed at 300 C were determined.


Canine transposition as autosomal recessive trait in an inbred kindred.

Three cases of bilateral transposition of maxillary canines with premolars were observed among eight siblings, Investigation of the sibship revealed consanguinity of the parents (cousins twice removed). Analysis of the extensive pedigree showed an hereditary pattern typical of autosomal recessive traits.


Determination of phase transitions in gutta-percha by differential thermal analysis.

Pure gutta-percha was heat-treated in a differential thermal analyzer. The high melting form crystallized on cooling when gutta-percha was heated to 70 C or less. Above 74 C, crystallization into the low melting form predominated. Either polymorph can be selectively crystallized by control of the heat-treatment temperature before cooling.


Amalgam containing nickel or tungsten dispersions. I.

Wetting tests were conducted to determine compatability between select dispersion powders and Ag3Sn. Subsequently, a method was perfected for incorporating nickel or tungsten powder into the Ag3 Sn ingot. Initial studies reveal good distributions of the dispersed phase in the ingots and the comminuted alloys, after amalgamation, appear to retain their normal working characteristics.


Amalgam containing nickel or tungsten dispersions. II.

The technique of injecting dispersed phase particles into an Ag-Sn melt followed by rapid quenching was utilized. Results of this investigation show that a marked improvement of the brittle amalgam alloy occurs.


Microstructure of dental amalgams containing high and low copper contents.

Microstructure of commercial dental alloys and their amalgams were studied primarily by x-ray diffraction, optical metallography, scanning electron microscopy, and x-ray energy dispersive spectroscopy. X-ray diffraction revealed more phases than normally reported in these materials. Presence of new phase was discussed and their formation mechanism understood. Some phases having interacting 2 theta degrees values with others were properly identified. Both new and conventional dental alloys and their amalgams, namely Tytin, Sybraloy, Dispersalloy, Kerr Spheraloy, Caulk Spherical, Shofu Spherical, and Caulk 20th Century Microcut were used to complete the investigation.


A study of oxidation of dental amalgams with age.

A quantitative test for corrosion due to oxidation has been accomplished. The oxygen concentration of dental amalgams was measured by fast neutron activation which provides a means of detecting oxygen in as small a quantity as 10 to 20 micrograms. An increase in oxygen content with age of spherical blend amalgam implants was observed, comfirming the importance of oxidation processes in in vivo corrosion.


Creep versus microstructure of gamma2-containing amalgams.

An analysis of the relationship between creep and microstructural characteristics of several gamma2-containing amalgams showed the grain size of the Ag-Hg phase (gamma1) to be a predominant factor influencing creep. When gamma1 grain size is increased, creep is reduced.


Dimensional changes of periodontal dressings.

The linear dimensional changes of three commercial periodontal dressings were measured during 24 hours. The dressings revealed different degrees of dimensional changes, which may indicate that exhibit variations in adaptation to wound surfaces.


Sealant effectiveness for children receiving a combination of preventive methods in a fluoridated community: two-year results.

A series of preventive methods in combination have been used to reduce dental caries in children including dental health education, prophylaxes, pit and fissure sealants, topical application of fluoride and restorative care. Prophylaxes, sealant, and fluoride procedures are repeated every six months. Two-year results show reductions of occlusal caries increments of 74.3% for first graders and 77.1% for sixth graders. Sealant loss, as defined in this study, varied from 33% to 90% with the highest loss occurring in the newly erupted permanent molars during the first six months of the project. These high sealant loss rates are thought to be related to the age of the population which was designed to include children at the ages of peak eruption of permanent molar teeth (ages six and twelve). These teeth were often only minimally erupted and maintaining the dry field required for sealant retention was extremely difficult. However, in spite of these high rates of sealant loss, caries reduction on occlusal surfaces was highly significant in comparision to that of children who did not receive sealants.


Fluoride levels in human parotid saliva following ingestion of fluoride compounds of varying solubility.

Healthy dental students received oral doses of 10.0 mg F daily in the form of compounds of widely varying solubilities. Parotid saliva F concentration and urinary F excretion were highest with NaF, Na2PO3F, and SnF2, lowest with CaF2, and intermediate with AlF3. Solubility of the ingested fluoride compound was a controlling factor in the amount of F excreted in the urine, the peak F concentration reached in parotid saliva, and the duration of a significant elevation in salivary F.


In vitro studies of the phenomenon of tetracycline incorporation into enamel.

Incorporation of tetracyline into dental enamels was studied by exposing presoftened enamel slabs to tetracycline-containing mineralizing solutions. Tetracycline was incorporated only when remineralization (assessed by hardness) occurred and the experimental conditions favored the formation of a soluble tetracycline Ca complex. The fluorescence induced by tetracycline incorporation into the enamel slabs was comparable to that reported under in vivo conditions.


Increased fibrinolytic activity in the inflamed gingiva of beagle dogs.

The fibrinolytic activity originated by activation of plasminogen was found to be greater in the inflamed gingiva than in the normal gingiva. The activator of plasminogen present in the normal and inflamed gingiva of the beagle dog was demonstrated histochemically. Plasminogen activator was found adjacent to the crevicular epithelium and blood vessels.


Electron microscopic evaluation of altered collagen structure induced by N-monochloroglycine (GK-101).

The effects of N-monochloroglycine (NMG) solutions on the structure of collagen were studied by transmission electron microscopy. In addition to finding that collagen structure was altered by NMG solutions, the results offer evidence that buffer and water also exert some effect on collagen fiber structure.


Effects of hibernation on interradicular alveolar bone.

The interradicular alveolar bones of the nonhibernating and hibernating ground squirrels were compared using light and transmission electron microscopy. During hibernation changes occurring in the bone suggest osteocytic osteolysis. Minerals may be mobilized from bone for utilization elsewhere in the body to maintain a minimal metabolic level for survival.


Osteodentin formation in continuously erupting teeth of guinea pigs.

Osteodentin formation in guinea pig teeth was studied using in vivo microscopic and histologic techniques. The coronal half of both incisors and molars contained varying amounts of osteodentin. Within the osteodentin, narrow canals that contained pulp tissue were observed. Serial histologic sections demonstrated that these canals opened to the occlusal surface thereby exposing the pulp to the oral cavity.


The effect of a magnesium deficient diet and cortisone on the growth of the rat incisor.

Incisors of Mg-deficient rats showed a marked inhibition of eruption and a decrease in mitoses of apical tissues. Cortisone administration resulted in some increase in eruption rate and cell division though these remained below the values of Mg-supplemented controls. An improvement in gross condition and a less severe histopathology of incisor tissues were also observed in cortisone-treated rats.


Alkylamine salts and amides: in vitro inhibition of S mutans 6715.

Our studies with the salts and amides of alkylamines have shown that the undecylenate salts have significant in vitro activity against S mutans No 6715, suggesting that these agents are worthy of additional evaluation. The attempt to increase activity by combining undecylenic acid with the alkylamines was not successful; however, better attachment to tooth surfaces and/or retention during washing did occur. Our results suggest that the free amino group of alkylamines and the free acid group of undecylenic acid are required for these two classes of agents to demonstrate antibacterial activity.


The antibacterial action of the various components of the lactoperoxidase system on a cariogenic strain of Streptococcus mutans.

Physiological activity of lactoperoxidase and in vivo concentration of thiocyanate ions were shown to be inhibitory against a cariogenic strain of Streptococcus mutans. However, the amount of H2O2 in vivo may be too low for optimum inhibition by lactoperoxidase system. H2O2 alone also inhibited the growth of S mutants to some degree.


Antibacterial effect of salivary peroxidases on a cariogenic strain of Streptococcus mutans.

The antibacterial effect of purified human salivary lactoperoxidase on a cariogenic strain of Streptococcus mutans was demonstrated while another oral peroxidase, probably of leukocytic origin, did not affect the growth. Lactoperoxidase was rapidly adsorbed by bacterial cells indicating the necessity of the contact between the enzyme and the cells before inhibition.


Relationship between the populations of Streptococcus mutans in the mouth and feces of conventional Sprague-Dawley rats.

The relationship between oral and fecal S mutans populations has been studied in rats fed high sucrose or glucose diet. All molar teeth were extracted either prior to or following oral challenge with strain 6715. In certain instances this procedure was supplemented with amputation of the incisors and disinfection of the remaining incisor surface area with iodine solution. The results suggest that in rats the colonization of S mutans on the teeth is required for its presence in the intestinal canal as well as the mouth. The significance of the observations has been discussed.


The effects of human saliva on the hemolytic activity of complement.

Human saliva was tested for the presence of factors that affect the complement system. Parotid saliva and salivary fractions were incubated at 37 C with human serum as a source of complement. Samples removed from the mixtures within the first 15 minutes had higher levels of whole hemolytic complement activity than did appropriate controls. The final ionic strength of the saliva-serum mixtures was critical to the hemolytic activity of complement. After 60 minutes all serum-saliva mixtures had lower levels of hemolytic activity than did serum-buffer controls. With regard to whole saliva, the salivary sediment was found to be strongly complement-reactive.


Comparison of 33P with 45Ca distribution in developing rat molar enamel in vivo and in vitro.

The distribution of 45Ca and 33P in developing rat molar enamel has been studied using freeze sectioning and autoradiographic methods. The distribution patterns of the two tracers in vivo were dissimilar. The use of in vitro methods showed that flux of 33P into enamel is not influenced by the cells of the enamel organ. It is suggested that the factors controlling movement of calcium and phosphorus into mineralizing enamel may be similar to those proposed for bone.


Isolation and characterization of epithelial and connective tissue cells from rat palate.

Epithelial and connective tissue cells were isolated from rat palate by sequential enzymatic digestion. Differences between the two populations were noted with respect to proline uptake and incorporation, % collagen synthesized, effects of parathyroid hormone and metabolism of D-valine. From these studies it can be concluded that the cell populations are viable and distinct with respect to the biochemical parameters examined.


Identification of N-methylated basic amino acids from human adult teeth.

NE-monomethyl-lysine, NG-NG'-dimethyl-arginine, and NG-NG-dimethyl-arginine from tooth protein fractions were identified utilizing thin-layer chromatography, amino acid analysis, and gas chromatography. It is suggested that a relationship exists between the presence of these N-methylated basic amino acids and the resting stage of tooth tissue.


Study on the biosynthesis of bovine enamel protein in vitro.

Biosynthesis of enamel protein was investigated by incubating bovine tooth germs with 3H-proline containing medium. The radioactivity was incorporated into two protein fractions: one had a molecular weight of about 25,000, being secreted from the ameloblast to the enamel matrix, another having a higher molecular weight was supposed to be a cell associated protein.


The seeded growth of calcium phosphates. The kinetics of growth of dicalcium phosphate dihydrate on enamel, dentin, and calculus.

The kinetics of growth of calcium phosphates on synthetic hydroxyapatite (HAP), human enamel, whole dentin, and human calculus has been studied at 37 C at pH values from 4.97 to 5.10 held constant by the pH-stat addition of base. Following an initial induction period, dicalcium phosphate dihydrate (DCPD) crystallization takes place on the surface of these solids in all cases, even though the solutions are highly supersaturated with respect to HAP. The second order crystal growth kinetics are characteristic of the crystallization of DCPD on pure DCPD seed material. The ability of the substrate surfaces to nucleate DCPD falls in the order, synthetic HAP greater than enamel greater than calculus greater than dentin. Nucleation of DCPD, which is completed during the initial induction period, is very sensitive to small changes in pH, from 4.99 to 5.10.


Rate of stannous fluoride reaction with hydroxyapatite.

Solutions of stannous fluoride are reacted with hydroxyapatite and the progress of the reaction is monitored by calcium analysis. The formation of Sn3F3PO4 proceeds faster with an increase in SnF2 concentration and can be further increased by adding Sn++ to the stannous fluoride solution.


Corrosion and creep of dental amalgam.

The influence of stress on corrosion was investigated by a potentiostatic technique. Amalgrams with low creep, both with and without gamma2-phase, revealed small increases in current with stress application while alloys with high creep exhibited large increases in current. Rupture of protective oxide due to increased strain for high creep alloys may explain the phenomenon.


Changes in consistency of occlusal contact in myofascial pain-dysfunction (MPD) syndrome.

The sound patterns produced by tooth contact were recorded in 24 subjects with myofascial pain-dysfunction (MPD) syndrome prior to and following treatment using an Occlusograph. Recordings also were obtained on 12 control subjects. Evaluation of the sound patterns showed a close correlation between the improvement in symptoms of MPD syndrome following treatment and the consistency of repeated occlusal contacts. The consistency following successful treatment of the subjects with MPD syndrome was equivalent to that of the control subjects.


Electrical resistance correlation with tactile examination on occlusal surfaces.

Electrical resistance of the tooth was measured through the dental pulp by a relatively simple method. The primary resistance is in the enamel, and the total resistance drops severalfold as dental caries develop. This resistance has been measured on the occlusal surfaces of 122 teeth of children. The differences between explorer categories showed statistically different resistance values (P greater than 0.9995, excluding the offscale sound-tooth category). After 3 to 4 months, 9 of the 32 teeth of the incipient caries category became obviously carious, while none of the caries-free teeth became carious.


Thermal analysis of dental impression waxes.

Ten dental impression waxes were characterized by penetration and differential thermal analysis. Penetration and initial transition temperatures were directly correlated. Penetration at 37 C ranged from 2.5 to 22% for bite waxes and was 100% for corrective waxes. Distortion of an impression wax may occur upon removal from the mouth.


Alterations in lactoferrin in salivary gland disease.

During the active phase of chronic recurrent parotitis there is a marked elevation in the parotid concentration of lactoferrin (Lf), and iron-binding glycoprotein with antibacterial properties. The Lf concentration decreases during the recovery period, but still remains above normal levels. The changes of Lf in parotitis parallel recent findings in mastitis and pancreatitis. Elevations in Lf were also noted in five of six subjects with Sjögren's disease, but not in subjects with sarcoidosis, diabetes or "dry mouth" without sialographic changes. The source of the Lf has not been determined; it could arise in part from disrupting polymorphonuclear leucocytes and in part from epithelial cells that synthesize Lf in the salivary glands. Inflammatory stimulation of Lf synthesis would suggest a basic protective mechanism in exocrine glands and should be fully explored.


The sensory mechanism in human dentin as revealed by evaporation and mechanical removal of dentin.

Dentinal pain in connection with mechanical stimulation i.e. probing, chiseling and initial drilling may be due to removal of fluid from the dentinal tubules. Loss of fluid due to "normal" evaporation from exposed dentin may produce an outward flow in the dentinal tubules rapid enough to cause pain and within a few minutes odontoblast aspiration.


Relationship of strontium in drinking water and surface enamel.

The Sr content of surface enamel of 233 teeth from nine communities was related to drinking water Sr concentrations. These water concentrations ranged from 0.02 microgram/ml to 33.9 microgram/ml. The relationship between enamel concentrations and water concentrations was linear for water concentrations less than 10 microgram/ml Sr, but leveled off at approximately 300 microgram/gm Sr in the enamel for communities with greater than 10 microgram/ml Sr in drinking water. Binding of Sr to components in the oral environment is proposed as an explanation of this effect.


Effect of perceived control on stress reduction in adult dental patients.

A signaling device was given to adult patients to reduce stress in the dental chair. Galvanic skin response during the dental procedures indicated that patients with the signaling device showed more arousal during high stress conditions when compared with a control group. A personality variable was also investigated.


Dentin permeability: changes produced by iontophoresis.

Iontophoretic currents (0--1.0 mA) were applied to dentin disks prepared from human third molars. A negative electrode increased 125I-permeation 10X, while a positive electrode increased 14C-lidocaine 8X. Iontophoresis appears promising as a method to increase the permeation of dentin by ionized substances of therapeutic interest.


Effects of indomethacin upon 131I uptake by thyroid and submaxillary glands in mice.

The administration of indomethacin to male A2G mice induced a marked decrease in the 131I uptake by the thyroid, but it did not influence the 131I uptake by the submaxillary glands.


Regulation of the secretory process of granular components from the convoluted tubular cells of the mouse submandibular gland.

Autonomic regulation of the secretion of granule components in the convoluted tubular cells of male mouse submandibular glands was investigated with the use of an agar gel diffusion test using an antisera for male specific components. Whereas the injection of neither a parasympathomimetic agent (pilocarpine) nor a beta-adrenergic agent (isoproterenol) decreased the amount of the components in the glands, the injection of alpha-adrenergic agents (norepinephrine or phenylephrine) significantly decreased the amount of male specific components. Phenoxybenzamine, an alpha-blocker, completely inhibited these actions of norepinephrine and phenylephrine. These facts suggest that the alpha-adrenergic receptor participates in the secretion of male specific components present in the granules in the convoluted tubular cells of mouse submandibular glands.


Studies on hemolytic activity of bisphenol A diglycidyl methacrylate (BIS-GMA).

To clarify the high hemolytic activity of BIS-GMA, the molar concentration producing 50% hemolysis (H50) and the partition coefficient inoctanol-water were determined using BIS-GMA and various types of methacrylates. It is suggested that the strong hemolytic potency of BIS-GMA is due to the high hydrophobic nature of the compound.


Antibacterial activity of tooth-colored dental restorative materials.

The antibacterial activity of dental restorative materials (12 resin based and one silicate) was tested in vitro against 5 species of bacteria. When fresh, all materials inhibited growth in pour plates of at least one bacterial strain. After storage in saline for 24 hours, the antibacterial activity was markedly reduced. There was a wide variation among the materials in the extent of their antibacterial activity. The bacterial strains apparently differed in their susceptibility to the antibacterial activity of the materials.


Effects of an antiseptic mouthwash on odorigenic microbes in the human gingival crevice.

Odorigenic gram-negative anaerobes in human gingival crevices were significantly decreased for up to 120 minutes after rinsing with an antiseptic mouthwash. This observation parallels clinical measurements of the antiseptic effect on oral malodor and suggests that its odor-decreasing properties are related to its antimicrobial action in the mouth.


Dentin permeability: determinants of hydraulic conductance.

A technique is described which permits measurements of the ease with which fluid permeates dentin. This value, the hydraulic conductance of dentin, increased as surface area increases and/or as dentin thickness decreases. It increased 32-fold when dentin was acid etched due to removal of surface debris occluding the tubules.


Volunteering in dental peer review: differences between volunteers and practitioners at large.

This report characterizes differences among early and late volunteers, and non-volunteers for personal characteristics and situational determinants of volunteering in an experimental dental peer review study. Differences were found for volunteers/non-volunteers for some items representing subject interest, expectation of a favorable evaluation, sociability, and achievement motivation.


Incidence of torsiversion in mandibular third molars.

Two percent of 826 adults examined during routine dental check-up visits show torsiversion in their molars. The degree of rotation ranges from 20 degrees to 60 degrees with the predominant position at 30 degrees buccal. This condition is quite rare and appears to be genetically directed at the infracrypt level of development.


Metal-filled resin composites. II.

Various particulate materials were combined with a BIS-GMA resin, and the resulting composites were evaluated. The fillers prevented, altered, had no apparent effect, or accelerated polymerization. Coupling agents also influenced polymerization. Physical properties varied widely with different fillers.


The rheological characteristics of elastomeric impression materials.

An indirect extrusion viscometer has been used to assess the shear rate dependence of viscosity of a range of pastes supplied for elastomeric impression materials. A suggested specification for these pastes has been proposed.


The rheological properties of fluid denture-base resins.

The rheological properties of six commercial fluid denture resins were determined by rotational viscometry. Initial viscosity ranged from 67 to 575 centipoise at a rotational speed of 10 revolutions per minute. All resins showed initial non-Newtonian flow behavior and increased viscosity with time.


Infrared spectroscopic studies on the development of crystallinity in dental zinc phosphate cements.

An infrared spectroscopic study has been made of the development of crystallinity (hopeite) in dental zinc phosphate cements. Crystallization in the bulk of a cement is prevented only by the incorporation, in the liquid, of aluminum which forms complexes with phosphoric acid. The development of surface crystallinity is related to the chemical composition of the cement and the speed of the reaction. No acid phosphates are to be found in the matrix which consists solely of neutral orthophosphates.


Effect of surface preparation on phase distribution of amalgam surfaces.

Several types of amalgams were prepared with carved, burnished, or polished surfaces. Elemental analyses were made of these surfaces with the electron microprobe and the phase fractions were calculated from these data. The phase distributions were found to vary with the technique of finishing.


Estimation of the phase distribution in dental amalgam with the electron microprobe.

The phase distributions of several dental amalgams have been determined by two methods: calculation from elemental analysis data obtained with the microprobe, and measurement of phase areas on backscattered electron photographs with the image analyzer. The results of these methods agree, in general, with the distributions predicted by the stoichiometric equations.


Objective evaluation of surface microreplication by dental impression materials.

Twenty-two materials, including 19 dental impression elastomers, were compared in their ability to replicate microscopic detail. Some polysulfide, silicone, and polyether materials performed well. Curiously, microscopic replication ability generally correlated inversely with that expected from the nominal consistency. The test method developed appears to be a suitable microreplication evaluation standard.


Pre-apatitic mineral deposition in Bacterionema matruchotii.

A preliminary examination of calcification of Bacterionema matruchotii was undertaken to provide a base-line for future kinetic and mechanistic studies. Specific ion ratios were correlated with crystallography and ultrastructure. Observations include: three consistent X-ray diffraction patterns; no resolution of cellular EMP by electron microscopy; increasing Ca/Mg, Ca/P during calcification.


Fluorine and tin uptake by enamel studied by x-ray photoelectron spectroscopy (ESCA).

ESCA has been combined with argon-ion etching to obtain depth profiles for SnF2-treated enamel. Three zones of products from the topical treatment are detected: a layer of tin oxide on the surface; fluoroapatite + hydroxyapatite at depths below about 0.2 micron; an intermediate layer CaF2, Sn(OH)2, Sn2PO4OH, and fluoroapatite between the two. Sn3F3PO4 was not detected.


Influence of the pulpal route on uptake of 45Ca in enamel and dentin of developing rat molars.

45Ca uptake in developing enamel and dentin was studied by autoradiography. The findings indicate that the pulpal route does not supply significant amounts of calcium to the rapidly mineralizing enamel. Disruption of the odontoblastic layer did not seem to result in altered penetration of calcium into the dentin in a manner similar to that described for disruption of the matrix secreting cell layer of enamel and of bone.


Evidence for the presence of carbamino compounds in human saliva.

The bicarbonate concentrations of whole saliva and of protein-free filtrates of saliva were measured to test for the presence of carbamino compounds. If no acid-evolved CO2 were derived from the salivary proteins, then the two measured bicarbonate concentrations should be identical. Instead, the bicarbonate concentrations of the whole saliva samples were on the average 30% higher than that of their filtrates. The results are consistent with the conclusion that carbamino compounds account for the differences. Similar findings were obtained with samples of resting whole saliva and parotid saliva.


Metabolism of gingival collagen in a rat.

The remodeling of gingival tissue was measured by determining the incorporation of tritiated proline and the disappearance of tritium activity from proline and hydroxyproline for 18 days after administration of label. There was a rapid decrease in the tritium activity from gingiva which was paralleled by a decrease in the total activity of proline. The activity in collagen decreased sharply between the second and the fourth day but thereafter there was no change. The relative amount of activity increased from 24% at day 2 to 82% at 18 days postinjection, and as a result the specific activities of hydroxyproline and proline were similar after 12 days. Thus collagen appeared to be the more stable component in the gingivae than previously reported. However, the rapid loss of label in the first four days suggested that there may be very marked regional variation in the metabolism of collagen and that more than one metabolic pool of collagen was present.


Semiconductor probe measurements in beagle dogs with periodontal disease.

A miniaturized semiconductor probe was used to measure alveolar bone uptake of a bone-seeking radiopharmaceutical in dogs with destructive periodontal disease. Radiopharmaceutical uptake in localized, advanced disease was greater than in incipient disease and was generalized, with increased uptake occurring in radiographically normal areas and in areas with bone loss.


Influence of hexetidine upon plaque and gingivitis in the beagle dog.

Two studies were performed in beagle dogs to determine the effect of 0.2% hexetidine upon plaque and gingivitis. In both instances, hexetidine exerted no significant effect while 0.2% chlorhexidine resulted in reductions in both plaque and gingivitis of about 45 and 50%, respectively.


Antimicrobial agents and dental caries in the rat.

Two rat plaque-caries studies indicated that a 0.2% chlorhexidine solution topically applied to rat teeth was effective in reducing dental plaque. This reduction in plaque was accompanied by marked reductions in smooth surface caries, but not in sulcal lesions.


Sources of variability in rat caries studies: microbial infection and caging procedure.

Two sources of variability in rat caries experiments have been investigated: infection with two S mutans strains and two types of caging. Results indicated that strain 6715 was more virulent than was strain 10449 when 24-day-old rats were orally infected with the organism under standardized conditions. Caging of rats (2 per cage) in stainless steel, raised bottom cages resulted in higher level of caries than in plastic tubs (3 per cage) with hardwood bedding. Infection and caging conditions are two of the factors which may contribute to variability in caries pattern and severity in experimental rats.


Transmembrane potentials of osteoblasts.

Transmembrane potentials were recorded in situ from osteoblasts on the parietal bones of albino rat pups, 3 to 24 days of age. Osteoblasts exhibit a uniquely low polarization of their cell membranes (3.93 mV, inside negative). Osteoblasts respond rapidly, but transiently, to parathyroid hormone by depolarization, and to thyrocalcitonin by hyperpolarization.


The effects of cadmium on the growth of some oral microorganisms and their ability to bind cadmium.

All seven oral Actinomycetaceae tested grew in broth containing 10 microgram/ml Cd. After 24 hours' growth A viscosus WVU 626 bound nearly 20 microgram Cd/mg dry wt. The amount of Cd bound varied during the growth cycle, being maximal (90 to 100 microgram/mg dry wt.) after 5 hours' growth. Addition of 50 microgram/ml chloramphenicol to actively growing cells inhibited further Cd binding. In contrast S mutans FA1 was greatly inhibited by 2.5 microgram/ml Cd and bound only 1.3 microgram Cd/mg after 24 hours' growth in broth containing 2.5 microgram/ml Cd.


The effect of some divalent cations on extracellular polysaccharide synthesis in Streptococcus salivarius.

The amount of extracellular insoluble polysaccharide produced by Streptococcus salivarius can be effected by some divalent cations. Calcium at concentrations of 1 X 10(-3) and 10(-4) M caused a reduction in polysaccharide synthesis. Magnesium at 1 X 10(-3) M inhibited extracellular polysaccharide production but at 1 X 10(-4) M had little effect. Manganese was without effect on polysaccharide synthesis. Zinc at 1 X 10(-3) and 1 X 10(-4) M caused a substantial increase in extracellular polysaccharide synthesis.


Experimental formation of "corn cob" in vitro.

Organisms isolated from corn cob were examined for aggregation with Bacterionema matruchotti. Such aggregations, interpreted as corn cob formation, in vitro, occurred with five isolated identified as Streptococcus sanguis. A cell-surface component of Streptococcus sanguis or a phospholipid-related substance of Bacterionema matruchotii appeared to be involved.


Effects of craniofacial structures on mouse palatal closure in vitro.

Heads of Swiss-Webster mouse fetuses of four ages spanning days 12-13 of gestation, were partially dissected by removing the brain (B), tongue (T) and mandible (M) alone or in combination (BT, BM, BTM). Preparations were suspended in a gassed, circulating culture system such that palatal closure must take place against gravity. Closure occurred earlier than in vivo and required the posterior half of the mandible be intact and the tongue removed.


Diet-induced arteriopathies in the rabbit aorta and oral vasculature.

Advanced atherosclerosis in the form of fibro-fatty intimal plaques has been produced in the rabbit aorta and oral vasculature (labial, lingual, gingival, palatal, periodontal and alveolar arteries) by dietary means. The animals were fed a hypercholesteremic diet and a normocholesteremic diet on alternate months for two years. In the aorta and in many of the oral vessels, the formation of the intimal atheromas was paralleled by a degeneration of the tunica media. The lingual arteries rivaled the aorta and coronary arteries in vulnerability to the diet-induced arteriopathies.


Plaque minerals and caries experience: associations and interrelationships.

Inverse associations were demonstrated between DMFT and total calcium, phosphorus, magnesium, strontium, potassium, and fluoride concentrations in individual plaques. Lithium, strontium, fluoride, and zinc contents were inversely related to plaque mass. Consistent interdependence patterns between elements indicate the operation of a mineral level regulating mechanism, effective under diverse environmental conditions.


An epidemiologic study of the relationship between various states of occlusion and the pathological conditions of dental caries and periodontal disease.

This study explored relationships between dental caries and periodontal disease and either (1) any of 8 existing orthodontic indices or (2) any of 41 individual cephalometric measures. The 486 subjects examined revealed no clinically significant associations between any of the disease measures and either the indices or the cephalometric measurements.


Enamel dissolution by various food acidulants in a sorbitol candy.

The carboxylic acids used as food acidulants were evaluated for their effect on enamel dissolution in vitro. In water, the potential of the food acids to demineralize enamel was directly proportional to their acidity. However, in a sorbitol candy, the amount of enamel dissolution was correlated with the potential of the acids to chelate calcium.


Dental caries and socioeconomic status in Mexican children.

A dental caries survey of 2,445 Mexican children, 6 to 15 years of age, was conducted in an industrial city. The children were divided into three socioeconomic groups. The pattern of the caries attack rate conformed to all caries surveys. However, the DMFT and DMFS scores increased as the socioeconomic levels increased. The higher socioeconomic groups presented evidence of more dental care than the low group.


The Aymara of western Bolivia: III. Occlusion, pathology, and characteristics of the dentition.

With the objective of contributing to the understanding of factors influencing the characteristics of dentition, dental observations from 429 children and adult highland people of western Bolivia are described. Various age, sex, ethnic, and village differences are observed in malocclusion, dental caries, periodontal disease, dental morphology, and anomalies. The findings revealed a population with relatively good occlusion, low frequency of dental pathology, and dental characteristics in part consistent with those of other similar Amerindian populations.


Wet weights of dental plaques.

A method for weighing samples of plaque using a weighing assembly comprising a sample-bearing boat, held in a closed capsule to avoid moisture loss to room or balance environment is described. The system described is an objective device for measuring, by wet weight the amounts of plaque accumulating under various conditions of oral hygiene.


Psychological characteristics of long-term female temporomandibular joint pain patients.

Analysis from the Taylor Manifest Anxiety Scale (TMAS) scores of 44 long-term temporomandibular joint (TMJ) pain patients and 10 facial pain patients of a non-TMJ variety shows no significant differences. Both groups were significantly higher than a normative group. After treatment TMJ patients are not significantly different on the TMAS than the normative group. Etiological implications are discussed.


Measurements of cervical undercuts of human tooth crowns.

The dimensional factors of the cervical undercut of the human teeth were measured. The facial and lingual undercuts showed considerable deviations in depth, width, and inclination to the crown axis and the food stream. The proximal undercuts showed a uniform depth of 1 +/- 0.3 mm with some deviations in width and inclination.


Aldehyde methacrylates derived from hydroxybenzaldehydes.

Three crystalline aldehyde methacrylates with low melting points were synthesized from the readily available, isomeric hydroxybenzaldehydes and 2-bromoethyl methacrylate. These monomers can be purified by recrystallization and liquified by admixture in various proportions to obtain polymerizable liquids having workable viscosities at room temperature. These monomers may be used alone or as blends with other methacrylates since they are miscible and copolymerizable with the usual dental monomers. Also, they should be studied with other functional methacrylates designed to promote adhesion via the mineral phase to determine if this synergistic approach can improve the adhesion of dental resins to dentin. These aldehyde methacrylates, their mixtures, polymers and copolymers merit evaluation as adhesion-promoting agents for proteinaceous substrates such as bone and dentin.


Confirmation that neither phenotype nor hydroxylation of collagen is altered in overgrown gingiva from diphenylhydantoin-treated patients.

Collagens, solubilized by pepsin-digestion of diphenylhydantoin-induced overgrown gingiva, appeared similar to collagens solubilized from inflamed gingiva with regard to: ratio of type I to type III collagen, ratio of alpha1 to alpha2 of type I collagen, and degree of hydroxylation of type I collagen.


Mineral and collagen fiber orientation in human secondary osteons.

Scanning electron microscopy and x-ray microdiffraction studies were conducted on single isolated osteons appearing "bright," "dark" and "intermediate" under crossed polaroids and the orientations of collagen fibers and crystallites within them determined.


Fluoride uptake and caries rate in hamster molars after topical fluoride application followed by acidulation.

Daily topical application of 2% NaF on hamster molars for 4 days in vivo, followed by acidulation (grapefruit beverage, pH 3.3) resulted in a lower caries rate than NaF followed by water application. Fluoride uptake was somewhat higher, but not significantly so in the acidulated group.


Comparing the effectiveness of the mini-lecture technique to role-playing in a dental psychology course.

The array of instructional methods utilized in teaching behavioral sciences to dental students has included both teacher-centered and student-centered approaches. The purpose of this study was to evaluate the effectiveness of two small-group treatments, mini-lecture and role-playing, in teaching dental psychology. Freshman dental students were randomly assigned to 12 groups. Groups were then assigned to one of six dentist-pyschologist teaching teams so that each team taught one mini-lecture and one role-playing group. Teaching teams taught seven sessions in which each mini-lecture/role-playing pair of groups received parallel subject matter. Following instruction, two outcome measures were administered: (1) an achievement post-test measuring factual recall, and (2) a measure of facilitative communication. Results indicated that mini-lectures were more effective than role-playing in effecting student mastery of factual information. There were no significant differences between the instructional treatments in teaching facilitative communication skills.


Acquisition of psychomotor skills in tooth preparation using self-paced instruction.

Self-paced instruction whereby students are provided with learning resources and allowed to learn at their own rate--with or without assistance from instructors--is increasingly being used in dental education. The wide diversity of entering dental student experience with psychomotor tasks suggests that preclinical psychomotor skill development should adapt well to self-paced learning. This study compared self-paced instruction to traditional preclinical teaching of psychomotor skills in cavity preparation. Performance by the self-paced class was significantly better than that of the traditional class on two procedures. There were no significant differences among the other procedures tested.


Improved reliability of dental radiography by application of x-ray beam-guiding instruments: a two-year report.

Demands on dental practitioners for documentation of patient needs plus evidence of high rates of inadequate radiographs in teaching and practice reveal a need for accurate, simplified radiographic techniques. New procedures using X-ray beam-guiding instruments were used for all periapical films in a clinical teaching program. Data collected over two years showed a high procedural reliability with these instruments. The film quality and low retake rate may have been due to the beam-guiding effect that also assures minimum patient exposure to radiation. Since beam-guiding instruments may also reduce the time expenditure in teaching and practice, the proposed procedures may be able to provide better radiography for less expense.


Effectiveness of preventive dentistry delivery system.

A preventive dentistry delivery system was developed for maximum effectiveness in private practice. Four new pit or fissure carious lesions developed in 20 patients who were 10 to 20 years old at the start of a two-year exploratory test; there were no new lesions of smooth surfaces. Of the incipient lesions that were under observation, no increase was observed in 23 of 26 pit or fissure lesions, 24 to 25 proximal and all of 26 buccal or lingual smooth surface lesions. In 33 patients 21 to 30 years old at the start of the test, no new lesions appeared and growth of the 142 incipient lesions appeared to be arrested. A low level of gingivitis was maintained in all patients who were tested.


Indirect pulp-capping of carious teeth with periapical lesions.

Twenty-four vital teeth with deep carious lesions associated with radiographically demonstrable periapical lesions were treated conservatively by means of the indirect pulp-capping technique. Eleven teeth showed apparent resolution of periapical pathology, an absence of pain, and continued vitality when followed up as long as seven years postoperatively.


Ownership and maintenance of dental records.

The maintenance of good dental records is essential for the defense of a professional liability claim. If a dentist must give records and radiographs to a patient, insurance carrier, or succeeding practitioner, he should always give copies and maintain the originals. As a professional liability claim can often be filed long after treatment ceases, the dentist should retain his records permanently. The right of a patient to gain access to his medical or dental records has been granted by recent court decisions as well as by laws and regulations enacted in some states. The court decisions granting a patient access to his records are law in the jurisdictions in which the cases were decided. However, those decisions would present persuasive authority in a stage having no case law or statute regarding access by the patient to medical or dental records. The dentist should consult his attorney to determine the local law before allowing a patient access to his records and radiographs.


Root canal morphology of mandibular premolars.

Four hundred mandibular first premolars and 400 mandibular second premolars were decalcified, injected with dye, and made transparent to determine the number of root canals, their type, the ramifications of the main root canal, the location of apical foramina and transverse anastomoses, and the frequency of apical deltas. The mandibular first premolar had one canal at the apex in 74.0% of the teeth, two canals at the apex in 25.5%, and three canals at the apex in 0.5% of the teeth. The mandibular second premolar had one canal at the apex in 97.5% and two canals at the apex in 2.5% of the teeth.


The two-in-one, self-threading, self-shearing pin: efficacy of insertion techniques.

An in vitro study has shown that the TMS minim two-in-one, self-shearing pin reaches maximum depth in a 2-mm pin channel before shearing off with insertion by a hand-turned wrench. The self-shearing, two-in-one pin did not achieve the full channel depth of 2 mm with insertion by an Auto Klutch handpiece.


Preliminary study of changes in blood pressure associated with clenching in normotensive and hypertensive subjects.

This study was undertaken to test the effect of static, empty-mouth clenching on blood pressure levels in normotensive and hypertensive subjects. Blood pressures were measured before, during, and after one minute of empth-mouth static (isometric) clenching in 41 normotensive (group A) and 22 hypertensive subjects (group C). An additional group of 13 normotensive subjects (group B) were examined for elevations in blood pressure before, during, and after 30 seconds of clenching. Subjects in group A showed a clenching-related increase in mean arterial blood pressure of 5.5 mm Hg (P less than .001); in group C, there was an increase of 4.6 mm Hg (P less than .001); and in group B, there was an increase of 3.2 mm Hg (P less than .05). The results emphasize the relationship between isolated dental treatment and systemic health.


Combined surgical procedures to correct facial deformities.

Combined maxillary-mandibular surgical procedures to correct facial deformities raise problems not usually seem when correction is limited to one arch. When multiple procedures are contemplated, it is easy to lose the relationship of theocclusion to the proposed facial contour. Model surgery is the key to determining the correct surgical site. Conflicting requirements of staging, flap design, and fixation often arise. Six maxillary-mandibular combined correction procedures that required exact diagnosis and careful planning have been presented. Explanning have been presented. Excellent long-term results were gained in each case.


Barodontalgia at 12,000 feet.

Persons susceptible to barodontalgia include those with peridontal abscesses, carious teeth, maxillary sinus congestion, or those who have had recent extractions or restorations. A 38-year-old man had acute pain while he was in a depressurized chamber. Treatment of a periodontal abscess alleviated the problem.


Leukemia: the dentist's role in diagnosis.

Patients with leukemia frequently have oral signs and symptoms that may lead to the early diagnosis of this condition. Hematologic laboratory tests that would be of value include a white blood cell count and a platelet count. The dental practitioner should be aware of those diagnostic signs and the possibilities of oral complications associated with the disease. The nature of leukemia and its complications require a regular and thorough oral examination as part of the routine treatment of these patients.


Impact of a computerized placement service on practice location of recent graduates.

In 1972, the University of Minnesota, the Minnesota Dental Association, and the State Board of Dentistry implemented a program known as the Dental Information Service Center. An important component of this effort was a set of computerized programs aimed at facilitating placement of recent graduates of the University's dental school. Although use of the computerized program has grown substantially during the four-year study period, personal contacts remain the source of information most frequently responsible for initial placements; they accounted for 60% of such placements. The computerized referral program accounted for 27% of first placements for the class of 1976. The program has been influential in increasing student awareness of underserved areas. Overall career satisfaction was high among recent graduates, and their subjective evaluation of the program was generally positive.


Effect of school water fluoridation on dental caries: results in Seagrove, NC, after eight years.

In 1968 at Seagrove, NC, fluoride was added to the water supply of a rural school (grades 1 through 12) at a level of 6.3 ppm, seven times the optimum level recommended for community water fluoridation in the area. Findings after eight years showed that children in grades 1 through 8 had approximately 40% fewer DMF surfaces than did their counterparts on the baseline. A comparison of these findings with those of another school fluoridation study, in which a level of 4.5 times the optimum concentration had been tested, showed only a slight advantage to the children at Seagrove. However, the full potential of school water fluoridation at seven times the optimum level cannot be determined until children in all grades will have been exposed since entering the first grade.


Microscopic observations of amalgams carved by different methods and subsequently polished.

Occlusal amalgam restorations placed in extracted deciduous molars were studied using an electron microscope. The fillings were carved only or both carved and burnished, and all were subsequently polished. Observations were made before and after polishing, and the results emphasized the effects of carving, burnishing, and polishing on the surface texture and marginal integrity of amalgam fillings.


A study of the long-range effectiveness of teaching blood pressure screening in a dental college.

The University of Tennessee College of Dentistry has been actively involved in teaching the fundamentals of blood pressure screening since 1964. To determine the effectiveness of this instruction a sample of practitioners who have graduated since 1964 was surveyed to determine the degree to which they use blood pressure screening in their practices.


Treating electrical burns of the mouths of children.

Electrical burns of the mouth can result in severe scarring and constriction of the lip commissures. Plastic surgery is needed to correct this defect when a special burn obturator is not used. The obturator is worn for a year and can prevent or reduce the need for corrective surgery.


Timing and sequence of eruption of permanent teeth in a longitudinal sample of children from Oregon.

A longitudinal sample of children was examined for timing and sequence of eruption of permanent teeth. Separate consideration was given to 124 boys and 163 girls from the Child Study Clinic longitudinal growth study. Girls show more variability in age at eruption than boys, and eruption is generally earlier in girls. The degree of variation in sequences of eruption of the first seven permanent teeth is distinct. The most common sequence in girls' maxillas occurred in only 11.4% of subjects; in boys, the most common sequence appeared in 13.4% of subjects. Predictability efficiency of eruption of the first three permanent teeth is not higher than 0.74.


Oral slough caused by dentifrice detergents and aggravated by drugs with antisialic activity.

A unusual type of oral desquamation appeared as grayish-white gelatinous membranes on the floor of the mouth, lips, vestibules, and gingiva in a 50-year-old woman. The painless desquamation was caused by synthetic dentifrice detergents (foaming agents) and was exacerbated by the patient's use of drugs with antisialic action.


Cementoenamel defects in an unusual location.

An unusual case involving cementoenamel defects was discussed. These defects appeared as vertical grooves at the cervical margins on the facial surfaces of the maxillary incisors. They have caused no pulpal or periodontal problems.


Senior residents' opinions about oral surgery programs.

A questionnaire for senior oral surgery residents was distributed to elicit their opinions about various phases of their oral surgical training. Of 206 questionnaires sent to members of house staffs in approved programs, 122 responses (59%) were received. The average senior resident felt well prepared in exodontia, trauma, and orthognathic surgery. He considered himself much less prepared in pediatric oral surgery and tumor management. The average resident believed oral surgery was well regarded and would again choose his own program for training.


The surgical sequence of combined total maxillary and mandibular osteotomies.

In many instances, orthognathic surgical cases require multiple osteotomies in the maxilla and mandible to achieve the most desirable result. When the entire maxilla and mandible are freed from their relationship with the remaining craniofacial complex, accurate repositioning and adequate stabilization can present problems. These problems can be minimized by operating in the proper sequence or by staging the procedure. Staging should be considered for the more complicated cases; in any instance, the maxilla should be operated on first.


Implant of articular eminence for recurrent dislocation of the temporomandibular joint.

Hypermobility of the temporomandibular joint is often caused by trauma, by opening the mouth too wide, by having a mouth forced open during general anesthesia procedures, or by dental procedures. The capsule may be stretched to an extent that dislocation occurs more easily thereafter. An implant of Vitallium mesh attached to the zygoma to restrict anterior movement of the condyle is used to prevent recurrent dislocation of the temporomandibular joint.


Antibiotic suseptibility of bacteria isolated from oral infections.

Exudates from bacterial infections of oral soft tissues were cultured and tested for antiobiotic susceptibility. Of 74 specimens tested, 68 were cultivable on blood agar; 56 of the cultivable exudates were pure cultures and 12 were mixed cultures. Strepococci and staphylococci accounted for 57% and 34%, respectively, of the pure cultures. Anaerobic bacteria were found in nearly 15% of the pure culture exudates. Gramnegative organisms accounted for about 4% of the pure cultures. Virtually all of the pure and mixed streptococcal cultures were sensitive or moderately susceptible to ampicillin, cephalothin, and penicillin; however, approximately 50% of the streptococal and staphylocococcal isolates were resistant to demeclocycline hydrochloride and erythromycin.


Microscarring in skeletal muscle after repeated exposures to lidocaine with epinephrine.

To assess the effect of repeated exposures to clinically used local anesthetic, rat thighs were given up to five supramuscular injections of 2% lidocaine with epinephrine, 1:50,000. Substantial damage to muscles followed by rapid regeneration occurred; however, in some areas evidence of retarded regeneration of muscles and microscarring was observed.


Posttraumatic thrombotic occlusion of the internal carotid artery: report of two cases.

Two cases of posttraumatic thrombosis of the internal carotid artery are reported. Etiological theories are discussed and the relevance of the disorder in the assessment of facial injuries is emphasized.


Internal carotid artery thrombosis associated with a fracture.

A case of occlusion of the internal carotid artery after craniocervical trauma with subsequent death of the patient is presented. The patient originally had a mandibular fracture; subsequently an altered sensorium and left-sided hemiparesis developed. The patient died. The typical "lucid interval" was noted. The changes in sensorium are similar to those associated with epidural and subdural hematomas.


Multiple myeloma involving the temporomandibular joint: report of case.

A case of multiple myeloma was reported in which the initial symptom was pain and dysfunction of the TMJ that resulted from pathological fracture of the mandibular condyle. An initial radiographic skeletal survey showed no evidence of further lesions, although hematological and biochemical tests indicated a diagnosis of multiple myeloma. Treatment resulted in improvement of symptoms and of an evident regression of the lesion after 18 months. After a year, however, radiographs disclosed generalized skeletal involvement; deterioration of the general condition followed.


Oral manifestations of acute promyelocytic leukemia.

A study was conducted of 16 patients with acute promyelocytic leukemia. The most common oral manifestations were hemorrhagic diathesis and leukemic involvement. There was gingival bleeding, petechiae, and ecchymosis of the oral mucosa, massive infiltration-induced gingival swelling, ulcerative glossitis, swelling of the tonsils, and facial palsy. Inflammatory stomatitis also occurred. Patients with acute promyelocytic leukemia had a higher incidence and severity of oral bleeding than those with other types of acute leukemia. However, the oral findings in our series were not necessarily specific for acute promyelocytic leukemia because the same oral symptoms occur in other forms of acute leukemia.


Survey of experiences with the mandibular staple bone plate.

The mandibular staple bone plate has been used to reconstruct the atrophic or deformed mandible in more than 400 cases. A survey was undertaken to evaluate those cases; results indicate that 90% of patients have satisfactory function.


Follow-up study of palatal graft donor sites in 24 patients.

The palatal mucosal graft donor sites of 24 patients were examined several months after surgery. In all but two patients, the donor sites were asymptomatic.


Pilomatrixoma (calcifying epithelioma of malherbe).

A brief review of the literature of pilomatrixoma and report of a case that involved the oral cavity have been presented. Pilomatrixoma is an uncommon benign tumor found primarily in the region of the head and neck and is treated by excision.


Parotid fistula after the use of external pin fixation: report of case.

A case of parotid gland fistula after the use of external pin fixation has been described. Therapy for this condition has been discussed, with the suggestion of minimal treatment for this temporary condition.


Prolonged unilateral dislocation of the mandible.

A 61-year-old white woman dislocated her left condyle. She did not seek care for almost three years. In such a long-standing unilateral dislocation, Gottlieb reported that such extreme adhesions and accumulation of connective tissue develops in the joint cavity that actual reduction is impossible and that violent manipulation may lead to ankylosis. Therefore, in such cases, surgery (condylectomy) is indicated. This was done in our case with good functional results.


Disseminated South American blastomycosis (paracoccidioidomycosis): report of case.

The 11th case of South American blastomycosis occurring in the United States has been reported. Therapy with amphotericin B and sulfisoxazole has been discussed.


Chondroectodermal dysplasia (Ellis-van Creveld syndrome): report of two cases.

Our two patients with chondroectodermal dysplasia had most of the classic manifestations of the syndrome. The simultaneous occurrence of partial anodontia and embedded supernumerary and second premolars in the mandible in one patient was interesting. The inverted impaction of the left maxillary lateral incisor is also a unique finding. The median fissure on the tongue may be an associated developmental anomaly of the syndrome.


Treatment of mandibular cherubism.

A case of cherubism of the mandible with an atypical history and with the onset of the facial deformity delayed until after puberty has been reported. The patient was treated during a relatively inactive stage, which followed a year of rather active growth. The distinct facial deformities were treated by a combination of curettage and recontouring, which resulted in an improved facial appearance and elimination of the fibro-osseous lesions of the mandible.


Analysis of relapse after mandibular advancement surgery.

Seventeen cases of mandibular advancement surgery were evaluated for skeletal relapse; 12 included long-term evaluation. Inferior movement of the proximal segment with displacement of the condyle occurred at the time of surgery or in the immediate postoperative period. This movement was closely associated with subsequent skeletal relapse of the distal segment. This may represent a cause-and-effect relationship mediated through the soft tissue attachments of periosteum and muscle that are stretched at the time of surgery.


Percutaneous total reduction genioplasty.

Macrogenia is a common cause of facial imbalance. Several procedures have been developed to deal with aspects of this problem. They have been associated with occasional failure to attain a reasonably satisfactory result. A unique approach to solve some of the problems of previously described procedures has been developed.


Actinomycotic osteomyelitis of the mandible: report of case.

A case of osteomyelitis of the mandible caused by actinomyces infection is described. Gram stain and cultures of the discharge in fluid thioglycolate medium and blood agar, as well as an analysis of the biochemical properties of the causative organism with API system, indicated the infection was caused by A israelii. Lesions in both hard and soft tissues responded to chemotherapy with cephalexin, minocycline, and aminobenzylpenicillin and drainage of the pus from the cutaneous abscesses.


Repeated human tooth allograft after a previous rejection.

A case has been presented in which a humantooth allograft was performed. It failed in a reasonably expected manner. Another tooth allograft from the same donor to the same host was then performed. It is currently functioning two years postoperatively. This seems to defy the law of second-set reaction. Various explanations for the response to this repeated tooth allograft have been discussed. It is concluded that possibility of repeating tooth allografts, even after a first allograft has failed, should be considered.


Acute frontal sinusitis as a late complication after midfacial trauma.

The anatomical relationships of the frontal and nasoethmoid region are reviewed, with particular emphasis on the nasofrontal drainage system. A case report is presented in which obstruction of the nasofrontal duct created a delayed frontal sinusitis in a patient with severe midfacial trauma. A brief review of the different conditions that can appear as periorbital inflammation in the posttraumatic period is given, followed by a brief discussion of the various therapeutic alternatives available to the surgeon when presented with this situation.


A long-term survey of tooth loss in 600 treated periodontal patients.

1. Six hundred patients in a private periodontal practice were reexamined an average of 22 years after their active treatment and the patterns of tooth loss were observed. 2. During the post-treatment period, 300 patients had lost no teeth from periodontal disease, 199 had lost one to three teeth, 76 had lost 4 to 9 teeth and 25 had lost 10 to 23 teeth. 3. Of 2,139 teeth that originally had been considered of questionable prognosis, 666 were lost. Of these, 394 were lost by one sixth of the patients and only 272 by the other five-sixths. 4. Of 1,464 teeth which originally had furcation involvements, 460 were lost, 240 of them by one-sixth of the patients who deteriorated most. 5. The mortality of teeth which were treated with periodontal surgery was compared with that of teeth which did not have surgery. Tooth retention seemed more closely related to the case type than the surgery performed. 6. In general, periodontal disease is bilaterally symmetrical and there is a predictable order of likelihood of tooth loss according to position in the arch.


A long term study of root retention in the treatment of maxillary molars with furcation involvement.

A study was done to evaluate long-term results of treating 387 maxillary molars with furcation involvement in 100 patients with chronic destructive periodontal disease. Results showed a favorable long term functional survival rate of 341 teeth (88%) 5 to 24 years after treatment, despite the fact that many teeth had at least one root with 50% or less of bone support before treatment. Of the 46 teeth (12%) that were ultimately extracted, 25 were present for a significant length of time (6 to 18 years) before extraction. The radiographs of 292 teeth (75%) showed no significant change in bone support 5 to 24 years after treatement, while those of 8 teeth (2%) suggested improvement. There was perceptible increase in bone loss in 41 teeth (11%). Forty-six (12 %) were extracted. All periodontally involved teeth in each patient of the study were treated. Specific treatment for maxillary molars with furaction involvement included soft tissue therapy; coronal reshaping, if indicated; and instruction in home care. Considerable emphasis was placed on improving occlusal function. In no case was root amputation, hemisection, osseous surgery, or reshaping of the cervical area of the tooth done. A total of 366 (94%) of the teeth did not have endodontic therapy before, during, or after the study. Therefore endodontic therapy was not a significant factor in retention of the 341 teeth.


The free connective tissue autograft: a clinical and histologic wound healing study in humans.

In this report a new method for the management of the soft tissue autograft, based on the concept that some form of control lies in the connective tissue of the periodontium which determines the type and character of the overlying epithelial tissues is presented, along with an insight into the wound healing process.


Effect of an antiseptic mouthwash on plaque accumulation.

This study was undertaken to determine the effect of sodium peroxyborate monohydrate bitartarate on plaque accumulation in comparison with "no oral hygiene" and "brushing once before breakfast." Fifteen male resident students between the ages of 18 to 22 years volunteered for the study. 1. In all three stages of the study regeneration of plaque were observed in all individuals within 24 hours after thorough prophylaxis. 2. The tendency to plaque accumulation varied from person to person, from tooth to tooth in the same individual, and even on different surfaces of the same tooth. 3. The plaque scores and the range of plaque scores were lower on the first 2 days with the use of mouthwash when compared with tooth brushing on the corresponding days. 4. A reduction of 30.62% was observed with the use of mouthwash when it was compared with "no oral hygiene." 5. Plaque accumulation was 17.7% more with mouthwash than with use of the toothbrush. 6. A negligible reduction in efficacy (0.38%) was observed with this mouthwash in comparison with 1% H2O2, used under pressure.


The effect of fluoride and strontium application on dentin: in vivo and in vitro studies.

The effectiveness of topical 2% sodium fluoride applied with and without 10% strontium chloride pretreatment was compared in patients complaining of tooth hypersensitivity. In addition the radiopacity of 2% sodium fluoride and 25% strontium chloride treated dentin was studied in vitro. Reduction of sensitivity to cold and mechanical stimuli was evaluated during a period of 3 months by pain scoring in the exposed cervical dentin of homologous teeth on the two sides of the jaws. There was a significant decrease in the sensitivity of the exposed cervical dentin after treatment with sodium fluoride solution with or without pretreatment with strontium chloride solution. At the end of the experimental period the combined strontium and fluoride treatment was found to be more effective than that of fluoride alone in reducing sensitivity to cold. The increase in radiodensity of dentin samples immersed in strontium chloride was statistically significant, while there was no significant increase in density for the samples immersed in sodium fluoride solutions. A mineralization process is possibly the effective means by which fluoride or strontium diminishes sensitivity of dentin.


Photoelastic comparison of posterior denture occlusions.

The development of stress patterns was observed within a photoelastic model under complete mandidular dentures. Characteristic stress patterns were related to type of tooth material. Plastic teeth transmitted less force than porcelain teeth. Cusp teeth induced concentrated regions of force within the model that contrasted with the uniform distribution of force observed with flat teeth. The dentist should be aware of the biomechanical problems associated with any posterior denture occlusion in relation to the residual alveolar ridge.


Vital root retention in humans: a preliminary report.

With increasing experience in the technique, it has become apparent that more generous contouring of the retained root after amputation is desirable. The effect is to produce a more rounded ridge instead of the "boxy" one that would result from mere horizontal sectioning of the crown structure. The surgical sectioning of vital teeth, followed by anequate mucoperiosteal eversion suturing, has proved to be successful. Periodontal evaluation of each tooth seems to be paramount to success or failure. Accurate impression-making and postsurgical treatment including soft acrylic resin relines and removal of pressure spots appear to be next in importance. Age of the patient, condition of the clinical crowns, and length of surgical procedures did not seem to affect normal healing in the patients involved in the project.


Clinical importance of voluntary and induced Bennett movement.

A total of 136 dentulous patients were divided into three groups for purposes of quantitative pantographic comparison of voluntary and induced Bennett movement. The effects of patient age and operator experience on recording the Bennett movement were also studied. The results indicates that for patients studied with Bennett movement iduced in the manner described: 1. Experienced operators can obtain more induced Bennett movement that inexperienced operators. 2. Inducing Bennett movement has a greater effect on the immediate side shift component than it has on the progressive side shift component. 3. For older individuals the amount and direction of induced immediate side shift is greater than for younger patients, statistically highly significant, and therefore clinically important. In conclusion, if the objective of a pantographic survey is to record the complete capacity of the joint to move, *lateral jaw movements must be induced.


Universal simplified mold technique for construction of facial prostheses.

This article presents a simple procedure for the construction of facial prosthesis. The use of a split mold lined by silicone 382 is recommended. Pertinent information concerning impression making, sculpturing, coloring, and processing to insure esthetically and functionally accepted prostheses is presented.


Conditioning prostheses viewed from the standpoint of speech adaptation.

Subjects who had adapted to experimental alveolar-palatal prostheses for 2 weeks were able to speak naturally with them after a lapse of a month. Physiologic data on jaw motions and tongue-palate contacts during speech showed a rapid return to compensatory articulatory patterns. A single subject who had previously adapted to an experimental prosthesis over a period of a week made the same type of compensatory jaw adjustments when speaking with the prosthesis again 1 year later.


Selective tomography of the TMJ and the myofacial pain-dysfunction syndrome.

Tomography is the only technique that gives a precise representation of the temporomandibular articulation. To delineate a discrete impingement upon the articular space and compare before-and-after treatment modalities it is essential to strictly respect the angular criteria. Selective tomography can be accomplished only if three criteria are met: 1. To make an axial cephalogram perpendicular to the submental-vertical film and to measure the angle of the grand axis of each condyle with the median sagittal plane; 2. To orient the incident ray perpendicular to this axis for the sagittal sections and parallel for the frontal sections; 3. To be sure of the exact position of the head on the tomograph. The teeth also must be placed in maximum occlusal contact.


The frequency of parafunctional occlusal habits compared with the incidence of mandibular displacement.

Acomparison was made in this study of the prevalence of mandibular displacement in varying degrees of complexity with the incidence of parafunctional occlusal habits and some sequelae. The prevalence of occlusal habits in all patients was high but became greater with the increased complexity of the mandibular displacement, especially an asymmetrical slide from RCP to IP. The mulifactorial etiology of parafunctional occlusal habits and their sequelae tends to make the relationships more complex than a simple "cause and effect" and therefore must be considered.


A case-control study of Hodgkin's disease in Israel.

Jewish residents of Israel in 1960-72 with Hodgkin's disease (HD) were compared with controls drawn from the general population. The controls were individually matched by sex, age, origin, and date of immigration. The comparison showed a significant association between HD and parental consanguinity and pointed to the possible etiologic role of recessive inheritance. Females with HD tended to have a lower parity than did their controls. Associations between HD and a high educational level and the presence of a flush toilet in the childhood home were significant and gave limited support to the hypothesis that a high standard of living in childhood increases the risk of subsequent HD. Tonsillectomy and a history of work with wood or trees were significantly associated with mixed cellularity but not with other histologic subtypes. Differences between patients with HD and controls with respect to cigarette smoking, exposure to animals, marital status, previous blood transfusions or jaundice, contact with asbestos, residual or occupational mobility, or other characteristics were not significant.


Transient carcinoembryonic antigen (CEA) elevations following resection of colorectal cancer: a limitation in the use of serial CEA levels as an indicator for second-look surgery.

In a previous study, other investigators recommended second-look surgery for colorectal cancer primarily on the basis of plasma carcinoembryonic antigen (CEA) rises and prepared a nomogram for ready recognition of these "significant" increases. We found 25 patients whose CEA levels met the recommended criteria for significance; however, in 9 of these patients the rises were transient. Eight had no clinical evidence of recurrent cancer and they might have had negative second-look surgery had this been done because of CEA rises alone. The use of the CEA nomogram merely eliminated laboratory variation as a cause of the CEA rise. It did not, however, rule out biologic causes of CEA rises, other than that of cancer, especially benign liver disease. We were unable to differentiate benign from malignant rises on the basis of CEA changes alone. Preoperative CEA values helped to separate the two rises. Transient rises usually began earlier. Malignant CEA rises were more likely to be exponential. The rate of rise alone did not discriminate between the two rises. Thus, although serial CEA levels were helpful in making the decision for reexploration, they did not substitute for complete clinical assessment.


Case-control study of antihypertensive and diuretic use by women with malignant and benign breast lesions detected in a mammography screening program.

A significant but low-level association (relative odds, 2.0; P less than 0.05) was observed between the occurrence of breast cancer and the use of rauwolfia derivatives for 5 or more years in the study of 481 breast cancer cases and 1,268 controls from a joint national mammography screening project of the National Cancer Institute and the American Cancer Society. This association was confined to women over age 50 years who were also heavier than average. No confounding effects could be held responsible for this association after adjustment was made for variables such as presence of hypertension, weight, age at first pregnancy, and other breast cancer risk factors. Other antihypertensive and diuretic drugs as well as multiple drug use also exhibited some suggestive associations with breast cancer. Another group of 421 women with benign lesions at breast biopsy were also compared to the 1,268 controls. They showed a significant association between benign lesions and use of thiazides for 5 or more years (relative odds, 2.4; P less than 0.001) whether employed to treat edema or hypertension. Other antihypertensive and diuretic agents also seemed to show this association, but most of them were being used together with thiazides.


Subsequent cancer in patients with chronic lymphocytic leukemia--a possible immunologic mechanism.

Among 4,869 patients with chronic lymphocytic leukemia (CLL) from the series of the End Results Program of the National Cancer Institute, Bethesda, Maryland, second primary cancers developed in 234 patients, compared to 204.9 expected. The risk was significantly elevated for malignant melanoma, soft-tissue sarcomas, and lung cancer. The frequency of rectal cancer was also elevated, but not significantly. The excess risk for these specific sites persisted throughout the period of follow-up, suggesting a susceptibility state that complicated the leukemic process rather than suggesting methodologic, diagnostic, or therapeutic effects. Immunologic defects to CLL may be involved in the etiology of excess risk for these sites, because a similar array of nonlymphoid tumors was seen following therapeutic immunosuppression among renal transplant recipients.


Unusual configurations of endoplasmic reticulum in cells of acute promyelocytic leukemia.

An ultrastructural study of leukemia cells from 8 patients with acute promyelocytic leukemia revealed several features that have not previously been emphasized: prominent dilated rough endoplasmic reticulum and two unusual configurations of endoplasmic reticulum (ER). The two membrane structures, multilaminar ER and complex stellate arrangements of ER, appeared to be morphogenetically related. The multilaminar ER was observed in every mitotic cell and less frequently in interphase cells. The stellate ER complex was observed only in interphase cells. Ultrastructural evidence is presented to support the possible evolution of the stellate ER complex from the multilaminar ER.


Influence of chemotherapeutic agents on chorionic gonadotropin-alpha subunit secretion in a human lung cancer cell line (ChaGo): discordance of cytotoxic and secretory effects.

Cells from cultures of ChaGo, a cell line of a human lung cancer that ectopically produces chorionic gonadotropin (hCG) and its alpha subunit (hCG-alpha) were exposed to five different cancer chemotherapeutic agents in vitro in separate experiments (one drug/expt). The control doubling time averaged 4 days, with molar biphasic secretory rates of hCG-alpha ranging from a high of 58.1 to a low of 10.5 pmoles/10(6) cells/24 hours. Drug concentrations were chosen to induce a 30-60% inhibition of cell replication over a period of 8-10 days. Neither methotrexate nor vincristine demonstrated major effects on extracellular hCG-alpha production, but each agent moderately depressed cell number and each produced major inhibition of intracellular protein synthesis. Procarbazine inhibited marker production only in slight excess of inhibition of cell growth and cell protein. Actinomycin D and mechlorethamine, however, had profound effects on inhibition of hCG-alpha production in excess of cell growth. Our results indicated that cancer chemotherapeutic agents have specific and differing effects on cell growth and cell protein on the one hand and marker production on the other. These data suggested a mechanism for certain cases of discordance between hormone production and clinical status.


Foreign-body tumorigenesis in mice: DNA synthesis in surface-attached cells during preneoplasia.

(CBA/H X CBA/H-T6)F1 mice were given sc implants of unplasticized vinyl chloride acetate 15 X 22-mm copolymer films. The animals were pulsed with [3H]thymidine at various times during the 15 months following implantation. DNA synthesis occurred in the film-attached cell population, predominantly macrophages, throughout the preneoplastic phase in both females and males. Giant cells with fewer than 10 nuclei were labeled synchronously and asynchronously. No DNA synthesis was detected in giant cells with more than 10 nuclei. Previous studies have shown that phagocytic inactivity and ultrastructural signs of functional dormancy are characteristic for the foreign-body-reactive macrophage. However, this investigation demonstrated that the macrophage was not dormant with respect to DNA synthesis.


Growth and rejection of leukemia cells in individual mice after combined treatment with amphotericin B and 1,3-bis(2-chloroethyl)-1-nitrosourea.

We assayed the femoral marrows of individual AKR mice for leukemia colony-units (LCFU) after treatment with amphotericin B (AmB) and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) or with BCNU alone. No differences between the groups were noted in the first 7 days after treatment. All the mice treated with BCNU alone were dead by day 8, and all the survivors among the animals receiving AmB and BCNU retained high levels of LCFU for 2 more days; these LCFU were subsequently rejected by the host. By day 12, LCFU were undetectable. Histologic examination of organs from the same mice on day 5 showed fewer leukemia cells in the mice treated with the combination of agents. In all treatment groups, mice dying of leukemia early (by day 9) had systemic leukemia and most had central nervous system (CNS) involvement. All animals dying between days 10 and 14 had CNS leukemia, but few had systemic leukemia; at later times, though few animals died, they invariably had CNS leukemia without systemic involvement.


Regression of established tumors in rats by injection of diethylaminoethyl-dextran and Friend murine leukemia virus.

Subcutaneously established tumors in WKA rats were treated with polycation DEAE-dextran (DEAE-D) and Friend murine leukemia virus (F-MuLV). This idea was based on "xenogenization of tumors," which is defined as the immunologic regression of transplanted tumors in syngeneic rats after artificial infection of tumors with murine leukemia viruses. Regressions of subcutaneously established tumors were induced in 13 of 40 (33%) rats by injection of DEAE-D and F-MuLV. Intratumor injections of DEAE-D and F-MuLV increased the regression of tumors in 7 of 12 (58%) rats as compared to that of tumors in 6 of 28 (21%) rats treated with DEAE-D and F-MuLV by other injection routes. Electron-microscopic and immunofluorescence examinations revealed that tumor cells were infected with F-MuLV and acquired F-MuLV-related surface antigen on the cell surfaces. Therefore, the regression in rats of subcutaneously established tumors by the injection of DEAE-D and F-MuLV may have been due to an immunologic mechanism that may have been the same as the xenogenization of transplanted tumors previously infected with murine leukemia viruses.


Effects of levamisole on normal and malignant murine lymphocytes.

Levamisole enhanced transformation of murine lymphocytes stimulated either by mitogens or allogeneic lymphocytes. In a similar dose-dependent pattern it stimulated in vitro growth of L1210, P1798, and 6C3HED but not YAC lymphoma cells. Stimulation of growth of lymphoma cells was greater by peritoneal cells harvested from normal mice 4 days after levamisole injection than by peritoneal cells from untreated mice. This effect correlated with the shortened survival time of BALB/c mice treated with levamisole prior to P1798 implantation compared to that of a control group not pretreated. Administration of levamisole with iodoacetamide-modified tumor cells in immunoprophylaxis studies had no effect on the rejection of a tumor implant or on development of tumor-specific antibody. Levamisole was added to regimens involving asparaginase therapy of 6C3HED-bearing C3H mice and chemoimmunotherapy of BALB/c mice bearing P1798 with methotrexate and iodoacetamide-modified P1798 cells. In neither case were there increased numbers of survivors, and mean survival time was generally decreased for the levamisole-treated groups. The stimulated tumor growth may have been mediated by a direct effect of levamisole on the lymphoma cells, through an effect on other cell types, or by both effects; these effects apparently outweighed potentially beneficial effects of levamisole on the immune system.


Lack of involvement of 6-hydroxymethylation in benzo[a]pyrene skin tumor initiation in mice.

The skin tumor-initiating activities of benzo[a]pyrene (BP), 6-hydroxymethylbenzo[a]pyrene (6-OH-CH2-BP), and 6-methylbenzo[a]pyrene (6-CH3-BP), as well as the effects of 7,8-benzoflavone (7,8-BF), quercetin, and 1-benzylimidazole on their activity, were determined in outbred female CD-1 mice by use of a two stage system of tumorigenesis. The skin tumor-initiating activity of 6-OH-CH2-BP and 6-CH3-BP was 12.5 and 20%, respectively, of the activity of BP, 7,8-BF had little effect on the skin tumor-initiating activity of 6-OH-CH2-BP and 6-CH3-BP. However, a dose-dependent inhibition of BP tumorigenesis by 7,8-BF was noted. Quercetin and 1-benzylimidazole also inhibited BP skin tumor-initiating activity. These findings indicated that direct hydroxymethylation of BP is not an important pathway in the activation of BP in mouse skin tumor initiation.


Resistance of G mice to murine leukemia virus infection: apparent disparity in in vivo and in vitro resistances.

We observed a marked discordance between in vivo and in vitro sensitivities to Friend murine leukemia virus in G mice. In vivo resistance of G mice was more than 10(5)-fold relative to sensitive DDD mice, whereas in vitro resistance was only 50 to 100-fold. In vivo sensitivity to N- and NB-tropic Friend murine leukemia virus was recessive in (G X DDD)F1 mice, whereas in vitro sensitivity was dominant in the heterozygotes. The resistance of mouse fibroblasts was different from the resistance of fibroblasts of a certain NZB mouse strain.


Rat ileocecal immunocytoma. An ultrastructural study with special attention to the presence of viral particles.

Fifteen spontaneous immunocytomas originating in the ileocecal lymph nodes of Lou/C/Wsl rats were studied by means of electron microscopy. The histology was characteristic, the tumor being formed by an accumulation of large, rounded cells with slightly eccentric ovoid nuclei, large nucleoli, and finely condensed chromatin along the nuclear walls; the cytoplasma was rich in polyribosomes. The appearance of the rough endoplasmic reticulum was apparently the same whether or not the tumor was secretory. Its development varied from one cell to another, and in only a small proportion of cells did it attain any considerable volume. In all the tumors examined, we noted the presence of intracisternal A-particles. In its morphology, the rat immunocytoma resembled the plasmacytomas induced in mice, and it also resembled certain human tumors such as Burkitt's lymphoma.


Induction of colon tumors in 1,2-dimethylhydrazine-resistant Lobund Wistar rats by methylazoxymethanol acetate.

Sprague-Dawley and Lobund Wistar rats, which were sensitive and resistant to induction of colon tumors by 1,2-dimethylhydrazine (DMH), respectively, were treated with methylazoxymethanol (MAM), the product of DMH metabolism by the microsomal mixed-function oxidase system. Although the colon tissue in both stocks of rats had similar NAD+-dependent dehydrogenase activities that are considered necessary to activate MAM to an ultimate carcinogen, still a sevenfold greater incidence of colon tumors was found in the Sprague-Dawley rats, and their tumors were more extensive. The results indicated that the difference in susceptibility to colon tumor induction between the rat stocks was partially related to metabolic activation of the DMH and to other, as yet undetermined, endogenous factors.


Effect of dietary fat saturation on survival of mice with L1210 leukemia.

We examined L1210 murine leukemia growth rate and survival of host male DBA/2J mice fed a diet rich in either polyunsaturated fat (16% sunflower oil) or saturated fat (16% coconut oil). The survival of mice that received transplants of L1210 leukemia cells was longer among the animals that had ingested a diet rich in the saturated fat as compared to those fed the more unsaturated fat. In duplicate experiments, the mean survivals of mice fed coconut oil were 200.9 +/- 1.6 and 202.5 +/- 3.4 hours compared to 188.7 +/- 5.3 and 187.6 +/- 3.5 hours for those fed sunflower oil. Tumor growth rate or the rate of DNA synthesis by the leukemia cells did not differ between the two experimental groups. Therefore, the alteration in survival was apparently due to an effect of the diets on the responses of the hosts rather than their effect on tumor size or growth rate.


Kinetic studies on the hepatic microsomal metabolism of dimethylnitrosamine, diethylnitrosamine, and methylethylnitrosamine in the rat.

The oxidative dealkylation of dimethylnitrosamine (DMN), diethylnitrosamine (DEN), and methylethylnitrosamine (MEN) by Sprague-Dawley rat liver microsomes was studied by a colorimetric assay for the simultaneous analysis of formaldehyde and acetaldehyde. Dealkylation in each instance followed Michaelis-Menten kinetics, but the Michaelis constant (Km) for DEN was an order of magnitude smaller than the Km for DMN. Km values for demethylation and deethylation of MEN were intermediate between those for DMN and DEN. DMN inhibited-deethylase, and DEN inhibited DMN-demethylase activity. The inhibition was of a mixed type in both instances.


[Peripheral microthrombotic purpura associated with acute promyelocytic leukemia in pregnancy. A light and electron microscopic study].

A case is presented of a pregnant patient in the 28th week of gestation with promyelocytic leukemia and an unusual thrombohemorrhagic skin lesion. Ultrastructural examination revealed a microthrombotic purpura. Reduced coagulation factors increased during heparin treatment. The exacerbation of disseminated intravascular coagulation is explained by a hypercoagulable state in pregnancy in association with the as yet unknown etiology of "promyelocytic fibrinopathic leukemia".


Maturation and proliferation capacity of blood cells from untreated acute myeloid leukemia and its prognostic significance.

Blood cells from 68 patients with untreated acute myeloid luekemia were cultured in RPMI-medium without stimulating factors up to ten days. The cultures showed in part maturation and proliferation to monocytes-macrophages, in part to promyelocytes, myelocytes and Pelger-like cells, in part we did not find any differentiation or the cultures were degenerated during the first days. Retrospectively we found that in the 16 blood cell cultures with capacity to differentiation into the monocyte-macrophages-system 5 patients had a smouldering leukemia. Our preliminary evidences suggest that the diagnosis "smouldering leukemia" is to be found with out in vitro culture system. Further analysis suggest that patients with acute leukemia whose blood cells have the capacity for maturation to monocytes-macrophages or to promyelocytes, myelocytes and Pelger-like cells have a better chance of achieving a complete remission and a longer median survival time.


Hypertrophic osteoarthropathy in association with pulmonary metastasis from osteogenic sacroma.

Hypertrophic osteoarthropathy in children is rare, especially when it is associated with lung metastsis. The patient reported herein had metastic osteogenic sarcoma and failed to respond to chemotherapy or thoractomy. There are several theories as to the pathogenesis of osteoarthropathy, but none is totally convincing. Vagotomy or transection of intercostal nerves has been advocated to relieve the symptoms of osteoarthropathy.


Vincristine (NSC-67574), cytosine arabinoside (NSC-63878), 6 thioguanine (NSC-752) and daunorubicin (NSC-82151) (VAT-D): a pilot study of combination chemotherapy for remission induction in acute myeloid leukemia in adults.

Fifteen newly diagnosed unselected adult patients with acute nonlymphocytic leukemia were treated in a pilot study of the combination of vincristine, cytosine arabinoside, 6-thioguanine, and daunorubicin (VAT-D) for remission induction therapy. Eleven of fifteen (75%) achieved a remission bone marrow. Median duration of remission was seven months in all responders (11 patients). The 11 patients achieving initial remission reached a median survival of 14 months. Twelve of seventeen attempts at reinduction of remission with VAT-D were successful. The total amount of daunorubicin required for induction was less than that required in the majority of reported acute leukemia treatment regimens utilizing daunorubicin.