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Biomedical subjects

M Goldberg

Publications and source records attributed to M Goldberg.

At least 361 records · Page 20Linked to original sources
PubMed1990

Identification of a 180 kD protein in Escherichia coli related to a yeast heavy-chain myosin.

A high molecular-weight protein from Escherichia coli sharing structural homology at the protein level with a yeast heavy-chain myosin encoded by the MYO1 gene is described. This 180 kD protein (180-HMP) can be enriched in cell fractions following the procedure normally utilized for the purification of non-muscle myosins. In Western blots this protein cross-reacts with a monoclonal antibody against yeast heavy-chain myosin. Moreover, antibodies raised against the 180 kD protein cross-react with the yeast myosin and with a myosin heavy chain from chicken. Recognition by anti-180-HMP antibodies of an overexpressed fragment of yeast myosin encoded by MYO1 allows the localization of one of the shared epitopes to a specific region around the ATP binding site of the yeast myosin heavy chain. The existence of a high molecular-weight protein with structural similarity to myosin in E. coli raises the possibility that such a protein might generate the force required for movement in processes such as nucleoid segregation and cell division.

Antigens, Bacterial↗
PubMed1990

Regulation of macrophage function by interferon-gamma. Somatic cell genetic approaches in murine macrophage cell lines to mechanisms of growth inhibition, the oxidative burst, and expression of the chronic granulomatous disease gene.

The importance of oxidative cytocidal mechanisms of phagocytic cells in immune protection against microbial pathogens is uniquely revealed by chronic granulomatous disease (CGD), a genetic deficiency disease of man. This cytocidal response in mononuclear phagocytes is principally regulated by IFN-gamma. A somatic cell genetic approach was taken to select oxidative variants from a cloned murine macrophage cell line, J774.16, which formally permitted us to dissociate three regulatory effects of IFN-gamma on these cells: the antiproliferative effect, the antiviral effect, and production of superoxide anion. Half of the variants defective in O-2 production after phorbol myristate acetate stimulation were also resistant to the antiproliferative effects of IFN-gamma. This result suggests that IFN-gamma-induced growth inhibition and production of cytocidal oxygen intermediates are mediated via a common pathway. The somatic cell genetic approach has allowed us to develop in vitro macrophage models for several forms of CGD. One variant characterized in detail, D9, was unable to produce superoxide after stimulation by phorbol esters. At the molecular level, Northern blot analysis revealed that the mRNA encoding the large subunit of the putative CGD gene product, cytochrome b558, was absent in this variant. Another class of variants constitutively unable to produce O-2 or the cytochrome b558 mRNA could be induced to do so by IFN-gamma. These somatic mutants may be useful models in clarifying the role of the CGD gene product and its regulation in the production of cytocidal oxygen intermediates.

Animals↗
PubMed1990

Visualization of glycosaminoglycans in rat incisor predentin and dentin with cetylpyridinium chloride-glutaraldehyde as fixative.

Using cetylpyridinium chloride (CPC) in glutaraldehyde as fixative, we observed sinuous fiber-like structures 300-500 nm long and 7-14 nm thick in the spaces between the collagen fibers of rat incisor predentin. Small granules and fibrils were also detected. Electron-dense vesicles were seen inside the odontoblast processes. The plasma membrane was irregularly stained with material that adhered to its surface. In demineralized dentin, needle-like structures were seen at the periphery of globular structures which were not stained. Staining the sections with Alcian blue did not greatly improve the visualization of CPC-precipitated glycosaminoglycans. The specificity of staining was assessed on serial sections by selective dissociation of glycosaminoglycan aggregates with 2 M calcium chloride and their digestion by bovine testicular hyaluronidase. The glycosaminoglycans were probably combined with lipids, because treatment of the sections with a chloroform/methanol mixture removed the CPC-induced precipitates from both predentin and dentin.

Aldehydes↗
PubMed1990

Effect of gentamicin on the auditory brainstem evoked response in term infants: a preliminary report.

Seven essentially healthy term infants who received gentamicin starting on the 1st day of life for prolonged rupture of membranes and maternal fever were compared with nine healthy term infants to determine whether this drug induces alterations in the auditory pathway. The auditory pathway was studied on the 3rd day of life by analyzing brainstem auditory evoked potentials elicited by a click stimulus presented at the infant's ears. Latencies of components III and V, interval I-III, and interval I-V were significantly prolonged in the gentamicin group, indicating impairment of the central component of the auditory pathway. Peak and trough serum gentamicin levels all fell within the recommended therapeutic range. The study indicates that short course gentamicin therapy in healthy newborn infants can lead to abnormality of auditory function.

Bacterial Infections↗
PubMed1990

Platelet counts in maternal and umbilical venous blood at the time of delivery.

Platelet count in 38 paired maternal venous and umbilical venous specimens were determined at delivery. Umbilical values were significantly higher than simultaneous maternal values (p = 0.004), and a significant relationship was demonstrated between umbilical values and maternal values (r = 0.54, p = 0.0004). Associations between platelet counts and acid-base variables were found to be insignificant in the mother and the umbilical cord.

Adolescent↗
PubMed1990

Risk factors for syphilis: cocaine use and prostitution.

In Philadelphia, a large increase in syphilis among minority group heterosexuals began in 1986 and preceded similar increases elsewhere in the United States. To determine reasons for this increase, we conducted a case-control study in the metropolitan sexually transmitted diseases clinic during 1987 and 1988. Cocaine use (odds ratio [OR] 3.1; 95% confidence interval [95% CI] = 1.5, 6.5 among men; OR 5.8; 95% CI = 1.5, 33 among women) and exchange of drugs for sex (OR 3.5; 95% CI = 1.4, 8.7 among men) were risk factors for syphilis. Although cocaine users reported more sexual partners and more frequently reported sex with prostitutes, cocaine use remained a risk factor after adjustment for these behaviors. These data suggest that sexual behavior or another factor, such as availability or utilization of health care, among cocaine users leads to increased risk of syphilis in this population. Increases in cocaine use may be partly responsible for recent increases in syphilis incidence in the United States.

Adult↗
PubMed1990

[Use of the CO2 laser in enamel-dentin bonding procedures: experimental findings].

The objective of this study is to verify if laser (CO2) preparation of dental tissues has an effect on the quality of the seal of composite fillings. Forty-eight cavities were filled with the Scotchprep/Scotchbond 2 system, using P 50 (3M) as filling material, following the clinical protocol of the system; 40 cavities had previously been treated with a CO2 laser Sharplan 1020 (SBM). The teeth were thermocycled (240 cycles 4 degrees C/55 degrees C), then placed in a 0.5% basic fuschine solution for 48 hours after isolation of the root dentin. After inclusion and section, the penetration of the coloring agent was examined at the interface tooth-filling. This was followed by examination of the interface composite-tooth with the Scan Electronic Microscope. In order to visualize a possible alteration of the dentinal seal, 4 cavities treated with laser were placed in a 0.5% basic fuschine solution for 48 hours after isolation of the root dentin. Four reference cavities were cut with a diamond bur on a high speed handpiece. The following results were obtained: 1) the dentinal permeability of the laser-treated samples increases markedly in comparison with the reference group. 2) the filling-tooth junction of the laser-treated samples were never dye-tight (contrary to the reference samples). 3) fissures were created in the enamel and the dentin. The Scan Electron Microscopy confirms these results.

Carbon Dioxide↗
PubMed1990

A radioautographic comparison of in vivo 3H-proline and 3H-serine incorporation in the pulpal dentine of rat molars: variations according to the different zones.

3H proline and 3H serine were injected intraperitoneally to rats which were killed 4 and 24 hours later. The incorporation of the labelled precursors was studied in the odontoblasts, predentine and dentine of the first lower molars. After radioautography, statistically significant differences in grain density appeared between the furcation, occlusal and lateral areas of the pulp chamber. The incorporation of predentine components into dentine was faster in the lateral than in the occlusal area, the slowest being detected in the furcation area. These differences may be related to the distribution of occlusal forces in the rat molar.

Animals↗
PubMed1990

Annexins I-VI in secretory ameloblasts and odontoblasts of rat incisor.

Immunoblot analyses and ultrastructural immunogold studies have been conducted on annexins in the secretory ameloblasts and odontoblasts of the rat incisor. Annexins I and II were seen in the soluble and particulate fractions of the enamel-related portion but not in the dentin-related portion. These proteins were visualized in the cytosol, near to the plasma membrane of Tomes' processes and in secretory vesicles in the ameloblasts. The forming enamel was also labeled. Annexins III, VI an V were detected in both the soluble and particulate fractions of the enamel-and dentin-related portions. Annexin IV was mainly localized in the proximal and distal areas of the secretory ameloblasts and virtually absent from in the supranuclear area. Annexin V was mainly detected in the cytosol of the cells and to a lesser extent near the plasma membrane. Annexin VI was mainly detected in the particulate fraction of enamel- and dentin-related portions. It was seen in the mitochondria and in the subplasmalemmal undercoat. All these proteins may play a role in exocytosis and endocytosis. They are implied in the regulation of cell calcium, but not in the transfer of calcium through the cells in the direction of the forming enamel and dentin, except annexins I and II since they are both present in the secretory vesicles and in the forming enamel.

Ameloblasts↗
PubMed1990

Calcium and phosphate uptake of human dental enamel treated with sodium bicarbonate.

Enamel cylinders, submitted to the action of NaHCO3 solutions or kept in water, were immersed in a remineralizing solution containing radioactive calcium and phosphate. The calcium uptake was increased in NaHCO3 treated samples, but not the phosphate uptake. Less calcium adsorption was found in 72 h--NaHCO3 treated samples, than after 1 h and 24 h respectively.

Bicarbonates↗
PubMed1990

[Bonding and enamel prisms: is the "bevel" still significant?].

Following a recall of the various preparations of the cavo-surface for posterior composites (straight, rounded, concave bevel, or without bevel), a study at the M.E.B. analysed the interface between the tooth and the filling in each case investigated. With the straight bevel with a slight angulation (40 degrees), the limit of the cavity-filling joint is clear. A disintegration of the material exists with the straight bevel having a 70 degrees angulation. The hiatus is even more marked with rounded or concave bevels. The absence of a bevel provides a clear occlusal joint without irregularity at the cavo-surface limit. In the light of this investigation and the results observed in the clinic in the medium and long term, it appears that the preparation of the cavo-surface margins of occlusal cavities of the pre-molars and molars for posterior composites may make do with a bevel which is not very extensive and not widely opened (40 degrees), or even the total absence of a bevel.

Bicuspid↗
PubMed1990

Megaesophagus and recurrent apnea in an adult patient with familial dysautonomia.

A 42-yr-old woman with familial dysautonomia (FD) presented with severe episodes of apnea during the daytime, as well as during sleep. Investigations revealed a megaesophagus and a lower esophageal constriction. These caused accumulation of food in the esophagus, resulting in recurrent aspiration and apnea which disappeared after gastrostomy. Megaesophagus, a rare complication in FD patients, can occur in other diseases with autonomic dysfunctions, and one must be aware of its potential respiratory complications.

Adult↗
PubMed1990

[Comparison of observed and expected person-years: a simulated approach].

In Epidemiology, no simple test is available for comparing an observed number of exposed person-years with an expected number. The number of person-years is a sum of lengths of stays which is not normally distributed under the null hypothesis. A method is proposed and an example is given. The objective was to study in the French territory of New-Caledonia the relationship between past places of living and occurrence of respiratory cancers. The total observed number of person-years in a zone, among cases, was compared to an expected distribution, based on censuses and controlling for two confounding factors, period of stay and ethnic group. Different methods are compared: a test based on a simulated distribution, and parametric approaches with normality assumption. If the number of cases is small, the simulation test seems to be the best approach.

Analysis of Variance↗