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Biomedical subjects

G Feldman

Publications and source records attributed to G Feldman.

At least 19 recordsLinked to original sources
PubMed1992

Endodontic stabilizers.

With the recent influx of osseointegrated endosseous implants in dentistry, attention has been drawn away from using endodontic stabilizers as a means of stabilizing and retaining teeth. It is our opinion that endodontic stabilizers should be considered in the treatment planning of seemingly nonretainable teeth. They are biocompatible and have the additional advantage of maintaining the periodontal membrane attachment of the remaining tooth. Extraction and subsequent replacement with osseointegrated implants should only be considered after all other means of retaining the natural tooth have been fully explored. Selective case studies from various areas of the dentition demonstrate the broad applicability of stabilizers. A technique is presented for the use of endodontic stabilizers.

Dental Abutments↗
PubMed1989

Quantitative computerized joint scanning in rheumatoid arthritis: an accurate reproducible method of quantitating synovitis--preliminary report.

Clinical trials in rheumatoid arthritis have been hampered by the highly subjective nature of disease assessment measures and lack of a consistently reliable laboratory test to follow. The authors devised a method of quantitating synovitis by computerized joint scanning and compared it with six conventional parameters in 18 patients entered into two treatment protocols and a control group. The results indicate that quantitative joint scanning probably is at least as reliable as the conventional measures and has the advantage of having no placebo or subjective component.

Adult↗
PubMed1987

[Effects of normobaric oxygen on rat hepatocytes].

Exposure of adult rats to oxygen (100%) during 55 hrs decreases their sleeping time induced by pentobarbital and doesn't modify their paralysis time provoked by zoxazolamine. At 48 and 55 hrs, the hepatic cytochrome P-450 decreases significantly. Morphological study showed tissular changes suggestive of hepatic hemodynamic perturbations, which are probably responsible for the functional modifications.

Animals↗
PubMed1986

Co-ordinate increase in the expression of type I and type III collagen genes in progressive systemic sclerosis fibroblasts.

Progressive systemic sclerosis (PSS), is a connective tissue disease characterized by excessive accumulation of collagen in the skin and various internal organs which is due, at least in part, to increased collagen production by PSS fibroblasts. In order to examine the molecular mechanisms responsible for this abnormality, we compared the kinetics of collagen biosynthesis, the intracellular degradation of collagen and the expression of Types I and III procollagen genes between normal and PSS dermal fibroblasts in culture. Two age- and sex-matched normal and PSS dermal fibroblast cell lines were studied. The results showed that the PSS cultures produced higher amounts of collagen than did normal fibroblasts and displayed an abnormal kinetic pattern. Furthermore, the PSS cells showed a slight but statistically significant increase in the fraction of collagen degraded intracellularly when compared with normal cells (23% against 18% respectively). The levels of mRNA for procollagen Types I and III were determined by Northern and dot-blot hybridization with specific cloned cDNA probes for alpha 1(I), alpha 2(I) and alpha 1(III) and it was found that they were 2-3-fold higher for each of the three chains in the PSS cell lines compared with the controls. These findings indicate, therefore, that the overproduction of collagen characteristic of PSS fibroblasts can be largely accounted for by the increased levels of collagen mRNA.

Cell Line↗
PubMed1986

Inhibition of excessive scleroderma fibroblast collagen production by recombinant gamma-interferon. Association with a coordinate decrease in types I and III procollagen messenger RNA levels.

The effects of recombinant gamma-interferon (rec gamma-IFN) on collagen production by confluent monolayer cultures of progressive systemic sclerosis (PSS) dermal fibroblasts were studied. Five cell lines obtained from patients with rapidly progressive disease of recent onset were examined. All PSS fibroblast cell lines exhibited increased collagen production when compared with normal skin cell lines. It was found that rec gamma-IFN caused potent inhibition of PSS fibroblast collagen production in a concentration-dependent manner. Greater than 50% inhibition was observed with as little as 50 antiviral units/ml, and maximal effects were attained at a concentration of 500 units/ml. The rec gamma-IFN caused reproducible inhibition of collagen production by the 5 PSS fibroblast cell lines, ranging from 58.9% to 85.6% of control values. Measurement of type I and type III procollagen messenger RNA (mRNA) levels with specific complementary DNA probes demonstrated a coordinate reduction of greater than 60% in mRNA for both transcripts in rec gamma-IFN-treated cells, compared with control cells. These findings indicate that rec gamma-IFN can modulate the excessive collagen biosynthesis characteristic of PSS fibroblasts and that this effect can be explained largely by the gamma-IFN-mediated decrease in specific collagen mRNAs.

Adult↗
PubMed1985

Legislating health care coverage for the unemployed.

Because the unemployed and their families are often likely to develop stress-related health problems, ensuring them access to health care is a public health issue. Congressional efforts thus far to legislate health coverage for the unemployed have proposed a system that recognizes people's basic need for coverage but has several limitations.

Delivery of Health Care↗
PubMed1984

Transcriptional control of human diploid fibroblast collagen synthesis by gamma-interferon.

Recombinant gamma-interferon (rec gamma-IFN) caused potent inhibition of collagen synthesis by cultured confluent human diploid fibroblasts in a dose-dependent manner. Gel electrophoresis of the newly synthesized proteins from the culture media of rec gamma-IFN-treated fibroblasts demonstrated a selective depression of procollagen without a significant change in non-collagenous proteins. Dot blot hybridization to a Type I procollagen cDNA probe showed that the inhibition of collagen production was accompanied by a decrease in the levels of collagen mRNA. These results indicate that rec gamma-IFN is capable of exerting transcriptional modulation of collagen biosynthesis and suggest that it may play an important role in regulation of normal and pathologic fibrogenesis.

Cells, Cultured↗
PubMed1984

Cardiovascular and renal effects of isoproterenol infusions in young swine.

The cardiovascular and renal effects of intravenous (i.v.) and intra-arterial (i.a.) infusions of isoproterenol (ISP, 0.1-0.2 micrograms/kg/min) were evaluated in 17 two-week-old swine anesthetized with pentobarbital. The glomerular filtration rate (GFR) of each kidney and blood flow and vascular resistance (RVR) of the left kidney were determined in all animals. In the 8 animals given ISP i.v., right ventricular pressure and dP/dtmax were also determined via a thoracotomy. In 9 animals, ISP was given i.a. after stabilization of constant-flow perfusion of the left kidney in situ. During i.v. infusion of ISP, the positive inotropic and chronotropic effects and the decrease in arterial pressure were maintained; renal blood flow and GFR increased and RVR decreased. During i.a. infusion of ISP in the constant-flow perfused kidney, similar changes in RVR and GFR were observed despite the higher effective concentrations of drug reaching the kidney. We conclude that, at this stage of postnatal renal development, the infusion of cardiotonic doses of ISP lowers RVR and produces a small increase in GFR.

Animals↗
PubMed1983

Serial transmission of hepatitis B like non-A, non-B hepatitis and associated markers to chimpanzees successfully immunized against HBV.

In order to demonstrate that the HBV like strain of NANB hepatitis bred true as non-B together with its associated markers, 2 chimpanzees with high titer anti-HBs (45 and 125 AUSAB RU respectively) immunized with the Pasteur HB vaccine received 1 ml IV of a NANB inoculum. Two neighbour captive animal served as controls. The inoculum was the serum of a leukemic patient in remission for over 3 years with NANB chronic active hepatitis which serum contained HBV like particles and was found positive for NANBe Ag and anti-NANBc whereas in the liver typical numerous "SHIMIZU" dense soft edge aggregated intranuclear structures were demonstrated by electron microscopy. After 4 weeks portal inflammation and hepatocyte necrosis with significant aminotransferase elevation lasting for over 10 weeks developed in the 2 infected chimpanzees. No change in anti-HBs titer was seen and HBs, HBc, HBe Ag and/or AB could neither be detected in serum by RIA nor in liver by immunofluorescence during the 6 month follow up period. By contrast NANBc Ag became clearly demonstrable by immunofluorescence in the liver nuclei together with anti-NANBc in the serum after the 6th week and both persisted for over 4 months. Double unit structures similar to those of NANB/F strain were demonstrable in the cytoplasm at the acute phase. None of these changes was seen in the two control animals. Inoculation of the acute phase serum in the 2 previous control animals was again followed by the same sequence of events. Hybridization studies with HBV DNA of liver biopsies of infected chimps were negative.

Animals↗
PubMed1981

Multiple carboxylase deficiency: clinical and biochemical improvement following neonatal biotin treatment.

Multiple carboxylase deficiency is characterized by deficient activities of three biotin-dependent enzymes, propionyl coenzyme A carboxylase, pyruvate carboxylase, and beta-methylcrotonyl coenzyme A carboxylase. A newborn infant was seen with metabolic ketoacidosis, hyperammonemia, organic aciduria, seizures, and coma. Multiple carboxylase deficiency was subsequently confirmed by enzyme activity determinations in his peripheral blood leukocytes and cultured skin fibroblasts. The infant's neurologic and metabolic status improved markedly within a few days of administration of pharmacologic doses of oral biotin. His EEG, which was distinctly abnormal, became normal; his extensive computed tomography scan changes resolved, with the exception of ventricular dilation, over the next two months. After two weeks of biotin treatment the excretion of abnormal organic acid metabolites was reduced and his carboxylase activities increased to the normal range. However, the activities of these enzymes increased only to 30% to 55% of normal in fibroblasts incubated in supplemental biotin. This partial correction of enzyme activity differs from that observed in other individuals with multiple carboxylase deficiency and suggests biochemical heterogeneity in this disorder. Prompt diagnosis and intervention can avert some of the pathologic complications of this biotin-responsive condition.

Biotin↗