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M Bogart

Publications and source records attributed to M Bogart.

9 recordsLinked to original sources
PubMed1999

Growth of rat mesangial cells on oxidized extracellular matrix increases inducible nitric oxide synthase activity.

Biochemical modification of extracellular matrix (ECM) proteins can alter the function in overlying cells. We tested the hypothesis that metal-catalyzed oxidation of native ECM and individual matrix proteins modulates the activity of inducible nitric oxide synthase (iNOS) in cultured rat mesangial cells (RMC). Oxidized modification of native ECM resulted in a 32% increase in iNOS activity (P<0.01) without influencing the response to supplemental L-arginine or to the addition of the iNOS inhibitor, L-NAME. Immunoblot analysis indicated that enhanced iNOS activity was not associated with a parallel rise in the cytosolic content of iNOS. Synthesis of type IV collagen was unaffected by growth of RMC on oxidized native ECM. Oxidation of three normal constituents of the mesangial matrix - type IV collagen, laminin, and fibronectin - also stimulated iNOS activity in overlying RMC by 18-32% (P<0.05). Growth of RMC on oxidized type I collagen or Vitrogel had no effect on NO production. We conclude that oxidized modification of the mesangial matrix promotes increased iNOS activity and NO production by mesangial cells. Further work is required to determine whether this response limits glomerular injury or promotes damage to the mesangium in oxygen free radical-mediated diseases such as chronic renal failure, atherosclerosis and diabetes.

Animals↗
PubMed1998

High glucose enhances growth factor-stimulated nitric oxide production by cultured rat mesangial cells.

Nitric oxide (NO) contributes to the alterations in glomerular hemodynamics and extracellular matrix accumulation observed in diabetic nephropathy. High glucose concentrations directly inhibit NO production by rat mesangial cells (RMC). However, the role of peptide growth factors and chemokines in regulating NO synthesis by RMC under normal and high glucose conditions has not been studied. Therefore, we examined the effect of IGF-I, EGF, TGF-beta and RANTES on NO production by RMC maintained in normal (5.6 mM) or high glucose (33.3 mM) for 48 h. No synthesis was determined by measuring nitrite accumulation in conditioned media with the Greiss reaction. In normal glucose media, IGF-I, EGF, and RANTES had no effect on nitrite accumulation while TGF-beta inhibited NO synthesis. In high glucose conditions, IGF-I and EGF significantly enhanced NO production. The effects of RANTES and TGF-beta were unchanged by an elevated glucose concentration. EGF-induced stimulation of NO production in high glucose media was associated with parallel alterations in iNOS gene and protein expression. The modest enhancement in nitrite accumulation provoked by IGF-I in high glucose conditions was not accompanied by demonstrable increases in iNOS mRNA abundance or protein content. In conclusion, peptide growth factors modulate the direct inhibitory effect of high glucose on NO production by cultured mesangial cells. These actions in vivo may limit the adverse consequences of reduced NO production in promoting diabetic nephropathy.

Animals↗
PubMed1993

P53 mutation in acute T cell lymphoblastic leukemia is of somatic origin and is stable during establishment of T cell acute lymphoblastic leukemia cell lines.

Samples donated by patients with T cell acute lymphoblastic leukemia (T-ALL) were screened for mutations of the p53 tumor suppressor gene. Peripheral blood cells of T-ALL relapse patient H.A. were found to possess a heterozygous point mutation at codon 175 of the p53 gene. To determine whether this was an inherited mutation, a B cell line (HABL) was established. Leukemic T cell lines (HATL) were concurrently established by growing peripheral blood leukemic T cells at low oxygen tension in medium supplemented with IGF-I. Previously we had shown that > 60% of leukemic T cell lines possessed mutations in the p53 gene (Cheng, J., and M. Hass. 1990. Mol. Cell. Biol. 10:5502), mutations that might have originated with the donor's leukemic cells, or might have been induced during establishment of the cell lines. To answer whether establishment of the HATL lines was associated with the induction of p53 mutations, cDNAs of the HATL and HABL lines were sequenced. The HATL lines retained the same heterozygous p53 mutation that was present in the patient's leukemic cells. The HABL line lacked p53 mutations. Immunoprecipitation with specific anti-p53 antibodies showed that HATL cells produced p53 proteins of mutant and wild type immunophenotype, while the HABL line synthesized only wild-type p53 protein. The HATL cells had an abnormal karyotype, while the HABL cells possessed a normal diploid karyotype. These experiments suggest that (a) p53 mutation occurred in the leukemic cells of relapse T-ALL patient HA; (b) the mutation was of somatic rather than hereditary origin; (c) the mutation was leukemia associated; and (d) establishment of human leukemia cell lines needs not be associated with in vitro induction of p53 mutations. It may be significant that patient HA belonged to a category of relapse T-ALL patients in whom a second remission could not be induced.

Adult↗
PubMed1991

Interstitial deletion of chromosome 2q associated with ovarian dysgenesis.

In the present report we describe a girl with mental retardation, Dandy-Walker malformation, craniofacial anomalies, cardiac defect, and ovarian dysgenesis associated with an interstitial deletion of chromosome 2. The interstitial deletion in the proband was associated with an apparently balanced translocation involving chromosomes 2 and 7 in the father.

Abnormalities, Multiple↗
PubMed1990

Two live-born infants with trisomy 22.

The autopsy findings and karyotypes of two live-born fetuses with full trisomy 22 are discussed. Confined placental mosaicism was documented in one of the two cases. Confined placental mosaicism may play a role in the intrauterine survival of some trisomy 22 conceptions.

Abnormalities, Multiple↗
PubMed1987

Prevalence of antibodies to the human immunodeficiency virus in Dominicans and Haitians in the Dominican Republic.

Few patients with the acquired immunodeficiency syndrome have been reported in the Dominican Republic, although they share the island of Hispaniola with Haiti, which has numerous cases. Prevalence of antibodies to the human immunodeficiency virus in serum samples from Dominicans tested from 1983 through 1985 was low in comparison with that of clinically healthy Haitians working in the country. The Haitians, who gave no history of any known risk factor, had a seroprevalence to the virus of more than 10%. Only Dominican homosexuals had a high rate of seropositivity (19%); intravenous drug abusers, healthy heterosexuals, female prostitutes, and other subgroups had virtually no evidence of antibodies to the human immunodeficiency virus. These results suggest that passage of the acquired immunodeficiency syndrome retrovirus between populations in two countries on the same island did not occur except by known risk practices. They emphasize that the extent of viral transmission in Haiti is greater than that observed in the Dominican Republic.

Acquired Immunodeficiency Syndrome↗
PubMed1970

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Education, Nursing, Continuing↗