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Biomedical subjects

R M Friedman

Publications and source records attributed to R M Friedman.

At least 109 records · Page 6Linked to original sources
PubMed1986

Eicosanoids, gamma-interferon and inflammatory cells in kidney transplant patients.

Urinary i-TXB2 of renal transplant patients was found to be unaffected by CsA administration. Thus CsA treatment is unlikely to contribute to false positive values in this diagnostic indicator of rejection. It is possible that CsA treatment may suppress the peak i-TXB2 attending rejection but this does not seem to be the case. Studies on rats with cardiac allografts show CsA not to attenuate the rejection i-TXB2 peak (8). The causal role of thromboxane in transplant rejection was further amplified by experimental studies in rats where the cardiac allograft was protected by thromboxane synthase inhibitors and receptor antagonists. The inflammatory cell infiltrate of clinical renal allografts correlated with urine i-TXB2. These data strengthens the diagnostic value of urine i-TXB2 as a non invasive indicator of transplant rejection. Serum gamma-interferon was studied in nine patients and detected for 14 and 10 consecutive days, respectively in 2 patients. Three of the remaining patients had mild rejection episodes. Of the two patients one rejected the kidney and the other had CMV infection. No correlation was found between gamma-interferon and urine-TXB2. Thus elevated serum gamma-interferon does not interfere with urine i-TXB2.

Animals↗
PubMed1985

Antagonism of 2-5 A-mediated inhibition of protein synthesis in intact cells by 2',5'-(pA)3.

In vitro studies have shown that the translational inhibitory activity of 2-5 A can be blocked by the oligoribonucleotide 2',5'-(pA)3. We have examined the effect of simultaneous introduction of inhibitor and antagonist into intact mouse cells using calcium phosphate coprecipitation. Upon introduction of 10(-4) M 2',5'-(pA)3 and 10(-6) M 2-5 A, inhibition of protein synthesis was prevented. Efficiency of calcium phosphate precipitation of 2-5 A in the presence or absence of 2',5'-(pA)3 was comparable. Introduction of 2',5'-(pA)3 analogs showed that nucleotides which do not bind well to the 2-5 A dependent endonuclease do not prevent 2-5 A inhibitory activity. Thus, 2',5'-(pA)3 functions as an antagonist of 2-5 A in vivo.

Adenine Nucleotides↗
PubMed1985

Regulation of ppp(A2'p)nA-dependent RNase levels during interferon treatment and cell differentiation.

The intracellular effector oligonucleotides ppp(A2'p)nA (n = 2- greater than or equal to 4) regulate the breakdown of RNA by activating ppp(A2'p)nA-dependent RNase. Cellular levels of this RNase were demonstrated to be regulated during differentiation of murine embryonal carcinoma cells. An induction of this RNase by interferon was demonstrated in each of three differentiated cell types (F9 clone 9, PYS, and PSA 5E) by analyzing rRNA breakdown following the introduction of ppp(A2'p)nA into the intact cells. In contrast, in three undifferentiated embryonal carcinoma cell lines (F9, PC13 clone 5, and Nulli 2A) there was little if any ppp(A2'p)nA-dependent RNase either with or without interferon pretreatment. These results were confirmed by affinity labeling of the RNase in cell-free systems. Addition of the proteinase inhibitor, leupeptin, to the cell lysis buffer was necessary to stabilize the RNase against cleavage to discrete breakdown products. Moreover, during differentiation of PC13 clone 5 cells by retinoic acid and N6,O2'-dibutyryl-adenosine 3',5'-monophosphate there was a gradual induction of ppp(A2'p)nA-dependent RNase. The expression of this RNase is, therefore, greatly enhanced during cell differentiation. In addition, the double-stranded-RNA-dependent protein kinase was investigated and was found to be interferon-inducible in all of the cell lines regardless of the state of cell differentiation.

Affinity Labels↗
PubMed1985

Development of transformed phenotype induced by a human ras oncogene is inhibited by interferon.

Mouse IFN inhibited the development of transformed foci in NIH 3T3 cultures transfected with the viral Ha-MuSV(ras) and Mo-MuSV(mos) oncogenes, or with the human bladder carcinoma ras EJ/T24 DNA. IFN treatment five or seven days after transfection was still effective in inhibiting the oncogenic transformation, but did not inhibit significantly the biochemical transformation induced by pSV2-neo or Ecogpt DNA, so that inhibition of ras-induced transformation was not a result of a general effect on the transfection process. Treatment with IFN did not alter the expression of ras EJ/T24 DNA after the transformed phenotype had been established.

Animals↗
PubMed1985

Deficiency of a major myeloid antigen in neutrophils of patients with refractory anemia and excess myeloblasts.

The expression of a major granulocyte-related antigen was assessed on the peripheral blood neutrophils of patients with the syndrome of refractory anemia with excess blasts. Of thirteen patients studied six showed a marked decrease in the number of cells with detectable staining. These results indicate that, although the neutrophils may appear normal by standard morphological criteria in this disease, they may be defective in a major component associated with myeloid maturation.

Anemia, Aplastic↗
PubMed1985

The calcium ionophore A23187 evokes and potentiates antiviral activity of interferon.

Calcium ionophore A23187, which causes a rapid efflux of Ca2+ from cells, evokes an antiviral response in mouse LB, simian COS-1, Hela, human amniotic (U), baby hamster kidney (BHK), and VERO cells against Sindbis (SBV) and vesicular stomatitis (VSV) viruses. The degree of antiviral activity depends on the type of cell, virus, and the dose of A23187. A23187 inhibits the production of infectious VSV; however, VSV particle production was not significantly inhibited as measured by viral RNA and viral proteins. The VSV released from the A23187-treated cells is deficient in VSV glycoprotein (G) and membrane (M) protein. A23187 potentiates the antiviral activity of interferon (IFN) against SBV and VSV in mouse LB and human U cells. It is possible to postulate that a change in intracellular Ca2+ may play an important role in the antiviral activity of IFN.

Animals↗
PubMed1985

Serum alpha interferon and lymphocyte inclusions in systemic lupus erythematosus.

The relationship between serum acid-labile alpha interferon and tubuloreticular inclusions within the cytoplasm of circulating lymphocytes was studied in 46 patients with systemic lupus erythematosus. Elevated levels of interferon (greater than or equal to 8 IU/ml) were found in 17 patients and lymphocyte inclusions in 35. The mean serum interferon concentration in patients with lymphocyte inclusions was significantly higher than in patients without inclusions (17.2 versus 2.4 IU/ml, p less than 0.01). Inclusions were found in 16 of 17 patients with elevated interferon and also in 19 of 29 patients without interferon (p = 0.026). In lupus, serum interferon appears to be a sufficient though not an essential marker for the presence of lymphocyte inclusions.

Humans↗
PubMed1985

Interferon-induced modulation of human ras oncogene expression.

Treatment of NIH 3T3 cells with interferon (IFN) after transfection with human bladder carcinoma EJ/T24 c-Ha-ras1 oncogene DNA caused inhibition of ras-induced cell transformation. Furthermore, the effect of IFN on oncogene expression in an established tumor line was studied. A tumor line of NIH 3T3 (RS485) was transformed by human c-Ha-ras1 activated by a viral long terminal repeat. Treatment of the tumor cells with IFN was associated with a progressive appearance of reverted, flat colonies which exhibited a normal phenotype with respect to morphology and growth. The revertants were well spread, contact inhibited cells; they did not grow in soft agar and were not tumorigenic in nude mice. Revertants retained their normal phenotype, although they contained transfecting human c-Ha-ras1 DNA; but, they produced significantly decreased levels of the onc-encoded protein p21 and c-Ha-ras1 mRNA as compared to RS485 cells.

Animals↗
PubMed1985

Biological and morphological characteristics of phenotypic revertants appearing in interferon-treated mouse cells transformed by a human oncogene.

Phenotypic revertants appearing in interferon-treated mouse cells that had been transformed by an activated human c-Ha-ras1 oncogene (cell line RS485) were tested for several biological properties. The cloned revertants regained the growth characteristics of the untransformed parental NIH 3T3 cell line; unlike RS485 cells the revertants failed to form colonies in soft agar or to form rapidly growing tumors in nude mice. Animals inoculated with RS485 cells developed tumors within one week. In contrast, revertant clonal line 4C3 failed to form tumors four months after transplantation. Revertant 4C8 cells were tumorigenic; however, the developing tumors had increased latency, slower growth rate, and remained smaller than tumors of RS485 cells. Histopathological analysis revealed that revertant-associated fibrosarcomas were less anaplastic, less cellular and had relatively infrequent mitotic figures as compared to fibrosarcomas of RS485 cells. The result suggest the IFN-induced revertants exhibit a significantly less malignant phenotype than their parental transformed cells and that the biological differences are maintained after IFN treatment is discontinued.

Animals↗
PubMed1985

Release of low infectivity vesicular stomatitis virus particles from tunicamycin-treated cells.

The effect of tunicamycin (TM) treatment on the production, glycosylation, morphology and infectivity of vesicular stomatitis virus (VSV) released from mouse (LB), monkey (Cos-1 and VERO), bovine (MDBK), hamster (BHK) and human (HeLa, U and GM2504) cells was investigated. The yield of VSV particles released from TM treated cells, as measured by total viral proteins, was inhibited only 2-10 fold while the infectivity of these particles was greatly reduced (10-1000 fold). The morphology of VSV particles formed in the presence of TM appeared similar to that of VSV particles released from untreated cells as demonstrated by electronmicroscopy. Analysis of intracellular and extracellular virus specific proteins by SDS polyacrylamide gel electrophoresis revealed that TM blocks the glycosylation of VSV glycoprotein G in all cells tested. These results suggest that inhibition of glycosylation of VSV G protein could affect the biological infectivity of the VSV particle released from the treated cells.

Animals↗
PubMed1984

Biochemical correlates of phenotypic reversion in interferon-treated mouse cells transformed by a human oncogene.

Mouse interferon (IFN) induced a phenotypic reversion in RS 485, a clonal line of NIH 3T3 oncogenically transformed by a human c-Ha-rasl gene activated by Ha-MuSV long terminal repeats (LTRs). Transfected c-Ha-ras DNA, unchanged in quantity and distribution, as compared to the parental RS 485 transformed cells, was still present in these revertants; however, there was a significant reduction in the amount of c-Ha-ras specific mRNA and of c-Ha-ras specified p21 protein.

Animals↗
PubMed1984

Interferon-related leukocyte inclusions in acquired immune deficiency syndrome: localization in T cells.

Blood samples from a series of 12 patients with Kaposi's sarcoma or infectious complications of the acquired immunodeficiency syndrome (AIDS) and from 18 homosexual contacts of AIDS patients were screened for interferon-related tubuloreticular inclusions (TRI) in circulating leukocytes. In the AIDS patients, TRI were detected by transmission electron microscopy in 1.5 to 10% of mononuclear cell sections. They were most frequent in patients with a decreased fraction of T helper cells and T4/T8 ratios less than 0.2. Only rare TRI-positive sections were found in 3/12 homosexual contacts with lymphadenopathy and 1/6 asymptomatic contacts. Serum interferon was found to be elevated in each AIDS case tested, but was not a sufficient condition for detection of TRI in homosexual contacts. Active DNA virus infections, including cytomegalovirus, were common to the AIDS cases and possibly contributed to the TRI pathogenesis. Localization of TRI in T suppressor/cytotoxic cells was demonstrated with monoclonal anti-Leu 2a antibodies. The pathophysiologic significance of interferon stimulation with formation of TRI in immunocompetent cells requires further investigation.

Acquired Immunodeficiency Syndrome↗