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Biomedical subjects

L Kahn

Publications and source records attributed to L Kahn.

At least 19 recordsLinked to original sources
PubMed1995

Preoperative factors of prognostic significance in gastric cancer.

This study was undertaken to investigate the ability of local anatomical and primary histological features of gastric cancers, as well as DNA analysis, to predict prognosis. Using multivariate analysis, results indicate that location of a tumor in the gastric cardia, poor differentiation, involvement of adjacent organs, and aneuploidy are all independent predictors of survival. All of the factors studied can be determined by endoscopic procedures preoperatively on patients with gastric cancers and could be helpful in selecting some patients for perioperative adjunctive therapies.

Adenocarcinoma↗
PubMed1992

Expression of the amiloride-blockable Na+ channel by RNA from control versus aldosterone-stimulated tissue.

The amiloride-blockable Na+ channel was expressed in Xenopus oocytes injected with total RNA isolated from the toad urinary bladder. This system was used to investigate mechanisms that mediate the natriferic action of aldosterone. Incubation of the epithelium with aldosterone for 3 h doubled its channel activity but did not increase the ability of isolated RNA to express functional channels in oocytes. A 20-h incubation with the hormone produced an additional increase of Na+ transport across the intact epithelium and also augmented the channel activity expressed in oocytes by nearly 10-fold. The data are in agreement with our model that aldosterone enhances the apical Na+ permeability of tight epithelia by a short term activation of pre-existing channels, followed by chronic induction of new channel protein. Blocking methyl transfer reactions, previously shown to inhibit the natriferic action of aldosterone in tight epithelia, did not alter the basal or aldosterone-induced response in oocytes.

Aldosterone↗
PubMed1992

Prognostic factors in node-negative breast cancer.

One hundred patients with node-negative breast cancer were examined to analyze the influence of tumor size, nuclear grade, and DNA content determined by flow cytometry on overall survival. Patients with diploid cancers lived significantly longer than those with aneuploid cancers (126 +/- 8 vs 80 +/- 11 months). Patients with an S-phase fraction less than 10% lived significantly longer than those with S-phase fractions 10% or greater (122 +/- 8 vs 85 +/- 10 months). Tumor size had the major impact on survival, and multivariate analysis of variance by the Cox proportional hazards model showed the greatest effect on prognosis. Tumor grade did not significantly influence overall survival.

Breast Neoplasms↗
PubMed1988

Humanities now?

Explore the source record for details and available documents.

Education, Medical↗
PubMed1986

Effect of an inhibitor of DNA methylation on T cells. I. 5-Azacytidine induces T4 expression on T8+ T cells.

Maturing thymocytes express a series of cell surface glycoproteins which can be identified by monoclonal antibodies. The stage II or common thymocyte expresses the phenotype T4+T8+T6+T3-. In response to unknown signals, but presumably involving interactions with products of the major histocompatibility complex, the thymocyte suppresses either the T8 or T4 gene, becoming committed to the T4+T8- or T4-T8+ phenotype. With maturation, the thymocyte also becomes T6-T3+. To study whether DNA methylation may be involved in regulating expression of these determinants in mature T cells, we treated cloned interleukin 2-dependent T8- and T4-bearing T cells with 5-azacytidine (5-azaC), a nucleoside analog which inhibits methylation of newly synthesized DNA. In this report, we show that T8+ T cells treated with 5-azaC express the phenotype T8+T4+T6-T3+. Treatment of the same cells with hydroxyurea, an inhibitor of DNA synthesis, failed to induce T4 on T8+ cells. These results suggest that expression of the T4 gene may be suppressed by DNA methylation in mature T8+ cells.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1983

High-dose methotrexate in small cell lung cancer. Lack of efficacy in preventing CNS relapse.

Few studies have incorporated high-dose methotrexate (MTX) with leucovorin rescue in the treatment of small cell lung cancer (SCLC). Potentially therapeutic levels of MTX can be achieved in the central nervous system (CNS) by systemic administration of high doses of this drug. Utilizing a combination chemotherapy program of Adriamycin, vincristine, cyclophosphamide, and methotrexate, 31 patients were sequentially assigned to receive either low-dose MTX (40 mg/m2), or high-dose MTX (500 mg/m2) with leucovorin rescue. Radiation therapy to the primary site was also administered. At these dosage levels there were no statistically significant differences in response rate or survival between the two groups. High-dose MTX did not prevent the appearance of CNS disease; there being 2/15 and 3/15 CNS relapses in the HD MTX and LD MTX treated groups, respectively. The occurrence of CNS disease did not significantly affect overall survival as compared to patients not similarly affected.

Aged↗