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Biomedical subjects

M Feldman

Publications and source records attributed to M Feldman.

At least 469 records · Page 26Linked to original sources
PubMed1978

In vitro sensitization of human lymphocytes against histiocytic lymphoma cell lines. II. Characterization of two different effector activities and of suppressor cells.

Peripheral blood lymphocytes (PBL) from normal human donors were tested for natural killing (NK) activity and for two types of in vitro induced cytotoxicity against allogeneic diffuse histiocytic lymphoma (DHL) cell lines. Culture-induced cytotoxic (CIC) activity developed in cultures of unseparated PBL incubated in the presence of fetal bovine serum (FBS) but not in the presence of human serum (HS). The CIC mediating effector cells were removed by nylon wool adherence, whereas the NK cells were not. A second type of in vitro induced cytotoxicity was obtained by specific sensitization against DHL cells (SIC). The SIC effector cells were not retained by nylon wool. SIC was manifested after sensitization in medium containing HS but not in FBS-containing medium unless nylon wool adherent cells were removed before sensitization. The lack of SIC in the presence of FBS appeared to be due to nylon wool-adherent suppressor cells. Such suppressor activity was also removed by plastic adherence or elimination of phagocytic cells. CIC and suppressive activity were found to be mediated by different cell populations.

Cell Line↗
PubMed1978

The ultrasound guided 32P test.

The accurate and early diagnosis of intraocular malignant melanoma in eyes with opaque media remains a diagnostic problem. Ultrasonography and the radioactive phosphorus (32P) uptake test have been used separately as modalities for diagnosis of choroidal melanoma. However, their combined use has received limited attention. This report presents our experience in 5 cases with the combined use of a contact B-scan ultrasound unit and a posterior eye probe. In all cases we were able to accurately perform the 32P uptake test with simultaneously ultrasound visualization of the tumor and the probe.

Aged↗
PubMed1977

Effect of low-dose propantheline on food-stimulated gastric acid secretion: comparison with an "optimal effective dose" and interaction with cimetidine.

We evaluated the widely held notion that anticholinergic drugs must be used in near toxic doses to inhibit gastric acid secretion effectively. Nine patients with duodenal ulcer were studied after a low dose (15 mg) and after a near toxic dose (averaging 48 mg) of the anticholinergic, propantheline. Mean (+/- S.E.) inhibition of food-stimulated acid secretion was identical with the two doses of propantheline: 29 +/- 10 and 29 +/- 11 per cent, respectively. In addition, when 15 mg of propantheline was combined with the histamine H2-receptor antagonist, cimetidine, acid secretion was suppressed to a greater degree than with either drug alone. A low dose of propantheline is as effective as a near toxic dose in suppressing food-stimulated acid secretion and augments the inhibitory effect of cimetidine.

Adult↗
PubMed1977

Enhancing lymphocytes in spleens of tumor-bearing mice: affinity chromatography on insolubilized histamine.

Spleen cells from C57BL mice carrying the metastatic Lewis lung carcinoma (3LL) developed a transient cytotoxic response towards the tumor shortly after tumor transplantation. Later on, the cytotoxic activity was lost and enhancing lymphocytes could be demonstrated in the spleens of the tumor-bearing mice (TBM). Spleen cells that were transferred together with tumor cells into syngeneic recipients enhanced tumor growth. The enhancing activity could be eliminated by the removal of a cell population that bound to histamine/rabbit serum albumin/Sepharose (HRS). The adherent population was enriched for enhancing lymphocytes, since it enhanced tumor growth more than the unfractionated population. The non-adherent cells, on the other hand, lost their enhancing activity in vivo and were sometimes protective against tumor growth. In addition, these cells manifested in vitro cytotoxicity against tumor cells. Hence the suppression of the cytotoxic expression in TBM is, at least in part, due to suppressor lymphocytes that bind to unsolubilized histamine. These cells seem to enhance tumor growth by suppressing host reactivity. Thus the enhancing lymphocyte populations can be separated into two subpopulations, of which one is enriched while the other is depleted of suppressor cells.

Animals↗
PubMed1977

Estrogen-binding protein from rat preputial gland: purification and characterization.

Cytosol from the rat preputial gland has been shown to contain a protein which binds both estrone and estradiol. The protein, after a 26-fold purification from the cytosol of female Sprague-Dawley rats, migrated as one band during electrophoresis in sodium dodecyl sulfate on acrylamide gel. The electrophoretic mobility indicated a molecular weight of 15,000. The association constant for estrone as determined by equilibrium dialysis was 1.2 X 10(7) M-1, while that for 17beta-estradiol was 3.3 X 10(6) M-1. Progesterone, cortisol, testosterone, or diethylstilbestrol did not bind to the purified protein, whereas 17alpha-estradiol or estriol bound only slightly. In the presence of retinoic acid, but not retinol, the binding of estrone was reduced. Optimum binding for estrone was at pH 6.5 to 8.5.

Animals↗
PubMed1977

In vitro studies on H-2-linked unresponsiveness to synthetic polypeptides. III. Production of an antigen-specific T helper cell factor to (T,G)-A--L.

The in vitro production, assay and partial characterization of an extremely potent antigen-specific T helper cell factor to poly-L-(Tyr, Glu)-poly-DL-Ala--poly-L-Lys [(T,G)-A--L] which may be an important physiological mediator of T cell function in vivo is described. The factor has an antigen-binding site, Ia and Ig-like determinants on the same molecular complex. The response to (T, G)-A--L is under H-2-linked Ir gene control, some but not all low responder haplotypes will produce the factor.

Animals↗
PubMed1977

In vitro activation of the in vivo colony-forming units of the mouse yolk sac.

Experiments were performed to investigate the presence of colony-forming units (CFU) in the mouse embryonic yolk sac during the developmental period in which the yolk sac is the sole hemopoietic organ. Injection of yolk sac cell suspensions from normal embryos into syngeneic, lethally irradiated adult recipients evoked a very low number of spleen colonies. However, prior cultivation of yolk sacs in vitro caused a dramatic increase in the spleen colony-forming capacity--as high as 84-fold--following 48 hours in culture. The yolk sac origin of the spleen colonies was confirmed by: (a) Chromosomal marker analysis; (b) dose-response analysis; (c) demonstrating that the above colonies were not of endogenous origin induced by the mere injection of grafted cells. We conclude that the yolk sac contains many precursors of colony-forming cells which though undetectable by immediate grafting apparently become activated in culture by an as yet unknown induction process.

Animals↗
PubMed1977

Macrophage-mediated in vitro sensitization of T-lymphocytes. I; Detection of murine leukemia virus-associated antigens.

Cytotoxic effector T-lymphocytes were produced in vitro by sensitization of spleen cells on monolayers of syngeneic macrophages that had been fed with radiation leukemia virus-containing cell extracts or with supernatants of virus-producing cell cultures. The sensitized lymphocytes were cytotoxic to cell lines that expressed viral antigens. Secondary mouse embryo fibroblasts were little affected. Sensitization via macrophages appeared to be a useful system for identification of viral antigens on surfaces of various target cells, as well as for tests of the protective effect of such lymphocytes against tumor growth in vivo.

Animals↗
PubMed1977

A comparison of HLA data of the North American black with African black and North American caucasoid populations.

For purposes of genetic comparison, the available HLA data on United States and African Black, together with United States Caucasoid populations, are summarized. Antigen frequencies and pairwise linkage disequilibria are presented for the HLA-A, -B and -C loci in Black populations typed for the 1975 Histocompatibility Testing Workshop. The Black population samples comprise 356 North American Blacks and 411 African Blacks of whom 222 were Bantu. These are compared with a sample of 503 American Caucasoids. All significant linkage disequilibria between the A and B loci found in North American Blacks were also present in the North American Caucasoids. Between the B and C loci, Bw35 and Cw4 were in strong linkage disequilibrium in all groups. Significantly stron association between the A and C loci (Aw28 with Cw3) were observed only in the African Blacks. There were unique disequilibria both in the American Caucasoids and African Blacks. Although the frequencies of many antigens in U.S. Blacks lie between those in Africans and U.S. Caucasoids, there are exceptions such as Aw33, Bw35, Cw4.

Africa↗
PubMed1977

Studies on the role of cephalic-vagal stimulation in the acid secretory response to eating in normal human subjects.

These experiments were performed to determine the importance of cephalic-vagal stimulation in the acid secretory response to eating in normal human subjects. Cephalic stimulation was induced by a modified sham feeding (MSF) technique, during which subjects chewed and expectorated appetizing food. The response to MSF was compared with that to gastric distention with 600 ml NaCl, glucose, or food. In addition, we measured the extent to which cephalic stimulation augments acid secretion that has been stimulated simultaneously by these other mechanisms. Our conclusions are as follows: (a) cephalic stimulation accounts for approximately one-third of the acid secreted when all mechanisms act simultaneously (food-distention plus MSF); (b) within the limits imposed by the maximal secretory capacity, the response to MSF is approximately the same, regardless of whether acid secretion is otherwise unstimulated or is stimulated simultaneously by gastric distention with NaCl, glucose, or food; and (c) gastric distention prolongs the response to cephalic stimulation.

Adult↗
PubMed1977

In vitro sensitization of human lymphocytes against histiocytic lymphoma cell lines. I. Primary sensitization of lymphocyte subpopulations.

Peripheral blood lymphocytes from normal donors expressed spontaneous cytotoxic activity against human diffuse histiocytic lymphoma cell lines. In the unfractionated state, they could not be further sensitized in vitro against these cell lines. By applying cell separation techniques before culture, subpopulations of lymphocytes were obtained which could be sensitized in vitro and manifested cytotoxic activity against human histiocytic lymphoma cells. Three methods of separation were found effective: E rosette enrichment; elimination of Fc receptor positive cells; and removal of nylon wool adherent cells. Under these conditions, cross-reactive cytotoxicity was observed against non-neoplastic lymphoblastoid cell lines, but not against normal lymphocytes.

Cell Line↗
PubMed1976

Fragments formed by the side chain cleavage of a 20-aryl analog of 20alpha-hydroxycholesterol by adrenal mitochondria.

An analog of 20alpha-hydroxycholesterol, (20R)-20-phenyl-5-pregnene-3beta,20-diol, which is completely substituted at C-22 was prepared with radioisotopes at various positions. The analog labeled with 3H at C-M and 14C at C-4 and C-IU was converted into radioactive pregnenolone by an enzyme preparation derived from adrenal mitochondria. Cleavage of the phenyl analog labeled with 3H in the aromatic ring by the same enzyme preparation led to the formation of [3H]phenol. Using the substrate doubly labeled with 14C at C-4 and 3H in the aromatic ring, it appeared that the products of the reactions, pregnenolone and phenol, were formed in equal amounts. During incubation of the side chain labeled substrate, another labeled fragment was formed. It was identified as acetophenone, a product resulting from cleavage of the C17,20 bond. The steroidal fragment corresponding to this C8 ketone was traced using nuclear label analog. From its nonpolar chromatographic properties it appears to be a C-17-deoxy-C19 steroid.

Adrenal Medulla↗