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Biomedical subjects

L Diamond

Publications and source records attributed to L Diamond.

At least 145 records · Page 8Linked to original sources
PubMed1976

Differences between murine C1300 neuroblastoma clones detected by rosette formation with nerve growth factor-coated sheep red blood cells.

The expression of receptors for nerve growth factor (NGF) on the cell surface was assayed by rosette formation with ligand-coated sheep red blood cells (SRBC). Cell clones derived from the murine C1300 neuroblastoma and from hybrids between a neuroblastoma clone and L cell clones showed a wide variation in the capacity to form rosettes with NGF-coated SRBC. All the neuroblastoma, L cell and hybrid clones formed rosettes with phytohemagglutinin-coated SRBC and none formed rosettes with cytochrome c- or ferritin-coated SRBC or with SRBC not coated with ligand.

Animals↗
PubMed1976

In vitro stimulation of mouse lymphoid cells by C1300 neuroblastoma cells or tumor membrane extracts.

Spleen lymphoid cells from A/J mice recognize specific antigenic differences on the surface membranes of syngeneic C1300 neuroblastoma cells and incorporate 3H-thymidine into DNA in unidirectional mixed cell cultures in the absence of isologous serum. The response requires an optimal ratio of responder to stimulator cells, and is detectable after 24 h. It is specifically blocked by the presence of a papain-solubilized crude membrane extract from the same neuroblastoma cells, the extent of inhibition being dependent on the concentration of the extract and the time when it is added to the cultures. Spleen cells from mice bearing the neuroblastoma respond earlier and incorporate more 3H-thymidine than cells from unsensitized mice. The enhanced response of the primed spleen cells to the stimulator cells is similar to a secondary immune response and can be induced by soluble crude tumor extracts in the absence of stimulator cells.

Animals↗
PubMed1976

Effect of 7,8-benzolfavone on the formation of benzo(alpha)pyrene-DNA-bound products in hamster embryo cells.

The hydrocarbon-deoxyribonucleoside products present in enzyme digests of DNA from hamster embryo cultures that had been treated with[3H]-benzo[alpha]pyrene (BP) were isolated by chromatography on Sephadex LH20 columns. The products isolated from cells treated with 7,8-benzoflavone (7,8-BF) for 18 h prior to the addition of [3H] BP were indistinguishable from the products isolated from untreated cultures, but the amounts of these products decreased with increasing concentrations of 7,8-BF. The amount of BP metabolized was also decreased in 7,8-BF-treated cultures. The decrease in the amounts of hydrocarbon-deoxyribonucleoside products per mg DNA was logarithmic with respect to the decrease in BP metabolism. The findings are consistent with the hypothesis that 7,8-BF inhibits both an initial and a later metabolic step involved in the conversion of BP to a reactive species that binds to cellular DNA.

Animals↗
PubMed1975

Drug absorption VII: influence of mesenteric blood flow on intestinal drug absorption in dogs.

Intestinal absorption of sulfaethidole and haloperidol was determined using an in situ canine intestinal preparation. Intestinal absorption of sulfaethidole was determined at three or four mesenteric blood flow rates in each dog, ranging from unaltered flow (100%) to no flow (0%). A relatively small change in absorption rate occurred when the splanchnic blood flow rate was decreased about 35%. Further reductions in mesenteric blood flow resulted in progressive impairment of sulfaethidole absorption. The simultaneous measurement of sulfaethidole intestinal disappearance and appearance in blood indicates that sulfaethidole disappearance is equivalent to absorption. Haloperidol absorption also decreased with decreased intestinal perfusion but differed from sulfaethidole in that membrane storage of haloperidol appeared to take place during its absorption.

Animals↗
PubMed1975

Oral inhalation system for exposing rabbits to cigarette smoke.

An oral inhalation system for exposing rabbits to cigarette smoke has been developed. The essential components of the system comprise a smoke delivery device that adapts to the oral cavity, a molded face mask, and a sealable body enclosure. The functional capability of the system has been validated by detecting the presence of nicotine in plasma and by measuring the deposition of dotricontane labeled with radioactive carbon (14C) in lungs after exposure to cigarette smoke.

Animals↗
PubMed1975

Isolation of variant cells from SV-40 transformed human diploid fibroblasts.

Variant cell lines that are sensitive to density-dependent inhibition of growth have been isolated from three of four SV40-transformed human fibroblast cell lines. Variants were isolated by plating the transformed cells at low density, by treating them with 5-fluorodeoxyuridine, or by growing them on glutaraldehyde-fixed monolayers of normal cells. The variant cell lines, isolated at a frequency of about 2% of all cells forming colonies after treatment, were initially recognized by colonial morphology, and the variant pheno-types were confirmed, after subculturing, by saturation-density determinations. The variant cell lines reach saturation densities that are 40% or less than those of the parent cell lines, and plate in soft agar medium at reduced efficiency, compared with the parent cells. They retain SV40 T antigen. The modal chromosome numbers of two of the variant cell lines were increased, compared with those of the parent cell lines; two other variants were indistinguishable in chromosome number from the parent cells. Stability of these properties over a 6-month period was demonstrated with two of the variants.

Cell Line↗
PubMed1975

Experimental study of a potential anti-asthmatic agent: SCH 15280.

A forced oscillations technique for measuring total respiratory system resistance was used to quantitate the bronchomotor activity of Sch 15280: (5[4-(N-methyl)-piperidylidine]5H-[1]-benzopyrano[2,3,b]-pyridine maleate) and to compare its potency to that of standard bronchodilator agents. By the intravenous route, Sch 15280 was 48 times more potent than aminophylline and 1/78 as potent as atropine in inhibiting methacholine-induced bronchoconstriction in rabbits. In cats Sch 15280 was 1/12 as potent as ephedrine in inhibiting histamine-induced bronchoconstriction and had a greater protective activity against histamine-induced bronchoconstriction and had a longer duration of action than 0.5% solution of isoproterenol. Statistical tests of parallelism revealed a significant difference between the log dose-response curves of Sch 15280 and ephedrine but not between those of Sch 15280, atropine and aminophylline. The results suggest that Sch 15280 can act via, a nonadrenergic mechanism to block both histaminergically and cholinergically mediated responses in the tracheobronchial tree. This pharmacologie profile may have important therapeutic application in the type I immediate hypersensitivity reactions of man.

Adrenergic beta-Antagonists↗