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Biomedical subjects

S Reich

Publications and source records attributed to S Reich.

At least 73 records · Page 4Linked to original sources
PubMed1990

Modification of dinitrogenase reductase in the cyanobacterium Anabaena variabilis due to C starvation and ammonia.

In the heterocystous cyanobacterium Anabaena variabilis, a change in nitrogenase activity and concomitant modification of dinitrogenase reductase (the Fe protein of nitrogenase) was induced either by NH4Cl at pH 10 (S. Reich and P. Böger, FEMS Microbiol. Lett. 58:81-86, 1989) or by cessation of C supply resulting from darkness, CO2 limitation, or inhibition of photosystem II activity. Modification induced by both C limitation and NH4Cl was efficiently prevented by anaerobic conditions. Under air, endogenously stored glycogen and added fructose protected against modification triggered by C limitation but not by NH4Cl. With stored glycogen present, dark modification took place after inhibition of respiration by KCN. Reactivation of inactivated nitrogenase and concomitant demodification of dinitrogenase reductase occurred after restoration of diazotrophic growth conditions. In previously C-limited cultures, reactivation was also observed in the dark after addition of fructose (heterotrophic growth) and under anaerobiosis upon reillumination in the presence of a photosynthesis inhibitor. The results indicate that modification of dinitrogenase reductase develops as a result of decreased carbohydrate-supported reductant supply of the heterocysts caused by C limitation or by increased diversion of carbohydrates towards ammonia assimilation. Apparently, a product of N assimilation such as glutamine is not necessary for modification. The increase of oxygen concentration in the heterocysts is a plausible consequence of all treatments causing Fe protein modification.

Aerobiosis↗
PubMed1990

In vivo biological response to recombinant interferon-gamma during a phase I dose-response trial in patients with metastatic melanoma.

Interferon-gamma (IFN gamma), as produced by recombinant DNA technology, has shown a wide range of immunomodulatory activity in vitro and in vivo. Clinical studies have attempted to establish a dose-response relationship to define optimal dosage ranges for induction of effector cell function and host response in patients with cancer. We conducted a randomized trial to test the in vivo biologic activity of five daily dosages ranging from 3 to 3,000 micrograms/m2, administered by daily 2-hour bolus injection or by continuous infusion for 14 days. We demonstrate comparable immunobiologic effects of recombinant IFN gamma (rIFN gamma; Biogen, Inc, Cambridge, MA) administered by these two schedules at the various dosages tested, and have defined a relationship of dose to biologic response over this 3-log10 dose range. Oligo 2'5' adenylate synthetase (2'5'As) induction, natural-killer (NK) cell activity, and T-cell subset distribution (heightened T helper/suppressor ratio) showed the most consistent treatment-associated changes and the greatest immunobiologic effects at dosages of 300 to 1,000 micrograms/m2. Mononuclear cell DR and DQ antigen expression showed no consistent dose-related treatment effect. The relevance of the phenotypic, functional, and enzymologic effects observed in this trial to any clinical antitumor effects of IFN gamma in cancer therapy must now be established.

2',5'-Oligoadenylate Synthetase↗
PubMed1990

Effect of cyclosporine A and methylprednisolone on the graft-versus-leukemia effects across major histocompatibility barriers in mice following allogeneic bone marrow transplantation.

The effect of post-transplant immunosuppressive agents used in anti-GVHD prophylaxis on leukemic relapse was tested using a murine model of originally spontaneous, subsequently transplantable and non-immunogenic B cell leukemia (BCL1). (BALB/c x C57BL/6)F1 mice inoculated with 10(7) BCL1 cells were conditioned by total lymphoid irradiation (TLI) (1600 cGy), cyclophosphamide (200 mg/kg) or total body irradiation (TBI) 750 cGy and reconstituted with C57BL/6 (C57) bone marrow cells (30 x 10(6] or 10 x 10(6) bone marrow cells with additional 2 x 10(6) donor-type spleen cells, respectively. Mice were treated by cyclosporine A (CSA) 20 mg/kg i.p., or methylprednisolone (MP) 10 mg/kg i.p. for 10 days each and one group of controls received no post-transplant therapy. Stable chimerism was documented in all recipients with greater than or equal to 90% donor-type C57 cells in the peripheral blood. Eighty-nine percent of the mice treated by CSA following conditioning with TLI developed leukemia within 70 days, whereas none of the MP-treated mice and none of untreated chimeras showed any evidence of leukemia for more than 150 days. Adoptive transfer experiments using 10(5) spleen cells obtained from recipients conditioned with TBI were done to monitor residual leukemic cells following different post-transplant treatments. Eight-five percent of recipients of spleen cells obtained from mice treated with CSA developed leukemia in contrast with 33% and 25% when spleen cells were obtained from mice treated with MP or untreated controls, respectively (p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Shiley INFUSAID Pump technology.

Totally implantable drug delivery devices have been shown to be safe and effective in the delivery of drugs both systemically and regionally. Applications have been developed for continuous infusions of drugs and are currently being developed for variable flow rates with more sophisticated programmable pumps. Some of the potential benefits of such devices include improved drug efficacy with reduced systemic toxicities, more controlled dosing of drugs, improved quality of life, delivery of proteins and peptides, and individualized patient dosing. The potential exists for creating biofeedback closed loop therapies for diabetes, cardiovascular diseases, and some central nervous system diseases in the future.

Catheterization↗
PubMed1986

Effects of nicotine on body weight, food intake and brown adipose tissue thermogenesis.

Chronic treatment with nicotine results in reduced body weight gain without a change in food intake. To evaluate the role of brown adipose tissue (BAT) thermogenesis in this effect of nicotine, male Sprague-Dawley rats were chronically treated (3X daily, IP) over a 14 day period with either saline, 0.8 mg/kg nicotine, 10 mg/kg caffeine or a combination of 0.8 mg/kg nicotine and 10 mg/kg caffeine and were pretreated (once daily) with either saline or 20 mg/kg nadolol, a long-acting beta-adrenergic receptor blocker. Nicotine significantly reduced body weight gain but not food intake and nadolol did not reverse the effect of nicotine on body weight gain. To evaluate whether nicotine induces BAT thermogenesis, rats were injected IP with either saline or 0.8, 1.2 or 1.6 mg/kg nicotine hydrogen tartrate, with 5 mg/kg dl-phenylpropanolamine (dl-PPA) or with a combination of 0.8 mg/kg nicotine and 10 mg/kg caffeine with interscapular BAT (IBAT) temperatures recorded for 30 minutes after injection. No dose of nicotine produced a change in IBAT temperature whereas a combination of caffeine and nicotine produced a temperature increase in IBAT (0.95 degree C) 63% of that induced by 5 mg/kg dl-PPA. These data suggest that changes in body weight gain induced by nicotine treatment are not the result of an action of nicotine on BAT thermogenesis.

Adipose Tissue, Brown↗
PubMed1984

Intraocular-lens-endothelial interface: adhesive force measurements.

An instrument for measuring the force of adhesion between intraocular lens materials and the endothelium of excised rabbit corneas was constructed. The adhesion force was measured for polymethylmethacrylate (PMMA), polyhydroxyethylmethacrylate (PHEMA), Duragel (amino-polyamide hydrogel), PMMA surface grafted with polyvinylpyrrolidone, and PMMA surface treated with sodium hyaluronate (Healon). The force of adhesion was reduced considerably when the PMMA surface was modified with a hydrophilic polymer coating. This is consistent with previous studies showing reduced endothelium cell damage for hydrophilic polymer coated intraocular lenses. Adhesive forces were also decreased by addition of polyvinyl alcohol or gelatin to the saline solution in which the corneas were immersed. Extension of this type of measurement to pericardium, vascular endothelium, and peritoneum surfaces may also be important to understand tissue damage problems in general surgery.

Animals↗
PubMed1984

Cell-substrate interaction. A method for evaluating the possible correlation between metastatic phenotype and cell surface energy.

The interfacial energy of the non-attached to substrate cell surface was analysed in tumor cell variants of the K-1735 melanoma and UV-2237 fibrosarcoma series, which exhibit distinct metastatic phenotypes. The highly metastatic cell variants exhibited a two-fold increase in the ability to form rapid cell substrate interactions, as compared with their low-metastatic counterparts. These results further highlight the possible role of cell adhesiveness in the process of metastasis.

Animals↗
PubMed1982

Myocardial rupture after myocardial infarction. Detection by multi-gated image-acquisition scintigraphy.

Myocardial rupture following infarction usually is an acute and dramatic event. Rarely, it may take a subacute course, allowing surgical treatment. We report herein a case of subacute rupture of the heart in a 54 year old patient with acute myocardial infarction. The rupture was diagnosed by the appearance of a radiopaque halo around the heart during radionuclide ventriculography. The patient subsequently underwent surgical resection of a large anterolateral aneurysm and a 2 inch long rupture of the myocardium and survived. Clinical suspicion, prompt diagnosis, and surgical intervention are important in the management of this relatively unusual complication of infarction.

Heart Aneurysm↗
PubMed1975

Twenty-four hour left ventricular bypass with a centrifugal blood pump.

A new centrifugal blood pump system has been developed for left ventricular bypass by the addition of non-thrombogenic blood surface materials and an ultrathin-walled cannula for the retrograde cannulation of the left ventricle. Partial LV bypass at 3 to 6 L/min was undertaken in 55 calves without thoracotomy. In 20 it was continued for 24 hours, with 13 survivors who were eventually sacrificed. Eleven of the last 14 experiments were completed without mishap. Heparin was employed only during pump insertion. Hematologic changes were limited to moderate platelet depression, and tolerable hemolysis (average serum level 21 mg% in the last 13 experiments). Normal clotting parameters and the absence of significant fibrin split product formation correlated with the absence of gross thrombosis and few minor renal emboli observed at autopsy. This pump system appears to have several advantages over previously described equipment for LV bypass.

Animals↗