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Biomedical subjects

L Cohen

Publications and source records attributed to L Cohen.

At least 451 records · Page 25Linked to original sources
PubMed1983

Magnesium sulfate and digitalis-toxic arrhythmias.

Seven patients with congestive heart failure receiving long-term diuretic treatment (more than three years) experienced idionodal tachycardia in the presence of apparently normal serum digoxin levels. Intravenous bolus administration of magnesium (Mg) sulfate, followed by intramuscular Mg repletion, abolished the digitalis-toxic arrhythmia. The finding of decreased lymphocyte Mg and potassium contents proved the existence of cellular Mg depletion associated with normal serum Mg levels in five patients and with hypomagnesemia in the other two. Decreased cellular Mg content with normal serum Mg level predisposes to digitalis-toxic arrhythmias.

Aged↗
PubMed1983

Methods utilizing cell-free protein-synthesizing systems for the identification of recombinant DNA molecules.

Herein we outline three methods that, when coupled with cell-free protein synthesis, permit the identification of recombinant DNA molecules encoding specific polypeptides. RNAs enriched by fractionation on methylmercury hydroxide agarose gels are used to prepare sequence-specific probes. Recombinant DNA clones thus identified are further characterized as to their encoded polypeptides by either hybrid selection or hybrid arrest of translation.

Actins↗
PubMed1983

RTOG Phase I study on fast neutron teletherapy for squamous cell carcinoma of the esophagus.

From August, 1977, through January, 1981, the Radiation Therapy Oncology Group sponsored a Phase I study (RTOG 77-09) on the use of fast neutrons for treating inoperable squamous cell carcinomas of the esophagus. A total of 39 evaluable patients were treated with curative intent using either fast neutrons alone or in combination with low LET irradiation as part of a mixed beam fractionation scheme. Actuarial survival curves are presented for both the "neutrons alone" and the "mixed beam" treatment groups. There was no significant survival difference between these groups of patients. The projected survival at two years is less than 10%, which is comparable with megavoltage photon results for an unselected series of patients. The size of the primary lesion and the initial Karnofsky performance status were found to be the most important prognostic indications for prolonged survival. Sixteen of 39 patients were felt to have achieved local clearance of their tumor at some time during their follow-up with the median time until a local recurrence being 17 months. Treatment related complications and patterns of metastatic spread are discussed. In general, it appeared that the response of large tumors to neutron irradiation resulted in necrosis and fistula formation. In many cases this was accompanied by persistent/recurrent tumor within the high dose radiation volume.

Aged↗
PubMed1983

Iso-effect tables for tolerance of irradiated normal human tissues.

Available literature on radiation injury to human tissues (lung, brain, kidney and intestine) was surveyed. A parameter search program (RAD3) was used to derive best-fitting cell kinetic parameters, on the assumption that radiation injury arises from depletion of parenchymal cells in the irradiated organs. From these parameters iso-effect tables were constructed for a wide range of treatment schedules, including daily treatment as well as fractionation at longer intervals, for each tissue. The tables provide a set of limiting doses, above which the risk of radiation injury becomes substantial. Tolerance limits and dose-time-factors were substantially different in the four tissues. It is concluded that computed iso-effect tables provide a more reliable guide to treatment than conventional time-dose equations.

Brain↗
PubMed1983

Iso-effect tables and therapeutic ratios for epidermoid cancer and normal tissue stroma.

Available literature on radiation injury to normal tissue stroma and ablation of epidermoid carcinoma was surveyed. Computer programs (RAD3 and RAD1) were then used to derive cell kinetic parameters and generate iso-effect tables for the relevant tissues. The two tables provide a set of limiting doses for tolerance of normal connective tissue (16% risk of injury) and for ablation of epidermoid cancer (16% risk of recurrence) covering a wide range of treatment schedules. Calculating the ratios of normal tissue tolerance to tumor control doses for each treatment scheme provides an array of therapeutic ratios, from which appropriate treatment schemes can be selected.

Carcinoma, Squamous Cell↗
PubMed1983

Human monocytes, B lymphocytes, and non-B lymphocytes each have structurally unique Fc gamma receptors.

Human Fc gamma-binding macromolecules were isolated from subpopulations of mononuclear cells by repetitive affinity chromatography. Mononuclear cells, nylon wool-filtered cells, plastic-nonadherent cells, and plastic-adherent cells from normal donors were radiolabeled by using 125I and lactoperoxidase. Washed cells were solubilized in 1% NP-40 buffer containing proteinase inhibitors at 0 degrees C. Fc gamma receptors were purified on human IgG-Sepharose columns by use of the repetitive affinity chromatography procedure. Analysis by SDS-polyacrylamide gel electrophoresis demonstrated only a 52,000 to 58,000 Mr Fc gamma receptor from nonadherent cell populations. Both rosetting and nonrosetting subpopulations of non-B lymphocytes expressed the 52,000 to 58,000 Mr receptor. The predominant Fc gamma receptor isolated from plastic-adherent cells was a 60,000 to 68,000 Mr macromolecule. Cell preparations enriched in B lymphocytes yielded prominent 43,000 Mr Fc gamma receptors. Thus human monocytes, B lymphocytes, and non-B lymphocytes each appear to have structurally distinct and unique Fc gamma receptors.

Chemical Phenomena↗
PubMed1983

Absence of pH effect on creatine kinase leakage from mouse skeletal muscle.

Skeletal muscle enzyme leakage has been found to be independent of extracellular pH (6.6 - 8.2), changes in ionic strength, osmolarity, and the weight changes that occur during in vitro incubation. This is in contrast to the effect of pH and ionic strength on heart, and no change in heart weight, during incubation in similar media. These observations further emphasize the disparate responses of heart and skeletal muscle to changes in the extracellular environment.

Animals↗