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Biomedical subjects

J Collins

Publications and source records attributed to J Collins.

At least 379 records · Page 21Linked to original sources
PubMed1983

Burkitt's lymphoma presenting with gastroduodenal involvement. Endoscopic description and review of the literature.

A 16-yr-old man with Burkitt's lymphoma presented with 1 mo of epigastric pain and was found at endoscopy to have gastric ulcers with nodular borders and a duodenal mass lesion. Laparotomy revealed a large pelvic mass and tumor involvement of the stomach, small bowel, and retroperitoneal lymph nodes. Presentation with gastroduodenal disease is unusual, and the endoscopic features of Burkitt's lymphoma have not been previously reported. Gastrointestinal involvement with Burkitt's lymphoma is reviewed, and characteristics of the North American and African varieties are contrasted.

Adolescent↗
PubMed1982

Specific binding of [3H]L-glutamate to cerebellar membranes: evidence for recognition site heterogeneity.

The kinetics of interaction of excitatory amino acid analogues and reputed antagonists with a specific binding site for [3H]L-glutamate, having a Kd of 600 nM, were examined in washed cerebellar membranes incubated at 37 degrees C. Displacement curves were analyzed by an iterative computer program for a non-cooperative two-site competitive inhibition model. L-Glutamate, D-glutamate and D-aspartate exhibited simple, mass action kinetics with Hill coefficients near unity and Kis of 1.1, 9.3 and 23.3 microM, respectively. Quisqualate, ibotenate and cyclopentylglutamate had Hill coefficients less than 0.85 and bound to an high affinity component with KHS of 0.4, 0.8 and 1.7 microM, respectively. Neither N-methyl-D-aspartate nor derivatives of kainate, with the exception of a-keto kainate, had KiS less than 0.1 mM. Linear analogues of glutamate with reputed antagonistic properties all exhibited shallow displacement curves with Hill coefficients less than 0.6 and KHS varying from 0.5 to 6.6 microM. Notably, 2-amino-6-phosphonocaproic acid had negligible affinity for the site in contrast to the valeric and pimelic phosphono analogues. The results indicate that [3H]L-glutamate labels a single class of sites that can be resolved into subpopulations by agonists and antagonists and provide additional evidence of excitatory amino acid receptor heterogeneity.

Amino Acids↗
PubMed1982

Inducibility of human beta-interferon gene in mouse L-cell clones.

Transfer of a 36-kilobase piece of human DNA containing the beta-interferon (IFN-beta) gene into mouse Ltk-cells leads to transient expression of human interferon even without an exogenous inducer. A low level of human interferon expression is also found in most stable clones containing the transferred DNA. With double-stranded RNA or Newcastle disease virus (NDV) as inducer, human interferon expression is greatly increased. The induced transcript is identical to normal human IFN-beta mRNA. Neighbouring genes contained on the transferred DNA are co-induced but are not essential for the production of human interferon in mouse L cells.

Clone Cells↗
PubMed1982

Cloning of the complete human cytomegalovirus genome in cosmids.

Purified virion DNA (155 X 10(6) Mr) of human cytomegalovirus (CMV) strain Ad169 was partially cleaved with restriction endonucleases HindIII and EcoRI and cloned in the respective cleavage sites of cosmid pHC79. A complete gene library was established in a set of clones containing the viral DNA in long overlapping segments. Restriction maps for HindIII (29 fragments) and EcoRI (36 fragments) were constructed from the linkage of cosmid-cloned fragments, from double digestions of cloned DNA, and from blot hybridization of labeled cloned viral DNA with restriction fragments of virion DNA and singly or doubly cleaved cosmid clones.

Cloning, Molecular↗
PubMed1981

Monoclonal antibodies against human fibroblast interferon.

A stable hybridoma clone derived by infusion of mouse myeloma cells (cell line Fo) and spleen cells of immunized mice has been isolated which secretes monoclonal antibodies against human fibroblast interferon (interferon-beta). The antibody inhibits the antiviral activity of human fibroblast interferon in an antiviral assay using human FS4 fibroblast, reacts immunologically with interferon-beta separated by sodium dodecylsulfate/polyacrylamide gel electrophoresis and subsequent transfer to nitrocellulose and absorbs interferon-beta immunologically when bound to CNBr-activated Sepharose. It also inhibits the antiviral activity of human fibroblast interferon-beta from which the sugar moiety has been cleaved off by enzymatic treatment. The antibody is therefore probably directed against the protein moiety of the interferon molecules.

Animals↗
PubMed1981

N-Methyl-D-aspartate acid: a convulsant with weak neurotoxic properties.

N-Methyl-D-aspartic acid (NMDA) is 100-fold less potent as a neurotoxin than kainic acid when injected into the rat striatum. However, NMDA, when injected into the hippocampus, causes a more severe seizure disorder than kainic acid and doses of NMDA than produce much smaller lesions than those caused by kainate. These results indicate a poor correlation between convulsant and neurotoxic properties of acidic excitatory amino acids.

Animals↗
PubMed1981

The structure of a thirty-six kilobase region of the human chromosome including the fibroblast interferon gene IFN-beta.

The isolation of a human genomic cosmid hybrid containing the interferon beta gene has recently been reported (Gross et al., 1981). This hybrid was mapped using single and double digests and cross-hybridisation with the sub-cloned EcoRI and BgIII fragments. Purified fragments and subclones were used as hybridisation probes against chromosomal "Southern" blots to show that at least half of the region has been cloned without alteration. This cannot at present be confirmed for the rest of the region due to the presence of highly repetitive DNA on these cloned fragments. Sequencing data on the 5'-end of the fibroblast IFN-beta gene shows a high density of direct and inverted repeats. The IFN-beta mRNA coding region contains no intron, although the possibility of other transcription starts is not ruled out. The cloned region shows no similarities to known genomic clones containing IFN-alpha genes.

Base Sequence↗
PubMed1981

Natural history of electrical interventricular septal force in the course of left ventricular hypertrophy in man.

Initial electrical forces emanating from interventricular septal depolarization, being directed to the right and anteriorly, normally produce an initial negative deflection or Q wave in leads I, aVL and V6 and an initial positive deflection or R wave in leads V1 and V2. The observations of hypertrophied interventricular septum, an integral part of the left ventricle, in patients with left ventricular hypertrophy would predict an increase in these septal electrical forces similar to the total left ventricular (QRS) forces in these subjects. Contrary to this expectation, several studies document an actual decrease or absence of the normally oriented initial forces in ECGs of patients with the criteria of left ventricular hypertrophy. In order to clarify the nature of this paradox, this study was initiated. Our observations suggest that the normal initial septal forces indeed increase as expected, during the initial four to six years, and subsequently show a progressive decline in patients with left ventricular hypertrophy. Although the precise mechanism for the bimodal change in the septal forces during the period of the constancy of the total QRS forces is not clear, a hypothesis based on the current knowledge is advanced to explain these observations.

Adult↗