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Biomedical subjects

G M Cooper

Publications and source records attributed to G M Cooper.

At least 127 records · Page 7Linked to original sources
PubMed1985

A retroviral myc gene induces preneoplastic transformation of lymphocytes in a bursal transplantation assay.

Treatment of chicken embryos with cyclophosphamide results in ablation of bursal lymphocytes. Bursal follicles can be reconstructed by infusion of embryonic bursal cells. Histologic examination of reconstituting bursal follicles showed that the first lymphocytes to appear were large pyrinophilic lymphoblasts that lined up adjacent to the bursal basement membrane and appeared to serve as progenitors for the differentiation of bursal medullary lymphocytes. When these cells were infected with the avian myelocytomatosis virus HB1 bearing a v-myc oncogene they appeared to home to the region of the bursal basement membrane but failed to differentiate. Instead, they formed structures indistinguishable from the preneoplastic transformed follicles that develop during bursal lymphomagenesis induced by lymphoid leukosis viruses. The DNA from these transformed follicles contained the HB1 v-myc gene but lacked the ability to transform NIH/3T3 mouse cells. Therefore these preneoplastic lesions were induced directly by HB1 myc and did not require the expression of Blym-1 or similar oncogenes. Exploitation of this transplantation technique with the chicken bursa will provide a useful method for assessing the stage-specific activity of oncogenes in vivo.

Animals↗
PubMed1985

Auscultatory measurement of arterial pressure during anaesthesia: a reassessment of Korotkoff sounds.

The accuracy of the indirect auscultatory method, using Korotkoff sounds for determination of arterial pressures, was investigated by comparison with direct intra-arterial measurements. Eight hundred and sixty-three comparisons were made in 25 patients aged between 27 and 75 years over blood pressures ranging from 59 to 235 mmHg for systolic and 28 to 145 mmHg for diastolic. The regression equation for all systolic pressure measurements was y = 13.9 + 0.81x, and for all diastolic pressure measurements was y = 21.4 + 0.71x. Although there was a significant (P less than 0.001) correlation coefficient between direct and indirect measurements for both systolic (r = 0.93) and diastolic pressures (r = 0.79), the 95% confidence limits (+/- 22 mmHg for systolic and +/- 19 mmHg for diastolic) were very wide, reflecting the influences of observer variation and other sources of error.

Adult↗
PubMed1985

Recovery from day-case anaesthesia. The effect of different inhalational anaesthetic agents.

Sixty unpremedicated patients undergoing dilatation and curettage were allocated randomly to receive one of three inhalational agents (halothane, enflurane or isoflurane) to supplement 67% nitrous oxide in oxygen after induction of anaesthesia with methohexitone. Recovery was assessed by the time patients took to open their eyes, to give their correct date of birth, to regain their pre-operative level of manipulative skill with a children's postbox toy, and by comparing pre-operative and postoperative performance of a paper and pencil test (the p-deletion test). There was no difference in the time to open eyes or to regain their pre-operative score with the postbox whether the patients received halothane, enflurane or isoflurane. Patients in the isoflurane group took longer than patients in the enflurane group to give their correct date of birth, but they performed better in the p-deletion test postoperatively, completing more lines with the same number of errors. Patients receiving enflurane committed more errors postoperatively in the p-deletion test. The incidence of complications was low and was not influenced by the choice of inhalational agent.

Adult↗
PubMed1984

Nucleotide sequence of a human Blym transforming gene activated in a Burkitt's lymphoma.

The nucleotide sequence of a human Blym-1 transforming gene activated in a Burkitt's lymphoma cell line was determined. This sequence predicts a small protein of 58 amino acids that is 33 percent identical to the predicted product of chicken Blym-1, the activated transforming gene of chicken B cell lymphomas. Both the human and chicken Blym-1 genes exhibit significant identity to an amino-terminal region of transferrins.

Amino Acid Sequence↗
PubMed1984

Somatic activation of rasK gene in a human ovarian carcinoma.

A tumor isolate from a patient with serous cystadenocarcinoma of the ovary contained an activated rasK gene detected hy transfection of NIH/3T3 cells. In contrast, DNA from normal cells of the same patient lacked transforming activity, indicating that activation of this transforming gene was the consequence of somatic mutation in the neoplastic cells. The transforming gene product displayed an electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels that differed from the mobilities of rasK transforming proteins in other tumors, indicating that a previously undescribed mutation was responsible for activation of rasK in this ovarian carcinoma.

Animals↗
PubMed1984

Mapping of the human Blym-1 transforming gene activated in Burkitt lymphomas to chromosome 1.

Blym-1, a transforming gene detected by transfection of NIH 3T3 cells with DNA from Burkitt lymphomas, was mapped to the short arm of chromosome 1 (1p32) by chromosomal in situ hybridization. The Blym-1 gene was not physically linked to the cellular myc oncogene or to any of the immunoglobulin gene loci implicated in the characteristic chromosomal translocations in Burkitt lymphoma.

Base Sequence↗
PubMed1984

Detection of a molecular complex between ras proteins and transferrin receptor.

Immunoprecipitation of extracts of human carcinoma cell lines with three different monoclonal antibodies generated against ras proteins revealed the coprecipitation of a 90,000 dalton protein. The coprecipitated protein was identified as the transferrin receptor by comigration in both reducing and nonreducing SDS-polyacrylamide gels, by absorption with a monoclonal antibody directed against transferrin receptor, and by analysis of partial proteolysis products. Coprecipitation of the transferrin receptor with three monoclonal antibodies with differing specificities to ras proteins, as well as the inability to coprecipitate the transferrin receptor from cell extracts from which ras proteins were depleted by preabsorption, indicates that ras proteins and the transferrin receptor form a molecular complex. This complex is disrupted by addition of transferrin to cell extracts. These findings suggest that ras proteins function in regulation of cell growth via interaction with the cell surface receptor for transferrin.

Antibodies, Monoclonal↗
PubMed1984

Activation of ras genes in human tumors does not affect localization, modification, or nucleotide binding properties of p21.

A comparison of proteins encoded by normal human ras genes and by mutant rasH or rasK genes activated in human carcinomas revealed no changes in subcellular localization, posttranslational modification, or guanine nucleotide binding associated with activation. Subcellular fractionation indicated that both normal and activated ras proteins were associated exclusively with the membrane fraction. Furthermore, both normal and activated ras proteins exhibited similar degrees of posttranslational acylation. The KD for dGTP binding was 1.0-2.2 X 10(-8) M, with no consistent differences between normal and activated ras proteins. In addition, a survey of 13 possible competing nucleotides revealed no differences in the specificity of nucleotide binding associated with ras gene activation. These results indicate that structural mutations which activate ras gene transforming activity do not alter the protein's known biochemical parameters and in particular do not affect the protein's intrinsic ability to bind guanine nucleotides.

Cell Line↗
PubMed1984

The 1984 Walter Hubert lecture. Activation of transforming genes in neoplasms.

Cellular oncogenes have been identified by the biological activity of tumour DNAs in transfection assays and/or by homology to the transforming genes of retroviruses. In some tumours, the biological activity, organization or expression of these genes is altered, suggesting that such alterations contribute to the development of neoplastic disease. Experiments leading to the identification of cellular oncogenes are reviewed and our current understanding of the mechanisms by which they induce transformation of cells in culture and may contribute to the pathogenesis of neoplasms in vivo is discussed.

Animals↗
PubMed1984

Plasma concentrations of catecholamines following adrenaline infiltration during gynaecological surgery.

High pressure liquid chromatography with electrochemical detection has been used to measure plasma catecholamine concentrations in six gynaecological patients undergoing halothane anaesthesia for cervical cone biopsy. Mean catecholamine concentrations before infiltration were 1.01 +/- 0.23 (SEM) nmol litre-1 (185 +/- 43 pg ml-1) for adrenaline, and 2.2 +/- 0.25 nmol litre-1 (364 +/- 41 (185 +/- 43 pg ml-1) for adrenaline, and 2.2 +/- 0.25 nmol litre-1 (364 +/- 41 pg ml-1) for noradrenaline. Following infiltration with 0.5% bupivacaine 15 ml with adrenaline 1:200 000, plasma adrenaline concentrations increased to a mean peak concentration of 18.6 +/- 3.7 nmol litre-1 (3.4 +/- 0.69 ng litre-1). The lack of sympathoneuronal response was confirmed by simultaneous measurements of plasma noradrenaline concentrations, which did not change significantly. The proportion of the injected adrenaline measured in the intravascular compartment was 21.8%. The significance of intravascular absorption of exogenous adrenaline is discussed in relation to the use of halothane anaesthesia and the concurrent injection of a local anaesthetic solution.

Absorption↗
PubMed1984

The validity of informed consent in a clinical study.

Patients, aged 36 to 78 years, who had participated in two studies that included the ventilatory effects of postoperative analgesia, returned a questionnaire canvassing their views of the procedure for obtaining consent and the conduct of the study. Fourteen of 18 patients from one study, and all 18 from the second, returned their questionnaires. Thirty of the 32 patients were satisfied with the pre-operative explanation. Eleven patients felt obliged to take part, not because of coercion, but from a sense of duty to others. The breathing tests caused discomfort to eight patients but only one of them found this more than expected from the pre-operative explanation. Only two patients, both in the second study, said that they would not volunteer again for a similar study. There was no suggestion that the age of the patient or the fact that they were undergoing major surgery had any influence on their attitudes or comprehension. It may be prudent to use this type of questionnaire to evaluate the response of patients to some research projects.

Aged↗
PubMed1984

Ventilatory effects of pre- and postoperative diamorphine. A comparison of extradural with intramuscular administration.

Twenty-two patients were studied before and after major abdominal vascular surgery to determine the effect on ventilation of 5 mg diamorphine given either extradurally or intramuscularly. Diamorphine depressed ventilation maximally at 30 minutes when given by either route. Before operation resting ventilation was reduced by 33% after extradural and 17% after intramuscular diamorphine; PaCO2 increased by an average of 0.5 kPa (either route); ventilation at 7.3 kPa PaCO2 was reduced 40% after extradural and 33% after intramuscular diamorphine. After operation the effect of diamorphine on ventilation was qualitatively similar but resting baseline ventilation was increased from 9.4 to 10.9 litres/minute. The highest individual PaCO2 values were found during the pre-operative study: 6.5 kPa after extradural diamorphine, 6.4 kPa after intramuscular diamorphine. Pain relief was unsatisfactory after intramuscular diamorphine. Four out of six patients requested further analgesia by 3 hours after administration. No patient who received extradural diamorphine required further analgesia for at least 6 hours.

Adult↗
PubMed1984

Transformation of NIH 3T3 cells by DNA of the MCF-7 human mammary carcinoma cell line induces expression of an endogenous murine leukemia provirus.

Previous studies identified two glycoproteins of 86 (gp86) and 72 (gp72) kilodaltons and two nonglycosylated proteins of 70 (p70) and 19 (p19) kilodaltons which were specifically expressed in NIH cells transformed by DNA of the MCF-7 human mammary carcinoma cell line. Pulse-chase experiments and the use of tunicamycin to inhibit glycosylation suggested that gp86, gp72, and p19 were related as precursor products. Characteristics of the four transformation-associated proteins resembled those of murine leukemia virus (MuLV) proteins. Sera raised against disrupted MuLV immunoprecipitated the same four proteins in extracts of NIH(MCF-7) cells and MuLV-infected NIH 3T3 cells. In addition, a monoclonal antibody against MuLV gp70 immunoprecipitated proteins gp86 and gp72, whereas a monoclonal antibody against MuLV p15(E) immunoprecipitated gp86 and p19. These results indicate that proteins gp86, gp72, and p19 expressed in NIH(MCF-7) transformants correspond to MuLV envelope proteins gp80env, gp70, and p15(E), respectively. The transformation-associated protein p70 appears to be a non-envelope MuLV protein, most likely p65gag. Northern blot analysis confirmed that transformation of NIH cells by MCF-7 mammary carcinoma DNA led to the induction of an endogenous MuLV provirus.

Animals↗
PubMed1983

Molecular cloning and nucleotide sequence of a transforming gene detected by transfection of chicken B-cell lymphoma DNA.

A transforming gene detected by transfection of chicken B-cell lymphoma DNA has been isolated by molecular cloning. It is homologous to a conserved family of sequences present in normal chicken and human DNAs but is not related to transforming genes of acutely transforming retroviruses. The nucleotide sequence of the cloned transforming gene suggests that it encodes a protein that is partially homologous to the amino terminus of transferrin and related proteins although only about one tenth the size of transferrin.

Animals↗