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Biomedical subjects

G M Rees

Publications and source records attributed to G M Rees.

At least 55 records · Page 3Linked to original sources
PubMed1980

Ectopic production of methionine enkephalin and beta-endorphin.

Immunoreactive methionine enkephalin and beta-endorphin were sought by serial dilution of tissue extracts and assay of chromatographic fractions in non-endocrine tumour tissue from three patients with the ectopic adrenocorticotrophin syndrome associated with carcinoid tumours and in normal lung tissue and thymic tissue from a patient with myasthenia gravis. In all cases serial dilution of extracts showed parellelism to standard radioimmunoassay curves. The two peptides were found in high concentration in the three tumours but were undetectable in the control tissues. In a single case tested the methionine enkephalin concentration in a vein draining the tumour was twice that in a peripheral vein. In view of their profound effect on behaviour in animals and potent analgesic activity in animals and man the ectopic secretion of methionine enkephalin and beta-endorphin may modify the clinical features of a wide variety of tumours and produce some of the diverse clinical syndromes associated with malignancy.

ACTH Syndrome, Ectopic↗
PubMed1980

10 Years of infective endocarditis at St. Bartholomew's Hospital: analysis of clinical features and treatment in relation to prognosis and mortality.

A retrospective survey of patients with infective endocarditis at St. Bartholomew's Hospital in the decade 1966--75 showed a male/female ratio of 1.5/1. The commonest presenting features were malaise, fever, new cardiac symptoms, heart-failure, splenomegaly, and finger clubbing. The commonest problem during treatment was heart-failure. As in the two previous decades, viridans streptococci were the commonest causative organisms. Acute endocarditis was caused by Staphylococcus aureus. 6 patients' lives were saved by heart-valve replacement during medical treatment. Of 3 patients who relapsed, 1 died. The overall mortality at six months was 20%, compared with 40% in the two previous decades. Of the patients with proven subacute infective endocarditis thought to have received adequate antibiotic treatment, only 5 of 49 (10%) died; in a similar group of patients in the previous decade 19% died. Early surgical intervention probably accounts for the improved prognosis.

Acute Disease↗
PubMed1979

Ebstein's anomaly in association with anomalous nodoventricular conduction. Pre-operative and intra-operative electrophysiological studies.

A 13 year old girl with Ebstein's anomaly was investigated for refractory paroxysmal tachycardias and ventricular pre-excitation. Intracardiac electrophysiological studies demonstrated that ventricular pre-excitation was due to conduction in an anomalous nodo-ventricular pathway. Tachycardia occurred as a result of re-entry within the A-V node with pre-excitation during tachycardia due to conduction in the nodo-ventricular pathway. These tachycardias were controlled initially by medical therapy but because of increasing frequency of attacks, occasionally requiring D.C. conversion, further electrophysiological studies and epicardial mapping were undertaken. The epicardial surface of the right ventricle and right atrium were mapped during tachycardia. The results of the studies confirmed that a direct anomalous atrio-ventricular pathway was not present and that re-entrant tachycardia did not involve an accessory pathway of this type. A rapid atrial pacing system was implanted and paroxysmal tachycardias have been successfully controlled.

Action Potentials↗
PubMed1979

The effect of nitrous oxide on the cell cycle in human bone marrow.

The effect of 24 h exposure to nitrous oxide on the cell division cycle in human bone marrow has been studied in vivo using the technique of DNA flow microfluorimetry. All patients who received nitrous oxide showed a significant increase in the proportion of early S-phase cells with a decrease in late S, G2 and mitotic cells. These changes resemble those seen following the use of S-phase-specific cytotoxic drugs. Control patients showed no such effect. Parallel studies have suggested that interference with the function of vitamin B12 underlies this response. Nitrous oxide may provide a convenient method for studying the cell kinetic aspects of acute B12 deficiency and the possibility of using it to increase the therapeutic index of antitumour drugs is discussed.

Bone Marrow↗
PubMed1978

Megaloblastic haemopoiesis in patients receiving nitrous oxide.

In a prospective study the incidence of megaloblastic change after ventilation with nitrous oxide for periods of up to 24 h has been determined and the cause of the altered D.N.A. synthesis studied with the deoxyuridine (dU) suppression test in 22 patients undergoing cardiac bypass surgery. 8 patients who received nitrous oxide and oxygen for 24 h had megaloblastic bone-marrow aspirates and abnormal dU suppression tests at the end of ventilation. 5 patients who received no nitrous oxide had normoblastic aspirates and normal dU suppression test. Of the remaining 9 patients, who received nitrous oxide during the operation only, 3 had abnormal dU suppression tests at 24 h. The abnormality revealed by the dU suppression tests was identical with that found in vitamin-B12 deficiency, but the patients' serum-B12 concentrations were normal. These results suggest that nitrous oxide interferes with the function of vitamin B12. Nitrous oxide oxidises vitamin B12 in vitro, and probably also in vivo when premixed 50% nitrous oxide and 50% oxygen mixture ('Entonox') is given.

Acute Disease↗
PubMed1977

Lung tumours and ACTH production.

ACTH levels measured by N- and C-terminal immunoassays and cytochemical bioassay, were measured in fourteen lung tumours not associated with the ectopic ACTH syndrome and in macroscopically normal lung tissue taken from the same patients at thoracotomy. Significant concentrations of immunocative (greater than 3 ng/g wet weight) and bioactive (greater than 0.2 ng/g wet weight) ACTH were found in all the carcinoid and oat cell tumours (n=9), a combined tumour (poorly differentiated adenocarcinoma with large cell carcinoid elements), and a poorly differentiated squamous cell tumour. All the carcinoid tumours contained more C- than N-terminal ACTH immunoactivity. The squamous cell tumours (n=2), anaplastic tumours (n=2) and adenocarcinoma contained insignificant ACTH levels. There was a good correlation between the ACTH levels and the presence of secretory granules in the tumours examined ultrastructually. All the macroscopically normal samples of lung tissue contained immuno and bioactive ACTH-like material, the levels of which correlated well with ACTH levels in the tumour tissue. It is suggested that all lung tumours of carcinoid or oat cell type synthesize ACTH-like materials although clinical evidence of the ectopic ACTH syndrome may be absent. The presence of ACTH-like materials in non-tumorous lung tissue in patients with lung cancer may indicate a low level of ACTH production throughout the lung or sequestration of ACTH containing granules secreted by the tumour.

Adenocarcinoma↗
PubMed1971

Surgical treatment of pulmonary metastases from testicular tumours.

Isolated pulmonary metastases from testicular tumours were treated by surgery in nine patients. Six are alive and well with no clinical evidence of recurrence. Three of the survivors were operated on more than 10 years ago. Surgical treatment should be considered in such patients, particularly as the metastases are often solitary and may be better differentiated histologically than the primary tumour. Mortality and morbidity rates after thoracotomy are minimal.

Adult↗