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Biomedical subjects

G Blundell

Publications and source records attributed to G Blundell.

36 records · Page 2Linked to original sources
PubMed1981

The short metyrapone test: comparison of the plasma ACTH response to metyrapone with the cortisol response to insulin-induced hypoglycaemia in patients with pituitary disease.

After a single dose of 2 g metyrapone given with a snack at 2300 h, blood was taken for estimation of plasma adrenocorticotrophin hormone (ACTH) concentrations at 0800 h the next morning from normal individuals and from patients with pituitary disease. Plasma ACTH concentrations following metyrapone were significantly lower in patients with pituitary disease with no evidence of anterior pituitary hormone deficiency (mean 90.0 +/- SD 63.9 ng/l) when compared with normal individuals (mean 182.5 +/- SD 14.1 ng/l, P leads than 0.01) but significantly greater than in patients with pituitary disease in whom a deficiency of one or more anterior pituitary hormones was demonstrated (mean 50.8 +/- SD 14.1 ng/l, P less than 0.01). It is concluded that the short metyrapone test is a sensitive method of detecting minor degrees of impairment of the negative feedback control of aCTH secretion that would be unrecognized by conventional assessment by insulin-induced hypoglycaemia. The clinical relevance of impaired ACTH release in response to a single dose of metyrapone in patients with pituitary tumours, in whom pituitary function is otherwise shown to be adequate, needs to be determined.

Adrenocorticotropic Hormone↗
PubMed1979

Lung distensibility and airway function in intermediate alpha 1-antitrypsin deficiency (Pi MZ).

We examined the role of intermediate alpha 1-antitrypsin deficiency in predisposing to abnormalities of lung distensibility and airway function in 20 heterozygotes (Pi MZ) who were individually matched with a control Pi M subject of similar age, height, and smoking habits drawn from the same male, working population. There were no significant differences between the heterozygotes and their controls in the results of spirometry, maximum expiratory flow-volume curves (breathing air), single breath nitrogen test, arterialised capillary blood oxygen pressure, or single breath carbon monoxide transfer. Additional studies were made in 12 of the pairs of Pi MZ and Pi M subjects. Comparison of maximum expiratory flow-volume curves breathing air and 80% helium-20% oxygen showed no differences between the Pi MZ and Pi M subjects. Although airway function was similar in the two groups, four of 12 Pi MZ subjects showed abnormalities of the pressure-volume curve of the lung (reduction in lung recoil pressure, abnormal shape factor, increase in functional residual capacity). Abnormalities of washout of a helium-sulphur hexafluoride gas mixture, of a type previously described as characteristic of emphysema, were found in two of the men with abnormal pressure-volume curves. The results suggest that Pi MZ subjects have an increased susceptibility to alveolar abnormalities without increased abnormalities of airway function; this may explain the increased frequency of emphysema at necropsy despite many studies showing no predisposition to abnormal airway function in life. The functional changes we observed would be unlikely to cause symptoms. The risk of disablement from chronic lung disease appears to be only slightly enhanced by intermediate alpha 1-antitrypsin deficiency.

Adult↗
PubMed1976

Relation of alpha-1-antitrypsin phenotype to the performance of pulmonary function tests and to the prevalence of respiratory illness in a working population.

Individuals with severe alpha-1-antitrypsin (alpha1AT) deficiency (phenotype Pi ZZ) are abnormally liable to develop emphysema, but it is uncertain whether those with partial alpha1AT deficiency (phenotypes Pi MS and MZ) are similarly susceptible. This study was undertaken to determine the frequency of the various Pi phenotypes in a working population in Northern Ireland and to compare the performance of simple pulmonary function tests and prevalence of respiratory symptoms and chest illness between different phenotypes. The population sample consisted of 1995 working men and women aged between 35 and 70 years. The MRC Questionnaire (1966) was used to assess respiratory symptoms, a forced expiratory spirogram was recorded, and a blood sample was analysed for alpha1AT phenotype by acid starch gel electrophoresis and antigen-antibody crossed electrophoresis in every case. The percentage frequencies of the alpha1AT phenotypes were: Pi MM 86-5; MS 7-97; MZ 3-86; IM 0-6; FM 0-4; SZ 0-25; M 0-15; SS 0-1; Z 0-05; MP 0-05; FS 0-05. Respiratory symptoms and a history of previous chest illness occurred with similar frequency among the Pi M, MS, and MZ phenotypes, and a comparison of the regression coefficients for FEV1, FVC, and MMF on age for each phenotype group showed no significant differences between them overall, or when subdivided according to smoking habits or dust exposure. These findings provide no evidence that individuals of phenotype Pi MS or MZ are more than usually liable to develop chronic airways obstruction.

Adult↗
PubMed1975

Alpha1 antitrypsin phenotypes in Northern Ireland.

Serum alpha1 antitrypsin levels and phenotypes were examined in 1000 healthy adults in Northern Ireland. The Pi phenotype M accounted for 87-8% Pi MS for 7-3% and Pi MZ for 3-5%. The percentages of the rarer phenotypes were Pi FM 0-3, Pi IM 0-6, Pi SZ 0-4 and Pi Z--0-1. The range of alpha1 antitrypsin levels in different phenotypes showed considerable overlap. Pi MS, Pi MZ and Pi SZ sera gave mean levels of 81%, 61% and 40% respectively of the mean level obtained in Pi M sera and that of the Pi Z--minus serum, 5%. Two distinct types of anomalous pattern were encountered in sera from ten subjects.

Adult↗
PubMed1974

Haemoglobin Belfast 15 (A12) tryptophan leading to arginine: a new unstable haemoglobin variant.

A new unstable haemoglobin, alpha(2)beta(2)15 Trp--> Arg (Hb Belfast), with increased oxygen affinity has been found during the routine investigation of a long-stay psychiatric patient. It seemed to cause little haematological disorder. The reticulocytes synthesized normal and abnormal beta-chains at the same rate but in the circulating blood Hb Belfast amounted to only 27.5% of the total haemoglobin.

Adult↗