Biomedical subjects
Publications and source records attributed to Thomas M Macdonald.
Laboratory evidence suggests that vitamin A could have a protective effect on respiratory status in patients with cystic fibrosis (CF). This study shows a significant correlation between serum vitamin A concentrations and every aspect of lung function tested in 38 patients with stable CF. Serum vitamin D and vitamin E concentrations were also measured but did not show any significant correlations with lung function.
AIMS: To test the non-inferiority of a single dose of tadalafil 20 mg compared with placebo with respect to 26-h mean ambulatory systolic and diastolic blood pressure in treated and untreated hypertensive subjects. METHODS: A multicentre, randomized, double-blind, placebo-controlled crossover study in 114 subjects with hypertension (36 subjects on no therapy with daytime mean ambulatory blood pressure >/= 140/85 mmHg; 38 subjects on two to four classes of antihypertensive agents with daytime mean ambulatory blood pressure >/=140/85 mmHg and 40 subjects on two to four classes of antihypertensive agents with ambulatory blood pressure < 140/85 mmHg). RESULTS: Overall tadalafil reduced mean ambulatory blood pressure monitor systolic and diastolic blood pressure by 4.8 mmHg [95% confidence interval (Cl) 3.7, 5.9; P < 0.01] and 2.9 mmHg (95% CI 1.9, 3.6; P < 0.01), respectively, compared with placebo. In hypertensive subjects with uncontrolled blood pressure on two to four classes of antihypertensive agents (n = 36) tadalafil reduced mean ABPM systolic and diastolic blood pressure by 7.5 mmHg (95% CI 5.4, 9.6; P < 0.01) and 4.3 mmHg (95% CI 6.1, 8.9; P < 0.01) compared with placebo. CONCLUSIONS: In patients with uncontrolled hypertension on multiple agents the addition of tadalafil 20 mg lowered mean 26-h blood pressure.
The Walker cohort is a database of over 48,000 birth records that has recently become available. It contains meticulously recorded details of pregnancy, labour, birth and care before discharge for babies born in hospital in Dundee, Scotland between 1952 and 1966. These babies accounted for 75% of all births in Dundee at this time. Over 34,000 (73%) of these subjects can be identified and this presents the opportunity to link this birth information with a large number of current health-outcome databases covering both primary and secondary care. Further, it allows linkage of records across siblings and over two and, in future, three generations. The number of birth records available and linkage to current databases make this a unique birth cohort with huge potential for the investigation of the fetal origins of adult disease.
The aldosterone-to-renin ratio (ARR) is a marker of aldosterone activity in hypertension. We examined the relationship of the ARR to the distribution of two biallelic polymorphisms at the CYP11B2 gene locus. One polymorphism affects a putative steroidogenic factor-1 binding site (-344 T/C) in the 5'-regulatory region, whereas the other marker reflects replacement of the intron-2 from CYP11B2 with that from the neighboring gene encoding 11beta-hydroxylase (CYP11B1; wild-type/conversion). We studied consecutive referrals to the Tayside hypertension clinic in 1998. Because the specificity of ARR (pmol/liter/ng/ml/h) for hyperaldosteronism increases with its threshold, ARRs of at least 750 and 1000 were used. A total of 375 patients were assessed; 86.9% had complete data. There were significant excesses of steroidogenic factor-1 (T) (ARR >/= 750, 0.62 vs. 0.51, P = 0.014; ARR >/= 1000, 0.63 vs. 0.51, P = 0.039) and intron-2 (conversion) (ARR >/= 750, 0.49 vs. 0.41, P = 0.205; ARR >/= 1000, 0.54 vs. 0.41, P = 0.029) alleles in patients with a raised ARR. The odds ratio for a raised ARR was 2.27 [95% confidence interval, 1.01, 5.09; P < 0.05] comparing patients with a homozygous haplotype for these alleles with those without any such alleles, and this risk increased with age. This study supports the notion that there is a genetic component that regulates aldosterone production and that hyperaldosteronism might develop over time in susceptible individuals.