O2 uptake kinetics after acetazolamide administration during moderate- and heavy-intensity exercise

Inhibition of carbonic anhydrase (CA) is associated with a lower plasma lactate concentration ([La-]pl) during fatiguing exercise. We hypothesized that a lower [La-]pl may be associated with faster O2 uptake (V(O2)) kinetics during constant-load exercise. Seven men performed cycle ergometer exercise during control (Con) and acute CA inhibition with acetazolamide (Acz, 10 mg/kg body wt iv). On 6 separate days, each subject performed 6-min step transitions in work rate from 0 to 100 W (below ventilatory threshold, VE(T). Gas exchange was measured breath by breath. Trials were interpolated at 1-s intervals and ensemble averaged to yield a single response. The mean response time (MRT, i.e., time to 63% of total exponential increase) for on- and off-transients was determined using a two- (VE(T)). Arterialized venous blood was sampled from a dorsal hand vein and analyzed for [La-]pl. MRT was similar during Con (31.2 +/- 2.6 and 32.7 +/- 1.2 s for on and off, respectively) and Acz (30.9 +/- 3.0 and 31.4 +/- 1.5 s for on and off, respectively) for work rates VE(T), MRT was similar between Con (69.1 +/- 6.1 and 50.4 +/- 3.5 s for on and off, respectively) and Acz (69.7 +/- 5.9 and 53.8 +/- 3.8 s for on and off, respectively). On- and off-MRTs were slower for >VE(T) than for VE(T) exercise but was lower at the end of the transition during Acz (1.4 +/- 0.2 and 7.1 +/- 0.5 mmol/l for VE(T) respectively) than during Con (2.0 +/- 0.2 and 9.8 +/- 0.9 mmol/l for VE(T), respectively). CA inhibition does not affect O2 utilization at the onset of VE(T) exercise, suggesting that the contribution of oxidative phosphorylation to the energy demand is not affected by acute CA inhibition with Acz.     

SAPALDIA: methods and participation in the cross-sectional part of the Swiss Study on Air Pollution and Lung Diseases in Adults

SAPALDIA--the Swiss Study on Air Pollution and Lung Diseases in Adults--focuses on the long term health effects of low to moderate levels of air pollutants as typically seen in different parts of Switzerland. The aim of the SAPALDIA cross-sectional study carried out in 1991 was to determine the prevalence of bronchial asthma, chronic bronchitis and allergic conditions in the adult population of Switzerland and to identify and to determine the respective importance of potentially influencing factors. These could be both personal (smoking habits, allergy status, family history, occupation) and environmental (outdoor and indoor pollution, aeroallergens, climate). A further aim of the cross-sectional study consisted in the identification of individuals susceptible to present symptoms during a two year observation period and to be included in the SAPALDIA follow-up study. This technical report represents the methodological documentation for the cross-sectional study of SAPALDIA. The instruments and the methods of standardisation are presented and discussed. The medical examination consisted of a computerised interview using a standardised questionnaire, the taking of a blood sample for serological tests, allergy skin testing, the measurement of end expiratory CO and body height, and pulmonary function testing followed by methacholine challenge testing or bronchodilatation testing. The pattern of participation and the 9651 participants of the study, representing 59.3% of the sample, are described. Based on information on non-participants gained by telephone interviews and mailed short questionnaires, possible selection biases are quantified and discussed.     

Calcium and vitamin D status of pregnant teenagers in Maiduguri, Nigeria

This study investigates parameters related to calcium and bone metabolism by determining the concentrations of total calcium, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, parathyroid hormone, and phosphorous in young pregnant women. The patient population was 30 pregnant Nigerian teenage women grouped by trimester (10 per group), 10 women immediately following delivery, and 21 healthy age-matched controls. On the basis of serum prealbumin levels, the general nutrition of the pregnant women was found to be significantly below that of the more privileged and better-educated nonpregnant controls. The mean total calcium concentration in sera of the third-trimester women was 8.83 mg/dL, which was significantly below that of the controls (9.77 mg/dL) and the first-trimester group (9.30 mg/dL). Despite the 10% to 15% decline in the serum level of total calcium during pregnancy, the parathyroid hormone level decreased markedly from 0.60 to 0.61 ng/mL in the first and second trimesters to 0.41 ng/mL in the third trimester. Serum vitamin D and 1,25-dihydroxyvitamin D levels in the second and third trimesters were within the normal range. These data indicate that toward the end of gestation, pregnant teenagers in northern Nigeria appear to become calcium deficient and do not exhibit the expected increase in serum parathyroid hormone levels normally seen in pregnant women.     

Membrane lipids of Rhodopseudomonas viridis

In search of the precyanobacterial origin of the typical thylakoid lipids found in cyanobacteria and chloroplasts, we analyzed the polar lipids of the anaerobic phototrophic bacterium Rhodopseudomonas viridis. Glycolipids (monogalactosyl-, digalactosyl- and glucuronosyl diacylglycerol), phospholipids (phosphatidyl choline, -ethanolamine, -glycerol and cardiolipin) and an ornithine lipid were isolated and identified by NMR (1H, 13C, 31P) and mass spectrometry. Positional distribution and pairing of fatty acids in molecular species show small, but significant differences between glyco- and phospholipids. In this context, a new enzymatic method is described for assigning the enantiomeric structure of the diacylglycerol moiety in glyco- and phospholipids. 14C-Labelling studies suggest that monogalactosyl diacylglycerol is formed by galactosylation of diacylglycerol as in chloroplasts and not by glucosylation followed by epimerization as in cyanobacteria. The two 1,6-linked galactopyranose residues of digalactosyl diacylglycerol are both in beta-linkage and thus differ from the corresponding chloroplast lipid with its alpha-beta-sequence. R. viridis does not contain the sulfolipid, and even phosphate starvation does not induce the synthesis of this most characteristic thylakoid lipid, which on the other hand is present in other anaerobic phototrophic bacteria.