An artificial bifunctional enzyme, γ-glutamyl kinase/γ-glutamyl phosphate reductase, improves NaCl tolerance when expressed in Escherichia coli

Summary An artificial bifunctional enzyme, -glutamyl kinase/-glutamyl phosphate reductase, was obtained by fusing the Escherichia coli genes proA and proB. The proB gene was fused to the 5-end of the proA gene with a linker encoding five amino acids. When expressed in E. coli enhanced intracellular concentrations of proline were observed. At 0.6 M NaCl the growth rates for the strain carrying the fusion enzyme and a control harbouring a plasmid encoding the wild-type enzymes were 320 and 530 min, respectively.     

Eicosanoid balance and perfusion redistribution of oleic acid-induced acute lung injury.

We have proposed that endogenous prostacyclin opposes the vasoconstriction responsible for redistribution of regional pulmonary blood flow (rPBF) away from areas of increased regional lung water concentration (rLWC) in canine oleic acid- (OA) induced acute lung injury (D. P. Schuster and J. Haller. J. Appl. Physiol. 69: 353-361, 1990). To test this hypothesis, we related regional lung tissue concentrations of 6-ketoprostaglandin (PG) F1 alpha and thromboxane (Tx) B2 in tissue samples obtained 2.5 h after administration of OA (0.08 ml/kg iv) to rPBF and rLWC measured by positron emission tomography. After OA only (n = 16), rLWC increased in dependent lung regions. Some animals responded to increased rLWC by redistribution of rPBF away from the most edematous regions (OA-R, n = 6), whereas others did not (OA-NR, n = 10). In another six animals, meclofenamate was administered after OA (OA-meclo). After OA, tissue concentrations of 6-keto-PGF1 alpha were greater than TxB2 in all groups, but concentrations of 6-keto-PGF1 alpha were not different between OA-R and OA-NR animals. TxB2 was increased in the dependent regions of animals in both OA-R and OA-NR groups compared with controls (no OA, n = 4, P < 0.05). The tissue TxB2/6-keto-PGF1 alpha ratio was smaller in controls and OA-NR in which no perfusion redistribution occurred than in OA-R and OA-meclo in which it did occur. This TxB2/6-keto-PGF1 alpha ratio correlated significantly with the magnitude of perfusion redistribution.(ABSTRACT TRUNCATED AT 250 WORDS)     

Glomerular anionic charge in congenital nephrotic syndrome of the Finnish type

Summary Decrease of the anionic charge of the glomerular basement membrane and especially the reduced amount of heparan sulphate proteoglycan in the lamina rara externa has been suggested to be the basic pathogenetic defect in congenital nephrotic syndrome. In the present study the anionic charge of glomeruli was examined in the congenital nephrotic syndrome of the Finnish type and in controls using cationic stains (polyethyleneimine, Ruthenium Red) in electron microscopy. Chondroitinase and heparinase treatments were used to characterize further the anionic elements detected. Scanning electron microscopy (SEM) was used in addition to transmission electron microscopy (TEM) to examine the tridimensional structure and secondary changes of podocytes in this syndrome. The number (mean ± SD) of polyethyleneimine granules per 1 μm length of lamina rara externa of the glomerular basement membrane was 24.9 ± 4.5 in control and 2.32 ± 4.3 in congenital nephrotic syndrome subjects. The Ruthenium Red staining pattern was closely similar in syndrome and control kidneys. The granules evident after staining with either cationic stain were seen after chondroitinase but not after heparinase treatment in control as well as in syndrome patient kidney samples. No denuded areas of basement membrane in 42 glomeruli from four syndrome patients were found in SEM. In conclusion, the amount of anionic sites in the lamina rara externa as detected by either cationic stain was comparable to controls. These results do not support the hypothesis of decreased anionic sites in the lamina rara externa of the glomerular basement membrane in congenital nephrotic syndrome of the Finnish type.     

Fine mapping and haplotype analysis of the locus for congenital nephrotic syndrome on chromosome 19q13.1.

We have recently localized the gene for congenital nephrotic syndrome of the Finnish type (CNF) to chromosome 19q12-13.1. On the basis of observed recombination events, the gene was localized between markers D19S416/D19S425/D19S213/D19S208/D19S191 and D19S224. Here we have extended the mapping efforts, on the basis of a detailed physical map of the region. By means of three new polymorphic markers--D19S608, D19S609, and D19S610--developed in this study, the critical candidate region could be further restricted. Significant linkage disequilibrium was observed with markers D19S610, D19S608, D19S224, and D19S220, the strongest allelic association being 84% with marker D19S610 at 19q13.1. This suggests that the CNF gene locus lies in close proximity to marker D19S610. Combination of the informative markers revealed four main haplotype categories. Different geographic distribution was observed between these haplotype groups when they were placed on the map of finland according to the birthplaces of grandparents.     

Exposure to a combination of heat and hyperoxia during cycling at submaximal intensity does not alter thermoregulatory responses

In this study, we tested the hypothesis that breathing hyperoxic air (F_inO₂ = 0.40) while exercising in a hot environment exerts negative effects on the total tissue level of haemoglobin concentration (tHb); core (T_core) and skin (T_skin) temperatures; muscle activity; heart rate; blood concentration of lactate; pH; partial pressure of oxygen (P_aO₂) and carbon dioxide; arterial oxygen saturation (S_aO₂); and perceptual responses. Ten well-trained male athletes cycled at submaximal intensity at 21°C or 33°C in randomized order: first for 20 min while breathing normal air (F_inO₂ = 0.21) and then 10 min with F_inO₂ = 0.40 (HOX). At both temperatures, S_aO₂ and P_aO₂, but not tHb, were increased by HOX. Tskin and perception of exertion and thermal discomfort were higher at 33°C than 21°C (p < 0.01), but independent of F_inO₂. T_core and muscle activity were the same under all conditions (p > 0.07). Blood lactate and heart rate were higher at 33°C than 21°C. In conclusion, during 30 min of submaximal cycling at 21°C or 33°C, T_core, T_skin and T_body, tHb, muscle activity and ratings of perceived exertion and thermal discomfort were the same under normoxic and hyperoxic conditions. Accordingly, breathing hyperoxic air (F_inO₂ = 0.40) did not affect thermoregulation under these conditions.     

Orthostatic Hypotension and Elevated Resting Heart Rate Predict Low-Energy Fractures in the Population: The Malm? Preventive Project

BackgroundAutonomic disorders of the cardiovascular system, such as orthostatic hypotension and elevated resting heart rate, predict mortality and cardiovascular events in the population. Low-energy-fractures constitute a substantial clinical problem that may represent an additional risk related to such autonomic dysfunction.AimsTo test the association between orthostatic hypotension, resting heart rate and incidence of low-energy-fractures in the general population.ConclusionOrthostatic blood pressure decline and elevated resting heart rate independently predict low-energy fractures in a middle-aged population. These two measures of subclinical cardiovascular dysautonomia may herald increased risks many years in advance, even if symptoms may not be detectable. Although the effect sizes are moderate, the easily accessible clinical parameters of orthostatic blood pressure response and resting heart rate deserve consideration as new risk predictors to yield more accurate decisions on primary prevention of low-energy fractures.     

Hydrolysis and Esterification with Lipase from Candida Cylindracea. Influence of the Reaction Conditions and Acid Moiety on the Enantiomeric Excess

The enantiomeric ratio for hydrolysis and synthesis of 1-phenyl ethanol esters of straight chain aliphatic carboxylic acids catalyzed by Candida cylindracea lipase was determined. A distinct maximum in enantiomeric ratio was observed for valeric and caproic acid in the hydrolytic direction. No significant maximum could be determined in the esterification reaction. Even though the enzyme provided larger enantiomeric ratios in the synthetic direction the enantiomeric excess of the alcohol was not higher. The enantiomeric excess was depressed by racemization reactions in the esterification as the reaction approached thermodynamic equilibrium at an insufficient conversion. While choosing the optimal chain length of the acyl donor is important in hydrolytic reactions it seems to be of greater value to raise the equilibrium conversion in the esterification reactions.