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Biomedical subjects

L Larsson

Publications and source records attributed to L Larsson.

At least 307 records · Page 17Linked to original sources
PubMed1985

Use of gas chromatography to differentiate Mycobacterium leprae from cultivable armadillo-derived mycobacteria, M. avium/intracellulare, and M. lepraemurium by analysis of secondary alcohols.

Two long-chain secondary alcohols, 2-octadecanol and 2-eicosanol, were demonstrated by gas chromatography in hydrolysates of Mycobacterium avium/intracellulare, in cultivable, armadillo-derived mycobacteria, and in M. lepraemurium grown in vivo, but they were not found in purified suspensions of M. leprae isolated from experimentally infected armadillos. Gas chromatographic analysis of these alcohols constitutes a method for rapid detection and quantification of contaminating mycobacteria in preparations of M. leprae intended, for example, for vaccine use. The technique may also be of value for critical evaluation of cultures of "in vitro-grown" M. leprae.

Animals↗
PubMed1985

Effect of propranolol on post-traumatic hypophosphataemia and catecholamine secretion.

Trauma may induce disturbance in the homeostasis and metabolism of phosphate. Serum phosphate decreases rapidly after trauma, and this rapid fall is followed by more slowly progressing hypophosphataemia, reaching minimum values on post-trauma days 2-5. The effect of propranolol on post-traumatic hypophosphataemia was studied in an experimental model, using anaesthetized pigs. Propranolol prevented the initial rapid decrease in serum phosphate. Twelve hours after the trauma, however, both the propranolol-treated and the untreated pigs showed significant serum phosphate depletion, with progression during the 48-hour observation period. The urinary phosphate excretion did not differ between the two groups, and after 48 hours the cumulative loss was the same in both groups. The adrenergic response to trauma was significantly greater in the propranolol-treated than in the untreated group. The results suggested that the rapid serum phosphate fall immediately after trauma was caused by adrenaline release. The second, slower phase was not related to adrenaline or noradrenaline release, but showed correlation with the urinary loss of phosphate.

Animals↗
PubMed1984

A method for quantitative wet chemical analysis of urinary calculi.

We describe a simple method for quantitative chemical analysis of urinary calculi requiring no specialized equipment. Pulverized calculi are dried over silica gel at room temperature and dissolved in nitric acid, which was the only effective agent for complete dissolution. Calcium, magnesium, ammonium, and phosphate are then determined by conventional methods. Oxalate is determined by a method based on the quenching action of oxalate on the fluorescence of a zirconium-flavonol complex. Uric acid, when treated with nitric acid, is stoichiometrically converted to alloxan, which is determined fluorimetrically with 1,2-phenylenediamine. Similarly, cystine is oxidized by nitric acid to sulfate, which is determined turbidimetrically as barium sulfate. Protein is determined spectrophotometrically as xanthoprotein. The total mass recovery of authentic calculi was 92.2 +/- 6.7 (SD) per cent. The method permits analysis of calculi as small as 1.0 mg. Internal quality control is performed with specially designed control samples.

Cations↗
PubMed1984

Studies on crystalluria in calcium oxalate stone formers.

The excretion of calcium oxalate and calcium phosphate crystals was studied in fractionated 24 h urine from 7 men with recurrent calcium oxalate stone disease, both before and during daily administration of 5 mg bendroflumethiazide. Urinary calcium, oxalate, magnesium, citrate, phosphate, pH, and inhibition of calcium oxalate crystal growth rate were analyzed in all samples. Exclusively calcium oxalate crystals were found in 30 per cent of the samples, all with a pH below 6.25, whereas calcium phosphate was the crystal type encountered in urine with a pH above 6.50. Bendroflumethiazide decreased the volume of calcium phosphate but not of calcium oxalate crystals. During the period of observation there was no correlation between calcium oxalate supersaturation and calcium oxalate crystal volume, but a relationship was demonstrated between calcium phosphate supersaturation and calcium phosphate crystal volume.

Adult↗
PubMed1984

Variations in urine composition during the day in patients with calcium oxalate stone disease.

The diurnal variations of urine composition with respect to calcium, magnesium, oxalate, citrate and inhibition of calcium oxalate crystal growth were studied in patients with recurrent calcium oxalate stone disease. There was considerable variation in the excretion of the different urine constituents with meal-related peaks, which was most pronounced for calcium. The highest concentration of calcium was observed before noon, and between 7 and 11 p.m. Oxalate concentration was highest between 6 and 10 a.m. Consequently, the highest levels of supersaturation were recorded between 6 and 10 a.m., and 6 and 10 p.m. The inhibition index was at the highest level during the first morning hours and could be important in counteracting crystal growth at that time. The risk of exceeding a theoretical formation product of calcium oxalate appeared to be low, with a 24-hour urine volume more than 2,000 ml.

Adult↗
PubMed1984

The composition of catheter encrustations, including the effects of allopurinol treatment.

The composition of encrustations precipitated on long-term indwelling urethral catheters was analysed using a newly developed wet chemical method that allows determination of small sample volumes. In contrast to earlier studies, the major portion of the encrusted material could be identified; ammonium magnesium phosphate and calcium phosphates (brushite and apatite) were the major components. The effect of allopurinol was also investigated and it was found to decrease significantly the amounts of urate and calcium phosphate but not to lower significantly the total amount of material precipitated on the catheters.

Allopurinol↗
PubMed1984

Clinical experience with long-term bendroflumethiazide treatment in calcium oxalate stone formers.

Bendroflumethiazide was administered to 85 patients (62 men, 23 women) with recurrent calcium oxalate stone disease. Side effects leading to interrupted treatment were observed in 26 (31%) of the patients. Fifty-nine (40 men, 19 women) remained on treatment for a mean (+/- SD) period of 3.7 +/- 1.0 years, and 21 reported late side effects. Twenty patients were given 2.5 mg bendroflumethiazide daily (Group A), 27 were given 2.5 mg twice daily (Group B), and 12 were given 5 mg once daily (Group C). Eight patients (14%) formed new stones and another two demonstrated stone growth during treatment. A beneficial effect on stone formation was observed in Groups B and C but not in Group A. Patients who failed to respond to treatment had a pre-treatment stone formation rate of 0.74 stones per year compared with 0.22 in those who did not form new stones. Those with recurrence during treatment had a lower citrate excretion than other patients. No effect on urinary citrate was recorded during treatment, and long-term treatment with bendroflumethiazide did not affect oxalate excretion.

Adult↗
PubMed1984

Skeletal muscle morphology, metabolism and function in smokers and non-smokers. A study on smoking-discordant monozygous twins.

Differences in skeletal muscle characteristics between smokers and non-smokers have been demonstrated in a previous study ( Orlander , J. et al. 1979, Acta Physiol Scand 107:39-46). In order to decide whether these differences had a genetical background, six pairs of smoking-discordant monozygous twins were studied with respect to muscle (vastus lateralis) morphology, metabolism and function. The percentage type I fibres was lower in the smokers, who also had smaller diameters of this fibre type. Cytochrome oxidase activity was decreased in the smokers. No differences were seen for other enzymes of energy metabolism, capillary density, isometric or dynamic strength, or short-term muscular endurance. The non-smokers tended to be more physically active. In four ex-smoker/non-smoker pairs, no significant differences were found for the investigated parameters. It was concluded, that the difference in fibre type distribution is not due to a hereditary predisposition to take up smoking. Furthermore, the small difference in physical activity level is an unlikely cause. Thus, smoking per se appears to be the most plausible explanation for the difference in fibre type distribution and associated muscle characteristics. No definitive conclusion regarding the reversibility of the smoking-related differences can be drawn from the present results.

Adult↗
PubMed1984

Induced development of proximal tubular NaKATPase, basolateral cell membranes and fluid reabsorption.

We have previously demonstrated that adrenal corticoid hormones (ACH) induce NaK-ATPase activity in immature proximal tubular (PT) cells in rats. We have now determined the effect of betamethasone (beta) and aldosterone (aldo) on the size of PT basal and lateral cell membranes (BLM), PT fluid reabsorption (J v (a] measured in vivo with the split drop technique and PT NaKATPase activity in 20-day-old (young) and 40-day-old (adult) rats. Serum levels of ACH were the same in young and in adult rats, but adrenalectomy caused a significantly larger fall in NaKATPase activity in young than in adult rats. BLM surface area (micron 2/micron -3 cell volume), J v (a) and NaKATPase were significantly lower in young than in adult rats. Three-day treatment with high doses of beta (60 micrograms X 100 g-1 or aldo (40 micrograms X 100 g-1) significantly increased BLM surface area. J v (a) and NaKATPase activity in young but not in adult rats. Three days after adrenalectomy, J v (a) was significantly depressed in adult rats. There was a significant correlation between the ACH-dependent changes in NaKATPase activity and J v (a). Short-term treatment (2-3 hours) with high doses of ACH did not significantly increase NaKATPase activity and J v (a) in young rats.

Adrenalectomy↗
PubMed1984

Diurnal variation of urine composition in calcium oxalate stone disease during treatment with bendroflumethiazide.

Urine samples, collected hourly between 6.00 and 23.00 h and in one single night fraction, were analyzed for calcium (Ca) and magnesium (Mg) before and during daily administration of 5 mg bendroflumethiazide to 13 Ca-oxalate (CaOx) stone formers. In some of them urinary oxalate (Ox), citrate and sodium were analyzed as well. Bendroflumethiazide was administered in divided doses to 7 and in a single dose to 6 patients. After 4-8 weeks of treatment urinary Ca decreased by approximately 25% in both groups and the reduction was evenly distributed over the day. The reduction of the Ca/Mg quotient and the CaOx risk index was most pronounced following meals. The AP(CaOx) index, an estimate of the CaOx ion activity product, was favorably reduced. No important differences were recorded for the different types of bendroflumethiazide administration and thus one single dose might be equally as efficient as two divided doses.

Adult↗
PubMed1984

Effects of a concentrated bran fibre preparation on HDL-cholesterol in hypercholesterolaemic men.

The effect of adding a purified form of wheat fibre (10.5 g/d) to a lipid-lowering diet was investigated in a placebo-controlled, double-blind, cross-over study (two 8-week periods) in 12 males (36-46 years old) with hypercholesterolaemia. Normolipidaemic men (n = 14, 45-46 years old) were used as controls in evaluation of the seasonal variation of serum lipids and lipoproteins in untreated subjects. Addition of wheat fibre was associated with non-significant decreases in cholesterol in very low and low density lipoproteins and a significant increase in cholesterol in high density lipoprotein. Serum cholesterol was unchanged in the treatment group but increased in the untreated control group. It is concluded that enrichment of a lipid-lowering diet with concentrated wheat fibre may be of value in the treatment of hypercholesterolaemia.

Adult↗
PubMed1984

Reduced intestinal permeability to low-molecular-weight polyethyleneglycols (PEG 400) in patients with jejunoileal bypass.

The intestinal permeation and 6-hour urinary recovery of small, multisized tracers, polyethyleneglycol 400 (PEG 400), was used to characterize gut permeability in nine patients after bypass surgery for morbid obesity and in ten healthy volunteers. In the patients, who also had hyperoxaluria, the urinary recovery of ingested PEG 400 was lower than in the healthy persons (10.9 and 24.7%). The patients also showed stronger intestinal exclusion of the larger polymers within the PEG 400.

Adult↗
PubMed1984

Subdivision of vaginal isolates of anaerobic curved bacteria based on genetic, morphologic, biochemical and gas-chromatographic/mass-spectrometric studies.

By DNA-DNA hybridization we could recognize two distinct groups of anaerobic curved rods (CR) that had been isolated from the vaginal content of women with bacterial vaginosis. On the basis of morphological studies these two groups correlated with one group of short, Gram-variable, curved rods (SCR) and another consisting of similar but somewhat longer rods (LCR). The SCR had up to four flagella per cell and the LCR up to eight. Among 79 biochemical tests, only tests for ONPG and arginine dehydrolase differentiated the two groups, SCR being positive and LCR negative. The gas chromatographic analysis of spent culture medium revealed that LCR, but not SCR, produced oxalacetic and oxalic acids. The groups were also differentiated by gas-chromatographic/mass-spectrometric patterns of certain cellular fatty aldehydes. Cell wall structure and presence of cytoplasmic inclusions did not distinguish SCR from LCR. On the basis of DNA-DNA hybridization values the SCR formed a more heterogeneous group than did LCR. Of all biochemical tests performed, only the production of alpha-galactosidase separated two strains of SCR that showed a low percentage of hybridization along with the rest of the SCR strains. Our study does not support a subdivision of SCR.

Aldehydes↗