Effect of supplemental oxygen on supramaximal exercise performance and recovery in cystic fibrosis

Shah, Ashish R., Thomas G. Keens, and David Gozal.Effect of supplemental oxygen on supramaximal exercise performance and recovery in cystic fibrosis. J. Appl.Physiol. 83(5): 1641-1647, 1997.The effects ofsupplemental O₂ on recovery fromsupramaximal exercise and subsequent performance remain unknown. Ifrecovery from exercise could be enhanced in individuals with chroniclung disease, subsequent supramaximal exercise performance could also be improved. Recovery from supramaximal exercise and subsequent supramaximal exercise performance were assessed after 10 min of breathing 100% O₂ or room air(RA) in 17 cystic fibrosis (CF) patients [25 ± 10 (SD) yrold, 53% men, forced expired volume in 1 s = 62 ± 21%predicted] and 17 normal subjects (25 ± 8 yr old, 59% men,forced expired volume in 1 s = 112 ± 15% predicted). Supramaximalperformance was assessed as the work of sustained bicycling at a loadof 130% of the maximum load achieved during a graded maximal exercise.Peak minute ventilation(E) andheart rate (HR) were lower in CF patients at the end of eachsupramaximal bout than in controls. In CF patients, single-exponentialtime decay constants indicated faster recovery of HR(_HR = 86 ± 8 and 73 ± 6 s in RA and O₂,respectively, P < 0.01). Similarly, fast and slow time constants of two-exponential equations providing thebest fit for ventilatory recovery were improved in CF patients duringO₂ breathing ( = 132.1 ± 10.5 vs. 82.5 ± 10.4 s; = 880.3 ± 300.1 vs. 368.6 ± 107.1 s,P < 0.01). However, no such improvements occurred in controls. Supramaximal performance after O₂ improved in CF patients (109 ± 6% of the 1st bout after O₂ vs. 94 ± 6% in RA, P < 0.01).O₂ supplementation had no effect on subsequent performance in controls (97 ± 3% inO₂ vs. 93 ± 3% in RA). Weconclude that supplemental O₂after a short bout of supramaximal exercise accelerates recovery andpreserves subsequent supramaximal performance in patients with CF.

     

Increased cathepsin D-like activity in cortex, tubules, and glomeruli isolated from rats with experimental nephrotic syndrome.

We have examined the activity and distribution of cathepsin D (EC 3.4.23.5), a major renal lysosomal endoproteinase, in the various anatomical and functional areas of normal rat kidney. Cathepsin D-like activities (delta A280/h per mg of protein) in normal rat tissues were: cortex, 0.78 +/- 0.05, n = 37; medulla, 0.62 +/- 0.03, n = 12; papilla, 0.63 +/- 0.04, n = 12; tubules, 0.74 +/- 0.04, n = 28; glomeruli, 0.59 +/- 0.03, n = 28; and liver, 0.41 +/- 0.02, n = 28. Enzyme activity was maximal at pH 3.0-3.5 and inhibited more than 90% by pepstatin (6.7 micrograms/ml), suggesting that the enzyme is cathepsin D. In subsequent experiments we measured cathepsin D-like activity in cortex, tubules and glomeruli isolated from rats with puromycin aminonucleoside (PAN)-induced nephrotic syndrome. Treated animals (15 mg of PAN/100g body wt., intraperitoneally) developed proteinuria beginning 4 days after injection and exceeding 900 mg/24h on day 9. In two separate experiments involving 52 animals we observed a significant increase in cathepsin D-like activity in cortex (+82.7%), tubules (+109.6%) and glomeruli (+54.7%) isolated from PAN-treated rats killed during marked proteinuria (day 9, mean total urinary protein excretion: 937 +/- 94 mg/24h). This increase was observed whether the activity was expressed per mg of DNA or per mg of protein. Increased cathepsin D-like activity was first observed in cortex and tubules coincident with the onset of proteinurea (day 4, mean total urinary protein excretion: 112 +/- 23 mg/24h). In contrast with the significant elevation of renal cathepsin D-like activity, the activity (nmol/h per mg of protein) of alpha-L-fucosidase (EC 3.2.1.51), a non-proteolytic enzyme, was markedly decreased in the identical samples used for the measurement of cathepsin D-like activity: cortex (-46.4%); tubules (-46.1%); and glomeruli (-38.5%). In addition to changes in renal enzyme activities, PAN-treated rats excreted large amounts of cathepsin D-like activity in their urine (beginning on day 3) compared with nearly undetectable cathepsin D-like activity in the urine from control rats. The significant increases in glomerular and tubular cathepsin D activity may reflect an important role for this enzyme in the pathophysiology associated with PAN-induced nephrotic syndrome.     

Detection of vitamin B12 and pantothenic acid in cell exudates of blue-green algae

The blue-green algaeChroococcus, Oscillatoria and Nostoc, excrete vitamin B₁₂ and pantothenic acid in the culture filtrates during the phase of active growth. The excretion has an ecological significance.     

Neutralizing antibodies to simian papovavirus SA12 in Old World primates in laboratory colonies: high prevalence in baboons

Sera from 517 laboratory-housed nonhuman primates representing five genera and from 13 laboratory workers were examined for the presence of neutralizing antibodies to SA12 virus. The antibody prevalences were as follows: baboons, 66%; patas and vervet monkeys, 24%; macaques, 8%, and chimpanzees, 2%. The serum of one laboratory worker had antibodies. These results suggest that SA12 virus is a common infection of nonhuman primates in laboratory colonies, especially baboons.     

Microbial transformation of sterols

Summary Arthrobacter simplex, Serratia marcescens, Fusarium and Mycobacterium were tested for their ability to transform phytosterol to Androsta 1, 4 diene 3, 17 dione (ADD). Arthrobacter simplex ATCC 6946 was found to be more efficient than the other species tested.     

Role of adrenals on the 24-hour periodicity in hypothalamo-pituitary axis in male rat

Studies were carried out to investigate the influence of adrenalectomy on the 24 hour periodicity in the hypothalamo-pituitary axis in adult male rat. Adrenal gland ablation resulted in the shift in the occurrence of peak content of hypothalamic LHRH and attenuation in the responsiveness of the pituitary to synthetic LHRH. Following adrenalectomy, the circadian serum LH peak was attenuated and serum FSH showed a 24 hour periodicity. In conclusion, the results suggest the possible role of adrenal gland in the maintenance of 24 hour periodicity of hormones in the hypothalamo-hypophyseal axis in male rat.     

Study of the atherogenic dyslipoproteinemia induced by dietary cholesterol in rhesus monekys (Macaca mulatta).

Hypercholesterolemia was induced in adult male rhesus monkeys with a high-fat diet containing an elevated cholesterol level (0.5%). Plasma lipoproteins were chromatographically separated into four size populations (regions) that were subdivided by density until fractions with single electrophoretic mobilities were obtained. The region III lipoproteins (LDL) contained 80% of plasma cholesterol and were present in the highest concentration of all fractions. Their molecular weight was increased over that of controls so that each particle averaged 1.8 times the number of cholesteryl ester molecules as did control LDL. Region II lipoproteins, a heterogeneous group, were present in next highest concentration. Most were cholesteryl ester-rich, beta-migrating lipoproteins that overlapped the VLDL and LDL density ranges; apoB was the predominant apoprotein. One region II subfraction had pre beta 2 migration and the density range. 1.050 less than d less than 1.10. Another subfraction, cholesteryl ester-rich VLDL including only about 1% of plasma cholesterol, had pre beta 1 migration and apoB and apoC as the predominant apoproteins with no apoprotein E. Region I lipoproteins were larger sized, slow beta-migrating cholesteryl ester-rich VLDL that included 5% of plasma cholesterol. ApoB and apoE were the predominant apoproteins. Region IV lipoproteins (HDL) contained 4% of the plasma cholesterol; their concentration was decreased to about 1/3 of the control level. Atherogenic features of the diet-induced dyslipoproteinemia included the increased plasma concentrations and cholesteryl ester contents of the region I, II, and III lipoproteins in addition to the decreased HDL concentration.