Hypoxia is not the primary mechanism contributing to exercise-induced proteinuria

Introduction

Proteinuria increases at altitude and with exercise, potentially as a result of hypoxia. Using urinary alpha-1 acid glycoprotein (α1-AGP) levels as a sensitive marker of proteinuria, we examined the impact of relative hypoxia due to high altitude and blood pressure-lowering medication on post-exercise proteinuria.

Methods

Twenty individuals were pair-matched for sex, age and ACE genotype. They completed maximal exercise tests once at sea level and twice at altitude (5035 m). Losartan (100 mg/day; angiotensin-receptor blocker) and placebo were randomly assigned within each pair 21 days before ascent. The first altitude exercise test was completed within 24–48 hours of arrival (each pair within ~1 hour). Acetazolamide (125 mg two times per day) was administrated immediately after this test for 48 hours until the second altitude exercise test.

Results

With placebo, post-exercise α1-AGP levels were similar at sea level and altitude. Odds ratio (OR) for increased resting α1-AGP at altitude versus sea level was greater without losartan (2.16 times greater). At altitude, OR for reduced post-exercise α1-AGP (58% lower) was higher with losartan than placebo (2.25 times greater, p=0.059) despite similar pulse oximetry (SpO₂) (p=0.95) between groups. Acetazolamide reduced post-exercise proteinuria by approximately threefold (9.3±9.7 vs 3.6±6.0 μg/min; p=0.025) although changes were not correlated (r=−0.10) with significant improvements in SpO₂ (69.1%±4.5% vs 75.8%±3.8%; p=0.001).

Discussion

Profound systemic hypoxia imposed by altitude does not result in greater post-exercise proteinuria than sea level. Losartan and acetazolamide may attenuate post-exercise proteinuria, however further research is warranted.

Human papillomavirus types 16 and 18 in carcinomas of the penis from Brazil

Human papillomavirus (HPV) type-16 DNA sequences were found in 26/53 (49%) and HPV type-18 in 5/53 (9%) of penile cancers. In only one specimen was HPV18 found on its own. HPV16 sequences were integrated into the host cell chromosomes although some monomeric and oligomeric free forms of DNA were detected in a few tissues. HPV18 was, as far as detectable, free and unintegrated in all tissues tested. HPV16 DNA was also detected in 40% of cases of carcinoma of the cervix in 19 women from the same social groups as the males. The viral DNA in the female cases was a mixture of integrated and free forms. The DNA binding protein (ICSP 11/12) of herpes simplex type 2 (HSV2) was not detected in 10 penile cancers tested with a monoclonal antibody.

Serum secretory component: a potential marker of biliary obstruction

Secretory Component (SC) was measured in serum samples from patients with a variety of disorders using enzyme-linked immunosorbent assay (ELISA). The overall precision of the method at high and low concentrations of SC was 11% (CV). Serum concentrations of SC were significantly higher in patients with several forms of liver disease (means = 82.37 mg/l +/- SD 56.9) compared with normals (means = 6.0 +/- SD 4.2), patients with diseases of mucosal surfaces (means = 7.4 mg/l +/- SD 4.2) and patients with elevated alkaline phosphatase due to causes other than overt liver disease (means = 16.4 mg/l +/- SD 7.6). Serum SC levels correlated strongly with serum alkaline phosphatase activity (rs = 0.648) in the presence of liver disease. Raised serum SC in liver disease probably reflects reflumeans of biliary SC and secretory IgA into blood due to cholestasis. Estimation of serum SC could be clinically useful as an index of biliary obstruction, especially to distinguish a raised serum alkaline phosphatase activity of liver or bone origin.