Biomedical subjects

P Van Loon

Publications and source records attributed to P Van Loon.

11 recordsLinked to original sources

PubMed1990

Respiratory symptoms and pulmonary function in Saskatchewan farmers.

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Adult↗

PubMed1989

Renal and systemic effects of short-term high protein feeding in normal rats.

Various studies have shown that a high protein (HP) diet, compared to a low protein (LP) diet, leads to hypercalciuria and alterations in renal and systemic hemodynamics. The authors compared the effects of HP diet to those of normal protein diet (NP) to determine the possible mechanisms by which changes in systemic hemodynamics and hypercalciuria occurred. The studies were conducted in awake rats; the effects of dietary sodium content on the changes induced by HP also were evaluated. The relationship of prostaglandins (PG), renin (PRA), and aldosterone (PA) to changes in blood pressure (BP) was assessed. Two weeks after HP and normal sodium feeding (40%), glomerular filtration rate (GFR) and urine flow (V) were not different from the same values in a group on an NP diet (23%). When HP was fed with low sodium, there was a rise in V as a consequence of greater fluid intake. Although plasma calcium remained constant, the hypercalciuria correlated with high protein and sodium content. Alterations in 1,25(OH)2 vitamin D3 or PTH (cyclic AMP excretion) function did not explain the hypercalciuria induced by HP. This suggests that HP leads to inhibition of tubular calcium reabsorption by mechanism(s) yet to be elucidated. Although HP did not alter GFR, it led to an increase in BP, a fall in renal vascular resistance, and an increase in RPF, regardless of sodium intake. PRA and urine PGE2 excretion were significantly higher in the rats on HP diet, whereas PA remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Respiratory symptoms and pulmonary function in farmers.

A questionnaire was given to 1,824 farmers and 556 control subjects in Saskatchewan to assess respiratory health and pulmonary function tests. With data corrected for age and smoking, farmers were found to have increased prevalences of the respiratory symptoms of phlegm, wheeze, shortness of breath, and the condition of chronic bronchitis. In addition, farmers had significantly lower values for the pulmonary function test variables forced vital capacity (FVC), forced expired volume in one second (FEV1) and maximum midexpiratory flow rate. However, the FEV1/FVC ratio was slightly but significantly greater in farmers than in control subjects. These findings suggest an increase in respiratory symptoms in farmers compared with rural control subjects who are not farmers and a decrease in lung volume and expired flow rates. The slightly high FEV1/FVC ratio may indicate a mixed obstructive and restrictive picture.

Adult↗

PubMed1977