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Biomedical subjects

G Barba

Publications and source records attributed to G Barba.

At least 55 records · Page 3Linked to original sources

Red blood cell sodium-lithium countertransport, blood pressure, and uric acid metabolism in untreated healthy men.

The relationship of red blood cell (RBC) Na/Li countertransport to the renal handling of lithium and uric acid was investigated in a sample of 176 untreated men. Subjects in the upper quintile of the Na/Li countertransport distribution (n = 40), compared to those in the two lower quintiles (n = 72), had higher serum uric acid levels (0.34 +/- 0.06 v 0.29 +/- 0.05 mmol/L, P less than 0.001) and systolic blood pressure (131 +/- 19 v 123 +/- 16 mm Hg, P less than 0.02) and slightly lower fractional excretion of uric acid (7.5 +/- 1.5 v 8.4 +/- 2.6%, P less than 0.08). The lithium fractional excretion was not significantly related to either blood pressure or RBC Na/Li countertransport. The altered uric acid metabolism in individuals with high RBC Na/Li countertransport could be the expression of an abnormality of renal tubular function.

Biological Transport↗

Altered renal tubular function in men with high erythrocyte sodium-lithium countertransport.

The renal fractional excretion of uric acid was determined for both a habitual diet and an NaCl-restricted diet in two groups of untreated subjects with low (117-207 mumol per litre of cells per h) and high (373-598 mumol per litre of cells per h) erythrocyte Na-Li countertransport identified in a population-based survey of middle-aged male workers. The group with high Na-Li countertransport had a higher mean blood pressure (P less than 0.05); this group also had a significantly reduced fractional excretion of uric acid with the NaCl-restricted diet even after adjustment for the difference in blood pressure (P less than 0.03). These findings are compatible with an abnormality in kidney tubular function and possibly in the renal handling of sodium in subjects with elevated erythrocyte Na-Li countertransport.

Biological Transport↗

Atrial natriuretic peptides and tubular sodium handling during normal daily life in men.

The relationship between segmental renal tubular sodium handling (using the renal clearance of ingested lithium as a marker of proximal tubular sodium handling) and circulating plasma levels of atrial natriuretic factor (ANF) was studied in a sample of 295 untreated men drawn from a male population at work under their usual living conditions. Plasma ANF was positively and significantly related to sodium excretion at the distal nephron, indicating that this hormone interacts with a distal renal tubular site to influence the control of sodium excretion in man.

Adult↗

Familial cases of boutonneuse fever.

Pairs of cases of Boutonneuse Fever (BF) occurred in three families. The illness appeared almost simultaneously in both members of each family, but was generally more serious in one as judged by clinical and laboratory parameters. The possibility of a "bed rickettsiosis", that is reactivation of rickettsiae by the blood meal obtained from the first individual by the same tick which fed upon the second individual, could be excluded in two of the three pairs of cases. In only one of the case pairs were the individuals sharing the same bed. The differences in severity of symptoms may be related to the different immunological pattern observed in these patients. Previous rickettsial infection may have provided partial immune protection, as is repeatedly reported in the literature. In one couple, the more seriously ill patient had antibodies of the IgM class, suggesting that this was his first exposure to Rickettsia conorii. The less severely ill patient had antibodies of the IgG class only, presumably as the result of re-exposure after previous asymptomatic infection with spotted-fever-group rickettsia.

Adult↗

Renal handling of sodium after an oral protein load in adult humans.

This investigation was designed to study (1) renal sodium handling after an oral protein load and (2) its relationship to some known determinants of the hemodynamic response (glucagon, insulin, growth hormone, renin, aldosterone, and plasma amino acid concentration). To this end of group of 8 adult subjects was studied before (three 30-min clearances) and after a meat meal (MM; five 30-min clearances at 30, 60, 90, 120 and 180 min). The MM provided 2 g/kg BW of protein. Within 30 min from the MM an hyperfiltration response was seen, which was paralleled by a 2-fold increase in plasma alanine concentration while total plasma amino acid concentration was not different from the baseline values. The hemodynamic response was associated with a normally operating tubuloglomerular feedback mechanism independent of renin-aldosterone activity, but possibly associated with an early increase in plasma glucagon concentration and later on with a modest increase in postmeal plasma insuling concentration.

Adult↗