Biomedical subjects

G Tonolo

Publications and source records attributed to G Tonolo.

75 records · Page 5Linked to original sources

PubMed1986

Plasma alpha natriuretic peptide in cardiac impairment.

Regional plasma alpha human atrial natriuretic peptide concentrations were measured, and their relation to intracardiac pressures assessed, in an unselected series of 45 patients undergoing diagnostic cardiac catheterisation. Arteriovenous gradients in plasma concentrations of alpha human atrial natriuretic peptide were consistent with its cardiac secretion and its clearance by the liver and kidneys. Plasma concentrations of the peptide in the pulmonary artery, aorta, and superior vena cava correlated closely with the mean right atrial and pulmonary arterial pressures, and similar, though weaker, positive relations were seen with the left ventricular end diastolic and pulmonary artery wedge pressures. Concentrations of both atrial natriuretic peptide and renin showed significant inverse relations with serum sodium concentrations. Plasma concentrations of alpha human atrial natriuretic peptide are an additional objective indicator of the severity of haemodynamic compromise in patients with cardiac impairment.

Adolescent↗

PubMed1986

Plasma atrial natriuretic peptide: responses to modest and severe sodium restriction.

Plasma atrial natriuretic peptide (ANP), active renin and aldosterone concentrations were measured during modest and severe sodium restriction in 16 normal volunteers. Eight volunteers took, in two separate 4-day periods, diets containing 200 and 15 mmol sodium/day (plus frusemide, 40 mg, on day 1 of low sodium intake), in random order. With sodium restriction plasma ANP concentrations fell in parallel with cumulative sodium balance. Changes in plasma renin and aldosterone were reciprocal to those in plasma ANP. To assess the threshold and reproducibility of the effects of modest sodium restriction on plasma ANP concentrations, a further group of eight volunteers took identical constant sodium diets (80 mmol/day in two cases and 120 mmol/day in the remainder) for 4 days on two successive weeks. On both occasions similar individual and mean falls in plasma ANP values accompanied the small net sodium loss occurring on these regimes. Plasma active renin concentration rose significantly during both diet phases. These data suggest plasma ANP concentrations alter in response to minor changes in sodium status, and are consistent with a role for plasma ANP in physiological regulation of body fluid volumes.

Adult↗

PubMed1983

Trypsin-activatable inactive renin in rat plasma.

1. Activation of inactive renin in rat plasma has been studied with different trypsin concentrations and incubation times at pH 6.2 and 4 degrees C. 2. Trypsin concentrations below 2 mg/ml, lower than endogenous rat plasma anti-trypsin activity, do not activate inactive renin, whereas maximal activation is obtained with trypsin at 6 mg/ml for 1 min at 4 degrees C, pH 6.2. 3. Under these conditions trypsin can cleave dialysable fragments from renin substrate. ANG I can be generated at 37 degrees C with a pH optimum of 5.3. Nevertheless, the ANG I formation at pH 6.2 was totally unaffected. 4. Incubations longer than 2 min with trypsin at 6 mg/ml can induce a direct cleavage of dialysable ANG I-containing fragments strongly interfering with the measurements of renin activity at pH 6.2. 5. On average 40% of the total renin measured in plasma of normotensive WK rats is in the inactive form, although a wide range of variation is observed.

Angiotensin I↗