Renal function impairment induced by change in posture in patients with cirrhosis and ascites

The assumption of upright posture by patients with liver cirrhosis leads to striking activation of adrenergic and renin-angiotensin systems. The tilting-induced modifications in renal function of eight healthy controls and 14 untreated patients with liver cirrhosis and ascites were related to plasma concentrations of noradrenaline, renin activity and aldosterone. All patients had preserved renal blood perfusion. All parameters were evaluated during bed rest for two hours and in the sitting posture for one hour. Basal plasma renin activity (0.1 greater than p greater than 0.05), aldosterone and noradrenaline concentrations (p less than or equal to 0.01) were raised in cirrhotics. The renal function tests (creatinine clearance, filtered sodium, tubular rejection fraction, urinary sodium excretion) were significantly reduced in cirrhosis. Under basal conditions, in cirrhotic patients tubular rejection fraction and urinary sodium excretion were inversely related to both noradrenaline and aldosterone concentrations. After tilting, the noradrenaline and aldosterone integrated outputs (sigma delta) were significantly greater in cirrhosis. All renal function tests significantly decreased in cirrhotics, whereas creatinine clearance only significantly decreased in controls. Patient's tubular rejection fraction of sodium and sodium excretion were related to sigma delta aldosteronaemia (r = -0.72; p less than 0.01), but no longer to sigma delta plasma noradrenaline.

Superinfections during antimicrobial treatment with betalactam-aminoglycoside combinations in neutropenic patients with hematologic malignancies

The frequency, etiology and risk factors of superinfections during and/or within one week after antibiotic therapy with betalactam-aminoglycoside combinations were evaluated in 631 patients with hematologic malignancies admitted to the Institute of Hematology of Rome from January 1982 to December 1984. 356 patients (56%) developed 402 episodes of proven or presumed infection. Of these patients, 78 developed 102 superinfections. Overall, superinfections responded less satisfactorily to antibiotic therapy than the primary febrile episodes (63% vs. 85%). The distribution of etiologic agents of superinfections differed from those responsible for primary infections, since fungi and anaerobes (especially Clostridium difficile) were mostly isolated after antibiotic therapy had begun. Moreover, among aerobic bacteria, frequently antibiotic-resistant species, such as Pseudomonas aeruginosa, Streptococcus faecalis and Staphylococcus epidermidis were the leading etiologic agents of superinfection. The risk of superinfection appeared to increase with the depth and persistence of granulocytopenia. On the other hand, the length of hospitalization, length of previous antibiotic therapy, previous chemoprophylaxis and presence of indwelling venous catheter did not affect the risk of superinfection.

Comparative in vitro activity of aztreonam, other beta-lactam antibiotics and aminoglycosides against Pseudomonas aeruginosa

Aztreonam, ceftriaxone, moxalactam, cefotaxime, cefsulodin, cefoperazone, piperacillin, azlocillin, carbenicillin, amikacin, gentamicin, tobramycin, sisomicin and dibekacin were tested by broth dilution against 161 isolates of Pseudomonas aeruginosa. Seventy-one of these strains were selected for their resistance to carbenicillin and aminoglycosides and classified as "multiply resistant" strains. Over all, aztreonam showed the greatest antipseudomonal activity by far, followed by ceftriaxone, moxalactam, cefotaxime and amikacin. Piperacillin, azlocillin, cefsulodin, and cefoperazone were highly active against carbenicillin and/or aminoglycoside-susceptible P. aeruginosa strains, but were also poorly inhibitory against multiply resistant isolates.

Aldosterone related blood volume expansion in cirrhosis before and during the early phase of ascites formation

Thirty-seven patients with liver cirrhosis (16 without ascites: group 1; 21 with untreated ascites at the first onset: group 2) were studied during controlled sodium intake (40 mmol/day). Renal plasma flow, glomerular filtration rate, urinary sodium excretion, plasma sodium and potassium, plasma renin activity, plasma aldosterone concentration, blood volume, and arterial pressure were evaluated. All the patients had normal renal perfusion, plasma sodium and potassium, and arterial pressure. Mean plasma renin activity and plasma aldosterone concentration were significantly depressed in group 1 (p less than 0.001, p less than 0.005 respectively) compared with 21 normal controls in identical experimental conditions. This was possibly a consequence of expanded blood volume (p less than 0.001 compared with controls) which was directly correlated with plasma aldosterone concentration (p less than 0.001). In group 2 plasma renin activity and plasma aldosterone concentration were normal in over 50% of cases. Blood volume was lower than in group 1 (p less than 0.002), but again related to plasma aldosterone concentration (p less than 0.01). In both groups plasma aldosterone concentration was hyperbolically and inversely correlated with urinary sodium excretion, but the two curves were progressively shifted to the left in respect to controls suggesting an enhanced renal tubular sensitivity to the hormone. The results suggest that aldosterone related renal sodium retention, with consequent blood volume expansion, occurs before ascites formation. The mineralocorticoid activity of aldosterone is amplified by an enhanced sensitivity of renal tubules which appears to increase as the disease progresses.

Impairment of blood pressure control in patients with liver cirrhosis during tilting: study on adrenergic and renin-angiotensin systems

Mean arterial pressure, phenylalanine, tyrosine, norepinephrine and plasma renin activity (PRA) were determined in the plasma of 6 healthy controls and 8 patients with liver cirrhosis receiving a controlled sodium intake (40 mEq/day), after 1 h of bed rest and 10 min after being tilted up at 90 degrees. After resting, patients showed lower arterial pressure (p less than 0.025) and higher plasma levels of phenylalanine (p less than 0.005), tyrosine (p less than 0.05), norepinephrine (n.s.) and PRA (n.s.) than controls. In spite of a prolonged and marked stimulation of the adrenergic system induced by tilting, arterial pressure of cirrhotics, after an initial increase, decreased significantly. A significant PRA increase was observed in both groups but in patients it was greater and lasted longer, up to 30 min, when PRA and arterial pressure were inversely and significantly correlated. The adrenergic system of cirrhosis then appeared unable to maintain adequate levels of arterial pressure, even though hyperstimulated. The renin-angiotensin system played an important compensatory role in this contest.

[Catecholamine and renin-angiotensin system in blood pressure control in patients with liver cirrhosis]

The changes induced by active tilting in arterial pressure, plasma renin activity, norepinephrine and its precursors phenylalanine and tyrosine were evaluated in 8 patients with liver cirrhosis and 6 healthy controls. The results suggest the inability of the adrenergic system, though hyperstimulated, to maintain arterial pressure homeostasis in cirrhosis with a compensatory hyperactive renin-angiotensin system. Derangements in catecholamine synthesis, possibly due to altered utilisation of precursors to alternative final products (weak neurotransmitters?) can be taken into account.