Postanaesthetic myoglobinuric renal failure: an isolated expression of malignant hyperthermia.
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Biomedical subjects
Publications and source records attributed to A Sofia.
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Cardiac function and plasma levels of atrial natriuretic factor (ANF) were studied in a group of 38 patients with untreated essential hypertension and in a group of 31 well matched normotensive controls. ANF was slightly but significantly higher in hypertensives and was directly correlated with mean arterial pressure and inversely with plasma renin activity (PRA). Hypertensives showed normal systolic function and higher cardiac mass compared to controls. ANF was inversely correlated to echocardiographic indexes of left ventricular performance in the former group. At Doppler echocardiographic evaluation, hypertensives showed an impairment in diastolic function which was correlated to the increase in ANF levels. Stepwise multiple regression analysis performed with ANF as the dependent variable and several biohumoral and echocardiographic parameters as the independent variables showed that only cardiac diastolic function and PRA significantly affect ANF levels in hypertensives. In conclusion, an impairment in cardiac diastolic function may be responsible together with other factors for the increased ANF levels encountered in essential hypertension.
A previous report suggests that treatment with recombinant human erythropoietin (rH-EPO) significantly improves many abnormalities in circulating amino acids (AA) in hemodialysis patients. We evaluated the effects of a 12-month treatment with rH-EPO (150-250 U/kg/week) on blood AA levels in 10 patients with chronic renal failure under regular dialytic treatment. During treatment, hemoglobin levels increased from 7.0 +/- 0.3 to 10.1 +/- 0.3 g/dl at 3 months remaining steady thereafter. Before the treatment, patients showed reduced levels of essential AA (EAA), mainly valine, leucine and threonine (p < 0.05-0.01); among non-EAA (NEAA), aspartate and serine were reduced, whereas glycine, alanine, proline, citrulline and cyst(e)ine were increased (p < 0.05-0.001). Val/Gly, Ser/Gly and Tyr/Phe ratios were low (p < 0.05-0.01). Total EAA and total NEAA (619 +/- 21 and 1,382 +/- 75 mumol/l, respectively, before the study) were unchanged (639 +/- 22 and 1,410 +/- 89 mumol/l, respectively) at 12 months. Abnormalities in AA levels observed before the treatment persisted throughout the study. Only serine increased at the end of the study (p < 0.05). In conclusion, contrary to what has been reported, treatment with rH-EPO is not associated with an amelioration of AA metabolism in hemodialysis patients.
Sera from 82 haemodialysis patients were tested for anti-HCV, HCV-RNA, and HBsAg. Alanine aminotransferase (ALT) activity was monitored weekly for 2 months. Anti-HCV was positive in 31 patients (37.8%), showing different single-peptide patterns. HCV-RNA was detected in 26 anti-HCV-positive patients (84%) and also in two of 21 anti-HCV-negative patients. Twenty-seven (87%) of the 31 anti-HCV-positive patients had persistently normal ALT values; 22 of these patients were HCV-RNA positive. The four patients with elevated ALT values had HCV viraemia. HBsAg was positive in nine anti-HCV-negative patients. The close correlation between HCV viraemia and HCV status, independently of ALT values, requires that anti-HCV dialysis patients must be considered potentially infective and dialysed with reserved machines and/or in separate shifts.
Muscle protein turnover and amino acid (AA) exchange were studied in 4 patients with chronic renal failure (CRF) and in 5 controls in the postabsorptive state by using the forearm perfusion method together with the systemic infusion of 3H-Phe. In CRF patients muscle protein breakdown is increased and is associated with a parallel increase in protein synthesis. Protein breakdown is inversely related to arterial bicarbonate. Net proteolysis is unchanged. The release of total AA, glutamine and alanine is not different from controls, whereas the release of valine and leucine is reduced and serine uptake tends to be decreased. In conclusion, in postabsorptive patients with CRF, well before the uremic stage, an increased protein breakdown associated with metabolic acidosis takes place; net proteolysis is unaffected. Alterations in BCAA metabolism suggest the occurrence of increased BCAA degradation proceeding beyond the transamination step.
BACKGROUND: Despite continuing glucose absorption and stimulation of insulin secretion, wasting is common in patients with chronic renal failure (CRF) treated with peritoneal dialysis. METHODS: To evaluate if peritoneal dialysis per se has any effect(s) on muscle protein turnover we employed the forearm perfusion method associated with the kinetics of 3H-phenylalanine in seventeen patients with CRF in the basal state and: a) during the systemic hyperinsulinemia associated with peritoneal dialysis (6 patients) (200-240 min); b) during locally-induced hyperinsulinemia, without systemic effects on aminoacid (AA) availability (6 patients) (80-120 min); c) in time-controls (5 patients) (80-240 min). RESULTS: Peritoneal dialysis and local infusion of insulin in the brachial artery (0.01 mU/min/kg) induced a similar degree of systemic or local, moderate hyperinsulinemia (19+/-4 e 21+/-3 microU/ml, respectively). During both protocols an insulin-related inhibition of muscle protein degradation occurred; however peritoneal dialysis caused a 20% decrease in forearm phenylalanine rate of disposal (an index of muscle protein synthesis), which correlated with the decline of arterial BCAA and potassium, which were removed via the peritoneal fluid. Furthermore, a persistent negative net phenylalanine and AA balance across the forearm was observed during peritoneal dialysis, while the negative basal net phenylalanine and AA balance was reversed to a positive or neutral one during local hyperinsulinemia. CONCLUSIONS: We conclude that in CRF patients even a modest elevation in local insulin levels is followed by an anabolic muscle response, while the same effect is not observed during the systemic hyperinsulinemia associated with substrate removal which occurs during peritoneal dialysis. In this setting the antiproteolytic effect of hyperinsulinemia is offset by a decrease in muscle protein synthesis which is accounted for by a decrease in AA availability. Our data indicate that protein metabolism during peritoneal dialysis is characterized not only by decreased, but also less efficient, turnover rates.
Metabolic acidosis is a common complication in patients with advanced chronic renal diseases and dialytic treatments are unable to correct it completely. In hemodialysis (HD) patients, severe metabolic acidosis is associated with an increased risk of death. Evidence from several experimental studies suggests that even mild metabolic acidosis is associated with systemic effects. Acidosis is implicated in endocrine changes and has negative repercussions on bone and protein metabolism. In addition, recent observations suggest that acidosis triggers inflammation and accelerates the progression of chronic kidney diseases. As a contradictory finding, acidosis can reduce circulating leptin. Clinical studies on the nutritional effects of metabolic acidosis correction have shown mildly favorable effects. Taking into account the systemic effects of metabolic acidosis it is suggested that even mild metabolic acidosis is corrected. However, the new findings concerning the systemic effects of acidosis must be evaluated in controlled trials.