Functional glomerular reserve in recipients of en bloc pediatric transplant kidneys.

BACKGROUND: The transplantation of an adequate renal mass is increasingly recognized to be of importance. The improved graft survival is probably due to a lesser risk of developing hyperfiltration-associated lesions. METHODS: We have reviewed the glomerular reserve in our recipients of en bloc pediatric transplant kidneys after an intravenous amino acid overload and compared them to single adult kidney transplant recipients. RESULTS: En bloc transplants evidenced increased glomerular filtration rate as compared with baseline as from the second hour of amino acid infusion (from 71+/-14 to 84.9+/-17 ml/min, 1.73 m2, P<0.05) and increased renal plasma flow as from the third hour (from 335+/-116 to 402+/-155 ml/min, 1.73 m2, P<0.05). In the single adult kidney recipient group, no change was seen either in the glomerular filtration rate (from 62.5+/-13 to 58.1+/-13 ml/min, 1.73 m2, P=NS) nor in renal plasma flow (from 354+/-125 to 304+/-98 ml/min, 1.73 m2, P=NS). CONCLUSIONS: These results show that patients receiving en bloc pediatric kidney transplantations have a greater renal functional reserve and show a lesser risk of hyperfiltration.

Occult lead intoxication as a cause of hypertension and renal failure.

BACKGROUND: The true incidence of lead (Pb) overload as a cause of chronic renal failure (CRF) is unknown. Also, it is unclear if CRF per se could generate an increment in the body Pb burden. Most studies of chronic Pb intoxication have been performed on cohorts or patients with a past history of occupational exposure. Therefore we studied the body Pb burden in CRF of known aetiology versus those patients with CRF with gout and hypertension of unclear aetiology without a past history of Pb exposure. In addition we studied patients diagnosed with essential hypertension. METHODS: We studied 296 patients lacking a past history of Pb exposure, who were subdivided into four groups: group I (n = 30), normal control subjects; group II (n = 104), patients with 'essential' hypertension and normal renal function; group III (n = 132), patients with CRF of uncertain aetiology in association with hypertension and/or gout, and group IV (n = 30), patients with CRF of known aetiology. The blood and urine Pb levels were assessed before and after an EDTA test. RESULTS: No abnormal test results were obtained for patients in groups I and IV. The EDTA test was abnormal in 16 patients (15.4%) in group II and in 74 patients (56.1%) in group III. A positive correlation was observed between plasma creatinine levels and post-EDTA urinary Pb in group III, but not in group I. No correlation regarding plasma creatinine and the duration of hypertension or gout were demonstrated. The bone Pb levels, measured in 12 patients with pathological EDTA test results, were positively correlated to the plasma creatinine levels. CONCLUSIONS: A high percentage of patients with gout, hypertension, and CRF have an excessive Pb burden, and about 15% of the patients diagnosed as 'essential' hypertensives also show high Pb burdens. It is remarkable that a history of overt Pb exposure was lacking in the whole study population.

Long-term erythropoietin in rats with reduced renal mass.

Hematocrit increase with recombinant erythropoietin (rEPO) has been associated with increased progression of renal insufficiency in experimental models of renal mass reduction. The aim of the present study was to assess the effects of therapy with rEPO and various antihypertensives on the progression of chronic renal insufficiency and on arterial hypertension in an experimental model of renal mass reduction. Rats subjected to a two-thirds nephrectomy were randomly assigned to an untreated control group or to therapy with rEPO (subcutaneously, at an initial dose of 40 U/kg thrice weekly), rEPO plus verapamil (subcutaneously, 0.5 mg/kg/day), or rEPO plus enalapril (orally, 50 mg/l in the drinking water). Combining enalapril and rEPO therapy controlled systemic blood pressure (BP) and the increase in proteinuria. Glomerular injury, as assessed 16 weeks after renal ablation, was more marked in the animals treated with rEPO with or without either antihypertensive. The morphometric analyses showed greater glomerular tuft areas in the three groups receiving rEPO than in the controls. The glomerular tuft area was directly correlated with the rate of glomerulosclerosis. In about 11% of the rEPO-treated hypertensive rats, the lesions showed severe hypertensive vasculopathy; in the animals treated with rEPO plus enalapril, the lesions were less severe. We conclude that therapy with rEPO was associated to renal damage which could not be attenuated by enalapril despite controlling BP and proteinuria, and may have a nonhemodynamic cause. Therapy with rEPO might trigger lesions usually associated with severe arterial hypertension; concomitant therapy with enalapril attenuates hypertensive vasculopathy.

Hemodialysis with acetate, DL-lactate and bicarbonate: a hemodynamic and gasometric study.

Using invasive techniques we have studied various hemodynamic and gasometric parameters in the course of hemodialysis (HD) with different buffers in an animal model. HD sessions of 180 minutes at zero ultrafiltration were carried out on three groups of eight uremic dogs each, under anesthesia and constant mechanical ventilation. The three groups differed only in the buffer used: acetate (Group AC), equal proportions of DL-lactate and acetate (Group AC+LA), and bicarbonate (Group BC). No hemodynamic changes were seen in Group BC. In the AC and AC+LA groups we observed on minute 1 a decrease of the mean blood pressure (MBP) and of the systemic vascular resistances (SVR). These parameters returned to baseline values within the first 30 minutes in Group AC+LA. In Group AC the SVR also returned to baseline values after the minute 30, but the MBP remained below baseline throughout the study period, together with cardiac index and left ventricular stroke work index decreases. Only in Group AC did we see a flattening of the ventricular function curves. Only in this Group was there a decrease of the arterial oxygen pressure (PaO2) with an associated increase of the alveolo-arterial and arterio-venous O2 differences. The O2 consumption was not modified in any of the groups. Acetate as a single buffer induces hemodynamic instability through peripheral vasodilation and reduction of myocardial contractility. The myocardial depression induced by acetate, in its turn, causes a reduction in PaO2. The mixed acetate+lactate buffer is hemodynamically better tolerated than acetate as single buffer, as it induces only vasodilation.

Antibiotic resistance and penicillin tolerance in clinical isolates of group B streptococci.

The aim of this study was to determine the susceptibility patterns of 100 group B streptococcal strains isolated in our hospital and to ascertain tolerance to penicillin by determining quantitative killing curves. We found two strains with intermediate susceptibility to penicillin and eight strains to ampicillin. Seventeen isolates were tolerant to penicillin, with bacterial counts decreasing 2 to 3 log during the first 8 h but still above 10(2) CFU/ml after 24 h. The kinetic study shows that penicillin tolerance is not rare among group B streptococci isolated in our hospital.

Antibiotic susceptibility of group A streptococci: a 6-year follow-up study.

The susceptibility patterns of group A streptococci over the last 6 years in our hospital were determined. Since our last study, carried out in 1987, all isolates have remained very susceptible in vitro to penicillin and all of the other beta-lactam agents tested. We observed resistance to erythromycin, clindamycin, tetracycline, and ofloxacin. The prevalence of erythromycin-resistant group A streptococci did not change appreciably throughout the study period.