Malignant hypertension: a syndrome associated with low plasma kininogen and kinin potentiating factor.

Plasma levels of kininogen, kallikrein, and prekallikrein were determined in patients with malignant hypertension (MH) and compared to normotensive controls (NC) and patients with mild to moderate essential hypertension (EH). Also, a recently described kinin potentiating factor (KPF) was estimated by dividing the value of kininogen determined by trypsin (Kgn-Try) by that of kininogen determined by human urinary kallikrein (Kgn-HuUk). No significant alterations were detected among plasma values of pre-kallikrein and kallikrein of MH as compared to NC. However, Kgn-HuUK values were significantly lower in MH (1.9 +/- 0.3 micron gLBK/ml) as compared to EH and NC (2.7 +/- 0.1 micron gLBK/ml and 3.0 +/- 0.2 micron gLBK/ml respectively, p less than 0.05). Furthermore, KPF values were also low (p less than 0.05) in MH (1.6 +/- 0.3) when compared with similar values obtained in EH and NC (3.0 +/- 0.2 and 2.8 +/- 0.1, respectively). Adequate control of blood pressure levels for 90 days in MH group caused no significant alterations in plasma levels of kininogen and KPF. It is suggested that diminished kininogen levels as well as a decrease in a kinin potentiation KPF that is generated in plasma by trypsin may be involved in the pathogenesis of human malignant hypertension.

Inadequate aldosterone response to hyperkalemia during angiotensin converting enzyme inhibition in chronic renal failure.

To assess the mechanism involved in hyperkalemia during angiotensin converting enzyme inhibition with captopril in chronic renal failure, captopril, 150 mg/day, was administered to 16 patients with hypertension with plasma creatinine levels between 1.6 and 12.4 mg/dl. After 4 weeks of therapy, plasma potassium levels increased from 3.9 +/- 0.1 to 5.5 +/- 0.2 mEq/L (P less than 0.001) and the final plasma potassium levels correlated with plasma creatinine levels (r = 0.67; P less than 0.01). In six patients with plasma creatinine levels greater than or equal to 3 mg/dl, aldosterone excretion decreased after 4 weeks of captopril, from 7.5 +/- 3.1 to 1.8 +/- 0.5 micrograms/24 hr, whereas plasma renin activity increased from 0.6 +/- 0.2 to 4.4 +/- 1.1 ng/ml/hr (P less than 0.05). This was associated with increases in plasma potassium levels from 3.9 +/- 0.2 to 5.4 +/- 0.4 mEq/L (P less than 0.005) and a significant reduction in fractional excretion of potassium from an average of 34% to 25%. No significant changes in plasma creatinine levels were observed during therapy. There was a significant positive correlation between aldosterone excretion and the potassium excretion fraction (r = 0.53; P less than 0.01). Increases in plasma potassium levels were not able to increase aldosterone excretion, although the greater the plasma potassium level attained, the smaller the reduction in aldosterone excretion (r = 0.47; P less than 0.05). Our results indicate that adequate aldosterone production is essential to preserve potassium homeostasis in chronic renal failure. Moreover, angiotensin II appears necessary for an adequate aldosterone response to potassium stimulation.

Regression of left ventricular hypertrophy in the short-term treatment of hypertension with isradipine.

This was a study of the effectiveness of isradipine, a calcium antagonist of the dihydropyridine group, in reversing left ventricular hypertrophy (LVH) in patients with mild-to-moderate hypertension. Mean arterial pressure was effectively reduced at 90 days of treatment (from 129.5 +/- 2.0 to 111.5 +/- 2.8 mm Hg; P less than .001). The electrocardiographic Romhilt-Estes score for LVH showed early reduction at 45 days of treatment (from 7.1 +/- 0.6 to 5.1 +/- 0.4 points; P less than .001), and further diminutions were observed at 90 days of treatment (3.8 +/- 0.4 points; P less than .01). The echocardiographically determined left ventricular mass indices confirmed these findings (from 175.0 +/- 8.9 to 141.7 +/- 5.5 and to 124.8 +/- 4.2 g/m2; P less than .001) for 45 and 90 days, respectively. The results indicate that isradipine is effective in reducing left ventricular mass and that these reductions are observed early in the course of treatment.

Determination of erythrocyte uroporphyrinogen I synthetase activity in chronic renal failure.

To obtain some information on porphyrin metabolism in uraemic patients, the activity of erythrocyte uroporphyrinogen I synthetase was measured in patients with chronic renal failure. The results indicate a decreased enzymatic activity which is not due to urea interference, in the hemolysates of these patients.

Bone disease in calcium stone forming patients.

The association between idiopathic hypercalciuria and osteopenia (OP) has been recently recognized. It is not established whether or not calcium intake plays a critical role in the loss of bone mass. Fifty-five calcium stone forming patients with either absorptive hypercalciuria (AH) or fasting hypercalciuria (FH), 29 males and 26 premenopausal females, were submitted to dual photon absorptiometry at lumbar spine. Calcium intake was assessed by a 72 hr dietary record. OP was detected in 20% (11/55) of patients, being more common among men, 9/26 (35%) than in women, 2/29 (7%), p < 0.05. Male FH patients presented lower mean bone mineral density (BMD) than sex, weight and age-matched control (1.058 +/- 0.18 vs 1.209 +/- 0.13 g/cm2, X +/- SD, p < 0.05). OP was more frequent in FH patients, 7/20 (35%) than in AH patients 4/35 (11%), albeit the difference was not statistically significant. There was no correlation between calcium intake and BMD measurement. Six osteopenic male FH patients were further submitted to histomorphometric evaluation with tetracycline double labeling. Bone volume was lower than the controls (13.2 +/- 3.0 vs 27.2 +/- 3.7%, p < 0.05). Osteoid surfaces were reduced, although not significantly (10.1 +/- 8.2% vs 15.9 +/- 6.7%). Eroded surfaces were markedly increased (23.9 +/- 13.4 vs 4.2 +/- 1.4%, p < 0.05). The bone formation rate was very low with a complete lack of tetracycline double labeling in 4 patients. These data suggest low bone volume, tendency to low bone formation, increased bone resorption and a severe mineralization defect, consistent with normal or low bone turnover osteoporosis.

Effect of sodium fusidate and ofloxacin on Staphylococcus aureus colonization and infection in patients on continuous ambulatory peritoneal dialysis.

The effectiveness of sodium fusidate and ofloxacin to eliminate nasal and catheter exit-site Staphylococcus aureus colonization and to prevent infections was compared in 31 patients on continuous ambulatory peritoneal dialysis (CAPD). In a prospective randomized study, 9 patients were treated with topical 2% sodium fusidate ointment applied in the anterior nares and in the pericatheter skin twice daily for 5 days; 9 subjects received oral ofloxacin 200 mg taken every 48 hours for 5 days and 13 subjects were in the control group. Treatment courses were repeated at one-month intervals. Mean duration of follow-up was 7.8 months (242 patients-month). Follow-up samples from the nares and the catheter exit-site were obtained every month from all participants to determine the presence of S. aureus. Development of S. aureus exit-site infection and peritonitis were assessed. During the study, S. aureus was recovered from 45%, 59% and 52% of the samples from the nares and/or exit-site in the sodium fusidate, ofloxacin and control groups, respectively (p = 0.13). S. aureus grew less frequently (p < 0.01) in samples from the exit-site in the sodium fusidate than in the other two groups. Eradication of nasal colonization (two negative cultures within one month) was observed in 43%, 40% and 33% of the cases in the sodium fusidate, ofloxacin and control groups, respectively (p > 0.50). The corresponding figures for exit-site eradication were 43%, 33% and 11%, respectively (p = 0.34). Twenty-four S. aureus-associated infection episodes (12 of exit-site and 12 of peritonitis) were diagnosed in 16 of the 31 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Late diagnosis of chronic renal failure and the quality of life during dialysis treatment.

We evaluated the quality of life of 101 hemodialysis patients who had a late < or = 3 months before starting dialysis, N = 47) or early (> or = 6 months, N = 54) diagnosis of chronic renal failure. At the time of the survey patients had been stable on dialysis for at least 3 months and for less than 24 months; median duration of dialysis was 9.1 months. Quality of life was measured by the kidney disease questionnaire (including the intensity and duration of physical symptoms, fatigue, depression, relationship with others and frustration), the health and life satisfaction indices, functional status (Karnofsky scale), and the time trade-off method. Scores for the several indicators of quality of life were closely similar for the late and early diagnosis groups. Health satisfaction compared to one year prior to dialysis was slightly better for the early diagnosis group. For both groups, functional status was a little worse during the first year of dialysis than one year before its start. In the late diagnosis group, elderly patients and diabetics had more impairment in several dimensions assessed. In addition, in this group greater income was significantly correlated with better physical performance (r = 0.52, P < 0.001) and with health satisfaction (r = 0.36, P = 0.027). These findings suggest that after a median duration of 9 months on a dialysis program, patients with a late and early diagnosis of chronic renal failure have a similar performance in terms of quality of life parameters. Age, diabetes and income are associated with the quality of life of patients with a late diagnosis.

Late diagnosis of chronic renal failure.

A comparison was made between patients with a late diagnosis of chronic renal failure (1 month or less before starting dialysis, N = 96) and those with an early diagnosis (6 months or more, N = 45) in terms of the following aspects: referral characteristics during the pre-dialysis phase, demographic details and patient biochemistry prior to maintenance dialysis. Information was obtained by surveying consecutive patients with primary renal disease admitted to a university dialysis unit in São Paulo. Fifty-three percent of all patients surveyed had a late diagnosis. These patients had a lower median duration of symptoms (2 vs 6 months, P < 0.01) and were less likely to be referred for dialysis by a nephrologist (9% vs 51%, P < 0.001) than early diagnosis patients. In the early diagnosis group, 7 patients (16%) had follow-up care for less than 6 months and 11 (24%) did not receive any follow-up; 21 patients (47%) did not follow a low-protein diet. At the start of dialysis, patients with a late diagnosis had higher blood pressure and a higher rate of pulmonary infections (19% vs 4%, P = 0.03). Mean concentrations of BUN, serum creatinine and potassium were significantly higher and mean blood hematocrit was lower for the late diagnosis group. After 3 months of dialysis, the mortality rate was higher in the late than in the early diagnosis group (22.9% vs 6.7%, P = 0.02). Late diagnosis of chronic renal failure and lack of adequate follow-up care, prior to the start of dialysis, are common. Interventions to promote early diagnosis of chronic renal failure and to improve compliance with regular nephrological follow-up can be important to reduce the morbidity and the mortality of patients with chronic renal insufficiency.

Assessment of glomerular filtration rate utilizing subcutaneously injected 51Cr-EDTA.

1. 51Cr-EDTA injected with lidocaine and epinephrine, as a subcutaneous button, is slowly absorbed, and a plasma level that is relatively stable can be maintained for a time sufficient to permit measurement of the renal clearance of EDTA, which is a measure of glomerular filtration rate (GFR). We studied this procedure in 32 normal volunteers and 24 patients with different glomerulopathies, comparing EDTA and creatinine clearances. In 20 patients these measurements were also compared with inulin clearance. 2. Creatinine clearance overestimates GFR due to tubular secretion of creatinine. This secretion is present even in patients with significantly reduced glomerular filtration rates. As a consequence, the lower the GFR the higher the overestimation will be. 3. A good correlation was obtained between the 51Cr-EDTA and inulin clearance: y(EDTA) = 4.21 + 0.88 x (inulin), r = 0.98. The procedure is simple to perform, and the radiotracer utilized is significantly less expensive than iothalamate.

Properties of the isolated rabbit proximal convoluted tubule and pars recta after long-term storage in a modified Collins solution.

The effect of storage of cortical slices in modified Collins solution on the viability of rabbit proximal convoluted tubules (PCT) and pars recta (PR) was evaluated by microperfusion of isolated tubules in vitro. Cortical slices of rabbit kidney were stored for 1, 24, 48, 72 and 97 h at 4 degrees C in modified Collins solution. PCT and PR were dissected from these slices and perfused with a modified Krebs-Henseleit solution in vitro. Fluid absorption (JV) was 1.21 +/- 0.3 nl min-1 mm-1 (N = 8) and the transepithelial potential difference (PD) was -2.3 +/- 0.3 mV (N = 6) for PCT from cortical slices stored 0 to 3 h. JV was 1.01 +/- 0.09 nl min-1 mm-1 (N = 8) and PD was -1.9 +/- 0.6 mV (N = 5) for PCT from tissue stored 23 to 97 h. JV of PR from tissue stored 5 to 26 h was 0.75 +/- 0.1 nl min-1 mm-1 (N = 5) and PD was -1.5 +/- 0.3 mV (N = 5). JV was 0.76 +/- 0.1 nl min-1 mm-1 (N = 3) for PR stored 72 to 74 h, and PD was not measured. There was no correlation between storage time and JV or PD. Furthermore, the JV and PD values for these tubules were similar to those obtained for freshly dissected tubules. These results show that the isolated tubule preparation is useful for the direct assessment of the efficacy of different kidney preservation solutions on nephron function.

Pulmonary gas exchange and ventilation during hemodialysis.

Hemodialysis-induced hypoxemia has been explained by several mechanisms: pulmonary microembolization, decreased pulmonary diffusing capacity, fall in alveolar oxygen tension, hypoventilation and ventilation/perfusion abnormalities. The objective of this study was to analyze the factors influencing pulmonary ventilation and gas exchange of 20 patients with chronic renal failure during hemodialysis performed under the following conditions: Group 1 (9 patients) dialyzed against an acetate dialysate with a cuprophan membrane; Group 2 (7 patients) dialyzed against acetate bubbled with CO2 with a cuprophan membrane; Group 3 (4 patients) similar to Group 1, but using a polyacrylonitrile membrane. Arterial and venous blood samples were obtained from the respective lines during the predialysis period (zero), at 30, 60, 120 180 and 240 min of hemodialysis, and 60 min post dialysis (300 min) for the measurement of pH, PCO2, PO2, HCO-3 and total CO2. The minute expired volume (VE), expired fractions of O2 (FEO2) and CO2 (FECO2), O2 consumption (VO2), CO2 elimination through the lungs (VCO2) and dialyzer, respiratory exchange ratio (R), dead space to tidal volume ratio (VD/VT), alveolar ventilation (VA) and alveolar-arterial O2 difference (delta AaPO2) were measured and a leukocyte count was performed for each period of hemodialysis. The patients in Groups 1 and 3 showed a significant drop in ventilation and PaO2, a slight decrease in PAO2 and a significant increase in delta AaPO2. The patients in Groups 1 and 2 showed a significant leukopenia at 30 min of hemodialysis. The volume of CO2 eliminated across the dialyzer was very similar for the three groups of patients. Group 2 did not show any drop in ventilation or PaO2. For Group 2 venous line pH was very low and PCO2 was within the normal range, in contrast to the normal or high pH and low PCO2 shown by Groups 1 and 3. This study indicates that the drop in PaO2 was partially the consequence of a slight decrease in PAO2, but mainly due to the increase in delta AaPO2. Thus the most likely cause of the decrease in PaO2 was the VA/Q imbalance brought about by a drop in ventilation. The drop in ventilation was linked not only to the volume of CO2 eliminated across the dialyzer, but also to the amount of CO2 delivered to the lungs, and to the pH and PCO2 of the venous line.

Role of the prostaglandin and kallikrein-kinin systems in aminoglycoside-induced acute renal failure.

The role of humoral factors in the pathogenesis of gentamicin and tobramycin aminoglycoside-induced acute renal failure was studied in rats. Renal function was evaluated after inhibition of prostaglandin synthesis with indomethacin and inhibition of the kallikrein-kinin system with aprotinin. Plasma and urinary kallikrein levels were measured in aminoglycoside-treated rats, as was in vitro effect of of these antibiotics on plasma kallikrein activity and prekallikrein activation by dextran sulfate. Indomethacin treatment (2 mg kg-1 day-1, ip, for 13 days) of rats which received gentamicin or tobramycin (40 mg kg-1 day-1, ip, for 10 days) caused a further fall in glomerular filtration rate (GFR) and renal blood flow and an impressive increase in renal resistance. The effect of indomethacin on GFR was more evident for gentamicin- than tobramycin-treated animals. Aprotinin administration had no additional effects on the renal function of antibiotic-treated rats. Plasma and urinary kallikrein levels in aminoglycoside-treated rats were significantly lower than in untreated controls. Both aminoglycosides at concentrations of 0.1 mg/ml inhibited dextran sulfate activation of plasma prekallikrein, and 2.0 micrograms/ml tobramycin, but not gentamicin, inhibited the hydrolysis of H-D-Pro-Phe-Arg-p-nitroanilide by rat plasma. These data suggest that prostaglandins may protect against aminoglycoside nephrotoxicity.

Glomerular hemodynamics during abortion induced by RU 486 and sepsis in rats.

1. Acute renal failure is a very common consequence of septic abortion. Whole kidney and glomerular hemodynamics were evaluated in virgin (V), pregnant (PREG) and aborted (ABOR) euvolemic Munich-Wistar rats before and after E. coli (0111-B4) endotoxin (LPS) infusion in order to evaluate the effect of septic abortion on the renal microcirculation. 2. Abortion induced by RU 486 blunted the increase in glomerular filtration rate (GFR) induced by normal pregnancy (0.86 +/- 0.03 vs 0.63 +/- 0.07 ml/min, P < 0.05). In virgin rats, RU 486 did not modify the parameters of renal function. Significant alterations occurred in whole kidney and single nephron function. However, the changes in whole kidney function in the ABOR group were significantly higher than those observed for the V group (reductions in GFR were 42% in V and 80% in ABOR, RPF decreased 34% in V and 76% in ABOR, TRVR increased 82% in V and 400% in ABOR). 3. Mean single nephron glomerular filtration rate (SNGFR) was reduced in all groups after LPS (44% in V, 43% in V+RU, 55% in PREG, 60% in ABOR), due to significant decreases in glomerular plasma flow rate, QA (42% in V, 55% in V+RU, 53% in PREG, 57% in ABOR) and in glomerular ultrafiltration coefficient, Kf (46% in V, 47% in V+RU, 45% in PREG, 67% in ABOR). 4. These data show that LPS induced significant alterations in renal function in all groups. However, aborted rats were more sensitive to the effects of LPS than V rats. These results indicate that abortion may potentiate the effects of endotoxemia on renal function elevating the extent of acute renal failure and thus the mortality rate.

Specific and nonspecific aspects of humoral immune response in leprosy.

1. We have studied some generic and specific aspects of the humoral immune response in 96 patients with leprosy (29 paucibacillary and 67 multibacillary individuals). We determined serum immunoglobulins (IgM, IgG and IgA), CH50, C1q, C3 and C4, circulating immune complexes (CIC), C-reactive protein (CRP), rheumatoid factor (RF) and antinuclear antibodies. No specific pattern of general humoral immune changes could be observed. 2. The specific immune response was studied by the detection of specific IgM anti-M. leprae antibodies. An immunoradiometric assay (IRMA) and an ELISA were compared for clinical effectiveness. IRMA showed greater sensitivity for the serodiagnosis of leprosy as compared to ELISA (88.1% vs 58.2% for multibacillary patients and 20.7% vs 10.3% for paucibacillary leprosy patients). Specificity was 96% for IRMA and 97% for ELISA. 3. Our results indicate that nonspecific changes in the humoral immune response are of little value in assessing leprosy patients and that immune assays for the detection of specific anti-M. leprae antibodies may be of value in the diagnosis, study and follow-up of these patients.

Effect of positive pressure breathing on plasma antidiuretic hormone and renal function in dogs.

The effect of intermittent mechanical ventilation and positive end-expiratory pressure on plasma antidiuretic hormone concentration was determined in 14 pentobarbital anesthetized dogs. The study was divided into a control period (spontaneous respiration), and two consecutive 30 and 60 min periods after the start of controlled respiration: Group I - intermittent positive breathing (IPPB); Group II - positive end-expiratory pressure (PEEP) with 5 cm H2O. A decrease in urinary flow (36.9%) was observed during end-expiratory pressure breathing. An increase in plasma antidiuretic hormone in group II from 4.5 +/- 2.4 to 24.6 +/- 16.0 pg/ml (P less than 0.01) was associated with a significant reduction of free water clearance from 1.2 +/- 0.6 to 0.3 +/- 0.4 ml/min and an increase of the urine/plasma osmolality ratio (143%, P less than 0.05). The decrease in urinary output and concurrent reduction of urinary sodium excretion also suggest an influence of the fall in glomerular filtration rate and renal plasma flow on renal function. IPPB only reduced total Na+ and K+ excretion. These results indicate that the mechanisms underlying the renal response to positive end-expiratory pressure breathing may be due to an increase in antidiuretic hormone plasma levels leading to a fall in urinary flow and in part to a decrease in sodium excretion.

Metabolic factors for urolithiasis in acromegalic patients.

1. Acromegaly is associated with metabolic disturbances of calcium and phosphorus which can also contribute to renal lithogenesis. 2. In order to characterize these disturbances more precisely, an oral calcium load test was performed on 14 active acromegalic patients. Serum and urinary levels of calcium, phosphorus, uric acid, creatinine and urinary cyclic AMP were determined. 3. Of the 14 patients, 5 (36%) presented hypercalciuria, 5 (36%) presented intestinal calcium hyperabsorption, and 6 (43%) had uric acid hyperexcretion. Two patients (14%) presented nephrolithiasis. 4. The medical records of 32 additional acromegalic patients with or without active disease were reviewed for a history of previous stones, which was observed in three cases (9.5%). 5. The present data suggest that nephrolithiasis occurs more frequently among acromegalic patients because of the underlying metabolic disturbances of calcium presented by this population.

Idiopathic focal segmental glomerulosclerosis and HLA antigens.

The objective of the present study was to investigate a possible association between HLA class II antigens and idiopathic focal segmental glomerulosclerosis (FSGS). HLA-A, -B, -DR and -DQ antigens were determined in 19 Brazilian patients (16 white subjects and three subjects of Japanese origin) with biopsy-proven FSGS. Comparison of the HLA antigen frequencies between white patients and white local controls showed a significant increase in HLA-DR4 frequency among FSGS patients (37.7 vs 17.2%, P < 0.05). In addition, the three patients of Japanese extraction, not included in the statistical analysis, also presented HLA-DR4. In conclusion, our data confirm the association of FSGS with HLA-DR4 previously reported by others, thus providing further evidence for a role of genes of the HLA complex in the susceptibility to this disease.

Dietary habits of calcium stone formers.

1. Since dietary factors are known to be related to nephrolithiasis, calcium stone-forming (CSF) patients were evaluated in terms of calcium, total protein of both animal and plant origin, carbohydrate and energy intakes, on the basis of 72-h dietary records during the week plus 24-h dietary records during the week-end. 2. The data for 77 calcium stone formers (57 with absorptive hypercalciuria and 20 with renal hypercalciuria) were compared to those for 29 age-matched healthy subjects. The body mass index of the CSF group was higher than that of healthy subjects (P < 0.05). Consumption of all nutrients was similar for both groups during the week but week-end dietary records for CSF showed higher calcium intake (586 +/- 38 vs 438 +/- 82 mg/day, P < 0.05), protein to body weight ratio (1.2 +/- 0.1 vs 1.0 +/- 0.5 g kg-1 day-1, P < 0.05) and animal protein (56 +/- 3 vs 40 +/- 3 g/day, P < 0.05) when compared with healthy subjects. 3. Comparison of hypercalciuria subtypes (renal hypercalciuria and absorptive hypercalciuria) did not indicate any difference in calcium or energy intake between groups, either during the week or during the week-end. However, the absorptive hypercalciuric group presented higher protein and animal protein consumption during the week-end. 4. These data suggest a low calcium intake in this population, even by stone formers. The higher animal protein consumption by our calcium stone formers observed during week-ends seems to be more important than calcium intake for stone formation.

Characteristics of spontaneously hypertensive, Wistar Kyoto and Munich Wistar rats bred in Brazil.

The breeding of imported strains of isogenic rats was started in 1981 because of the lack of experimental rat models in Brazil. The imported strains were: Spontaneously Hypertensive Rats (SHR) and their normotensive controls Wistar Kyoto Rats (WKY) from the National Institutes of Health, Bethesda, MD, and Munich Wistar (MW) rats which present superficial renal glomeruli, from Simonsen Laboratories, Gilroy, CA. Breeding of these strains was carried out without strict barriers (conventional breeding), under Standard Operating Procedures and strict inbreeding. Environmental factors such as ration, light, temperature, type of shavings and bedding, size of cages and their population were constant. Body weight growth curves were constructed for the three strains. The productivity of imported rats and local breeding colonies in 1981, 1982 and 1983 was compared on the basis of the following parameters: mean litter size, productivity of the females, pre- and post-weaning mortality, and effective yield. Systolic blood pressure was also measured for SHR and WKY rats. MW rats showed a high and relatively stable reproduction performance. The productivity of SHR and especially WKY animals declined progressively during the first three years, making the breeding of these strains of isogenic rats very difficult.

Risk factors for the occurrence of cardiac arrhythmias in patients on continuous ambulatory peritoneal dialysis.

In order to evaluate the risk factors for the occurrence of ventricular arrhythmias (VA) in continuous ambulatory peritoneal dialysis (CAPD), we studied 47 patients by echocardiography, dipyridamole-thallium tests, and biochemical profile. We observed that the group with VA had a greater cardiac mass index dependent only on an increased left ventricular internal diameter. Septum and posterior wall thickness, as well as biochemical variables, were not associated with the presence of VA in CAPD patients. In addition, altered myocardial perfusion was not associated with VA in these patients.