Circulating aggregated platelets, number of platelets per aggregate and platelet size in chronic dialysis patients.

The accelerated arteriosclerosis of chronic dialysis patients is multifactorial. Both non-uremic patients with atherosclerosis and uremic patients have functional platelet abnormalities. Our aim was to study platelet function in chronic dialysis patients and to correlate the findings with the presence of cardiovascular morbidity. Fifty-three chronic dialysis patients were examined. The presence of risk factors for cardiovascular disease (CVD) was recorded, and the patients were examined for the presence of ischemic heart disease, peripheral vascular disease and cerebrovascular accident. The parameters of platelet function, which were examined with the modified Wu and Hoak method, included platelet number, percentage of totally, reversibly and irreversibly aggregated platelets, average number of platelets per aggregate and percentage of large platelets. Significant differences were found between totally aggregated platelets, reversibly and irreversibly aggregated platelets, the percentage of large platelets (p < 0.0001) and the average number of platelets per aggregate (p < 0.001) in dialysis patients compared with control persons. There was no difference between the 2 groups in platelet count. No differences were found between hemodialysis and peritoneal dialysis groups, and the duration of dialysis treatment had no effect. We conclude that platelet abnormalities evident in chronic dialysis patients are a part of the multifactorial etiology of advanced CVD and may predispose dialysis patients to CVD.

Hospitalizations in dialysis end-stage renal failure patients.

The cost of treating end-stage renal failure (ESRF) patients includes not only the cost of dialysis and related medications but also the cost of hospitalizing these patients. This study examines the hospitalization rate in ESRF patients. During 1993, 126 ESRF patients were dialyzed in our institution. All hospitalizations were recorded. The study included 213 hospitalizations in 91 patients (mean 1.7 hospitalizations/patient/year). The mean length of each hospitalization was 4.8 +/- 5.6 days. Seventy-six hospitalizations were for 1 day. Access (vascular and peritoneal) was the main cause (31%), but these admissions accounted for only 8.7% of days in hospital, while cardiovascular and infections represented 38 and 29%, respectively. No correlation was found between type of dialysis, sex and erythropoietin use and hospitalization rate. 46.5% of admissions were uremia-dialysis related but they accounted for only 30% of the days in hospital. Age and the presence of diabetes mellitus correlated with hospitalization not related to uremia and/or dialysis. Thus, most of the time spent in hospital was secondary to conditions unrelated to uremia and/or dialysis. Efforts should be made to reduce the dialysis-uremia-related hospitalizations and thus reduce the cost of treatment.

Sweat electrolytes in patients with advanced renal failure.

The sweat gland has some similarity with the convoluted tubules of the kidney. Little is known about sweat secretion and electrolyte content of sweat in the uremic gland. A pilocarpine ionotophoresis sweat test was performed in 40 patients with advanced renal failure (RF). Sweat secretion was measured and analyzed for Na, K, and Cl and correlated to blood parameters, type, and duration of dialysis. The sweat weight was significantly lower in all RF patients when compared with this parameter in healthy controls (p < 0.0001). No difference was noted between patients undergoing hemodialysis, those undergoing continuous ambulatory peritoneal dialysis, and those not undergoing dialysis. Men sweated more than women among RF patients and among controls (p < 0.0001). An inverse correlation was found between sweat weight and blood calcium levels (p < 0.001). Sweat K concentration was significantly higher (p < 0.0001) in patients with RF than in healthy controls, while the concentrations of Na and Cl were similar. Several mechanisms are suggested as possible explanations for these changes.

Effects of residual renal function in haemodialysis patients.

Thirty-six haemodialysis patients on treatment for more than six months were studied for residual renal function (RRF). Twenty patients were anuric. The remaining 16 patients with RRF excreted 35-1600 ml urine/day with creatinine clearance ranging 0.17-6.95 ml/min. Patients with RRF were on dialysis therapy for shorter periods than those with anuria (25.5 +/- 18.5 vs. 101.7 +/- 14.2 months, p = 0.001). Twelve out of 20 anuric patients had had previous renal transplantation, whereas none of those with RRF had been transplanted (p = 0.0006). Interdialytic weight gain, serum potassium and phosphate were lower in patients with RRF. Serum phosphate and uric acid were correlated with their respective urinary excretion rates (p = 0.013 and 0.005, respectively), but interdialytic weight gain could not be correlated with urinary output. Creatinine clearance significantly correlated with urinary excretion of potassium, sodium, phosphate and uric acid. In this series of patients a previous unsuccessful renal transplantation was an important factor in the loss of RRF. The presence of RRF contributed to the regulation of the blood levels of phosphate and the excretion rate of potassium, sodium and uric acid.

Adequacy of dialysis and nutritional status in hemodialysis patients.

Twenty-three nondiabetic end-stage renal failure patients on hemodialysis were studied for adequacy of dialysis and nutritional status. Midweek predialysis blood urea nitrogen was 27.1 +/- 6.4 mmol/l of urea, KT/V, according to urea kinetic modelling, was 1.21 +/- 0.22 and mean normalized protein catabolic rate (nPCR) was 1.15 +/- 0.23 g/kg/day. Only 1 patient had a KT/V less than 1 and 4 patients had an nPCR less than 1 g/kg/day. No correlation was found between the different nutritional parameters. All patients had normal serum albumin. However, some of the patients could be classified as severely malnourished when parameters such as body weight (2 patients), triceps skinfold (5) and total lymphocyte count (3) were taken into account. No correlation was found between adequacy of dialysis and the different nutritional parameters. Furthermore, when patients were divided into low and normal KT/V, no differences were found in their nPCR. We conclude that a global assessment of the nutritional status is required in hemodialysis patients, and at least in patients with an acceptable KT/V, nPCR is not dependent on the adequacy of dialysis.

Skin surface pH, moisture, and pruritus in haemodialysis patients.

Pruritus is one of the most common complaints of haemodialysed patients. However, its pathogenesis remains unclear. Dryness of the skin and the effects of pH changes on the nerve endings in the skin have been suggested as related factors. In the present study we measured skin pH using a skin pH meter and skin moisture using a corneometer at four different sites in 41 haemodialysis patients, before and after dialysis, and in 40 healthy controls. Thirty patients (73%) complained of pruritus, six severe constant, 12 moderate and 12 mild. Skin surface pH was higher in patients than in controls in the upper back (5.54 +/- 0.14 versus 5.22 +/- 0.08, P < 0.02), forearm (5.5 +/- 0.1 versus 5.13 +/- 0.1, P < 0.01) and forehead (5.35 +/- 0.08 versus 5.04 +/- 0.07, P < 0.004), whereas there was no difference in the axilla. Haemodialysis had no effect on skin pH, and there was no correlation with blood pH, blood bicarbonate and serum electrolytes. There was no correlation between skin surface pH and pruritus. Skin moisture was lower in haemodialysis patients than in controls in the forehead and axilla. There was no correlation with pruritus. Skin surface pH is higher in haemodialysed patients than in healthy controls in most areas of the body, despite the fact that these patients have a decreased blood pH. Thus, the skin pH is not related to systemic acid-base balance. It is possible that the uraemic state affects the ability of the dermal cells to secrete acid, making the skin more susceptible to bacterial and fungal infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteremia complicating peritonitis in peritoneal dialysis patients.

Bacteremia is a rare complication of peritonitis in end-stage renal failure (ESRF) patients treated by peritoneal dialysis. Three of our ESRF patients on peritoneal dialysis developed bacteremia during a peritonitis episode (1/19 peritonitis episodes). In 2 cases, the responsible organism was Escherichia coli and peritonitis was most likely associated with infection of the biliary tract. The 3rd patient had a perforation of the colon and Klebsiella spp. was the infective organism. Only the last patient survived but had to be transferred to hemodialysis. Bacteremia during peritonitis is infrequent in peritoneal dialysis patients and it appears to be related to other intra-abdominal events.

Compliance in hemodialysis patients: a multivariate regression analysis.

Successful treatment of patients with end-stage renal failure requires, in addition to dialysis, strict control of dietary, fluid and medication intake. In the present study we measured, in 50 chronic hemodialysis patients, serum potassium (K), serum phosphate (PO4) and interdialytic weight gain as indices of diet, medication and fluid compliance, respectively. Dietary compliance did not correlate with fluid or medication compliance, whereas fluid intake and medication compliance were related (p = 0.01). Age, time on dialysis, place of birth and whether the patient came accompanied or not to the dialysis unit were the main variables affecting serum K levels. Sex, ethnic origin and education significantly affected serum PO4. Sex, place of birth, marital status, number of children and years of education affected fluid intake. The compliance of the hemodialysis patient with different aspects of his regimen is thus multifactorial. Attempts to improve compliance and thus reduce morbidity and mortality should be aimed at identifying the population with low compliance and exposing them to educational programs.

Prostanoids and thromboxane production by renal brush border membrane.

It has been estimated that proximal tubule are responsible for about 7.5% of total kidney prostaglandin PGE2 production. In the present report we investigated the production of prostanoids and thromboxane by rabbit renal proximal tubule brush border membrane. PGF2 alpha was the major endogenous prostaglandin produced under basal condition. The addition of exogenous arachidonic acid increased only PGE2 production. No PGE2 production was found when vesicles were incubated with indomethacin or at 4 degrees C, suggesting the involvement of the PGH2 synthase and PGE2 isomerase enzymes. Addition of angiotensin II at 10(-6) and 10(-9) mol l-1 did not affect the endogenous PGE2 production by brush border membrane. Thus, results of our study demonstrates that the renal proximal tubule brush border membrane has the capacity to produce prostanoids and thromboxane.

Causes of death in patients with end-stage renal disease treated by dialysis in a center in Israel.

The causes of death in 84 end-stage renal failure patients, treated with dialysis, who died during a 66-month period were reviewed retrospectively. Cardiac and infectious diseases were the main cause of death (27% each). These two constituted 44% of causes of death in hemodialysis and 75% in continuous ambulatory peritoneal dialysis patients. Malignant disease (7%) and hyperkalemia (5%) were responsible for death only in hemodialysis patients. Patients who died following hyperkalemia were younger than 50 years old. Patients who died from malignant disease were dialyzed for more than 3 years. In summary, the mode of dialysis therapy, age at start of therapy, time on dialysis, and previous cardiac disease may play a role in determining the causes of death in dialysis patients.

The autosomal dominant polycystic kidney disease gene in a Jewish family from Uzbekistan is PKD1.

A large Jewish family from Tashkent (Uzbekistan) was studied for linkage of autosomal dominant polycystic kidney disease (ADPKD) to molecular markers on the short arm of chromosome 16. A restriction fragment length polymorphism (RFLP) analysis was performed on 28 family members, including 9 ADPKD diagnosed patients in 3 consecutive generations. A specific haplotype was found to segregate with the disease in eight of the nine affected individuals. The peak lod scores for linkage between the disease phenotype and the five informative flanking markers were: 3'HVR 1.70 at theta = 0.08; GGG1 1.18 at theta = 0.001; CMM65 1.50 at theta = 0.001; 26-6 0.86 at theta = 0.001 and 218EP6 1.39 at theta = 0.001. A particular haplotype of these markers segregated with the disease phenotype. The peak lod score of this haplotype was 3.046. Homogeneity test, comparing this family to 40 PKD European families, showed that the conditional probability that it belongs to the same group is 1.000. Taken together, these findings show that the defective gene in this Jewish family from Uzbekistan is PKD1. To our knowledge, this is the first ADPKD family in Israel in whom linkage studies were performed and one of the few originating from populations outside the Western world.

CAPD versus haemodialysis: a comparison in the same patients.

Most studies comparing CAPD and haemodialysis (HD) were done in different populations, matched for sex and age. The present report compared 13 non-diabetic end-stage renal failure patients who were treated for at least six months with each type of therapy. Analysis of the data revealed a higher haemoglobin during CAPD but no differences in the blood transfusion requirements. Serum creatinine, BUN and potassium were lower during CAPD and serum calcium was higher during HD. Serum cholesterol levels were higher during CAPD and returned to pre-CAPD levels during the fourth month after being transferred to HD. Hospitalization rates were similar with the two treatments. Our study confirmed previous sex- and age-matched studies comparing CAPD and HD therapy.

Angiotensin II directly increases rabbit renal brush-border membrane sodium transport: presence of local signal transduction system.

In the present study, we have examined the direct actions of angiotensin II (AII) in rabbit renal brush border membrane (BBM) where binding sites for AII exist. Addition of AII (10(-11)-10(-7) M) was found to stimulate 22Na+ uptake by the isolated BBM vesicles directly. All did not affect the Na(+)-dependent BBM glucose uptake, and the effect of AII on BBM 22Na+ uptake was inhibited by amiloride, suggesting the involvement of Na+/H+ exchange mechanism. BBM proton permeability as assessed by acridine orange quenching was not affected by AII, indicating the direct effect of AII on Na+/H+ antiport system. In search of the signal transduction mechanism, it was found that AII activated BBM phospholipase A2 (PLA) and that BBM contains a 42-kDa guanine nucleotide-binding regulatory protein (G-protein) that underwent pertussis toxin (PTX)-catalyzed ADP-ribosylation. Addition of GTP potentiated, while GDP-beta S or PTX abolished, the effects of AII on BBM PLA and 22Na+ uptake, suggesting the involvement of G-protein in AII's actions. On the other hand, inhibition of PLA by mepacrine prevented AII's effect on BBM 22Na+ uptake, and activation of PLA by mellitin or addition of arachidonic acid similarly enhanced BBM 22Na+ uptake, suggesting the role of PLA activation in mediating AII's effect on BBM 22Na+ uptake. In summary, results of the present study show a direct stimulatory effect of AII on BBM Na+/H+ antiport system, and suggest the presence of a local signal transduction system involving G-protein mediated PLA activation.

Transfusion reactions due to bacterial contamination of blood and blood products.

Bacterial infections transmitted by blood or blood products, although rare, remain a serious threat to the recipient of a transfusion. We report on five cases of adverse reactions due to bacterial contamination of blood products, and we review 76 similar cases reported in the English-language literature. Most cases (70%) have been reported from the United States. Various sources of contamination have been suggested, including infection in the donor and invasion of the blood product during the process of collection, preparation, and storage. Frequent clinical manifestations are fever (80%), chills (53%), hypotension (37%), and nausea or vomiting (26%). The overall mortality is 35% (28 of 81 patients). In 38 patients (47%) the adverse reactions have appeared during transfusion; in the others the interval between completion of the transfusion and appearance of symptoms has ranged from 15 minutes to 17 days. A wide spectrum of bacteria have been implicated as causes of adverse reactions, with Pseudomonas species involved in 28% of episodes. Many such reactions are probably misdiagnosed or overlooked, the result being underestimation of the extent of the problem.

[Peritoneal equilibration test].

7 men and 3 women (mean age 62 +/- 11 years) with end-stage renal disease, who were on continuous ambulatory peritoneal dialysis, underwent a peritoneal equilibration test to determine the rate of peritoneal ultrafiltration and creatinine transfer. The test is based on glucose absorption into the plasma from the peritoneal solution and the diffusion of creatinine into the peritoneal fluid after 2-4 hours. Patients with rapid absorption of glucose have low drain water ultrafiltration volumes but higher creatinine clearances, and therefore need adjustment of the therapy plan or else should be on hemodialysis. No correlation was found between the time the patients were on treatment and glucose absorption or creatinine diffusion.

Increased Na+/H+ antiport activity in the renal brush border membrane of SHR.

Defect in renal salt excretion may play an important role in the pathogenesis of hypertension. We examined sodium (Na+) uptake by brush border membrane (BBM) vesicles of young (6 week old) spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) of the same age. SHR had lower urinary Na+ excretion (223.1 +/- 9.3 vs. 266.3 +/- 3.7 microEq/day/100 g, N = 8, P less than 0.01) and higher systolic blood pressure (98.9 +/- 1.2 vs. 82.9 +/- 1.8 mm Hg, N = 8, P less than 0.01) than WKY. BBM vesicle Na+ uptake, measured by rapid filtration technique, was higher in SHR when compared to WKY (1.44 +/- 0.03 vs. 1.01 +/- 0.06 nmol/mg/5 sec, N = 4, P less than 0.01). This increase in Na+ influx was apparent only in the present of an outward-directed proton (H+) gradient and was abolished by 1 mM amiloride. BBM permeability to H+ as assessed by acridine orange quenching was not different between SHR and WKY. Kinetic analyses of the amiloride-sensitive BBM Na+ uptake revealed a higher Vmax (2.13 +/- 0.27 vs. 0.70 +/- 0.30 nmol/mg/5 sec, N = 4, P less than 0.01) and a higher km for Na+ (3.55 +/- 0.32 vs. 1.23 +/- 0.14 mM, N = 4, P less than 0.05) in SHR. These findings thus demonstrate an intrinsic derangement in BBM Na+ transport in young SHR which is characterized by increased Na+/H+ antiport activity. This alteration in antiport activity is not attributable to changes in membrane permeability to H+, and is characterized by higher Vmax and km.(ABSTRACT TRUNCATED AT 250 WORDS)

Ca2+ dependency of Na+ transport by rabbit renal brush border membrane.

Intracellular Ca2+ has been suggested to play an important role in the regulation of epithelial Na+ transport. Previous studies showed that preincubation of toad urinary bladder, a tight epithelium, in Ca2+-free medium enhanced Na+ uptake by the subsequently isolated apical membrane vesicles, suggesting the downregulation of Na+ entry across the apical membrane by intracellular Ca2+. In the present study, we have examined the effect of Ca2+-free preincubation on apical membrane Na+ transport in a leaky epithelium, i.e., brush border membrane (BBM) of rabbit renal proximal tubule. In contrast to toad urinary bladder, it was found that BBM vesicles derived from proximal tubules incubated in 1 mM Ca2+ medium exhibited higher Na+ uptake than those derived from proximal tubules incubated in Ca2+-free EGTA medium. Such effect of Ca2+ in the preincubation medium was temperature dependent and could not be replaced by another divalent cation. Ba2+ (1 mM). Ca2+ in the preincubation medium did not affect Na+-dependent BBM glucose uptake, and its effect on BBM Na+ uptake was pH gradient dependent and amiloride (10(-3) M) sensitive, suggesting the involvement of Na+/H+ antiport system. Addition of verapamil (10(-4) M) to 1 mM Ca2+ preincubation medium abolished while ionomycin (10(-6) M) potentiated the effect of Ca2+ in the preincubation medium is likely to be mediated by Ca2+-dependent cellular pathways and not due to a direct effect of extracellular Ca2+ on BBM.(ABSTRACT TRUNCATED AT 250 WORDS)

Shigella bacteremia in adults. A report of five cases and review of the literature.

Shigella bacteremia is rare, occurring mainly in children. We describe five adult patients with Shigella bacteremia and review data on 22 cases reported in the English-language medical literature. Eighteen (67%) of 27 patients had either an underlying condition or were aged older than 65 years. Most patients had clinical signs of acute febrile gastroenteritis. However, in six patients, the organism was not isolated from stool. Species isolated from blood included Shigella flexneri in 11 patients, Shigella sonnei in eight, and Shigella boydii and Shigella dysenteriae in one patient each. Isolation of the bacterium from blood only was associated with a high mortality rate, in contrast to its isolation both from blood and stool. It is suggested that blood cultures should be obtained from elderly or immunocompromised patients with acute febrile gastroenteritis to detect shigellemia as well as bacteremia caused by other enteric pathogens, such as Salmonella or Campylobacter.

Infected renal hematoma complicating anticoagulant therapy.

We describe a case of spontaneous infection of a renal hematoma complicating warfarin sodium anticoagulant therapy. The infected hematoma was successfully drained by sonar-guided fine-needle aspiration. All reported cases of renal hematomas complicating anticoagulant therapy are reviewed.