P. L. Oe

Measurement of transcellular fluid shift during haemodialysis

A method is presented to measure transcellular fluid shifts during haemodialysis based on a simplified model of the electrical admittance of biological tissues. It allows for the measurement of intracellular and extracellular conductivities and their ratios. The method is noninvasive, clean and harmless, and can be easily computerised in order to be performed continuously. A typical example is given of a recording during haemodialysis.

Dialysis fluids and local host resistance in patients on continuous ambulatory peritoneal dialysis

The ability of polymorphonuclear leukocytes, monocytes and peritoneal macrophages to mount a respiratory burst in continuous ambulatory peritoneal dialysis (CAPD) fluids was tested in a phorbolmyristate acetate stimulated chemiluminescence assay. Fresh CAPD fluids depressed the chemiluminescence response of all three types of phagocytes tested to less than 18% of their chemiluminescence response in control buffer. When tested in spent CAPD fluids the suppression of chemiluminescence was 30–32%. Oxygen consumption of polymorphonuclear leukocytes was depressed in fresh CAPD fluids to below 40%. Both phagocytosis ofEscherichia coli by and bactericidal capacity of polymorphonuclear leukocytes and monocytes were suppressed in fresh CAPD fluids but not in spent effluents. The influence of acidic pH and hyperosmolality on phagocytic functions were studied separately by modifying the acidity or the glucose content of the control buffer. pH values below 6.0 significantly inhibited chemiluminescence but not phagocytosis. Under hypertonic conditions, both phagocytosis and chemiluminescence were inhibited. We conclude that the currently available CAPD solutions are beyond the limits of acid and osmotic tolerance of human phagocytic cells, and may thus compromise the peritoneal defenses of CAPD patients.

DETECTION OF HYDRATION STATUS BY TOTAL BODY BIOELECTRICAL IMPEDANCE ANALYSIS (BIA) IN PATIENTS ON HEMODIALYSIS

The purpose of the present study was to investigate whether total body bioelectrical impedance analysis (BIA) could be appropriate to assess normohydration (i.e. dry weight) in hemodialysis patients. This study is warranted, because the simultaneous assessment of both hydration and nutritional status by BIA requires the presence of a situation of normohydration in order to guarantee valid conclusions about the nutritional analysis. Segmental bioelectrical impedance was performed to classify patients according to their hydration status. BIA measurements revealed significant differences in TBW, ECW and ICW/ECW between three hydration subgroups (under-, normo-, and overhydration), whereas ICW was similar. Therefore, TBW, ECW and ICW/ECW appear appropriate variables to assess hydration status in patients on hemodialysis. Hemodialysis diminished ECW significantly, whereas ICW did not change, suggesting that a decrease of ECW explains the fluid loss during hemodialysis.

CAPD, a Permanent State of Peritonitis: A Study on Peroxidase Activity

In vivo in the animal model peritoneal macrophages can be divided by their peroxidase activity (PA) pattern in exudate-, exudate-resident-, resident- and PA-negative macrophages. In the normal steady state 90% of the macrophages are resident cells. After acute inflammation, exudate and exudate-resident macrophages appear, whereas after chronic inflammation exudate and PA-negative macrophages appear. CAPD patients with clear peritoneal effluent were studied because they are considered to be in a normal steady state. However, in only one of six patients resident macrophages were found. Exudate and PA-negative macrophages were always found, suggesting that in otherwise asymptomatic CAPD chronic inflammation exists. The clinical significance of the presence of resident macrophages is discussed.

Effect of changes in daily protein intake on renal function in chronic renal insufficiency : differences in reaction according to disease entity

Protein restriction is advocated in patients with chronic renal insufficiency (CRI) in an attempt to slow down further renal function deterioration, with the most obvious effect in patients with chronic glomerulonephritis (GN) and diabetic nephropathy, and much less in other disease entities, such as adult polycystic kidney disease (APKD), tubulointerstitial nephritis (TIN) and nephrosclerosis (NS). The mechanism by which protein restriction slows down the progression of renal failure remains unclear. Decline of hyperfiltration has been implicated. Whether long-term protein restriction in patients with CRI is associated with a decrease in hyperfiltration is not clear. We studied the effects of prolonged protein intake variation (isocaloric diets in 4-week periods of low (goal: 30-40 g protein daily) and high protein intake (goal: 80-90 g daily) on renal function in 51 patients with CRI. Patients were divided into subgroups according to the underlying renal disease (GN, n = 17; APKD, n = 9; TIN, n = 12; NS, n = 13). Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured at the end of each study period. Overall, GFR rose from 39 (9-90) to 46 (9-100) ml/min/1.73 m2 (median and ranges, p < 0.01), and ERPF from 158 (39-558) to 171 (32-676) ml/min/1.73 m2 (p < 0.01). GFR rose significantly in GN (15%, range -23 to 51%), APKD (5%, range -10 to 33%), and NS (8%, range -8 to 25%). ERPF only rose significantly in GN (14%, range -45 to 47%) and APKD (9%, range -9 to 25%).(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of trimazosin and its effects on blood pressure, renal function and proteinuria during short-term therapy of patients with impaired renal function and hypertension

SummaryThe kinetics and short-term (10 weeks) effects of trimazosin, an alpha1-adrenoreceptor antagonist, on renal function and blood pressure in patients with moderate chronic renal insufficiency and hypertension, have been studied for the first time. Eight patients in whom the blood pressure was not normalized with a diuretic alone underwent pharmacokinetic studies and assessment of the renal function during a 10-week period of trimazosin therapy. Trimazosin significantly lowered blood pressure (recumbent and upright) without significantly altering renal function. Renal vascular resistance was decreased by 14%. Fractional sodium excretion, proteinuria and laboratory serum tests remained unchanged. Neither body weight nor pulse rate were affected. Moderate renal insufficiency did not modify the pharmacokinetics of the drug. Thus, trimazosin, as second-step antihypertensive agent, appeared to be safe and effective in patients with moderate renal insufficiency and hypertension, without exerting favourable or adverse renal effects during short-term therapy.

Survival and Growth of Staphylococcus epidermidis within Phagocytes in Relation to Recurrent Peritonitis in Continuous Ambulatory Peritoneal Dialysis Patients

Staphylococcus epidermidis is the most prevalent pathogen in continuous ambulatory peritoneal dialysis (CAPD) peritonitis.(1, 2) Peritonitis episodes recur or relapse in up to 36% of cases.(2–4) and a considerable proportion of the recurrent peritonitis episodes is seen in patients infected with either Staph. epidermidis or Staph. aureus. Little is known about the pathogenetic mechanisms that lead to the recurrence of peritonitis.

New Strategies Enhance the Role of Peritoneal Dialysis in Renal Replacement Therapy

Reviewing data from the European Dialysis Transplantation Association Registry for the past years reveals a steady growth in the demand for renal replacement therapy despite an increase in the number of patients undergoing renal transplantation. In the past decade continuous ambulatory peritoneal dialysis (CAPD) has increasingly been applied as an alternative to extend dialysis facilities. However, peritonitis continues to be the major complication of peritoneal dialysis, resulting in relatively high morbidity and drop-out rates ([1]). In our centre infectious complications were the major impediments to the growth of CAPD (fig. 1). After 5 years of CAPD, only 33 % of the patients trained was actually treated with CAPD. Therefore, modifications of standard CAPD i.e. CAPD with Y-connector and continuous cyclic peritoneal dialysis (CCPD), both reported be accompanied with remarkably lower peritonitis rates ([2], [3]), were introduced. Retrospectively, we compared drop-out rate from standard CAPD with that from its modifications.

A Chemoattractant in Peritoneal Effluent from Continuous Ambulatory Peritoneal Dialysis Patients

Continuous ambulatory peritoneal dialysis (CAPD) is an alternate treatment for chronic uremic patients. However, bacterial peritonitis is a serious complication that occurs in a relatively high number of CAPD patients(1, 2) It is generally accepted that phagocytic peritoneal cells (PC) determine the local defense in the peritoneal cavity. Therefore we investigated the Chemotaxis of PC from CAPD patients in response to the synthetic chemoattractant N- formylmethionyl-leucyl-phenylalanine (FMLP) and to their own peritoneal effluent (PE). In addition, high-pressure liquid chromatography (HPLC)-fractionated PE were tested for Chemotaxis to determine the molecular weight of the chemoattractant in the PE.

New Evidence for the Neurotoxicity of PTH in Uremia

Peripheral neuropathy is recognised as a complication of uremia in 60–65 % of the patients. There is still much discussion about its pathophysiology and the best way to diagnose it. As neurotoxic agents myoinositol, middle molecules and parathyroid hormone (PTH) were mentioned. Regarding diagnosis, no relation could be found between the peripheral nerve conduction velocity and the prevalence and severity of clinical neuropathy (1). It has been shown that H-M interval (late response) can be delayed while motor and sensory nerve conduction velocities are normal (2). The H-M interval has a very narrow normal range and is easy to obtain.