[Kinetics of potassium transfer during hemodialysis]. / Cinétique des transferts de potassium en cours d'hémodialyse.

INTRODUCTION: In order to study whether the removal of potassium in haemodialysis patients could be increased, we analyzed the kinetics of potassium transfer in the dialyzer. METHOD: 40 patients were included in the study. We studied: a) in vitro potassium exchanges between erythrocytes and plasma; b) plasma and erythrocyte potassium concentrations at dialyzer input and output; c) potassium transfers into the dialysate, using plasma clearance and direct measurement in the collected dialysate and d) erythrocyte potassium concentrations at the beginning and the end of dialysis. RESULTS: In vitro, there is virtually no potassium transfer between erythrocytes and plasma. In vivo, erythrocyte potassium concentration is not affected by the dialyzer (98.7 +/- 6.4 mmol/l to 97.7 +/- 7.5 mmol/l, p = NS). Potassium transfer levels determined by calculated plasma clearance were similar to values obtained by measuring potassium in dialysate (0.71 +/- 0.10 mmol/min vs 0.68 +/- 0.10 mmol/min, p = NS). These results suggest that erythrocytes do not participate in potassium exchange in the dialyzer. This was confirmed by measured erythrocyte potassium concentrations, which were the same at the beginning and the end of dialysis (104.0 +/- 5.6 mmol/l vs 104.2 +/- 5.0 mmol/l, p = NS).

JC virus genotypes in France: molecular epidemiology and potential significance for progressive multifocal leukoencephalopathy.

JC virus (JCV) induces progressive multifocal leukoencephalopathy (PML), especially in human immunodeficiency virus (HIV)-infected patients. Although JCV genotypes have primarily been associated with geographic patterns, a distinctive neuropathogenicity was recently attributed to genotype 2. A multicenter study was conducted to describe the distribution of JCV genotypes in France and to investigate correlations between genotypes and PML. Genotypes were determined by sequencing 494 bp in the VP1 capsid gene. Peripheral JCV was studied in 65 urine samples from 43 HIV-infected patients and from 22 control subjects. Genotypes 1, 4, 2, and 3 were detected in 52.3%, 30.8%, 12.3%, and 4.6% of the samples, respectively. In 56 brain or cerebrospinal fluid samples, PML-associated JCV of genotypes 1, 2, 4, and 3 was found in 66%, 19.7%, 8.9%, and 5.4%, respectively. Infection with JCV genotypes 1 or 2 was correlated with PML (odds ratio, 3.29). On the other hand, infection with JCV genotype 4 could represent a lower risk for PML.

Prevalence of JC virus viraemia in HIV-infected patients with or without neurological disorders: a prospective study.

Progressive Multifocal Leukoencephalopathy (PML) is a severe demyelinating disease, which is rapidly fatal and is due to JC virus (JCV) infection, which especially occurs in HIV-infected patients. To investigate JCV pathophysiology and to evaluate the predictive value of JCV detection in blood, we looked for JCV DNA in leukocytes and plasma of 96 patients without any neurological symptoms and 109 patients with neurological diseases, among whom 19 were suffering from PML. JCV genome was detected in about 18% of all patients, i.e. 15.6% of patients with central nervous system disorders except PML, 13.5% of patients without neurological symptoms and significantly more often in PML patients (47.6%). Both leukocytes and plasma were tested; in plasma, JCV DNA was found in 36.1% of positive patients and in cells in 80.5%. Surprisingly in seven instances only the plasma contained JCV genome. One-year follow-up of these patients showed that the absence of JCV DNA in blood was associated with a very low probability of developing PML (negative predictive value=0.99).

Case report of bone mastocytosis: total hip arthroplasty for osteoarthritis and open reduction for condylar fracture of the knee.

A 72-year-old woman was admitted in 1984 for painful protrusive osteoarthritis of the left hip diagnosed as systemic mastocytosis with bone lesions and clinical features of intestinal malabsorption but no clinical skin lesion. The total hip replacement, refused in a first step because of the bone pathology, was carried out two years later. Signs of loosening appeared after one year. In 1990, following a traumatic bicondylar fracture of the left knee, an osteosynthesis was carried out. Ten days later, a shaft pathologic fracture of the femur above the osteosynthesis plate implied another open reduction. Two and a half years later, the patient is able to walk short distances, using walking sticks, and lives at home receiving social assistance.

Virological diagnosis of progressive multifocal leukoencephalopathy: detection of JC virus DNA in cerebrospinal fluid and brain tissue of AIDS patients.

Cerebrospinal fluid (CSF) from 12 AIDS patients with clinical signs consistent with progressive multifocal leukoencephalopathy (PML) was examined by the polymerase chain reaction (PCR) for the presence of JC virus (JCV). A specific JCV target sequence was amplified in the CSF from 9 of the 12 patients and also in brain tissue from all nine JCV-positive patients. The clinical course, neuroimaging features, and, in four cases, histopathology of brain tissue proved that the nine patients had PML. In the other three patients with central nervous system disorders, the JCV genome was undetectable by PCR and Southern blot analysis in CSF and brain tissue. The clinical course and neuroimaging features ruled out PML in these three patients. Five CSF samples and five brain tissue specimens from 10 PML-free AIDS patients with central nervous system disorders were all negative for the JCV genome by PCR and Southern blot analysis. These results show that detection of JCV in CSF by PCR is a good alternative to brain tissue studies for the virological diagnosis of PML in AIDS patients.

[Reversibility of IUdR resistance to sensitivity to an HSV1 strain in experimental keratitis in rabbits]. / Réversibilité de la résistance à l'IUdR vers la sensibilité d'une souche HSV1 au cours de la kératite du lapin.

During 7 serial passages of Herpes Simplex Virus (HSV1) in rabbit cornea treated with idoxuridine (IUdR) (P1 to P7), the emergence of resistance had been obtained from P3. The reversion towards IUdR sensitivity has been investigated from either viral population P3 or P6 by 6 serial passages in rabbit cornea treated by Vaseline (V1 to V6). From viral population P3, the reversion to IUdR sensitivity has been obtained at V4. In contrast, from viral population P6, the IUdR resistance was conserved from V1 to V6. In vitro, on Vero cells, the effective doses 50% (ED50) and 90% (ED90), determined by dye uptake assay and plaque reduction assay, confirmed the reversibility towards IUdR sensitivity obtained from P3 and the stability of IUdR resistance from P6.

[Rheumatoid arthritis: what do patients do with our prescriptions?]. / Polyarthrite rhumatoïde: que font les patients de nos prescriptions?

This study encompassing a sample of 103 out-patients with chronic polyarthritis revealed that only 71.6% of the patients showed good compliance with the prescribed medication. A relatively large cohort (61%) used paramedical treatments. Factors influencing compliance-behavior, in particular attitude to paramedical methods are investigated.