Reversible leukoencephalopathy syndrome associated to leukopenia in a chronic hemodialysis patient

Reversible leukoencephalopathy syndrome (RLS) is a rare brain disorder, characterized by diffuse attenuation of cerebral white matter, which has been most commonly observed in transplant patients receiving calcineurin inhibitors or in patients with severe hypertension. We report an episode of RLS in a 22-year-old male patient on chronic hemodialysis with well-controlled moderate hypertension who presented with de novo headache and generalized seizures. Cranial magnetic resonance image (MRI) revealed multiple areas of increased signal intensity in the white matter on T2-weighed images which resolved spontaneously at subsequent MRIs. White blood cell count showed leucopenia with normal CD4 count at flow cytometry. A viral etiology could not be demonstrated. Reversible leukoencephaolopathy syndrome symptoms remitted within 72 h but leukopenia persisted over 10 months. The patient received a kidney transplant 15 months after RLS onset and has received cyclosporine since the second post-transplant day. No recurrence of RLS symptoms has been observed. The etiology of the MRI changes in the present case seemed not to be either vasogenic or cytotoxic.     

Cerebrospinal fluid and plasma concentrations of proinflammatory mediators in human immunodeficiency virus-infected children

BACKGROUND: The pathogenesis of HIV encephalopathy is poorly understood especially in children. Studies suggest that HIV replication and the release of proinflammatory mediators in the central nervous system contribute to the pathogenesis of HIV dementia in adults. METHODS: Cerebrospinal fluid (CSF) and plasma samples from 23 HIV-infected children were longitudinally analyzed at Weeks 0, 8, 16 and 48 for HIV RNA and concentrations of the following proinflammatory mediators: monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha, regulated upon activation, normal T cell expressed and secreted (RANTES), macrophage-inflammatory protein (MIP)-1-alpha, MIP-1-beta and matrix metalloproteinase-9 (MMP-9). RESULTS: All 23 children had detectable concentrations of MCP-1 in the CSF at all time points evaluated. However, of the remaining of proinflammatory mediators measured in CSF at baseline, only a few children had detectable concentrations: tumor necrosis factor-alpha, n = 1; RANTES, n = 5; MMP-9, n = 9; MIP-1-alpha and MIP-1-beta, n = 0. A reduction from baseline to Week 48 was observed in CSF concentrations of MCP-1 and, among children with detectable values, MMP-9, which paralleled declines in CSF HIV RNA. CONCLUSION: These results suggest that MCP-1 and MMP-9 may be involved in the pathogenesis of central nervous system disease in HIV-infected children.     

Lucina's kidnap (or how to stop the cesarean section epidemic)

Cesarean sections rates have increased considerably in high- and middle-income countries in recent years. In Latin America the rates of surgical births reached 30% in Brazil, 40% in Chile, and 36% in Mexico. This essay describes the relationship of cesarean section with several mythological characters, presents a brief history of surgical births, and discusses the possible origin of its explosive increase. Among the factors associated to this epidemic we can mention economic incentives, a mounting supply of specialists, and the lack of comprehensive information on birth alternatives for pregnant women. The essay concludes with a call for a generalized control of this procedure based on evidence gathered through different kinds of interventions.     

Right versus left internal jugular vein catheterization for hemodialysis: complications and impact on ipsilateral access creation

This study investigated whether the anatomical differences between right and left internal jugular vein catheterization (RJVC and LJVC) would lead to differences in the frequency of complications, in particular, central vein occlusion (CVO). A group of 479 jugular vein catheterizations, 403 RJVC and 77 LJVC done in 294 prevalent hemodialysis patients were analyzed. A right-sided carotid pseudoaneurysm was the only major puncture-related complication. A total of 78 RJVC and 17 LJVC were inserted more than once in the same position. Of the RJVC, 44 (10.9%) of 403 were removed because of infection compared with 16 (20.8%) of 77 LJVC (P < 0.02). The overall incidence of infections was 1.58 episodes of infection per 1000 catheter days, 1.57 for RJVC and 3.72 for LJVC, respectively. Catheter dwell times were not different. A group of 127 patients with former RJVC and 44 with LJVC had ipsilateral arteriovenous access (RJVC+ and LJVC+ group, respectively). Four diabetic LJVC+ developed severe arm swelling secondary to CVO leading ultimately to access ligation. The RJVC+ group had no access ligated. LJVC may cause CVO in diabetics.     

Pharmacokinetic study of carbamazepine and its carbamazepine 10,11-epoxide metabolite in a group of female epileptic patients under chronic treatment

BACKGROUND: Although epileptic crises are equally frequent in women and men, several factors cause female epileptics to present a series of gender-specific problems. To date, few studies have been published on the kinetics of carbamazepine (CBZ) and carbamazepine 10,11-epoxide (CBZ-E) active metabolite in a Mexican population, and no information for epileptic women of reproductive age is available. The aim of the present work was to study the pharmacokinetic behavior of this group of women during steady state. METHODS: Fourteen epileptic women under chronic treatment receiving only the anticonvulsant CBZ to control their crises were studied. A blood sample was taken before breakfast, before the morning dose of 200 mg, and after the dose at 1, 2, 3, 4, 5, and 8 h. Serum was separated by centrifugation at 1,350 x g. Serum concentrations of carbamazepine (CBZ) and of the metabolite carbamazepine 10,11-epoxide (CBZ-E) were measured by HPLC. Pharmacokinetic parameters were calculated by statistical moment method after obtaining serum concentrations. RESULTS: Maximum time (T(max)) for CBZ was reached at 2.72+/-0.71 h and for CBZ-E, it was 3.60+/-0.79 h. C(max) for CBZ was 7.30+/-2.30 microg/mL, while C(min) for CBZ was 6.30+/-2.49. Maximum serum values for CBZ-E were 1.01+/-0.57, equivalent to 13.80% of CBZ; t(12) value for CBZ and CBZ-E was 18.20 and 16.10 h, respectively. AUC values for CBZ and metabolite were 70.33+/-17.10 microg/L/h and 9.20+/-2.50 microg/L/h, respectively. CBZ and CBZ-E clearance did not show differences and were 0.37 mL/kg/min and 0.40 mL/kg/min, respectively. Extraction index for serum concentrations of CBZ and CBZ-E AUC(CBZ)/AUC(CBZ-E) was 0.13; positive correlation was observed between serum concentrations of CBZ and E-CBZ, with r=0.94. CONCLUSIONS: The schedule we suggest for therapeutic monitoring of serum concentrations of CBZ in chronic treatments is 3 h for maximum peak concentration of C(max) after dose administration and for minimum peak concentration, C(min) prior to subsequent administration of the dose.     

Lack of technical specificity in the molecular diagnosis of toxoplasmosis

The polymerase chain reaction amplification of a fragment of the B1 gene of Toxoplasma gondii coupled to hybridization was performed in 42 patients from Rio de Janeiro, Brazil. The results showed 50% of positivity in the IgM positive toxoplasmosis group, and 12.5% in the positive IgG and negative IgM individuals. The data presented here revealed a lack of specificity of the molecular approach, clearly indicating that the primers used may co-amplify human sequences.