Increased red blood cell deformability due to isoxsuprine administration decreases platelet adherence in a perfusion chamber: a double-blind cross-over study in patients with intermittent claudication

Platelet transport towards the vessel wall is influenced by the hematocrit, red blood cell (RBC) size, and shape. Recent in vitro studies have indicated that RBC deformability may also influence platelet transport. The observation that isoxsuprine, a known vasodilating drug, caused increased RBC deformability in vitro and decreased platelet transport in vitro prompted us to study the effects of this drug in vivo. The study was performed in a double-blind cross- over study of isoxsuprine v placebo in ten patients with peripheral arterial insufficiency. RBC deformability was estimated from viscosity measurements using the blood viscosity equation of Dintenfass and expressed as T value. Platelet transport was studied in an annular perfusion chamber according to Baumgartner. Human umbilical arteries were used as blood vessels. Perfusion studies were performed with whole blood or with RBCs of the patients mixed with normal platelets and plasma at a standardized hematocrit and platelet count. An increase in RBC deformability concomitant with a decrease in platelet adherence was observed in patients on isoxsuprine with a drop in T value of approximately 0.06 (from 0.91 toward 0.86), and a concomitant decrease in platelet adherence of 20% to 40%. These observations differed significantly from the results in the placebo group and showed a significant group-period interaction at the cross-over of medication (analysis of variance). The effects on platelet adherence were observed at high vessel wall shear rate (1,800 s-1) with perfusates consisting of patients' RBCs and donor plasma and platelets at standardized hematocrit and platelet count. No differences were observed under these conditions at a shear rate of 300 s-1. When whole blood of patients was used, nonsignificant effect was observed at shear rates of 300 s-1 and 1,800 s-1. This was probably caused by the added noise due to variations in hematocrit and platelet number. These data demonstrate that isoxsuprine increases RBC deformability, and they suggest the possibility of decreasing platelet-vessel wall interaction in vivo by manipulation of RBC deformability.     

Immune complexes containing factor V in a patient with an acquired neutralizing antibody

An 82-year-old woman presented with extensive hematomas and melena associated with markedly decreased plasma factor V coagulant activity (FV:C). Using a competitive enzyme-linked immunosorbent assay developed in our laboratory, we made serial measurements of factor V antigen (FV:Ag) in plasma and found it to be normal or elevated. The patient's plasma was demonstrated to contain an IgG antibody that could neutralize FV:C in normal plasma. The antibody was of restricted heterogeneity (IgG1, IgG2,kappa). Circulating immune complexes containing antibody to factor V and FV:Ag were demonstrated directly in the plasma by immunoelectrophoresis with polyclonal monospecific antibody and with a monoclonal antibody using an enzyme-linked immunosorbent assay. Presence of neutralizing antibody could be demonstrated in vitro even at times when FV:C was within normal limits by heat inactivation of FV:C. Treatment with plasma and platelet transfusions as well as plasmapheresis induced definite but transient elevation of FV:C. Steroid therapy lowered the neutralizing antibody concentration and produced a rapid and persistent elevation of FV:C during two separate hospitalizations. This report describes a patient in whom levels of FV:Ag have been serially measured, and the presence of circulating immune complexes consisting of factor V and a neutralizing antibody have been directly demonstrated.     

Homozygous transcobalamin II deficiency maintained on oral hydroxocobalamin

A case of transcobalamin II (TCII) deficiency in which a total absence of TCII was demonstrated both functionally and immunologically is reported. Unlike previously described patients, this child has been maintained on oral hydroxocobalamin, 2 mg daily, without any parenteral supplementation for the last five years. At the age of six years her development is normal and her health is good. Plasma cobalamin levels are in the range of 3,000 ng/L and most of this appears to be bound to a molecule, which on gel filtration, elutes with albumin. In an extended family study, a clear separation of heterozygotes from both the propositus and from normal subjects suggests that the underlying defect in this condition is confined to a single gene.     

Carbon monoxide is a rapid modulator of recombinant and native P2X2 ligand-gated ion channels

Background and purpose:

Carbon monoxide (CO) is a potent modulator of a wide variety of physiological processes, including sensory signal transduction. Many afferent sensory pathways are dependent upon purinergic neurotransmission, but direct modulation of the P2X purinoceptors by this important, endogenously produced gas has never been investigated.

Experimental approach:

Whole-cell patch-clamp experiments were used to measure ATP-elicited currents in human embryonic kidney 293 cells heterologously expressing P2X₂, P2X₃, P2X_2/3 and P2X₄ receptors and in rat pheochromocytoma (PC12) cells known to express native P2X₂ receptors. Modulation was investigated using solutions containing CO gas and the CO donor molecule, tricarbonyldichlororuthenium (II) dimer (CORM-2).

Key results:

CO was a potent and selective modulator of native P2X₂ receptors, and these effects were mimicked by a CO donor (CORM-2). Neither pre-incubation with 8-bromoguanosine-3′,5′-cyclomonophosphate nor 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (a potent blocker of soluble guanylyl cyclase) affected the ability of the CO donor to enhance the ATP-evoked P2X₂ currents. The CO donor caused a small, but significant inhibition of currents evoked by P2X_2/3 and P2X₄ receptors, but was without effect on P2X₃ receptors.

Conclusions and implications:

These data provided an explanation for how CO might regulate sensory neuronal traffic in physiological reflexes such as systemic oxygen sensing but also showed that CO could be used as a selective pharmacological tool to assess the involvement of homomeric P2X₂ receptors in physiological systems.     

Budd‐Chiari syndrome in Sweden: epidemiology,clinical characteristics and survival – an 18‐year experience

Background: The exact incidence and prevalence of Budd‐Chiari syndrome (BCS) is unknown in the general population. Published reports differ in terms of the clinical characteristics, effects of therapy and survival. Aims: To investigate the epidemiology, clinical presentation and survival in patients with BCS. Methods: Retrospective multicentre study in Sweden reviewing the medical records of all patients with BCS 1986–2003, identified from the computerised diagnosis database of 11 hospitals, including all university hospitals and liver transplantation centres. Results: Forty‐three patients with BCS were identified, of whom nine (21%) had concomitant portal vein thrombosis. The mean age‐standardised incidence and prevalence rates in 1990–2001 were calculated to be 0.8 per million per year and 1.4 per million inhabitants respectively. Myeloproliferative disorders (38%), thrombophilic factors (31%) and oral contraceptives (30%) were common aetiological factors. Two or more risk factors were present in 44%. In 23%, no risk factor was evident. The median follow‐up time was 2.7 years. Seventy‐two percent were on anticoagulant therapy during follow‐up. Transjugular intrahepatic portosystemic shunting, surgical shunting procedures and liver transplantation were performed in 4, 6 and 18 patients respectively. Nineteen patients died. The overall transplantation‐free survival at 1, 5 and 10 years was 47, 28 and 17% respectively. Conclusions: Budd‐Chiari syndrome is a rare disorder; the mean age‐standardised incidence and prevalence rates in Sweden in 1990–2001 were calculated to be 0.8 per million per year and 1.4 per million inhabitants respectively. The presence of a myeloproliferative disorder was a common aetiological factor in our cohort and about half of the patients had a multifactorial aetiology. The transplantation‐free survival was poor.     

The role of corticosteroids in severe community-acquired pneumonia: a systematic review

Introduction  

The purpose of this review was to evaluate the impact of corticosteroids on the outcomes of patients with severe community-acquired pneumonia (CAP).     

Circulating inflammatory mediators and organ dysfunction after cardiovascular surgery with cardiopulmonary bypass: a prospective observational study

Introduction  

Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decades, but inflammatory activation in this setting is still unpredictable and is associated with several postoperative complications. Perioperative levels of macrophage migration inhibitory factor (MIF) and other inflammatory mediators could be implicated in adverse outcomes in cardiac surgery.     

Persistently normal alanine aminotransferase levels in HIV/HCV-coinfected patients: the role of steatosis

Objective

The frequency and significance of, and liver biopsy findings associated with, a persistently normal alanine aminotransferase (ALT) level in HIV/hepatitis C virus (HCV)‐coinfected patients are poorly characterized. We analysed factors associated with persistently normal ALT levels, defined as at least three consecutive normal ALT values over a 6‐month period, in a group of 381 HIV/HCV‐coinfected patients.

Methods

Patients were categorized into two groups according to ALT values: group 1, patients with persistently normal ALT levels; and group 2, patients with elevated ALT values. Possible interactions with host factors, HIV and HCV viral factors, antiretroviral treatment and histological features were examined.

Results

Thirty‐six patients (9.4%) had persistently normal ALT levels. None of the 36 patients had cirrhosis. Seven patients (19.4%) had a METAVIR fibrosis score of F3. In multivariate analysis, a lower mean METAVIR inflammation score [odds ratio (OR) 0.50, 95% confidence interval (CI) 0.28–0.89; P=0.017], the absence of steatosis (OR 0.43, 95% CI 0.20–0.90; P=0.026) and HCV genotype 4 infection (OR 2.81, 95% CI 1.15–6.68; P=0.023) were associated with persistently normal ALT levels.

Conclusion

The slower progression of chronic hepatitis in patients with persistently normal ALT levels could be related, in part, to a lower frequency of steatosis

     

Urethral injury associated with minimally invasive mid-urethral sling procedures for the treatment of stress urinary incontinence: a case series and systematic literature search

The introduction of the TVT™ has brought about dramatic changes in our practice as regards surgery for stress urinary incontinence, although the risk of bladder injury has caused concern. The subsequent development of tapes introduced through the obturator foramina may limit the rate of bladder injury, and some have suggested that cystoscopy is no longer required during stress incontinence surgery. Several cases of urethral injury referred to our unit have caused us concern about this approach. We present here brief details of these cases along with a systematic search of the literature on urethral injury following mid-urethral tape procedures.     

CONCURRENT MYELITIS AND GUILLAIN-BARRÉ SYNDROME AFTER VARICELLA INFECTION

Myelitis and Guillain-Barré syndrome occurring concurrently after varicella infection is very rare. A 34-year-old man presented with progressive flaccid tetraparesis, facial palsy, respiratory failure, sensory loss and urinary incontinence one week after varicella infection. Clinical, imaging and electrodiagnostic studies supported the diagnosis of myelitis and Guillain-Barré syndrome. He improved with intravenous acyclovir and gammaglobulin.