Paul Glynne

Quinine-induced immune thrombocytopenic purpura followed by hemolytic uremic syndrome.

Immune thrombocytopenic purpura (ITP) mediated by quinine-dependent platelet reactive antibodies is well recognized. More recently there have been a number of reports of quinine-induced hemolytic-uremic syndrome (HUS). We describe a patient with quinine-induced immune thrombocytopenia who subsequently developed HUS after re-exposure to a single dose of this drug. To our knowledge, this is the first such case reported. Multiple quinine-dependent antibodies have been characterized in the patients serum. Initially, quinine-dependent antibodies were directed solely against the platelet glycoprotein complex GPIb/IX. After rechallenge with quinine, there was broadening of quinine-dependent antibody specificities, which were now also directed against the platelet glycoprotein complexes GPIb/IX and GPIIb/IIIa, endothelial cells, and leukocytes. We have shown quinine-dependent antibody-mediated endothelial cell activation, which supports an immunopathogenic role for quinine-dependent antibodies in the causation of this disease.

Epithelial inducible nitric-oxide synthase is an apical EBP50-binding protein that directs vectorial nitric oxide output.

Nitric oxide (NO), produced via inducible NO synthase (iNOS), can modulate polarized epithelial processes such as solute transport. Given the high reactivity of NO, we hypothesized that optimal NO regulation of polarized epithelial functions is achieved through compartmentalization of iNOS, allowing local NO delivery to its molecular targets. Here, we show that iNOS localizes to the apical domain of epithelial cells within a submembranous protein complex tightly bound to cortical actin. We further show that iNOS can bind to the apical PDZ protein, EBP50 (ezrin-radixin-moesin-binding phosphoprotein 50), an interaction that is dependent on the last three COOH-terminal amino acids of iNOS, SAL, but requires the presence of additional unknown cellular proteins. Mutation of these three COOH-terminal residues abolishes the iNOS-EBP50 interaction and disrupts the apical association of iNOS in transfected cells, showing that this COOH-terminal motif is essential for the correct localization of iNOS in epithelial cells. Apically localized iNOS directs vectorial NO production at the apical proximal tubule epithelial cell surface. These studies define human epithelial iNOS as an apical EBP50-binding protein and suggest that the physical association of iNOS with EBP50 might allow precise NO modulation of EBP50-associated protein functions.

Treating critical illness: the importance of first doing no harm.

Singer and Glynne present evidence to suggest that the short- term benefits of many interventions for treating critical illness may camouflage an underlying tendency to cause harm.

Bullous dermatoses in end-stage renal failure: Porphyria or pseudoporphyria?

Bullous dermatoses (BD) are well recognized in patients with end-stage renal disease (ESRD). It is important to distinguish pseudoporphyria (porphyrin accumulation due to decreased clearance) from true porphyrias, particularly those in which acute neurological attacks may occur. Investigation of the dialysis patient poses practical diagnostic difficulties because urinary porphyrin profiles are not available. We describe a patient on continuous ambulatory peritoneal dialysis (CAPD) with several recognized causative factors for porphyria cutanea tarda (PCT). The patient presented with a blistering photosensitive rash. We highlight the importance of investigating anuric patients with fractionation of both fecal and plasma porphyrins. Plasma porphyrins were grossly elevated (345 nmol/L; reference range, <13), whereas plasma porphyrins in a control group of CAPD patients without blistering rashes were only minimally elevated (mean, 23.9 nmol/L; SD, 11.0; n = 9). Fractionation of fecal porphyrins by high-performance liquid chromatography (HPLC) yielded a pattern typical of PCT. In addition to the contributory factors for PCT that were present, it is possible that porphyrin accumulation secondary to renal failure played a role in the expression of her disease. Patients with ESRD presenting with BD require careful evaluation, including fractionation of fecal porphyrins.

Role of the PDZ Scaffolding Protein in Tubule Cells in Maintenance of Polarised Function

Polarized tubule epithelial cell functions are dependent on correct delivery of effector proteins to the target apical or basolateral plasma membrane and associated cortical cytoskeleton. PDZ (Postsynaptic density protein 95/Drosophila Disks large/Zona occludens-1) domain-containing proteins have been identified as playing a critical role in membrane trafficking and sorting of ion transporters, receptors and other signalling proteins. These scaffolding proteins coordinate the assembly of functional plasma membrane multiprotein complexes, through PDZ domain binding to a consensus amino acid motif within the carboxyl-terminus of target proteins. The organization of these proteins into submembranous complexes may facilitate downstream signalling. Although several epithelial PDZ proteins that bind to a number of important mammalian proteins have been isolated, in many cases the significance of these interactions is unclear. However, the epithelial PDZ domain-containing Na+/H+ exchanger regulatory factor tethers the Na+/H+ exchanger and cystic fibrosis transmembrane regulator Cl– channel within an apical plasma membrane signalling complex, and has been shown to regulate the activity of these proteins. This article reviews the current evidence that supports a central role for the PDZ protein in the regulation of polarized tubule cell functions, such as vectorial solute transport.

Mass casualty incidents: are NHS staff prepared? An audit of one NHS foundation trust.

Background: Lack of knowledge of an NHS trust’s major incident policies by clinical staff may result in poorly coordinated responses during a mass casualty incident (MCI). Aim: To audit knowledge of the major incident policy by clinical staff working in a central London major acute NHS trust designated to receive casualties on a 24-h basis during a MCI. Methods: A 12-question proforma was distributed to 307 nursing and medical staff in the hospital, designed to assess their knowledge of the major incident policy. Completed proformas were collected over a 2-month period between December 2006 and February 2007. Results: A reply rate of 34% was obtained, with a reasonable representation from all disciplines ranging from nurses to consultants. Despite only 41% having read the policy in full, 70% knew the correct immediate action to take if informed of major incident activation. 76% knew the correct stand-down procedure. 56% knew the correct reporting point but less than 25% knew that an action card system was utilised. Nurses had significantly (p<0.01) more awareness of the policy than doctors. Conclusion: In view of the heightened terrorist threat in London, knowledge of major incident policy is essential. The high percentage of positive responses relating to immediate and stand-down actions reflects the rolling trust-wide MCI education programme and the organisational memory of the trust following several previous MCI in the capital. There is still scope for an improvement in awareness, however, particularly concerning knowledge of action cards, which are now displayed routinely throughout clinical areas and will be incorporated into induction packs.

Improvement in glycemic control and outcome corresponding to intensive insulin therapy protocol development.

Background: Intensive insulin therapy (IIT) has been shown to reduce mortality and morbidity in longer stay, critically ill patients. However, this has been demonstrated in a single site, whereas two multicentric studies have been terminated prematurely mainly due to hypoglycemia. Other difficulties with IIT include efficacy of glycemic control. This report describes how IIT can be improved by protocol simplification and removal of glucose supplementation. Methods: A clinical information system established at each bedspace guided staff through the IIT algorithms. Time spent within predefined glycemic ranges was calculated assuming a linear trend between successive measurements. Three groups were investigated retrospectively: IIT1 protocol,1 an updated IIT2 version, and intuitive nurse dosing of conventional insulin therapy (CIT). Results: Fifty consecutive, critically ill patients were included in each study group. Patient characteristics were similar in each group. The frequency of CIT and IIT2 blood glucose measurements were 11.6 and 11.5 measurements per day, respectively, while the IIT1 measurements were more frequent (14.5 measurements per day). The mean proportion of time spent in the target glycemic range (4.4–6.1 mmol/liter) was highest in the IIT2 group (34.9%), as compared to the IIT1 (22.9%) and CIT groups (20.3%) (p <.001). Survival at 28 days was 74.5% for IIT2 (highest), 68% for IIT1, and 48% for CIT (p = .02). There were a similar number of those experiencing a severe hypoglycemic event in each group. Conclusions: IIT protocol optimization was associated with increased glycemic control and improved 28–day survival. The better optimized IIT2 protocol provided tighter control than either the IIT1 or CIT protocol, without increased sampling or incidence of hypoglycemia. The clinical effectiveness of the IIT algorithm appeared to be improved by simplifying the protocol to meet the needs of the critical care unit.

Bilateral Adrenal Haemorrhage following Cystoprostatectomy: A Case Report

72-year-old gentleman underwent a cystoprostaectomy, formation of ileal conduit and extended elvic lymph node dissection for G3pT2 transiional cell carcinoma of the bladder. He initially rogressed well, but on the 10th postoperative ay developed nausea and vomiting, and rightided abdominal pain on a background of rising nflammatory markers. There was nothing untoard to find on examination but his mood was cutely depressed; the previous day he had been ooking forward to going home. A CT scan of the bdomen and pelvis revealed a high attenuation cm × 3.5 cm mass which could not be separated