Differences between specificities of IgE and IgG4 antibodies: studies using recombinant chain 1 and chain 2 of the major cat allergen Felis domesticus (Fel d) I

IgE- and IgG4 antibodies were compared for reactivity with recombinant chain 1 and chain 2 of the cat allergen Felis domesticus (Fei d) I. Recombinanl chain 1 and chain 2 were coupled to sepharose and tested in IgE- and IgG4 radioallergosorbent test (RAST) experiments. Substantial IgE- and IgG4 binding was found. The fraction of Pel d I-specific antibody that bound to the recombinant chains was calculated. For chain 1, the mean value of this fraction was 0.30 for IgE and 0.23 for lgG4 (P= 0.05). For chain 2, the mean value of this fraction was 0.19 for IgE and 0.13 for IgG4 (P= 0.02). These results indicate that differences in fine specificity exist between IgE and IgG4 antibodies. Moreover, these findings support our results with chemically prepared peptides derived from these two chains and suggest that the B cells producing IgE antibodies are more likely to recognize a less ‘native’ form of Pel d I, compared with IgG4.     

Systematic review: prognostic tests of paracetamol‐induced acute liver failure

Aliment Pharmacol Ther 31 , 1064–1076

Summary

Background Paracetamol (acetaminophen) toxicity remains the leading cause of acute liver failure (ALF) in the developed world. In the UK, the recently modified King’s College Criteria are used to list patients for emergency liver transplantation, but these criteria have been criticized for their low sensitivity and for spectrum bias in their application. Aim To evaluate existing prognostic criteria critically for predicting death without transplantation in paracetamol‐induced ALF. Methods MEDLINE, EMBASE and CINAHL were searched to identify studies containing adult patients with paracetamol‐induced ALF. Selected studies were evaluated and data were pooled if appropriate, to calculate sensitivity, specificity and diagnostic odds ratios (DORs) of applied prognostic tests. Results Of 6507 studies identified, 14 were eligible for inclusion, evaluating 1960 patients. The original King’s College Criteria had a pooled sensitivity of 58.2% and specificity of 94.6%, with a DOR of 27.7. Addition of arterial lactate to the King’s College Criteria reduced the DOR to 26.1. Several other clinical and laboratory variables had higher DORs than the King’s College Criteria, but were only evaluated in single studies of limited quality. Conclusions The original King’s College Criteria remain well‐validated criteria with high prognostic accuracy. Other potential prognostic variables should be prospectively assessed in multicentre studies to refine the criteria further.     

Potentially Life-Threatening Cardiac Dysrhythmia in a Child with Selenium Deficiency and Phenylketonuria

ABSTRACT. Selenium deficiency is a frequent finding in children with phenylketonuria (PKU) receiving dietary treatment. We report the occurrence of episodic ventricular tachycardia in a 9-month-old infant with PKU. Serum selenium (Se), 0.13 μmol/1 (normal range 0.28–1.12 μmol/1, mean ± 2 SD), and whole blood glutathione peroxidase (GSHPX), 16 U/g Hb (normal range 19.5–34.3 U/g Hb, mean ± 2 SD), were low. Auscultation of cardiac rhythm is recommended during the routine follow-up of young children with PKU. Se deficiency should be considered in the aetiology of a dysrhythmia and corrected with Se supplementation.     

What nephrologists need to know about diagnostic test accuracy articles

Systematic reviews of randomized controlled trials are well‐recognized as the best evidence for an intervention and are also becoming more available for diagnostic test evaluation. In the absence of a well‐conducted and well‐reported systematic review clinicians must rely on primary studies to determine how best to interpret and understand diagnostic test information. Diagnostic test studies are abundant in the published literature; however, there are considerable limitations to the information provided in many of these papers and careful appraisal is required before the findings can be applied to individual patients. The current paper provides a framework for determining bias, clinical applicability and erroneous findings within a paper, allowing greater efficiency in selecting studies and deciding on the value of the information reported in them.     

Diagnostic accuracy of blood qualitative nucleic acid testing for polyomavirus-associated nephropathy in kidney recipients

Aim:   Polyomavirus-associated nephropathy (PVAN) is an important cause of graft loss following kidney transplantation and may only be diagnosed with kidney transplant biopsy. Early detection may improve outcomes by enabling early intervention. Serum polyomavirus polymerase chain reaction (PVPCR) has been used to identify patients at risk of PVAN, but prior studies have not assessed all patients with negative PVPCR with transplant biopsy, potentially overestimating test performance.
Methods:   We assessed the diagnostic accuracy of qualitative PVPCR for detection of PVAN in a population undergoing protocol biopsies. We included all patients receiving kidney or kidney-pancreas transplants and followed at Westmead Hospital, Sydney, Australia, between May 2002 and March 2007, excluding those with graft loss prior to 1 month post transplant or without PVPCR testing in the first 12 months. We compared PVPCR to contemporaneous transplant biopsies assessed with light microscopy and immunohistochemistry.
Results:   Of the 257 included patients, 246 (96%) underwent biopsy within 30 days of PVPCR. Eight of 36 patients with positive PVPCR had PVAN and one of 210 patients with negative PVPCR had PVAN. The point prevalence of PVAN was therefore 3.7%, with PVPCR sensitivity 89% (95% CI 57% to 99%) and specificity 88% (95% CI 83% to 92%). The negative predictive value is 99.5% (95% CI 97.3% to 100.0%).
Conclusion:   Qualitative PVPCR on serum is a reliable triage test for excluding the presence of PVAN. Screening for PVAN need not include biopsy in patients with negative PVPCR.     

Voluntary involvement in community health promotion: the Pawtucket Heart Health Program

The Pawtucket Heart Health Program employs a community activationapproach aimed at reducing cardiovascular morbidity and mortality.This approach is put into operation through the recruitmentof lay volunteers from the community to assist in planning,implementing, evaluating and managing various components ofthe Program. This unique approach of voluntary delivery of programmesis presented in this report. Strategies for the recruitment,interview and placement, training, maintenance and evaluationof volunteers are discussed. The characteristics of people whohave volunteered for specific administrative and service deliveryjobs with the Pawtucket Heart Health Program are also described.The volunteer delivery focus of the Program provides a modelfor adaptation by other public health projects.