Investigating Gene-Diet Interactions Impacting the Association Between Macronutrient Intake and Glycemic Traits

Few studies have demonstrated reproducible gene-diet interactions (GDIs) impacting metabolic disease risk factors, likely due in part to measurement error in dietary intake estimation and insufficient capture of rare genetic variation. We aimed to identify GDIs across the genetic frequency spectrum impacting the macronutrient-glycemia relationship in genetically and culturally diverse cohorts. We analyzed 33,187 participants free of diabetes from 10 National Heart, Lung, and Blood Institute Trans-Omics for Precision Medicine program cohorts with whole-genome sequencing, self-reported diet, and glycemic trait data. We fit cohort-specific, multivariable-adjusted linear mixed models for the effect of diet, modeled as an isocaloric substitution of carbohydrate for fat, and its interactions with common and rare variants genome-wide. In main effect meta-analyses, participants consuming more carbohydrate had modestly lower glycemic trait values (e.g., for glycated hemoglobin [HbA1c], -0.013% HbA1c/250 kcal substitution). In GDI meta-analyses, a common African ancestry-enriched variant (rs79762542) reached study-wide significance and replicated in the UK Biobank cohort, indicating a negative carbohydrate-HbA1c association among major allele homozygotes only. Simulations revealed that >150,000 samples may be necessary to identify similar macronutrient GDIs under realistic assumptions about effect size and measurement error. These results generate hypotheses for further exploration of modifiable metabolic disease risk in additional cohorts with African ancestry.

ARTICLE HIGHLIGHTS

We aimed to identify genetic modifiers of the dietary macronutrient-glycemia relationship using whole-genome sequence data from 10 Trans-Omics for Precision Medicine program cohorts. Substitution models indicated a modest reduction in glycemia associated with an increase in dietary carbohydrate at the expense of fat. Genome-wide interaction analysis identified one African ancestry-enriched variant near the FRAS1 gene that may interact with macronutrient intake to influence hemoglobin A1c. Simulation-based power calculations accounting for measurement error suggested that substantially larger sample sizes may be necessary to discover further gene-macronutrient interactions.

Mechanism of iodine release from iodoapatite in aqueous solution

Incongruent release of iodine from iodoapatite (Pb₅(VO₄)₃I) for immobilization of¹²⁹iodine, controlled by exchange of iodide and hydroxide in solution.

Alkaliphilic Bacillus species show potential application in concrete crack repair by virtue of rapid spore production and germination then extracellular calcite formation

AIMS

Characterization of alkaliphilic Bacillus species for spore production and germination and calcite formation as a prelude to investigate their potential in microcrack remediation in concrete.

METHODS AND RESULTS

Conditions, extent and timing of endospore production was determined by dark-field light microscopy; germination induction and kinetics were assessed by combining reduction in optical density with formation of refractile bodies by phase-contrast microscopy. Bacillus pseudofirmus was selected from several species as the most suitable isolate. Levels and timing of calcium carbonate precipitated in vitro by B. pseudofirmus were evaluated by atomic absorption spectroscopy and structural identity confirmed as calcite and aragonite by Raman spectroscopy and FTIR. The isolate produced copious spores that germinated rapidly in the presence of germinants l-alanine, inosine and NaCl. Bacterial cells produced CaCO₃ crystals in microcracks and the resulting occlusion markedly restricted water ingress.

CONCLUSIONS

By virtue of rapid spore production and germination, calcium carbonate formation in vitro and in situ, leading to sealing of microcracks, B. pseudofirmus shows clear potential for remediation of concrete on a commercial scale.

SIGNIFICANCE AND IMPACT OF THE STUDY

Microbial sealing of microcracks should become a practicable and sustainable means of increasing concrete durability.

Randomised clinical trial: vercirnon, an oral CCR9 antagonist, vs. placebo as induction therapy in active Crohn's disease

BACKGROUND

Many patients with active Crohn's disease do not adequately respond to therapies, highlighting the need for new treatments.

AIMS

To conduct a randomised, double-blind, placebo-controlled phase 3 study to assess the efficacy and safety of vercirnon, an oral inhibitor of CC chemokine receptor-9, for the treatment of patients with moderately-to-severely active Crohn's disease.

METHODS

Patients with a Crohn's Disease Activity Index (CDAI) of 220-450, plus evidence of active disease (endoscopically confirmed or elevation of both C-reactive protein and faecal calprotectin), who had failed corticosteroid or immunosuppressant therapy were enrolled. Patients were equally randomised to receive placebo, vercirnon 500 mg once daily or vercirnon 500 mg twice daily. The primary endpoint was clinical response, defined as a 100-point decrease in CDAI from baseline to week 12.

RESULTS

Six hundred and eight patients were randomised. Patient characteristics and baseline demographics were similar among the groups. The proportions of patients achieving a clinical response were 25.1%, 27.6% and 27.2% for placebo, once daily and twice daily respectively; treatment differences were not significant (2.5%; 95% confidence interval, CI -6.1% to 11.0%, P = 0.546 for once daily vs. placebo, and 2.1%; 95% CI -6.5% to 10.7%, P = 0.648 for twice daily vs. placebo). Adverse events were reported in 69.8%, 73.3% and 78.1% with serious adverse events in 8.9%, 5.9%, and 6.0% of patients in the placebo, once-daily and twice-daily groups, respectively.

CONCLUSIONS

We did not demonstrate efficacy of vercirnon as an induction therapy in patients with moderately-to-severely active Crohn's disease; its effect in maintenance therapy was not addressed.

Collaborative study for the establishment of the WHO 3(rd) International Standard for Endotoxin, the Ph. Eur. endotoxin biological reference preparation batch 5 and the USP Reference Standard for Endotoxin Lot H0K354

An international collaborative study was organised jointly by the World Health Organization (WHO)/National Institute for Biological Standards and Control (NIBSC), the United States Pharmacopeia (USP) and the European Directorate for the Quality of Medicines & HealthCare (EDQM/Council of Europe) for the establishment of harmonised replacement endotoxin standards for these 3 organisations. Thirty-five laboratories worldwide, including Official Medicines Control Laboratories (OMCLs) and manufacturers enrolled in the study. Three candidate preparations (10/178, 10/190 and 10/196) were produced with the same material and same formulation as the current reference standards with the objective of generating a new (3(rd)) International Standard (IS) with the same potency (10 000 IU/vial) as the current (2(nd)) IS, as well as new European Pharmacopoeia (Ph. Eur.). and USP standards. The suitability of the candidate preparations to act as the reference standard in assays for endotoxin performed according to compendial methods was evaluated. Their potency was calibrated against the WHO 2(nd) IS for Endotoxin (94/580). Gelation and photometric methods produced similar results for each of the candidate preparations. The overall potency estimates for the 3 batches were comparable. Given the intrinsic assay precision, the observed differences between the batches may be considered unimportant for the intended use of these materials. Overall, these results were in line with those generated for the establishment of the current preparations of reference standards. Accelerated degradation testing of vials stored at elevated temperatures supported the long-term stability of the 3 candidate preparations. It was agreed between the 3 organisations that batch 10/178 be shared between WHO and EDQM and that batches 10/190 and 10/196 be allocated to USP, with a common assigned value of 10 000 IU/vial. This value maintains the continuity of the global harmonisation of reference materials and unitage for the testing of endotoxins in parenteral pharmaceutical products. Based on the results of the collaborative study, batch 10/178 was established by the European Pharmacopoeia Commission as the Ph. Eur. Endotoxin Biological Reference Preparation (BRP) batch 5. The same batch was also established by the Expert Committee on Biological Standardisation (ECBS) of WHO as the WHO 3(rd) IS for Endotoxin. Batch 10/190 was adopted as the USP Endotoxin Reference Standard, lot H0K354 and vials from this same batch (10/190) will serve as the United States Food and Drug Administration (USFDA) Endotoxin Standard, EC-7.

Factor VIII Bypassing Activity (FEIBA) assays: standardization and development of the 1st NIBSC Working Standard for FEIBA--results from a collaborative study

Factor-Eight-Inhibitor-Bypassing-Activity (FEIBA) is a bypassing-agent used to control spontaneous bleeding or cover surgical interventions in Haemophiliacs who develop neutralizing antibodies against FVIII/FIX. The market lot-release of FEIBA is dependent on specific clot-based assays, carried out by both the manufacturer and regulatory authorities, relative to manufacturer's in-house standards, which are produced on a small-scale and are replaced frequently. We sought to standardize the FEIBA assay by developing a FEIBA primary standard which would be internationally available in sufficiently large quantities, with a predicted lifetime of many years. A collaborative study involving the manufacturer and three regulatory authorities, was carried out in which a candidate material, sample B (06/172), was calibrated by assays relative to the manufacturer's in-house FEIBA standards (C and D). All laboratories used their routine validated methods (16 APTT-assays, 8 ACTIN-FS-assays and 27 DAPTTIN-assays). Intra-laboratory geometric coefficients of variation (GCVs) for candidate B ranged from 3% to 29% (GCVs <9% from majority of labs). Assessment of inter-laboratory variability gave overall GCV values of 6.9% and 4.4% relative to standards C and D, respectively, for all methods. There was good agreement in potency estimation between laboratories using each of the three methods, with the overall potencies by the three methods differing by less than 10% of the overall mean, giving an overall combined potency of 28.0 units per ampoule. All participants agreed that candidate B (06/172) be established as the 1st NIBSC Working Standard for FEIBA with an assigned potency of 28.0 units per ampoule, based on combined results for both methods, relative to either standard C or D.

Diabetes is associated with impairment of uterine contractility and high Caesarean section rate

AIMS/HYPOTHESIS

The prevalence of births worldwide complicated by diabetes mellitus is increasing. In the UK, for example, <25% of diabetic women have a non-instrumental vaginal delivery. Strikingly, more than half the Caesarean sections (CS) in these patients are non-elective, but the reasons for this are not understood. We have tested the hypothesis that poor myometrial contractility as a consequence of the disease contributes to this high CS rate.

METHODS

We compared spontaneous, high K depolarisation and oxytocin-induced contractions from diabetic and matched control patients having an elective CS. To investigate the mechanism of any differences we measured intracellular Ca, and performed western blotting and compared the tissues histologically.

RESULTS

There was significantly decreased contraction amplitude and duration in uteri from diabetic compared with control patients, even when possible confounders such as BMI were analysed. Reduced intracellular calcium signals and expression of calcium entry channels were found in uteruses from diabetic patients, which, along with a reduction in muscle content found on histological examination, could explain the reduced force. Myometrium from diabetic patients was responsive to oxytocin, but still did not reach the levels found in non-diabetic patients.

CONCLUSIONS/INTERPRETATIONS

These are the first data investigating myometrium in diabetic patients and they support the hypothesis that there is poorer contractility even in the presence of oxytocin. The underlying mechanism is related to reduced Ca channel expression and intracellular calcium signals and a decrease in muscle mass. We conclude that these factors significantly contribute to the increased emergency CS rate in diabetic patients.

An international collaborative study to establish a replacement World Health Organization International Standard for human immunodeficiency virus 1 RNA nucleic acid assays

BACKGROUND AND OBJECTIVES

An international collaborative study was undertaken to identify a replacement for the World Health Organization (WHO) 1st International Standard for human immunodeficiency virus 1 (HIV-1) RNA for use in nucleic acid-based techniques (NAT) (code 97/656). In the original study to establish the 1st International Standard, a second candidate material (code 97/650) had been shown to perform well and this was re-evaluated to establish whether it would be a suitable replacement.

MATERIALS AND METHODS

Eight laboratories from six different countries participated in the collaborative study to evaluate the candidate replacement standard. A total of eight different NATs were used, five in a quantitative format and three qualitative, of which five were commercially available.

RESULTS

The results showed that the estimates of RNA copies in the current study were generally in line with those of the original study and there was no evidence of any drift in overall levels expressed in International Units (IU) for the candidate standard between the two studies. Furthermore, it was shown to be stable over long-term storage at -20 degrees C.

CONCLUSIONS

The candidate material code 97/650 was established by the WHO as the 2nd International Standard for HIV-1 RNA for use in NAT and assigned a unitage of 5.56 log(10) (363 078) IU/vial.

Calibration of human coagulation factor VIII concentrate Ph. Eur. BRP Batch 4 for use in potency assays

The European Pharmacopoeia Biological Reference Preparation (Ph. Eur. BRP) Batch 4 was established as an international common working standard for potency determination of human coagulation factor VIII (FVIII) preparations to replace the dwindling stocks of the BRP Batch 3, the current European standard. Similarly, stocks of the current World Health Organisation 7th International Standard (WHO 7th IS) were also running low. Therefore a project was jointly organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM, Council of Europe) and the National Institute for Biological Standards and Control (NIBSC, UK) in order to replace both standards concomitantly. The potency of the BRP Batch 4 was assigned during an international collaborative study involving 38 laboratories with reference to the WHO 7th IS and the BRP Batch 3. Four candidate materials, 2 plasma-derived (samples A and C) and 2 recombinant (samples B and D) have been evaluated, sample C being the specific candidate for the replacement of the BRP Batch 3. Participants were instructed to perform 8 independent assays following their own routine validated methods, by either the one-stage clotting assay or the chromogenic assay, or both. Laboratories returned 22 data sets for the clotting assay and 30 data sets for the chromogenic assay. This publication reports the results obtained with both assays but only the results of the chromogenic assay are highlighted in the conclusions, as it is the assay prescribed by the European Pharmacopoeia. Data were analysed separately for both assays. The consensus potency value was calculated as the unweighted geometric mean of the unweighted geometric means of each individual laboratory. For sample C, there was a significant difference in potency estimate between the chromogenic and the clotting assay. It was therefore not possible to reconcile both results. The chromogenic potencies however were in very good agreement being 10.4 IU/ampoule (n = 30), when assessed against both standards. The inter-laboratory geometric coefficient of variation (GCV) was 4.8 % and 7.1 % against the WHO 7th IS and the BRP Batch 3 respectively. The Ph. Eur. BRP Batch 4 is a freeze-dried, plasma-derived concentrate. The material was filled in approximately 20,000 ampoules and lyophilised. The final residual water content is 0.33 %. Based on accelerated degradation studies, the stability of the material is suitable for a reference preparation. The candidate Ph. Eur. BRP Batch 4 was adopted at the 136th session of the European Pharmacopoeia Commission in March 2010. The standard will be available from the EDQM with the catalogue number H0920000 upon exhaustion of the current batch.

Hemoperfusion with Amberlite resin in the treatment of self-poisoning

Ten patients with various intoxications were treated with resin hemoperfusion. Three of four patients with grade IV coma due to tricyclic antidepressant (TCA) poisoning could be extubated during or on termination of hemoperfusion. Clearance values of 135--185 and 190--200 ml/min were obtained for amitriptyline and nortriptyline, respectively. One patient with severe chloral hydrate poisoning could be extubated after less than one hour's hemoperfusion. A clearance of 140 ml/min was obtained in a uremic patient with AV block II due to digitoxin intoxication. Four patients with mushroom poisoning were treated with combined hemoperfusion-hemodialysis. A transient fall in platelet count was seen in all patients. Resin hemoperfusion is of definite value in selected, severe cases of self-poisoning with psychotropic drugs such as TCA and possibly in cases of mushroom poisoning where the prognosis with hemodialysis and supportive therapy is doubtful.

Self-poisoning treated in the ICU

This retrospective study compares number and type of self-poisonings admitted to the intensive care units (ICU) at Sahlgren's Hospital, Gothenburg, during 1972 and 1976. The total number of patients requiring intensive care was unchanged, but a change in the pattern of self-poisoning was seen. In 1976 the number of patients requiring intensive care following acute alcohol intoxication had increased, whereas the number of barbiturate and methaqualone poisonings decreased. Tricyclic antidepressants formed the largest group in both years. Fewer patients needed endotracheal intubation and IPPV in 1976 than in 1972. Also, fewer complications were seen, and the death rate among ICU-treated patients decreased. In the Gothenburg area barbiturates accounted for one half of all deaths due to self-poisoning and tricyclic antidepressants for one fifth. Any expected decrease in intensive care as a result of fewer barbiturate and methaqualone poisonings was obscured by an increase in severe alcohol intoxication.

Clinical aspects of tricyclic antidepressant poisoning

Self-poisoning with antidepressant drugs was studied retrospectively in 225 patients admitted to an intensive care unit. Amitriptyline accounted for the overwhelming majority of cases (70%); 106 patients (47%) had taken two or more drugs, in 81 patients (36%) ethanol was found in the blood. Four patients (2%) died. On admission, 111 patients (49%) were unconscious (grade III). A further 30 patients (13%) were in grade IV coma, and of these 27 had taken amitriptyline. Twenty-four hours after admission, 22 patients (10%) remained in coma. Thirty-six patients (16%) required assisted ventilation. Nineteen patients (8%) had convulsions and 6 (3%) aspired stomach contents. Sixty-one patients (27%) had a widened QRS interval exceeding 100 msec, 18 (30%) of them required assisted ventilation, 21 (34%) were in stage IV coma and 15 (25%) had convulsions. This relationship between a widened QRS interval and the severity of intoxication should be considered in the initial assessment of patients with tricyclic antidepressant poisoning.

Stable lyophilized reagents for the serum ferritin assay

Two monoclonal antibodies to human ferritin, including one that was coupled to horseradish peroxidase, were lyophilized. These reagents show little loss of activity on reconstitution and demonstrate acceptable stability in the accelerated degradation test. When applied in a simple ELISA for the assay of serum ferritin along with the WHO standard for serum ferritin (80/602) they provide a robust assay with standardized reagents which is potentially suitable for use as a reference assay.

Establishment of replacement batches for heparin low-molecular-mass for calibration CRS, and the International Standard Low Molecular Weight Heparin for Calibration

An international collaborative study involving fourteen laboratories has taken place, organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) with National Institute for Biological Standards & Control (NIBSC) (in its capacity as a World Health Organisation (WHO) Laboratory for Biological Standardisation) to provide supporting data for the establishment of replacement batches of Heparin Low-Molecular-Mass (LMM) for Calibration Chemical Reference Substance (CRS), and of the International Reference Reagent (IRR) Low Molecular Weight Heparin for Molecular Weight Calibration. A batch of low-molecular-mass heparin was donated to the organisers and candidate preparations of freeze-dried heparin were produced at NIBSC and EDQM. The establishment study was organised in two phases: a prequalification (phase 1, performed in 3 laboratories in 2005) followed by an international collaborative study (phase 2). In phase 2, started in March 2006, molecular mass parameters were determined for seven different LMM heparin samples using the current CRS batch and two batches of candidate replacement material with a defined number average relative molecular mass (Mn) of 3,700, determined in phase 1. The values calculated using the candidates as standard were systematically different from values calculated using the current batch with its assigned number-average molecular mass (Mna) of 3,700. Using raw data supplied by participants, molecular mass parameters were recalculated using the candidates as standard with values for Mna of 3,800 and 3,900. Values for these parameters agreed more closely with those calculated using the current batch supporting the fact that the candidates, though similar to batch 1 in view of the production processes used, differ slightly in terms of molecular mass distribution. Therefore establishment of the candidates was recommended with an assigned Mna value of 3,800 that is both consistent with phase 1 results and guarantees continuity with the current CRS batch. In phase 2, participants also determined molecular weight parameters for the seven different LMM heparin samples using both the 1st IRR (90/686) and its Broad Standard Table and the candidate World Health Organization (WHO) 2nd International Standard (05/112) (2nd IS) using a Broad Standard Table established in phase 1. Mean molecular weights calculated using 2nd IS were slightly higher than with 1st IRR, and participants in the study indicated that this systematic difference precluded establishment of 2nd IS with the table supplied. A replacement Broad Standard Table has been devised on the basis of the central recalculations of raw data supplied by participants; this table gives improved agreement between values derived using the 1st IRR and the candidate 2nd IS. On the basis of this study a recommendation was made for the establishment of 2nd IS and its proposed Broad Standard Table as a replacement for the 1st International Reference Reagent Low Molecular Weight Heparin for Molecular Weight Calibration. Unlike the 1st IRR however, the candidate material 2nd IS is not suitable for use with the method of Nielsen. The candidate materials were established as heparin low-molecular-mass for calibration batches 2 and 3 by the Ph. Eur. Commission in March 2007 and as 2nd IS low-molecular-weight heparin for molecular weight calibration (05/112) by the Expert Committee on Biological Standardization in November 2007.

International collaborative study to establish immunoglobulin (anti-D test) BRP batch 1

An international collaborative study was organised to establish a European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) and United States (US) Food and Drug Administration (FDA) reference preparation for the test for anti-D (anti-Rho) antibodies in human normal immunoglobulin for intravenous administration (IGIV). A candidate positive control (IGIV+anti-D) and negative control IGIV were compared to corresponding World Health Organization (WHO) International Reference Reagents using a direct haemagglutination reference method. Sixteen (16) laboratories participated in the collaborative study. Further to completion of the study, the materials assayed in the study were granted the status of Ph. Eur. and US FDA reference preparations for controlling the levels of anti-D in IGIV.

A World Health Organization International Standard for hepatitis A virus RNA nucleic acid amplification technology assays

BACKGROUND AND OBJECTIVES

Sixteen laboratories from 10 different countries participated in an international collaborative study to evaluate candidate materials as the first World Health Organization (WHO) International Standard for hepatitis A virus (HAV) RNA nucleic acid amplification technology (NAT) assays.

MATERIALS AND METHODS

Five candidate materials were analysed in this study: materials AA and BB were lyophilized, while materials CC, DD and EE were liquid preparations. Samples were diluted in pooled plasma or in pooled cryo-poor plasma (sample EE). Serial dilutions of the candidate materials were tested by each laboratory in four independent assays and the results were analysed statistically.

RESULTS

The mean log(10)'equivalents' per ml were 5.29 for sample AA, 5.07 for sample BB, 4.99 for sample CC, 5.40 for sample DD and 4.08 for sample EE.

CONCLUSIONS

Based on the results of this study, sample AA was established as the first International Standard for HAV RNA NAT assays at the WHO Expert Committee on Biological Standardizaton (ECBS) meeting held in February 2003. The code number of this preparation is 00/560 and the potency, based on the study, is 100 000 International Units (IU)/ml.

World Health Organization collaborative study to establish a replacement WHO international standard for hepatitis C virus RNA nucleic acid amplification technology assays

BACKGROUND AND OBJECTIVES

A collaborative study was undertaken to establish a replacement for the current (1st) World Health Organization (WHO) hepatitis C virus (HCV) International Standard, 96/790.

MATERIALS AND METHODS

Both the 1(st) International Standard and the replacement standard were prepared from the same starting material by diluting a high titre genotype 1a HCV isolate in pooled, human plasma. The only difference was that each standard was lyophilized in two, separate lyophilisation runs but under the same conditions.

RESULTS

In the study to establish the 1st International Standard, no significant difference in potency was found between the material eventually designated as the 1st International Standard and that now selected as the 2nd International Standard. The present study also showed no significant differences between the materials stored at -20 degrees C and no evidence of degradation over 5 years.

CONCLUSIONS

Material 96/798 was established as the 2nd HCV International Standard and assigned the same unitage as the 1st International Standard, i.e. 10(5) IU/ml (50,000 IU/vial).

International collaborative study to evaluate a candidate reference preparation to define an appropriate specified limit of anti-D in intravenous immunoglobulin products

BACKGROUND AND OBJECTIVES

The aim of the study was to evaluate a lyophilized intravenous immunoglobulin (IVIG) preparation containing anti-D (02/228; nominal reciprocal titre of 8) for its suitability to define the maximum limit of anti-D in IVIG products when used in a proposed reference method of direct haemagglutination of papain-treated erythrocytes, in an international collaborative study.

MATERIALS AND METHODS

Twenty laboratories tested 02/228 along with a negative control IVIG preparation and four IVIG samples containing different levels of anti-D. Nineteen laboratories performed direct haemagglutination methodology using papain-treated erythrocytes; five of these laboratories and one additional laboratory performed their in-house haemagglutination methodology (all indirect antiglobulin tests).

RESULTS

The mode titre of 02/228, obtained by using the proposed reference method, was 8 (62.5% of tests). However, there was wide variation in haemagglutination titres between laboratories for three of the four samples. Correcting the titres of the samples relative to those of the proposed reference preparation reduced the interlaboratory variability and increased the frequency of the mode titres in three out of four samples. The indirect antiglobulin tests also showed wide interlaboratory variability and were less sensitive than the direct method in four laboratories. Eleven of the 14 laboratories that expressed an opinion considered that the level of anti-D in 02/228 was appropriate to define a specified limit.

CONCLUSIONS

Our results demonstrate the necessity of using a reference preparation to define the maximum level of anti-D in IVIG products and ensure sufficient sensitivity in haemagglutination testing methodology. On the basis of these results, members of the European Pharmacopoeia Expert Group 6B recommended revision of the appropriate monograph to include this new specification and test. The Food and Drug Administration in the USA intends to adopt the same maximal specification defined by the reference preparation and to recommend the same test for the safety of IVIG products. Preparations 02/228 and 02/226 were also established by the World Health Organization as International Reference Reagents to standardize haemagglutination testing for anti-D in normal IVIG products.

Collaborative study to calibrate hepatitis C virus genotypes 2-6 against the HCV International Standard, 96/790 (genotype 1)

BACKGROUND AND OBJECTIVES

A major requirement of a hepatitis C virus (HCV) RNA nucleic acid amplification technology (NAT) assay validation is the ability of the assay to detect the six major genotypes of HCV with equivalent sensitivities. The aim of this study was to characterize and calibrate an HCV genotype panel for use in such studies.

MATERIALS AND METHODS

Panels consisting of the first International Standard (IS) for HCV RNA NAT assays (96/790; HCV genotype 1a) and isolates of genotypes 2-6 were sent to 17 laboratories worldwide which use a variety of NAT tests, both qualitative and quantitative. The HCV RNA content of each panel member was determined and the mean titre calculated in International Units/ml (IU/ml).

RESULTS

The calculated mean titres (calibrated against the HCV International Standard), in log10 IU/ml, of the genotype 2-6 samples were 3.99, 3.81, 4.14, 4.18 and 4.61, respectively.

CONCLUSIONS

An HCV genotype panel, calibrated in IU/ml, has been established and should be valuable for assay validation. All the genotypes were detected by all the assays used, but it was not possible to demonstrate that the genotypes were detected with equal efficiencies.

Clonal analysis of a human antimouse antibody (HAMA) response

Circulating human antimouse antibodies (HAMAs) directed to mouse immunoglobulin G (IgG) are clinically significant, compromising mouse antibody therapy and imaging, and interfering in immunological assays. To investigate the HAMA response, 20 stable cell lines secreting human monoclonal antibodies reactive with mouse IgG were established from a donor with a history of exposure to mice. Their subclass and domain specificities were established by solid-phase binding, indirect haemagglutination assays and immunoblotting, using Igs of known subclass and Ig fragments. The heavy-chain variable region gene usage was determined for 12 HAMAs. Eight HAMAs were IgM, 11 HAMAs were IgG4 and one HAMA was IgG1, indicating an IgG4-dominated response. All of the IgG HAMAs reacted with epitopes present on the Fc portion; one was subclass-specific, nine were subclass-restricted and two were pan-IgG-reactive. Measurement of their affinities gave dissociation constants typically in the nanomolar range. Seven and five HAMAs were derived from variable heavy-chain 3 (VH3) and VH1 gene segments, respectively. The IgG HAMAs used different VH segments to the IgM HAMAs. JH regions were coded by JH4 in eight HAMAs. DH segment usage appeared to be restricted in the IgM HAMAs. Two IgG HAMAs were clonally related. These monoclonal HAMAs are potentially useful as reagents for detecting mouse IgG and as reference reagents for the investigation of the HAMA response in patients undergoing mouse monoclonal antibody therapy and for the investigation of the influence of HAMAs on immunodiagnostic tests.

Establishment of the first World Health Organization International Standard for human parvovirus B19 DNA nucleic acid amplification techniques

BACKGROUND AND OBJECTIVES

A collaborative study, involving 26 laboratories from 14 countries, was carried out in order to establish a World Health Organization (WHO) International Standard for human parvovirus B19 (B19) DNA nucleic acid amplification techniques (NAT).

MATERIALS AND METHODS

Four samples: AA, BB (which were lyophilized), CC and DD (which were liquid preparations) were analysed using several different NAT assays. The mean B19 DNA content of each sample was determined for each laboratory using an end-point dilution method.

RESULTS

There was good agreement between the overall mean 'equivalents'/ml obtained by the different assays. The mean log(10) 'equivalents'/ml were 5.76 for sample AA, 5.73 for sample BB, 5.82 for sample CC and 7.70 for sample DD. The differences in titre among samples AA, BB and CC were not statistically significant, but the titre of DD was significantly higher.

CONCLUSIONS

Despite the range of NAT assays used in the study, it was possible to calculate the mean B19 DNA concentrations in the four preparations. Lyophilized preparation AA was established as the first International Standard for B19 DNA NAT assays and was assigned a concentration of 10(6) international units (IU)/ml.

Familiality and heritability of subtypes of attention deficit hyperactivity disorder in a population sample of adolescent female twins

OBJECTIVE

Attention deficit hyperactivity disorder (ADHD) is a highly heritable but clinically heterogeneous syndrome. The study examined the familiality and heritability of ADHD subtypes as defined by DSM-IV and by latent-class analysis in a population sample of adolescent female twins.

METHOD

To determine which elements of ADHD cluster together, latent-class analysis was applied to data obtained from parents on the 18 DSM-IV ADHD symptoms in 4,036 female twins age 13-23 years in a population sample identified from the registry of all births in Missouri for the years 1968-1996. Relative risk and odds ratios were used to assess within-subtype and between-subtype familiality and heritability of both DSM-IV and latent-class ADHD subtypes.

RESULTS

Latent-class analysis was most compatible with the existence of three mild and three severe classes of ADHD symptoms in the general population. The three severe classes showed moderate overlap with DSM-IV ADHD subtypes. The primarily inattentive and combined subtypes of DSM-IV ADHD co-clustered within families. The primarily hyperactive/impulsive DSM-IV subtype and the individual latent-class analysis subtypes did not co-cluster. Subtypes defined by both approaches were highly heritable.

CONCLUSIONS

Unlike DSM-IV subtypes of ADHD, latent-class ADHD subtypes appear to be independently transmitted in families. These classes may be more appropriate targets for molecular genetic studies of ADHD.

Latent class analysis of ADHD and comorbid symptoms in a population sample of adolescent female twins

Attention-deficit/hyperactivity disorder (ADHD) is a phenotypically heterogeneous and highly heritable syndrome. which commonly co-occurs with other psychiatry disorders. To assess the role of genetic influences in ADHD, we used latent class analysis (LCA) to identify subtypes of ADHD taking into account its comorbidity with separation anxiety, oppositional defiant disorder (ODD), and three major depression symptoms. A structured interview was used to collect diagnostic data from a population sample of 2,904 adolescent female twins and their parents. LCA was applied to ADHD. separation anxiety. ODD symptom profiles obtained from the twins' parents, and major depression symptom profiles obtained from the twins' self-report. Odds ratios were used to test for familiality of class membership by examining the effect of zygosity on twin concordance within and between latent classes. Structural equation modeling was used to compute heritabilities for latent class membership. LCA revealed three ADHD categories of clinical interest: an inattentive subtype without comorbidity, a second inattentive subtype with increased number of ODD symptoms. and a combined inattentive/hyperactive-impulsive type with elevated levels of ODD, separation anxiety, and depressive symptoms. LCA also distinguished an ODD class and a separation anxiety class, each without increased levels of other comorbid symptoms; a second ODD class co-occurring with increased separation anxiety and depression symptoms; and a pure depression class. Odds ratios for MZ contrasted with DZ twin concordance for individual latent class membership ranged from 2.5 to 19.4. Overall, 66% of MZ pairs, but only 36% of DZ pairs, were assigned to the same latent class, consistent with a genetic hypothesis for latent class membership. Individual class membership was shown to have high heritability ranging from .34-.85. The pattern of latent classes suggested that in the general female adolescent population, there are three highly heritable ADHD subtypes, two of which are comorbid with other disorders. These classes were consistent with a genetic hypothesis for ADHD, with each class potentially reflecting a unique genetic subtype.

Variation in melanin content and composition in type V and VI photoexposed and photoprotected human skin: the dominant role of DHI

A combination of techniques, including high-performance liquid chromatography (HPLC), spectrophotometric measurements, and a novel method for quantifying melanosome morphology, were applied to the analysis of melanin content and composition in highly pigmented (Fitzpatrick type V and VI) human skin. We found that total epidermal melanin content is significantly elevated in photoexposed type V and VI skin (approximately 1.6 x), while analysis of individual melanin components suggests that pheomelanin content increases only slightly, whereas 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-eumelanin and to a greater extent 5,6-dihydroxyindole (DHI)-eumelanin content are both markedly elevated. Analysis of the relative composition of epidermal melanin in these subjects revealed that DHI-eumelanin is the largest single component (approximately 60-70%), followed by DHICA-eumelanin (25-35%), with pheomelanin being a relatively minor component (2-8%). Moreover, there was a comparative enrichment of DHI-eumelanin at photoexposed sites, with a corresponding decline in the relative contributions from DHICA-eumelanin and pheomelanin. There was also a good correlation and close agreement between the concentration of spheroidal melanosomes determined by morphological image analysis and the concentration of pheomelanin determined by a combination of HPLC and spectrophotometric analysis (r = 0.89, P < 0.02). This study demonstrates the usefulness of melanosome morphology analysis as a sensitive new method for the quantification of melanin composition in human skin. The data also suggest that DHI-eumelanin formation is the dominant pathway for melanin synthesis in heavily pigmented (Fitzpatrick V and VI) skin types in vivo, and is the favoured pathway when melanin production is increased in chronically photoexposed skin.

An exploration of the value of the personal doctor-patient relationship in general practice

BACKGROUND

Within the context of general practice, continuity of care creates an opportunity for a personal doctor-patient relationship to develop which has been associated with significant benefits for patients and general practitioners (GPs). Continuity of care is, however, threatened by trends in the organisational development of primary health care in the United Kingdom and its intrinsic role within general practice is currently the subject of debate.

AIMS

To determine how many patients report having a personal doctor and when this is most valued, to compare the value of a personal doctor-patient relationship with that of convenience, and to relate these findings to a range of patient, GP, and practice variables.

DESIGN OF STUDY

Cross sectional postal questionnaire study.

SETTING

Nine hundred and ninety-six randomly selected adult patients from a stratified random sample of 18 practices and 284 GP principals in Oxfordshire.

METHOD

Qualitative interviews with patients and GPs were conducted and used to derive a parallel patient and GP questionnaire. Each patient (100 from each practice) was invited to complete a questionnaire to evaluate their experience and views concerning personal care. All GP principals currently practising in Oxfordshire were sent a similar questionnaire, which also included demographic variables.

RESULTS

Overall, 75% of patients reported having at least one personal GP. The number of patients reporting a personal GP in each practice varied from 53% to 92%. Having a personal doctor-patient relationship was highly valued by patients and GPs, in particular for more serious, psychological and family issues when 77-88% of patients and 80-98% of GPs valued a personal relationship more than a convenient appointment. For minor illness it had much less value.

CONCLUSIONS

Patients and GPs particularly value a personal doctor-patient relationship for more serious or for psychological problems. Whether a patient has a personal GP is associated with their perception of its importance and with factors which create an opportunity for a relationship to evolve.

Identification of a major, CsrRS-regulated secreted protein of Group A streptococcus

CsrR/CsrS (CovR/CovS) is a two-component regulator of extracellular virulence factors in Group A streptococcus, but the full range of regulated exoproteins is unknown. Since CsrR represses expression of regulated factors, culture supernates of wild-type and CsrR(-)mutant strains were compared by two-dimensional gel electrophoresis (2DGE) to identify regulated exoproteins. Supernates of DeltacsrRS(-)mutant, but not wild-type, bacteria contained an abundant 23 kDa protein. The N-terminal sequence of this spot corresponded to a putative open reading frame (ORF) in the streptococcal genome. In a mobility shift assay, phosphorylated CsrR bound to a PCR amplicon that included sequences upstream of this ORF. By primer extension analysis, the ORF (designated mspA, for Mucoidy-associated Secreted Protein) was expressed in mid- and late-exponential phase in a DeltacsrRS(-)mutant. The presence of an in-frame deletion in mspA did not affect colony appearance, mucoidy or in vitro growth, and there was no difference between DeltamspA and wild-type strains in a mouse model of skin infection. MspA is co-regulated with other factors required for dermonecrosis (e.g. capsule, streptolysin S and purogenic exotoxin B); however, deletion of this gene does not affect expression of hyaluronic acid capsule or severity of skin infection in mice.

A randomized controlled clinical trial of the serotonin type 3 receptor antagonist alosetron in women with diarrhea-predominant irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder seen in primary care practice. The symptoms of IBS, including abdominal pain, discomfort, and abnormal bowel function, may be modulated by activity of the serotonin type 3 receptor (5-HT(3)). The efficacy and tolerability of the 5-HT(3) receptor antagonist alosetron hydrochloride in nonconstipated female patients with IBS were evaluated in a double-blind, randomized, placebo-controlled trial.

METHODS

Patients received either 1 mg of alosetron hydrochloride (n = 309) or placebo (n = 317) twice daily for 12 weeks, followed by a 4-week posttreatment period. Adequate relief of IBS pain and discomfort was the primary end point. Secondary end points included improvements in urgency, stool frequency, stool consistency, incomplete evacuation, and bloating.

RESULTS

Seventy-one percent of patients were classified as having diarrhea-predominant IBS. Forty-three percent of alosetron-treated patients with diarrhea-predominant IBS reported adequate relief for all 3 months compared with 26% of placebo-treated patients (P<.001; percentage point difference = 17; 95% confidence interval, 8.0-25.4). Improvement with alosetron compared with placebo was observed by the end of the fourth week of treatment and persisted throughout the remainder of treatment. Alosetron significantly decreased urgency and stool frequency and caused firmer stools within 1 week of starting treatment. Effects were sustained throughout treatment and symptoms returned following treatment cessation. No significant improvement in the percentage of days with sense of incomplete evacuation or bloating was observed compared with placebo during the first month of treatment. Constipation was the most commonly reported adverse event.

CONCLUSION

Alosetron hydrochloride, 1 mg twice daily for 12 weeks, is effective in relieving pain and some bowel-related symptoms in diarrhea-predominant female patients with IBS.

Spontaneous mutations in the CsrRS two-component regulatory system of Streptococcus pyogenes result in enhanced virulence in a murine model of skin and soft tissue infection

CsrS/CsrR is a 2-component system in Streptococcus pyogenes that negatively regulates hyaluronic capsule and several exotoxins. To detect spontaneous mutations in csrRS, mucoid and large colony variants of M1 strain MGAS166 were isolated from experimental murine skin infections. By use of complementation with a csrRS(+) plasmid, relevant mutations were also detected in 7 of 12 human clinical isolates. The presence of spontaneous mutants in mouse infection was associated with larger, more necrotic lesions. Most spontaneous changes in CsrR resulted from single amino acid substitutions, whereas most csrS mutations were frameshift or nonsense mutations. In 2 instances, IS1548 insertions were found in csrS. Experimental inoculation of mixtures of wild-type (wt) and csrRS(-) bacteria yielded larger, more necrotic lesions than did either strain at twice the inoculum, which suggests that these variants may exhibit pathogenic synergy. Spontaneous emergence of csrRS(-) mutants in vivo enhances the virulence of wt bacteria and increases severity of murine skin infection.

An international collaborative study to establish the 1st international standard for HIV-1 RNA for use in nucleic acid-based techniques

Twenty-six laboratories from 10 different countries participated in a collaborative study to establish the 1st International Standard for HIV-1 RNA for use in nucleic acid-based techniques (NAT). Three candidate preparations were tested all based on genotype B viruses. The candidates were tested by each laboratory at a range of dilutions in four independent assays and the results collated and analysed statistically. All three candidates gave results that were tightly grouped, with little difference between the results from different laboratories or from the use of different assays. Studies of relative potency showed good agreement between laboratories. There were no significant differences between five commercial assay types, except that candidate XX showed a slightly lower potency compared to YY and ZZ with a single commercial assay. The reason for this was not established. Degradation studies showed that the freeze-dried preparations were stable at -20,4 and 20 degrees C for 26 weeks, the longest period studied, but that they became difficult to reconstitute after 3 weeks at 45 degrees C and 9 weeks at 37 degrees C. As a result of the study, the World Health Organisation (WHO) Expert Committee on Biological Standardisation (ECBS) established the preparation referred to as candidate YY (NIBSC Code No. 97/656) as the 1st International Standard for HIV-1 RNA for use with NAT with an assigned potency of 100000 International Units per vial.

An international collaborative study to establish a World Health Organization international standard for hepatitis B virus DNA nucleic acid amplification techniques

BACKGROUND AND OBJECTIVES

Twenty-two laboratories from nine countries participated in an international collaborative study to establish a World Health Organization (WHO) international standard for hepatitis B virus (HBV) DNA nucleic acid amplification techniques (NAT).

MATERIALS AND METHODS

Three samples, AA, BB (both of which were lyophilized) and CC (which was a liquid preparation), were analysed using several different NAT assays. The mean HBV DNA content of each sample was determined from the study.

RESULTS

Despite the range of assays (commercial and in-house) used by participants, there was good agreement among the overall mean 'equivalents'/ml obtained by the different assays, except for one laboratory (laboratory 4). The variation in estimates of log10 'equivalents'/ml was 1.75-1.25 for the three samples if results from laboratory 4 were excluded. The mean log10 'equivalents'/ml for all laboratories were 6.42 for sample AA, 6.30 for sample BB and 5.03 for sample CC (exclusion of results from laboratory 4 made little difference). The difference in titres between the two lyophilized samples (AA and BB) was not statistically significant but the titre of the frozen sample (CC) was significantly lower. Material AA (code 97/746) was accepted as the first WHO international standard for HBV DNA NAT assays and assigned a potency of 10(6) international units (IU)/ml.

CONCLUSIONS

The titres (genome equivalents/ml) of three HBV preparations were determined by several laboratories using different NAT assays. This study enabled the establishment of an international standard, 97/746, for HBV DNA NAT assays.

The HeartSmart Family Fun Pack: an evaluation of family-based intervention for cardiovascular risk reduction in children

In 1998, the Heart and Stroke Foundation launched the HeartSmart Family Fun Pack, a "user-friendly" resource to support family-based lifestyle changes among children age 6-12 years. Of 1,387 parents who completed a pre-intervention questionnaire, 300 (21%) were surveyed three months later. Comparisons of the pre- and post-intervention surveys show that the Family Fun Pack was effective in supporting healthy lifestyle changes (38% and 28% of families reported improvement in their child's nutrition and level of physical activity, respectively; 12% reported reduced passive smoking). Effectiveness was greatest among those families who self-identified themselves as being in what corresponds to the contemplation, preparation and action stages of change. This evaluation suggests that a relatively low-cost intervention can be effective in supporting positive lifestyle changes if targeted to families at specific points in the stages of change.

Phylogeny and life history evolution of the genus Chrysoritis within the Aphnaeini (Lepidoptera: Lycaenidae), inferred from mitochondrial cytochrome oxidase I sequences

Phylogenetic relationships among 26 South African species in the tribe Aphnaeini (Lepidoptera: Lycaenidae) were inferred from DNA characters of the mitochondrial gene cytochrome oxidase I (COI), using maximum-parsimony methods. The resulting phylogenetic estimate supports the systematic hypothesis made by Heath (1997, Metamorphosis, supplement 2), based on morphological characters, that at least three preexisting genera (Chrysoritis, Poecilmitis, and Oxychaeta) should be collapsed into the single monophyletic genus Chrysoritis. Two of the species groups described by Heath within Chrysoritis are also monophyletic, while one is paraphyletic and thus unsupported by the molecular data. Strong node support and skewed transition/transversion ratios suggest that two Chrysoritis clades contain synonymous species. Aphytophagy appears as a derived feeding strategy. Evolutionary patterns of ant association indicate lability at the level of ant genus, while association with different ant subfamilies may have played an ancestral and chemically mediated role in the diversification of South African aphnaeines.

Calibration of HCV working reagents for NAT assays against the HCV international standard. The Collaborative Study Group

BACKGROUND AND OBJECTIVES

Five HCV RNA reference reagents, the Paul Ehrlich Institut (PEI) reference 75, the National Institute for Biological Standards and Control (NIBSC) reagent 96/586, the Central Laboratory of the Netherlands Red Cross Blood Transfusion Service (CLB) Pelispy HCV RNA run control S2001, the Istituto Superiore di Sanità (ISS) reagent 0498 and the CBER panel member No. 1, were calibrated against the WHO International Standard, 96/790.

MATERIALS AND METHODS

The reference materials were calibrated in a collaborative study organised by NIBSC. Nineteen laboratories, using a range of qualitative and quantitative assays returned results.

RESULTS

The concentrations of the reagents were: 25,000 IU/ml for the PEI material, 710 IU/ml for the NIBSC material 96/586, 1,000 IU/ml for the CLB material, 1,700 IU/ml for the ISS material 0498 and 250 IU/ml for the CBER panel member No. 1.

CONCLUSIONS

The calibration of these five reference reagents for HCV RNA nucleic acid amplification technology (NAT) assays enables them to be used for standardisation and validation of assays. Such calibrants are essential for meeting the requirements of the European Medicinal Evaluation Agency (EMEA) for the testing of plasma pools and donations for HCV RNA for the release of blood products and the PEI requirements for the release testing of erythrocyte and thrombocyte concentrates.

Establishment of the first international standard for nucleic acid amplification technology (NAT) assays for HCV RNA. WHO Collaborative Study Group

BACKGROUND AND OBJECTIVES

The aims of this study were the establishment of a WHO International standard for HCV RNA for nucleic acid amplification technology (NAT) assays and the determination of the HCV RNA content of the candidate standard.

MATERIALS AND METHODS

Twenty-two laboratories evaluated three candidate materials (two lyophilised, AA and BB, which were derived from the same source and one a liquid preparation, CC). All samples were HCV genotype 1 with a concentration of approximately 10(5) genome equivalents/ml. The methods used included the Roche Amplicor assay (version 1), Chiron Quantiplex (bDNA) assay, Organon Teknika NASBA assay, Transcription Mediated assay and various in-house assays, using single or nested primers.

RESULTS

There was reasonable agreement between the overall mean NAT detectable units/ml obtained by the different assays except for some of the in-house assays using single primers which gave substantially lower estimates. These titres were 5.0 log10 for samples AA and BB and 4.6 log10 for sample CC.

CONCLUSIONS

Sample AA was accepted as the candidate standard and assigned a titre of 10(5) international units (IU)/ml. The International Standard consists of a batch of vials each containing 50,000 IU/vial. Preliminary studies indicated that the material is stable at +4 degrees C and +20 degrees C for up to 200 days.

The HeartSmart Family Fun Pack: an evaluation of family-based intervention for cardiovascular risk reduction in children

In 1998, the Heart and Stroke Foundation launched the HeartSmart Family Fun Pack, a "user-friendly" resource to support family-based lifestyle changes among children age 6-12 years. Of 1,387 parents who completed a pre-intervention questionnaire, 300 (21%) were surveyed three months later. Comparisons of the pre- and post-intervention surveys show that the Family Fun Pack was effective in supporting healthy lifestyle changes (38% and 28% of families reported improvement in their child's nutrition and level of physical activity, respectively; 12% reported reduced passive smoking). Effectiveness was greatest among those families who self-identified themselves as being in what corresponds to the contemplation, preparation and action stages of change. This evaluation suggests that a relatively low-cost intervention can be effective in supporting positive lifestyle changes if targeted to families at specific points in the stages of change.

Virulence gene regulation inside and outside

Much knowledge about microbial gene regulation and virulence is derived from genetic and biochemical studies done outside of hosts. The aim of this review is to correlate observations made in vitro and in vivo with two different bacterial pathogens in which the nature of regulated gene expression leading to virulence is quite different. The first is Vibrio cholerae, in which the concerted action of a complicated regulatory cascade involving several transcription activators leads ultimately to expression of cholera toxin and the toxin-coregulated pilus. The regulatory cascade is active in vivo and is also required for maintenance of V. cholerae in the intestinal tract during experimental infection. Nevertheless, specific signals predicted to be generated in vivo, such as bile and a temperature of 37 degrees C, have a severe down-modulating effect on activation of toxin and pilus expression. Another unusual aspect of gene regulation in this system is the role played by inner membrane proteins that activate transcription. Although the topology of these proteins suggests an appealing model for signal transduction leading to virulence gene expression, experimental evidence suggests that such a model may be simplistic. In Streptococcus pyogenes, capsule production is critical for virulence in an animal model of necrotizing skin infection. Yet capsule is apparently produced to high levels only from mutation in a two-component regulatory system, CsrR and CsrS. Thus it seems that in V. cholerae a complex regulatory pathway has evolved to control virulence by induction of gene expression in vivo, whereas in S. pyogenes at least one mode of pathogenicity is potentiated by the absence of regulation.

Early myeloid cells are high producers of nitric oxide upon CD40 plus IFN-gamma stimulation through a mechanism dependent on endogenous TNF-alpha and IL-1alpha

Bone marrow contains nonadherent low-density wheat germ agglutinin-positive (Fr3-WGA(+)) cells that release large amounts of NO and show natural suppressor activity if stimulated with activated T cells. We have assessed the involvement of CD40-derived signals in NO production and their cytokine requirements. Production of NO by Fr3-WGA(+) cells in co-culture with activated T cells is inhibited by a competing CD40 soluble fusion protein. Fr3-WGA(+) cells express the inducible NO synthase (iNOS) and release NO following CD40 plus IFN-gamma activation. Production of NO through CD40 is strictly dependent on endogenous TNF-alpha and / or IL-1alpha, since it is inhibited by neutralizing these cytokines or blocking the TNF receptor (p55). Both cytokines are transcribed when Fr3-WGA(+) cells are stimulated by CD40 signaling plus IFN-gamma, although TNF-alpha remains below detection limits in stimulated Fr3-WGA(+) cell cultures. Phenotypic studies combined with data on intracellular iNOS expression and cell sorting indicate that NO-producing cells are CD40, CD31 (ER-MP12), CD11b (Mac-1)low, ER-MP20 (Ly-6C) and Gr-1 (Ly-6G) positive, consistent with myeloid progenitors. The results point to early myeloid cells as an important cell source of NO once triggered by activated T cells through CD40 and IFN-gamma-derived signals, in a mechanism involving the production of TNF-alpha and / or IL-1alpha.

A double-blind, randomized, placebo-controlled dose-ranging study to evaluate the efficacy of alosetron in the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome is a common gastrointestinal disorder characterized by abdominal pain and discomfort and altered bowel habit. Antagonism at the 5-HT3 receptor may be of benefit in the treatment of irritable bowel syndrome.

AIMS

To evaluate the effect of 12 weeks of treatment with alosetron, a 5-HT3 receptor antagonist at doses of 0.1 mg b.d., 0.5 mg b.d. and 2 mg b.d. in irritable bowel syndrome patients.

METHODS

A double-blind, placebo-controlled, parallel-group study with a 2-week screening and a 12-week treatment period was conducted. A total of 462 patients (335 female) recorded details of the severity of their abdominal pain, and bowel function daily on a diary card throughout the study. At monthly clinic visits patients recorded the severity of their abdominal pain/discomfort and diarrhoea on a visual analogue scale.

RESULTS

In the total population and in the female subpopulation (but not in males) alosetron 2 mg b.d. significantly increased the proportion of pain-free days and decreased the visual analogue scale score for diarrhoea compared with placebo. Alosetron at doses of 0.5 mg b.d. and 2 mg b.d. led to a significant hardening of stool, and a reduction in stool frequency in the total population.

CONCLUSION

Alosetron at a dose of 2 mg b.d. is an effective treatment for female patients with irritable bowel syndrome.

Ophthalmomyiasis and nasal myiasis in New Zealand: a case series

We report three cases of ophthalmomyiasis in New Zealand, due to the larvae of Oestrus ovis. All three patients reported eye injury caused by a fly. The larvae were removed from the conjunctival sac without difficulty under local anaesthesia. Presenting ocular symptoms of foreign body sensation, irritation, redness and photophobia all resolved swiftly. Topical antibiotic and steroid eye drops were administered. All three patients also developed nasal symptoms such as sneezing, nasal discharge and epistaxis. Otolaryngology follow-up demonstrated nasal myiasis in two patients which was treated with nasal decongestants. In addition, all three patients were treated with ivermectin (Mectizan).

A two-component regulatory system, CsrR-CsrS, represses expression of three Streptococcus pyogenes virulence factors, hyaluronic acid capsule, streptolysin S, and pyrogenic exotoxin B

Certain Tn916 insertions in the chromosome of an M1-type, nonmucoid Streptococcus pyogenes isolate (MGAS166) were previously shown to result in stable mucoidy with increased expression of the capsular synthetic genes. The transposon insertions in these strains are directly upstream of an apparent operon encoding a two-component regulatory system, designated csrR-csrS. Compared with MGAS166, these mucoid mutants are more hemolytic and cause significantly more tissue damage in a murine model of skin infection. To extend these observations, we constructed an in-frame deletion in the gene encoding the response regulator, csrR, and we evaluated the expression of other known S. pyogenes virulence factors. We discovered that csrR mutants have enhanced transcription of sagA, a gene associated with streptolysin S (SLS) and speB, the gene encoding pyrogenic exotoxin B (SpeB). The mutants also express substantially higher SLS activity and SpeB antigen in late-exponential-phase cultures. There is no change in expression of emm, scpA, sic, or cpa (genes encoding other S. pyogenes virulence factors). CsrR- strains but not the wild-type parental strain produce necrotizing lesions in a mouse model of subcutaneous infection. A double mutant with deletions in both csrR and the capsular synthesis genes caused fewer and smaller necrotic skin lesions than the csrR mutants. However, this nonmucoid csrR strain was more likely than the wild type to yield necrotic lesions, suggesting that mucoidy contributes to virulence in this model of infection but that there are other csrR-regulated factors involved in the production of necrotic lesions.