Specialist multidisciplinary input maximises rare disease diagnoses from whole genome sequencing

Diagnostic whole genome sequencing (WGS) is increasingly used in rare diseases. However, standard, semi-automated WGS analysis may overlook diagnoses in complex disorders. Here, we show that specialist multidisciplinary analysis of WGS, following an initial 'no primary findings' (NPF) report, improves diagnostic rates and alters management. We undertook WGS in 102 adults with diagnostically challenging primary mitochondrial disease phenotypes. NPF cases were reviewed by a genomic medicine team, thus enabling bespoke informatic approaches, co-ordinated phenotypic validation, and functional work. We enhanced the diagnostic rate from 16.7% to 31.4%, with management implications for all new diagnoses, and detected strong candidate disease-causing variants in a further 3.9% of patients. This approach presents a standardised model of care that supports mainstream clinicians and enhances diagnostic equity for complex disorders, thereby facilitating access to the potential benefits of genomic healthcare. This research was made possible through access to the data and findings generated by the 100,000 Genomes Project: http://www.genomicsengland.co.uk .

Genome sequencing reveals underdiagnosis of primary ciliary dyskinesia in bronchiectasis

BACKGROUND

Bronchiectasis can result from infectious, genetic, immunological and allergic causes. 60-80% of cases are idiopathic, but a well-recognised genetic cause is the motile ciliopathy, primary ciliary dyskinesia (PCD). Diagnosis of PCD has management implications including addressing comorbidities, implementing genetic and fertility counselling and future access to PCD-specific treatments. Diagnostic testing can be complex; however, PCD genetic testing is moving rapidly from research into clinical diagnostics and would confirm the cause of bronchiectasis.

METHODS

This observational study used genetic data from severe bronchiectasis patients recruited to the UK 100,000 Genomes Project and patients referred for gene panel testing within a tertiary respiratory hospital. Patients referred for genetic testing due to clinical suspicion of PCD were excluded from both analyses. Data were accessed from the British Thoracic Society audit, to investigate whether motile ciliopathies are underdiagnosed in people with bronchiectasis in the UK.

RESULTS

Pathogenic or likely pathogenic variants were identified in motile ciliopathy genes in 17 (12%) out of 142 individuals by whole-genome sequencing. Similarly, in a single centre with access to pathological diagnostic facilities, 5-10% of patients received a PCD diagnosis by gene panel, often linked to normal/inconclusive nasal nitric oxide and cilia functional test results. In 4898 audited patients with bronchiectasis, <2% were tested for PCD and <1% received genetic testing.

CONCLUSIONS

PCD is underdiagnosed as a cause of bronchiectasis. Increased uptake of genetic testing may help to identify bronchiectasis due to motile ciliopathies and ensure appropriate management.

Wavelength-tuneable laser emission from stretchable chiral nematic liquid crystal gels via in situ photopolymerization

We describe a technique for creating multi-coloured liquid crystalline laser gels which may be selectively and reversibly wavelength-tuned by applying a mechanical strain.

Spontaneous emission from radiative chiral nematic liquid crystals at the photonic band-gap edge: an investigation into the role of the density of photon states near resonance

In this article, we investigate the spontaneous emission properties of radiating molecules embedded in a chiral nematic liquid crystal, under the assumption that the electronic transition frequency is close to the photonic edge mode of the structure, i.e., at resonance. We take into account the transition broadening and the decay of electromagnetic field modes supported by the so-called "mirrorless"cavity. We employ the Jaynes-Cummings Hamiltonian to describe the electron interaction with the electromagnetic field, focusing on the mode with the diffracting polarization in the chiral nematic layer. As known in these structures, the density of photon states, calculated via the Wigner method, has distinct peaks on either side of the photonic band gap, which manifests itself as a considerable modification of the emission spectrum. We demonstrate that, near resonance, there are notable differences between the behavior of the density of states and the spontaneous emission profile of these structures. In addition, we examine in some detail the case of the logarithmic peak exhibited in the density of states in two-dimensional photonic structures and obtain analytic relations for the Lamb shift and the broadening of the atomic transition in the emission spectrum. The dynamical behavior of the atom-field system is described by a system of two first-order differential equations, solved using the Green's-function method and the Fourier transform. The emission spectra are then calculated and compared with experimental data.

Spectrum, and clinical and functional implications of UNC13D mutations in familial haemophagocytic lymphohistiocytosis

OBJECTIVE

Familial haemophagocytic lymphohistiocytosis (FHL) is a fatal disorder of immune dysregulation with defective cytotoxic lymphocyte function. Disease-causing mutations have been identified in the genes encoding perforin (PRF1), syntaxin-11 (STX11), and Munc13-4 (UNC13D). We screened for UNC13D mutations and studied clinical and functional implications of such mutations in a well defined patient cohort.

METHODS

Sequencing of UNC13D was performed in 38 FHL patients from 34 FHL families in which PRF1 and STX11 mutations had been excluded.

RESULTS

We identified six different mutations affecting altogether 9/38 individuals (24%) in 6/34 (18%) unrelated PRF1/STX11-negative families. Four novel mutations were revealed; two homozygous nonsense mutations (R83X and W382X), one splice mutation (exon 28), and one missense mutation (R928P). In addition, two known mutations were identified (R214X and a deletion resulting in a frame-shift starting at codon 782). There was considerable variation in the age at diagnosis, ranging from time of birth to 14 years (median 69 days). Three of nine patients (33%) developed central nervous system (CNS) symptoms. Natural killer (NK) cell activity was impaired in all four patients studied. Defective cytotoxic lymphocyte degranulation was evident in the two patients investigated, more pronounced in the patient with onset during infancy than in the patient with adolescent onset.

CONCLUSIONS

Biallelic UNC13D mutations were found in 18% of the PRF1/STX11-negative FHL families. Impairment of NK cell degranulation was less pronounced in a patient with adolescent onset. FHL should be considered not only in infants but also in adolescents, and possibly young adults, presenting with fever, splenomegaly, cytopenia, hyperferritinaemia, and/or CNS symptoms.

Use of nonprescription topical steroids: patients' experiences

BACKGROUND

Topical steroids became available, without prescription, in the U.K. in 1987, with hydrocortisone 1% cream first being licensed for irritant contact dermatitis and reactions to insect bites. Since then the number of indications for nonprescription hydrocortisone use has increased and clobetasone has also become available as an over-the-counter (OTC) medicine. Little has been reported about how OTC steroids are used by community pharmacy clients.

OBJECTIVES

We determined how OTC topical steroids are applied by patients, their demographic profile, the products used and the conditions treated, how frequently products were applied and how regularly purchased. The extent to which off-label use takes place was explored.

METHODS

A patient-completed questionnaire study was used in 100 branches of a national pharmacy in Great Britain.

RESULTS

Questionnaires were completed and returned by 315 clients (16%). Eczema (192 cases, 61%) and dermatitis (66 cases, 21%) were the conditions most frequently treated. Nottingham Eczema Severity Scores calculated for 228 eczema and dermatitis sufferers shows that 164 patients (72%) had mild eczema. Those with more severe eczema were more likely to use clobetasone than hydrocortisone. The use of topical steroids outside OTC marketing authorization guidelines was widespread; however, no patient reported any adverse effects or deterioration in condition following steroid use.

CONCLUSIONS

OTC topical steroids are used mainly to treat eczema and dermatitis. Almost 50% of users treating these conditions exceed the limits of the rather restrictive OTC marketing authorization. Clinicians should be aware of the potential for adverse effects as a result of patients self-medicating with hydrocortisone or clobetasone for an extended period.

Agent-Based Computational Modeling of Wounded Epithelial Cell Monolayers

Computational modeling of biological systems, or in silico biology, is an emerging tool for understanding structure and order in biological tissues. Computational models of the behavior of epithelial cells in monolayer cell culture have been developed and used to predict the healing characteristics of scratch wounds made to urothelial cell cultures maintained in low- and physiological [Ca2+] environments. Both computational models and in vitro experiments demonstrated that in low exogenous [Ca2+], the closure of 500-microm scratch wounds was achieved primarily by cell migration into the denuded area. The wound healing rate in low (0.09 mM) [Ca2+] was approximately twice as rapid as in physiological (2 mM) [Ca2+]. Computational modeling predicted that in cell cultures that are actively proliferating, no increase in the fraction of cells in the S-phase would be expected, and this conclusion was supported experimentally in vitro by bromodeoxyuridine incorporation assay. We have demonstrated that a simple rule-based model of cell behavior, incorporating rules relating to contact inhibition of proliferation and migration, is sufficient to qualitatively predict the calcium-dependent pattern of wound closure observed in vitro. Differences between the in vitro and in silico models suggest a role for wound-induced signaling events in urothelial cell cultures.

The epitheliome: agent-based modelling of the social behaviour of cells

We have developed a new computational modelling paradigm for predicting the emergent behaviour resulting from the interaction of cells in epithelial tissue. As proof-of-concept, an agent-based model, in which there is a one-to-one correspondence between biological cells and software agents, has been coupled to a simple physical model. Behaviour of the computational model is compared with the growth characteristics of epithelial cells in monolayer culture, using growth media with low and physiological calcium concentrations. Results show a qualitative fit between the growth characteristics produced by the simulation and the in vitro cell models.

Selection of mutant CHO cells with constitutive activation of the HIF system and inactivation of the von Hippel-Lindau tumor suppressor

Hypoxia-inducible factor (HIF) mediates a widespread transcriptional response to hypoxia through binding to cis-acting DNA sequences termed hypoxia response elements (HREs). Activity of the transcriptional complex is suppressed in the presence of oxygen by processes that include the targeting of HIF-alpha subunits for ubiquitin-mediated proteolysis. To provide further insights into these processes we constructed Chinese hamster ovary (CHO) cells bearing stably integrated plasmids that expressed HRE-linked surface antigens and used these cells in genetic screens for mutants that demonstrated constitutive up-regulation of HRE activity. From mutagenized cultures, clones were isolated that demonstrated up-regulation of HRE activity and increased HIF-1alpha protein levels in normoxic culture. Transfection and cell fusion studies suggested that these cells possess recessive defects that affect one or more pathways involved in HIF-alpha proteolysis. Two lines were demonstrated to harbor truncating mutations in the von Hippel-Lindau (VHL) tumor suppressor gene. In these cells, defects in ubiquitylation of exogenous human HIF-1alpha in vitro could be complemented by wild type pVHL, and re-expression of a wild type VHL gene restored a normal pattern of HIF/HRE activity, demonstrating the critical dependence of HIF regulation on pVHL in CHO cells. In contrast, other mutant cells had no demonstrable mutation in the VHL gene, and ubiquitylated exogenous HIF-1alpha normally, suggesting that they contain defects at other points in the oxygen-regulated processing of HIF-alpha subunits.

Surface electromyography using electrode arrays: a study of motor neuron disease

The use of electromyography (EMG) is limited, particularly in the investigation of children, by the invasive nature of needle electrodes. Surface electrode techniques are an attractive alternative but the detected signals are greatly influenced by volume conductor effects, thus making their interpretation problematic. Using finite element analysis we investigated the relationship between surface potential distribution and motor unit depth, incorporating anisotropic conductivity to model muscle tissue and a range of subcutaneous fat thicknesses. The modeling results were used to analyze data recorded with a 16-channel surface electrode array, from 10 normals subjects and 12 patients with motor neuron disease. Differences in the motor units between the two groups were statistically significant (P < 0.01) and are consistent with reinnervation and increased motor unit territory in the patient group. This noninvasive technique shows promise as a more acceptable alternative to the use of conventional needle electrodes for neurophysiological investigations.

CYP2D6 and CYP2C19 genotypes of patients with terodiline cardiotoxicity identified through the yellow card system

AIMS

Terodiline has concentration dependent QT prolonging effects and thus the potential for cardiotoxicity. Pharmacogenetic variation in terodiline metabolism could be responsible for cardiotoxicity. We sought to determine whether CYP2D6 (debrisoquine hydroxylase) or CYP2C19 (S-mephenytoin hydroxylase) status is a risk factor for terodiline cardiotoxicity.

METHODS

Using the UK Yellow Card scheme to identify patients, blood samples were obtained from eight patients who survived ventricular tachycardia or torsades de pointes suspected to be due to terodiline, for determination of CYP2D6 and CYP2C19 genotypes. Genotype prevalence was compared with that in published general population groups.

RESULTS

One patient was a CYP2D6 poor metaboliser (CYP2D6*4 homozygous) and a second was heterozygous for CYP2D6*4, a slightly lower frequency for these genotypes compared with the general population (P = 0.31). In the case of CYP2C19, one patient was a poor metaboliser and four were heterozygous for the variant CYP2C19*2 allele, compared with general population frequencies of 2% and 23%, respectively (P = 0.035).

CONCLUSIONS

These findings suggest that debrisoquine poor metaboliser status is not primarily responsible for terodiline cardiotoxicity. However, possession of the CYP2C19*2 allele appears to contribute to adverse cardiac reactions to terodiline. The present study demonstrates the feasibility of using spontaneous adverse drug reaction reporting schemes to determine the contribution of genotype for metabolizing enzymes to uncommon adverse drug reactions.

Oxidative stress in humans during work at moderate altitude

Increased oxidative stress has been associated with work at high altitude; however, it is not known whether oxidative stress is a significant problem at moderate altitudes. The oxidative stress indicators, breath pentane (BP), 8-hydroxydeoxyguanosine (8-OHdG), oxygen radical absorption capacity (ORAC), 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), and lipid peroxides (LPO) were measured in breath, blood and urine samples of U.S. Marines engaged in moderate altitude ( approximately 3000 m) cold weather field training. The test subjects were divided into a placebo and four antioxidant supplement groups (n = 15/group) and received the following supplements for 28 d: 1) vitamin E, 440 alpha-tocopherol equivalents (alpha-TE); 2) vitamin A, 2000 retinol equivalents (RE) of beta-carotene; 3) vitamin C, 500 mg ascorbic acid; 4) a mixture of 440 alpha-TE, 2000 RE of beta-carotene, 500 mg ascorbic acid, 100 microg selenium and 30 mg zinc daily. Strenuous work ( approximately 23 MJ/d) in cold weather at moderate altitude was accompanied by increases in several indicators of oxidative stress that were not effectively controlled by conventional antioxidant supplements. The group receiving the antioxidant mixture exhibited lower BP (P < 0. 05) compared with those receiving single antioxidant supplements; however, not all markers of oxidative stress responded like BP. Because these markers did not respond in the same manner, it is important to include markers from more than one source to assess the effect of supplemental dietary antioxidants.

Effect of antioxidant supplementation on urine and blood markers of oxidative stress during extended moderate-altitude training

OBJECTIVE

To investigate the increase in oxidative stress during work at moderate altitudes due to additional energy expenditure, tissue anoxia, and UV light exposure.

METHODS

Thirty US Marine Corps volunteers were divided into placebo (P) and antioxidant supplement (S) groups and tested for markers of oxidative stress before (t0), at the midpoint of (t1), and after (t2) 14 days of winter training at a moderate altitude (approximately 2700 m). The antioxidant supplement consisted of a daily dose of 20,000 IU beta-carotene, 400 IU vitamin E, 500 mg vitamin C, 100 micrograms selenium, and 30 mg zinc. The following markers of oxidative stress were measured: urine thiobarbituric acid reactive substances (TBARSs), urine hydroxynonenal (HNE), urine 8-hydrodeoxyguanosine (8-OHdG), plasma total peroxyl radical trapping potential (TRAP), and plasma lipid hydroperoxides (LPOs). Urine was collected on a 24-hr basis at t0, t1, and t2; blood samples were collected at t0 and t2.

RESULTS

P group LPOs increased 30% (p < 0.05) between t0 and t2, whereas S group LPOs did not increase. Both groups exhibited significant increases in urine TBARSs, HNE, and 8-OHdG by t2. Urine TBARSs, HNE, and 8-OHdG increased between t0 and t1 in both groups, with the greater increase in the S group. The conflicting results between the plasma and urine markers of oxidative stress may be due to a time-phase relationship.

CONCLUSIONS

The results of this study suggest that work in a moderate-altitude cold-weather environment is accompanied by increased oxidative stress, despite relatively high intakes of dietary and supplemental antioxidants.

Secondary heterotypic versus homotypic infection by Coxsackie B group viruses: impact on early and late histopathological lesions and virus genome prominence

The impact of prior exposure to a different or identical strain of Coxsackievirus B (CVB) on murine CVB myocarditis was studied using a susceptible murine host (A/J[H-2a]) and myocarditic CVB3 or avirulent CVB2 as primary or secondary infectants. The effects of secondary heterotypic infection (CVB2 followed by CVB3) and homotypic infection (CVB3 followed by CVB3) 28 days after primary inoculation, versus CVB2 or CVB3 alone, on injury and viral genomic replication, both early (day 7) and late (days 28 and 56), were evaluated. After the primary infection by CVB2, trivial viral RNA was present in the heart and other organs, and a substantial positivity was observed with CVB3 infection. Seven days after secondary heterotypic (CVB2-CVB3) infection, the quantity of CVB genome in heart, pancreas, liver, and spleen was increased compared with the virus genome in the CVB3-CVB3 group and in the group with primary CVB3 infection alone. This phenomenon was seen in the heart and spleen up to day 28 postsecondary infection. Tissue inflammation and necrosis in heart and pancreas were prominent 7 days postsecondary infection with CVB2-CVB3 and correlated well with an increased quantity of CVB genome. Virus genome was present in heart and spleen 28 days after CVB3 infection alone. Serum CVB3 neutralization titer was increased to 1:128 in CVB2-CVB3 group at days 7 and 28 postsecondary infection, and serum completely neutralized cytopathological effects of CVB3 in the CVB3-CVB3 group at day 7 and 28 postsecondary infection. Our results indicate that secondary heterotypic infection by CVB causes increased injury, inflammation, and CVB replication in target organs such as the heart and pancreas, as well as in immune compartments like the spleen. Compared with CVB3 alone, the intense inflammatory infiltriate in the CVB2-CVB3 group is as not due solely to postviral sensitization of the immune system, but rather to the inability of the host to eradicate the virus.

Induction of endothelial PAS domain protein-1 by hypoxia: characterization and comparison with hypoxia-inducible factor-1alpha

Hypoxia results in adaptive changes in the transcription of a range of genes including erythropoietin. An important mediator is hypoxia-inducible factor-1 (HIF-1), a DNA binding complex shown to contain at least two basic helix-loop-helix PAS-domain (bHLH-PAS) proteins, HIF-1alpha and aryl hydrocarbon nuclear receptor translocator (ARNT). In response to hypoxia, HIF-1alpha is activated and accumulates rapidly in the cell. Endothelial PAS domain protein 1 (EPAS-1) is a recently identified bHLH-PAS protein with 48% identity to HIF-1alpha, raising the question of its role in responses to hypoxia. We developed specific antibodies and studied expression and regulation of EPAS-1 mRNA and protein across a range of human cell lines. EPAS-1 was widely expressed, and strongly induced by hypoxia at the level of protein but not mRNA. Comparison of the effect of a range of activating and inhibitory stimuli showed striking similarities in the EPAS-1 and HIF-1alpha responses. Although major differences were observed in the abundance of EPAS-1 and HIF-1alpha in different cell types, differences in the inducible response were subtle with EPAS-1 protein being slightly more evident in normoxic and mildly hypoxic cells. Functional studies in a mutant cell line (Ka13) expressing neither HIF-1alpha nor EPAS-1 confirmed that both proteins interact with hypoxically responsive targets, but suggest target specificity with greater EPAS-1 transactivation (relative to HIF-1alpha transactivation) of the VEGF promoter than the LDH-A promoter.

Mortality and morbidity of workers exposed to acrylonitrile in fiber production

This study assessed the risk of cancer mortality and incidence among 2559 employees exposed to acrylonitrile in the production of Orlon at 2 plants in 1944-1991. Latency, duration of exposure, highest level of exposure ever experienced, and cumulative exposure were used as indicators of exposure. The average duration of exposure for the workers was 7.6 years with an average cumulative exposure of 57.6 ppm-years. Overall mortality was lower than expected in a comparison with the United States population and all DuPont employees [454 deaths, standardized mortality ratios (SMR) of 69 and 91, respectively)]. All the cancer death ratios were lower than expected in a similar comparison. The SMR values for specific sites did not differ significantly from the expected values. Mortality from all cancers and from prostate, respiratory, and digestive cancer did not show any significantly associated increases or a consistent pattern suggestive of a dose-response. The cancer morbidity patterns were similarly unremarkable.

Selection and analysis of a mutant cell line defective in the hypoxia-inducible factor-1 alpha-subunit (HIF-1alpha). Characterization of hif-1alpha-dependent and -independent hypoxia-inducible gene expression

Hypoxia-inducible expression has been demonstrated for many groups of mammalian genes, and studies of transcriptional control have revealed the existence of hypoxia-responsive elements (HREs) in the cis-acting sequences of several of these genes. These sequences generally contain one or more binding sites for a heterodimeric DNA binding complex termed hypoxia-inducible factor-1 (HIF-1). To analyze this response further, Chinese hamster ovary cells were stably transfected with plasmids bearing HREs linked to genes encoding immunoselectable cell surface markers, and clones that showed reduced or absent hypoxia-inducible marker expression were selected from a mutagenized culture of cells. Analysis of these cells revealed several clones with transacting defects in HRE activation, and in one the defect was identified as a failure to express the alpha-subunit of HIF-1. Comparison of hypoxia-inducible gene expression in wild type, HIF-1alpha-defective, and HIF-1alpha-complemented cells revealed two types of response. For some genes (e.g. glucose transporter-1), hypoxia-inducible expression was critically dependent on HIF-1alpha, whereas for other genes (e.g. heme oxygenase-1) hypoxia-inducible expression appeared largely independent of the expression of HIF-1alpha. These experiments show the utility of mutagenesis and selection of mutant cells in the analysis of mammalian transcriptional responses to hypoxia and demonstrate the operation of HIF-1alpha-dependent and HIF-1alpha-independent pathways of hypoxia-inducible gene expression in Chinese hamster ovary cells.

Hypoxia response elements

Hypoxia-inducible factor-1 (HIF-1) has been shown to mediate the transcriptional activation of its target genes in response to oxygen concentration, most likely via a pathway involving a specific oxygen sensor. Molecular cloning of HIF-1 has shown that this widely expressed, DNA binding transcription factor is a heterodimer of two proteins, HIF-1 alpha and HIF-1 beta. A major control of HIF-1 activity by oxygen tension is achieved by changes in the level of the HIF-1 alpha subunit, which complexes with the constitutively expressed HIF-1 beta subunit. Such changes in HIF-1 alpha abundance occur via regulated stability, probably involving proteolysis, rather than at the level of transcription or translation. Further analysis has shown the existence of two separate regulatory domains in the C-terminus of the alpha subunit. Thus, a mechanism of oxygen-regulated HIF-1 activation is proposed, which involves the operation of one inducible domain being amplified by changes in protein level conferred by a second regulatory domain. Evidence for a critical role of HIF-1 in the response of diverse target genes involved in cellular growth and metabolism comes from studies on cultured, mutant mouse cells that lack a functional HIF-1 beta subunit. Furthermore, studies on tumor xenografts derived from the mutant and wild-type cells show that HIF-1 is activated in vivo, and has major effects on gene expression in response to tumor hypoxia. Thus, HIF-1 is a critical component of the oxygen-signaling pathway, and is a prime candidate regulator molecule for the role of coordinating vascular oxygen supply with cellular growth and energy metabolism.

Severe cystitis associated with tiaprofenic acid

OBJECTIVE

To review the UK spontaneous reports of urinary disorders associated with tiaprofenic acid and other non-steroidal anti-inflammatory drugs (NSAIDs) and put them into context of the usage of these preparations in the UK.

METHODS

Suspected adverse drug reaction (ADR) reports of urinary disorders associated with tiaprofenic acid and other NSAIDs received by the UKs spontaneous ADR reporting scheme were analysed.

RESULTS

Between 1982, when tiaprofenic acid was introduced in the UK, and August 1994, 69 cases of cystitis were reported, with a further 32 reports describing related urinary symptoms including frequency, dysuria and haematuria. Only eight cases of cystitis were reported for all other NSAIDs. The duration of treatment with tiaprofenic acid before the onset of urinary symptoms varied markedly (range 2 days to > 3 years). In patients in whom a drug-induced cause was suspected and the drug was stopped promptly, recovery usually occurred within weeks. However, many patients continued on long-term treatment with tiaprofenic acid and underwent extensive investigations to determine the cause of their urinary symptoms. On cystoscopy and biopsy, the findings were similar to interstitial cystitis. Most patients with chronic cystitis recovered after withdrawal of tiaprofenic acid, but some patients had surgery before the drug was stopped.

CONCLUSION

Tiaprofenic acid can cause severe cystitis. These reports highlight the importance of taking a full drug history in patients with unexplained chronic cystitis. Tiaprofenic acid should be stopped immediately in all patients developing urinary symptoms.

A comparison of the post-marketing safety of four selective serotonin re-uptake inhibitors including the investigation of symptoms occurring on withdrawal

1. We have addressed the question of whether there is a 'serotonin withdrawal syndrome' by analysis of spontaneous reports of suspected adverse drug reactions (ADRs) associated with four SSRIs. A comparison of the post-marketing safety profiles of the four SSRIs has also been made. 2. The UK database of ADRs was examined for reactions associated with fluoxetine, fluvoxamine, paroxetine and sertraline. The safety profiles of the four SSRIs were similar. However, withdrawal reactions with paroxetine constitute a greater proportion of reports (5.1%) than with the other SSRIs (0.06-0.9%). They have been reported more often with paroxetine (0.3 reports per thousand prescriptions) than with sertraline and fluvoxamine (0.03), and least often with fluoxetine (0.002). 3. Descriptions of withdrawal reactions received and further details of 217 reports of withdrawal reaction with paroxetine obtained by mailing a questionnaire to the reporting doctor were examined. Withdrawal symptoms were diverse but most commonly comprised dizziness, paraesthesia, tremor, anxiety, nausea and palpitation. They usually occurred after 2 days and lasted for an average of 10 days. There was no evidence of a physical drug dependency syndrome. 4. Symptoms different from the previous depressive illness occur after discontinuing an SSRI, and are reported most often with paroxetine. Paroxetine is the most pharmacologically specific of the SSRIs, but it is not clear whether the reactions constitute a 'serotonin withdrawal syndrome'.

The autopsy. Simple thoughts about the public needs and how to address them

Dialogue regarding the autopsy has been sustained largely by medical students and professionals, and by families of deceased patients. Exclusion of the general public may represent a significant reason for the inexorable decline of autopsy rates and politicoeconomic support. Sensitivity to public concerns regarding the autopsy process carries far-reaching moral and educational significance. A better understanding of the social value of the autopsy will help to ensure its survival in a climate of ever-tightening health-care budgets. Emphasis must be placed on integrating the autopsy process, from the initial request, performance and post-autopsy follow-up with families, to the diagnostic, pathobiologic and epidemiologic interpretation of the results obtained. Opportunities for investigating cause of death currently lie primarily in animal models or in forensic postmortem material where the cause of death is frequently known. Public awareness of the autopsy's special role in the setting of natural and unexplained death is essential if the autopsy is to be retained as a key tool in understanding human disease.

The role of the aryl hydrocarbon receptor nuclear translocator (ARNT) in hypoxic induction of gene expression. Studies in ARNT-deficient cells

Hypoxia-inducible factor-1 (HIF-1), a DNA-binding complex implicated in the regulation of gene expression by oxygen, has been shown to consist of a heterodimer of two basic helix-loop-helix Per-AHR-ARNT-Sim (PAS) proteins, HIF-1alpha, and HIF-1beta. One partner, HIF-1beta, had been recognized previously as the aryl hydrocarbon receptor nuclear translocator (ARNT), an essential component of the xenobiotic response. In the present work, ARNT-deficient mutant cells, originally derived from the mouse hepatoma line Hepa1c1c7, have been used to analyze the role of ARNT/HIF-1beta in oxygen-regulated gene expression. Two stimuli were examined: hypoxia itself and desferrioxamine, an iron-chelating agent that also activates HIF-1. Induction of the DNA binding and transcriptional activity of HIF-1 was absent in the mutant cells, indicating an essential role for ARNT/HIF-1beta. Analysis of deleted ARNT/HIF-1beta genes indicated that the basic, helix-loop-helix, and PAS domains, but not the amino or carboxyl termini, were necessary for function in the response to hypoxia. Comparison of gene expression in wild type and mutant cells demonstrated the critical importance of ARNT/HIF-1beta in the hypoxic induction of a wide variety of genes. Nevertheless, for some genes a reduced response to hypoxia and desferrioxamine persisted in these mutant cells, clearly distinguishing ARNT/HIF-1beta-dependent and ARNT/HIF-1beta-independent mechanisms of gene activation by both these stimuli.

Bacterial adhesion to dental amalgam and three resin composites

OBJECTIVES

The ability of three oral bacteria to adhere to hydrophobic amalgam (water contact angle 60 degrees) and hydrophobic resin composites (Prisma-AP.H 56 degrees. Herculite XRV 82 degrees and Z100 89 degrees) was compared using an in vitro assay.

METHODS AND RESULTS

Following preincubation of the materials with human saliva, X-ray photoelectron spectroscopy showed the surfaces to adsorb carbon and nitrogen-containing compounds in a conditioning film that appeared to block the detection of Na and others in 2100 resin. Hg and Ag in amalgam, Si and Zn in Prisma AP.H resin and Ag and Na in Herculite resin. The precoating of the substrata by a proteinaceous conditioning film led to decreased binding of viable cells of Streptococcus sanguis CH3, Streptococcus salivarius HB and Actinomyces viscosus WG as compared with the adhesion to bare composites. With and without salivary coating, there was a correlation between increased bacterial hydrophobicity and increased retention on the substrata. However, there was no statistical difference in binding to the amalgam compared with the resin composites. In vitro studies showed that the bacteria autoaggregated in the presence of saliva.

CONCLUSION

The results indicate the potential ability of normal oral flora to colonize resin composite.

Serum levels of circulating anodic antigen and circulating cathodic antigen detected in mice infected with Schistosoma japonicum or S. mansoni

Serum concentrations of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were studied in mice infected with either Schistosoma japonicum or S. mansoni cercariae. Sera from uninfected mice were negative for both antigens. CAA was detectable in the S. japonicum-infected mice as early as at 2 weeks post-infection (p.i.), and levels were higher in these animals than in the S. mansoni-infected group during the full study period. At the moment of perfusion, 10 weeks p.i., a median of 9 and 29 worms, respectively, were recovered from the S. japonicum- and S. mansoni-infected mice, and the median CAA levels were 326 and 27 ng/ml, respectively. In contrast, CCA levels were much lower in the S. japonicum-infected group (27 ng/ml) as compared with the S. mansoni-infected mice (282 ng/ml). These results suggest an important difference between S. japonicum and S. mansoni infections in CAA and CCA production and/or clearance and indicate a significant role for CAA in the diagnosis of human schistosomiasis japonicum.

Attitudinal survey of adverse drug reaction reporting by medical practitioners in the United Kingdom

1. Attitudes of doctors to the Committee on Safety of Medicines' (CSM) adverse drug reaction (ADR) reporting scheme were investigated in order to assess their understanding of the purposes of the scheme and to identify reasons for failing to report suspected adverse drug reactions. 2. A postal questionnaire and letter of invitation were sent to 500 doctors who were randomly selected from the 1992 Medical Directory. A reminder letter and a second copy of the questionnaire were sent to non-responders after 4 weeks. 3. 284 (57%) responded to the questionnaire. Of these, 179 (63%) stated that they had previously reported an ADR to the CSM or a pharmaceutical manufacturer. 77% of general practitioners stated that they had reported one or more ADRs compared with 55% of hospital doctors. 4. Reasons for under-reporting included lack of time, lack of report forms and the misconception that absolute confidence in the diagnosis of an adverse reaction was important in the decision to send in a report. 5. An investigation of seven commonly proposed reasons for under-reporting showed that on the whole they did not apply. 6. Most doctors knew the types of reactions that the Committee on Safety of Medicines seeks reports for but only 38% knew the precise meaning of the Committee on Safety of Medicines' black triangle symbol. There also seemed to be confusion about some of the purposes of the adverse drug reaction reporting scheme. 7. The number of reporting doctors is much higher than has previously been estimated.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors for calculus formation in patients with renal transplants

OBJECTIVE

To investigate the risk factors for stone formation in patients with functioning renal transplants in whom renal calculi develop.

PATIENTS AND METHODS

Renal calculi developed in six of 178 patients with functioning renal transplants under current review, an incidence of 3%. Risk factors for stone formation were investigated in five of these patients and compared with a randomly selected control group of 41 transplant patients with no stone problems.

RESULTS

Patients with transplant calculi typically passed smaller volumes of significantly more concentrated and alkaline urine with greater urinary excretion of uric acid (P < 0.05). Urine calcium excretion was also increased. Crystalluria was present in three of five stone formers compared with two of 25 controls. Overall, metabolic abnormalities included hypocitraturia (75%), hyperparathyroidism (36%), hypophosphataemia (24%) and hypercalcaemia (10%). Urinary infection was common (50%) and urinary output of magnesium and phosphate was at the lower end of normal for all patients.

CONCLUSION

These results suggest a multifactorial aetiology for stone formation in renal transplant recipients. Approaches to prevention and management are discussed.

Review of company postmarketing surveillance studies

OBJECTIVES

To review postmarketing surveillance studies sponsored by the pharmaceutical industry since the introduction of voluntary guidelines in 1987 and to evaluate their contribution to monitoring drug safety.

DESIGN

Retrospective analysis of the information submitted to the Medicines Control Agency on postmarketing surveillance studies.

SETTING

United Kingdom.

MAIN OUTCOME MEASURES

Study designs, projected and actual sample sizes, provision of interim and final reports, number of suspected serious adverse reactions reported, identification of new drug safety hazards.

RESULTS

31 studies had been conducted under the guidelines, of which 27 were prospective and four retrospective. Nine studies had at least one comparator group, the remainder were uncontrolled. The median projected sample size for the studies was 5600 patients. Only five studies had achieved at least 75% of the projected sample size. 11 studies had been abandoned, predominantly because of difficulties in recruitment, and 15 were ongoing. One study had identified an important new safety hazard.

CONCLUSIONS

Company postmarketing surveillance studies have made only a limited contribution to the assessment of drug safety, principally because of weak study designs and difficulties in recruitment. The guidelines require modification to take this experience into account.

Influence of dietary intakes of erythorbic acid on plasma vitamin C analyses

D-Erythorbic acid is an epimer of L-ascorbic acid, but lacks antiscorbutic activity. It is commonly used as a food additive, particularly in processed meat items. Except for high-performance liquid chromatography (HPLC) methodology, the commonly used analytical procedures to measure vitamin C do not distinguish between the two isomers. A study with seven adult women demonstrated that the concentration of erythorbic acid present in food items commonly consumed was sufficient to produce interference in plasma vitamin C analyses. With the meals used, 7-23% of the apparent vitamin C in plasma obtained 2 h after the ingestion of the meals was actually erythorbic acid when analyzed by HPLC. To avoid falsely high plasma-serum vitamin C values as a result of erythorbic acid ingestion, the analyses should be conducted on overnight fasting blood specimens or with the use of an HPLC-amperometric method.

Attempts to induce resistance in mice to Schistosoma japonicum and Schistosoma mansoni by exposure to crude schistosome antigens plus cloned glutathione-S-transferases

Several attempts have been made to induce resistance in mice to Schistosoma japonicum (Philippines) or Schistosoma mansoni by exposure to living male and/or female adult worms, their antigens or irradiated cercariae. No resistance was demonstrated in the following cases: re-exposure of mice to cercariae following praziquantel (PZQ) treatment of existing infection; re-exposure of mice following cyclosporin A (CsA) treatment at the time of first cercarial exposure; subcutaneous or intraperitoneal deposition of living male or female worms; repeated intranasal administration of crude worm homogenates plus Bordetella pertussis vaccine (BPV) as adjuvant. Homologous 60Co-irradiated cercariae were very effective at inducing resistance to infection with S. mansoni but not to infection with S. japonicum (Philippines) in a limited series of experiments. A regime of infection, immunization with homologous Escherichia coli-derived glutathione-S-transferases (GST), then PZQ treatment followed by homologous re-exposure did not result in significant resistance in either the S. mansoni or the S. japonicum (Philippines) systems. Mice given irradiated cercariae plus GST were not more resistant to subsequent S. mansoni infection than mice given irradiated cercariae alone. The results generally confirm and extend those reported by others with the conclusion that resistance to schistosomes in mice is difficult to achieve by exposure to adult worm antigens alone. Moreover, additional immunization with the GST available to date as cloned gene products, and injected in Freund's complete adjuvant, does not influence the outcome of exposure to crude worm antigens including any additive effects of protective irradiated cercariae.

Further studies on variable resistance of 129/J and C57BL/6 mice to infection with Schistosoma japonicum and Schistosoma mansoni

Two mouse strains maintained in this laboratory (WEHI) are variably resistant to infection with Schistosoma japonicum and S. mansoni in that worms cannot be found in the liver and portal system in a high proportion (WEHI 129/J mice) or low proportion (C57BL/6 mice) some weeks after exposure to cercariae. Resistance can be as high as 100% in WEHI 129/J mice and is usually around 20% in C57BL/6 mice. The proportion of resistant mice closely parallels the proportion of mice that demonstrate a shunting of microbeads, injected into a mesenteric vein, from liver to lungs. This applies to F1 x WEHI 129/J backcross mice in which the data suggest oligogenic genetic effects although no evidence for a participation of MHC-linked genes in the phenomenon has emerged. 129/J mice derived from the Jackson Laboratory do not show a shunting of beads from the portal system to the lungs but their progeny bred at WEHI do. Germ-free WEHI 129/J mice resemble conventionally-maintained, SPF-derived WEHI 129/J mice in their variable resistance to schistosome infection. No satisfactory explantation for hepato-portal system peculiarities in WEHI 129/J and C57BL/6 mice can be advanced as yet and a possibility raised in this paper is a contribution from nutritional factors such as hypervitaminosis A superimposed on a genetic predisposition in these two related mouse strains.

Studies on the sex ratio of worms in schistosome infections

Sex ratios of adult schistosomes in mice are almost invariably different from 1.0 and are biased towards males. The bias applies to wild rats infected with Schistosoma japonicum and trapped in an endemic area of the Philippines (male:female ratio = 1.7). It also applies to cercariae of snails collected in such areas and assessed by infection of laboratory mice using cercariae from individual snails (male:female ratio may approach 6.0). Experiments were designed to determine if duration of infection in the mammalian host was a factor that influenced the sex ratio of miracidia used for infecting snails and subsequently mice. BALB/c and C57BL/6 mice were infected with 100 cercariae of S. mansoni, and liver eggs harvested at early and late time points for infection of snails and production of cercariae. Two phenomena were demonstrated: firstly, a more pronounced male bias when eggs were harvested late compared with early in infection; secondly, a reduced apparent hatchability of eggs in BALB/c compared with C57BL/6 livers. The possibility is raised by the data that female miracidia within eggs of chronically infected individuals may be more prone to immune damage than male miracidia with important epidemiological consequences.

Cardiovascular, biochemical and hormonal changes during food-induced hypotension in chronic autonomic failure

The cardiovascular, biochemical and hormonal responses to a standard test meal have been investigated in patients with chronic autonomic failure and normal subjects. In autonomic failure there was a rapid (within 15 min), substantial and prolonged fall in blood pressure after the meal. A marked fall in blood pressure also occurred after a liquid meal of similar composition and caloric content, with no change in blood pressure in age-matched subjects with normal autonomic function. In autonomic failure after the test meal the blood pressure reached its nadir (45% fall) after 60 min, and had not returned to pre-meal levels after 3 h. There were no changes in cutaneous and forearm blood flow. In the normal subjects there were no changes in blood pressure after the meal; forearm blood flow fell and cardiac output increased. In autonomic failure there were no changes in plasma noradrenaline levels, unlike the normal subjects. Plasma adrenaline levels were unchanged in both groups. There was a similar rise in levels of plasma renin activity in both groups. The haematocrit and plasma osmolality did not change in either group. Changes in plasma glucose and plasma insulin levels were similar in both groups. The responses of 3 pancreatic gut peptides, neurotensin, pancreatic polypeptide and enteroglucagon, were greater in autonomic failure. Basal levels and responses of vasoactive intestinal polypeptide, cholecystokinin-8 and somatostatin were similar in both groups. The motilin response was greater in normal subjects. We conclude that in patients with autonomic failure there was a rapid, substantial and prolonged fall in blood pressure after a meal. This reduction in blood pressure was not counteracted by an increase in sympathetic nervous activity and other compensatory changes, as occur normally. It was unlikely that osmotic effects of the meal or gut secretions resulted in a significant loss of intravascular fluid into the gut. The fall in blood pressure probably results from vasodilatation within the splanchnic circulation, to which pancreatic and gastrointestinal hormones with vasodilatory actions may contribute.

The significance of stupor in the long-term outcome of chronic schizophrenia

The admission records of 271 long-stay chronic schizophrenic patients, resident in a large psychiatric hospital, were examined in order to identify those who had presented in stupor at the onset of their illness. Twelve patients were found (ten men and two women). When compared, in terms of current mental state and behaviour, with a similar sample of schizophrenics in whom stupor had been absent, significant differences between the two groups were detected, with those presenting in stupor demonstrating a less favourable outcome.

Differential blood pressure and hormonal effects after glucose and xylose ingestion in chronic autonomic failure

1. To investigate whether carbohydrate contributes to postprandial hypotension in autonomic failure, the cardiovascular, biochemical and hormonal effects of oral glucose and an iso-osmotic solution of oral xylose were studied on separate occasions in six patients with chronic autonomic failure. The effects of oral glucose were also studied in eight normal subjects. 2. In the patients oral glucose lowered blood pressure substantially (-34 +/- 7% at 60 min, area under curve -24.9 +/- 3.5%, P less than 0.001) and for a prolonged period (-25 +/- 4% at 120 min). Plasma noradrenaline levels did not change. In the normal subjects blood pressure was unchanged and plasma noradrenaline rose, suggesting a compensatory increase in sympathetic nervous activity. 3. In the patients xylose caused a smaller and more transient fall in blood pressure (-15 +/- 6% at 90 min, area under curve -8.9 +/- 4%, P less than 0.05) with a non-significant elevation in packed cell volume (36.7 +/- 1.8 to 38.2 +/- 1.8). It was therefore unclear if xylose was exerting osmotic effects within the bowel which contributed to the small blood pressure fall. Packed cell volume did not change in either the patients or normal subjects after glucose. 4. In the patients and normal subjects plasma insulin rose after glucose. Insulin levels were unchanged after xylose. Levels of pancreatic polypeptide and neurotensin, a potential vasodilator, rose in the patients only. The latter rose to a similar extent after both glucose and xylose, making it unlikely that neurotensin alone accounted for the hypotension. 5. These studies indicate that the carbohydrate components of a meal, and in particular those causing insulin release, contribute to postprandial hypotension in patients with autonomic failure.