Post-acute phase and sequelae management of epidermal necrolysis: an international, multidisciplinary DELPHI-based consensus

BACKGROUND

Long-term sequelae are frequent and often disabling after epidermal necrolysis (Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)). However, consensus on the modalities of management of these sequelae is lacking.

OBJECTIVES

We conducted an international multicentric DELPHI exercise to establish a multidisciplinary expert consensus to standardize recommendations regarding management of SJS/TEN sequelae.

METHODS

Participants were sent a survey via the online tool "Survey Monkey" consisting of 54 statements organized into 8 topics: general recommendations, professionals involved, skin, oral mucosa and teeth, eyes, genital area, mental health, and allergy workup. Participants evaluated the level of appropriateness of each statement on a scale of 1 (extremely inappropriate) to 9 (extremely appropriate). Results were analyzed according to the RAND/UCLA Appropriateness Method.

RESULTS

Fifty-two healthcare professionals participated. After the first round, a consensus was obtained for 100% of 54 initially proposed statements (disagreement index < 1). Among them, 50 statements were agreed upon as 'appropriate'; four statements were considered 'uncertain', and ultimately finally discarded.

CONCLUSIONS

Our DELPHI-based expert consensus should help guide physicians in conducting a prolonged multidisciplinary follow-up of sequelae in SJS-TEN.

Laser therapy for genital lichen sclerosus: A systematic review of the current evidence base

Background

Lichen sclerosus (LS) is a chronic, inflammatory dermatosis. Initial treatment with superpotent topical corticosteroids is the accepted and evidence-based first-line therapy. For those who do not respond after exclusion of other potentiating factors, the best second-line therapy is unclear. Laser therapy is an emerging treatment for genital LS and despite uncertain efficacy its use is gaining popularity in the private sector.

Objectives

We aimed to review the effectiveness of laser therapy for genital LS in men, women and children.

Methods

We conducted a systematic review of all primary studies reporting the use of laser in genital LS. Ovid MEDLINE, PubMed, Ovid Embase, Cochrane CENTRAL, Web of Science, CINAHL and PsycINFO were searched from inception to February 2021. The quality of the studies was assessed using the revised Cochrane risk-of-bias tool for randomized trials, ROBINS-I tool for non-randomized trials and Joanna Briggs Institute checklist for case studies.

Results

A total of 24 studies, involving 616 adults, met inclusion criteria. These were six randomized controlled trials (RCTs), one non-randomized trial, nine single arm trials and eight case series. Where assessed, most studies suggest that laser therapy in patients with LS may improve symptoms, clinical signs, quality of life and sexual function. However, results were highly heterogeneous and methodological quality was very low, therefore meta-analysis was not possible.

Conclusions

There is poor evidence to support the use of laser therapy for genital LS at present. Effectiveness of laser needs to be robustly investigated in well-conducted RCTs.

647 Management of Malignant Upper Urinary Tract Obstruction

Background

Malignant Upper Urinary Tract Obstruction (MUUTO) is a common emergency presentation. These are often complex patients and require multiple specialty input to make time-critical decisions. There are currently no national guidelines for the management of MUUTO, a review was conducted to assess the management and outcomes of MUUTO.

Aim

To agreed and review a pathway for patients with MUUTO in order to streamline patient care and to review the management.

Method

The pathway was devised by several consultants at Oxford University Hospital. Through retrospective data collection, the outcomes over six months were reviewed.

Results

Over the six-month period 49 interventions were performed for MUUTO; 44 Percutaneous Nephrostomy (PCN) and five cystoscopies with retrograde ureteric stents (RUS). Patients were admitted to urology in 45% of cases and oncology in 39%. The obstruction was located above the pelvis in 16 (33%) of the cases and within the pelvis in 25 (51%). The most common cancers causing obstruction were bladder cancer (41%), prostate (16%), and colorectal (14%). MDT advice was sought in 63% of cases. The mean time from diagnosis to the intervention was four days. Of the five retrograde inserted ureteric stents, four were unsuccessful and the patients proceeded to PCN. At the conclusion of data collection, 26 (53%) patients had died.

Discussion

The most striking findings were the high failure rate of RUS and the overall poor prognosis of MUUTO. As such this review suggests that more patients should proceed directly to PCN for decompression.

Suitability of testicular tissue fluid from castrated piglets to verify sow -vaccination status and herd monitoring

INTRODUCTION

In a proof of concept, PCV2-specific IgG-antibodies from testicular tissue fluid of seven-day-old castrated piglets were measured to verify the vaccination status of their mothers. Twelve randomly selected sows were vaccinated twice during the last third of gestation with a PCV2 vaccine, while ten controls received only adjuvant. PCV2- specific IgG-antibody titers of serum and colostrum from the sows were correlated with PCV2-specific IgG-antibody titers of serum and testicular tissue fluid of their castrated male offspring. Vaccinated sows showed significantly higher average PCV2-specific IgG-antibody titers in serum (29250 ELISA units, EU) and colostrum (65410 EU) compared to 980 EU and 2630 EU of the control group, respectively. Moreover, significantly higher average concentrations of antibodies were also measured in the serum (9362 EU vs. 247 EU) and the testicular tissue fluid (4022 EU vs. 354 EU) of piglets from vaccinated compared to piglets from adjuvant administered sows. Importantly, a strong linear correlation between PCV2-specific IgG-antibodies in the serum of the piglets and in their testicular tissue fluid was found (rs = 0.9148). PCV2-specific IgG-antibody titers of testicular tissue fluid from five randomly selected piglets allowed the determination of the vaccination status of the herd with a reliability of 98% for vaccinated and 73% for unvaccinated sows. Furthermore, using castration waste products is a very animal friendly method to replace painful and time-consuming blood samplings for herd monitoring or to verify vaccination status.

Vulval acne: a case series describing clinical features and management

Intermittent inflammation of the vulval pilosebaceous units is common and usually self-limiting, but some patients experience recurrent and more troublesome symptoms. There is a scarcity of information on this problem. We describe the clinical and histological features in these patients and the response to treatment. A retrospective, observational study of 16 patients with this phenomenon of recurrent, protracted folliculocentric inflammation of the vulval pilosebaceous unit was performed. Details on the clinical features, histology and response to treatment were collected. Mean age at presentation was 32 years (range 21-45). All patients reported recurrent painful papules and pustules on the labia majora and labia minora. Nine patients reported a cyclical pattern to the development of lesions, with premenstrual exacerbation being most common. Histological examination of these lesions showed a folliculocentric microabscess formation surrounded by an acute and chronic inflammatory cell infiltrate, with a focal foreign-body granulomatous reaction. All our patients responded well to tetracycline, antiandrogenic or retinoid therapy. We propose the term 'vulval acne' for this condition and propose a stepwise approach to its management. We hope to highlight this as a common but underreported entity.

2419Reparative macrophage transplantation for myocardial repair: a refinement of bone marrow mononuclear cell-based therapy

Background

Recent research has revealed that reparative (alternatively activated or M2-like) macrophages play an important role in post-myocardial infarction (MI) cardiac repair, proposing that augmentation of these cells will enhance recovery from MI. Transplantation of bone marrow mononuclear cells (BM-MNCs) is an emerging therapy for MI while its therapeutic efficacy in previous clinical trials is not satisfactory. Given that BM-MNCs are a natural source of macrophages, we hypothesized that induced differentiation/polarisation of BM-MNCs to reparative macrophages before transplantation may enhance the effect of BM-MNC transplantation.

Purpose

This study aimed to develop a robust in vitro protocol to produce reparative macrophages from BM-MNCs and to establish the pre-clinical proof of concept data for reparative macrophage transplantation for the treatment of MI.

Methods and results

Mouse BM-MNCs were treated with M-CSF plus IL-4, IL-10, TGF-β1 or combinations of these in vitro. The concomitant M-CSF+IL-4 protocol (both 20ng/ml) produced the highest rate (89.7±0.7%) and number (1.7-fold larger than the original cell number) of CD11b+F4/80+CD206+ macrophages. Expression and secretion of tissue repair-related factors of the produced cells, including IGF-1, TGF-β1, VEGF and IL1-ra, were more extensive compared to BM-MNCs. Then, 5x105 BM-MNC-derived reparative macrophages, 5x105 BM-MNCs, or saline only (control) were intramyocardially injected in a mouse MI model based on coronary artery ligation. At 4 weeks after treatment, echocardiography demonstrated that reparative macrophage transplantation markedly improved cardiac function (left ventricular ejection fraction; 57.2±1.6%, n=11) compared to both BM-MNC transplantation (48.4±1.3%, n=9) and control group (44.4±2.0%, n=9). Histological studies showed that infarct size was the smallest after reparative macrophage transplantation in association with the greatest tissue repair in the peri-infarct myocardium, including augmented microvascular formation, reduced cardiomyocyte hypertrophy and reduced pathological interstitial fibrosis. These were corresponded to amplified myocardial upregulation of tissue repair-related genes. Of note, survival of donor reparative macrophages in the heart post-transplantation was >10-fold greater compared to BM-MNCs. It was also found that reparative macrophage transplantation increased host-derived cardiac reparative macrophages. This might be a part of the mechanism by which reparative macrophage transplantation augmented myocardial repair, and our in vitro antibody neutralisation study indicated that TGF-β1 played a role in this donor macrophage-to-host macrophage pathway.

Conclusion

M-CSF+IL-4 treatment was effective in producing reparative macrophages from BM-MNCs in vitro. Addition of this pre-treatment improved the therapeutic effect of BM-MNC transplantation. Further pre-clinical and clinical development of this advanced cell therapy is warrantied.

Acknowledgement/Funding

British Heart Foundation (RG/15/3/31236); Heart Research UK (RG2618/12/13 and TRP06/15); St Barts Medical School London

Factors influencing the rate of incidents in a United Kingdom high secure psychiatric hospital: Weekend, ward round and diagnostic effect?

Introduction

Broadmoor is a high secure psychiatric hospital divided into personality disorder (PD) and mental illness (MI) pathways. Whenever an incident occurs, it should be recorded. To better understand which factors influence the rate of incidents, such as diagnosis or intervention by medical and psychological staff, we examined the difference in the number of incidents recorded on weekdays versus weekends, ward round (WR) versus non-WR days and the PD versus MI pathways.

Method

All incidents recorded over a one-year period (3.11.2014–2.11.2015) were examined. Extraneous incidents were excluded, leaving subgroups of “aggressive” (physical and verbal) and “physical” (excluding verbal) incidents which were analysed. Data were adjusted for the difference in number of beds in each pathway.

Results

Of the 2369 incident reports included, more were recorded per day on weekdays than weekends, with little difference on WR versus non-WR days. The rates of both types of incidents were similar on both PD and MI admission wards, although the rate of “physical” incidents was 2.6 times higher and “aggressive” incidents 3.3 times higher in PD compared to MI rehabilitation wards.

Conclusion

The findings suggest the presence of medical and psychological staff during the week, and possibly the requirements they place on patients, may increase the rate of incidents within the hospital. Despite comparable rates on admission, MI rehabilitation wards have far fewer incidents than PD rehab wards, which may reflect the more intractable nature of PD versus MI. More work is required to confirm these findings.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Vulval Crohn's disease – a multi-specialty approach

We report a case of Crohn's disease where the patient initially presented with vulval ulceration to the gynaecology unit. Initial investigations were planned jointly by both the gynaecology and genitourinary medicine staff. An examination under general anaesthetic by both teams was performed and biopsies taken. These showed a chronic inflammatory process with epithelioid granulomas. The teams then referred the case to the dermatology team who made the diagnosis of vulval Crohn's disease and initiated treatment with prednisolone and azathioprine. The case illustrates the need for a multi-speciality approach when dealing with such cases.

Cattle movement as a risk factor for epidemics

Cattle movement is one of the most important risk factors for the occurrence of an epidemic. It is a legal requirement in Switzerland that every cattle movement be reported, and this information is held in the Swiss cattle movement database (Tierverkehrsdatenbank, TVD). Using this data we examined all movements, focusing on the geographical distribution of these movements in relation to the spread of epizootic diseases. We considered the period 01 January 2011 through 30 January 2012, in which a total of 786'462 cattle were moved. Looking at premises individually, a maximum of 901 possible transfers of an infectious agent were found on a specific day after the arrival of another cattle. Furthermore, we found that there were more cattle movements in summer than in winter, due to movements of cattle to and from alpine pastures. There were also prominent regional differences. On the first day after the arrival of a cattle there was a minimum of zero and a maximum of 99'168 possible transfers of an infectious agent. Nevertheless, in most cases there were no cattle moved on the first day following the arrival of a cattle (91.4%). In terms of our epizootics of interest, the following numbers of cattle were moved within the relevant incubation periods: 19'779'551 possible transfers for the Lumpy skin disease, with an incubation period of 28 days; 9'891'665 or 15'025'741 possible transfers for foot and mouth disease, depending on the incubation period of 14 or 21 days; 15'025'741 possible transfers for cattle plague and vesicular stomatitis, both with an incubation period of 21 days. The presented data show a large cattle traffic in Switzerland, and therefore suggest that it is very seldom that an infectious agent is able to start an epidemic.

Usual vulval intraepithelial neoplasia in HIV-positive women - a case series

Usual or undifferentiated type vulval intraepithelial neoplasia (VIN) is more common in young women and is usually associated with high-risk human papillomavirus infection. It is associated with the development of basaloid or warty squamous cell carcinoma. Studies have shown that HIV-positive women have an increased risk of VIN and invasive vulval carcinoma, but there is a paucity of data about this cohort of women. The objective of this study was to describe the clinical features and treatment responses of HIV-positive women diagnosed with VIN in a specialist vulval dermatology clinic. HIV-positive women diagnosed with VIN from 2007 to 2013 were retrospectively identified. Data were collected on demographics, clinical features, treatments and outcomes. Seven cases were retrospectively identified. The median CD4 cell count at presentation was 500 cells/mm³ (range 59-761). Five had multifocal VIN. Five were treated with imiquimod alone, one had surgical excision and one patient was treated with imiquimod and surgery. Five of the seven had complete resolution of disease. HIV-positive patients with VIN had good responses to treatment with imiquimod. They were likely to be stable on combination antiretroviral therapy at presentation, have multifocal disease and concurrent vaginal, anal or cervical intraepithelial neoplasia.

Influence of feeding and UVB exposition on the absorption mechanisms of calcium in the gastrointestinal tract of veiled chameleons (Chamaeleo calyptratus)

The purpose of this study was to investigate the influence of feeding and UVB exposition on the occurrence and distribution patterns of vitamin D receptors (VDR) and calbindin D28k (Cb-D28k) in the gastrointestinal tract of veiled chameleons. Thus, 56 veiled chameleon hatchlings were divided into six treatment groups: UV (with UVB exposure); No (no supplements, no UVB exposure); CaAUV (with calcium (Ca), vitamin A supplementation, UVB exposure); CaA (with Ca, vitamin A supplementation); CaADUV (with Ca, vitamin A, vitamin D supplementation, UVB exposure); and CaAD (with Ca, vitamin A, vitamin D supplementation). Animals were reared under the suspected conditions for 6 months on locust-based diets. Tissue samples of stomach, duodenum, ileum and colon were taken, and semi-quantitative immunohistochemical methods (IHC) were performed to detect Cb-D28k and VDR. VDR immunoreactions were higher in the luminal epithelium of the duodenum than in that of the ileum. VDR immunoreactions in the luminal epithelium were higher at the base of the villi of the duodenum as compared to the tip. Cb-D28k immunoreactions were mainly observed in the luminal epithelium of the duodenum. The two groups treated with all dietary supplements (CaADUV, CaAD) exhibited a higher Cb-D28k immunoreaction as those with no supplements and UVB exposure only. No immunoreaction for both proteins could be detected in the stomach. This study suggests that the duodenum plays an important role in the active transcellular absorption of Ca in veiled chameleons as shown by the immunohistochemical detection of VDR and Cb-D28k. Expression of Cb-D28k, in particular, appears to be regulated by dietary supplementation of vitamin D and vitamin A. VDRs, however, tended to be upregulated when animals were not supplemented with Ca, vitamin D and vitamin A. This may be due to the decreased Ca concentrations which caused vitamin D activation in the skin without any supplementation, but UVB exposure.

Multi-test analysis and model-based estimation of the prevalence of Taenia saginata cysticercus infection in naturally infected dairy cows in the absence of a 'gold standard' reference test

The diagnostic values of seven serological tests (ELISAs) and of the obligatory European Union-approved routine visual meat inspection for the detection of Taenia saginata cysticercosis were investigated. A total of 793 slaughtered dairy cows were selected in three European Union approved abattoirs in Switzerland, an endemic area (apparent prevalence by enhanced meat inspection up to 4.5%) with typically low parasite burdens. ELISAs based on a somatic larval antigen, isoelectric focused somatic larval antigen, larval excretory/secretory antigens, peptide HP6-2, peptide Ts45S-10, pooled peptide solution and a monoclonal antibody antigen capture assay were initially screened. As there is no perfect diagnostic 'gold standard' reference test, the obligatory meat inspection and four selected serological tests were further analysed using Bayesian inference to estimate the "true" prevalence and the diagnostic test sensitivities and specificities. The ELISA for specific antibody detection based on excretory/secretory antigens showed highest sensitivity and specificity with 81.6% (95% credible interval: 70-92) and 96.3% (95% credible interval: 94-99), respectively. The Bayesian model estimated the specificity of the ELISA, based on the synthetic peptide Ts45S-10 as 55.2% (95% credible interval: 46-65) and sensitivity as 84.7% (95% credible interval: 82-88). The sensitivity of the ELISA based on mAbs, detecting circulating antigen, was 14.3% (95% credible interval: 9-23) with a specificity of 93.7% (95% credible interval: 92-96). The diagnostic sensitivity of the obligatory standard European Union meat inspection procedure for the detection of T. saginata cysticercus infection at the abattoir was estimated to be 15.6% (95% credible interval: 10-23). Based on these data, the modelled prevalence of cysticercosis in dairy cows presented at abattoirs in Switzerland was estimated to be 16.5% (95% credible interval: 13-21). These cattle also had a high prevalence of infection with Dicrocoelium dendriticum (60.8%) and Fasciola hepatica (13.5%).

The association between trunk muscle endurance and lumbo-pelvic stability in adolescent low back pain: A cross sectional study

Decreased trunk muscle endurance has been identified as a risk factor for adolescent LBP, and poor lumbo-pelvic stability has been found to be associated with LBP in the adult population. The aim of the study was to investigate the association between adolescent LBP, trunk muscle endurance and poor lumbo-pelvic stability. Design: A cross sectional study. Participants: 80 adolescents in grade 8 to grade 11, aged 12 to 17 years, at three high schools in Gauteng, who agreed to participate in the study. Method: Data was collected by means of a validated questionnaire and physical tests. The active straight leg raise test was used to record the lumbo-pelvic stabilising muscles. The Sorensen, Shirado and side-bridge tests were used to record trunk extensor, flexor and side flexor muscle endurance, respectively. Results: The results revealed a lifetime prevalence of LBP of 82.50%, one year prevalence of 78.80% and point prevalence of 23.80%. Adolescents with LBP demonstrated decreased trunk extensor muscle endurance but increased trunk flexor muscle endurance (p=0.044), compared to non-LBP adolescents. Poor lumbo-pelvic stability was not associated with adolescent LBP, but was associated with decreased extensor trunk muscle endurance (p=0.031). Conclusion: There was an association between trunk flexor muscle endurance and adolescent LBP, and between decreased trunk extensor muscle endurance and poor lumbo-pelvic stability. No association was found between LBP and poor lumbo-pelvic stability.

The effectiveness of physiotherapy in cervicogenic headache and concurring temporomandibular dysfunction: a case report

The aim of this case report is to describe the use of physio-therapy interventions in a patient diagnosed with cervicogenic headache(CGH) and temporomandibular dysfunction (TMD). This case study involveda 26 year old male. The subject’s cervical and temporomandibular joint(TMJ) active range of movement; passive accessory movements; headacheintensity, periodicity and response to analgesics; TMJ clicking and discomfort;Numerical Pain Rating Scale (NPRS) scores, were assessed on initial assessment and on discharge 14 weeks later. The physiotherapy interventionincluded cervical and TMJ mobilisation (Maitland approach); trigger pointtherapy and massage; strengthening of the deep cervical neck flexors and scapulothoracic muscles; and posture correction. The subject improved on all outcome measures and was discharged after nine physiotherapy sessions, withfull cervical and TMJ range of movement, improved muscle strength and decreased headache intensity and frequency.This case describes a positive outcome for a patient diagnosed with cervical headaches and temporomandibular dysfunction in which physiotherapy interventions aimed at correcting joint dysfunction, myofascial pain and decreased muscle strength were used effectively.

Testing for HER2 in breast cancer

HER2 is a paradigm of a molecular target whose appropriate assessment is pivotal in the targeting of novel therapies for breast cancer, notably including Herceptin/Trastuzumab. Determining the correct levels requires immunohistochemical and molecular biological skills that are reproducible and measurable, coupled with a knowledge of the appropriate morphological and pathobiological context. Attaining these goals is not easy and laboratories testing for HER2 should maintain a high level of throughput of tests and engage in a recognized external quality assurance scheme. Fluorescence in-situ hybridization testing remains a particular challenge and there is a range of testing strategies. This testing forms the model for the identification of other novel molecular targets. In the future rapid throughput techniques such as real-time quantitative polymerase chain reaction (rqPCR), tissue microarrays or both should bring significant economies of cost and scale.

Trial of heparin in viper bites

AIMS OF THE STUDY

Viper bites produce hematotoxicity and coagulopathy which may be either true disseminated intravascular coagulation (DIC) or DIC-like syndrome. Role of heparin is studied in the present study of viper bite cases as use of heparin provides a rational therapy for defibrination caused by viper envenomation.

METHODOLOGY

One hundred and twenty two patients with viper bite and incoagulable blood were randomised into test group and control group. Test group received heparin in addition to antisnake venom (ASV). Efficacy was assessed by monitoring bleeding time (BT), clotting time (CT), prothrombin time (PT), platelets, fibrinogen, blood urea (BU), serum creatinine, development of complications and overall outcome.

RESULTS

Heparin group showed favourable outcome in all parameters studied. But many of them were not statistically significant.

CONCLUSION

Heparin seems to be having a beneficial role which needs to be confirmed by larger trials and longer duration of heparin administration.

The distribution of Biomphalaria spp. in different habitats in relation to physical, biological, water contact and cognitive factors in a rural area in Minas Gerais, Brazil

A total of 256 sites in 11 habitats were surveyed for Biomphalaria in Melquiades rural area (State of Minas Gerais) in August and November 1999 and in March 2000. Of the 1,780 Biomphalaria collected, 1,721 (96.7%) were B. glabrata and 59 (3.3%) B. straminea. Snails were found in all habitats except in wells, with the largest mean numbers in tanks, seepage ponds and canals, and the smallest numbers in springs, rice fields and fishponds. People's knowledge of the occurrence of Biomphalaria at the collection sites and the presence of Biomphalaria ova were strongly correlated with the occurrence of snails, and distance between houses and collection sites, as well as water velocity were inversely correlated with Biomphalaria occurrence (p < 0.001). The strongest predictor o f Biomphalaria occurrence was the presence of tilapia fish in fishponds. Fourteen Biomphalaria (0.8% of all snails) found at 6 sites were infected with Schistosoma mansoni. Suggestions are made for the utilization of local people's knowledge in snail surveys and further studies are recommended on the possible use of tilapia for biological control of Biomphalaria in fishponds, as well as modeling of S. mansoni transmission and reinfection.

Unlocking the archive--gene expression in paraffin-embedded tissue

The histopathology archive represents a vast, well-characterized source of specimens covering virtually every disease and is available for molecular biological investigation. The archive has in recent years become widely used for molecular genetic analysis and DNA can be routinely extracted from formalin-fixed, paraffin-embedded tissue. More recently, archival specimens have become a source of material for extensive analysis of mRNA expression utilizing DNA microarrays, real-time quantitative reverse transcriptase polymerase chain reaction (PCR), and in situ hybridization and amplification techniques. These techniques will enable a greater understanding of the changes that occur in gene function during every stage of the development of disease and will lead to better diagnosis, better evaluation of prognosis, and better treatment through targeted therapeutic regimes.

A mathematical treatment of AIDS and condom use

In this paper we examine the impact of condom use on the sexual transmission of human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) amongst a homogeneously mixing male homosexual population. We first derive a multi-group SIR-type model of HIV/AIDS transmission where the homosexual population is split into subgroups according to frequency of condom use. Both susceptible and infected individuals can transfer between the different groups. We then discuss in detail an important special case of this model which includes two risk groups and perform an equilibrium and stability analysis for this special case. Our analysis shows that this model can exhibit unusual behaviour. As normal, if the basic reproduction number, R0, is greater than unity then there is a unique disease-free equilibrium which is locally unstable and a unique endemic equilibrium. However, when R0 is less than unity two endemic equilibrium solutions can also co-exist simultaneously with the disease-free solution which is locally stable. Numerical simulations using realistic parameter values confirm this and we find that in certain circumstances the disease-free solution and one of the endemic solutions are both locally asymptotically stable, while the other endemic solution is unstable. This unusual behaviour has important implications for control of the disease as reducing R0 to less than unity no longer guarantees eradication of the disease. For a restricted special case of this two-group model we show that there is only the disease-free equilibrium for R0 < or = 1 which is globally stable. For R0 > 1 the disease-free equilibrium is unstable and there is a unique endemic equilibrium which is locally stable. We then attempt to fit the model to HIV and AIDS incidence data from San Francisco, USA. The paper concludes with a brief discussion.

Schistosomiasis

The trematode parasites in the family Schistosomatidae (phylum Platyhelminthes) infect a wide range of vertebrates. Three species of the genus Schistosoma are of major medical importance. This unit deals exclusively with the parasite Schistosoma mansoni, which is the species most frequently maintained in the laboratory. Among the far-ranging investigations in the immunology of schistosomiasis are studies in vaccine development, immunopathology of granulomatous inflammation and fibrosis, eosinophil function, and in vivo regulation of T(H)1 and T(H)2 responses. This unit describes maintenance and collection procedures for various stages of the schistosome that have immunologic interest, including infection of mice with cercariae, collection of cercariae, preparation of in vitro-derived schistosomules and in vivo-derived schistosomules, and collection of adult worms and eggs. Included also are techniques for preparing soluble egg antigen (SEA), one of the more commonly used schistosome antigenic preparations. A discussion is given of the basic steps that are important in maintaining the snail intermediate host, and infecting the snails with schistosome miracidia. The unit deals exclusively with the parasite Schistosoma mansoni, which is the species most frequently maintained in the laboratory. Since part of the life cycle of all schistosomes involves a snail host, a description of proper maintenance for the snails is provided. Often, problems in experiments can be traced back to improper snail and parasite maintenance, or lack of attention to detail during mammalian exposure to the infective stage (cercaria) of the parasite.

Three stage AIDS incubation period: a worst case scenario using addict-needle interaction assumptions

In this paper we develop and analyse a model for the spread of HIV/AIDS amongst a population of injecting drug users. We start off with a brief literature survey and review; this is followed by the derivation of a model which allows addicts to progress through three distinct stages of variable infectivity prior to the onset of full blown AIDS and where the class of infectious needles is split into three according to the different levels of infectivity in addicts. Given the structure of this model we are required to make assumptions regarding the interaction of addicts and needles of different infectivity levels. We deliberately choose these assumptions so that our model serves as an upper bound for the prevalence of HIV under the assumption of a three stage AIDS incubation period. We then perform an equilibrium and stability analysis on this model. We find that there is a critical threshold parameter R(0) which determines the behaviour of the model. If R(0)< or =1, then irrespective of the initial conditions of the system HIV will die out in all addicts and all needles. If R(0)>1, then there is a unique endemic equilibrium which is locally stable if, as is realistic, the time scale on which addicts inject is much shorter than that of the other epidemiological and demographic processes. Simulations indicate that if R(0)>1, then provided that disease is initially present in at least one addict or needle it will tend to the endemic equilibrium. In addition we derive conditions which guarantee this. We also find that under calibration the long term prevalence of disease in our variable infectivity model is always greater than in an equivalent constant infectivity model. These results are confirmed and explored further by simulation. We conclude with a short discussion.

Three-stage AIDS incubation period: a best case scenario using addict-needle interaction assumptions

In this paper we extend the 'needles that kill' model discussed in Kaplan & O'Keefe (1993) to allow addicts to progress through three-stages of variable infectivity prior to the onset of full-blown AIDS, and where the class of infectious needles is split into three according to the different levels of infectivity in addicts. Given the structure of this model we are required to make assumptions regarding the interaction of addicts and needles of different infectivity levels. We deliberately choose these assumptions so that our model serves as a lower bound for the prevalence of HIV under the assumption of a three-stage AIDS incubation period. We find that there is a critical threshold parameter R0 which determines the behaviour of the model. If R0 > 1 then there is a unique endemic equilibrium which is locally stable if, as is realistic, the timescale on which addicts inject is much shorter than that of the other epidemiological and demographic processes. Simulations indicate that if R0 > 1, then provided that disease is initially present in at least one addict or needle then it will tend to the endemic equilibrium. In addition, we derive conditions which guarantee this. We also find that under calibration the long-term prevalence of disease in the 'needles that kill' model is the same as in our three-stage model.

Schistosoma mansoni: use of a subtractive cloning strategy to search for RFLPs in parasite-resistant Biomphalaria glabrata

A subtractive cloning strategy has been applied for the identification of two cDNA clones whose corresponding transcripts were elevated in Schistosoma mansoni-resistant (BS-90) compared to susceptible (M-line) snails. Clone pBS11 encoded a 1.9-kb transcript that was more elevated compared to a 500-bp transcript encoded by clone pBS12. Consequently, more attention was focused on the molecular characterization of clone pBS11. Results showed that the transcript encoded by this clone was expressed in the albumen gland and was developmentally regulated. Sequence analysis of pBS11 demonstrated the presence of an open reading frame that corresponded to a novel Biomphalaria glabrata albumen gland gene product. Comparative Southern analysis of the resistant and susceptible snail lines using pBS11 as probe indicated the presence of a BamHI and EcoRI RFLP between the two strains.

Serum and gastric luminal epidermal growth factor in Helicobacter pylori-associated gastritis and peptic ulcer disease

BACKGROUND

Helicobacter pylori is the cause of chronic (type B) gastritis, duodenal ulceration (DU), and gastric ulceration (GU). Smoking is associated with delayed ulcer healing. Epidermal growth factor (EGF) is produced in the salivary and Brunner's glands of the upper gastrointestinal tract, inhibits gastric acid secretion, and is a powerful mitogen.

MATERIALS AND METHODS

We sought to determine gastric luminal EGF (GL-EGF) in smokers and patients with Hp-associated DU and the effects of Hp eradication. Our aim was to determine GL-EGF in patients with GU and the effect of ulcer healing and to measure serum EGF in patients with Hp gastritis with or without DU disease.

RESULTS

GL-EGF was reduced in smokers compared to controls (p = .008). Subjects with HP gastritis had reduced GL-EGF compared to controls (p = .0002). There was no difference in GL-EGF between Hp-positive subjects who had DU and those with chronic gastritis alone. Eradication of Hp from those patients with DU had no effect on the low levels of GL-EGF. There was no difference between GL-EGF in Hp gastritis alone and in Hp-associated active GU. GL-EGF fell after ulcer healing (p = .04), a difference confirmed by analysis of paired samples from patients before and after ulcer healing (p = .03). There was no difference in serum EGF between controls and subjects with Hp infection. There was no difference in serum EGF in subjects with DU associated and non-ulcer-associated gastritis.

CONCLUSIONS

Subjects with Hp gastritis, or those who smoke, had low concentrations of GL-EGF regardless of whether DU was present. Eradication of Hp did not return the concentrations of GL-EGF to normal in DU subjects. Individuals and Hp gastritis and inactive GU had low levels of GL-EGF compared to non-ulcer Hp infection. The relative increase in GL-EGF that occurred with ulceration of the gastric mucosa may have resulted from the development of an ulcer-associated cell lineage. Serum EGF did not play a role in the pathogenesis of Hp gastritis or of associated DU ulcer disease.

Fluorescent polymerase chain reaction of a panel of CA repeats on chromosome 6 in the indolent phase of follicular centre cell lymphoma

Twenty-four cases of histologically defined follicle centre cell (FCC) lymphoma have been examined for allele imbalance at 19 microsatellite loci spanning the length of chromosome 6, including six markers within the major histocompatibility complex (MHC), using fluorescent polymerase chain reaction (PCR) to amplify microsatellites. Nineteen cases were observed in which imbalance of one or more markers on chromosome 6 had occurred (79%). The frequency of allele imbalance was significantly higher on 6p than 6q, and two regions of deletions, 6p24-25 and 6p21.3-23, were identified in which the loci showed a significantly high allele imbalance frequency.

Antenatal screening for cystic fibrosis

OBJECTIVE

To assess the practicality of implementing antenatal screening for cystic fibrosis in Yorkshire.

DESIGN

Prospective study in which all pregnant women were offered testing for the delta F508 mutation which accounts for about 85% of carriers in Yorkshire. The reproductive partners of those found to be cystic fibrosis carriers were then tested and any carrier referred for genetic counselling.

SETTING

Antenatal clinics in two hospitals and eight general practices.

POPULATION

Six thousand and seventy-one pregnant women.

RESULTS

A total of 3773 women (62%) accepted the screening offer. This was a lower uptake rate than in other published UK studies: Aberdeen (85-91%), Manchester (85%), Edinburgh (76-84%) and Oxford (67%). Nonetheless there were large and statistically significant differences in the uptake rate between centres within the study: 78% and 60% for the two hospitals and 67% for the general practices. One hundred and thirty women (3.4%) were found to be carriers and three carrier couples were identified. The median time interval for the laboratory to produce a result was five days and the cost was pounds 16 on average.

CONCLUSIONS

Antenatal screening for cystic fibrosis does not pose any special practical difficulties. It would be feasible to introduce it into routine practice in Yorkshire.

Promoter region polymorphism in the human TNF-alpha gene is not associated with lichen sclerosus

The pathogenesis of lichen sclerosus remains unknown. However, it has been frequently associated clinically with autoimmunity. The MHC haplotype A1, B8, DR3 is associated with many autoimmune conditions and has also been associated with the uncommon allele of the tumour necrosis factor (TNF-alpha) promoter polymorphism. This allele is also associated with higher production of TNF in vivo and in vitro, and thus it has been speculated that it is the TNF-alpha gene which underlies the genetic association of many diseases with the autoimmune haplotype. There have been many reports of HLA associations with lichen scleroses, but these have not been concordant. We therefore decided to analyse the TNF-alpha polymorphism in patients with lichen scleroses to determine if TNF-alpha was likely to play a role in susceptibility or severity of lichen scleroses. No association between alleles of the TNF-alpha polymorphism and lichen scleroses was found.

Allele imbalance at tumour suppressor loci during the indolent phase of follicle centre cell lymphoma

We have examined 41 cases of follicle centre cell lymphoma with fluorescent PCR of microsatellite repeats closely linked to or within six tumour suppressor gene loci (APC, DCC, P53, RB1, WT1 and NM23). These probes are highly informative with heterozygousity rates in the range of 57%-90%. In addition we have used four loci from chromosome 6 (D6S260, TNFa, D6S281 and D6S262) as control loci which are unlikely to be involved in the pathogenesis of lymphoma. Of 369 informative PCR reactions allele imbalance was identified in 38 (10%) and this was seen in 23 of the 41 cases. Looking at individual loci allele imbalance was seen in APC(1) 11%, APC(2) 12%, P53(1) 5%, P53 (2) 7%, WT1 5%, RB1 13%, DCC 18% and NM23 0%. This frequency of change was no different from that seen at the control loci D6S260 16%, TNFa 20%, D6S281 4% and D6S262 9%. In the indolent phase of germinal centre cell lymphoma there is therefore quite a high rate of allele imbalance at all loci but this is no higher in those loci linked to tumour suppressor genes.