In vivo targeted DamID identifies CHD8 genomic targets in fetal mouse brain

Genetic studies of autism have revealed causal roles for chromatin remodeling gene mutations. Chromodomain helicase DNA binding protein 8 (CHD8) encodes a chromatin remodeler with significant de novo mutation rates in sporadic autism. However, relationships between CHD8 genomic function and autism-relevant biology remain poorly elucidated. Published studies utilizing ChIP-seq to map CHD8 protein-DNA interactions have high variability, consistent with technical challenges and limitations associated with this method. Thus, complementary approaches are needed to establish CHD8 genomic targets and regulatory functions in developing brain. We used in utero CHD8 Targeted DamID followed by sequencing (TaDa-seq) to characterize CHD8 binding in embryonic mouse cortex. CHD8 TaDa-seq reproduced interaction patterns observed from ChIP-seq and further highlighted CHD8 distal interactions associated with neuronal loci. This study establishes TaDa-seq as a useful alternative for mapping protein-DNA interactions in vivo and provides insights into the regulatory targets of CHD8 and autism-relevant pathophysiology associated with CHD8 mutations.

Deletion of a non-canonical regulatory sequence causes loss of Scn1a expression and epileptic phenotypes in mice

BACKGROUND

Genes with multiple co-active promoters appear common in brain, yet little is known about functional requirements for these potentially redundant genomic regulatory elements. SCN1A, which encodes the NaV1.1 sodium channel alpha subunit, is one such gene with two co-active promoters. Mutations in SCN1A are associated with epilepsy, including Dravet syndrome (DS). The majority of DS patients harbor coding mutations causing SCN1A haploinsufficiency; however, putative causal non-coding promoter mutations have been identified.

METHODS

To determine the functional role of one of these potentially redundant Scn1a promoters, we focused on the non-coding Scn1a 1b regulatory region, previously described as a non-canonical alternative transcriptional start site. We generated a transgenic mouse line with deletion of the extended evolutionarily conserved 1b non-coding interval and characterized changes in gene and protein expression, and assessed seizure activity and alterations in behavior.

RESULTS

Mice harboring a deletion of the 1b non-coding interval exhibited surprisingly severe reductions of Scn1a and NaV1.1 expression throughout the brain. This was accompanied by electroencephalographic and thermal-evoked seizures, and behavioral deficits.

CONCLUSIONS

This work contributes to functional dissection of the regulatory wiring of a major epilepsy risk gene, SCN1A. We identified the 1b region as a critical disease-relevant regulatory element and provide evidence that non-canonical and seemingly redundant promoters can have essential function.

Neuroanatomy and behavior in mice with a haploinsufficiency of AT-rich interactive domain 1B (ARID1B) throughout development

BACKGROUND

One of the causal mechanisms underlying neurodevelopmental disorders (NDDs) is chromatin modification and the genes that regulate chromatin. AT-rich interactive domain 1B (ARID1B), a chromatin modifier, has been linked to autism spectrum disorder and to affect rare and inherited genetic variation in a broad set of NDDs.

METHODS

A novel preclinical mouse model of Arid1b deficiency was created and validated to characterize and define neuroanatomical, behavioral and transcriptional phenotypes. Neuroanatomy was assessed ex vivo in adult animals and in vivo longitudinally from birth to adulthood. Behavioral testing was also performed throughout development and tested all aspects of motor, learning, sociability, repetitive behaviors, seizure susceptibility, and general milestones delays.

RESULTS

We validated decreased Arid1b mRNA and protein in Arid1b+/- mice, with signatures of increased axonal and synaptic gene expression, decreased transcriptional regulator and RNA processing expression in adult Arid1b+/- cerebellum. During neonatal development, Arid1b+/- mice exhibited robust impairments in ultrasonic vocalizations (USVs) and metrics of developmental growth. In addition, a striking sex effect was observed neuroanatomically throughout development. Behaviorally, as adults, Arid1b+/- mice showed low motor skills in open field exploration and normal three-chambered approach. Arid1b+/- mice had learning and memory deficits in novel object recognition but not in visual discrimination and reversal touchscreen tasks. Social interactions in the male-female social dyad with USVs revealed social deficits on some but not all parameters. No repetitive behaviors were observed. Brains of adult Arid1b+/- mice had a smaller cerebellum and a larger hippocampus and corpus callosum. The corpus callosum increase seen here contrasts previous reports which highlight losses in corpus callosum volume in mice and humans.

LIMITATIONS

The behavior and neuroimaging analyses were done on separate cohorts of mice, which did not allow a direct correlation between the imaging and behavioral findings, and the transcriptomic analysis was exploratory, with no validation of altered expression beyond Arid1b.

CONCLUSIONS

This study represents a full validation and investigation of a novel model of Arid1b+/- haploinsufficiency throughout development and highlights the importance of examining both sexes throughout development in NDDs.

Common CHD8 Genomic Targets Contrast With Model-Specific Transcriptional Impacts of CHD8 Haploinsufficiency

The packaging of DNA into chromatin determines the transcriptional potential of cells and is central to eukaryotic gene regulation. Case sequencing studies have revealed mutations to proteins that regulate chromatin state, known as chromatin remodeling factors, with causal roles in neurodevelopmental disorders. Chromodomain helicase DNA binding protein 8 (CHD8) encodes a chromatin remodeling factor with among the highest de novo loss-of-function mutation rates in patients with autism spectrum disorder (ASD). However, mechanisms associated with CHD8 pathology have yet to be elucidated. We analyzed published transcriptomic data across CHD8 in vitro and in vivo knockdown and knockout models and CHD8 binding across published ChIP-seq datasets to identify convergent mechanisms of gene regulation by CHD8. Differentially expressed genes (DEGs) across models varied, but overlap was observed between downregulated genes involved in neuronal development and function, cell cycle, chromatin dynamics, and RNA processing, and between upregulated genes involved in metabolism and immune response. Considering the variability in transcriptional changes and the cells and tissues represented across ChIP-seq analysis, we found a surprisingly consistent set of high-affinity CHD8 genomic interactions. CHD8 was enriched near promoters of genes involved in basic cell functions and gene regulation. Overlap between high-affinity CHD8 targets and DEGs shows that reduced dosage of CHD8 directly relates to decreased expression of cell cycle, chromatin organization, and RNA processing genes, but only in a subset of studies. This meta-analysis verifies CHD8 as a master regulator of gene expression and reveals a consistent set of high-affinity CHD8 targets across human, mouse, and rat in vivo and in vitro studies. These conserved regulatory targets include many genes that are also implicated in ASD. Our findings suggest a model where perturbation to dosage-sensitive CHD8 genomic interactions with a highly-conserved set of regulatory targets leads to model-specific downstream transcriptional impacts.

Sociodemography of genital Chlamydia trachomatis in Coventry, UK, 1992-6

OBJECTIVE

To describe the sociodemographic and geographic risk factors for incident Chlamydia trachomatis genital infection.

DESIGN

Cross sectional retrospective study of cases diagnosed in local genitourinary clinics.

SETTING

Coventry, West Midlands, from 1992 to 1996.

SUBJECTS

582 female and 620 male Coventry residents aged 15-64 years diagnosed with one or more episodes of genital Chlamydia trachomatis infection by enzyme immunoassay. Subjects were assigned a Townsend deprivation score based on residence. The denominator population aged 15-64 years was derived from 1991 census data.

RESULTS

The mean annual incidence of genital chlamydia was 151 episodes (95% CI 140-163) per 100,000 population in men and 138 episodes (95% CI 128-149) per 100,000 population in women. Highest subgroup incidence was observed in 15-19 year old black women (2367 (95% CI 1370-4560) per 100,000), and 20-24 year old black men (1951 (95% CI 1158-3220) per 100,000). In univariate analyses, the most important risk factor for chlamydia infection in males was being black (incidence 1377 (95% CI 1137-1652) per 100,000 for black v 133 (95% CI 122-145) per 100,000 for white; RR 10.4, p < 0.0001) and for women was young age (incidence 475 (95% CI 415-540) per 100,000 for age group 15-19 years v 52 (95% CI 45-60) per 100,000 for age group 25-64 years; RR 9.1, p < 0.0001). In Poisson regression models of first episodes of genital chlamydia, for both males and females the effect of ethnic group could not be fully explained by socioeconomic confounding. There were significant interactions between age and ethnic group for both sexes and between age and level of deprivation for men. Geographical analysis revealed a high incidence of genital chlamydia in estates on the edge of the city as well as the urban core.

CONCLUSIONS

There is a complex interaction between geographical location, age, ethnic group, and social deprivation on the risk of acquiring genital Chlamydia trachomatis in Coventry. Better population based data are needed.

Penile intraepithelial neoplasia--a veiled lesion in genitourinary medicine

Penile intraepithelial neoplasia (PIN) is a clinically well known condition. However, its diagnosis is often difficult. We present four cases of PIN, seen in our department. Various histological patterns ranging from PIN I to PIN III were noted in these cases.

Drosophila EcR-B ecdysone receptor isoforms are required for larval molting and for neuron remodeling during metamorphosis

During the metamorphic reorganization of the insect central nervous system, the steroid hormone 20-hydroxyecdysone induces a wide spectrum of cellular responses including neuronal proliferation, maturation, cell death and the remodeling of larval neurons into their adult forms. In Drosophila, expression of specific ecdysone receptor (EcR) isoforms has been correlated with particular responses, suggesting that different EcR isoforms may govern distinct steroid-induced responses in these cells. We have used imprecise excision of a P element to create EcR deletion mutants that remove the EcR-B promoter and therefore should lack EcR-B1 and EcR-B2 expression but retain EcR-A expression. Most of these EcR-B mutant animals show defects in larval molting, arresting at the boundaries between the three larval stages, while a smaller percentage of EcR-B mutants survive into the early stages of metamorphosis. Remodeling of larval neurons at metamorphosis begins with the pruning back of larval-specific dendrites and occurs as these cells are expressing high levels of EcR-B1 and little EcR-A. This pruning response is blocked in the EcR-B mutants despite the fact that adult-specific neurons, which normally express only EcR-A, can progress in their development. These observations support the hypothesis that different EcR isoforms control cell-type-specific responses during remodeling of the nervous system at metamorphosis.

DHR3, an ecdysone-inducible early-late gene encoding a Drosophila nuclear receptor, is required for embryogenesis

Response to the steroid hormone ecdysone in Drosophila is controlled by genetic regulatory hierarchies that include eight members of the nuclear receptor protein family. The DHR3 gene, located within the 46F early-late ecdysone-inducible chromosome puff, encodes an orphan nuclear receptor that recently has been shown to exert both positive and negative regulatory effects in the ecdysone-induced genetic hierarchies at metamorphosis. We used a reverse genetics approach to identify 11 DHR3 mutants from a pool of lethal mutations in the 46F region on the second chromosome. Two DHR3 mutations result in amino acid substitutions within the conserved DNA binding domain. Analysis of DHR3 mutants reveals that DHR3 function is required to complete embryogenesis. All DHR3 alleles examined result in nervous system defects in the embryo.

Gonorrhoea in Coventry 1991-1994: epidemiology, coinfection and evaluation of partner notification in the STD clinic

The aim of this study is to analyse the epidemiology of gonorrhoea in the Coventry area between 1991-1994 and the implementation and outcome of partner notification. A total of 404 episodes in 382 patients comprised the study group. In Coventry, 97% of episodes were managed in the STD clinic. There was a decrease in female and heterosexual male cases from 172 cases in 1991 to 37 cases in 1994 and increase in homosexual male cases from 8 in 1991 to 13 in 1994 (P<0.0001). Chlamydial coinfection was found in 38%. Among patients with gonorrhoea, 33% were asymptomatic and 40% with gonorrhoea and chlamydia were asymptomatic. Ten per cent of index cases were asymptomatic as were 83% of contact cases (P<0.0001). The health advisers (HAs) interviewed 82% immediately and 94% at some time after diagnosis. Of the average 1.5 partners per patient identified, 0.31 partners per patient were already screened, another 0.4 partners per patient were traced, 0.37 partners per patient were not traced, and for 0.41 partners per patient notification outcome was unknown or unconfirmed. Partner notification of 278 index cases traced 163 primary or tertiary contacts, 115 were new cases of gonorrhoea.

Hepatitis B markers in heterosexual patients attending two genitourinary medicine clinics in the West Midlands

OBJECTIVE

To determine the prevalence of hepatitis B virus (HBV) infection in heterosexual patients attending two genitourinary medicine (GUM) clinics in the West Midlands and to examine whether heterosexual activity is a risk factor for acquiring HBV infection with the view to extend HBV vaccination policies to cover this group.

DESIGN

HBV markers were determined in the GUM study group and compared with that of the control groups. Responses to a questionnaire were used to examine sexual behaviour patterns that may be related to heterosexual acquisition of HBV infection.

SETTING

The West Midlands, UK April 1992-January 1993.

SUBJECTS

788 male patients and 688 female patients attending GUM clinics were compared with 498 male blood donors and 563 females attending antenatal clinics for the seroprevalence of HBV markers. Potential risk factors related to heterosexual activity were assessed in 1436 patients in the study group.

MAIN OUTCOME MEASURES

Prevalence of HBV markers in the GUM study group and the controls. The possible use of the risk factors examined as predictors for acquiring HBV infection.

RESULTS

The seroprevalence of hepatitis B core antibody (anti-HBc) in GUM patients was 1.9% and 0.5% in the control group. In the study groups the prevalence of anti-HBc from Birmingham was 3.2% while that from Coventry was 0.8%. The low seroprevalence of HBV prevented a multiple logistic analysis. A limited regression analysis showed that being non-white (p < 0.001) and duration of sexual activity (p = 0.013) were risk factors for HBV infection. However, these two factors were poor predictors of the risk to exposure to HBV infection.

CONCLUSION

The prevalence of HBV infection in heterosexual patients in the West Midlands is very low and does not provide any indications to broaden HBV vaccination into heterosexual patients attending GUM clinics. Risk factors were poor predictors of the exposure to HBV infection. This is partially due to the low prevalence of HBV infection in this study. Further studies are required before definitive conclusions are made regarding the potential predictive value of risk factors.

A survey on hepatitis B vaccination policies in genitourinary medicine in UK and Ireland

OBJECTIVE

To determine the policies applied in genitourinary medicine (GUM) departments in the United Kingdom (UK) and Ireland with regard to hepatitis B vaccination.

DESIGN

All genitourinary medicine consultants were sent a questionnaire requesting information concerning their selection criteria and the management of patients offered Hepatitis B vaccine. If no response was obtained a second questionnaire was sent. The survey was carried out in 1993.

SETTING

All genitourinary medicine departments in UK and Ireland.

PARTICIPANTS

234 consultants were sent the questionnaire. 153 consultants responded.

RESULTS

Overall, there was a 65.4% response rate to the questionnaire. Almost all genitourinary physicians would offer the vaccine to male homosexuals and up to 74% offer it to all male homosexuals, intravenous drug users (IVDU) and prostitutes. Of the genitourinary physicians, 96% agreed that hepatitis B virus (HBV) serological markers should be checked prior to or simultaneously with vaccination, yet there was no agreement as to which marker should be performed. Up to 79% of consultants recalled the patients to check their response to vaccination but only 61% offered long term follow up after vaccination.

CONCLUSION

HBV vaccine is offered to all male homosexuals, IVDU and prostitutes in GUM departments. Currently, the vaccine is not generally offered to patients who present with sexually transmitted diseases. Almost all genitourinary physicians (96%) agree that HBV serological markers should be checked prior to or simultaneously with the start of the vaccination course and 80% would request hepatitis B surface antibody levels after vaccination to identify inadequate responders and non-responders. From this survey, there appears to be a need for uniform post-vaccination HBV screening and timing and frequency of booster doses.

Warts in the oral cavity

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Prurigo nodularis in an HIV positive man

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Self sampling as part of screening for sexually transmitted diseases in clinic attenders. A preliminary study

Self sampling of the secretions of the female genital tract for microbiological investigations for Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis was assessed in female attenders of the genitourinary medicine clinic in Coventry and Warwickshire Hospital. The purpose of the study was to evaluate the possibility of offering this method of investigation to workers in the sex industry, who are reluctant to attend GUM Clinics. This Pilot Study aimed at assessing the feasibility and acceptability of self sampling of the secretions of the lower genital tract by female patients and its reliability in the detection of sexually transmitted infections. The analysis of the data from 75 participants, indicated that 7 infections were detected on patient sampling as compared to 11 on samples taken by a physician. Self sampling may prove a valuable alternative for the sex industry workers who are reluctant to attend GUM clinics.

Pediculosis pubis: a surrogate marker for sexually transmitted diseases

A review of all the patients diagnosed to have Pediculosis pubis (P pubis) during a 2 year period 1989-1991 was carried out. They constituted the index group and were compared with 140 consecutive patients seen during the month of June 1990, who served as controls. Both groups were comparable with respect to age and use of modern contraception. Coexisting sexually transmitted diseases (STDs) were found in 37% of the index group. Incidence of STDs was 51% among the controls. In the preceding 3 months, patients in the index group had significantly more sexual partners p < 0.005. These findings emphasize the need to offer full STD screening and health education to sexually active people who present with P pubis.

Management of cervical intraepithelial neoplasia in departments of genitourinary medicine--a national survey

A national survey of the methods used in the diagnosis and treatment of cervical intraepithelial neoplasia (CIN) in the departments of genitourinary medicine (GUM) in the United Kingdom had been conducted through a postal questionnaire. The findings indicate that at present of 157 responders to the questionnaire, 43 (27.3%) take an active part in the management of CIN. The different modes of management and follow-up are presented.

Balanitis (balanoposthitis) in patients attending a department of genitourinary medicine

Eighty-six patients with balanitis/balanoposthitis who presented at the department of genitourinary medicine in Coventry between October 1989 and August 1990 were investigated. While 34 (41%) cases had no specific aetiological factor Candida spp. accounted for 26 cases (30%), and group B beta haemolytic streptococci for 11 cases (13%) (one patient, a diabetic, was culture positive for both Candida spp. and group B beta haemolytic streptococci). The remaining 14 patients had other miscellaneous causes of balanitis/balanoposthitis.

The adolescent female prostitute and sexually transmitted diseases

Prostitution may be seen as an adolescent's cry for help. A review into the background of the problem, the groups and individuals involved and the incidence of sexually transmitted diseases amongst them is presented. Psychological analysis and behavioural trends, especially in relation to attitudes towards sex, sexually transmitted diseases and intravenous drug abuse are examined.

Labial adhesions after genital herpes infection

A case of genital herpes complicated by persistent labial adhesions is reported. As far as we know, this is the second such complication of genital herpes to be reported from this side of the Atlantic and only the third case documented world wide.

Rest pain and leg ulceration due to syphilitic osteomyelitis of the tibia

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