Genetic Diversity and Protective Efficacy of the RTS,S/AS01 Malaria Vaccine.

BACKGROUND: The RTS,S/AS01 vaccine targets the circumsporozoite protein of Plasmodium falciparum and has partial protective efficacy against clinical and severe malaria disease in infants and children. We investigated whether the vaccine efficacy was specific to certain parasite genotypes at the circumsporozoite protein locus. METHODS: We used polymerase chain reaction-based next-generation sequencing of DNA extracted from samples from 4985 participants to survey circumsporozoite protein polymorphisms. We evaluated the effect that polymorphic positions and haplotypic regions within the circumsporozoite protein had on vaccine efficacy against first episodes of clinical malaria within 1 year after vaccination. RESULTS: In the per-protocol group of 4577 RTS,S/AS01-vaccinated participants and 2335 control-vaccinated participants who were 5 to 17 months of age, the 1-year cumulative vaccine efficacy was 50.3% (95% confidence interval [CI], 34.6 to 62.3) against clinical malaria in which parasites matched the vaccine in the entire circumsporozoite protein C-terminal (139 infections), as compared with 33.4% (95% CI, 29.3 to 37.2) against mismatched malaria (1951 infections) (P=0.04 for differential vaccine efficacy). The vaccine efficacy based on the hazard ratio was 62.7% (95% CI, 51.6 to 71.3) against matched infections versus 54.2% (95% CI, 49.9 to 58.1) against mismatched infections (P=0.06). In the group of infants 6 to 12 weeks of age, there was no evidence of differential allele-specific vaccine efficacy. CONCLUSIONS: These results suggest that among children 5 to 17 months of age, the RTS,S vaccine has greater activity against malaria parasites with the matched circumsporozoite protein allele than against mismatched malaria. The overall vaccine efficacy in this age category will depend on the proportion of matched alleles in the local parasite population; in this trial, less than 10% of parasites had matched alleles. (Funded by the National Institutes of Health and others.).

Maximizing HIV Partner Notification Opportunities for Index Patients and their Sexual Partners in Malawi

Background. HIV testing and counselling (HTC) is important to effect positive sexual behaviour change and is an entry point to treatment; care; and psychosocial support. One of the most practical initiatives to increase HTC is to encourage sexual partners of HIV-infected persons to test for HIV. However; partner notification strategies must be feasible in the healthcare setting and acceptable to the population. Methods.We conducted a qualitative study during the pilot phase of an HIV partner notification trial to complement its assessment of feasibility and acceptability of methods of partner notification. We performed in-depth interviews with 16 consecutive HIV-positive index participants who consented and their 12 identifiable sexual partners. We also conducted two focus group discussions with healthcare workers to supplement the patient perspectives. In the main study; newly diagnosed HIV cases (index cases) were randomized to one of three methods of partner notification: passive; contract; and provider referral. Clients in the passive referral group were responsible for notifying their sexual partners themselves. Individuals in the contract referral group were given seven days to notify their partners; after which a healthcare provider contacted partners who had not reported for counselling and testing. In the provider group; a healthcare provider notified partners directly. Results.Although most index participants and partners expressed a preference for passive notification; they also highlighted benefits for provider-assisted notification and the universal right for all HIV-exposed persons to know their HIV exposure and benefit from HIV testing and access antiretroviral treatment. Several participants mentioned couples counselling as a way to diffuse tension and get accurate information. All mentioned benefits to HIV testing; including the opportunity to change behaviour. Conclusions. Provider-assisted partner notification is not preferred; but it is acceptable and may complement the passive method of notification. Couples counselling should also be encouraged

Interest in multipurpose prevention of HIV and pregnancy: perspectives of women, men, health professionals and community stakeholders in two vaginal gel studies in southern Africa.

OBJECTIVE: The pipeline of vaginal microbicides for HIV prevention has expanded to include products for multipurpose prevention, but the interests of potential users and those advising on use have not been sufficiently investigated. Rather, assumptions about interest in multipurpose prevention technologies (MPTs) are inferred from what is known about acceptability and use of microbicides or contraceptives. DESIGN AND SETTING: This paper presents data on concerns and preferences for multipurpose prevention of HIV and pregnancy. Data were collected in two microbicide gel studies in Malawi and Zimbabwe. Participants were women using candidate vaginal products, their male partners, health professionals and community stakeholders. METHODS: An individual interview was conducted with participants. Interviews were audio-recorded, transcribed, coded for content and analysed for key themes. RESULTS: Participants indicated strong interest in a vaginal HIV prevention product that could also prevent pregnancy. Reasons for this interest were convenience, problems with adverse effects with current contraceptive methods, concerns about long-term effects of contraceptives, and concerns about the health burdens of HIV infection during pregnancy. The main disadvantage of an MPT was recognition that while interest in preventing HIV is constant, contraceptive needs change over time. CONCLUSION: The study population indicated support for an MPT to prevent HIV and pregnancy. This support may be further strengthened if the product is also available for prevention of only HIV. Women and men will be more willing to use an MPT if they can be reassured that its use will have no long-term effect on fertility.

Exploring the Feasibility of Engaging Traditional Birth Attendants in a Prevention of Mother to Child HIV Transmission Program in Lilongwe; Malawi

Objective:To investigate the willingness of Traditional Birth Attendants (TBAs) to provide single dose antiretroviral prophylaxis to infants born to mothers with HIV and the feasibility of providing the TBAs with antiretroviral medication. Design 2 focus groups with a total of 17 registered TBAs. Setting Lilongwe; Malawi Methods TBAs were recruited by local health workers and participated in focus groups assessing their attitudes towards participation in a PMTCT program. Results TBAs were willing to participate in this prevention of mother-to-child HIV transmission (PMTCT) program and helped identify barriers to their participation. Conclusions:Given appropriate support and training; TBAs' participation in PMTCT programs could be an additional way to deliver medication to mothers and neonates who might otherwise miss crucial doses of medication

Utilization of family members to provide hospital care in Malawi: the role of Hospital Guardians.

AIM: Like most of sub-Saharan Africa, Malawi suffers from a paucity of human resources in the health sector. With an average of one physician for every 50,000 persons, and a health care professional to in-patient population ratio of 1:277, patient care suffers. At Kamuzu Central Hospital (KCH) of Lilongwe, Malawi, family members, termed Hospital Guardians, are utilized to provide basic care for patients. The aim of our study is to characterize this population and explore their role in the health care system of KCH. METHODS: Seventy three semi-qualitative surveys and nineteen in-depth interviews were conducted with hospital administrators, Guardians, nurses, and physicians from these wards. The results were analyzed using descriptive analysis and emergent coding. RESULTS: It was found that Hospital Guardians were primarily female family members of patients and have a low literacy rate. They performed a wide range of daily tasks in patient care from wound care to advocacy. Despite their essential role in the health care system, the Guardians were provided with little support from the hospital. There was often conflict between the Guardians and hospital personnel due to overcrowding with more than one Guardian per patient; a lack of understanding of hospital rules and regulations; and a lack of respect for the Guardian role by hospital staff. CONCLUSIONS: Until their role can be reduced by additional trained health care professionals, patient care could be improved by institutional support including a clarification of the role of the Hospital Guardians. Recommendations include a one-patient one-guardian policy; Guardian education; and enhancing Guardian resources.

Utilization of Family Members to Provide Hospital Care in Malawi: the Role of Hospital Guardians

Aim :Like most of sub-Saharan Africa; Malawi suffers from a paucity of human resources in the health sector. With an average of one physician for every 50;000 persons; and a health care professional to in-patient population ratio of 1:277; patient care suffers. At Kamuzu Central Hospital (KCH) of Lilongwe; Malawi; family members; termed Hospital Guardians; are utilized to provide basic care for patients. The aim of our study is to characterize this population and explore their role in the health care system of KCH. Methods Seventy three semi-qualitative surveys and nineteen in-depth interviews were conducted with hospital administrators; Guardians; nurses; and physicians from these wards. The results were analyzed using descriptive analysis and emergent coding. ResultsIt was found that Hospital Guardians were primarily female family members of patients and have a low literacy rate. They performed a wide range of daily tasks in patient care from wound care to advocacy. Despite their essential role in the health care system; the Guardians were provided with little support from the hospital. There was often conflict between the Guardians and hospital personnel due to overcrowding with more than one Guardian per patient; a lack of understanding of hospital rules and regulations; and a lack of respect for the Guardian role by hospital staff.Conclusions :Until their role can be reduced by additional trained health care professionals; patient care could be improved by institutional support including a clarification of the role of the Hospital Guardians. Recommendations include a one-patient one-guardian policy; Guardian education; and enhancing Guardian resources

Acceptance of repeat population-based voluntary counselling and testing for HIV in rural Malawi.

OBJECTIVE: To examine the acceptance of repeat population-based voluntary counselling and testing (VCT) for HIV in rural Malawi. METHODS: Behavioural and biomarker data were collected in 2004 and 2006 from approximately 3000 adult respondents. In 2004, oral swab specimens were collected and analysed using ELISA and confirmatory Western blot tests, while finger-prick rapid testing was done in 2006. We used cross-tabulations with chi(2) tests and significance tests of proportions to determine the statistical significance of differences in acceptance of VCT by year, individual characteristics and HIV risk. RESULTS: First, over 90% of respondents in each round accepted the HIV test, despite variations in testing protocols. Second, the percentage of individuals who obtained their test results significantly increased from 67% in 2004, when the results were provided in randomly selected locations several weeks after the specimens were collected, to 98% in 2006 when they were made available immediately within the home. Third, whereas there were significant variations in the sociodemographic and behavioural profiles of those who were successfully contacted for a second HIV test, this was not the case for those who accepted repeat VCT. This suggests that variations in the success of repeat testing might come from contacting the individuals rather than from accepting the test or knowing the results. CONCLUSIONS: Repeat HIV testing at home by trained healthcare workers from outside the local area, and with either saliva or blood, is almost universally acceptable in rural Malawi and, thus, likely to be acceptable in similar contexts.

Genotypic analysis of the protease and reverse transcriptase of HIV type 1 subtype C isolates from antiretroviral drug-naive adults in Malawi.

The protease (PR) and reverse transcriptase (RT) regions of HIV-1 isolates from 21 antiretroviral (ARV)-naive Malawian adults were sequenced and analyzed to determine the prevalence of drug resistance-associated mutations in this population. Phylogenetic analysis confirmed that all isolates grouped with HIV-1 subtype C, the predominant subtype in Malawi. No major mutations associated with resistance to PR inhibitors (PIs), nucleoside RT inhibitors (NRTIs), or nonnucleoside RT inhibitors (NNRTIs) were found. In contrast, accessory mutations were found in the protease region at positions 10, 20, 36, 63, 77, and 93, and in the RT region at positions 118, 211, and 214. Further studies will be needed to determine the clinical impact of these polymorphisms on viral susceptibility to existing antiretroviral drugs.

Blockage of the rete testis and efferent ductules by ectopic Sertoli and Leydig cells causes infertility in Dax1-deficient male mice.

DAX-1, an X-linked member of the orphan nuclear receptor superfamily of transcription factors, plays a key role in sex determination and gonadal differentiation. Dax1-deficient male mice are infertile and have small testes despite normal serum levels of T and gonadotropins. Examination of Dax1-deficient testes reveals dilated seminiferous tubules and abnormal parameters of sperm fertilizing capability consistent with a possible obstruction in the testis. To test this hypothesis, we performed a comprehensive evaluation of the male reproductive tract in Dax1-deficient mice. Light and electron microscopic examination revealed the rete testis is blocked by aberrantly located Sertoli cells, creating a tailback of necrosing sperm in the testis. Sertoli cells also obstruct the proximal and middle efferent ductules, and this is accompanied by an overgrowth of the efferent duct epithelium. Seminiferous tubules close to the rete testis contain ectopic Leydig cells, distinct from the hyperplastic Leydig cells present in the interstitial space. The peritubular tissue surrounding these tubules is frequently abnormal, containing relatively undifferentiated myoid cells and no basement membrane between the myoid cells and Sertoli cells. A third of aged (>1-yr-old) Dax1-deficient male mice develop sex cord-stromal tumors, derived from cells of the Sertoli/granulosa cell or Leydig cell lineages. Combined, these observations reveal abnormal differentiation and proliferation of Leydig cells and Sertoli cells in Dax1-deficient male mice, leading to obstruction of the rete testis and infertility.

C-Kit mutant mice have a selective loss of vagal intramuscular mechanoreceptors in the forestomach.

Intramuscular arrays are one of two major classes of vagal afferent mechanoreceptors that innervate the smooth muscle wall of the proximal gastrointestinal tract. They consist of rectilinear telodendria that distribute in the muscle sheets, parallel to the long axes of muscle fibers. Intramuscular arrays appear to make direct contact with the muscle fibers, but they also course on, and form appositions with, intramuscular interstitial cells of Cajal. These complexes formed by intramuscular arrays and intramuscular interstitial cells of Cajal suggest that intramuscular arrays might require either structural or trophic support of the interstitial cells of Cajal for normal differentiation and/or maintenance. To evaluate this hypothesis, we have examined the morphology and distribution of vagal afferent endings in the c-Kit mutant mouse that lacks intramuscular interstitial cells of Cajal. Vagal afferents were labeled by nodose ganglion injection of either wheat germ agglutinin-horseradish peroxidase conjugate or a tagged dextran, and the labeled afferent terminals in the stomach were mapped using a standardized quantitative sampling scheme. Intramuscular arrays were dramatically reduced (in circular muscle by 63%; in longitudinal muscle by 78%) in the c-Kit mutant mice relative to their wild-type littermates. Additionally, a substantial number of the surviving axons and terminals in the mutant stomachs were morphologically aberrant. Moreover, the loss of intramuscular arrays in mutants appeared to be selective: the structure, distribution and density of intraganglionic laminar endings, i.e., the other vagal mechanoreceptors in smooth muscle, were not significantly altered. Finally, the conspicuous decrease in intramuscular array density in mutants was associated with a non-significant trend toward loss of nodose ganglion neurons. Collectively these findings suggest that interstitial cells are required for the normal development or maintenance of vagal intramuscular arrays. Therefore, the c-Kit mutant mouse will be valuable for determining the role(s) of interstitial cells in intramuscular array development as well as for providing an animal model with the intramuscular array class of vagal afferents selectively ablated.

Adenovirus-mediated targeted expression of toxic genes to adrenocorticotropin-producing pituitary tumors using the proopiomelanocortin promoter.

Management of Cushing's disease remains challenging, despite advances in its diagnosis and treatment. Here, we describe a strategy for targeting the expression of toxic genes to ACTH-producing tumor cells using adenoviral vectors. The POMC promoter was used to express either a marker gene (beta-galactosidase) or a toxic gene [herpes simplex virus thymidine kinase (TK)]. In ACTH-producing AtT20 cells, infection with recombinant adenoviruses containing the POMC promoter (AdPOMCGal; AdPOMCTK) led to high-level gene expression. Stereotactic injection of AdPOMCGal into the rat pituitary resulted in localized expression of the beta-galactosidase transgene in corticotrope cells. Cytotoxicity studies were performed using the TK-containing vectors and treatment with ganciclovir. AdPOMCTK caused greater than 95% cytotoxicity of AtT20 cells at a viral dose (multiplicity of infection, 5 plaque-forming units/cell) that induced minimal toxicity using control viruses. No cellular toxicity was seen using a nonpituitary cell line (T47D breast tumor cells). AtT20 cells transplanted into nude mice induced features of Cushing's syndrome and were used as an in vivo model of ACTH-producing tumors. Injection of the AdPOMCTK virus caused significant regression of the transplanted AtT20 tumors. These studies suggest that the POMC promoter may provide a useful gene therapy strategy for the adjunctive treatment of pituitary tumors causing ACTH-dependent Cushing's syndrome.

Gastrointestinal projection maps of the vagus nerve are specified permanently in the perinatal period.

The vagal innervation of the proximal gastrointestinal (GI) tract is lateralized. To determine whether this pattern is specified as early as the perinatal period, neonatal rat pups were given unilateral cervical vagotomies. Separate groups received (1) transections below the left nodose ganglion, (2) left cervical resections that included removal of the nodose ganglion, or (3) sham surgeries. At 4 months of age, each animal's vagal afferent projections from the unoperated side were mapped by injecting the nodose with WGA-HRP, preparing the stomach as wholemounts, and processing the tissue with tetramethyl benzidine. The two types of vagal afferent endings in GI smooth muscle, namely intraganglionic laminar endings and intramuscular arrays, were surveyed separately, and their regional distributions were mapped. Changes in the nucleus of the solitary tract (NST) and dorsal motor nucleus of the vagus (DMNX) were assessed with cell counts and area measurements. Neonatal loss of the vagus innervating one side of the GI tract, with or without ganglionectomy, did not cause the unoperated vagus to sprout to the denervated side. In addition, removal of the projections to the one side of the target organ did not produce a reorganization of the projection maps of the unoperated vagus within its normal or ipsilateral wall of the GI tract. Although the regional patterns of the unoperated ipsilateral vagus were not affected, the packing densities of both types of afferents supplied by this trunk were moderately reduced. The DMNX of the vagotomized side displayed extensive (approximately 83%) neuronal loss; the DMNX on the unoperated side as well as the NST on both sides exhibited limited (approximately 20--25%) losses. The lack of a peripheral projection field reorganization -- except for a moderate down-regulation -- after complete unilateral denervation suggests that both the laterality and the afferent terminal phenotypes (or target tissues) of the vagus in the proximal GI tract are specified by postnatal day one in the rat. The present results, taken together with other observations, also suggest that three different combinations of signals orchestrate the commitments of vagal afferents respectively to (1) the side of the organ, (2) the region within the organ wall, and (3) the accessory and innervated tissues that complex with the fully differentiated ending.

Driver's license and voter registration lists as population-based sampling frames for rural African Americans.

PURPOSE: To compare coverage of a state driver's license list and county voter registration lists as frames for sampling rural African Americans. METHODS: Name, birth date, sex, and county were extracted from records for all 18--59 year-old African Americans residing in eight rural North Carolina counties and listed in the North Carolina Driver license file [obtained as a SAS dataset from the University of North Carolina (UNC) Highway Safety Research Center] and in machine-readable text files of registered voters (obtained from county boards of elections). Files were edited, merged, and matched by last name and date of birth to produce three files for each five-year age group, sex, and county: 1) persons listed only in the driver's file; 2) persons listed only in the voter's file; and 3) persons listed in both. RESULTS: The median percentages of unique persons found only on the driver's list, only on the voter's list, and on both lists were 54%, 17%, and 30% men, and 35%, 25%, and 41% women, respectively. CONCLUSIONS: The driver's list provided better coverage than did voter registration lists. Federal legislation that prohibits states from releasing driver's license lists for use in surveys removes a valuable resource for population-based research.

Sertoli cell-specific rescue of fertility, but not testicular pathology, in Dax1 (Ahch)-deficient male mice.

DAX1 is an orphan member of the nuclear hormone receptor superfamily of transcription factors. Our recent characterization of Dax1 (Ahch)-deficient male mice revealed a primary testicular defect resulting in hypogonadism and sterility. The progressive degeneration of the germinal epithelium, independent of abnormal gonadotropin and testosterone production, suggested an intrinsic loss of Dax1 function in the Sertoli cells. To test this hypothesis, we assessed the effect of Sertoli cell-specific expression of a human DAX1 (AHC) transgene driven using the promoter of the Müllerian inhibiting substance (MIS) gene. The MIS-DAX1 transgene partially rescued the mutant phenotype of the Dax1-deficient male mice. Although testicular morphology remained abnormal, fertility was restored to levels matching that of wild-type littermates. Examination of several markers of sperm fertilizing capability revealed significant improvements in MIS-DAX1-rescued mice. Epididymal sperm count and sperm motility were greater in 12-week-old rescued mice than in age-matched Dax1-deficient mice. The ability of sperm to undergo an immediate acrosome reaction was impaired in Dax1-deficient animals, and sperm from Dax1-deficient mice fertilized only 8.2 +/- 6.8% of eggs in vitro, significantly less than rescue (67.8 +/- 19.1%) and wild-type (88.9 +/- 3.9%) sperm. These results indicate that Dax1 expression in Sertoli cells is adequate to overcome crucial thresholds related to sperm production and function. However, the failure to completely rescue the testicular pathology of Dax1-deficient mice suggests that Dax1 expression in other somatic cells is essential for normal testicular development.

Social context of sexual relationships among rural African Americans.

BACKGROUND: Reasons for the strikingly increased rates of HIV and other sexually transmitted infections (STIs) among African Americans in the rural Southeastern United States remain unclear. Investigators have devoted little attention to the potential influence of the social and economic context on sexual behaviors. GOAL: To examine the potential influence of these contextual factors on behaviors that promote the transmission of STIs. STUDY DESIGN: Focus group interviews in which African Americans from rural North Carolina discussed life in their communities and contextual factors affecting sexual behavior. RESULTS: Respondents reported pervasive economic and racial oppression, lack of community recreation, boredom, and resultant substance abuse. Many perceived a shortage of black men because of their higher mortality and incarceration rates compared with whites, and believed this male shortage to be partly responsible for the concurrent sexual partnerships that they perceived as widespread among unmarried persons. CONCLUSION: Contextual features including racism, discrimination, limited employment opportunity, and resultant economic and social inequity may promote sexual patterns that transmit STIs.

Adenovirus-directed expression of dominant negative estrogen receptor induces apoptosis in breast cancer cells and regression of tumors in nude mice.

BACKGROUND: Estrogen receptors (ER) are expressed in about two thirds of human breast cancer, and are an important pharmacological target for treatment of these tumors. Dominant negative forms of the ER have been suggested as an alternative method to disrupt ER function. In this study, we examined the effect of dominant negative ER mutants (ER1-536 and L540Q) on ER-positive breast cancer cells in vitro and in vivo. MATERIALS AND METHODS: ER-positive T47D breast cancer cells were infected with adenoviral vectors expressing ER1-536 and L540Q to examine the effects of the mutants on gene expression and cell growth. Adenoviral vectors containing the wild type ER (AdwtER) and beta-galactosidase gene (AdGal) were used as controls. RESULTS: Ad1-536 or AdL540Q infection inhibited T47D cell growth and induced apoptosis, increasing Bax protein and phosphorylation of p38 mitogen-activated-protein kinase (MAPK). Consistent with the apoptotic effects in vitro, pre-infection of T47D cells with Ad1-536 or AdL540Q inhibited tumor formation when these cells were introduced into nude mice. In addition, injection of Ad1-536 and AdL540Q into pre-established T47D tumors induced tumor regression. Apoptosis, in conjunction with the activation of caspase-3 and phosphorylation of p38 MAPK, was detected in the shrinking tumors. Overexpression of wild-type ER by AdwtER infection also produced antiproliferative and apoptotic effects, but to a lesser extent than the ER1-536 and L540Q mutants. CONCLUSIONS: These results indicate that dominant negative ER mutants have the potential to induce apoptosis of T47D cells and regression of tumors. The delivery of dominant negative ERs by adenoviral vectors may provide a useful tool for targeted therapy of ER-positive breast cancer.

Vagal afferent innervation of smooth muscle in the stomach and duodenum of the mouse: morphology and topography.

Intraganglionic laminar endings (IGLEs) and intramuscular arrays (IMAs), the two putative mechanoreceptors that the vagus nerve supplies to the gastrointestinal smooth muscle, have been characterized almost exclusively in the rat. To provide normative inventories of these afferents for the mouse, the authors examined the endings in the stomach and small intestine of three strains used as backgrounds for gene manipulations (i.e., C57, 129/SvJ, and WBB6). Animals received nodose ganglion injections of wheat germ agglutinin-horseradish peroxidase or dextran-tetramethylrhodamine conjugated to biotin. The horseradish peroxidase tissue was processed with tetramethylbenzidine and was used to map the distributions and densities of the two endings; the dextran material was counterstained with c-Kit immunohistochemistry to assess interactions between intramuscular arrays and interstitial cells of Cajal. IGLEs and IMAs constituted the vagal innervation of mouse gastric and duodenal smooth muscle. IGLE morphology and distributions, with peak densities in the corpus-antrum, were similar in the three strains of mice and comparable to those observed in rats. IMAs varied in complexity from region to region but tended to be simpler (fewer telodendria) in mice than in rats. IMAs were most concentrated in the forestomach and sphincters in mice, as in rats, but the topographic distributions of the endings varied both between strains of mice (subtly) and between species (more dramatically). IMAs appeared to make appositions with both interstitial cells and smooth muscle fibers. This survey should make it practical to assay the effects of genetic (e.g., knockout) and experimental (e.g., regeneration) manipulations affecting visceral afferents and their target tissues.

A dominant negative CREB (cAMP response element-binding protein) isoform inhibits thyrocyte growth, thyroid-specific gene expression, differentiation, and function.

cAMP mediates the effects of TSH by regulating thyroid follicular cell proliferation, differentiation, and function. To assess the functional importance of the cAMP response element binding protein (CREB) in thyroid follicular cell regulation in vivo, we targeted the expression of a dominant negative (DN) CREB isoform to the thyroid glands of transgenic mice using a tissue-specific promoter. Transgenic mice exhibited severe growth retardation and primary hypothyroidism. Serum levels of TSH were elevated 8-fold above normal levels, and T4 and T3 levels were low. Histologically, the mutant thyroid glands were characterized by poorly developed follicles that were heterogeneous in size with diminished colloid. Ciliated thyroid epithelial cells were observed in the transgenic thyroid glands, suggesting a failure of follicular cell differentiation. Consistent with this hypothesis, the DN CREB transgene inhibited the expression of an array of genes including thyroglobulin, thyroperoxidase, and the TSH receptor in semiquantitative RT-PCR experiments. Altered expression of the thyroid transcription factors Pax-8, TTF-1, and TTF-2 was also observed. These results demonstrate a critical role for CREB in thyroid growth, differentiation, and function in vivo.

Hepatitis E virus seroprevalence in children living in rural Ghana.

Large outbreaks of hepatitis E virus have been reported in warm climates with poor sanitation although it exists in endemic form in these areas too. This oro-fecally transmitted infection has been described mainly in adults with very little data from children. This study looked at seroprevalence in children resident in a rural district in Ghana with very little pipe-borne water supply. Sera from 803 randomly selected pupils aged 6-18 years were evaluated for anti-HEV. The overall seroprevalence was 4.4% with seroprevalence increasing from 1% in 6-7 year olds to 8.1% in 16-18 year olds. Females had a significantly higher seroprevalence than males. Anti-seroprevalence was also not influenced by the presence of hepatitis B and C virus markers. Anti-HEV seroprevalence was however, far lower than suspected seroprevalence of hepatitis A virus which is also transmitted oro-fecally. The short life of anti-HEV may be responsible for this low seroprevalence.