HIV epidemic in Central African Republic: high prevalence rates in both rural and urban areas

A sentinel serosurveillance study was conducted in Central African Republic to estimate the prevalence of HIV seropositivity in the general adult population in each province so that the public health authorities can target HIV prevention programmes to the priority areas. Blood samples were collected from women attending 48 antenatal clinics in urban and rural areas of the Central African Republic. These samples were tested for HIV antibodies in an anonymous and unlinked manner using strategy II recommended by WHO. The data were extrapolated to all women of reproductive age in Central African Republic by use of a parity-based adjustment involving the application of correction factors to the observed prevalence rates. A total of 9,305 pregnant women were recruited from November 2001 to October 2002. HIV seroprevalence was high in all age groups (12% in the less than 20 year age group to 17% in the 25-29 year age group). The median prevalence of HIV in antenatal clinics was similar for rural areas, for Bangui and for other urban areas (16.5, 15.0, and 12.5% respectively). Adjustment for parity and fertility pattern increased the prevalence of HIV in all antenatal clinics except in Bangui. This first national study of HIV prevalence in Central African Republic revealed that the HIV epidemic is continuing to spread in both urban and rural areas. Thus, efforts to reduce transmission should be made in every part of the country.     

Retinoids and spermatogenesis: lessons from mutant mice lacking the plasma retinol binding protein.

Using Rbp4-null mice as models, we have established for the first time the kinetics of the spermatogenetic alterations during vitamin A deficiency (VAD). Our data demonstrate that the VAD-induced testicular degeneration arises through the normal maturation of germ cells in a context of spermatogonia differentiation arrest. They indicate that retinoic acid (RA) appears dispensable for the transition of premeiotic to meiotic spermatocytes, meiosis, and spermiogenesis. They confirm that RA plays critical roles in controlling spermatogonia differentiation, spermatid adhesion to Sertoli cells, and spermiation, and suggest that the VAD-induced arrest of spermatogonia differentiation results from simultaneous blocks in RA-dependent events mediated by RA receptor gamma (RARgamma) in spermatogonia and by RARalpha in Sertoli cells. They also provide evidence that expression of major RA-metabolizing enzymes is increased in mouse Sertoli cells upon VAD and that vitamin A-deficient A spermatogonia differ from their RA-sufficient counterparts by the expression of the Stra8 gene.     

HIV infection rapidly induces and maintains a substantial suppression of thymocyte proliferation

The supply of naive T cells by the thymus normally requires precursor T cell proliferation within the thymus and would be particularly important in the setting of HIV infection when both naive and memory T cells are progressively depleted. As a robust, quantitative index of intrathymic proliferation, the ratio of different T cell receptor excision circles (TRECs), molecular markers of distinct T cell receptor rearrangements occurring at different stages of thymocyte development, was measured in peripheral blood-mononuclear cells (PBMCs). This ratio has the virtue that it is a "signature" of thymic emigrants throughout their entire life and, thus, can be measured in peripheral cell populations that are easy to obtain. Using the new assay, we evaluated the effect of HIV infection on intrathymic precursor T cell proliferation by longitudinal analysis of PBMCs from recently infected individuals. Our findings reveal a substantial reduction in intrathymic proliferation. The analysis also indicates the existence of a compensatory mechanism acting to sustain the numbers of recent thymic emigrants (RTEs) in the periphery.     

Case report and review of septicemia due to Serratia ficaria.

Serratia ficaria was first described in 1979 as part of the fig tree ecosystem (P.A.D. Grimont, F. Grimont, and M. P. Starr, Curr. Microbiol. 2:277-282, 1979). Since then, it has been isolated from clinical specimens from a few human patients (C. Bollet, J. Freney, P. de Micco, F. Grimont, and P.A.D. Grimont, Méd. Mal. Infect. 20:97-100, 1990; J.A. Brouillard, W. Hansen, and A. Compere, J. Clin. Microbiol. 19:902-904, 1984; H. Darbas, H. Jean-Pierre, G. Boyer, and M. Riviere, Méd. Mal. Infect. 23:269-270, 1993; V.J. Gill, J.J. Farmer, III, P.A.D. Grimont, M.A. Asbury, and C.L. McIntosh, J. Clin. Microbiol. 14:234-236, 1981; F.D. Pien and J.J. Farmer III, South. Med. J. 76:1591-1592, 1983; C. Richard, J. de Coquet, and C. Suc, Méd. Mal. Infect. 19:45-47, 1989), but the pathogenicity of S. ficaria was always questionable. We are reporting the case of an aged cancer patient who developed S. ficaria septicemia. The habitat of this organism and its potential role as a pathogen are discussed.     

Reciprocal translocation mosaicism in man

We report on an8-month-old girl with a de novo 5q/6q autosomal translocation with loss of the distal part of the long arm of chromosome 6 (6q23.3→6qter); clinical manifestations are peculiar craniofacial stigmata, truncal obesity and persisting hypotonia. The similarity with a previously reported patient with 6q interstitial deletion is discussed.     

CpG island methylation in aberrant crypt foci of the colorectum

Aberrant crypt foci (ACF) are postulated to be the earliest precursor lesion in colorectal carcinogenesis, and CpG island methylation has been described as an important molecular pathway. We therefore studied methylation in ACF from patients with familial adenomatous polyposis (FAP) or sporadic colorectal cancer. We assessed methylation status of the p16 tumor suppressor gene, MINT1 (methylated in tumor 1), MINT2, MINT31, O(6)-methylguanine-DNA methyltransferase gene, and hMLH1 mismatch repair gene. We compared methylation to ACF histopathology, K-ras proto-oncogene mutation, loss of heterozygosity at chromosome 1p, and microsatellite instability. Methylation was present in 34% (21 of 61) of ACF, including both FAP and sporadic types, but was more frequent in sporadic ACF [53% (18 of 34) versus 11% (3 of 27), P = 0.002], especially dysplastic sporadic ACF [75% (3 of 4) versus 8% (2 of 24), P = 0.004]. MINT31 was more frequently methylated in heteroplastic ACF than dysplastic ACF [35% (11 of 31) versus 7% (2 of 30), P = 0.01]. Strong associations of ACF methylation with K-ras mutation (P = 0.007) and with loss of chromosome 1p (P = 0.04) were observed, but methylation was the only molecular abnormality identified in 16% (10 of 61) of ACF. Our findings suggest that methylation in ACF is an early event in the pathogenesis of a subset of colorectal carcinomas, and that ACF from FAP patients and patients with sporadic colorectal cancer have distinct epigenetic changes that reflect differences in molecular pathogenesis.     

Marden-Walker syndrome: case report, literature review and nosologic discussion

Schrander-Stumpel C, de Die-Smulders C, de Krom M, Schyns-Fleuren S, Hamel B, Jaeken D, Fryns J-P. Marden-Walker syndrome: case report, literature review and nosologic discussion.
Clin Genet 1993: 43: 303–308. © Munksgaard, 1993
The Marden-Walker syndrome is characterized by psychomotor retardation, a mask-like face with blepharophimosis, micrognathia and a high-arched or cleft palate, low-set ears, kyphoscoliosis and joint contractures. We report on a male patient with the clinical features of the syndrome. In addition, he had a Dandy-Walker malformation with hydrocephalus and vertebral abnormalities. During pregnancy, there were feeble fetal movements and polyhydramnios. We propose that Marden-Walker syndrome is one of the etiologic possibilities in children with the heterogeneous fetal a(hypo)kinesia deformation sequence (FADS). Differential diagnosis is discussed. The etiology is probably heterogeneous.     

Feeling what you hear: auditory signals can modulate tactile tap perception

We tested whether auditory sequences of beeps can modulate the tactile perception of sequences of taps (two to four taps per sequence) delivered to the index fingertip. In the first experiment, the auditory and tactile sequences were presented simultaneously. The number of beeps delivered in the auditory sequence were either the same as, less than, or more than the number of taps of the simultaneously presented tactile sequence. Though task-irrelevant (subjects were instructed to focus on the tactile stimuli), the auditory stimuli systematically modulated subjects tactile perception; in other words subjects responses depended significantly on the number of delivered beeps. Such modulation only occurred when the auditory and tactile stimuli were similar enough. In the second experiment, we tested whether the automatic auditory-tactile integration depends on simultaneity or whether a bias can be evoked when the auditory and tactile sequence are presented in temporal asynchrony. Audition significantly modulated tactile perception when the stimuli were presented simultaneously but this effect gradually disappeared when a temporal asynchrony was introduced between auditory and tactile stimuli. These results show that when provided with auditory and tactile sensory signals that are likely to be generated by the same stimulus, the central nervous system (CNS) tends to automatically integrate these signals.     

Physicochemical model of alginate-poly-L-lysine microcapsules defined at the micrometric/nanometric scale using ATR-FTIR, XPS, and ToF-SIMS

Alginate-poly-L-lysine-alginate (APA) microcapsules are currently being investigated as a means to immuno-isolate transplanted cells, but their biocompatibility is limited. In this study, we verified the hypothesis that poly-L-lysine (PLL), which is immunogenic when unbound, is exposed at the APA microcapsule surface. To do so, we analysed the microcapsule membrane at the micrometric/nanometric scale using attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. The results indicate that PLL and alginate molecules interact within the membrane. PLL exists in considerable amounts near the surface, contributing to the majority of the carbon within the outermost 100 Angstroms of the membrane. PLL was also detected at the true surface (the outermost monolayer) of the microcapsules. The exposure of PLL does not appear to result from defects in the outer alginate coating. This physicochemical model of APA microcapsules could explain their immunogenicity and will play an important role in the optimization of the microcapsule design.