Angiotensin-1-converting enzyme (ACE) plasma concentration is influenced by multiple ACE-linked quantitative trait nucleotides

Circulating angiotensin-1-converting enzyme (ACE) is a highly heritable trait, and a major component of the genetic variance maps to the region of the ACE gene. The strong effect of the locus, and the interest in ACE as a candidate gene for cardiovascular disorders, has led to extensive investigation of its relationship to the ACE phenotype, providing one of the most complete examples of quantitative trait locus (QTL) analysis in humans. Resequencing of ACE followed by haplotype analysis in families of British and French origin has shown that the genetic variants that are primarily associated with the ACE trait map to an 18 kb interval flanked by two intragenic, ancestral recombination breakpoints. This critical interval contains dozens of ACE-associated variants in Caucasians, but identification of which of these directly influence ACE concentration is ambiguous because of the almost complete linkage disequilibrium in European populations. In a complementary sequencing and genotyping study of individuals from West African families, we show that this population has much greater haplotype diversity across the gene. Through analysis of the contrasting relationships of the trait phenotype with haplotypes that carry different allelic combinations from those observed in Caucasians, we demonstrate that (at least) two major intragenic sites within the critical interval and (at least) one minor promoter site are associated with the ACE quantitative trait through additive effects. These results point to the importance of analysing diverse populations with different gene genealogies in gene-association studies.     

Delineation of an estimated 6.7 MB candidate interval for an anophthalmia gene at 3q26.33-q28 and description of the syndrome associated with visible chromosome deletions of this region

Anophthalmia or microphthalmia occur in approximately one in 10 children who have severe visual impairment. These eye malformations are often of unknown aetiology, but can be inherited in autosomal dominant, recessive or X-linked forms, and can also occur in association with specific chromosome abnormalities. Four children are described in the medical literature with microphthalmia or anophthalmia in association with chromosome rearrangements involving distal 3q, suggesting the presence of a micro/anophthalmia gene in this region. We have identified two further patients with micro/anophthalmia and chromosome rearrangements involving 3q26-->3q27 and identified a 6.7 MB common deleted region. Patient 1 had multiple abnormalities including bilateral anophthalmia, abnormalities of the first and second cranial nerves and partial absence of the corpus callosum. His karyotype was 46,XY,del(3)(q26.33q28). Patient 2 had right anophthalmia and left extreme microphthalmia. Her karyotype was 46,XX,del(3)(q26.33q28)t(3;7)(q28;q21.1). Both patients had intrauterine growth retardation (IUGR) and strikingly similar dysmorphic facies consisting of bossed forehead, downward-slanting palpebral fissures, grooved bridge of the nose, prominent low-set ears, small down-turned mouth and small mandible. We identified BAC clones mapping to distal 3q from the ENSEMBL and NCBI Entrez databases. These BAC clones were used as fluorescence in situ hybridisation (FISH) probes to identify the minimum deleted region common to both patients. This interval, between clones RPC11-134F2 and RPC11-132N15, was estimated to be 6.7 MB. We conclude that there is an anophthalmia locus within this interval. Candidate genes mapping to this region include Chordin and DVL3, a homologue of the Drosophila Dishevelled gene.     

Genetic and physical characterization of the early-onset Alzheimer's disease AD3 locus on chromosome 14q24.3

Genetic linkage studies have provided significant evidence thata major gene defect, AD3, for familial early-onset Alzheimer'sdisease (EOAD) is located at chromosome 14q24.3, between theshort tandem repeat (STR) markers D14S52 and D14S53 defininga genetic size of 22.7 cM for the AD3 candidate region. We constructeda physical map of the AD3 region using yeast artificial chromosomes(YACs) selected from both the CEPH and megaCEPH YAC librariesusing the AD3 linked STR markers as well as new sequence-taggedsites (STSs) designed based on YAC terminal sequences. The YACmap is contiguous in the region between D14S258 and D14S53,a region of 8.2 cM, and has an estimated physical size of 4–8Mb. The YAC contig map was used as a framework to localize threeknown genes, a pseudogene and two brain expressed sequence tags(ESTs). Linkage analysis studies in two Belgian chromosome 14EOAD families AD/A and AD/B, identified obligate recombinantsin family AD/A with D14S289 and D14S61 reducing the geneticsize of the candidate AD3 region substantially. The minimalAD3 candidate region measured 6.4 cM on the genetic map andis contained within six overlapping megaCEPH YACs that covereda physical distance estimated between 2 and 6 Mb. These YACsas well as other YACs in the YAC contig map are valuable resourcesin gene cloning efforts or genomic sequencing experiments aimingat isolating the AD3 gene.     

Four-color flow cytometric analysis of peripheral blood donor cell chimerism

Passenger leukocytes have been demonstrated to play significant roles in initiating and also regulating immune reactions after organ transplantation. Reliable techniques to detect donor leukocytes in recipients after organ transplantation are essential to analyze the role, function, and behavior of these leukocytes. In this report we describe a simple, reliable method to detect donor cells with low frequencies using peripheral blood samples. Detection of small numbers of major histocompatibility complex (MHC) mismatched cells was first studied using four-color flow cytometry in artificially created cell mixtures. By selecting the CD45(+) population and simultaneous staining with several leukocyte lineage markers (CD3, CD4, CD8, CD56, and CD19), MHC-mismatched leukocytes were consistently detected in cell suspensions prepared from directly stained whole blood samples with a threshold sensitivity as low as 0.1%-0.2%. When the fresh peripheral blood mononuclear cells were separated by conventional Ficoll gradient purification, similar, but slightly lower levels of donor cells were detected. Blood samples obtained 1-5 months after liver, kidney, and intestine transplants revealed that the kind of organ allograft influenced levels and lineage pattern of the circulating donor cells. This procedure provided a simple and reliable method in determining early chimerism in transplant recipients. However, the detection of MHC-mismatched leukocytes of all lineages was much lower when frozen peripheral blood mononuclear cells were used.     

Decreased depression up to one year following CBSM+ intervention in depressed women with AIDS: the smart/EST women's project

This prospective multisite Phase III clinical trial (Miami, New York, New Jersey) investigated the long-term (one year) effects of a 10-week group cognitive-behavioral stress management/expressive supportive therapy (CBSM+) intervention on disadvantaged minority women living with AIDS. The CBSM+ intervention consisted of 10-weekly group session of stress management, cognitive-behavioral skill training, relaxation techniques and expressive-supportive therapeutic strategies. The primary study outcome was self-reported depression scores as measured by the BDI. The CBSM+ Group intervention significantly decreased depression scores on the BDI for women following the intervention and maintained the decreased level at one-year follow-up.     

Multiscale structure of sheet nacre

This work was conducted on Pinctada maxima nacre (mother of pearl) in order to understand its multiscale ordering and the role of the organic matrix in its structure. Intermittent-contact atomic force microscopy with phase detection imaging reveals a nanostructure within the tablet. A continuous organic framework divides each tablet into nanograins. Their shape is supposed to be flat with a mean extension of 45nm. TEM performed in the darkfield mode evidences that at least part of the intracrystalline matrix is crystallized and responds like a 'single crystal'. The tablet is a 'hybrid composite'. The organic matrix is continuous. The mineral phase is thus finely divided still behaving as a single crystal. It is proposed that each tablet results from the coherent aggregation of nanograins keeping strictly the same crystallographic orientation thanks to a hetero-epitaxy mechanism. Finally, high-resolution TEM performed on bridges from one tablet to the next, in the overlying row, did not permit to evidence a mineral lattice but crystallized organic bridges. The same organic bridges were evidenced by SEM in the interlaminar sequence.     

Dysfunction of axonemal dynein heavy chain Mdnah5 inhibits ependymal flow and reveals a novel mechanism for hydrocephalus formation

Motility of unicellular organisms occurred early in evolution with the emergence of cilia and flagella. In vertebrates, motile cilia are required for numerous functions such as clearance of the airways and determination of left-right body asymmetry. Ependymal cells lining the brain ventricles also carry motile cilia, but their biological function has remained obscure. Here, we show that ependymal cilia generate a laminar flow of cerebrospinal fluid through the cerebral aqueduct, which we term as 'ependymal flow'. The axonemal dynein heavy chain gene Mdnah5 is specifically expressed in ependymal cells, and is essential for ultrastructural and functional integrity of ependymal cilia. In Mdnah5-mutant mice, lack of ependymal flow causes closure of the aqueduct and subsequent formation of triventricular hydrocephalus during early postnatal brain development. The higher incidence of aqueduct stenosis and hydrocephalus formation in patients with ciliary defects proves the relevance of this novel mechanism in humans.     

Alteration of the LRP1B gene region is associated with high grade of urothelial cancer

We have delineated regions of interest at chromosome 2q21.2, 2q36.3, and 2q37.1 by deletion mapping of 114 urothelial cancers (UC). Altogether, 17%, 18%, and 63% of the G1, G2, and G3 tumors displayed loss of heterozygosity at chromosome 2q, respectively, The region at 2q21.2 was narrowed down to the LRP1B gene (NT_005129.6). Hemi- and homozygous deletion at the LRP1B gene region was seen in 31 of 114 UCs. Only 8% of the UCs with G1 and none with G2 tumors showed loss of heterozygosity at the LRP1B gene, whereas 49% of the G3 UCs had allelic loss at this region. RT-PCR analysis of the LRP1B gene showed the lack of expression of several exons in 2 of 9 cases analyzed. Our analysis suggests that the LRP1B gene is a candidate tumor suppressor gene in UCs.