Population dynamics and genetic connectivity in recent chimpanzee history.

Knowledge on the population history of endangered species is critical for conservation, but whole-genome data on chimpanzees (Pan troglodytes) is geographically sparse. Here, we produced the first non-invasive geolocalized catalog of genomic diversity by capturing chromosome 21 from 828 non-invasive samples collected at 48 sampling sites across Africa. The four recognized subspecies show clear genetic differentiation correlating with known barriers, while previously undescribed genetic exchange suggests that these have been permeable on a local scale. We obtained a detailed reconstruction of population stratification and fine-scale patterns of isolation, migration, and connectivity, including a comprehensive picture of admixture with bonobos (Pan paniscus). Unlike humans, chimpanzees did not experience extended episodes of long-distance migrations, which might have limited cultural transmission. Finally, based on local rare variation, we implement a fine-grained geolocalization approach demonstrating improved precision in determining the origin of confiscated chimpanzees.

[Transition in kidney transplantation]. / Transition en transplantation rénale.

Transition from pediatric to adult care in renal transplantation has emerged as a critical step in the life of a young kidney recipient. During this phase, young patients are faced with the physiological and psychological changes associated with adolescence that can lead to non-compliance and potentially graft loss. To date, there is not a unique accepted model of transition, however it has been proved that the presence of a multidisciplinary team including specialists in adolescent management and in the transition from pediatric to adult transplant care is beneficial during this at-risk phase. The goal of this team is to ensure a progressive transition of the patients according to a precise plan and time line.

Physiopathology of necrobiotic xanthogranuloma with monoclonal gammopathy.

RATIONALE: Xanthomatosis associated with monoclonal gammopathy includes hyperlipidaemic xanthoma (HX), normolipidaemic xanthoma (NX) and necrobiotic xanthogranuloma (NXG). All three pathologies are characterized by skin or visceral lesions related to cholesterol accumulation, monoclonal immunoglobulin (MIg) and hypocomplementemia. The pathophysiology underlying NXG remains unknown although the involvement of MIg is suspected. OBJECTIVE: To provide further insights into the pathophysiology of NXG, we evaluated the plasma lipid phenotype, mechanisms involved in cellular cholesterol accumulation and role of MIg in an analysis of blood and plasma markers of inflammation in 16 patients with xanthomatosis [NXG (n = 8) and NX (n = 8)] associated with monoclonal IgG relative to the relevant controls. RESULTS: The lipid profile of patients with NXG was characterized by a low HDL-C phenotype and an abnormal distribution of HDL particles. Sera from patients with NXG induced cholesterol accumulation in human macrophages. This accumulation was due in part to a significant reduction in the HDL capacity to promote cholesterol efflux from macrophages, which was not found in the case of NX. The MIg of NXG and NX patients was tested positively by ELISA to recognize a large spectrum of lipoproteins. High plasma levels of pro-inflammatory cytokines (TNFα and IL-6), soluble cytokine receptors (sIL-6R, sTNFRI and sTNFRII), adhesion molecules (VCAM-1 and ICAM-1) and chemokines (MCP-1, IL-8 and MIP-1α) were observed in both patients with NXG and NX, revealing a specific xanthoma inflammatory signature which was inversely correlated with plasma levels of anti-inflammatory HDL. However, patients with NXG were distinguished by elevated levels of IL-15 and a marked increase in the rate of intermediate CD14++CD16+ monocytes. CONCLUSION: This study revealed that NXG is characterized by impaired macrophage lipid homeostasis associated with a systemic inflammatory profile that may result from the interaction of MIg and lipoproteins.

Impact of ABCC2 polymorphisms on high-dose methotrexate pharmacokinetics in patients with lymphoid malignancy.

Human multidrug resistance-related protein 2 (MRP2, encoded by ABCC2) is involved in the transport of anionic drugs such as methotrexate (MTX). We prospectively investigated the influence of four common ABCC2 genetic variants (rs717620, rs2273697, rs8187694 and rs8187710) on MTX pharmacokinetics parameters. MTX concentrations were monitored in 50 patients with lymphoid malignancy (27 males; mean age: 53±17 years) receiving high-dose MTX (5.13±1.88 g m(-)(2) in a 4-h perfusion). The population pharmacokinetics modelling showed that ABCC2 -24T allele (rs717620) had a combined influence on both MTX elimination and distribution. The MTX clearance and distribution volume were significantly higher in carriers of at least one copy of the -24T allele as compared with noncarriers: 8.6±2.2 vs 6.7± 2.5 l h(-1), P<0.01 and 30.7±7.7 vs 22.1±8.8 l, P<0.001, respectively. Consequently, -24T allele carriers were more prone to reach MTX nontoxic levels, 48 h after administration.

Plakophilin 2A is the dominant isoform in human heart tissue: consequences for the genetic screening of arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart disease in which mutations affecting Plakophilin-2 (PKP2) are the most frequently detected. However, pathogenicity of variants is not always fully determined. PKP2 encodes two isoforms, the longest (PKP2b) includes the alternatively spliced exon 6, which is routinely screened for molecular diagnosis, despite the absence of data on cardiac expression of PKP2 isoforms. OBJECTIVE: To examine the pathogenicity of PKP2 exon 6 mutations by focusing on a missense variant located in this exon. METHODS AND RESULTS: The PKP2 heterozygous p.Arg490Trp variant was identified in two unrelated ARVC probands (absent from 470 controls). In silico analysis suggested that PKP2 exon 6 is an Alu-derived sequence with very low expression level. PKP2a mRNA, which does not include the sequence encoded by exon 6, was the dominant isoform transcribed; at western blot analysis PKP2A was the only clearly detectable isoform in all human heart samples analysed (from six different controls and the proband). Moreover, in the proband's sample, p.Arg490Trp was not associated with aberrant exon 6 splicing or mutant mRNA downregulation. Finally, a heterozygous missense variant (p.Glu2343Lys) in Desmoplakin was identified in this proband and is likely to be the disease-causing mutation. CONCLUSION: PKP2A was shown to be the major isoform expressed in human heart tissue and PKP2B protein was undetectable. The results strongly suggest that p.Arg490Trp and other variants located in PKP2 exon 6 may not be disease causing. Variant splicing also has important consequences for the interpretation of mutation analysis and genetic counselling in ARVC and other hereditary cardiac diseases.

Endoscope drying/storage cabinet: interest and efficacy.

Inadequate drying of endoscope channels is a possible cause of microbial proliferation during storage. This risk could be reduced by any procedure or process used to dry endoscope channels and control storage conditions. The efficacy of a drying and storage cabinet (Hysis Medical) was tested on three different endoscopes: a colonoscope (Olympus); duodenoscope (Fujinon) and an enteroscope (Pentax), all of which had been artificially contaminated with a suspension of Pseudomonas aeruginosa CIP 103467. Changes to the residual internal contamination level of these endoscopes when stored inside or outside the drying cabinet for 12, 24, 48 or 72 h were compared. When stored in the drying and storage cabinet, microbial contamination levels on endoscopes were lower than the number of bacteria initially introduced and could decrease considerably thereafter. For endoscopes stored outside the drying storage cabinet, microbial numbers were stable or even increased. These data demonstrate the advantages of such endoscope drying/storage cabinets that limit the risk of bacterial proliferation in the internal channels of endoscopes during storage, and which ensure that the disinfection level reached at the end of the reprocessing procedure is maintained.

A warm layer in Venus' cryosphere and high-altitude measurements of HF, HCl, H2O and HDO.

Venus has thick clouds of H2SO4 aerosol particles extending from altitudes of 40 to 60 km. The 60-100 km region (the mesosphere) is a transition region between the 4 day retrograde superrotation at the top of the thick clouds and the solar-antisolar circulation in the thermosphere (above 100 km), which has upwelling over the subsolar point and transport to the nightside. The mesosphere has a light haze of variable optical thickness, with CO, SO2, HCl, HF, H2O and HDO as the most important minor gaseous constituents, but the vertical distribution of the haze and molecules is poorly known because previous descent probes began their measurements at or below 60 km. Here we report the detection of an extensive layer of warm air at altitudes 90-120 km on the night side that we interpret as the result of adiabatic heating during air subsidence. Such a strong temperature inversion was not expected, because the night side of Venus was otherwise so cold that it was named the 'cryosphere' above 100 km. We also measured the mesospheric distributions of HF, HCl, H2O and HDO. HCl is less abundant than reported 40 years ago. HDO/H2O is enhanced by a factor of approximately 2.5 with respect to the lower atmosphere, and there is a general depletion of H2O around 80-90 km for which we have no explanation.

[Review: genetics of familial dilated cardiomyopathy]. / Mise au point sur la génétique de la cardiomyopathie dilatée familiale.

Dilated cardiomyopathy is the most frequent cardiomyopathy. Twenty to 35% of dilated cardiomyopathies are familial. The transmission of the disease is most frequently dominant autosomic. Dilated cardiomyopathy is genetically heterogeneous. Hence, mutations have been identified on 14 genes, and 9 loci have been associated to familial dilated cardiomyopathy. The incriminated mechanisms in the pathogeny of dilated cardiomyopathy include mutations on proteins of the sarcomere, the cytosqueletton, the nuclear membrane or involved in calcium signaling. This review indicates the genes and proteins implicated in the pathogeny of familial dilated cardiomyopathy, and their potential clinical effects.

Danon's disease as a cause of hypertrophic cardiomyopathy: a systematic survey.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease caused by mutations in sarcomeric genes. However, extensive genetic screening failed to identify a mutation in about a third of cases. One possible explanation is that other diseases, caused by other genes, may mimic HCM. OBJECTIVE: To investigate the possible involvement of Danon's disease, an X linked lysosomal disease, in a large population of patients with HCM. METHODS: A population of 197 index cases was considered; 124 were subsequently excluded because of a mutation in sarcomeric genes and 23 because of autosomal dominant inheritance. Fifty index cases were therefore included in molecular analysis (direct sequencing) of the lysosome associated membrane protein 2 (LAMP2) gene responsible for Danon's disease. RESULTS: Two new mutations leading to premature stop codons were identified in patients who evolved towards severe heart failure (< 25 years old): 657C>T and 173_179del. The prevalence was therefore 1% of the total population (two of 197) or 4% of enrolled index cases (two of 50). Interestingly, Danon's disease was responsible for half of the cases (two of four) with HCM and clinical skeletal myopathy but was not involved in isolated HCM (none of 41). CONCLUSIONS: Danon's disease may be involved in patients with previously diagnosed as HCM. A diagnosis strategy is proposed. To distinguish HCM from Danon's disease is important because the clinical evolution, prognosis, mode of inheritance, and therefore genetic counselling are very different.

[Genetics and dilated cardiomyopathy]. / Génétique et cardiomyopathie dilatée.

Dilated cardiomyopathy is characterised by dilatation associated with ventricular dysfunction and represents the leading cause of cardiac transplantation. The aetiology of dilated cardiomyopathy is either multifactorial (about 70% of cases) with genetic and environmental components or monogenic (about 30% of cases) by autosomal dominant transmission. One of the features of this cardiomyopathy is its very wide range of genetic abnormalities and of its phenotype expression. In the multifactorial forms, several polymorphisms have been associated with the predisposition or with the severity of the phenotype. However, these associations have only been observed in a small number of cases and require further confirmation. In the monogenic forms, many culprit genes and morbid loci have been identified. These genes code essentially the proteins involved in the architecture of the cardiomyocyte suggesting mechanisms of action which still remain largely hypothetical. To improve the management of patients and their relatives, other morbid genes remain to be identified in addition to understanding the precise molecular and physiological mechanisms which trigger the disease.

Expanding the phenotype of LMNA mutations in dilated cardiomyopathy and functional consequences of these mutations.

AIMS: Mutations in the lamin A/C gene (LMNA) have been reported to be involved in dilated cardiomyopathy (DCM) associated with conduction system disease and/or skeletal myopathy. The aim of this study was to perform a mutational analysis of LMNA in a large white population of patients affected by dilated cardiomyopathy with or without associated symptoms. METHODS: We performed screening of the coding sequence of LMNA on DNA samples from 66 index cases, and carried out cell transfection experiments to examine the functional consequences of the mutations identified. RESULTS: A new missense (E161K) mutation was identified in a family with early atrial fibrillation and a previously described (R377H) mutation in another family with a quadriceps myopathy associated with DCM. A new mutation (28insA) leading to a premature stop codon was identified in a family affected by DCM with conduction defects. No mutation in LMNA was found in cases with isolated dilated cardiomyopathy. Functional analyses have identified potential physiopathological mechanisms involving identified mutations, such as haploinsufficiency (28insA) or intermediate filament disorganisation (E161K, R377H). CONCLUSION: For the first time, a specific phenotype characterised by early atrial fibrillation is associated with LMNA mutation. Conversely, mutations in LMNA appear as a rare cause of isolated dilated cardiomyopathy. The variable phenotypes observed in LMNA-DCM might be explained by the variability of functional consequences of LMNA mutations.

Induction of angiotensin I-converting enzyme transcription by a protein kinase C-dependent mechanism in human endothelial cells.

Angiotensin I-converting enzyme (ACE) has been implicated in various cardiovascular diseases; however, little is known about the ACE gene regulation in endothelial cells. We have investigated the effect of the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) on ACE activity and gene expression in human umbilical vein endothelial cells (HUVEC). Our results showed a 3- and 5-fold increase in ACE activity in the medium and in the cells, respectively, after 24-h stimulation by PMA. We also observed an increase in the cellular ACE mRNA content starting after 6 h and reaching a 10-fold increase at 24 h in response to 100 ng/ml PMA as measured by ribonuclease protection assay. This effect was mediated by an increased transcription of the ACE gene as demonstrated by nuclear run-on experiments and nearly abolished by the specific PKC inhibitor GF 109203X. Our results indicate that PMA-activated PKC strongly increases ACE mRNA level and ACE gene transcription in HUVEC, an effect associated with an increased ACE secretion. A role for early growth response factor-1 (Egr-1) as a factor regulating ACE gene expression is suggested by both the presence of an Egr-1-responsive element in the proximal portion of the ACE promoter and the kinetics of the Egr-1 mRNA increase in HUVEC treated with PMA.

Angiotensin I-converting enzyme genotype influences arterial response to injury in normotensive rats.

Two normotensive strains of rat, the Lou and Brown Norway (BN) strains, have contrasting levels of plasma angiotensin-converting enzyme (ACE). To investigate the degree of genetic determination of ACE expression, a polymorphic marker of the ACE gene was analyzed in inbred rats of the two strains. The two inbred strains were shown to bear different alleles for a polymorphic marker at the ACE gene. The segregation of the alleles of this marker and the plasma ACE levels were studied in a group of F2 rats issued from a cross between Lou and BN rats. The degree of genetic determination of plasma ACE activity was estimated to be 94% in the F2 cohort. The ACE locus accounts for 74% of total plasma ACE variance. ACE activity and mRNA expression in lungs were also genetically determined. The difference observed in ACE mRNA accumulation in the lungs between the two strains was due to a difference in the transcriptional rate of the ACE gene, as shown in nuclear run-on experiments. No differences were observed in arterial blood pressure of homozygous F2 progeny. In these animals, ACE genotype did not interfere with the pressor or the depressor responses to ACE-dependent vasoactive peptides. There was a significant effect of strain on constitutive or inducible membrane or soluble ACE activity in primary cultures of vascular cells. Neointima formation in the carotid artery 14 days after balloon injury was also influenced by the genotype in F2 homozygous progeny, whereas the medial area was not. These results demonstrate that there is a close relationship between the genetically determined ACE expression and the inducibility of the ACE gene. The degree of genetic determination of ACE expression in inbred rat strains offers a unique opportunity to study the interaction between genetic and environmental determinants of ACE expression and its involvement in response to experimental cardiovascular and renal injury.

Identification of new polymorphisms of the angiotensin I-converting enzyme (ACE) gene, and study of their relationship to plasma ACE levels by two-QTL segregation-linkage analysis.

Plasma angiotensin I-converting enzyme (ACE) levels are highly genetically determined. A previous segregation-linkage analysis suggested the existence of a functional mutation located within or close to the ACE locus, in almost complete linkage desequilibrium (LD) with the ACE insertion/deletion (I/D) polymorphism and accounting for half the ACE variance. In order to identify the functional variant at the molecular level, we compared ACE gene sequences between four subjects selected for having contrasted ACE levels and I/D genotypes. We identified 10 new polymorphisms, among which 8 were genotyped in 95 healthy nuclear families, in addition to the I/D polymorphism. These polymorphisms could be divided into two groups: five polymorphisms in the 5' region and three in the coding sequence and the 3' UTR. Within each group, polymorphisms were in nearly complete association, whereas polymorphisms from the two groups were in strong negative LD. After adjustment for the I/D polymorphism, all polymorphisms of the 5' group remained significantly associated with ACE levels, which suggests the existence of two quantitative trait loci (QTL) acting additively on ACE levels. Segregation-linkage analyses including one or two ACE-linked QTLs in LD with two ACE markers were performed to test this hypothesis. The two QTLs and the two markers were assumed to be in complete LD. Results supported the existence of two ACE-linked QTLs, which would explain 38% and 49% of the ACE variance in parents and offspring, respectively. One of these QTLs might be the I/D polymorphism itself or the newly characterized 4656(CT)2/3 polymorphism. The second QTL would have a frequency of approximately .20, which is incompatible with any of the yet-identified polymorphisms. More extensive sequencing and extended analyses in larger samples and in other populations will be necessary to characterize definitely the functional variants.

A genetic study of angiotensin I-converting enzyme levels in human semen.

The plasma level of angiotensin I-converting enzyme (ACE) has been shown to be under genetic control. An insertion/deletion polymorphism in the ACE gene is associated with differences in the level of ACE in the plasma and inside T-lymphocytes. An ACE isoform is present in large amounts in spermatozoa and is expressed under an alternative, germ cell-specific promoter, whereas ACE present in the seminal fluid is the somatic form of ACE. We have investigated the effect associated with the I/D polymorphism on the level of ACE in seminal fluid and in spermatozoa. No differences in the level of ACE measured in the seminal fluid or in the spermatozoa were associated with the ACE I/D genotypes. We conclude that the modulation of expression associated with the I/D polymorphism is restricted to the somatic ACE promoter. These results also suggest that if one allele modulating the expression of ACE was under positive selection pressure, it was not through an effect on the semen concentration of ACE.

A mutant renin gene in familial elevation of prorenin.

A case of familial elevation of plasma prorenin levels was discovered during an epidemiological survey of a Dutch population. Trypsin-activated prorenin was elevated in the 58-year-old father, his son, and one of his sisters. All family members were normotensive and had normal plasma renin activities. Exon sequencing of the renin gene of the proband and of his son after polymerase chain reaction amplification identified a point mutation in the last exon of the gene (exon 10). A cytosine to thymine transition creates a premature stop codon at position 387 resulting in a truncated form of renin with 20 amino acids deleted from the carboxyl terminus. All family members presenting high levels of plasma prorenin were heterozygous for the mutation. Expression vectors carrying normal or mutated renin cDNA were transiently transfected into AtT-20 cells to test in vitro the functional consequences of this mutation. Measurements of renin activity and pulse-chase experiments indicated that the truncated renin is inactive and not secreted from transfected cells. We hypothesize that the abnormal gene product of the mutated allele alters renin sorting and propose that plasma prorenin elevation may result from a compensatory mechanism.

Expression of PC2 and PC1/PC3 in human pheochromocytomas.

Expressions of two Kex2-related proteases, Pc2 and PC1/PC3, and of one of their possible substrates, proenkephalin, were examined in normal (n = 7) and various pathological (n = 48) human adrenal tissues. Northern blot analysis detected the expression of these genes in pheochromocytomas only. In the 20 pheochromocytomas studied with this technique, PC2, PC1/PC3 and proenkephalin were expressed in 85%, 50% and 90%, respectively. The presence of PC2 and PC1/PC3 was further confirmed using the sensitive RT/PCR techniques. Other evidence of human tumoral adrenal medullary PC2 expression was provided by in situ hybridization and immunohistochemistry. In addition, proenkephalin was expressed only in the pheochromocytomas expressing PC2 and/or PC1/PC3. These results demonstrate that functional Kex2-related endoproteases are expressed in human pheochromocytomas and may be involved in the processing of proenkephalin.

Co-expression of PC2 and proenkephalin in human tumoral adrenal medullary tissues.

Expression of PC2, a Kex2-related protease, and of one of its possible substrates, proenkephalin, was examined in normal adrenal glands (n = 7) and pheochromocytomas (n = 20). PC2 could only be detected in normal adrenal glands using the sensitive RT/PCR technique. By Northern blot, PC2 and proenkephalin were expressed in 85% and 90% of the 20 pheochromocytomas studied, respectively. Moreover, in situ hybridization and immunohistochemistry confirmed expression of PC2 in human tumoral adrenal medullary tissue. These results show for the first time expression of PC2 in human pheochromocytomas which may be involved in the processing of proenkephalin.