Brachial or wrist blood pressure in obese patients: which is the best?

OBJECTIVE: Blood pressure (BP) measured in obese patients with a large arm circumference using a cuff of standard width may be overestimated. METHODS: We compared in this study the BP readings obtained with oscillometric devices at the left arm (OMRON HEM 705-CP) and the left wrist (OMRON R6) (Omron Medizintechnik, Mannheim, Germany) in lean (n=15) and obese (n=11) patients. RESULTS: No difference was found in diastolic BP between the two groups, nor between the arm and the wrist. Systolic BP measured at the arm was, however, significantly lower in obese (99+/-9 mmHg, mean+/-SD) than in lean (107+/-14 mmHg; P<0.001) patients, whereas systolic BP determined at the wrist averaged 106 mmHg in both groups. CONCLUSION: The use of validated wrist BP measuring devices appears therefore particularly appealing in obese individuals with a large arm circumference

Phylogeographic patterning of mtDNA in the widely distributed harvest mouse (Micromys minutus) suggests dramatic cycles of range contraction and expansion during the mid- to late Pleistocene

We examined sequence variation in the mitochondrial cytochrome b gene (1140 bp, n = 73) and control region (842-851 bp, n = 74) in the Eurasian harvest mouse (Micromys minutus (Pallas, 1771)), with samples drawn from across its range, from Western Europe to Japan. Phylogeographic analyses revealed region-specific haplotype groupings combined with overall low levels of inter-regional genetic divergence. Despite the enormous intervening distance, European and East Asian samples showed a net nucleotide divergence of only 0.36%. Based on an evolutionary rate for the cytochrome b gene of 2.4%(.)(site(.)lineage(.)million years)(-1), the initial divergence time of these populations is estimated at around 80 000 years before present. Our findings are consistent with available fossil evidence that has recorded repeated cycles of extinction and recolonization of Europe by M. minutus through the Quaternary. The molecular data further suggest that recolonization occurred from refugia in the Central to East Asian region. Japanese haplotypes of M. minutus, with the exception of those from Tsushima Is., show limited nucleotide diversity (0.15%) compared with those found on the adjacent Korean Peninsula. This finding suggests recent colonization of the Japanese Archipelago, probably around the last glacial period, followed by rapid population growth.

Genomic roles of the HCF transcriptional regulator in "Drosophila"

Abstract : Transcriptional regulation is the result of a combination of positive and negative effectors, such as transcription factors, cofactors and chromatin modifiers. During my thesis project I studied chromatin association, and transcriptional and cell cycle regulatory functions of dHCF, the Drosophila homologue of the human protein HCF-1 (host cell factor-1). The human and Drosophila HCF proteins are synthesized as large polypeptides that are cleaved into two subunits (HCFN and HCFC), which remain associated with one another by non covalent interactions. Studies in mammalian cells over the past 20 years have been devoted to understanding the cellular functions of HCF-1 and have revealed that it is a key regulator of transcription and cell cycle regulation. In human cells, HCF-1 interacts with the histone methyltransferase Set1/Ash2 and MLL/Ash2 complexes and the histone deacetylase Sin3 complex, which are involved in transcriptional activation and repression, respectively. HCF-1 is also recruited to promoters to regulate G1 -to-S phase progression during the cell cycle by the activator transcription factors E2F1 and E2F3, and by the repressor transcription factor E2F4. HCF-1 protein structure and these interactions between HCP-1 and E2F transcriptional regulator proteins are also conserved in Drosophila. In this doctoral thesis, I use proliferating Drosophila SL2 cells to study both the genomic-binding sites of dHCF, using a combination of chromatin immunoprecipitation and ultra high throughput sequencing (ChIP-seq) analysis, and dHCF regulated genes, employing RNAi and microarray expression analysis. I show that dHCF is bound to over 7500 chromosomal sites in proliferating SL2 cells, and is located at +-200 bp relative to the transcriptional start sites of about 30% of Drosophila genes. There is also a direct relationship between dHCF promoter association and promoter- associated transcriptional activity. Thus, dHCF binding levels at promoters correlated directly with transcriptional activity. In contrast, expression studies showed that dHCF appears to be involved in both transcriptional activation and repression. Analysis of dHCF-binding sites identified nine dHCF-associated motifs, four of them linked dHCF to (i) two insulator proteins, GAGA and BEAF, (ii) the E-box motif, and (iii) a degenerated TATA-box. The dHCF-associated motifs allowed the organization of the dHCF-bound genes into five biological processes: differentiation, cell cycle and gene expression, regulation of endocytosis, and cellular localization. I further show that different mechanisms regulate dHCF association with chromatin. Despite that after dHCF cleavage the dHCFN and dHCFC subunits remain associated, the two subunits showed different affinities for chromatin and differential binding to a set of tested promoters, suggesting that dHCF could target specific promoters through each of the two subunits. Moreover, in addition to the interaction between dHCF and E2F transcription factors, the dHCF binding pattern is correlated with dE2F2 genomic 4 distribution. I show that dE2F factors are necessary for recruitment of dHCF to the promoter of a set of dHCF regulated genes. Therefore dHCF, as in mammals, is involved in regulation of G1 to S phase progression in collaboration with the dE2Fs transcription factors. In addition, gene expression arrays reveal that dHCF could indirectly regulate cell cycle progression by promoting expression of genes involved in gene expression and protein synthesis, and inhibiting expression of genes involved in cell-cell adhesion. Therefore, dHCF is an evolutionary conserved protein, which binds to many specific sites of the Drosophila genome via interaction with DNA of chromatin-binding proteins to regulate the expression of genes involved in many different cellular functions. Résumé : La regulation de la transcription est le résultat des effets positifs et négatifs des facteurs de transcription, cofacteurs et protéines effectrices qui modifient la chromatine. Pendant mon projet de thèse, j'ai étudié l'association a la chromatine, ainsi que la régulation de la transcription et du cycle cellulaire par dHCF, l'homologue chez la drosophile de la protéine humaine HCF-1 (host cell factor-1). Chez 1'humain et la V drosophile, les deux protéines HCF sont synthétisées sous la forme d'un long polypeptide, qui est ensuite coupé en deux sous-unités au centre de la protéine. Les deux sous-unités restent associées ensemble grâce a des interactions non-covalentes. Des études réalisées pendant les 20 dernières années ont permit d'établir que HCF-l et un facteur clé dans la régulation de la transcription et du cycle cellulaire. Dans les cellules humaines, HCF-1 active et réprime la transcription en interagissant avec des complexes de protéines qui activent la transcription en méthylant les histones (HMT), comme par Set1/Ash2 et MLL/Ash2, et d'autres complexes qui répriment la transcription et sont responsables de la déacétylation des histones (HDAC) comme la protéine Sin3. HCF-l est aussi recruté aux promoteurs par les activateurs de la transcription E2F l et E2F3a, et par le répresseur de la transcription E2F4 pour réguler la transition entre les phases G1 et S du cycle cellulaire. La structure de HCF-1 et les interactions entre HCF-l et les régulateurs de la transcription sont conservées chez la drosophile. Pendant ma these j'ai utilisé les cellules de la drosophile, SL2 en culture, pour étudier les endroits de liaisons de HCF-l à la chromatine, grâce a immunoprecipitation de la chromatine et du séquençage de l'ADN massif ainsi que les gènes régulés par dHCF 3 grâce a la technique de RNAi et des microarrays. Mes résultats on montré que dHCF se lie à environ 7565 endroits, et estimé a 1200 paire de bases autour des sites d'initiation de la transcription de 30% des gènes de la drosophile. J 'ai observe une relation entre dHCF et le niveau de la transcription. En effet, le niveau de liaison dHCF au promoteur corrèle avec l'activité de la transcription. Cependant, mes études d'expression ont montré que dHCF est implique dans le processus d'activation et mais aussi de répression de la transcription. L'analyse des séquences d'ADN liées par dHCF a révèle neuf motifs, quatre de ces motifs ont permis d'associer dl-ICF a deux protéines isolatrices GAGA et BEAF, au motif pour les E-boxes et a une TATA-box dégénérée. Les neuf motifs associes à dHCF ont permis d'associer les gènes lies par dHCF au promoteur a cinq processus biologiques: différentiation, cycle cellulaire, expression de gènes, régulation de l'endocytosis et la localisation cellulaire, J 'ai aussi montré qu'il y a plusieurs mécanismes qui régulent l'association de dHCF a la chromatine, malgré qu'après clivage, les deux sous-unites dHCFN and dHCFC, restent associées, elles montrent différentes affinités pour la chromatine et lient différemment un group de promoteurs, les résultats suggèrent que dHCF peut se lier aux promoteurs en utilisant chacune de ses sous-unitées. En plus de l'association de dHCF avec les facteurs de transcription dE2F s, la distribution de dHCF sur le génome corrèle avec celle du facteur de transcription dE2F2. J'ai aussi montré que les dE2Fs sont nécessaires pour le recrutement de dHCF aux promoteurs d'un sous-groupe de gènes régules par dHCF. Mes résultats ont aussi montré que chez la drosophile comme chez les humains, dl-ICF est implique dans la régulation de la progression de la phase G1 a la phase S du cycle cellulaire en collaboration avec dE2Fs. D'ailleurs, les arrays d'expression ont suggéré que dHCF pourrait réguler le cycle cellulaire de façon indirecte en activant l'expression de gènes impliqués dans l'expression génique et la synthèse de protéines, et en inhibant l'expression de gènes impliqués dans l'adhésion cellulaire. En conclusion, dHCF est une protéine, conservée dans l'évolution, qui se lie spécifiquement a beaucoup d'endroits du génome de Drosophile, grâce à l'interaction avec d'autres protéines, pour réguler l'expression des gènes impliqués dans plusieurs fonctions cellulaires.

Functional interaction between the estrogen receptor and CTF1: analysis of the vitellogenin gene B1 promoter in yeast.

Eukaryotic gene expression depends on a complex interplay between the transcriptional apparatus and chromatin structure. We report here a yeast model system for investigating the functional interaction between the human estrogen receptor (hER) and CTF1, a member of the CTF/NFI transcription factor family. We show that a CTF1-fusion protein and the hER transactivate a synthetic promoter in yeast in a synergistic manner. This interaction requires the proline-rich transactivation domain of CTF1. When the natural estrogen-dependent vitellogenin B1 promoter is tested in yeast, CTF1 and CTF1-fusion proteins are unable to activate transcription, and no synergy is observed between hER, which activates the B1 promoter, and these factors. Chromatin structure analysis on this promoter reveals positioned nucleosomes at -430 to -270 (+/-20 bp) and at -270 to - 100 (+/-20 bp) relative to the start site of transcription. The positions of the nucleosomes remain unchanged upon hormone-dependent transcriptional activation of the promoter, and the more proximal nucleosome appears to mask the CTF/NFI site located at - 101 to -114. We conclude that a functional interaction of hER with the estrogen response element located upstream of a basal promoter occurs in yeast despite the nucleosomal organization of this promoter, whereas the interaction of CTF1 with its target site is apparently precluded by a nucleosome.

Incidence of bullous pemphigoid and pemphigus in Switzerland: a 2-year prospective study.

BACKGROUND: Bullous pemphigoid (BP), pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are autoimmune bullous diseases characterized by the presence of tissue-bound and circulating autoantibodies directed against disease-specific target antigens of the skin. Although rare, these diseases run a chronic course and are associated with significant morbidity and mortality. There are few prospective data on gender- and age-specific incidence of these disorders. OBJECTIVES: Our aims were: (i) to evaluate the incidence of BP and PV/PF in Swiss patients, as the primary endpoint; and (ii) to assess the profile of the patients, particularly for comorbidities and medications, as the secondary endpoint. METHODS: The protocol of the study was distributed to all dermatology clinics, immunopathology laboratories and practising dermatologists in Switzerland. All newly diagnosed cases of BP and pemphigus occurring between 1 January 2001 and 31 December 2002 were collected. In total, 168 patients (73 men and 95 women) with these autoimmune bullous diseases, with a diagnosis based on clinical, histological and immunopathological criteria, were finally included. RESULTS: BP showed a mean incidence of 12.1 new cases per million people per year. Its incidence increased significantly after the age of 70 years, with a maximal value after the age of 90 years. The female/male ratio was 1.3. The age-standardized incidence of BP using the European population as reference was, however, lower, with 6.8 new cases per million people per year, reflecting the ageing of the Swiss population. In contrast, both PV and PF were less frequent. Their combined mean incidence was 0.6 new cases per million people per year. CONCLUSIONS; This is the first comprehensive prospective study analysing the incidence of autoimmune bullous diseases in an entire country. Our patient cohort is large enough to establish BP as the most frequent autoimmune bullous disease. Its incidence rate appears higher compared with other previous studies, most likely because of the demographic characteristics of the Swiss population. Nevertheless, based on its potentially misleading presentations, it is possible that the real incidence rate of BP is still underestimated. Based on its significant incidence in the elderly population, BP should deserve more public health concern.

Stratigraphie, morphodynamique, paléoenvironnements des terrains sédimentaires meubles à forte déclivité du domaine périglaciaire alpin

Dans le contexte d'un climat de plus en plus chaud, une étude « géosystémique » de la répartition du pergélisol dans l'ensemble d'un versant périglaciaire alpin, de la paroi rocheuse jusqu'au glacier rocheux, s'avère primordiale. S'insérant dans cette problématique, ce travail de thèse vise comme objectif général l'étude des versants d'éboulis situés à l'intérieur de la ceinture du pergélisol discontinu selon deux volets de recherche différents : une étude de la stratigraphie et de la répartition du pergélisol dans les éboulis de haute altitude et des processus qui lui sont associés ; une reconstitution de l'histoire paléoenvironnementale du domaine périglaciaire alpin pendant le Tardiglaciaire et l'Holocène. La stratigraphie et la répartition spatiale du pergélisol a été étudiée dans cinq éboulis des Alpes Valaisannes (Suisse), dont trois ont fait l'objet de forages profonds, grâce à la prospection géophysique de détail effectuée à l'aide de méthodes thermiques, de résistivité, sismiques et nucléaires. Les mesures effectuées ont permis de mettre en évidence que, dans les cinq éboulis étudiés, la répartition du pergélisol est discontinue et aucun des versants n'est intégralement occupé par du pergélisol. En particulier, il a été possible de prouver de manière directe que, dans un éboulis, le pergélisol est présent dans les parties inférieures du versant et absent dans les parties supérieures. Trois facteurs de contrôle principaux de la répartition du pergélisol déterminée au sein des éboulis étudiés ont été individualisés, pouvant agir seuls ou de manière combinée : la ventilation ascendante, l'augmentation de la granulométrie en direction de l'aval et la redistribution de la neige par le vent et les avalanches. Parmi ceux-ci, la relation ventilation - granulométrie semble être le facteur de contrôle principal permettant d'expliquer la présence de pergélisol dans les parties inférieures d'un éboulis et son absence dans les parties supérieures. Enfin, l'analyse de la structure des éboulis périglaciaires de haute altitude a permis de montrer que la stratigraphie du pergélisol peut être un élément important pour l'interprétation de la signification paléoclimatique de ce type de formes. Pour le deuxième volet de la recherche, grâce aux datations relatives effectuées à l'aide de l'utilisation conjointe de la méthode paléogéographique et du marteau de Schmidt, il a été possible de définir la chrono - stratigraphie du retrait glaciaire et du développement des glaciers rocheux et des versants d'éboulis d es quatre régions des Alpes suisses étudiées (régions du Mont Gelé - Mont Fort, des Fontanesses et de Chamosentse , dans les Alpes Valaisannes, et Massif de la Cima di Gana Bianca , dans les Alpes Tessinoises). La compilation de toutes les datations effectuées a permis de montrer que la plupart des glaciers rocheux actifs étudiés se seraient développés soit juste avant et/ou pendant l'Optimum Climatique Holocène de 9.5 - 6.3 ka cal BP, soit au plus tard juste après cet évènement climatique majeur du dernier interglaciaire. Parmi les glaciers rocheux fossiles datés, la plupart aurait commencé à se former dans la deuxième moitié du Tardiglaciaire et se serait inactivé dans la première partie de l'Optimum Climatique Holocène. Pour les éboulis étudiés, les datations effectuées ont permis d'observer que leur surface date de la période entre le Boréal et l'Atlantique récent, indiquant que les taux d'éboulisation après la fin de l'Optimum Climatique Holocène ont dû être faibles, et que l'intervalle entre l'âge maximal et l'âge minimal est dans la plupart des cas relativement court (4 - 6 millénaires), indiquant que les taux d'éboulisation durant la période de formation des éboulis ont dû être importants. Grâce au calcul des taux d'érosion des parois rocheuses sur la base du volume de matériaux rocheux pour quatre des éboulis étudiés, il a été possible mettre en évidence l'existence d'une « éboulisation parapériglaciaire » liée à la dégradation du pergélisol dans les parois rocheuses, fonctionnant principalement durant les périodes de réchauffement climatique rapide comme cela a été le cas au début du Bølling, du Préboréal à la fin de l'Atlantique récent et, peut-être, à partir des années 1980.

3D reconstruction and comparison of shapes of DNA minicircles observed by cryo-electron microscopy.

We use cryo-electron microscopy to compare 3D shapes of 158 bp long DNA minicircles that differ only in the sequence within an 18 bp block containing either a TATA box or a catabolite activator protein binding site. We present a sorting algorithm that correlates the reconstructed shapes and groups them into distinct categories. We conclude that the presence of the TATA box sequence, which is believed to be easily bent, does not significantly affect the observed shapes.

Homeodomain binding motifs modulate the probability of odorant receptor gene choice in transgenic mice.

Odorant receptor (OR) genes constitute with 1200 members the largest gene family in the mouse genome. A mature olfactory sensory neuron (OSN) is thought to express just one OR gene, and from one allele. The cell bodies of OSNs that express a given OR gene display a mosaic pattern within a particular region of the main olfactory epithelium. The mechanisms and cis-acting DNA elements that regulate the expression of one OR gene per OSN - OR gene choice - remain poorly understood. Here, we describe a reporter assay to identify minimal promoters for OR genes in transgenic mice, which are produced by the conventional method of pronuclear injection of DNA. The promoter transgenes are devoid of an OR coding sequence, and instead drive expression of the axonal marker tau-β-galactosidase. For four mouse OR genes (M71, M72, MOR23, and P3) and one human OR gene (hM72), a mosaic, OSN-specific pattern of reporter expression can be obtained in transgenic mice with contiguous DNA segments of only ~300 bp that are centered around the transcription start site (TSS). The ~150bp region upstream of the TSS contains three conserved sequence motifs, including homeodomain (HD) binding sites. Such HD binding sites are also present in the H and P elements, DNA sequences that are known to strongly influence OR gene expression. When a 19mer encompassing a HD binding site from the P element is multimerized nine times and added upstream of a MOR23 minigene that contains the MOR23 coding region, we observe a dramatic increase in the number of transgene-expressing founders and lines and in the number of labeled OSNs. By contrast, a nine times multimerized 19mer with a mutant HD binding site does not have these effects. We hypothesize that HD binding sites in the H and P elements and in OR promoters modulate the probability of OR gene choice.

Blood pressure and LDL-cholesterol targets for prevention of recurrent strokes and cognitive decline in the hypertensive patient: design of the European Society of Hypertension-Chinese Hypertension League Stroke in Hypertension Optimal Treatment randomized trial.

BACKGROUND AND OBJECTIVES: The SBP values to be achieved by antihypertensive therapy in order to maximize reduction of cardiovascular outcomes are unknown; neither is it clear whether in patients with a previous cardiovascular event, the optimal values are lower than in the low-to-moderate risk hypertensive patients, or a more cautious blood pressure (BP) reduction should be obtained. Because of the uncertainty whether 'the lower the better' or the 'J-curve' hypothesis is correct, the European Society of Hypertension and the Chinese Hypertension League have promoted a randomized trial comparing antihypertensive treatment strategies aiming at three different SBP targets in hypertensive patients with a recent stroke or transient ischaemic attack. As the optimal level of low-density lipoprotein cholesterol (LDL-C) level is also unknown in these patients, LDL-C-lowering has been included in the design. PROTOCOL DESIGN: The European Society of Hypertension-Chinese Hypertension League Stroke in Hypertension Optimal Treatment trial is a prospective multinational, randomized trial with a 3 × 2 factorial design comparing: three different SBP targets (1, <145-135; 2, <135-125; 3, <125 mmHg); two different LDL-C targets (target A, 2.8-1.8; target B, <1.8 mmol/l). The trial is to be conducted on 7500 patients aged at least 65 years (2500 in Europe, 5000 in China) with hypertension and a stroke or transient ischaemic attack 1-6 months before randomization. Antihypertensive and statin treatments will be initiated or modified using suitable registered agents chosen by the investigators, in order to maintain patients within the randomized SBP and LDL-C windows. All patients will be followed up every 3 months for BP and every 6 months for LDL-C. Ambulatory BP will be measured yearly. OUTCOMES: Primary outcome is time to stroke (fatal and non-fatal). Important secondary outcomes are: time to first major cardiovascular event; cognitive decline (Montreal Cognitive Assessment) and dementia. All major outcomes will be adjudicated by committees blind to randomized allocation. A Data and Safety Monitoring Board has open access to data and can recommend trial interruption for safety. SAMPLE SIZE CALCULATION: It has been calculated that 925 patients would reach the primary outcome after a mean 4-year follow-up, and this should provide at least 80% power to detect a 25% stroke difference between SBP targets and a 20% difference between LDL-C targets.

Impact of different adiposity measures on the relation between serum uric acid and blood pressure in young adults.

Serum uric acid (SUA) concentration is independently associated with blood pressure (BP) in adults. We examined this association in young adults at an age where anti-hypertension treatment, other potential confounding factors and co-morbidity are unlikely to occur. We assessed BP, anthropometric variables including weight, height, waist circumference (WC), body fat percent (using bioimpedance), lifestyle behaviors, SUA and blood lipids in 549 participants aged 19-20 years from a population-based cohort study (Seychelles Child Development Study). Mean (s.d.) SUA was higher in males than females, 0.33 (0.08) and 0.24 (0.07) mmol l(-1), respectively. Body mass index (BMI) was higher in females than males but BP was markedly higher in males than in females. SUA was associated with both systolic and diastolic BP. However, the magnitude of the linear regression coefficients relating BP and SUA decreased by up to 50% upon adjustment for BMI, WC or body fat percent. The association between SUA and BP was not altered upon further adjustment for alcohol intake, smoking, triglycerides or renal function. In fully adjusted models, SUA remained associated with BP (P<0.05) in females. In conclusion, adiposity substantially decreased the association between SUA and BP in young adults, and BP was independently associated with SUA in females. These findings suggest a role of adiposity in the link between hyperuricemia and hypertension.

Cooperative kinking at distant sites in mechanically stressed DNA.

In cells, DNA is routinely subjected to significant levels of bending and twisting. In some cases, such as under physiological levels of supercoiling, DNA can be so highly strained, that it transitions into non-canonical structural conformations that are capable of relieving mechanical stress within the template. DNA minicircles offer a robust model system to study stress-induced DNA structures. Using DNA minicircles on the order of 100 bp in size, we have been able to control the bending and torsional stresses within a looped DNA construct. Through a combination of cryo-EM image reconstructions, Bal31 sensitivity assays and Brownian dynamics simulations, we have been able to analyze the effects of biologically relevant underwinding-induced kinks in DNA on the overall shape of DNA minicircles. Our results indicate that strongly underwound DNA minicircles, which mimic the physical behavior of small regulatory DNA loops, minimize their free energy by undergoing sequential, cooperative kinking at two sites that are located about 180° apart along the periphery of the minicircle. This novel form of structural cooperativity in DNA demonstrates that bending strain can localize hyperflexible kinks within the DNA template, which in turn reduces the energetic cost to tightly loop DNA.

The effect of continuous positive airway pressure on total cerebral blood flow in healthy awake volunteers.

PURPOSE: Continuous positive airway pressure (CPAP) is the gold standard treatment for obstructive sleep apnea. However, the physiologic impact of CPAP on cerebral blood flow (CBF) is not well established. Ultrasound can be used to estimate CBF, but there is no widespread accepted protocol. We studied the physiologic influence of CPAP on CBF using a method integrating arterial diameter and flow velocity (FV) measurements obtained for each vessel supplying blood to the brain. METHODS: FV and lumen diameter of the left and right internal carotid, vertebral, and middle cerebral arteries were measured using duplex Doppler ultrasound with and without CPAP at 15 cm H(2)O, applied in a random order. Transcutaneous carbon dioxide (PtcCO(2)), heart rate (HR), blood pressure (BP), and oxygen saturation were monitored. Results were compared with a theoretical prediction of CBF change based on the effect of partial pressure of carbon dioxide on CBF. RESULTS: Data were obtained from 23 healthy volunteers (mean ± SD; 12 male, age 25.1 ± 2.6 years, body mass index 21.8 ± 2.0 kg/m(2)). The mean experimental and theoretical CBF decrease under CPAP was 12.5 % (p < 0.001) and 11.9 % (p < 0.001), respectively. The difference between experimental and theoretical CBF reduction was not statistically significant (3.84 ± 79 ml/min, p = 0.40). There was a significant reduction in PtcCO(2) with CPAP (p = <0.001) and a significant increase in mean BP (p = 0.0017). No significant change was observed in SaO(2) (p = 0.21) and HR (p = 0.62). CONCLUSION: Duplex Doppler ultrasound measurements of arterial diameter and FV allow for a noninvasive bedside estimation of CBF. CPAP at 15 cm H(2)O significantly decreased CBF in healthy awake volunteers. This effect appeared to be mediated predominately through the hypocapnic vasoconstriction coinciding with PCO(2) level reduction. The results suggest that CPAP should be used cautiously in patients with unstable cerebral hemodynamics.

Is the Gibraltar strait a barrier to gene flow for the bat Myotis myotis (Chiroptera: Vespertilionidae)?

Because of their role in limiting gene flow, geographical barriers like mountains or seas often coincide with intraspecific genetic discontinuities. Although the Strait of Gibraltar represents such a potential barrier for both plants and animals, few studies have been conducted on its impact on gene flow. Here we test this effect on a bat species (Myotis myotis) which is apparently distributed on both sides of the strait. Six colonies of 20 Myotis myotis each were sampled in southern Spain and northern Morocco along a linear transect of 1350 km. Results based on six nuclear microsatellite loci reveal no significant population structure within regions, but a complete isolation between bats sampled on each side of the strait. Variability at 600 bp of a mitochondrial gene (cytochrome b) confirms the existence of two genetically distinct and perfectly segregating clades, which diverged several million years ago. Despite the narrowness of the Gibraltar Strait (14 km), these molecular data suggest that neither males, nor females from either region have ever reproduced on the opposite side of the strait. Comparisons of molecular divergence with bats from a closely related species (M. blythii) suggest that the North African clade is possibly a distinct taxon warranting full species rank. We provisionally refer to it as Myotis cf punicus Felten 1977, but a definitive systematic understanding of the whole Mouse-eared bat species complex awaits further genetic sampling, especially in the Eastern Mediterranean areas.

Detection of live and antibiotic-killed bacteria by quantitative real-time PCR of specific fragments of rRNA.

Assessing bacterial viability by molecular markers might help accelerate the measurement of antibiotic-induced killing. This study investigated whether rRNA could be suitable for this purpose. Cultures of penicillin-susceptible and penicillin-tolerant (Tol1 mutant) Streptococcus gordonii were exposed to mechanistically different penicillin and levofloxacin. Bacterial survival was assessed by viable counts and compared to quantitative real-time PCR amplification of either the 16S rRNA genes or the 16S rRNA, following reverse transcription. Penicillin-susceptible S. gordonii lost > or =4 log(10) CFU/ml of viability over 48 h of penicillin treatment. In comparison, the Tol1 mutant lost < or =1 log(10) CFU/ml. Amplification of a 427-bp fragment of 16S rRNA genes yielded amplicons that increased proportionally to viable counts during bacterial growth but did not decrease during drug-induced killing. In contrast, the same 427-bp fragment amplified from 16S rRNA paralleled both bacterial growth and drug-induced killing. It also differentiated between penicillin-induced killing of the parent and the Tol1 mutant (> or =4 log(10) CFU/ml and < or =1 log(10) CFU/ml, respectively) and detected killing by mechanistically unrelated levofloxacin. Since large fragments of polynucleotides might be degraded faster than smaller fragments, the experiments were repeated by amplifying a 119-bp region internal to the original 427-bp fragment. The amount of 119-bp amplicons increased proportionally to viability during growth but remained stable during drug treatment. Thus, 16S rRNA was a marker of antibiotic-induced killing, but the size of the amplified fragment was critical for differentiation between live and dead bacteria.

Molecular evidence of Pleistocene bidirectional faunal exchange between Europe and the Near East: the case of the bicoloured shrew (Crocidura leucodon, Soricidae).

We sequenced 1077 bp of the mitochondrial cytochrome b gene and 511 bp of the nuclear Apolipoprotein B gene in bicoloured shrew (Crocidura leucodon, Soricidae) populations ranging from France to Georgia. The aims of the study were to identify the main genetic clades within this species and the influence of Pleistocene climatic variations on the respective clades. The mitochondrial analyses revealed a European clade distributed from France eastwards to north-western Turkey and a Near East clade distributed from Georgia to Romania; the two clades separated during the Middle Pleistocene. We clearly identified a population expansion after a bottleneck for the European clade based on mitochondrial and nuclear sequencing data; this expansion was not observed for the eastern clade. We hypothesize that the western population was confined to a small Italo-Balkanic refugium, whereas the eastern population subsisted in several refugia along the southern coast of the Black Sea.