A cryptic heterogametic transition revealed by sex-linked DNA markers in Palearctic green toads.

In sharp contrast to birds and mammals, most cold-blooded vertebrates have homomorphic (morphologically undifferentiated) sex chromosomes. This might result either from recurrent X-Y recombination (occurring e.g. during occasional events of sex reversal) or from frequent turnovers (during which sex-determining genes are overthrown by new autosomal mutations). Evidence for turnovers is indeed mounting in fish, but very few have so far been documented in amphibians, possibly because of practical difficulties in identifying sex chromosomes. Female heterogamety (ZW) has long been established in Bufo bufo, based on sex reversal and crossing experiments. Here, we investigate a sex-linked marker identified from a laboratory cross between Palearctic green toads (Bufo viridis subgroup). The F(1) offspring produced by a female Bufo balearicus and a male Bufo siculus were phenotypically sexed, displaying an even sex ratio. A sex-specific marker detected in highly reproducible AFLP genotypes was cloned. Sequencing revealed a noncoding, microsatellite-containing fragment. Reamplification and genotyping of families of this and a reciprocal cross showed B. siculus to be male heterogametic (XY) and suggested the same system for B. balearicus. Our results thus reveal a cryptic heterogametic transition within bufonid frogs and help explain patterns of hybrid fitness within the B. viridis subgroup. Turnovers of genetic sex-determination systems may be more frequent in amphibians than previously thought and thus contribute to the prevalence of homomorphic sex chromosomes in this group.

Combining bone resorption markers and heel quantitative ultrasound to discriminate between fracture cases and controls.

This nested case-control analysis of a Swiss ambulatory cohort of elderly women assessed the discriminatory power of urinary markers of bone resorption and heel quantitative ultrasound for non-vertebral fractures. The tests all discriminated between cases and controls, but combining the two strategies yielded no additional relevant information. INTRODUCTION: Data are limited regarding the combination of bone resorption markers and heel quantitative bone ultrasound (QUS) in the detection of women at risk for fracture. METHODS: In a nested case-control analysis, we studied 368 women (mean age 76.2 +/- 3.2 years), 195 with low-trauma non-vertebral fractures and 173 without, matched for age, BMI, medical center, and follow-up duration, from a prospective study designed to predict fractures. Urinary total pyridinolines (PYD) and deoxypyridinolines (DPD) were measured by high performance liquid chromatography. All women underwent bone evaluations using Achilles+ and Sahara heel QUS. RESULTS: Areas under the receiver operating-characteristic curve (AUC) for discriminative models of the fracture group, with 95% confidence intervals, were 0.62 (0.56-0.68) and 0.59 (0.53-0.65) for PYD and DPD, and 0.64 (0.58-0.69) and 0.65 (0.59-0.71) for Achilles+ and Sahara QUS, respectively. The combination of resorption markers and QUS added no significant discriminatory information to either measurement alone with an AUC of 0.66 (0.60-0.71) for Achilles+ with PYD and 0.68 (0.62-0.73) for Sahara with PYD. CONCLUSIONS: Urinary bone resorption markers and QUS are equally discriminatory between non-vertebral fracture patients and controls. However, the combination of bone resorption markers and QUS is not better than either test used alone.

Evaluation of the specific IgG- and IgA-antibody response against immundominant Aspergillus fumigatus antigens as diagnostic markers of invasive aspergillosis

An improvement in the serological diagnostic toolbox of invasive aspergillosis (IA) is necessary. So far, most laboratories do not perform antibody detection assays at all to diagnose IA, as commercial test systems are based on crude and undefined antigen mixtures of A. fumigatus. Utilizing the A. fumigatus protein mitogillin, we could demonstrate that the use of selected characterized immunodominant antigens can improve the serodiagnosis of Aspergillus-related diseases. In an animal model we were able to identify additional 36 immunodominant antigens of a cDNA library of A. fumigatus germlings. Five selected antigens were expressed recombinantly in E. coli, purified and used for Westernblot und ELISA analyses to study the kinetics of the specific antibody response in rabbits that were infected systemically with A. fumigatus. Subsequently, the specific IgG- and IgA-antibody responses against these antigens were studied in patients suffering from proven IA and compared to healthy blood donors and patients with other forms of pneumonia. Furthermore, we examined how total IgG- and IgA-levels influence the diagnostic value of antibody detection in IA patients.

Evolutionary history of the greater white-toothed shrew (Crocidura russula) inferred from analysis of mtDNA, Y, and X chromosome markers.

We investigate the evolutionary history of the greater white-toothed shrew across its distribution in northern Africa and mainland Europe using sex-specific (mtDNA and Y chromosome) and biparental (X chromosome) markers. All three loci confirm a large divergence between eastern (Tunisia and Sardinia) and western (Morocco and mainland Europe) lineages, and application of a molecular clock to mtDNA divergence estimates indicates a more ancient separation (2.25 M yr ago) than described by some previous studies, supporting claims for taxonomic revision. Moroccan ancestry for the mainland European population is inconclusive from phylogenetic trees, but is supported by greater nucleotide diversity and a more ancient population expansion in Morocco than in Europe. Signatures of rapid population expansion in mtDNA, combined with low X and Y chromosome diversity, suggest a single colonization of mainland Europe by a small number of Moroccan shrews >38 K yr ago. This study illustrates that multilocus genetic analyses can facilitate the interpretation of species' evolutionary history but that phylogeographic inference using X and Y chromosomes is restricted by low levels of observed polymorphism.

Design, conduct, and analyses of Breast International Group (BIG) 1-98: a randomized, double-blind, phase-III study comparing letrozole and tamoxifen as adjuvant endocrine therapy for postmenopausal women with receptor-positive, early breast cancer.

BACKGROUND: Aromatase inhibitors provide superior disease control when compared with tamoxifen as adjuvant therapy for postmenopausal women with endocrine-responsive early breast cancer. PURPOSE: To present the design, history, and analytic challenges of the Breast International Group (BIG) 1-98 trial: an international, multicenter, randomized, double-blind, phase-III study comparing the aromatase inhibitor letrozole with tamoxifen in this clinical setting. METHODS: From 1998-2003, BIG 1-98 enrolled 8028 women to receive monotherapy with either tamoxifen or letrozole for 5 years, or sequential therapy of 2 years of one agent followed by 3 years of the other. Randomization to one of four treatment groups permitted two complementary analyses to be conducted several years apart. The first, reported in 2005, provided a head-to-head comparison of letrozole versus tamoxifen. Statistical power was increased by an enriched design, which included patients who were assigned sequential treatments until the time of the treatment switch. The second, reported in late 2008, used a conditional landmark approach to test the hypothesis that switching endocrine agents at approximately 2 years from randomization for patients who are disease-free is superior to continuing with the original agent. RESULTS: The 2005 analysis showed the superiority of letrozole compared with tamoxifen. The patients who were assigned tamoxifen alone were unblinded and offered the opportunity to switch to letrozole. Results from other trials increased the clinical relevance about whether or not to start treatment with letrozole or tamoxifen, and analysis plans were expanded to evaluate sequential versus single-agent strategies from randomization. LIMITATIONS: Due to the unblinding of patients assigned tamoxifen alone, analysis of updated data will require ascertainment of the influence of selective crossover from tamoxifen to letrozole. CONCLUSIONS: BIG 1-98 is an example of an enriched design, involving complementary analyses addressing different questions several years apart, and subject to evolving analytic plans influenced by new data that emerge over time.

Characterization of thirteen microsatellite markers in river and brook lampreys (Lampetra fluviatilis and L-planeri)

We describe the development based on 454 pyrosequencing technology of thirteen microsatellite markers for two closely related species of lamprey: Lampetra fluviatilis and L. planeri. The number of alleles per locus ranged from 2 to 5 in L. fluviatilis and from 2 to 6 in L. planeri. Gene diversity ranged from 0.062 to 0.718 in L. fluviatilis and from 0.322 to 0.677 in L. planeri. These markers will be helpful to study population genetic structure of both species and resolve their taxonomic status as separate species or ecotypes of a single species.

Relation between high-sensitivity C-reactive protein and cardiovascular and renal markers in a middle-income country in the African region.

BACKGROUND: High-sensitivity C-reactive protein (hs-CRP) is associated with several cardiovascular risk factors (CVRF) and with renal function markers. However, these associations have not been examined in populations in the African region. We analyzed the distribution of hs-CRP and the relationship with a broad set of CVRF, renal markers and carotid intima-media thickness (IMT), in the Seychelles (African region). METHODS: We conducted a survey in the population aged 25-64years (n=1255, participation rate: 80.2%). Analyses were restricted to persons of predominantly African descent (n=1011). RESULTS: Mean and median hs-CRP serum concentrations (mg/l) were 3.1 (SD 7.6) and 1.4 (IQR 0.7-2.9) in men and 4.5 (SD 6.7) and 2.2 (IQR 1.0-5.4) in women (p<0.001 for difference between men and women). hs-CRP was significantly associated with several conventional CVRF, and particularly strongly with markers of adiposity. With regards to renal markers, hs-CRP was strongly associated with cystatin C and with microalbuminuria but not with creatinine. hs-CRP was not associated with IMT. CONCLUSIONS: Serum concentration of hs-CRP was significantly associated with sex, several CVRF and selected renal function markers, which extends similar findings in Europe and in North America to a population in the African region. These findings can contribute to guide recommendations for the use of hs-CRP in clinical practice in the region.

The peroxisome proliferator-activated receptors at the cross-road of diet and hormonal signalling.

The peroxisome proliferator-activated receptors (PPARs) are members of the steroid/thyroid nuclear receptor superfamily of ligand-activated transcription factors. To date, three isotypes have been identified, alpha, beta and gamma, encoded by three different genes. The alpha isotype is expressed at high levels in the liver where it has a role in lipid oxidation. Its expression and activity follow a diurnal rhythm that parallels the circulating levels of corticosterone in the bloodstream. The gamma isotype on the other hand, is mainly expressed in adipose tissue and has a critical role in adipocyte differentiation and lipid storage. The function of the ubiquitously expressed isotype, PPAR beta, remains to be determined. Besides fulfilling different roles in lipid metabolism, the different PPAR isotypes also have different ligand specificities. A new approach to identify ligands was developed based on the ligand-dependent interaction of PPAR with the recently characterized co-activator SRC-1. This so-called CARLA assay has allowed the identification of fatty acids and eicosanoids as PPAR ligands. Although the evidence clearly links PPAR isotypes to distinct functions, the molecular basis for this isotype-specificity is still unclear. All three isotypes are able to bind the same consensus response element, formed by a direct repeat of two AGGTCA hexamers separated by one base, though with different affinities. We recently demonstrated that besides the core DR-1 element, the 5' flanking sequence should be included in the definition of a PPRE. Interestingly, the presence of this flanking sequence is of particular importance in the context of PPAR alpha binding. Moreover, it reflects the polarity of the PPAR-RXR heterodimer on DNA, with PPAR binding to the 5' half-site and RXR binding to the 3' half-site. This unusual polarity may confer unique properties to the bound heterodimer with respect to ligand binding and interaction with co-activators and corepressors.

A new perspective on the evolutionary history of western European Sorex araneus group revealed by paternal and maternal molecular markers.

The species of the common shrew (Sorex araneus) group are morphologically very similar, but have undergone a spectacular chromosomal evolution. We investigate here the evolutionary history of the Sorex araneus group distributed in western Europe. In particular, we clarify the position of a difficult species, S. granarius, using sex-specific (mtDNA and Y-chromosome) markers. The karyotype of S. granarius is generally considered similar to the common ancestor of the restricted group considered here. The mtDNA data (1.4 kb) confirms the close relationship between S. granarius and S. araneus sensu stricto (hereafter S. araneus s.s.), but the Y-chromosome (3.4 kb) produces a quite different picture: S. granarius is closely related to another species, S. coronatus. Comparison of mtDNA and Y-chromosome phylogenies suggests that the genetic and chromosomal evolution in this group are disconnected processes. The evolutionary history of the south-western European populations of the S. araneus group can only be understood considering secondary contacts between taxa after their divergence, implying genetic exchanges by means of hybridization and/or introgression.

Markers for sepsis diagnosis in the forensic setting: state of the art.

Reliable diagnoses of sepsis remain challenging in forensic pathology routine despite improved methods of sample collection and extensive biochemical and immunohistochemical investigations. Macroscopic findings may be elusive and have an infectious or non-infectious origin. Blood culture results can be difficult to interpret due to postmortem contamination or bacterial translocation. Lastly, peripheral and cardiac blood may be unavailable during autopsy. Procalcitonin, C-reactive protein, and interleukin-6 can be measured in biological fluids collected during autopsy and may be used as in clinical practice for diagnostic purposes. However, concentrations of these parameters may be increased due to etiologies other than bacterial infections, indicating that a combination of biomarkers could more effectively discriminate non-infectious from infectious inflammations. In this article, we propose a review of the literature pertaining to the diagnostic performance of classical and novel biomarkers of inflammation and bacterial infection in the forensic setting.