352 research outputs found

    Distinguishing colour variants of <i>Serapias perez-chiscanoi</i> (Orchidaceae) from related taxa on the Iberian Peninsula

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    Serapias perez-chiscanoi has a stable and uniform appearance with green flowers. Throughout its distribution area, however, plants have been found with deviant pink to red flowers that show similarities with other taxa that are occasionally pale flowered. S. perez-chiscanoi is easy to differentiate from S. cordigera subsp. cordigera by the colour of the flowers (S. cordigera subsp. cordigera has red to purple flowers) and the fact that the hypochile dimensions of S. perez-chiscanoi are significantly smaller. It is, however, more difficult to distinguish it from individuals of S. cordigera subsp. gentilii with pale flowers, which occur frequently. The two taxa differ in colour pattern and floral dimensions, especially the hypochile length, which is shorter in S. perez-chiscanoi. Pale-flowered individuals of another species, S. parviflora, are easily distinguished by their significantly smaller flowers. S. perez-chiscanoi occurs in Spain in the autonomous regions of Extremadura and Castilla-La Mancha and in Portugal, S. cordigera subsp. gentilii seems to occur along the coastal regions of SW Portugal, while S. cordigera subsp. cordigera and S. parviflora are distributed throughout the Iberian Peninsula

    Association testing by haplotype-sharing methods applicable to whole-genome analysis

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    We propose two new haplotype-sharing methods for identifying disease loci: the haplotype sharing statistic (HSS), which compares length of shared haplotypes between cases and controls, and the CROSS test, which tests whether a case and a control haplotype show less sharing than two random haplotypes. The significance of the HSS is determined using a variance estimate from the theory of U-statistics, whereas the significance of the CROSS test is estimated from a sequential randomization procedure. Both methods are fast and hence practical, even for whole-genome screens with high marker densities. We analyzed data sets of Problems 2 and 3 of Genetic Analysis Workshop 15 and compared HSS and CROSS to conventional association methods. Problem 2 provided a data set of 2300 single-nucleotide polymorphisms (SNPs) in a 10-Mb region of chromosome 18q, which had shown linkage evidence for rheumatoid arthritis. The CROSS test detected a significant association at approximately position 4407 kb. This was supported by single-marker association and HSS. The CROSS test outperformed them both with respect to significance level and signal-to-noise ratio. A 20-kb candidate region could be identified. Problem 3 provided a simulated 10 k SNP data set covering the whole genome. Three known candidate regions for rheumatoid arthritis were detected. Again, the CROSS test gave the most significant results. Furthermore, both the HSS and the CROSS showed better fine-mapping accuracy than straightforward haplotype association. In conclusion, haplotype sharing methods, particularly the CROSS test, show great promise for identifying disease gene loci

    On heating head and neck tumours using the novel clinical em applicator: the HYPERcollar

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    Abstract Purpose: Definition of all features and the potential of the novel HYPERcollar applicator system for hyperthermia treatments in the head and neck (H&N) region. Methods and Materials: The HYPERcollar applicator consists of 1) an antenna ring, 2) a waterbolus system and 3) a positioning system. The specific absorption rate (SAR) profile of this applicator is investigated by performing infra-red (IR) measurements in a cylindrical phantom. Mandatory patient-specific treatment planning is performed as an object lesson to a patient with a laryngeal tumour and an artificial lymph node metastasis. Results: The comfort tests with healthy volunteers have revealed that the applicator provides su±cient comfort to maintain in treatment position for an hour: in our center the standard hyperthermia treatment duration. We further established that a central focus in the neck can be obtained, with 50% iso-SAR lengths of 3.5cm in transversal directions and 9-11cm in the axial direction (z). Using treatment planning by detailed electromagnetic simulations, we showed that the SAR pattern can be optimized to enable simultaneous encompassing a primary laryngeal tumour and a lymph node metastasis at the 25% iso-SAR level. Conclusions: A site-specific H&N applicator was designed that enables good control and sufficient possibilities for optimizing the SAR pattern. In an ongoing clinical feasibility study we will investigate the possibilities of heating various target regions in the neck with this apparatus

    COVID-19-associated immune thrombocytopenia

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    Thrombocytopenia is a risk factor for increased morbidity and mortality in patients with the new severe acute respiratory syndrome corona virus, SARS-CoV-2 infection (COVID-19 infection).1 Thrombocytopenia in COVID-19 patients may be caused by disseminated intravascular coagulation (DIC), sepsis or drug-induced. Recently a single case report suggested immune thrombocytopenia (ITP) may be associated with COVID-19 infection.2 ITP is a rare autoimmune disease characterized by a platelet count < 100x109/L, leading to an increased bleeding risk.3 Several risk factors have been described for ITP including environmental (e.g. infection, malignancy and drugs) and genetic predisposition.4 We report here the first case series of three patients with ITP associated with COVID-19 infection

    Interrelationships Between Pituitary Hormones as Assessed From 24-hour Serum Concentrations in Healthy Older Subjects

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    Context: Hormones of the hypothalamic-pituitary-target gland axes are mostly investigated separately, whereas the interplay between hormones might be as important as each separate hormonal axis.Objective: Our aim is to determine the interrelationships between GH, TSH, ACTH, and cortisol in healthy older individuals.Design: We made use of 24-hour hormone serum concentrations assessed with intervals of 10 minutes from 38 healthy older individuals with a mean age (SD) of 65.1 (5.1) years from the Leiden Longevity Study. Cross-correlation analyses were performed to assess the relative strength between 2 24-hour hormone serum concentration series for all possible time shifts. Cross-approximate entropy was used to assess pattern synchronicity between 2 24-hour hormone serum concentration series.Results: Within an interlinked hormonal axis, ACTH and cortisol were positively correlated with a mean (95% confidence interval) correlation coefficient of 0.78 (0.74-0.81) with cortisol following ACTH concentrations with a delay of 10 minutes. Between different hormonal axes, we observed a negative correlation coefficient between cortisol and TSH of -0.30 (-0.36 to -0.25) with TSH following cortisol concentrations with a delay of 170 minutes. Furthermore, a positive mean (95% confidence interval) correlation coefficient of 0.29 (0.22-0.37) was found between TSH and GH concentrations without any delay. Moreover, cross-approximate entropy analyses showed that GH and cortisol exhibit synchronous serum concentration patterns.Conclusions: This study demonstrates that interrelations between hormones from interlinked as well as different hypothalamic-pituitary-target gland axes are observed in healthy older individuals. More research is needed to determine the biological meaning and clinical consequences of these observations.Pathophysiology, epidemiology and therapy of agein
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