86 research outputs found
Case report of a primary subcutaneous melanoma:a surprising entity for a subcutaneous nodule
INTRODUCTION: A melanoma can originate at the subcutis without any visible skin lesion. CASE PRESENTATION: A 73-year old patient came to the outpatient clinic with a subcutaneous nodule on the right thigh without any visible lesion of the skin. It turned out to be a primary subcutaneous melanoma that could be classified as a primary dermal melanoma (PDM). DISCUSSION: A PDM is a very rare subtype of melanoma that stands out for its excellent prognosis in comparison to cutaneous melanomas. No valid reliable staging system or treatment guideline exists for this entity, Breslow depth might overestimate the clinical aggressiveness possibly leading to overtreatment. CONCLUSION: It is of great importance for the clinician to be familiar with a primary dermal melanoma. It deserves an appropriate place in the current AJCC system and a treatment guideline for this unique melanoma subtype with relativity excellent prognosis would be beneficial
The fate of the homoctenids (Tentaculitoidea) during the Frasnian-Famennian mass extinction (Late Devonian)
The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals which are amongst the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian-Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian-Famennian boundary sections have been studied, in Poland, Germany, France, and the United States. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian “Upper Kellwasser Event”. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here
Free flux flow resistivity in strongly overdoped high-T_c cuprate; purely viscous motion of the vortices in semiclassical d-wave superconductor
We report the free flux flow (FFF) resistivity associated with a purely
viscous motion of the vortices in moderately clean d-wave superconductor
Bi:2201 in the strongly overdoped regime (T_c=16K) for a wide range of the
magnetic field in the vortex state. The FFF resistivity is obtained by
measuring the microwave surface impedance at different microwave frequencies.
It is found that the FFF resistivity is remarkably different from that of
conventional s-wave superconductors. At low fields (H<0.2H_c2) the FFF
resistivity increases linearly with H with a coefficient which is far larger
than that found in conventional s-wave superconductors. At higher fields, the
FFF resistivity increases in proportion to \sqrt H up to H_c2. Based on these
results, the energy dissipation mechanism associated with the viscous vortex
motion in "semiclassical" d-wave superconductors with gap nodes is discussed.
Two possible scenarios are put forth for these field dependence; the
enhancement of the quasiparticle relaxation rate and the reduction of the
number of the quasiparticles participating the energy dissipation in d-wave
vortex state.Comment: 9 pages 7 figures, to appear in Phys. Rev.
Design, construction and characterization of a set of insulated bacterial promoters
We have generated a series of variable-strength, constitutive, bacterial promoters that act predictably in different sequence contexts, span two orders of magnitude in strength and contain convenient sites for cloning and the introduction of downstream open-reading frames. Importantly, their design insulates these promoters from the stimulatory or repressive effects of many 5′- or 3′-sequence elements. We show that different promoters from our library produce constant relative levels of two different proteins in multiple genetic contexts. This set of promoters should be a useful resource for the synthetic-biology community
Study protocol for two randomised controlled trials evaluating the effects of Cerclage in the reduction of extreme preterm birth and perinatal mortality in twin pregnancies with a short cervix or dilatation:The TWIN Cerclage studies
Introduction:Twin pregnancies have a high risk of extreme preterm birth (PTB) at less than 28 weeks of gestation, which is associated with increased risk of neonatal morbidity and mortality. Currently there is a lack of effective treatments for women with a twin pregnancy and a short cervix or cervical dilatation. A possible effective surgical method to reduce extreme PTB in twin pregnancies with an asymptomatic short cervix or dilatation at midpregnancy is the placement of a vaginal cerclage. Methods and analysis: We designed two multicentre randomised trials involving eight hospitals in the Netherlands (sites in other countries may be added at a later date). Women older than 16 years with a twin pregnancy at <24 weeks of gestation and an asymptomatic short cervix of ≤25 mm or cervical dilatation will be randomly allocated (1:1) to both trials on vaginal cerclage and standard treatment according to the current Dutch Society of Obstetrics and Gynaecology guideline (no cerclage). Permuted blocks sized 2 and 4 will be used to minimise the risk of disbalance. The primary outcome measure is PTB of <28 weeks. Analyses will be by intention to treat. The first trial is to demonstrate a risk reduction from 25% to 10% in the short cervix group, for which 194 patients need to be recruited. The second trial is to demonstrate a risk reduction from 80% to 35% in the dilatation group and will recruit 44 women. A cost-effectiveness analysis will be performed from a societal perspective. Ethics and dissemination: This study has been approved by the Research Ethics Committees in the Netherlands on 3/30/2023. Participants will be required to sign an informed consent form. The results will be presented at conferences and published in a peer-reviewed journal. Participants will be informed about the results.</p
Study protocol for two randomised controlled trials evaluating the effects of Cerclage in the reduction of extreme preterm birth and perinatal mortality in twin pregnancies with a short cervix or dilatation:The TWIN Cerclage studies
Introduction:Twin pregnancies have a high risk of extreme preterm birth (PTB) at less than 28 weeks of gestation, which is associated with increased risk of neonatal morbidity and mortality. Currently there is a lack of effective treatments for women with a twin pregnancy and a short cervix or cervical dilatation. A possible effective surgical method to reduce extreme PTB in twin pregnancies with an asymptomatic short cervix or dilatation at midpregnancy is the placement of a vaginal cerclage. Methods and analysis: We designed two multicentre randomised trials involving eight hospitals in the Netherlands (sites in other countries may be added at a later date). Women older than 16 years with a twin pregnancy at <24 weeks of gestation and an asymptomatic short cervix of ≤25 mm or cervical dilatation will be randomly allocated (1:1) to both trials on vaginal cerclage and standard treatment according to the current Dutch Society of Obstetrics and Gynaecology guideline (no cerclage). Permuted blocks sized 2 and 4 will be used to minimise the risk of disbalance. The primary outcome measure is PTB of <28 weeks. Analyses will be by intention to treat. The first trial is to demonstrate a risk reduction from 25% to 10% in the short cervix group, for which 194 patients need to be recruited. The second trial is to demonstrate a risk reduction from 80% to 35% in the dilatation group and will recruit 44 women. A cost-effectiveness analysis will be performed from a societal perspective. Ethics and dissemination: This study has been approved by the Research Ethics Committees in the Netherlands on 3/30/2023. Participants will be required to sign an informed consent form. The results will be presented at conferences and published in a peer-reviewed journal. Participants will be informed about the results.</p
A physical analysis of the Y chromosome shows no additional deletions, other than Gr/Gr, associated with testicular germ cell tumour
Testicular germ cell tumour (TGCT) is the most common malignancy in men aged 15–45 years. A small deletion on the Y chromosome known as ‘gr/gr' was shown to be associated with a two-fold increased risk of TGCT, increasing to three-fold in cases with a family history of TGCT. Additional deletions of the Y chromosome, known as AZFa, AZFb and AZFc, are described in patients with infertility; however, complete deletions of these regions have not been identified in TGCT patients. We screened the Y chromosome in a series of TGCT cases to evaluate if additional deletions of Y were implicated in TGCT susceptibility. Single copy Y chromosome STS markers with an average inter-marker spacing of 128 kb were examined in constitutional DNA of 271 index TGCT patients. Three markers showed evidence of deletions, sY1291, indicative of ‘gr/gr' (eight out of 271; 2.9%), Y-DAZ3 contained within ‘gr/gr' (21 out of 271; 7.7%) and a single deletion of the marker G66152 was identified in one TGCT case. No other markers demonstrated deletions. While several regions of the Y chromosome are known to be deleted and associated with infertility, our study provides no evidence to suggest regions of Y deletion, other than ‘gr/gr', are associated with susceptibility to TGCT in UK patients
Multi-stage genome-wide association study identifies new susceptibility locus for testicular germ cell tumour on chromosome 3q25
Recent genome-wide association studies (GWAS) and subsequent meta-analyses have identified over 25 SNPs at 18 loci, together accounting for >15% of the genetic susceptibility to testicular germ cell tumour (TGCT). To identify further common SNPs associated with TGCT, here we report a three-stage experiment, involving 4098 cases and 18 972 controls. Stage 1 comprised previously published GWAS analysis of 307 291 SNPs in 986 cases and 4946 controls. In Stage 2, we used previously published customised Illumina iSelect genotyping array (iCOGs) data across 694 SNPs in 1064 cases and 10 082 controls. Here, we report new genotyping of eight SNPs showing some evidence of association in combined analysis of Stage 1 and Stage 2 in an additional 2048 cases of TGCT and 3944 controls (Stage 3). Through fixed-effects meta-analysis across three stages, we identified a novel locus at 3q25.31 (rs1510272) demonstrating association with TGCT [per-allele odds ratio (OR) = 1.16, 95% confidence interval (CI) = 1.06-1.27; P = 1.2 × 10-9]
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Creating a population-based cohort of children born with and without congenital anomalies using birth data matched to hospital discharge databases in 11 European regions: Assessment of linkage success and data quality.
Linking routinely collected healthcare administrative data is a valuable method for conducting research on morbidity outcomes, but linkage quality and accuracy needs to be assessed for bias as the data were not collected for research. The aim of this study was to describe the rates of linking data on children with and without congenital anomalies to regional or national hospital discharge databases and to evaluate the quality of the matched data. Eleven population-based EUROCAT registries participated in a EUROlinkCAT study linking data on children with a congenital anomaly and children without congenital anomalies (reference children) born between 1995 and 2014 to administrative databases including hospital discharge records. Odds ratios (OR), adjusted by region, were estimated to assess the association of maternal and child characteristics on the likelihood of being matched. Data on 102,654 children with congenital anomalies were extracted from 11 EUROCAT registries and 2,199,379 reference children from birth registers in seven regions. Overall, 97% of children with congenital anomalies and 95% of reference children were successfully matched to administrative databases. Information on maternal age, multiple birth status, sex, gestational age and birthweight were >95% complete in the linked datasets for most regions. Compared with children born at term, those born at ≤27 weeks and 28-31 weeks were less likely to be matched (adjusted OR 0.23, 95% CI 0.21-0.25 and adjusted OR 0.75, 95% CI 0.70-0.81 respectively). For children born 32-36 weeks, those with congenital anomalies were less likely to be matched (adjusted OR 0.78, 95% CI 0.71-0.85) while reference children were more likely to be matched (adjusted OR 1.28, 95% CI 1.24-1.32). Children born to teenage mothers and mothers ≥35 years were less likely to be matched compared with mothers aged 20-34 years (adjusted ORs 0.92, 95% CI 0.88-0.96; and 0.87, 95% CI 0.86-0.89 respectively). The accuracy of linkage and the quality of the matched data suggest that these data are suitable for researching morbidity outcomes in most regions/countries. However, children born preterm and those born to mothers aged <20 and ≥35 years are less likely to be matched. While linkage to administrative databases enables identification of a reference group and long-term outcomes to be investigated, efforts are needed to improve linkages to population groups that are less likely to be linked
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