455 research outputs found
Resolution of the clinical features of tyrosinemia following orthotopic liver transplantation for hepatoma
The clinical history before transplantation and subsequent clinical and biochemical course of 3 children and one adult with hereditary tyrosinemia treated by orthotopic hepatic transplantation is described. All four patients are now free of their previous dietary restrictions and appear to be cured of both their metabolic disease and their hepatic neoplasm. © 1986 Elsevier Science Publishers B.V. All rights reserved
Comparing Word Processing Times in Naming, Lexical Decision, and Progressive Demasking: Evidence from Chronolex
We report performance measures for lexical decision (LD), word naming (NMG), and progressive demasking (PDM) for a large sample of monosyllabic monomorphemic French words (Nâ=â1,482). We compare the tasks and also examine the impact of word length, word frequency, initial phoneme, orthographic and phonological distance to neighbors, age-of-acquisition, and subjective frequency. Our results show that objective word frequency is by far the most important variable to predict reaction times in LD. For word naming, it is the first phoneme. PDM was more influenced by a semantic variable (word imageability) than LD, but was also affected to a much greater extent by perceptual variables (word length, first phoneme/letters). This may reduce its usefulness as a psycholinguistic word recognition task
Molecular genetics and pathophysiology of 17 beta-hydroxysteroid dehydrogenase 3 deficiency.
Autosomal recessive mutations in the 17 beta-hydroxysteroid dehydrogenase 3 gene impair the formation of testosterone in the fetal testis and give rise to genetic males with female external genitalia. Such individuals are usually raised as females, but virilize at the time of expected puberty as the result of increases in serum testosterone. Here we describe mutations in 12 additional subjects/families with this disorder. The 14 mutations characterized to date include 10 missense mutations, 3 splice junction abnormalities, and 1 small deletion that results in a frame shift. Three of these mutations have occurred in more than 1 family. Complementary DNAs incorporating 9 of the 10 missense mutations have been constructed and expressed in reporter cells; 8 of the 9 missense mutations cause almost complete loss of enzymatic activity. In 2 subjects with loss of function, missense mutations testosterone levels in testicular venous blood were very low. Considered together, these findings strongly suggest that the common mechanism for testosterone formation in postpubertal subjects with this disorder is the conversion of circulating androstenedione to testosterone by one or more of the unaffected 17 beta-hydroxysteroid dehydrogenase isoenzymes
Dipolar interaction between two-dimensional magnetic particles
We determine the effective dipolar interaction between single domain
two-dimensional ferromagnetic particles (islands or dots), taking into account
their finite size. The first correction term decays as 1/D^5, where D is the
distance between particles. If the particles are arranged in a regular
two-dimensional array and are magnetized in plane, we show that the correction
term reinforces the antiferromagnetic character of the ground state in a square
lattice, and the ferromagnetic one in a triangular lattice. We also determine
the dipolar spin-wave spectrum and evaluate how the Curie temperature of an
ensemble of magnetic particles scales with the parameters defining the particle
array: height and size of each particle, and interparticle distance. Our
results show that dipolar coupling between particles might induce ferromagnetic
long range order at experimentally relevant temperatures. However, depending on
the size of the particles, such a collective phenomenon may be disguised by
superparamagnetism.Comment: 11 pages, 5 figure
CYP21A2 Gene Mutations in Congenital Adrenal Hyperplasia: Genotypeâphenotype correlation in Turkish children
Background: Congenital adrenal hyperplasia (CAH) due 21âhydroxylase deficiency (21âOHD) is a common autosomal recessive disorder. It is caused by defects in the CYP21A2 gene
Pubertal presentation in seven patients with congenital adrenal hyperplasia due to P450 Oxidoreductase deficiency
Context: P450 oxidoreductase (POR) is a crucial electron donor to all microsomal P450 cytochrome (CYP) enzymes including 17α-hydroxylase (CYP17A1), 21-hydroxylase (CYP21A2) and P450 aromatase. Mutant POR causes congenital adrenal hyperplasia with combined glucocorticoid and sex steroid deficiency. P450 oxidoreductase deficiency (ORD) commonly presents neonatally, with disordered sex development in both sexes, skeletal malformations, and glucocorticoid deficiency. \ud
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Objective: The aim of the study was to describe the clinical and biochemical characteristics of ORD during puberty. \ud
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Design: Clinical, biochemical, and genetic assessment of seven ORD patients (five females, two males) presenting during puberty was conducted. \ud
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Results: Predominant findings in females were incomplete pubertal development (four of five) and large ovarian cysts (five of five) prone to spontaneous rupture, in some only resolving after combined treatment with estrogen/progestin, GnRH superagonists, and glucocorticoids. Pubertal development in the two boys was more mildly affected, with some spontaneous progression. Urinary steroid profiling revealed combined CYP17A1 and CYP21A2 deficiencies indicative of ORD in all patients; all but one failed to mount an appropriate cortisol response to ACTH stimulation indicative of adrenal insufficiency. Diagnosis of ORD was confirmed by direct sequencing, demonstrating disease-causing POR mutations. \ud
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Conclusion: Delayed and disordered puberty can be the first sign leading to a diagnosis of ORD. Appropriate testosterone production during puberty in affected boys but manifest primary hypogonadism in girls with ORD may indicate that testicular steroidogenesis is less dependent on POR than adrenal and ovarian steroidogenesis. Ovarian cysts in pubertal girls may be driven not only by high gonadotropins but possibly also by impaired CYP51A1-mediated production of meiosis-activating sterols due to mutant POR
Risk of Injury in Royal Air Force Training: Does Sex Really Matter?
IntroductionMusculoskeletal injuries are common during military and other occupational physical training programs. Employers have a duty of care to reduce employeesâ injury risk, where females tend to be at greater risk than males. However, quantification of principle co-factors influencing the sexâinjury association, and their relative importance, remain poorly defined. Injury risk co-factors were investigated during Royal Air Force (RAF) recruit training to inform the strategic prioritization of mitigation strategies.Material and MethodsA cohort of 1,193 (males n = 990 (83%); females n = 203 (17%)) recruits, undertaking Phase-1 military training, were prospectively monitored for injury occurrence. The primary independent variable was sex, and potential confounders (fitness, smoking, anthropometric measures, education attainment) were assessed pre-training. Generalized linear models were used to assess associations between sex and injury.ResultsIn total, 31% of recruits (28% males; 49% females) presented at least one injury during training. Females had a two-fold greater unadjusted risk of injury during training than males (RR = 1.77; 95% CI 1.49â2.10). After anthropometric, lifestyle and education measures were included in the model, the excess risk decreased by 34%, but the associations continued to be statistically significant. In contrast, when aerobic fitness was adjusted, an inverse association was identified; the injury risk was 40% lower in females compared with males (RR = 0.59; 95% CI: 0.42â0.83).ConclusionsPhysical fitness was the most important confounder with respect to differences in malesâ and femalesâ injury risk, rather than sex alone. Mitigation to reduce this risk should, therefore, focus upon physical training, complemented by healthy lifestyle interventions
Effects of vessel traffic on relative abundance and behaviour of cetaceans : the case of the bottlenose dolphins in the Archipelago de La Maddalena, north-western Mediterranean sea
Acknowledgements This study was part of the Tursiops Project of the Dolphin Research Centre of Caprera, La Maddalena. Financial and logistical support was provided by the Centro Turistico Studentesco (CTS) and by the National Park of the Archipelago de La Maddalena. We thank the Natural Reserve of Bocche di Bonifacio for the support provided during data collection. The authors thank the numerous volunteers of the Caprera Dolphin Research Centre and especially Marco Ferraro, Mirko Ugo, Angela Pira and Maurizio Piras whose assistance during field observation and skills as a boat driver were invaluable.Peer reviewedPostprin
Comparing Genetic Variation among Latin American Immigrants: Implications for Forensic Casework in the Arizona- and Texas-MĂ©xico Borderlands
The humanitarian crisis on the United States-MĂ©xico border is a long standing and evolving crisis in which nearly 8,000 deaths have been reported in the last two decades. These deaths are largely distributed across the Arizona-MĂ©xico and Texas-MĂ©xico border regions where demographic trends for immigrants attempting to cross into the U.S. have shifted dramatically. The demographic change and volume of immigrants seeking shelter in the U.S. presents new challenges for the forensic practitioners entrusted with the identification of individuals who lose their lives during the final segment of their journey. Within this Border context, the present study investigates how genetic variation inferred from forensically significant microsatellites can provide valuable information on regions of origin for unidentified remains on the group level. To explore how we can mobilize these genetic data to inform identification strategies, we conduct a comparative genetic analysis of identified and unidentified immigrant cases from the Arizona- and Texas-MĂ©xico contexts, as well as 27 other Latin American groups. Allele frequencies were utilized to calculate FST, and relationships were visually depicted in a multidimensional scaling plot. A Spearman correlation coefficient analysis assessed the strength and significance of population relationships and an agglomerative clustering analysis assessed population clusters. Results indicate that Arizona-MĂ©xico immigrants have the strongest relationship (\u3e80%) with groups from El Salvador, Guatemala, MĂ©xico, and an indigenous group from Southern MĂ©xico. Texas-MĂ©xico immigrants have the strongest relationships (\u3e80%) with groups from Belize, Colombia, Costa Rica, El Salvador, Guatemala, Honduras, and Nicaragua. These findings agree with, and are discussed in comparison to, previously reported demographic trends, population genetics research, and population history analyses. We emphasize the utility and necessity of coupling genetic variation research with a nuanced anthropological perspective for identification processes in the U.S-MĂ©xico border context
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