896 resultados para Invertebrate availability


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OBJECTIVE: While systemic glucocorticoids compromise bone metabolism, altered intracellular cortisol availability may also contribute to the pathogenesis of primary male osteoporosis (MO). The objective of this study was to assess whether intracellular cortisol availability is increased in MO due to a distorted local cortisol metabolism. METHODS: Forty-one patients with MO were compared with age- and BMI-matched non-osteoporotic subjects after excluding overt systemic hypercortisolism (N = 41). Cortisol, cortisone and the respective tetrahydro-, 5α-tetrahydro- and total cortisol metabolites were analysed by GC-MS in 24 h urine. Apparent 11β-hydroxysteroid dehydrogenase (11β-HSD) enzyme activities, excretion of cortisol metabolites and calcium, and fractional urinary calcium excretion were assessed and related to BMD. RESULTS: Fractional and total urinary calcium excretion negatively correlated with BMD at all (P < 0.05) and at three of five (P < 0.05) measurement sites, respectively. While systemic cortisol was unchanged, apparent 11β-HSD enzyme activity in MO patients (P < 0.01) suggested increased intracellular cortisol availability. Total and fractional urinary calcium excretion was higher, with apparent 11β-HSD enzyme activities consistent with an enhanced intracellular cortisol availability (P < 0.05). CONCLUSION: Apparent 11β-HSD enzyme activities consistent with increased intracellular cortisol availability correlated with urinary calcium loss and reduced bone mineral density in MO. The changes in 11β-HSD activity were associated with both the fractional calcium excretion, suggesting altered renal calcium handling, and the absolute urinary calcium excretion. Both mechanisms could result in a marked bone calcium deficiency if insufficiently compensated for by intestinal calcium uptake.

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Legislation influences the availability of embryos for research. The law in Switzerland, and in some other European countries, is restrictive concerning medically assisted reproduction and stem cell research. Swiss law prohibits the creation of embryos for research purposes. It permits the derivation of human embryonic stem cells for research from surplus embryos but prohibits research with intact surplus embryos and embryo donation to other couples. Swiss law defines all embryos generated during a reproductive cycle and not used for reproduction as surplus embryos. The aim of this study was to evaluate the surplus embryos generated in Switzerland in 2003. A detailed questionnaire was sent to all registered IVF units in Switzerland (n = 22). 11727 embryos were generated during 2003. Of these, 93.5% were transferred into the uterus and 0.4% were cryopreserved. The remaining 6.1% (n = 711) became surplus. Of these, 2.7% were transferred intravaginally and the rest discarded due to poor quality (1.6%), development arrest (1.5%), renunciation by the couple (0.2%) or for other reasons (0.1%). The number of surplus embryos in Switzerland in 2003 was evaluated. Most surplus embryos became so during a therapeutic cycle. The restrictive legal regulation decreases the availability of human embryos for research.

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Preeclampsia is a hypertensive disorder unique to pregnancy and remains the leading cause of maternal and fetal morbidity and mortality. Despite active research, the etiology of this disease remains still an enigma. There is increasing evidence that a combination of several factors is responsible for the development of preeclampsia. In this review, we discuss the role of aldosterone in the regulation of body fluid in pregnancy and preeclampsia. Aldosterone is produced by the enzyme aldosterone synthase and competes with cortisol and progesterone for the mineralocorticoid receptor, thus affecting sodium reabsorption and maternal volume expansion. Aldosterone seems to play a pivotal role in controlling blood pressure during pregnancy and to contribute to the well-being of the mother-to-be. Novel findings in understanding the underlying causes of preeclampsia provide a rationale for future novel prophylactic and therapeutic interventions in the treatment of this pregnancy-associated disease.

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Groundwater pumping from aquifers in hydraulic connection with nearby streams is known to cause adverse impacts by decreasing flows to levels below those necessary to maintain aquatic ecosystems. The recent passage of the Great Lakes--St. Lawrence River Basin Water Resources Compact has brought attention to this issue in the Great Lakes region. In particular, the legislation requires the Great Lakes states to enact measures for limiting water withdrawals that can cause adverse ecosystem impacts. This study explores how both hydrogeologic and environmental flow limitations constrain groundwater availability in the Great Lakes Basin. A methodology for calculating maximum allowable pumping rates is presented. Groundwater availability across the basin is shown to be constrained by a combination of hydrogeologic yield and environmental flow limitations varying over both local and regional scales. The results are sensitive to factors such as pumping time and streamflow depletion limits as well as streambed conductance. Understanding how these restrictions constrain groundwater usage and which hydrogeologic characteristics and spatial variables have the most influence on potential streamflow depletions has important water resources policy and management implications.

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BACKGROUND ; AIMS: Iron perturbations are frequently observed in nonalcoholic fatty liver disease (NAFLD). We aimed to investigate a potential association of copper status with disturbances of iron homeostasis in NAFLD. METHODS: We retrospectively studied 140 NAFLD patients and 25 control subjects. Biochemical and hepatic iron and copper parameters were analyzed. Hepatic expression of iron regulatory molecules was investigated in liver biopsy specimens by reverse-transcription polymerase chain reaction and Western blot analysis. RESULTS: NAFLD patients had lower hepatic copper concentrations than control subjects (21.9 +/- 9.8 vs 29.6 +/- 5.1 microg/g; P = .002). NAFLD patients with low serum and liver copper concentrations presented with higher serum ferritin levels (606.7 +/- 265.8 vs 224.2 +/- 176.0 mg/L; P < .001), increased prevalence of siderosis in liver biopsy specimens (36/46 vs 10/47 patients; P < .001), and with elevated hepatic iron concentrations (1184.4 +/- 842.7 vs 319.9 +/- 451.3 microg/g; P = .020). Lower serum concentrations of the copper-dependent ferroxidase ceruloplasmin (21.7 +/- 4.1 vs 30.4 +/- 6.4 mg/dL; P < .001) and decreased liver ferroportin (FP-1; P = .009) messenger RNA expression were found in these patients compared with NAFLD patients with high liver or serum copper concentrations. Accordingly, in rats, a reduced dietary copper intake was paralleled by a decreased hepatic FP-1 protein expression. CONCLUSIONS: A significant proportion of NAFLD patients should be considered copper deficient. Our results indicate that copper status is linked to iron homeostasis in NAFLD, suggesting that low copper bioavailability causes increased hepatic iron stores via decreased FP-1 expression and ceruloplasmin ferroxidase activity thus blocking liver iron export in copper-deficient subjects.

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To explore relevant changes in unexplained intraoperative bleeding, we evaluated elements of the final steps of the coagulation cascade in 226 consecutive patients undergoing elective surgery. Patients were stratified for the occurrence of unexplained intraoperative bleeding according to predefined criteria. Twenty patients (8.8%) developed unexplained bleeding. The median intraoperative blood loss was 1350 mL (bleeders) and 400 mL (nonbleeders) (P < 0.001). Fibrinogen and Factor XIII (F. XIII) were more rapidly consumed in bleeders (P < 0.001). Soluble fibrin formation (fibrin monomer) was increased in bleeders throughout surgery (P < or = 0.014). However, F. XIII availability per unit thrombin generated was significantly decreased in bleeders before, during, and after surgery (P < or = 0.051). Computerized thrombelastography showed a parallel, significant reduction in clot firmness. We suggest that mild preexisting coagulopathy is not rare in surgical patients and probably can result in clinically relevant intraoperative bleeding. This hemostatic disorder shows impaired clot firmness, probably secondary to decreased cross-linking (due to a loss of F. XIII, both in absolute measures and per unit thrombin generated). We suggest that the application of F. XIII might be worthwhile to test in a prospective clinical trial to increase clot firmness in patients at risk for this intraoperative coagulopathy.

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In recent years, the ability to respond to real time changes in operations and reconfigurability in equipment are likely to become essential characteristics for next generation intralogistics systems as well as the level of automation, cost effectiveness and maximum throughput. In order to cope with turbulences and the increasing level of dynamic conditions, future intralogistics systems have to feature short reaction times, high flexibility in processes and the ability to adapt to frequent changes. The increasing autonomy and complexity in processes of today’s intralogistics systems requires new and innovative management approaches, which allow a fast response to (un)anticipated events and adaptation to changing environment in order to reduce the negative consequences of these events. The ability of a system to respond effectively a disruption depends more on the decisions taken before the event than those taken during or after. In this context, anticipatory change planning can be a usable approach for managers to make contingency plans for intralogistics systems to deal with the rapidly changing marketplace. This paper proposes a simulation-based decision making framework for the anticipatory change planning of intralogistics systems. This approach includes the quantitative assessments based on the simulation in defined scenarios as well as the analysis of performance availability that combines the flexibility corridors of different performance dimensions. The implementation of the approach is illustrated on a new intralogistics technology called the Cellular Transport System.