76 research outputs found
Serum undercarboxylated osteocalcin was inversely associated with plasma glucose level and fat mass in type 2 diabetes mellitus
No full textMonitoring of plant suckers in vineyards with chromotropic traps: factors which influence capture.
No full textHuman Physiology During Exposure to the Cave Environment : a Systematic Review With Implications for Aerospace Medicine
No full textBackground: Successful long-duration missions outside low-Earth orbit will depend on technical and physiological challenges under abnormal environmental conditions. Caves, characterized by absence of light, confinement, three-dimensional human movement and long-duration isolation, are identifiably one of the earliest examples of scientific enquiry into space analogs. However, little is known about the holistic human physiological response during cave exploration or prolonged habitation. Objectives: The aim of our review was to conduct a systematic bibliographic research review of the effects of short and prolonged exposure to a cave environment on human physiology, with a view to extend the results to implications for human planetary exploration missions. Methods: A systematic search was conducted following the structured PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for electronic databases. Results: The search retrieved 1,519 studies. There were 50 articles selected for further consideration, of which 31 met our inclusion criteria. Short-term cave exposure studies have investigated visual dysfunction, cardiovascular, endocrine-metabolic, immunologic-hematological and muscular responses in humans. Augmentations of heart rate, muscular damage, initial anticipatory stress reaction and inflammatory responses were reported during caving activity. Prolonged exposure studies mainly investigated whether biological rhythms persist or desist in the absence of standard environmental conditions. Changes were evident in estimated vs. actual rest-activity cycle periods and external desynchronization, body temperature, performance reaction time and heart rate cycles. All studies have shown a marked methodological heterogeneity and lack reproduction under controlled conditions. Conclusions: This review facilitates a further comparison of the proposed physiological impact of a subterranean space analog environment, with existing knowledge in related disciplines pertaining to human operative preparation under challenging environmental conditions. This comprehensive overview should stimulate more reproducible research on this topic and offer the opportunity to advance study design and focus future human research in the cave environment on noteworthy, reproducible projects
Cardiac autonomic adjustement to normal human pregnancy : insight from spectral analysis of R-R interval and systolic arterial pressure variability
No full textOBJECTIVE: To assess the adaptation in autonomic control mechanisms that accompanies the marked haemodynamic changes, such as increases in cardiac size and output, that occur in the course of normal human pregnancy. DESIGN: We studied 14 healthy pregnant women (aged 30+/-1 years) before the 6th week (early stage) and within weeks 32-34 (late stage) of pregnancy, while they were at rest or in a state of active orthostatism (standing), which enhances sympathetic activity. METHODS: We used echocardiography to assess cardiac volumes and mass, and spectral analysis of the R-R interval and systolic arterial pressure variability to obtain indices of autonomic regulation of the circulation. This non-invasive methodology, recently validated with direct recordings of muscle sympathetic nerve activity, furnishes quantitative markers of sympathetic modulation of the sino-atrial node (low frequency component, LF in normalized units, nu), vagal modulation (high frequency component, HF in normalized units, nu) and the overall arterial pressure-heart rate baroreflex gain (alpha index). RESULTS: Late pregnancy was characterized by an increase in cardiac size and volumes and by a reduction of R-R interval, R-R interval variance and the alpha index, together with an increase in the LF/HF ratio (from 1.4+/-0.4 to 5.6+/-1.9). Changes in markers of autonomic modulation of the sino-atrial node normally induced by the standing position were blunted. CONCLUSIONS: The late stage of normal human pregnancy appears to be characterized by alterations in the autonomic control of the circulation and by attenuated responsiveness to active standing, possibly as a consequence of the accompanying increase in cardiac size
Comment on: Acute kidney injury and rhabdomyolysis: a role for the regulator of G-protein signaling (RGS)-2
No full textEffects of type 5-phosphodiesterase inhibition on energy metabolism and mitochondrial biogenesis in human adipose tissue ex vivo.
No full textBone Mineral Density and Testicular Failure: Evidence for a Role of Vitamin D 25-Hydroxylase in Human Testis
No full textWorking Hypothesis: Mutations in the CYP2R1 gene, highly expressed in the testis and encoding vitamin D 25-hydroxylase, result in a vitamin D deficiency and a defective calcium homeostasis leading to rickets. Objective: Our aim was to investigate CYP2R1 expression in pathological testis samples and relate this to vitamin D metabolism in testiculopathic patients. Design, Patients, Setting: Testis samples for in vitro study and 98 young men were transversally evaluated at Padova's Center for Male Gamete Cryopreservation. Methods: CYP2R1 mRNA expression and protein production were evaluated by quantitative RTPCR, Western blot analysis, and immunofluorescence. Hormonal and bone-marker levels, and bone densitometry by dual-energy x-ray absorptiometry, were determined in patients with Sertoli-cellonly syndrome and severe hypospermatogenesis. Results:Wefound a lower gene and protein expression of CYP2R1 in samples with hypospermatogenesis and Sertoli-cell-only syndrome (P < 0.05) and a colocalization with INSL-3, a Leydig cell marker, at immunofluorescence. In all testiculopathic patients 25-hydroxyvitamin D levels were significantly lower and PTH levels higher compared to controls (P < 0.05). Furthermore, testiculopathic patients showed osteopenia and osteoporosis despite normal testosterone levels compared with controls both with increased bone-marker levels and altered dual-energy x-ray absorptiometry in the femoral neck and lumbar spine (for all parameters, P < 0.05). Conclusions: Our data show an association between testiculopathy and alteration of the bone status, despite unvaried androgen and estrogen levels and no other evident cause of vitamin D reduction. Further studies in larger cohorts are needed to confirm our results. Copyright © 2011 by The Endocrine Society
Evidence for Osteocalcin Production by Adipose Tissue and Its Role in Human Metabolism
No full textCONTEXT:
The adipose tissue (AT), which is an endocrine organ, is linked to several metabolic abnormalities. Undercarboxylated osteocalcin (ucOCN) regulates insulin and adiponectin secretion.
OBJECTIVE:
Our objective was to investigate the involvement of OCN in obesity and to evaluate, in vitro and ex vivo, the role of AT in the modulation of this endocrine circuit.
DESIGN, PATIENTS, AND SETTING:
This transversal study involved 83 male subjects, divided according to the World Health Organization body mass index classification, evaluated at Padova's Obesity Outpatient Clinic.
METHODS:
OCN, both undercarboxylated (ucOCN) and carboxylated (cOCN) forms, was measured in serum by ELISA. OCN mRNA expression and protein production were measured by quantitative RT-PCR and immunohistochemistry during in vitro adipogenesis and in sc AT (SAT) and omental AT (OAT) from normal adult men. cOCN and ucOCN release by AT in a simple growth medium was verified by ELISA.
RESULTS:
Overweight and obese patients had a lower ucOCN and ucOC/OCN ratio. In the whole cohort, ucOCN/OCN ratio was negatively correlated to body mass index (rho = -0.233; P < 0.05). OCN mRNA was present in SAT and OAT and during all stages of adipogenesis, with higher expression in the first steps. Immunohistochemistry confirmed the expression of OCN protein. Both SAT and OAT were able to release cOCN and ucOCN.
CONCLUSIONS:
Our data support a pathophysiological link between ucOCN and cOCN balance and obesity. OCN is present in the first phases of adipogenesis but also in human AT ex vivo. AT releases, in vitro, both ucOCN and cOCN, suggesting a possible link between AT and OCN in the regulation of metabolism
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