1,230 research outputs found
Impact of Gene-Gender Effects of Adrenergic Polymorphisms on Hypothalamic-Pituitary-Adrenal Axis Activity in Depressed Patients
Objective: There is overwhelming evidence that activation of the hypothalamic-pituitary-adrenal (HPA) system plays a major role in depression and cardiovascular disease in genetically susceptible individuals. We hypothesized that due to the multiple interactions between the sympathetic and the HPA systems via adrenoceptors, polymorphisms in these genes could have an impact on HPA axis activity in major depression. Methods: Using the dexamethasone/corticotrophin-releasing hormone (DEX/CRH) test, we investigated the association of alpha 2-adrenoceptor (ADRA2A -1291C -> G) and the beta 2-adrenoceptor gene (ADRB2 Arg16Gly) in 189 patients with major depression during the acute state of the disease and after remission. Results: Male ADRA2A -1291G allele homozygotes showed significant pretreatment HPA axis hyperactivity, with increased adrenocorticotropin (ACTH; F = 4.9, d.f. = 2, p = 0.009) and cortisol responses (F = 6.4, d.f. = 2, p = 0.003). In contrast, female ADRB2 Arg/Arg homozygotes had increased pretreatment ACTH (F = 7.17, d.f. = 2, p = 0.001) and cortisol (F = 8.95, d.f. = 2, p = 0.000) levels. Interestingly, in the respective genotypes, the stress hormones remained elevated in the second DEX/CRH test, despite a reduction in depressive symptoms. Conclusions: This study provides evidence that, depending on gender and polymorphisms, there is continuous HPA axis overdrive in a proportion of patients irrespective of the status of depression. Considering the importance of stress hormones for cardiovascular disorders, our data might suggest that these patients are at high risk of comorbidity between depression and cardiovascular disorders. Copyright (c) 2008 S. Karger AG, Base
Role of peripheral quantitative computed tomography in identifying disuse osteoporosis in paraplegia
Objective: Disuse osteoporosis is a major long-term health consequence of spinal cord injury (SCI) that still needs to be addressed. Its management in SCI should begin with accurate diagnosis, followed by targeted treatments in the most vulnerable subgroups. We present data quantifying disuse osteoporosis in a cross-section of the Scottish paraplegic population to identify subgroups with lowest bone mineral density (BMD).
Materials and Methods: Forty-seven people with chronic SCI at levels T2-L2 were scanned using peripheral Quantitative Computed Tomography (pQCT) at four tibial sites and two femoral sites, at the Queen Elizabeth National Spinal Injuries Unit, Glasgow (U.K.). At the distal epiphyses, trabecular BMD (BMDtrab), total BMD, total bone cross-sectional area (CSA), and bone mineral content (BMC) were determined. In the diaphyses, cortical BMD, total bone CSA, cortical CSA, and BMC were calculated. Bone, muscle and fat CSAs were estimated in the lower leg and thigh.
Results: BMDtrab decreased exponentially with time since injury, at different rates in the tibia and femur. At most sites, female paraplegics had significantly lower BMC, total bone CSA and muscle CSA than male paraplegics. Subjects with lumbar SCI tended to have lower bone values and smaller muscle CSAs than in thoracic SCI.
Conclusion: At the distal epiphyses of the tibia and femur, there is generally a rapid and extensive reduction in BMDtrab after SCI. Female subjects, and those with lumbar SCI, tend to have lower bone values than males or those with thoracic SCI, respectively.
Keywords: Bone loss, osteoporosis, paraplegia, peripheral Quantitative Computed Tomography, spinal cord injur
The Size of the Narrow-Line Emitting Region in the Seyfert 1 Galaxy NGC 5548 from Emission-Line Variability
The narrow [O III] 4959, 5007 emission-line fluxes in the spectrum of the
well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this
we show that the narrow line-emitting region has a radius of only 1-3 pc and is
denser (n ~ 10^5 cm^{-3}) than previously supposed. The [O III] line width is
consistent with virial motions at this radius given previous determinations of
the black hole mass.Since the [O III] emission-line flux is usually assumed to
be constant and is therefore used to calibrate spectroscopic monitoring data,
the variability has ramifications for the long-term secular variations of
continuum and emission-line fluxes, though it has no effect on shorter-term
reverberation studies. We present corrected optical continuum and broad Hbeta
emission-line light curves for the period 1988 to 2008.Comment: 11 pages, 5 figures, 6 tables. Accepted for publication in Ap
Patients with diffuse idiopathic skeletal hyperostosis do not have increased peripheral bone mineral density and geometry
Objectives. Recent studies have suggested that areal BMD (aBMD) measured by DXA is elevated in patients with DISH. We used peripheral QCT (pQCT) to assess volumetric BMD (vBMD) and bone geometry of the radius, tibia and the third metacarpal bone. Methods. Patients with established DISH and a control group of healthy individuals were recruited. pQCT measurements were performed at the distal epiphyses and mid-shafts of the radius, the tibia and the third metacarpal bone. At the epiphyses cross-sectional area (CSA), total BMD and trabecular BMD were measured. At the shafts, total bone CSA, cortical CSA, cortical wall thickness and cortical BMD were determined. In addition, muscle and fat CSA of the forearm and lower leg were assessed. Bone parameters were compared between the two groups using independent t-tests. Results. Thirty DISH patients and 30 controls comparable with regard to age and height were included in this study. None of the measured bone parameters differed between groups. Conclusions. In contrast to suggestions based on DXA, pQCT revealed that DISH patients do not have increased vBMD and bone geometry in the appendicular skeleton. Ossification at tendon or ligament insertion sites may lead to overestimation of aBMD if assessed by DX
Water footprint of protein yield of field crop species based on evapotranspiration patterns
Water availability is one of the major physiological factors influencing plant growth and development. An assessment study has been done at the Szent István University, Gödöllő to evaluate and identify the water footprint of protein yield of field crop species.
Six field crop species (sugar beet Beta vulgaris, winter barley Hordeum vulgare, winter wheat Triticum aestivum, maize Zea mays, potato Solanum tuberosum, and alfalfa Medicago sativa) were involved in the study. Evapotranspiration patterns of the crops studied have been identified and physiologically reliable protein ranges within crop yields were evaluated.
The results obtained suggest, that water footprint of cereals proved to be the lowest, however maize values were highly affected by the high variability of protein yield. Alfalfa, potato and sugar beet water footprints were in accordance with their evapotranspiration patterns.
 
Transparent metal electrodes from ordered nanosphere arrays
We show that perforated metal electrode arrays, fabricated using nanosphere
lithography, provide a viable alternative to conductive metal oxides as
transparent electrode materials. The inter-aperture spacing is tuned by
varying etching times in an oxygen plasma, and the effect of inter-aperture
“wire” thickness on the optical and electronic properties of perforated silver
films is shown. Optical transmission is limited by reflection and surface
plasmons, and for these results do not exceed 73%. Electrical sheet resistance
is shown to be as low as 3 Ω ◻−1 for thermally evaporated silver films. The
performance of organic photovoltaic devices comprised of a P3HT:PCBM bulk
heterojunction deposited onto perforated metal arrays is shown to be limited
by optical transmission, and a simple model is presented to overcome these
limitations
Appendectomy in the surgical treatment of benign ovarian mucinous cystadenomas — is it necessary?
Objectives: To determine if appendectomy as an adjunctive procedure is necessary in the surgical treatment of benign ovarian mucinous cystadenomas.
Material and methods: Retrospective analysis of clinical data: in a research hospital, obstetrics and gynecology department setting, 63 cases of benign ovarian mucinous cystadenomas confirmed in the pathological evaluation were revised. 59 had the complete clinical, final pathological and follow-up data available and were included.
Results: 20.6% (13/59) went through an appendectomy. Basic characteristics of patients with different appendiceal pathologies did not show any significant differences. In the study group the mean age, parity, adnexial mass size were (40.1 ± 12.4); (1.3 ± 1.1) and (9.1 ± 5.3 cm), respectively. Patients were either operated laparoscopically (20), laparotomically (39) to perform a unilateral salpingoopherectomy/cystectomy. In 7 patients, oopherectomy was an additional procedure with: 2 abdominal hysterectomies, 4 cesarean sections and 1 total laparoscopic hysterectomy. 2 synchronous appendiceal pathologies (mucinous cystadenomas of the appendix) were defined in appendectomies performed. In these cases, the ovarian tumour sizes were: 7 cm and 4 cm.
Conclusions: In the presence of a benign or borderline unilateral ovarian mucinous tumour as defined during the operation and especially if it is larger than 10–12 cm and with normal peritoneal and appendiceal gross morphology, appendectomy is not a necessary adjunctive procedure
Characterization of deposits formed on diesel injectors in field test and from thermal oxidative degradation of n-hexadecane in a laboratory reactor
Solid deposits from commercially available high-pressure diesel injectors (HPDI) were analyzed to study the solid deposition from diesel fuel during engine operation. The structural and chemical properties of injector deposits were compared to those formed from the thermal oxidative stressing of a diesel fuel range model compound, n-hexadecane at 160°C and 450 psi for 2.5 h in a flow reactor. Both deposits consist of polyaromatic compounds (PAH) with oxygen moieties. The similarities in structure and composition of the injector deposits and n-hexadecane deposits suggest that laboratory experiments can simulate thermal oxidative degradation of diesel in commercial injectors. The formation of PAH from n-hexadecane showed that aromatization of straight chain alkanes and polycondensation of aromatic rings was possible at temperatures as low as 160°C in the presence of oxygen. A mechanism for an oxygen-assisted aromatization of cylcoalkanes is proposed
Nuclear Repulsion Enables Division Autonomy in a Single Cytoplasm
SummaryBackgroundCurrent models of cell-cycle control, based on classic studies of fused cells, predict that nuclei in a shared cytoplasm respond to the same CDK activities to undergo synchronous cycling. However, synchrony is rarely observed in naturally occurring syncytia, such as the multinucleate fungus Ashbya gossypii. In this system, nuclei divide asynchronously, raising the question of how nuclear timing differences are maintained despite sharing a common milieu.ResultsWe observe that neighboring nuclei are highly variable in division-cycle duration and that neighbors repel one another to space apart and demarcate their own cytoplasmic territories. The size of these territories increases as a nucleus approaches mitosis and can influence cycling rates. This nonrandom nuclear spacing is regulated by microtubules and is required for nuclear asynchrony, as nuclei that transiently come in very close proximity will partially synchronize. Sister nuclei born of the same mitosis are generally not persistent neighbors over their lifetimes yet remarkably retain similar division cycle times. This indicates that nuclei carry a memory of their birth state that influences their division timing and supports that nuclei subdivide a common cytosol into functionally distinct yet mobile compartments.ConclusionsThese findings support that nuclei use cytoplasmic microtubules to establish “cells within cells.” Individual compartments appear to push against one another to compete for cytoplasmic territory and insulate the division cycle. This provides a mechanism by which syncytial nuclei can spatially organize cell-cycle signaling and suggests size control can act in a system without physical boundaries
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