546 research outputs found
Hypobranching Induced by Both Environmental Antioxidants and ROS Metabolism Gene Knockouts in Neurospora Crassa
Previous work suggested a role of reactive oxygen species (ROS) metabolism on branch density, the statistical distribution of physical distances between branch points along a growing hypha in Neurospora. Here we report the results of experiments designed to ask more generally about the relationship between ROS and branch density by examining the branching effects of selected ROS metabolism gene knockout mutants as well as the impact on branching of exogenously added antioxidants. In all ROS metabolism mutants tested, growth was shown to branch less densely (hypobranching) when grown at lower temperatures, a shift not observed in the wild-type. Interestingly, this holds true for knockouts of genes expected to reduce ROS as well as those expected to produce them. In addition, in tests on wild type Neurospora, added ascorbic acid produced unusual branching patterns. Hypha exposed to exogenous antioxidants display dose dependent hypobranching with hypha becoming more hypobranched as doses increase. At higher doses, however, the branch distribution becomes bimodal with one maximum continuing to shift toward hypobranching and the second maximum representing a spike of very closely spaced branch points
Modulation of the myogenic mechanism: concordant effects of NO synthesis inhibition and O 2 − dismutation on renal autoregulation in the time and frequency domains
Renal blood flow autoregulation was investigated in anesthetized C57Bl6 mice using time- and frequency-domain analyses. Autoregulation was reestablished by 15 s in two stages after a 25-mmHg step increase in renal perfusion pressure (RPP). The renal vascular resistance (RVR) response did not include a contribution from the macula densa tubuloglomerular feedback mechanism. Inhibition of nitric oxide (NO) synthase [NG-nitro-l-arginine methyl ester (l-NAME)] reduced the time for complete autoregulation to 2 s and induced 0.25-Hz oscillations in RVR. Quenching of superoxide (SOD mimetic tempol) during l-NAME normalized the speed and strength of stage 1 of the RVR increase and abolished oscillations. The slope of stage 2 was unaffected by l-NAME or tempol. These effects of l-NAME and tempol were evaluated in the frequency domain during random fluctuations in RPP. NO synthase inhibition amplified the resonance peak in admittance gain at 0.25 Hz and markedly increased the gain slope at the upper myogenic frequency range (0.06–0.25 Hz, identified as stage 1), with reversal by tempol. The slope of admittance gain in the lower half of the myogenic frequency range (equated with stage 2) was not affected by l-NAME or tempol. Our data show that the myogenic mechanism alone can achieve complete renal blood flow autoregulation in the mouse kidney following a step increase in RPP. They suggest also that the principal inhibitory action of NO is quenching of superoxide, which otherwise potentiates dynamic components of the myogenic constriction in vivo. This primarily involves the first stage of a two-stage myogenic response
Outcomes and safety of concomitant nevirapine and rifampicin treatment under programme conditions in Malawi.
SETTING: Thyolo District Hospital, rural Malawi. OBJECTIVES: To report on 1) clinical, immunological and virological outcomes and 2) safety among human immunodeficiency virus (HIV) infected patients with tuberculosis (TB) who received concurrent nevirapine (NVP) and rifampicin (RMP) based treatment. DESIGN: Retrospective cohort study. METHODS: Analysis of programme data, June-December 2007. RESULTS: Of a total of 156 HIV-infected TB patients who started NVP-based antiretroviral treatment, 136 (87%) completed TB treatment successfully, 16 (10%) died and 5 (4%) were transferred out. Mean body weight and CD4 gain (adults) were respectively 4.4 kg (95%CI 3.3-5.4) and 140 cells/mm(3) (95%CI 117-162). Seventy-four per cent of patients who completed TB treatment and had a viral load performed (n = 74) had undetectable levels (<50 copies/ml), while 17 (22%) had a viral load of 50-1000 copies/ml. Hepatotoxicity was present in 2 (1.3%) patients at baseline. Two patients developed Grade 2 and one developed Grade 3 alanine transaminase enzyme elevations during TB treatment (incidence rate per 10 years of follow-up 4.2, 95%CI 1.4-13.1). There were no reported deaths linked to hepatotoxicity. CONCLUSIONS: In a rural district in Malawi, concomitant NVP and RMP treatment is associated with good TB treatment outcomes and appears safe. Further follow-up of patients would be useful to ascertain the longer-term effects of this concurrent treatment
The published research paper: is it an important indicator of successful operational research at programme level?
Is a published research paper an important indicator of successful operational research at programme level in low-income countries? In academia, publishing in peer-reviewed scientific journals is highly encouraged and strongly pursued for academic recognition and career progression. In contrast, for those who engage in operational research at programme level, there is often no necessity or reward for publishing the results of research studies; it may even be criticized as being an unnecessary detraction from programme-related work. We present arguments to support publishing operational research from low-income countries; we highlight some of the main reasons for failure of publication at programme level and suggest ways forward
Relativistic stars with purely toroidal magnetic fields
We investigate the effects of the purely toroidal magnetic field on the
equilibrium structures of the relativistic stars. The master equations for
obtaining equilibrium solutions of relativistic rotating stars containing
purely toroidal magnetic fields are derived for the first time. To solve these
master equations numerically, we extend the Cook-Shapiro-Teukolsky scheme for
calculating relativistic rotating stars containing no magnetic field to
incorporate the effects of the purely toroidal magnetic fields. By using the
numerical scheme, we then calculate a large number of the equilibrium
configurations for a particular distribution of the magnetic field in order to
explore the equilibrium properties. We also construct the equilibrium sequences
of the constant baryon mass and/or the constant magnetic flux, which model the
evolution of an isolated neutron star as it loses angular momentum via the
gravitational waves. Important properties of the equilibrium configurations of
the magnetized stars obtained in this study are summarized as follows ; (1) For
the non-rotating stars, the matter distribution of the stars is prolately
distorted due to the toroidal magnetic fields. (2) For the rapidly rotating
stars, the shape of the stellar surface becomes oblate because of the
centrifugal force. But, the matter distribution deep inside the star is
sufficiently prolate for the mean matter distribution of the star to be
prolate. (3) The stronger toroidal magnetic fields lead to the mass-shedding of
the stars at the lower angular velocity. (4) For some equilibrium sequences of
the constant baryon mass and magnetic flux, the stars can spin up as they lose
angular momentum.Comment: 13 figures, 7 tables, submitted to PR
Трансплантация почки у пациентки с семейной средиземноморской лихорадкой, осложненной вторичным амилоидозом (клинический случай)
The paper presents a clinical case of successful kidney transplantation (KTx) in a patient with end-stage chronic kidney disease (ESKD) resulting from familial Mediterranean fever (FMF). Pre-transplant preparation and posttransplant management tactics are presented. The authors conclude that ESKD can be effectively treated by KTx in a patient with FMF against the background of ongoing pathogenetic therapy in autoinflammation.В статье представлен клинический случай успешной трансплантации почки у пациентки с терминальной стадией хронической болезни почек в исходе семейной средиземноморской лихорадки. Представлена тактика предтрансплантационной подготовки и посттрансплантационного ведения. Авторы приходят к выводу об эффективности лечения терминальной почечной недостаточности методом трансплантации почки у больной с семейной средиземноморской лихорадкой на фоне продолжающейся патогенетической терапии аутовоспаления
Performance of pilot-scale microbial fuel cells treating wastewater with associated bioenergy production in the Caribbean context
Microbial fuel cell (MFC) technology represents a form of renewable energy that generates bioelectricity from what would otherwise be considered a waste stream. MFCs may be ideally suited to the small island developing state (SIDS) context, such as Trinidad and Tobago where seawater as the main electrolyte is readily available and economical renewable and sustainable electricity is also deemed a priority. Hence this project tested two identical laboratory-scaled MFC systems that were specifically designed and developed for the Caribbean regional context. They consisted of two separate chambers, an anaerobic anodic chamber inoculated with wastewater and an aerobic cathodic chamber separated by a proton exchange membrane. Domestic wastewater from two various wastewater treatment plants inflow (after screening) was placed into the anodic chamber, and seawater from the Atlantic Ocean and Gulf of Paria placed into the cathodic chambers respectively with the bacteria present in the wastewater attaching to the anode. Experimental results demonstrated that the bacterial degradation of the wastewaters as substrate induced an electron flow through the electrodes producing bioelectricity whilst simultaneously reducing the organic matter as biochemical oxygen demand and chemical oxygen demand by 30 to 75%. The average bioenergy output for both systems was 84 mW/m² and 96 mW/m² respectively. This study demonstrated the potential for simultaneous bioenergy production and wastewater treatment in the SIDS context
Are HIV-positive presumptive tuberculosis patients without tuberculosis getting the care they need in Zimbabwe?
SETTING: Emakhandeni Clinic provides decentralised and integrated tuberculosis (TB) and human immunodeficiency virus (HIV) care in Bulawayo, Zimbabwe. OBJECTIVES: To compare HIV care for presumptive TB patients with and without TB registered in 2013. DESIGN: Retrospective cohort study using routine programme data. RESULTS: Of 422 registered presumptive TB patients, 26% were already known to be HIV-positive. Among the remaining 315 patients, 255 (81%) were tested for HIV, of whom 190 (75%) tested HIV-positive. Of these, 26% were diagnosed with TB and 71% without TB (3% had no TB result recorded). For the 134 patients without TB, antiretroviral treatment (ART) eligibility data were recorded for 42 (31%); 95% of these were ART eligible. Initiation of cotrimoxazole preventive therapy (CPT) and ART was recorded for respectively 88% and 90% of HIV-positive patients with TB compared with respectively 40% and 38% of HIV-positive patients without TB (P < 0.001). CONCLUSION: Presumptive TB patients without TB had a high HIV positivity rate and, for those with available data, most were ART eligible. Unlike HIV-positive patients diagnosed with TB, CPT and ART uptake for these patients was poor. A 'test and treat' approach and better service linkages could be life-saving for these patients, especially in southern Africa, where there are high burdens of HIV and TB
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