128 research outputs found
Traditional healers and the treatment of sexually transmitted illness in rural
Abstract Lately there has been increasing interest regarding the practice of traditional healers and their use of indigenous plants to treat illnesses. Twenty-three local healers (n'ganga) in Chiawa, rural Zambia, were interviewed about knowledge, practices, and their use of indigenous plants in the diagnosis and treatment of sexually transmitted illnesses (STIs) among male clients. They were also asked about their perceptions of modern medicine. The study revealed that all the n'ganga diagnosed and treated three main types of STIs. They named them as: songeya, doroba and bola-bola. They treated the illnesses with Strychnos cocculoides; Musa species; Solanum delegoense; Ximenia caffra; Diplorynchus condylocarpon; and Croton megalobotrys. Ten of the n'ganga perceived modern medicine to be effective against STIs and five of them sometimes referred some of the clients to the local health centre. It is being argued that a scheme to incorporate the n'ganga into STD control activities in which they can be utilised to refer clients to modern medical facilities can be baneficial. Given the necessary health information and support, the n'ganga may effectively execute this scheme
T-Cell Receptor/CD28-Mediated Activation of Human T Lymphocytes Induces Expression of Functional -Opioid Receptors
ABSTRACT Opiates function as immunomodulators, partly by their effects on T cells. Opioids act via -, âŠ-, and -opioid receptors, among which the -type is of particular interest, because morphine-like opioids preferentially bind to it. Here we report that -opioid receptor mRNA was induced after CD3/28-mediated activation of primary human T lymphocytes and Jurkat T cells, neither of which expresses the gene constitutively. Moreover, a reporter gene construct containing 2624 base pairs of the -opioid receptor promoter was transactivated by CD3/28 stimulation. Transcriptional induction of the -opioid receptor gene was mediated by activator protein-1 (AP-1), nuclear factor-B, and nuclear factor of activated T cells (NFAT). NFAT was found to bind to three sequences of the -opioid receptor promoter, located at nucleotides ÏȘ1064, ÏȘ785, and ÏȘ486. Although the ÏȘ486 element is in close proximity to a putative AP-1 site, there was no evidence for a combined AP-1/NFAT site. Furthermore, we demonstrated that the induction of interleukin-2 mRNA and protein in activated T cells was inhibited by morphine in cells, in which -opioid receptors had been induced by CD3/28 monoclonal antibodies (mAbs), and that this effect was blocked by the -opioid receptor-specific antagonist D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH 2 . CD3/28 mAb-induced interleukin-2 transcription was also inhibited by the opioids fentanyl and loperamide. This indicates that the induced -opioid receptor mRNA is translated into functional receptor protein. Furthermore, a -opioid receptor-enhanced green fluorescent protein-fusion protein was localized in membranes of Jurkat cells and internalized in response to [D-Ala 2 ,NMe-Phe 4 ,Gly 5 -ol]-enkephalin but not morphine. In conclusion, these data emphasize the role of opioids in the modulation of T lymphocyte signaling
Growth cone responses to growth and chemotropic factors
Abstract During nervous system development axons reach their target areas under the influence of numerous guidance cues that affect rate and direction of growth. This report addresses the unsettled question of whether and to what extent growth velocity and turning responses (attraction, repulsion) are interdependent. We exposed individual growth cones of fetal rat dorsal root ganglion neurons in culture asymmetrically to gradients of seven different factors and recorded their growth rates and turning angles. Growth cones exhibited divergent patterns of turning and growth responses. For example, hepatocyte growth factor (HGF), insulin-like growth factor-1 (IGF-1) and thrombin all promoted growth, but HGF was a powerful attractant, thrombin a potent repellent and IGF-1 did not elicit turning. Galanin and neuropeptide Y also affected growth and â or turning differentially. Finally, nerve growth factor in the culture medium not only inhibited the turning responses to HGF, but also converted growth promotion of HGF and IGF-1 into inhibition. Overall, our studies indicate that: (i) turning and advance are regulated independently, except that strong attractive or repulsive responses generally are accompanied by growth promotion; (ii) asymmetric growth factor application per se does not elicit attraction; (iii) regulation of the two parameters may occur through a single receptor; and (iv) the effects of combined growth factors may not be additive and can be inhibitory
Time-Resolved Coherent Photoelectron Spectroscopy of Quantized Electronic States on Metal Surfaces
Time-resolved two-photon photoemission in combination with the coherent excitation of several quantum states was used to study the ultrafast electron dynamics of imagepotential states on metal surfaces. For a (100) surface of copper, the spectroscopy of quantum beats made previously unresolved high-order states (quantum number n Ő 4) experimentally accessible. By exciting electrons close to the vacuum level, electron wave packets could be created and detected that described the quasi-classical periodic motion of weakly bound electrons. They traveled more than 200 Ă
away from the surface and oscillated back and forth with a period of 800 femtoseconds. Photoelectron spectroscopy has developed into one of the most versatile and successful tools for surface studies. Particularly attractive features of this technique are the high surface sensitivity associated with the low escape depth of the photoelectrons and the capability of angle-resolved photoemission to completely characterize electronic states in energy and momentum space (1). Recently, these features have been combined with ultrafast laser excitation for direct time-domain investigations of electron dynamics at surfaces (2). Here, we demonstrate another facet of this powerful technique, the investigation of coherence phenomena in real time. In contrast to experimental methods that rely merely on intensities, coherent spectroscopies offer the unique capability of accessing not only the amplitudes but also the phases of the wave functions of interest (3). This technique dramatically increases the amount of information that one is able to obtain about the temporal evolution of fast processes. In this report, we discuss the dynamics of image-potential states, that is, the quantized excited states of electrons that exist in front of many metal surfaces (4, 5). Using femtosecond time-resolved two-photon photoemission (2PPE), we observed the interference between the wave functions of neighboring eigenstates and the quasi-classical motion of electron wave packets created by the coherent superposition of several quantum states. Recently, the imaging of the static charge density of related surface electronic (ground) states in real space with the scanning tunneling microscope has attracted considerable interest (6); the present results reveal the dynamical evolution of excited electrons in real time. Image-potential states are conceptually rather simple. An electron at a distance z in front of a conducting metal surface experiences an attractive force F(z) Ï ÏȘe 2 /(2z) 2 identical to that produced by a positive (mirror image) charge at a distance z inside the metal converging toward the vacuum energy, where the influence of the surface potential on the binding energy E B Ï ÏȘE n is approximated by a quantum defect 0 Ő
a Ő
0.5. Experimentally, image-potential states have been studied with 2PPE on many metal surfaces including surfaces covered with adsorbates and metallic overlayers (5, 7-11). One photon with energy á a (á is Planck's constant h divided by 2 and is the photon frequency times 2) excites an electron out of an occupied state below the Fermi energy E F into the image-potential state n. A second photon with energy á b excites the electron to an energy above E vac The experimental setup consisted of a 80-MHz Ti:sapphire laser system that generated infrared (IR) pulses of 70-fs duration. Frequency-tripled 95-fs ultraviolet (UV) pulses from this laser were used for the excitation step (á a Ï 4.7 eV). The photoelectrons were emitted by the fundamental IR pulses (á b Ï 1.57 eV) and were detected in a hemispherical analyzer with an energy resolution of 30 meV and an angular acceptance of Ïź0.6°about the surface normal. The preparation of the Cu(111) and Cu(100) samples and details of the ultrahigh-vacuum chamber have been described elsewhere (5). The samples were kept at room temperature. Typical energy-resolved 2PPE spectra of C
Accretion Disc Theory: From the Standard Model Until Advection
Accretion disc theory was first developed as a theory with the local heat
balance, where the whole energy produced by a viscous heating was emitted to
the sides of the disc. One of the most important new invention of this theory
was a phenomenological treatment of the turbulent viscosity, known as ''alpha''
prescription, when the (r) component of the stress tensor was
approximated by ( P) with a unknown constant . This
prescription played the role in the accretion disc theory as well important as
the mixing-length theory of convection for stellar evolution. Sources of
turbulence in the accretion disc are discussed, including nonlinear
hydrodynamical turbulence, convection and magnetic field role. In parallel to
the optically thick geometrically thin accretion disc models, a new branch of
the optically thin accretion disc models was discovered, with a larger
thickness for the same total luminosity. The choice between these solutions
should be done of the base of a stability analysis. The ideas underlying the
necessity to include advection into the accretion disc theory are presented and
first models with advection are reviewed. The present status of the solution
for a low-luminous optically thin accretion disc model with advection is
discussed and the limits for an advection dominated accretion flows (ADAF)
imposed by the presence of magnetic field are analysed.Comment: Roceeding of the Int. Workshop "Observational Evidence for Black
Holes in the Universe". Calcutta, 11-17 January 1998. Kluwer Acad. Pu
Cost effectiveness of stapled haemorrhoidopexy and traditional excisional surgery for the treatment of haemorrhoidal disease
Objective
Our objective was to compare the cost effectiveness of stapled haemorrhoidopexy (SH) and traditional haemorrhoidectomy (TH) in the treatment of grade IIâIV haemorrhoidal disease from the perspective of the UK national health service.
Methods
An economic evaluation was conducted alongside an open, two-arm, parallel-group, pragmatic, multicentre, randomised controlled trial conducted in several hospitals in the UK. Patients were randomised into either SH or TH surgery between January 2011 and August 2014 and were followed up for 24 months. Intervention and subsequent resource use data were collected using case review forms and questionnaires. Benefits were collected using the EQ-5D-3L (EuroQoLâfive dimensionsâthree levels) instrument. The primary economic outcome was incremental cost measured in pounds (ÂŁ), year 2016 values, relative to the incremental benefit, which was estimated using quality-adjusted life-years (QALYs). Cost and benefits accrued in the second year were discounted at 3.5%. The base-case analysis was based on imputed data. Uncertainty was explored using univariate sensitivity analyses.
Results
Participants (n = 777) were randomised to SH (n = 389) or TH (n = 388). The mean cost of SH was ÂŁ337 (95% confidence interval [CI] 251â423) higher than that of TH and the mean QALYs were â0.070 (95% CI â0.127 to â0.011) lower than for TH. The base-case cost-utility analysis indicated that SH has zero probability of being cost effective at both the ÂŁ20,000 and the ÂŁ30,000 threshold. Results from the sensitivity analyses were similar to those from the base-case analysis.
Conclusions
The evidence suggests that, on average, the total mean costs over the 24-month follow-up period were significantly higher for the SH arm than for the TH arm. The QALYs were also, on average, significantly lower for the SH arm. These results were supported by the sensitivity analyses. Therefore, in terms of cost effectiveness, TH is a superior surgical treatment for the management of grade IIâIV haemorrhoids when compared with SH
Polycomb enables primitive endoderm lineage priming in embryonic stem cells
Abstract Mouse embryonic stem cells (ESCs), like the blastocyst from which they are derived, contain precursors of the epiblast (Epi) and primitive endoderm (PrEn) lineages. While transient in vivo, these precursor populations readily interconvert in vitro. We show that altered transcription is the driver of these coordinated changes, known as lineage priming, in a process that exploits novel polycomb activities. We find that intragenic levels of the polycomb mark H3K27me3 anti-correlate with changes in transcription, irrespective of the gene's developmental trajectory or identity as a polycomb target. In contrast, promoter proximal H3K27me3 is markedly higher for PrEn priming genes. Consequently, depletion of this modification stimulates the degree to which ESCs are primed towards PrEn when challenged to differentiate, but has little effect on gene expression in self-renewing ESC culture. These observations link polycomb with dynamic changes in transcription and stalled lineage commitment, allowing cells to explore alternative choices prior to a definitive decision
LOFAR Sparse Image Reconstruction
Context. The LOw Frequency ARray (LOFAR) radio telescope is a giant digital
phased array interferometer with multiple antennas distributed in Europe. It
provides discrete sets of Fourier components of the sky brightness. Recovering
the original brightness distribution with aperture synthesis forms an inverse
problem that can be solved by various deconvolution and minimization methods
Aims. Recent papers have established a clear link between the discrete nature
of radio interferometry measurement and the "compressed sensing" (CS) theory,
which supports sparse reconstruction methods to form an image from the measured
visibilities. Empowered by proximal theory, CS offers a sound framework for
efficient global minimization and sparse data representation using fast
algorithms. Combined with instrumental direction-dependent effects (DDE) in the
scope of a real instrument, we developed and validated a new method based on
this framework Methods. We implemented a sparse reconstruction method in the
standard LOFAR imaging tool and compared the photometric and resolution
performance of this new imager with that of CLEAN-based methods (CLEAN and
MS-CLEAN) with simulated and real LOFAR data Results. We show that i) sparse
reconstruction performs as well as CLEAN in recovering the flux of point
sources; ii) performs much better on extended objects (the root mean square
error is reduced by a factor of up to 10); and iii) provides a solution with an
effective angular resolution 2-3 times better than the CLEAN images.
Conclusions. Sparse recovery gives a correct photometry on high dynamic and
wide-field images and improved realistic structures of extended sources (of
simulated and real LOFAR datasets). This sparse reconstruction method is
compatible with modern interferometric imagers that handle DDE corrections (A-
and W-projections) required for current and future instruments such as LOFAR
and SKAComment: Published in A&A, 19 pages, 9 figure
Early intervention in 208 Swedish preschoolers with autism spectrum disorder
A B S T R A C T Early intervention has been reported to improve outcome in children with autism spectrum disorders (ASDs). Several studies in the field have been randomized controlled trials (RCTs). The aim of this study was to assess ASD outcome in a large naturalistic study. Two hundred and eight children, aged 20-54 months, with a clinical diagnosis of ASD were given intervention and monitored prospectively in a naturalistic fashion over a period of 2 years. The toddlers were considered representative of all but the most severely multiple disabled preschool children with ASD in Stockholm county. They fell into three cognitive subgroups: one with learning disability, one with developmental delay, and one with normal intellectual functioning. Data on intervention type and intensity were gathered prospectively in a systematic fashion. Intervention was classified into intensive applied behaviour analysis (ABA) and non-intensive, targeted interventions, also based on ABA principles. Children were comprehensively assessed by a research team before the onset of intervention, and then, again, 2 years later. Change in Vineland adaptive behaviour scales composite scores from intake (T1) to leaving the study (T2) was set as the primary outcome variable. The research team remained blind to the type and intensity of interventions provided. One hundred and ninety-eight (95%) of the original samples stayed in the study throughout the whole 2-year period and 192 children had a complete Vineland composite score results both at T1 and T2. Vineland composite scores increased over the 2-year period. This increase was accounted for by the subgroup with normal cognitive functioning. There was no significant difference between the intensive and nonintensive groups. Individual variation was considerable, but no child in the study was ''problem-free'' at follow-up. Our data do not support that children with ASD generally benefit more from the most intensive ABA intervention programs than from less intensive interventions or targeted interventions based on ABA.
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