317 research outputs found
About Trypanosoma brucei gambiense, the causative agent of the chronic form of Human African Trypanosomiasis: some findings and proposals
Since its discovery at the beginning of 20th century, Human African Trypanosomiasis or sleeping sickness has killed several hundred thousands of individuals in Africa, mainly in Central part of the continent. The actual situation of the disease in several countries is dramatic, such as in Sudan, Democratic Republic of Congo or Angola. However, diagnosis is still based on the detection of parasites in blood or lymphatic juice by microscopy, like in 1930's. Furthermore, since the discovery of melarsoprol in 1949, no novel drugs have been synthesized for treatment. This must consider it within the whole context of "most-neglected diseases" but some findings obtained through biotechnology are discussed in terms of epidemiology and control applications.
Key words: Human African Trypanosomiasis, neglected disease, biotechnologies.
African Journal of Biotechnology Vol. 2 (12), pp. 657-661, December 200
The use of Multiple Displacement Amplification to increase the detection and genotyping of <i>Trypanosoma</i> samples immobilised on FTA filters.
Whole genome amplification methods are a recently developed tool for amplifying DNA from limited template. We report its application in trypanosome infections, characterized by low parasitemias. Multiple displacement amplification (MDA) amplifies DNA with a simple in vitro step and was evaluated on mouse blood samples on FTA filter cards with known numbers of Trypanosoma brucei parasites. The data showed a 20-fold increase in the number of PCRs possible per sample, using primers diagnostic for the multicopy ribosomal ITS region or 177-bp repeats, and a 20-fold increase in sensitivity over nested PCR against a single-copy microsatellite. Using MDA for microsatellite genotyping caused allele dropout at low DNA concentrations, which was overcome by pooling multiple MDA reactions. The validity of using MDA was established with samples from Human African Trypanosomiasis patients. The use of MDA allows maximal use of finite DNA samples and may prove a valuable tool in studies where multiple reactions are necessary, such as population genetic analyses
Weyl asymptotics for magnetic Schr\"odinger operators and de Gennes' boundary condition
This paper is concerned with the discrete spectrum of the self-adjoint
realization of the semi-classical Schr\"odinger operator with constant magnetic
field and associated with the de Gennes (Fourier/Robin) boundary condition. We
derive an asymptotic expansion of the number of eigenvalues below the essential
spectrum (Weyl-type asymptotics). The methods of proof relies on results
concerning the asymptotic behavior of the first eigenvalue obtained in a
previous work [A. Kachmar, J. Math. Phys. Vol. 47 (7) 072106 (2006)].Comment: 28 pages (revised version). to appear in Rev Math Phy
Revision of the Synechococcales (Cyanobacteria) through recognition of four families including Oculatellaceae fam. nov. and Trichocoleaceae fam. nov. and six new genera containing 14 species
A total of 48 strains of thin, filamentous cyanobacteria in Synechococcales were studied by sequencing 16S rRNA and rpo C1 sequence fragments. We also carefully characterized a subset of these by morphology. Phylogenetic analysis of the 16S rRNA gene data using Bayesian inference of a large Synechococcales alignment (345 OTUâs) was in agreement with the phylogeny based on the rpo C1 gene for 59 OTUâs. Both indicated that the large family-level grouping formerly classified as the Leptolyngbyaceae could be further divided into four family-level clades. Two of these family-level clades have been recognized previously as Leptolyngbyaceae and Prochlorotrichaceae. Oculatellaceae fam. nov. and Trichocoleaceae fam. nov. are proposed for the other two families. The Oculatellaceae was studied in greater detail, and six new genera containing 14 species were characterized and named. These new taxa are: Pegethrix botrychoides , P. olivacea, P. convoluta , P. indistincta , Drouetiella lurida , D. hepatica , D. fasciculata , Cartusia fontana , Tildeniella torsiva , T. nuda , Komarkovaea angustata , Kaiparowitsia implicata , Timaviella obliquedivisa , and T. radians
Adverse drug reactions associated with amitriptyline - protocol for a systematic multiple-indication review and meta-analysis
Background: Unwanted anticholinergic effects are both underestimated and frequently overlooked. Failure to identify adverse drug reactions (ADRs) can lead to prescribing cascades and the unnecessary use of over-thecounter products. The objective of this systematic review and meta-analysis is to explore and quantify the frequency and severity of ADRs associated with amitriptyline vs. placebo in randomized controlled trials (RCTs) involving adults with any indication, as well as healthy individuals. Methods: A systematic search in six electronic databases, forward/backward searches, manual searches, and searches for Food and Drug Administration (FDA) and European Medicines Agency (EMA) approval studies, will be performed. Placebo-controlled RCTs evaluating amitriptyline in any dosage, regardless of indication and without restrictions on the time and language of publication, will be included, as will healthy individuals. Studies of topical amitriptyline, combination therapies, or including <100 participants, will be excluded. Two investigators will screen the studies independently, assess methodological quality, and extract data on design, population, intervention, and outcomes ((non-)anticholinergic ADRs, e.g., symptoms, test results, and adverse drug events (ADEs) such as falls). The primary outcome will be the frequency of anticholinergic ADRs as a binary outcome (absolute number of patients with/without anticholinergic ADRs) in amitriptyline vs. placebo groups. Anticholinergic ADRs will be defined by an experienced clinical pharmacologist, based on literature and data from Martindale: The Complete Drug Reference. Secondary outcomes will be frequency and severity of (non-)anticholinergic ADRs and ADEs. The information will be synthesized in meta-analyses and narratives. We intend to assess heterogeneity using metaregression (for indication, outcome, and time points) and I2 statistics. Binary outcomes will be expressed as odds ratios, and continuous outcomes as standardized mean differences. Effect measures will be provided using 95% confidence intervals. We plan sensitivity analyses to assess methodological quality, outcome reporting etc., and subgroup analyses on age, dosage, and duration of treatment. Discussion: We will quantify the frequency of anticholinergic and other ADRs/ADEs in adults taking amitriptyline for any indication by comparing rates for amitriptyline vs. placebo, hence, preventing bias from disease symptoms and nocebo effects. As no standardized instrument exists to measure it, our overall estimate of anticholinergic ADRs may have limitations
Accuracy of five algorithms to diagnose gambiense human African trypanosomiasis.
Algorithms to diagnose gambiense human African trypanosomiasis (HAT, sleeping sickness) are often complex due to the unsatisfactory sensitivity and/or specificity of available tests, and typically include a screening (serological), confirmation (parasitological) and staging component. There is insufficient evidence on the relative accuracy of these algorithms. This paper presents estimates of the accuracy of five algorithms used by past MĂ©decins Sans FrontiĂšres programmes in the Republic of Congo, Southern Sudan and Uganda
Eigenvalues of Laplacian with constant magnetic field on non-compact hyperbolic surfaces with finite area
We consider a magnetic Laplacian on a
noncompact hyperbolic surface \mM with finite area. is a real one-form
and the magnetic field is constant in each cusp. When the harmonic
component of satifies some quantified condition, the spectrum of
is discrete. In this case we prove that the counting function of
the eigenvalues of satisfies the classical Weyl formula, even
when $dA=0.
Identification of sVSG117 as an immunodiagnostic antigen and evaluation of a dual-antigen lateral flow test for the diagnosis of human african trypanosomiasis
The diagnosis of human African trypanosomiasis (HAT) caused by Trypanosoma brucei gambiense relies mainly on the Card Agglutination Test for Trypanosomiasis (CATT). There is no immunodiagnostic for HAT caused by T. b. rhodesiense. Our principle aim was to develop a prototype lateral flow test that might be an improvement on CATT.Pools of infection and control sera were screened against four different soluble form variant surface glycoproteins (sVSGs) by ELISA and one, sVSG117, showed particularly strong immunoreactivity to pooled infection sera. Using individual sera, sVSG117 was shown to be able to discriminate between T. b. gambiense infection and control sera by both ELISA and lateral flow test. The sVSG117 antigen was subsequently used with a previously described recombinant diagnostic antigen, rISG65, to create a dual-antigen lateral flow test prototype. The latter was used blind in a virtual field trial of 431 randomized infection and control sera from the WHO HAT Specimen Biobank.In the virtual field trial, using two positive antigen bands as the criterion for infection, the sVSG117 and rISG65 dual-antigen lateral flow test prototype showed a sensitivity of 97.3% (95% CI: 93.3 to 99.2) and a specificity of 83.3% (95% CI: 76.4 to 88.9) for the detection of T. b. gambiense infections. The device was not as good for detecting T. b. rhodesiense infections using two positive antigen bands as the criterion for infection, with a sensitivity of 58.9% (95% CI: 44.9 to 71.9) and specificity of 97.3% (95% CI: 90.7 to 99.7). However, using one or both positive antigen band(s) as the criterion for T. b. rhodesiense infection improved the sensitivity to 83.9% (95% CI: 71.7 to 92.4) with a specificity of 85.3% (95% CI: 75.3 to 92.4). These results encourage further development of the dual-antigen device for clinical use
Effects of salinity and alkalinity on growth and survival of all-male giant freshwater prawn (Macrobrachium rosenbergii De Man, 1879) juveniles
All-male giant freshwater prawns (AMGFPs) have been a popular crop cultivated in the Mekong Delta, Vietnam, due to their proven production efficiency compared to all-female or mixed-sex prawn cultures. However, the crucial water quality factors impacting AMGFP aquaculture efficiency have yet to be elaborately investigated. Two separate experiments were randomly arranged with three replicates to evaluate the effects of salinity or alkalinity on the growth and survival of AMGFP juveniles during the grow-out period. The results show that the prawn survival rate in the salinity range of 0â15â° varied from 66.1 to 74.8ïŒ
and in a salinity range of 0â5â° was relatively low compared to the range of 10-15â°; however, the difference was not significant among salinities after 90 days of culture (p > 0.05). All the prawn growth performance parameters significantly decreased with increasing salinities of 0, 5, 10, and 15â° after 30, 60, and 90 days of culture (p 0.05), and both were significantly higher than those at salinities of 10 and 15â° (p < 0.05) after 90 days of culture. In addition, the survival rate reached 82.5â84.4ïŒ
and did not significantly differ among alkalinities of 80, 100, 120, 140, and 160 mgCaCO3 Lâ1. However, the growth performance parameters and yield of AMGFPs at an alkalinity of 160 mg Lâ1 were significantly higher than those at lower alkalinities (80, 100, 120, and 140 mg CaCO3 Lâ1) after 90 days of culture. Therefore, it is recommended that a salinity range of 0â5â° and alkalinity of 160 mgCaCO3 Lâ1 is optimal for the growth-out culture of AMGFP juveniles
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