585 research outputs found
Identification of circulating parasite antigen in patients with bancroftian filariasis
Because many cases of lymphatic filariasis cannot be diagnosed either clinically or by
immunodiagnostic test based on antibody detection, recent efforts have been more
directed towards developing methods for detecting parasite antigen in the blood or urine.
Using a solid phase (Sepharose 4B) two-site immunoradiometric assay (IRMA)
employing hyperimmune rabbit antifilarial antisera, we have previously shown (Hamilton
et al., 1984) that essentially all cases ofpatent (ie. microfilaremic) infection in patients with
bancroftian filariasis can be detected by this semi-quantitative assay as well as some
individuals with amicrofilaremic (i.e., 'cryptic') infection. The present communication
reports the results of studies that identify a prominent circulating antigen detected by this
IRMA in sera from patients with microfilaremia. The antigen was eluted from Sepharosebound
rabbit polyclonal antiserum that had been reacted with known antigen positive
sera. It was run in SDS-PAGE, blotted to nitrocellulose paper and identified autoradiographically
using '25l-labelled rabbit antifilarial antiserum. Its high molecular weight
(- 200 kD), stability to acid and boiling, and sensitivity to pronase and periodate suggest
its being a glycoprotein. Isolation of this antigen will permit the development of specific
reagents (such as monoclonal antibodies) which should enhance both the sensitivity and
utility of the currently available antigen detection systems
Ultracoherence and Canonical Transformations
The (in)finite dimensional symplectic group of homogeneous canonical
transformations is represented on the bosonic Fock space by the action of the
group on the ultracoherent vectors, which are generalizations of the coherent
states.Comment: 24 page
Site-specific incorporation of phosphotyrosine using an expanded genetic code.
Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active phosphotyrosine-containing proteins by genetically encoding a stable phosphotyrosine analog that is convertible to native phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination
The Emerging Story of Disability Associated with Lymphatic Filariasis: A Critical Review
Globally, 40 million people live with the chronic effects of lymphatic filariasis (LF), making it the second leading cause of disability in the world. Despite this, there is limited research into the experiences of people living with the disease. This review summarises the research on the experiences of people living with LF disability. The review highlights the widespread social stigma and oppressive psychological issues that face most people living with LF-related disability. Physical manifestations of LF make daily activities and participation in community life difficult. The findings confirm the need for the Global Programme to Eliminate Lymphatic Filariasis (GPELF) to support morbidity management activities that address the complex biopsychosocial issues that people living with LF-related disability face
Localizing transcripts to single cells suggests an important role of uncultured deltaproteobacteria in the termite gut hydrogen economy
Identifying microbes responsible for particular environmental
functions is challenging, given that most environments contain
an uncultivated microbial diversity. Here we combined approaches
to identify bacteria expressing genes relevant to catabolite flow
and to locate these genes within their environment, in this case
the gut of a “lower,” wood-feeding termite. First, environmental
transcriptomics revealed that 2 of the 23 formate dehydrogenase
(FDH) genes known in the system accounted for slightly more than
one-half of environmental transcripts. FDH is an essential enzyme
of H_2 metabolism that is ultimately important for the assimilation
of lignocellulose-derived energy by the insect. Second, single-cell
PCR analysis revealed that two different bacterial types expressed
these two transcripts. The most commonly transcribed FDH in situ
is encoded by a previously unappreciated deltaproteobacterium,
whereas the other FDH is spirochetal. Third, PCR analysis of fractionated
gut contents demonstrated that these bacteria reside in
different spatial niches; the spirochete is free-swimming, whereas
the deltaproteobacterium associates with particulates. Fourth, the
deltaproteobacteria expressing FDH were localized to protozoa via
hybridization chain reaction-FISH, an approach for multiplexed,
spatial mapping of mRNA and rRNA targets. These results underscore
the importance of making direct vs. inference-based gene–
species associations, and have implications in higher termites, the
most successful termite lineage, in which protozoa have been lost
from the gut community. Contrary to expectations, in higher termites,
FDH genes related to those from the protozoan symbiont
dominate, whereas most others were absent, suggesting that a
successful gene variant can persist and flourish after a gut perturbation
alters a major environmental niche
A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone
Recommended standardized procedures for determining exhaled lower respiratory
nitric oxide and nasal nitric oxide have been developed by task forces of the
European Respiratory Society and the American Thoracic Society. These
recommendations have paved the way for the measurement of nitric oxide to
become a diagnostic tool for specific clinical applications. It would be
desirable to develop similar guidelines for the sampling of other trace gases
in exhaled breath, especially volatile organic compounds (VOCs) which reflect
ongoing metabolism. The concentrations of water-soluble, blood-borne substances
in exhaled breath are influenced by: (i) breathing patterns affecting gas
exchange in the conducting airways; (ii) the concentrations in the
tracheo-bronchial lining fluid; (iii) the alveolar and systemic concentrations
of the compound. The classical Farhi equation takes only the alveolar
concentrations into account. Real-time measurements of acetone in end-tidal
breath under an ergometer challenge show characteristics which cannot be
explained within the Farhi setting. Here we develop a compartment model that
reliably captures these profiles and is capable of relating breath to the
systemic concentrations of acetone. By comparison with experimental data it is
inferred that the major part of variability in breath acetone concentrations
(e.g., in response to moderate exercise or altered breathing patterns) can be
attributed to airway gas exchange, with minimal changes of the underlying blood
and tissue concentrations. Moreover, it is deduced that measured end-tidal
breath concentrations of acetone determined during resting conditions and free
breathing will be rather poor indicators for endogenous levels. Particularly,
the current formulation includes the classical Farhi and the Scheid series
inhomogeneity model as special limiting cases.Comment: 38 page
Modeling the Afferent Dynamics of the Baroreflex Control System
In this study we develop a modeling framework for predicting baroreceptor firing rate as a function of blood pressure. We test models within this framework both quantitatively and qualitatively using data from rats. The models describe three components: arterial wall deformation, stimulation of mechanoreceptors located in the BR nerve-endings, and modulation of the action potential frequency. The three sub-systems are modeled individually following well-established biological principles. The first submodel, predicting arterial wall deformation, uses blood pressure as an input and outputs circumferential strain. The mechanoreceptor stimulation model, uses circumferential strain as an input, predicting receptor deformation as an output. Finally, the neural model takes receptor deformation as an input predicting the BR firing rate as an output. Our results show that nonlinear dependence of firing rate on pressure can be accounted for by taking into account the nonlinear elastic properties of the artery wall. This was observed when testing the models using multiple experiments with a single set of parameters. We find that to model the response to a square pressure stimulus, giving rise to post-excitatory depression, it is necessary to include an integrate-and-fire model, which allows the firing rate to cease when the stimulus falls below a given threshold. We show that our modeling framework in combination with sensitivity analysis and parameter estimation can be used to test and compare models. Finally, we demonstrate that our preferred model can exhibit all known dynamics and that it is advantageous to combine qualitative and quantitative analysis methods
Anterior colporrhaphy does not induce bladder outlet obstruction
We aimed to evaluate if anterior colporrhaphy causes incomplete voiding due to bladder outlet obstruction. Women scheduled for anterior colporrhaphy were asked to undergo multichannel urodynamic investigation before surgery and the first postoperative day. Bladder outlet obstruction was assessed using the Blaivas-Groutz voiding nomogram. Maximum flow rate, detrusor pressure and residual volume were compared between pre- and postoperative measurements and between women with and without an abnormal post-void residual volume (PVR; volume exceeding 150 ml). Seventeen women participated. One woman who was unobstructed before surgery was obstructed after surgery. Overall, detrusor pressure and maximum flow rate before and after surgery did not differ. After surgery, six women had an abnormal PVR, one was unable to void, four were mildly obstructed and one moderately obstructed. Urodynamic investigation the first day after anterior colporrhaphy did not show that anterior colporrhaphy induces bladder outlet obstruction. The explanation for postoperative urinary retention can therefore also lie in non-anatomical causes such as postoperative pain and psychological factor
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