Prevalence of Gastrointestinal Pathogens in Sub-Saharan Africa: Systematic Review and Meta-Analysis

A significant proportion of vulnerable people in sub-Saharan Africa (SSA) remain at risk for contracting diarrhoeal diseases due to the presence of many risk factors facilitating their transmission. A systematic review of published articles from the SSA region was done to determine the prevalence and types of diarrhoeal pathogens in circulation; based on a search of databases; including EBSCO host; PubMed; Scopus; Science Direct; Google scholar and Web of Science was done between September 2009 and December 2010. Data were summarized from 27 studies; with pooled data analysed and reported. Pathogens were isolated from between 26.8-65.6of cases; with an overall isolation rate of 55.7(95CI; 48.2-62.9). Isolation rates were highest amongst adult cases followed by children; and the odds of isolating a pathogen was greater in diarrhoeal cases (Odds Ratio 4.93 (95CI; 1.99 to 12.23); than in asymptomatic controls. Overall isolation ranged from 8to 99; and heterogeneity testing suggests differences between age groups (Q=5.806; df=2; P=0. 055). Mixed E. coli spp.; (29.95); Cryptosporidium (21.52); Cyclospora (18); Entamoeba; (13.8); Shigella spp. (10.49); Salmonella spp. (8.36); and Campylobacter spp. (8.33); were most commonly reported; and rotavirus was the most common virus isolated. This is the first review to look at the range of enteric pathogens circulating in SSA; and has confirmed high rates of isolation of pathogens from diarrhoeal cases. Public health practitioners can use this information to understanding the challenges related to diarrhoeal illness and set priorities for their prevention and control

Fas ligand-induced apoptosis as a mechanism of immune privilege.

The eye is a privileged site that cannot tolerate destructive inflammatory responses. Inflammatory cells entering the anterior chamber of the eye in response to viral infection underwent apoptosis that was dependent on Fas (CD95)-Fas ligand (FasL) and produced no tissue damage. In contrast, viral infection in gld mice, which lack functional FasL, resulted in an inflammation and invasion of ocular tissue without apoptosis. Fas-positive but not Fas-negative tumor cells were killed by apoptosis when placed within isolated anterior segments of the eyes of normal but not FasL-negative mice. FasL messenger RNA and protein were detectable in the eye. Thus, Fas-FasL interactions appear to be an important mechanism for the maintenance of immune privilege.

Consumer Attitudes Toward Irradiated Food: Results of a New Study.

A survey was conducted to determine current consumer attitudes toward irradiation. The mailed questionnaire was designed to be self-administered. Results were obtained from responses of 54% of 918 questionnaires mailed out to consumers in the metro-Atlanta area. Results indicated that 72% of consumers are aware of irradiation and, among these, 87.5% indicated that they have heard about irradiation but do not really know that much about it. Over 30% of consumers believe that irradiated food is radioactive. Consumers are less concerned about irradiation than they are about food additives, pesticide residues, animal drug residues, growth hormones, and bacteria. The risk to workers and environmental issues are among the top concerns regarding irradiation. The percentage of consumers who would buy irradiated food is 45%; 19% would not buy it, and others are undecided. Results indicate that a more favorable response will be observed when a choice of irradiated poultry, meats, and seafood is offered.

Synthesis and cytotoxic evaluation of some 6-arylidene-2-(alpha-hydroxyamino-alpha-arylmethyl)cyclohexanone oximes and related compounds.

Reaction of 2,6-bis-(phenylmethylene)cyclohexanone (1) with a 4-molar excess of hydroxylamine hydrochloride and sodium acetate to produce the corresponding oxime 2 gave rise to 2-(alpha-hydroxyamino-alpha-phenylmethyl)-6-phenylmethylenecyclohexan one oxime (5a), whose structure was deduced from high-resolution proton nuclear magnetic resonance spectroscopy and confirmed by X-ray analysis. Compound 2 was eventually prepared from 1 with hydroxylamine per se and not with a mixture of hydroxylamine hydrochloride and sodium acetate. Ten analogues of 5a, namely 5b-5k, were prepared and evaluated for cytotoxicity. Six of the 11 compounds in series 5, as well as 1, showed activity in the 240-950 microM range against murine mammary EMT6 cells. Series 5 was also examined for cytotoxicity in an in vitro screen conducted by the National Cancer Institute with approximately 54 cell lines, and four compounds demonstrated selective toxicity toward various groups of tumors.

Freeze-thaw effects on the detection of blood group substances in detergent extracts by enzyme-linked immunosorbent assays (ELISA).

The sensitivity of an enzyme-linked immunosorbent assay (ELISA) for human blood group antigens extracted from blood stains with the surfactant, n-octyl-beta-D-glucopyranoside (OBG), at concentrations below the critical micelle concentration can be increased by the introduction of a single freeze-thaw step. The ELISA signals increase from 3- to 4-fold for OBG extracts of 80 nl bloodstains. The ELISA signal enhancement occurs irrespective of the age of the bloodstains, at least for bloodstains up to 1 year old. The origin of the effect has been investigated and its is demonstrated that the freeze-thawing cycle increases the extent of adsorption of the blood group determinants in OBG-solubilized complexes onto microtitre plates. Gel filtration has been used to analyse the composition of OBG extracts of bloodstains in terms of the carriers of the blood group substances, protein and phospholipid in fresh and freeze-thawed extracts. It was found that freeze-thawing alters the distribution of blood group active material in the lipid-protein OBG complexes leading to a greater proportion of blood group active material in higher molecular weight complexes. The freeze-thaw effect is eliminated on the addition of a cryoprotectant, such as glycerol, and the factors which contribute to changes in the microstructure of OBG extracts on freeze-thawing are discussed.

Assay restriction profiles of three monoclonal antibodies recognizing the G3m(u) allotype. Development of an allotype specific assay.

Three monoclonal antibodies raised against a purified human IgG3 paraprotein were found to exhibit a restriction profile for IgG3/G3m(u) and pan-IgG specificity which was dependent on the assay system. When adapted to an IgG3 subclass capture ELISA, all three McAbs discriminated between paraproteins expressing G3m(u) and antithetical markers G3m(st). One of the antibodies (PNF69C) was selected and conditions were optimised for Gm typing purposes. Using this system G3m(u) could be detected on captured IgG3 derived from human sera. This system may prove useful in the elucidation of Gm allotype profiles.

A simple theoretical treatment of a competitive enzyme-linked immunosorbent assay (ELISA) and its application to the detection of human blood group antigens.

A theory has been developed to explain the behaviour of a competitive enzyme-linked immunosorbent assay (ELISA) in which an immobilized antigen competes with a liquid-phase antigen for a limiting amount of antibody. The binding of antibody to antigen on a solid surface (microtitre well) is described in terms of Langmuirian adsorption with a binding constant kappa. Two equations are presented to describe the behaviour of the ELISA signal as a function of competing antigen concentration; an exact equation and an approximate equation which can be used when the surface coverage of the immobilized antigen is not known. It is shown how curves of ELISA signal vs. competing antigen concentration depend on K/kappa [antibody]. The theory has been tested using several immobilized blood group A antigens competing with ovarian cyst fluid A substance and found to adequately describe these competitive ELISAs which have a detection limit of approximately 1 ng of blood group antigen.

Evaluation of monoclonal antibodies with putative specificity for human IgG allotypes.

Fourteen monoclonal antibodies (MAbs) of putative specificity for human IgG allotypes and isoallotypes were evaluated for reactivity and specificity in 8 different assay systems. The study showed that the MAbs tested could be classified into 1 of 4 groups: those exhibiting allotypic specificity regardless of the assay system, allotypic specificity dependent on the assay system, isoallotypic specificity, and those showing neither allotypic nor isoallotypic specificity. These observations were presumably dependent on antigen presentation, epitope integrity and/or antibody multispecificity. For the G1m(a), G1m(f), G1m(z), G3m(g) and G3m(u) specificities, MAbs have been produced which can be used for routine typing purposes in defined haemagglutination and enzyme-linked immunosorbent assay systems. MAbs are also available that show 'non-g' isoallotypic specificity.

Specific capture of ABH blood group antigens of the red cell or body fluids by double antibody sandwich-ELISA.

A double antibody sandwich-ELISA method for the detection of the ABH blood group of each constituent of mixed stains is described. Extracts from mixed stains were applied to microtitration plates coated with rabbit polyclonal antisera to red cells or body fluids. ABH antigens in body fluid stains which were captured by the polyclonal antibodies were detected by monoclonal anti-A and -B and enzyme-conjugated anti-mouse immunoglobulin. By this procedure, ABH antigens of only saliva, semen or red cells could be detected from mixed stains, but no ABH antigen capture activity was observed using anti-sweat, -milk, -vaginal secretion, -erythrocyte membrane and -band 3 antibodies.

Histiocytic malignant lymphoma arising in the midfacial soft tissues.

Histiocytic malignant lymphoma arising in the midfacial soft tissues represents an uncommon clinical disorder. We report our experiences with a 63-year-old man with nasal obstruction secondary to a nasal septal mass that developed four weeks after a routine septoplasty. Final pathologic appearance after multiple biopsies was consistent with histiocytic malignant lymphoma. Clinical features, histopathologic findings, therapy, and prognosis are discussed.

The effects of detergent on the enzyme-linked immunosorbent assay (ELISA) of blood group substances.

The detergents 1-0-n-octyl-beta-D-glucopyranoside (OBG) and sodium n-dodecyl sulphate (SDS) have been used to extract blood group substances from human erythrocyte membranes for detection by enzyme-linked immunosorbent assay (ELISA). The effect of detergent concentration on the extraction process and detection by ELISA have been investigated. Detergent extraction increased the ELISA response relative to response from membrane suspensions approximately 1000-fold. Optimum responses occurred using detergent concentrations near the critical micelle concentration (cmc) for OBG and below the cmc for SDS. High detergent concentrations interfered with the ELISA but this effect was reduced by dilution of the extracts before adsorption of antigen on the microtitre wells. The interference effects of detergent on ELISA were also investigated using ovarian cyst glycoproteins as antigen. It was found that detergents inhibit the assay at the initial stage by competing with antigens for adsorption sites on the microtitre well surface and that subsequent detergent can displace pre-bound antigen. The results are discussed in terms of detergent binding to proteins (and glycoproteins) in relation to free (unbound) detergent concentration.

Bloodstain allotyping: an ELISA method for G1m(3).

A sandwich ELISA method has been developed for typing bloodstains for the G1m(3) allotype, using a commercial monoclonal reagent. The method is more sensitive than haemagglutination-inhibition methods, giving good results with plasma and with bloodstain extracts diluted 1 in 10 000, and provides an objective assessment of results. In its present form, however, it is not suitable for saliva and semen typing.

Species identification of blood and saliva stains by enzyme-linked immunoassay (ELISA) using monoclonal antibody.

An indirect enzyme-linked immunoassay (ELISA) method for the identification of human blood and saliva stains is reported. The method uses a monoclonal antibody which reacts with human immunoglobulin G (IgG) in extracts of blood and saliva stains up to 16 months old. Semen stain extracts gave weak or negative results. For routine screening purposes dilutions of 1:1000 for bloodstain extracts and 1:100 for saliva stain extracts would be suitable. Of 32 other animal species tested, only chimpanzee, mouse, rat, and eel cross-reacted significantly, and the presence of the last three was clearly indicated by appropriate controls. The monoclonal antibody gave poor results in the crossover and gel diffusion techniques.

The sexing of bloodstains by testosterone: total protein ratio determination.

A simple method for the extraction of testosterone from bloodstains followed by its measurement by radioimmunoassay is described. Complete discrimination of males and females was achieved with measured bloodstains as small as 40 microliters. With stains of unknown volume the total protein content of the stain was determined as an internal reference level. Using the testosterone/protein ratio unequivocal identification was possible for 75% of the stains from males and 50% from females.