Salmonella serovars and antimicrobial resistance profiles in beef cattle, slaughterhouse personnel and slaughterhouse environment in ethiopia.

The present study was undertaken to determine the occurrence, distribution and antimicrobial resistance profiles of Salmonella serovars in slaughter beef cattle, slaughterhouse environment and personnel engaged in flaying and evisceration during slaughtering process. A total of 800 samples (each sample type, n = 100) consisting of swabs from hides, slaughterhouse personnel hands at flaying and evisceration, rumen and caecal contents, mesenteric lymph nodes, carcasses and holding pens were collected. Of the total 100 beef cattle examined, 14% were Salmonella positive in caecal content and/or mesenteric lymph nodes. Of the various samples analysed, Salmonella was detected in 31% of hides, 19% of rumen contents, 8% of mesenteric lymph nodes, 6% of caecal contents, 2% of carcass swabs, 9% of palm swabs taken from the hands of personnel in the slaughterhouse during flaying (7%) and evisceration (2%), and in 12% of holding pen swabs. The Salmonella isolates (n = 87) belonged to eight different serovars of which S. Anatum (n = 54) and S. Newport (19) were the major serovars and both serovars were detected in all sample sources except in carcass swabs. Eighteen of the 87 (20.7%) Salmonella serovars consisting of Newport (n = 14), Anatum (n = 3) and Eastbourne (n = 1) were resistant to one or more antimicrobials. Among the antimicrobial resistant Salmonella serovars, S. Newport was multidrug resistant (15.6%) and exhibited resistance to streptomycin, sulphisoxazole and tetracycline.

Textile-templated electrospun anisotropic scaffolds for tissue engineering and regenerative medicine.

Cardiovascular diseases, specifically myocardial infarction and end-stage heart failure represent some of the major pathologies that threaten human life. Here we present a novel approach for a bioactive cardiac patch based on a combination of biomedical and textile manufacturing techniques in concert with nano-biotechnology based tissue-engineering stratagems. The technological goal is to create BioNanoTextiles™ (BNT) by using "conventional" fabrics as templates for creating three-dimensional nanofibrous scaffolds. Electrospinning nanofibrous scaffolds templated after "ordinary" textiles is a novel way to create complex-patterned, 3-D scaffolds intrinsically mimicking some of the anisotropic structural features of the ventricular wall's extracellular matrix. In preliminary studies, we established that this approach will yield anisotropic 3-D scaffolds with mechanical properties dependent upon the yarn type of the textile-templates. These scaffolds are biocompatible, as inferred from their support of H9C2 cardiac myoblast adhesion which promotes their proliferation as well as cardiac-like anisotropic organization. The use of textile manufacturing strategies will enhance the complexity of the 3-D scaffold structures and enable their commercialization, while providing an opportunity for the textile industry to advance established "low-tech" manufacturing technologies into the realm of "high-tech" BioNanoTextiles.

Dentin micro-architecture using harmonic generation microscopy.

OBJECTIVES: We present a novel way to create high-resolution three-dimensional images of tooth dentin by harmonic generation scanning laser microscopy. METHODS: The images were taken using a pulsed infrared laser. Three-dimensional reconstruction enables the visualization of individual tubules and the collagen fibrils mesh around them with an optical resolution of approximately 1 microm. RESULTS: The images show micro-morphological details of the dentinal tubules as well as the collagen fibrils at a depth of up to about 200 microm. The data show that while collagen fibrils are organized in planes perpendicular to the tubules, close to the dentin enamel junction they lie also along the long axis of the tubules. CONCLUSIONS: The unique 3D information opens the opportunity to study the collagen fibril arrangement in relation to the tubule orientation within the dentin matrix, and may be applied to study the micro-morphology of normal versus altered dentin.

Immunohistochemical localization of adenosine deaminase in human benign extrathymic lymphoid tissues and B-cell lymphomas.

Immunomorphologic methods were utilized to localize adenosine deaminase (ADA) in extrathymic benign lymphoid tissues and B-cell lymphomas. In reactive lymph nodes, tonsils and appendix, germinal centers displayed strong ADA-positive nuclear staining in small cleaved lymphocytes and weak nuclear and/or cytoplasmic staining in large lymphoid cells. A significant proportion of ADA-positive lymphocytes in the germinal centers were B-cells. The mantle zone of secondary follicles did not stain for ADA. The plasma cells in the medullary cords demonstrated mainly cytoplasmic staining. In the spleen, ADA-positive lymphocytes were located in the periarteriolar sheath and paratrabecular white pulp. In lymphoma B-cells, patterns of ADA staining were similar to those observed in normal B-lymphocytes of similar morphology. This study demonstrated that human normal and lymphoma B-lymphoid cells are heterogeneous with respect to ADA expression. This heterogeneity appears to be associated with differentiation and/or proliferation of B-lymphocytes.

Morphologic changes and immunohistochemical localization of adenosine deaminase in tissues of rats given injections of 2'-deoxycoformycin.

2'-Deoxycoformycin (DCF) is a potent inhibitor of adenosine deaminase (ADA) and a potential antineoplastic and immunosuppressive agent. In this study the kinetics of ADA expression was assessed by immunomorphologic and enzymatic methods in tissues of ACI rats given injections of DCF. The rats received a daily ip injection of 10 mg DCF/kg for 3 consecutive days. This treatment destroyed cortical thymocytes, whereas lymphocytes of the thymic medulla were mainly preserved. In control phosphate-buffered saline-injected rats, cortical thymocytes were not affected morphologically and displayed strong ADA staining. It was found unexpectedly that injections of DCF produced activation and, possibly, differentiation of B-cells in the mesenteric lymph nodes and spleen. These activated B-lymphocytes and plasma cells stained strongly for ADA. Transient changes in patterns of ADA expression were also observed in endothelial cells of blood vessels and liver Kupffer's cells, but these changes were not accompanied by degeneration of the cells. The treatment with DCF did not result in any permanent abnormalities in the rat tissues.

Stimulation of peripheral blood lymphocytes of children by influenza vaccine.

Cell cultures were performed with the blood of children, adults and umbilical cords in an examination of the effects of influenza vaccines. Commercially prepared whole virus vaccines containing swine +/- human virus antigens had a stimulatory effect upon peripheral blood lymphocytes of children but not adults. The stimulatory effect was shown to be retained by a fraction of whole influenza virus vaccine, but not subunit virus vaccine, is known to stimulation of blood lymphocytes by commercial subunit vaccines of either monovalent swine influenza or a trivalent composition. Immunization with whole influenza virus vaccine, but not subunit virus vaccine, is known to produce a high incidence of generalized reactions in children but not adults. The lymphocyte stimulation observed here may represent an in vitro counterpart of the in vivo reactions.