MPDA: Microarray pooled DNA analyzer

Background  

Microarray-based pooled DNA experiments that combine the merits of DNA pooling and gene chip technology constitute a pivotal advance in biotechnology. This new technique uses pooled DNA, thereby reducing costs associated with the typing of DNA from numerous individuals. Moreover, use of an oligonucleotide gene chip reduces costs related to processing various DNA segments (e.g., primers, reagents). Thus, the technique provides an overall cost-effective solution for large-scale genomic/genetic research. However, few publicly shared tools are available to systematically analyze the rapidly accumulating volume of whole-genome pooled DNA data.     

Preslaughter holding environment in pork plants is highly contaminated with Salmonella enterica

The objective of this study was to determine whether abattoir pens can provide a Salmonella enterica infection source during the 2 to 4 h of preharvest holding. Previous work has suggested that pigs may be getting infected, but little has been reported on the environmental contamination of abattoir holding pens. For 24 groups of pigs studied ( approximately 150 animals/group) at two high-capacity abattoirs, six pooled fecal samples (n, 10 per pool) were collected from each transport trailer immediately after pigs were unloaded. Holding pens were sampled (one drinking water sample and six pooled floor samples consisting of swabs, residual liquid, and feces) prior to entry of study pigs for the routine holding period ( approximately 2.5 h). After slaughter, cecal contents and ileocecal lymph nodes were collected, on the processing line, from 30 pigs in each studied group. All samples were cultured for the isolation and identification of S. enterica by primary enrichment in GN-Hajna and tetrathionate broths, secondary enrichment in Rappaport-Vassiliadis broth, and plating on brilliant green sulfa and xylose-lysine-tergitol-4 agars, followed by biochemical and serological identification. The study pens were highly contaminated with S. enterica; all holding pens sampled had at least one positive sample. Additionally, 33% (8 of 24) of drinking water samples were positive for S. enterica. All 24 groups of pigs had S. enterica-positive cecal contents and ileocecal lymph nodes, including those groups from transport trailers with no positive samples. From pigs, trailers, and pens, 586 isolates representing 36 different Salmonella serovars were isolated. Of the 353 isolates from pigs (109 from ileocecal lymph nodes plus 244 from cecal contents), 19% were identified as belonging to the same serovars as those isolated from the respective pens; 27% were identified as belonging to the same serovars as those isolated from the trailers. Sixteen percent of the unique serovars were isolated from both pigs and pens, suggesting that pens served as the infection source. This study demonstrates highly contaminated abattoir holding pens and watering sources. It also demonstrates that holding pens can serve as an infection source. This study identifies the abattoir holding pens as a significant hazard and a potential control point for Salmonella contamination in the preharvest pork production chain.     

A method for the cryopreservation of thrombocytes

By using dimethylsulfoxide (0.7 mol/l) a technique of cryoconservation of thrombocyte concentrates was elaborated, with own material-technological possibilities being taken into consideration. In comparison to fresh thrombocytes the results of parameters tested in vitro reveal a mean functional ability of 50%. The survival time of cells stored in this way in vivo may be compared with fresh cells. On this basis HLA-typed single-donor pools could be established for clinical application.     

Bactericidal silver ion delivery into hydrophobic coatings with surfactants

A much studied oil-soluble surfactant, bis[2-ethylhexyl]sulfosuccinate, sodium salt, was ion exchanged into the silver ion form and dissolved into microemulsions of immiscible polyurethane step monomers. Coating and curing of these microemulsions produced polyurethane coatings that exhibit bactericidal activity against representative Gram negative bacteria. After 24 h exposure, 0.006–0.012% weight Ag relative to coating weight (0.0013–0.0025 μmol Ag/cm²) results in the three-log reduction in Escherichia coli. A slightly higher level of 0.031% weight Ag relative to coating weight (0.006 μmol Ag/cm²) killed all of the E. coli after 12 h exposure. Similar results were obtained for Pseudomonas aeruginosa. Since the double-tail surfactant anion promotes reverse micelle formation in many different kinds of oils and solvents, it appears an excellent vector for incorporating low and effective amounts of silver ion into many industrial, hospital, and household coating formulations.     

Oxygen distribution in murine tumors: characterization using oxygen-dependent quenching of phosphorescence.

In the present work, a novel method for detecting hypoxia in tumors, phosphorescence quenching, was used to evaluate tissue and tumor oxygenation. This technique is based on the concept that phosphorescence lifetime and intensity are inversely proportional to the oxygen concentration in the tissue sample. We used the phosphor Oxyphor G2 to evaluate the oxygen profiles in three murine tumor models: K1735 malignant melanoma, RENCA renal cell carcinoma, and Lewis lung carcinoma. Oxygen measurements were obtained both as histograms of oxygen distribution within the sample and as an average oxygen pressure within the tissue sampled; the latter allowing real-time oxygen monitoring. Each of the tumor types examined had a characteristic and consistent oxygen profile. K1735 tumors were all well oxygenated, with a peak oxygen pressure of 37.8 +/- 5.1 Torr; RENCA tumors had intermediate oxygen pressures, with a peak oxygen pressure of 24.8 +/- 17.9 Torr; and LLC tumors were all severely hypoxic, with a peak oxygen pressure of 1.8 +/- 1.1 Torr. These results correlated well with measurements of tumor cell oxygenation measured by nitroimidazole (EF5) binding and were consistent with assessments of tumor blood flow by contrast enhanced ultrasound and tumor histology. The results show that phosphorescence quenching is a reliable, reproducible, and noninvasive method capable of providing real-time determination of oxygen concentrations within tumors.     

血管内皮舒张因子在氧自由基所致慢性缺氧大鼠肺内动脉收缩中的作用

以黄嘌岭(X)-黄嘌呤氧化酶(XO)系统产生氧自由基,应用微量生物测定法观察慢性缺氧(5000m,10d)对大鼠氧自由基所致肺内动脉收缩的影响及内皮舒张因子(EDRF)在其中的作用。慢性缺氧大鼠有内皮的肺内动脉环对氧自由基的收缩反应较正常环境中的对照动物明显增强,加入EDRF灭活剂还原型血红蛋白(RHb)后更加显著;而加入超氧化物歧化酶(铜锌SOD)后则减弱,甚至消除。反之,不论加入RHb或SOD对氧自由基所致去内皮肺内动脉环的收缩反应均无明显影响。上述结果表明慢性缺氧引起肺内动脉收缩增强与EDRF有密切关系:慢性缺氧可能使EDRF的作用减弱,肺内动脉对氧自由基的反应性增强。表示EDRF及其与氧自由基的关系在慢性缺氧性肺动脉高压的形成中可能具有十分重要的意义。     

Comparative studies of the adsorption behavior of plasma proteins to heparin-coated surfaces]

Over the past 10 years, investigations have shown that heparin coating optimizes haemocompatibility in extracorporeal circulation systems. To date, however, the mechanisms involved have not been identified. 20 ml of fresh human blood were circulated in an in vitro closed-loop model with and without heparin coating. Using a newly developed ELISA, a quantitative analysis of the adsorbed plasma proteins was done. In addition, changes in coagulation, complement and blood cell releasing factors were measured by ELISA methods: prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin-III complex (TAT), PMN-elastase, beta-thromboglobulin (beta-TG) and terminal complement-complex (TCC). In uncoated tubing, high concentrations of fibrinogen, fibronectin, prothrombin, vitronectin, alpha 2-macroglobulin, von Willebrand factor and complement factor C3 were found. Large amounts of antithrombin-III, HMWK and C1-esterase inhibitor were found on the heparinized surfaces. In addition, the concentrations of the soluble plasma protein markers F1 + 2, FPA, PMN-elastase, TCC and beta-TG were significantly lower (p < 0.05) in the presence of heparin coating. The haemocompatibility of "foreign" surfaces depends largely on the extent to which the processes of activation and inhibition of humoral and cellular mediators permanently occurring at the natural endothelium can be simulated. Owing to the low adsorption of procoagulatory and proinflammatory enzymes, heparin-coated surfaces demonstrate significantly improved haemocompatibility.