Biomedical subjects
Publications and source records attributed to J Bai.
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Using potato dextrose agar medium, 40 strains of microorganisms were isolated from leftover fermented corn flour samples involved in outbreaks of food poisoning. All strains produced powerful toxins which caused the same intoxication to mice, dogs, and monkeys as the leftover food samples. On the basis of results obtained from the morphology of this bacteria and its colony, from biochemical tests, and from the G-C mole percentage in DNA, the bacteria was identified as Flavobacterium farinofermentans nov. sp. (Meng, Z. and Wang, D.).
UNLABELLED: In previous study in our laboratory, we had shown the effect of radiation on morphometry of small bowel of rats after 7 days of a single external doses of 1,000 rads with liver protection. Our aim was to determine the effect of the same procedure of gamma radiation in rats on the morphometry and D-Xylose absorption 7, 14 and 21 days after injury and compared with a control group matched by weight. The D-Xylose absorption was measured by plasmatic D-Xylose, 60' after an intragastric doses of the pentose (0.5 grs/kg of body weight). RESULTS: In the control group the mucosal thickness was 880 +/- 40 mu (X +/- SD), the vellous height was 640 +/- 37.6 mu and the xylosemia 15.91 +/- 11.39 mg%. At 7 days in the irradiated group (n: 11) the weight decreased 33.36 +/- 6.29% (Vs. control p less than .001), the mucosal thickness and the vellous height were 666 +/- 97 (p less than .001) and 466 +/- 66.9 mu (p less than .001) and the xylosemia 6.16 +/- 2.3 (p less than .05). The figures at 14 days (n: 16) showed improving and completed recovery at 21 days (n: 14). Irradiated rats were shown to be affected in weight, morphology and D-Xylose absorption, they began recovering after 7 days, and completed recovery at 21 days.
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Keshan disease, an endemic cardiomyopathy in China, was prevalent in rural areas located in a long belt region where the selenium content was low in foods. Intervention studies with well controlled subjects revealed a prophylactic effect of sodium selenite. Multifocal necrosis and fibrous replacement of the myocardium characterized the histopathological features and myocytolysis was present in most cases. Ultrastructural observations on twelve postmortem cases revealed remarkable changes in many organelles of which mitochondria appeared to be most important in the development of myocardial lesions. Three kinds of specific granules, which have not been found in other reports on cardiomyopathies, were represented and other factors which might also contribute to the aetiology are discussed.
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During a 5-year time span, 118 addicted women gave birth to viable infants. These patients were subject to an increased incidence of complicating medical problems as well as many obstetric problems leading to maternal or fetal risk. The obstetrician should be aware of the possibility of addiction and its effects on pregnancy, and when possible, appropriate management should be initiated. Intensive care of the neonate must be begun as soon as possible.
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Balloon configuration and control scheme are important for the optimization of assistance of the failing heart with an intraaortic balloon pumping device. In this work, the configuration of a multi-chamber balloon and control schemes have been investigated by using a hemodynamic model and computer simulation methods. Following the simulation study, physical testing and animal experiments were performed to demonstrate the simulation results. Results show that the optimal configuration and controlled multi-chamber balloon can provide better assistance to the failing heart. Based on the simulation and experimental results, it was found that the shape of the rear chamber of a multi-chamber balloon is critical. The optimal control scheme was to inflate the rear chamber first and deflate it last.
The bacteriocin nisin was extracted in PEG/salt aqueous two-phase systems (ATPS) using the property that the systems can extract hydrophobic proteins. The concentrations of the phase-forming components, PEG 4000 and Na(2)SO(4), were optimized for nisin recovery by means of statistical experimental designs, and it was found that they strongly influenced nisin recovery. The optimal composition of ATPS was found to be 15.99% (w/w) PEG 4000 and 15.85% (w/w) Na(2)SO(4) (pH 2), and the optimal ATPS allowed an 11.60% increase of nisin recovery compared to the standard method of nisin assay.
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The aim of this study was to investigate the reversal of adriamycin resistance in human ovarian cancer cells by ultrasound exposure from perspectives of apoptosis and mdr1 gene. Apoptosis was determined by flow cytometry and mdr1 level by reverse transcription-polymerase chain reaction (RT-PCR). Apoptosis indexes were improved in groups in which ultrasound exposures were applied. RT-PCR did not support that insonation-decreased mdr1 level. These findings suggested that the ultrasound-enhanced therapeutic efficacy was not mediated via modulating gene expression, and ultrasound maybe lowered thresholds for apoptosis and oncosis in chemoresistant ovarian cancer cells.
Mitochondria dysfunction induced by reactive oxygen species (ROS) is related to many human diseases and aging. In physiological conditions, the mitochondrial respiratory chain is the major source of ROS. ROS could be reduced by intracellular antioxidant enzymes including superoxide dismutase, glutathione peroxidase and catalase as well as some antioxidant molecules like glutathione and vitamin E. However, in pathological conditions, these antioxidants are often unable to deal with the large amount of ROS produced. This inefficiency of antioxidants is even more serious in mitochondria, because mitochondria in most cells lack catalase. Therefore, the excessive production of hydrogen peroxide in mitochondria will damage lipid, proteins and mDNA, which can then cause cells to die of necrosis or apoptosis. In order to study the important role of mitochondrial catalase in protecting cells from oxidative injury, a HepG2 cell line overexpressing catalase in mitochondria was developed by stable transfection of a plasmid containing catalase cDNA linked with a mitochondria leader sequence which would encode a signal peptide to lead catalase into the mitochondria. Mitochondria catalase was shown to protect cells from oxidative injury induced by hydrogen peroxide and antimycin A. However, it increased the sensitivity of cells to tumor necrosis factor-alpha-induced apoptosis by changing the redox-oxidative status in the mitochondria. Therefore, the antioxidative effectiveness of catalase when expressed in the mitochondrial compartment is dependent upon the oxidant and the locus of ROS production.