Search PubMed⌕ Search

Biomedical subjects

C Huang

Publications and source records attributed to C Huang.

At least 559 records · Page 31Linked to original sources
PubMedDate not supplied

Oxidative damage in cerebral vessels of diabetic db/db mice.

BACKGROUND: Oxidative stress in diabetes mellitus has recently received increasing attention as it has been proven to be associated with the development of diabetic vascular complications. Our aim was to examine whether microvascular changes, including oxidative damage, were induced in the brains of diabetic animals. METHODS: The expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, the binding of cationized ferritin, a marker for evaluating endothelial glycocalyx, to the endothelial cells of capillaries and vascular permeability of intravenously injected horseradish peroxidase were examined in the cortices of 12- and 20-week-old db/db and db/+m mice. RESULTS: Immunostaining for 8-OHdG was clearly seen in the vessels of the cortex of 20-week-old db/db mice, but was hardly seen in those of mice in the other groups. The immunopositive area of 8-OHdG was significantly increased in the cortex of 20-week-old db/db mice compared with that of 20-week-old db/+m mice. No extravasated leakage of horseradish peroxidase was seen in any groups of mice, while the numbers of cationized ferritin particles binding to the endothelial cells was significantly decreased in 12- and 20-week-old db/db mice compared with that of db/+m mice at the same age, respectively. CONCLUSION: These findings suggest that changes in endothelial glycocalyx are induced in db/db mice and, in addition, the long-term diabetic condition of these mice induces oxidative DNA damage to the cerebral vessels.

8-Hydroxy-2'-Deoxyguanosine↗
PubMedDate not supplied

Spontaneous spinal cerebrospinal fluid leak and intracranial hypotension.

A case of intracranial hypotension with spontaneous cerebrospinal fluid (CSF) leak was reported. A Tc-99m diethyltriaminepentacetic acid radionuclide cisternography (RNC) showed the accumulation of radioactivity in the area of the subarachnoid space, the poor migration of the isotope over the convexities, and the early appearance of kidney and bladder activity. To localize the site of CSF leak, RNC will be the choice, and when the time comes, RNC will work well in the location of the leak.

Adult↗
PubMedDate not supplied

Performances of the immunomagnetic separation method for Cryptosporidium in water under various operation conditions.

Immunomagnetic separation (IMS) has been specified as a standard method for the measurement of Cryptosporidium in some countries. In this study, the IMS method was evaluated on the basis of the recovery efficiencies of Cryptosporidium oocysts at various IMS operation conditions. The average recovery for different Cryptosporidium concentrations in deionized water was 82.6 +/- 18.2% (n = 52). No significant change in recovery was observed by altering the debris ratio of the water samples. The efficiency was increased by prolonging the reaction time, and by increasing the amount of immunomagnetic beads. The recoveries of oocysts seeded in an Eppendorf with a small reaction volume were similar to those seeded in glass tubes with 10 times the reaction volume. The recovery efficiency of oocysts was reduced significantly when the reaction buffer was replaced by PBS. In conclusion, this method has good reproducibility and high recovery.

Animals↗
PubMedDate not supplied

Biodegradation of hydrogen sulfide by a laboratory-scale immobilized Pseudomonas putida CH11 biofilter.

A heterotrophic Pseudomonas putida CH11 was isolated from livestock farming wastewater and applied for the treatment of H2S-containing gas. Extensive tests including removal characteristics, metabolic products, and removal efficiencies of H2S by P. putida CH11 were examined in batch and continuous systems. The optimum pH required to remove hydrogen sulfide was found in the range of 6-8. The maximum removal rate and the saturation constant were calculated to be Vm = 1.36 g S/day.kg dry bead and Ks = 45.9 ppm, respectively. The main metabolic product of H2S oxidation was determined to be elemental sulfur. When P. putida CH11 was immobilized within Ca alginate, the cells exhibited high H2S removal efficiency, in excess of 96%, at concentration of hydrogen sulfide from 10 to 150 ppm (flow rates of 36 and 72 L/h). These results suggest that P. putida CH11 immobilized within Ca alginate has the potential to be used as a H2S removal agent.

Air Pollutants↗
PubMedDate not supplied

Biotreatment of ammonia from air by an immobilized Arthrobacter oxydans CH8 biofilter.

A heterotrophic Arthrobacter oxydans CH8 that was capable of removing NH3 from NH3 containing gas was isolated from livestock farming wastewater. The A. oxydans CH8 was immobilized with calcium alginate packed into filter column. Metered NH3-containing gas was partially humidified and passed through the glass column. Extensive tests including the removal characteristics, the removal efficiencies, and the metabolic products of NH3 by A. oxydans CH8 were conducted. Additionally, the operation criteria for the biofilter was also established. NH3 removel capacities were elevated by the immobilized-cell (biological conversion) method and the BDST (bed depth service time) method (physical adsorption), respectively. The optium temperature for removing NH3 was 30 degrees C, while the nitrification ability remained 80% at 40 degrees C. The high efficiency (> 97%) in the removal of NH3 was attained at 36 L/h with pH control and was not decreased because of high NH3 inlet concentration. In addition, the high maximum removal rate (1.22 g of N/day (kg of bead)) enhanced the use of the biofilter in industrial-scale NH3(g) pollution control. The ability to remove NH3 at high inlet concentration and temperature suggested that the immobilized A. oxydans CH8 biofilter has potential in processing NH3 gas.

Adsorption↗
PubMedDate not supplied

Fibronectin receptor structures in the VLA family of heterodimers.

Multiple cell surface proteins of relative molecular mass 115,000-155,000 (Mr 115K-155K) have been implicated as receptors mediating adhesion to extracellular matrix proteins. But the organization and relatedness of these peptides has remained unclear. In separate studies, the 'very late antigens' VLA-1 (Mr 210K/130K) and VLA-2 (Mr 160K/130K) were initially characterized as surface heterodimers appearing 2-4 weeks after in vitro stimulation of human T cells. Three more VLA heterodimers have since been discovered, which, like VLA-1 and VLA-2, are each composed of unique alpha-subunits in association with a common 130K beta subunit. This paper shows that the common VLA beta-subunit is equivalent to subunits found in structures with known fibronectin and laminin receptor activity, and that VLA-3 and VLA-5 are similar or identical to these previously defined receptors for adhesion molecules. Antibody blocking studies confirmed that at least some of the widely distributed VLA proteins of previously unknown function are involved in cell adhesion to fibronectin and laminin. We suggest that the VLA family of receptors may provide cells with multiple independent substrate adhesion capabilities.

Amino Acid Sequence↗
PubMedDate not supplied

Conversion to cardiopulmonary bypass in off-pump coronary artery bypass grafting: its effect on outcome.

The surgical outcome of patients requiring conversion to cardiopulmonary bypass (CPB) during myocardial revascularization using the less invasive surgical approach (LISA) was assessed. The LISA was recently introduced as a technique for complete myocardial revascularization without CPB. It combines avoidance of CPB with the versatility of a median sternotomy for access to all coronary vessels. We have previously demonstrated reduced risk-adjusted mortality and complications in off-CPB coronary artery bypass grafting (CABG) using LISA compared to standard myocardial revascularization. From January to December 1997, 1210 patients underwent isolated CABG at our institution. Of these patients, 832 (63%) were scheduled as on-CPB cases and 378 (37%) as off-CPB. Of the off-CPB patients, 48 were converted to CPB. Team A surgeons used LISA as their primary strategy for CABG whereas team B surgeons used off-CPB CABG in selected patients. Conversions were divided in three classes: Class I patients were converted when the surgeon considered complete revascularization impossible off-CPB; Class II patients were converted due to hemodynamic instability during the procedure; and Class III patients were converted due to graft malfunction, determined by flow measurements or clinical evidence. There were four deaths. All had perioperative infarctions and required intra-aortic balloon pump (IABP). Conversion to CPB occurred in up to 25% of patients scheduled for off-CPB CABG. When off-CPB cases are done using the comprehensive LISA technique and modern technology, conversion rates may be reduced to 11%. Conversion is in general well tolerated except when it is instituted for graft malfunction combined with hemodynamic instability or collapse.

Adult↗
PubMedDate not supplied

Hantavirus pulmonary syndrome associated with Monongahela virus, Pennsylvania.

The first two recognized cases of rapidly fatal hantavirus pulmonary syndrome in Pennsylvania occurred within an 8-month period in 1997. Illness in the two patients was confirmed by immunohistochemical techniques on autopsy material. Reverse transcription-polymerase chain reaction analysis of tissue from one patient and environmentally associated Peromyscus leucopus (white-footed mouse) identified the Monongahela virus variant. Physicians should be vigilant for such Monongahela virus-associated cases in the eastern United States and Canada, particularly in the Appalachian region.

Adult↗
PubMedDate not supplied

PI-3 kinase in signal transduction, cell transformation, and as a target for chemoprevention of cancer.

Phosphatidylinositol-3 kinase (PI-3 K) plays a central role in a broad range of biological effects. However, little is known about its role in phorbol ester- or epidermal growth factor (EGF)-induced signal transduction to the transcriptional machinery of the nucleus and in tumor promoter-induced cell transformation. We have used JB6 cells to study the role of PI-3 K in 12-O-tetradecanoylphorbol-13-acetate (TPA)- or EGF-induced AP-1 activation and neoplastic cell transformation. We demonstrated that TPA, EGF and insulin induce PI-3 K activity in JB6 cells. The induced PI-3 K activity was blocked by a dominant negative mutant of PI-3 K, and by wortmannin or LY294002. Blocking of PI-3 K activity by these inhibitors also blocked TPA- or EGF-induced AP-1 activity and cell transformation. Furthermore, we have investigated the role of PKC and its isozymes in the synergistic induction of PI-3 K by TPA and insulin and found that bisindolylmaleimide, a PKC inhibitor, inhibits TPA-induced PI-3 K. Overexpression of a dominant negative PKC epsilon, but not dominant negative PKC alpha, blocks the TPA- or TPA plus insulin-induced PI-3 K activity. Inositol hexaphosphate (InsP6) is one of the most promising chemopreventive agents as demonstrated by Shamsuddin et al. and others. InsP6 profoundly inhibits EGF- or TPA-induced cell transformation and the signal transduction cascade to Erks and AP-1 activation. InsP6 also inhibits TPA- or EGF-induced PI-3 K activity in vivo and in vitro. These results suggest that the anticarcinogenesis action of InsP6 may be through inhibition of PI-3 K and inhibition of the AP-1 pathway. Because InsP6 is a naturally occurring compound with virtually no toxicity, and may be an effective anticarcinogenesis agent in humans, PI-3 K and AP-1 activities may be useful biomarkers for the effectiveness of InsP6 in clinical studies.

Animals↗
PubMedDate not supplied

Transactivation of AP-1 in AP-1-luciferase reporter transgenic mice by arsenite and arsenate.

Arsenic is a recognized carcinogen, which acts as a tumor promoter rather than as an initiator. Signal transduction pathways leading to activation of AP-1 and mitogen-activated protein kinases are proposed to be responsible for the tumor promotion activity by arsenic. Induction of AP-1 DNA binding activity and c-jun and c-fos expression was reported to be only observed in cells responding to arsenite, but not to arsenate. However, in this study, we found that both arsenite and arsenate could induce transactivation of AP-1 in mouse epidermal JB6 AP-1-luciferase reporter stable transfectants, P+1-1. This induction of AP-1 activity by arsenic appears to be through activation of mitogen-activated protein kinases and protein kinase C because increased AP-1 activity by arsenite could be blocked by either treatment of cells with PD98059 or overexpression of dominant negative protein kinase Ca. Furthermore, both arsenite and arsenate could induce transactivation of AP-1 in AP-1-luciferase reporter transgenic mice.

Animals↗