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Biomedical subjects

G Wu

Publications and source records attributed to G Wu.

At least 559 records · Page 31Linked to original sources
PubMed1993

Effect of brain edema on infarct volume in a focal cerebral ischemia model in rats.

BACKGROUND AND PURPOSE: Infarct volume is one of the common indexes for assessing the extent of ischemic brain injury following focal cerebral ischemia. Accuracy in the measurement of infarct volume is compounded by postischemic brain edema that may increase brain volume in the infarcted region. We evaluated the effect of brain edema on infarct volume determined by triphenyltetrazolium chloride and hematoxylin and eosin stains in a focal cerebral ischemia model in rats. METHODS: In a middle cerebral artery occlusion model in rats, infarction is confined to the cerebral cortex. The infarct was delineated by triphenyltetrazolium chloride stain and, in selected samples, by hematoxylin and eosin stain. We determined infarct size at different times after the ischemic insult (6 hours to 7 days) in relation to the evolution of brain edema by the direct measurement of infarct volume. Indirect measurement to reduce the effect of edema on infarct volume was also conducted in the same brain samples. RESULTS: Direct measurement showed that infarct volume fluctuated with the evolution of brain edema (one-way analysis of variance, p < 0.0001). Infarct volume determined by indirect measurement was independent of the extent of brain edema and remained stable from 6 hours to 3 days after ischemia. There was a good correlation between triphenyltetrazolium chloride and hematoxylin and eosin stains in delineating infarct volume with both direct and indirect measurement. CONCLUSION: Traditional direct measurement of infarct volume is associated with an overestimation of infarct volume during the development of brain edema in the first 3 days after ischemia. This artifact can be reduced with indirect measurement, which is based on noninfarcted cortex volume.

Animals↗
PubMed1993

Enhanced glucose metabolism and respiratory burst in peritoneal macrophages from spontaneously diabetic BB rats.

Glucose metabolism and respiratory burst were studied in vitro in resident peritoneal macrophages from non-diabetes-prone BB, spontaneously diabetic BB, diabetes-prone BB, and STZ-induced diabetic BBn rats, in the presence or absence of phorbol myristate acetate plus ionomycin. Glycolysis and pentose phosphate pathway activity were increased in BBd compared with BBn cells. PMA plus IONO did not influence glycolysis in BBn macrophages and slightly decreased it in BBd macrophages. In contrast, PMA plus IONO increased the pentose phosphate pathway activity in BBn and BBd macrophages with a much greater increase in BBd cells. The release of O2- was greater in BBd than BBn cells; PMA plus IONO also induced a much greater release of O2- in BBd cells. H2O2 release was undetectable in unstimulated BBn cells, and stimulation by PMA plus IONO caused a small incremental release. In contrast, the release of H2O2 was measurable in unstimulated cells and further increased by 50% in BBd cells with PMA-plus-IONO stimulation. The release of O2- and H2O2 was increased in macrophages from 75-day-old BBdp rats but not in 50-day-old BBdp rats, compared with age-matched BBn rats. No differences were observed in either glucose metabolism or release of O2- and H2O2 between BBn and STZ-BBn cells in the absence or presence of PMA plus IONO. These data suggest that enhanced oxidative metabolism in BBd macrophages is unlikely to be attributable to diabetes per se.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1993

Child growth, nutritional status, and schistosomiasis japonica in Jiangxi, People's Republic of China.

The association between schistosomiasis japonica and nutritional status and child growth was studied cross-sectionally in 239 males and females (age range 4-19.9 years) residing in Jishan Island in Po Yang Lake in an endemic region of Jiangxi, China. The presence of Schistosoma japonicum eggs in Kato stool smears and the intensity of schistosomiasis as assessed by quantitative egg count were determined, as were the presence of hookworm, Ascaris, and Trichuris eggs. Anthropometric measures included stature, weight, weight-for-height, upper arm muscle area, and the sum of triceps and subscapular skinfold thickness. The association between schistosomiasis and nutritional status and growth was analyzed with multivariable models adjusted for the influence of age, age2, and polyparasitism. The prevalence of schistosomiasis was approximately 70% in both males and females. Current schistosomiasis and its intensity were significantly related to reduced stature, weight, weight-for-height, and the sum of skinfolds (all P < 0.01) in females across the entire age-span. The greatest age-specific differences were during adolescence in females: 4 cm in height and 5 kg in weight. In males, intensity of schistosomiasis was related (P < 0.03) only to the sum of skinfolds. The cross-sectional associations between anthropometric reductions and schistosomiasis japonica in childhood and adolescence indicate a strong independent effect of infection on malnutrition and growth in this population from a highly endemic region of China.

Adolescent↗
PubMed1993

Antiplatelet granule membrane protein (GMP-140) autoantibodies detected in plasma from patients with idiopathic thrombocytopenic purpura.

Plasma from 92 patients with idiopathic thrombocytopenic purpura (ITP) was tested for autoantibodies against granule membrane protein 140 (GMP-140) using an antigen specific immunoassay. Results showed that autoantibodies to GMP-140 existed in 17 of these patients (18.5%). Incubation of patient plasma with purified GMP-140, immobilized on nitrocellulose strips by SDS-PAGE and Western blotting, revealed a staining band at the level of GMP-140 in two of 8 plasmas. Autoantibodies to GMP-140 often coexisted with other autoantibodies, in particular towards GP Ib/IX (3 cases), GP IIb-IIIa (5 cases) or both (3 cases). This study provides direct evidence for the presence of anti-platelet GMP-140 autoantibodies in some patients with ITP.

Adult↗
PubMed1993

Cytochrome bd biosynthesis in Escherichia coli: the sequences of the cydC and cydD genes suggest that they encode the components of an ABC membrane transporter.

At least four genes are known to affect formation of the cytochrome bd-type terminal oxidase of Escherichia coli. In addition to the genes (cydA and cydB) encoding the two constituent subunits of this complex, a further two genes (cydC and cydD) map near 19 min on the E. coli chromosome. We report here the cloning of both genes on a 5.3 kb ClaI-HindIII restriction fragment, which, when used to transform either a cydC or cydD mutant, restored the ability of these mutants to grow on a selective medium containing azide and zinc ions and also restored the spectral signals associated with the cytochrome components of the oxidase complex. A subcloned 1.8 kb DdeI fragment similarly restored growth and cytochrome content of a cydD mutant, but not a cydC mutant. The complete nucleotide sequence of the ClaI-HindIII fragment reveals three open reading frames, one being trxB (19.3 min on the E. coli chromosome map, encoding thioredoxin reductase), confirming the mapping position of cydD previously established by P1-mediated transduction. Two ORFs identified by complementation experiments as cydD and cydC encode proteins with predicted molecular masses, respectively, of 65,103 and 62,946 Da. The hydropathy profile of each protein reveals an N-terminal hydrophobic domain and a C-terminal hydrophilic domain containing a putative nucleotide-binding site. The gene products probably constitute an ABC (ATP-binding cassette) family membrane transporter, the function of which is necessary for the formation of the cytochrome bd quinol oxidase. The CydDC system appears to be the first prokaryotic example of a heterodimeric ABC transport system in which each polypeptide contains both hydrophobic and ATP-binding domains.

ATP-Binding Cassette Transporters↗
PubMed1993

Isoproterenol/tannin-dependent R15 expression in transgenic mice is mediated by an upstream parotid control region.

Transgenic mice were used to locate the cis-acting DNA elements that are essential for tissue-specific and inducible expression of the rat proline-rich protein gene, R15. Chimeric genes with up to 10 kb of R15 5'-flanking region fused to chloramphenicol acetyltransferase (CAT) or polyomaviral large T-antigen (PyLT) reporter genes were tested. Our results demonstrate that (1) the isoproterenol/tannin-inducible, parotid-specific transgene expression requires an upstream cis-regulatory domain, namely the parotid control region, which extends from -6 to -1.7 kb of the R15 gene; (2) this parotid control region functions with a heterologous promoter and is indispensable for achieving a reproducible chromosomal position-independent transgene expression; (3) deletion of the R15 5'-flanking region up to -1.7 kb results in a pleiotropic effect on the transgene expression, which includes ectopic (nonsalivary) reporter expression and lack of inducibility by either the beta-agonist isoproterenol or dietary tannin stimulation; (4) when the -10 to -6 kb region from the R15 gene is deleted in the construct, the inducible expression in the parotid glands of the transgenic mice decreases by over 30-fold, but position-independent and tissue-specific transgene expression is retained. Moreover, the mechanism of induction by either catecholamine isoproterenol or dietary tannin appears to be through a beta 1-adrenergic receptor-mediated pathway for both normal (non-transgenic) and transgenic animals.

Animals↗
PubMed1993

[Immunological diagnosis of light chain disease--analysis of 11 cases found in Fujian Province].

This paper reports 11 cases of light chain disease (LCD) sequentially found in several coastal cities of Fujian Province. Immunological classification of this group of LCD was as follows: 6 belonged to lambda type, 4 were kappa type, and 1 was double LCD. We found that LCD was common in Fujian next only to MM of IgG class and accounted for 20% of the total 55 MM cases found in recent years. Several important points should be stressed when making immunological diagnosis of LCD. 1) It is well known that in most patients with LCD, M protein or Bence Jones proteinemia (BJPemia) is not detectable by conventional electrophoresis. Our studies show that running serum protein along with urinary BJP on the same one gel plate can allow for the recognition of small and faint band (s) of free light chain in serum, and also provides a rapid and sensitive method (immunofixation) to directly detect urinary light chains. 2) The concurrent presence of albumin with BJP in urine may interfere with the routine BJP test and lead to misdiagnosis. 3) As a result of the molecular seiving effect, the presence of light chain polymers in high BJP urine may lead to the presence of several parallel bands on the BJP gel electrophoretic spectrum, 4) Determination of light chain in urine is essential for final immunological diagnosis of LCD, but care should be taken, since many patients with other immunological types of MM may have a positive BJP test.

Bence Jones Protein↗
PubMed1993

[Effects of antihypertensive factor on cardiac function in spontaneously hypertensive rats].

In this study, we observed the effects of erythrocytic AHF from normotensive human subjects on heart function of stroke prone SHR (SHRsp) in order to investigate the antihypertensive mechanism of AHF. The results showed that AHF significantly decreased the heart rate (HR), left ventricular end systolic pressure (LVESP), and magnitude of +/- LVdP/dtmax, but had no effect on Wistar Kyoto (WKY) rats, indicating that AHF has negative chronotropic and inotropic action on SHRsp hearts. AHF also lowered the contraction amplitude and resting tension in isolated SHRsp hearts, but had no effect on HR and blood flow of the coronary artery, indicating that AHF exerts negative inotropic action on isolated SHRsp hearts. The results suggest that the antihypertensive mechanism of AHF may be related to its ability to decrease cardiac function in hypertensive rats.

Animals↗
PubMed1993

MultiLink--an intermediary system for multi-database access.

The design and implementation is described of MultiLink, a desktop system for direct enduser access to remote bibliographic information. The system is an application of a client-server technique based on a campuswide network, with the objective to assist end-users to accomplish the information--retrieval process by capturing knowledge and expertise for searches in query formulations. MultiLink, via intelligent interfaces, allows users to access several dozens of bibliographic databases. The application integrates regional, national and international resources, and brings library services to the user's desktop level.

Databases, Bibliographic↗
PubMed1992

Protection of neuro-2a cells against calcium ionophore cytotoxicity by gangliosides.

Gangliosides are known to assert both neuritogenic and neuroprotective effects when applied to a variety of neuroblastoma and primary neuronal cultures. We have developed a model employing Neuro-2a neuroblastoma cells with Ca2+ ionophore A23187 as neurotoxic agent causing neurite retraction and eventual cell death. Gangliosides attenuated the toxicity of this substance, increasing both cell survival and neurite stability. In one series of experiments, cells were exposed to A23187 for 24 hr and then incubated in fresh medium (washout) for 18 hr; gangliosides were present at varying times. The paradigm in which cells were only preincubated (2 hr) with ganglioside provided no benefit, nor did incubation of the cells in both ionophore and ganglioside during the 24-hr exposure period. Significant protection was achieved by exposing the cells to ganglioside after washout of A23187, or continuously throughout the whole period. Bovine brain ganglioside mixture and the four major components (GM1, GD1a, GD1b, GT1b) applied individually were all effective. By contrast, GM3 and GM1-alcohol, a neutral derivative of GM1, provided little or no protection. Dichlorobenzamil, an inhibitor of the Na(+)-Ca2+ exchanger, tended to block the neurite stabilizing effect of gangliosides, suggesting that the mechanism might involve potentiation of this antiporter.

Animals↗
PubMed1992

NPPB block of Ca(++)-activated Cl- currents in Xenopus oocytes.

NPPB (5-nitro-2-(3-phenylpropylamino)-benzoate), a member of the novel class of Cl- channel blockers related to diphenylamine-2-carboxylate, was studied for its effect on the Ca(++)-activated Cl- current (ICl(Ca)) in frog (Xenopus laevis) oocytes. ICl(Ca) was activated by bath application of 5 mM Ca++ to oocytes that had been Ca++ permeabilized with the Ca++ ionophore A23187. In order to prevent the inactivation of ICl(Ca) that occurs with repetitive applications of Ca++, oocytes were also treated with H-7 (1,5-isoquinolinesulfonyl-1,2 methylpiperazine), an inhibitor of protein kinases. NPPB reversibly blocked both the fast transient (Ifast) and slow (Islow) components of ICl(Ca) with inhibition constants of 22 microM and 68 microM, respectively. NPPB block of ICl(Ca) was voltage dependent and potentiated by depolarization of the oocyte membrane. Our results indicate that NPPB is a potent blocker of the oocyte endogenous ICl(Ca), and may prove useful in the study of exogenously expressed Cl channels.

Animals↗
PubMed1992

Porcine endometrial epithelial cells immortalized by transfection with origin-defective, temperature-sensitive simian virus 40 DNA.

The purpose of this study was to immortalize porcine endometrial cells and to characterize the transformed cells. Primary porcine endometrial cells were transfected with the plasmid vector (pmk16) containing SV40 DNA using a liposome-mediated method. The viral DNA was from a replication-defective, origin-minus, temperature-sensitive mutant strain (A58). One clone, designated PE-1, has been propagated for over 120 passages. PE-1 cells grown at 33C (33C cells) exhibit spindle-shaped morphology; when cultured at 40C (40C cells), they took on a polygonal or spherical shape. Morphology of 40C cells returned to the spindle shape after culture flasks were shifted back to 33C. During a 2-week period, 33C cells propagated approximately 30-fold faster than 40C cells, whereas protein concentration was higher in 40C cells. Southern blot analysis of PE-1 cells demonstrated successful integration of the ts-SV40 DNA sequence into the porcine endometrial cells, possibly at multiple sites. The presence of cytokeratin on PE-1 cell membranes was shown by immunocytochemical studies, suggesting that the PE-1 cell clone was of epithelial origin. Reverse phase (RP)-HPLC analysis of PE-1 cell extract indicated that the majority of immunoreactive beta-endorphin (ir-BEND) eluted with a hydrophobicity similar to that of synthetic BEND and alpha-N-acetylated BEND (Nac-BEND). These results demonstrate that a porcine endometrial cell line has been established, and that this cell line possesses characteristics of temperature sensitivity in cell morphology, growth rate, and protein synthesis.

Animals↗
PubMed1992

Enhanced glutamine and glucose metabolism in cultured rat splenocytes stimulated by phorbol myristate acetate plus ionomycin.

Metabolism of glutamine and glucose was studied in normal rat splenocytes cultured for 48 hours in the presence and absence of a mixture of the mitogens, phorbol myristate acetate (PMA) + ionomycin (Iono). 3H-Thymidine uptake by splenocytes was stimulated more than 500-fold by PMA + Iono. After culture, cells were incubated for 2 hours in the presence of either 2 mmol/L [U-14C]glutamine +/- 5 mmol/L glucose or 5 mmol/L [U-14C]glucose +/- 2 mmol/L glutamine in Krebs-Ringer HEPES buffer. Glutamine was metabolized mainly to ammonia, glutamate, aspartate, and CO2, and these products were all increased (P less than .01) by twofold to 2.5-fold in stimulated cells. Glucose was metabolized mainly to lactate and, to a lesser extent, to pyruvate and CO2. Lactate production from glucose was increased (P less than .01) by 2.4-fold in stimulated cells, without changes in pyruvate or CO2 production. In unstimulated, cultured splenocytes, glutamine was not quantitatively as important as glucose in the provision of adenosine triphosphate (ATP), as calculated on the basis of measured metabolites. However, in stimulated cells, glutamine became a much more important energy substrate, providing similar amounts of ATP to those from glucose. The oxidation of glutamine via the Krebs cycle was the major pathway for glutamine-derived ATP production, while lactate production from glucose accounted for the major part of glucose-derived ATP in PMA+Iono-stimulated splenocytes. Thus, we suggest glutamine plays a dual metabolic role in these cells, as both an important fuel and an essential source of carbon and nitrogen precursors for biosynthetic processes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1992

Inhibition by germanium oxide of the mutagenicity of cadmium chloride in various genotoxicity assays.

The effects of germanium oxide on the genotoxicity of cadmium chloride were investigated. The incorporation of [3H]thymidine into testicular DNA was inhibited in mice injected ip with 1.35, 1.80 or 2.70 mg cadmium chloride/kg body weight. Germanium oxide (0.05 or 0.1 mg/kg body weight, sc) alone did not affect [3H]thymidine incorporation into testicular DNA but 0.05 mg germanium oxide/kg antagonized the inhibitory effect of 1.35 mg cadmium chloride/kg. However, combinations of the other doses of the two compounds did not show statistically significant antagonistic effects. Cadmium chloride significantly increased the frequencies of micronucleus formation in polychromatic erythrocytes, and of chromosome aberrations in the bone marrow of mice treated with 0.7, 1.4 or 2.7 mg/kg body weight, in a dose-related manner. These effects were inhibited by germanium oxide at doses of 0.1 or 0.5 mg/kg body weight, although germanium oxide alone did not affect micronucleus formation or the chromosome aberration rate. Cadmium chloride produced a dose-related increase in the frequency of sister chromatid exchanges in cultured human lymphocytes at concentrations of 5, 10 or 50 mumol. This effect was also inhibited by germanium oxide (0.05 or 0.1 mumol), although germanium oxide alone had no effect. There was a dose-related increase in the frequency of sperms with abnormal head morphologies from mice treated with 0.6, 1.1 or 2.2 mg cadmium chloride/kg body weight and this too was antagonized by the injection of germanium oxide (0.1 or 0.5 mg/kg body weight). Germanium oxide alone did not affect the frequency of sperm-head abnormalities.

Animals↗