Biomedical subjects

G F Wang

Publications and source records attributed to G F Wang.

At least 37 records · Page 2Linked to original sources

PubMed1996

Vascular hyporesponsiveness in aorta from portal hypertensive rats: possible sites of involvement.

Vascular hyporesponsiveness in portal hypertension has been proposed to be due to postreceptor defect. The present study was aimed to investigate possible sites of involvement in such hyporesponsiveness. Portal hypertension was induced by partial portal vein ligation (PVL). Concentration-response curves to KCI and phenylephrine in both groups showed that the Emax values were significantly lower in the PVL group. The EC50 values were not different between the two groups. In Ca++ free condition, phenylephrine induced a phasic contraction, which was significantly smaller in the aorta from PVL rats. Cumulative readdition of CaCl2 (1.0-2.5 mM) induced tension increases, which were all significantly lower in the PVL group. Basal contents of [3H]inositol phosphates in the aorta were similar between the two groups. Phenylephrine induced concentration-dependent increase of [3H]inositol phosphates in the aorta from both groups. The responses at 10(-8), 10(-7), 10(-6) and 10(-5) M were significantly smaller in the PVL group than in the sham-operated group. Both okadaic acid and phorbol 12,13-dibutyrate induced slowly developing contractile responses in the aorta. The responses were similar between the two groups at all time points. Our results suggested that in the aorta from PVL rats, vascular hyporesponsiveness was observed, together with decreased contractile responses due to: voltage- and receptor-dependent calcium influx as well as intracellular calcium release, and decreased receptor-coupled inositol phosphate formation. Contractile responses due to activation of protein kinase C or phosphatase inhibition were not impaired.

Animals↗

PubMed1996

[A novel conservative structure found in the carp mitochondrial tRNA(phe) gene].

A nucleotide sequence for the tRNA(phe) gene of Carp mitochondria was determined. Sequence data comparisons made among the whale, human, Xenopus laevis, bovine, mouse, chicken and carp, showed that a novel conservative structure was found in the D. stem (dihydrouridine stem), which was known had variant nucleotides in any other vertebrate mitochondrial tRNA and cytoplasmic tRNA genes. This conservative structures contains 13 bp. When we compared the front 7 bp of the conservative structure with the eukaryotic RNA Pol III recognitive A domain, we found these two kinds of different species had partly homologue. As the mitochondrial tRNA(phe) gene is located between the displacement loop and mitochondrial rRNA gene, we inferred that the novel conservative structure might have some extra interesting functions.

Animals↗

PubMed1995

Fructus aurantii reduced portal pressure in portal hypertensive rats.

The purpose of this study was to investigate the effects of Fructus Aurantii (the unripe fruits of Citrus aurantium L.) on portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation (PVL) in Sprague-Dawley rats. Sham-operated (Sham) rats served as controls. Hemodynamic and in vitro contractile studies were performed at 14 days after surgery. Both the aqueous extract of Fructus Aurantii and synephrine, one of its purified principles with pressor activity, were infused into the conscious PVL and Sham rats via a syringe pump. Fructus Aurantii (1.25, 2.5, & 5.0 mg/kg/min) dose-dependently reduced portal pressure in PVL and Sham rats, with the percentage change in portal pressure more pronounced in PVL rats. Mean arterial pressure was dose-dependently elevated by Fructus Aurantii. Synephrine (0.095, 0.19, & 0.38 mg/kg/min) also dose-dependently reduced portal pressure and elevated mean arterial pressure in PVL and Sham rats. Fructus Aurantii (2.8-280 micrograms/ml) induced dose-dependent contractile responses mainly in aorta and mesenteric artery, but little response in portal vein. The results showed that Fructus Aurantii infusion reduced portal pressure, possibly by way of arterial vasoconstriction.

Animals↗

PubMed1995

Ceruloplasmin or fibronectin synergism with quartz dust on stimulating collagen gene transcription in human 2BS fibroblast.

Human alpha 1(I), alpha 2(I) and alpha 1(III) cDNA probes and RNA dot hybridization were employed to quantitate collagen mRNA changes after adding silica dust into the media of human 2BS fibroblasts. At all dosages used (100, 200, 500 and 1000 micrograms), the alpha 1(I), alpha 2(I) and alpha 1(III) mRNA levels increased one day after dusting. At the same dosage of silica (100 micrograms), alpha 1(III) mRNA increased earlier than type I collagen mRNA did. The type I and type III collagen mRNA contents in the experimental groups were higher than those in control on days 3, 5, 7 and 9. The effect of ceruloplasmin (Cp) and fibronectin (Fn) on collagen mRNA synthesis was also studied, after adding silica dust, Cp or Fn into the media of human 2BS fibroblast. The results showed that Cp and Fn have stimulating effect on collagen mRNA production. When both Cp and silica dust were added into cell culture media, the collagen mRNA level was increased more than those of adding either Cp or silica dust alone. Similar situations were found for Fn. Cp (or Fn) synergism with silica dust on stimulating transcription of human collagen gene was suggested.

Cells, Cultured↗

PubMed1994

Daidzin, an antioxidant isoflavonoid, decreases blood alcohol levels and shortens sleep time induced by ethanol intoxication.

The extract from an edible vine, Pueraria lebata, has been reported to be efficacious in lessening alcohol intoxication. In this study, we have tested the efficacy of one of the major components, daidzin, from this plant extract. When ethanol (40% solution, 3 g/kg body weight) was given to fasted rats intragastrically, blood alcohol concentration (BAC) peaked at 30 min after alcohol ingestion and reached 1.77 +/- 0.14 mg/ml (mean values +/- SD, n = 6). If daidzin (30 mg/kg) was mixed with the ethanol solution and given to animals intragastrically, BAC was found to peak at 90 min after alcohol ingestion and reached only 1.20 +/- 0.30 mg/ml (n = 6) (p < 0.05 vs. controls). The ability of daidzin to delay and decrease peak BAC level after ethanol ingestion was also observed in fed animals. In both fasted and fed rats given alcohol without daidzin, BAC quickly declined after reaching its peak at 30 min. By contrast, BAC levels receded more slowly if daidzin was also fed to the animals. Daidzin showed a chronic effect. Rats fed daidzin for 7 days before ethanol challenge, but not on the day of challenge, also produced lower and later peak BAC levels. Interestingly, daidzin, whether fed to rats only once or chronically for 7 days, did not significantly alter activities of either alcohol dehydrogenase or mitochondrial aldehyde dehydrogenase in the liver. Further experiments demonstrated that daidzin shortened sleep time for rats receiving ethanol intragastrically (7 g/kg) but not intraperitoneally (2 g/kg). To test whether daidzin delayed stomach-emptying, [14C]polyethylene glycol was mixed with ethanol and fed to rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Dehydrogenase↗

PubMed1993

The primary structure of branched-chain alpha-oxo acid dehydrogenase from Bacillus subtilis and its similarity to other alpha-oxo acid dehydrogenases.

The bfmB mutant of Bacillus subtilis requires branched short-chain carboxylic acids for growth because the organism is known to be defective in branched-chain alpha-oxo acid dehydrogenase. The DNA in the region of bfmB has now been cloned and sequenced, and the gene has been analyzed. The results show that there are three open reading frames in the area, each of which is preceded by a putative ribosome binding site, and the last of which is followed by a putative transcription termination site with inverted repeats. The amino acid sequences deduced by analysis of the reading frames are highly similar (with 32-49% identity) to the E1 alpha, El beta and E2 components of pyruvate, 2-oxoglutarate and branched-chain alpha-oxo acid dehydrogenases from different sources. The thiamin diphosphate binding, putative subunit interaction and phosphorylation sites of the E1 alpha of four reported branched-chain alpha-oxo acid dehydrogenases from different sources are very similar to those of the first open reading frame (E1 alpha) of bfmB. A similar result is also obtained with the lipoyl-binding site (lysine) and its domain of the E2 component of alpha-oxo acid dehydrogenases from different sources. The present data, along with the reported biochemical data, lead to the conclusion that bfmB encodes a branched-chain alpha-oxo acid dehydrogenase, which is composed of E1 alpha, E1 beta and E2 genes. This organization is identical to that of the 2-oxoglutarate dehydrogenase in B. subtilis.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗

PubMed1993

Radioimmunotherapy for unresectable hepatocellular carcinoma using 131I-Hepama-1 mAb: preliminary results.

Twenty-three patients with surgically verified unresectable hepatocellular carcinoma (HCC) have been treated by intrahepatic arterial administration of 131I-labeled anti-HCC monoclonal antibody (Hepama-1) combined with hepatic artery ligation. Radioimmunoimaging demonstrated that the median tumor/liver ratio was 2.1 (1.1-3.6) at day 5. A decline in alpha-fetoprotein level and shrinkage of tumor were observed in 75% (12/16) and 78% (18/23) of patients respectively. Sequential resection was done in 11 patients (48%) after treatment. The surgical specimens revealed massive necrosis of tumor, but residual cancer cells were found at the edge of the specimens. Anti-antibody was determined in 43% (10/23) of patients 2-4 weeks after the administration of 131I-Hepama-1 mAb. No marked toxic effects were noted. It is suggested that 131I-Hepama-1 mAb might be of value as one of the multimodality treatments for unresectable HCC.

Animals↗

PubMed1993

[Structure analysis of the mitochondrial tRNA(Cys) gene and the original region of light-strand replication from carp].

In this study, we have determined the nucleotide sequences of the cysteine tRNA gene and the original region of light-strand replication from carp (Cyprinus carpio L.) mitochondrion, which were further represented respectively in cloverleaf secondary structure and stem loop structure. By comparing the nucleotide sequences of 5 vertebrate tRNA(Cys) genes, it is found that carp mitochondrial tRNA(Cys) gene have many unusual structural features differing from those of cytoplasmic tRNA(Cys) gene. The carp mitochondrial original region of light-strand replication consists of 36 bases which include 11 base pairs in its stem and 14 bases in its loop. By making a comparison between the nucleotide sequences of the carp original region of light-strand replication and those of other 10 vertebrates, it is further found that stem sequence of carp is very conservative while loop sequence is very variable. This result indicates that stem structure may play an important role in the replication of light strand.

Animals↗

PubMed1993

[Determination of six main components in compound theophylline tablet by convolution curve method after prior separation by column partition chromatography].

On a partition chromatographic column in which the support is Kieselguhr and the stationary phase is sulfuric acid solution (2 mol/L), three components of compound theophylline tablet were simultaneously eluted by chloroform and three other components were simultaneously eluted by ammonia-saturated chloroform. The two mixtures were determined by computer-aided convolution curve method separately. The corresponding average recovery and relative standard deviation of the six components were as follows: 101.6, 1.46% for caffeine; 99.7, 0.10% for phenacetin; 100.9, 1.31% for phenobarbitone; 100.2, 0.81% for theophylline; 99.9, 0.81% for theobromine and 100.8, 0.48% for aminopyrine.

Aminopyrine↗

PubMed1992

[Oxidative phosphorylation of liver mitochondria in Oncomelania snail].

Oxidative phosphorylation of liver mitochondria in Oncomelania snail was separately detected by using oxygen electrode and spectrophotometer. ADP increased oxidative reaction of liver mitochondria from 0.187 to 0.318 mumol O2/mg protein.20 min. When certain substrates of citric acid cycle were added to liver mitochondria of Oncomelania snail, we found that oxidative phosphorylation increased to 0.353-0.444 mumol O2/mg protein.20 min. ATPase was detected in the liver of Oncomelania snail. The oxidative phosphorylation of mitochondria in Oncomelania snail could be markedly inhibited by DNP and molluscicide bromoacetamide, but the latter didn't show the inhibition of ATPase. (Figs. 1,2).

2,4-Dinitrophenol↗

PubMed1992

Structure of the mitochondrial URFA6L gene and tRNA(Lys) gene from CARP.

The carp mitochondrial URFA6L gene consists of 165 base pairs. The overall structural organization of the gene is very similar to that of the Xenopus URFA6L gene. Their nucleotide sequences exhibit 68% homology. The carp URFA6L gene encodes a protein of 54 amino acids. The amino acid composition of the protein is unusual because almost half of the residues consist of 5 hydrophobic amino acids (proline, tryptophan, leucine, isoleucine and tyrosine). A comparison between the amino acid sequences of 5 vertebrate URFA6L proteins and the yeast ATPase 8 showed that they have weak but very important common structural features, suggesting that the vertebrate URFA6L proteins may function as ATPase8. The nucleotide sequence of the lysine tRNA gene from carp has been determined and represented in clover-leaf secondary structure. Similar to amphibian and mammalian mitochondrial tRNA(Lys) genes, the carp mitochondrial tRNA(Lys) gene also has some unusual structural features as compared with its cytoplasmic counterpart. A comparison between the nucleotide sequences of the tRNA(Lys) gene from 7 vertebrates showed that the most conservative portions are the anticodon loop, nucleotides 8 and 9, the variable loop, the anticodon stem and the aminoacyl stem. The least conservative portions are the D-loop and the T-loop. These structural features may show that the mitochondrial tRNA(Lys) has a different interaction with mitochondrial ribosome.

Amino Acid Sequence↗

PubMed1991

Mode of action of the molluscicide bromoacetamide.

1. Uptake of bromoacetamide was found to be upgraded with exposure time (6, 12, 24 hr) and drug concentration (0.1, 0.5, 1.0 ppm). 2. Bromoacetamide was also absorbed by carp and mice, but drug concentration was markedly lower than in snails. Drug clearance from carp as well as from mice is more rapid than that of snails. 3. The ultrastructure of hepatopancreas cells are markedly influenced by bromoacetamide, including swelling of mitochondria and splitting of cristae. This finding is correlative in a decrease in action of enzymes located in mitochondria (ornithine carbamyl-transferase, citric acid synthase). 4. Oxygen uptake and glucose uptake, as well as urea excretion, are reduced and glycogen reserve are decreased.

Acetamides↗

PubMed1991

[Distribution of bromo[methylene-3H]acetamide in Oncomelania snails, carps, and mice].

Bromoacetamide show a high molluscicidal effect, low toxicity to fish and good solubility in water. It is a promising molluscicide. The present paper reported the distribution of bromo[methylene-3H]acetamide in Oncomelania snails, carps, and mice. Radioactivity in animals was measured by liquid scintillation counting. In Oncomelania snails the radioactivity gradually increased with exposure time and drug concentration. The highest level was found in the head-foot, reaching 12.5 x 10(3) dpm.mg-1 after exposure to the drug for 24 h, whereas the levels in liver and other tissue were 3.0 x 10(3) and 3.8 x 10(3) dpm.mg-1 respectively. Carps absorbed bromo[methylene-3H] acetamide similarly as in Oncomelania snails, but the levels in tissues were less than those in Oncomelania snails. Bromo[methylene-3H]acetamide 0.5 ml (1.4 mumol.L-1) was given ig to mice. Blood samples of 3 mice were collected at 0.5, 1, 3, 6, 12, 24 and 96 h after ig. The peak levels was found within 12 h and then declined gradually.

Acetamides↗

PubMed1991

Indoor air pollution in four cities in China.

The study reports the investigation of indoor air pollution carried out in four cities in China (Chengde, Shanghai, Shenyang and Wuhan). The concentrations of RP, SO2, CO and NO2 were measured in kitchens and bedrooms, both in summer and in winter. The results showed that indoor air pollution, as measured by RP, SO2, CO, was heavy when coal was used as domestic fuel. This was particularly severe in winter. For example, the concentrations of SO2 in homes with coal stoves were more than 10 times higher than those in homes with gas or LPG in Shanghai. The concentrations of pollutants in kitchens were higher than those in bedrooms. The source of pollutants was fuel combustion from kitchen. The highest concentrations in kitchen could reach 665 micrograms/m3 (RP), 860 micrograms/m3 (SO2) and 14.07 mg/m3 (CO). The concentrations in bedrooms were up to 270 micrograms/m3, 502 micrograms/m3, and 13.67mg/m3, respectively.

Air Pollution, Indoor↗

PubMed1991

Phosphoramidon-sensitive endothelin converting enzyme in rat lung.

A neutral proteinase with endothelin (ET)-1 converting activity was identified in cytosol and membrane fractions prepared from rat lung, in a ratio of 1:4, respectively. The membrane-bound proteinase was solubilized by 0.5% 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) with an increase in specific activity, and then was characterized. The solubilized proteinase was capable of converting big ET-1 to ET-1 with an optimum pH of 6.5, and the conversion was dose-dependently suppressed by phosphoramidon (IC50 = 0.5 microM). The molecular mass of the proteinase was estimated to be about 500 kDa by gel filtration in the presence of 0.5% CHAPS. These results indicate that rat lung contains a phosphoramidon-sensitive neutral proteinase catalyzing conversion of big ET-1 to ET-1. The proteinase may be involved in the biosynthetic pathway of ET-1 in the lung and/or the conversion of circulating big ET-1.

Animals↗

PubMed1991

[Molecular cloning of alpha-amylase gene from Bacillus megaterium and its expression in Bacillus subtilis].

Using Bacteriophage lambda and plasmid pAT153 and pNQ122 as vectors, alpha-Amylase gene from B. megaterium has been cloned into both hosts of E. coli and B. subtilis. Expression level of the gene is 250 times higher than B. megaterium when it resides in B. subtilis. The enzyme produced by B. subtilis harboring the hybrid plasmid can digest amylase into maltose and maltotriose at first, then turn them to maltose and glucose, as incubation time extended. It also can digest maltotriose to maltose and glucose. As a control, the extracts from the broth of recipient strain have no detectable amylase activities. Therefore the enzyme coded by this gene is defined as saccharifying type alpha-amylase. Its molecular weight is about 58,000 daltons.

Bacillus megaterium↗

PubMed1990

Elevation of individual serum bile acids on exposure to trichloroethylene or alpha-naphthylisothiocyanate.

Rats were treated with trichloroethylene via intraperitoneal (ip) injection or inhalation, or with ip alpha-naphthylisothiocyanate (ANIT). Serum samples were assayed for indices of liver injury including alanine aminotransferase (ALT), sorbitol dehydrogenase (SDH), alkaline phosphatase (AP), and bilirubin. Liver from some rats was examined for histological appearance. These data were compared to levels of individual serum bile acids (SBA) determined by high-performance liquid chromatography. Trichloroethylene and ANIT, each at their highest dose only, caused elevations in ALT, but not SDH or AP. The highest dose of ANIT also caused elevated serum bilirubin and cholangitis in the liver. SBA were also elevated in response to both trichloroethylene and ANIT, but at doses below those at which other parameters of liver function were increased. For both chemicals, taurocholic acid was the most sensitive of the bile acids assayed, being elevated at the lowest doses tested of 10 mumols/kg for trichloroethylene and 5 mumols/kg for ANIT. As the doses were raised more of the individual bile acids showed increases. On exposure to trichloroethylene via inhalation taurocholic acid was one of two SBA to show elevation. Thus, both trichloroethylene and ANIT cause elevation in SBA at doses well below those which cause an increase in standard indicators of liver dysfunction. This suggests that SBA and perhaps taurocholic acid, in particular, may provide a sensitive tool for studying hepatobiliary effects of chemicals.

1-Naphthylisothiocyanate↗

PubMed1990

Paradoxical effect of hypothermia on survival of lesioned and uninjured mammalian spinal neurons.

Survival of cultured spinal neurons 2 h after dendrotomy increased significantly when the temperature was reduced to 17 degrees C or 7 degrees C. Survival of lesioned neurons maintained at 17 degrees C for 2 h and then at 37 degrees C for 22 h was still significantly higher than survival of neurons maintained at 37 degrees C for 24 h. Below 17 degrees C both lesioned and uninjured neurons swelled. Upon rewarming to 37 degrees C, many swollen neurons died. Ketamine prevented hypothermic swelling and neuronal death.

Animals↗