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Biomedical subjects

W Shen

Publications and source records attributed to W Shen.

At least 199 records · Page 11Linked to original sources
PubMed1995

Clinical significance of complete left bundle branch block in dilated cardiomyopathy.

Clinical, electrocardiographic and echocardiographic findings in 64 patients with dilated cardiomyopathy were restrospectively studied. Compared with 51 patients without complete left bundle branch block (CLBBB), 13 patients with CLBBB had higher New York Heart Association (NYHA) functional class (P < 0.05), increased left ventricular end-diastolic and end-systolic diameters (P < 0.002) and myocardial mass (P < 0.02), severe mitral regurgitation (P < 0.01) and higher mortality rate (P < 0.04). Multivariate stepwise regression analysis revealed that the presence of CLBBB was an independent prognostic factor for patients with dilated cardiomyopathy.

Adult↗
PubMed1995

Abnormal left ventricular systolic and diastolic functional response to isometric exercise in idiopathic dilated cardiomyopathy: beneficial effect of captopril.

In 19 patients with idiopathic dilated cardiomyopathy and symptoms of congestive heart failure, left ventricular (LV) systolic performance and diastolic velocity profiles were assessed by two- dimensional echocardiography and pulsed wave Doppler at rest and during handgrip exercise before and ninety minutes after administration of captopril (mean dose 25 +/- 12mg; range 12.5-50mg). Although heart rate and blood pressure increased similarly during handgrip exercise before and after captopril treatment, both were lower with handgrip exercise during captopril treatment. The results from this study indicated that acute angiotension converting enzyme inhibition with captopril reduces preload and afterload and ameliorates handgrip exercise-induced LV systolic and diastolic filling dysfunction in patients with congestive heart failure secondary to idiopathic dilated cardiomyopathy.

Adult↗
PubMed1994

Purification of collagen-binding proteins of Lactobacillus reuteri NCIB 11951.

Collagen type-I-binding proteins of Lactobacillus reuteri NCIB 11951 were purified. The cell surface proteins were affinity purified on collagen Sepharose and eluted with an NaCl gradient. Two protein bands were eluted from the column (29 kDa and 31 kDa), and both bound radio-labeled collagen type I. Rabbit antisera raised against the 29 kDa and 31 kDa protein reacted with the affinity-purified proteins in a Western blot with whole-cell extract used as antigen. The N-terminal sequence of the 29-kDa and 31-kDa proteins demonstrated the closest homologies with internal sequences from an Escherichia coli trigger factor protein (TIG.ECOLI). Out of nine other lactobacilli, the antisera reacted only with the L. reuteri and not with the other species tested.

Amino Acid Isomerases↗
PubMed1994

Identification of I-plastin, a human fimbrin isoform expressed in intestine and kidney.

The complete cDNA sequence of human intestine-specific plastin (I-plastin) was determined from a clone derived by PCR. It consists of a 97-bp 5' untranslated region, a 1,887-bp coding region, and a 1,655-bp 3' untranslated region. The coding region predicts a 629-residue polypeptide whose sequence displays 86, 75, and 73% identities with chicken intestine fimbrin, human T-plastin, and human L-plastin, respectively. Recombinant I-plastin cross-linked actin filaments into bundles in the absence but not in the presence of calcium. The I-plastin gene was mapped by PCR to human chromosome 3; the L- and T-plastin genes were previously mapped to chromosomes 13 and X, respectively. I-plastin mRNA was detected in the small intestine, colon, and kidneys; relatively lower levels of expression were detected in the lungs and stomach. In contrast, L-plastin expression was restricted to the spleen and other lymph node-containing organs, while T-plastin was expressed in a variety of organs, including muscle, brain, uterus, and esophagus. In contrast to the situation for the intestine, high levels of L- and T-plastin mRNAs were detected in Caco-2, a human colon-derived cell line. Immunofluorescence microscopy detected I-plastin in the brush border of the small intestine and colon. These results identify I-plastin as the human homolog of chicken intestine fimbrin and as a third plastin isoform in humans.

Amino Acid Sequence↗
PubMed1994

Role of EDRF/NO in parasympathetic coronary vasodilation following carotid chemoreflex activation in conscious dogs.

The role of endothelium-derived relaxing factor (EDRF) in parasympathetic coronary vasodilation following carotid chemoreflex activation induced by nicotine in conscious dogs and stimulation of the vagus nerve in anesthetized dogs was studied. Injection of nicotine (11 +/- 4 micrograms) into the carotid artery increased coronary blood flow (CBF) by 126 +/- 16% from 28 +/- 3 ml/min and reduced late diastolic coronary resistance (LDCR) by 43 +/- 4% from 3.58 +/- 0.52 mmHg.ml-1.min, accompanied by a significant increase in mean arterial pressure and a decrease in heart rate (all P < 0.01). Pacing and propranolol did not change the coronary vascular response to chemoreflex activation. There were still increases in CBF by 113 +/- 17% from 29 +/- 3 ml/min and decreases in LDCR by 41 +/- 5% from 3.13 +/- 0.52 mmHg.ml-1.min (all P < 0.01). After infusion of N omega-nitro-L-arginine (L-NNA) (30 mg/kg), the increase in CBF following chemoreflex activation was only 23 +/- 3% from 37 +/- 3 ml/min, and the fall in LDCR was 19 +/- 3% from 3.09 +/- 0.51 mmHg.ml-1.min. Stimulation of the vagus nerve showed a relationship between stimulation frequency and coronary vasodilation that was significantly inhibited by L-NNA. Thus EDRF plays an important role in mediating parasympathetic coronary vasodilation during chemoreflex activation and perhaps during many reflexes that cause vagal cholinergic vasodilation in the heart.

Acetylcholine↗
PubMed1994

Role of EDRF in the regulation of regional blood flow and vascular resistance at rest and during exercise in conscious dogs.

The contribution of endothelium-derived relaxing factor (EDRF) to the regulation of regional vascular resistance and tissue blood flow at rest and during acute moderate exercise was studied in chronically instrumented conscious dogs. Radioactive microspheres were injected before and during exercise to measure regional blood flow. An infusion of nitro-L-arginine (L-NA), an analogue of L-arginine, was used to inhibit the synthesis of EDRF and resulted in a significant increase in mean arterial pressure, associated with significantly elevated vascular resistance in heart, skeletal muscle, renal and splanchnic circulations and with decreases in tissue blood flow in those regions at rest. Acute exercise caused a typical redistribution of blood flow, in which there was vasodilation in heart and working skeletal muscles, accompanied by vasoconstriction in kidney and splanchnic circulations. L-NA resulted in significantly elevated vascular resistance during vasodilation in heart and working skeletal muscles and also significantly increased vasoconstriction in renal cortex, stomach, pancreas, liver, and colon during exercise. Blood flows during exercise were largely unaffected by L-NA treatment. Our results suggest that whereas EDRF functions to regulate basal vascular tone and vascular resistance during exercise, EDRF has a minor role in determining the pattern of the redistribution of tissue blood flow during exercise.

Acetylcholine↗
PubMed1994

Role of nitric oxide in the regulation of oxygen consumption in conscious dogs.

The role of nitric oxide (NO) in the regulation of O2 consumption was studied in chronically instrumented conscious dogs. A specific NO synthesis inhibitor, nitro-L-arginine (NLA, 30 mg/kg i.v.), significantly increased mean arterial pressure from 100 +/- 4 to 134 +/- 5 mm Hg (mean +/- SEM) and total peripheral resistance by 157 +/- 16% and reduced cardiac output by 47 +/- 3% and heart rate by 34 +/- 6% after 120 minutes. Changes in arterial blood gases were not observed. There were significant changes in PO2 (-14 +/- 2 mm Hg), O2 saturation (-21 +/- 2%), the percentage of hemoglobin as oxyhemoglobin (-21 +/- 2%), and O2 content (-3.0 +/- 0.9 vol%) and a significant increase in percent reduced hemoglobin (21 +/- 1%) in mixed venous blood, associated with an increase in O2 extraction (5.1 +/- 0.2 vol%) (all P < .01). O2 consumption was increased from 124 +/- 6 to 155 +/- 9 mL/min (P < .05). Methoxamine, titrated to have hemodynamic effects similar to those of NLA (eg, mean arterial pressure increased from 97 +/- 4 to 131 +/- 5 mm Hg), had much smaller effects on venous blood gases, hemoglobin, and O2 extraction (2.3 +/- 0.7 vol%) and no significant effect on O2 consumption. NLA also caused an increase in O2 consumption of 37 +/- 8% (P < .01) in quietly resting conscious dogs that had undergone pretreatment with hexamethonium and atropine, but no significant change in O2 consumption in dogs anesthetized with barbiturate.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Oxidoreductases↗
PubMed1994

National food contamination monitoring programmes-levels of mercury, lead and cadmium in Chinese foods.

Six hundred and thirty-four food samples of six kinds were collected from Beijing, Shanghai, Jiangsu, Sichuan, Jilin and Guangdong areas, China and Hg, Pb, Cd contents were determined. The results showed that their levels in the Chinese foods were low; their levels in meat, egg, milk and fish were generally below the national hygienic standard. The average daily dietary intake of Hg, Pb, Cd were 7.25 micrograms, 103.77 micrograms and 30.72 micrograms respectively and they were all less than the ADI established by WHO.

Adult↗
PubMed1994

[Comparative study of organ storage solutions for rat liver preservation: effects of HX and Collins I solution on sinusoidal lining cells and hepatic functions].

The liver sinusoidal lining cell injury and biochemical function changes were studied with isolated perfusion after rat livers had been preserved in HX solution or in Collins II solution. Seventy inbred Wistar rats were randomly divided into control group (n = 10), group H (preserved with HX solution, n = 30), and group C (preserved with Collins II solution, n = 30). The effects of the storage solutions were assessed by measuring the sinusoidal lining cell mortality (SLCM), Krebs-Henseleit perfusate ketone body ratio (PKBR), the hepatic sugar release (SL), and the number of livers secreting bile during isolated perfusion. The results suggest that the HX solution be much superior to Collins II solution in preventing sinusoidal lining cell injury and maintaining normal hepatic functions.

Animals↗
PubMed1994

Effects of prolonged darkness on light responsiveness and spectral sensitivity of cone horizontal cells in carp retina in vivo.

Light responses of cone- and rod-driven horizontal cells were recorded intracellularly from opened eyes of intact, immobilized carp and the effects of prolonged darkness on these cells were examined. When the retina was left in the dark, responses of cone horizontal cells to a moderate test flash presented once every 10 min gradually and steadily decreased in size (dark suppression effect). Following a repetitive presentation of the test flash, the light responsiveness of the cells was enhanced. In contrast, the rod horizontal cells did not show the dark suppression effect and the light responsiveness of these cells increased in the dark. Effects of prolonged darkness on the spectral sensitivity of L-type and R/G-type cone horizontal cells were also studied. The spectral sensitivity of L-type cells, determined just after background illumination was extinguished, agreed reasonably well with that of red-sensitive (R-) cones, but it matched better that of green-sensitive (G-) cones when determined in prolonged darkness. We further show that depolarizing responses of R/G-type cone horizontal cells to long-wavelength flashes, driven by R-cones, were abolished after prolonged darkness. Taken together, these results suggest that input from R-cones converging onto the cone horizontal cells is more significantly suppressed after prolonged dark adaptation than input from G-cones. Due to the suppression of the R-cone input, enhancement of responses of the L-type cone horizontal cells to long-wavelength stimulation in the presence of a green background light was no longer seen after prolonged darkness.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Identity elements of tRNA(Trp). Identification and evolutionary conservation.

In this study, the varying reactivities of Bacillus subtilis tryptophanyl-tRNA synthetase toward prokaryotic, eukaryotic, and halophile tRNAs were employed to define the potential identity elements on tRNA(Trp). On this basis mutagenesis was performed to obtain, through in vivo heterologous expression in Escherichia coli and in vitro transcription with T7 RNA polymerase, mutant B. subtilis tRNA(Trp) for comparison with the wild-type. These comparisons served to establish G73 and the anticodon as major identity elements, and A1-U72, G5-C68, and A9 as minor identity elements. While the tryptophanyl-tRNA synthetase from B. subtilis and E. coli require G73 to function, replacement of G73 by A73 favors the enzyme from yeast. This change points to the variation of the identity elements for the same amino acid among different organisms. The similarity in these elements between B. subtilis and E. coli tryptophanyl-tRNA synthetase, however, suggests that identity elements on tRNA, like the active centers on enzymes, undergo evolutionary change at slower rates than less essential portions of the macromolecule.

Animals↗
PubMed1993

Purification of hyperexpressed Bacillus subtilis tRNA(Trp) cloned in Escherichia coli.

To study the effects of evolutionary sequence changes on the molecular interactions of tRNA inside the cell, the Bacillus subtilis tRNA(Trp) gene has been cloned into Escherichia coli JM109 under the control of the lac promotor. Hyperexpression of the gene in minimal medium upon induction yielded 28% of total tRNA in the form of B. subtilis tRNA(Trp). The tRNA(Trp) gene product was purified by the use of a single Vydac C4 high-performance liquid chromatography (HPLC) matrix. This experimental system provided a valuable system for the hyperexpression and purification of a heterologous tRNA for studies in vitro. Moreover, because HPLC fractionation of the heterologous tRNA(Trp) gene product yielded multiple peaks, the system made possible an analysis of the molecular mechanisms for the transcriptional modifications of the tRNA(Trp) gene product in vivo.

Bacillus subtilis↗
PubMed1993

Effects of copper coordinate complexes on the scavenging of reactive oxygen species.

Effects of a 20-membered macrocyclic bicopper complex and dioxotetramine copper complexes with linear or cyclic structure on the scavenging of ROS have been studied by ESR. The results indicated that all three copper coordinate complexes have SOD mimetic activity. The dioxotetramine copper complex with linear or cyclic structure did not have the scavenging effect on .OH produced by H2O2-Fe++ and 1O2 produced by the H2O2-NaOCl system, but the 20-membered macrocyclic bicopper complex was found to be capable of depressing the intensity of the ESR spectrum of the adduct formed from TMP and 1O2 as well as making the spectrum of DMPO-OH adduct splittings. This fact may suggest that there are interactions between the ROS and 20-membered macrocyclic ring in the SOD mimic.

Cells, Cultured↗
PubMed1993

The results of treatment in 100 patients with limited-stage small cell lung cancer.

BACKGROUND: In an attempt to improve treatment results of small cell lung cancer (SCLC), combined induction chemotherapy and thoracic and prophylactic brain radiation therapy were administered. METHOD: From December 1980 to December 1987, 112 patients with limited-stage SCLC were treated with combination induction chemotherapy and thoracic or prophylactic brain radiation therapy; 100 were evaluable. RESULTS: The complete response rate was 40%, and complete and partial responses totaled 94%, with a 5-year survival rate of 23%. There was no difference in remission and survival rates between three-drug and four-drug induction chemotherapeutic regimens. Six chemotherapeutic courses produced longer survival than less therapy. Although the occurrence of brain metastases was no different with or without prophylactic brain radiation therapy, the 3-year survival after this procedure was improved. CONCLUSION: Treatment of limited-stage SCLC with induction chemotherapy and thoracic and prophylactic brain radiation therapy produced improved remission and survival rates.

Adult↗
PubMed1993

Vaccination of bovines against Schistosomiasis japonica with cryopreserved-irradiated and freeze-thaw schistosomula.

Four laboratory tests and one field trial with cryopreserved irradiated (CI) schistosomula vaccine and a freeze-thaw (F/T) vaccine against bovine Schistosomiasis japonica were carried out in 1979 and 1980 with the following results: (1) Single intradermal vaccination in buffalo calves each with 10,000 20 krad CI Schistosomula plus 1 ml BCG gave 62% worm reduction (P < 0.05). Using the same protocol 55% worm reduction (P < 0.01) was obtained in cattle. (2) Buffalo calves immunized twice, at a 1.5 month interval, with 10,000 and 20,000 CI schistosomula, respectively, resulted in a worm reduction 65%. (3) In a preliminary field trial with 10,000 CI schistosomula plus 1 ml BCG resulted in a worm reduction of 53% in buffalo calves. (4) Intradermal vaccination of 30,000 F/T schistosomula with 1 ml BCG was also tried in cattle and revealed a worm reduction of 57% but increasing the number of vaccinations did not improve the protective effect. (5) Evidence regarding the effects of immunization with CI vaccine in buffaloes and F/T vaccine in cattle, on the number of eggs and miracidia and that of female worms themselves was obtained. (6) Immune responses, cellular and humoral, elicited in buffaloes vaccinated with CI schistosomula were detected by means of Lymphocyte Transformation Assay and Enzyme Linked Immunosorbent Assay.

Animals↗