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Biomedical subjects

T Wang

Publications and source records attributed to T Wang.

At least 361 records · Page 20Linked to original sources
PubMed1999

[Determination of three flavonoids and ferulic acid in Pleurospermum hookeri C. B. Clarke var. thomsonii C. B. Clarke by HPLC].

OBJECTIVE: To establish a reversed phase HPLC method for separation and determination of licochalcone A, ferulic acid, isoliquiritigenin and nobiletin in Pleurospermum hookeri var. thomsonii. METHOD: Using ODS column with methanol-water(containing 1% acetic acid)(73:27, 28:72, 59:41) and methanol-water(65:35) as the mobile phase, the flow rate was 1 ml/min, the column temperature was 35 degrees C and UV detection at 345, 320, 345, 332 nm, different extraction methods for the sample were compared. RESULT: The average recoveries were 99.45%, 98.13%, 97.81% and 96.58%, the relative standard deviations were 0.83%, 0.99%, 0.73% and 1.55%, and the contents were 0.728, 0.124, 0.0830 and 0.0237 mg/g. CONCLUSION: This study provides a scientific basis for quality evaluation, quality control and resources development and utilization of P. hookeri var. thomsonii.

Apiaceae↗
PubMed1999

[Expression of xylose-metabolic key genes of Trichoderma reesei on various carbon sources measured by a series of Northern hybridizations].

The expression of xylose reductase (XR), xylitol dehydrogenase (XDH) and transaldolase (TAL) genes from Trichoderma reesei, measured by Northern hybridization, were studied by adding different carbon sources (20 kinds, including single and mixed carbon sources) separately into the basal medium on which T. reesei QM9414 was grown. The experiment results indicated that the two disaccharides: sophrose and xylibiose act as a strong inducer for the expression of xr and xdh. The lactose and arabinose were identified as inducer also. The presence of glucose repressed the transcription of xr and xdh. When glucose depleted. xr and xdh were expressed at certain level, implying that expression of xr and xdh are controlled by the carbon catabolite repression mechanism and there existed a constitutive base level's expression of xr and xdh when the catabolite repression mechanism was derepressed. On the other hand, transaldolase gene strongly expressed on all the carbon sources used.

Aldehyde Reductase↗
PubMed1999

[Field application of oral artesunate for preventing Schistosoma japonicum infection].

AIM: To assess the preventive effect of oral artesunate against S. japonicum infection. METHODS: Residents in two pilots in the schistosomiasis endemic regions, 562 cases in Yanghe pilot, Wangjiang County and 218 cases in Shashan pilot, Guichi City, Anhui Province, were selected for this study. The residents were divided into two groups. Group I received artesunate 6 mg/kg once every 2 weeks for 4 times 2 wk after contacting with infested water from July to September in 1997. Group II received the same dosage of placebo at the corresponding times. Four weeks after the last administration, stool examination using hatching method and Kato's method was conducted to evaluate the effect. RESULTS: In Yanghe pilot, 2 cases were hatching positive in the artesunate-treated group with an infection rate of 0.7% (2/273), while 11 cases were stool positive in placebo group with an infection rate of 3.8% (11/289) and a mean EPG of 26.40 +/- 1.49. In Shashan pilot, all cases in artesunate-treated group were stool negative, while 7 cases were stool positive in the placebo group with an infection rate of 6.3% (7/111), and a mean EPG of 14.23 +/- 2.14. The protection rate of artesunate was 80.9% and 100%, respectively, in the two pilots. CONCLUSION: Artesunate can protect the residents from S. japonicum infection effectively.

Administration, Oral↗
PubMed1999

[Expression and clinical implication of multidrug resistant-associated protein gene (MRP) in patients with laryngeal squamous cell carcinoma].

OBJECTIVE: To study the relationship between the expression of MRP mRNA and the clinical pathological characteristics of the patients with laryngeal squamous cell carcinoma. METHOD: Reverse transcription polymerase chain reaction (RT-PCR) assay was used to detect the expression of MRP mRAN in 35 patients. RESULT: The positive expression rate of MRP mRAN was 45.7 percent (16/35) in laryngeal carcinoma. It was higher in advanced (T3-4) patients than that in early (T1-2) cases (P < 0.05) and showed a significant correlation with metastases of cervical lymph node (P < 0.01). CONCLUSION: It is suggested that the expression of MRP mRNA may not only play an important role in multidrug resistance of laryngeal carcinoma, but also influence their biological behavior of dissemination and metastases.

Adult↗
PubMed1999

[Orthogonal experiments on extract-concentrate-spray drier related technological factors for shuguanwenjing granule].

By using orthogonal tests, with the ratio of dry powder abtained from crude drugs and the Icariin content of powder as criteria, the correlation among the extract-concentrate-spray drier technology for Shuguanwenjing Granule and the main technological factors such as time and frequency of decoction, volume of water, relative density of extract, the in-temperature and out-temperature of spray drier, etc. was studied.

Drug Combinations↗
PubMed1999

[Preservation of laryngeal function in surgical treatment of hypopharyngeal carcinoma].

OBJECTIVE: To study of the feasibility, the surgical techniques and the results of laryngeal function preservation in surgical treatment of hypopharyngeal carcinoma. METHODS: A retrospective review of 305 (279 males, 26 females, ages ranging from 14 to 77 years) cases with malignant neoplasms of the hypopharynx that were treated from 1978 to 1996 were accomplished. Of the 305 (stage I, 6; II, 12; III, 82; IV, 205) cases, 234 were originated from pyriform sinus, 21 from postcricoid, 35 from posterior pharyngeal wall and 15 from superior hypopharynx. Two hundred and eighty-five patients received 55-75 Gy postoperative radiotherapy. RESULTS: The overall 5 year survival rate of 305 patients was 44.8%; for stage I, the survival rate was 83%; stage II, 71%; stage III, 58% and stage IV, 36.5%. Of the 305 patients, 206 cases (67.54%, stage I, 6; II, 12; III, 65; IV, 123) were surgically treated with laryngeal functions preserved and 99 (32.46%, stage III, 17; IV, 82) total laryngectomy. There were no significant differences in 5-year survival between the functionally preserved group and none functional group. Among the 206 functional preserved patients, 139(67.5%) had all functions preserved (voice, respiration and deglutition) and 67(32.5%) partially preserved (voice and deglutition). CONCLUSION: Only a few patients (31/305, 10%) of hypopharyngeal carcinomas require total laryngectomy, and the preservation of the normal part of the larynx is feasible for the eradication of tumor and preservation of laryngeal function.

Adolescent↗
PubMed1999

[Surgical treatment of laryngotracheal stenosis].

OBJECTIVE: To evaluate the surgical treatment results of laryngotracheal stenosis. METHODS: Forty-five patients with laryngotracheal stenosis, atresia or defects who had been treated surgically were reviewed. Different operative reconstructions were used accordingly, such as simple scar resectoin and dilatation, mucosa resuturing, Z-plasty, flap reconstruction, sleeve resection. RESULTS: Forty-three patients had been treated successfully with good airway patency, although 37 of them had hoarseness of voice. One patient lost to follow-up and another had compromised airway after operation. CONCLUSION: The different methods of surgical reconstruction used here for the laryngotracheal stenosis proved to be effective.

Follow-Up Studies↗
PubMed1999

[Expression and clinical implication of multidrug resistance gene and multidrug resistant-associated protein gene in patients with hypopharyngeal squamous cell carcinoma].

OBJECTIVE: To study the relationship between the expression of MDR-1 mRNA/P-glycoprotein (P-gp). MRP mRNA and the clinical pathological characteristics of the patients with hypopharyngeal squamous cell carcinoma. METHODS: Reverse transcription polymerase chain reaction(RT-PCR) assay was used to detect the expression of MDR-1 mRNA and MRP mRNA in 25 specimens of the untreated advanced hypopharyngeal carcinoma. Meantime, immunohistochemistry SABC technique was used to test P-gp in 60 tumor specimens. RESULTS: The positive expression rates of MDR-1mRNA and P-gp in hypopharyngeal carcinoma were 48 percent (12/25) and 38.3 percent(23/60), respectively. There was a correlation between expression of MDR-1 mRNA and its product P-gp in 25 patients using RT-PCR assay(P < 0.05). The positive expression rate of MRP mRNA was 52 percent (13/25), which was significantly related to metastases of cervical lymph node (P < 0.01). CONCLUSION: Forty-eight percent of the untreated patients with hypopharyngeal carcinoma presented positive expression of MDR-1 mRNA, which was correlated with its gene product P-gp. The expression of MRP mRNA was associated with increased tumor dissemination and metastases.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

[Continuous positive airway pressure therapy after uvulopalatopharygoplasty].

OBJECTIVE: To investigate if uvulopalatopharygopalasty (UPPP) compromised continuous positive airway pressure (CPAP) therapy. METHODS: Automated continuous positive airway pressure(Auto CPAP) was applied to treat 15 patients with obstructive sleep apnea syndrome(OSAS) whose apnoea-hypopnoea index (AHI) was still higher than 20 after UPPP, and also it was used in the treatment of 32 randomly selected OSAS patients who had not had any treatment before. The treatment results of these 2 groups were compared. RESULTS: It was found that AHI and apnoea index(AI) between the 2 groups after Auto CPAP treatment were not significantly different (P > 0.05), however, lowest SO2(LSO2) after Auto CPAP treatment of the UPPP group was higher than that of the other group (P < 0.01). The AHI, AI and LSO2 in each group were significantly different before and after Auto CPAP treatment (P < 0.01 in both cases). CONCLUSION: It is suggested that CPAP remains effective after UPPP and UPPP doesn't compromise CPAP therapy.

Adult↗
PubMed1999

[Study on spectral emission characteristics of infrared lamps].

The spectral characteristics at wavelength ranges of 0.35-0.85 microm and 1.72-16.7 microm (5800-600 cm(-1)) for both domestic and imported infrared lamps used in scientific research, industry, medical service, home electrical appliance etc. have heen studied and compared. This paper has provided the theoreical and experimental bases for their applications and improvement in designs, technology of manufacture, quality and performance.

English Abstract↗
PubMed1998

Intracerebroventricular (i.c.v.) administration of mouse leptin in rats: behavioral specificity and effects on meal patterns.

Leptin is a protein that is produced primarily in fat tissue and is thought to be a lipostatic feedback signal for the regulation of body fat stores. The purpose of this study was to determine the behavioral specificity of i.c.v.-administered mouse leptin in rats and to assess the effects on meal patterns. Using a modified two-bottle paradigm we examined the putative aversive response to i.c.v. doses of 1, 5, 7, 10, and 30 microg of mouse leptin. Artificial CSF and intraperitoneal lithium chloride served as negative and positive controls, respectively. Saccharin consumption in all leptin treatments was not significantly different from the negative control. Following a recovery period, rats from the same group were used to assess the effects of a 30-microg i.c.v. dose on cumulative food intake and meal patterns using a computer-based system for acquisition of feeding data. Leptin (i.c.v.) significantly increased intermeal interval and decreased meal size. We, therefore, conclude that mouse leptin, at doses up to 30 microg i.c.v., is not aversive in the rat, and that leptin has a multiphasic effect on meal patterns.

Animals↗
PubMed1998

Responses of lean and obese Zucker rats to centrally administered leptin.

Obese (Lepr(fa)/Lepr(fa)) Zucker rats have a missense mutation in the leptin receptor gene. One amino acid substitution in the extracellular domain common to all known leptin receptor proteins results from this mutation. Obese Zucker rats are unable to respond behaviorally to leptin which is peripherally administered. However, conflicting reports exist on whether obese Zucker rats can respond to centrally administered leptin. The purpose of this study was to determine whether obese Zucker rats responded behaviorally and metabolically to intracerebroventricularly (i.c.v.) administered leptin and to compare the responses of lean and obese Zucker rats. We found that both lean and obese Zucker rats had similar body weight and food intake responses when administered a single i.c.v. leptin injection in a range of doses (1.25, 2.5, 5, and 10 microg), as well as daily i.c.v. administered leptin for five consecutive days. Both single and daily leptin administration also decreased respiratory quotient (RQ) similarly in lean and obese Zucker rats, indicating mobilization of fat as an energy source for leptin-treated rats. After withdrawal of daily leptin treatment, lean and obese Zucker rats exhibited different recovery responses. It is concluded that obese Zucker rats can respond to exogenous leptin when leptin is delivered into the brain ventricles.

Animals↗
PubMed1998

[Comparison of genotype and intellectual phenotype in untreated phenylketonuric children].

OBJECTIVE: The main feature of phenylketonuria(PKU) is mental retardation. Although classical PKU is defined as that the hepatic phenylalanine hydroxylase (PAH) activity ranges 0-1% of normal enzyme, the untreated PKU patients show a wide range of intellectual phenotype. This study sought to find the molecular basis of such variation of intellectual phenotype among PKU. METHODS: 45 classical PKU patients included in the research were screened for detecting six mutant alleles which were rather common among Chinese PKU patients, i.e. R243Q, R413P, Y204C, Y356X, W326X and R111X. PCR-ASO and PCR-SSCP techniques were used. The expression of those mutant PAH genes was analysed by methods of site-directed mutagencies. 27 PKU patients whose two mutant alleles were both defined were involved in this study. The IQ of these patients were tested by DDST system. RESULTS: Among 27 patients, 4/27 (15%) were mild retardation, 10/27(37%) were moderate, the severe mental retardation accounted for 12/27(44%). The relationship between genotype and intellectual phenotype in this group was examined. It was found that the intellectual phenotype of 8 patients were compatible with genotype but not well matched in 19 cases. The enzyme activity of Y204C expressed in vitro was 100%, but all 3 patients with Y204C/Y204C were severely mental retarded. Enzyme activities of R413P and Y356X were <3% and 0 respectively in expression analysis, but the patients in this group had mild or moderate mental retardation. CONCLUSION: Intellectual phenotype was not well matched with the genotype in classical PKU patients, so that genotype can not be used to predicte the intellectual phenotype in PKU patients.

Child↗
PubMed1998

Peptide containing the BCR oligomerization domain (AA 1-160) reverses the transformed phenotype of p210bcr-abl positive 32D myeloid leukemia cells.

We first showed that the introduction of a bcr-abl transcription unit into the 32D murine myeloid cell line (P210bcrabl32D) converts this cell line from an IL3 dependent cell line to an IL3 growth independent cell line. We next cloned a fragment of the bcr-abl cDNA, which codes for the bcr oligomerization domain and neighboring regions. To test for a transformation inhibitory effect of this oligomerization inhibitory peptide transcription unit on the p210bcr-abl mediated IL3 independent growth of the P210bcrabl32D cell line, we transiently co-electroporated into the growth factor dependent 32D cells, mixtures of plasmids which contained varying ratios of the plasmid expression vectors for the bcr oligomerization inhibitory peptide along with a smaller amount of the plasmid expression vector for the full length p210bcr-abl. (The P210bcr-abl protein converts the 32D from a growth factor dependent into a growth factor independent cell line.) We then showed that the oligomerization domain containing fragment from the bcr and bcr-abl proteins, can be used to inhibit the IL3 independent growth of p210bcr-abl positive 32D cells. These studies may be of eventual interest for those investigators whose goal is to design molecular therapeutic approaches to CML based on the use of peptidomimetic chemical functionalities, which mimic the structure and the inhibitory binding properties of the oligomerization domain containing fragment so as to inhibit the transforming function of the P210bcr-abl oncoprotein.

Animals↗
PubMed1998

Reversal of scopolamine-induced deficits in radial maze performance by (-)-huperzine A: comparison with E2020 and tacrine.

The effects of (-)-huperzine A ((5R,9R,11E)-5-amino-11-ethylidene-5,6,9,10-tetrahydro-7-methyl-5, 9-methanocycloocta[b]pyridin-2(1H)-one), and of the hydrochloride salt of E2020 ((R,S)-1-benzyl-4-[(5,6-dimethoxy-1-indanon)-2-yl]-methyl piperidine) and tacrine (9-amino-1,2,3,4-tetrahydroacridine), on the scopolamine-induced memory deficits in rats were compared in a radial maze, using a 4-out-of-8 baiting procedure. Scopolamine (0.15 mg/kg, i.p.) caused significant impairment in the rats' ability to fulfil the radial maze task. (-)-Huperzine A (0.2-0.4 mg/kg, p.o.; 0.1-0.4 mg/kg, i.p.) had greater efficacy than E2020 (0.6-0.9 mg/kg, p.o.; 0.3-0.6 mg/kg, i.p.) and tacrine (1.5-2.5 mg/kg, p.o.; 0.3-0.6 mg/kg, i.p.) on the improvement of scopolamine-induced working and reference memory errors, respectively. There appeared to be an inverse bell-shape dose-dependent effect for all three compounds tested. The compared data demonstrate that (-)-huperzine A is the most potent and orally active acetylcholinesterase inhibitor of the three, and fits more closely the established criterions for an ideal acetylcholinesterase inhibitor to be used in clinical studies.

Alkaloids↗
PubMed1998

Ion-exchange column chromatographic method for assaying purine metabolic pathway enzymes.

High energy phosphate levels fall rapidly during cardiac ischemia and recover slowly (more than one week) during reperfusion. The slow recovery of ATP may reflect a lack of purine metabolic precursors and/or increased activity of purine catabolic enzymes such as 5'-nucleotidase (5'-NT, EC 3.1.3.5) and adenosine deaminase (ADA, EC 3.5.4.4). The activity of enzymes involved in both the catabolism of ATP precursors (5-NT and ADA) and the restoration of ATP from slow synthetic pathways [adenosine kinase (AK, EC 2.7.1.20), adenine phosphoribosyl transferase (APRT, EC 2.4.2.7) and hypoxanthine phosphoribosyl transferase (HPRT, EC 2.4.2.8)] may directly affect the rate of ATP recovery. Strategies to enhance recovery will depend on the relative activity of these enzymes following ischemia. Their activity in different species and their response to ischemia are not well characterized. Hence, rapid assay methods for these enzymes would facilitate detailed time course studies of their activities in postischemic myocardium. We modified a single ion-exchange column chromatographic method using DEAE-Sephadex to determine the products of incubation of 5'-NT, AK, APRT and HPRT with their respective substrates. The uniformity of the final product measurement procedure for all assays permits the activities of the four enzymes to be rapidly determined in a single tissue sample and facilitates the study of a large number of samples. This technique should also be useful for enzymes of the pyrimidine metabolic pathway.

5'-Nucleotidase↗