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Biomedical subjects

H Yu

Publications and source records attributed to H Yu.

At least 163 records · Page 9Linked to original sources
PubMed2001

Mechanosensitive channel currents recorded in rat microvascular endothelial cells with whole-cell mode.

Using the whole-cell patch-clamp technique, we recorded delayed outward currents in rat brain microvascular endothelial cells (BRMECs), which were nearly completely inhibited by 20 mmol/L extracellular TEA-Cl and 5 mM extracellular CsCl. Whole-cell currents were elicited under voltage clamp condition by 2100 ms depolarizing voltage pulses applied every 7 s between -100 to 90 mV in 10 mV increment from a holding potential of -100 mV. The currents were defined as delayed rectified K+ currents (IKv), which were inhibited in a concentration-dependent manner by bath application of TEA-Cl, with an IC50 approximately 2.0 mM, similar to that reported on IKv in other preparations. In the present of mechanical force, outward currents were increased in amplitude as compared with controls. These mechanical force induced currents were also defined as IKv, which are different from previous described mechanosensitive currents with characteristic of inward rectifier.

Animals↗
PubMed2001

[A comparative study on the sensitivity and specificity of cholinesterase and glutathione s-transferase in Gammarus pulex L].

Studies on the influences of lindane, pirimiphos methyl, permethrin, zinc and dodecyl linear alkybenzene sulfonate (LAS) on the activity and toxicity of cholinesterase (ChE) and glutathione s-transferase (GST) in Gammarus pulex L. showed that only pirimiphos methyl caused a change in ChE activity in Gammarus, with a significant reduction in enzyme activity after 24 h and 48 h exposure. Both lindane and permethrin caused a change in GST activity in Gammarus, with a significant increase in enzyme activity after 48 h exposure. Lindane alos caused a significant increase in GST activity after 24 h exposure. Biomarkers ChE and GST were demonstrated a high degree of specificity and sensitivity in comparison to the lethality assay, but GST activity was less specific than ChE activity.

Animals↗
PubMed2001

[Identification of key toxicants in a bleaching effluent--a case study].

The toxicity identification evaluation (TIE) was conducted with a toxic bleaching effluent to identify its toxic components. Toxicity characterisation procedures (phase I) indicated that the primary toxicants in the effluent were volatile, and could be reduced by sodium thiosulfate. Toxicity-based fractionation techniques (phase II) were conducted, and the oxidation organic chloridates were found not to be the major toxicants. Deletion approach of phase III confirmed that the toxicity decreased with the decrease of free and total residual chlorine concentrations, indicating that Cl2, HClO and ClO- were identified as primary toxicants in the effluent.

Chlorine↗
PubMed2001

[Study on sexual and drug use behaviors of high risk among sex workers in entertainment in establishments in Shanghai].

OBJECTIVE: To understand the types of entertainment establishments involved in commercial sex and Acquired immunodeficiency syndrome (AIDS) related risk behaviors among sex workers. METHODS: One district in Shanghai was selected. All entertainment establishments in the district were mapped. In-depth interview was carried out to collect information about demographic, sexual, drug use, measures of self-protection, condom use, history with sexually transmitted disease (STD) and health care seeking behaviors. RESULTS: Sixty-three sex workers were recruited from 38 places, of which, 38 from beauty parlors, 13 from pubs/bars and sauna settings, 10 from KTV and 2 freelance. The average age was 25 (17-45) years old. 73% were not permanent residents. Thirty-seven had reportedly engaged in commercial sex activities. Some reportedly had sex even during menstruation and involved in-group sex. Five drug users and 3 of them reported injecting and sharing needles. Ten of them knew that other sex workers had used drugs. Sixteen (25%) reportedly using condoms but only 4 for disease prevention. Another 2 reported consistent condom use with clients but never used with boyfriends or steady partners. Twenty-two (35%) reported suffering from STDs at least once. Twenty-six (41%) reported seeking care when having diseases, with 38% going to public clinics, 27% to pharmacy and 35% to private clinics. CONCLUSION: AIDS related sexual and drug injecting high-risk behaviors were common among sex workers in Shanghai. Specific and effective interventions, particularly the implementation of 100% condom use program at all entertainment establishments are called with much urgency.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Activity identification of anti-caspase-3 mRNA hammerhead ribozyme in both cell-free condition and BRL-3A cells.

OBJECTIVE: To study the transcription effects and cleavage activities of rat caspase-3 specific hammerhead ribozyme (Rz107) in both cell-free conditions and BRL-3A cells. METHODS: Rat caspase-3 gene fragment was cloned into the pGEM-T EASY vector under the T7 promoter control. The 32P-labeled caspase-3 transcript was the target-RNA. Rz107 genes designed against caspase-3 mRNA were cloned into vector p1.5 between 5'-cis-Rz and 3'-cis-Rz. 32P-labeled ribozyme transcripts were incubated with target-RNAs at different conditions and autoradiographed after denaturing gel-electrophoresis. Rz107 was electroporated into BRL-3A cells and the Rz107 expression was analyzed by RT-PCR. RESULTS: In cell-free conditions, Rz107 was active at 37 degrees C. The optimal temperature was 50 degrees C. The Km and Kcat were 14.13 nmol/L and 2.31.min-1 respectively. Intracellular cleavage efficiency of Rz107 was 37%, as analyzed by RT-PCR. This indicated that the design of Rz107 was correct, and Rz107 had the activity of common enzymes. CONCLUSIONS: Rz107 in cell-free conditions possessed perfect specific catalytic cleavage activity, and it can also cleave the target RNA successfully in cells. The results illustrate the feasibility of ribozyme therapy as a potential alternative approach for treating liver disease caused by apoptosis.

Animals↗
PubMed2001

Hepatitis B virus S gene mutants in infants infected despite immunoprophylaxis.

OBJECTIVE: To assess the correlation between hepatitis B virus (HBV) surface gene mutant infection and hepatitis B (HB) vaccination failure. METHODS: Using sera from 106 infants who were born to HBV carrier mothers and failed in HB immunoprophylaxis, HBV S gene was amplified by PCR, transferred to nylon membranes for Southern blots, and then hybridized with oligonucleotide probes. Eleven of non-hybridizing samples were used for DNA sequencing. RESULTS: 93.4% (99/106) of the samples were HBV DNA positive, and 30.3% (30/99) failed to hybridize with at least one of the four probes. DNA sequencing confirmed that 10 of the 11 samples had an S gene mutation with amino acid (aa) change. The identified mutants included nucleotide (nt) 546T-->A (aa131N-->T), nt531T-->C (aa1261-->T), nt491A-->C (aa113T-->P), nt491T-->A (aa113S-->T), nt533C-->A (aa127P-->T), nt581T-->A (aa143S-->T), nt636A-->T (aa161Y-->F), and nt679A-->C (aa175L-->F). The sequence in one mother-infant pair was completely the same, with mutations at aa131 and aa161. CONCLUSIONS: The prevalence of HBV surface mutants is about 30% in the children failing in HB vaccination. HBV mutants can infect infants by maternal-infant transmission.

DNA, Viral↗
PubMed2001

[Bronchioloalveolar carcinoma: a retrospective analysis of 52 patients].

OBJECTIVE: To present the treatment and prognosis of bronchioloalveolar carcinoma (BAC). METHODS: A retrospective study was conducted on 52 bronchioloalveolar carcinoma patients admitted from April 1990 to April 2000 with emphasis on clinical manifestations, treatment and survival. All lesions were pathologically proved as either localized or diffused type. RESULTS: These 52 cases comprised 2.5% lung tumors treated in the same period. Its clinical symptoms were similar to those of the other lung cancers. Short of breath and positive physical chest findings were more common in the diffused type. Forty-seven of these 52 patients underwent surgery and 5, chemotherapy. Follow-up showed that 28 (53.8%) patients have died; 10 (19.2%) of recurrence and 18 (34.6%) of metastasis with a median survival of 24.3 months for the localized type and 5.3 months for the diffused type (P < 0.05), The median survival of stage II BAC was 26.8 months in contrast of 42.5 months of stage II non-BAC adenocarcinoma group(P < 0.05). However, there was no significant difference in the overall survival rates of BAC and non-BAC squamous carcinoma (P > 0.05). Even though, trend analysis still showed that there is a tendency of decline in the survival rates from squamous cancer, non-BAC and BAC though (P < 0.05). CONCLUSION: Localized BAC gives a better prognosis than diffused BAC of which the biological characteristics are different from those of the non-BAC. Compared with the non-BAC, a more active postoperative treatment should be considered for the BAC patients, such as postoperative chemotherapy and or radiotherapy, especially for stage II BAC lesions.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2001

[The clinical features and prognostic factors of 22 patients with primary central nervous system lymphoma].

OBJECTIVE: The authors present a retrospective analysis of 22 patients with primary central nervous system lymphoma(PCNSL) in order to provide a reasonable basis for the diagnosis and treatment of the disease. METHODS: This report involves a clinicopathological study of 22 patients with histologically proven PCNSL, all diagnosed between January 1993 and May 2000. Univariate and multivariate regression analysis are used to determine prognostic factors significantly associated with an unfavorable or favorable impact on survival. RESULTS: The cohort included 11 men and 11 women whose median age at diagnosis was 49.5 years. At the end point of follow-up, 11 died. The median survival time for the patients in study was 14.5 months. With univariate and multivariate regression analysis, prognostic factors significantly associated with survival included intrathecal injection(P = 0.005) and local/diffuse neurological deficit (P = 0.031). CONCLUSION: There continues to be a significantly increasing incidence of PCNSL. This survey throws light on the clinical and prognostic features of this uncommon disease. Through univariate and multivariate regression analysis the authors highly recommend a therapeutic regime including surgery, intrathecal injection and chemotherapy, especially those drugs capable of passing blood-brain barrier, for example high dose MTX.

Adolescent↗
PubMed2001

[Effect of Rheum palmatum decoction on increasing intelligence].

OBJECTIVE: To observe the nootropic effect of Rheum palmatum decoction in mice. METHOD: Step-down test. RESULTS: Rheum palmatum decoction could increase learning and memory ability of old mice and also improve the impairments of memory acquisition, memory consolidation and memory retrieval induced by scopalamine, NaNO2 and 40% EtOH respectively in mice. CONCLUSION: Rheum palmatum decoction contains the substances of increasing intelligence which may be substantial basis of the decoctions mainly containing Rheum palmatum theraping aphasia from apoplexy, senile dysmnesis, sequel from brain trauma, etc.

Animals↗
PubMed2001

[Analysis of the nucleotide sequence for C and NS5 regions and the genotype of HCV isolate in Shandong Province].

OBJECTIVE: To study the genotype of HCV epidemic strains in Shandong Province. METHODS: HCV fragments of C(432 bp) and NS5(319 bp) regions were amplified by RT nested PCR. The fragments were cloned to T vector and sequenced by dideoxynucleotide chain termination reaction. RESULTS: Three of all 4 strains in C region were 1b genotype, and 1 was 2a. All of 10 strains of NS5 region were 1b genotype. No other genotype was found in this region. The homology of nucleotide sequence was over 90% compared with that of more than 50 strains in Gen Bank. CONCLUSIONS: The major genotype of HCV epidemic strains in Shandong Province is 1b. The 2a genotype is also found in this area.

Genotype↗
PubMed2001

[Shear bond strengths of four types of adhesive resin agents to GI II glass infiltrated ceramic].

OBJECTIVE: The shear bond strength of four adhesive resins bonded to GI II glass infiltrated alumina ceramic was investigated in this experiment. METHODS: A total of 40 ceramic blocks and 40 tooth blocks were prepared and divided into 4 experimental groups, including group A (CereDual and silicoating), group B (Calibra and silicoating), group C (Panavia) and group D (Super C&B and silicoating). The shear strength of four different bonding systems to dentin was tested respectively. The data were statistically analyzed. RESULTS: More than 13 MPa of bonding strength was achieved using the traditional Bis GMA bonding resin (groups A and B), and more than 16 MPa was obtained using the improved Bis GMA bonding resin (group C and D). There was statistical difference between groups A, B and group C, D. CONCLUSION: It can be implied that an ideal bonding can be obtained by using different bonding materials and processing the dentin surface with the suitable conditioner.

Dental Bonding↗
PubMed2001

[Shear strength of bond of the dentin to GI-II glass-infiltrated alumia ceramic agter varying modes of surface conditioning].

OBJECTIVE: The adequate surface conditioning method for GI-II glass infiltrated alumia ceramic was investigated. METHODS: The test specimens were divided into 3 groups (A. HF + silicon, B. sandblasting + silicone and C. thermal silicoating + silicone). Shear bonding strengths of porcelain bonded to dentin were tested. RESULTS: The bond strength of group A and B slightly increased after one day but decreased sharply after 30 days. However, no statistical significance was observed. The group C showed a pronounced enlargement of bond strength after one day and had a durable bond after 30 days' thermal cycling. It is statistically significant when group C was compared with group A and B. CONCLUSION: It can be inferred that silicoating method be a better way for glass infiltrated alumia ceramic bonding.

Aluminum Oxide↗
PubMed2001

[Determination of alkali metals, ammonium ion and alkyl amines by non-suppressed ion chromatography].

The determination of Li+, Na+, NH4+, K+, CH3NH2, CH3CH2NH2 and CH3CH2CH2NH2 by non-suppressed ion chromatography using sulfamic acid as mobile phase is described. A cation-exchange column was employed for separation with conductivity detection. The effect of the eluent concentration on retention value was studied. The retention value of ions decreased with increasing the eluent concentration. The suitable eluent concentration was 4.0 mmol/L. When 4.0 mmol/L sulfamic acid was used as mobile phase, the detection limits (mg/L) for Li+, Na+, NH4+, K+, CH3NH2, CH3CH2NH2 and CH3CH2CH2NH2 were 0.008, 0.029, 0.027, 0.099, 0.069, 0.163 and 0.417 and the linear ranges of calibration curve(mg/L) were 0.008-20, 0.029-20, 0.027-20, 0.099-30, 0.069-30, 0.163-40 and 0.417-40, respectively. The method has been applied to the determination of tap water samples. The recoveries of added standard were 94.0%-97.6%.

Amines↗
PubMed2001

[Introduction of Vitreoscilla hemoglobin gene in a recombinant E. coli for PHB production].

Vitreoscilla hemoglobin gene (vgb) was introduced into the recombinant Escherichia coli VG1(pTU14) for production of poly-beta-hydroxybutyrate (PHB), in order to enhance the oxygen uptake of strain from molecular level and to solve the problem of oxygen limitation in process of fermentation. The carbon monoxide difference spectra analysis of Vitreoscilla hemoglobin (VHb) showed that vgb could be successfully expressed in VG1 (pTU14), and this expression was under the regulation of dissolved oxygen (DO). The higher amounts of VHb could be got correspond to the lower level of DO. Because of the introduction of vgb, cell growth and PHB accumulation of VG1 (pTU14) were all strongly promoted during the process of batch culture.

Bacterial Proteins↗
PubMed2001

[Application of differential wavelet in detecting QRS complexes of ECG signal].

An algorithm based on wavelet transforms (WT'S) has been developed for detecting QRS complexes of ECG signal. In this paper, we use Mallat algorithm to calculate dyadic Marr wavelet transforms, analyse the relationship between singularity of the signal (the peak of R wave) and local maximal value of WT's from the view of equivalent wavelet filter, discuss the performance distinction between quadratic differential wavelet and single differential wavelet for singularity detection. Some other tactics are also applied to improve the anti-interference performance of the algorithm and to increase the correct detection rate of QRS complexes. Verified by the MIT-BIH Arrhythmia Database, the correct detection rate of QRS complexes is 99.8%.

Algorithms↗
PubMed2001

[Analysis of essential oil from Artemisia annul L. by extraction of different methods].

Essential oils from Artemisia annul L. were extracted with CO2 supercritical fluid and steam distilation. The essential oils were analyzed and contrasted by GC-MS. 114 components were identified by computer index. The rate of total components by supercritical CO2 fluid extraction and steam distillation were 81.24% and 85.75% respectively. Some of them such as diphenylene-Methane, Phenyl-1-naphthylamine were discovered from the plant for the first time.

1-Naphthylamine↗