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Biomedical subjects

H Yu

Publications and source records attributed to H Yu.

At least 109 records · Page 6Linked to original sources
PubMed2001

Contributions of biofilm versus suspended bacteria in an aerobic circulating-bed biofilm reactor.

This study demonstrated that, during the two-step biodegradation of toluene in an aerobic circulating-bed biofilm reactor, biofilm and suspended bacteria played critical roles. Although the suspended bacteria were less than 1% of the total amount of biomass in the system, they transformed up to 30% of the toluene into its intermediate in the bulk liquid phase. On the other hand, most of the toluene intermediate was removed inside the biofilm, where diffusion resistance reduced the toluene concentration, thereby relieving inhibition to the degradation reaction of the intermediate. The suspended bacteria are most important for rapidly biodegraded substrates, for which diffusion limitation controls the kinetics in the biofilm. They lose importance when the effects of an inhibiting substrate must be overcome.

Bacteria, Aerobic↗
PubMed2001

The effect of fluid shear stress on ICAM-1 expression of rat brain microvascular endothelial cells.

Intercellular adhesion molecule-1 (ICAM-1) is an adherence molecule that is an important factor in many pathophysiological processes such as atherosclerosis, thrombosis and inflammation. It is secretion of endothelial cells by a variety of biochemical stimulations. But hemodynamic forces can also induce various functional changes in vascular endothelium. Some researches have proved that shear stress can modulate the expression of ICAM-1. But most of them examine the regulation of expression of ICAM-1 in human umbilical vein endothelial cells. There is no detail on the effect of shear stress (SS) on ICAM-1 expression of microvascular endothelial cells (RBMECs). In this experiment, we use cultured rat brain microvascular endothelial cells (RBMECs). By using the parallel plate flow chamber method, we give two magnitudes of lamminar shear stresses (0.2 dyn/cm2, 0.4 dyn/cm2) for different perieods of time on the slides of cells. Immunostaining method and image analysis shows a specific upregulation in ICAM-1 expression on RBMECs, which is different from endothelial cells of other species or vascular beds. Expression of ICAM-1 is increased 0.5h after the onset of SS, and reached its highest level 4h after onset of SS, then declines after that. The effect is time-dependent, not force magnitude-dependent. Endothelial cell surface expression of ICAM-1 in the supernatants of RBMECs exposed to SS was not modified excluding the possibility that RBMECs exposed to SS synthesize factors that upregulate ICAM-1. The experiment data are relevant to the current understanding of basic mechanisms that explain the signal transudation pathway occurring inside the endothelial cells under the effect of SS.

Animals↗
PubMed2001

[Modification of the Photobacterium phosphoreum toxicity test method].

In order to reduce the variation of Photobacterium phosphoreum luminous intensity during testing, the Photobacterium phosphoreum toxicity test was modified by a correction factor, PIacetone, in this paper. The effects of magnetic stirring time, culture time, culture generation and culture temperature on the measured results were discussed. The modified method had good laboratory repeatability and the relative standard deviation (RSD) was between 2.1% and 13.1%. Reliable data could be obtained using the modified method. It would be beneficial to the development of the quantitative structure-activity relationships on multicomponent organic compounds.

Luminescent Measurements↗
PubMed2001

[The growth hormone and insulin-like growth factors axis in liver failure patients].

OBJECTIVE: To measure circulating concentration of growth hormone (GH), insulin-like growth factors 1 (IGF-1), and it's binding protein 1 (IGFBP1) and binding protein 3 (IGFBP3) in patients with sever hepatitis, and to survey the clinical significance of GH-IGFS axis. METHODS: The study population consisted of 18 patients with liver failure caused by serious virous hepatitis, and of 20 normal volunteers. Serum concentration of GH, IGF-1, IGFBP1 and IGFBP3 was determined by ELISA. Liver biochemistric functions were measured by routine methods. RESULTS: Serum concentrations of IGF-1 and IGFBP3 were equally reduced (5.5microgram/ml +/- 6.2 microgram/ml vs 17.6 microgram/ml +/-7.0 microgram/ml, and 2.4 microgram/ml +/-1.3 microgram/ml vs 9.4 microgram/ml +/- 1.7microgram/ml, P<0.001, respectively); increased serum GH and IGFBP1 were observed (9.1ng/ml +/-12.4ng/ml vs 1.6ng/ml +/-2.4ng/ml, P<0.05; 67.9ng/ml+/-50.2ng/ml vs 45.8ng/ml+/-33.1ng/ml, P<0.01) in liver failure patients as compared with the controls. The positive relationship between IGF-1 and IGFBP3 (r=0.91, P<0.001) was observed. The closed relation between the serum IGF-1 and the prognosis of patients was also obtained. IGF-1<10 microgram/ml was in accord with 90% accurate rate of predicted death. CONCLUSIONS: The GH-IGFs axis is significantly abnormal in liver failure patients, suggesting the existence of GH resistance in these patients. Serum IGF-1 may act as a predictor for their prognosis.

Adult↗
PubMed2001

Distribution of aluminum species and the characteristics of structure of poly-aluminum-chloride-sulfate(PACS).

A series of poly-aluminum-chloride-sulfate (PACS), which has different basicities (gamma) and Al3+/SO4(2-) molar ratio, has been prepared and dried at 105 degrees C and 65 degrees C, respectively. The distribution of aluminum species of PACS was examined, and the effect of gamma value, Al3+/SO4(2-) molar ratio, dilution on the distribution of aluminum species of PACS was also investigated by using Alferron timed complex colorimetric method. The IR spectroscopy and X-ray diffraction were used to study the effect of gamma value, Al3+/SO4(2-) molar ratio and the drying temperature on the structure of PACS. The experimental results show that Al3+/SO4(2-) molar ratio has a great effect on the distribution of aluminum species, but the dilution has a little effect on the distribution of aluminum species. The lower the Al3+/SO4(2-) molar ratio, the higher the proportions of the polymer and colloidal species in PACS. The polymeric degree of PACS was related to gamma value and Al3+/SO4(2-) molar ratio. Drying temperature has an influence on the structure and the solubility of solid PACS products.

Alum Compounds↗
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↗
PubMed2000

Design, synthesis, and monoamine transporter binding site affinities of methoxy derivatives of indatraline.

A series of methoxy-containing derivatives of indatraline 13a-f and 17 were synthesized, and their binding affinities for the dopamine, serotonin, and norepinephrine transporter binding sites were determined. Introduction of a methoxy group to indatraline affected its affinity and selectivity greatly. Except for the 4-methoxy derivative 13a,which had the same high affinity at the dopamine transporter binding site as indatraline, the other methoxy-containing analogues (13b-f and 17) exhibited lower affinity than indatraline for the three transporter binding sites. However, some of the analogues were more selective than indatraline, and the 6-methoxy derivative 13c displayed the highest affinity for both the serotonin and norepinephrine transporters. This compound retained reasonable affinity for the dopamine transporter and is a promising template for the development of a long-acting inhibitor of monoamine transporters. Such inhibitors have potential as medications for treatment, as a substitution medication, or for prevention of the abuse of methamphetamine-like stimulants.

Animals↗