Biomedical subjects

H Zhou

Publications and source records attributed to H Zhou.

At least 289 records · Page 16Linked to original sources

PubMed2000

Cloning of Chinese obese cDNA and its expression in E. coli.

OBJECTIVE: To obtain the sequence of Chinese obese (OB) cDNA and establish a method of leptin production in China. METHODS: Han Chinese OB cDNA fragment was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR) with total RNA extracted from human adipocytes and was inserted into the expressing vector pBV220. Then the constructed recombinant plasmid pBV220-OB was transformed to E. coli DH5 alpha for leptin expression. The recombinant expressing system was confirmed by restriction endonuclease digestion, DNA sequencing and protein expression. E. coli cells were lysed by high-pressure homogenization. After cell membrane was extracted, the inclusion bodies were mainly renatured and purified primarily by precipitation with ammonium sulfate and gel chromatography through a Sephadex G75 column. The activity of recombinant leptin was determined by its influence on the satiety and weight gain of mice. RESULTS: Analysis of DNA sequence showed that Han Chinese OB cDNA included the glutamine codon at 49. The amount of recombinant leptin expressed in E. coli accounted for 31%-47% of total cellular proteins. From 1 L of fermentative bacteria about 40 mg of pure recombinant human leptin was isolated with a purity of being above 95%. The recombinant human leptin could reduce food intake and inhibit weight gains in mice. CONCLUSION: The glutamine codon at 49 is not missing in Chinese OB gene. The biologically active human leptin can be obtained by a relatively simple method of recombinant DNA technology.

Animals↗

PubMed2000

Apoptosis of infiltrating cells in experimental autoimmune uveoretinitis.

OBJECTIVE: To investigate the cellular phenotype and apoptosis of infiltrating cells involved in experimental autoimmune uveoretinitis (EAU). METHODS: Immunohistochemical staining and in situ apoptosis staining were performed using monoclonal antibodies to monocytes and macrophages (ED1), major histocompatibility complex (MHC) class-II antigen (OX6), T lymphocytes (R73) and TACS 1 Klenow kit on both ocular sections and wholemounts from Lewis rats after immunization with interphotoreceptor retinoid-binding protein (IRBP). RESULTS: EAU was induced in 12 of 16 Lewis rats with a mean clinical inflammation score of 1.29 +/- 0.7. Influx of monocytes, lymphocytes and MHC class II-positive cells into the uvea and retina was noted after immunization with IRBP. Apoptosis of infiltrating cells was observed in the uvea and retina, and more apoptotic cells were present in the iris and ciliary body compared with those in the choroid and retina. CONCLUSION: Apoptosis of infiltrating cells occurs at the early stage of EAU, which may greatly contribute to the rapid regression of the inflammation induced by IRBP.

Animals↗

PubMed2000

[Surgical treatment of cervical lymph nodes in 301 patients with oral squamous cell carcinoma].

OBJECTIVE: To evaluate cervical lymph metastases and its surgical treatment of oral carcinoma with regard to primary location and TNM classification. METHODS: 301 previously untreated patients were included in the follow-up study to calculate the rate of histopathologically positive lymph metastasis and the rate of recurrences in untreated necks and after FND (functional neck dissection). RESULTS: Lymph node pathologic positive rates were N0 7.4%, N1 14.7%, N2 76.2%. Recurrences occurred in 32.1% untreated necks and 14.7% necks after FND of carcinomas of tongue, buccal, lower-gingiva and oral floor, while rarely in necks of carcinomas of palate and upper-gingiva. CONCLUSIONS: TNM classification is useful to estimate lymph metastasis. Application of elective neck dissection needs to expand in carcinomas of the above four sites. It should be careful when choose FND.

Adult↗

PubMed2000

[Serial cultivation of normal human oral keratinocytes].

OBJECTIVE: To establish a method of culturing normal human oral keratinocytes. METHODS: Specimens obtained from healthy humans undergoing oral surgery were dissociated by Dispase and trypsin into a single cell suspension. The cells were grown in serum-free medium. Morphological characteristics were studied under light microscope and electron microscope (EM). Cytokeratins were showed by immunohistochemistry. RESULTS: The cells could be maintained in culture up to 4-5 passages, or 30-50 days. EM revealed that there were desmosomes and tonofibrils in the culture cells. The cells showed positive staining for cytokeratin antibody. CONCLUSIONS: The culture technique for growing normal human oral keratinocytes has been established.

Cell Culture Techniques↗

PubMed2000

[The value of nuclide myocardial scintigraphy for the clinical of acute viral myocarditis].

OBJECTIVE: To investigate the significance of nuclid myocardial scintigraphy (ECT) as a clinical method for guiding the diagnosis, therapy and prognosis of a cute viral myocarditis. METHODS: 48 patients with acute viral myocarditis were divided into two groups, 21 patients with ECT showing diffuse myocardial perfusion defect constituted a positive group and the remaining 27 with normal ECT a negative group. The relationship between the clinical data and treatment effect in the two groups were analyzed. RESULTS: In the positive group, CK-MB in 57.14% of the patients was higher than normal and 71.43% of the patients had ventricular premature beats (VPB) and atrial premature beats (APB). The average number of VPB per 24 hour was (4228 +/- 1506) beats. In the negative group, the values of the above items were 33.33%, 44.44% and (2268 +/- 924) beats. The difference between the two groups was statistically significant (all of P < 0.01). After treatment of acute viral myocarditis, ECT of all the patients in the positive group returned to normal completely 85.71% of the patients with premature beats recovered from the arrhythmia. 38.10% of the patients with premature beats had arrhythmia again during a follow-up of 4 years. However, in the negative group, only 59.26% of the patients with premature beats recovered from the arrhythmia and 66.67% had arrhythmia again during the 4 years. The therapeutic effect between the two groups was also statistically different (all of P < 0.01). CONCLUSION: Up to now, there has been no unified diagnostic standard for acute viral myocarditis, so ECT may be an exact and reliable diagnostic method for acute viral myocarditis. It may help to avoid error in diagnosis, waste in health resources and side effects of the medications.

Acute Disease↗

PubMed2000

[The contribution of phacoemulsification to combined cataract and glaucoma surgery].

OBJECTIVE: To study the safety and effectiveness of phacoemulsification (phaco) in trabeculectomy combined with cataract extraction (phacotrabeculectomy) and posterior chamber intraocular lens (IOL) implantation. METHODS: 68 eyes with glaucoma and cataract were randomly divided into two groups: the phacotrabeculectomy with IOL implantation and modern extracapsular cataract extraction (ECCE), trabeculectomy and IOL implantation. RESULTS: Postoperatively, in the phaco group, the intraocular pressure (IOP) decreased obviously at the early stage (P < 0.05), the number of cases necessary for the use of anti-glaucoma drug was decreased, the mean kinds of the drug applied were markedly decreased (P < 0.05), the visual acuity improved quickly, significantly and steadily, and the complications were less than that in the ECCE group. CONCLUSIONS: The phaco's triple surgery is safe and effective. In cases with glaucoma and cataract, the surgery is indicated even when the cataract is not mature or premature.

Aged↗

PubMed2000

[Epidemiological feature on diabetes mellitus among permanent inhabitant in the Special Economic Zone of Shenzhen].

OBJECTIVE: To investigate prevalence and relevant factors of diabetes mellitus among permanent inhabitant in Shenzhen. METHODS: The prevalence of 8 200 inhabitants aged over 20 in Shenzhen was studied. Blood glucose was determined by glucose - oxidase method. RESULTS: According to the WHO diagnostic standard, the prevalence rates of DM and IGT were 4.23% and 11.94% respectively. The prevalence increased apparently with age. The history of clan and overweight were related to the prevalence rates of DM and IGT. The people of DM and IGT were mostly accompanied with high levels of triglyceride, total cholesterol, uric acid, creatinine and low level of high dense lipoprotein (HDL). CONCLUSION: The history of clan, old age, overweight and higher fattiness were found risk factors of DM and IGT.

Adult↗

PubMed2000

[Risk factors of type 2 diabetes in Shenzhen].

OBJECTIVE: The study was designed to investigate the risk factors of Type 2 diabetes in the new city Shenzhen. METHODS: A representative sample of 8,182 adults aged over 20 to 75 years old were randomly selected in the residents of Shenzhen, China in 1997. Type 2 diabetes was diagnosed according to the WHO criteria. Questionnaire survey, anthropometric measurement and blood analysis were carried out, and logistic regression analysis was used to study the risk factors. RESULTS: The results showed that the prevalence of type 2 diabetes in subjects with high total cholesterol were 4.9 times of those with lower TC value. Subjects with high triglyceride had a prevalence 5.7 times of those who had lower TG. Those HDL-ch had a prevalence 68.7% higher than those with normal HDL-ch value; on the other hand, those HDL-ch > 1.91 mmol/L were 44.6% lower in the prevalence than those with normal HDL-ch. The prevalence of type 2 diabetes in subjects with BMI >or= 25 were 2.6 times of those with BMI < 25. Subject with hypertension (>or= 140/90 mm Hg) had a prevalence 3.8 times of those with normal blood pressure. Subjects with family history of type II diabetes had a prevalence 2.0 times of no family history, and women who had delivered babies over 4 kg had a prevalence 1.9 times of those who had babies less than 4 kg. Subjects with waist/hip ratio (WHR) >or= 1.0 had a prevalence 5.1 times of those with WHR < 1.0. The prevalence of type 2 Diabetes was higher with increasing amount of cigarette smoking and the duration (in years) of smoking or increasing drinking (alcohol) and the duration (in years) of drinking. CONCLUSIONS: The blood glucose level was found to be positively correlated with TC or TG, and negatively correlated with HDL-ch. This study demonstrated again that TC, TG, HDL-ch, obesity, hypertension, family history of type 2 diabetes and in women, delivery of babies over 4 kg and age were risk factors of type 2 diabetes.

Adult↗

PubMed2000

[Impacts of clinicopathologic parameters on lymphatic metastasis of oral squamous cell carcinoma].

OBJECTIVE: To evaluate the effects of clinicopathologic parameters on lymphatic metastasis of oral squamous cell carcinoma. METHODS: One hundred and ninety-three patients who underwent therapy in our department were included in this study. Ten parameters (T and N stages, location, patterns of invasion, thickness, lymphocyte infiltration, karyokinesis count, degrees of differentiation, degrees of cell keratinization and nuclear polymorph) were evaluated to determine their effects on lymphatic metastasis of oral carcinoma using univariate and multivariate analysis. RESULTS: By using the univariate analysis, five parameters (T and N stage, pattern and depth of invasion, lymphocyte infiltration) showed significant impacts on pathologic nodal metastasis. From multivariate analysis, however, only patterns of invasion were independent predictors of metastasis. Also, patterns of invasion were the only significant factors that influence the post-operative metastasis besides pattern of neck treatment. CONCLUSION: The pattern of invasion is the most important parameter that influences the metastasis of oral squamous cell carcinoma.

Adult↗

PubMed2000

[Studies on quantitative chromatographic retention-structure relationships].

Using quantum and molecular mechanics methods, 48 structural descriptors of alkylbenzene compounds such as atomic partial charge, dipole moment, molecular area, molecular volume etc. were calculated. GFA regression methods were applied to build a quantitative chromatographic retention-structure relationships equation. The equation have good fitness and strong predictivity. Principle structural factors that effect chromatographic retention of alkylbenzenes were discussed.

Alkylation↗

PubMed2000

Excitatory connections between spinal motoneurons in the adult rat.

OBJECTIVES: Dendro-dendritic and dendro-somatic projections are common between spinal motoneurons. We attempted to clarify whether there are functional connections through these projections. METHODS: Motoneurons were antidromically stimulated by the muscle nerve and recorded intracellularly to examine the direct interaction between them after the related dorsal roots had been cut. RESULTS: Excitatory connections, demonstrated by depolarizing potentials in response to muscle nerve stimulation, were found between motoneurons innervating the same muscle or synergistic muscles, but never between motoneurons innervating antagonistic muscles. These potentials were finely graded in response to a series of increasing stimuli and resistant to high frequency (50Hz) stimulation. CONCLUSIONS: These results indicate that excitatory connections, with certain specificity of spatial and temporal distribution, occur in the spinal motoneurons. It is also suggested that electrical coupling should be involved in these connections and this mechanism should improve the excitability of the motoneurons in the same column.

Action Potentials↗

PubMed2000

[The molecular structure and the arrangement changes of stilbazoles in the phase transition process studied by temperature-variable FTIR spectroscopy].

Hydrogen bonding is one of the principal intermolecular forces to enable the construction of supramolecular structures. By choosing an appropriate proton acceptor and a proton donor, stable intermolecular hydrogen bonds can form and affect or change the phase behavior of the donor and acceptor. We have obtained two intermolecular hydrogen bonded liquid crystals using the stilbazoles as the proton acceptor. In this paper we will research the molecular structure and the arrangement changes during the phase transition process of the stilbazoles by temperature variable FTIR spectroscopy. The results show that the number of the gauche conformation is increasing as the temperature increasing. When it is coming to the isotropic phase, the alkyl chain is in disorder. The frequency shift of carbonyl stretching bands has been found to be sensitive to the change of molecular conformation, inter and intramolecular interactions.

Hydrogen Bonding↗

PubMed2000

[Determination of trace amounts of copper by flow injection vapor generation AAS].

A method for the determination of copper by FI-VGAAS (flow injection vapor generation atomic absorption spectrometry) was developed. The sample solution containing trace amounts of o-phenanthroline and 0.1 mol.L-1 HNO3 was carried out by carrier of 0.1 mol.L-1 HNO3 and merged with sodium tetrahydroborate solution to produce the vapor species of copper, which got separation in gas-liquid separator and was detected in a quartz tube atomizer at 1000 degrees C. A detection limit of 1.8 micrograms.L-1 (3 sigma) of copper was obtained with a sampling frequency of 144/h using a sample volume of 500 microL. The precision RSD was 2.6% (n = 11) at the 100 micrograms.L-1 copper. The method was applied to the analysis of human hair and rice standard reference samples, the results were in good agreement with certified values.

Borohydrides↗

PubMed2000

[Sequential injection vapor generation atomic absorption spectrometric determination of mercury and arsenic].

A sequential injection vapor generation atomic absorption spectrometric (SI-VGAAS) method for the determination of mercury and arsenic was developed, characterized by reagent merging using a double-syringe pump and a multi-position selector valve. A sample throughput of 120 h-1 was achieved with 500 microL sample with a precision of 2.2% for mercury at 8.0 micrograms.L-1 (n = 11) and 1.4% for arsenic at 6.0 micrograms.L-1 (n = 11) levels and a detection limit of 0.15 microgram.L-1 for mercury and 0.07 microgram.L-1 for arsenic. The method was applied to the analysis of geochemical standard reference material GSS-5, and good agreement with the certified values were obtained.

Arsenic↗

PubMed1999

Tyrosine kinase inhibitors. 16. 6,5,6-tricyclic benzothieno[3, 2-d]pyrimidines and pyrimido[5,4-b-] and -[4,5-b]ĭndoles as potent inhibitors of the epidermal growth factor receptor tyrosine kinase.

Several elaborations of the fundamental anilinopyrimidine pharmacophore have been reported as potent and selective inhibitors of the epidermal growth factor receptor (EGFr) tyrosine kinase. This paper reports on a series of inhibitors whereby some 6,5-bicyclic heteroaromatic systems were fused through their C-2 and C-3 positions to this anilinopyrimidine pharmacophore. Although the resulting tricycles did not produce the enormous potency of some of the (5/6),6,6-bicyclic systems, the best of them had IC(50)s for the EGFr TK around 1 nM. Investigation of 4-position side chains in the indolopyrimidines confirmed that m-bromoaniline was an optimal substituent for potency. Investigation of substitution within the C-(benzo)ring of benzothienopyrimidines confirmed that introduction of an extra ring can change sharply the effects of substituents when compared to similar bicyclic nuclei, and only two substituents were found which even moderately enhanced inhibitory activity over the parent compound for this series.

Amino Acid Sequence↗

PubMed1999

Predicting cancer rates in astronauts from animal carcinogenesis studies and cellular markers.

The radiation space environment includes particles such as protons and multiple species of heavy ions, with much of the exposure to these radiations occurring at extremely low average dose-rates. Limitations in databases needed to predict cancer hazards in human beings from such radiations are significant and currently do not provide confidence that such predictions are acceptably precise or accurate. In this article, we outline the need for animal carcinogenesis data based on a more sophisticated understanding of the dose-response relationship for induction of cancer and correlative cellular endpoints by representative space radiations. We stress the need for a model that can interrelate human and animal carcinogenesis data with cellular mechanisms. Using a broad model for dose-response patterns which we term the "subalpha-alpha-omega (SAO) model", we explore examples in the literature for radiation-induced cancer and for radiation-induced cellular events to illustrate the need for data that define the dose-response patterns more precisely over specific dose ranges, with special attention to low dose, low dose-rate exposure. We present data for multiple endpoints in cells, which vary in their radiosensitivity, that also support the proposed model. We have measured induction of complex chromosome aberrations in multiple cell types by two space radiations, Fe-ions and protons, and compared these to photons delivered at high dose-rate or low dose-rate. Our data demonstrate that at least three factors modulate the relative efficacy of Fe-ions compared to photons: (i) intrinsic radiosensitivity of irradiated cells; (ii) dose-rate; and (iii) another unspecified effect perhaps related to reparability of DNA lesions. These factors can produce respectively up to at least 7-, 6- and 3-fold variability. These data demonstrate the need to understand better the role of intrinsic radiosensitivity and dose-rate effects in mammalian cell response to ionizing radiation. Such understanding is critical in extrapolating databases between cellular response, animal carcinogenesis and human carcinogenesis, and we suggest that the SAO model is a useful tool for such extrapolation.

Animals↗

PubMed1999

Radon, tobacco-specific nitrosamine and mutagenesis in mammalian cells.

The mutagenicity of 4-methylnitrosamine-1-3-pyridyl-1-butanone (NNK), either alone or in combination with low dose alpha particle irradiation, was examined using the human-hamster hybrid (A(L)) cell assay. NNK induced a dose-dependent toxicity in A(L) cells. In combination with a 25 cGy dose of alpha particles, the induced survival fraction fell within the statistical range of the calculated values assuming an additive interaction of the two agents. In addition, NNK is mutagenic in A(L) cells at the CD59 locus. Furthermore, a low dose of NNK, when combined with radon alpha particles, resulted in a combined mutagenic effect in A(L) cells that was consistent with an additive model but less than additive at higher NNK concentrations. The majority of NNK induced CD59(-) mutants (77.6%) lost at least one additional marker in addition to the CD59 which encodes the cell surface antigen. When combined with alpha particles, the proportion of mutants with additional marker loss increased with increasing dose of NNK. Our study further confirms that NNK is mutagenic in mammalian cells, induces mostly deletions, and provides an in vitro assessment of the combined genotoxic effects of NNK and alpha particles at low environmentally relevant doses. This finding should be helpful in understanding the molecular mechanism of the mutagenic process as a result of multi-agent interaction.

Alpha Particles↗

PubMed1999

Identification and dynamics of a heparin-binding site in hepatocyte growth factor.

Hepatocyte growth factor (HGF) is a heparin-binding, multipotent growth factor that transduces a wide range of biological signals, including mitogenesis, motogenesis, and morphogenesis. Heparin or closely related heparan sulfate has profound effects on HGF signaling. A heparin-binding site in the N-terminal (N) domain of HGF was proposed on the basis of the clustering of surface positive charges [Zhou, H., Mazzulla, M. J., Kaufman, J. D., Stahl, S. J., Wingfield, P. T., Rubin, J. S., Bottaro, D. P., and Byrd, R. A. (1998) Structure 6, 109-116]. In the present study, we confirmed this binding site in a heparin titration experiment monitored by nuclear magnetic resonance spectroscopy, and we estimated the apparent dissociation constant (K(d)) of the heparin-protein complex by NMR and fluorescence techniques. The primary heparin-binding site is composed of Lys60, Lys62, and Arg73, with additional contributions from the adjacent Arg76, Lys78, and N-terminal basic residues. The K(d) of binding is in the micromolar range. A heparin disaccharide analogue, sucrose octasulfate, binds with similar affinity to the N domain and to a naturally occurring HGF isoform, NK1, at nearly the same region as in heparin binding. (15)N relaxation data indicate structural flexibility on a microsecond-to-millisecond time scale around the primary binding site in the N domain. This flexibility appears to be dramatically reduced by ligand binding. On the basis of the NK1 crystal structure, we propose a model in which heparin binds to the two primary binding sites and the N-terminal regions of the N domains and stabilizes an NK1 dimer.

Animals↗