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Biomedical subjects

H Zhong

Publications and source records attributed to H Zhong.

At least 127 records · Page 7Linked to original sources
PubMed1997

[99mTc-MIBI myocardial perfusion imaging in patients with diabetes].

Seventy-four patients with diabetes were taken on both stress and rest 99m-Tc-MIBI SPECT imaging: 44 patients (59.5%) were found having myocardial ischemic disorders, including 28 cases of myocardial ischemia, 7 cases of myocardial infarction and 9 cases of both conditions. 113 segments were involved and 46% were located in the posterior and inferior walls, indicating that the right coronary artery is most susceptive to ischemia. Diabetic patients complicated hypertension and/or hyperlipidemia were at higher risk of either early occurrence of coronary disease. 99mTc-MIBI SPECT imaging is helpful in early diagnosis and therefore is significant in directing.

Adult↗
PubMed1997

[Effects of low concentration carbon monoxide on human physiological function].

Human volunteers were exposed to various low concentrations of carbon monoxide (CO) in a closed cabin. The results showed that 35 mg/m3 of CO caused slight subjective symptoms and reduction in contrast vision, operating efficiency and T-wave of ECG. At 80 mg/m3 and 115 mg/m3 the above changes were more severe and a rise in hearing threshold level was observed. It demonstrated that an inhibitory effect on the CNS and heart were caused by low concentrations of CO. According to the absorption curves for human exposed to CO, it is suggested that the sense effect level and vision effect level for CO are 7% COHb, and the hearing effect level is 9% COHb.

Aerospace Medicine↗
PubMed1997

[Preliminary study on the arsenic trioxide-induced NB4 cell apoptosis and its molecular mechanisms].

OBJECTIVE: To illustrate the possible cellular and molecular mechanisms of arsenic trioxide (As2O3) in the treatment of acute promyelocytic leukemia (APL). METHODS: APL cell line NB4 was used for in vitro studies. The effect of As2O3 on APL was studied by using flow cytometry, DNA electrophoresis, Narthern blotting and Western blotting. RESULTS: As2O3 induced NB4 cell apoptosis, while not inhibiting the growth and survival of two other leukemic cell lines (HL-60 and U937). Furthermore, As2O3 effectively down-regulated the expression of bcl-2 gene without changing the mRNA levels of other apoptosis-associated genes (including p53, c-myc, bax and bcl-XL). CONCLUSION: These might be one of the molecular mechanisms of As2O3 induced NB4 cell apoptosis.

Animals↗
PubMed1997

[Effects of arsenic trioxide on the subcellular localization of PML/PML-RARalpha protein in leukemic cells].

OBJECTIVE: In order to illustrate the possible roles of PML-RARalpha protein in arsenic trioxide (AsO3)-induced NB4 cell apoptosis. METHODS: Effects of As2O3 on the subcellular localization of PML-RARalpha in NB4 cells were studied. RESULTS: (1) Anti-PML serum staining was reduced and PML granules emerged in the perinuclear cytoplasm in a diffuse pattern in HL-60 cells under As2O3 treatment; (2) abnormal PML/PML-RARalpha granules were decreased; (3) NB4 cells accumulated anti-PML serum staining granules in the cytoplasms were increased and similar accumulation also found in apoptotic cells; and (4) pretreatment with all-trans retinoic acid (ATRA) for 24 or 48 hours did not alter the As2O3 effects. CONCLUSION: As2O3-induced apoptosis was independent of the retinoic acid signal pathway, and it might be regulated by PML/PML-RARalpha and/or other related genes.

Antineoplastic Agents↗
PubMed1997

[Comparative study of two fusion retinoic acid receptor alpha in acute promyelocytic leukemia].

OBJECTIVE: To make a comparison of biological properties between PML-RARalpha and PLZF-RARalpha fusion proteins. METHODS: Receptor radioligand binding assay, receptor DNA binding assay and immunofluorescence methods were used. RESULTS AND CONCLUSION: PML-RARalpha and PLZF-RARalpha had similar ligand-binding affinities. Both could bind in vitro to retinoic acid response elements (RAREs) forming homodimers and to retinoic acid X receptor. However ,they differed in the relative binding affinities to different RAREs,the behavior of forming complex with RXR and the subcellular localization. More importantly, PML-RARalpha and PLZF-RARalpha could block different regulatory pathways mediated by PML or PLZF, through heterocomplex formation with wild-type PML or PLZF. The differences between PML-RARalpha and PLZF-RARalpha may in part explain the apparent resistance of APL with t(11;17) to differentiating effect of all-trans retinoic acid (ATRA).

DNA↗
PubMed1997

[Application of wavelet transform to the isolation of EXAFS oscilations from experiment data].

It is of significant importance to isolate lambda(k) form the total absorption cofficient data micro(E) for the analysis of EXAFS spectrum. Generally, least-squares procedure of polynomial spline or B spline was used for removing the smooth sbsorption background, which has been proved to be effective. But it suffers in that the trial of knot points is time-consuming and it is poor in reproducibility. In this paper, a new chemometrics method--wavelet transform analysis was used to separate the lambda(k) and background absorption from micro(E) and it is proved that the technique is a very good method for the analysis of EXAFS spectrum.

English Abstract↗
PubMed1997

[The plasma levels of endothelin in diabetic retinopathy and their changes after treatment with doxium].

The plasma endothelin (ET) concentrations were determined in 45 diabetes mellitus patients. The changes of ET in 20 diabetic retinopathy patients before and after treatment with doxium and 30 normal controls were observed. The level of plasma endothelins was higher in diabetes mellitus patients than that of the controls (P < 0.05), which was even higher in diabetic retinopathy (P < 0.01). After treatment with doxium, the plasma endothelins level decreased significantly (P < 0.01).

Adult↗
PubMed1996

The effects of 5'-N-ethylcarboxamidoadenosine on evoked release of [3H]serotonin in the rat nucleus tractus solitarius.

5'-N-Ethylcarboxamidoadenosine (NECA) a non-selective adenosine A1 and A2a receptor agonist was employed in stimulated (3 Hz, 25 mA, 1 min) superfused nucleus tractus solitarius (NTS) brain slices loaded with [3H]5-hydroxytryptamine ([3H]5-HT), and ligand binding with [3H]NECA on NTS membranes. Superfusion of NTS slices with 1.0 and 3.0 nM NECA for 5 min prior to S2 stimulation produced an augmented release of [3H]5-HT (35.7%) above the control S2/S1 ratio. When the duration of NECA perfusion was increased to 20 min prior to S2, the S2/S1 ratio was depressed 21% at 1.0 nM for [3H]5-HT release. The augmented release of [3H]5-HT by NECA at 5 min was blocked by the adenosine A2a antagonist 8-(3-chlorostyryl)caffeine (CSC; 100 nM), and was reduced but not blocked by the A1 antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 10 nM). Saturation binding assays with [3H]NECA on NTS membranes showed two binding sites, a high affinity site with a KD 2.18 nM and low affinity site with a KD of 44.9 nM. With the selective adenosine A2a antagonist CSC the high affinity site was blocked while 10 nM DPCPX, the A1 antagonist, reduced binding of the low affinity site, but did not abolish it. NECA binds to two different adenosine receptor sites in NTS membranes with the A2a receptor being the high affinity site. The same A2a site is associated with the augmented neurotransmitter release of [3H]5-HT with 5 min tissue exposure since it is blocked by CSC. Longer tissue exposure to NECA resulted in desensitization and finally inhibition of release possibly associated with adenosine A1 receptors.

2-Chloroadenosine↗
PubMed1996

The yeast alpha2 and Mcm1 proteins interact through a region similar to a motif found in homeodomain proteins of higher eukaryotes.

Homeodomain proteins are transcriptional regulatory factors that, in general, bind DNA with relatively low sequence specificity and affinity. One mechanism homeodomain proteins use to increase their biological specificity is through interactions with other DNA-binding proteins. We have examined how the yeast (Saccharomyces cerevisiae) homeodomain protein alpha2 specifically interacts with Mcm1, a MADS box protein, to bind DNA specifically and repress transcription. A patch of predominantly hydrophobic residues within a region preceding the homeodomain of alpha2 has been identified that specifies direct interaction with Mcm1 in the absence of DNA. This hydrophobic patch is required for cooperative DNA binding with Mcm1 in vitro and for transcriptional repression in vivo. We have also found that a conserved motif, termed YPWM, frequently found in homeodomain proteins of insects and mammals, partially functions in place of the patch in alpha2 to interact with Mcm1. These findings suggest that homeodomain proteins from diverse organisms may use analogous interaction motifs to associate with other proteins to achieve high levels of DNA binding affinity and specificity.

Amino Acid Sequence↗
PubMed1996

[Study on changes of visual fatigue index during prolonged visual display terminal operation].

25 Arabic numerals (0-9) lined in a row were displayed with 4 different patterns on CRT. The subjects were asked to find out the one missed numeral in the row and to press the key corresponding to the numeral. The work lasted for 3h. Longitudino-Kinetic visual acuity was measured before and at 30, 60, 80, 100, 120, 150, 180 minutes during the work. The results showed that the Longitudino-Kinetic visual acuity dropped with working time and recovered after work quickly at first and then slowly.

Asthenopia↗
PubMed1996

Inducible expression of beta 1- and beta 2-adrenergic receptors in rat C6 glioma cells: functional interactions between closely related subtypes.

We examined the role of beta 1- and beta 2-adrenergic receptor (AR) density and ratio in catecholamine-stimulated cAMP responses in rat C6 glioma cells. These cells, which normally express both subtypes, were stably transfected with an isopropylthio-beta-D-galactoside-inducible vector containing either beta 1AR or beta 2AR coding sequences, and receptor expression was controlled by the time and concentration of isopropylthio-beta-D-galactoside exposure. Induction of the dominant beta 1AR subtype increased the potencies of isoproterenol (ISO) and other agonists in stimulating cAMP accumulation by 20-40-fold without changing maximal response. Induction of beta 2AR expression caused 7-13-fold increases in the potency of ISO, epinephrine, and zinterol, but not of norepinephrine, and a 20-40% loss in maximal response to all agonists. Selective antagonists showed that both subtypes contributed in a nonadditive manner in the response to ISO under different conditions. After beta 2AR induction, the effects of ISO were not blocked by the beta 1-selective antagonist CGP 20712A but were shifted 100-fold to the right by the beta 2-selective antagonist ICI 118,551. However, in the presence of ICI 118,551, CGP 20712A caused an additional 100-fold decrease in ISO potency, and Schild analysis revealed complex interactions between the two subtypes. Each antagonist alone caused smaller shifts to the right in the dose-response curve to NE and, when present simultaneously, completely abolished the NE response. We conclude that beta 1ARs and beta 2ARs have different efficiencies in activating cAMP accumulation in C6 glioma cells. Activation of coexisting subtypes results in complex and sometimes synergistic interactions between the two subtypes, which vary with agonist concentration, selectivity, subtype density, and ratio.

Adrenergic beta-Agonists↗
PubMed1996

[IL-6 gene expression in human tumor cell lines].

Using Northern blot techniques and IL-6-dependent cell line proliferating response method, the IL-6 gene expression in 8 sorts of human tumor cell lines and the IL-6 biologic activity in 5 sorts of medium were investigated. The results revealed that IL-6mRNA was positively expressed in 7 sorts of these cell lines and there were differential IL-6 biologic activity in 5 sorts of assayed medium. These results may providea basis for further research.

Blotting, Northern↗
PubMed1996

[Expression of basic fibroblast growth factor and its receptor in renal cell carcinoma].

Basic fibroblast growth factor (bFGF) is a pluripotent polypeptide which plays an important role in tumor progression and angiogensis. We determined the expression and localization patterns of bFGF and one of its receptor (FGFR-1) in normal renal as well as in renal cancers. The results were compared with clinicopathologic features. Using bFGF and FGFR-1 antibody, the repairing method of antigen with microwave oven heating and LSAB immunohistochemistry we used in 36 cases of paraffin-embedded renal cell carcinoma (RCC) and their paired normal renal tissues. The expression of bFGF and FGFR-1 was nearly consistent. The normal renal tissues and ECM of 29 cases of renal cancer tissues showed heterogenous immunoreactivities. Renal cancer cell cytoplasm of 12 primary tumors and 2 metastatic tumors, as in the cytoplasmic bFGF of cultured GRC-1 cells, were positively homogenous stained. The bFGF and FGFR-1 can be consistently expressed in normal renal and renal cancer tissues, reflecting that the expression and function of these substances were closely associated. The cytoplasmic bFGF expression of renal cancer was related to tumor stages, suggesting that b bFGF plays an important role in the progression of renal cell carcinoma.

Adenocarcinoma, Clear Cell↗
PubMed1995

Basic fibroblast growth factor regulates ionic currents and excitability of fetal rat carotid body chemoreceptors.

Basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) are known mitogens and/or differentiation factors for cells of the sympathoadrenal lineage. Though carotid body (CB) chemoreceptors (type 1 cells) are considered part of this lineage, their response to bFGF is unknown and so far they appear unresponsive to NGF in vitro. In this study we use whole-cell recording to investigate whether bFGF (and NGF) can influence the development of ionic currents in these chemoreceptors, cultured from fetal (E18-19) rat pups. bFGF (10ng/ml) significantly augmented both transient inward Na+ and outward K+ currents in type 1 cells after only 2 days of treatment; after normalizing for the accompanying increase in cell size, as indicated by whole-cell capacitance, the Na+ current density was nonetheless increased by bFGF. Unlike controls, bFGF-treated type 1 cells readily fired action potentials following depolarization. These effects were not mimicked by NGF (100 ng/ml) treatment. Since the carotid body is one of the most richly vascularized organs and bFGF is a potent angiogenic factor, it is conceivable that variations in local bFGF concentrations during fetal development may contribute to the known species differences in CB chemoreceptor excitability.

Animals↗