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Biomedical subjects

H Wei

Publications and source records attributed to H Wei.

At least 199 records · Page 11Linked to original sources
PubMed1995

Psychoactive substance use in three sites in China: gender differences and related factors.

One year prevalence rates for psychoactive substance use are reported based on a community survey in Hunan, Helongjiang and Jiangsu. Data were gathered on more than 14,000 respondents (15-65 years old). The drinking rates ranged from 58.3% to 82.6% for men and from 16.3% to 31.4% for women. Smoking rates ranged from 64.9% to 68.1% for men and from 0.1% to 20.5% for women. Most drinkers were light users and most smokers were heavy users. Illicit drug use was found in the Hunan site. For both frequency and quantity of psychoactive substance use, women are lighter consumers than males (except for the use of minor tranquillizers and analgesics). Psychosocial factors related to drinking and smoking are also investigated in this study.

Adolescent↗
PubMed1995

Some anti-allergic and anti-inflammatory actions of 2-N-carboxamidinonormianserin (FCC5).

The aims of these studies were to examine the effects of FCC5 (2-carboxamidino-1,2,3,4,10,14b-hexahydrodibenzo (c,f) pyrazino (1,2,-a) azepine HCl), an analogue of mianserin, on immediate type hypersensitivity reactions in-vitro. The actions of FCC5 were examined on the Schultz-Dale reaction of guinea-pig ileum and on histamine and leukotriene release from human- and guinea-pig-sensitized lung fragments. FCC5 (applied topically) was assessed for anti-inflammatory activity in-vivo against phorbol-12-myristate-13-acetate (PMA)-induced oedema in the mouse ear. FCC5 (IC50 = 0.17 microM) was a potent inhibitor of the Schultz-Dale reaction in-vitro, as assessed by a concentration-dependent attenuation of egg albumin-induced contractions of sensitized guinea-pig isolated ileum. Using human and guinea-pig isolated sensitized lung fragments, FCC5 (1-100 microM) attenuated antigen-induced release of sulphidopeptidoleukotrienes and histamine. FCC5 (50 micrograms topically) resembled mianserin and indomethacin in attenuating PMA-induced mouse ear inflammation. These properties together with previously published evidence of long lasting antihistamine properties in-vivo, suggest that FCC5 has therapeutic potential as an anti-allergic agent, especially in pathological conditions where an inflammatory component is present.

Analysis of Variance↗
PubMed1995

Antioxidant and antipromotional effects of the soybean isoflavone genistein.

Antioxidant and antipromotional effects of the soybean isoflavone genistein have been studied in HL-60 cells and the mouse skin tumorigenesis model. Effects of structure-related flavone/isoflavones on hydrogen peroxide (H2O2) production by 12-O-tetradecanoylphorbol-13-acetate (TPA)-activated HL-60 cells and superoxide anion (O2-) generation by xanthine/xanthine oxidase were compared. Of tested isoflavones, genistein is the most potent inhibitor among TPA-induced H2O2 formation by (dimethyl sulfoxide) DMSO-differentiated HL-60 cells, daidzein is second, and apigenin and biochanin A show little effect. In contrast, genistein, apigenin, and prunectin are equally potent in inhibiting O2- generation by xanthine/xanthine oxidase, with daidzein showing a moderate inhibitory effect and biochanin A exhibiting no effect. These results suggest that the antioxidant properties of isoflavones are structurally related and the hydroxy group at Position 4' is crucial in both systems. Dietary administration of 250 ppm genistein for 30 days significantly enhances the activities of antioxidant enzymes in the skin and small intestine of mice. Further studies show that genistein significantly inhibits TPA-induced proto-oncogene expression (c-fos) in mouse skin in a dose-dependent manner. In a two-stage skin carcinogenesis study, low levels of genistein (1 and 5 mumol) significantly prolong tumor latency and decrease tumor multiplicity by approximately 50%. We conclude that genistein's antioxidant properties and antiproliferative effects may be responsible for its anticarcinogenic effect. Its high content in soybeans and relatively high bioavailability favor genistein as a promising candidate for the prevention of human cancers.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

A GOD electrode free from the influence of ethanol.

The influence of ethanol on GOD electrode was investigated. When enzyme electrode was made by the Sandwich method, 0.1% (V/V) ethanol had an obvious influence on the response of the electrode with 4.3% deviation. The influence increased with increasing ethanol content of the samples. This influence can be avoided by using a nylon mesh GOD electrode, which was successfully used for the determination of glucose in the range of 5-20 mM with ethanol content up to 9% (V/V). Such an electrode showed good reproducibility, stable response activity and long storage life ( > 30 days).

Biosensing Techniques↗
PubMed1995

[Constituents of the petroleum ether and ethyl acetate extract fractions from Dracaena cochinensis (Lour.) S.C. Chen].

Six constituents have been isolated from the petroleum ether and ethyl acetate extract fractions of Dracaena cochinensis. Their structures have been identified as 1,2,4,5-tetrachloro-3,6- dimethoxy-benzene,docosyl alcohol, octadecyl acetate, eicosyl acetate, resveratrol and 4',7-dihydroxy-flavone on the basis of physical, chemical and spectral deta. Of these compounds 1,2,4,5-tetrachloro-3,6-dimethoxy-benzene is a new one.

Chlorobenzenes↗
PubMed1995

Role of vasogenic edema and tissue cavitation in ischemic evolution on diffusion-weighted imaging: comparison with multiparameter MR and immunohistochemistry.

PURPOSE: To examine the mechanisms of further evolution that occurs from the early to late phase after initial changes in diffusion-weighted imaging after cerebral ischemia. METHODS: Sprague-Dawley rats were subjected to middle cerebral artery occlusion. Diffusion-, proton density-, T1- and T2-weighted imaging were performed on days 0, 2, and 6. Histologic examination (IgG, glial fibrillary acidic protein, and cresyl violet staining) was done after scanning. RESULTS: Apparent diffusion coefficients (ADCs) in the ischemic hemisphere were significantly decreased on day 0. Thereafter, ADCs increased over time and became significantly higher than the contralateral side by day 6. Changes in basal ganglia occurred more rapidly than in cortex. Proton density-, T1-, and T2-weighted scans showed maximal changes on day 2. From day 0 to day 2, there are significant correlations between changes in ADC and changes in T1-weighted signals and T2-weighted signals. Histologic exam showed early neuronal injury on day 0, intense gliotic activity and protein leakage associated with infarction and edema on day 2, and cavitation in severely infarcted areas on day 6. CONCLUSION: After initial reduction of ADC, the subsequent increase in ADC values on day 2 may be associated with vasogenic edema and cell lysis. Later elevations in ADC may be related to cavitation of infarcted tissue.

Animals↗
PubMed1995

[A morphological study of experimental corneal neovascularization].

Corneal neovascularization (CNV) was induced by alkali burn injuries in 20 rabbit corneas. The process of CNV was observed with biomicroscopy in vivo and histologically by light and electron microscopy. At 8 hours after injury, an obvious acute inflammatory response as evidenced by infiltration of neutrophils had already occurred in the pericorneal limbal area. Many neutrophils in the extravascular space contained abundant intracytoplasmic phagolysosomes. The vascular sprouts appeared 2 days after injury. The infiltration of neutrophils and their debris were visible around newly formed blood vessels in the cornea. The results suggest that there be the participation and an inductive action of neutrophils in the pathogenesis of CNV.

Animals↗
PubMed1995

[Effect of RU486 on metabolism of glycosaminoglycans in the cultured calf trabecular meshwork cells].

The trabecular meshwork from newborn bovine eyes was used for cell culture and subculture to the third passage. Then the concentrations of RU486, a corticosteroid antagonist, in the medium were made to be 50, 100 and 200 micrograms/ml and 3H-glycosamine was introduced as the radioactive precursor. After extraction and purification, an aliquot of glycosaminoglycans (GAGs) was used for cellulose acetate electrophoresis, sequential degradation by different enzymes and radioactivity determination by scintillation counting to determine the total amount of GAGs and the amounts of constituents, such as hyaluronic acid (HA), etc. In the control group, the total amount of GAGs was 980 DPM/micrograms cell prot (disintegration per minute/micrograms cell protein) and HA accounted for 17.8%, while in the medium of 50 micrograms/ml and 100 micrograms/ml RU486, HA was increased to 50.1% and 46.1%, respectively. In the medium of 200 micrograms/ml RU486, the total amount of GAGs was decreased to 695 DPM/micrograms cell prot. The results were consistent with the theory of pharmacology and pharmacodynamics. It is possible that the corticosteroid antagonist can be used to reverse the pathogenesis of primary open-angle glaucoma.

Animals↗
PubMed1994

The cloning and expression of a human creatine transporter.

A human creatine transporter (hCRT-BS2M) cDNA clone was isolated from a human brainstem/spinal cord using a PCR and phage plaque hybridization based technique. This clone included an open reading frame of 1,905 base pairs(bp) within a 2,283bp cDNA. Northern blot hybridization detected the expression of corresponding mRNAs most prominently in the skeletal muscle, heart and kidney. Peptide sequence analysis of the hCRT-BS2M protein product revealed 12 putative transmembrane domains. The predicted protein sequence further demonstrates that the hCRT-BS2M has highly conserved amino acid identity with the other members of the sodium dependent plasma membrane transporter family. Transient expression of the hCRT-BS2M in COS-7 cells demonstrates sodium dependent [14C]creatine uptake with a KM value of 14.9 +/- 3.0 microM (n = 5) that is attenuated by creatine and selective structural analogues of creatine.

Amino Acid Sequence↗
PubMed1994

Autoradiographic analysis of L- and N-type voltage-dependent calcium channel binding in canine brain after global cerebral ischemia/reperfusion.

Binding of antagonists to L- and N-type voltage-dependent calcium channels (VDCC) was measured in canine brain following global ischemia and reperfusion. Ischemia was induced by 10 min cardiac arrest, followed by restoration of spontaneous circulation for periods of up to 24 h. Binding of [3H]PN200-110 and [125I]omega-conotoxin GVIA to frozen sections from hippocampus, striatum, parietal cortex and temporal cortex was analyzed using quantitative receptor autoradiography. The binding patterns of the two radioligands were similar in cortex and striatum, but differed in hippocampus. In the latter tissue, [125I]omega-conotoxin GVIA binding was dense over synaptic regions, especially the presynaptic polymorph layer of the dentate gyrus, but was virtually absent over cell body layers. In contrast, [3H]PN200-110 binding was more homogenously distributed, with highest binding in the molecular layer of the dentate gyrus. The binding of [125I]omega-conotoxin GVIA was not different from sham controls at any time point following cardiac arrest. [3H]PN200-110 binding was decreased in each region immediately following ischemia, recovering within 30 min of recirculation. These findings are in contrast to earlier findings of rapid increases in L-type VDCC binding to membrane fractions obtained from cortex and striatum in this model, and suggest that the previously detected increases may be due to a redistribution of channels from subcellular compartments to the plasma membrane during ischemia.

Animals↗
PubMed1994

Effect of norfloxacin and clonidine on human trabecular meshwork cells in vitro.

We evaluated the effect of norfloxacin and clonidine on the morphology, DNA synthesis and phagocytic activity of cultured human trabecular meshwork cells in the 3rd-5th generations. Exposure to norfloxacin at a concentration of 1.5 x 10(-4) g ml-1 for 6 h led to retraction of cytoplasmic processes and rounding of cell profile, and exposure for 48 h caused cell death. Exposure to clonidine at 1.0 x 10(-3) g ml-1 for 12 h caused cell degeneration, and exposure for 72 h led to cell death. The morphologic changes were dose-time dependent. Tritiated thymidine incorporation was determined as an index of DNA synthesis, which was significantly inhibited by 1.5 x 10(-5) g ml-1 norfloxacin or 1.0 x 10(-3) g ml-1 clonidine, but obviously enhanced by 1.0 x 10(-4) and 1.0 x 10(-5) g ml-1 clonidine. Both drugs inhibited phagocytosis of latex microspheres in a dose-dependent mode. According to the presented results and the pharmacokinetic data reported in the literature, we suggest that the topical use of norfloxacin should not be too frequent or continued too long, especially when the corneal epithelium was not intact; clonidine has no deleterious effect on trabecular cells in its conventional use.

Cell Death↗
PubMed1994

Clinical significance of multiple hypothalamic-pituitary functions assessment in patients with Turner's syndrome.

Hypothalamic-pituitary functions in 26 cases of Turner syndrome were assessed with a combined stimulation test. The results showed that the peak GH levels of 12 cases were less than 10 micrograms/L; 3 patients were demonstrated as having an even TSH response, while another one with a delayed TSH peak, and other 4 had high basal values and consistent exaggerated TSH responses to TRH; all patients showed increased basal and peak LH and FSH levels but 5, whose LH and FSH secretion patterns were similar to normal. 12 cases have been treated with individualized protocols and followed up for 12 months or more, of them the growth velocity all increased, especially those with hypothyroidism or with a BA less than 13. It is suggested that multiple functions of hypothalamic-pituitary axis in Turner patients be evaluated as early as possible, in order that proper treatment could be adopted and their growth and development improved.

Adolescent↗
PubMed1993

Genes in one megabase of the HLA class I region.

To define the gene content of the HLA class I region, cDNA selection was applied to three overlapping yeast artificial chromosomes (YACs) that spanned 1 megabase (Mb) of this region of the human major histocompatibility complex. These YACs extended from the region centromeric to HLA-E to the region telomeric to HLA-F. In addition to the recognized class I genes and pseudogenes and the anonymous non-class-I genes described recently by us and others, 20 additional anonymous cDNA clones were identified from this 1-Mb region. We also identified a long repetitive DNA element in the region between HLA-B and HLA-E. Homologues of this element were located at several sites in the human genome outside of the HLA complex. The portion of the HLA class I region represented by these YACs shows an average gene density as high as the class II and class III regions. Thus, the high gene density portion of the HLA complex is extended to more than 3 Mb.

Animals↗
PubMed1993

Inhibition of tumor promoter-mediated processes in mouse skin and bovine lens by caffeic acid phenethyl ester.

Caffeic acid phenethyl ester (CAPE) was isolated from propolis (a product of honeybee hives) that has been used in folk medicine as a potent antiinflammatory agent. CAPE is cytotoxic to tumor and virally transformed but not to normal cells. Our main goal was to establish whether CAPE inhibits the tumor promoter (12-O-tetradecanoylphorbol-13-acetate)-induced processes associated with carcinogenesis. Topical treatment of SENCAR mice with very low doses (0.1-6.5 nmol/topical treatment) of CAPE strongly inhibits the following 12-O-tetradecanoylphorbol-13-acetate-mediated oxidative processes that are considered essential for tumor promotion: (a) polymorphonuclear leukocyte infiltration into mouse skin and ears, as quantified by myeloperoxidase activity; (b) hydrogen peroxide (H2O2) production; and (c) formation of oxidized bases in epidermal DNA, as measured by 5-hydroxymethyluracil and 8-hydroxylguanine. A 0.5-nmol dose of CAPE suppresses the oxidative burst of human polymorphonuclear leukocytes by 50%. At higher doses (1-10 mumol), CAPE inhibits edema and ornithine decarboxylase induction in CD-1 and SENCAR mice. Interestingly, we discovered that 12-O-tetradecanoylphorbol-13-acetate-induced H2O2 production in bovine lenses also is inhibited by CAPE. Cumulatively, these findings point to CAPE as being a potent chemopreventive agent, which may be useful in combating diseases with strong inflammatory and/or oxidative stress components, i.e., various types of cancer and possibly cataract development.

Animals↗
PubMed1993

Intravitreal pharmacokinetics of liposome-encapsulated amikacin in a rabbit model.

BACKGROUND: Intravitreal injection of antibiotics has become a standard therapy for bacterial endophthalmitis. The duration of effective antimicrobial levels in the vitreous after single injection, however, may not be long enough to get optimal response. The authors prepared liposome-encapsulated amikacin for prolonging the duration of intravitreal therapeutic concentrations and investigated the intravitreal pharmacokinetics of the liposomes and amikacin in phosphate buffer solution (PBS) as control. METHODS: The liposome-encapsulated amikacin was prepared by reverse-phase evaporation method. The intravitreal pharmacokinetics of the liposomes was compared with amikacin in PBS by fluorescence polarization immunoassay. Albino rabbits were randomly distributed into 12 groups. Rabbits in groups 1 to 6 and in groups I to VI (control groups) received an intravitreal injection of the liposome-encapsulated amikacin and amikacin in PBS, respectively. RESULTS: The encapsulation rate of amikacin was 91%. The time of 50% spontaneous degradation (half-life) of the liposomes in PBS (38 degrees C, pH 7.4) was 47.6 days, and the time of 50% release (half-life) of the drug from the liposomes in PBS was 84.8 hours. The vitreous amikacin concentrations in groups 1 to 6 were significantly greater (P < 0.05) than those in control groups I to VI in every time interval, except in groups 1 to 3 at 1 hour after injection. The difference was particularly obvious in the endophthalmitis groups. The clearance of encapsulated amikacin in vitreous appeared to be related to the state of blood-ocular barrier and to the structural integrity of vitreous. The distribution, the absorption, and the elimination of encapsulated amikacin in vitreous showed the first-order kinetics. CONCLUSION: The liposome-encapsulated amikacin prolonged half-life of the drug in vitreous. The results of the pharmacokinetic analysis suggested that in endophthalmitis, especially in severe cases, the liposomes may be preferable to conventional preparation.

Absorption↗
PubMed1993

Inhibition of tumor promoter-induced hydrogen peroxide formation in vitro and in vivo by genistein.

Here we report that genistein, a soybean isoflavone, strongly inhibits tumor promoter-induced H2O2 formation both in vivo and in vitro. Genistein suppressed H2O2 production by 12-O-tetradecanoylphorbol-13-acetate- (TPA) stimulated human polymorphonuclear leukocytes (PMNs) and HL-60 cells in a dose-dependent manner over the concentration range 1-150 microM. Human PMNs were more sensitive to the inhibitory effect of genistein than HL-60 cells (50% inhibitory concentration 14.8 and 30.2 microM, respectively). In addition, genistein moderately inhibited superoxide anion formation by HL-60 cells and scavenged exogenously added H2O2 under the same conditions as in cell culture. However, the H2O2-scavenging effect of genistein was about 50% lower than its inhibition of cell-derived H2O2 formation at all concentrations. In the CD-1 mouse skin model, genistein strongly inhibited TPA-induced oxidant formation, edema, and PMN infiltration in mouse skin. Inhibition of TPA-mediated H2O2 in vivo may result from decreased cell-derived H2O2 formation, scavenging of H2O2 produced, and/or suppression of PMN infiltration into the dermis. The antioxidant properties of genistein may be responsible for its anticarcinogenic effects, and the dietary availability of genistein makes it a promising candidate for the prevention of human cancers.

Animals↗
PubMed1993

Sensitivity to tumor promotion of SENCAR and C57BL/6J mice correlates with oxidative events and DNA damage.

Significant differences in sensitivity to multistage carcinogenesis have been noted between mice that are sensitive (SENCAR) and resistant (C57BL/6J) to 12-O-tetradecanoylphorbol-13-acetate (TPA). However, the mechanism of this sensitivity has not yet been established. Recent studies from this laboratory have shown that TPA significantly enhances formation of hydrogen peroxide (H2O2) and oxidized DNA bases in SENCAR mouse skin, as it increases the infiltration of polymorphonuclear leukocytes (PMNs), as quantitated by myeloperoxidase (MPO). In the studies reported here, we compared SENCAR and C57BL/6J mice with respect to TPA-mediated edema, hyperplasia, PMN infiltration, oxidant formation and oxidative DNA damage in mouse skin. Topical application of two TPA doses (2x2-40 micrograms, 20 h apart) dose-dependently increased PMN infiltration and oxidant formation in both mouse strains, which was consistent with TPA-induced morphological alterations (edema and hyperplasia). However, at low TPA doses (2-4 micrograms), the increases over controls in the SENCAR mice were significantly greater (P < 0.01) than those in C57BL/6J mice. Comparison of the net values indicated that 4 micrograms TPA enhanced PMN infiltration (MPO units/cm2) and oxidant formation (nmol H2O2/cm2) in SENCAR mice by 7.7- and 11-fold respectively over those present in TPA-treated C57BL/6J mouse skin. At the same dose, TPA also significantly increased formation of thymidine glycol (dTG; 5.5-fold), 5-hydroxymethyl-2'-deoxyuridine (HMdU; 4.9-fold) and 8-hydroxyl-2-deoxyguanosine (8-OHdG; 11.4-fold) in SENCAR mouse epidermis. Then, the levels of all three declined. In C57BL/6J mice, there were virtually no increases at 4 micrograms TPA, but their levels gradually increased with higher TPA doses and reached maxima at 10 micrograms TPA for dTG (1.9-fold increase), at 20 micrograms TPA for 8-OHdG (6.0-fold), and at 30 micrograms TPA for HMdU (1.8-fold). We conclude that the TPA-mediated oxidative events and oxidative DNA modification by different doses of TPA correlate with the promoting potencies of those doses in both mouse strains. Therefore, they could be, at least in part, responsible for the strain-dependent sensitivity to tumor promotion.

8-Hydroxy-2'-Deoxyguanosine↗