Biomedical subjects

H Wei

Publications and source records attributed to H Wei.

At least 145 records · Page 8Linked to original sources

PubMed1998

[Analysis of blood flow in ophthalmic arteries in patients with middle and late stages of glaucoma with Doppler sonography].

OBJECTIVE: To understand the actual blood flow in cases with middle and late stages of glaucoma and the role of vascular factor in the deterioration of visual function in such patients. METHODS: The blood flow in ophthalmic arteries was determined with color Doppler sonography (CDS) in 156 cases of patients with middle and late stages of glaucoma as well as in 75 cases of normal individuals as controls. RESULTS: The average peak systolic velocity (PSV) and end diastolic velocity (EDV) of ophthalmic artery in normal control are 35.98 +/- 9.13 cm/s and 11.98 +/- 3.90 cm/s; the PSV and EDV in primary open-angle glaucoma (POAG) group are 24.13 +/- 4.65 cm/s and 7.10 +/- 1.85 cm/s; and in primary close-angle glaucoma (PCAG) group are 22.89 +/- 5.43 cm/s and 7.06 +/- 1.92 cm/s, respectively. No significant difference was found between POAG group and PCAG group (P > 0.05). However, significant differences were shown between normal group and patients with glaucoma for both PSV and EDV (P < 0.01). CONCLUSION: The blood flow in ophthalmic arteries in patients with middle and late stages of glaucoma decreases significantly and the disorder in local blood circulation is evident, that is highly related to the deterioration of visual function and supports the vascular factor theory in the pathogenesis of glaucoma.

Adult↗

PubMed1998

[The influence of pressure on human lamina cribrosa cell and its collagen synthesis].

OBJECTIVE: To study the influence of pressure on human lamina cribrosa cell (HLC) and its synthesis of collagen. METHOD: HLCs were cultured in vitro and submitted to elevated hydrostatic pressure, their changes in morphology were observed by light and electron microscopy and their synthesis of collagen was measured with fluorescence spectrophotometer. RESULTS: Under a hydrostatic pressure of 6.67 kPa (1 kPa = 7.5 mmHg), the flat and polygonal HLCs became elongated. Vacuoles appeared in the cytoplasm and increased as the pressure persisted. The mitochondria were swollen, some of them turned into vacuoles, and myelin figures were found in the cytoplasm. When exposed to elevated pressure for 3 days, the amounts of synthesized collagen type I, III, IV were 43.95 +/- 6.37, 61.35 +/- 10.35 and 82.90 +/- 11.36 arbitrary unit (AU) by fluorometry respectively, and compared to controls, they were statistically significantly (P < 0.05) increased; after 5 days of pressure exposure, the amounts were 33.50 +/- 6.94, 40.85 +/- 12.30 and 80.45 +/- 14.65 AU, e.g., still increased. CONCLUSION: It is indicated that under pressure, HLCs undergo obvious morphological changes and increase their synthesis of collagen types I, III and IV.

Collagen↗

PubMed1998

[A clinical observation of the therapeutic effects of pilocarpine gel for treatment of glaucoma].

OBJECTIVE: To evaluate whether pilocarpine gel (PG) is better than pilocarpine solution (PS) for treatment of glaucoma. METHODS: 20 cases with glaucoma treated with 4% PG once every night were compared with 20 cases with glaucoma using 1% PS 4 times a day. The intraocular pressure (IOP), pupil diameter and refraction were examined 4 times a day in both groups. RESULTS: The PG could lower IOP by 25% - 37% and the PS by 20% - 25%, the hypotensive effect of PG could last 24 hours. The PG had the strongest hypotensive effect 5 - 13 hours after its application, and a stronger action than PS at 9 a.m. and 11 a.m, this is particularly beneficial for the control of the peak IOP before awaking and in the morning. The strongest action of miosis and accommodation enhancement of PG took place 5 - 8 hours after its application when the patients were sleeping, whereas the PS induced a fluctuating miosis and myopia in the day time. In addition, the PG was more convenient to be used than PS due to its single application for 24 hours. CONCLUSION: The PG has some advantages in the respects of compliance, lowering IOP and side-effects, thus it is worthwhile to promote its manufacture.

Adult↗

PubMed1998

[The effect of elevated hydrostatic pressure on expression level of type III collagen mRNA by lamina cribrosa cells in vitro].

OBJECTIVE: To investigate the effect of elevated hydrostatic pressure on the expression level of type III collagen mRNA by lamina cribrosa cells (LCCs) and approach the action of changes of extracellular stroma on glaucomatous optic nerve damage. METHODS: LCCs were cultured and submitted to elevated hydrostatic pressure (4.67 - 5.33 kPa). We observed collagen type III mRNA level by dot-blot hybridization and computer imaging analysis. RESULTS: Under the pressure for 3 days, the amounts of collagen III mRNA were 0.5828 +/- 0.0517 in optical density (OD), compared with the same period controls (0.2832 +/- 0.0613), the difference was statistically significant (P < 0.05). When exposed to pressure up to 6 days, the collagen III mRNA level remained somewhat higher than that of the control, but there was no significant difference (P > 0.05). After 9 to 12 days of exposure to pressure, the mRNA amounts were decreased respectively to 0.3246 +/- 0.0957 and 0.2164 +/- 0.0171 in OD that were lower than that of the control in the respective same periods, and the differences between the experimental and the control had no significance (P > 0.05). CONCLUSION: Elevated hydrostatic pressure may increase expression level of collagen III mRNA by LCCs in a certain period.

Collagen Type III↗

PubMed1998

[Biochemical analysis of proteoglycan in bovine trabecular meshwork and its significance].

OBJECTIVE: To determine the kinds of proteoglycan (PG) monochain and their distribution in the cell layer and cultural medium of bovine trabecular meshwork (BTM) culture. METHODS: (3)H-glycosamine was incorporated in BTM cells in the third passage. PGs were extracted by 4 mol/L guanidine hydrochloride. The aliquots were chromatographed on Sephadex G-50 DEAE-Sephacel, Sepharose 4B and Sepharose CL-6B gel respectively. Glycosaminoglycan was obtained by basic hydrolysis and enzyme degradation, and scintillation counting was used for the assay of radioactivity. RESULTS: Four different PGs were analyzed. The composition of PGs in cell layer was hyaluronic acid PG 30.2%, heparin sulfate PG 20.9%, chondroitin sulfate PG 21.6%, dermatan sulfate PG 18.1% and others 9.2%, while in the medium was 24.2%, 20.1%, 25.7%, 23% and 7%, respectively. CONCLUSIONS: PGs are confirmed to be present in the extracellular matrix of BTM cells in vitro. BTM cells also have the ability to secrete these macromolecules into the medium. Abnormal synthesis, secretion, accumulation and changes of PG pattern in physiologic conditions and under any drugs may contribute to the pathogenesis and treatment of primary open-angle glaucoma.

Animals↗

PubMed1998

[Studies on chemical constituents from the root of Coriaria nepalensis wall (Coriaria sinica Maxim)].

The root of Coriaria nepalensis Wall (Coriaria sinica Maxim) is a Chinese herbal medicine and has been used to treat numbness, toothache due to wind and heat, phlegm-retention syndrome, traumatic injury and acute conjunctivitis. Nine compounds were isolated from the root of Coriaria nepalensis Wall and they were identified as braylin (I), norbraylin (II), dihydrocoriamyrtin (III), coriamyrtin (IV), tutin (V), coriatin (VI), apotutin (VII), hydroxycoriatin (VIII) and gallic acid (IX) on the basis of their physicochemical properties and IR, UV, MS, 1HNMR, 13CNMR data. I, II were isolated from the title plant for the first time; III was obtained from plant origin for the first time, and VII, VIII were new compounds.

Lactones↗

PubMed1998

An analysis of 1,001 blinding patients with corneal disease in 1960-1989.

PURPOSE: To investigate the condition and change of corneal blindness (CB) in the past 30 years. METHODS: 1,001 blinding patients of corneal disease were clinically analysed from 1960 to 1989, including etiology, sex, age, occupation, difference between the urban and rural areas etc. RESULTS: The male predominated. Infection stood the first cause of blinding corneal diseases, followed by trauma, malnutrition and the others. HSV-1 keratitis was the most frequent infection in 1980s. The highest incidence of CB was 20-40 year-old. The number of CB caused by occupational trauma was more than that by ordinary trauma in 1960s, but from 1970s, the latter was more than the former. The number of CB in rural area was more than that in the urban in 1960s, but from 1970s, there was no significant difference between the two areas. The percentage of bilateral CB was gradually decreased. CONCLUSION: We should try to find more effective strategies to prevent and treat CB caused by HSV-1 keratitis, pay special attention to preschool blindness caused by perforation injuries and avoid infection after corneal injuries of foreign bodies.

Adolescent↗

PubMed1997

Glial cell line-derived neurotrophic factor-dependent RET activation can be mediated by two different cell-surface accessory proteins.

Glial cell line-derived neurotrophic factor (GDNF)-dependent activation of the tyrosine kinase receptor RET is necessary for kidney and enteric neuron development, and mutations in RET are associated with human diseases. Activation of RET by GDNF has been shown to require an accessory component, GDNFR-alpha (RETL1). We report the isolation and characterization of rat and human cDNAs for a novel cell-surface associated accessory protein, RETL2, that shares 49% identity with RETL1. Both RETL1 and RETL2 can mediate GDNF dependent phosphorylation of RET, but they exhibit different patterns of expression in fetal and adult tissues. The most striking differences in expression observed were in the adult central and peripheral nervous systems. In addition, the mechanisms by which the two accessory proteins facilitate the activation of RET by GDNF are quite distinct. In vitro binding experiments with soluble forms of RET, RETL1 and RETL2 demonstrate that while RETL1 binds GDNF tightly to form a membrane-associated complex which can then interact with RET, RETL2 only forms a high affinity complex with GDNF in the presence of RET. This strong RET dependence of the binding of RETL2 to GDNF was confirmed by FACS analysis on RETL1 and RETL2 expressing cells. Together with the recent discovery of a GDNF related protein, neurturin, these data raise the possibility that RETL1 and RETL2 have distinctive roles during development and in the nervous system of the adult. RETL1 and RETL2 represent new candidate susceptibility genes and/or modifier loci for RET-associated diseases.

Amino Acid Sequence↗

PubMed1997

Detection of underivatized carbohydrates in capillary electrophoresis with a bienzyme electrode.

A new approach to detect underivatized carbohydrates in capillary zone electrophoresis (CZE) with a bienzyme electrode is described. The bienzyme electrode is based on immobilization of two enzymes, glucose oxidase and amyloglucosidase, on a platinum microelectrode. Maltose and glucose were used as substrates to establish the method and study its feasibility. Using this electrode, underivatized glucose and maltose were determined after separation in 60 mM borate buffer (pH 9.3) by CZE. A liquid junction, between the surface of the bienzyme electrode and the outlet of the separation capillary, was used to lower the pH of the eluting separation borate buffer so that the immobilized enzymes could maintain high activities. The detection limits were 0.17 mM for maltose and 0.35 mM for glucose. The effects of borate ion and pH on the responses of the bienzyme electrode to maltose and glucose are discussed. The bienzyme electrode did not show any decay in responses to maltose or glucose during one week of continuous operation.

Biosensing Techniques↗

PubMed1997

Detection of 13C-labeled metabolites in the in vivo canine heart by B1 insensitive heteronuclear coherent polarization transfer and comparison of signal enhancement with NOE.

A recently developed adiabatic coherent polarization transfer enhancement technique [H. Merkle, H. Wei, M. Garwood, K. Uğurbil. J. Magn. Reson, 99, 480-494 (1992)] was employed to perform 13C spectroscopy in the intact canine heart in vivo during [2-13C]-acetate infusion into the left descending coronary artery, the results were compared with 13C spectra obtained with conventionally employed nuclear Overhauser enhancement. The results demonstrate that both methods can be performed by using surface coils to obtain in vivo 13C spectra and that coherent polarization transfer provides better enhancement than NOE for [2-13C]-acetate but not for short T2 compounds.

Acetates↗

PubMed1997

Singlet oxygen involvement in ultraviolet (254 nm) radiation-induced formation of 8-hydroxy-deoxyguanosine in DNA.

In the present article, we report that ultraviolet (UV 254 nm) radiation substantially induced the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in purified DNA. The formation of 8-OHdG, a hallmarker of oxidative DNA damage, increased linearly up to 25 kJ/m2 and was dependent on the presence of oxygen in the solution. Deoxygenation by nitrogen significantly reduced the yield of 8-OHdG by UV radiation, whereas oxygenation with 100% oxygen substantially enhanced the yield. The hydroxyl radical (HO.) scavenger dimethysulfoxide (DMSO) dramatically quenched the formation of 8-OHdG by the ionizing radiation and Fenton reaction, but enhanced the formation of UV-induced 8-OHdG. Further studies showed that DMSO and mannitol, two predominant HO. scavengers, enhanced the levels of UV-induced 8-OHdG in a dose-dependent fashion, suggesting that UV-induced 8-OHdG is independent of the generation of HO.. The use of deuterium oxide (D2O), which prolongs the half life of singlet oxygen (1O2), substantially enhanced the yield of 8-OHdG by UV radiation, but not that by Fenton reaction. In contrast, sodium azide, a more and less specific 1O2 quencher, substantially reduced the levels of 8-OHdG by both UV radiation and Fenton reaction, indicating that sodium azide lacks the quenching specificity of 1O2 and HO.. It is proposed that UV induced 8-OHdG proceeds through a singlet oxygen involvement mechanism, rather than the generation of hydroxyl radicals.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1997

Identification of possible reactive oxygen species involved in ultraviolet radiation-induced oxidative DNA damage.

We have previously demonstrated that each region of the ultraviolet (UV) spectrum (UVA, UVB, and UVC) induces the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) in purified calf thymus DNA and HeLa cells in a fluence-dependent manner. In the present study, we further characterize the possible reactive oxygen species (ROS) that are involved in the induction of 8-oxodGuo by UV radiation. Sodium azide, a singlet oxygen (1O2) scavenger though its quenching effect on HO. was also reported, inhibited 8-oxodGuo production in calf thymus DNA exposed to UVA, UVB, or UVC in a concentration-dependent fashion with maximal quenching effect of over 90% at a concentration of 10 mM. Catalase, at a concentration of 50 U/ml, reduced the yields of UVA- and UVB-induced 8-oxodGuo formation by approximately 50%, but had little effect on UVC-induced 8-oxodGuo production. In contrast, 50 U/ml of superoxide dismutase (SOD) did not affect induction of 8-oxodGuo by any portion of the UV spectrum. Hydroxyl radical (HO.) scavengers mannitol and dimethylsulfoxide (DMSO) moderately reduced the levels of 8-oxodGuo induced by UVA and UVB, but not those by UVC. Instead, mannitol and DMSO enhanced the formation of 8-oxodGuo induced by UVC. These results suggest that certain types of ROS are involved in UV-induced 8-oxodGuo formation with 1O2 playing the predominant role throughout the UV spectrum. Except for UVC, other ROS such as hydrogen peroxide (H2O2) and HO. may also be involved in UVA- and UVB-induced oxidative DNA damage. Superoxide anion appears not to participate in UV-induced oxidation of guanosine in calf thymus DNA, as SOD did not display any quenching effects.

Catalase↗

PubMed1997

Effect of structurally related flavones/isoflavones on hydrogen peroxide production and oxidative DNA damage in phorbol ester-stimulated HL-60 cells.

We have examined the antioxidant properties of structurally related flavones/isoflavones in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated HL-60 cells. In the presence of 1.3% dimethyl sulfoxide in the medium for seven days, promyelocytic HL-60 cells were differentiated into neutrophil-like cells possessing phagocytic properties and the capacity to generate H2O2 on TPA stimulation. The effects of five selected flavones/isoflavones on the formation of H2O2 and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were examined in TPA-stimulated HL-60 cells. The results indicated that genistein was the most potent inhibitor of H2O2 production by TPA-stimulated HL-60 cells, followed by apigenin and daidzein, whereas prunectin and biochanin A exhibited no effect. This inhibitory effect correlates well with the scavenging capacity of H2O2 by these flavones/isoflavones in an in vitro system. The formation of 8-OHdG in cellular DNA of HL-60 cells was induced by TPA and further enhanced by the addition of FeCl2 to the medium. Most flavones/isoflavones significantly inhibited TPA + FeCl2-induced 8-OHdG formation in HL-60 cells, with genistein being the most potent quencher. The inhibition of H2O2 production and 8-OHdG formation by these structurally related flavones/isoflavones may contribute to their chemopreventive potentials against human cancers.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1997

Peripherally administered alpha2-adrenoceptor agonist in the modulation of chronic allodynia induced by spinal nerve ligation in the rat.

UNLABELLED: We studied whether a peripherally administered alpha2-adrenoceptor agonist modulates mechanical allodynia caused by unilateral ligation of two spinal nerves in the rat. Medetomidine, an alpha2-adrenoceptor agonist, atipamezole, an alpha2-adrenoceptor antagonist, or saline (control) was administered into the footpad of either the allodynic or the contralateral hindpaw. Medetomidine (1-10 microg/kg in 50 microL) reversed the unilateral allodynia in a dose-dependent fashion independent of the site of administration. At this dose range, medetomidine did not influence the heat-induced tail-flick response. The antiallodynic effect of medetomidine was completely reversed by a dose of atipamezole that alone was ineffective (30 microg/kg). At the largest dose used (100 microg/kg in 50 microL), atipamezole decreased the latency of the heat-induced tail flick and had an ipsilateral allodynic effect in the injected paw when administered into the control side. The atipamezole-induced mechanical allodynia was not attenuated by medetomidine. The results indicate that an alpha2-adrenoceptor agonist at a subantinociceptive dose may significantly attenuate allodynia produced by spinal nerve ligation. This antiallodynic effect is not due to a peripheral action, but rather to action on central (presumably spinal) alpha2-adrenoceptors. The allodynic effect of a high concentration of atipamezole (100 microg/kg in 50 microL) in the injected paw can be explained by peripheral nonadrenergic mechanisms (e.g., local irritation). IMPLICATIONS: The present behavioral results indicate that a selective alpha2-adrenoceptor agonist at a subantinociceptive dose effectively attenuates mechanical allodynia induced by an experimental model of chronic neuropathy in the rat. This antiallodynic action can be explained by central, rather than peripheral, alpha2-adrenergic mechanisms.

Adrenergic alpha-2 Receptor Agonists↗

PubMed1997

Induction of 8-oxo-7,8-dihydro-2'-deoxyguanosine by ultraviolet radiation in calf thymus DNA and HeLa cells.

The levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) in purified calf thymus DNA and HeLa cells were measured following exposure to either UVC, UVB or UVA wavelengths. This DNA damage was quantitated using HPLC coupled with an electrochemical detector. The 8-oxodGuo was induced in purified DNA in a linear dose-dependent fashion by each portion of the UV spectrum at yields of 100, 0.46 and 0.16 8-oxodGuo per 10(5) 2'-deoxyguanosine (dGuo) per kJ/m2 for UVC, UVB and UVA, respectively. However, the amount of 8-oxodGuo in HeLa cells irradiated with these UV sources decreased to approximately 2.0, 0.013 and 0.0034 8-oxodGuo per 10(5) dGuo per kJ/m2, respectively. In contrast, the levels of cyclobutyl pyrimidine dimers were similar in both irradiated DNA and cells. Therefore, 8-oxodGuo is induced in cells exposed to wavelengths throughout the UV spectrum although it appears that protective precesses exist within cells that reduce the UV-induced formation of this oxidative DNA damage. Cell survival was also measured and the number of dimers or 8-oxodGuo per genome per lethal event determined. These calculations are consistent with the conclusion that dimers play a major role in cell lethality for UVC- or UVB-irradiated cells but only a minor role in cells exposed to UVA wavelengths. In addition, it was found that the relative yield of 8-oxodGuo to dimers increased nearly 1000-fold in both UVA-irradiated cells and DNA compared with cells subjected to either UVC or UVB. These results are supportive of the hypothesis that 8-oxodGuo, and possible other forms of oxidative damage, play an important role in the induction of biological effects caused by wavelengths in the UVA portion of the solar spectrum.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1997

[Expression of messenger RNA for transforming growth factor-beta 1 in bovine trabecular meshwork].

OBJECTIVE: To investigate the relationship between transforming growth factor-beta 1 (TGF-beta 1) and primary open-angle glaucoma. METHODS: Total RNA of 24 new born bovine trabecular tissue was extracted by guanidine isothiocyanate method. The TGF-beta 33 plasmid was brought into colibacillus HB101 and amplified. After Bam HI enzyme degradation and label with alpha-32P-dATP, the RNA was hybridized with the complementary DNA (cDNA) probe and examined by autoradiography to determine the expression of messenger RNA (mRNA) for TGF-beta 1. RESULTS: The presence of mRNA for TGF-beta 1 in bovine trabecular meshwork was confirmed. CONCLUSION: The TGF-beta 1 present in normal aqueous humor at least partly is derived from the trabecular meshwork. The result offers a basis for understanding the relationship between abnormal synthesis, activation and clearance of TGF-beta 1 and the pathogenesis of primary open-angle glaucoma in molecular biology.

Animals↗

PubMed1997

[Cell culture of human lamina cribrosa in vitro].

OBJECTIVE: To investigate the physiology and pathology of the biosynthesis of extracellular matrix (ECM) by lamina cribrosa cells (LCC) and to establish a model of cultured LCC. METHODS: The LCC of 10 human dead fetal eyes were cultured with enzyme digestion procedures in vitro. The cultured cells were identified by immunohistochemistry assays and electron microscopy. RESULTS: The cultured cells were flat, polygonal in shape, and their cytoplasm contained abundant perinuclear granules. The nuclei were relatively transparent and nucleoli were clear, there were basement membrane-like material and ECM surrounding the cell membrane. The immunofluorescent staining was positive for collagen type I, III, IV, fibronectin and laminin, negative for glial fibrillar acid protein and factor-VIII. The characteristics mentioned above were coincident with the morphology of LCC. This cell line has been cultured to its fourth generation. CONCLUSION: We have successfully cultured a cell line of LCC, and it may be utilized in the study of pathogenesis of glaucoma.

Cells, Cultured↗

PubMed1997

[The cloning, expression, purification and bioactivity identification of recombinant IGF-I].

The fragment containing IGF-I cDNA and cyc1 terminator from PSK-IGF-I plasmid was cloned into PSK43 SB treated by Hind III, Klenow and Cla I, generating a recombinant PSB-IGF-I (DH), which have double Hind III sites. This plasmid was treated by Hind III and Klenow, ligated to give a recombinant plasmid PSB-IGF-I(NH), which has no Hind III site. After analysed by restriction endonucleases and sequencing, the fusion site was verified to be correct. This plasmid was excised and a BamH I-Cla I fragment containing yeast alpha-factor promotor, leader sequence, IGF-I cDNA and cycl terminator was cloned into yeast episomal plasmid vector YEpHC8, generating a recombinant plasmid YEpHC8-IGF-I. Transformed this plasmid into yeast competence cells BJ1990 by using LiAc method. The expressed products were secrected into the medium broth and having the correct molecular weight of 8,100 on SDS-PAGE. The products of IGF-I were raised by using high-cell-density fermentation of Saccharomyces cerevisiae. The cleared supernatant of yeast medium was applied to Bio-Rex 70 resin, eluted with 1 mol/L ammonium acetate, pH8.0. Main peak was pooled and applied to Bio-Gel P10 (200-400 mesh). The second peak was collected and get relatively pure IGF-I proteins. The biological activities of IGF I product was assayed in NIH3T3 cells by using MTT method. The results show that the expressed IGF-I can obviously stimulate NIH3T3 cells to proliferate at the concentration ranging from 10 ng/ml to 50 ng/ml, suggesting that the protein has its biological activities.

3T3 Cells↗