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Biomedical subjects

Y Hui

Publications and source records attributed to Y Hui.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Observation of phagocytosis and cell junction of rabbit IPE in vitro].

PURPOSE: To study the phagocytosis and cell junctions of iris pigment epithelium(IPE) in vitro. METHODS: Chicken red blood cells were added to culture medium of IPE, the numbers of IPE phagocyting chick red blood cells were counted; cell junctions were observed with transmission electron microscope. RESULTS: The phagocytotic rates of IPE and retinal pigment epithelium (RPE) were 5.4% and 8.8% respectively; there were various tight junctions in IPE. CONCLUSION: IPE possessd phagocytosis and barrier functions in vitro.

Animals↗
PubMed2001

[Vitrectomy and photocoagulation for treatment of proliferative diabetic retinopathy].

PURPOSE: To evaluate the efficacy of vitreous surgery and photocoagulation for treatment of a series of patients with proliferative diabetic retinopathy(PDR). METHODS: A consecutive series of PDR treated with vitrectomy and photocoagulation during February 1997 to May 2000 was retrospectively analyzed. RESULTS: The series included 79 cases (38 male and 41 female) and 104 eyes [oculus dexter(OD), 26; oculus sinister(OS), 28; oculus uterque(OU), 25] with diabetic history for 0.5-37 (8.5 +/- 6.5) years and eye symptoms for 15 days to 1.5 years (1.5 +/- 1.5 years). Retinal photocoagulation was performed in 30 eyes with only once in 26 eyes before vitrectomy. Surgical techniques included standard vitrectomy, neovascular membrane peeling and fragmentation, endo--diathermy and endolaser. Silicone oil was injected in 59 eyes with active bleeding, retinal detachment, or severe ischemia. Cataract extraction was done in 63 eyes, of which 27 eyes with intraocular lens implantation. Visual acuity was light perception(LP), hand movement(HM), count fingers(CF), and > or = 0.02 in 15, 38, 22, and 29 eyes, respectively before operation. Visual improvement achieved in 84 eyes (80.8%) with > or = 0.1 in 41 eyes (39.4%). Visual acuity remained unchanged or decreased in 20 eyes (20.2%). Neovascular glaucoma occurred in two eyes after surgery. CONCLUSIONS: Although the series of patients with PDR without sufficient retinal photocoagulation before operation, vitrectomy and endolaser improved the visual outcome in the majority of eyes. Silicone oil injected in eyes with severe ischemia, active bleeding or retinal detachment may provide chance for prompt laser coagulation after surgery in order to prevent progression of PDR.

Adult↗
PubMed2001

Dexamethasone modulation on cultured human retinal pigment epithelial cell.

PURPOSE: Dexamethasone(DEX) was tested for its ability to modulate human retinal pigment epithelium(hRPE) cell proliferation in cell culture. METHODS: DEX in different concentrations was added to cultured hRPE cells. The effects were measured with MTT method, 3H-thymidine(3H-TdR) incorporation and flow cytometry. RESULTS: DEX increased survival rate and DNA synthesis from 32 mg/L to 320 mg/L under hRPE culture conditions, but paradoxically reduced them at 1,000 mg/L and 3,200 mg/L in dose and time dependent fashion by both MTT assay and 3H-TdR incorporation. The cell numbers in S phase and G2/M phase increased 28.32% at DEX concentration 320 mg/L, in contrast, reduced 41.84% at 1,000 mg/L. CONCLUSION: DEX increased proliferation from 32 mg/L to 320 mg/L, and inhibited proliferation at concentrations greater than 320 mg/L. The inhibiting effect of DEX may happen in s phase and G2/M phase.

Anti-Inflammatory Agents↗
PubMed2001

Clinical observation on preservation of lens anterior capsule in reduction of complications associated with silicone oil.

PURPOSE: To observe the effect of preservation of anterior capsule on the incidence of complications associated with silicone oil. METHODS: 82 patients (82 eyes) accepted trans pars plana vitrectomy (TPPV) combined with lensectomy of whom, 30 eyes with preservation of anterior capsule (PAC) and 52 eyes with no preservation of anterior capsule (NPAC). Analysis of the incidence of complications associated with use of oil. RESULTS: The incidence rate was 50.0% in NPAC group, and 23.3% in PAC group (P < 0.025). There were secondary glaucoma (21.1%), band keratopathy (13.5%) and corneal decompensation (9.6%) in NPAC group, while there was none of them in PAC group. CONCLUSIONS: Preservation of anterior capsule is an effective method to reduce the complications associated with silicone oil.

Adolescent↗
PubMed2001

Effect of hypericin on confocal imaging of Ca2+ signaling in cultured human retinal pigment epithelium.

PURPOSE: To investigate the mechanism of the Ca2+ signaling in cultured human retinal pigment epithelial (RPE) cells with the protein kinase C(PKC) specific inhibitor-hypericin stimulation. METHODS: Cultured human RPE cells were analyzed using the fluorescence Ca2+ dye fluo-3 AM and laser scanning confocal microscope(LSCM) after stimulation with 100 nM phorbol 12-myristate 13-acetate(PMA) and (or) 5 concentrations of hypericin(1, 2, 3, 4 and 5 microM). RESULTS: The normal fluorescence in RPE cells was strong and distributed throughout the cells. The nucleus appeared to be more fluorescent than the cytoplasm. After stimulation with PMA alone or 5 concentrations of hypericin, a rapid decrease in flurescence intensity was observed. There was no obvious difference in decreased curve among 5 concentrations. However, after stimulation with a 24 hr preincubation of PMA and 5 concentrations of hypericin, a further decrease was not observed. CONCLUSION: Fluo-3 AM appears to be a good indicator of the change in Ca2+ occurring in RPE cells and hypericin is a strong inhibitor of Ca2+ influx channel. Hypericin has potential as a therapeutic drug for proliferative vitreoretinopathy(PVR), the inhibitory effect on PVR might be caused by blocking the PKC activity and inhibiting Ca2+ influx pathway.

Adult↗
PubMed2001

[Character of alpha-crystallin molecular chaperone activity in selenite cataract].

PURPOSE: To evaluate the character of alpha-crystallin molecular chaperone activity in selenite cataract. METHODS: alpha-Crystallin from lenses of normal young rats and lenses with selenite cataract were separated and purified by gel filtration chromatography. The chaperone activity of alpha-crystallin was assayed by mearsuring heat-induced aggregation and scattering of catalase. RESULTS: alpha-Crystallin in both normal and cataractous lenses specifically prevented catalase against thermal aggregation compared with control proteins. The preventive ability in alpha H-crystallin was less than in alpha L-crystallin. Chaperone activity was diminished in selenite cataract. There was statistically significant difference in chaperone activity between normal and cataractous lenses in both alpha H-crystallin and alpha L-crystallin respectively. CONCLUSION: The reduction of alpha-crystallin chaperone activity in selenite cataract by preventing thermal aggregation of catalase is an important process in cataract formation.

Animals↗
PubMed2001

[Speech discrimination with bilateral cochlear implants in noisy conditions].

OBJECTIVE: To investigate the speech discrimination abilities of patients with bilateral cochlear implants. METHODS: The speech discrimination scores of Cantonese lexical tones were compared between two patients with unilateral and bilateral cochlear implants at different signal to noise (S/N) ratios. RESULTS: At favorable listening conditions with S/N ratios of +15, +10, and the mean binaural speech discrimination scores were 96%, 92% and 88%, but the mean monaural speech discrimination scores from the left and right ear were 86%, 83% and 74% respectively. At unfavorable listening conditions with adverse S/N ratios of 0, -5, -10 and -15, almost no speech discrimination scores could be obtained from monaural hearing but 80%, 72%, 68% and 54% respectively from binaural stimulation. CONCLUSION: Bilateral cochlear implants improve the discrimination of Cantonese lexical tones better than unilateral cochlear implant at various S/N ratios This study confirms the benefits of binaural hearing even in patients using bilateral cochlear implants.

Adult↗
PubMed2000

A novel and effective procedure for the preparation of glucuronides.

6-Phenylthio-6-deoxy-D-glucopyranosides were easily prepared from 6-hydroxy-D-glucopyranosides and employed as effective glycosyl donors or acceptors. And the resulting coupling products were then readily converted into the corresponding D-glucuronide-containing compounds.

Carbohydrate Conformation↗
PubMed2000

Chinese tonal language rehabilitation following cochlear implantation in children.

Cantonese language rehabilitation in 28 prelingually deaf children who underwent cochlear implantation was evaluated. All patients were implanted with multichannel devices and the operations went smoothly. They all had improved scores on audiological assessments and speech perception tests. The speech evaluation tests included the recognition of sounds, vowels, consonants and tone. Sentence recognition and story comprehension were both improved after training for 2 years. Cochlear implantation is a useful measure for the speech rehabilitation of prelingually profound deaf children when hearing aids are of no benefit. The multichannel implant device is of clinical significance in the rehabilitation of those patients using tonal language.

Child↗
PubMed2000

Risk factors for active liver disease in HBeAg-negative chronic hepatitis B virus-infected patients.

OBJECTIVES: HBeAg-negative patients constitute approximately 70% of all chronic hepatitis B virus (HBV) infections in Southeast Asia, and some of these patients continue to suffer from active disease. We aimed to study the risk of hepatitis relapse in chronic HBV-infected patients with negative HBeAg and the predictor(s) of relapses. METHODS: This was a retrospective analysis of patients carrying HBsAg but lacking HBeAg. Patients recruited were required to have been followed for > or = 12 months with a minimum of three blood samples available for analysis. Patient demographic data, liver biochemistry, and HBV serology were analyzed in relation to relapses of hepatitis. Relapse was defined as an abrupt elevation of ALT > 200 IU/L or > 3-fold previous levels, whichever was higher. RESULTS: In a period of 3 months, 317 patients seen at the Hepatitis Clinic at the Prince of Wales Hospital in Hong Kong were recruited. The median duration of follow-up was 34 months. On initial consultation, 111 (35.0%) patients had elevated ALT (>60 IU/L). Overall, 57 (18.0%) patients developed at least one relapse, including 37 (33.3%) patients with elevated ALT and 20 (9.7%) patients with normal ALT at the first visit. Multiple logistic regression analysis showed that elevated ALT level at first presentation (odds ratio 4.17, 95% confidence interval 2.24-7.75) and male gender (odds ratio 2.83, 95% confidence interval 1.23-6.49) were the two independent factors associated with a higher risk of hepatitis relapse. The sensitivity, specificity, and positive and negative predictive values of a single ALT test for hepatitis relapse were 64.9%, 71.5%, 33.3%, and 90.3%, respectively. CONCLUSIONS: HBeAg-negative HBV carriers with normal ALT levels have a low risk of hepatitis relapse.

Adult↗
PubMed2000

Correlation of pure tone audiogram results and hearing benefit of tympanoplasty for chronic suppurative otitis media.

The aim of this study was to evaluate the correlation between pure tone audiogram results and the subjective sensation of hearing benefit of patients who had tympanoplasty for chronic suppurative otitis media. This is a prospective study of 115 patients who had tympanoplasty between 1992 and 1994. The outcome, including a pure tone audiogram and the subjective sensation of hearing benefit, was evaluated at 1 year after operation. There were 63 (55%) patients with subjective hearing benefit after the tympanoplasty. The subjective sensation of hearing benefit correlated with the magnitude of the air conduction (AC) threshold reduction, and increased from 39% for an AC reduction of less than or equal to 10 dB to 100% for an AC reduction of more than 30 dB. The effect of the interaural AC threshold difference on the subjective sensation of hearing was not significant; improvement was felt by 92% of patients when the operated ear became the better hearing ear, and by 73% of patients when the operated ear remained the worse hearing ear. There was considerable discrepancy between the subjective hearing benefit and the pure tone audiogram results. A combination of parameters, including the air-bone gap, the AC threshold, and the subjective hearing change, is recommended in reporting the results of tympanoplasty.

Audiometry, Pure-Tone↗
PubMed2000

Degradation of the photosystem I complex during photoinhibition.

Exposure of isolated photosystem I (PSI) complexes to illumination (2300 microE m(-2) s(-1)) for various periods of time resulted in striking changes in their absorption spectra. A 6 nm blueshift of the absorption maximum in the red was detected after 100 min illumination. The fourth derivative of the absorption spectra verifies that the main change of the red peak was attributed to the 682 nm absorption band. Further, it was also shown that a shoulder in the absorption spectra located around 470 nm decreased after the first 5 min of illumination and almost disappeared after 40 min illumination, suggesting that chlorophyll b bound to light-harvesting complex I (LHCI) is also sensitive to excess light. A maximum inhibitory effect on the oxygen uptake rates and a strong stimulation were observed when the PSI complexes were exposed to illumination for about 20 and 40 min, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows that LHCI-680 started to degrade during the first 5 min of illumination and almost completely disappeared after 40 min of illumination. These observations demonstrated that LHCI was more sensitive to illumination than the PsaA/B subunits which also presented some degradation signs after 40 min illumination. In addition, insoluble-cohesive-denatured proteins also appeared between the stacking and resolving gel after prolonged illumination (100 min). A photoprotective function of LHCI for the PSI reaction center is proposed.

Light↗
PubMed2000

Epidemiology of human geohelminth infections (ascariasis, trichuriasis and necatoriasis) in Lushui and Puer Counties, Yunnan Province, China.

Between April and June of 1998, the prevalence and intensity of geohelminth infections caused by hookworm, Ascaris and Trichuris were investigated in two rural Yunnan villages. In Liuku, a village of Lisu indigenous people in Lushui County, there was an overall geohelminth prevalence of 72% (48%, 43% and 16% for hookworm infection, ascariasis, and trichuriasis, respectively). The prevalence of ascariasis was greatest among preschool and school aged children, whereas the prevalence of trichuriasis was greatest among teenagers and the prevalence of hookworm increased until the age of 10-15 and then remained high throughout adulthood. In Linger, a village of Han Chinese, located in Puer County, there was an overall geohelminth prevalence of 77% (30%, 60% and 36% for hookworm infection, ascariasis, and trichuriasis, respectively). The differences in prevalence for hookworm and ascariasis were statistically significant. The prevalence of hookworm in Linger increased steadily with age and did not plateau, but there were no discernible patterns of prevalence versus age for either ascariasis or trichuriasis. Heavy trichuriasis infections were noted to occur in Linger. In both villages, more than 98% of the hookworm infections were of light and moderate intensity. Both by morphologic identification of third-stage infective larvae (L3) from eggs as well as identification of adult hookworms recovered from adult residents after treatment with quantrel, Necator americanus was identified as the exclusive hookworm in each village. Geohelminth infections caused by Ascaris, Trichuris and hookworm remain highly endemic to the rural areas of Yunnan Province in southwestern China.

Adolescent↗