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Biomedical subjects

Y H Kuo

Publications and source records attributed to Y H Kuo.

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

Progression of hydroxychloroquine retinopathy after discontinuation of therapy: case report.

Chloroquine and its derivative, hydroxychloroquine sulfate, have been used in treating malaria, dermatitides of systemic lupus erythematosus and rheumatoid arthritis. Hydroxychloroquine retinopathy is uncommon in Taiwan. Here we report a patient with hydroxychloroquine retinopathy which progressed even after discontinuation of hydroxychloroquine. A 42-year-old woman had systemic lupus erythematosus for twenty years. She had been treated with 200 to 400 mg of hydroxychloroquine per day (4 to 8 mg/kg of body weight/day) with a cumulative dose of 657 g. After bull's-eye maculopathy was found, hydroxychloroquine was discontinued. Her medical history revealed no chloroquine administration and no other systemic disease. Five years after cessation of the therapy, her visual acuity and visual fields continued to deteriorate. Ophthalmoscopic examination revealed the hydroxychloroquine retinopathy had advanced. To the best of our knowledge, the progression of hydroxychloroquine retinopathy after discontinuation of medications is a rare phenomenon. Regular ophthalmologic examinations should be performed for patients on hydroxychloroquine regimens because there is no satisfactory treatment for hydroxychloroquine retinal toxicity. Ophthalmologists, dermatologists and rheumatologists should monitor for ocular toxicity of hydroxychloroquine carefully.

Adult↗
PubMed2000

Synthesis of 60- and 72 kDa heat shock proteins in early porcine embryogenesis.

Proteins of selected embryonic stages were metabolically labeled with [(35)S]-methionine and analyzed by two-dimensional SDS-polyacrylamide gel electrophoresis (2-D PAGE) to study protein expression from 4- to 8-cell to blastocyst stage of porcine embryos. Two proteins with molecular weights of 60 and 72kDa were de novo synthesized during the 4- to 8-cell stage were the earliest that were detected. They were identified as HSP60 and HSP72 according to their locations on 2-D autoradiography and the immunoblotting result of anti-HSP 60 and HSP 72 antibodies of 1-cell stage of porcine embryos. In protein translation in early pig embryogenesis the timing of their synthesis suggests that HSP60 and HSP72 play significant roles as chaperones.

Animals↗
PubMed2000

Association of heat shock protein 70 with semen quality in boars.

This study attempted to clarify the relationship between the levels of 70kDa heat shock protein (HSP70) and semen quality in boars. Semen samples from 29 (13 Duroc, 9 Landrace, and 7 Yorkshire) boars (mean age=25.2+/-2.2 months) were examined. Three to four ejaculates per boar, collected during cool and hot seasons, were evaluated in terms of the sperm concentration, sperm motility, percentage of normal and abnormal sperm, as well as percentage of sperm with proximal and distal plasma droplets. Significant seasonal and breed differences in semen quality were observed. Experimental results indicate that the semen quality of Landrace boars was better than those of Yorkshire and Duroc boars (P<0.05) and semen quality declined significantly during the hot season (P<0.05). One-dimensional SDS-PAGE analysis of spermatozoa proteins indicated that protein profiles did not significantly differ between seasons and among breeds. Both constitutive and stress-inducible form of HSP70 were detected in boar spermatozoa by Western blot analysis. The level of HSP70, which revealed no difference among breeds within a season, was significantly lower during the hot season in all the three breeds (P<0.05). Although there appeared to be low correlation coefficients between the level of HSP70 and semen quality traits, the semen quality tended to decline significantly in samples with a lower level of HSP70. Results in this study suggest that the levels of HSP70 in boar spermatozoa are significantly lower during the hot season and might be associated with semen quality.

Animals↗
PubMed2000

Selection of drug-resistant variants in the female genital tract of human immunodeficiency virus type 1-infected women receiving antiretroviral therapy.

We investigated human immunodeficiency virus (HIV) type 1 RNA, proviral DNA, and antiretroviral drug-resistant variants in cervicovaginal secretions of HIV-1-infected women receiving antiretroviral therapy. The prevalence of detectable HIV-1 RNA in genital secretions was inversely related to the number of antiretroviral drugs taken by the patients. Proviral DNA was detected in approximately half of all samples of cervicovaginal secretions from HIV-1-infected women, regardless of the presence or absence of HIV-1 RNA in cervicovaginal secretions and of the antiretroviral regimen. In cervicovaginal secretions of most women with persisting genital viral replication, HIV variants exhibiting mutations associated with drug resistance against protease and reverse-transcriptase pol genes were found. Our observations indicate that antiretroviral therapy is not effective in purging the female genital tract of cell-associated provirus and that antiretroviral drugs that penetrate the female genital tract at suboptimal concentrations exert a potent selective pressure on genital HIV variants when local replication of free HIV-1 RNA persists.

Adult↗
PubMed2000

The decline of porcine sperm motility by geldanamycin, a specific inhibitor of heat-shock protein 90 (HSP90).

Sperm motility is an important parameter for fertility. The molecular mechanisms of mammalian sperm motility are still largely undefined. Our previous observations suggested that heat shock protein 90 (HSP90) may be associated with porcine sperm motility. The aim of the present study was to further characterize the plausible novel function of HSP90 on sperm motility. Semen from normal, sexually mature boars with sperm motility higher than 80% was used. An HSP90-specific inhibitor, geldanamycin (GA), was added to diluted semen at 0.5, 1.0, 2.5 or 5.0 microg/mL and the semen was then incubated at 37 degrees C for 15, 30, 45 or 60 min. Sperm motility was determined by using computer-assisted semen analyzer at the end of incubation. The results indicated that GA significantly reduced sperm motility in a dose and time dependent manner. Moreover, incubation of semen with 5.0 microg/mL GA for 15 min completely stopped sperm motility. To test the reversibility of the GA effect on sperm motility, GA was removed after 30 min incubation and was replaced with fresh extender alone or with extender plus 5 mM caffeine, then incubated for another 15, 30, 45 or 60 min. The results showed that simply removing GA did not reverse the inhibitory effect on sperm motility, while adding caffeine partially reversed this inhibitory effect. However, the effect of 2.5 or 5.0 microg/mL GA was not reversed by caffeine. Considering the specificity of GA targeting to HSP90, the above observations suggested that HSP90 may play a crucial role in regulating porcine sperm motility.

Animals↗
PubMed2000

Stage III colon cancers: why adjuvant chemotherapy is not offered to elderly patients.

HYPOTHESIS: Adjuvant chemotherapy is not offered to elderly patients with stage III colon cancer. DESIGN: A retrospective review of hospital and office records. SETTING: A suburban community hospital. PATIENTS: The medical records of 69 patients with stage III colon cancer were reviewed. All identified from the Tumor Registry at Jersey Shore Medical Center, Neptune, NJ, were included in this study. RESULTS: Thirty-five patients (51%) did not receive adjuvant chemotherapy. After adjusting for age, women were 5.8 times less likely to receive chemotherapy (P = .002). Patients not receiving chemotherapy were significantly older (78.7 vs 70.4 years; P = .003) than those who received adjuvant chemotherapy. There was no relation found between the year of diagnosis and the administration of chemotherapy. There were 4 major reasons for not receiving chemotherapy: (1) not offered (n = 12, 34%), (2) refused (n = 11, 31%), (3) too old (n = 7, 20%), and (4) significant concomitant disease (n = 5, 14%). CONCLUSIONS: A large group of elderly patients who had been surgically treated for colon cancer and who were eligible for adjuvant chemotherapy either were not referred for treatment or refused treatment. This suggests a bias on the part of surgeons, primary care physicians, and patients against the use of chemotherapy in elderly patients.

Age Distribution↗
PubMed2000

Cytotoxicity of extractives from Taiwania cryptomerioides heartwood.

The cytotoxicity of the dominant lignans and sesquiterpenoids from Taiwania (Taiwania cryptomerioides Hayata) was investigated. Three human tumor cells including A-549 lung carcinoma. MCF-7 breast adenocarcinoma and HT-29 colon adenocarcinoma were selected to illustrate the structure-cytotoxicity relationships of Taiwania's dominant compounds. Taiwanin A, taiwanin E and dimethylmatairesinol exhibited significant cytotoxicity against three human tumor cells. Among them, taiwanin A possesses the strongest cytotoxic activity. In addition, the morphology-based evaluation, flow cytometric analysis, and DNA fragmentation assays demonstrated that the tumor cell death induced by taiwanin A was due to apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Free amino acids present in commercially available seedlings sold for human consumption. A potential hazard for consumers.

The importance of fresh seedlings for human consumption on European markets continues to increase. Although the contents of free amino acids and potentially toxic free nonprotein amino acids in these fresh and supposedly healthy seedlings is very different from those of the seeds, the crude composition is never mentioned on commercial packages. A commercial product containing seven different kinds of fresh seedlings including kamut, adzuki bean, chickpea, mungbean, pinto bean, garden pea, and lentil has been analyzed by HPLC. Per 100 g of fresh product, 548.2 mg of total free amino acids was found, of which 56.7 mg is free nonprotein amino acids including beta-(isoxazolin-5-on-2-yl)alanine, homoserine, and isowillardiine and the plant hormone trigonelline (N-methylnicotinic acid). The highest amounts of free nonprotein amino acids and trigonelline are found in garden pea (28.3 mg/100 g), mungbean (9.59 mg/100 g), and lentil (7.50 mg/100 g) seedlings. Trigonelline is present in all legume seedlings examined.

Alkaloids↗
PubMed2000

Dihydrophenanthrenes from Spiranthes sinensis.

Six novel dihydrophenanthrene derivatives, sinensols A-F (1-6), were isolated from the aerial parts of Spiranthesis sinensis. Their structures were determined on the basis of various spectroscopic data, in particular those yielded by MS and 2D NMR techniques.

Magnoliopsida↗
PubMed2000

Podocarpane-type trinorditerpenes from the bark of Taiwania cryptomerioides.

Five new podocarpane-type trinorditerpenes were isolated from the bark of Taiwania cryptomerioides. Structures of 1beta, 14-dihydroxy-13-methoxy-6,8,11,13-podocarpatetraene (1), 1beta, 14-dihydroxy-13-methoxy-8,11,13-podocarpatriene (2), 13-hydroxy-12-methoxy-8,11,13-podocarpatrien-3-one (3), 14-hydroxy-13-methoxy-1,8,11,13-podocarpatetraen-3-one (4), and 13-methoxy-8,12-podocarpatriene-11,14-dione (5) were determined by NMR, MS, and other spectral and chemical evidence.

Diterpenes↗
PubMed2000

New taxanes with an opened oxetane ring from the roots of Taxus mairei.

Two novel taxoids, taxumairols N (1) and O (2), have been isolated from extracts of the roots of Taxus mairei. The structures of 1 and 2 were identified as 7beta,9alpha,10beta,13alpha-tetraacetoxy-2alp ha, 4alpha,5alpha,20-tetrahydroxytax-11-ene and 7beta,9alpha,10beta, 13alpha-tetraacetoxy-1beta,2alpha,4alpha,5alp ha, 20-pentahydroxytax-11-ene on the basis of 1D and 2D NMR techniques including COSY, HMQC, HMBC, and NOESY experiments.

Magnetic Resonance Spectroscopy↗
PubMed2000

Taraxastane-type triterpenes from the aerial roots of Ficus microcarpa.

Seven new taraxastane-type triterpenes-20-taraxastene-3beta, 22alpha-diol (1), 3beta-acetoxy-20-taraxasten-22alpha-ol (2), 3beta-acetoxy-22alpha-methoxy-20-taraxastene (3), 3beta-acetoxy-20alpha,21alpha-epoxytaraxastan-22alp ha-ol (4), 3beta-acetoxy-19alpha-methoxy-20-taraxastene (5), 3beta-acetoxy-19alpha-hydroperoxy-20-taraxastene (6), 3beta-acetoxy-20alpha,21alpha-epoxytaraxastane (7)-were isolated from the aerial roots of Ficus microcarpa. Their structures were elucidated by spectroscopic and chemical methods.

Magnetic Resonance Spectroscopy↗
PubMed2000

Inducible nitric oxide synthase inhibitors from Saposhnikovia divaricata and Panax quinquefolium.

A series of polyacetylenes, falcarinone, panaxynol, falcarindiol, panaxydol, and panaxytriol, were isolated from Saposhnikovia divaricata (Turcz.) Schischk and Panax quinquefolium L. These polyacetylenes were identified as active principles on the inhibition of nitrite production by inducible nitric oxide synthase (iNOS). Treatment with 10 microM of panaxynol, falcarindiol, panaxydol and panaxytriol decreased the LPS/IFN-gamma-stimulated accumulation of nitrite by 71.92 +/- 3.07, 69.95 +/- 3.68, 45.48 +/- 6.11 and 36.85 +/- 8.80%, respectively. The IC50 value of falcarinone, panaxynol, falcarindiol, panaxydol and panaxytriol was > 20, 2.23, 1.98, 6.58 and 9.85 microM, respectively.

Apiaceae↗
PubMed2000

Six new compounds from the heartwood of Diospyros maritima.

Six new compounds, diospyrolide (1), diospyrolidone (2), diethyl (2R)-malate (3), 3-(E)-coumaroylbetulin-28-yl ethyl nonanedioate (4), 3-(E)-coumaroylbetulin-28-yl ethyl succinate (5), and 3-(E)-coumaroylbetulin-28-yl ethyl (2R)-2-hydroxysuccinate (6), have been isolated from the heartwood of Diospyros maritima. Compounds 1 and 2 are novel trinorlupanes, and 4, 5 and 6 are lupane derivatives. Their structures were determined using spectral and chemical methods.

Magnetic Resonance Spectroscopy↗