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Biomedical subjects

Y C Hou

Publications and source records attributed to Y C Hou.

17 recordsLinked to original sources
PubMed2006

Marked decrease of cyclosporin bioavailability caused by coadministration of ginkgo and onion in rats.

Quercetin was reported to modulate CYP isoenzymes and P-glycoprotein (Pgp), a drug efflux transporter. Our previous study reported that quercetin significantly decreased the bioavailability of cyclosporin, a substrate for CYP3A4 and Pgp, in rats and pigs. Ginkgo and onion contain quercetin and its glycosides as St. John's Wort. The coadministration of cyclosporin with ginkgo or onion may be subject to clinically relevant interactions as St. John's Wort. Therefore, this study aimed to investigate the influences of ginkgo and onion on the absorption and disposition of cyclosporin in rats. Cyclosporin was administered orally and intravenously to rats with and without an oral dose of ginkgo or onion in crossover designs. Blood samples were collected via cardiopuncture and blood cyclosporin concentration was assayed by a specific monoclonal fluorescence polarization immunoassay. Everted gut sac was used to investigate the effects of ginkgo and onion on the function of intestinal Pgp. Oral coadministration of ginkgo and onion significantly decreased the Cmax of cyclosporin by 62% and 60%, and reduced the AUC0-t by 51% and 68%, respectively, whereas no influence was observed when cyclosporin was given intravenously. This indicates that the interactions between cyclosporin and ginkgo or onion occurred mainly at the absorption site. In conclusion, ginkgo and onion markedly decreased the oral bioavailability of cyclosporin. We suggest that concurrent intake of quercetin-rich herbs or foods with cyclosporin are better avoided in order to ensure the efficacy of cyclosporin.

Administration, Oral↗
PubMed2005

Effects of glucose, fructose and 5-hydroxymethyl-2-furaldehyde on the presystemic metabolism and absorption of glycyrrhizin in rabbits.

Our previous study reported that co-administration of honey significantly increased the serum levels of glycyrrhetic acid (GA) after oral administration of glycyrrhizin (GZ) in rabbits. The components of honey are sucrose, glucose, fructose and 5-hydroxymethyl-furaldehyde (HMF). To clarify the causative component(s) in honey that altered the metabolic pharmacokinetics of GZ, rabbits were given GZ (150 mg kg(-1)) with and without glucose (5 g/rabbit), fructose (5 g/rabbit) and HMF (1 mg kg(-1)), respectively, in crossover designs. An HPLC method was used to determine concentrations of GZ and GA in serum as well as GA and 3-dehydroglycyrrhetic acid (3-dehydroGA) in faeces suspension. A noncompartment model was used to calculate the pharmacokinetic parameters and analysis of variance was used for statistical comparison. Our results indicated that the area under curve (AUC) of GA was significantly increased by 29% when HMF was coadministered, whereas the pharmacokinetics of GZ and GA were not significantly altered by coadministration of glucose or fructose. An in-vitro study, using faeces to incubate GZ and GA individually, indicated that HMF significantly inhibited the oxidation of GA to 3-dehydroGA and this may explain the enhanced GA absorption in-vivo. It was concluded that HMF is the causative component in honey that affects the presystemic metabolism and pharmacokinetics of GZ in-vivo.

Administration, Oral↗
PubMed2003

Profound difference in pharmacokinetics between morin and its isomer quercetin in rats.

Morin and quercetin are isomeric antioxidant flavonols widely distributed in plant foods and herbs. The pharmacokinetics of both flavonols at two doses were investigated and compared in rats. Parent forms and their glucuronides and sulfates in serum were determined by HPLC before and after enzymatic hydrolysis, respectively. After oral dosing of morin, both the parent form, morin, and its glucuronides and sulfates were present in the bloodstream. The conjugated metabolites predominated at the dose of 25 mg kg(-1), whereas the parent form was predominant at the dose of 50 mg kg(-1). Moreover, the AUC of morin parent form increased by a factor of 37 when the dose doubled, indicating that morin showed nonlinear pharmacokinetics. On the other hand, quercetin presented only as glucuronides and sulfates in the blood, indicating negligible bioavailability of quercetin, and the metabolites showed linear pharmacokinetics at the two doses studied. When considering the total AUC of parent form with conjugated metabolites, the extent of absorption of morin was 3 fold that of quercetin at the dose of 50 mg kg(-1). The results indicated that the difference in hydroxylation pattern on B-ring of flavonol markedly affected their fates in rats.

Administration, Oral↗
PubMed2001

Effect of honey and sugars on the metabolism and disposition of naringin in rabbits.

To investigate the effect of honey and sugars on the metabolism and disposition of naringin, rabbits were administered naringin alone and naringin with honey or its component sugars - fructose, glucose and sucrose in crossover designs. An HPLC method was developed to determine naringenin in serum after enzymatic hydrolysis. Our results indicate that honey, fructose and sucrose significantly reduced AUC(0-t) of naringenin by 41 %, 61 % and 45 %, respectively. In vitro studies using a rabbit feces suspension to incubate naringin without or with honey or the respective sugars were employed to investigate the mechanism of this interaction. The results indicated that honey and its component sugars did not affect the rate and extent of naringin hydrolysis, whereas the degradation of naringenin was significantly enhanced in the presence of honey and fructose. It could be concluded that concomitant intake of honey, fructose and sucrose resulted in the reduction of naringin absorption which could be attributable in part to the enhanced preabsorption degradation of absorbable naringenin in the large intestine.

Animals↗
PubMed2001

Recurrent cardiac myxoma with multiple distant metastasis and malignant change.

A 37 year-old female underwent open heart surgery for a left atrial myxoma. The post-operative course was uneventful and she was discharged two weeks later. She had regular monthly follow-up in the outpatient department until 10 months postoperatively when she was readmitted to the orthopedic ward for excision of a left ankle tumor. Two days after admission, she developed severe orthopnea. The initial diagnosis was heart failure, and she was transferred to the medical ward for treatment. Transthoracic and transesophageal echocardiography revealed a recurrent left atrial tumor. Because of acute obstruction of the mitral valve and deterioration of her condition, she underwent emergent open heart surgery. The recurrent atrial tumor was excised; histopathologic examination revealed a myxoid sarcoma. Multiple tumors were found on this admission, including a mass in the neck and in the left forearm; computed tomography revealed a brain tumor in the left posterior frontal lobe and a chest wall tumor. She died two months later. Recurrent cardiac myxoma with multiple distant metastasis may have a malignant potential. Because of the potential for tumor recurrence, long-term and regular follow-up is mandatory.

Adult↗
PubMed2000

Effect of honey on naringin absorption from a decoction of the pericarps of Citrus grandis.

To measure naringin/naringenin absorption of a decoction prepared from the pericarps of Citrus grandis and to investigate the effect of honey on naringin/naringenin absorption, six healthy males received 200 mL decoctions of untreated and honey-treated Pericarpium Citri Grandis in a randomized crossover design. The absorption was measured by renal recovery of naringenin glucuronides/sulfates over 48 hours. The contents of naringin/naringenin in 200 mL decoctions of untreated and honey-treated Pericarpium Citri Grandis were determined to be 261.5/23.8 mumol and 303.3/11.6 mumol, respectively. The mean cumulated renal excretion of naringenin glucuronides/sulfates after intake of these two decoctions were 74.8 mumol (26.2% of dose) and 49.8 mumol (15.8% of dose), respectively. Paired Student's t-test showed that the difference of the total renal recovery of naringin/naringenin between the two decoctions was significant. The results indicated that honey significantly reduced naringin/naringenin absorption by 33.4% in humans and suggested that honey treatment might alter the efficacy of Pericarpium Citri Grandis.

Absorption↗
PubMed2000

Acute intoxication of cyclosporin caused by coadministration of decoctions of the fruits of Citrus aurantium and the Pericarps of Citrus grandis.

In order to investigate the effects of Citrus herbs on cyclosporin absorption and disposition, swine were given cyclosporin (10 mg/kg) with or without decoctions of Citri Aurantii Fructus (CAF) or Citri Grandis Pericarpium (CGP) in a crossover design. FPIA method (fluorescence polarization immunoassay) was used to determine the blood concentration of cyclosporin. The decoctions were characterized by their flavanone contents. Our results indicated that the coadministration of CAF and CGP significantly increased the Cmax of cyclosporin by 64% and 79%, respectively. The AUC of cyclosporin was significantly elevated by 97% when coadministered with CGP. Among the swine, 1/5 and 3/5 exhibited acute toxicity of cyclosporin after concomitant intake of CAF and CGP, respectively. This indicates an interaction of Citrus compounds with a commonly used drug. We suggest when cyclosporin is coadministered with these Citrus decoctions, the blood concentration of cyclosporin should be carefully monitored for dose adjustment to avoid cyclosporin intoxication.

Animals↗
PubMed2000

Honokiol and magnolol increased hippocampal acetylcholine release in freely-moving rats.

Honokiol and magnolol, phenolic compounds isolated from the stem bark of Magnolia officinalis, have been demonstrated to increase choline acetyltransferase activity, inhibit acetylcholinesterase, promote potassium-induced acetylcholine release and exhibit neurotrophic function in in vitro studies. The objective of the present study was to determine the effect of these compounds on hippocampal acetylcholine release in conscious, freely-moving rats. 10(-4) M-10(-6) M of honokiol or magnolol was perfused into rat hippocampus via a dialysis probe. The results showed that at 10(-4) M concentration, honokiol and magnolol markedly increased extracellular acetylcholine release to 165.5+/-5.78% and 237.83+/-9.47% of the basal level, respectively. However, lower concentrations of either compounds failed to elicit significant acetylcholine release. This result suggests that a high dose of honokiol or magnolol may enhance in vivo hippocampal acetylcholine release.

Acetylcholine↗
PubMed2000

New chemical and biological aspects of S-nitrosothiols.

Nitric oxide (NO) possesses many physiological effects and S-nitrosothiols have been identified in a variety of tissues exhibiting many NO-like activities. This review focuses on the latest discoveries pertaining to the biological functions of S-nitrosothiols and the recent research progress in the chemical properties and biomedical applications of RSNOs.

Animals↗
PubMed1999

Current trends in the development of nitric oxide donors.

Nitric oxide (NO) is an important messenger molecule involved in many pathological and physiological processes within the mammalian body. Exogenous NO sources constitute a powerful way to supplement NO when the body can not generate enough for normal biological functions. In this article, general aspects on NO and NO donors are reviewed. Major focus is placed on recent developments of novel NO donors, NO releasing device(s) as well as innovative improvements to current NO donors. Finally, an outlook on future NO donor development is provided.

Animals↗
PubMed1997

Shewannela putrefaciens endophthalmitis after penetrating keratoplasty.

PURPOSE: To report a case of Shewannela putrefaciens endophthalmitis after penetrating keratoplasty. METHODS: Case report. Vitreous of the recipient and the preservative medium of donor cornea were cultured. RESULTS: Vitreous of the recipient eye and the donor eye corneal preservative medium both grew S putrefaciens. The patient failed to respond to intravitreal, topical, and systemic amikacin and cefotaxime. Vision was lost rapidly. Evisceration was performed. CONCLUSION: Shewannela putrefaciens should be considered as a potential pathogen contaminating donor cornea. Shewannela putrefaciens endophthalmitis is devastating and responds poorly to medical treatment.

Adult↗
PubMed1996

Probable exclusion of GLC1A as a candidate glaucoma gene in a family with middle-age-onset primary open-angle glaucoma.

PURPOSE: To determine whether an adult-onset variety of primary open-angle glaucoma in family UM:POAG1 is linked to the previously mapped GLC1A juvenile-onset primary open-angle glaucoma locus on chromosome 1q or whether linkage can be excluded. METHODS: Microsatellite repeat markers from the 9 cM D1S196 to D1S218 interval containing the GLC1A gene were amplified by polymerase chain reaction from DNA samples collected from 11 members of one sibship in family UM:POAG1. Haplotype analysis was carried out, including calculation of the probability that the observed data would have been obtained if the underlying cause of primary open-angle glaucoma in this family were a defect in a gene located in the tested interval. Linkage analysis was carried out under an autosomal dominant model for GLC1A glaucoma. RESULTS: In family UM:POAG1, primary open-angle glaucoma was diagnosed in six surviving and one deceased member of a sibship of 13 individuals during the fifth or sixth decade of life. Glaucoma in this family has a later average age at diagnosis and significantly less elevation in intraocular pressure than GLC1A glaucoma so far described. Haplotype analysis, using a population prevalence up to 0.9%, shows that it is unlikely that the reported data would have been observed if primary open-angle glaucoma in this pedigree were due to the GLC1A locus on chromosome 1q21-q31. Linkage analysis under the juvenile glaucoma autosomal dominant model allowed exclusion of linkage across the entire GLC1A genetic inclusion interval, with a maximum lod score in the interval of -3.28. CONCLUSION: The most likely interpretation of these observations is that a defect in the GLC1A glaucoma gene is not responsible for adult-onset primary open-angle glaucoma in family UM:POAG1. This suggests the existence of at least two primary open-angle glaucoma genes, the previously reported GLC1A gene on chromosome 1q and another gene located elsewhere in the genome. Diagnosis of UM:POAG1 glaucoma between 42 and 57 years of age also raises questions regarding the relation of the glaucoma present in this family to the common later-age-onset form of the disease.

Adult↗
PubMed1993

[Observations and measurements of the valves of the orbital veins].

The lumens of the superior ophthalmic vein, the intraorbital communicating branch of the angular vein and the supraorbital vein of 19 adult male cadavers (38 orbits) were studied to find lunate venous valves in 79% of the cadavers, or 68% of the orbits. Of the 71 valves found, 39% were in the communicating branch of the angular vein, 58% in the supraorbital vein, and 2.8% in the superior ophthalmic vein. The mean distances from the valves in the communicating branch of the angular vein and those in the supraorbital vein to their junction to the superior ophthalmic vein were respectively 2.12 +/- 1.46 mm and 3.05 +/- 1.84 mm. It was important to note that the valvular sinuses opened toward the cavernous sinus.

Adult↗
PubMedDate not supplied

Linkage study of Best's vitelliform macular dystrophy (VMD2) in a large North American family.

Best's vitelliform macular dystrophy (VMD2) is an autosomal dominant retinal dystrophy for which the underlying biochemical cause is unknown. We used 11 genetic markers in the vicinity of the VMD2 gene in our study of a large North American family in which macular dystrophy characteristics overlap the broad definition of Best's disease. Significant evidence for linkage was found for markers D11S956 (Z = 5.88, theta = 0.04) and FCER1B (Z = 4.31, theta = 0.00). Recombination events localized the disease gene to the 5-cM interval D11S956-UGB, a genetic inclusion interval that substantially overlaps the VMD2 inclusion interval defined by recombinants at FCER1B and UGB observed by other research groups. The resulting exclusion of ROM1 from the genetic inclusion interval eliminates ROM1 defects as a possible cause of the disease in this family. Linkage studies of many families, including those that share most but not all features with classical Best's disease, will be needed to properly evaluate genetic heterogeneity and the range of phenotypic variation that can result from VMD2 defects.

Adult↗
PubMedDate not supplied

Characterization of low-molecular-weight glutenin subunit genes from Hordeum brevisubulatum ssp. turkestanicum.

Three novel low-molecular-weight glutenin subunit (LMW-GS) genes (designated as Ht1, Ht2, and Ht3) were isolated from the genomic DNA of Hordeum brevisubulatum ssp. turkestanicum by PCR amplification (accession no. Y0695). The coding regions of Ht1, Ht2, and Ht3 were 924, 924, and 903 bp, respectively. The deduced amino acid sequences were 306, 306, and 299 amino acid residues each with a signal peptide, a central repetitive region rich in proline and glutamine, and N- and C-terminal non-repetitive domains. A comparison was carried out of these genes with other known B hordein genes from cultivated barley and LMW glutenin genes from wheat. The results indicated that Ht1, Ht2, and Ht3 had a more similar structure and a higher level of homology with the LMW-GS genes than the B hordein genes. In order to investigate the evolutionary relationship of the novel genes with the prolamin genes from barley and wheat, the phylogenetic tree was constructed and the subfamilies of these prolamin genes were identified. The results suggested that the three novel genes were glutenin-like proteins designated as LMW-m type genes.

Amino Acid Sequence↗