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Yu-Lun Huang

Publications and source records attributed to Yu-Lun Huang.

12 recordsLinked to original sources
PubMed2006

Intermolecular arene C-H activation by nickel(II).

Intermolecular arene C-H activation mediated by a divalent nickel species under extremely mild conditions is described. The reactions of either Ni(COD)2 with H[N(o-C6H4PR2)2] (H[R-PNP]; R = iPr, Cy) in benzene at room temperature or [R-PNP]NiCl with LiBHEt3 in THF at -35 degrees C produced the corresponding [R-PNP]NiH in high yield. Addition of 1 equiv of B(C6F5)3 to a benzene solution of [R-PNP]NiH at room temperature led to the formation of a mixture that contains [R-PNP]NiPh and [R-PNP]Ni(C6F5), both of which are proposed to evolve from zwitterionic [R-PNP]Ni(mu-H)B(C6F5)3. In contrast, the reaction of [R-PNP]NiH with AlMe3 in benzene at room temperature afforded exclusively the corresponding [R-PNP]NiPh. Similar results were also observed for intermolecular toluene and m-xylene C-H activation by [R-PNP]NiH. A parallel study involving [R-PNP]NiMe (R = Ph, iPr, Cy) on the reactivity of intermolecular arene activation reveals the significance of pi basicity of Ni(II) in these molecules. The remarkable reactivity of inexpensive Ni(II) species established in this study is attractive, particularly from an economic viewpoint, as compared to the current alternatives of 4d and 5d metals.

Journal Article↗
PubMed2005

Enhanced transformation and chemosensitivity of NIH3T3 cells transduced with hepatoma up-regulated protein.

Hepatoma up-regulated protein (HURP) is a recently identified novel cell-cycle-regulated gene. The HURP gene is overexpressed in human hepatocellular carcinoma and transitional cell carcinoma. The cellular function of HURP is not fully understood. In this study, the NIH3T3 cells transduced with the exogenous HURP gene manifested the general characteristics of tumor cells, which had higher growth rate in low-serum media and advanced ability of colony formation on agarose-based plates. Transduced HURP was capable of specifically enhancing the chemosensitivity of deoxycytosine analogs, such as gemcitabine, ARA-C, and 5-AZA-CdR, but neither had an effect on the response of DNA intercalating agents, such as cisplatin, carboplatin, and doxorubicin, nor on the response of microtubule stabilizers, such as paclitaxel, docetaxel, and vinblastine. These results indicate that the HURP gene might be a potential oncogenic gene and capable of enhancing the chemosensitivity of deoxycytosine analogs in NIH3T3 cells.

Animals↗
PubMed2005

Typhoid fever complicated by multiple organ involvement: report of two cases.

Typhoid fever complicated by multiple organ involvement has been rarely mentioned in the literature. We reported two cases of typhoid fever with several unusual manifestations, including acute renal failure, acute hepatitis, acute pancreatitis, disseminated intravascular coagulation, and lower gastrointestinal bleeding. A renal biopsy in the first case showed no pathological change. Bone marrow biopsy showed focal necrosis of matrix, which might have been due to severe illness. A liver biopsy in the second case showed a predominantly histiocytic proliferation with occasional neutrophilic infiltration in the portal areas and hepatic sinusoids. Focal necrosis, bile duct injury, and multiple eosinophilic bodies were also noted. After appropriate antimicrobial therapy, both patients recovered without any sequelae. The potential of multiple organ involvement is highlighted in typhoid fever, which, on rare occasions, may occur simultaneously in the same patient.

Acute Disease↗
PubMed2004

Thrombospondin-1 mediates distal tubule hypertrophy induced by glycated albumin.

Diabetic nephropathy is characterized by early hypertrophy in both glomerular and tubuloepithelial elements. However, no studies to date have established a direct causal link between hyperglycaemia and renal hypertrophy. Our previous studies have found that high glucose does not induce cellular hypertrophy or expression of TGF-beta1 (transforming growth factor-beta1) in distal renal tubule cells [Yang, Guh, Yang, Lai, Tsai, Hung, Chang and Chuang (1998) J. Am. Soc. Nephrol. 9, 182-193]. In the present study, we used AGEs (advanced glycation end-products) to mimic long-term hyperglycaemia. Similar to glucose, AGEs did not induce TGF-beta1 mRNA in distal renal tubule cells [MDCK (Madin-Darby canine kidney) cells]; however, TGF-beta1 bioactivity was increased significantly. This result indicated post-translational regulation. Since TSP-1 (thrombospondin-1) has been demonstrated to activate latent TGF-beta1 in a variety of systems, the following experiments were performed. We found that AGEs dose-dependently increased both intracellular and extracellular levels of TSP-1. Purified TSP-1, like AGEs, increased the cellular protein content. Furthermore, anti-TSP-1 neutralizing antibodies attenuated the AGE-induced increase in TGF-beta1 bioactivity and hypertrophy. Thus TSP-1 might mediate AGE-induced distal renal tubule hypertrophy. In addition, we observed several putative transcription factor binding sites in the TSP-1 promoter, including those for AP-1 (activator protein-1), CREB (cAMP response element binding protein), NF-kappaB (nuclear factor-kappaB), SRF (serum response factor) and HSF (heat-shock factor), by sequence mapping. We used an enhancer assay to screen possible transcription factors involved. We showed that AP-1 and CREB were specifically induced by AGEs; furthermore, TFD (transcription factor decoy) for AP-1 could attenuate the AGE-induced increases in TSP-1 levels and cellular hypertrophy. Thus regulation of TSP-1 might be critical for hyperglycaemic distal tubule hypertrophy. Furthermore, TSP-1 TFD might be a potential approach to ameliorate diabetic renal hypertrophy.

Animals↗
PubMed2004

Altered transcripts expression of matrix metalloproteinases and their tissue inhibitors in tenon capsule of patients with glaucoma.

PURPOSE: To determine the transcripts expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in Tenon capsule of patients with primary glaucoma and non-glaucomatous patients who serve as the control. PATIENTS AND METHODS: Specimens of Tenon capsule were obtained intraoperatively and evaluated with the reverse transcriptase-polymerase chain reaction method. The transcripts levels of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 relative to that of glyceraldehyde phosphate dehydrogenase were determined. RESULTS: The transcripts levels of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 were not correlated with age in the control group. There were differences in the transcripts expression of MMP-2 (P < 0.001), MMP-9 (P = 0.017), TIMP-1 (P < 0.001), and TIMP-2 (P = 0.001) among the control, primary open angle glaucoma, and primary angle-closure glaucoma groups (Kruscal-Wallis H test). Comparing with the controls, open angle glaucoma had decreased transcripts levels of MMP-2 (P = 0.001) and TIMP-1 (P = 0.006) while angle-closure glaucoma had decreased transcripts levels of MMP-2 (P < 0.001), MMP-9 (P = 0.004), TIMP-1 (P < 0.001), and TIMP-2 (P < 0.001) (Mann-Whitney U tests). CONCLUSION: The transcripts expression of certain MMPs and TIMPs is altered in Tenon capsule of glaucoma patients, which might result from long-term application of topical glaucoma medications.

Adolescent↗
PubMed2003

Regulation of type II transforming-growth-factor-beta receptors by protein kinase C iota.

TGF-beta (transforming growth factor-beta) is implicated in the pathogenesis of diabetic nephropathy. We previously demonstrated that up-regulation of type II TGF-beta receptor (TbetaRII) induced by high glucose might contribute to distal tubular hypertrophy [Yang, Guh, Yang, Lai, Tsai, Hung, Chang and Chuang (1998) J. Am. Soc. Nephrol. 9, 182-193]. We have elucidated the mechanism by using cultured Madin-Darby canine kidney cells. Enhancer assay and electrophoretic-mobility-shift assay were used to estimate the involvement of transcription factors. Western blotting and an in vitro kinase assay were used to evaluate the level and activity of protein kinase. We showed that glucose (100-900 mg/dl) induced an increase in mRNA level and promoter activity of TbetaRII (note: 'mg/dl' are the units commonly used in diabetes studies). The promoter region -209 to -177 appeared to contribute to positive transactivation of TbetaRII promoter by comparing five TbetaRII-promoter-CAT (chloramphenicol acetyl-transferase) plasmids. Moreover, the transcription factor AP-1 (activator protein 1) was significantly activated and specifically binds to TbetaRII promoter (-209 to -177). More importantly, we found that atypical PKC iota might be pivotal for high glucose-induced increase in both AP-1 binding and TbetaRII promoter activity. First, high glucose induced cytosolic translocation, activation and autophosphorylation of PKC iota. Secondly, antisense PKC iota expression plasmids attenuated high-glucose-induced increase in AP-1 binding and TbetaRII promoter activity; moreover, sense PKC iota expression plasmids enhanced these instead. Finally, we showed that antisense PKC iota expression plasmids might partly attenuate a high-glucose/TGF-beta1-induced increase in fibronectin. We conclude that PKC iota might mediate high-glucose-induced increase in TbetaRII promoter activity. In addition, antisense PKC iota expression plasmid effectively suppressed up-regulation of TbetaRII and fibronectin in hyperglycaemic distal-tubule cells.

Analysis of Variance↗
PubMed2003

Creation of ureteropelvic junction obstruction and its correction by chemical glue-assisted laparoscopic dismembered pyeloplasty.

PURPOSE: We established a porcine model of ureteropelvic junction (UPJ) obstruction using a laparoscopic technique and assessed the outcome of standard suture-assisted and chemical glue-assisted laparoscopic pyeloplasty. MATERIALS AND METHODS: Female domestic pigs (N = 20) underwent laparoscopic suture-ligature to create UPJ obstruction. One month later, laparoscopic end-to-end anastomosis was performed to correct the obstruction: with standard suturing techniques in 10 animals and with chemical (cyanoacrylate) glue in the other 10. Postoperative ureteral stents were not used. Four weeks postoperatively, intravenous urography was performed to evaluate the patency of the anastomoses. The UPJ was procured by laparotomy to assess the anastomoses and periureteral fibrosis histologically. RESULTS: The UPJ obstruction was created in an average of 15 +/- 6 minutes. There was no early postoperative mortality. Eighteen pigs survived for at least 1 month, and UPJ obstruction developed in 17 (95%). Microscopically, the lumen of the UPJ was partially occluded, measuring an average of 40% +/- 5% of normal. After laparoscopic correction, a patent UPJ was found in seven of nine animals treated with traditional sutures. Among the eight animals with chemically glued anastomoses, none had a patent UPJ, and severe periureteral adhesions and intraluminal fibrosis were noted at the pyeloplasty site. Marked ureteral tortuosity was present in six of the eight pigs receiving glue-assisted pyeloplasty but in none of the animals having suture-assisted pyeloplasty. CONCLUSIONS: Ureteropelvic junction obstruction was established by laparoscopic suture-ligature in a porcine model with a 95% success rate. Chemical glue-assisted anastomosis was inferior to standard laparoscopic sutures for pyeloplasty to correct the obstruction.

Adhesives↗
PubMed2002

Potential molecular marker for detecting transitional cell carcinoma.

OBJECTIVES: To assess the expression rate of a cancer-related gene, hepatoma-up-regulated protein (HURP), in the tumor tissue of transitional cell carcinoma (TCC), and to assess the potential suitability of using this gene as a novel molecular marker for detecting TCC in voided urine. METHODS: Total RNA was extracted from 80 TCC tissue samples of the urinary tract. Forty-five of the 80 tumor-adjacent tissue samples were from the same patients and 15 were from control subjects (patients with benign prostatic hyperplasia). The expression levels of HURP mRNA in these specimens were examined using reverse transcriptase-polymerase chain reaction. The HURP mRNA transcripts in voided urine pellets from 14 additional patients were determined using the same method. The messages were normalized to beta-actin mRNA. RESULTS: The detection of HURP expression in the TCC tissue samples had a sensitivity of 88.8% (71 of 80) and a specificity of 100% (15 of 15). Ten of the 45 grossly tumor-adjacent tissue samples expressed HURP mRNA, which may indicate subtle genetic changes in tissue adjacent to tumor. All seven urine specimens from the patients with TCC revealed HURP expression; however, no specimens from patients with nonmalignant diseases did so. CONCLUSIONS: A potential molecular marker for detecting TCC with tissue specimens and voided urine samples has been found. Although the real clinical application of this marker requires additional evaluation, the high sensitivity and specificity of the HURP gene amplification method warrants more investigation in the future.

Biomarkers, Tumor↗
PubMedDate not supplied

A feasible tool to detect mRNA expression of matrix metalloproteinases and their tissue inhibitors in human Tenon's capsule.

PURPOSE: To determine the mRNA expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in human specimens of Tenon's capsule. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) with specific primers for MMP-1, MMP-2, MMP-9, TIMP-1 and TIMP-2 was performed on tissue specimens obtained from patients with cataract, rhegmatogenous retinal detachment, glaucoma, or diabetes mellitus. RESULTS: Glyceraldehyde phosphate dehydrogenase (GAPDH) mRNA transcripts were detected in 26 (76.5%) of 34 specimens, with almost the same amount of expression in each of these samples. Messenger RNA expression of one or more of the MMPs/TIMPs could also be detected in all of these 26 samples, but not in any sample without GAPDH expression. MMP-2, TIMP-1 and TIMP-2 were detected in 25 (96.2%) of the 26 samples with GAPDH expression, while MMP-1 and MMP-9 were detected with a lower percentage (34.6 and 19.2%, respectively). CONCLUSION: The feasibility of RT- PCR with GAPDH as an internal standard to determine mRNA transcripts of the MMPs and TIMPs in the subconjunctival Tenon's capsule was demonstrated.

Conjunctiva↗
PubMedDate not supplied

Transcript expression of matrix metalloproteinases in the conjunctiva following glaucoma filtration surgery in rabbits.

PURPOSE: To determine the changes in the expression of transcripts of matrix metalloproteinases (MMPs) and their tissue inhibitor (TIMP) in the conjunctiva following glaucoma filtration surgery (GFS). METHODS: The reverse transcription-polymerase chain reaction method was performed on tissue specimens obtained from adult rabbits undergoing GFS at various postoperative time points. RESULTS: MMP 1 decreased more than 7-fold from its baseline level during the first 2 weeks following surgery. MMP 2 decreased on the 1st postoperative day, but increased on day 2, and remained elevated for 2 weeks. The postoperative level of MMP 14 did not change much from baseline except that noted on day 9. The TIMP 1 expression showed an early biphasic pattern. MMP 3 and MMP 9 were not detected in all the specimens. CONCLUSIONS: The transcript expression of MMPs and TIMP 1 in the conjunctiva is altered following GFS, with each gene product demonstrating a unique temporal pattern.

Animals↗
PubMedDate not supplied

Prognostic significance of hepatoma-up-regulated protein expression in patients with urinary bladder transitional cell carcinoma.

We recently found a urinary molecular marker, Hepatoma-Up-Regulated Protein (HURP), for the detection of urinary bladder transitional cell carcinoma (TCC). In this study, the expression of HURP in 57 voided urine specimens was determined by semi-quantitative reverse transcriptase-polymerase chain reaction. HURP value was correlated with a variety of clinical parameters, including sex, age, tumor grade, stage, multiplicity, tumor shape and recurrence/metastasis during the follow-up period. The detection rate of HURP was 60.7% (17 out of 28) in voided urine of patients with TCC, 5.9% (1 out of 17) in non-TCC urological benign disease and 0% (0 out of 12) in healthy volunteers. HURP positivity (defined as above 0.1 cut-off value) was detected in 83.6% (92 out of 110) TCC specimens, 4.3% (1 out of 23) of non-TCC urinary cancer and 0% (0 out of 15) of benign urological disease. No relationship was found between the level of HURP and the above-mentioned clinical parameters other than recurrence of TCC patients. A higher level of tissue HURP was found in the patients having recurrence (Mann-Whitney U-test, p = 0.027).

Aged↗