Biomedical subjects

Allen W Chiu

Publications and source records attributed to Allen W Chiu.

27 records · Page 2Linked to original sources

PubMed2002

Comparison study on two different accessing methods for retroperitoneoscopic adrenalectomy.

OBJECTIVES: To compare, in a retrospective nonrandomized study, two retroperitoneal laparoscopic access methods for treatment of adrenal tumors: direct needle insufflation with balloon dissection and finger-assisted dissection without balloon dissection. METHODS: The operative data from 120 consecutive patients undergoing retroperitoneoscopic adrenalectomy (RA) for benign adrenal tumors were reviewed. The operative outcomes of 70 RAs accessed by direct needle insufflation and balloon dissection were compared with another 50 RAs accessed by finger dissection without balloon dissection. The RA surgical parameters for tumors with different laterality, pathologic features, and size were also analyzed. RESULTS: The operative time in the finger dissection group was shorter (118 +/- 11 minutes) compared with that in the balloon dissection group (143 +/- 21 minutes; P = 0.03). The surgical parameters, including incidence of peritoneal perforation, intraoperative blood loss, time to oral intake, analgesic requirement, postoperative hospital stay, and convalescence, did not differ between the groups. For tumors greater than 5 cm, the operative time increased to 220 +/- 30 minutes compared with 132 +/- 31 minutes for tumors 5 cm or less (P = 0.02). The finger and balloon dissection methods had similar operative times for tumors larger than 5 cm (218 +/- 10 versus 224 +/- 15 minutes). No additional morbidity regarding the recovery time was noted in the finger dissection group compared with the balloon dissection group. CONCLUSIONS: Finger dissection appears to be a more efficient and equally effective access method for RA compared with balloon dissection. We suggest that balloon dissection may not be required for RA in patients not excessively obese.

Adrenal Gland Neoplasms↗

PubMed2002

Changes in intraocular pressure and ocular perfusion pressure after latanoprost 0.005% or brimonidine tartrate 0.2% in normal-tension glaucoma patients.

OBJECTIVE: To evaluate and compare the effects of latanoprost 0.005% once daily and brimonidine tartrate 0.2% twice daily in patients with normal-tension glaucoma (NTG). DESIGN: A randomized, open-label, crossover study. PARTICIPANTS: Twenty-eight NTG patients with progressive visual field defects/optic disc excavation, new disc hemorrhage, or field defects that threatened fixation. INTERVENTION: Patients were randomly allocated to one of two groups. Patients in group 1 were treated with latanoprost, lubricant, and brimonidine for 4 weeks each, whereas patients in group 2 were treated with brimonidine, lubricant, and latanoprost for 4 weeks each. MAIN OUTCOME MEASURES: Intraocular pressure (IOP), pulse rate, and blood pressure were measured at 8 am, 12 noon, and 4 pm after each 4-week treatment. Ocular perfusion pressure (OPP) was calculated. RESULTS: Latanoprost and brimonidine reduced the average IOP by 3.6 +/- 1.9 mmHg (P < 0.001) and 2.5 +/- 1.3 mmHg (P < 0.001), respectively, with a significant difference between the two regimens (P = 0.009). Both drugs significantly reduced IOP at each time point. Latanoprost decreased IOP significantly more than did brimonidine at 8 am (11.7 +/- 2.2 mmHg vs. 13.7 +/- 2.1 mmHg, P = 0.004) and 4 pm (11.4 +/- 2.1 mmHg vs. 13.2 +/- 2.9 mmHg, P = 0.004), but IOP was equal between the two agents at 12 noon (11.5 +/- 2.6 mmHg vs. 11.5 +/- 2.3 mmHg, P = 0.967). IOP was maintained at 12 mmHg or lower in 18 (66.7%) of 27 patients after treatment with latanoprost and in 9 (33.3%) of 27 patients after treatment with brimonidine. Latanoprost monotherapy reduced IOP by 30% in 8 patients (29.6%), but brimonidine monotherapy did not reduce IOP by that much in any of the patients. OPP increased after latanoprost treatment (P < 0.001) but did not increase after brimonidine treatment (P = 0.355). There was no significant change in pulse rate or blood pressure. CONCLUSIONS: Both latanoprost and brimonidine reduce IOP in NTG patients. Brimonidine has a peak IOP-lowering effect equal to that of latanoprost but produces a higher mean diurnal IOP than does latanoprost because of its shorter effect. Latanoprost might favorably alter optic disc blood perfusion by increasing OPP.

Adrenergic alpha-Agonists↗

PubMed2002

Use of latanoprost to reduce acute intraocular pressure rise following neodymium: Yag laser iridotomy.

PURPOSE: To evaluate the efficacy of latanoprost in reducing acute intraocular pressure (IOP) elevation after neodymium:Yag laser iridotomy (LI). METHODS: Primary angle-closure glaucoma (PACG) eyes were randomized to receive premedication with latanoprost and pilocarpine or with pilocarpine only before LI. Postoperative IOP changes were compared with Wilcoxon signed-ranks test using the fellow eyes of 47 patients who had one eye in each group. RESULTS: Postoperative pressure spikes were significantly lower (p = 0.010) in the latanoprost group (4.1 +/- 5.0 mmHg) than in the control group (6.7 +/- 7.0 mmHg). Mean elevation of IOP was less in the latanoprost group than in the control group at 1 hour (2.5 +/- 4.8 versus 4.1 +/- 4.7 mmHg, p = 0.013) and 2 hours (0.8 +/- 5.6 versus 4.4 +/- 8.1 mmHg, p = 0.003) postoperatively. Eleven eyes in the latanoprost group (23.4%) and 20 eyes in the control group (42.6%) developed a rise in IOP > or = 6 mmHg (p = 0.048). CONCLUSION: Latanoprost may reduce the pressure rise following LI in PACG eyes, but its application is limited by a late onset of effect.

Acute Disease↗

PubMed2002

Establishment of a mini-gene expression database for bladder tumor.

BACKGROUND AND PURPOSE: Transitional cell carcinoma has been diagnosed mostly in urinary bladder in southern Taiwan and has an exceptionally high mortality rate. To identify the genes associated with bladder cancer, we investigated differential gene expression. Six bladder tumor cDNA libraries were constructed and their sequences were compared and analyzed. METHODS: mRNA from bladder tumor cell lines or tissue samples were used to construct two regular cDNA libraries and four subtractive cDNA libraries after subtractive hybridization with cDNA derived from normal bladder epithelial cells. Subsequently, more than 100 cDNA inserts from each library were randomly isolated and sequenced, followed by sequence comparisons with nucleotide and protein sequence databases. RESULTS: After searching the Basic Local Alignment Search Tool (Blast) databases, the cDNA nucleotide sequences were grouped into novel, known, and common gene categories. Since tumor nucleotide sequences are informative and valuable for research, they were organized as a mini-gene expression database (http://bladder.nhri.org.tw/). Interestingly, in one subtractive cDNA library, the ATPase 6 gene was found to be highly expressed in normal bladder epithelial cells and elevated levels of ATPase 6 mRNA were later confirmed by reverse transcription-polymerase chain reaction. However, the role of ATPase 6 in bladder tumorigenesis remains to be investigated. CONCLUSIONS: The establishment of this database is an important step to enable systematic screening for bladder tumor-associated genes and may also be useful in developing diagnostic and/or therapeutic applications.

Adenosine Triphosphatases↗

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↗

PubMedDate not supplied

Efficacy of ultrasonic tissue dissector and tissue glue for laparoscopic partial nephrectomy in a porcine model.

The purpose of this study was to evaluate the efficacy and long-term tissue effects of ultrasonic dissector and cyanoacrylate glue during laparoscopic partial nephrectomy in a porcine model. Nine domestic pigs underwent laparoscopic left lower pole partial nephrectomy without vascular control. An ultrasonic tissue dissector was used to assist in the parenchymal incision, and the raw surfaces of the kidneys, including the exposed urinary system, were sealed with cyanoacrylate glue. No internal stents or additional sutures were placed. Intraoperative hemorrhages and urinary extravasation were recorded. The animals were humanely killed 28 days after undergoing the operations. The long-term effects of ultrasonic dissector and cyanoacrylate glue on the healing process of urothelium and renal parenchyma were determined histologically. All pigs survived the laparoscopic partial nephrectomy, and the blood loss ranged from 0 to 120 ml (mean, 60 ml). The average operative time was 89 +/- 10 min. The severity of the bleeding was minimal in six animals and moderate in three animals. No urinary extravasation was found using intravenous urography at the 28th postoperative day. No urinary fistula or renal abscess formation was found histologically. Cyanoacrylate glue infiltrated into the tissue defects and did not dissolve. The glue was encased by fibrotic tissue with minimal foreign body inflammatory reaction. Ultrasonic dissector was effective in achieving hemostasis during laparoscopic partial nephrectomy without the need of vascular control in pigs. Cyanoacrylate glue achieved good long-term adhesive power. The sealing effects provided by cyanoacrylate glue were adequate to prevent urinary extravasation from urothelial defects at least for 1 month.

Animals↗

PubMedDate not supplied

Differential expression of molecular markers in arsenic- and non-arsenic-related urothelial cancer.

BACKGROUND: Little is known about the mechanisms of arsenic-related urothelial cancer (AsUC). The aim of this study was to reveal the differential expression of molecular markers between AsUC and non-arsenic-related UC (non-AsUC). MATERIALS AND METHODS: Tissues of AsUC (n=33), non-AsUC (n=20) and normal bladder urothelia from patients with benign diseases (n=4) were examined for multiple selected molecular markers responsible for various cellular functions, includingglutathione, GST-pi, Bcl-2, p53 and c-Fos. RESULTS: The mean cellular glutathione content of normal mucosal samples (33.4 +/- 7.2 microM/mg protein) was significantly higher than either non-AsUC (22.8 +/- 1.8, p = 0.04) or AsUC (16.4 +/- 1.6, p = 0.002). The glutathione content of non-AsUC was higher than that of AsUC (p = 0.012). The expressions of Bcl-2 and c-Fos in AsUC were significantly higher than those in non-AsUC (p = 0.004 and p = 0.02, respectively). CONCLUSION: The carcinogenic pathway for AsUC is different, in part, from that of non-AsUC. Cellular glutathione contents may be down-regulated during urothelial carcinogenesis. Bcl-2 and c-Fos may play important roles in arsenic-mediated carcinogenesis of the urothelium.

Arsenic Poisoning↗