Biomedical subjects

Allen W Chiu

Publications and source records attributed to Allen W Chiu.

11 recordsLinked to original sources

PubMed2003

Laparoscopic retroperitoneal adrenalectomy: clinical experience with 120 consecutive cases.

OBJECTIVE: Surgical parameters of laparoscopic retroperitoneal adrenalectomy (LRA) for the treatment of benign adrenal tumours were analysed to report the clinical outcomes and technical guidelines for this operation. METHODS: Operative data from 120 consecutive patients who underwent LRA performed by a single surgeon were reviewed. Patients were categorized into one of four stages according to the major technical modifications made during the development of this procedure: needle insufflation, kidney localization, instrument refinement, and the final stage of finger dissection. The surgical parameters of different stages were evaluated, including operation time, operative blood loss, adenoma size, pathology, surgical complications, morbidity, and postoperative recovery. RESULTS: LRA was an evolving technique; operation time and conversion rate decreased gradually as the technique evolved over the years. Operation time was reduced particularly when finger dissection was used to develop the operative working space. Operation time reached a nadir of 80 minutes for patients with left adrenal aldosteronoma after 40 such cases. The overall conversion rate, regardless of the nature of the tumour, was 5%; phaeochromocytoma had the highest conversion rate (43%). A higher conversion rate and longer operation time were noted in patients with Cushing's adenoma or phaeochromocytoma compared to patients with aldosteronoma. CONCLUSION: LRA proved to be a safe and effective treatment for benign adrenal tumours, with few open conversions except for phaeochromocytomas. Finger-assisted dissection for space development was the major factor leading to shortened operation times.

Adrenal Gland Neoplasms↗

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↗

PubMed2003

Novel intracorporeal vascular knot applier for large vessel ligation in laparoscopic surgery: experience in pigs and preliminary clinical use.

BACKGROUND AND PURPOSE: We designed an intracorporeal knot applier for the ligation of large vessels laparoscopically. The aim of this study was to assess the efficacy and efficiency of this method to control large vessels in pigs. MATERIALS AND METHODS: Six pigs with mean body weight of 28 kg (range 26-30 kg) were enrolled. The standard transperitoneal laparoscopic set-up was established with 15 mm Hg of pneumoperionteum. The right renal hilum was mobilized, and the renal artery and renal vein were separated. A 5-cm segment of inferior vena cava with the right renal vein was skeletonized laparoscopically. Assisted by the novel knot applier, 3-0 silk was used to ligate the renal artery, renal vein, and inferior vena cava. The time required to accomplish these ligatures was recorded. Two intracorporeal knots were applied 5 mm apart, and the vessels were divided between the knots. The knot strength was assessed by measuring the maximal intraluminal pressure required to blast out the knot using gas insufflation. RESULTS: The diameters (mean +/- SD) of the porcine inferior vena cava, renal artery, and renal vein were 11.1 +/- 0.7, 2.9 +/- 0.3, and 4.9 +/- 0.3 mm, respectively. The knotting time was 58.9 +/- 8.6, 57.5 +/- 6.6, and 59.1 +/- 6.3 seconds for these vessels, respectively. No bleeding occurred when the vessels were divided. The average pressure needed to withstand the blast out of the ligature on the inferior vena cava, renal artery, and renal vein was 213.3 +/- 32.7 (range 165-250), 227.5 +/- 14.7 (range 210-250), and 210.8 +/- 21.5 (range 180-240) mm Hg, respectively. CONCLUSIONS: The novel intracorporeal knot applier was easy to use when making a ligature on vessels of different sizes and different wall thicknesses. The time required for making a ligature was short, and the knot was secure enough to withstand a vascular pressure higher than ordinary blood pressure. The laparoscopic device is inexpensive with great potential of being used as a secure vascular ligature provider.

Animals↗

PubMed2002

Modulation of dendritic cell differentiation and maturation by decoy receptor 3.

Decoy receptor 3 (DcR3), a soluble receptor belonging to the TNFR superfamily, is a receptor for both Fas ligand (FasL) and LIGHT. It has been demonstrated that DcR3 is up-regulated in lung and colon cancers, thus promoting tumor growth by neutralizing the cytotoxic effects of FasL and LIGHT. In this study, we found that DcR3.Fc profoundly modulated dendritic cell differentiation and maturation from CD14(+) monocytes, including the up-regulation of CD86/B7.2, and the down-regulation of CD40, CD54/ICAM-1, CD80/B7.1, CD1a, and HLA-DR. Moreover, DcR3-treated dendritic cells suppressed CD4(+) T cell proliferation in an allogeneic MLR and up-regulated IL-4 secretion of CD4(+)CD45RA(+) T cells. This suggests that DcR3.Fc may act not only as a decoy receptor to FasL and LIGHT, but also as an effector molecule to skew T cell response to the Th2 phenotype.

Adjuvants, Immunologic↗

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↗

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

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↗