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Biomedical subjects

T H Hsu

Publications and source records attributed to T H Hsu.

At least 19 recordsLinked to original sources
PubMed2001

Airway hyperresponsiveness to bronchoconstrictor challenge after wood smoke exposure in guinea pigs.

Prior airway exposure to wood smoke induces an increase in airway responsiveness to subsequent smoke inhalation in guinea pigs (Life Sci. 63: 1513, 1998; 66: 971, 2000). To further characterize this airway hyperreactivity, we investigated and compared the airway responsiveness to bronchoconstrictor challenge before and 30 min after sham air exposure or wood smoke exposure in anesthetized and artificially ventilated guinea pigs. Various doses of substance P (0.8-6.4 microg/kg), capsaicin (0.2-3.2 microg/kg), prostaglandin F2alpha (30-3000 microg/kg), histamine (1-8 microg/kg), or acetylcholine (5-20 microg/kg) were intravenously injected at 2-min intervals in successively increasing doses to obtain the dose required to provoke a 200% increase in baseline total lung resistance (ED200). Wood smoke exposure significantly lowered the ED200 of substance P, capsaicin, and prostaglandin F2alpha whereas sham air exposure failed to do so. Furthermore, wood smoke exposure did not significantly alter the ED200 of histamine or acetylcholine. Pretreatment with phosphoramidon (2 mg/kg), an inhibitor of the neutral endopeptidase (the major degradation enzyme of substance P), before smoke exposure did not significantly affect the smoke-induced reduction in ED200 of substance P. Sectioning both cervical vagi before smoke exposure did not significantly alter the smoke-induced reduction in ED200 of capsaicin or prostaglandin F2alpha. These results suggest that airway exposure to wood smoke acutely produces airway hyperresponsiveness to substance P, capsaicin, and prostaglandin F2alpha, but not to histamine or acetylcholine. Since the combination of phosphoramidon and wood smoke exposure did not result in an additive potentiation of smoke-induced airway hyperresponsiveness to substance P, it is suggested that an inhibition of the degradation enzyme of substance P may contribute to this increase in airway reactivity. Furthermore, vagally-mediated bronchoconstriction does not play a vital role in enhanced airway responsiveness to capsaicin or prostaglandin F2alpha.

Acetylcholine↗
PubMed2001

Retroperitoneoscopic adrenalectomy: lateral approach.

Laparoscopy has become the essential surgical approach to the adrenal gland at many institutions, including ours. At the Cleveland Clinic, laparoscopic adrenalectomy for benign and malignant adrenal neoplasms can be performed by either the transperitoneal or the retroperitoneal approach. Herein, we present our technique of lateral retroperitoneal laparoscopic adrenalectomy.

Adrenal Gland Neoplasms↗
PubMed2001

Strategies for transplantation of cadaveric kidneys with congenital fusion anomalies.

PURPOSE: The dire shortage of cadaveric kidneys has led to a gradual expansion of donor criteria in the transplant community. The use of kidneys with anatomical fusion anomalies is uncommon and has not been well defined in the literature. We evaluated the surgical strategies and postoperative outcomes of transplanting cadaveric kidneys with congenital fusion anomalies. MATERIALS AND METHODS: Three cadaveric kidneys with congenital fusion anomalies were procured and transplanted between May 1994 and November 1999. None of the 3 donors had any significant urological history. All fusion anomalies were identified during the organ procurement process. RESULTS: Anomalies included 1 L-shaped cross-fused ectopic and 2 horseshoe kidneys. All 3 kidneys were procured en bloc. One horseshoe kidney with a narrow isthmus was split and the 2 kidneys were transplanted into separate recipients, while the other horseshoe kidney was transplanted en bloc into a single recipient. The L-shaped kidney was transplanted en bloc into 1 patient. All transplants were successful with a serum creatinine of 1.1 to 1.9 mg/dl. CONCLUSIONS: To our knowledge we present the initial case of transplantation of an L-shaped kidney. Cadaveric kidneys with congenital fusion anomalies may be transplanted successfully using various individual technical strategies based on the specific renal anatomy. As such, these kidneys may be used to maximize the increasingly inadequate donor pool.

Algorithms↗
PubMed2001

Laparoscopic repair of renal artery aneurysm.

PURPOSE: We describe technical considerations of the laparoscopic repair of a renal artery aneurysm. MATERIALS AND METHODS: A 57-year-old woman presented with a 3 cm. aneurysm of the distal left main renal artery at its bifurcation. Using a purely laparoscopic 4-port transperitoneal technique the aneurysm was completely mobilized from its location behind the renal vein. Its 3 feeding vessels were controlled individually with bulldog clamps. The aneurysm sac was bivalved and precisely trimmed to conform with the diameter of the main renal artery. Vascular reconstruction was performed with running freehand laparoscopic suturing and intracorporeal knot tying using 4-zero polypropylene suture. RESULTS: Warm ischemia time was 31 minutes, total operative time was 4.2 hours, blood loss was 100 cc and hospital stay was 2 days. Postoperatively renal scan showed improved perfusion and renal arteriography confirmed adequate repair of the aneurysm. CONCLUSIONS: Laparoscopic repair of the renal artery aneurysm is feasible. To our knowledge we present the initial clinical report of laparoscopic renovascular surgery in the literature.

Aneurysm↗
PubMed2000

Radiofrequency ablation of the kidney: acute and chronic histology in porcine model.

OBJECTIVES: To our knowledge, the chronic histopathologic effects of radiofrequency ablation (RFA) of renal parenchyma have not been extensively documented. In this study, we report the light and electron microscopic features of renal RFA in acute and chronic porcine models. METHODS: Eleven animals underwent renal RFA of the lower pole kidney bilaterally. RFA was performed laparoscopically in 6 acute animals and percutaneously in 5 chronic animals. Acute animals were killed immediately following surgery. One chronic animal each was killed on postoperative day 3, 7, 14, 30, and 90. Histopathologic evaluation of all renal tissue specimens was carried out with light and electron microscopy. RESULTS: Acutely, the renal radiolesion appeared as a yellowish white, well-circumscribed, necrotic area on gross examination, with evidence of extensive coagulative necrosis and marked inflammation on microscopic examination. From day 1 through 90, light and electron microscopy revealed evidence of progressive, irreversible cell death and necrosis with diminishing inflammatory response in the glomeruli, tubules, and renal interstitium. RFA lesions underwent gradual spontaneous resorption of the necrotic area with ultimate autoamputation. CONCLUSIONS: RFA results in necrosis of the ablated renal parenchyma.

Animals↗
PubMed2000

Laparoscopic and percutaneous radiofrequency ablation of the kidney: acute and chronic porcine study.

OBJECTIVES: The chronic effects of renal radiofrequency ablation are unknown. Herein, we investigate the anatomic and physiologic sequelae of laparoscopic and percutaneous renal radiofrequency ablation in acute and chronic porcine models. METHODS: Our study comprised two phases-an acute phase and a chronic phase. In the acute phase, bilateral laparoscopic renal radiofrequency ablation was performed in 6 animals (12 renal units), which were euthanized immediately after surgery. In the chronic study, bilateral percutaneous renal radiofrequency ablation was performed in 5 animals (10 renal units). One animal each was euthanized at postoperative day 3, 7, 14, 30, and 90. RESULTS: Ultrasound-monitored laparoscopic (n = 12) and percutaneous (n = 10) radiofrequency ablations of the lower pole of the kidney were technically successful in each instance. No intraoperative complications occurred. In the survival experiments, the radiolesions showed gradual spontaneous resorption and ultimate renal autoamputation, while maintaining pelvocalyceal integrity as confirmed by ex vivo retrograde ureteropyelogram. Serum creatinine and hematocrit remained stable in all survival animals. Postoperative complication occurred in 1 chronic animal with nonobstructive small bowel dilation at autopsy. CONCLUSIONS: Laparoscopic and percutaneous renal radiofrequency ablation are technically feasible. The anatomic and physiologic sequelae of renal radiosurgery are favorable. Improved techniques of real-time monitoring of the evolving renal radiolesion are necessary.

Animals↗
PubMed2000

Laparoscopic lymphocelectomy: a multi-institutional analysis.

PURPOSE: Because symptomatic lymphoceles are infrequent, single center studies generally report small numbers of patients. We report a multi-institutional experience with and long-term outcome following laparoscopic lymphocelectomy in 81 patients. MATERIALS AND METHODS: Data were obtained from 9 institutions at which at least 5 cases of laparoscopic lymphocelectomy had been performed. Baseline patient demographics, operative time and blood loss, special operative adjunct techniques, postoperative course, convalescence, complications and lymphocele recurrence data were collected and analyzed. RESULTS: A total of 56 men and 25 women with a mean age of 41 years were included in the study. Lymphocele formed after renal transplantation in 78 patients (96%) and after pelvic lymph node dissection in 3 (4%). Average operating time was 123 minutes with a mean blood loss of 43 ml. Omentopexy was performed in 11 cases (13.6%). No intraoperative stenting of the transplant ureter was performed. Intraoperative complications consisted of laryngospasm, bladder injury, inferior epigastric artery injury and mild renal capsule hematoma in 1 patient each. Conversion to open surgery was required for repair of bladder injury in 1, repair of preexisting hernia in 1, unusually thickened lymphocele wall in 1 and inaccessible lymphocele location in 4 cases. Mean time to ambulation and resumption of regular diet was 1 day, and mean hospital stay was 1.5 days. Postoperative complications included trocar site hernia in 1 and urinary retention in 2. Convalescence averaged 2.5 weeks. During a mean followup of 27 months 5 patients (6%) had lymphocele recurrence. CONCLUSIONS: Laparoscopic lymphocelectomy is safe, minimally invasive and effective. It is an excellent alternative to the conventional open surgical approach.

Adult↗
PubMed2000

Wood smoke-induced airway hyperreactivity in guinea pigs: time course, and role of leukotrienes and hydroxyl radical.

A prior airway exposure to wood smoke induces a tachykinin-dependent increase in airway responsiveness to the subsequent smoke inhalation in guinea pigs (Life Sci. 63: 1513, 1998). To further investigate the time course of, and the contribution of other chemical mediators to, this smoke-induced airway hyperresponsiveness (SIAHR), two smoke challenges (each 10 ml) separated by 30 min were delivered into the lungs of anesthetized guinea pigs by a respirator. In the control animals, the SIAHR was evidenced by the bronchoconstrictive response to the second smoke challenge (SM2) which was approximately 5.2-fold greater than that to the first challenge (SM1). This SIAHR was alleviated by shortening the elapsed time between SM1 and SM2 to 10 min or by extending it to 60 min, and was abolished by extending it to 120 min. This SIAHR was reduced by pretreatment with either MK-571 (a leukotriene D4-receptor antagonist) or dimethylthiourea (a hydroxyl radical scavenger), but was not affected by pretreatment with either pyrilamine (a histamine H1-receptor antagonist) or indomethacin (a cyclooxygenase inhibitor). The smoke-induced reduction in the neutral endopeptidase activity (a major enzyme for tachykinin degradation) measured in airway tissues excised 30 min post SM1 was largely prevented by pretreatment with dimethylthiourea. However, this reduction was not seen in airway tissues excised 120 min post SM1. These results suggest that 1) the SIAHR to inhaled wood smoke has a rapid onset time following smoke inhalation and lasts for less than two hours, 2) leukotrienes and hydroxyl radical may play contributory roles in the development of this SIAHR, and 3) hydroxyl radical is the major factor responsible for the smoke-induced inactivation of airway neutral endopeptidase, which may possibly participate in the development of this SIAHR.

Animals↗
PubMed2000

Thoracoscopic transdiaphragmatic nephrectomy: feasibility study.

OBJECTIVES: Large-sized upper pole renal or adrenal tumors are often excised by the open thoracoabdominal approach. As an adjunct to existing transperitoneal and retroperitoneal laparoscopic approaches, we explore a novel minimally invasive technique, the thoracoscopic transdiaphragmatic approach, for performing nephrectomy. METHODS: Thoracoscopic transdiaphragmatic nephrectomy was performed bilaterally in 4 farm pigs (8 kidneys) using three ports placed intercostally. RESULTS: The mean surgical time was 69.3 minutes on the left side and 74.3 minutes on the right. Blood loss was 18.7 mL. The mean size of the diaphragmatic incision was 7.2 cm. Adequate retraction of the spleen and liver was feasible during left and right-sided nephrectomy, respectively. Excellent and expeditious access to the renal hilum was routinely obtained. In 5 of 8 procedures, the diaphragmatic incision was located peripherally along the posterior margin; difficulty in suture repair of the diaphragmatic incision was noted in each instance because of the thin diaphragm in this location. During porcine left nephrectomy with ipsilateral lung collapse (n = 4), arterial blood gases and end-tidal carbon dioxide remained normal. CONCLUSIONS: Thoracoscopic transdiaphragmatic nephrectomy is feasible. This technique provides excellent and unique visualization of the renal vessels and the upper pole of the kidney and adrenal gland. When indicated, the thoracoscopic transdiaphragmatic approach, used in combination with current laparoscopic techniques, has the potential to provide the minimally invasive counterpart of the thoracoabdominal surgical approach in select patients with upper pole renal or adrenal pathologic findings.

Animals↗
PubMed2000

Interstitial colocalization of two cervid satellite DNAs involved in the genesis of the Indian muntjac karyotype.

A number of repetitive DNA clones were generated from PCR amplifications of Indian muntjac genomic DNA using primer sequences derived from a white tailed deer satellite II DNA sequence. One clone (Mmv-0.7) was characterized and shown to be a cervid satellite II DNA clone. Multiple colored FISH studies with cervid satellite I (C5) and this satellite II clone (Mmv-0.7) to Chinese muntjac metaphase chromosomes localized both satellite DNAs at the pericentromeric regions of all chromosomes except for chromosome 3 and the Y chromosome, whereas chromosome 3 exhibited pericentromeric satellite II DNA only. Where distinguishable, the pericentromeric satellite II signals appeared terminally oriented with respect to satellite I. Six pairs of Chinese muntjac autosomes had interstitial satellite I sites with four of these autosomal pairs (chromosomes 1, 2 and two other smaller autosomal pairs) also exhibiting interstitial satellite II signals. An interstitial site on the X chromosome was found to have satellite II signals. For the Indian muntjac chromosomes, FISH studies revealed a pericentromeric hybridization for satellites I and II as well as 27 distinct interstitial hybridization sites, each having at least one of the satellite DNAs. These data were used to more precisely define the chromosome fusion-associated breakpoints that presumably led to the formation of the present-day Indian muntjac karyotype. It further hints at the possibility that the Indian muntjac karyotype may have evolved directly from a 2n = 70 ancestral karyotype rather than from an intermediate 2n = 46 Chinese muntjac-like karyotype.

Animals↗
PubMed2000

Laparoscopic aortorenal bypass.

BACKGROUND AND PURPOSE: Open surgical renovascular repair, although producing excellent results, confers significant operative morbidity. As a result, less morbid procedures such as percutaneous balloon angioplasty and stenting have gained increasing acceptance. Laparoscopic techniques have not previously been applied to renal revascularization. The aim of this study was to demonstrate the technical feasibility and the long-term clinical and pathologic outcomes of laparoscopic aorto-left renal artery bypass in a chronic porcine model. MATERIALS AND METHODS: Eight animals were used in the study. All laparoscopic suturing and knot-tying were performed intracorporeally using free-hand techniques. The following operative steps were employed: (1) aortic dissection and cross-clamping; (2) transection and refashioning of the left renal artery ostium; (3) in-situ renal hypothermia; (4) end-to-side aorto-left renal artery anastomosis; and (5) aortic unclamping. In situ renal hypothermia was achieved laparoscopically by infusion of ice-cold heparinized saline into the renal artery through a balloon catheter. RESULTS: All eight pigs underwent laparoscopic aortorenal bypass successfully. The median surgical time was 110 minutes, and the aortic cross-clamping time was 45.5 minutes. The median anastomotic time was 40 minutes, and the renal warm ischemia time was 9 minutes. The median estimated blood loss was 30 mL. An intraoperative complication of suture breakage leading to anastomotic hemorrhage occurred in one animal; the problem was corrected laparoscopically. Postoperatively, one animal died from pneumonia. The remaining seven animals experienced no postoperative complications and were euthanized, one each at postoperative day 0 and 1 and week 1, 2, 3, 4, and 6. The median preoperative and postoperative (at euthanasia) serum creatinine values (1.15 mg/dL v 1.2 mg/dL; P = 0.39) were similar. However, compared with preoperative peripheral renin activity (0.25 microg/L per hour), the postoperative peripheral renin activity was elevated (0.9 microg/L per hour; P = 0.047). Autopsy revealed a grossly normal left kidney, with Doppler confirmation of flow in the repaired renal artery in all seven animals. Ex vivo angiography confirmed a patent anastomosis. On histopathology examination, the early left renal parenchymal specimens revealed transient, mild acute tubular necrosis that resolved over sequential specimens without significant long-term sequelae. Histologic analysis of the aorto-left renal artery anastomotic site revealed gradual endothelialization with time. CONCLUSIONS: Laparoscopic aortorenal artery revascularization is technically feasible. Our chronic animal model has demonstrated durable success over a 6-week follow-up. This study represents the initial report in the literature.

Anastomosis, Surgical↗
PubMed2000

Laparoscopic aortorenal bypass: a feasibility study.

PURPOSE: To demonstrate the technical feasibility of laparoscopic aortorenal bypass in an acute porcine model. MATERIALS AND METHODS: An aorta-to-left renal artery bypass using an interposition Dacron graft was performed in five pigs. Intracorporeal laparoscopic free-hand suturing and knot-tying were employed exclusively. Renoprotective in-situ regional hypothermia was achieved intracorporeally by infusing ice-cold heparinized saline into the renal artery using a balloon catheter. RESULTS: The mean total surgical time was 325 minutes, and the mean renal ischemia time was 61 minutes. The end-to-side graft-to-aorta and end-to-end graft-to-renal artery anastomosis times were 34 minutes and 40 minutes, respectively. The mean estimated blood loss was 66 mL. On revascularization, prompt reperfusion of the kidney and Doppler-confirmed pulsation of the renal artery was noted. Graft patency was confirmed on autopsy. CONCLUSION: Laparoscopic aortorenal bypass is feasible. This study represents the initial report in the literature. A long-term animal survival study is planned.

Animals↗
PubMed2000

Direct visualization of the genomic distribution and organization of two cervid centromeric satellite DNA families.

Several repetitive DNA fragments were generated from PCR amplifications of caribou DNA using primer sequences derived from the white-tailed deer satellite II DNA clone OvDII. Two fragments, designated Rt-0.5 and Rt-0.7, were sequenced and found to have 96% sequence similarity. These caribou clones also had 85% sequence similarity with OvDII. Multiple-colored fluorescence in situ hybridization (FISH) studies with satellite I and satellite II DNA probes to caribou metaphase chromosomes and extended chromatin fibers provided direct visualization of the genomic organization of these two satellite DNA families, with the following findings: (1) Cervid satellite I DNA is confined to the centromeric regions of the acrocentric autosomes, whereas satellite II DNA is found at the centromeric regions of all chromosomes except for the Y. (2) For most acrocentric chromosomes, the satellite I signal appeared to be medially located at the primary constriction, in contrast to that of satellite II, which appeared to be oriented toward the lateral sides as two separate fluorescent dots. (3) The satellite II clone Rt-0.7 appeared to be enriched in the centromeric region of the caribou X chromosome, a pair of biarmed autosomes, and a number of other acrocentric autosomes. (4) Fiber-FISH demonstrated that the satellite I and satellite II arrays were juxtaposed. On highly extended chromatin fibers, the total length of the hybridization signals for the two satellite DNA arrays often reached 300-400 microm. The length of a given satellite II array usually reached 200 microm, corresponding to 2 x 10(3) kb of DNA in a given centromere.

Animals↗
PubMed2000

Effects of aging on mitochondrial enzyme activity of rat urinary bladder.

OBJECTIVES: Our previous study showed that aged rat bladders became fatigued faster than young bladders following repeated contraction induced by electrostimulation. One factor might be a lower energy-producing capability secondary to a decreased mitochondrial enzyme activity of the aged bladder. This study examined this possibility. MATERIALS AND METHODS: Mitochondria from 3- (n = 11) and 24-month-old (n = 10) Sprague-Dawley rats were isolated. Activities of the following enzymes were assayed: two key enzymes in the citric acid cycle, citrate synthase and malate dehydrogenase, and three enzymes in the respiratory chain reaction, NADH-cytochrome c reductase, succinate-cytochrome c reductase and cytochrome c oxidase. The concentration of phosphocreatine and ATP in the aged rat bladders and a separate group of young bladders (n = 12) was determined using high-performance liquid chromatography. RESULTS: (1) The aged bladders have a significantly lower level of phosphocreatine and ATP content than those of young bladders. (2) The activities of all five enzymes assayed were significantly lower in the aged bladders than in young bladders, especially for citrate synthase, which had only 46.8% of the activity of young bladders. CONCLUSIONS: Aging reduces the mitochondrial enzyme activity of the rat bladder resulting in a lower energy-production capability, which might explain some of the voiding dysfunctions found in the elderly.

Adenosine Triphosphate↗
PubMed2000

Robotic remote laparoscopic nephrectomy and adrenalectomy: the initial experience.

PURPOSE: We evaluated the feasibility of performing laparoscopic nephrectomy and adrenalectomy exclusively by using robotic telepresent technology from a remote workstation and compared outcomes with those of conventional laparoscopy in an acute porcine model. MATERIALS AND METHODS: Five pigs underwent bilateral laparoscopic nephrectomy (robotic in 5 and conventional in 4) and adrenalectomy (robotic in 4 and conventional in 3). In the 9 robotic laparoscopic procedures all intraoperative manipulations were completely performed telerobotically from a remote workstation without any conventional laparoscopic assistance on site. Animals were sacrificed acutely. RESULTS: Robotic laparoscopic nephrectomy required significantly longer total operative (85.2 versus 38.5 minutes, p = 0.0009) and actual surgical (73.4 versus 27.5 minutes, p = 0.0002) time than conventional laparoscopy. However, blood loss and adequacy of surgical dissection were comparable in the 2 groups. Robotic laparoscopic adrenalectomy required longer total operative (51 versus 32.3 minutes, p = 0.13) and actual surgical (38.5 versus 18.7 minutes, p = 0.14) time than conventional laparoscopy. The solitary complication in this study was an inferior vena caval tear during robotic right adrenalectomy, which was adequately repaired by sutures telerobotically in a remote manner. CONCLUSIONS: To our knowledge we present the initial experience with remote telerobotic laparoscopic nephrectomy and adrenalectomy. Telepresent laparoscopic surgery is feasible.

Adrenalectomy↗