Biomedical subjects

Chisato Fujiyama

Publications and source records attributed to Chisato Fujiyama.

6 recordsLinked to original sources

PubMed2005

Renal-tissue damage induced by laparoscopic partial nephrectomy using microwave tissue coagulator.

BACKGROUND AND PURPOSE: The microwave coagulator is a useful instrument that enables surgeons to perform partial nephrectomy without vascular clamping. The extent of postoperative thermal damage in surgically spared renal tissue has not been well examined. The present study was conducted to evaluate the tissue damage caused by microwave coagulation in laparoscopic partial nephrectomy (LPN) for small renal tumors. MATERIALS AND METHODS: Seven cases of LPN with a microwave tissue coagulator were entered in the present study. The median tumor diameter was 1.5 cm, and the median size of the resected specimen was 2.2 cm. Postoperative tissue damage was evaluated by contrast-enhanced CT 1 month after surgery. Surgically spared renal-tissue volume and functioning renal-tissue volume were estimated from the images by NIH Image 1.62 software. RESULTS: Postoperative CT revealed unenhanced renal tissue adjacent to the surgical margin. The median estimated volumes of surgically spared and functioning renal tissue were 96.1% (range 74.3%-99.8%) and 88.4% (range 68.0%-92.7%) of preoperative normal renal tissue, respectively. The percentile volume of functioning to surgically spared renal tissue ranged from 89.9% to 96.0% (median 92.8%). CONCLUSIONS: The microwave coagulator enables us to carry out partial nephrectomy without vascular clamping. Although 96% of normal renal tissue was surgically spared, 4% to 10% of this tissue was nonfunctioning as a result of microwave-induced thermal damage.

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PubMed2003

Nonionic contrast media are less nephrotoxic than ionic contrast media to rat renal cortical slices.

BACKGROUND: Nephrotoxicity induced by contrast media (CM) is well recognized. Nonionic CM with lower osmolality than that of conventional ionic CM have been developed in an effort to reduce toxicity. However, the nephrotoxic effects of nonionic CM have not been well evaluated. Although our previous experiments using rat renal cortical slices indicated that the direct cellular toxicity of nonionic CM is less than that of ionic CM, it was suggested that the less toxic effects of nonionic CM on the metabolic function of renal epithelial cells were in part attributable to the lower osmolality of nonionic CM. In the present experiment, the direct toxicity of nonionic CM on renal epithelial cells was compared with that of ionic CM under equiosmolar conditions, where the effects of osmotic pressure were excluded. METHODS: Rat renal cortical slices were incubated with several kinds of CM at 37 degrees C for 120 min. Diatrizoate and iothalamate were employed as ionic CM. Iopamidol and iohexol were employed as nonionic CM. The activities of N-acetyl-beta-D-glucosaminidase (NAG), gamma-glutamyltransferase (GGTP), and lactate dehydrogenase (LDH) released from the renal slices into the incubation buffer were determined in order to evaluate renal epithelial damage caused by CM. Gluconeogenesis, p-aminohippuric (PAH) acid accumulation and ATP content in rat renal slices were determined with a view to examine the inhibitory effects of CM on the metabolic function of renal epithelial cells. The toxic effects of nonionic CM were compared with those of ionic CM under equiosmolar conditions, where mannitol was added to the experimental groups containing nonionic CM in order to exclude the effects of osmotic pressure. RESULTS: A significant difference was generally not found with regard to enzyme release between ionic CM and nonionic CM plus mannitol. The inhibition of gluconeogenesis and PAH accumulation in rat renal slices by nonionic CM with mannitol was less than that by ionic CM. Although the ATP content was reduced by both ionic CM and nonionic CM plus mannitol, there was no significant difference between these two groups. CONCLUSIONS: The present experiments demonstrated that nonionic CM were less nephrotoxic than ionic CM with regard to the function of renal epithelial cells, including gluconeogenesis and PAH accumulation, under equiosmolar conditions. These differences in nephrotoxicity between ionic and nonionic CM cannot be fully attributable to differences in osmotic pressure.

Acetylglucosamine↗

PubMed2003

Expression of hypoxia-inducible factor 1alpha in human normal, benign, and malignant prostate tissue.

OBJECTIVE: To investigate hypoxia-inducible factor 1alpha (HIF-1alpha) protein expression in normal prostates (NP), benign prostatic glandular hyperplasia (BPH), and prostate adenocarcinoma (Pca). METHODS: HIF-1alpha protein expression was determined by immunohistochemistry in formalin-fixed and paraffin-embedded specimens obtained from 13 cases of NP, 28 cases of BPH, and 34 cases of Pca. In cases of Pca, the relationship between HIF-1alpha protein expression and certain clinicopathological factors, such as clinicopathologic stage and Gleason score, was evaluated. RESULTS: NP manifested no immunoreactivity, whereas Pca and BPH showed significantly increased HIF-1alpha protein expression. A significantly higher expression was observed in Pca specimens compared with BPH samples. In Pca, no significant relationship between HIF-1alpha protein expression and clinicopathological factors was found. CONCLUSION: Our findings of increased HIF-1alpha protein expression in BPH and Pca specimens suggests the potential role of this protein in BPH and Pca.

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PubMed2002

Annual PSA tests are not necessary for men with a PSA level below 2 ng/mL: findings of the Imari prostate cancer screening program.

BACKGROUND: Annual changes in prostate specific antigen (PSA) levels detected by the Imari prostate cancer screening program were evaluated to establish a more efficient and cost-saving screening system, especially for men with low PSA levels. METHODS: Prostate specific antigen-based annual mass screenings for prostate cancer were conducted for men aged 60-69 in the Imari district, Saga, Japan. Between 1992 and 2000, 1822 men had their PSA levels tested. A total of 4661 PSA tests were conducted. Changes in PSA levels over the following 1 to 5 years were analyzed in men with PSA levels of 3 ng/mL or less, a range in which the detection rate of prostate cancer would seem to be negligibly low. RESULTS: The overall detection rate of prostate cancer between 1992 and 2000 was 0.73%. The detection rate in men with a PSA level between 3.1 and 3.9 ng/mL, and between 4 and 9.9 ng/mL was 1.6% and 8.3%, respectively. Of 4661 determinations of PSA, 2553 (54.8%) were found to be < or = 1 ng/mL, 1273 (27.3%) were between 1.1 and 2 ng/mL, and 401 (8.6%) were between 2.1 and 3 ng/mL. Four hundred and thirty-four men (9.3%) had PSA levels > or = 3.1 ng/mL, with possible indications for prostate biopsy. Of the men tested, 1.4% with an initial PSA level of < or = 2 ng/mL and 22.3% with an initial level between 2.1 and 3 ng/mL had a PSA level of > or = 3.1 ng/mL after 1 year. Almost the same rate of PSA increase was observed between the two PSA tests conducted at 2 to 5-year intervals. Of the men tested, 2.2% with an initial PSA level of < or = 2 ng/mL, and 21.9% with an initial level between 2.1 and 3 ng/mL, had a level of > or = 3.1 ng/mL after 5 years. CONCLUSION: Levels of PSA in men with an initial level below 2 ng/mL remained stable for up to 5 years. Levels of PSA in 97.8- 98.8% of men remained below 3 ng/mL after 1 to 5 years. In contrast, 18-35.3% of men with an initial PSA level between 2.1 and 3 ng/mL showed PSA progression to 3.1 ng/mL or more within 5 years. Our present data suggest that annual PSA testing is not necessary for men with a PSA level below 2 ng/mL. Prostate specific antigen testing could therefore be conducted at longer intervals in such individuals.

Age Factors↗

PubMed2002

Hand-assisted retroperitoneoscopic nephroureterectomy for upper urinary-tract urothelial tumors.

PURPOSE: We report our experience with hand-assisted retroperitoneoscopic nephroureterectomy for upper urinary-tract urothelial cancer. PATIENTS AND METHODS: Our initial 10 cases of clinical stage T(1)N(0)M(0) renal pelvic and ureteral tumors treated with hand-assisted retroperitoneoscopic nephroureterectomy are included in the present report. Nephrectomy was conducted retroperitoneoscopically with hand assistance via a lower-abdominal midline incision. Resection of the lower ureter together with the bladder cuff was performed as open surgery and the specimen was removed en bloc via the same incision. RESULTS: Hand-assisted retroperitoneoscopic nephroureterectomy was completed successfully in all 10 cases. The mean operating time was 456 +/- 90 minutes, and the mean estimated blood loss was 462 +/- 364 mL. The times to oral intake and walking were 1.5 +/- 0.5 days and 2.3 +/- 0.7 days, respectively. One case of renal vein injury, one case of pulmonary embolism, and three cases of wound infection were the complications. CONCLUSION: This is the first report of hand-assisted endoscopic nephroureterectomy using the retroperitoneal approach. The surgical technique seems quite reasonable because the lower-abdominal incision can be utilized, not only as a route for hand assistance, but also as a window for open surgery when resecting the distal ureter as well as for extracting the surgical specimen.

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PubMed2002

Role of thymidine phosphorylase in an in vitro model of human bladder cancer invasion.

PURPOSE: It has been previously demonstrated that the angiogenic factor thymidine phosphorylase is elevated significantly in invasive bladder cancer. We report that it is not merely an incidental finding. Thymidine phosphorylase has a functional role in bladder cancer invasion. MATERIALS AND METHODS: The superficial bladder cancer cell line RT112 was transfected by retroviral techniques to generate the RT112-TP clone that expressed significantly elevated levels of thymidine phosphorylase, comparable to those of invasive human bladder cancers. The empty vector control RT112-EV was generated for comparison. Growth of these transfectants was examined using a new in vitro model of bladder cancer invasion based on de-epithelialized rat bladder and by assessing growth as xenografts in nude mice. The effect of 5-deoxy-5-fluorouridine, a prodrug activated by TP to produce 5-fluorouracil, was also examined. RESULTS: RT112-TP high thymidine phosphorylase expressing cells invaded into the stroma of the in vitro model but wild-type RT112 and RT112-EV cells did not. This invasion was abolished by 5-deoxy-5-fluorouridine. Invasion correlated with thymidine phosphorylase expression on immunohistochemical testing. There was also a significantly greater xenograft growth rate for RT112-TP than for RT112-EV, confirming the malignant growth advantage conferred by thymidine phosphorylase. CONCLUSIONS: We demonstrated that thymidine phosphorylase may have a functional role in bladder cancer invasion and the apparent advantage of thymidine phosphorylase expression to tumor cells can be exploited by therapies that utilize prodrugs such as 5-deoxy-5-fluorouridine, which is activated by thymidine phosphorylase and inhibited invasion in our model.

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