Biomedical subjects

Jiro Uozumi

Publications and source records attributed to Jiro Uozumi.

7 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.

Aged↗

PubMed2005

[A modified retroperitoneal approach to the kidney in patients with a highly deformed thorax: obtaining a wide operative field through subperiosteal resection of the 10th, 11th and 12th ribs].

We herein report a technique which facilitates a retroperitoneal approach to the kidney in cases of highly deformed thorax due to kyphoscoliosis. The operation consists of a lumbar oblique incision with removal of the 11th rib, combined with the additional removal of the 12th and 10th ribs. Resection of the upper two ribs was performed subperiosteally, leaving the periosteum of the deep side untouched. However, the deep side periosteum of the 12th rib was incised caudal from the pleural margin in order to facilitate exposure of the diaphragm. The retroperitoneal space was entered through the tip of the 11th rib bed. The diaphragm was incised dorso-medially at a level 1 cm caudal from the lower margin of the pleura, to an extent necessary to enable the pleura together with the cranial diaphragm to be manoeuvred in an upward direction. Two cases with renal tuberculosis associated with high-grade kyphosis and one case with staghorn calculi accompanied with lordosis were operated on utilizing this technique. In the former two cases, the thoracic cage was in direct contact with the iliac bone and there was practically no space between the rib border and the iliac crest. This was also true of the third case, but the grade of deformity was not as extensive as in the former two cases. Removal of the 10th, 11th and 12th ribs could be achieved without injuring the pleura and a satisfactorily large operating field could thus be developed which enabled a simple nephrectomy to be performed without difficulty. The characteristic feature of the described approach is that resection of the 10th and 11th ribs is simply to facilitate manoevrability of the wound margin, without going through the rib bed. The technique could be advantageous in selected cases where there is a highly deformed thorax.

Humans↗

PubMed2004

Experimental study of renal disorder caused by oxaliplatin in rat renal cortical slices.

BACKGROUND: Oxaliplatin is a newly developed antitumor platinum complex that is known to have low nephrotoxicity. The inhibitory effects of oxaliplatin on several tubular functions were compared with those of cisplatin and carboplatin, using a renal cortical slice system. METHODS AND RESULTS: Rat renal cortical slices were incubated with 0.25 mM to 2.0 mM of oxaliplatin, cisplatin, on carboplatin at 37 degrees C for 120 min. Para-amino hippuric acid (PAH) accumulation, gluconeogenesis, and ATP content in the rat renal slices were determined. PAH accumulation was not inhibited by carboplatin, but it was significantly inhibited by oxaliplatin and cisplatin. Inhibition of PAH accumulation by cisplatin was greater than that by oxaliplatin. Gluconeogenesis was not decreased by carboplatin, but it was suppressed by oxaliplatin and cisplatin in a dose-dependent manner. The decrease in gluconeogenesis induced by oxaliplatin was significantly greater than that induced by cisplatin. ATP content in the renal slices was decreased by oxaliplatin, cisplatin, and carboplatin to almost the same extent. As an in vivo experiment, 21.6 mmole/kg of oxaliplatin, cisplatin, or carboplatin was injected into rats; then blood urea nitrogen (BUN) and serum creatinine were determined on day 4. Significantly elevated levels of BUN and serum creatinine were observed only in the rats injected with cisplatin. CONCLUSIONS: Oxaliplatin did not cause nephrotoxicity in the in vivo study; however, the nephrotoxic pattern of oxaliplatin observed in the renal cortical-slice system resembled that of cisplatin. The reason why oxaliplatin is less nephrotoxic than cisplatin in vivo could not be fully elucidated in the present experiment using the renal cortical-slice system.

Animals↗

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

Inhibition of gluconeogenesis and p-aminohipuric acid accumulation in rat renal cortical slices by ionic and nonionic contrast media.

BACKGROUND: Renal dysfunction is a well-recognized complication induced by contrast media (CM). Nonionic CM have been introduced into clinical use to replace conventional ionic CM in an effort to reduce toxicity. However, the nephrotoxic effects of nonionic CM have not been fully evaluated. We previously determined the activities of N-acetyl-beta- d-glucosaminidase and gamma-glutamyltransferase released from rat and human renal slices incubated with contrast media. Dose-dependent enzyme release from renal slices was observed, but there was no statistical difference in the increase of enzyme activities between ionic and nonionic CM. The present experiment was conducted to compare the effects of ionic and nonionic CM on the metabolic function of rat renal slices. METHODS: Rat renal cortical slices were incubated with ionic CM (diatrizoate, iothalamate) and nonionic CM (iopamidol, iohexol) at 37 degrees C for 90 min. To examine the dose-response effects of CM on gluconeogenesis and p-aminohipuric acid (PAH) accumulation in the rat renal slices, slices were incubated with 30, 60, and 90 mg I/ml of CM. The inhibitory effects of nonionic CM on gluconeogenesis and PAH accumulation were compared with those of ionic CM in an independent experiment, in which slices were incubated with CM at a concentration of 60 mg I/ml. In addition, rat renal slices were incubated with mannitol instead of CM to investigate the effects of osmotic pressure on gluconeogenesis and PAH accumulation. RESULTS: A dose-dependent reduction of gluconeogenesis in rat renal slices was demonstrated by both ionic CM and nonionic CM. The inhibition of PAH accumulation was dose-dependent with nonionic CM, but not with ionic CM. Gluconeogenesis and PAH accumulation within the renal slices were both inhibited according to the increase in osmotic pressure produced by mannitol. The reduction in gluconeogenesis and PAH accumulation within the rat renal slices incubated with 60 mg I/ml of nonionic CM were significantly less than those resulting from the same concentration of ionic CM. CONCLUSIONS: Nonionic CM is less nephrotoxic than ionic CM with regard to gluconeogenesis and PAH accumulation in rat renal slices. These differences in nephrotoxic effect between ionic and nonionic CM may in part be attributable to differences in osmotic pressure.

Animals↗

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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