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Y Ohtawara

Publications and source records attributed to Y Ohtawara.

At least 19 recordsLinked to original sources
PubMed1998

Telomerase activity as an indicator of potentially malignant adrenal tumors.

BACKGROUND: Telomerase is an enzyme that adds repeated telomere sequences to the ends of chromosome arms. It helps maintain both the length of telomere and infinite cell proliferation. In recent years, telomerase activity has been considered an important characteristic that differentiates between normal and cancerous cells. Because the authors often encountered difficulties in distinguishing between benign and malignant adrenal tumors, they investigated whether the expression of telomerase activity could distinguish potentially malignant adrenal tumors. METHODS: The authors examined telomerase activity in 48 samples of adrenal tumor tissue and 27 samples of adjacent normal adrenal tissue. All samples were obtained from 48 patients who underwent surgery at Hamamatsu University Hospital in Hamamatsu, Japan. Based on the clinical and postoperative pathologic examinations, 45 samples were diagnosed as benign and 3 were diagnosed as malignant. Telomerase activity was examined using a telomerase repeat amplification protocol (TRAP) assay. RESULTS: Of the 48 adrenal tumor samples, 7 (14.6%) had telomerase activity. All adjacent normal adrenal tissues were negative for telomerase activity. Of the telomerase positive samples, two were clinically known adrenocortical carcinoma, and another was metastatic adrenal tumor from lung carcinoma. Four other telomerase positive samples were diagnosed as benign after clinical and initial pathologic examinations. However, two of the patients from whom these samples were taken developed metastatic lesions after adrenalectomy. CONCLUSIONS: A telomerase assay of adrenal tumors may help predict their malignant potential.

Adrenal Gland Neoplasms↗
PubMed1997

Morphological analysis of renal cell culture models of calcium phosphate stone formation.

Cell culture models of calcium phosphate renal stone formation were established using the MDCK cell line. Renal microliths were detected within pseudocysts in three-dimensional soft agar cultures, and were also observed in the basal region of cells lining the cell sheet, and immediately beneath domes or blisters in monolayers and collagen gel cultures. Light and scanning electron microscopy indicated that these microliths had a similar lamellated and spherical appearance to those in humans. These microliths were first detected microscopically after 21 days of culture, and were found to be composed of calcium phosphate by X-ray and micro-infrared spectroscopic analyses. These culture models may provide a powerful new tool to study the pathogenesis of renal stone diseases and/or calcium phosphate stone formation in humans and animals.

Animals↗
PubMed1996

Expression of structure-specific recognition protein mRNA in fetal kidney and Fe-nitrilotriacetate-induced renal carcinoma in the rat.

Specific expression of the structure-specific recognition protein (SSRP) gene was investigated in rat fetal, adult, and tumor tissues using a 2.0-kb partial sequence of rat SSRP cDNA isolated from a cDNA library of rat renal cell carcinoma. The results revealed that it was rather specifically expressed in rat fetal kidney and renal cell carcinoma induced by Fenitrilotriacetate, but not in adult kidney, when various organs were tested by Northern blot analysis. In situ hybridization further demonstrated that it was located in the neoplastic cells of renal cell carcinoma and in the epithelial cells of fetal kidney but undetectable in any cells of normal adult kidney. These observations seem to imply the involvement of SSRP gene, which is believed to recognize structural alterations of DNA, in kidney development and carcinogenesis of certain types of kidney cancer.

Animals↗
PubMed1996

Microlith formation in vitro by Madin Darby canine kidney (MDCK) cells.

BACKGROUND: The mechanism of renal stone genesis as well as the location of stone crystal formation in the kidney remains unclear. Possible sites of stone generation are either in the tubular lumen or tubular cell. METHODS: We cultured Madin Darby canine kidney (MDCK), LLC-PK1 and Magen Krebs Niigata-28 (MKN-28) cells in DMEM + 10% FBS medium in a well without passage for 30 days. RESULTS: MDCK cells produced microliths at the basolateral side but not on the lumen side of these cells. The other two cell lines did not form microliths. CONCLUSION: Our data show that microlith formation is a characteristic of MDCK cells and that biological mineralization of MDCK cells may serve as a human urolithiasis model in vitro. The findings support a significant role of the renal distal convoluted tubule and collecting ducts in the in vitro generation of urinary stones.

Alkaline Phosphatase↗
PubMed1996

[Laparoscopic adrenalectomy for Cushing's syndrome: a study of comparisons between laparoscopic and open adrenalectomy, and laparoscopic adrenalectomy for differing adrenal tumors].

In order to evaluate the utility of laparoscopic adrenalectomy for Cushing's syndrome, the results of 6 laparoscopic adrenalectomies for Cushing's syndrome were compared with those of 34 other laparoscopic adrenalectomies, consisting of 7 pre-Cushing's syndromes, 13 primary aldosteronisms, and 14 non-functioning adrenal tumors. The results were also compared with 5 open adrenalectomies for Cushing's syndrome. The results of the laparoscopic adrenalectomies for Cushing's syndrome were as follows: the mean operating time was 216 +/- 46 min, and the mean estimated blood loss was 180 +/- 194 ml. From the third patient, an ultrasonic surgical system was used and the estimated blood loss decreased significantly. The ultrasonic surgical system, together with a more experienced surgical technique, also cut down the operating times. During surgical intervention, 2 complications occurred; a hemorrhage of more than 500 ml in one patient, and splenic injury in another, which was treated by compression. Postoperative complications occurred in 2 patients; paralytic ileus in one, and abdominal pain due to the pneumoperitoneum in the other. All patients except 2 patients with vertebral fracture began oral intake and ambulation 1 to 4 days postoperatively, and resumed normal daily activity on postoperative day 5 to 7. Compared with the laparoscopic adrenalectomies for the other adrenal tumors, the operating time and estimated blood loss in the Cushing's syndrome patients was not substantially different, though postoperative recovery was slightly longer. When compared with the open adrenalectomies, the operating time was longer, but the postoperative recovery period was significantly shorter. We conclude that with careful surgical intervention, experience of technique, and the introduction of proper equipment, a laparoscopic adrenalectomy for Cushing's syndrome can be performed as less-invasively as a laparoscopic adrenalectomy is for the other adrenal tumors. Furthermore, our findings suggest that laparoscopic adrenalectomy for Cushing's syndrome is likelier to have better postoperative results than conventional procedures, including a more rapid recovery to normal daily activity.

Adrenal Gland Neoplasms↗
PubMed1995

[Adrenalectomy for nonfunctioning adrenal tumors--comparison between open and laparoscopic surgery, and indication for operation].

Since 1977, we have operated on 18 nonfunctioning adrenal tumors. The pathological diagnosis included seven adrenocortical adenomas, three adrenocortical hypeplasias, three ganglioneuromas two adrenal cysts, two myelolipomas and one metastatic cancer. We successfully performed laparoscopic adrenalectomy in 11 of these patients and open surgery in the other 7 patients. In the patients undergoing laparoscopic adrenalectomy, post-operative recovery (fist oral intake, first ambulation, and total convalescence) was remarkably rapid. The indication of adrenalectomy for nonfunctioning adrenal tumors is controversial, but we can not exclude the possibility of malignancy even in small tumors. Therefore, because of the minimally invasive nature of laparoscopic surgery, the indications for operating on nonfunctioning adrenal tumors will be widened by introducing laparoscopic adrenalectomy.

Adrenal Gland Neoplasms↗
PubMed1994

Isolation of complementary DNA encoding K-cadherin, a novel rat cadherin preferentially expressed in fetal kidney and kidney carcinoma.

Complementary DNA for a novel member of the cadherin family, designated K-cadherin, was isolated from a rat renal cell carcinoma complementary DNA library by screening it with a short complementary DNA probe which was initially obtained from the RNA of day 16 fetal Wistar rat stomach mucosa by the polymerase chain reaction. The deduced primary structure of K-cadherin is 789 amino acid residues, which contain five internal repeats in its extracellular domain, a single putative transmembrane domain, and a cytoplasmic tail characteristic of those of classic type cadherins. K-cadherin exhibits low homology with mature proteins of mouse N- (38%), E- (35%), and P-cadherin (32%), and high homology with a partially identified human cadherin-6 protein (95%) at the amino acid level. Northern blot analysis revealed a high level of expression of K-cadherin mRNA in fetal rat kidney and brain, and rat kidney carcinoma with two major transcripts, 4.1 and 8.0 kilobases in size, whereas there was very weak or no expression in any organ of adult rats. The level of K-cadherin expression was also elevated in some human kidney cancer tissues. In the developing kidney, in situ hybridization showed localization of K-cadherin mRNA in the nephroblastic epithelial cells of comma bodies coinciding with those in the process of polarization during glomeruloneogenesis. These results demonstrate that K-cadherin must have important functions in both the process of kidney development and tumorigenesis of some types of kidney cancer.

Amino Acid Sequence↗
PubMed1994

Laparoscopy-assisted radical nephrectomy without pneumoperitoneum.

A small renal cell carcinoma of the right kidney was completely removed from a 59-year-old women by laparoscopic radical nephrectomy without requiring a pneumoperitoneum. A 5-cm midline laparotomy incision was made and 3 small retractors were used for suspending the abdominal wall. Under laparoscopic observation, we safely positioned three trocars. The kidney was then removed en bloc together with the adrenal gland, perinephric fat and Gerota's fascia. The resected mass was enclosed in an entrapment sac and removed via the 5-cm abdominal incision without morcellation of the tissues. Three trocars could be positioned safely under direct observation and there were no adverse hemodynamic or ventilatory effects because the operation was performed without intraperitoneal carbon dioxide insufflation. There were no significant operative or postoperative complications. This procedure appears to be advantageous for the treatment of small renal cell carcinomas.

Carcinoma, Renal Cell↗
PubMed1993

[An incidentally found asymptomatic pheochromocytoma: a case report--successful removal laparoscopic adrenalectomy].

A 31-year-old male was admitted to our hospital for further examination of a right adrenal mass, which was incidentally discovered by abdominal ultra-sonography in another hospital. The adrenaline and noradrenaline in the plasma and the adrenaline and VMA in the urine were slightly elevated, and catecholamines in the blood from the right adrenal vein were markedly increased. Glucose tolerance test showed a borderline case. Otherwise, there was no clinical sign. Asymptomatic pheochromocytoma originating from the right adrenal gland was suspected in the preoperative diagnosis. Laparoscopic right adrenalectomy was performed. Although the blood pressure was stable preoperatively, paroxysmal hypertension was observed during the tumor manipulation. Blood pressure was well controlled during the operation with ATP, nitroglycerin and phentolamine. Blood loss was less than 150ml, and there was no surgical complication. The resected tumor specimen was 32[28[33mm in size, weighed 14g, and histological examination showed typical pheochromocytoma. The post-operative course was unremarkable and glucose tolerance test was normalized after the operation. This is the first case of the successful removal of pheochromocytoma using the laparoscopic procedure.

Adrenal Gland Neoplasms↗
PubMed1993

Laparoscopic nephrectomy for atrophic kidney associated with ectopic ureter in a child.

An atrophic right kidney located in the pelvic cavity associated with an ectopic ureter was completely removed from a 4-year-old girl by laparoscopic surgery. There were no serious complications during the operation or the postoperative period. The light shining from the tip of a fine fiberscope inserted into the ureter was used to delineate this structure during laparoscopic surgery.

Atrophy↗
PubMed1993

[Experience of laparoscopic pelvic lymphadenectomy in 10 patients].

From November 1991 through January 1993, we performed laparoscopic lymphadenectomy on 10 patients. These patients were aged 54 to 77 years. All laparoscopic procedures were performed under general anesthesia. We dissected obturator lymph nodes on bilateral side. Total operation time ranged from 127 to 325 minutes. We could excise 3 to 9 lymph nodes on right side and 0 to 10 lymph nodes on left side. Blood loss was 180 ml in one patient, but minimal in the remaining 9 patients. Ureteral injury occurred during laparoscopic procedure in one patient. This injury could be managed with laparoscopic and cystoscopic procedure. Postoperatively complications were observed in 5 procedures, which consisted of subcutaneous emphysema in 2 procedures, fever (over 38 degrees C) in 2, shoulder and arm pain in 1, ileus in 1. The patient with ileus complained of abdominal fullness but he was able to ingest. All patients resumed their preoperative activity by postoperative day 3 to 5. We believe that this procedure was safe and useful for decision making in the management of our patients. We need further study on indications and techniques for this procedure.

Aged↗
PubMed1991

[Cyclosporine induced nephrotoxicity and juxtaglomerular apparatus in mice].

To elucidate the relationship between Cyclosporine (Cs) induced nephrotoxicity and juxtaglomerular (JG) apparatus, we carried out biochemical and morphological experiments using mice. Adult male ICR strain mice weighing about 40 g were used. The mice were divided into 2 groups: the Cs group (Cs 50 mg/kg/day was orally given for 14 consecutive days) and the control group (olive oil for 14 days). Urine was stored for 24 hours on the day 0, 7 and 14 and urine volume and concentrations of urinary creatinine (u-Cr) and urinary potassium (u-K) were measured in each group. All the mice were sacrificed and examined on the 15th day. Concentrations of serum creatinine (s-Cr), serum potassium (s-K), plasma renin activity (PRA), plasma aldosterone (Ald) were noted in each group. The kidneys were also examined histologically with light and electron microscopes. The Cs group showed significant increases of s-K, PRA and Ald and a significant decrease of creatinine clearance compared with the control group. Histologically, the Cs group demonstrated focal vacuolar changes in the proximal tubular cells and an increase in the number of granules in the JG cells. Each granule of the Cs group was larger than that of the control group. Cs certainly stimulates the renin-angiotensin-aldosterone system and causes consequently a secondary aldosteronism.

Animals↗
PubMed1991

[Cyclosporine induced nephrotoxicity and renal blood flow].

To elucidate the relationship between cyclosporine (Cs) nephrotoxicity and renal blood flow (RBF), we carried our experiments using rats. Adult male Wistar strain rats each weighing about 100 g were used. Rats were divided into 2 groups; the Cs group (Cs 50 mg/kg/day was intraperitoneally given for 10 consecutive days) and the control group (normal saline solution for 10 consecutive days). The renal cortical blood flow was measured in each group by electrolytic hydrogen gas clearance method. We also carried out renal angiography with barium sulfate (BaSO4). Then we measured blood vessel area/renal sagittal section area ratio and the diameter of interlobar arteries. The Cs group showed a significant decrease of renal cortical blood flow compared with the control group. On the other hand there was no significant change in renal angiogram. In conclusion, Cs decreased renal cortical blood flow. We suppose that vascular resistance increased following afferent arteriolopathy caused by Cs administration.

Animals↗
PubMed1990

Treatment of staghorn calculi by fiberoptic transurethral nephrolithotripsy.

We treated 34 patients with staghorn calculi by fiberoptic transurethral nephrolithotripsy with a flexible nephroureteroscope and an electrohydraulic lithotriptor. Of the 34 patients 30 (88.2%) were treated successfully. There were 17 patients each with complete and partial staghorn calculi. There was no difference in the success ratio and the rate of residual fragments between the 2 groups. However, post-procedural fever, sepsis and extrapelvic extravasation were observed more frequently in patients with complete than with partial staghorn calculi. Countermeasures to avoid complications must be developed in the future. However, we believe that fiberoptic transurethral nephrolithotripsy is a safe and effective treatment for staghorn calculi. This procedure also should be recommended, as well as the combination of percutaneous nephrolithotomy and extracorporeal shock wave lithotripsy.

Adult↗