Toshiki Tsutsui

Does Gadolinium-diethylene triamine pentaacetic acid enhanced MRI of kidney represent tissue concentration of contrast media in the kidney? In vivo and in vitro study

Although Gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) has been used as a contrast material in magnetic resonance imaging (MRI), it is known that contrast enhancement effect is not uniform if the concentration of Gd-DTPA increases beyond some levels. In this study, to evaluate the proper pulse sequences for dynamic MRI in the human kidney, the concentration of Gd-DTPA was quantitatively measured by inductively coupled plasma (ICP) emission spectrometry in human biological samples after administration of Gd-DTPA. The signal intensity of MRI in the solutions of several concentrations of Gd-DTPA was measured. The results were that in using a low magnetic field apparatus, signal intensity linearly correlated with the concentration of Gd-DTPA between 0 and 2.0 mumol/g under saturation recovery sequences (flip angle = 60 degrees or 90 degrees). Using a high magnetic field apparatus, signal intensity linearly correlated with the concentration of Gd-DTPA between 0 and 2.0 or 3.0 mumol/g under spin-echo or gradient-echo sequences. Gd-DTPA concentration of the renal cortex ranged from 0.132 to 0.152 mumol/g tissue at 5 min after IV injection of Gd-DTPA 0.05 mmol/kg body weight in six patients with adrenal tumor or renal cell cancer, and one patient with both urinary bladder cancer and prostatic cancer. Six of the patients showed normal renal function and the other had renal insufficiency (GFR = 25 ml/min/1.48 m2).(ABSTRACT TRUNCATED AT 250 WORDS)

Value of dimercaptosuccinic acid single photon emission computed tomography and magnetic resonance imaging in detecting renal injury in pediatric patients with vesicoureteral reflux : comparison with dimercaptosuccinic acid planar scintigraphy and intravenous pyelography

The value of 99mTc-dimercaptosuccinic acid (DMSA) planar renal scintigraphy, DMSA single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) in the assessment of renal injury related to vesicoureteral reflux (VUR) was examined in 60 kidneys of 32 pediatric patients (28 bilateral, 4 unilateral) with primary VUR. The results were: (1) detection of minor renal lesions was best with MRI, then DMSA-planar and DMSA-SPECT, and (2) in comparing the positive rate, DMSA-SPECT (85%) and MRI (83.3%) were superior to intravenous pyelography (55%) and DMSA-planar scintigraphy (65%). These results suggest that DMSA-SPECT or MRI may be more sensitive than DMSA-planar scintigraphy and intravenous pyelography in detecting renal injury related to VUR in pediatric patients.

Changes in urinary excretion of endothelin-1-like immunoreactivity before and after unilateral nephrectomy in humans. Comparison with other urinary parameters and unilateral adrenalectomy.

To assess the value of endothelin-1 (ET-1) as a parameter of renal functional overload and the process of hyperfiltration, urinary excretion of ET-1-like immunoreactivity (U-ET-1) and urinary excretion of other parameters [beta 2-microglobulin (beta 2-MG), N-acetyl-beta-D-glucosaminidase (NAG), albumin (Alb) and 24-hour creatinine clearance (Ccr24)] were measured before, 1, 2 and 7 days after unilateral nephrectomy in 15 patients with unilateral renal lesions (renal cell cancer, renal pelvic cancer, ureteral cancer and renal tuberculosis) and after unilateral adrenalectomy in 5 patients with adrenal lesions. In the nephrectomy group (NX), Ccr24 significantly decreased at 1 and 2 days after the operation, but the other 4 parameters significantly increased after the operation as compared to preoperative values. In the adrenalectomy group (ADX), neither Ccr24 nor ET-1/Cr showed any change after the operation, but the other 3 parameters (beta 2-MG/Cr, NAG/Cr and Alb/Cr) significantly increased. Comparing the NX and ADX groups, both ET-1/Cr and beta 2-MG/Cr in NX were significantly higher than in ADX after the operation. On the other hand, neither NAG/Cr nor Alb/Cr in NX differed from values in ADX. Comparing ET-1/Cr and other parameters, only beta 2-MG showed a positive significant correlation. These results suggest that U-ET-1 may be an indicator of functional overload of the kidney.

Low‐grade renal epithelial tumor originating from the distal nephron

In the February 2004 issue of International Journal of Urology , Hara et al . reported a case of a low-grade renal epithelial tumor originating from the distal nephron. 1 I read their article with great interest. Regarding this neoplasm, two large studies have been reported in 2002. 2,3 Rakozy et al . reported multiple losses of chromosomes 1, 4, 6, 8, 9, 13, 14, 15 and 22 in low-grade tubularmucinous renal neoplasm (LGTMRN) by using comparative genomic hybridization. 3 Subsequently, this neoplasm has been categorized as mucinous tubular and spindle cell carcinoma (MTSCC), according to the World Health Organization classification of tumors. 4

Value of Urinary Endothelin-1 in Patients with Primary Vesicoureteral Reflux

By using a radioimmunoassay specific for endothelin-1 (ET-1), we measured urinary excretion of ET-1-like immunoreactivity (LI) in 63 spot urine samples of 48 patients with primary vesicoureteral reflux (VUR). And also, urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), beta 2-microglobulin (beta-2-MG), microalbumin (Alb) and creatinine (Cr) were measured. There was no significant correlation in any of the pairs ET-1 and NAG, ET-1 and beta 2-MG, and ET-1 and Alb. Comparing the grade of reflux according to the International Classification with urinary ET-1, urinary ET-1/Cr levels in patients with grade 2, 3 and 4 VUR were higher than normal, and the ratio of more than normal urinary ET-1/Cr increased in proportion to the grade of reflux, but it conversely decreased in grade 5. In conclusion, urinary ET-1 may be an indicator of renal tubular injury in patients with primary VUR, and its meaning may be different from conventional urinary parameters.

α1- and α2-Adrenoceptors in BPH

The dynamic obstruction of the bladder outlet secondary to benign prostatic hyperplasia (BPH), and the contractile properties of the human prostate are mediated primarily by α₁-adrenoceptors. There are now at least three subtypes (A, B, and D) of α₁-adrenoceptors, and recent work revealed that α_1A-adrenoceptor and α_1B-adrenoceptor may have a prime role for prostatic obstruction, and contraction of artery, respectively. Very recently, the presence of a low affinity α₁-adrenoceptor for prazosin, named α_1L, in the human BPH tissue has been determined. Because the DNA sequence of α_1L-adrenoceptor has not yet been cloned, the α_1L-adrenoceptor may be another form of the α_1A-adrenoceptor, or another pharmacologically distinct α₁-adrenoceptor which mediates the norepinephrine-induced contraction of the prostatic smooth muscle. Furthermore, the contribution of α₁-adrenoceptors in the prostate to symptoms (not only obstructive, but irritative symptoms) which are elicited by prostatic obstruction remains to be determined.

Changes in urinary excretion of endothelin-1-like immunoreactivity in patients with testicular cancer receiving high-dose cisplatin therapy.

To assess the value of endothelin-1 (ET-1) in estimating renal injury in patients receiving high doses of cisplatin, urinary excretion of ET-1-like immunoreactivity (U-ET-1), beta 2-microglobulin (U-beta 2-MG), and N-acetyl-beta-d-glucosaminidase (NAG) were measured before, 1 week after, and 2 weeks after the administration of cisplatin in eight patients with testicular cancer (mean age, 33.3 years). Levels of U-ET-1/creatinine (Cr) during and 1 week after cisplatin treatment were significantly higher than before cisplatin treatment. There were no differences in U-ET-1/Cr levels during, 1 week after, and 2 weeks after cisplatin treatment. The level of U-beta 2-MG/Cr during cisplatin treatment was significantly higher than levels before, 1 week after, and 2 weeks after treatment. However, there were no differences in U-beta 2-MG/Cr levels before, 1 week after, and 2 weeks after cisplatin treatment. The level of U-NAG/Cr during cisplatin treatment was higher than levels before, 1 week after, and 2 weeks after treatment; U-NAG/Cr during cisplatin treatment was higher than levels before, 1 week after, and 2 weeks after treatment; U-NAG/Cr gradually decreased after cisplatin treatment. Among the three parameters, only U-ET-1/Cr maintained a higher level after cisplatin treatment. The U-beta 2-MG/Cr level returned most rapidly to normal after cisplatin treatment. Although U-ET-1/Cr did not show any significant correlation with U-NAG/Cr (r = 0.282, P = NS), it showed a significant correlation with U-beta 2-MG/Cr (r = 0.454, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical studies of caveolin-3 in germ cell tumors of the testis.

Background/Aim: Caveolin, which is a major constructive component of the caveolar membranes, plays a key role in transcytosis of molecules into cells and regulation of several signal transductions. Caveolin has three isoforms, and recent studies suggest that in some malignant tumors an alteration of caveolin-1 expression correlates with oncogenetic changes. Caveolins have been reported to be negative regulators of inducible nitric oxide synthase (iNOS) which can provoke an antitumor response via infiltrating immune cells. The aim of this study was to examine the expressions of caveolin-1 and caveolin-3 (which is a caveolin-1 homologue localized predominantly in muscle tissue) in testicular cancer. Methods: We evaluated the expressions of caveolin-1, caveolin-3, and iNOS in 16 seminoma and 10 non-seminoma testicular cancer specimens as well as normal testicular tissue, using a streptavidin-biotin bridge technique on cryostat sections. The expression of caveolin-3 was confirmed by slot-blot analysis. Tumor-infiltrating immune cells were also studied immunohistochemically, and the correlation between the number of immune cells and caveolin-3 concentrations was calculated. Results: Immunohistochemistry revealed that caveolin-3, but not caveolin-1, was frequently expressed in seminomas (12 positive out of 16 specimens) without positive staining in their normal counterparts or in nonseminomatous germ cell tumors, except for muscle components in the teratoma. iNOS was not expressed in any tissues examined. Samples with high levels of caveolin-3 tended to have higher degrees of tumor-infiltrating immune cells, although this finding was not statistically significant. Conclusion: This is the first report demonstrating the involvement of caveolin-3 in germ cell tumors.

Endothelin receptors in the human urinary bladder are different from those in the human ureter

Human urinary bladders from ten patients undergoing total cystectomy for bladder cancer and human ureters from ten patients undergoing radical nephrectomy for renal cell cancer were used. Strips (10 mm long, 1-2 mm wide) from the dome of urinary bladder and spirally cut strips (10 mm long, 2-4 mm wide) of ureter freed from mucosa were used. Informed consent was obtained from each patient before operation. Isometric contraction experiments were performed under 0.5 g tension in 10-ml organ baths containing modified KrebsHenseleit solution using indomethacin (1 gm). After 1 h equilibration and a reference contraction by 116.9 mM KC1, subsequent reponses were expressed as a percentage of the reference contractions obtained following completion of the experiment. Cumulative concentration-response curves to endothelin-1 (ET1, 0.1-0.1 gM) and sarafotoxin

Evaluation of upper urinary tract dynamics by diuresis renography in patients receiving urinary reservoir operation : comparison of full and empty reservoir

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