Takaki Mizusawa

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.

Primitive neuroectodermal tumor of the adrenal gland

Abstract  We report a rare case of primitive neuroectodermal tumor arising from adrenal gland in adulthood, diagnosed preoperatively as having non‐functional adrenocortical adenoma. Laparoscopic adrenalectomy was performed. Immunohistological examination revealed the definite diagnosis as primitive neuroectodermal tumor of the adrenal gland. Although primitive neuroectodermal tumor is a highly malignant neoplasm, there is no evidence of local recurrence and distant metastasis 16 months after surgery.

The role of naftopidil in the management of benign prostatic hyperplasia.

Naftopidil, which to a certain extent shows an affinity to α1D-adrenoceptor subtype in addition to a high affinity to α1A-adrenoceptor, has been used for the treatment of benign prostatic obstruction and benign prostatic hyperplasia (BPH) associated lower urinary tract symptoms (LUTS). The aim of the present review is to systematically refer to the published studies on this unique agent for BPH. Based on a randomized prazosin-controlled study and another double-blind placebo-controlled study, which verified the dose-dependent effects of naftopidil, the Japanese Ministry of Health, Labor and Welfare approved naftopidil for treating men with BPH in 1996. Several tamsulosin-controlled studies have suggested treatment effects of naftopidil similar to those of tamsulosin and potentially higher efficacy for alleviating storage symptoms by naftopidil. Although well-designed, randomized studies are warranted to confirm the long-term outcomes and effector/target of naftopidil, the α1A-antagonist naftopidil, which also blocks α1D-adrenoceptor, improves voiding symptoms, and may also be useful for the management of men with storage symptoms represented by nocturia, retrieving their quality of life impaired by BPH-associated LUTS.

Alpha-1 adrenoceptor subtypes (high, low) in human benign prostatic hypertrophy tissue according to the affinities for prazosin

A novel classification of α‐1 adrenoceptor subtypes (High, Low) was applied to human benign prostatic hypertrophy (BPH)tissue.

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.

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)

Clinical Feature of Men Who Benefit from Dose Escalation of Naftopidil for Lower Urinary Tract Symptoms: A Prospective Study

Objectives. To examine the feature of men who benefit from dose escalation of naftopidil for lower urinary tract symptoms (LUTSs). Methods. Based on the IPSS, men reporting LUTS were prospectively studied using 50 mg/day of naftopidil for the first 4 weeks; satisfied patients continued its 50 mg/day (n = 11), and those reporting unsatisfactory improvement received its 75 mg/day (n = 35) for the next 4 weeks. Results. The 75 mg group showed improvement in the total IPSS and QOL score in a dose-dependent manner (at 4 weeks: P < .001, at 4 weeks versus 8 weeks: P < .05). In the 50 mg group, both scores reduced at 4 weeks, thereafter unchanged. The baseline slow stream score alone was higher in the 75 mg group (P = .013). The rate of change in the QOL score during the initial 4 weeks (ΔQOL) and Δnocturia was smaller in the 75 mg group (P < .05). Conclusions. Men with high slow stream score and unsatisfactory improvement in nocturia may benefit from dose escalation of naftopidil.

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