Shigeo Kaneko

Differential brain processing of audiovisual sexual stimuli in men: comparative positron emission tomography study of the initiation and maintenance of penile erection during sexual arousal.

The human male psychosexual cycle consists of four phases: excitation, plateau, orgasm, and resolution. Identification of the specific neural substrates of each phase may provide information regarding the brains pathophysiology of sexual dysfunction. We previously analyzed regional cerebral blood flow (rCBF) with H(2)15O-positron emission tomography (PET) during the excitation phase (initiation of penile erection) induced by audiovisual sexual stimuli (AVSS) and identified activation of the cerebellar vermis, the bilateral extrastriate cortex, and right orbitofrontal cortex, suggesting a role of cognition/emotion in the excitement phase. In the present study, we analyzed rCBF of the same six healthy volunteers during the plateau phase (maintenance of penile erection) induced by AVSS and compared the results with those of the excitation phase. Penile rigidity was monitored in real time with RigiScan Plus during PET scanning. Images were analyzed by statistical parametric mapping (SPM) software, and rCBF in the amygdala, hypothalamus, anterior cingulate, and insula was measured. During the plateau phase, primary subcortical activation was noted in the right ventral putamen, indicating motivational factors in the sexual response via the limbic reward circuit. A significant increase in rCBF in the left hypothalamus was also observed during the plateau phase. The right anterior cingulate and left insula were specifically activated during the excitation phase but not during the plateau phase. These results indicate a significant role of the ventral putamen and the hypothalamus in the plateau phase and confirm that paralimbic and limbic components of the human brain differentially coordinate the sexual response in a psychosexual phase-dependent manner.

A Study Of Micturition Inducing Sites In The Periaqueductal Gray Of The Mesencephalon

PURPOSE The mesencephalon, especially the periaqueductal gray, is believed to integrate specific movement patterns of the somatic and autonomic nervous system, including those of vocalization, defensive behaviors and others. Fiber communications exist between the periaqueductal gray and the pontine micturition center, and many nerve fibers ascending from the sacral spinal cord project to the periaqueductal gray. We examined whether the mesencephalon is involved in micturition function using microstimulation and a neurotracer. MATERIALS AND METHODS We decerebrated 28 adult cats under general anesthesia. An electrode that can be used for microinjection was positioned in stereotaxic fashion in the mesencephalon and pons. Subsequently electrical stimulation and chemical stimulation with DL-homocysteine acid were applied to search for micturition inducing sites. Blood pressure and respiration were monitored simultaneously. We also performed electrical microstimulation of pontine micturition center. The neurotracer 5% Fluoro-Gold (Denver, Colorado) was injected into these sites to identify neural pathways between the mesencephalon and pons. The brainstem was removed after 10 hours and the mesencephalon was examined by fluorescence microscopy. RESULTS Bladder contraction was provoked by electrical and chemical stimulation applied mainly at the ventrolateral side of the periaqueductal gray. Blood pressure increased simultaneously with bladder contraction after periaqueductal gray stimulation. Neurotracer injected into the pontine micturition center was found mainly on the ventrolateral side of the periaqueductal gray, in agreement with the sites where micturition was provoked by microstimulation. CONCLUSIONS Nerve cells on the ventrolateral side of the periaqueductal gray have neural communications with the pontine micturition center bilaterally and they regulate micturition.

Immunohistochemical Expression of Metallothionein in Human Bladder Cancer: Correlation With Histopathological Parameters And Patient Survival

PURPOSE We assessed metallothionein expression and its patterns of distribution as possible prognostic variables in bladder cancer with regard to histopathological parameters. MATERIALS AND METHODS We stained 91 formalin fixed, paraffin embedded tissue specimens of bladder cancer from 91 patients with no history of treatment using an immunohistochemical technique for metallothionein. Relationships between immunoreactivity for metallothionein and histopathological parameters were examined. In addition, these parameters, including metallothionein, were evaluated as potential prognostic markers. RESULTS Metallothionein was detected in 33 of 91 bladder cancers (36.3%). There were significant relationships of metallothionein expression with high grade, high stage and nonpapillary growth pattern tumors. There was no specific correlation of metallothionein expression with the interval to intravesical recurrence. In the 31 patients who underwent radical cystectomy a significant relationship between metallothionein immunoreactivity and cancer specific survival was found. CONCLUSIONS Our findings suggest that a close correlation exists of metallothionein expression with histopathological parameters and metallothionein expression can be a useful prognostic variable for bladder cancer.

Comparative study of novel endoluminal ultrasonography and conventional transurethral ultrasonography in staging of bladder cancer

Abstract  Background:  Recent advances in ultrasonic techniques have improved the image quality and diagnostic accuracy for staging of bladder cancer. The aim of this study was to assess the feasibility and usefulness of endoluminal ultrasonography (ELUS) in staging of bladder cancer, and to compare them with those of conventional transurethral ultrasonography (TUUS).

Clinical Applicability of a New Tactile Sensor for Evaluating Rigidity of the Penis: A Comparative Study with Rigiscan

Background: A new tactile sensor was developed for detecting hardness of living tissue by Omata et al. in 1992. This paper reports applicability of the sensor for evaluation of penile rigidity.

Cerebral control of bladder storage in patients with detrusor overactivity

ObjectiveTo identify the brain areas that control bladder storage by technetium-99m hexamethylpropyleneamine oxime single-photon emission computed tomography (SPECT) with the Neurological Statistical Image Analysis software (NEUROSTAT) in patients with detrusor overactivity (DO). MethodsSPECT scans were performed on 19 patients with DO. Eight patients with normal detrusor function, who had some storage symptoms of the lower urinary tract as the patients with DO, also had a SPECT scan, as controls. All the patients were male and right handed, and were scanned twice under two conditions: resting state and urine withholding state. NEUROSTAT was adopted to analyze the difference in brain--blood perfusion between groups and states. The results were displayed on Z score images at a significance threshold of P value of less than 0.05 with correction for multiple comparisons. ResultsNo region reached the significant threshold in comparison with patients with DO and normal detrusor function in resting state. Significant increases in tracer activity in the right inferior frontal gyrus and the right middle temporal gyrus during urine withholding state as compared with resting state in patients with normal detrusor function were observed. Among the regions, the right inferior frontal gyrus was distinctly prominent at both Z score and the extent. The regions that were significantly activated in patients with normal detrusor function did not reach a significant threshold during urine withholding in patients with DO. ConclusionThe study indicated that the right inferior frontal gyrus and the right middle temporal gyrus, especially the right inferior frontal gyrus, played a role in the cerebral control of bladder storage, inhibiting the contraction of detrusor in urine storage.

Secondary Mucinous Adenocarcinoma of the Prostate in a Patient with Ulcerative Colitis

Herein we report a rare case of prostatic invasion of rectal carcinoma in a patient with ulcerative colitis. Malignant transformation is a well-known complication of long-standing ulcerative colitis. Mucinous adenocarcinoma, with positive carcinoembryonic antigen and negative prostate-specific antigen, strongly suggested the rectal origin of the tumor.

Ultrasonographic study on kidneys in patients with acute renal failure

Ultrasonotomograms of 22 kidneys were obtained in 11 patients with renal-acute renal failure (renal-ARF). The underlying diseases of renal-ARF were acute tubular necrosis in 8 patients and acute on-set chronic glomerulonephritis in 3 patients. They were treated by hemodialysis in 10 patients and intermittent peritoneal dialysis in 1 patient. Ultrasonic measurement of the size of kidneys revealed that the thickness (anterior-posterior diameter) and the ratio of thickness to length (T/L) were greater in patients with ARF than in those with chronic renal failure and normal renal function. The patients with a low value of T/L (under 0.60) had a significantly greater urine volume than those with high a value of T/L (0.60 or more). The sonographic features of renal-ARF kidneys were marked increase in parenchymal echogenicity and appearance of hypoechoic swollen renal pyramids with sharpness of the corticomedullary border. In the course of ARF, these sonographic changes gradually disappeared when the patients had recovered from ARF. However, the prognosis was poor in patients with severer sonographic findings. We believe that repeated ultrasonic examination of the kidneys in patients with renal-ARF is useful for not only differential diagnosis of post-renal urinary obstruction but evaluating the course of ARF.

Optimization of the uptake method for estimating renal clearance of 99mTc mercaptoacetyltriglycine.

ObjectiveTo improve the estimation of 99mTc mercaptoacetyltriglycine clearance in the renal uptake method by optimizing the conditions of renal depth, background, threshold for renal boundary determination, and time interval for integrating renal counts. MethodsDynamic renal imaging was performed in 232 patients with dual energy window acquisition (main, 140±14 keV; sub, 122.5±3.5 keV). For drawing renal regions of interest (ROIs), cut-off methods with 50% and 70% of the highest renal pixel counts were used. For drawing the backgrounds, circumferential and lateral-inferior quadrant peri-renal ROIs were used. For setting the time interval, periods of 1–2, 1–2.5, 1.5–2.5, 1.5–3 and 2–3 min post-injection were used. For determining renal depth, three methods of a theoretical exponential function using scatter fraction, Tønnesens formula, and linear combination of scatter fraction and Tønnesens formula were used. The scatter fraction was calculated using the counts in renal ROIs in the two energy windows. Using every combination of these conditions, renal uptake was calculated. As a reference, one-sample clearance was calculated from a blood sample taken at 30 min post-injection following Bubecks formula. According to the methods for estimating renal depth, three non-linear regression models were derived to convert renal uptake to clearance. Using one-sample clearance and integrated renal counts as dependent and independent variables, data were fitted to the models to determine the necessary constants. The correlations between the model estimated clearances and one-sample clearance were investigated. ResultsOne-sample clearance ranged from 11 to 404 ml·min−1 per 1.73 m2. More than half of the regression using renal depth determined by the scatter fraction alone failed to converge. Among the successfully converged regressions, all model estimated clearances showed significant correlations (P<0.01) with one-sample clearance. The best correlation was observed in the model using renal depth determined by the combination of scatter fraction and Tønnesens formulas, renal ROIs by 50% cut-off, lateral-inferior background and time interval of 2–3 min (r=0.898, P<0.001). ConclusionThe renal uptake method for estimating the clearance of mercaptoacetyltriglycine can be improved by the processing conditions proposed here.

EARLY STAGE OF UROLITHIASIS FORMATION IN EXPERIMENTAL HYPERPARATHYROIDISM

PURPOSE We have previously noted marked acceleration in the proliferative activity of parathyroid cells in rats with spontaneous hypercholesterolemia and secondary hyperparathyroidism. Using this proliferative potential we investigated whether transplantation of these enlarged parathyroids into normal rats would induce hyperparathyroidism and renal stones. MATERIALS AND METHODS We used 26-week-old male rats with spontaneous hypercholesterolemia as donors, and 5-week-old normal male Sprague-Dawley rats and rats with spontaneous hypercholesterolemia as recipients. Enlarged parathyroid glands were transplanted into group 1--Sprague-Dawley rats with no treatment, group 2--Sprague-Dawley rats that received FK-506 as an immuno-suppressor, group 3--rats with spontaneous hypercholesterolemia rats that underwent parathyroidectomy plus FK-506 administration and group 4--Sprague-Dawley rats that underwent parathyroidectomy plus FK-506 administration. Parathyroidectomy was performed in recipients before transplantation to ensure a low calcium condition. RESULTS Grafts were rejected within 11 and 15 weeks in groups 1 and 2, respectively. In group 3, 78% of the grafts were successful even after 19 weeks. In group 4 graft survival was 30% at 15 weeks with complete rejection at 19 weeks. In group 3 gradually elevated serum parathyroid hormone was observed as well as stone plaques containing calcium oxalate and calcium phosphate in renal tubules located mainly in the corticomedullary junction. An increased number of plaques was associated with higher parathyroid hormone. CONCLUSIONS Our study shows that transplanted parathyroid glands function with an immunosuppressive agent and the maintenance of hypocalcemic conditions, and they secrete sufficient parathyroid hormone to demonstrate hyperparathyroidism. Plaque in these kidneys indicates an early stage of urolithiasis caused by hyperparathyroidism.