Hiromitsu Fujii

The proportions of fiber types in human external urethral sphincter: electrophoretic analysis of myosin.

SummaryThe proportions of fast and slow myosin molecules in external urethral sphincter specimens from ten urodynamically normal male bladder carcinoma patients were estimated from the contents of fast and slow myosin light chains in two-dimensional electrophoretic gels. The percentages of fast and slow myosin molecules ranged from 5.0% to 61.4% with a mean of 35.5% and from 38.6% to 95.0% with a mean of 65.5% respectively. It is therefore concluded that the human external urethral sphincter is composed of both fast and slow muscle fibers as well as other voluntary muscles. The human external urethral sphincter is considered to be a highly fatigue-resistant muscle with a very high proportion of slow muscle fibers. In the cases studied so far, there is a great diversity in the proportions of fast and slow myosin molecules; the reason for this remains unknown.

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).

Proportions of fiber types in the external urethral sphincter of young nulliparous and old multiparous rabbits.

SummaryThe proportions of fast and slow myosin molecules in specimens of the external urethral sphincter (EUS) from 6 young nulliparous (6-month-old) and 6 old multiparous (2-year-old) rabbits were studied using myosin heavy chain electrophoresis. The percentages of fast and slow myosin molecules were 80.4±4.5% and 19.6±4.5% in the EUS from nulliparas, and 68.7±6.3% and 31.3±6.3% in the EUS from multiparas. The difference between the two groups was significant (P<0.01). We suggest that a selective decrease in the volume of type 2 (fast) muscle fibers and/or conversion of type 2 to type 1 (slow) muscle fibers had taken place in the EUS of old multiparas. The proportional change in the constitutent muscle fibers of the EUS with aging may play a role in human genuine stress incontinence.

Coexistence of Fast and Slow Myosin Isozymes in Human External Urethral Sphincter. A Preliminary Report

Human external urethral sphincter muscle was isolated for biochemical research. Myosin samples were prepared and pyrophosphate gel electrophoresis and two-dimensional electrophoresis were performed. Assignment in pyrophosphate gel of myosin isozymes of human external urethral sphincter was carried out by making comparisons with those from human rectus abdominis muscle. Myosin light chains in human external urethral sphincter were identified using two-dimensional electrophoresis. Human external urethral sphincter, similar to other voluntary muscles, is composed of fast and slow twitch muscle fibers, since fast and slow myosin components were shown in both pyrophosphate gel and two-dimensional electrophoretograms.

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.