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Biomedical subjects

M Murakumo

Publications and source records attributed to M Murakumo.

7 recordsLinked to original sources
PubMed1998

Surgical repair of anterior hypospadias with fish-mouth meatus and intact prepuce based on anatomical characteristics.

PURPOSE: A variant form of anterior hypospadias, called a megameatus and intact prepuce (MIP), is thought to be less amenable to conventional distal hypospadias repair. The feasibility of using the standard technique with a parameatal-based foreskin flap is described herein. MATERIALS AND METHODS: Nine children with the MIP variant underwent repair. A foreskin flap for urethroplasty was harvested from either the ventral (Mathiew) or unilateral site. The glans was split along with the cleft glanular groove to create the glans wings. The flap was laid on the urethral plate to form a neourethra, and glanulomeatoplasty was completed by approximation of the glans wings. Sleeve reapproximation of the penile foreskin was performed for uncircumcised skin closure. RESULTS: The functional and cosmetic results of the procedure were excellent in 8 cases including 1 with temporary postoperative edema of redundant foreskin. The last case underwent excision of the ventral excess foreskin for cosmetic reasons. CONCLUSIONS: Although the etiology of the MIP variant remains obscure, the urethral plate distal to the meatus is uniformly pliable and healthy in this variant. Furthermore, the ventral portion just proximal to the meatus is well developed and not atretic so that the parameatal ventral foreskin is safely harvested for onlay urethroplasty.

Child, Preschool↗
PubMed1997

Structural changes of collagen components and diminution of nerves in congenital ureteropelvic junction obstruction.

PURPOSE: Three-dimensional arrangements of smooth muscle cells, collagenous component and peripheral nerves of congenital ureteropelvic junction (UPJ) obstruction were studied in order to clarify the pathogenetic mechanism of interaction among these neuro-myo-stromal components. MATERIALS AND METHODS: The UPJ and upper ureters were obtained from 14 patients with congenital hydronephrosis (7 intrinsic and 4 extrinsic obstruction) and 7 normal controls. Three-dimensional arrangement of each structural component was observed by scanning electron microscopy, and the nerve distribution was analyzed with immunohistochemistry for protein gene product 9.5. RESULTS: The UPJ of intrinsic obstruction had structural features as follows. Muscle fascicles were sparse and thin. Each muscle cell was thin in diameter. Intercellular spaces were six to seven times wider than controls. Collagen fibrillar sheaths of smooth muscle cells (pericellular collagen fibrils attached to the basement membrane) were interwoven to form a dense felt-like structure against thin lace-like sheaths in controls. Interstitial collagenous component showed dense and compact structure against loose network of wavy collagen bundles in controls. In the muscular layer, nerve distribution was decreased to about one-third of controls. In contrast, non-stenotic portion of intrinsic UPJ obstruction as well as materials from extrinsic UPJ obstruction showed no structural difference as compared with controls. CONCLUSIONS: In the intrinsic obstruction, nerve fibers were depleted in the muscular layers in the ureteric walls, resulting in dysfunction and atrophy of muscle fibers and an increase of collagen fibers in the muscle layers with abnormal accumulation of intercellular and interstitial collagen. These changes may disrupt the mobility of UPJ and lead to both mechanical and functional obstruction.

Adult↗
PubMed1996

Quantification of renal function with a count-based gamma camera method using technetium-99m-MAG3 in children.

UNLABELLED: To evaluate renal function quantitatively without blood sampling in children, renal uptake by gamma camera renography using 99mTc-MAG3 was compared with plasma clearance by a single blood sample method as the reference. METHODS: Twenty children (15 boys, 5 girls; aged 2-14 yr) with nephrourological diseases were examined prospectively in this study. The patient received an intravenous administration of 5 MBq/kg 99mTc-MAG3 which was prepared using a commercially available kit. Gamma camera renography was performed and the renal uptake per injected dose (%RU) of the 1-min period of postinjection was calculated from a background-corrected renogram curve by computer. The plasma clearance (Clmag) of 99mTc-MAG3 was calculated by the single blood sample method at 35 min postinjection. RESULTS: The %RU of the 1-min period in the 1-3 min postinjection correlated well with Clmag. The best correlation was observed 1-2 min postinjection. The regression equation between total %RU (X) and Clmag (Y) (ml/min/1.73 m2) was Y = -98.509 + 20.373X (r = 0.910, s = 84.19) with standardization by BSA. The best fit regression equation between individual %RU (X) and Clmag (Y) (ml/min/1.73m2) was Y = -43.799 + 19.917X (p = 0.932, s = 43.27). CONCLUSION: The renal uptake method based on separate counts by gamma camera renography using 99mTc-MAG3 does not require a blood sample for quantification of renal function and may be potentially more practical in children.

Adolescent↗
PubMed1995

Three-dimensional arrangement of collagen and elastin fibers in the human urinary bladder: a scanning electron microscopic study.

To clarify the arrangements of collagen and elastin fibers of the urinary bladder, we examined 9 human (male, aged 42 to 72) urinary bladders by scanning electron microscopy with chemical digestion methods. The mucosal layer was divided into 3 portions according to the collagen arrangement: the superficial portion interwoven densely by collagen fibrils, the middle portion layered by flat bundles of collagen fibrils and the deep portion made of a loose network of twisted collagen bundles. In the muscular layer, the smooth muscle fascicles were firmly covered with collagen sheets, while each muscle cell in a fascicle was accommodated by a thin sheath of collagen fibrils. The serosal layer consists of wavy collagen bundles piled up in a sheet, which was intercalated by clusters of adipose cells. Elastic fibers were, on the other hand, sparse throughout the bladder wall, except for denser networks around the blood vessels and muscle fascicles and beneath the peritoneal mesothelium. The arrangements of these components were discussed in relation to the mechanical function and compliance of the urinary bladder.

Adipose Tissue↗
PubMed1993

Scanning electron microscopic studies of smooth muscle cells and their collagen fibrillar sheaths in empty, distended and contracted urinary bladders of the guinea pig.

This study was performed to clarify the structure of muscle cells and the arrangement of surrounding collagen fibrils in the guinea-pig urinary bladder by scanning electron microscopy with two different chemical-digestion methods. Morphological changes in the muscle cells and the collagen fibrils under stretching and contraction were also examined. The smooth muscle cells in the empty bladder were shaped like an unbranched stick 130 microns long. They elongated to 360 microns in the distended bladder, and 48 microns in the contracted bladder. These cells have short lateral processes touching the neighboring muscle cells in an end-to-side fashion. Longitudinal striations on the cell surface due to rows of caveolae and dense bands were recognizable irrespective of the extended or contracted conditions. Transversely arranged wrinkles, which were considered to be produced by surface enfolding during contraction, were marked on the surface of contracted muscle cells. Each muscle cell was accommodated by a thin lace-like sheath made of both separate and small-bundled collagen fibrils. That part of the fibrils in one sheath often extended to participate in another sheath suggested that the collagen sheaths not only modulate cell shape but also provide a structure serving the co-ordinated motion of neighboring muscle cells.

Animals↗
PubMed1991

Scanning electron microscopic studies of tissue elastin components exposed by a KOH-collagenase or simple KOH digestion method.

A KOH-collagenase or simple KOH digestion method was employed for scanning electron microscope (SEM) studies of elastin components in the rat thoracic aorta, mouse urinary bladder, and human ductus deferens. Immersion of the fixed tissues in 30% KOH solution for 8-10 min at 60 degrees C, with or without subsequent collagenase treatment, successfully removed collagen fibrils and basal laminae while leaving cellular and elastin elements unchanged at their original shapes and locations. The internal elastic lamina of the rat aorta appeared as a solid sheet formed by elastin fibrils 0.1-0.2 microns thick, while the medial elastic laminae were more fibrous because of the presence of numerous fine elastin fibers on their surface. Adventitial elastin fibers were of a cord-like shape complicatedly entangled among the adventitial fibroblasts. These fibers were seen as bundles of fibrils 0.1-0.2 microns thick. In the mouse urinary bladder, elastin formed a thin lace-like sheet just beneath the serosal covering of the peritoneum. This sheet was composed of small bundles of fine (0.1-0.2 microns thick) fibrils. The external connective tissue of the human ductus deferens was made up of a three-dimensional loose network of elastin fibers 0.1-1.5 microns thick. These fibers also appeared as bundles of the fine fibrils. These findings indicate that the present method is useful for SEM studies of elastin as well as cellular components in various tissues and organs. This study also maintains that elastin fibers and laminae are basically composed of unit fibrils of 0.1-0.2 microns thickness. As elastin components are arranged specific to individual organs and tissues, it is reasonable that these components are concerned in the characteristic mechanical properties of these tissues and organs.

Animals↗