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Biomedical subjects

Y Hirasawa

Publications and source records attributed to Y Hirasawa.

At least 19 recordsLinked to original sources
PubMed1992

Effect of lansoprazole on intragastric pH. Comparison between morning and evening dosing.

Lansoprazole is a newly developed proton pump inhibitor. The purpose of this study was to determine whether morning or evening dosage gave better control of 24-hr intragastric pH. In this study, we examined the antisecretory effect of lansoprazole by repeated intragastric pH monitoring on four occasions in eight normal subjects and compared median 24-hr pH values and pH threshold time of pH greater than or equal to 4 between morning and evening dosing, following the administration of lansoprazole 30 mg once daily in either the morning or evening for seven days. Intragastric pH was monitored before and after seven days of treatment. Both morning and evening dosing caused a rise in the intragastric pH. Median pH for 24 hr was 4.3 and 1.6 with and without lansoprazole morning dosing and 4.6 and 2.1 for evening dosing, respectively. The pH threshold curve shifted to the right with lansoprazole treatment in either case. However, no differences were found between morning and evening dosing in terms of median 24-hr pH values or pH threshold time of pH greater than or equal to 4. These results indicate that lansoprazole can be given once daily in either the morning or evening because of its potent and long-lasting antisecretory activity.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1992

Cystic radiolucencies of carpal bones, distal radius and ulna as a marker for dialysis-associated amyloid osteoarthropathy.

Patients on long-term hemodialysis (HD) are known to develop amyloid osteoarthropathy, evidenced as cystic radiolucencies on X-rays of the affected joints. To study the relationship between cystic radiolucencies and amyloid osteoarthropathy in 394 patients, we classified the severity of the cystic radiolucencies seen in the wrist joint on a 4-point scale and evaluated the association between lesion severity (grade) and several parameters. Biopsy was performed in 8 patients with 11 bone cysts of the wrist joint who had been operated for carpal tunnel syndrome. HD for 10 years or longer, age 50 or older and the presence of carpal tunnel syndrome were associated with severe cyst rating. There was no association between lesion grade and serum level of PTH-C, aluminum or beta 2-microglobulin (B2M). Ten of the 11 biopsied bone cysts in 8 patients with carpal tunnel syndrome demonstrated amyloid deposits which reacted with B2M. We conclude that a cystic radiolucency observed in the wrist joint of a patient undergoing HD indicates the deposition of amyloid. The cyst grade provides a useful marker for the severity of amyloid osteoarthropathy in HD patients.

Adult↗
PubMed1992

[Pulmonary distribution of 99mTc-technegas--a comparative study of radioactive inert gases].

99mTc-technegas (99mTc-gas), which consists of fine particles, is produced in carbon crucibles burned at 2500 degrees C. On this study, the particle size of 99mTc-gas was measured and the pulmonary distribution of 99mTc-gas was assessed in 28 patients with various pulmonary diseases. Most particles were 5-30 nm in diameter as determined by electron microscopy. In a clinical study, about 37 MBq of 99mTc-gas was inhaled three times during deep breathing in a sitting position. In a comparative study with radioactive inert gases (133Xe, 81mKr), 99mTc-gas showed a similar distribution to the inert gas in most patients, although some with obstructive disease showed hot spots in the lung fields. In patients with severe obstructive change, marked deposits of 99mTc-gas was noted in the central airways, but 99mTc-gas penetrated to the peripheral lung field. This result suggests that 99mTc-gas can be used to evaluate ventilatory function even in patients with chronic obstructive pulmonary diseases.

Gases↗
PubMed1992

[Callus formation and microvascular regeneration during the fracture healing process in the rat femur].

Correlation between the callus formation and its microvascular regeneration during the fracture healing process in the rat femur was examined under SEM and TEM utilizing the plastic injection method. Stabilization of bony fragments was provided by a miniature external fixator. Normal periosteal microvasculature consisted of 2 layers. In the outer layer, arterioles and venules formed the course network. In the inner layer, capillaries were situated in contact with the compact bone, forming polygonal meshes. In the medulla, the central longitudinal artery gave rise to numerous arterioles, which communicated with sinusoidal capillaries. The proliferation of the internal layer of the periosteal capillary network was observed in the periosteal callus. It is revealed that the trabecular structure of the periosteal and medullary calluses depended on their microvascular architecture. The anastomoses of newly-formed capillaries at the fracture site started first from the outer layer of the periosteum extended to the medulla then finally to the inner layer of the periosteum.

Animals↗
PubMed1992

[Natural history and biologic mechanism of the transition from grafted bone to extra-cortical bone bridge over porous-coated segmental prostheses].

The biologic mechanism of extra-cortical bone bridge formation over a porous-coating segmental prosthesis was studied. A 6 cm segment of the femoral diaphysis was bilaterally resected and replaced by a segmental prosthesis in 32 adult dogs. A morselized autogenous bone graft mixed with marrow cells was applied around the prosthesis and the adjacent cortex. The animals were sacrificed at 2, 4, 8 and 12 weeks postoperatively. Tissue samples from the extra-cortical bone formation zone were analyzed by fluorescent and light microscopy and transmission electron microscopy. Active intramembranous new bone formation occurred appositionally. Osteogenic foci were formed in the fibrous tissue by the determined osteogenic precursor cell contained in the marrow cells. Woven bone formation occurred within the matured callus through endochondral ossification. Extra-cortical bone bridges depended on bone/marrow grafts with good vascularity and mechanical stability as important ingredients. Extra-cortical bone bridges were reduced in volume and matured with time.

Animals↗
PubMed1991

Bilateral open laminoplasty using ceramic laminas for cervical myelopathy.

Evaluation was done of 65 patients with cervical myelopathy treated by bilateral open laminoplasty using artificial laminas, between 1984 and 1988, who had been followed for more than 2 years. The mean recovery rate on the Japanese Orthopaedic Association scoring system was 65% in all cases, and 72% in the cases with no other complications. The artificial laminas appeared well adapted to the laminas in computed tomography and dynamic radiographic examinations, and there were no cases of reduction of the enlarged canal. Postoperative restriction of the range of motion of the cervical spine was lessened by the positioning of lateral grooves, more appropriate external fixation, and posterior flexion exercise after operation. This procedure is not technically complicated, it does not involve appreciable blood loss during operation, it prevents grafted free fat from migrating into the spinal canal, and is advantageous for posterolateral bone chip grafting.

Ceramics↗
PubMed1991

[Staining of bone canaliculi using decalcified bone tissues].

Recently we were able to stain bone canaliculi using the decalcified bone tissues, according to a modified method of the Bodian staining method, which is commonly used for staining the nerve fibers with silver impregnation of protargol. The bone tissues from normal rabbits, rats, and humans were decalcified with buffered EDTA solution after 10% formalin fixation. The tissues were embedded in paraffin and were sliced at 4 microns then the sections were attached to the gelatin-coated glass slides. These sections were treated first with potassium dichromate followed by 2% protargol solution containing copper. After gold chrolide treatment, they were immersed in oxalic acid. Both the lacunae and canaliculi of osteocytes were stained black in sharp contrast to bone matrix of red purple. Using the present staining method, the bone canaliculi were clearly detectable in fine details without producing apparent artificial damage of soft tissues. The canaliculi showed also markedly complex fine structures. By combining the present staining method with eosin or toluidine blue staining, we were able to recognize even immature osteocytes in enchondral ossification at growth cartilage with fine bone canaliculi. From these results, we conclude that the present method is very useful in histopathological studies of the lacuna-canalicular system of osteocytes in the decalcified bone tissues.

Animals↗
PubMed1991

[The distribution of S-100 protein positive chondrocytes in the human articular cartilages under aging or diseased conditions].

There have been few reports on the localization of S-100 protein positive chondrocytes in the human articular cartilages. We studied 59 articular cartilages of the aged subjects, 65 osteoarthritic (OA) and 39 rheumatoid arthritic (RA) articular cartilages, to detect the histological localization of S-100 protein using immunoperoxidase method (ABC). The results obtained from normal cartilages demonstrated strongly positive cells representing hypertrophic chondrocytes in the perivascular areas of the neonatal articular cartilage and in the deep zone of the infant articular cartilage. The moderately positive cells were found in the intermediate zone of infant and adult articular cartilages. In mild OA, there were many positive chondrocytes in the intermediate zone with erosion of the surface layer, while in moderate or severe OA many strongly positive cells were found in clusters. The hypertrophic cells in the metaplastic cartilage arising from bone marrow in subjects with severe OA, or from pannus after RA were also positive. It is therefore, suggested that S-100 protein may be correlated with the metabolic activity of the cartilage matrix such as collagen and proteoglycan, as reported in the literature. S-100 protein further, appears to be useful for evaluating histologically the activity of cartilage repair in the pathologic human articular cartilages.

Adolescent↗
PubMed1991

[Salivary epidermal growth factor in patients with peptic ulcer].

Recent animal studies suggest salivary epidermal growth factor (EGF) has a cytoprotective effect in the upper GI tract and is one of the important factors to promote the healing of experimental ulcer. The present study was undertaken to clarify the role of salivary EGF in peptic ulcer patients. Saliva samples were collected from 129 endoscopically normal subjects and 232 peptic ulcer patients. Salivary EGF concentration was measured by RIA. Salivary EGF output in normal subjects was 5.26 +/- 0.26 (ng/5 min) (mean +/- SE). Those in patients with gastric ulcer (GU), duodenal ulcer (DU) and gastroduodenal ulcer (GDU) were 10.74 +/- 0.15, 8.13 +/- 0.83 and 9.79 +/- 0.91. EGF output in GU and GDU patients were higher than that in normal subjects respectively. Tractable GU patients (healed within 3 months with regular regimen) had higher EGF output than intractable GU patients. Among tractable GU patients, those who had healing within 8 weeks had higher output. EGF output in patients with recurrent GU was lower than that in non-recurrent GU patients. In 10 GU patients, EGF output became higher in healing stage than in active stage. Salivary EGF may promote the healing and prevent the recurrence of human gastric ulcer.

Adult↗
PubMed1990

An experimental study of nerve regeneration through chemically treated allografts.

We carried out experiments in rabbits to determine whether treating nerve transplants with gradually increasing concentrations of ethanol, ether and ficin would inhibit the graft-host immune reaction to the allograft. After treatment with ethanol, the basal laminar scaffold of the Schwann cell remained intact and there was satisfactory axonal regeneration. The results after additional treatment with ether or ficin did not achieve such good results. Preservation of the basal lamina is considered to be the essential factor in allowing neural regeneration in these circumstances.

Animals↗
PubMed1990

Clinical and microangiographic studies on rupture of the E.P.L. tendon after distal radial fractures.

The authors have treated 14 cases of spontaneous rupture of extensor pollicis longus tendon after fractures of the distal end of the radius, most of which were undisplaced or only slightly displaced. A microvascular study on five cadavers revealed that this tendon is subject to mechanical bending and attrition, has no mesotenon and has a poorly vascularised portion about 5 mm in length, which may be a cause of spontaneous rupture of the tendon.

Adolescent↗