Biomedical subjects

M Ochi

Publications and source records attributed to M Ochi.

At least 145 records · Page 8Linked to original sources

PubMed1997

Changes in the permeability and histologic findings of rabbit menisci after immobilization.

The knees of mature rabbits were immobilized for 2 to 8 weeks by a long leg cast to examine adverse effects on the meniscus. Some joints were remobilized for 1 to 4 weeks after an immobilization period of either 6 or 8 weeks. Horseradish peroxidase was injected into knee joints, and the degree of permeation into the meniscus was visualized with diaminobenzidine tetrahydrochloride. Menisci were examined histologically by light and transmission electron microscopic study. Injected horseradish peroxidase permeated all areas of the meniscus in nonimmobilized joints. However, permeability of horseradish peroxidase gradually decreased with increasing time of immobilization and was restricted to the superficial layer of the meniscus in the 8-week immobilization group. Degenerative changes in the deep layers of the meniscus were noted in the 6-week immobilization group: 8 weeks of immobilization induced additional degenerative changes. Although permeability of horseradish peroxidase gradually recovered with remobilization, the degenerative changes remained in the deep meniscal layer in the 8-week immobilization group, even after 4 weeks of remobilization. These results clearly show that long-term immobilization of the knee joint causes adverse changes in the meniscus.

Animals↗

PubMed1997

[A case of transitional cell carcinoma of renal pelvis with extremely high serum levels of CA19-9 and CEA].

We report a case of transitional cell carcinoma of the renal pelvis with extremely high serum levels of carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA). A 69-year-old woman was admitted with gross hematuria. Imaging diagnosis revealed a tumor in the left renal pelvis and multiple liver and bone metastases. Serum levels of CA19-9 and CEA were 2,557 U/ml (normal < 36) and 523 ng/ml (normal < 3.8), respectively. She died of cancer progression 3 weeks after admission. An autopsy diagnosis was transitional cell carcinoma of the left renal pelvis. No abnormal findings were recognized in the gastrointestinal organs. Cancer cells showed a positive immunohistochemical staining for both CA19-9 and CEA.

Aged↗

PubMed1997

[Delineation of calf deep veins using 2D-TOF MR venography without contrast media: efficacy of tourniquet and leg-warming].

We evaluated the imaging quality of 2D-TOF MR venography of the lower part of the leg and the efficacy of a tourniquet around the knee and leg-warming. In 8 healthy volunteers, MR venography was carried out under the following four conditions: (a) usual MR venography, (b) MR venography with tourniquet around the knee, (c) MR venography after leg-warming and (d) MR venography with tourniquet after leg-warming. Our results suggested that MR venography with tourniquet after leg-warming is best suited for imaging the veins of the leg. We also compared the diagnostic image quality of MR venography and conventional contrast venography in 7 patients with varices. The results showed no significant differences between the two methods. We conclude that MR venography with tourniquet after leg-warming is a technique that provides reliable information about the veins of the leg.

Adult↗

PubMed1996

Supratentorial arachnoid cyst and associated subdural hematoma: neuroradiologic studies.

CT and MR images of 8 patients with supratentorial arachnoid cyst complicated by subdural hematoma were studied and compared with those of 8 patients who developed nontraumatic subdural hematoma without arachnoid cyst. Of the 8 patients with supratentorial arachnoid cyst, CT and MR disclosed temporal bulging and/or thinning of the temporal squama in all 6 patients with middle fossa arachnoid cysts, and the thinning of the calvaria was evident in another patient with a convexity cyst. Calvarial thinning at the site corresponding to interhemispheric arachnoid cyst was clearly depicted on coronal MR images. In contrast, none of the 8 young patients with nontraumatic subdural hematoma without arachnoid cyst had abnormal calvaria. Temporal bulging and thinning of the overlying calvaria were identified as diagnostic CT and MR features of arachnoid cyst with complicating intracystic and subdural hemorrhage. Radiologists should be aware of this association and should evaluate the bony structure carefully.

Adolescent↗

PubMed1996

Mitogenic action of hydrochlorothiazide on human osteoblasts in vitro: requirement for platelet-derived growth factor.

Long-term use of hydrochlorothiazide (HCTZ), a common diuretic agent for hypertension, has been associated with increased bone density and reduced hip fracture rates in patients. In this study, we sought to examine whether HCTZ has an anabolic effect on the proliferation of human osteoblasts (derived from either vertebrate or rib bone samples) in vitro. Cell proliferation was determined by [3H]thymidine incorporation and cell number counting. In medium supplemented with 1% bovine calf serum, HCTZ significantly and reproducibly increased [3H]thymidine incorporation and cell number. The stimulatory effect was dose dependent in a biphasic manner, with the maximal stimulation (approximately 60% above control, P < 0.001) seen at 1 microM HCTZ. In fresh serum-free medium, HCTZ was ineffective as a bone cell mitogen, indicating that the bone cell mitogenic activity of HCTZ required a serum growth factor (GF). HCTZ at doses greater than 10 microM was inhibitory in the presence or the absence of serum, presumably because of the cytotoxic effects. The serum requirement for the bone cell mitogenic activity of HCTZ could be replaced with a conditioned medium (conditioned with normal human osteoblasts for 24 hours), or with a mitogenic dose (1 ng/ml) of PDGF. The GF requirement was specific for PDGF, because other bone cell-derived growth factors (i.e., TGFbeta, IGF-I, IGF-II, and bFGF) were unable to replace serum for the bone cell mitogenic activity of HCTZ. In summary, this study shows that (1) HCTZ stimulated the proliferation of normal, untransformed, human osteoblasts in vitro; (2) the bone cell mitogenic effect of HCTZ required the presence of a serum GF; (3) the serum requirement could be replaced with a bone cell GF in conditioned medium; (4) the GF requirement was specific for PDGF. In conclusion, we have demonstrated for the first time that HCTZ has a direct anabolic effect on human osteoblasts in vitro, and that the mitogenic activity is dependent on the presence of PDGF. Because increased bone cell proliferation is a key determinant of bone formation, these observations raise the interesting possibility that HCTZ could act directly on bone cells to stimulate bone formation in patients.

Cell Division↗

PubMed1996

Augmented meniscal healing with free synovial autografts: an organ culture model.

We examined whether or not free synovial autografts can augment the healing of lesions artificially created in the human knee meniscus in an organ culture model. The effectiveness of free synovial autografts was also compared with that of fibrin glue (Tisseel). In the control group, the accumulation of cellular components increased at the edge of a 4-mm meniscal defect following culture, although no cells were found to invade the defect. In the fibrin glue group, an increased migration of cells into fibrin glue packed into the defect was observed until 4 weeks following cultivation. However, newly formed collagen produced by the cells in the fibrin glue was minimal even 4 weeks after cultivation. In contrast, in the synovial group, newly formed collagen production, as well as cellular proliferation, increased in the grafted synovium with time after cultivation. By 4 weeks, the gap between the edge of the defect and the grafted synovium was bridged by newly formed collagen tissue, indicating improved histologic repair. Our results suggest that free autogenous synovial tissue grafts in meniscal lesions are superior to fibrin glue, and that interpositional synovial autografts to augment repair of meniscal tears in the avascular zone may be clinically useful.

Adolescent↗

PubMed1996

MRI of intracranial meningeal malignant fibrous histiocytoma.

We describe the CT and MRI findings in a patient with primary intracranial meningeal malignant fibrous histiocytoma (MFH). CT delineated the anatomical relations and MRI aided in tissue characterisation. To our knowledge, this is the first report describing the MRI findings in primary intracranial meningeal MFH.

Aged↗

PubMed1996

Aortic dissection extending from the left coronary artery during percutaneous coronary angioplasty.

A 72-year-old woman with acute aortic dissection as a complication of percutaneous coronary angioplasty was successfully treated. She received a graft replacement of the ascending aorta as well as triple coronary artery bypass grafts. The dissection had extended from the left coronary artery. Although acute aortic dissection is a rare complication of percutaneous coronary angioplasty, physicians and cardiac surgeons should keep its potential occurrence in mind.

Acute Disease↗

PubMed1996

Narrow photon beam dosimetry for linear accelerator radiosurgery.

The dosimetric characteristics of linear accelerator radiosurgery for 10-MV X-ray were measured. Measurement of the relative output factor and tissue maximum ratio with a microchamber produced results equivalent to those of measurement with X-ray film. The 80% isodose level width measured with the microchamber was significantly smaller than that measured with the X-ray film. For the measurement of relative output factor and tissue maximum ratio, a microchamber seems to be the more appropriate choice. X-Ray film was found to be suitable for beam profile measurement.

Phantoms, Imaging↗

PubMed1996

Permeation from the synovial fluid as nutritional pathway for the anterior cruciate ligament in rabbits.

The anterior cruciate ligament of the knee receives its nutrition from a direct vascular supply and by permeation of nutrients from synovial fluid. In order to quantitate the relative importance of these two routes and to compare the anterior cruciate ligament with the medial collateral ligament, we injected [3H]methyl-glucose as a tracer intravenously or directly into the knee in rabbits. Tracer concentrations in plasma, synovial fluid, the anterior cruciate ligament and the medial collateral ligament were analysed by a pharmacokinetic compartment model developed for this study. The contribution of [3H]methyl-glucose permeation from the synovial fluid was calculated at 59.7% in the anterior cruciate ligament and at 18.1% in the medial collateral ligament. We concluded from these results that the nutrition for the medial collateral ligament, which is an extraarticular structure, is provided mainly by its vascular supply. In contrast, synovial fluid permeation is an important transport route for small molecules for the normal anterior cruciate ligament.

Animals↗

PubMed1996

Delay of the denervation process in skeletal muscle by sensory ganglion graft and its clinical application.

We examined the effects of dorsal root ganglion isografts on the denervation process of skeletal muscle. A segment of sciatic nerve was removed from each of 25 inbred Wistar-Kyoto rats. Fifteen were set aside as controls. In the remaining 10 rats, isogeneic cervical dorsal root ganglia were grafted to the severed distal stump of the common peroneal nerve. Between day 72 and day 286 postoperatively, both controls and recipients were killed after twitch and tetanic tension recording of the extensor digitorum longus was performed. The wet muscle weight and the twitch and tetanic tensions of the denervated extensor digitorum longus in the graft group were significantly greater than those in the control group. The mean area of the denervated tibialis anterior muscle fibers in the graft group also was significantly larger than that in the control group. In electron and light microscopic images, nerve cells along the periphery of each dorsal root ganglion were found surviving with regenerating axons throughout the experimental period. Numerous myelinated axons were observed in the common peroneal nerve of the graft group, and there were significantly more axonal branches in the extensor digitorum longus of the graft group than in the extensor digitorum longus of the control group. Thus sensory nerve fibers from the grafted dorsal root ganglia had certain beneficial effects to slow the denervation process, presumably secreting trophic factors into the denervated muscle. Clinically, we have transferred avulsed dorsal root ganglia in cases of total brachial plexus avulsion directly into denervated skeletal muscle. This procedure, accompanied by nerve crossing procedures, will probably keep denervated skeletal muscle in a better condition until regenerating motor axons from the repair site reach their target muscle.

Animals↗

PubMed1996

Motor nerve conduction studies on children with spinal muscular atrophy.

Median and posterior tibial motor nerve conduction studies were performed on 10 children with spinal muscular atrophy (SMA). Three patients with SMA type I, in whom rapid deterioration occurred, showed reduced motor nerve conduction velocity and a remarkably low M-wave amplitude in both nerves. In type II and III patients, the motor nerve conduction velocity was normal in the median nerve, although the M-wave amplitude was small in the tibial nerve. In four patients, a reduction of the M-wave amplitude was observed as clinical symptoms advanced. These findings may suggest that motor conduction studies in spinal muscular atrophy provide complementary information for understanding the pathogenesis and are also useful to clarify the heterogeneity of this disease.

Child↗

PubMed1995

Effects of transient forebrain ischemia on long-term enhancement of dopamine release in rat striatal slices.

We studied the effects of transient forebrain ischemia in vivo on long-term enhancement of dopamine (DA) release from rat striatal slices. One hour after the high-frequency tetanic stimulation (HFTS) or L-glutamate (10(-6) M) application in Mg(2+)-free medium to striatal slices, the high concentration of KCl (high K+)-evoked DA release was measured. Tetanic stimulation or L-glutamate application significantly potentiated the high-K(+)-evoked DA release. When striatal slices were prepared from rats exposed to 3 min of ischemia followed by 24-h survival, the enhancement of DA release by HFTS was unaffected by ischemia. In contrast, the enhancement of DA release by HFTS was impaired in rats exposed to 5 min or 10 min of ischemia. In addition, high K(+)-evoked DA release per se was significantly impaired by 10 min of ischemia. The enhancement of DA release elicited by pretreatment with L-glutamate was also impaired in the rats exposed to 5 min of ischemia. When striatal slices were prepared from rats exposed to 5 min of ischemia with 7-day survival, the enhancement of DA release by HFTS was still impaired. The present results indicate that the neuronal mechanisms of the enhancement of DA release may be more sensitive to impairment from short periods of ischemia. Furthermore, the results suggest that an impairment of long-term enhancement of DA release by ischemia may be related the dysfunction of motor performance in rats exposed to ischemia.

Animals↗

PubMed1995

Superior nerve anastomosis using a low-output CO2 laser on fibrin membrane.

BACKGROUND AND OBJECTIVE: To date, no procedure of laser-aided nerve anastomosis has yet proved to be consistently superior to suture nerve repair. This study examines a new method for nerve repair using a low output CO2 laser and fibrin membrane to ascertain the efficacy of this method for nerve regeneration in comparison with the suture method. STUDY DESIGN/MATERIALS AND METHODS: Both sciatic nerves of 42 Wister rats were used. The left sciatic nerves were cut and reconnected using 70 mW of irradiation on fibrin membrane bridging the nerve stumps, whereas the right sciatic nerves were repaired with two stitches of epineuro-fascicular sutures. RESULTS: No deleterious effect of the irradiation on nerve regeneration was demonstrated at any time after surgery. The number of myelinated axons larger than 5 microns in diameter and the mean diameter of mylinated axons 8 weeks after surgery were significantly larger in the laser group than those in the suture group (P < 0.05). CONCLUSION: The results suggest this new method may be useful and effective for clinical nerve repair.

Anastomosis, Surgical↗

PubMed1995

Immune response to fresh meniscal allografts in mice.

To date, no study of allogeneic meniscal transplantation has investigated both the host cellular immune response and the humoral immune response. Using inbred mice, we examined cellular and humoral immunity to meniscal allografts through the mixed lymphocyte culture reaction and a complement-dependent cytotoxicity test. We also examined the histology of an allogeneic meniscus transplanted subcutaneously. The stimulation index of the mixed lymphocyte culture seen after placing fresh meniscal allografts subcutaneously was not significantly higher than when isograft controls were similarly placed. Following placement of the allografts, no specific antibodies were detected in serum throughout the 24-week period after grafting. Although viable fibrochondrocytes in the allogeneic meniscus decreased in number and lymphocyte infiltration around the allogeneic meniscus was noted at Week 2, no remarkable infiltration of lymphocytes into the meniscus was observed. These results indicate that in our experimental mouse model, a fresh meniscus apparently is not sufficiently immunogenic to induce a systemic reaction. Our results suggest that a fresh allogeneic meniscus can be transplanted without any special treatment to decrease its immunogenicity.

Animals↗

PubMed1995

Allogeneic deep frozen meniscal graft for repair of osteochondral defects in the knee joint.

Osteochondral defects in the knee joints of five patients caused by trauma or osteochondritis dissecans were repaired using deep-frozen allogeneic meniscal grafts. Three patients were male and two were female, with a mean age of 26.4 years. The mean follow-up period was 31 months. Postoperative magnetic resonance imaging (MRI) at all periods clearly showed a smooth and congruous articular surface, although the signal intensity of the grafted meniscus was not the same as that of the articular cartilage. Second-look arthroscopy performed approximately 1 year after surgery demonstrated that the grafted meniscus was well bonded to the grafted site, not sunken; there was no gap between the grafted meniscus and the surrounding articular cartilage, indicating that the grafted meniscus functions as a part of the articular surface. Histologic examination revealed that host cells had infiltrated into the meniscus and that cells surrounded by thin collagen fibrils were morphologically similar to fibrochondrocytes. Thus, the acellular grafted meniscus regenerated as meniscal tissue and formed an articular surface, although hyalinization did not occur. Our results suggest that deep-frozen allogeneic meniscal grafting is a useful method to repair osteochondral defects in the knee joint.

Adolescent↗

PubMed1995

Cerebral MRI and spectroscopy in Sjögren-Larsson syndrome: case report.

We report MRI and MRS of the brain in a patient with Sjögren-Larsson syndrome (SLS) in whom fatty alcohol oxidoreductase (FAO) deficiency has been verified. MRI showed periventricular lesions, high intensity on T2-weighted and low intensity on T1-weighted images at trigones of the lateral ventricles. 1H-MRS of these lesions revealed high lipid and low N-acetyl aspartate peaks. We presume such lipids in periventricular lesions with high T2 signal may be pathognomonic of SLS.

Adult↗

PubMed1995

Promotion of sciatic nerve regeneration in rats by a new neurotrophic pyrimidine derivative MS-430.

1. The effects of a new neurotrophic pyrimidine derivative of MS-430 on nerve regeneration was examined using Wistar rats whose left sciatic nerve had been subjected to controlled injury. 2. The functional recovery and the packing density of common peroneal nerve axons were significantly enhanced with the administration of 3 mg/kg/day of MS-430. 3. These results suggest that MS-430 is a promising candidate as a neurotrophic drug for clinical use.

Animals↗