Biomedical subjects

M Ochi

Publications and source records attributed to M Ochi.

At least 91 records · Page 5Linked to original sources

PubMed1999

Dose optimization and indication of Linac radiosurgery for brain metastases.

PURPOSE: The authors have examined treatment effects of linear accelerator based radiosurgery for brain metastases. Optimal doses and indications were determined in an attempt to improve the quality of life for terminal cancer patients. METHODS AND MATERIALS: Ninety-two patients with 162 lesions were treated with Linac radiosurgery for brain metastases between April 1993 and September 1998. To determine prognostic factors, risk factors for recurrence, and appearance of new lesions, univariate and multivariate analyses were performed. To compare the local control between the high-dose (minimum dose > or =25 Gy: prescribed to the 50-80% isodose line) and low-dose (minimum dose <25 Gy) irradiated groups, matched-pairs analysis was performed. RESULTS: Median survival time was 11 months. In univariate analysis, extracranial tumor activity (p<0.001) and Karnofsky Performance Status (KPS) (p = 0.036) were two significant predictors of survival. In multivariate analysis, the status of an extracranial tumor was the single significant predictor of survival (p = 0.005). Minimum dose was the single most significant predictor of local recurrence in univariate, multivariate, and matched-pairs analyses (p<0.05). As to the appearance of new lesions, activity of extracranial tumors was a significant predictor (p<0.05). Side effects due to radiosurgery were experienced in 4 of 92 cases (4.3%). CONCLUSIONS: We concluded that brain metastases patients should be irradiated with > or =25 Gy, when extracranial lesions are stable and longer survival is expected. Combined surgery and conventional radiation may have little advantage over radiosurgery alone when metastatic brain tumors are small and extracranial tumors are well controlled. When extracranial tumors are progressive, the rate of appearance of new lesions in other nonirradiated locations becomes higher. In such cases, careful follow-up is required and a combination with whole brain irradiation should be considered.

Adult↗

PubMed1999

Unilateral sciatic nerve injury stimulates contralateral nerve regeneration.

Axonal outgrowth in tissue cultures was measured to determine whether unilateral peripheral nerve injuries affect contralateral nerve regeneration. The right sciatic nerves of young male Wistar rats were cut at mid-thigh level. Sham operation as a control was limited to the exposure of the nerve without cutting. At day 6 post-surgery, bilateral L5 dorsal root ganglia (DRG) with attached nerve stumps were resected and cultured. Axonal outgrowth from the nerve stump was measured in situ. The contralateral preparations showed longer outgrowths than controls. Therefore the conditioning effect was not merely restricted to the ipsilateral neurons but also affected undamaged sensory neurons of the contralaretal DRG.

Animals↗

PubMed1999

Hyaluronic acid enhances proliferation and chondroitin sulfate synthesis in cultured chondrocytes embedded in collagen gels.

The effects of hyaluronic acid (HA) on the proliferation and chondroitin sulfate (CS) synthesis of chondrocytes embedded in collagen gels were examined. Articular cartilage was isolated from the humerus, femur, and tibia of 21 10-week-old Japanese white rabbits. Chondrocytes isolated by collagenase digestion were embedded in type I collagen gels and cultured in Dulbecco's modified Eagle's medium (DMEM) with various doses of HA for 4 weeks. Histological and biochemical evaluations were performed at postculture weeks 1, 2, 3, and 4. For biochemical evaluations, isomers such as chondroitin 6-sulfate (delta(di)-6S) and chondroitin 4-sulfate (delta(di)-4S) synthesized by cultured chondrocytes were determined by high performance liquid chromatography (HPLC) combined with fluorometry. Morphological and histological studies demonstrated that HA-treated chondrocytes in collagen gel proliferated profusely while maintaining their phenotype. At postculture week 4, 0.1 mg/ml of HA induced an eightfold increase in cell counts compared with HA pretreatment values, or 1.5-fold more than control group. Synthesis of delta(di)-6S (delta(di)-6S content/cell) in groups treated with 0.01 and 0.1 mg/ml of HA significantly increased, while gel accumulation rates in groups treated with 0.1 and 1.0 mg/ml of HA scored significantly higher values than other groups. In collagen gel culture, HA enhanced the proliferation and delta(di)-6S synthesis of chondrocytes while maintaining their phenotype. In clinical application, since the supply of autologous chondrocytes for transplantation is not unlimited, the HA-treated culture method may be useful for increasing the number of chondrocytes and thus improving the quality of implants.

Animals↗

PubMed1999

Combined non-cardiac operations with minimally invasive direct coronary artery bypass grafting.

We report two cases in which Minimally invasive direct coronary artery bypass grafting was followed by other non-cardiac operations in the same operative setting. A left internal thoracic artery-to-left anterior descending artery anastomosis was constructed through a left anterior thoracotomy in both patients. Immediately after Minimally invasive direct coronary artery bypass grafting, one patient underwent a pancreatoduodenectomy for a biliary duct carcinoma and the other patient received a prosthetic graft replacement for an abdominal aortic aneurysm. Minimally invasive direct coronary artery bypass grafting is advantageous in patients with significant coronary artery disease who have to undergo other non-cardiac surgeries.

Aged↗

PubMed1999

Ganglion cysts of the cruciate ligaments detected by MRI.

Eight patients with ganglion cysts arising from the cruciate ligaments of the knee joint underwent arthroscopic excision after the MR examination. The MR findings, clinical features and arthroscopic findings were evaluated comparatively.

Adolescent↗

PubMed1999

Surgical treatment of high-standing greater trochanter.

Eleven patients with high-standing greater trochanter (13 joints) aged 13-36 years underwent surgery. Distal transfer of the greater trochanter (group T) was performed in 4 patients (5 joints) and lateral displacement osteotomy (group L) in 7 (8 joints). The average follow-up duration was 13.4 years in group T and 5.9 years in group L. Clinical results were evaluated by the hip score according to Merle d'Aubigne. The mean hip score in group T was 13.4 points before operation and 15.4 points after operation, and in group L, 12.8 and 17.4 points, respectively. The postoperative clinical results of group L were significantly better than those of group T (P = 0.0494). In radiological evaluation, although the articulo-trochanteric distance (ATD) increased in both groups in group L it improved remarkably from 9.8 to 24.3, indicating a large descending distance of the greater trochanter. The lever arm ratio (LAR) did not change significantly in group T, but it decreased from 1.97 to 1.60 in group L (P = 0.004). This means that the lever arm of the abductors can certainly be extended by lateral displacement osteotomy. Lateral displacement osteotomy is the most effective procedure for high-standing greater trochanter.

Adolescent↗

PubMed1999

Beneficial effect of basic fibroblast growth factor on the repair of full-thickness defects in rabbit articular cartilage.

The effects of exogenous basic fibroblast growth factor (bFGF) on the repair of full-thickness cartilage defects were examined. Four-millimeter diameter, cylindrical defects were made in rabbit articular cartilage and were filled with human recombinant bFGF. The addition of bFGF to the defect induced the formation of a thick cartilage layer composed of chondrocytes and a metachromatic-stained matrix after 6 weeks. The score of the bFGF-treated tissue, as evaluated by a semiquantitative histological scale, was significantly higher than that of the untreated tissue. At 24 weeks, the cartilage-like matrix that contained the proteoglycans and type II collagen was thicker in the bFGF-treated tissue than in the untreated tissue. Immunohistochemical analysis of the tissues at 6-12 weeks with an anti-bFGF monoclonal antibody suggested that a single application of bFGF increased the number of differentiating chondrocytes that synthesized bFGF at a high level. In contrast, immunostaining of the tissues at 6-12 weeks with a monoclonal antibody against proliferating cell nuclear antigen showed that the number of proliferating cells in the bFGF-treated tissue was fewer than in the untreated tissue. These findings suggest that administration of bFGF into cartilagenous defects promotes the differentiation of chondrocytes and their matrix synthesis, and that this growth factor is useful for improving cartilage repair.

Animals↗

PubMed1999

Intraosseous neurilemoma of the sternum.

Sternal benign bone tumor is uncommon. We report a very rare case of intraosseous neurilemoma in the sternum. A girl, 10 years of age, was diagnosed as having a sternal tumor. Computed tomographic scan disclosed a mushroom-shape tumor in the region from inside of the sternum to the ventral soft tissues. Surgical resection was performed. Histopathologic findings showed a typical neurilemoma with Antoni type A and B patterns. No recurrence has been found.

Bone Neoplasms↗

PubMed1999

Appearance of anterior cruciate ligament autografts in their tibial bone tunnels on oblique axial MRI.

The objective of this study was to observe the changing appearance of human anterior cruciate ligament (ACL) grafts in their tibial bone tunnels by MRI using oblique axial images. One-hundred and eight knees in 75 patients were studied by MRI at 1-33 months after arthroscopic ACL reconstructions using double-looped, autogenous semitendinosus and/or gracilis tendons. Knees with poor stability were excluded from this study. The examinations were performed at 0.2T with spin echo proton density and T2-weighted oblique axial images. Appearances of grafts were mainly described on spin echo proton density images based upon time after surgery. The grafts appeared as homogeneous, low signal intensity areas in the bone tunnels at 1 month after the surgery. Ring-shaped low signal intensity areas were observed along the wall of the bone tunnels in the 2- to 3-month group. In many grafts from this group, each tendinous bundle appeared as a low signal area separated by a high signal intensity area. In all cases in the 4- to 6-month group, the thickness of the ring-shaped low signal intensity area had increased, whereas the thickness of the high signal intensity area had decreased. In almost all of the cases, the interior of the bone tunnel gradually became a homologous low signal intensity region by 7 to 12 months after the surgery. According to these results, it is suggested that the maturation of the tendon-bone interface was completed from 6 to 12 months after the ACL reconstruction.

Adolescent↗

PubMed1999

Clinical significance of magnetic resonance imaging (MRI) for focal chondral lesions.

To evaluate the diagnostic potential of magnetic resonance imaging (MRI) and define its role, focal chondral lesions of the femoral surface of the tibiofemoral joint were examined. Full-thickness defects were well detected prospectively (93%) with conventional MRIs initially administered for observation reference of ligaments and menisci. Optimized MRIs, which included right-angled planes to the lesion surface and magnetization transfer contrast (MTC) sequences, delineated the size of lesions (R2 = 0.648,p < 0.0001) and the difference between full-and partial-thickness defects (88% in accuracy). A forward-tilt of 30 degrees to the femoral shaft was the average plane angle that afforded optimal visualization of the chondral lesions. Our findings advocate that routine MRIs are sufficient in detecting severe chondral lesions that require further examination, and the optimized images are highly useful in facilitating the recently developed therapeutic approaches and follow-up studies for articular cartilage defects.

Adolescent↗

PubMed1999

Meniscal rasping for repair of meniscal tear in the avascular zone.

We examined experimentally whether a longitudinal tear in the avascular zone of a rabbit meniscus can be healed by meniscal rasping. A full-thickness longitudinal tear 5-mm long was artificially created in the avascular zone of the anterior segment of both medial menisci. Meniscal rasping was then done on the femoral surface of the right meniscus from the parameniscal synovium to the inner segment including the tear. The left meniscus was left without further treatment as control. Two to 4 weeks after surgery, the hypertrophic synovium was observed invading from the parameniscal region to the injured portion. Eight to 16 weeks after surgery, the tear was almost completely healed. In contrast, neither hypertrophy of the synovium covering the tear nor healing was induced in the control meniscus. The mechanical test showed that there was a significant difference in the tensile strength and the stiffness of the injured portion between the rasped meniscus and the control meniscus. Meniscal rasping is easy to do, is effective, and causes few adverse effects with menisci. This procedure may be a treatment option for clinical cases of meniscal tear in the avascular zone for which we have no effective and clinically applicable methods at present, although further investigation is needed before clinical application.

Animals↗

PubMed1999

Isolated posterior cruciate ligament insufficiency induces morphological changes of anterior cruciate ligament collagen fibrils.

We studied the ultrastructural changes of the human anterior cruciate ligament (ACL) with transmission electron micrograph cross-sections following isolated posterior cruciate ligament (PCL) injury. Biopsy specimens were obtained from the proximal third and anteromedial aspect of the ACL. Fourteen patients with PCL-deficient knees at a mean of 22.1 months from injury to surgery and 5 normal knees amputated secondary to malignant tumors or traumatic injuries were used as controls. A significant difference was found in the number of collagen fibrils per 1 microm2 between the PCL-deficient knee group and the control group. There was a significant difference found in the collagen fibril diameter between the PCL-deficient knee group and the control group. The collagen packing density (the percentage of sampled area occupied by collagen fibrils) was also significantly different between the PCL-deficient knee and the control group. The current study shows that an isolated PCL insufficiency can induce morphological changes in ACL collagen fibrils, suggesting that a PCL insufficiency can have adverse effects on other ligamentous structures in the knee joint.

Adolescent↗

PubMed1999

Rejection and regeneration in peripheral nerve homografts in rats after withdrawal of cyclosporin: morphological and immunohistochemical assessment.

Peripheral nerve homografts 35 mm long were inserted in rats to study rejection and regeneration of nerves after suspension of an immunosuppressant (cyclosporin), and the correlation between the Schwann cells of the host and the donor during the course of regeneration. Sciatic nerve homografts from 36 ACI-RT1a rats were transplanted into Lewis-RT1(1) rats. Isografts were taken from 24 Lewis rats. Cyclosporin 5 mg/kg/day was given subcutaneously for 12 weeks. In the homograft group the myelinated axons that regenerated while the immunosuppressant was being given were covered mainly with Schwann cells from the donor, and after the immunosuppressant was withdrawn both Schwann cells of the donor and axons were rejected. However, while the cyclosporin was being given the Schwann cells of the host migrated into the nerve graft together with a few myelinated axons that escaped rejection, and unmyelinated axons that regenerated after rejection were myelinated by the Schwann cells of host.

Animals↗

PubMed1999

The time-dependent difference of GAP-43 expression between sensory neurons and motoneurons after peripheral nerve transection.

The L5 dorsal root ganglion (DRG) cells and L5 anterior horn (AH) cells of rats were studied and examined immunocytochemically after transection of the sciatic nerve to find out whether there would be time-dependent differences in the increase of growth-associated protein (GAP-43) expression between sensory neurons and motoneurons. On the seventh day after transection at mid-thigh level, the levels of GAP-43 in the DRG cells significantly increased, while those in the AH cells began to increase gradually from the 14th day onward. Transection at the piriform muscle level induced a significant increase in immunoreactivity of GAP-43 on the third day in the DRG cells, and on the seventh day in the AH cells. These results showed that sensory neurons expressed GAP-43 immunoreactivity earlier than motoneurons after peripheral nerve transection regardless of the site, suggesting that sensory neurons might start to produce cytoskeletons for axonal elongation earlier than motoneurons after nerve transection.

Analysis of Variance↗

PubMed1999

Intracranial aneurysms: detection with three-dimensional CT angiography with volume rendering--comparison with conventional angiographic and surgical findings.

PURPOSE: To assess the diagnostic accuracy of three-dimensional (3D) computed tomographic (CT) angiography for intracranial aneurysms. MATERIALS AND METHODS: The 3D CT angiograms obtained in 49 patients with or without intracranial aneurysms were evaluated by four blinded observers. Results were compared with findings at conventional angiography or surgery. A volume-rendering method was used, and 13 images obtained in different directions were reviewed in each study. The diameter of aneurysms was divided into four sizes: large, greater than 13 mm; medium, 5-12 mm; small, 3-4 mm; and very small, less than 3 mm. Results were also evaluated by means of receiver operating characteristic analysis. RESULTS: At conventional angiography, 47 aneurysms, including 14 less than 3 mm, were depicted in 35 patients. The mean sensitivity of CT angiography for very small aneurysms was 64%; small, 83%; medium, 95%; and large, 100%. Some very small aneurysms that were not depicted at conventional angiography were depicted at CT angiography, and one was proved at surgery. CONCLUSION: CT angiography has good sensitivity for depiction of intracranial aneurysms 3 mm or larger and relatively good sensitivity for aneurysms less than 3 mm. CT angiography may be a noninvasive technique for detection of asymptomatic unruptured or ruptured aneurysms.

Adult↗

PubMed1999

An additional monitoring of regional cerebral oxygen saturation to HMPAO SPECT study during balloon test occlusion.

BACKGROUND AND PURPOSE: To increase the reliability of 99mTc-hexamethyl propyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT) study in the evaluation of hemodynamic change with balloon test occlusion (BTO) of the internal carotid artery, we attempted to clarify the usefulness of additional monitoring of regional oxygen saturation of the brain (rSO2). METHODS: During BTO, rSO2 monitoring with transcranial near infrared spectroscopy was performed 17 times on 16 patients. Asymmetrical distribution of the tracer was classified visually as follows: group 1, little or no asymmetry, and group 2, moderate or severe asymmetry. Seven regions of interest (ROI) were defined in the middle cerebral artery area of each hemisphere, and the asymmetry index (AI)=200x(Cnon-Coccl)/(Cnon+Coccl)), where Cnon=mean counts on the nonoccluded side, and Coccl=mean counts on the occluded side were also calculated. Then, mean AI (MAI) was obtained from AI of 7 ROIs for each study. RESULTS: Of the 17 procedures, 10 BTOs were in group 1 and 5 BTOs were in group 2. Two patients did not undergo SPECT study because of the immediate appearance of a neurological deficit with BTO; they were defined as group 3. The MAI in group 1 was 2. 6+/-3.3%, which was significantly smaller than the MAI in group 2 (25.6+/-5.0%, P<0.02). The DeltarSO2 (baseline rSO2-rSO2 during ICA occlusion) with BTO in group 1 was 1.5+/-1.4% (n=10), which was statistically smaller than that in group 2 (5.5+/-1.3%, n=4, P<0.05). The DeltarSO2 in group 3 was 9.0+/-0.0% (n=2). In group 1, however, rSO2 began to decline when the stump pressure fell to 45 mm Hg and always declined when the stump pressure fell below 40 mm Hg. Furthermore, in group 1, a significant correlation was observed between the DeltarSO2 and stump pressure (r=0.85, P<0.0001). CONCLUSIONS: This preliminary study reveals that an obvious asymmetrical SPECT pattern always accompanies a profound decrease in rSO2 and that rSO2 parallels a severe reduction in stump pressure in cases exhibiting a symmetrical SPECT pattern. Thus, the cerebral oximetry sensitively reflects the cerebral oxygenation, and simultaneous measurements of rSO2 and stump pressure with 99mTc-HMPAO SPECT study apparently are useful in evaluating hemodynamic integrity with BTO.

Adolescent↗

PubMed1999

Bandage distraction technique for ankle arthroscopy.

In ankle arthroscopy, the joint space of the talocrural joint is often too narrow for insertion of the scope and instruments. Various distraction devices for this procedure have been used to widen the joint space. Bandage distraction is effective and noninvasive, but it is difficult to extend the posterior joint space sufficiently for insertion of the scope. Here we describe a new bandage distraction method that can extend the posterior joint space adequately. Using our method, the anterior and posterior joint spaces on direct lateral radiographs were measured after adding the distraction force in nine healthy volunteers (18 ankles; three men and 6 women). This was compared to a previously reported method. The posterior joint space was widened a greater amount when our new bandage distraction technique was used.

Ankle Joint↗

PubMed1999

Modified Fontan operation. Considerations for the determination of the appropriate procedure.

BACKGROUND: Although the surgical results of the modified Fontan operation continues to improve, there are various advantages and disadvantages in terms of the post operative condition associated with the Fontan modifications. Late morbidity and mortality are mainly due to arrhythmias, thromboembolic complications, systemic venous hypertension and infective endocarditis. We reported our experience of the modified Fontan operation to determine an appropriate procedure for each patient. METHODS AND RESULTS: Seven patients (ranging from the age 1-14 years) underwent a modified Fontan operation including a lateral tunnel (n = 1), extracardiac conduit (n = 2) and autogenous atrial tunnel (n = 4). There was one hospital death due to sepsis in which the patient underwent lateral tunnel procedure. The mean follow up of another six patients was 20 months (ranging from 1-39 months) and all patients were classified as NYHA class I, and remained in normal sinus rhythm without any thromboembolic complications. CONCLUSIONS: When using the autogenous atrial tunnel, there are potential advantages; it is not associated with thromboembolism or endocarditis and has growth potential. However, in high-risk patients with increased pulmonary vascular resistance, impaired ventricular function and pre-operative atrial arrhythmias, it appears reasonable to use an extracardiac conduit.

Adolescent↗