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Biomedical subjects

O Ishida

Publications and source records attributed to O Ishida.

At least 73 records · Page 4Linked to original sources
PubMed1993

Origin of Schwann cells in peripheral nerve allografts in the rat after withdrawal of cyclosporine.

The origin of Schwann cells in peripheral nerve allografts following rejection was determined by immunohistochemistry. Sciatic nerve allografts from ACI-RT1a rats were transplanted into Lewis-RT1l sciatic nerves using epineurial sutures. Isografts were taken from Lewis-RT1l rats. Cyclosporine (CsA) was administered subcutaneously daily, 5 mg/kg for 12 weeks, to the rats in each group. Allografts with CsA were sacrificed in groups at 12, 14, 16, 20, 24, and 36 weeks postoperatively during the rejection and recovery phase. Allografts and isografts without CsA were evaluated at 3, 6, 12, and 24 weeks. Nerves were frozen and cross sections immunohistochemically stained against Lewis rat HLA (RT1) and against Schwann cells (S-100 antigen). Allografts without CsA demonstrated minimal reaction to anti-Lewis compared to control isografts, which stained positively at all times. Schwann cells were not as well-stained in the allografts. Allografts with CsA showed reactivity to S-100 at 12 weeks, but minimal activity to Lewis antibody. Minimal reactivity to both S-100 and Lewis existed at 16 weeks, but increased gradually by 24 and 36 weeks. Therefore, Schwann cells from the recipient migrate into the graft and replace the Schwann cells from the donor following rejection.

Animals↗
PubMed1993

Enhanced tumor targeting of doxorubicin by ganglioside GM1-bearing long-circulating liposomes.

Doxorubicin (DXR) was encapsulated in long-circulating liposomes, composed of ganglioside GM1 (GM1)/distearoylphosphatidylcholine (DSPC)/cholesterol (CH) (0.13:1:1 in molar ratio) and sized to approximately 100 nm in mean diameter, with 98% entrapping efficiency by the transmembrane pH gradient method. Free DXR, DXR-DSPC/CH and DXR-GM1/DSPC/CH liposomes were injected intravenously into Colon 26 tumor-bearing Balb/c mice via the tail vein at a dose of 5.0 mg DXR/kg. DXR-GM1/DSPC/CH liposomes gave a higher blood level of the drug than did DXR-DSPC/CH liposomes or free DXR up to 24 hours after injection, and the area under the blood concentration-time curve (AUC) for DXR-GM1/DSPC/CH liposomes was 1.5 or 526 times higher than that for DXR-DSPC/CH liposomes or free DXR, respectively. DXR-GM1/DSPC/CH liposomes gave a decreased DXR concentration in the reticuloendothelial system (RES) of the liver and the spleen. Both liposomal formulations effectively reduced the DXR concentration in the heart as compared with that in the case of free DXR. At 6 hours after i.v. injection, DXR-GM1/DSPC/CH liposomes provided an approximately 3.3- or 9-fold higher peak DXR level in the tumor as compared with DXR-DSPC/CH liposomes or the free drug, respectively. These high tumor levels of DXR appear to reflect the prolonged residence time of the liposomes. The results suggest that encapsulation of DXR in GM1-bearing long-circulating liposomes will be useful for cancer chemotherapy.

Animals↗
PubMed1993

Regeneration following rejection of peripheral nerve allografts of rats on withdrawal of cyclosporine.

Sequential changes in the sciatic nerve function and morphology were evaluated in transplanted nerve allografts from ACI-RT1a into Lewis RT1I rats after withdrawal of cyclosporine, which had been administered subcutaneously daily (5 mg/kg) for 12 weeks. Experimental groups were established as follows: (1) allograft with cyclosporine (evaluated and sacrificed at 12, 14, 16, 20, 24, and 36 weeks, 10 rats at each week), (2) allograft without cyclosporine (12 and 24 weeks, 10 rats at each week), (3) isograft with cyclosporine (12 and 24 weeks, 6 rats at each week), and (4) isograft without cyclosporine (12 and 24 weeks, 10 rats at each week). Regeneration was evaluated through walking track analysis, electrophysiologic studies, weight of the anterior tibial muscle, and axon counts, diameter, and myelin thickness. Regeneration was observed through 14 weeks after grafting; by 16 weeks, all rats had demonstrated a clear rejection phase, but regeneration indices then recovered quickly by 24 weeks. Electron microscopy of both the graft and distal nerve suggested that both Schwann cells and axons were affected by the rejection phenomenon. Allografts without cyclosporine showed inferior regeneration histologically at 24 weeks. Morphologically, allografts were equivalent to isografts treated with cyclosporine at 24 weeks. Although nerve allografts are rejected after cyclosporine withdrawal, they may still serve as effective nerve conduits.

Action Potentials↗
PubMed1993

Complications and results of scapho-trapezio-trapezoid arthrodesis.

Forty cases of scapho-trapezio-trapezoid (STT) arthrodesis were reviewed. Indications for the procedure included rotatory subluxation of the scaphoid (30 patients) and STT arthrosis (ten patients). Follow-up time averaged 41 months. Ten patients (25%) required 13 additional procedures: operations for nonunion or a fracture of the distal radius after bone harvesting, partial radial styloidectomy, first carpometacarpal joint arthroplasty, and wrist arthrodesis. Complications without surgeries were seen in several cases: pin-tract infection, sympathetic dystrophy, delayed union treated with brace, and radial nerve irritation. Overall, complications were observed in 21 patients (53%), some having more than one complication. Degenerative arthritis at joints surrounding the STT mass was suspected based on roentgenograms in five cases. Twenty-three patients (58%) became pain free or had minimal pain with a limited arc of motion. Twenty of 34 patients (59%) returned to their regular work or the same job, and 27 (68%) reported good to excellent results. Although STT arthrodesis can provide a painless wrist with a limited arc of motion in most patients, complications are frequent.

Adult↗
PubMed1992

[MR imaging of thyroid masses].

Magnetic resonance (MR) imaging was performed in 35 patients with histologically proved thyroid masses. Gadopentetate dimeglumine was used in 25 of these cases. The thyroid tumors were analyzed by MR imaging as to shape, margin, pseudocapsulation, homogeneity, and enhanced pattern. Gd-DTPA was helpful in identifying pseudocapsules and showing the extent of the tumor. Papillary carcinoma tended to display unclear margins, heterogeneous intensity, and inhomogeneously enhanced patterns. In follicular adenoma, the tumor margin was smooth and pseudocapsules were clearly detected. Follicular adenoma was enhanced homogeneously, but it was difficult to distinguish follicular adenoma from follicular carcinoma by MR imaging. Adenomatous goiter was delineated as multiple nodules with smooth margins, but without pseudocapsules. These nodules were enhanced in various ways after Gd-DTPA administration.

Female↗
PubMed1992

[Evaluation of US contrast medium (LEVOVIST) to experimental liver cancer].

Enhancement of liver cancer on ultrasonography (US) by injection of new contrast medium (LEVOVIST) was performed in rats with 3'-methyl-4-dimethylaminoazobenzene-induced hepatic carcinoma. Echosignals of cancer nodules increased remarkably after the intrahepatic arterial injection of LEVOVIST (200, 300 mg/ml), and contrast enhancement was observed for at least 15 minutes. Furthermore, US after the intrahepatic arterial injection of LEVOVIST (200 mg/ml) can visualize small nodule, which was not recognizable on plain US. As a result of increased echosignals of normal liver parenchyma after the intra-portal injection of LEVOVIST (300 mg/ml), the cancer nodules were demonstrated as hypoechoic. These results indicate that this new contrast medium for sonography is effective in the diagnosis of liver cancer.

Animals↗
PubMed1992

[Electron-microscopic study on the effect of an expandable metallic stent placement in the aortic wall].

As part of a series of basic experiments on using metallic stents for treatment of vascular stenosis, a chronological examination of changes in dog aorta following implantation of a self-expandable metallic stent was conducting using transmission and scanning electron microscopy. The Giantruco stent was placed in the abdominal aorta via the right carotid artery. One week after insertion, the aortic intima was depressed and degenerative changes observed in both endothelial and medial smooth muscle cells. After 2 weeks, except for the bend portion, the stent was covered with neointima. The neointimal surface was covered by premature endothelial cells with abundant microvilli and prominent nuclear protrusions. Under the endothelial cells, immature mesenchymal cells, such as fibroblast, were scattered throughout the edematous intercellular space. At 4 weeks, the stent was completely covered by neointima and the endothelial cells had flattened and few microvilli were in evidence. In this thickened intima, premature smooth muscle cells with myofilaments and basement membranes were observed but, around them, few collagen fibers and only occasional elastic fibers were found. At 6 weeks, the intimal surfaces were flat and smooth with a slight intimal elevation over the stent. No thrombus was observed throughout the period of the experiment. The above results indicate that dilation using metallic stents may be a useful method for treatment of vascular stenosis.

Animals↗
PubMed1992

P-31 MR spectrum and histologic changes after intrahepatic arterial injection of iodized oil in normal and cirrhotic rat liver.

Injection of iodized oil (Lipiodol) into the hepatic artery is widely used in the diagnosis and treatment of hepatocellular carcinoma. However, no reports have yet appeared concerning temporal changes in hepatic metabolism following Lipiodol injection. In the present study, Lipiodol was injected into the hepatic arteries of normal and cirrhotic rats, successive P-31 MR measurements were performed, and temporal changes in metabolism were compared with histologic findings. Both normal and cirrhotic rats displayed minimum levels of beta-ATP/PME and beta-ATP/Pi 5 days after hepatic arterial injection of Lipiodol. However, 10 days after injection these values had reverted to the preinjection levels. The metabolic dysfunction observed in the liver following hepatic arterial injection of 0.3 ml/kg b.w. Lipiodol was transient. Moreover, no distinct differences were observed between P-31 MR changes in normal and cirrhotic rats. Conversely, histologic impairment assessed on the basis of hepatic necrosis ratios was most severe 2 days after hepatic arterial injection in both normal and cirrhotic rats, and this did not coincide with the time of the most pronounced metabolic impairment as inferred from P-31 MR changes.

Animals↗
PubMed1991

Free vascularized whole joint transfer in children.

Reconstruction of the traumatized finger joint with epiphyseal destruction has long been problematic. Since free vascularized whole joint transfer was introduced as a treatment for joint and epiphyseal destruction, this procedure has been selected as an alternative treatment because it may provide a growing epiphysis. We have reviewed our series of 19 joint transfers. Mean age at operation was 6.2 years (range 3 to 12). Average active range of motion was 31 degrees/61 degrees for the group with posttraumatic reconstruction (n = 12) and 21 degrees/43 degrees for the group with reconstruction of a congenital deformity (n = 7), with an overall average of 27 degrees/54 degrees. Average range of motion following transfer of an metatarsophalangeal (MTP) or metacarpophalangeal (MCP) joint to an MCP joint position was 39 degrees/75 degrees (n = 4); proximal interphalangeal (PIP) to PIP transfer was 22 degrees/39 degrees (n = 13); and PIP to MCP transfer was 38 degrees/51 degrees (n = 2). The proximal phalanges in MCP joints transferred to the MCP position grew an average of 7.0 mm, and the middle phalanges of joints transferred to the PIP position grew 4.3 mm. Almost normal growth was observed in all transferred joints except two that showed premature epiphyseal closure. Indications for this procedure and techniques to improve range of motion are described.

Arthroplasty↗
PubMed1990

[MR imaging of optic neuritis using short T1 IR (inversion recovery)].

We evaluated the ability of MRI using short T1 inversion recovery (STIR) to diagnose optic neuritis. Eleven patients with previous or recent attack of optic neuritis were studied with MRI at 0.5 tesla. STIR images revealed high signal regions in 7 of 12 symptomatic and 5 of 10 asymptomatic nerves. Three of five asymptomatic nerves with high intensity were pertinent to the cases with past attack and seemed to reflect the demyelinating change. The other two nerves were pertinent to the cases without past attack and seemed to show occult lesions. We consider that STIR is useful in detection of optic nerve lesions associated with optic neuritis.

Humans↗
PubMed1990

[Effect of intraarterially injected lipiodol on rat liver with cirrhosis].

The serial histological changes of the liver following the intrahepatic arterial injection of Lipiodol in the rat with cirrhosis were investigated. The hepatocytes showed acidophilic degeneration and focal necrosis after 12 hours and restoration of focal necrosis was seen after 72 hours. Necrosis and infarction were resolved after 120 hours. We concluded that the intrahepatic arterial injection of 0.1 ml Lipiodol in the rat with cirrhosis was safely performed.

Animals↗
PubMed1990

Peripheral nerve allograft: cellular and humoral immune responses of mice.

Despite numerous experimental and clinical studies, no method has been established for achieving successful peripheral nerve allografts. One reason is that few studies concerning the immune response of the host have been conducted with nerve allografts. We therefore investigated the immune response of fresh nerve allografts with respect to both cellular and humoral immunological reactions. Using immunologically established strains of inbred mice, we performed the mixed lymphocyte culture (MLC) reaction and the cell-mediated lymphocytolysis reaction to test the cellular immune reaction and the complement-dependent cytotoxicity test to the humoral immune reaction. We observed that peripheral nerve tissues were strongly immunogenic; there was increased MLC reactivity to the allo-MHC antigen of the donor, specific cytotoxic T-cell activity, and production of specific antibody in the serum. For satisfactory nerve regeneration and transplantation, it is essential to suppress this immune response.

Animals↗
PubMed1990

Abnormal accumulation of vanadium in patients on chronic hemodialysis therapy.

Vanadium (V) has been reported to inhibit a number of enzyme activities such as those of Na(+)-K(+)-ATPase. The main excretory pathway of this element is via the kidney. These facts led us to study the V distribution in uremic patients. As a result, hemodialysis patients at our dialysis center exhibited extremely high levels of serum V (23.9 +/- 11.3 ng/ml, n = 43) as compared with healthy adults. Nondialysis patients did not show increased serum V concentrations. The V contents were significantly elevated in the skin and in the aortae of hemodialysis patients. It was found that the tap water from Kanagawa prefecture, Japan, had the highest V concentrations among the 21 cities in Japan and the US. In conclusion, oral ingestion of V-contaminated water has likely caused an accumulation of the metal in patients with end-stage renal failure.

Adult↗
PubMed1990

MR imaging of the liver before and after transcatheter hepatic chemo-embolization for hepatocellular carcinoma.

Transcatheter chemo-embolization (TCE) in hepatocellular carcinoma (HCC) was performed in 38 patients. The patients were examined by MR imaging before TCE as well as one week and 4 to 5 weeks after TCE. The tumor signal intensity in T2 weighted images increased in 13 cases and decreased in 19 cases after TCE. Increased intensity seemed to reflect intra-tumoral hemorrhage or liquefaction accompanying tumor necrosis. Decreased intensity seemed to reflect coagulation necrosis. In 9 of 18 cases followed over a 2-month period the signal intensity had decreased in both T1 and T2 weighted images. In these patients the tumor showed no recurrence at angiography and the decreased signal seemed to reflect the completion of coagulation necrosis. A hyper- and/or hypointense rim around the tumor appeared in 22 cases. These changes were thought to be perifocal edema or granulation tissue around the tumor. MR imaging was useful in evaluating the necrotic process of the tumor after TCE.

Aged↗
PubMed1990

[A case of renal hemangiopericytoma].

The patient is a 33-year-old female. On precontrast CT, the tumor shows a high density area with a low density area. On postcontrast CT, the tumor demonstrates a well-marginated low density area. Angiographically, the tumor shows a hypervascular mass with tumor vessels like a weeping willow and unhomogeneous stain. This is only the fourth such case ever reported before in Japan.

Adult↗
PubMed1990

[MRI of lymphedema using short-TI-IR (STIR)].

Thirty four cases with lymphedema of the extremities were examined with MRI at 0.5 tesla. On T1-weighted image, the enlarged subcutaneous tissue and the subcutaneous trabecular structures were seen in all cases. Moreover, the trabecular structures in the enlarged subcutaneous tissue showed low signal intensity on T1-weighted image and high signal intensity on T2-weighted image in all cases. Additionally, in 12 of 15 cases examined by Short-TI-IR (STIR) image, the trabecular structures and fluid collections in the subcutaneous tissue were shown more definitely in high signal intensity than by T2-weighted image. We consider MRI using STIR is to be useful in the evaluation of edematous disease.

Female↗