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Biomedical subjects

Y Kotoura

Publications and source records attributed to Y Kotoura.

At least 73 records · Page 4Linked to original sources
PubMed1989

Instrumentation surgery for primary tumors of the spine.

We performed instrumentation surgery on ten patients with the following rare primary spinal tumors; three solitary plasmacytomas, an aneurysmal bone cyst, a chordoma, a giant-cell tumor, a hemangioma, a solitary bone cyst, a benign osteoblastoma, and a chondrosarcoma. These tumors were found in the cervical spine (one case), thoracic spine (five cases), lumbar spine (two cases), and sacrum (two cases). The patients consisted of five men and five women, and their average age was 43.1 years. Harrington instrumentation was used in six cases, Zielke instrumentation in two, a combination of both in one case, and a Kirshner wire in one. In two cases, iliolumbar fusion was performed with Harrington instrumentation, after total resection of the sacrum. Average duration of the follow-up period was 5 years. This report describes these rare cases and emphasizes the effectiveness of instrumentation surgery in the reconstruction of the spine after extensive surgery.

Adult↗
PubMed1989

SPECT images using 99mTc(V)-DMS in lung metastasis of osteosarcoma.

Color images of single-photon emission computed tomography (SPECT) using technetium-99m(V) dimercaptosuccinic acid (99mTc(V)-DMS) were demonstrated in a patient with lung metastases from osteosarcoma. SPECT image using 99mTc(V)-DMS could be useful for the detection of lung metastasis from osteosarcoma.

Adult↗
PubMed1989

In vivo measurement of anodic polarization of orthopaedic implant alloys: comparative study of in vivo and in vitro experiments.

A new system of single piece electrodes was applied to in vivo and in vitro measurements of anodic polarization of several alloys used in orthopaedic implants. The tested surface was scrutinized with a stereomicroscope after each experiment. This confirmed pit formation and excluded the possibility of other sudden increase of anodic current such as crevice corrosion and oxidation or reduction of organic substances. The results were reproducible. Although there were certain differences between the results obtained in the two conditions, the order of corrosion resistances of alloys was consistent.

Alloys↗
PubMed1989

Results of distal splenorenal shunt with versus without splenopancreatic disconnection.

From December 1973 to December 1987, we performed a distal splenorenal shunt (DSRS) in 112 cases of portal hypertension, including 107 with postnecrotic liver cirrhosis and 5 with idiopathic portal hypertension (IPH). They comprised about 50% of our surgical cases with esophageal varices. In 1981, we modified our operative procedure towards a more extended splenopancreatic disconnection (SPD) in order to prevent the "stealing" of the shunt through the pancreatic vein. In one group of 69 patients who underwent DSRS alone, the operative mortality was 2.9%; postoperative encephalopathy was seen in 17.4%, late hepatic failure in 40.6%, and recurrence of varices in 4.3%. In the other group, 43 patients who underwent DSRS with SPD, there were no operative deaths, no encephalopathy (better than DSRS alone at p less than 0.05), and late hepatic failure was seen in only 9.3% (better than DSRS alone at p less than 0.025), while the recurrence rate of 7% was the only statistical increase. These data show that DSRS + SPD can improve chances of survival.

Collateral Circulation↗
PubMed1989

Bone bonding behavior of bead-coated alumina ceramic under load-bearing conditions.

Alumina ceramic has good biocompatibility, high mechanical strength, and excellent lubrication properties. However, it is bioinert and does not bond with bone tissue. Therefore, to promote mechanical bonding, we have developed an alumina ceramic material coated with alumina ceramic beads using identical alumina ceramic binder. In this study, we evaluated the bone bonding capability of this material under load-bearing conditions along with its mechanical properties. The test pieces with or without bead-coating were implanted into the load-bearing portions of the medial and lateral femoral condyles of adult mongrel dogs. The dogs were euthanized 4, 8, and 24 weeks after implantation, and the pull-out test and histological examination were performed. The uncoated implants showed signs of loosening similar to those observed clinically. In contrast, the bonding strength of the bead-coated implants was significantly greater than that of the uncoated implants and increased with implantation time. This increase in strength differs from the results obtained in the non-load-bearing experiments, in which a plateau was seen relatively early after implantation. Results of histological examination suggested that this increase was caused by thickening of ingrown trabeculae, which could be observed as early as 4 weeks after implantation, at the bone-implant interface. In addition, the mechanical properties of the bead-coated alumina ceramic were comparable to those of grooved alumina ceramic which has been used clinically. These results indicate the possibility for clinical application of the bead-coated alumina ceramic.

Aluminum↗
PubMed1989

Portal and mesenteric venous thrombosis as a complication of endoscopic sclerotherapy.

We report on the occurrence of portal and mesenteric venous thrombosis in two patients who underwent endoscopic injection sclerotherapy (EIS) for bleeding esophageal varices. One patient was diagnosed at autopsy, and portal and mesenteric venous thrombosis was not suspected during life. The second patient was suspected on ultrasound examination and was diagnosed by angiography. In the second case, therapy was effective and symptoms disappeared. He was treated by a distal splenorenal shunt after he had stabilized for 1 month. During the operation, no evidence of mesenteric infarction was found. The venous phase of the superior mesenteric arteriogram 1 month after surgery revealed an organized thrombosis in the right intrahepatic portal branches. No other thrombi were seen. This patient is the first reported who has survived portal and mesenteric venous thrombosis after sclerotherapy.

Aged↗
PubMed1989

1 alpha,25(OH)2D3 exerts cytostatic effects on murine osteosarcoma cells and enhances the cytocidal effects of anticancer drugs.

The effects of 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25-(OH)2D3), 1 alpha-hydroxyvitamin D3 (1 alpha(OH)D3), and dexamethasone on colony formation of Dunn osteosarcoma cells (TA 102 cells) were investigated. Concentrations of 1 alpha,25(OH)2D3, 1 alpha(OH)D3, and dexamethasone at which they exerted 50% reduction of the total area of TA 102 colony formation were 9 X 10(-9) M, 9 X 10(-8) M, and 5 X 10(-6) M, respectively. Effects of anticancer drugs on TA 102 cells were also investigated and concentrations needed for 50% growth inhibition (50% inhibitory concentration values) of cis-platinum, mitomycin C (MMC), methotrexate (MTX), and Adriamycin (ADR) against TA 102 cells were calculated to be 0.07 microgram/ml, 0.0008 microgram/ml, 0.0008 microgram/ml, and 0.0005 microgram/ml, respectively. The simultaneous treatment of TA 102 cells with 10(-8) M of 1 alpha,25(OH)2D3 and anticancer drugs significantly enhanced the respective inhibitory effects on colony formation. In this treatment, the IC50 value of MMC was calculated to be 6.4 X 10(-6) micrograms/ml, which was 1/160 of the expected IC50 value of MMC (8 X 10(-4) micrograms/ml). Similar synergistic effects were observed when the cells were treated with 1 alpha,25(OH)2D3 and low concentrations of cis-platinum, MTX, or ADR.

Animals↗
PubMed1989

Severe hemolysis after distal splenorenal shunt.

We report a case of severe hemolysis after distal splenorenal shunt. Hemolysis was suddenly recognized at the time splenorenal venous anastomosis was completed, and it continued on the operative day and the first postoperative day. After the shunt, the intraoperative splenic venous blood flow was approximately double its previous level, as measured by electromagnetic flowmeter. Angiographic partial splenic embolization was performed on the second postoperative day, and then hemolysis stopped suddenly. This suggested that hemolysis after distal splenorenal shunt was related to increased splenic blood flow and acceleration of erythrocyte destruction.

Hemoglobinuria↗
PubMed1988

Chromosomal reorganization for the expression of recessive mutation of retinoblastoma susceptibility gene in the development of osteosarcoma.

Recent evidence indicates that the mutation of retinoblastoma susceptibility (RB) gene is also involved in the development of osteosarcoma. We studied 30 cases of osteosarcoma for the structural anomalies of the RB gene by Southern hybridization analysis with cDNA probes of the RB gene. Thirteen cases (43%) showed structural anomalies of the RB gene. They included the total or partial deletion, or rearrangement of the RB gene; seven with homozygous deletions and six with hemizygous deletions or rearrangements. By the use of restriction fragment length polymorphism fragments as chromosome markers, those seven tumors having homozygous deletions and four of six tumors having hemizygous anomalies showed the loss of heterozygosity at other loci on chromosome 13. Among those tumors with no apparent structural changes of the RB gene, seven cases showed the loss of heterozygosity on chromosome 13, and altogether the loss of heterozygosity by either homozygosity or hemizygosity was found in 18 (64%) of 28 informative cases. The loss of heterozygosity was also found for nine of 10 other chromosomes, of which chromosome 17 showed the highest frequency (77%). The tumors with loss of chromosome 13 alleles also showed additional losses of alleles on other chromosomes, while tumors retaining heterozygosity of chromosome 13 also retained heterozygosity at the informative loci on other chromosomes. Southern hybridization and karyotype analysis in some selected cases suggest that the concerted loss of heterozygosity at multiple loci may be a consequence of the polyploidization-segregation process.

Adolescent↗
PubMed1988

Apatite-wollastonite containing glass ceramic-fibrin mixture as a bone defect filler.

The purpose of this study was to evaluate the usefulness of a mixture of apatite-wollastonite containing glass ceramic (A-W.GC, 42-60 mesh in granule size) with fibrin as a bone defect filler. A bone defect was drilled in the proximal metaphysis of the rat tibia and was filled with (1) fibrin glue, (2) A-W.GC granules, or (3) A-W.GC-fibrin mixture. Nothing was placed in the defect of the controls. The animals were serially sacrificed until 8 weeks after the operation, and the defect site was histologically examined and histomorphometrically analyzed for quantitative evaluation of newly formed bone and blood vessels. The use of fibrin glue as the binder markedly increased the ease of handling the A-W.GC granules. In the controls, little trabecular regeneration was observed in the defect site. Early vascularization (confirmed by microangiography) increased and the repairing process was accelerated in the defects filled with fibrin. In these defects filled with A-W.GC granules, good bone formation was observed around the granules. Bone formation was accelerated in the defects filled with A-W.GC fibrin mixture. Thus, the mixture showed good osteoconductive potential as well as acceleration of the repair process. Therefore, A-W.GC-fibrin mixture is considered to be a useful bone defect filler.

Animals↗
PubMed1988

Intraspinal epidermoid and dermoid cysts. Surgical results of seven cases.

Seven cases of intraspinal inclusion cysts, surgically treated between 1970 and 1984, are reported in this paper. Four were epidermoid cysts and three dermoid. Two cysts were located in the thoracic spine (one dermoid and one epidermoid) and five in the lumbosacral region (three epidermoid and two dermoid). Associated spinal dysraphia was noted in five cases. Congenital dermal sinus was found in two cases, spina bifida cystica in one, spina bifida occulta in one, and diastematomyelia in one case. The average postoperative follow-up period was 5 years. No neurological symptoms were found in the five patients who received early surgical treatment, but for the two patients whose operations were late, there were some residual neurological deficits. Therefore, early and accurate diagnosis and radical surgical extirpation are emphasized.

Adult↗
PubMed1988

Follow up studies on various reconstruction methods of the biliary tract including our new method (Roux Y-duodenojejunal anastomosis).

Thirty six patients with benign diseases of the biliary tract (14 patients with congenital choledochal dilatation, 15 patients with postoperative stricture and 7 patients with others) were divided into three groups: 21 patients who underwent a Roux Y (RY), 7 patients who underwent a jejunal interposition (IP) and 8 patients who underwent a side to side anastomosis between the jejunal limb of the Roux Y and the duodenum (RY-DJ). The RY-DJ was designed to decompress the Roux Y jejunal limb and to allow an inflow of bile into the duodenum. Significant complications, including cholangitis, infection, or abdominal pain, developed in 10 of the patients with RY (48 per cent), 7 of the patients with IP (100 per cent) and 1 of the patients with RY-DJ (13 per cent). None had a postoperative peptic ulcer. Simultaneous scintigraphy showed the time required for the two agents, 99mTc-IDA and 111In-DTPA, to mix at the upper jejunum, which revealed that the time taken by the patients with RY-DJ was similar to that of the patients with IP and to that of healthy controls. The time was markedly longer in the patients with RY, presumably due to a prominent stasis of the bile tracer in the Roux Y jejunal limb. Our new method (RY-DJ) for reconstruction of the extrahepatic biliary tract is more physiological and has less postoperative complications than other conventional methods.

Adolescent↗
PubMed1988

Scintigraphic evaluation of two cases with alveolar soft part sarcoma.

Two cases of alveolar soft part sarcoma were examined with gallium-67 citrate (67Ga), technetium-99m-methylenediphosphate (99mTc-MDP) and technetium-99m(V)-dimercaptosuccinic acid (Tc(V)-DMS) to compare the sensitivity of these three radiopharmaceuticals. All scintigrams were positive with primary tumor, and images with Tc(V)-DMS were the best. Skull metastasis could be also detected by all agents, but scintigrams with lung metastases were negative. In scintigraphic evaluation of alveolar soft part sarcoma, Tc(V)-DMS may be a better agent than 67Ga or 99mTc-MDP.

Adult↗
PubMed1988

Uptake of 99Tcm-MDP in lung metastasis from osteosarcoma: clinical and animal studies.

Bone scintigraphy was performed in 17 patients with previously known lung metastases of osteosarcoma. 99Tcm-MDP uptake was observed in all primary bone lesions but lung metastatic lesions were positive in only six patients (35%). 99Tcm-MDP uptake by lung metastases was significantly correlated with bone and osteoid formation in the metastatic lesions and preoperative serum ALPase values. These clinical observations were confirmed by using nude mice transplanted with human lung metastatic osteosarcoma. 99Tcm-MDP scintigraphy appears to be useful for detecting lung metastases of osteosarcoma only in a selected group of patients.

Adolescent↗
PubMed1988

Relationship between in vitro binding activity and in vivo tumor accumulation of radiolabeled monoclonal antibodies.

The relationship between in vitro cell binding and in vivo tumor accumulation of radiolabeled antibodies was studied using 125I- and 111In-labeled monoclonal antibodies to human osteosarcoma, and a human osteosarcoma xenograft (KT005) in nude mice. Three monoclonal antibodies--OST6, OST7, and OST15--raised against human osteosarcoma recognize the same antigen molecule. Although the binding of both 125I- and 111In-labeled OST6 to KT005 cells was higher than that of radiolabeled OST7 in vitro, 125I-labeled OST6 showed a faster clearance from the circulation and a lower accumulation in the transplanted tumor than 125I-labeled OST7. In contrast to the radioiodinated antibodies, the in vivo tumor accumulation of 111In-labeled OST6 was higher, although not significantly, than that of 111In-labeled OST7. OST15 showed the lowest binding in vitro, and its in vivo tumor localization was also lower than the others. The discrepancy in tumor uptake between OST6 and OST7 labeled with either 125I or 111In may have been a result of differing blood clearance. These results suggest that binding studies can be used to exclude from in vivo use those antibodies which show very poor binding in vitro, while in vivo serum clearance may be a better test for choosing antibodies with similar binding.

Animals↗
PubMed1988

[Improvement of selectivity of distal splenorenal shunt and its clinical analysis].

Follow up studies of 96 patients who underwent distal splenorenal shunt (DSRS) were performed and the loss of selectivity of DSRS was evaluated. We have established the indications for DSRS since 1980 and modified the procedures for DSRS--complete or incomplete splenopancreatic disconnection of the splenic vein (SPD)--since 1981. Twenty two of 47 patients operated before 1980 and 9 of 49 patients operated after 1980 were died of liver failure, being statistically significant (p less than 0.05). There were no significant differences in the incidence of development of encephalopathy before and after 1980 (7 patients before 1980 and 6 patients after 1980). Twenty eight of 69 patients without SPD and one of 16 patients with incomplete SPD were died of liver failure, being statistically significant (p less than 0.025). Twelve of 69 patients without SPD developed encephalopathy, while none of 27 patients with complete or incomplete SPD developed encephalopathy (p less than 0.05). It was suggested, therefore, that our established indications and DSRS with complete or incomplete SPD might be suitable for the selective shunt operation for esophageal varices.

Esophageal and Gastric Varices↗