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Biomedical subjects

Y Oda

Publications and source records attributed to Y Oda.

At least 541 records · Page 30Linked to original sources
PubMed1989

[Partially thrombosed radiculomeningeal arterio-venous fistula in spinomedullary junction].

A 58-year-old man was admitted to our hospital because of tetraparesis of fairly sudden onset. He had had difficulty in miction since 6 months earlier. MRI study showed a high intensity area in front of the medulla and a low intensity "vessel-like" shadow in front of the upper cervical region on T1-weighted image. The dorsal part of the medulla and cervical spinal cord showed diffuse low intensity signals in T1-weighted image. The intra-axial lesion appeared as high intensity signals in T2-weighted image. Angiography revealed a huge dilated vascular malformation fed by a third part of the right vertebral artery. The lesion in front of the medulla was not opacified. His neurological status progressively deteriorated, resulting in combined respiratory distress. Emergency surgery was performed only for posterior decompression. Although postoperative balloon catheterization was scheduled, he died of gastric perforation and pancreas necrosis one month after the operation. At the autopsy, it was found that the feeding artery of the AVM was branched from the junction of V3 and V4 of the right vertebral artery, where the artery penetrates the dura mater. The meningeal artery was engorged, and the radicular vein of C1 was markedly dilated due to the retrograde filling. The premedullary vessel was thrombosed, but the cervical part of the AVM showed eccentric hypertrophy of the wall and a partially organized thrombus. Intra-axially, the posterior funiculus was markedly destroyed and the spinal cord was edematous and subnecrotic.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Angiography↗
PubMed1989

Isolated Schwann cells can synthesize the basement membrane in vivo.

The purpose of the present study is to examine whether isolated Schwann cells that are not in contact with axons can synthesize the basement membrane in vivo. Schwann cells obtained from sciatic nerve of neonate Wistar rats were prepared in culture, harvested, and mixed with collagen matrix. The silicone tube filled with the collagen matrix containing Schwann cells was closed by a Millipore membrane at both ends to isolate the interior from the outer environment and was implanted in a gap between proximal and distal stumps of transected sciatic nerve of an adult Wistar rat. Ten days later, the implanted silicone tube was prepared for electron microscopic observations. Schwann cells in the tube were elongated longitudinally and lined up parallel to the proximo-distal direction. No regenerating axons penetrated the Millipore membrane into the tube. The basement membrane showing almost normal structure was produced on the surface of the Schwann cells. While the silicone tube was placed side by side to the intact sciatic nerve, Schwann cells in the tube were scattered and no basement membrane was observed. These results suggest that some humoral factors might be released from the transected nerve stumps, which may be responsible for the regular arrangement and the basement membrane formation by Schwann cells without any contact with axons.

Animals↗
PubMed1988

Lymphangiosarcoma in postmastectomy lymphedema (Stewart-Treves syndrome): ultrastructural and immunohistologic characteristics.

Two cases of lymphangiosarcoma arising in a chronic lymphedematous extremity following mastectomy (Stewart-Treves syndrome) were reported with not only standard histology, but also special study on the ultrastructure and immunohistology. These cancers developed as a result of chronic lymphedema of the involved limb following mastectomy 15 and 16 years ago, respectively, for breast carcinoma. Immunohistologic and electron microscopic examinations proved that this tumor originates in the vascular endotheliocytes, even though they are clinically chronic lesions apparently derived from the lymphatic vessels. This sarcoma develops multicentrically in an edematous arm and spreads out rapidly, so prognosis is quite discouraging in those patients. They need to be radically surgically treated without hesitation; hence, amputation, not limb-saving surgery, should be indicated.

Adenocarcinoma, Scirrhous↗
PubMed1988

Immunohistochemical studies on the tissue localization of collagen types I, III, IV, V and VI in schwannomas. Correlation with ultrastructural features of the extracellular matrix.

The distinctive tissue localization of collagen types in typical schwannomas with Antoni type A and B areas was demonstrated immunohistochemically using affinity-purified antibodies against types I, III, IV, V and VI collagen and comparative ultrastructural studies were made on the extracellular matrix components. Antoni type A tissue, which was composed of tightly packed spindle cells with long cytoplasmic processes surrounded by a continuous basement membrane and a few fibrillar components of the extracellular matrix, was almost exclusively immunoreactive for type IV collagen, presumably representing the basement membrane. Verocay bodies, which are organoid structures of Antoni type A tissue, had a variety of more abundant extracellular fibrous components, such as banded collagen fibrils, fibrous long-spacing fibrils and microfibrils. These were positive for type I and III, as well as type IV collagen. In Antoni type B areas, where two types to tumor cells designated Schwann cell-like and fibroblast-like were scattered in large amounts of amorphous extracellular matrix containing microfibrils and thick banded collagen fibrils, type VI collagen as well as types I, III and IV collagen were consistently detected. Type V collagen was localized in dense fibrous tissue areas and around blood vessels. These findings indicate that the differently organized cellular patterns of schwannomas, identified as Antoni types A and B, are characterized not only by the ultrastructural features of the extracellular matrix, but also by the distinctive collagen types produced by neoplastic Schwann cells.

Adult↗
PubMed1988

Harman and norharman induce SOS responses and frameshift mutations in bacteria.

Norharman and harman, beta-carboline derivatives with comutagenic activity in Salmonella typhimurium, were examined for their activity to induce SOS responses in S. typhimurium using the umu-test and mutations in Escherichia coli. The inducibility of the umuC gene by norharman and harman was assayed by measuring the levels of beta-galactosidase activity in tester cells harbouring the umuC'-'lacZ fusion gene on a plasmid. In the umu-test, both norharman and harman weakly induced umuC gene expression at 25-100 and 50-150 micrograms/ml, respectively. In the mutation test using reversion from trpE9777 to Trp+, harman was relatively more potent than norharman in inducing the mutations. These results indicate that norharman and harman induce SOS responses as well as reversion of trpE9777 frameshift mutation in bacteria.

Alkaloids↗
PubMed1988

Dependency on light and vitamin A derivatives of the biogenesis of 3-hydroxyretinal and visual pigment in the compound eyes of Drosophila melanogaster.

When the fruitfly, Drosophila melanogaster, was reared on media deficient in carotenoids and retinoids, the level of 3-hydroxyretinal (the chromophore of fly rhodopsin) in the retina decreased to less than 1% compared with normal flies. The level of 3-hydroxyretinal increased markedly in flies that were given a diet supplemented with retinoids or carotenoids. The retinas of flies fed on all-trans retinoids and maintained in the dark predominantly contained the all-trans form of 3-hydroxyretinal, and showed no increase in the level of either the 11-cis isomer or the visual pigment. Subsequent illumination of the flies converted substantial amounts of all-trans 3-hydroxyretinal to its 11-cis isomer. The action spectrum of the conversion by illumination showed the optimum wavelength to be approximately 420 nm, which is significantly greater than the absorption maximum of free, all-trans 3-hydroxyretinal. Flies that were fed on carotenoids showed a rapid increase of the levels of 11-cis 3-hydroxyretinal and of visual pigment in the absence of light.

Animals↗
PubMed1988

Expression of glial fibrillary acidic protein (GFAP) in peripheral nerve sheath tumors. A comparative study of immunoreactivity of GFAP, vimentin, S-100 protein, and neurofilament in 38 schwannomas and 18 neurofibromas.

Immunoreactivity of glial fibrillary acidic protein (GFAP) in 38 schwannomas and 18 neurofibromas was evaluated and compared with the reactivity of vimentin, S-100 protein, and neurofilament protein. All cases were positive for vimentin and S-100 protein. GFAP was positively stained in the neoplastic cells of 15 of 38 schwannomas (38%) and in two of 18 neurofibromas (11%). The extensively stained GFAP-positive tumors tended to be deeply situated in the body. The GFAP-positive cells were usually spindle-shaped and appeared preferentially in the perivascular region of hyalinized, thick blood vessels.

Adolescent↗
PubMed1988

Spinal arteriovenous malformation: MR imaging.

Ten patients with spinal arteriovenous malformations (AVMs) were examined with high-field-strength (1.5-T) magnetic resonance (MR) imaging and a surface coil (eight patients) or head coil (two patients). Four AVMs were intramedullary, and six were extramedullary. There was one case of Foix-Alajouanine disease (subacute necrotizing myelitis; thrombosed AVM). Three important pathologic findings--myelomalacia, total thrombosis, and wall thickening of the draining vein--were clearly demonstrated at MR imaging and confirmed at autopsy. A flow-sensitive sequence was valuable in the depiction of one intramedullary AVM as hyperintense, the postoperative evaluation of AVM, and the differentiation of nidus from old intramedullary hematoma. In other AVMs, cord edema, periradicular hematoma, and reversible changes of cord scalloping after surgery were demonstrated. MR imaging demonstrated various pathologic changes of the spinal cord that could not be detected with any other imaging method.

Adult↗
PubMed1988

Insulin resistance in a boy with congenital generalized lipodystrophy.

We have studied insulin resistance in a 12-year-old Japanese boy who presented with congenital generalized lipodystrophy. Oral glucose tolerance test exhibited a diabetic pattern with normal fasting plasma glucose. Results from euglycemic glucose clamp study showed decreases in both insulin sensitivity and responsiveness. Both the patient's erythrocytes and Epstein-Barr virus transformed lymphocytes showed low-normal insulin binding with a slight reduction in binding affinity in the latter. Insulin binding to the cultured fibroblasts was decreased due to a lowered affinity. In addition, they displayed a rightward shift of the insulin dose-response curve for D-14C-glucose uptake with no decrease in the maximum uptake. Insulin-stimulated autophosphorylation and kinase activity of the wheat germ agglutinin purified receptors from the Epstein-Barr virus-transformed lymphocytes appeared normal. The reason for some discrepancies in insulin binding among the cells remains unknown, and we cannot formulate a conclusion as to whether or not a primary binding defect of insulin receptors exists and contributes to insulin resistance in the patient. The decrease in insulin responsiveness demonstrated in the glucose clamp study may result from a defect at the rate-limiting step in the postbinding process of insulin action, presumably a defect in the glucose transport system in muscle tissues. The defect may be secondary to changes in in vivo circumstances.

Cell Line, Transformed↗
PubMed1988

Central venous pressure and plasma Na concentration during drinking behavior in the dehydrated dog.

Changes in circulating blood volume, plasma Na concentration, and central venous pressure (CVP) after fluid intake were monitored continuously in water-deprived dogs. When dogs were allowed free access to fluid (tap water or 0.9% saline), rapid satiation appeared before any systemic changes in blood composition took place, and CVP increased remarkably (about 6 mmHg) in association with drinking behavior. The possible roles of CVP as a controlling factor of drinking were hypothesized.

Animals↗
PubMed1988

Optimal therapeutic regimen of famotidine based on plasma concentrations in patients with chronic renal failure.

An oral therapeutic regimen of famotidine, a histamine H2-receptor antagonist, was evaluated in patients with chronic renal failure who were receiving dialysis three times a week. Measurements of the half-life, bioavailability, and dialysis elimination rate were performed. The half-life of famotidine after oral administration in patients with renal failure was 22.5 hours as opposed to 2.5 hours in control subjects: after intravenous injection, it was 14.6 hours as compared with 2.2 hours. The bioavailability after oral administration was 49.4% in patients with renal failure and 55.2% in control subjects. The dialysis elimination rate was stable and independent of its plasma level, with an average of 41.9%. The oral administration of famotidine (20 mg) immediately after dialysis (60 mg/week) was found optimal and safe. There were no significant side effects with this regimen.

Adult↗
PubMed1988

[Treatment of vasospasm after ruptured cerebral aneurysms by 'pellet-cisternal-drain: PCD' containing sustained-release vasodilators].

Diltiazem or papaverine hydrochloride as vasodilators were polymerized with silicon polymer (MDX-4-4210: Dow Co.). The silicon pellets containing the drugs were placed in cisternal drainage tubes made of silicon, and used for the continuous cisternal drainage after the operations of ruptured cerebral aneurysms. This system was tentatively termed 'pellet-cisternal-drain; PCD'. The rate of diffusion of the drug from the pellets was examined in 30 patients who underwent surgery for ruptured cerebral aneurysms in the acute phase on the 0-4th postical days. 73.3% of patients had severe subarachnoid hemorrhage as group 3-4 in Fisher's classification in CT scan. The concentration of either drug in the cerebrospinal fluid on the 2nd to 3rd postoperative days reached the level of the maximum concentration obtained after bolus injection, and the level on the 5th to 10th postoperative days was similar to that observed several hours after bolus injection. The data showed that the sustained release pellet can act as a vasodilator, and its effects on cerebral vessels after an episode of subarachnoid hemorrhage continue for 2 to 3 weeks. All patients except one showed excellent results and returned to normal life.

Adult↗