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Biomedical subjects

T Yasui

Publications and source records attributed to T Yasui.

At least 199 records · Page 11Linked to original sources
PubMed1993

[Seroepidemiological study on hepatitis C virus infection in an endemic area of hepatitis C virus].

To clarify the prevalence of hepatitis C virus infection in a rural area with high incidence of chronic liver disease in Japan, sera from 412 inhabitants, aged 20-89 years, collected in 1989-1990 and sera from 483 inhabitants in the same area, collected in 1982 were tested for anti-HCV (antibody to C100-3) with the first-generation enzyme-linked-immunosorbent-assay (ELISA). In addition, sera from 118 inhabitants, aged 20-49 years, collected in 1989-1990 were tested for HCV-RNA with the polymerase chain reaction technique, with use of primers from the 5'-untranslated region of the HCV genome. Anti-HCV was positive in 175 out of 412 sera collected in 1989-1990 (42.5%): prevalence was higher in male (54.0%) than in female (34.9%). The prevalence rates in the 20-29, 30-39, 40-49, 50-59, 60-69, and 70-89 year-old group were 0%, 14.3%, 51.9%, 41.7%, 49.1%, and 53.1%, respectively. On the other hand, in sera collected in 1982, the overall prevalence of anti-HCV was 42.5% (175 of 412). The prevalence rates in the 20-29, 30-39, 40-49, 50-59, 60-69, and 70-89 year-old group were 12.5%, 43.3%, 51.5%, 50.3%, 60.7%, and 68.9%, respectively. The prevalence rate of young adults less than 40 years old in 1982 were higher than that in 1989-1990. In short, the prevalence of hepatitis C virus infection in this area had altered a great deal. HCV-RAN was detected in 42 of 118 (35.6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Aneurysmal rupture during angiography.

The aim of the present study was to analyze the clinical data on rebleeding in cerebral aneurysms during angiography and to evaluate the importance of the time interval between the latest rupture and angiography. Fourteen personal cases and 202 patients reported in the literature are reviewed. Rebleeding during angiography occurred most often (78%) on Day O; 89% bled when angiography was performed within 6 hours of the latest rupture. The prognosis in such ruptures was poor, with a mortality of 79%. Intentional delay in angiography of at least 6 hours from the latest rupture is recommended if the associated hematoma is not large.

Adult↗
PubMed1993

Pontine hemorrhages presenting as trigeminal neuropathy--report of three cases.

Three patients with pontine hemorrhages presenting clinically as trigeminal neuropathy are described. No patient was hypertensive and angiograms were normal. Magnetic resonance (MR) imaging showed heterogeneous lesions, suggesting cavernous malformation, in one patient, but no definite diagnosis could be made in the other two patients. Such cases are rare and should be evaluated using serial MR imaging to differentiate angiographically occult vascular malformation from spontaneous hemorrhage.

Adult↗
PubMed1993

Inhibitory effects of hyaluronan on neutrophil-mediated cartilage degradation.

The effects of hyaluronan on neutrophil-mediated cartilage degradation were studied in an in vitro model. Rat peritoneal neutrophils were incubated for up to 18 h with the neutralized cartilage of bovine nasal septa using N-formyl-L-methionyl-L-leucyl-L-phenylalanine combined with cytochalasin B, or opsonized zymosan, as a stimulation agent of neutrophils. Hyaluronan inhibited the neutrophil-mediated cartilage degradation by reducing the release of sulfated glycosaminoglycans from the cartilage. Inhibitory effects were dependent on concentration and molecular weight of hyaluronan. These results suggest that hyaluronan with a high molecular weight plays an important role in protecting the articular cartilage in inflamed joints from neutrophil injury.

Animals↗
PubMed1993

[Surgical treatment of ruptured dissecting aneurysms: proximal clipping vs trapping].

The best surgical treatment for ruptured dissecting aneurysms of the vertebral artery is still controversial. Four patients (1 male, 3 female), age ranging from 43 to 62, were operated upon in our department during the last 6 years. Duration from rupture to the operation was 0 to 4 days. In 2 cases, proximal clipping was the primary treatment, while 2 had a trapping. Antiplatelet agents were given to prevent vasospasm in all cases postoperatively. In proximal clipping cases, one patient had suffered from fatal rerupture on the sixth postoperative day. In trapping cases, Wallenberg syndrome developed in one patient. These results suggest that a proximal clipping may not allow the treatment for the vasospasm because of the danger of rebleeding and also a trapped segment of vertebral artery should be as short as possible to avoid compromised perforators.

Adult↗
PubMed1993

[Neurological deterioration induced by giant intracranial aneurysms even though these aneurysms had not ruptured; mural hemorrhage and intraluminal thrombosis].

The authors report two cases of intracranial giant aneurysms inducing acute neurological deterioration even though rupture of the aneurysms had not occurred. Neurological aggravation was attributable to the acute swelling of the aneurysmal mass after intramural hemorrhage in one case, and the formation of rapid and massive intraluminal thrombosis in another case. MRI confirmed these mechanisms in both cases. MRI is very useful for demonstrating mural and intraluminal pathologies involving giant aneurysms.

Aneurysm, Ruptured↗
PubMed1993

[MR findings in traumatic cerebrospinal fluid leakage with special reference to indications of the need for dural repair].

Eleven cases of traumatic cerebrospinal fluid (CSF) leakage (8 cases of rhinorrhea and 3 cases of otorrhea) were reviewed to discuss magnetic resonance (MR) findings and surgical indications of the need for dural repair. Five patients had delayed onset of CSF rhinorrhea, 12 to 66 days (mean 28 days) after the trauma, and in the remaining 6 patients (3 rhinorrhea and 3 otorrhea) CSF leakage was noted on admission. MR study was carried out within 7 days after the onset of CSF leakage using a 0.5 tesla imager. In 7 cases of rhinorrhea, MR images demonstrated brain herniation into the ethmoid or frontal sinuses and the dural defects were repaired with the vascularized periosteum flap taken from the frontal bone or the fascia lata. In the operations, brain parenchyma was found to be plugged into the fracture line as MR images showed, and also to adhere to the margin of dural fistula. In the remaining 4 patients (without the MR findings of brain herniation into the paranasal sinuses) spontaneous cessation of CSF leakage occurred and their clinical course was good. Spontaneous cessation of CSF leakage in these cases may suggest the complete healing of the lacerated dura. However, in cases with the brain herniated into the paranasal sinuses CSF leakage may not be observed, and natural healing of the dural defect cannot be expected. Therefore, such brain herniation indicates the absolute need for dural repair even if CSF leakage is not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Reversed-phase high-performance liquid chromatography of several metal-8-quinolinethiol complexes.

The reversed-phase high-performance liquid chromatography of 8-quinolinethiol (Hqt) complexes of Fe, Co, Ni, Cu, Zn, Hg and Pb on an octadecyl-bonded silica gel stationary phase was examined. The Pb complex dissociated in the column. The retention and separation of other complexes depended on the composition of the mobile phase. EDTA as an additive displaced the Zn complex and eliminated its peak. All the other metal complexes and also Hqt and its disulphide were separated in 23 min by using methanol-water (82:18, v/v) as the mobile phase. The complexes formed by the reaction of Co(II) and Hqt gave three peaks, which were assigned as fac(S)-CoIII(qt)3, mer(S)-CoIII(qt)3 and CoII(qt)2, respectively. This method is applicable to the simultaneous determination of Fe, Co, Ni, Cu and Hg.

Chromatography, High Pressure Liquid↗
PubMed1992

Maintenance of androgen-, glucocorticoid- or estrogen-responsive growth in shionogi carcinoma 115 subline sustained in castrated mice with high dose of estrogen for 30 generations (3 years).

Shionogi carcinoma 115 (SC115), an androgen-dependent mouse mammary tumor, rapidly loses its androgen responsiveness after androgen withdrawal. The growth of this tumor can also be stimulated by high doses of estrogen or glucocorticoid. In the present study, the maintenance of hormone-responsive growth of SC115 tumors with a high dose of estrogen was examined in castrated male mice using an SC115 subline obtained by serial transplantations of SC115 tumors in estrogen-treated castrated mice for 3 years (30 generations) (subline E2). Seed tumors from both SC115 and subline E2 could rapidly grow in castrated mice given daily injections of testosterone propionate (TP), 17 beta-estradiol (E2), or dexamethasone (Dex) (100 micrograms/mouse/day) but not in those given vehicle alone. Although SC115 and subline-E2 tumors grown with TP or Dex showed temporary regression after steroid withdrawal, the tumors grown with E2 did not show such temporary regression. The TP-, E2-, or Dex-induced growth of subline-E2 tumors was almost the same as that of the original SC115 tumors. However, responsiveness to androgen, estrogen or glucocorticoid of both tumors disappeared within one passage in steroid-depleted castrated mice. The present findings demonstrate that the loss of responsiveness to androgen as well as to high doses of estrogen or glucocorticoid of SC115 tumors can be prevented in castrated mice not only with androgen but also with high doses of estrogen.

Animals↗
PubMed1992

Inhibitory effects of hyaluronan on [14C]arachidonic acid release from labeled human synovial fibroblasts.

The effects of hyaluronan (HA) on the release of arachidonic acid (AA) from phospholipids induced by bradykinin in synovial fibroblasts of osteoarthritic patients were examined. HA inhibited [14C]AA release from prelabeled synovial cells stimulated with and without bradykinin 1 hr after incubation with HA and thereafter. The inhibitory effects of HA on [14C]AA release were dependent on the concentration and molecular weight of HA. However, inhibition of [14C]AA release by HA was not merely due to the viscosity of HA. The [14C]AA release induced by calcium-ionophore A23187 was also inhibited by HA with a high molecular weight. In addition, HA did not affect [14C]AA uptake by the cells. Our results suggest that HA with a high molecular weight elicits anti-inflammatory effects, at least in part, by inhibiting AA release in inflamed joints.

Arachidonic Acid↗
PubMed1992

Significance of gadolinium-enhanced magnetic resonance imaging in differentiating spinal cord radiation myelopathy from tumor. Case report.

A young woman with a fourth ventricular ependymoma underwent radiotherapy following tumor excision. Twenty months later she developed a progressive neurological deficit at the C-2 vertebral level. Gadolinium-enhanced magnetic resonance imaging, showed an intramedullary lesion at the C-2 level. Although radiation myelopathy was suspected, tumor recurrence could not be excluded. Re-exploration and histopathology both confirmed a diagnosis of radiation myelopathy. A retrospective review of the case indicated findings favoring radiation myelopathy. The pertinent literature is reviewed and the findings discussed.

Adult↗
PubMed1992

[Ischemic complications following parent artery occlusion with detachable balloons in the treatment of large carotid aneurysms: effectiveness of 99mTc-HMPAO SPECT and importance of postoperative management].

Three patients with large carotid aneurysms were treated by parent artery occlusion with detachable balloons. Of these, 2 had intracavernous carotid artery aneurysms and one had a carotid-ophthalmic aneurysm. All patients underwent a formal balloon occlusion test and tolerated it well. One patient with a carotid-ophthalmic aneurysm, however, developed postoperative ischemic effects. This case was that of a 55 year-old female with right visual disturbance. Her middle cerebral artery flow had been compromised during test occlusion under induced hypotension. Although initially intact after balloon occlusion, she was found to be hemiplegic 24 hours later. She subsequently developed multiple small infarcts which were shown on MRI and which corresponded exactly to the previously demonstrated region of decreased flow during testing. This ischemic complication is possibly due to hypoperfusion, but embolism from the thrombosed aneurysm can not be denied. To prevent these complications, an extracranial-intracranial artery anastomosis prior to parent artery occlusion should be considered if the preoperative 99mTc-HMPAO SPECT shows a compromised cerebral blood flow. In addition to this, postoperative anticoagulant therapy should be given even if test occlusion was well tolerated clinically.

Brain Ischemia↗
PubMed1992

[Antitumor effect of liposome-entrapped carboplatin after intraperitoneal administration in rats].

We examined the distribution in tissue and antitumor effects of freeze-dried liposome-entrapped carboplatin (Lipo-CBDCA) after intraperitoneal administration to rats bearing AH 130 tumors. Liposomes composed of egg lecithin and cholesterol were used as drug carriers. The serum concentration of platinum was decreased for a short time after the intraperitoneal administration of Lipo-CBDCA. After at least 3 hours, the serum concentration of platinum was higher with free CBDCA intraperitoneal or intravenous administration. The antitumor effects of Lipo-CBDCA were determined in rats with peritoneal dissemination due to AH 130 tumors. Intraperitoneal Lipo-CBDCA prolonged the life span of the tumor-bearing rats. No side effects of the chemotherapy were demonstrated in biochemical and histological studies in the liver, kidney, spleen and small intestine. These results indicate that intraperitoneal chemotherapy with Lipo-CBDCA may be more effective than that with free CBDCA managing in peritoneal dissemination, and may be therapeutically useful without toxic side effects.

Animals↗
PubMed1992

[Efficacy of preoperative adjuvant chemotherapy using adriamycin targeting the regional lymph nodes for gastric cancer--lymph node-targeting delivery of adriamycin in rabbits].

Chemotherapy targeting the regional lymph nodes for gastric cancer may be more effective preoperatively than postoperatively since anticancer drugs can be transported to the regional lymph nodes via the lymphatic flow through the stomach. Distribution of Adriamycin (ADR) among the various organs was assessed following its intravenous injection in rabbits. The delivery index of the drug to each organ was assessed by the ratio of the area under the concentration-time curve (AUC) of each organ to the AUC of the regional lymph nodes following the intravenous administration. The delivery index was 0.14 for the stomach, 0.11 for the heart, 0.53 for bone marrow, 0.74 for the spleen, and 0.14 for the liver. These data suggest that preoperative adjuvant chemotherapy by intravenous administration of ADR may be effective in targeting ADR at the regional lymph nodes. Tissue ADR concentrations in the regional lymph nodes were assessed following gastric submucosal administration of ADR in rabbits. The targeting index for the regional lymph nodes was 8.20, measured by the ratio of AUC following a gastric submucosal injection to AUC after the intravenous injection of ADR. This suggests that it may be possible to selectively target chemotherapy to regional lymph nodes by employing a gastric submucosal administration of ADR.

Animals↗
PubMed1992

[Therapeutic occlusion of unilateral vertebral artery for unclippable aneurysms; special reference to postoperative brainstem ischemia].

Seven cases of unclippable vertebral artery aneurysms (3 dissecting, 1 fusiform, 2 saccular and 1 giant) are reported. Five of these had subarachnoid hemorrhage, one showed mass effect and the other was found incidentally. Trapping of the involved portion of the vertebral artery was performed in 4 cases, proximal clip occlusion in 2 and proximal balloon occlusion in 1. There were no operative deaths and no rebleeding, but brainstem ischemia developed in 4 cases, two being transient and two permanent. The ischemic complications were possibly due to; (a) hypoperfusion in the transient cases and (b) thromboenbolism, from the partially thrombosed giant aneurysm or thrombosis of the cul-de-sac vertebral artery, in the permanent ones. Preoperative temporary vertebral artery occlusion with an inflatable balloon or postoperative anticoagulant therapy should be considered in the management protocol.

Aortic Dissection↗