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Biomedical subjects

T Oku

Publications and source records attributed to T Oku.

At least 73 records · Page 4Linked to original sources
PubMed1996

Perivascular coating with fibrin glue of cerebral arteries in patients with aneurysmal subarachnoid hemorrhage; incidence of chronic hydrocephalus.

The incidence of chronic hydrocephalus was studied in 39 patients with subarachnoid hemorrhage, who underwent perivascular coating with fibrin glue of cerebral arteries after clipping of aneurysm. A use was made of this procedure in order to prevent vasospasm by keeping the main cerebral arteries away from direct contact with subarachnoid clots. Most cases in this series belonged to group 3 of Fisher's CT grade (33/39, 84.6%). As a result, despite the high CT grade, the incidence of chronic hydrocephalus was as low as 17.9% (7/39), almost in agreement with those of the previous literature. In conclusion, (1) coating with fibrin glue did not increase the incidence of chronic hydrocephalus and (2) intrathecal application of fibrin glue is a promising method in the field of clinical neurosurgery.

Adhesives↗
PubMed1996

Anomalous internal carotid artery-anterior cerebral artery anastomosis associated with fenestration and cerebral aneurysm.

A 69-year-old female presented with a ruptured aneurysm at the distal tip of a fenestrated anomalous artery which originated in the ophthalmic segment of the internal carotid artery (ICA), passed between the optic nerves, ascended along the midline, and formed the fenestration before dividing into the bilateral pericallosal arteries. The anomalous artery manifested as subarachnoid hemorrhage. Four days later, she died from severe pulmonary edema. The angiographic finding was confirmed by postmortem examination. Numerous perforating vessels from the anomalous artery and the distal ICA supplied the optic nerves and chiasm. This finding supports the idea that this anomalous vessel may be an extreme developmental variation of the prechiasmal arterial plexus.

Adult↗
PubMed1996

[Randomized controlled study on adjuvant immunochemotherapy with carmofur (HCFU) for noncuratively resected and unresected gastric cancer].

To evaluate the efficacy of adjuvant immunochemotherapy, especially the long-term administration of HCFU to patients with noncuratively resected and unresected gastric cancer, a randomized controlled study was conducted by 16 institutions in Hokkaido. After surgery, 185 patients were divided into two groups using the envelope method; group A (84 patients) treated by MMC (4 mg, twice a week, total 1 mg/kg)+OK-432 (or PSK): group B (101 patients) treated with MMC+OK-432+HCFU (600 mg, per day). The 5- and 10-year survival rates were 9.8 and 3.1% in group A, and 11.1 and 11.1% in group B (p=0.062). Better survival rates were obtained in those cases with unresected, S3, or peritoneal dissemination in group B. These results suggested the long-term administration of HCFU was effective for noncuratively resected and unresected gastric cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Inhibition by galloylglucose (GG6-10) of tumor invasion through extracellular matrix and gelatinase-mediated degradation of type IV collagens by metastatic tumor cells.

Tumor invasion into extracellular matrix (ECM) and basement membrane (BM) is a crucial step in the complex multistage process that leads to metastasis formation. GG6-10 galloylglucose, isolated from Galla Rhois, inhibited the invasion of metastatic HT-1080 cells into a reconstituted BM, such as a Matrigel/fibronectin (FN)-coated filter, in a concentration-dependent fashion. GG6-10 affected neither the tumor cell adhesion and haptotactic migration to ECM components (Matrigel and FN), nor the growth of HT-1080 cells. The gelatin zymography revealed that GG6-10 was able to inhibit not only the degradation of gelatin mediated by matrix metalloproteinases (MMP)-2 and -9 in conditioned medium of HT-1080 tumor cells but also the production of MMP from the tumor cells in a concentration-dependent manner. MMP production is well known to be positively regulated by various cytokines, such as tumor necrosis factor-alpha (TNF-alpha). Thus, we examined the effect of GG6-10 on the TNF-alpha-mediated translation of the MMP-9 gene using HT-1080 cells transfected with the MMP-9 promoter linked to the luciferase gene as a reporter. Similarly to prednisolone, GG6-10 was found to inhibit the TNF-alpha-inducible promoter activity. In keeping with these results, GG6-10 might inhibit tumor cell invasion by inhibiting the gelatinolysis mediated by MMP-2 and -9 and interfering with the production of MMP via inhibiting transcription of the promoter for MMP.

Cell Adhesion↗
PubMed1995

Photodynamic DNA-breaking activity of serum from patients with various photosensitivity dermatoses.

Various drugs and chemicals break the DNA strand under ultraviolet irradiation. This study aimed to clarify the DNA-breaking activity (DBA) of serum from 39 patients with various photosensitivity disorders and that from eight normal subjects. A mixture of serum and circular plasmid DNA was exposed to longwave ultraviolet radiation, and the photoinduced cleavage of plasmid DNA was examined by electrophoretic analysis. DBA was found in serum from patients with erythropoietic protoporphyria (2 of 2), drug-induced photosensitivity (3 of 5), chronic actinic dermatitis (1 of 12) and hydroa vacciniforme (1 of 1). DBA was not found in serum from patients with porphyria cutanea tarda, collagen diseases with photosensitivity, papulovesicular light eruption or pellagra. The inhibition profile of DBA by active oxygen scavengers was different between afloqualone- and tetracycline-induced photosensitivity and chronic actinic dermatitis. The present method was useful for the detection of serum phototoxicity and the investigation of the pathomechanisms of photosensitivity.

Adult↗
PubMed1995

Conservation of the hypersensitivity-pathogenicity regulatory gene hrpX of Xanthomonas campestris and X. oryzae.

The hrpX gene is essential for pathogenicity of Xanthomonas species. Loss of hrpX by mutation results in the loss of pathogenicity and a gain in the ability of Xanthomonas to cause the hypersensitive response in their respective host plants, suggesting that hrpX confers a means to evade this host defense response. The function of HrpX protein was predicted by sequencing of hrpXc and hrpXo from X. campestris pv. campestris and X. oryzae, respectively. The predicted amino acid sequences of the protein encoded by these respective genes revealed similarities (45.96%) to the HrpB protein of Burkholderia solanacearum, which has sequence identity to the transcriptional activator VirF of Yersinia enterocolitica and AraC of Escherichia coli. Thus, HrpX may regulate Xanthomonas virulence genes since a putative DNA binding domain present in the carboxyl terminal half of HrpX is highly conserved among HrpB, VirF and AraC and since over-expression of the carboxyl terminal half of HrpX in E. coli is lethal.

Amino Acid Sequence↗
PubMed1995

[Multiple dural arteriovenous shunts presenting as subarachnoid hemorrhage: a case report].

We present here an interesting case of multiple dural arteriovenous shunts (dAVS) in different locations at the same time. There have been very few reports on multiple dAVS. A 63-year-old man was admitted with a sudden onset of headache and vomiting. CT scan showed a typical subarachnoid hemorrhage (Fisher Group 3). Cerebral angiogram (6 vessel study) revealed two dural arteriovenous shunts at the same time. One was located on the anterior fossa fed by the anterior ethmoidal artery, and the other was located on the posterior fossa near the marginal sinus fed by the left ascending pharyngeal and occipital arteries. At first, transarterial embolization was performed for dAVS located on the posterior fossa. Radical operation was performed for both anterior and posterior fossa dAVS. Both dAVS had disappeared on postoperative angiograms.

Cerebral Angiography↗
PubMed1995

[A case of posterior fossa hypertrophic pachymeningitis with hydrocephalus].

A 52-year-old woman was admitted to our hospital because of nausea, headache, ataxic gait, and memory disturbance. CT scans and MRI showed a markedly enhanced lesion in the dura mater of the posterior fossa, edema in the right cerebellar hemisphere, occlusion of the transverse sinus, and hydrocephalus, suggesting hypertrophic pachymeningitis. Chronic otitis media and mastoiditis were also noted. Subjective complaints diminished after steroid administration. The patient underwent right suboccipital craniectomy and biopsy. The dura mater was markedly thickened, and the cerebellar surface was edematous. Histological examination revealed the thickened dura mater to be infiltrated by chronic inflammatory cells of forming lymphatic follicles and accompanied by Langhans giant cells. Inflammatory cells were not found in the cerebellar parenchyma, but were present in the subarachnoid space. Acid-fast stain, PAS and Grocott stain were negative. The cause of the hypertrophic pachymeningitis in this patient, may have been related to the chronic otitis media, but the patient's clinical course suggested that it might represent so-called "idiopathic hypertrophic pachymeningitis".

Cranial Fossa, Posterior↗
PubMed1995

Surgical treatment for ossification of the posterior longitudinal ligament of the cervical spine.

The results of surgical management of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine consisting of either anterior or posterior surgical decompression of the spinal cord and/or nerve roots were evaluated in 75 patients. The OPLL was continuous (COPLL) in 37 patients, segmental (SOPLL) in 29, mixed COPLL and SOPLL (MOPLL) in five, and circumscribed disk type (DOPLL) in four. Fourteen of the patients with COPLL, 27 with SOPLL, three with MOPLL, and all four with DOPLL were treated via the anterior approach with vertebrectomy and discectomy with anterior fusion. The remaining patients were treated by posterior laminoplasty or laminectomy. The overall mean improvement in the neurosurgical cervical spine scale (NCSS) score after surgery was 78.0% in those treated with anterior decompression and 46.1% in those treated with posterior decompression. The NCSS score in the latter group decreased during the follow-up period, from 10.4 to 9.7 points, whereas that in the anterior decompression group increased, from 12.9 to 13.0.

Adult↗
PubMed1995

[An acute epidural hematoma soon after nose blowing: a case report].

We reported a very rare case of an epidural hematoma soon after nose blowing. A 22-year-old male visited our hospital complaining of severe headache and nausea soon after he blew his nose. Thirteen years ago, he had a ventriculo-peritoneal (V-P) shunt operation for a pineal region tumor which had not recurred after irradiation. His left auditory tube had been patent. He hit his head about 3 months ago. On his arrival, his consciousness was almost clear but we observed slight right hemiparesis. Computed tomography of his head obtained on the first day showed the air in the hematoma in the left parietal epidural space which penetrated his petrosal bone from the mastoid air cells. Removal of his epidural hematoma was performed the next day and there was no abnormality of his parietal bone, dura and meningeal arteries. We supposed that nose blowing was what triggered his epidural hematoma. From pressure of nose blowing, the air of his nasopharyngeal space passed through his patent auditory tube into the tympanic cavity, and entered into the epidural space penetrating a microfracture or dissociation in the petrosal bone. In addition to this, V-P shunt system and the looser adhesion of dura to the skull in the young promoted entrance of air. Associated with formation of epidural hematoma in this case were four factors, "patency of auditory tube", "defect or microfracture of petrosal bone", "V-P shunt", "younger age" and triggered by nose blowing.

Acute Disease↗
PubMed1994

Induction in interferon-alpha/beta-treated hepatocytes of the inhibitor of the multiplication of IFN-alpha/beta-resistant Friend leukemia cells.

We reported previously that interferon-alpha/beta (IFN-alpha/beta)-treated hepatocytes in culture released a soluble factor(s) that suppressed the multiplication of an INF-alpha/beta-resistant clone of Friend leukemia cells (FLCs). To characterize the factor(s) further, we first examined the possibility that products of nonparenchymal cells (NPCs) included in small number in the hepatocyte cultures were involved in the inhibitory activity. We prepared cultures of purified adherent NPCs, mostly Kupffer cells, and sinusoidal endothelial cells, and culture supernatants of NPCs pretreated with IFN-alpha/beta were tested for the inhibitory activity for FLC multiplication. IFN did not induce any inhibitory activity in NPC cultures, whereas LPS-stimulated NPCs cultivated in parallel released several inhibitory factors including tumor necrosis factor-alpha (TNF-alpha). To explore the possibility that IFN augmented the release of hepatocyte cytosolic proteins, including arginase, we compared the inhibitory activity in culture supernatant of IFN-treated hepatocytes with that found in hepatocyte extract by anion-exchange chromatography. The IFN-induced inhibitory activity was eluted at relatively high salt concentration as a single peak, while the inhibitory activity in hepatocyte extract was co-eluted with arginase at low salt concentration. These results suggested that IFN induced production by hepatocytes of an inhibitor of FLC multiplication.

Animals↗
PubMed1994

DNA strand-breaking activities of quinolone antimicrobial agents under visible light irradiation.

The DNA strand-breaking activities of 9 quinolones, widely used as antimicrobial agents and suspected to induce photo-dermatological disorders in humans, were examined under irradiation using standard domestic fluorescent lamps. Two quinolones, tosufloxacin and enoxacin, converted the supercoiled covalently closed circular plasmid DNA to the open circular form under visible light irradiation. The maximum of photodynamic single strand-breaking activity for tosufloxacin was found to be 12% at 50 microM and that of enoxacin was 33% at a concentration of 2 mM. The DNA strand-breaking activities of photoirradiated tosufloxacin and enoxacin were markedly inhibited by NaN3 but only partially by D-mannitol, superoxide dismutase (SOD) and catalase did not inhibit these activities. These results suggest that some quinolone antimicrobial agents can be activated by visible light and induce phototoxic DNA damage in various organisms. We should carefully investigate such phototoxic activities during the development of new quinolones to avoid producing phototoxic disorders in man.

4-Quinolones↗
PubMed1994

Substrate specificity of Streptomyces beta-xylanase toward glucoxylan.

To discover the specificity of Streptomyces beta-xylanase toward xylan having glucose stubs, glucoxylan was prepared by the hydrogenation of cotton-seed cake glucuronoxylan. The glucoxylan was hydrolyzed by the beta-xylanase of Streptomyces olivaceoviridis E-86, and three kinds of glucoxylo-oligosaccharides were isolated from the hydrolysate by chromatographies on a charcoal column, preparative paper partition, and a Toyopearl HW-40F column. The isolated oligosaccharides had the structures of 2(3)-alpha-glucopyranosylxylotriose, 2(3)-alpha-(4-O-methyl-glucopyranosyl)xylotriose and 2(4)-alpha-glucopyranosylxylotetraose. From the structure of the above oligosaccharides and the results of our previous studies, we suggest that the specificity of Streptomyces beta-xylanase toward glucose stubs is the same as that toward glucuronic acid stubs, but differs considerably from that toward arabinose stubs.

Carbohydrate Conformation↗