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Biomedical subjects

M Izawa

Publications and source records attributed to M Izawa.

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

Molecular analysis of the gene cluster involved in cephalosporin biosynthesis from Lysobacter lactamgenus YK90.

Determination of the nucleotide sequence downstream from the Lysobacter lactamgenus pcbC gene encoding isopenicillin N synthase revealed that five open-reading frames (ORF) including the pcbC gene were tightly linked in the same orientation. Each ORF has the remarkable feature of the protein-coding frame in the DNA sequence with a high G+C content. Expression in Escherichia coli and a comparison of the deduced amino acid sequences with published sequences showed that the gene cluster contained a deacetoxycephalosporin C synthetase (DAOCS) gene (cefE), an ORF having homology with the Cephalosporium acremonium DAOCS/deacetylcephalosporin C synthetase gene (cefEF), an isopenicillin N epimerase gene(cefD), and a beta-lactamase gene. The gene order was pcbC-cefE-ORF3-cefD-beta-lactamase.

Amino Acid Sequence↗
PubMed1996

UV-induced apoptosis in rat skin.

Sunburn cells appear in the epidermis after UVB irradiation and are histologically suggested to be keratinocytes undergoing apoptosis. We here show a known biochemical process of apoptosis, genomic DNA fragmentation, in rat skin. UVB irradiation induced sunburn cells in the epidermis of rat skin at a lower dosage and the cleavage of genome DNA to nucleosomal size units at dosages of more than 0.3 J/cm2. The fragmented DNA observed could be driven from the epidermis though the involvement of DNA in dermal cells cannot be neglected. PUVA treatment also induced sunburn cells and the fragmentation of genome DNA. The extent of DNA fragmentation by UVB irradiation was enhanced depending on the dosage and peaked at 12-24 h after the irradiation. The induction of the DNA fragmentation observed in this study indicates the presence of a common pathway related to the DNA damage-induced apoptosis in the skin, and might become a useful marker in the course of in vivo studies on the physiological role of apoptotic process in the skin.

Animals↗
PubMed1996

Gamma Knife radiosurgery for meningiomas: four cases of radiation-induced edema.

We review 48 cases of meningioma treated with Gamma Knife radiosurgery. The mean marginal dose was 15 Gy and the mean follow-up was 12 months. Follow-up computed tomography and magnetic resonance imaging showed tumor shrinkage in 19 cases, central necrosis in 1 case, loss of contrast enhancement in 1 case, and no change in 27 cases. We noted 4 cases of radiation-induced edema in supratentorial meningiomas.

Adult↗
PubMed1996

Adult moyamoya disease progressing from unilateral to bilateral involvement .

A 30-year-old female and a 38-year-old male developed "definite" moyamoya disease after presenting with "probable" moyamoya disease manifesting as ischemic stroke. Angiography at first presentation demonstrated unilateral involvement with normal contralateral findings. The cases were classified as adult type "probable" moyamoya disease according to the diagnostic criteria. Follow-up angiography demonstrated the occlusive lesions had become bilateral, satisfying the criteria for "definite" cases. Serial angiography is required in adults presenting with "probable" moyamoya disease manifesting as ischemic stroke.

Adult↗
PubMed1996

Correlation between MR image characteristics and histological features of acoustic schwannoma.

We retrospectively studied 21 cases of histologically proven acoustic shwannomas with an emphasis on the correlation of their magnetic resonance imaging (MRI) findings and histological features. All cases were of low signal intensity in the T1W MRI. In the T2W MRI, 9 of them were of homogeneous high signal intensity (Hom-HSI-T2) and 12 of them were of heterogeneous high signal intensity (Het-HSI-T2). The cases of Hom-HSI-T2 were generally associated with capsular enhancement, and were usually cystic tumors with high vascularities and mainly Antoni A tissues. On the contrary, the cases of Het-HSI-T2 were generally associated with homogeneous enhancement, and were usually solid tumors with low vascularities and various tissue components.

Adult↗
PubMed1995

Management of intracranial hemorrhage associated with anticoagulant therapy.

BACKGROUND: Intracranial hemorrhage may be a particularly devastating complication of anticoagulant therapy. Very few accounts have reported data on the duration of anticoagulant discontinuation following intracranial hemorrhage or the intensity of anticoagulation during treatment for it, although we must adequately manage such a complication. METHODS: We analyzed the management of warfarin-related intracranial hemorrhages in 27 patients with cardiac diseases. We evaluated the degree of anticoagulation using the thrombotest. Anticoagulants were stopped as soon as the diagnosis of intracranial hemorrhage was established by computed tomographic scan. RESULTS: Mechanical valve prosthesis patients, who required intensive long-term anticoagulant therapy, constituted the majority of our series (74.1%). Intraoperative hemostasis was brought under control despite low thrombotest values (13%-68%) at the time of surgery except for the acute subdural hematoma (SDH) patients with cerebral contusion. Early resumption of anticoagulant therapy (within 3 days) did not cause intracranial rebleeding in any operative patient. All the chronic SDH patients and some of the subcortical hematoma patients had a good outcome. All three patients with acute SDH and contusion, however, had a fatal outcome because of intracranial rebleeding within a short period of time or ineffective intraoperative hemostasis. CONCLUSIONS: The patients with anticoagulant-related intracranial hemorrhage may undergo surgery with thrombotest values approximately between 20% and 60%, and anticoagulants can be resumed after an interval of 3 days. Aggressive surgery should particularly be performed in patients with anticoagulation-related chronic SDH or subcortical hemorrhage, as in the cases of anticoagulant-unrelated intracranial hemorrhage.

Adolescent↗
PubMed1995

A 3-deazauracil-resistant mutant of Bacillus subtilis with increased production of cytidine.

Bacillus subtilis No. 344 is a cytidine-producing mutant strain derived from wild type strain No. 122. When 3-deazauracil-resistant mutants were derived from strain No. 344, some of the mutants had higher productivities of cytidine. Among them, strain No. 428 accumulated 14.2 mg/ml cytidine in the culture. Cytidine 5'-triphosphate (CTP) synthetase from strain No. 428 changed to be free from feedback inhibition by CTP, compared with the enzyme from strain No. 344.

Bacillus subtilis↗
PubMed1994

HLA-type of cerebral vasospasm patients after aneurysmal subarachnoid hemorrhage.

We studied human lymphocyte antigen (HLA) types in a group of 45 patients who had aneurysmal subarachnoid hemorrhage (SAH). A significantly increased frequency of HLA antigen A31 and a significantly decreased frequency of HLA antigen B40 were found. In patients with delayed ischemic neurological deficit (DIND) following aneurysmal SAH and HLA typing, HLA-Bw60 antigen showed significant increases; in patients who did not develop HLA-Aw33 and -Cw4 antigens showed significant. Among the patients with Fisher's Group 3 on CT, in particular, these antigens significantly increased when compared with controls from the same geographic area. These results suggest that HLA-Bw60 antigen plays a role as predisposing factor of DIND resulting from vasospasm following aneurysmal SAH, and that HLA-Aw33 and -Cw4 exert protective influence against DIND.

Adult↗
PubMed1994

Acetylcholine determination of cerebrospinal fluid in aneurysmal subarachnoid hemorrhage.

Acetylcholine (ACh) concentrations were determined serially in cerebrospinal fluid (CSF) obtained from 23 patients with aneurysmal subarachnoid hemorrhage (SAH) by high-performance liquid chromatography (HPLC) with electrochemical detection (ED). The values of CSF ACh were significantly low in the initial stage of SAH, and increased subsequently but they did not return to control values within 3 weeks. In addition, serial measurements of CSF butyrylcholinesterase (BChE) activity in 12 SAH patients showed that the activity was elevated significantly in the initial stage of SAH and returned to control levels within a week. This discrepancy in the recovery period between the ACh levels and the BChE activity in CSF indicated that significantly lower CSF ACh levels after SAH could not be attributed to plasma BChE contamination of CSF. These results suggested central cholinergic dysfunction after SAH, especially in the initial stage.

Acetylcholine↗
PubMed1994

Helminth survey of wildcats in Japan.

Two Iriomote cats (Felis iriomotensis) and 2 Tsushima leopard cats (Felis bengalensis euptilura) killed probably by traffic accidents were submitted to the helminthological examination. In Iriomote cats, 8 species of parasites (Spirometra erinacei, Toxocara cati, Molineus springsmithi, Uncinaria maya, Capillaria aerophila, C. felis-cati, larvae of an unidentifiable lung worm and one species of Acanthocephala) were found. In Tsushima leopard cats, 10 species of parasites (Pharyngostomum cordatum, Spirometra erinacei, Toxocara cati, Molineus springsmithi, Arthrostoma hunanensis, Uncinaria felidis, Capillaria felis-cati, larvae of an unidentifiable lung worm, and two species of Acanthocephala) were detected.

Animals↗
PubMed1994

Magnetic resonance imaging and quantitative analysis of contents of epidermoid and dermoid cysts.

The intracapsular cholesterol, protein, and calcium contents of epidermoid and dermoid cysts from seven patients were compared with the signal intensities on T1-weighted spin-echo magnetic resonance (MR) images. All specimens had a paste-like consistency when resected. Epidermoid and dermoid cysts demonstrated a wide range of cholesterol and calcium contents, and epidermoid cysts were not always rich in cholesterol. Five patients had cysts with lower signal intensity than white matter, which contained more than 18.3 mg/g wet weight of protein. One of these patients had the highest cholesterol content of all seven patients (22.25 mg/g wet weight) and another had the highest calcium content (0.75 mg/g wet weight). Two patients had cysts with higher signal intensity than white matter, with protein contents of lower than 4.3 mg/g wet weight. High protein content (> 18.3 mg/g wet weight) may decrease signal intensity on T1-weighted MR images, while low protein content (< 4.3 mg/g wet weight) may increase signal intensity in epidermoid and dermoid cysts with high viscosity (paste-like consistency) contents.

Adolescent↗
PubMed1993

Immunohistochemical detection of carbohydrate determinant 19-9 (CA 19-9) in intracranial epidermoid and dermoid cysts.

We evaluated carbohydrate antigen (CA) 19-9 levels of intracranial dermoid and epidermoid cyst in serum and intratumoral tissue. The preoperative serum levels were mildly to moderately higher than their normal ranges in four of seven patients. In four patients with high serum CA 19-9 levels, they returned to normal ranges in three who had the cyst resected totally and remained slightly high in one with residual cyst. Immunohistochemical studies using anti-CA 19-9 antibody demonstrated positively stained capsule and keratinous tissue. Serum CA 19-9 levels of intracranial dermoid or epidermoid cysts with more teratomatous components may be elevated above normal levels.

Adolescent↗
PubMed1993

Individual diversity of IL-6 generation by human monocytes with lentinan administration.

Effect of in vivo administration of lentinan on IL-6 generation by human peripheral blood monocytes was examined using 5 healthy volunteers. Monocytes isolated from them before and 3 days after intravenous administration of 2 mg lentinan per person were cultured for 2 days and then the levels of IL-6 in the supernatants of cultured monocytes were determined. In vivo lentinan administration elicited an increase in IL-6 generation by monocytes in 3 of 5 cases. Failure to increase IL-6 generation by monocytes in two cases is characteristic of lentinan, since these monocytes generated an apparent level of IL-6 in response to lipopolysaccharide, a potent monocyte activator. Thus, it was demonstrated that lentinan was capable of augmenting IL-6 generation by human monocytes and that there was individual difference in their responsiveness to lentinan.

Acute-Phase Proteins↗
PubMed1993

Management of adult moyamoya disease.

The surgical management of adult moyamoya disease was evaluated retrospectively. Eight of 10 patients with hemorrhagic stroke had no bleeding episodes and eight of 11 patients with ischemic stroke were asymptomatic postoperatively. Angiography demonstrated neovascularization via the external carotid artery (ECA) in 22 sites (88%) and reduced basal moyamoya vessels in 11 sites (44%) postoperatively. These symptomatic improvements and angiographic findings suggest that reconstructive surgery for adult moyamoya disease patients with hemorrhagic or ischemic stroke is effective in decreasing hemodynamic stress in the basal moyamoya vessels and increasing the cortical blood supply via the ECA.

Adult↗