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Biomedical subjects

H Seki

Publications and source records attributed to H Seki.

407 records · Page 23Linked to original sources
PubMedDate not supplied

Effect of mannitol on rCBF in canine thalamic ischemia--an experimental study.

Using the canine thalamic infarction model, we have investigated the effects of 10 ml/kg of 20% mannitol on the hemodynamics of the ischemic brain. Mannitol was found to cause an increase in rCBF, but it is not marked in animals with severe ischemic foci. Increases were statistically significant in the animals with moderate ischemia. Increases in rCBF due to mannitol administration lasted for about 1 hour, as did the rise in serum osmolarity. The actual relationship between these two parameters, remains unclear.

Animals↗
PubMedDate not supplied

The CO2 response in focal cerebral ischemia--sequential changes following recirculation.

The study was undertaken to determine the effects of various levels of ischemia on the CO2 response and on the development of infarction using the canine thalamic infarction model. Three groups were studied: those with severe ischemia (rCBF below 40% of the pre-occlusion levels), moderate ischemia (between 40% and 70%) and mild ischemia (greater than 70%). The CO2 response was measured after 30 minutes, 1, 2 and 6 hours of occlusion and then for 4 hours after recirculation. The CO2 response recovered after 30 minutes of occlusion in the severely ischemic animals, but in 8 of the 9 animals with 1 or more hours of occlusion, an impaired CO2 reactivity was found during occlusion and during recirculation. Among moderately ischemic animals, many showed impaired CO2 reactivity during occlusion, but following recirculation no single trend was observed. Among mildly ischemic animals, almost no abnormalities in the CO2 response were seen either during 6 hours of occlusion or thereafter. Among the 11 animals from all 3 groups which showed impaired CO2 reactivity, 10 developed infarction, while among the 10 animals which showed no impaired CO2 reactivity, in 9 infarction did not arise.

Animals↗
PubMedDate not supplied

Hemodynamics in hemorrhagic infarction--an experimental study.

Using the canine thalamic infarction model, hemodynamics, CO2 responses and thalamic EEG changes were studied in 7 dogs. Of the 7 animals, 4 showed hemorrhagic infarction and 3 did not, following recirculation after 6 hours of vascular occlusion. 1) The rCBF threshold for producing hemorrhagic infarction when recirculation following 6 hours of vascular occlusion was approximately 50% of the pre-occlusion level. 2) rCBF of the animals showing hemorrhagic infarction included hyperperfusion due to recirculation, and then fell to a level below the pre-occlusion level in a relatively short period. The CO2 response became disturbed both during occlusion and after release of occlusion. Thalamic EEG was nearly flat during vascular occlusion and recovery was not seen following recirculation. 3) rCBF of the animals not showing hemorrhagic infarction recovered rapidly to the pre-occlusion level due to recirculation. The CO2 response was somewhat disturbed during occlusion, but recovered following recirculation. Thalamic EEG was well preserved both during occlusion and after release.

Animals↗
PubMedDate not supplied

On the free radical-induced aggregation of ribonuclease - a pulse radiolysis study using the light scattering detection method.

The aggregation of bovine ribonuclease (RNase) induced by either .OH or Br(2) radicals has been studied. These radicals, which were generated by pulse radiolysis of aqueous solution with 16 MeV electrons, readily attack the enzyme thus producing RNase-radicals which subsequently combine. At initial radical concentrations low enough (less than 0.1 radical per enzyme molecule) to prevent multimerizations other than dimerization, rate constants for the latter process were determined from the increase of the light scattering intensity after the pulse: 2k2 = (22 +/- 0.3) 106 l/mol s (Br(2) initiated dimerization) and (5.4 +/- 0.4) 106 l/mol s (.OH initiated dimerization). The G-values for dimerization are: 1.3 (Br(2) and 0.85 (.OH). Transient optical absorption measurements revealed the existence of phenoxyl radicals of tyrosine (TyrO.) that decayed with a rate constant of 2 K2 (total) = (5.5 +/- 0.7) 106 l/mol s (Br(2)-case). The difference between k2 and k2 (total) presumably indicates the occurrence of disproportionation.

Animals↗
PubMedDate not supplied

A case of bilateral cerebellar peduncle infarction.

A 68-year-old woman had an abrupt onset of severe headache, nausea, vertigo, difficulty in standing and dysarthria. A CT scan of the brain disclosed bilateral symmetrical round infarctions involving the middle cerebellar peduncles. She exhibited marked limb ataxia, gait ataxia, dysarthria and transient gaze nystagmus. Occlusion of the right vertebral artery associated with a stenosis of the basilar artery just proximal to the origin of the anterior inferior cerebellar arteries shown in angiograms were thought to be the cause.

Aged↗
PubMedDate not supplied

Gastric toxicity related to perfusion of the stomach via the left inferior phrenic artery during hepatic arterial infusion chemotherapy: report of two cases.

We present two cases of gastric toxicity related to hepatic arterial infusion chemotherapy (HAIC) for liver metastases. The gastric toxicity was caused by the inflow of infused drugs into the stomach via the left inferior phrenic artery arising from the celiac arterial trunk. The catheter hole was placed in the celiac arterial trunk with occlusion of the splenic and many gastric arteries. It must be kept in mind that perfusion of the stomach may occur through the left inferior phrenic artery in HAIC.

Angiography, Digital Subtraction↗
PubMedDate not supplied

The micronucleus test with mouse peripheral blood on N-methyl-N'-nitro-N-nitrosoguanidine and mitomycin C.

The micronucleus test using mouse peripheral blood was conducted with N-methyl-N'-nitro-N-nitro-soguanidine (MNNG) and mitomycin C (MMC) as part of the 5th collaborative study supported by the Environmental Mutagen Society of Japan (CSGMT/MMS.JEMS). Male CD-1 mice were intraperitoneally injected once with 12.5-100 mg/kg of MMC. Peripheral blood was drawn at different intervals after treatment, placed on slides previously coated with acridine orange and the numbers of reticulocytes with micronuclei (MNRETs) were scored. The experiments indicated that the maximum effect of both MNNG and MMC was found about 48 h after treatment, and that the micronucleus test using peripheral blood is useful for the screening of chemicals throughout the experimental period in a single animal.

Animals↗
PubMedDate not supplied

Disulfide-linked and non-disulfide-linked gamma/delta T-cell antigen receptors: differential expression on T-cell lines and clones derived from normal donors and patients with primary immunodeficiency disorders.

We studied the expression of gamma delta T cell receptors (TCR) on T-cell lines and clones derived from peripheral blood lymphocytes (PBL) from certain patients with primary immunodeficiency disorders and normal donors. Immunoprecipitation with the anti-Leu 4, anti-gamma-chain and/or anti-delta-chain monoclonal antibodies followed by SDS-PAGE analysis revealed that 7 of 13 (54%) T-cell lines and clones developed from PBL of patients with primary immunodeficiency disorders expressed non-disulfide-linked gamma delta TCR, utilizing either the C gamma 2abc or the C gamma 2bc gamma-chain constant region gene segment. 5 of 13 (38%) T-cell lines/clones expressed disulfide-linked gamma delta TCR, whereas an additional T-cell line was comprised of T cells expressing either disulfide-linked (C gamma 1) or non-disulfide-linked (C gamma 2bc) gamma delta TCR. T-cell lines and clones developed from four of light patients with primary immunodeficiency disorders exhibited exclusively non-disulfide-linked gamma delta TCR utilizing either the C gamma 2abc or the C gamma 2bc gamma-chain segment. T-cell lines derived from a fifth patient exhibited primarily non-disulfide-linked gamma delta TCR, bringing to five of eight the numbers of patients that expressed exclusively or primarily non-disulfide-linked gamma delta TCR. T-cell lines/clones derived from the remaining three patients exhibited exclusively disulfide-linked gamma delta TCR. The age of these patients varied over a wide range and there was not an association between their age and the type of gamma delta TCR expressed on T-cell lines derived from their PBL. In contrast, to these findings 14 of 16 (87.5%) T-cell clones derived from PBL of normal donors expressed disulfide-linked gamma delta TCR, whereas only 2 of 16 (12.5% expressed non-disulfide linked gamma delta TCR. Among the T-cell clones from normal donors which express disulfide-linked gamma delta TCR two different types were identified. Those exhibiting under reducing conditions on SDS-PAGE two completely resolved polypeptide chains in the range of 37 kD to 44 kD, and those exhibiting under the same conditions indistinguishable overlapping gamma- and delta- chains in the range of 40-42 kD. Several T-cell lines and clones from normal donors or patients with primary immunodeficiency that expressed either disulfide- or non-disulfide-linked gamma delta TCR were delta TCS1+, demonstrating that the delta TCS1 determinant is expressed on both types of gamma delta TCR.(ABSTRACT TRUNCATED AT 400 WORDS)

Antigens, CD↗
PubMedDate not supplied

Primary retroperitoneal mucinous cystadenocarcinoma: report of a case.

A case of primary retroperitoneal mucinous cystadenocarcinoma is presented. Ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) examinations demonstrated a large cystic tumor with solid excrescences. Angiographic examination demonstrated an avascular area with small areas of faint blush. It must be borne in mind that mucinous cystadenocarcinoma originating from the retroperitoneum can occur, although it is very rare.

Cystadenocarcinoma↗
PubMedDate not supplied

Assessment of proliferating cell nuclear antigen (PCNA) immunoreactivity in exocrine pancreatic carcinomas.

Twenty patients with exocrine pancreatic carcinomas were studied immunohistochemically, using a monoclonal antibody against PCNA. The percentage of tumor cells with positive staining was defined as PCNA Labelling Index (L.I.), and ranged from 13.8% to 92.8%. PCNA LI was found to correlate significantly with grading and more specifically with mitotic activity and degree of nuclear anaplasia. No correlation was found with glandular differentiation or with vessel invasion, lymphatic vessel invasion, lymph node metastasis, perineural invasion or size of tumor. Our results indicate that mitotic activity and degree of nuclear anaplasia might be the most important parameters to take into consideration, when studying the role of PCNA in exocrine pancreatic carcinomas.

Adult↗