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Biomedical subjects

M Kojima

Publications and source records attributed to M Kojima.

At least 757 records · Page 42Linked to original sources
PubMed1986

Early changes of experimentally induced cerebral aneurysms in rats. Light-microscopic study.

The changes of the anterior cerebral artery/olfactory artery junction, one of the favorite sites of aneurysm formation, in rats treated with unilateral ligation of the common carotid artery and renal hypertension were investigated by light microscopy. The initial changes of aneurysm occurred not at the apex itself, but on the distal side of the major branch adjacent to the apex, at the intimal pad and the neighboring distal portion. Here the internal elastic lamina showed various degenerative changes and disappearance. The neighboring distal portion adjacent to the intimal pad showed a shallow depression associated with a thinning of the media due to a decrease of medial smooth muscle cells in number even in some control animals. Such degenerative changes of the internal elastic lamina and medial smooth muscle cells caused by hemodynamic stress due to branching structure, including intimal pads, augmented by the experimental treatment, are supposed to be the basis for aneurysm formation.

Animals↗
PubMed1986

[The effect of hyperglycemia on ischemic brain damage: relevance to the local cerebral blood flow].

The effect of hyperglycemia on ischemic brain damage in rats was studied by measuring the local cerebral blood flow (LCBF) using a transient middle artery (MCA) occlusion model. Rats, fasted except for water for 12-16 hours, were used. They were anesthetized with halothane and the stem of the left MCA was occluded for 2 hours by a microclip. Reperfusion was performed by removal of the clip. The rats were awaken from anesthesia after removal of the clip. Hyperglycemia was induced by intraperitoneal injection of 50% glucose and same volume of 50% D-mannitol or physiological saline were injected intraperitoneally 20 minutes before MCA occlusion in control rats. LCBF was measured by quantitative autoradiography using 14C-iodoantipyrine 2 hours after clipping and 2 hours after reperfusion. Some rats were prepared for neuropathological observation 72 hours after reperfusion. In hyperglycemic rats, plasma glucose concentration rose to over 500 mg/dl at the peak. A hyperglycemic state around 300 mg/dl was maintained during the experiments. Elevation of hematocrit and plasma osmolarity to the same degree were observed in both hyperglycemic and mannitol pretreated rats. On histological study ischemic neuronal cell damage was found to be more extensive in hyperglycemic rats than in the saline pretreated rats. At 2 hours after MCA occlusion, LCBF in the ischemic focus decreased significantly in hyperglycemic rats compared with the control. The reduction of LCBF was observed also in the contralateral non-ischemic side (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

3-Methoxy-4-aminoazobenzene, a selective inducer for a high spin form of cytochrome P-448 in rat liver microsomes.

Treatment of Sprague Dawley rats with 3-methoxy-4-aminoazobenzene (3-MeO-AAB) resulted in striking increase of the activity of hepatic microsomal cytochrome P-450s which could efficiently catalyze the mutagenic activation of hepatocarcinogenic aromatic amines such as a tryptophan-pyrolysate component, Trp P-2, and a glutamic acid-pyrolysate component, Glu P-1. The 3-MeO-AAB-induced cytochrome P-450 (3-MeO-AAB-P-450) was examined for the molecular character by immuno-Western blotting using monoclonal antibody to 3-methylcholanthrene-induced cytochrome P-448 (P-448H; m.w. 54,000).

Animals↗
PubMed1985

Immunoelectron microscopic study of Hodgkin's disease.

Seven patients with Hodgkin's disease were studied for the presence of lysozyme and alpha-1-antitrypsin activity by immunoelectron microscopy. As a result, Reed-Sternberg cells, Hodgkin's cells, and atypical cells were distinctly positive for lysozyme in four cases and weakly positive in the remaining three cases. These cells were also positive for alpha-1-antitrypsin in all cases. Because the cells of the monocyte-macrophage lineage also bore lysozyme and alpha-1-antitrypsin, it is suggested that Reed-Sternberg cells, Hodgkin's cells, and the atypical cells are derived from the monocyte-macrophage lineage.

Histocytochemistry↗
PubMed1985

A putative prohormone processing protease in bovine adrenal medulla specifically cleaving in between Lys-Arg sequences.

Paired basic residues, particularly Lys-Arg, are known as a typical site for proteolytic processing of prohormones. In this study, we confirmed the presence of a novel protease exhibiting substrate specificity toward Lys-Arg sequence. It was partially purified from the soluble fraction of bovine adrenomedullary chromaffin granules by using an affinity chromatography on soybean trypsin inhibitor-Sepharose. The enzyme, with optimal pH around 7.5-9.5, is classified into a serine-protease family by its inhibition spectrum. The enzyme specifically cleaves in between the Lys-Arg bonds of the peptides related to proenkephalins, but the sequences of Arg-Arg, Arg-Lys and a single basic residue (Arg or Lys) in the substrates are not affected by the enzyme. The unique substrate specificity of the enzyme suggests that it is distinct from pancreatic trypsin and may be physiologically involved in proenkephalin processing.

Adrenal Medulla↗
PubMed1985

Characteristic distribution of noradrenergic terminals on the anterior horn motoneurons innervating the perineal striated muscles in the rat. An immuno-electromicroscopic study.

Dopamine-beta-hydroxylase (DBH) immunohistochemistry was used to demonstrate the noradrenergic fibers and terminals in the anterior column of the rat lumbosacral spinal segments. PAP-positive varicose fibers were widely distributed in the gray matter with preferential accumulation in the nuclear regions containing motoneurons involved in the contraction of perineal striated muscles. Unmyelinated DBH fibers were composed of nodular enlargements (varicosities, 0.4-3.0 microns in diameter) and very fine, short intervals (intervaricose segments, 0.1-0.2 micron in diameter and 1.0-4.0 microns in length). DBH-positive dense products were electron microscopically often confined within small granular particles and less frequently within large granules. Additionally, in order to characterize the innervation pattern of noradrenergic fibers on dendritic bundles organized in the motoneuronal pools innervating the pelvic small muscles, semi-quantitative analysis was done in the area of the dorsolateral nucleus endowed with especially well-developed dendritic bundles. DBH terminals contacting with unreactive dendrites were more common (67.9%) than those with neuronal somata (15.1%), and the remainder (17%) had no contacts with surrounding neuronal elements. Furthermore, specialized synaptic formations were observed in only 20.1% of these nodules. The results suggest that bulbospinal descending noradrenergic neuron systems influence the functioning of pelvic muscles principally via the neuronal contacts with dendritic bundles in the spinal cord.

Animals↗
PubMed1985

Enhancement by estrogen treatment of -bungarotoxin binding in fetal mouse amygdala cells reaggregated in vitro.

Dissociated amygdala cells from 17-day-old mouse fetuses were cultivated in a flask for 7 days to form aggregates. In the aggregates there developed typical synaptic structures and [125I]alpha-bungarotoxin binding capacity. An addition of estradiol (100 ng/ml) in the culture medium caused a significant increase in the toxin binding capacity. From these results it is concluded that estradiol enhances alpha-bungarotoxin binding capacity in the amygdala by exerting direct effects on the developing amygdala cells.

Amygdala↗
PubMed1985

Rudimentary polydactyly: report of five cases.

Rudimentary polydactyly was found in five patients. Surgical exploration of the papules revealed findings that have not been previously published. A cord-like structure arises from the bottom of the papule, with its proximal portion joining the neurovascular bundle of the digit. Histologic examination of the cord showed strong similarity to the neurovascular bundle of a finger. From these findings, we assume that rudimentary polydactyly may represent the amputation stump of pedunculated fingers.

Child↗
PubMed1985

A case report of malignant lymphoma with Hashimoto's thyroiditis.

The authors studied a case of malignant lymphoma arising in a patient with Hashimoto's thyroiditis. Histologically, a malignant, large cell, immunoblastic lymphoma was revealed, with the surrounding area showing changes typical of Hashimoto's thyroiditis. Immunoperoxidase staining proved the lymphoma cells to have intracytoplasmic immunoglobulins (IgA, k). Infiltrating interfollicular plasma cells containing the same kind of intracytoplasmic immunoglobulins (IgA, k) were present in the surrounding Hashimoto's thyroiditis lesions. Thus, it is possible that the interfollicular infiltrating plasma cells evolved into a malignant lymphoma in this case of Hashimoto's thyroiditis.

Aged↗
PubMed1985

Immunohistochemical studies of the serotonergic supraependymal plexus in the mammalian ventricular system, with special reference to the characteristic reticular ramification.

Distributional and morphological features, especially characteristics of the ramification of serotonin-containing supraependymal fibers (SEF), were studied in the ventricular systems of mammals (mouse, rat, guinea pig, rabbit, cat, dog, monkey) by means of a modified peroxidase antiperoxidase technique, using antiserotonin antiserum prepared in our laboratory. SEF were present in all ventricular systems, except on the third ventricle floor and in the choroid plexus. The density of SEF was higher in the smaller species. In the rat, light- and scanning electron microscopical SEF were almost completely abolished 1 week after intraventricular administration of 5,6-dihydroxytryptamine. Ramification of SEF was complicated; the SEF formed a true network with frequent anastomosing. In the ventricular system of rats rendered hydrocephalic by kaolin administration, the mode of axonal branching in the supraependymal plexus could best be analyzed by the scanning electron microscope because the meshes of the plexus were spread out.

Animals↗
PubMed1985

Rapid purification of nucleosome assembly protein (AP-I) and production of monoclonal antibodies against it.

A nucleosome assembly protein (AP-I) was purified approximately 50% from the cytosol of HeLa S3 cells by three purification steps. Using this protein fraction as an antigen, we established three stable hybridomas that secrete monoclonal antibodies specific for AP-I by the conventional method of cell fusion. Immunoblotting of the HeLa S3 cytosol, proved AP-I exists as a 58-kDa peptide in vivo, not as the 53-kDa peptide previously identified as active in nucleosome assembly (Ishimi, Y., et al., Eur. J. Biochem., 142, 431-439, 1984). An immunocytochemical study using the monoclonal antibody with the highest specificity against AP-I pin pointed the intranuclear localization of AP-I in HeLa S3 cells.

Animals↗