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Biomedical subjects

M Kojimahara

Publications and source records attributed to M Kojimahara.

At least 19 recordsLinked to original sources
PubMed1994

Detection of hydroquinone in a poisoning case.

A fatality due to the ingestion of photographic developer solution containing hydroquinone is described. Hydroquinone was extracted from autopsy materials and identified using gas chromatography-mass spectrometry (GC-MS). The concentration of hydroquinone in the urine, liver, and kidney were 3.4 micrograms/mL, 0.5 and 0.2 microgram/g, respectively.

Catechols↗
PubMed1993

[An autopsy case of traumatic middle cerebral artery occlusion].

An autopsy case of middle cerebral artery occlusion following closed head injury is reported. A 16-year-old laborer received head injuries in a motorcycle-automobile accident. On first examination at the time of admission, semi-coma, left-sided hemiplegia and other focal cerebral signs were evident. Roentgenographic examination revealed fractures of the skull. A CT scan of the head 24 h after injury revealed a massive right-sided cerebral infarct with midline shift. On the 4th day, angiography showed tapering occlusion of the right internal carotid artery at the top of the 3rd cervical vertebra. The patient died from the cerebral infarct 7 days after injury. At autopsy, thrombotic obstruction at the origin of the right middle cerebral artery due to a dissecting aneurysm was found.

Accidents, Traffic↗
PubMed1990

Endothelial cilia in rat mesenteric arteries and intramyocardial capillaries.

We report for the first time the presence of endothelial cilia in rat blood vessels. They are seen in the mesenteric arteries of hypertensive rats and the intramyocardial capillaries of aged rats. The cilia are solitary and have the shape of the "9 + 0" axonemal structure. The processes of the basal foot and the transitional fiber are accompanied by basal bodies. The function of the solitary cilia is obscure.

Animals↗
PubMed1988

Intimal laminated elastosis in the intrarenal arteries. An electron microscopic study.

Using kidneys from diabetic patients, the morphogenesis of elastic hyperplasia ("laminated elastosis") in the intrarenal arteries was studied by electron microscopy. In the thickened intima, myointimal cells produced ground substance, collagen fibers and elastic tissue. The elastic tissue was stained black electron microscopically with orcein. Newly-formed elastic tissue in the intima was first found on either the basement membrane or basement membrane-like materials around the myointimal cells and endothelial cells. Subsequently, small areas of elastic tissue aggregated and fused to form larger areas of elastic tissue or concentric thick elastic laminae, the latter containing a large number of collagen fibrils. Upon treatment with elastase, newly-formed elastic tissue was digested, but the microfibrillar component remained unstained.

Adult↗
PubMed1987

Ultrastructural study of hemangiomas. 5. Glomus tumor (Masson).

The fine structure of four cases of glomus tumor was described. All of the cases showed a solid type, and the glomus cells were shown to be typical or modified smooth muscle cells. Our conclusion is that the glomus cells are not derived from pericytes, but from smooth muscle cells of vascular part of the glomus, and are thought to be a specialized smooth muscle cell tumor.

Adult↗
PubMed1986

Ultrastructural study of hemangiomas. 4. Cavernous hemangioma of the liver.

Seven cases of cavernous hemangioma of the liver found accidentally at autopsy were studied by electron microscope. The structures of the hemangioma consisted of capillaries and the intervening stromal cells. The endothelial cells contained pinocytotic vesicles, scattered ribosomes, rough endoplasmic reticulum, and Golgi apparatus. A distinct basement membrane was present beneath the endothelial cells, and multilaminated arrangement of the basement membrane was sometimes observed beneath the endothelial cells. The endothelial cells also contained numerous cytoplasmic filaments, but contained sparse specific endothelial granules. The internal elastic lamina was hardly seen at all in the hemangioma. The stromal cells showed typical smooth muscle cells, modified smooth muscle cells, and fibroblast-like cells. Elastic tissue as well as collagen fibers was present within the intervening stroma. Neither adventitia nor nerve fibers were found in the cavernous hemangioma. It is thought that cavernous hemangioma of the liver may be of a hamartomatous nature.

Aged↗
PubMed1986

Ultrastructural study of hemangiomas. 3. Specific endothelial granules in the cerebellar hemangioblastoma.

We report a case of cerebellar hemangioblastoma in a 45-year-old man. To our knowledge, only two papers have been reported previously on the cystic inclusions other than Weibel-Palade bodies in the endothelial cells, and this is the first reported case of a hemangioblastoma exhibiting large, cystic endothelial inclusions with microtubular subunits. The function of these inclusions is obscure.

Capillaries↗
PubMed1986

Endothelial cells in the rectal venous plexus. An electron microscopic study.

The endothelial cells of the rectal venous plexus were studied by electron microscope. The endothelial cytoplasm contained numerous specific granules, intracytoplasmic filaments, and 'anchoring filaments'. The present observations suggest that specific endothelial granules are formed in the Golgi apparatus. Thin 50-70 A and thick filaments 100-120 A were found in the endothelial cytoplasm. Also anchoring filaments between the plasma membrane of the endothelial cells and the underlying basement membrane (or subendothelial microfibrils) were present. The cytoplasmic filaments as well as the anchoring filaments are thought to be a support for the endothelial cells, functioning as a cytoskeleton.

Actin Cytoskeleton↗
PubMed1985

Age-induced changes in the aortas of rats.

In order to elucidate changes due to age in blood vessels, the aortic walls of Wistar rats ranging in age from 35 to 45 months were examined with an electron microscope. The remarkable changes of the walls were found mainly in the media: smooth muscle cell necrosis, increase of ground substances, as well as collagen fibrils, and calcification in some of the necrotic muscle cells. Branched smooth muscle cells were often found in the media. Elastic networks in the media, however, were hardly ever destroyed. The spider-web fashion in the peripheral cytoplasm of the smooth muscle cells was observed in all animals. Diffuse or localized slight intimal thickening could be seen in the subendothelial spaces, but aortic atherosclerosis was not present in the intima. No remarkable changes were seen in the adventitia.

Aging↗
PubMed1982

Ultrastructural observations on bifurcations in rat cerebral arteries. 2. Rats with long-term hypertension.

The bifurcation pads ("valve-like projections") in the anterior cerebral arteries of rats with long-term hypertension were studied electron microscopically. The rats ranging in age from 2 to 10 months were sacrificed after bilateral renal artery constriction at 5-week-old. In the bifurcation pads (intimal pads) of hypertensive rats, smooth muscle cell damage first appeared in the roots of the pads as well as underlying media in the form of granular, vesicular, and somewhat tubular structures (200-1500 A in diameter). Thereafter, with a lapse in time after the operation, these abnormal substances increased around the smooth muscle cells which were arranged in the marginal zones of the pads. Deeply arranged intimal smooth muscle cells which were embedded in an abundance of ground substances were only damaged in rats with very long-term hypertension. The medial smooth muscle cells beneath the pads manifested lesions which were more marked and diffuse than in the intima. These smooth muscle cells were bizarrely atrophied and abnormal substances which might be derived from necrotic smooth muscle cells were found around them. Basement membrane-like substances, either thick or multilaminated, were also present around them.

Animals↗
PubMed1981

Further observations on age-induced changes of cerebral arteries in rats. An electron microscopic study.

Proximal segments of the cerebral arteries of aging rats ranging in age from 35 to 45 months were studied electron microscopically. Characteristic features of the medial smooth muscle cells showed single or multiple cytoplasmic focal degradations with electron density, and irregularly shaped and sized cytoplasmic small cave formations (foveations) similar to a spider's web. The latter was a characteristic feature in very old rats. Intercellular spaces were dilated with an increase in amount of basement membrane-like substances, either thick or multilaminated around the bizarrely atrophied smooth muscle cells. Bundles of filaments were present in the basal cytoplasm of the endothelial cells. Bifurcation pads ("Valve-like projections") at the branching points of the cerebral arteries also showed a smooth muscle cell necrosis with deposition of basement membrane-like substances and granulo-vesicular profiles around them, especially in the roots and margins of the bifurcation pads.

Aging↗
PubMed1981

Ultrastructural study of hemangiomas. 1. Capillary hemangioma of the skin.

The fine structure of capillary hemangiomas from the skin of six young adults was investigated. All the vessels had non-fenestrated endothelial cells. Their intercellular junctions had tight junctions, but desmosome-like structures were also present. Cytoplasmic filaments (50-100A in width) as well as microtubular bodies were present in some of the endothelial cells. The bodies were approximately 0.1 micron in diameter and up to 0.5 micron in length. Subendothelial basement membrane was present and sometimes multilaminated. Pericytes had a feature of endothelial cells, fibroblasts, or smooth muscle cells. "Fibrous long-spacing collagen fibrils" (periodicity: 700-1500A) were seen in the vicinity of pericyte basement membranes or in the intervascular spaces.

Adolescent↗
PubMed1981

Ultrastructural study of hemangiomas. 2. Benign hemangioendothelioma of the hard palate.

A case of benign hemangioendothelioma which occurred in the hard palate was observed and its electron microscopic findings were described. The endothelial cells contained an abundance of cytoplasmic filaments, but they contained a small number of Weibel-Palade bodies. Two types of endothelial cells, light and dark, were found in our specimen. The former had a cytoplasm with an abundance of ribosomes, rough endoplasmic reticulum and scant filaments. The latter had a cytoplasm with numerous cytoplasmic filaments and a well-developed Golgi apparatus. Tight junctions were seen between the endothelial cells. The majority of the pericytes were accompanied with the vessels in the tumor. Three types of pericytes were recognized: endothelial cell-like, fibroblast-like, and smooth muscle cell-like pericytes.

Adolescent↗