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Biomedical subjects

A Furuta

Publications and source records attributed to A Furuta.

At least 55 records · Page 3Linked to original sources
PubMed1994

Immunohistochemical and ultrastructural study of hepatic sinusoidal linings during dichloropropanol-induced acute hepatic necrosis.

An acute phase of severe hepatic necrosis induced by dichloropropanol was examined immunohistochemically and ultrastructurally, in order to study chronological changes of sinusoidal morphology during acute hepatic injury. Male Wistar rats were injected with 1,3-dichloro-2-propanol (DC2P) and sacrificed at various intervals after the injections. DC2P-injected rats showed zonal necrosis of the centrilobular space with a peak from 24 to 48 h after the injection. Destruction of sinusoidal linings appeared at 4 h, and was gradually aggravated along the advancing hepatocytic necrosis. Monocytic influx into the necrotic areas was initiated at 6 h. At 48 h, collapsed centrilobular spaces showed a loss of most sinusoidal structures with active phagocytosis of macrophages, proliferation of perisinusoidal cells, and accumulation of collagen fibrils. At 72 h, there were many regenerating sinusoidal structures, which were composed of rather thick and less fenestrated endothelium and underlying multilayered processes of mesenchymal cells, along the regenerating hepatocytes. In these areas, occasional junctions between regenerating hepatocytes and mesenchymal cells were seen. Reconstruction of sinusoidal linings was closely related to the hepatocytic regeneration, and a hepatocytic-mesenchymal interaction might participate in this morphodynamic course of the sinusoidal reconstruction.

Acute Disease↗
PubMed1994

[Intraductal spread of carcinoma: a risk for breast conserving surgery].

Intraductal spread of carcinoma (ISC) was defined as "DCIS clearly present extending beyond terminal duct-lobular unit, or present prominently within large ducts," using a sequential slicing of tissues and 3-D reconstruction of tumors. We then analyzed the relationship between ISC in specimens obtained by breast conserving surgery (BCS) and carcinoma residue in specimens obtained by total mastectomy. We found a strong correlation between the ISC factor in BCS tissues and the carcinoma residue in mastectomy specimens. Among 12 patients under observation without mastectomy, 3 patients subsequently developed breast carcinoma. Two of the 3 patients demonstrated ISC in BCS specimens. One of 10 patients without ISC, however, developed carcinoma, suggesting that the ISC is a risk factor in breast conserving surgery for breast cancer patients.

Adult↗
PubMed1993

[Neurotoxicity of methyl bromide--neuropathologic evaluation--preliminary study].

Methyl bromide exposure produces disorders of the central and peripheral nervous system. In the literature, there are many neuropathologic studies on the nervous system, especially on the central nervous system, of experimental animals intoxicated with methyl bromide presented. However, in our opinion, a variety of lesions of the nervous system described in the human methyl bromide intoxication have not been well reproduced in the experimental animals. In this study, male Wistar rats were subjected to a 6-hour exposure a day to methyl bromide at a concentration of 500 or 290 ppm 3 days a week for 3 to 8 weeks. The systematic neuropathologic studies of their central and peripheral nervous systems were carried out to reproduce the nervous system lesions in the human methyl bromide intoxication hitherto not produced in the experimental animals. Among the rats exposed to methyl bromide at a concentration of 500 ppm for 10 to 18 days, the axonal degeneration of myelinated fibers at the cervical level of the fasciculus gracilis, which probably corresponds to the degeneration of the spinal posterior column in humans, and the necrosis of the caudate-putamen and atrophy of neurons and pallor of the neuropile in caudate-putamen, thalamus and cingulate cortex, which probably correspond to the degenerative findings of the cerebrum in humans, were found. The rats exposed to methyl bromide at a concentration of 290 ppm for 8 weeks (24 days) did not show any noticeable abnormalities histologically.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Sclerosing fibrous tumor of the cauda equina: a fibroblastic variant of peripheral nerve tumors?

The case of a 43-year-old man with an unusual mesenchymal tumor of the cauda equina is presented. A well-circumscribed firm tumor was found in the lower spinal canal at L1 level. Although a nerve root was involved, the adjacent dura mater or filum terminale was unrelated to the tumor. Microscopically, the tumor was rich in collagen and made up of irregularly intertwining fascicles of fibroblastic spindle cells lacking in nuclear atypia or mitotic activity. Partial broad hyalinization of collagen was another histological feature of the tumor. Histological and immunohistochemical studies failed to reveal any findings that suggested known fibrous neoplasms, such as schwannoma, neurofibroma and meningioma, originating in the nervous system. Ultrastructural features of the tumor cells were consistent with those of fibroblasts. Hence, the present tumor is regarded as a unique pure fibroblastic tumor (fibroma) derived from the interstitium of a nerve root in the cauda equina.

Adult↗
PubMed1993

Submassive hepatic necrosis induced by dichloropropanol.

A hitherto undescribed industrial liver injury of fulminant form induced by dichloropropanol is reported. Two middle-aged men developed severe hepatic injury just after cleaning a dichloropropanol tank at a plant producing dichloropropanol. They died from hepatic failure 4 and 11 days respectively, after carrying out the work. Liver specimens taken at autopsy from one of the cases showed submassive hepatic necrosis. This accident prompted us to undertake an experimental study in rats of intraperitoneal one-shot injection of two isomeric substances of dichloropropanol, that is, 2,3-dichloro-1-propanol (DC1P) and 1,3-dichloro-2-propanol (DC2P). Saline was injected into the control rats. One, two, four, six, 24, 48, 72 h, and 1 week after the injection, rats in each group were sacrificed. Neither control nor DC1P-injected rats showed significant biochemical or histopathological abnormalities. DC2P-injected rats revealed elevations of transaminase from 6 h after the injections, and submassive necrosis of the liver was observed in many rats. It was concluded that the severe liver injuries in both the human cases and rats in our study were caused by DC2P.

Adult↗
PubMed1993

[Full thickness chest wall resection for recurrent breast cancer with reference to prognostic factors].

Full thickness chest wall resection surgery has been carried out in 16 patients with local recurrence after previous mastectomy. Seven of 16 patients had isolated chest wall recurrence, but 9 had mediastinal invasion and/or distant metastasis of carcinoma. Recurrent breast carcinoma involving the bony chest wall was resected, and the chest wall defects were reconstructed with myocutaneous flaps using rectus abdominis or latissimus dorsi, or breast flap. Marlex mesh was utilized under the flap in 10 patients. The 3 year survival probability was 79% and the 5 year one was 57% with mean follow-up period of 43 month. Local recurrence was classified into 3 types according to cancer infiltration; i.e., demarcated, scattered and diffuse types. The patients with demarcated type showed better prognosis than those with diffuse type. Patients who received curative surgery showed better prognosis than those receiving palliative surgery. A disease free interval (DFI) after mastectomy longer than 5 years correlated well with a long survival rate after chest wall resection. Thus, local recurrence presenting demarcated tumor with possible curative surgery as well as a longer DFI after mastectomy is a favorable prognostic factor for full thickness chest wall resection.

Adult↗
PubMed1992

Does methylmercury intoxication induce arteriosclerosis in humans? A pathological investigation of 22 autopsy cases in Niigata, Japan.

In order to clarify whether or not arterio- and/or arteriolosclerosis is induced or exacerbated in patients with methylmercury (Me-Hg) intoxication, the pathological features of arteries and arterioles in specific areas in 22 patients and 36 control subjects were examined qualitatively and quantitatively. Vessels investigated were: (1) small arteries and arterioles in the subarachnoid space and cortex of the postcentral gyrus, transverse temporal gyrus, first visual area and cerebellar vermis, as well as the myocardium and renal cortex; (2) the lateral striate artery; (3) the internal carotid, anterior, middle and posterior cerebral, basilar and vertebral arteries, as well as the coronary and renal arteries; and (4) the aorta. The arteriosclerotic changes observed in the patients with Me-Hg intoxication were indistinguishable both qualitatively and quantitatively from those of controls. The results indicate that Me-Hg intoxication does not induce or exacerbate sclerotic changes in arteries and arterioles. Thus, the peculiar neurological symptoms and neuropathological features of Me-Hg intoxication are thought to be induced not by ischemia but by selective primary degeneration of the neurons in specific regions.

Adult↗
PubMed1992

Reconstitution of shunted mantle in experimental hydrocephalus.

The morphological mechanism of the reconstitution of shunted mantle was studied histopathologically in 22 kaolin-treated hydrocephalic puppies. A remarkable attenuation of cerebral mantle to less than 1 cm in thickness was seen on computerized tomography (CT) scans of four animals sacrificed 1 to 2 months after kaolin treatment (preshunt group). Ventricular shunting resulted in successful recovery of the mantle on repeated CT scans obtained 1 to 2 months after shunting in seven animals (postshunt group). In the remaining 11 animals the cerebral mantle, which had been reduced to 4 mm in thickness prior to shunting, failed to recover even 2 months after the procedure (shunt-refractory group). On gross inspection, the preshunt specimens showed marked thinning of the white matter, with the cortical ribbon well preserved, while the postshunt specimens consisted predominantly of thickened white matter. Histopathological examination of the attenuated white matter of the preshunt specimens showed decreased nerve-fiber density, myelin destruction with myelin regeneration and/or repair of myelin sheaths, and reactive astrocytosis, which were prominent especially in the periventricular white matter. The main findings in the reconstituted white matter of the postshunt specimens were extensive myelin regeneration of residual axons and remarkable astroglial proliferation with mesenchymal reaction, particularly at capillaries. No clear evidence of increased numbers of nerve fibers or axonal regeneration was observed. The shunt-refractory specimens showed remarkable attenuation of cortex, in which reduced numbers of neurons and loss of cortical lamination were noted, with vestigial white matter. The results indicate that astroglial proliferation with mesenchymal reaction and myelin regeneration contribute to the reconstitution of the cerebral mantle volume following ventricular shunting in this model. It is suggested that the critical factor for mantle reconstitution in chronic hydrocephalus is whether cortex is preserved.

Animals↗
PubMed1992

Temporal lobe tumor demonstrating ganglioglioma and pleomorphic xanthoastrocytoma components. Case report.

The case is reported of a 16-year-old boy with a left temporal lobe tumor composed of a ganglioglioma and a pleomorphic xanthoastrocytoma. Histologically, the tumor had two different components. One component involved the cortex of the left posterior temporal lobe and showed an aggregation of neuronal cells with an astroglial stroma. Ultrastructurally, numerous dense-cored vesicles, diagnosed as ganglioglioma, were found in the neuronal cells. The other component involved the adjacent cortex and white matter of the left anterior temporal lobe and the surrounding subarachnoid space. This was composed of pleomorphic cells with many multinucleated giant cells and occasional foamy cells. Most of the tumor cells were positive for glial fibrillary acidic protein. These features correspond well to earlier descriptions of pleomorphic xanthoastrocytoma. At 24 months following total tumor extirpation, the patient is alive and has had no evidence of tumor recurrence.

Adolescent↗
PubMed1991

Medullary arteries in aging and dementia.

We examined sclerotic changes of the medullary arteries in 110 nonneuropsychiatric patients ranging in age from the second to the ninth decades, in 20 patients with subcortical arteriosclerotic encephalopathy (Binswanger's disease), and in 20 patients with dementia of the Alzheimer type. The principal sclerotic change was fibrohyaline thickening of the wall, which began to appear during the late fourth decade, increased in incidence gradually with age, and was most severe in patients with subcortical arteriosclerotic encephalopathy. Morphometry showed that the sclerotic changes of the medullary arteries were most prominent in the frontal lobe, followed by the parietal, occipital, and temporal lobes, in both the nonneuropsychiatric and demented groups. The sclerotic rate in the frontal lobe of patients with dementia of the Alzheimer type was slightly higher than that in the nonneuropsychiatric patients (p less than 0.05) but far less than that in the patients with subcortical arteriosclerotic encephalopathy (p less than 0.001). The sclerotic rate correlated well with the degree of ischemic white matter changes as well as with blood pressure.

Adolescent↗
PubMed1991

[A case of brain metastasis of rhabdomyosarcoma in a child].

We report here a specific case of metastatic brain tumor orienting from rhabdomyosarcoma. An 11-year-old boy came to our hospital with complaints including headache, exophthalmos and tumors in the right frontal and left occipital region. 6 months previously subtotal removal of rhabdomyosarcoma in his right foot had been performed. CT scan demonstrated tumors in the right orbit, right frontal region and left occipital region. The tumors existed bilaterally in the skull and markedly enhanced by contrast medium. But the changes of the cranium were mild, only the dipole was slightly dilated. MRI showed that the tumors were extraaxial masses. Right external carotid angiogram revealed numerous tumor vessels fed by the meningeal artery. On April 3rd, biopsy was performed at the right frontal region. The tumor had spread in the epidural space but the cortical surface seemed to be intact. Histologically, the tumor consisted of small round cells and revealed multinuclear giant cells. It involved the skull bone, dura mater and subdural tissues. Accordingly the tumor was diagnosed as rhabdomyosarcoma. Although tumor increased rapidly, the intracranial region did not change remarkably. It was an interesting phenomenon. Eventually, rhabdomyosarcoma metastasized to the lung, and the patient died due to respiratory distress.

Brain Neoplasms↗
PubMed1991

A scanning electron microscopic study of postnatal development of rat peribiliary plexus.

Hepatic microcirculation in the developing stages is not fully clarified. This study aimed at clarifying the development of hepatic microcirculation, especially peribiliary vascular plexuses, in neonatal rats by corrosion cast procedures and scanning electron microscopy. Peribiliary vascular plexuses of large bile ducts at the hilus of 1-day-old rats showed a simple capillary network that directly poured into the portal vein. The hepatic artery promptly tapered down into many small branches and ended in sinusoids or capillary plexuses around portal vein branches near the hilus. Neither apparent hepatic artery branches nor peribiliary vascular plexuses were found in the peripheral areas of the liver. On the seventh day, very loose peribiliary vascular plexuses and small hepatic artery branches appeared up to the peripheral portal tracts, and the peribiliary vascular plexuses of large bile ducts were still capillary networks. After the seventh day, peribiliary vascular plexuses of large and medium-sized portal tracts often poured into side branches of the portal vein rather than directly into the portal vein as shown in the rats from the first day mentioned above. Peribiliary vascular plexuses of the large bile duct in 2-week-old rats showed a double layer, that is, an outer layer composed of arteries and veins and an inner layer of capillary vessels, that resembled peribiliary vascular plexuses of adult livers. After nearly 4 wk, hepatic microcirculations had almost fully developed into those of adult rats. It was concluded that the gradual postnatal development of the hepatic arterial system and the peribiliary vascular plexuses occurred in parallel with the maturation of the intrahepatic biliary trees.

Aging↗
PubMed1989

[Modulation of the jaw muscle activity during the rhythmical jaw movement by stimulation of the cortical masticatory area and amygdala in the rabbit].

The effect of each stimulus pulse to the digastric and masseter muscles activities was examined during the rhythmic jaw movement evoked by repetitive electrical stimulation of the cortical masticatory area and amygdala in the rabbit. The stimulus pulse evoked facilitation and suppression in the digastric muscle activity, and suppression and slight facilitation in the masseter muscle activity. No obvious difference in the pattern of the modulation was appeared between the stimulation of the anterior and posterior cortical masticatory area in the digastric muscle activity. In masseter muscle, the stimulation of the anterior cortical masticatory area showed remarkable suppression only, whereas the stimulation of the posterior cortical masticatory area evoked both suppression and facilitation. Lager motor units were received conspicuous modulation than smaller motor units in both muscles. The time course of these modulation was resembled with those of the masseteric and digastric reflexes by stimulation of the cortical masticatory area. We concluded that the modulation evoked by repetitive electrical stimulation of the cortical masticatory area might be occurred by stimulation of the same pathway as evoking the modulation of reflexes. The repetitive electrical stimulation of the amygdala induced rhythmical jaw movement. In the digastric and masseter muscles, the stimulus pulse evoked facilitation, whereas no obvious suppression was appeared. Lager motor unit was modulated remarkably than smaller unit.

Amygdala↗
PubMed1989

[MR imaging of the inner ear; findings of Ménière's syndrome].

Symptoms in Ménière's disease are explained by hydrops of endolymphatic system with recurrent ruptures of the membranous labyrinth. The primary cause of the increased endolymphatic volume appears to be an imbalance between secretion and resorption of endolymph which may be due to an obstruction of the endolymphatic duct and sac, located in the vestibular aqueduct. Non-visualization or narrowing of the vestibular aqueduct of the paper have been demonstrated by conventional tomography and high resolution computed tomography (HR-CT). But the endolymphatic duct and sac can not be obtained by HR-CT and conventional tomography. Whereas, on MRI, these are identified. By MRI, we prospectively tried to demonstrate morphological alterations in 10 patients with Ménière's disease and in 4 patients with vestibular neuronitis. These were compared with a group of 20 normal men. Visualization of the endolymphatic duct and sac (vestibular aqueduct) on MRI was assessed. There was a distinctly decreased visualization of the vestibular aqueduct in the Ménière group and vestibular neuronitis group. We were able to confirm a statistically proven usefulness of the MRI technique in identifying an anatomical abnormality which is directly in correlation with the side of the lesion in cases of unilateral Ménière's disease.

Adult↗
PubMed1989

[Reset of masticatory rhythm evoked by stimulation of the cortical masticatory area].

The rhythmical jaw movement can be evoked by repetitive electrical stimulation of the cortical masticatory area in various animals. However, the relationship between evoked jaw movement and each stimulus pulse applied to the cortical masticatory area has not been clarified. The present study examined the effects of each stimulus pulse for evoked masticatory rhythm in urethan anesthetized rabbits. The repetitive electrical stimulation applied to the cortical masticatory area not only evoked rhythmic jaw movement but reset the rhythmic cycle. The application of stimulus pulses till about 70 msec after starting point of the cycle in 4.1 Hz stimulation and till 50 msec in 8.2 Hz stimulation did not reset the cycle length. After these non resetting time, the first stimulus pulse reset the cycle length, and the following any stimulus pulse did not reset the cycle length. When the stimulus pulse reset the cycle length, the length from the applied point of stimulus to the end of cycle was stable: about 184 msec in 4.1 Hz stimulation and 199 msec in 8.2 Hz stimulation. Therefore, the length of basic cycle would be about 250 msec (184 msec + 70 msec = 254 msec in 4.1 Hz stimulation, 199 msec + 50 msec = 249 msec in 8.2 Hz stimulation). This basic cycle length coincided with the shortest cycle length of the rhythmical jaw movement evoked by the most effective stimulation of the cortical masticatory area.

Animals↗