Search PubMed⌕ Search

Biomedical subjects

T Yoshimine

Publications and source records attributed to T Yoshimine.

At least 163 records · Page 9Linked to original sources
PubMed1989

[Astrocytic proliferation in the brain adjacent to infarcted lesion: immunohistochemical study of astroprotein (GFAP) and bromodeoxyuridine (BrdU)].

Although cerebral infarction is a destructive process of nerve cells and brain tissue, the nature is not exclusively disintegrating but also includes active cellular reaction which may modify the progression of tissue damage. Most prominent cellular reaction in the area surrounding infarction can be recognized as a trophic or proliferative change of glial cells. In the present study we produced a focal cerebral ischemia in Mongolian gerbils and investigated the dynamic change of astrocytes in the brain adjacent to thalamic infarction. Using immunohistochemical methods, astrocytes were identified with the antibody to astroprotein (GFAP) and the DNA synthesizing (S phase) cells were detected with the antibody to bromodeoxyuridine (BrdU). The posterior communicating artery of a gerbil was occluded by coagulation through the trans-tympanic bulla approach under general anesthesia with ketamine hydrochloride (80 mg/kg, i.p.). Thirty min after intravenous administration of BrdU (200 mg/kg), animals were sacrificed by transcardiac perfusion with 75% ethanol on days 1, 2, 3, 5 and 7 post-infarction. Ethanol-fixed, paraffin-embedded blocks were cut coronally into 6 microns-thick sections at the level of dorsal hippocampus. Double-labeled immunohistochemical technique (avidin biotin peroxidase-complex method) was carried out with each antibody using 3,3'-diaminobenzidine tetrahydrochloride and 4-chloro-1-naphthol as chromogens. The population of GFAP-positive cells and their S-phase fraction (the number of BrdU-positive nuclei divided by the number of GFAP-positive cells expressed in per cent, %) were examined. The data demonstrated that the regional GFAP-positive cells increased continuously between days 1 to 5 (105.9 to 528.8 cells/mm2) postinfarction (44.6 cells/mm2 in normal brain).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Extracellular purine catabolites and tissue nucleotides and purine catabolites during progression and recovery of ischemia].

During progression and recovery of ischemia, extracellular purine catabolites were measured and compared with purine catabolites and adenine nucleotide levels in the tissue. Ischemia was induced by bilateral occlusion of the common carotid arteries in gerbil. Extracellular purine catabolites were sampled by in vivo brain microdialysis technique, and tissue adenine nucleotides and purine catabolites were extracted from in situ frozen and lypholized brain tissue. These metabolites were measured with simple method of isoclatic condition by HPLC system. Ischemia depleted tissue ATP and ADP, whereas AMP and purine catabolites accumulated strikingly. In parallel, extracellular purine catabolites increased as consecutive degradation on the biochemical metabolic pathway in the same animal. Levels of tissue ATP and adenosine normalized in the recovery phase of ischemia immediately. However, extracellular purine catabolites during the recovery are much higher than those during the progression of ischemia. These data indicated extracellular high levels of purine catabolites during the ischemic insult, and especially adenosine as neuromodulator which may turn off spontaneous neuronal activity and exert antiepileptic effects during the recovery rather than the progression of ischemia.

Adenine Nucleotides↗
PubMed1988

Regional differences in inhibition and recovery of protein synthesis after transient hindbrain ischaemia of gerbils.

Regional protein synthesis was estimated autoradiographically in a model of transient hindbrain ischaemia of gerbils. In studies of 5 min ischaemia followed by 5 min recirculation, incorporation of [14C]valine into the TCA-insoluble protein fraction was not affected. In studies of 15 min ischaemia followed by 5 min recirculation, incorporation of the tracer into the protein fraction was severely depressed in the ischaemic lesion of the brain stem and cerebellum. However, the granular layer of the cerebellar cortex had partially preserved protein synthesis. When recirculation time was extended to 2 h after 30 min ischaemia, protein synthesis of the cerebellar cortex almost recovered to the full level of the control. However, in the pontine grey matter, inferior colliculus and vestibular nucleus, a significant reduction in protein synthesis persisted. These results indicate that protein synthesis in the pontine grey matter, inferior colliculus and vestibular nucleus are selectively inhibited by ischaemia. Further its recovery after recirculation is slow. The cerebellar cortex is less vulnerable to ischaemia, and recovery is relatively fast. The regional heterogeneity of protein synthesis is neither due to the degree of ischaemia in this model nor the extent of postischaemic hypoperfusion. Factors that influence protein synthesis in this ischaemic model are discussed.

Animals↗
PubMed1988

[Malfunction of gene expression as a possible cause of delayed neuronal death].

To clarify a possible cause of delayed neuronal death, synthesis of protein and ribonucleic acid (RNA) following transient forebrain ischemia was evaluated autoradiographically. Mongolian gerbils were subjected to transient forebrain ischemia for 5 minutes by occluding bilateral common carotid arteries. They were used for autoradiographic study at 1, 2, and 5 days after ischemia. Tracer dose of 14C-valine or 14C-uridine was injected intravenously, and animals were sacrificed 45 minutes thereafter. Brains were frozen and thin sliced for macroautoradiography. After the first autoradiogram was obtained, tissue sections were incubated in cold 5% trichloroacetic acid for 1 hour, dried and again used for autoradiogram. With this preparation we could differentiate the tracer incorporated into protein or RNA fraction from the total tissue radioactivity. In the different set of animals, microautoradiograms of 3H-valine and 3H-uridine was obtained to detect subcellular distribution of synthesized protein or RNA. At 1 day after ischemia, protein synthesis in the CA 1 region of the hippocampus was reduced by 57% of the sham control, but RNA synthesis was not reduced quantitatively. Microautoradiogram of 3H-uridine however, indicated that silver grains in the cytoplasms of the CA 1 pyramidal cells were much reduced as compared to sham controls, though the amount of silver grains in the nucleus was the same as sham controls. Therefore, synthesized RNA in the nucleus was not transported to the cytoplasm. At 2 days after ischemia, protein and RNA synthesis was preserved to the same level as sham controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Factors affecting the prognosis of brain tumors].

A variety of tumors with different histologic types are included in a group of brain tumors. Although each histologic type of tumor has its own range of malignancy, the prognosis seems to be affected by several clinical, histologic and cell-biological factors. For example, relative survival rate of patients with glioblastoma is lower if the patient is older than 50 or 60 years. The leptomeningeal dissemination of glioma cells is a sign of poor prognosis. The presence of necrotic foci in the astrocytic tumors suggests shorter astrocytic tumors suggests shorter survival. Using a monoclonal antibody to bromodeoxyuridine (BrdU), the growth activity of the tumor can be estimated by BrdU labeling index (BrdU-LI, %). Higher BrdU-LI is correlated with more malignant histologic features in astrocytic tumors. In meningiomas, higher BrdU-LI is correlated with a more frequent or rapid recurrence of the tumor. The significance of growth factor receptors and oncogene of growth factor receptors and oncogene products as a cell-biologic marker of malignancy was investigated with an immunohistochemical method. Transferrin receptor was demonstrated in all tumors, and epidermal growth factor in about 40% of astrocytic tumors. The immunoreaction to c-myc oncogene product was detected in most astrocytic tumors; with higher intensity in anaplastic astrocytomas and glioblastomas than in low-grade astrocytomas. The role of these markers in the prognosis of brain tumors is, however, still unclear. Total or subtotal resection of glioblastoma results in longer resection of glioblastoma results in longer survival. Both postoperative radiotherapy and chemotherapy are effective. However, maintenance of chemotherapy longer than longer than 2 years does not significantly improve the prognosis.

Age Factors↗
PubMed1988

[Postnatal cell proliferation in the rat cerebrum: immunohistochemical study with bromodeoxyuridine (BrdU)].

The postnatal cell proliferation in the rat cerebrum was studied immunohistochemically using a monoclonal antibody to bromodeoxyuridine (BrdU). Since BrdU, a halogenated analogue of thymidine, is incorporated into nuclear DNA during duplication, S-phase cells can be detected by demonstrating intranuclear BrdU. 200 mg/kg of BrdU was administered to normal Wistar rats intraperitoneally on the day of birth or intravenously 1, 2, 3, 5, 8 or 24 weeks after birth. Thirty minutes later, the brain was fixed by perfusion with ethanol, and the paraffin-embedded sections were processed for the avidin biotin peroxidase-complex method. BrdU-positive nuclei were counted among 500 to 10,000 cells in several regions of the brain to obtain the BrdU-labeling index (the number of BrdU-positive cells per 100 cells scored, LI, %). The present study demonstrated that (1) proliferating cells in the gray matter (cerebral cortex and caudate-putamen) are only few at birth (LI = 0.54-0.78%), which further decrease during the following few weeks, and disappear by adulthood, (2) in the white matter (corpus callosum), cell proliferation is relatively active within 1 week after birth (LI = 5.6-6.3%), but becomes inactive thereafter, (3) the proliferative activity of the cells in the subependymal layer of the lateral ventricle is very high at birth (LI = 15.5%), which somewhat decreases during the following few weeks, but still remains high in adulthood (LI = 7.5%). This kind of continued cell proliferation in the brain after birth seems important in the postnatal development of the normal cerebral structure, and in several pathologic processes such as tissue repair and the development of brain neoplasm.

Age Factors↗
PubMed1988

[Effect of ACNU against experimental brain tumor--immunohistochemical study using anti-BrdU monoclonal antibody].

We have studied the efficacy of intrathecal ACNU against experimental leptomeningeal tumors. In the present report, the effect of ACNU on the growth kinetics of the tumor was evaluated by the immunohistochemical technique using anti-BrdU monoclonal antibody. The experimental leptomeningeal tumor was developed by inoculation of Walker 256 carcinosarcoma cells into the cisterna magna of rats. Seven days after the inoculation of tumor cells, the animals were treated either by intravenous (15 mg/kg) or intrathecal (1.5 mg/kg) ACNU. Four, 12, 24, 48, 96 or 144 hours after treatment, the animals received intravenous BrdU (200 mg/kg). Thirty minutes thereafter, they were sacrificed and the brain was removed. L. I. was calculated by counting the immunoreactive tumor cells. L. I. of the tumor without treatment on the seventh day after inoculation was over 40%. L. I. began to decrease 24 hours after intravenous ACNU, and remained 11% up to 96 hours. On the other hand, L. I. already decreased to 20% 4 hours after intrathecal ACNU and remained to be low (17%) up to 48 hours. However, L. I. increased to 38% at 96 hours. Thus, the effect on the growth kinetics of the tumor differs between intravenous and intrathecal ACNU. These results are considered to be useful informations for determining the optimal dosage of the antineoplastic agent against the brain tumor and developing the effective combination chemotherapy.

Animals↗
PubMed1988

[S-adenosyl-L-methionine concentration in cerebral interstitial fluid monitored by intracerebral microdialysis].

Ketamine-anesthetized gerbils were implanted with 0.5 mm diameter microdialysis tubing through the cortex, hippocampus and thalamus with a stereotaxic instrument. The cannula was perfused with artificial cerebrospinal fluid at a flow rate of 2 microliters/min. Samples of the perfusate representing the cerebral interstitial fluid were collected and subsequently analyzed for their content of S-adenosyl-L-methionine (SAM) with high performance liquid chromatography (HPLC). In vitro tests using the dialysis cannula gave SAM recovery which varied from 3.44 +/- 0.31% (n = 3) at a perfusion flow rate of 8 microliters/min to 43.8 +/- 3.81% (n = 3) at 0.5 microliters/min (mean +/- SEM). The in vivo SAM content of the perfusate was studied and the endogenous SAM level in cerebral interstitial fluid of gerbil was 3.49 +/- 1.52 nmol per ml (n = 3). Intraperitoneal injection of SAM (250 mg/kg) produced 10-fold increases in the perfusate SAM concentration. After the experiment the brains were checked by immunopathological study using anti-albumin antibody to examine the degree of damage to the blood-brain barrier permeability. These results show that intracerebral microdialysis offers several potential advantages for studies of extracellular neurochemistry.

Animals↗
PubMed1988

[Growth activity of meningeal carcinomatosis--immunohistochemical study using anti-BrdU monoclonal antibody].

We have developed an experimental model of leptomeningeal tumor by inoculating Walker 256 carcinosarcoma cells into the cisterna magna of rats. This model was considered to be useful in studying pathophysiology and treatment of malignant brain tumors. In this study, the growth kinetics of this experimental tumor was investigated by using the immunohistochemical technique with an anti-BrdU monoclonal antibody. Walker 256 carcinosarcoma was subcutaneously passaged in female Wistar rats. Seven days after subcutaneous inoculation, the tumor was aseptically removed and minced in Hank's medium by scissors to make single cell suspension of the tumor. The cell suspension was adjusted to 1 x 10(5) cells/ml. And 0.1 ml was inoculated percutaneously into the cisterna magna of female Wistar rats weighing 150 gr. Every day after tumor inoculation, the animal (5 on each day) was sacrificed 30 minutes after intravenous BrdU (200 mg/kg) and perfused by saline. Then, the brain was removed, fixed in ethanol and embedded in paraffin. Coronal sections of the brain 6 mu in thickness were cut and stained by the indirect immunoperoxidase (ABC) method. The anti-BrdU monoclonal antibody (Becton-Dickinson) was diluted in 1:100. The sections were counterstained by hematoxylin. Labelling index (L.I.) of the tumor was obtained by counting immunoreactive cells under the microscope. L.I. of the subcutaneous tumor 7 days after inoculation was 52.4%. In the tumor 1 to 3 days after inoculation, L.I. was still low and between 11.9 and 15.1%. Four or 5 days after inoculation, the tumor cells grew in several layers in the subarachnoid space. L.I. at this stage of the tumor growth was 26.6 to 34.8%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Intermediate filaments and anaplastic change of ENU-induced gliomass: immunohistochemical study with vimentin and astroprotein (GFAP).

To study the expression of two different subclasses of intermediate filaments in ethylnitrosourea-induced rat cerebral gliomas, the number of cells immunopositive for each subunit protein, vimentin and astroprotein (GFAP), was quantitatively analyzed. Vimentin is a subunit protein of non-specific intermediate filaments which appear transiently in immature glial cells, while astroprotein (GFAP) is a subunit protein of glial filaments, normally expressed in mature astrocytes. Although most normal astrocytes were negative for vimentin, many tumor cells showed weak to strong immunoreaction for vimentin. The expression of vimentin was more frequent and intense in anaplastic forms of gliomas than in benign forms. Accordingly, the vimentin/GFAP ratio [the number of vimentin-positive cells divided by the number of astroprotein (GFAP)-positive cells] was increased from 0.23 to 1.86, and from 0.26 to 1.85, respectively, as oligodendrogliomas and mixed gliomas become anaplastic. The present study demonstrated that the immunohistochemical study for those two subclasses of intermediate filaments can provide important informations on the cell biological nature of glial tumors.

Anaplasia↗
PubMed1987

Pathology of brain parenchyma in meningeal carcinomatosis; immunohistochemical study with astroprotein (GFAP) and tubulin.

Effects of leptomeningeal tumor on the brain parenchyma was studied by the immunohistochemical method with astroprotein (GFAP) and tubulin in a rat model of meningeal carcinomatosis. Thickening of subpial glial lining (external glial layer) and hypertrophy of subpial astrocytes, detected by the antiserum to GFAP, was the early sign of parenchymal involvement. The glial lining was continuous as far as the tumor cells were confined to the subarachnoid space, however, penetration of tumor cells into subpial brain was associated with disruption of the glial lining. Speculative role of this lining in preventing the tumor cell to infiltrate into brain tissue was discussed. In contrast to the prominent immunohistochemical changes in astrocytes, neuronal tubulin immunoreactivity was not altered even in the late stage of the disease. The present study demonstrated that the leptomeningeal dissemination of tumor cells did cause pathologic change in brain parenchyma as was evidenced by the reactive change of astrocytes. However, the preserved immunoreaction for tubulin suggested that the nerve cell damage was not severe even at the advanced stage of the disease.

Animals↗
PubMed1987

Autoradiographic study of regional protein synthesis in focal cerebral ischemia with TCA wash and image subtraction techniques.

The standard biochemical method of trichloracetic acid (TCA) wash and the image processing technique were combined to differentiate and visualize the distributions of polypeptide-incorporated and unincorporated tracers in an autoradiographic study of regional protein synthesis. The validity of applying TCA wash procedures to cryostat sections was considered by histologic and chemical evaluations. For the autoradiographic study of in vivo protein synthesis, a tracer dose of L-[14C]valine was administered 30 min after occlusion of the posterior communicating artery in gerbils. Images of total (polypeptide-incorporated and unincorporated) radioactivity and of polypeptide-incorporated radioactivity were obtained from an identical cryostat section before and after TCA wash. The polypeptide-unincorporated radioactivity image was produced with an image processing system by subtracting pixel by pixel the polypeptide-incorporated radioactivity from the total radioactivity. The present study clearly demonstrated that in spite of the sufficient delivery of tracer amino acids, the polypeptide synthesis was completely lost in the ischemic focus. Free tracer was markedly accumulated in the brain adjacent to the ischemic focus. This kind of autoradiographic technique seems to be indispensible in studying the topographical complexity of the altered protein metabolism in the pathologic brain.

Animals↗
PubMed1987

Glioblastoma after radiotherapy for craniopharyngioma: case report.

A 6-year-old girl developed a glioblastoma in the basal ganglia and brain stem 5 years after surgical excision and local irradiation (5460 cGy) for craniopharyngioma. Clinical and histological details are presented, and the literature on radiation-induced gliomas is reviewed.

Basal Ganglia↗
PubMed1987

Malignant recurrence of childhood cerebellar astrocytoma: case report.

A 15-year-old boy developed a glioblastoma in a cerebellar hemisphere 7 years after surgical excision and local irradiation of a pilocytic astrocytoma in the cerebellar vermis. Clinical and histopathological details are presented, and the literature on late malignant recurrence of childhood cerebellar astrocytoma is reviewed.

Adolescent↗
PubMed1987

Intraoperative measurement of cortical blood flow and its CO2 response in childhood moyamoya disease.

Cortical blood flow was monitored during craniotomy for bypass surgery to treat childhood moyamoya disease. The patients were hyperventilated, and changes in cortical surface blood flow were detected by a heat clearance method with plate type thermocouple probes. End-tidal CO2 was monitored during hyperventilation to avoid excessive reduction of CO2. There were three types of blood flow responses to hyperventilation: simple reduction, prolonged reduction, and increase. Simple reduction was noted in four cases and was related to constriction of basal and ethmoidal moyamoya vessels. Prolonged reduction was noted in three cases and was related to excessive constriction of basal moyamoya vessels. Increase was noted in four cases and was related to increase in blood flow from cranial vault moyamoya vessels. The results indicate that the basal moyamoya vessels are constricted by hyperventilation. This may be the cause of ischemic symptoms provoked by hyperventilation.

Adolescent↗
PubMed1987

Immunohistochemical investigation of cerebral ischemia after middle cerebral artery occlusion in gerbils.

Progression and recovery of ischemic and postischemic damage after occlusion of the middle cerebral artery and subsequent reperfusion were investigated in the gerbil. This study was performed by immunohistochemical reaction testing for tubulin and creatine kinase BB-isoenzyme to visualize the neuronal structure and by immunohistochemical reaction testing for astroprotein (an astrocyte-specific protein) to visualize reactive astrocytes. The earliest ischemic lesion became visible in the frontoparietal cortex after 7 minutes of ischemia as a laminar loss of the reaction for tubulin involving the neuropil, neuronal perikarya, and dendrites. The earliest lesion in the caudoputamen evolved after 30 minutes of ischemia. After reestablishment of cerebral circulation, the immunohistochemical ischemic lesions in the neuronal structure disappeared if the ischemic period was 10 minutes or less and partially disappeared even after ischemia for 15 minutes in the cerebral cortex, while the postischemic lesion in the caudoputamen disappeared even after ischemia for 15 minutes. Reactive astrocytes were detected in the cerebral cortex and caudoputamen as early as 24 hours after reperfusion, both in the areas with and without the neuronal lesions. No lesion was identified in the hippocampus or thalamus. This experimental model is suitable for investigation of rapidly progressive regional ischemia in the cerebral cortex and for comparison with other regional or global cerebral ischemia in the gerbil or other animal species.

Animals↗
PubMed1987

[Changes in protein and RNA synthesis following acute hindbrain ischemia].

Protein and RNA synthesis of the brain is affected by focal transient ischemia. Protein synthesis is depressed by the depletion of energy metabolism during ischemia, and its recovery following recirculation is slower than restoration of energy metabolism. On the other hand, RNA synthesis is more tolerable to ischemia than protein synthesis. Present study has designed to evaluate changes of protein and RNA synthesis of the brain after ischemia. We used a hindbrain ischemia model of gerbils, and quantitative autoradiography was applied for estimation of regional protein and RNA synthesis. The model was made by occluding the basilar artery for 15 minutes and recirculating afterwards. 14C-valine was used as a tracer for protein synthesis. In the ischemic group, protein synthesis was inhibited extremely in the medial thalamus, inferior colliculus, gray matter of the pons and midbrain, and cerebellum, RNA synthesis by salvage pathway was evaluated using tracer doses of 14C-uridine. It increased 1.6-2.4 folds of sham controls in the thalamus, and gray matter of the pons and midbrain. De novo synthesis of RNA was evaluated using 14C-carbamoylphosphate and 14C-NaHCO3. 14C-NaHCO3 antoradiogram showed inhibition of tracer incorporation into RNA and protein fraction in the ischemic lesions. 14C-carbamoylphosphate autoradiogram showed no significant change. These results indicate that protein synthesis is inhibited after ischemia but response of RNA synthesis to ischemia is not uniform. De novo synthesis of RNA is inhibited following ischemia, but RNA synthesis by salvage pathway increases in the ischemic lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗