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Biomedical subjects

J Shinoda

Publications and source records attributed to J Shinoda.

At least 73 records · Page 4Linked to original sources
PubMed1995

Effect of platelet-derived growth factor on phosphatidylcholine-hydrolyzing phospholipase D in osteoblast-like cells.

We examined the effect of platelet-derived growth factor (PDGF) on the activation of phosphatidylcholine-hydrolyzing phospholipase D in osteoblast-like MC3T3-E1 cells. PDGF-BB stimulated both the formation of choline (EC50 = 15 ng/ml) and inositol phosphates (EC50 = 5 ng/ml). However, PDGF-BB had little effect on the formation of phosphocholine. The formation of choline stimulated by a combination of PDGF-BB and 12-O-tetradecanoylphorbol-13-acetate, a protein kinase C (PKC)-activating phorbol ester, was additive. H-7, an inhibitor of protein kinases, inhibited 12-O-tetradecanoylphorbol-13-acetate-induced choline formation, whereas HA1004, a control for H-7 as PKC inhibitor, had little effect. Neither H-7 nor HA1004 affected the PDGF-BB-induced formation of choline. Genistein and methyl 2,5-dihydroxycinnamate, inhibitors of protein tyrosine kinases, dose dependently inhibited the PDGF-BB-induced formation of choline. PDGF-BB stimulated Ca2+ influx from extracellular space. PDGF-BB-induced choline formation was significantly reduced by chelating extracellular Ca2+ with EGTA. PDGF-BB stimulated DNA synthesis of MC3YT3-E1 cells, and H-7 inhibited the DNA synthesis. These results strongly suggest that PDGF activates phosphatidyl-choline-hydrolyzing phospholipase D independently from PKC activated by phosphoinositide hydrolysis in osteoblast-like cells, and that both tyrosine kinase activation and Ca2+ influx are essential for this mechanism.

Animals↗
PubMed1995

Mechanism of phospholipase D activation induced by extracellular ATP in osteoblast-like cells.

We have previously reported that extracellular ATP stimulates Ca2+ influx from extracellular space, resulting in the production of prostaglandin E2 which mediates, at least in part, its proliferative effect on osteoblast-like MC3T3-E1 cells, and that the activation of protein kinase C (PKC) stimulates phospholipase D in these cells. In the present study, we examined the effect of extracellular ATP on phosphatidylcholine-hydrolysing phospholipase D activity in MC3T3-E1 cells. ATP stimulated the formation of both choline and inositol phosphates dose-dependently in the range between 0.1 and 1 mM. The formation of choline by a combination of ATP and NaF, an activator of GTP-binding protein, was synergistic, whereas that of inositol phosphates was not. A combination of ATP and 12-O-tetradecanoylphorbol-13-acetate, a PKC activating phorbol ester, additively stimulated the formation of choline. Staurosporine, an inhibitor of PKC, had little effect on ATP-stimulated formation of choline. Choline formation was significantly reduced by chelating extracellular Ca2+ with EGTA, while being inhibited by W-7, an antagonist of calmodulin. These results suggest that extracellular ATP stimulates phospholipase D in a Ca2+/calmodulin-dependent manner in osteoblast-like cells, and that neither PKC activation nor GTP-binding protein is involved in this mechanism.

Adenosine Triphosphate↗
PubMed1995

Ruptured dissecting aneurysm of the peripheral anterior cerebral artery--case report.

A 27-year-old male presented with intracranial hemorrhage due to rupture of an idiopathic dissecting aneurysm in the A4 segment of the left anterior cerebral artery (ACA). This is a very rare location. He was successfully treated by resection of the aneurysm without neurological deficits. Surgical intervention is recommended for patients with intracranial hemorrhage due to ruptured dissecting aneurysm of the ACA to prevent rebleeding.

Adult↗
PubMed1994

Symptomatic middle cerebral artery stenosis and occlusion: comparison of three-dimensional time-of-flight magnetic resonance angiography with conventional angiography.

The usefulness of magnetic resonance (MR) angiography using the three-dimensional time-of-flight method for the characterization of symptomatic middle cerebral artery (MCA) occlusive lesions was evaluated in 10 patients with MCA occlusion and 10 with MCA stenosis. All lesions were symptomatic and documented by conventional angiography. There was no false-negative MR angiogram that failed to demonstrate the MCA occlusive lesion. MR angiography correctly evaluated the location of lesions and the difference between stenosis and occlusion. Stenosis appeared as a focal signal loss (< 1.0 cm) of the MCA at the site of stenosis, and occlusion as a complete signal loss of the MCA distal to the site of occlusion. However, MR angiography could not distinguish diffuse stenosis and one point stenosis demonstrated by conventional angiography. MR angiography is a useful noninvasive diagnostic method for evaluating occlusive lesions of the MCA in symptomatic patients.

Adult↗
PubMed1994

[A case of intracranial glioma which demonstrated extramedullary growth].

An unusual case of an intracranial glioma which demonstrated extramedullary growth is reported. The patient was a 39-year-old woman who had experienced headache, nausea and vomiting for about 1 month. On admission she showed slight disturbance of consciousness and bilateral papilloedema. CT scan and MR imaging disclosed a mass approximately 5 cm in diameter in the right frontal region, with clear demarcation from the neighboring gyri. Right external carotid angiogram revealed A-V shunts in the mass, but by right internal carotid angiogram, no abnormal findings were disclosed except for the deviation of normal intracranial vessels due to the existence of the mass. Therefore, a preoperative diagnosis of extramedullary tumor such as meningioma and epidermoid was made. Right frontal craniotomy was performed, and the tumor was proven to exist in subdural space. The boundary of the tumor to the brain surface was distinct except for one part. Histopathologically, the tumor cells had abundant eosinophillic cytoplasms, with eccentric-distribution of their nuclei. Furthermore, they were positive for staining for GFAP and S-100 protein. Therefore, a final diagnosis of gemistocytic astrocytoma was made. Reviewing some references the authors discuss here the form of development and progression of intracranial gliomas which demonstrate extramedullary growth such as this case.

Adult↗
PubMed1994

[Qualitative evaluation of 123I-IMP SPECT using a rotating gamma camera in atherosclerotic large-artery disease].

PURPOSE Quantitative measurement of regional cerebral blood flow (rCBF) needs special equipment or invasive blood sampling. Therefore, with a popularly used rotating gamma camera, we tried to establish a convenient modality of qualitative evaluation of hemodynamics in patients with atherosclerotic large-artery disease, according to the distribution pattern of isotope-uptake on SPECT image. PATIENTS AND METHODS Forty-one patients with atherosclerotic large-artery disease [9 internal carotid artery (ICA) stenosis, 17 ICA occlusion, 8 middle cerebral artery (MCA) stenosis, and 7 MCA occlusion] and 32 control patients documented as having small cerebral infarction without atherosclerotic large-artery disease were investigated. Using the rotating gamma camera, they underwent 123I-IMP SPECT at baseline and after acetazolamide loading. According to the distribution pattern of low isotope-uptake, early images were classified into four types: Type I: no low uptake, Type II: low uptake in a single watershed, Type III: low uptake in two watersheds with or without a partial MCA territory, Type IV: low uptake in a whole MCA territory. RESULT In patients with large-artery disease, baseline images presented Type I in 12 cases, Type II in 16, Type III in 9, Type IV in 4, and loading images Type I in 3, Type II in 2, Type III in 8, Type IV in 28. Of 37 patients except for 4 belonging to Type IV at baseline, 32 (86.5%) had a more extensive low isotope-uptake area after acetazolamide loading than at baseline. In control patients, baseline images presented Type I in 25, Type II in 7, and the Type III & IV in 0, and the Type after loading was the same as the Type at baseline. CONCLUSION We established the qualitative evaluation of 123I-IMP SPECT image by detecting the "extent" of the ischemic region, taking notice of watershed. The pathognomonic findings on SPECT image of atherosclerotic large-artery disease showed that low isotope-uptake area at baseline extended into two watersheds or MCA territory by acetazolamide loading. The modality of qualitative evaluation based on these pathognomic findings of SPECT image may be useful for easily assessing patients with atherosclerotic large-artery disease using a rotating gamma camera.

Adult↗
PubMed1994

[Cerebral cysticercosis treated with praziquantel--a case report].

We report a patient with cerebral cysticercosis treated with praziquantel. The patient, a 30-year-old man, was admitted to our hospital with a 12-year-history of generalized convulsion. MRI of the brain showed multiple cysts and the largest one in the right frontal lobe measured 3 cm in diameter. The intensity of cyst contents was same as that of the CSF on T1- and T2-weighted images. X-Ray of extremities and blood examinations showed no abnormal findings. The immunological testing for cysticercosis was negative in the serum. An operation was performed for the largest cyst in the right frontal lobe. The cyst was pathologically confirmed as cysticercosis. He was treated with praziquantel 50 mg/kg body weight in 3 divided doses per day with steroid cover for 7 days. The same therapy was repeated at an interval of 14 days. The patient was suffering from headache and scintilating scotoma only for a few days during the therapy. MRI revealed reduction in the size of the cysts in the right occipital lobe but no change in the other cysts. He was given praziquantel 600 mg per day for two months. As a result, the cysts in the right occipital lobe disappeared and the other cysts diminished on MRI.

Adult↗
PubMed1993

Primary osteosarcoma of the skull--a case report and review of the literature.

Primary osteosarcoma of the skull (POS) in a young man with intracranial involvement is reported. After an initial transient remission by surgical intervention and chemotherapy, he began to deteriorate due to tumor recurrence and intracranial hemorrhage, and died 15 months following the time of diagnosis. The rarity and poor prognosis of POS are emphasized together with the review of the clinical and therapeutic aspects in the previously reported 98 cases in the literature.

Adult↗
PubMed1993

Prediction of cerebral infarction due to vasospasm following aneurysmal subarachnoid haemorrhage using acetazolamide-activated 123I-IMP SPECT.

Prediction of cerebral infarction due to vasospasm (VS) following aneurysmal subarachnoid haemorrhage (SAH) was investigated using acetazolamide-activated (A-A) N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) single photon emission computed tomography (SPECT) in 79 SAH patients. A-A SPECT was undertaken twice or more for one each patient by Day 18. Fifty-six (71%) of the 79 patients presented with reduction of cerebral vasodilatory capacity (CVC) on SPECT due to VS by Day 18. Of the 56 patients, 29 showed CVC by Day 8 (Group A), while the other 27 first showed CVC reduction between Day 9 and 18 (Group B). Cerebral infarction on CT was revealed by Day 18 in 15 patients (52%) of Group A and 3 (11%) of Group B. Of the 56 patients, 20 showed reduced CVC in watershed[s] (Type 1), 12 in a sole territory of the intracranial major arterial trunk (Type 2), and 24 in several territories or in a sole territory with distant watershed[s] (Type 3). Cerebral infarction on CT by Day 18 was revealed in one patient (5%) in Type 1, 3 (25%) in Type 2, and 14 (58%) in Type 3. Twelve (71%) of 17 patients belonging to both Group A and Type 3 resulted in cerebral infarction. These results suggest that early and extensive CVC reduction are significant factors responsible for cerebral infarction due to VS following SAH. Cerebral infarction can be reasonably predicted using A-A SPECT in SAH patients.

Acetazolamide↗
PubMed1993

Central neurocytoma: proliferative assessment by nucleolar organizer region staining.

Proliferative potential of four cases of central neurocytoma were assessed by a silver colloid staining technique for argyrophilic protein associated with nucleolar organizer regions (AgNORs). All but one tumor had an Ag-NOR score of less than 2 and were regarded as a benign entity. However, one tumor tissue from a patient suffering from a recurrent central neurocytoma after 13 years from the first operation possessed a 2.06 AgNOR score, which is not significantly different from others. It is considered that central neurocytoma is an essentially benign neoplasm, even though the tumor is recurrent. The present study revealed the usefulness of AgNOR staining for a retrospective assessment of the proliferative potential of central neurocytomas.

Adult↗
PubMed1991

Acetazolamide reactivity on cerebral blood flow in patients with subarachnoid haemorrhage.

Cerebral vasodilatory capacity was evaluated by acetazolamide-activated N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) single photon emission computed tomography (SPECT) in 42 patients with subarachnoid haemorrhage (SAH). A low perfusion area was present in the corresponding region of haematoma seen on the CT and continued to be noted throughout the time courses. Deteriorated acetazolamide reactivity affected by surgical intervention was seen in 100% of the patients who underwent aneurysm repair in the 1st postoperative week, 92% in the second week, 73% in the third week, and 47% in the fourth week. Three patients with acute diffuse brain swelling seen on CT showed intracranial non-filling of 123I-IMP on SPECTs performed on Day 6, and all three died by Day 10. Some low perfusion areas, due to probable vasospasm, were present in 77% of Hunt and Hess grades I and II patients and in 100% of grades III, IV, and V patients throughout their time courses. Overall, low perfusion areas, due to probable vasospasm, were seen in 10 patients (31%) of 32 who underwent SPECT between Day 4 and 8,23 (77%) of 30 between Day 9 and 14, 21 (72%) of 29 between Day 15 and 21, and 11 (48%) of 23 between Day 22 and 28. The results suggest acetazolamide-activated 123I-IMP study is of value in evaluating changes in vasodilatory capacity in SAH patients in the acute and subacute stages.

Acetazolamide↗
PubMed1990

Tumors at the trigone of the lateral ventricle--clinical analysis of eight cases.

Tumors at the trigone of the lateral ventricles are relatively rare. The authors have operated on eight cases with trigonal tumors during a 10-year period. Four cases were true intraventricular tumors arising from the ventricular walls, consisting of two meningiomas, one cavernous angioma, and one choroid plexus papilloma. On the other hand, the remaining four cases were paraventricular tumors originating in the adjacent brain and consisted of three astrocytomas and one glioblastoma multiforme. Although these trigonal tumors were readily detected with computed tomographic (CT) scanning, differential diagnosis was difficult because of their similar appearances on CT scans. The initial symptoms were headache in seven, and the neurological examination revealed personality changes, choked disc, visual field defects, hemiparesis, etc., in four, and no deficits in the remaining four cases. All cases were operated on via superior or middle temporal gyrus incision, and the surgical results were good except for one case who died of postoperative brain edema. In the four cases with tumors located in the dominant hemisphere, two were left with sensory aphasia, dyslexia, dyscalculia, and hemianopsia which improved within 6 months. In these two cases, postoperative CT scans revealed cerebrospinal fluid retention with severe edema along the surgical route which disappeared spontaneously within 3 months. We consider that the temporal gyrus incision was the safest approach, even though the tumor was located in the dominant side.

Adolescent↗
PubMed1989

Malignant cerebellar astrocytic tumours in children.

The authors reviewed 5 cases of histopathologically verified malignant cerebellar astrocytic tumours (2 anaplastic astrocytomas and 3 glioblastomas) in children admitted to our department. All cases exhibited symptoms and signs of increased intracranial pressure and of a cerebellar lesion. Brain stem symptoms were present in 4 cases. All of the tumours were located in or near the midline of the cerebellum with no large cyst. Surgical removal (70 to 90% removal) of the tumour was performed in 4 cases. In one case only a biopsy was done. Even with subsequent follow-up treatment including radiotherapy, chemotherapy, and/or immunotherapy, the course of the disease could not be reversed, and all of the children died 3 to 13 months (mean 7 months) after admission due to tumour re-growth or recurrence. Tumour dissemination along the walls of the ventricular system was seen in 2 cases, and was considered to be a peculiar, fatal form of tumour recurrence in patients with this type of tumour. Malignant cerebellar astrocytic tumours in children have an extremely poor prognosis. Until, improved therapy is available to counteract this tragic consequence, it will remain so.

Adolescent↗
PubMed1989

Clinical features and outcome in 68 cases of aneurysmal subarachnoid hemorrhage without aneurysm repair--a community hospital study.

The authors studied the clinical features and outcome at 6 months in 191 patients with subarachnoid hemorrhage (SAH) from ruptured aneurysms. Aneurysm repair (AR) was undertaken in 123 cases (64.4%). In the non-AR group (n = 68), 48.5% of the patients were 70 years of age or older, compared with 12.2% in the AR group. The duration from onset to admission was less than 3 hours in 48 non-AR cases (70.6%) and in 42 AR cases (34.1%). Among non-AR patients, 63.2% were Hunt and Hess grade IV or V, whereas the figure for AR patients was only 14.7%. By 6 months after SAH, 94.1% of non-AR patients had died, and the remainder were vegetative or severely disabled. In contrast, only 15.4% in the AR group died, and over 50% showed good recovery. The large majority of non-AR patients were treated conservatively because they were judged to be poor surgical risks and, among these patients, nearly one half were elderly. In the 10 elderly patients considered good surgical candidates, vasospasm was the most common reason (70%) for not performing AR.

Adult↗
PubMed1989

[Morphological changes in basement membrane associated with endothelial proliferation in astrocytic tumors--an immunohistochemical study of laminin].

Morphological changes of the basement membrane associated with endothelial proliferation in astrocytic tumors are studied in this report. Laminin is known to be a specific glycoprotein of basement membranes. We applied this characteristic of laminin to enable us to observe various characteristics of the basement membrane. The presence of laminin in 13 glioblastomas, 15 anaplastic astrocytomas, 7 astrocytomas, and 6 pilocytic astrocytomas was examined by peroxidase-antiperoxidase (PAP) staining of formalin-fixed and paraffin-embedded surgical specimens. White matter from five normal cerebral hemispheres obtained during autopsy and subsequently embedded using the same method, were used as a control. Laminin was observed at the glioma-mesenchymal junction in astrocytic tumors, and the deposits of laminin made the tumor vasculature come into intense relief. The destructive changes of the basement membrane, including disruption, thickening, disconnection, dissociation, winding, and conjunction, became greater with progressive endothelial proliferation in astrocytic tumors. Those changes were seen to be most remarkable in glioblastoma. In addition, there was a marked variety of morphological change in the basement membrane in different areas of glioblastomas, although the changes were almost constant in other astrocytic tumors. We present a schematic hypothesis of the stages of angiogenesis in glioblastoma based on the above morphological changes of the basement membrane and discuss it in this report.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗