Biomedical subjects

T Yamaki

Publications and source records attributed to T Yamaki.

At least 73 records · Page 4Linked to original sources

PubMed1995

Kissing aneurysms of distal anterior cerebral arteries demonstrated by magnetic resonance angiography.

BACKGROUND Multiple aneurysms, associated with distal anterior cerebral artery (ACA) aneurysm, are not rare; therefore, it is important to examine multiplicity of the aneurysms preoperatively. CASE REPORT A case of ruptured distal ACA aneurysm, associated with another one in a mirror position, is reported. A 43-year-old woman suffered subarachnoid hemorrhage. Conventional angiography demonstrated a saccular aneurysm on the bifurcation of the right or left distal ACA; however, magnetic resonance angiography (MRA) revealed two mirror-image aneurysms on both bifurcations. CONCLUSION MRA was useful for preoperative diagnosis of kissing aneurysms on distal ACAs.

Adult↗

PubMed1995

Interleukin 4 enhances ganglioside GD3 expression on the human fibroblast cell line WI-38.

Human fibroblast cell line WI-38 cultured in vitro was treated with a human recombinant IL-4 at concentrations of 1 to 100 U/ml to examine the alteration of glycosphingolipid (GSL) expression of the cells. Neutral GSL of non-treated WI-38 cells consisted of CMH (GlcCer), CDH, CTH, and Gb4Cer; CMH and CTH were the major components. The acidic GSL were composed of GM3 as the predominant component and other minor gangliosides including GD3. The neutral GSLs did not change in profile during the treatment with IL-4, while the acidic GSLs showed a prominent change, an increase of GD3 content. The increase of GD3 was detectable with IL-4 concentrations over 1 U/ml, and reached a plateau at 10 U/ml, where the amount of GD3 was almost equal to that of GM3. The GD3 increase occurred at 24 h after the IL-4 treatment, and lasted for at least 96 h, as long as IL-4 remained present in the culture media. The GD3 synthase (sialyltransferase) level was found to be increased in an IL-4 dose-dependent manner. IL-4 did not influence the growth or morphological appearance of WI-38 cells. The results demonstrate a novel biological effect of IL-4, modulating GSL in non-hematopoietic cells.

Cell Line↗

PubMed1995

Disappearance of arachnoid cysts after head injury.

The mechanism of the disappearance of arachnoid cysts is not fully understood. This article discusses the spontaneous disappearance of these cysts after head injury. Five patients underwent computed tomography and were diagnosed as having a subdural hematoma or effusion associated with arachnoid cysts. In four of the five patients, the cyst decreased in size or disappeared. These cases suggest a possible mechanism by which this type of cyst associated with subdural hematoma or effusion might disappear. For the arachnoid cyst to disappear, the rupture of the cyst wall appears to be essential, and after rupture, subdural effusion must develop around the cyst. As this effusion is absorbed, the fluid in the cyst drains away, after which the cyst becomes smaller and gradually disappears. This hypothesis supports the possibility of a "natural cure" for arachnoid cysts without surgical intervention.

Adolescent↗

PubMed1995

[Alexia-agraphia of kanji (Japanese morphogram) after left posterior-inferior temporal lesion].

Several cases of selective alexia with agraphia of kanji have been reported in Japan in this decade. It is well known that the lesion in the posterior inferior temporal lobe of the dominant hemisphere is responsible for this cognitive syndrome. Neuropsychological data in our patient suggest that the postero-inferior region of the temporal lobe of the dominant hemisphere may be the visuo-verbal association area for the analysis of the complex visuo-verbal information. The symptoms caused by the same lesion in western patients might be subangular alexia (alexia without agraphia). Alexia with agraphia of kanji and subangular alexia would appear to be distinct entities, but a dual processing hypothesis of visuo-verbal information and the concept of the visuo-verbal association area might well explain both syndromes.

Agraphia↗

PubMed1995

[A case of subarachnoid hemorrhage with acute subdural hematoma due to head injury: a case report].

Acute intracranial hemorrhages can be caused by cerebrovascular disease or head injury. Diagnostic imaging is in both cases sometimes similar, so it is difficult to make an exact diagnosis. We report a case of acute subdural hematoma due to head injury after loss of consciousness due to an aneurysmal rupture. A 52-year-old male was found out fallen on the floor in a state of unconsciousness and was brought to the nearest hospital. CT scan showed subarachnoid hemorrhage with left acute subdural hematoma and he was transported to our hospital. Angiography revealed a left MCA aneurysm. The next day, a clipping operation was performed but brain contusion was observed in the left frontal lobe. Postoperative CT scan showed contusional hematoma at the left frontal lobe and plain skull X-ray films demonstrated a diastatic fracture of the right lambdoid suture. Acute subdural hematoma due to the rupture of a cerebral aneurysm is sometimes recognized, but the first CT findings are similar to those observed after head injury. When the clinical course of onset is unclear, we must keep in mind that the cause of acute subdural hematoma may be head injury, even if angiography demonstrates abnormal vessels.

Acute Disease↗

PubMed1995

["Disproportionately large, communicating fourth ventricle" due to membranous obstruction of Magendie's foramen].

A case of disproportionately large, communicating fourth ventricle (DLCFV) with the entire ventricular system dilated symmetrically due to membranous obstruction of Magendie's foramen is reported. A 20-year-old female complained of headache and nausea. Slight papilledema was found in both eyes. CT scan and MRI showed that the entire ventricular system was dilated symmetrically, but we could not locate the cause of this disease, for example, tumor, arachnoid cyst, cerebellar malformation and so on. Although cinemode-MRI showed CSF pulsation as if CSF flowed through Magendie's foramen, we were not convinced that CSF flowed through it. We speculated that something obstructed CSF flow at Magendie's or Luschka's foramen, so surgery was performed by suboccipital craniectomy. As expected, a membranous obstruction was found at Magendie's foramen. After excision of the membrane, all symptoms improved. Postoperative cinemode-MRI clearly demonstrated CSF flow through Magendie's foramen. Ventriculoperitoneal shunting is generally effective for DLCFV, but we do not consider it the optimal treatment. The cause of DLCFV must be confirmed by suboccipital craniectomy if evidence of NPH, mass lesion or cerebellar malformation cannot be found anywhere especially around Magendie's foramen.

Adult↗

PubMed1995

Neoplastic endocrine cells in prostatic carcinoma: a case report with immunocytochemical and electron microscopic findings.

A case of a 68-year-old male with prostatic carcinoma which was partially well differentiated but largely poorly differentiated is presented in this report. The poorly differentiated area of the adenocarcinoma seemed to arise from the well-differentiated portion. The former was populated with Grimelius argyrophilic cells, and occasionally contained round, eosinophilic intracytoplasmic inclusions which appeared to be composed of a secretory substance. Immunocytochemistry revealed that endocrine cells were present in the normal portion of the gland as well as in the well-differentiated adenocarcinoma, but were more numerous in the poorly differentiated portion. The latter portion was positive for chromogranin A, endocrine granule constituents, neuroendocrine markers, serotonin, Leu 7, ACTH and neuron specific enolase. In addition, cells of poorly differentiated portion were reactive with CEA, prostatic acid phosphatase and human prostate specific antigen. Ultrastructural features observed in the poorly differentiated adenocarcinoma included five kinds of round neurosecretory granules. This was a rare case of prostatic adenocarcinoma in which the evolution from well differentiated to poorly differentiated tissue containing neuroendocrine constituents could be clearly observed.

Adenocarcinoma↗

PubMed1994

Attenuation of the neurotoxic effect of A beta amyloid peptide by apolipoprotein E.

Alzheimer's disease patients have increased frequency of apolipoprotein E allele c4, suggesting apoE4 is a risk factor determining disease. ApoE binds A beta amyloid peptide with great avidity in vitro and in the neuritic plaque. Potentially, binding of A beta to apolipoprotein E could increase A beta neurotoxicity. However, in hippocampal cultures, 0.1 microM apolipoprotein E eliminated the neurotoxicity of 10 microM A beta. Neuronal rescue was dose-dependent and occurred even after 48 hours exposure to A beta, but was overwhelmed by excess A beta. Thus, interaction between these proteins does not directly increase A beta neurotoxicity, and the role of ApoE in Alzheimer's disease remains to be elucidated.

Amyloid beta-Peptides↗

PubMed1994

Frequent expression of 75 kDa nerve growth factor receptor and phosphotyrosine in human peripheral nerve tumours: an immunohistochemical study on paraffin-embedded tissues.

One hundred and three benign, and 10 malignant peripheral nerve tumours were examined immunohistochemically for expression of 75 kDa nerve growth factor receptor (NGFR). In benign tumours NGFR was demonstrated at 61% in neurinoma, 71% in neurofibroma, 93% in neurofibromatosis and 90% in traumatic neuroma. Malignant neurogenic tumours were 100% positive for NGFR. Phosphotyrosine-immunoreactivity was detected in 76% of NGFR-positive tumours but the frequency of immunostained tumour cells was low. These results suggest that both benign and malignant peripheral nerve tumours express 75 kDa NGFR. The receptor seems to serve as growth signal transduction of the tumour cells in terms of phosphorylation of the tyrosine residue of the receptor or the target protein of the NGFR protein tyrosine kinase.

Humans↗

PubMed1994

Basic fibroblast growth factor messenger RNA is expressed strongly at the acute stage of cerebral contusion.

Basic fibroblast growth factor (bFGF) has a neurotrophic effect both in vitro and in vivo, and is considered to play an important role in the maintenance of neuronal functions in the normal brain. Neural damage in brain contusion progresses after the primary injury of trauma because of cerebral hemodynamic and metabolic impairment including intracranial hemorrhage and/or brain swelling. Northern blot analysis of bFGF mRNA was performed in rats after cerebral contusion produced by our modified fluid percussion device. Expression of bFGF mRNA increased significantly on the second day after trauma. A possible role of bFGF is functioning to protect the critical neurons from secondary neural damage in cerebral contusion.

Actins↗

PubMed1994

A modified fluid percussion device.

This report examines a modified fluid percussion device with specific improvements made to address deficiencies found in previously reported devices. These improvements include the use of a cylindrical saline reservoir made of stainless steel, placement of the reservoir in a 15-degree head-up position for the easy release of air bubbles, placement of the fluid flushing outlet and the pressure transducer close to the piston on the same plane, with both perpendicular to the direction of the piston, and adjustable reservoir volume to vary the waveform of the pressure pulse, and a metallic central injury screw secured to the animal's skull over the exposed dura. Using this device, midline fluid percussion (MFP) and lateral fluid percussion (LFP) injuries were performed in 70 rats. Histopathologic findings included diffuse axonal injury in the MFP model and cortical contusion in the LFP model. Survival rate was 41.4% in MFP animals and 100% in LFM animals when the device settings were 178 mm3 of the cylindrical reservoir and 50 degrees-60 degrees in height of the pendulum. Our results suggest that this modified fluid percussion device may offer significant improvements over previously reported fluid percussion models for use in experimental head injury.

Animals↗

PubMed1994

[An experimental study of the efficacy of platelet aggregating inhibitor on hepatic metastasis].

To investigate whether OKY-046 (an inhibitor of thromboxane A2 synthetase) and TCV-309 (an antagonist of platelet activating factor) can inhibit VX-2 tumor metastasis, the following studies were performed. Study 1 animal experiment: VX-2 tumors were inoculated and OKY-046 or TCV-309 was administered into the portal vein with or without combination of adriamycin (ADR). The number of tumor nodules on the whole liver surface were counted at three weeks after tumor cells inoculation. The combination of OKY-046 and ADR significantly reduced the number of tumor nodules compared to control and TCV-309. Study 2 in vitro experiment: Human breast cancer cells (MCF-7) overlayed confluently cultured human endothelial cells (HUVEC) in vitro with or without OKY-046 and TCV-309 for 3 days; MCF-7 cells invaded the endothelial cells and built-up colonies. The number of colonies built up were counted. OKY-046 significantly decreased the number of colony formations, but TCV-309 did not. These results suggest that OKY-046 has an inhibitory effect on extravasation of tumor cells.

Animals↗

PubMed1994

[Percutaneous transluminal angioplasty for progressing stroke caused by severe basilar artery stenosis: case report].

We encountered one case of progressing stroke caused by severe basilar artery stenosis. The patient was treated with emergent percutaneous transluminal angioplasty (PTA) with satisfactory results. A 54 year-old woman was admitted 15 minutes after the sudden onset of rt. hemiparesis, rt. hemidysesthesia, dysarthria and consciousness disturbance. CT scan on admission showed no abnormal findings. The consciousness level of the patient deteriorated rapidly from JCS 1 to JCS 20 within 30 minutes from the ictus. An emergent angiogram revealed severe basilar artery stenosis at its middle portion and poorly developed collateral circulation. One hour after the stroke occurred, PTA was performed. Using a 3mm diameter balloon catheter, we introduced the balloon into the stenotic lesion and inflated it 6 times from 4 atm to 8 atm pressure. The patient recovered immediately on the operating table improving from JCS 20 to JCS 1. Rt. hemiparesis also improved. Follow-up MRI showed a small area of ischemic change in the brain stem, but no large infarction appeared. The patient was discharged with no neurosurgical deficits after 30 days of PTA. PTA for basilar artery stenosis is still a controversial subject. One reason is the risk of basilar artery perforating branches occlusion by balloon catheter and the other is the difficulty of introducing a flexible balloon catheter into the basilar artery beyond the acute angulation of the vertebral artery. If those two problems were solved, PTA would be the first-choice therapy for basilar artery stenosis in both acute and chronic stages.

Acute Disease↗

PubMed1994

[Cerebellar infarcts that require differentiation from tumors: diagnosis with MRI].

It is often difficult to differentiate cerebellar infarct with cerebellar swelling from neoplastic disorders, because former can be shown as cerebellar mass with marked contrast enhancement on CT scan. We analyzed radiologically three cases with cerebellar infarction by using MRI, conventional CT scan and angiography. Two cases in the acute stage could be diagnosed as cerebellar infarction by MRI alone based on the following findings: 1) the lesion was distributed in the territory of cerebellar arteries; 2) the normal pattern of cerebellar folia and fissures was preserved in Gd enhancement MRI image; 3) characteristics of MRI intensity were compatible with hemorrhagic infarction. The other case in the chronic stage showed peculiar enhancement, which was unusual for infarction. It was diagnosed as cellular infarction with reference to the angiographic findings. MRI is generally useful to obtain early diagnosis of tumor-like cerebellar infarcts, and proper treatment should be started as early as possible.

Aged↗

PubMed1993

Human blood group B-active ganglio-glycosphingolipid in rat glioma.

A human blood group B-active glycosphingolipid, belonging to the ganglio-series, was isolated from rat glioma cell line RG2 subcutaneous isografts. The oligosaccharide structure of the glycosphingolipid was completely characterized as Gal alpha 1-3(Fuc alpha 1-2)Gal beta 1-3GalNAc beta 1-4Gal beta 1-4Glc beta 1- 1'ceramide by NMR spectrometry, negative fast atom bombardment-mass spectrometry, sequential degradation by glycosidases and methylation analysis. Human blood group B antigenicity and the activity of this glycosphingolipid were confirmed by immunostaining on thin-layer chromatography and the inhibition of hemagglutination, respectively. Although the lipid has been detected in rat granuloma, bone marrow cells, spleen, thymus, ascites hepatoma cells and gastric mucosa, this is the first report of the occurrence of the B-active lipid in glioma.

ABO Blood-Group System↗

PubMed1993

Effect of local administration of lymphokine-activated killer cells and interleukin-2 on malignant brain tumor patients.

Nine patients with malignant brain tumors were treated with intratumoral infusion of lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2). LAK cells were generated from macrophage-depleted peripheral blood lymphocytes by culturing with IL-2 for 4 days. The resulting LAK cells showed strong cytotoxic activity against tumor target cells. Three patients received sufficient LAK cells (> or = 5.76 x 10(8)) to show partial tumor response by computed tomography and clinical signs. No severe neurological side effects occurred in any patient. Intratumoral administration of LAK cells and IL-2 can be effective in patients with malignant brain tumors.

Adult↗

PubMed1992

Evaluation of cytocentrifuge apparatus with special reference to the cellular recovery rate.

Two types of commercially available cytocentrifuge apparatus (type A and type B apparatus) using disposable funnels were compared for percentage of cell recovery and degree of cell preservation. The cellularity of each cell suspension was determined using a Sysmex micro cell counter for blood analysis, and the cell recovery was obtained by counting cells in the total smeared area on the May-Grünwald Giemsa (MGG)-stained slide. Overall recovery rate by the type A apparatus was between 54.3% and 74.9% with a mean of 63.0%, whereas, the recovery rate for type B apparatus was between 30.6% and 51.8%, with a mean of 42.5%, indicating that the type A apparatus was significantly better. In the type A apparatus, a higher yield of all cells was obtained (69.7-74.9%) in the group of low cell counts (350 cells/0.5 ml), which was run for 10 minutes at 2,000 rpm. On the other hand, in the type B apparatus a higher yield of all cells was obtained (38.6-42.6%) in the group of low cell counts which was run for 10 minutes at 2,000 rpm. Cellular structure was better preserved on the slides in the type A apparatus. However, the percentage of ghost cells was somewhat higher in the type B apparatus. The cytocentrifugation of the type A apparatus consistently recovered a higher percentage of cells than with the type B apparatus. Using the type A apparatus, a high rate of cellular recovery, which is extremely important, such as for accurate morphological evaluation of cerebrospinal fluid, can be consistently obtained.

Centrifugation↗

PubMed1992

Results of reoperation for failed microvascular decompression.

Among 64 patients with hemifacial spasm (HFS) and 60 with trigeminal neuralgia (TN) treated by microvascular decompression (MVD), repeated MVD performed on 3 cases with HFS resulted in the absence of spasm in all cases. In 7 cases with TN, this technique resulted in complete remission in 2, recurrence in 3, and no pain relief in 2 cases. MVD was more effective on HFS than on TN in repeated procedures as well as for initial treatment. The cause of recurrence of HFS was attributed to the inadequate cushion effect of muscle as a prosthesis, while that for TN was suspected to be related more to post-operative fibrotic adhesions formed around the fifth nerve.

Adult↗