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Biomedical subjects

Takumi Abe

Publications and source records attributed to Takumi Abe.

At least 19 recordsLinked to original sources
PubMed2026

Neutrophil extracellular traps induced by a monoclonal anti-phosphatidylserine/prothrombin antibody activate platelets in vitro.

Antiphospholipid syndrome (APS) is an autoimmune thrombotic disorder characterized by the presence of antiphospholipid antibodies, including anti-phosphatidylserine/prothrombin antibodies (aPS/PT). While neutrophil extracellular traps (NETs) are implicated in the pathogenesis of APS, the role of aPS/PT in NET induction and its contribution to thrombosis remain unclear. This study aimed to clarify the effects of NETs induced by a monoclonal aPS/PT antibody on platelet activation and their potential contribution to thrombo-inflammatory responses. NETs were induced by stimulating peripheral blood neutrophils from healthy donors with aPS/PT. Their morphology and platelet-activating capacity were compared with NETs induced by anti-neutrophil cytoplasmic antibodies (ANCAs). Proteomic analyses were conducted to comprehensively compare protein compositions of these NETs, and candidate proteins associated with platelet activation in aPS/PT-induced NETs were identified. Functional inhibition assays were then conducted to assess whether blocking these candidates would suppress aPS/PT-induced NET-mediated platelet activation. We found that binding of aPS/PT to neutrophils induced NET formation, with a larger and more fibrous morphology compared to ANCA-induced NETs. Platelets trapped in aPS/PT-induced NETs showed significantly higher activation compared to those trapped in ANCA-induced NETs. Proteomic analyses identified histone H3 as a potential mediator of platelet activation in aPS/PT-induced NETs. Correspondingly, plasma concentrations of H3.1 nucleosome were significantly higher in patients with APS than in healthy controls. Blockade of histone H3 using a neutralizing antibody significantly suppressed platelet activation mediated by aPS/PT-induced NETs. These findings suggest that aPS/PT-induced NETs contribute to platelet activation and may promote thrombo-inflammatory responses in APS. Targeting histone H3 within aPS/PT-induced NETs may provide a potential therapeutic strategy for thrombo-inflammatory processes in APS.

Humans↗
PubMed2006

Electromagnetic field system for transsphenoidal surgery on recurrent pituitary lesions - technical note.

BACKGROUND: Post operative scar tissue makes transsphenoidal surgery for recurrent pituitary lesions very difficult. However, with the use of a new cautery system, known as the EMF system, we were able to perform the surgical procedures with relative ease. In this article, we report the advantages and clinical applications of this new instrument in transnasal reoperation. METHODS: The EMF system generates a high frequency current of 13.56 MHz that is focused on the target. This enables it to coagulate, cut, and vaporize tissue in a pinpoint fashion. The bayonet and pencil-type hand pieces of the EMF system are slim, and the tips of the probe are flexible. This enables the surgeon to easily reach deep narrow spaces. We have used the EMF system for transsphenoidal surgery on recurrent pituitary lesions in 18 patients. The system was used to cut and vaporize scar tissue and vaporize firm and fibrotic tumor tissue. RESULTS: During surgery, the system could easily cut and vaporize scarred tissues in the nasal cavity, the sphenoid sinus, and the sella, without damage to the surrounding tissue. In addition, in 3 patients who had extremely fibrotic and firm tumors, we were able to easily vaporize the tumor with safety. CONCLUSIONS: The EMF system enables the surgeon to cut and vaporize tissue with ease and with minimal injury to the surrounding structures. It was particularly valuable in the resection of firm tumors. It may also shorten the operating time because of quick vaporization of the firm tissue.

Adenoma↗
PubMed2006

Transsphenoidal microsurgery for newly diagnosed acromegaly: a personal view after more than 1,000 operations.

The aim of this short review is to inform about the possibilities and limits of transnasal microsurgery in acromegaly. The current reports on surgical remissions, according to the strict criteria with international consensus using age- and sex-related normal levels for insulin-like growth factor-I and suppression of growth hormone (GH) with oral glucose tolerance below 1 mug/l, are more or less agreeable with values between 34 and 74%. In microadenomas (<10 mm in diameter), 59-95% remissions are published. Some improvement might be achieved in macroadenomas which presently have a chance of 26-68% to be satisfactorily operated on. Special instruments introduced by us to visualize and remove partially invasive adenoma parts are described. Intraoperative magnetic resonance imaging is discussed. With intraoperative measurement of GH, small adenoma rests <3 mm can be diagnosed. When GH did not sufficiently decline, an additional tumor search resulted in a significant improvement in results in resectable macroadenomas. With these techniques, we achieved remission rates which can hardly be further increased (micros 95%, macros 68%). In grossly invasive grade 4 adenomas, which are frequent in our unit, only an 80-95% reduction in tumor mass is feasible. Preoperative treatment with somatostatin analogues as used in most of our patients reduces the comorbidity and facilitates adenoma removal which is still controversially discussed in the literature. The complication rate of microsurgery in experienced hands is low.

Acromegaly↗
PubMed2005

Enhancement of cauliflower mosaic virus 35S promoter in insect cells infected with baculovirus.

We happened to discover that the cauliflower mosaic virus (CaMV) 35S promoter inserted into a recombinant Autographa californica multicapsid nucleopolyhedrovirus (rAcMNPV) was strongly activated during the replication of the recombinant virus in Spodoptera frugiperda (Sf9) cells. The expression of the luciferase gene from the 35S promoter in rAcMNPV was remarkably increased late in infection and was resistant to alpha-amanitin treatment. Primer extension indicated that transcriptional initiation from the 35S promoter in Sf9 cells occurred within one of the two baculoviral late promoter TAAG motifs located in the vicinity of the transcription start site in plant cells. These observations suggested that the CaMV 35S promoter served as a transcription start site for AcMNPV-induced RNA polymerase.

Animals↗
PubMed2005

Practical synthesis of Dirhodium(II) tetrakis[N-phthaloyl-(S)-tert-leucinate].

An efficient and reliable procedure for the preparation of dirhodium(II) tetrakis[N-phthaloyl-(S)-tert-leucinate], Rh2(S-PTTL)(4), a universally effective catalyst for a range of enantioselective carbene transformations, is described. The N-phthaloylation of (S)-tert-leucine by the method of Bose with essentially no racemization is a key to this process.

Catalysis↗
PubMed2005

Evaluation of hyperacute stroke using perfusion computed tomography.

Evaluation of the cerebral circulation dynamics in patients with stroke soon after onset is extremely important for planning the optimum treatment. Perfusion computed tomography (CT) was evaluated in 118 patients with stroke within 10 hours of onset in whom initial CT showed no ischemic change. The mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV) perfusion CT maps were visually evaluated in three slices covering the body of the lateral ventricle, the basal ganglia, and the pons, and the ratios of the values in regions of interest (ROIs) in the ischemic lesion and the symmetrical location in the opposite hemisphere were calculated (ROI ratio of regional (r) MTT, rCBF, and rCBV). The location of occlusion was confirmed by angiography performed on the same day in 106 cases and the location of infarction by later magnetic resonance (MR) imaging. MTT maps correctly identified 44 of 46 cases of ischemia in the carotid system, 20 of 29 cases of ischemia in the vertebrobasilar system, and 11 of 35 cases of ischemia in perforator regions. Eight cases could not be identified by perfusion CT, angiography, or MR imaging. The ROI ratios at the upper boundary of infarction (n = 18) were: rCBF 0.574 +/- 0.220 (mean +/- SD) and rCBV 0.972 +/- 0.276, and at the lower boundary of non-infarction (n = 24) were: rCBF 0.504 +/- 0.247 and rCBV 0.815 +/- 0.169; showing a statistical significance of p = 0.348 for CBF and p = 0.026 for CBV (unpaired t-test). The perfusion CT MTT maps correlated well with the angiographical findings for the carotid system, but poorly for the vertebrobasilar system and the perforator regions. A rCBF ratio of 0.5 and rCBV ratio of 0.9 were established for the boundaries of ischemia.

Aged↗
PubMed2005

Three-dimensional computed tomography angiography of the galenic system for the occipital transtentorial approach.

The venous variations of the galenic system were evaluated using three-dimensional computed tomography angiography (3D-CTA) to assess the influence on the occipital transtentorial approach in 150 patients who underwent 3D-CTA as a routine screening examination for cerebrovascular diseases. The variations of the vein of Galen with its tributaries, the tentorial sinus, and the veins around the tentorium were evaluated in multiple intensity projections and stereoscopic images. The angle between the vein of Galen and the straight sinus was 67.1 +/- 31.9 degrees (mean +/- SD). Observation of the pineal body from the direction of the approach tended to extend to the quadrigeminal bodies in acute angle cases, and to the third ventricle in obtuse angle cases. Bilateral internal cerebral veins (ICVs) joined in the anterior portion were associated with a long vein of Galen, or in the posterior portion with a short vein of Galen. The distance between the bilateral ICVs was 4.66 +/- 2.28 mm (mean +/- SD), and the shape of the space could be classified as spindle, parallel, hairpin, and round types. The basal vein could be classified into well-developed, hypoplastic, hardly recognized, and mimicking two basal veins because the tributary did not join but ran parallel to the basal vein. The drainage pathways lead to the anterior or posterior portion of the vein of Galen, the ICV, the tentorial sinus, and the superior petrosal sinus. The various types of the tentorial sinus and primitive tentorial sinus which might be sacrificed during section of the tentorium were confirmed. The inferior cerebral vein draining to the tentorial sinus could be seen. 3D-CTA could also demonstrate the presence, the course, and the drainage points of the internal occipital vein, the precentral cerebellar vein, the posterior pericallosal vein, and so on. 3D-CTA is useful to evaluate the variations of the venous system and the relationship with the tumor, and for preoperative simulation and intraoperative navigation of the occipital transtentorial approach.

Cerebral Angiography↗
PubMed2005

[A case of a hemorrhagic non-functioning pituitary adenoma presenting with abducens nerve palsy].

A pituitary adenoma presenting with isolated abducens nerve palsy is an extremely rare occurrence. The authors report a rare case of a hemorrhagic non-functioning pituitary adenoma presenting with isolated abducens nerve palsy. The etiology of isolated abducens nerve palsy by a pituitary tumor is discussed. A 34-year-old male presented with severe headache, vomiting, right-sided ophthalmic pain, and diplopia. On admission, he had right-sided isolated abducens nerve palsy. Magnetic resonance (MR) images demonstrated a less-enhancing intra-and suprasellar mass lesion with intratumoral hemorrhage and right-sided slight cavernous sinus invasion, that exhibited an iso-high mixed intensity on T1-weighted image and a low-high mixed intensity on T2. Cerebral angiogram revealed no abnormality. The pituitary hormone function was within normal range. The tumor was totally resected via the transnasal route. The histological diagnosis was a typical non-functioning pituitary adenoma with hemorrhage. The abducens nerve palsy was completely resolved 7 months after surgery. It was supposed that the isolated abducens nerve palsy was caused by the direct compression of abducens nerve in the cavernous sinus by the extension of a pituitary tumor and hematoma. Pituitary adenoma should be considered in the differential diagnosis of abducens nerve palsy. Early diagnosis and transsphenoidal surgery is recommended to improve the abducens nerve palsy.

Abducens Nerve Diseases↗
PubMed2005

[A case of cerebellar tuberculoma].

We report a case of cerebellar tuberculoma presenting with headache, without any specific data. A 22-year-old male had headache for recent three months. Because of detection of the tubercle bacillus in his sputum, he was suspected the pulmonary tuberculosis and the tuberculous meningitis. On admission the cerebrospinal fluid revealed no abnormal data and the tubercle bacillus was not detected in the culture. We started medication for the tuberculosis. MRI demonstrated a mass lesion at the right cerebellum, suggesting the presence of a tuberculoma. He underwent total removal of the tumor via the supracerebellar route. Histological examination revealed tuberculoma when there are no abnormal data. The intracranial tuberculoma may be confused with an intracranial neoplasm. It is important to make an overall evaluation to diagnose tuberculosis; for instance, compromised high age, HIV, and the type of steroid administered, will increase intracranial tuberculoma. In this report, we describe a cerebellar tuberculoma without any abnormal data, suggesting that intracranial tuberculoma should be considered in the differential diagnosis of any intracranial mass lesion.

Adult↗
PubMed2004

Clinicopathological examination of glioma by proton magnetic resonance spectroscopy background.

Automation of proton magnetic resonance spectroscopy (MRS) in recent years has made it possible for MRS measurement to be performed in a shorter time than before, and the number of reports of its usefulness for the assessment of glioma malignancy has been increasing in the past several years. We studied the efficacy of proton MRS when used for glioma and conducted clinicopathological examination of glioma. The subjects were 15 patients who had received a pathological diagnosis of glioma at our hospital (6 cases of glioblastoma, 1 case of anaplastic astrocytoma, 4 cases of low-grade astrocytoma, and 4 cases of radiation necrosis); Siemens Magnetom Vision 1.5T was used for the study. Regions of interest (ROIs) were defined as the areas where abnormal signals were found on magnetic resonance imaging (MRI). Areas of primary peaks, such as choline (Cho), N-acetylaspartate (NAA), and lactate (Lac), were measured, and the ratios to normal brain tissue were examined. This study revealed a tendency of increased malignancy of glioma with a decrease in NAA. Some cases also displayed a decrease in Cho with an increase in malignancy. Assessment of malignancy must not be based on a single ROI alone, but several ROIs should be assessed comprehensively. Measurement was difficult when the tumor volume was small. Because diagnosis of very early glioma by MRS seemed difficult, other adjunctive diagnoses may be necessary. Proton MRS is very useful for diagnosis of glioblastoma.

Adult↗
PubMed2004

Preoperative evaluation of the venous system for potential interference in the clipping of cerebral aneurysm.

BACKGROUND: Variations of the venous system affecting the surgical treatment of cerebral aneurysm were evaluated using three-dimensional computed tomography angiography (3D-CTA) to evaluate the essential aspects of preoperative diagnosis. METHODS: This study included 50 patients who underwent clipping of cerebral aneurysm through the pterional and trans-sylvan approaches. The 3D-CTA and operative findings were compared to assess the characteristics of cases in which the veins restrict brain retraction, hinder operative manipulations or require sacrifice because of the position in the operative field. RESULTS: Superficial sylvian veins that restricted brain retraction were identified in 8 cases. The veins entered the cavernous sinus in a relatively high position just below either the sphenoid ridge (superior lateral type) or the anterior clinoid process (superior medial type), and the veins entering at a more medial position were closer to the spatula and tended to be compressed or directly excluded (superior medial type). The inferior medial type did not tend to become tense and so did not restrict brain retraction. The inferior lateral type hardly affected the operative manipulation. The first segment of the basal vein of Rosenthal, the uncal vein entering the cavernous sinus, or the sphenoparietal sinus were located in the operative field in six cases, and affected the manipulation of dissecting arteries, and exposure and clipping of the aneurysm. CONCLUSIONS: 3D-CTA provides essential information for operative planning to protect the venous system during the pterional and trans-sylvian approaches.

Brain↗
PubMed2003

Cellular localization of prolactin-releasing peptide receptors in the human pituitary.

The recently identified prolactin (PRL)-releasing peptide (PrRP) is the first hypothalamic peptide hormone found to operate as a ligand of an orphan receptor that specifically stimulates PRL production from the pituitary gland. However, its other biological functions remain unknown. Using immunohistochemistry, we examined the distribution of the PrRP receptor in various human tissues, as well as the precise localization of the PrRP receptor in the human normal pituitary. Among various tissues examined, PrRP receptor-immunopositive cells were detected only in the pituitary gland. A double immunohistochemical procedure was used to examine PrRP receptor-positive cells from ten normal human pituitary glands, and it was determined that numerous PrRP receptor-positive cells are also positive for adrenocorticotropic hormone (ACTH) but negative for PRL. Growth hormone-, beta-thyroid-stimulating hormone-, beta-follicle-stimulating hormone-, beta-luteinizing hormone- or alpha-subunit-positive cells did not test positive for the presence of PrRP receptors. Thus, we suggest that PrRP receptor and probably PrRP may play a regulatory role in ACTH secretion, rather than in the release of PRL from the human anterior pituitary. This is the first report to demonstrate colocalization of the PrRP receptor and ACTH by immunohistochemistry.

Animals↗
PubMed2003

Gliomatosis cerebri in a young patient showing various cranial nerve manifestations: a case report.

A case of gliomatosis cerebri in a 27-year-old man showing various cranial nerve manifestations is described. He was diagnosed as having cranial mononeuritis multiplex (bilateral oculomotor nerve paralysis, left facial nerve paralysis, bulbar palsy manifestations, and hypoglossal nerve paralysis) and was hospitalized in the neurology department on August 1, 2000. Although he continued to visit the neurology department after discharge, his manifestations showed no improvement. He was sent to our department for brain biopsy in August 2001. A biopsy performed at the Sylvian fissure from the frontal lobe/temporal lobe cortex showed high intensity on T2-weighted and Flair magnetic resonance imaging (MRI). The pathological findings were diffuse low-grade astrocytoma infiltrating between the pia mater and the cerebral cortex. We believed that the astrocytoma spreading on the subpia mater was responsible for the various cranial nerve manifestations, and we started whole-brain irradiation (46 Gy) + interferon (IFN)-beta D.I.V. from September 2001. The pathological findings of the brain biopsy showed diffuse astrocytoma. The clinical presentation was dramatically improved after radiotherapy. It seemed that this tumor had spread along the subpia mater and subependyma. When he was discharged in early December, he walked by himself. The characteristic features of this case are that no lesion in the cerebellum or brain stem was found on MRI, even though the main manifestations were cerebello-brain stem manifestations, and biopsy of the cerebral cortex revealed astrocytoma. It should be noted that the clinical manifestations of astrocytoma in some cases are dissociated from the imaging observations.

Adult↗
PubMed2003

Effectiveness of secondary transnasal surgery in GH-secreting pituitary macroadenomas.

Transsphenoidal surgery is the first therapeutic option in acromegaly, but the management of persistent or recurrent cases of the disease after surgery has been controversial. This study presented the results of secondary transnasal surgery for residual or recurring growth hormone (GH)-secreting macroadenoma with reference to intraoperative GH measurement. It focused on 22 patients who underwent secondary transsphenoidal surgery for 18 residual and 4 recurring GH-secreting pituitary macroadenomas from 1990 to 1999. To assess complete tumor removal, plasma GH concentration was measured intraoperatively. Before secondary surgery, plasma GH levels without medical treatment ranged from 2.0 to 239.0 microg/l (mean 31.5 +/- 50.4). Magnetic resonance imaging demonstrated 16 transnasally resectable tumors and 6 nonresectable grossly invasive tumors. Intraoperative plasma GH concentrations declined sufficiently in 9 of 16 with transnasally resectable tumors, but in the remaining 7 cases the tumors were further explored and normalization of GH levels was ultimately obtained in 4 out of these cases. It was impossible to completely remove the tumors in all the 6 patients with transnasally nonresectable tumors. Thirteen of 22 patients achieved endocrinological remission by rigorous criteria. In transnasally resectable tumors, the endocrinological remission rate was 81.3% (13 of 16 patients) with no recurrence during the follow-up period of at least 4 years. Secondary transnasal surgery for residual or recurring GH-secreting pituitary macroadenomas is a safe and effective treatment, if done along with intraoperative GH measurement. Endocrinological remission can be obtained with high probability in patients who suffer from macroadenomas with suprasellar extension, with the exception of transnasally nonresectable grossly invasive tumors.

Adenoma↗
PubMed2003

Duplex Doppler ultrasonography of subclavian steal syndrome--three case reports.

Three cases of subclavian steal syndrome were detected by duplex Doppler ultrasonography. Ultrasonography demonstrated retrograde flow with to-and-fro pattern in the right vertebral artery in two cases, and reflux with diastolic flow deceleration in one case. Interventional treatment with stenting was successfully performed in two cases and conservative treatment was given in one case. Ultrasonography is an effective noninvasive method for the evaluation of the vertebral artery, and should become a routine part of cerebrovascular examinations.

Aged↗
PubMed2002

Transnasal surgery for prolactin-secreting pituitary adenomas in childhood and adolescence.

BACKGROUND: Prolactin (PRL)-secreting pituitary adenomas (prolactinomas) are rare in childhood and adolescence; there are only a few published series of patients who were surgically treated. We discuss the gender-dependent differences, and the surgical indications and results for 14 patients with prolactinomas under 18 years of age at surgery. METHODS: We reviewed the data for 14 patients (10 girls and 4 boys) treated surgically for prolactinomas between 1980 and 1996. Surgery was chosen because of intolerance and/or resistance to dopamine agonist (DA) in 9 patients, the patient's decision in 3, rhinorrhea in 1, and pituitary apoplexy in 1 during DA therapy. All patients underwent direct transnasal explorations. Since 1988, intraoperative PRL measurements were performed. The follow-up period was at least 6 years. RESULTS: Nine of the 10 girls had primary or secondary amenorrhea, and 3 of the 4 boys had visual field defects. The boys and girls were the same age at the onset of symptoms and had the same preoperative duration of symptoms. Boys had larger, more invasive tumors and higher preoperative and postoperative plasma PRL levels than girls. Two boys demonstrated significant extrasellar extension at the time of diagnosis. Two patients required drilling of the incompletely pneumatized sphenoid sinus to reach the sella. Radical tumor resection was achieved in seven girls and in none of the four boys. In 12 of the 14 patients, normal pituitary function was preserved by transnasal surgery. There was no severe surgical morbidity or mortality. Endocrinological remission by surgery alone was achieved for seven girls, and was achieved in 4 of the 5 patients (80%) with microadenomas. In patients with preoperative mean PRL levels of less than 200 microg/L, the surgical cure rate was 75%. CONCLUSIONS: Prolactinomas in childhood and adolescence differ in their biology in boys and girls. Transnasal surgery is as safe in childhood patients as it is in adult patients, and it may be an effective alternative to long-term medical therapy for selected patients with prolactinomas. Successful surgical outcomes were achieved in patients with microadenomas and preoperative serum PRL levels of less than 200 microg/L.

Adolescent↗