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Biomedical subjects

M Taneda

Publications and source records attributed to M Taneda.

At least 19 recordsLinked to original sources
PubMed2005

Successful treatment of a patient with a 13-year history of post-traumatic rhinorrhea due to malabsorption of cerebrospinal fluid.

Chronic cerebrospinal fluid (CSF) leaks associated with skull base fractures are rare but intractable and patients may be subjected to numerous operations. We present a 30-year-old man with a 13-year history of chronic CSF rhinorrhea following a cranial trauma. Computed tomography (CT) showed a bone defect in the planum sphenoidale. CT cisternography revealed a leak from the defect and CSF malabsorption. The absence of symptoms of CSF malabsorption may be attributable to external leakage of excess CSF. After closing the leak via the extended transsphenoidal approach we placed a ventriculoperitoneal shunt for occult hydrocephalus. We discuss the clinical symptoms of chronic CSF leakage and present therapeutic strategies dictated by the mechanisms underlying the leak.

Adult↗
PubMed2001

Lipopolysaccharide-induced subsensitivity of protease-activated receptor-2 in the mouse salivary glands in vivo.

Protease-activated receptor-2 (PAR-2) acts as a modulator of multiple physiological/pathophysiological functions including salivary exocrine secretion. Given the supersensitivity of endothelial PAR-2 under endotoxaemia, we investigated if endotoxin/lipopolysaccharide (LPS) could alter the sensitivity of PAR-2 in the salivary glands. The in vivo salivation in response to i.v. administration of the PAR-2-activating peptide SLIGRL-NH2, but not of carbachol, gradually decreased 6-20 h after LPS administration in the mice. The LPS-induced hyporeactivity to the PAR-2 agonist was partially reversed by repeated administration of aprotinin, a non-specific protease inhibitor. PAR-2 mRNA levels in the salivary glands, as assessed by the semi-quantitative RT-PCR analysis, remained unchanged following LPS challenge. Our findings indicate that in contrast to the supersensitivity of endothelial PAR-2 as described previously, subsensitivity of PAR-2 in the salivary glands develops during the LPS-induced systemic inflammation, which might involve desensitisation of PAR-2 by endogenous proteases.

Animals↗
PubMed2001

Delayed hemispheric neuronal loss in severely head-injured patients.

Recent experimental studies have revealed that traumatic brain injury as well as ischemic brain injury can cause chronic progressive neuronal damage. In the present study, we demonstrate previously unreported delayed cerebral atrophy on computerized tomography (CT) scans in severely head-injured patients. Seventeen severely head-injured patients who required mild hypothermia to control intracranial hypertension after the failure of conventional therapies were retrospectively analyzed. All 17 patients survived more than 1 year. Delayed neuronal loss (DNL) was observed in only eight of the 17 patients. Eight patients with DNL required longer durations of mild hypothermia to control intracranial hypertension than nine patients without DNL. Six of these eight patients with DNL achieved functional recovery despite progressive atrophic changes demonstrated on CT scans. On CT scans, DNL was characterized by (1) the sudden appearance at several months postinjury of a low-density area in the hemisphere ipsilateral to the injury; (2) the preservation of essential cortical structure although related white matter structures showed severe atrophic changes; and (3) no spread of the low-density area to the contiguous territory of the other main cerebral artery. It is concluded that focal primary injury to underlying brain, if severe enough, can result in delayed hemispheric atrophy.

Adolescent↗
PubMed2001

A multicenter prospective randomized controlled trial of the efficacy of mild hypothermia for severely head injured patients with low intracranial pressure. Mild Hypothermia Study Group in Japan.

OBJECT: The criteria for the use of mild hypothermia (34 degrees C) in severely head injured patients have not been standardized. A prospective randomized controlled trial was conducted to determine whether mild hypothermia is essential in the treatment of severely head injured patients with low intracranial pressure (ICP). METHODS: At 11 medical centers, 91 severely head injured patients with an admission Glasgow Coma Scale score of 8 or less in whom ICP could be maintained below 25 mm Hg by conventional therapies were divided randomly into two groups: the mild hypothermia group (HT group, 45 patients) and the normothermia group (NT group, 46 patients). Patients in the HT group were exposed to mild hypothermia (34 degrees C) for 48 hours, followed by rewarming at 1 degrees C per day for 3 days, whereas patients in the NT group were exposed to normothermia (37 degrees C) for 5 days. The two groups were similar with respect to prognostic factors, and there was no difference in clinical outcome at 3 months postinjury. During treatment, there was a significantly greater use of neuromuscular blocking agents in the HT group (p = 0.011). During the initial 2 weeks postinjury, the incidences of pneumonia, meningitis, leukocytopenia, thrombocytopenia, hypernatremia, hypokalemia, and hyperamylasemia were significantly higher in the HT than in the NT group (p < 0.05). CONCLUSIONS: Mild hypothermia should not be used for the treatment of severely head injured patients with low ICP because this therapy conveys no advantage over normothermia in such patients.

Adolescent↗
PubMed2001

Extended transsphenoidal approach with submucosal posterior ethmoidectomy for parasellar tumors. Technical note.

The authors have developed an extended transsphenoidal approach with submucosal posterior ethmoidectomy for resection of tumors located in the cavernous sinus or the suprasellar region that are difficult to remove via the conventional transsphenoidal approach. Surgery was performed using this approach in 14 patients with large pituitary adenomas, three patients with craniopharyngiomas, and one patient with a meningioma of the tuberculum sellae. The submucosal dissection of the nasal septum used in the conventional transsphenoidal approach was extended to the superior lateral wall of the nasal cavity to expose the bony surface of the superior turbinate lying under the nasal mucosa. Submucosal posterior ethmoidectomy widened the area visualized through the conventional transsphenoidal approach both superiorly and laterally. This provided a safer and less invasive access to lesions in the cavernous sinus or the suprasellar region through the sphenoid sinus. Using this approach the authors encountered no postoperative complications, such as olfactory disturbance, cranial nerve palsy, or arterial injury. In this article the authors present the surgical methods used in this approach.

Adenoma↗
PubMed2001

[Dissecting aneurysm of the anterior cerebral artery with later development of collateral circulation: a case report].

Intracranial dissecting aneurysm (DA) is much less frequent than berry aneurysm. Such dissection involves mostly the vertebral and basilar arteries, followed by the internal carotid and middle cerebral arteries. DA of the anterior cerebral artery (ACA) is relatively rare and little is known about its natural Development. Only 23 cases have been reported previously. Our present patient, a 44-year-old man, suddenly developed paresis of the left leg while bathing. Diffusion magnetic resonance imaging indicated an area of high signal intensity in the territory of the ACA. Angiography on day 3 following onset showed a DA involving the left A2 segment. Antiplatelet therapy was administered. Further luminal narrowing in the lesion was demonstrated by repeat angiography on day 17. Occlusion of the distal A2 segment was demonstrated together with sufficient collateral supply on day 41. Symptoms resolved completely. DA of the ACA usually presents with ischemic attacks. Its etiology remains uncertain, and its natural course is unclear. Surgical intervention is recommended for patients with intracranial hemorrhage, while non surgical therapies have achieved good outcomes in ischemic cases.

Adult↗
PubMed2000

Roles of urokinase type plasminogen activator in a brain stab wound.

Urokinase type plasminogen activator (uPA) may influence brain pathophysiology after injury. We studied disruption of the blood-brain barrier (BBB) and changes in the vasculature after a brain stab wound in uPA-deficient, uPA receptor-deficient, and PA inhibitor-1 (PAI-1) deficient mice. The extravasation of immunoglobulin was greater in PAI-1 deficient mice; less pronounced in uPA-deficient mice; similar to controls in uPA receptor-deficient mice. Vasculatures in the wound proliferated in PAI-1 deficient mice. Our study shows that uPA affects BBB disruption. PA enhances angiogenesis after brain injury.

Animals↗
PubMed2000

Difference in nature of ruptured and unruptured cerebral aneurysms.

Although small aneurysms have an extremely low probability of rupture, most aneurysms that rupture are found to be less than 10 mm in diameter. Histological study of aneurysms and epidemiological analysis of subarachnoid haemorrhage revealed that ruptured and unruptured aneurysms are of a different nature.

Aneurysm, Ruptured↗
PubMed2000

Successful treatment of large malignant tumor involving the skull base by radiosurgery combined with intraarterial chemotherapy and embolization.

Stereotactic radiosurgery can be used to treat malignant tumors involving the skull base. While it avoids extensive sacrifice of the normal structures surrounding the tumor, radiosurgery does not eradicate the tumor mass immediately. We present a patient with a large hypervascular malignant tumor involving the skull base that resulted in intracranial hypertension. He was successfully treated with stereotactic radiosurgery combined with intra-arterial chemotherapy and embolization of the arteries feeding the tumor. We discuss radiosurgery, chemotherapy, embolization and other therapeutic modalities for treating large malignant tumors involving the skull base.

Aged↗
PubMed1999

Nigral degeneration following striato-pallidal lesion in tissue type plasminogen activator deficient mice.

Tissue type plasminogen activator (tPA) has been suggested as a key factor in excitotoxic neuronal death in the hippocampus. Transneuronal degeneration of the substantia nigra pars reticulata (SNR) neurons after striato-pallidal lesions is attributable to excess excitatory glutamatergic inputs into the SNR following inhibitory GABAergic deafferentation and tPA may contribute to the mechanism of transneuronal degeneration of the SNR. To examine this possibility, we studied pathological changes in the SNR following striato-pallidal lesions produced by electrocoagulation in tPA-deficient mice. There was no difference in the degree of SNR degeneration, or in microglial activation and proliferation in the degenerating SNR of tPA-deficient and control mice. Our results indicate that tPA does not contribute to transneuronal degeneration in the SNR following striato-pallidal lesions in mice.

Animals↗
PubMed1999

Enhancement of vascular permeability by specific activation of protease-activated receptor-1 in rat hindpaw: a protective role of endogenous and exogenous nitric oxide.

1. To clarify the role of the first thrombin receptor/protease-activated receptor (PAR)-1 in an inflammatory process, we tested and characterized the effect of intraplantar (i.pl.) administration of the highly specific PAR-1 agonist TFLLR-NH2 in rat hindpaw. 2. TFLLR-NH2 administered i.pl. at 0.01-0.03 micromol per paw enhanced vascular permeability in the hindpaw and produced paw oedema in a dose-dependent manner. This effect was almost completely abolished by repeated pretreatment with compound 48/80 to deplete inflammatory mediators in mast cells. 3. The NO synthase inhibitor N(G)-nitro-L-arginine methyl ester or N-iminoethyl-L-ornithine, preadministered i.pl., stereospecifically potentiated the i.pl. TFLLR-NH2-induced permeability increase, while the NO donor sodium nitroprusside or NOC-18, given i.pl., suppressed the effect of TFLLR-NH2. 4. These findings demonstrate that specific activation of PAR-1 produces increased vascular permeability accompanied by oedema formation in the rat hindpaw, predominantly via mast cell degranulation, and that endogenous and exogenous NO plays a protective role in the PAR-1-mediated inflammatory event.

Animals↗
PubMed1999

Multilevel vertebral body replacement with a titanium mesh spacer for aneurysmal bone cyst: technical note.

A 64-year-old male presented with abrupt tetraparesis caused by a minor impact. Diagnostic images obtained on admission showed an aneurysmal bone cyst visible in the cervical spine at the fourth to upper sixth level, although the patient had been wearing a halo brace to diminish the symptoms. The vertebral body from the fourth to the sixth level was dissected, and this space was packed with a titanium cage filled with ceramic bone fragments mixed with fibrin glue. The combination of a titanium cage and an anterior locking plate can be made easily for anterior spinal fusion with enough rigidity to maintain the necessary space during fusion without any major support equipment. Both edges of the titanium mesh cage cut into the vertebral body to hold the cage in place. The other part, the titanium plate, makes it secure until ceramic bone fragments in the cage promote bony ingrowth for fusion.

Bone Cements↗
PubMed1999

Structural fragility and inflammatory response of ruptured cerebral aneurysms. A comparative study between ruptured and unruptured cerebral aneurysms.

BACKGROUND AND PURPOSE: Despite technical advances in endovascular and microsurgical treatment, patients with aneurysmal subarachnoid hemorrhage still have a high mortality and morbidity rate. To improve the treatment results in patients with aneurysms, we must better understand the pathophysiology of cerebral aneurysms and the mechanisms leading to their rupture. Therefore, we studied the pathological differences between unruptured and ruptured aneurysms. METHODS: Ruptured (n=44) and unruptured (n=27) aneurysms were obtained at surgery. The aneurysmal endothelium was scored from 0 (normal) to 5 (complete disruption) by using a scanning electron microscope. The aneurysmal wall was evaluated by immunohistochemical methods. The wall structure was scored from 1 (dense collagen and rich, smooth muscle cells) to 5 (hyaline-like structure). The degree of inflammatory cell invasion into the wall was also scored from 0 (very few cells) to 3 (many cells). RESULTS: Ruptured aneurysms manifested significant endothelial damage (score of 3.7 versus 0.8; Mann-Whitney U test, P<10(-3)), significant structural changes of the wall (3.7 versus 1.7, P<10(-5)), and significant inflammatory cell invasion (2.2 versus 0.8, P<10(-4)) compared with unruptured aneurysms. There was a significant correlation between the score for wall structure and the score for inflammatory cell invasion (Rs=0. 63; Spearman rank correlation test, P<10(-5)). The pathophysiology of several symptomatic unruptured aneurysms was similar to that of ruptured aneurysms. CONCLUSIONS: We conclude that the pathophysiology of unruptured, asymptomatic and ruptured aneurysms is different. The wall of ruptured aneurysms was found to be fragile, possibly because macrophage infiltration into the aneurysmal wall resulted in loss of smooth muscle cells and in degradation of matrix proteins.

Aneurysm, Ruptured↗
PubMed1999

[Examination of the stability of chloral hydrate and its preparation by capillary electrophoresis].

Stabilities of chloral hydrate in an aqueous solution and its medicated syrup were examined by high performance capillary electrophoresis. Analysis of the concentration of chloral hydrate indicated that there was no obvious change in the concentration of chloral hydrate both in the aqueous solution and in the syrup preparation after keeping them for 3 months at room temperature or at 60 degrees C. The lowering of pH was more obvious in the syrup solution than in the aqueous solution, and this tendency was estimated to be due to the formation of hydrochloric acid. We propose that the stabilities of the preparation of chloral hydrate should be monitored by observing pH changes.

Chloral Hydrate↗
PubMed1999

How should a subarachnoid hemorrhage grading scale be determined? A combinatorial approach based solely on the Glasgow Coma Scale.

OBJECT: The purpose of this study was to present a combinatorial approach used to develop a subarachnoid hemorrhage (SAH) grading scale based on the patient's preoperative Glasgow Coma Scale (GCS) score. METHODS: There are 4094 different combinations that can be used to compress the 13 scores of the GCS into two to 12 grades. Break points, the positions in the scale in which two adjacent scores connote a significantly different outcome, are obtained by a direct comparison of the GCS and the Glasgow Outcome Scale (GOS). Guided by the break points, the number of combinations to be considered can be limited. All possible combinations are statistically analyzed with respect to intergrade differences in outcome. Single combinations, with the maximum number of grades having maximum intergrade outcome differences for each corresponding set of adjacent grades, must be selected. The authors verified the validity of this combinatorial approach by retrospectively analyzing 1398 consecutive patients with aneurysmal SAH who underwent surgery within 7 days of the last hemorrhage episode. The patients' GCS scores were assessed just before surgery and their GOS scores were estimated 6 months post-SAH. The combinatorial approach yields only one acceptable grading scale: I (GCS Score 15); II (GCS Scores 11-14); III (GCS Scores 8-10); IV (GCS Scores 4-7); and V (GCS Score 3). CONCLUSIONS: The combinatorial approach, guided by the break points, is so simple and systematic that it can be used again in the future when revision of the grading scale becomes necessary after development of new and effective treatment modalities that improve patients' overall outcome.

Age Factors↗
PubMed1999

Little benefit from mild hypothermia therapy for severely head injured patients with low intracranial pressure.

OBJECT: This study was performed to determine whether mild hypothermia therapy is essential for the treatment of severely head injured patients in whom intracranial pressure (ICP) can be maintained below 20 mm Hg by using conventional therapies. METHODS: Sixteen consecutive severely head injured patients fulfilled the following criteria: the patient's ICP was maintained below 20 mm Hg by using fluid restriction, hyperventilation, and high-dose barbiturate therapy; and the patient had a Glasgow Coma Scale score of 8 or less on admission. After conventional therapies had been applied, the patients were divided randomly into two groups: the mild hypothermia group (HT group; eight patients) and the normothermia group (NT group; eight patients). The HT group received mild hypothermia (intracranial temperature 34 degrees C) therapy for 48 hours followed by rewarming at 1 degree C per day for 3 days, whereas the NT group received normothermia (intracranial temperature 37 degrees C) therapy for 5 days. Specimens of cerebrospinal fluid (CSF) taken from an intraventricular catheter every 24 hours were analyzed for the presence of excitatory amino acids ([EAAs] glutamate, aspartate, and glycine) and cytokines (tumor necrosis factor-alpha, interleukin [IL]-1beta, IL-6, IL-8, and IL-10). The two groups did not differ significantly in patient age, neurological status, or level of ICP. There were no significant differences in daily changes in CSF concentrations of EAAs and cytokines between the two groups. The incidence of pneumonia was slightly higher in the HT group compared with the NT group (p = 0.059). The incidence of diabetes insipidus associated with hypernatremia was significantly higher in the HT group compared with that in the NT group (p < 0.01). The two groups did not differ with respect to their clinical outcomes. CONCLUSIONS: The authors recommend normothermia therapy for the treatment of severely head injured patients in whom ICP can be maintained at lower than 20 mm Hg by using conventional therapies, because mild hypothermia therapy does not convey any advantage over normothermia therapy in such patients.

Adolescent↗
PubMed1999

[Four cases of abducens palsy caused by a vascular lesion of the vertebrobasilar system].

Several pathological conditions are responsible for abducens palsy, but a lesion of the vertebral artery (VA) has rarely been recognized as one of the causes. It has been reported that a high percentage of cases of abducens palsy are involved with ruptured dissecting aneurysms of the VA. We investigate the vertebrobasilar anatomy in 4 patients, suffering with abducens palsy. One patient revealed a fusiform dilatation of the vertebral artery on the same side as the abducens palsy. Three patients were noted to have stenosis of the vertebral artery from the origin of the posterior inferior cerebellar artery (PICA) to the union. Finally, four patients were found to have abnormal vertebrobasilar anatomy, which was on the same side as the abducens palsy. It is conceivable that changes of vertebrobasilar circulation may cause abducens palsy through direct compression, or ischemic events.

Abducens Nerve↗