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Biomedical subjects

T Tsubokawa

Publications and source records attributed to T Tsubokawa.

At least 55 records · Page 3Linked to original sources
PubMed1994

Magnetic resonance angiography in the management of childhood moyamoya disease: first choice for neurovascular scrutiny.

We performed magnetic resonance angiography (MRA) in 12 children with a suspected or angiographically proven moyamoya disease. MRA was performed by the three-dimensional, time-of-flight technique and, successfully depicted the primary abnormalities in the distal carotid arteries in 10 out of the 12 patients. In the other two patients, poor visualization of the intracranial vasculature strongly suggested the presence of the disease. On MRA, moyamoya vessels were visible in eight patients. The presence of anastomoses was also confirmed by MRA in seven of the 10 patients who had undergone encephalo-duro-arterio-synangiosis. Our findings suggest that MRA may be the tool of choice for selecting patients to undergo conventional angiography. However, establishing a definite diagnosis still requires some improvements in the delineation of the fine vasculature.

Adolescent↗
PubMed1994

Massive intracerebral hematoma in a child with Klippel-Trenaunay syndrome.

The authors describe a child who suffered from massive intracerebral bleeding due to rupture of a cerebral arteriovenous malformation associated with Klippel-Trenaunay syndrome (KTS). Neurovascular lesions have been regarded as uncommon in KTS; however, our case may indicate the need for neurovascular scrutiny in patients with this syndrome.

Cerebral Hemorrhage↗
PubMed1994

Control of systemic hypertension with diltiazem, a calcium-antagonist, in patients with a mildly elevated intracranial pressure: a comparative study.

A cerebral vasodilatory action could represent a critical adverse effect of any drug used to control the systemic blood pressure (SBP) in patients with an elevated intracranial pressure (ICP), since such an action increases the ICP and thereby reduces the cerebral perfusion pressure (CPP). While several new calcium antagonists are now available, each drug exerts variable dilatory actions on the cerebral, coronary and peripheral vasculatures. Among these agents, diltiazem has been found to be sufficiently potent to control systemic hypertension but to have a less potent dilatory action on the cerebral vasculature in experimental animals. Based on such a characteristic, diltiazem appears to be an ideal drug for controlling systemic hypertension in patients with an elevated ICP. However, little has yet been investigated in the clinical setting. In the present study, the effects of three drugs, i.e., nitroglycerin, nicardipine and diltiazem, on the ICP were analysed retrospectively. Data were collected from patients who had demonstrated a mildly elevated ICP (mean ICP, 10-23 mmHg) and moderate systemic hypertension (mean SBP, 97-125 mmHg) during the period of 72 hours after surgical evacuation of spontaneous intracerebral haematomas. We reviewed the computer-based records of 385 patients, and identified 35 episodes in which the mean SBP was reduced by more than 10 mmHg by one of these three drugs alone during the initial 24 hours after haematoma evacuation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Arteriovenous malformation occluded by Masson's vegetant intravascular haemangioendothelioma and complicated with intracerebral haematoma.

A case of arteriovenous malformation occluded by Masson's vegetant intravascular haemangioendothelioma and complicated with intracerebral haemorrhage in an 18-year-old woman is reported. Marked endothelial proliferation was found in the vascular lumen of draining vein. The haemorrhage appeared to have resulted from impaired venous drainage from the arteriovenous malformation.

Adolescent↗
PubMed1994

Chronic motor cortex stimulation for central deafferentation pain: experience with bulbar pain secondary to Wallenberg syndrome.

Six patients with bulbar pain caused by lateral medullary infarct were treated by stimulation therapy. Dysesthesia on the opposite side of the body was subjected to stimulation therapy in these patients. Of the subjects, 4 underwent thalamic stimulation and 3 were treated by motor cortex stimulation; the effects of both thalamic and motor cortex stimulation were investigated in 1 patient. No satisfactory pain control was obtained by thalamic stimulation in any of the patients in this series. In contrast, 2 of the 3 patients treated by motor cortex stimulation reported satisfactory pain control. The pain inhibition usually occurred at intensities below the threshold for the production of muscle contraction (pulse duration, 0.1-0.5 ms; intensity, 3-8 V). This finding was consistent with our previous observations made in a series of patients with thalamic pain, indicating that motor cortex stimulation is significantly more useful than thalamic stimulation for controlling deafferentation pain secondary to central nervous system lesions. We discuss the possibility that better control of deafferentation pain may be provided by stimulation at a level more rostral to the site of deafferentation.

Adult↗
PubMed1994

Persistent absence of auditory brainstem responses with preserved hearing and recovery from a prolonged comatose state.

A patient with hypertensive intracerebellar haemorrhage, who recovered from impending tonsillar herniation with emergency haematoma evacuation, showed persistent absence of auditory brainstem responses. The patient demonstrated a preserved stapedius reflex and hearing after recovery, indicating that the auditory brainstem pathway was not completely disrupted. We suggest that the loss of the auditory brainstem response (ABR) could be accounted for by impulse asynchrony along the auditory brainstem pathway. The existence of such a case implies that persistent absence of the ABR is not always indicative of irreversible brainstem damage and a poor outcome following severe brain injury.

Brain Damage, Chronic↗
PubMed1994

Surgical management of cavernous malformations of the third ventricle.

In order to determine adequate therapeutic approaches for cavernous malformations of the third ventricle, the authors reviewed a series of five such malformations managed at their institution and nine others reported in the literature. Four subgroups were identified in terms of the site of origin and could be characterized by different clinical manifestations: visual field defects and endocrine function deficits in patients with malformations in the suprachiasmatic region (six cases); symptoms caused by hydrocephalus in those with malformations in the foramen of Monro region (five cases); and deficits of short-term memory in those with malformations in the lateral wall (two cases) or of the floor of the third ventricle (one case). Unlike cavernous malformations at other locations, malformations of the third ventricle frequently demonstrated rapid growth (43%) and mass effects (71%). The surgical or autopsy findings suggested that the growth was attributable to repeated intralesional hemorrhages. Extralesional hemorrhage was also not uncommon, occurring in 29% of patients. Such tendencies require the adoption of a more aggressive approach to this particular group of cavernous malformations as compared to those in other locations. The risks of regrowth and extralesional hemorrhage appear to be reduced only by complete excision. The surgical approaches adopted should be aimed at providing the best access to the site where the malformation has arisen. The translamina terminalis approach for cavernous malformations in the suprachiasmatic region, the transventricular or transcallosal interfornicial approaches for those in the foramen of Monro region and the transvelum interpositum approach for those in the lateral wall or the floor of the third ventricle appear to be appropriate. In order to select the adequate surgical approach, precise diagnosis of the site of origin is crucial. In addition to neuroimaging techniques, the patient's initial symptoms provide valuable information.

Adult↗
PubMed1994

Continuous monitoring of jugular bulb oxygen saturation as a measure of the shunt flow of cerebral arteriovenous malformations.

Jugular bulb oxygen saturation (SjO2) was monitored during preoperative embolization procedures in a consecutive series of 15 patients with large supratentorial arteriovenous malformations (AVM's) in order to test the hypothesis that changes in the shunt flow ratio can be continuously evaluated from the SjO2. A fiberoptic catheter was placed at the dominant jugular bulb. The SjO2 measured using jugular blood withdrawn before embolization was significantly higher than the SjO2 measured at the end of the final embolization procedure (mean +/- standard deviation 84.1% +/- 12.7% vs. 74.2% +/- 10.9%, p < 0.0001), showing a positive correlation with the AVM volume (r = 0.66, p < 0.001). Continuous monitoring of SjO2 via the fiberoptic catheter revealed a progressive decrease in association with the embolization procedures. Microsurgical resection of the AVM was performed at 1 to 2 weeks after the final embolization. Cases in which postoperative hemispheric deformation was revealed on computerized tomography demonstrated a higher SjO2 at the end of embolization compared to that in the remaining cases (81.6% +/- 8.6% vs. 67.8% +/- 8.4%, p < 0.008). Hemispheric deformation was observed in all cases in which the SjO2 did not decline to a level below 90% following embolization. The risk of severe hyperemic complications appeared to be greatly diminished when the SjO2 fell to below 80%. Assuming that the oxygen saturation of the perfusion flow (SjpO2) ranges from 50% to 75%, the ratio of the shunt flow to total flow at an SjO2 of 90% was estimated to be 0.6 to 0.8 based on the following equation: shunt flow/(perfusion flow + shunt flow) = (SjO2 - SjpO2)/(arterial oxygen saturation - SjpO2). These results suggest that monitoring the SjO2 provides real-time information concerning the progress of embolization and helps to determine whether the embolization has progressed sufficiently to avoid postoperative hyperemic complications.

Adolescent↗
PubMed1994

[A study on maximal permissible drug concentration for transnasal medication from the viewpoint of ciliary activity of the cultured human paranasal mucosa].

Aerosol therapy has been widely used for upper and lower airway diseases. However, maximal permissible concentrations of drugs have not yet been clarified. The purpose of this study was to find the maximal drug concentration for transnasal medication that does not inhibit ciliary activity or tissue. Human paranasal sinus mucosa taken at surgery was cut into small pieces. These were cultured in RPMI-1640 medium under the conditions of 5% CO2 and 100% relative humidity at 37 degrees C. Histopathologic damage was observed under a microscope at 400 x magnification. The rate of ciliary beating was measured by a photoelectric method with a cadmium sulphite photometer. In order to compare the findings with those of repeated clinical nebulizer therapy, drug application once a day for 3 days and combined use with steroids were examined for 30 min, considering maximal retention time of the drugs in the nasal cavity as an aerosol therapy. The maximal permissible concentrations of several drugs in single use obtained by these experiments were as follows: acetylcysteine 4.4%, tyloxapol 0.03%, sodium cromoglycate 4%, Broncasma Berna 2 times, prednisolone 1%, dexamethasone 0.2%, betamethasone 0.4%, kanamycin 20%, gentamicine 1%, amikasine 4%, dibekasin 4%, astromysin 4%, fosfomycin 3%, clindamycin 3%, ampicillin 10%, cefazolin 5%, and lidocaine 0.01%. When antibiotics and ateroids were used at the same time, the ciliary activity and the tissue were damaged more strongly than with single use. Therefore, the maximal concentration of some drugs has to be reduced. For example, the maximal concentration of prednisolone, 1%, was reduced to 0.2%, and that of kanamycin, 20%, was changed to 10%.

Acetylcysteine↗
PubMed1994

[The two familial occurrence of von Hippel-Lindau disease].

Five cases of von Hippel-Lindau disease in two families were reported. In one family there were 2 cases in a mother (55 years old) and her daughter (26 years old) which had multiple hemangioblastomas in the optic nerve, cerebellum and spinal cord in each case. Retinal angioma appeared in the case of daughter, but not in the mother. In the other family there were 3 cases in a father (28 years old), his son (11 years old) and daughter (14 years old). All of them had retinal angioma and cerebellar hemangioblastoma. Two cases out of 5 cases in the two families were associated with abdominal organ diseases which were renal cell carcinoma in a case and pancreas cyst in the other. The familial occurrence of von Hippel-Lindau disease in Japan was recognized in 21 families with 103 cases including our cases. On the study of reported cases hemangioblastoma frequently occurred in multiple region such as cerebellum, medulla oblongata and frequently presented with renal cell carcinoma, pheochromocytoma and cyst in pancreas, kidney and liver. The location of hemangioblastoma and combined disease was similar in cases in each family. The age of onset of von Hippel-Lindau disease in the second generation was younger than that of the first generation.

Adolescent↗
PubMed1994

[Turner's syndrome with pituitary hyperplasia: a case report].

Turner's syndrome, a sex-chromosome abnormality, is often accompanied by cardiovascular disorders, such as coarctation of the aorta. We encountered a case of Turner's syndrome with meningioma and pituitary hyperplasia which resulted in death from dissection of the aorta. The patient was 36-year-old female who was diagnosed as having Turner's syndrome of mosaic-type at the age of 15. She had accepted sex-hormone replacement with estrogen and progesterone over 20 years. She lost consciousness and was transferred to our institute on June 20th, 1992. She was in shock but her condition began to improve after intensive treatment. CT scan revealed a calcified mass lesion at the left frontal convexity and a markedly enhanced round mass lesion at the suprasellar region. Angiography showed tumor stain of the suprasellar region fed by the posterior ethmoidal artery. These tumors were diagnosed as multiple meningiomas. She developed dyspnea on June 24th and chest X-ray showed right pleural fluid collection and cardiomegaly. This condition was diagnosed as congestive heart failure. Her condition was getting worse and she suffered abrupt cardiac arrest on June 28th. Autopsy revealed dissection of the aorta as the cause of death. The tumor of the convexity was meningioma, and the suprasellar lesion was diagnosed as pituitary hyperplasia. It is well known that frequent excess dose injection of estrogen can induce pituitary adenoma or hyperplasia in rats. In this case, the presence of pituitary hyperplasia was thought to be the result of long-term injection of estrogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Clinical study on the recurrence of meningiomas: correlating factors for the recurrence and therapeutic prognosis of meningiomas].

Authors have studied 128 cases of meningiomas which were operated on and examined histologically. 12 cases (11.3%) of 106 cases of the meningiomas followed up for more than 5 years after surgery had recurrence after the primary operation. The distribution of age and sex, the tumor location, the histological type, the extent of tumor evacuation and AgNORs counts and BrdU labeling index for the evaluation of tumor proliferation were studied comparatively in the two groups, the recurrent and nonrecurrent meningiomas. 8 cases (19.0%) of 42 cases of the meningiomas in the age-group lower than 50 years old were recurrent cases, whereas 4 cases (6.0%) of 67 cases in the age-group over 50 years old were non-recurrent. Concerning the sex distribution of the meningiomas in our cases recurrent rate was 20.5% among males and 6.0% among females. The tumor locations of the meningiomas did not correlate significantly with recurrence. The extent of tumor removal demonstrated Simpson grade I (47 cases), grade II (37 cases), grade III (17 cases), grade IV (5 cases) on primary operation. Recurrence was found in 11 cases (13.1%) of 84 cases operated on by total removal of Simpson grade I or grade II. 8 cases of 11 cases had recurrence within 5 years after the primary operation of Simpson grade I or II. Total removal of the tumor was important in order to bring about long survival after operation. But correlation between the extent of tumor removal and recurrence was not able to be recognized. Histologically, all of the malignant, atypical and papillary type of meningiomas treated in the primary operations had recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Thalamic neuronal hyperactivity following transection of the spinothalamic tract in the cat: involvement of N-methyl-D-aspartate receptor.

Single neuron activities responding to peripheral stimuli with short latencies were recorded within the thalamic nucleus ventralis posterolateralis (VPL) after transection of the spinothalamic tract (STT) in the cat under alpha-chloralose anesthesia. The VPL neurons showed spontaneous and evoked hyperactivity after STT transection, which was revealed at 1-2 weeks. The spontaneous hyperactivity further progressed until 3-4 weeks. These hyperactivities were observed in core-area neurons as well as neurons found in the shell area, suggesting that some, if not many, of the N-methyl-D-aspartate (NMDA) receptor antagonist (MK-801, 4-16 mg; i.v.) attenuated both the spontaneous and evoked hyperactivity observed after STT transection. No such effects were demonstrated in sham-operated animals. These findings suggest that VPL neurons become hyperactive after STT transection through recruitment of NMDA receptors. The hyperactivity of VPL neurons may represent an important background process in the production of deafferentation pain induced by lesions involving the STT.

Amino Acids↗
PubMed1993

Post-ischemic potentiation of Schaffer collateral/CA1 pyramidal cell responses of the rat hippocampus in vivo: involvement of N-methyl-D-aspartate receptors.

The present study examined the functional changes in the hippocampal CA1 pyramidal cell system in vivo occurring after 12-min forebrain ischemia in the rat. A population excitatory postsynaptic potential and orthodromic population spike of CA1 pyramidal cells to stimulation of the Schaffer collaterals were potentiated at 6-8 h post-ischemia. These changes were not associated with an increase in excitability of the CA1 pyramidal cells as evaluated from the antidromic population spike induced by alveus stimulation, suggesting the presence of an increased synaptic efficacy. The post-ischemic potentiation was prevented by pretreatment with the N-methyl D-aspartate (NMDA) receptor antagonist, MK801, in a dose-dependent manner. These findings suggest that 12-min forebrain ischemia in the rat activates NMDA receptors, which results in an increase in synaptic efficacy to the CA1 pyramidal cells at 6-8 h post-ischemia.

Animals↗
PubMed1993

Magnetic resonance imaging of xanthomatous meningioma.

A case of meningioma with extensive xanthomatous metaplasia occurring in the left frontal convexity of a 37-year-old woman is reported. The tumour was demonstrated as a hypodense mass with minimal enhancement on CT. Our findings suggest that magnetic resonance imaging may provide a clue to the diagnosis of meningiomas with extensive xanthomatous metaplasia when CT is less specific.

Adult↗
PubMed1993

Effects of indeloxazine on hippocampal CA1 pyramidal cell damage following transient cerebral ischemia in the gerbil.

The effects of indeloxazine on the ischemia-induced death of hippocampal CA1 pyramidal cells following transient cerebral ischemia were examined in the mongolian gerbil. Increased survival of CA1 pyramidal cells was demonstrated in animals pre- and post-treated with indeloxazine. Increased survival of CA1 pyramidal cells was, however, not demonstrated in animals post-treated but not pre-treated with indeloxazine. A previous study has demonstrated that indeloxazine increases the glucose and adenosine triphosphate (ATP) contents in the brain probably through an enhanced capability of oxidative phosphorylation. It has been reported that increases in the glucose and ATP contents in the brain before ischemia delay the onset of massive ionic fluxes during ischemia. The delay in onset of this ionic event may help to protect these cells from death. The present data suggest that energy state before ischemia may play an important role in the protective effect of indeloxazine.

Adenosine Triphosphate↗
PubMed1993

Impairment of hippocampal long-term potentiation following transient cerebral ischaemia in rat: effects of bifemelane, a potent inhibitor of ischaemia-induced acetylcholine release.

The present study examined the changes in the long-term potentiation (LTP) of the hippocampal Schaffer collateral/CA1 pyramidal cell system in vivo occurring after 12-min forebrain ischaemia in the rat. A population spike (PS) of CA1 pyramidal cells were recorded in 18 rats at 7 h post-ischaemia. While the threshold and amplitude of pretetanic PS were not depressed, the induction of LTP was significantly impaired following ischaemic insult (155 +/- 28% of baseline PS, mean +/- SD, n = 6, p < 0.001), as compared to sham-controls (337 +/- 84%, n = 5), without reduction of single pulse responses. Pretreatment with 4(o-benzylphenoxy)-N-methylbutylamine hydrochloride (Bifemelane; 50 mg kg-1 i.p.) slightly but significantly attenuated the impairment in LTP induction (196 +/- 23%, n = 6; p < 0.02). The findings in the present study indicate that CA1 pyramidal cells are dysfunctional in synaptic plasticity long before their death. Bifemelane has been demonstrated to inhibit acetylcholine release strongly during cerebral ischaemia but not interfere with normal cholinergic synaptic transmission. The effect of bifemelane suggests that Ach release during ischaemia is partially involved in the post-ischaemic impairment of LTP induction.

Acetylcholine↗