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Biomedical subjects

T Yasui

Publications and source records attributed to T Yasui.

At least 145 records · Page 8Linked to original sources
PubMed1997

Choroidal detachment and dural carotid-cavernous sinus fistula--case report.

A 71-year-old female presented with the rare complication of choroidal detachment after endovascular treatment of a dural carotid-cavernous sinus fistula. Since the residual arteriovenous shunt flow was minimal and intraocular pressure was normal, the choroidal detachment was treated conservatively and disappeared within one month. The possibility of choroidal detachment during the clinical course of a dural carotid-cavernous sinus fistula should be recognized.

Aged↗
PubMed1997

[Intraoperative aneurysmal rupture at the neck].

Intraoperative rupture of an aneurysm can lead to disastrous results when the rupture occurs at the neck. The authors have encountered eight cases (5%) of intraoperative rupture in a series of 155 patients. All patients were operated on in the acute stage by one of the authors of this paper (T.Y.). In six cases, the aneurysm ruptured at the dome and in two, at the neck. We report these two patients with intraoperative rupture at the neck. The first case, a 50-year-old female, developed SAH, but a 4-vessel study failed to show an aneurysm. The second series of angiograms obtained ten days later showed a broad-based, left proximal A1 aneurysm. It was decided to employ a right pterional approach. The aneurysm was arising from the right A1 segment just proximal to the anterior communicating artery. The neck was wide, with thin walls. Thus, it seemed better to apply a clip parallel to the A1 segment axis than to apply it from a direction perpendicular to the A1 segment axis. However, the right pterional approach precluded a parallel clipping, so the blades of a clip were applied perpendicularly. The clip seemed not to be completely across the neck of the aneurysm. After applying a temporary clip to the A1 segment proximal to the aneurysm, the clip blades were opened and advanced just when bursting of the sac at the base occurred and microvascular suture repair was required to control the bleeding. The second case, a 57-year-old female, underwent clipping of a right IC-PC aneurysm. However, two years postoperatively, the patient again suffered SAH. Cerebral angiography at this time revealed a relatively large recurrent IC-PC aneurysm in which the old clip was situated on the dome of the aneurysm. Aneurysmal clipping was performed on the day of rupture. Tough granular tissue was removed from the ICA, PcomA, aneurysmal neck, and the old clip. After the true neck was identified, a straight clip was applied to the neck parallel to the ICA. Soon after the clipping, arterial bleeding occurred near the neck. The ruptured aneurysm was trapped using two temporary clips. A curved clip was applied to the ruptured neck, including the wall of the ICA, to control the bleeding. This clipping caused a substantial stenosis of the ICA. Both patients demonstrated postoperative neurological deficits due to ischemia caused by temporary clipping. These encounters dramatically demonstrated that a very thin-walled aneurysm or a recurrent aneurysm has a fragile neck. In surgical treatment of these unusual aneurysms, a clip should be placed on the neck parallel to the parent artery. Furthermore, temporary clipping is advisable when dissecting the neck or applying the clip to the neck to reduce the damage to the neck.

Aneurysm, Ruptured↗
PubMed1997

The accessory middle cerebral artery as a collateral blood supply.

We describe two cases of acute embolic occlusion of the internal carotid artery and the middle cerebral artery in association with a patent accessory middle cerebral artery. Because of the presence of the accessory middle cerebral artery, the frontal lobe was salvaged to some extent, but it did not provide sufficient collateral blood supply to the middle cerebral artery territory to spare the rest of the frontal lobe, the temporal lobe, and the basal ganglia.

Aged↗
PubMed1997

[Rupture of previously documented asymptomatic saccular intracranial aneurysms].

The authors report four cases of patients with documented asymptomatic intact aneurysms that subsequently ruptured. Case 1 involves a 64-year-old woman who had two unruptured aneurysms, i.e., an anterior communicating artery aneurysm and a posterior inferior cerebellar aneurysm, both were discovered during evaluation of cerebral ischemic symptoms. At that time, only the posterior inferior cerebellar aneurysm was clipped. Seven years later, the patient bled fatally from a 5-mm untreated anterior communicating artery aneurysm that had measured approximately 3 mm on an angiogram obtained 7 years earlier. Case 2 is that of a 50-year-old woman who bled from an anterior communicating artery aneurysm that had been discovered 6 years earlier when she suffered subarachnoid hemorrhage (SAH) from a left middle cerebral artery aneurysm. At that time, she had refused surgery for the anterior communicating artery aneurysm. She recovered well from the second SAH. Case 3 is that of a 74-year-old woman who bled from a left paraclinoid internal carotid artery aneurysm that had been discovered incidentally 3 years earlier during evaluation of vertigo. She had not agreed to have a clipping at that time the aneurysm was first discovered because of her age and the difficult location of the aneurysm. She eventually made an uneventful recovery. In the fourth case, during evaluation of cerebral ischemic symptoms, a 59-year-old man was discovered to have a large basilar bifurcation aneurysm. He underwent a craniotomy for clipping of the aneurysm. The aneurysm, however, was unclippable and was instead coated with Bemsheet. Four months later, the patient bled from the aneurysm and entered a vegetative state. The indications for surgery on unruptured asymptomatic cerebral aneurysms are still unclear. The cases reported herein show that asymptomatic aneurysms, especially anterior communicating aneurysms and aneurysms once exposed surgically, do carry a certain risk for future hemorrhage and should not be dismissed as innocuous. Neurosurgeons have recognized the importance of considering life expectancy in managing patients with asymptomatic, unruptured, intracranial aneurysms. With the rapid aging of the population, withholding aneurysm surgery merely because a patient is elderly may not necessarily be the most appropriate decision.

Aged↗
PubMed1997

[Management of subarachnoid hemorrhages without detectable aneurysm].

In this study, 21 patients with subarachnoid hemorrhage (SAH) but negative angiography were evaluated. Angiography was performed twice on each patient, that is, on admission and at 2 weeks following admission. All patients had severe headache of sudden onset, a characteristic manifestation of SAH. Clinical grades on admission (Hunt and Kosnik classification) were generally good: 17 patients were in grade I or II and 4 patients were in grade III. SAH was confirmed by the presence of subarachnoid clot on CT in all cases. Based on the distribution of SAH, CT findings were classified into two patterns, i.e., perimesencephalic and non-perimesencephalic patterns. Four patients showed the perimesencephalic pattern and the remaining 17 the non-perimesencephalic. The period of follow-up ranged from 20 days to 11 years 6 months, with a mean of 6 years 10 months. Except for three recent cases, the mean follow-up period in 8 years 9 months. Exploratory craniotomies probing for aneurysms have been performed in four patients, but no aneurysms have been found in any of these cases. Clinical deterioration associated with vasospasm was observed in one patient. A communicating hydrocephalus requiring a shunting procedure was observed in three patients showing the non-perimesencephalic type CT pattern. Rebleeding occurred in one patient who subsequently died of what may be a dissecting aneurysm of the vertebral artery. One patient who was able to return to full activity experienced symptoms attributable to SAH such as frequent headaches and increased fatigability. Complete recovery was observed in the remaining 19 patients. Two of them, however, later died due to myocardial infarction and aging, respectively. Given these generally positive outcomes, it should be possible to inform such patients of the benignity of their condition. Angiography may not demonstrate a ruptured aneurysm on initial examination in all cases of aneurysmal SAH. Serial angiography, however, can provide a definite diagnosis of the dissecting aneurysm. Therefore, repeat angiography, particularly, when possible, digital subtraction angiography, is necessary to rule out aneurysmal SAH. While small aneurysms or microaneurysms are often found through exploratory craniotomy, we do not agree with the opinion that surgery may be appropriate for certain patients with SAH but with negative angiography. The natural history concerning rebleeding in such cases, as well as morbidity and mortality associated with hemorrhage, remains to be defined. Furthermore, there are reservations regarding whether coagulation of these abnormalities with bipolar cautery constitutes definitive treatment.

Adult↗
PubMed1997

Reversible pontine ischemia caused by acetazolamide challenge.

We report the findings in a patient with a midbasilar artery stenosis in whom reversible ischemic neurologic deficits developed during cerebral blood flow imaging with acetazolamide challenge. The potential for ischemic complications from acetazolamide challenge is discussed.

Acetazolamide↗
PubMed1997

Correlation between vasodilatation and secretion in the lacrimal gland elicited by stimulation of the cornea and facial nerve root of the cat.

PURPOSE: To determine whether reflex vasodilatation can be elicited in the cat lacrimal gland by electrical stimulation of the cornea, whether the vasodilatation elicited by electrical stimulation of the facial nerve root found to be the efferent arm of the cornea-lacrimal gland reflex pathway correlates with the evoked secretion in the lacrimal gland, and what kind of receptors and which autonomic ganglia are involved in lacrimal vasodilator and secretory responses. METHODS: Electrical stimulation of the cornea or facial nerve root was used to evoke a blood flow increase in the lacrimal gland and tear secretion of the urethane-chloralose-anesthetized, paralyzed, and cervically sympathectomized cat. RESULTS: The lacrimal vasodilator response depended on stimulus intensity and frequency and correlated well with the tear secretion. Injection of 2% lidocaine solution into the retrobulbar area, where the pterygopalatine ganglion is located, abolished the vasodilator and the secretory responses. Pretreatment with hexamethonium (an autonomic ganglion blocker) greatly attenuated the secretory response, even at a low dose (1 mg/kg given intravenously), although at this dose, the vasodilator response was only slightly affected. Neither phentolamine (an alpha-adrenoceptor antagonist) nor propranolol (a beta-adrenoceptor antagonist), nor a vasoactive intestinal peptide antagonist had any effect on the vasodilator or secretory responses. Scopolamine (a muscarinic receptor antagonist), although having no effect on vasodilatation, had a profound inhibitory effect on the secretory response. CONCLUSIONS: These results suggest that whereas the vasodilator and secretory responses in the lacrimal gland were well correlated, they were mediated by different mechanisms.

Adrenergic alpha-Antagonists↗
PubMed1997

Direct extracranial-intracranial bypass for children with moyamoya disease.

To improve cerebral hypoperfusion in the ischemic type of Moyamoya disease, we have applied superficial temporal artery-middle cerebral artery (STA-MCA) double anastomoses in combination with encephalo-myo-synangiosis (EMS) for 19 hemispheres of 10 children (age from 5 to 11 years at surgery). Two branches of the STA were anastomosed to the two cortical arteries which were selected in the watershed area of the cerebral hemisphere estimated as a hypoperfusion area on the preoperative angiograms. Before surgery transient ischemic attacks (TIAs) developed from every month to every 6 months in association with hyperventilation or sobbing. No perioperative completed stroke or wound complications was observed, although single TIA developed in four patients within 1 month after surgery. Postoperative angiogram demonstrated that, not only the preoperative watershed area, but also the most of the middle cerebral artery territory was oppacified via the 2 branches of the STA in all 19 hemispheres. In a mean follow-up period of 4 years, no ischemic episode was induced by hyperventilation, and there was no mental or neurological deterioration. STA-MCA double anastomoses, to the cerebral watershed area, in combination with EMS are safe and effective even for younger children with Moyamoya disease.

Anastomosis, Surgical↗
PubMed1997

[A case of microscopic polyangitis accompanied by hearing loss as the initial sign of the disease].

Here we report a case of microscopic polyangitis (MPA) with anti-neutrophil cytoplasmic antibodies against myeloperoxidase (MPO-ANCA) accompanied by perceptive dominant hearing loss as the initial sign of the disease. A 52-year-old woman was admitted to Tokyo Metropolitan Ohtsuka Hospital in April 1996 because of bilateral progressive hearing loss. On admission, she had presented bilateral perceptive hearing loss, fever, myalgia, and weight loss. Laboratory data showed accelerated erythrocyte sedimentation rate, proteinuria, microscopic hematuria, leukocytosis, hypoproteinemia, and elevated creatinine level. Serum level of MPO-ANCA was elevated. Chest X-ray and computed tomography showed mild pleural effusion and interstitial shadow in bilateral lung fields. The biopsy findings detected that focal glomerulonephritis, and necrotizing angitis of small artery in kidney. The diagnosis of MPA was made with clinical course, laboratory findings, radiographic findings, and biopsy finding. Treatment was initiated with 45 mg of prednisolone, followed by marked improvement of hearing loss and decreased titer of serum MPO-ANCA. There are only seven reports showing hearing loss as the initial sign of the disease occurred in polyarteritis nodosa and MPA. The present case suggests the possibility that hearing loss may be the symptom of MPO-ANCA associated vasculitis.

Anti-Inflammatory Agents↗
PubMed1996

Very poor prognosis in cases with extravasation of the contrast medium during angiography.

BACKGROUND: The rebleeding of a ruptured intracranial aneurysm in the acute stage has been thought to indicate a very poor prognosis. In our experience, the outcome of patients with extravasation of the contrast medium is worse than that of patients with rerupture under circumstances other than angiography. We demonstrated the poorer outcome of the patients with extravasation, compared to that of the patients developing rerupture under circumstances other than angiography, and examined the factors that contributed to the poorer outcome of the patients with extravasation. METHODS: Among the 641 cases of ruptured intracranial aneurysm, we have handled over the past 10 years, 36 (5.6%) patients have rebled before surgery was performed. Thirteen patients rebled during angiography (Group I), and the remaining 23 patients rebled in other circumstances (Group II). We compared the outcome of both groups. RESULTS: The rebleeding occurred within 6 hours of the initial rupture in 29 (80%) patients. The outcome of Group I was significantly poorer than that of Group II (p < 0.05). In Group I, SD was achieved in only 1 patient and the remaining 12 patients died, while in Group II, 8 patients were in GR or MD, 2 were in SD, and the remaining 13 patients died. CONCLUSION: Because rebleeding during angiography most often occurs in the acute stage and because the outcome of patients with extravasation is very poor, we recommend that the performance of angiography be delayed at least between 3 and 6 hours after the initial rupture.

Adult↗
PubMed1996

Protective role of CD40 in Leishmania major infection at two distinct phases of cell-mediated immunity.

CD40-deficient mice are susceptible to Leishmania major infection while their wild-type littermates can resolve the infection. Upon stimulation with L. major antigens, draining lymph node T cells of the mutant mice and the susceptible mice, BALB/c, secrete comparable amounts of IL-4. The mutant mice produce less IFN gamma than wild-type mice. The expression of IL-12 p40 mRNA was significantly lower in L. major antigen-stimulated cells of mutant mice than those of wild-type or BALB/c mice. In normal mice, engagement of CD40 activates macrophages to a leishmanicidal state in vitro in the presence of IFN gamma. The results suggest that the CD40-CD40 ligand interaction plays an important role in two critical steps of cell-mediated immunity to L. major infection: the generation of a Th1 response and activation of macrophages to a leishmanicidal state.

Animals↗
PubMed1996

Profound reduction of mature B cell numbers, reactivities and serum Ig levels in mice which simultaneously carry the XID and CD40 deficiency genes.

It has been known for some time that single mutant nude or CD40T mice have apparently normal numbers of cells in the precursor compartments of bone marrow and the mature B cell compartments of the periphery. X-linked immunodeficiency (XID) mice are deficient only in some of the sIgM+sIgD+ B cells. We have investigated further the contributions of the xid mutation, of the T cell deficiency of nude of the inability of CD40T cells to cooperate with T cells in the generation of the precursor and the mature B cell compartments in mice. Double mutant XID/nu and XID/CD40T mice have precursor B cell compartments that are no more deficient than the single mutant XID mice. However, the peripheral B cell compartments of both XID/mu and XID/CD40T are even more deficient than those of single mutant XID mice. While 10% of the peripheral B cells of wild-type or CD40T, one-third of XID and half of XID/nu mice turn over rapidly, as many as three-quarters of those in XID/CD40T are short-lived. Total numbers of sIgM+sIgD+ B cells in the spleen are at best 10-15% of normal mice at 6-8 weeks of age in XID, XID/nu and XID/CD40T mice. They remain that low at 3 months of age in XID/CD40T mice, while in XID mice these peripheral B cells slowly build up in numbers with age. As expected, double mutant XID/CD40T mice do not respond to the T-dependent antigen keyhole limpet hemocyanin. Only the responses to the T-independent type I antigen, TNP-lipopolysaccharide (LPS), appear to be normal. In vitro, their splenic B cells respond poorly to LPS or to IgM-specific antibody in either the absence or presence of cytokines. Most notably, serum IgM, IgG2b or IgG3 levels are severely depressed, while IgG1, IgG2a and IgA levels are < 10 micrograms/ml. These results suggest a model of mature B cell development in which the peripheral, mature B cell compartments are generated in two parallel, not tandemly organized pathways. They could be selected and/or stimulated at the transition from immature to mature B cells: in btk controlled or in CD40 controlled ways.

Animals↗
PubMed1996

Molecular biological analysis of the effects of ginsenoside-Rb2 on albumin mRNA in streptozotocin-induced diabetic rats.

The mechanisms of the mRNA synthesis-promoting action of ginsenoside-Rb2, were investigated at the gene level. Rot analysis suggested that the previously reported increase in RNA polymerase activity as a result of administration of ginsenoside-Rb2 might be because of its effect on a specific gene. In this regard, albumin mRNA, which is expressed specifically in the liver, was assayed by northern blot hybridization using albumin cDNA in normal rats, diabetic control rats and diabetic rats given ginsenoside-Rb2. When the level of albumin mRNA in normal rats was set at 100, the level was reduced markedly to 32 in diabetic control rats. In contrast, in diabetic rats given ginsenoside-Rb2 the level was 0.54, significantly higher (69%) than that in diabetic rats given no ginsenoside-Rb2. In addition, poly(A)+RNA was purified from total RNA and subjected to hybridization, and poly(A)+RNA bands with different charges were measured by densitometry. The results of the measurement revealed changes dependent on the charge, and this was confirmed by autoradiography. We found no significant difference in the transcription activity of albumin mRNA, however, it showed only a tendency to increase. This suggests that ginsenoside-Rb2 has some effect on post-transcriptional regulation of the stability of mRNA itself. The results of Rot analysis suggest that ginsenoside-Rb2 affects a specific gene alone.

Albumins↗
PubMed1996

Regulation of human papillomavirus transcription by the differentiation-dependent epithelial factor Epoc-1/skn-1a.

Human papillomavirus (HPV) early gene expression is closely linked to the differentiation status of infected epithelial cells. Typically, HPV type 16 (HPV16) or HPV18 E6 and E7 transcripts are only barely detectable within the undifferentiated basal cell layer, but their levels increase concomitantly with higher degrees of epithelial cell differentiation in suprabasal cells. A similar differentiation-dependent distribution of expression has been reported for the recently cloned epithelial cell specific transcription factor Epoc-1/skn-1a. We therefore examined whether Epoc-1/skn-1a may be directly involved in the activation of HPV E6/E7 transcription. Transient transfection studies showed that Epoc-1/skn-1a specifically stimulated the HPV16 and HPV18 E6/E7 promoters. Moreover, ectopically expressed Epoc-1/skn-1a was sufficient to stimulate HPV transcription also in nonepithelial cells. By deletion analyses, the Epoc-1/skn-1a-responsive element was mapped to the promoter-proximal portion of the HPV18 transcriptional control region. Footprint analyses and gel retardation assays demonstrated direct binding of Epoc-1/skn-1a to a hitherto uncharacterized site within this region. Mutation of the Epoc-1/skn-1a recognition site within the context of the complete HPV18 upstream regulatory region inhibited Epoc-1/skn-1a-mediated transactivation. These results show that Epoc-1/skn-1a can directly activate the E6/E7 promoter by binding to the viral transcriptional control region. Thus, Epoc-1/skn-1a may be involved in the differentiation-dependent regulation of HPV transcription.

Base Sequence↗
PubMed1996

Transient monocular blindness during manual carotid compression for carotid-cavernous sinus fistulas--two case reports.

Transient monocular blindness occurred during manual carotid compression in two patients with a traumatic direct and a spontaneous dural arteriovenous carotid-cavernous sinus fistula. Ocular complication may occur during diagnostic or therapeutic carotid compression for carotid-cavernous sinus fistulas, so patients should be informed of this possibility. Ocular examination should be repeated during carotid compression to prevent sequelae of ischemic oculopathy.

Arteriovenous Fistula↗
PubMed1996

Vein of Galen aneurysmal malformation in a neonate treated by endovascular surgery--case report.

A male neonate with vein of Galen aneurysmal malformation developed fetal heart failure after a gestation period of 37 weeks. Labor was induced, but a cesarean section had to be performed because of fetal distress. His Apgar scores were 2/8 at birth. The boy required controlled ventilation due to generalized seizure and cyanosis. Neuroimaging revealed vein of Galen aneurysmal malformation with enormous arteriovenous shunt flows. Transarterial embolization was performed on days 4 and 6 to reduce the progressive high-output congestive heart failure. Three large feeders were occluded with interlocking detachable coils, markedly reducing the shunt flow. Although heart failure improved markedly, he died of pulmonary hemorrhage on day 12. Endovascular surgery can improve the prognosis of heart failure in the neonatal period less invasively than other treatment modalities, and may help to minimize ischemic brain damage and thus increase the possibility of normal brain maturation.

Arteriovenous Fistula↗