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Biomedical subjects

N Kuwayama

Publications and source records attributed to N Kuwayama.

At least 19 recordsLinked to original sources
PubMed2005

Hemodynamic status and treatment of aggressive dural arteriovenous fistulas.

In this study the hemodynamic status and treatment modality of aggressive dural arteriovenous fistulas (dAVFs) was evaluated. Of 145 intracranial dAVFs treated in our clinic, there were 38 aggressive lesions presenting with hemorrhage, infarction, seizures, and symptoms of increased intracranial pressure. They included 3 (5% of all cavernous sinus lesions) cavernous sinus, 24 (44%) transverse-sigmoid and superior sagittal sinus, and 11 (46%) direct cortical types of dAVFs. Of these 38 aggressive lesions, retrograde leptomeningeal venous drainage was disclosed in 35 lesions, and retrograde sinus drainage in 3. Eighteen cases were treated only with endovascular procedures, 7 with surgical interventions, and 13 with combined endovascular and surgical procedures. Angiographic results were complete obliteration in 66% of the cases, subtotal and partial obliteration in 34%. Clinical outcome was GR (good recovery) in 58% of cases, MD (moderate disability) in 18%, SD (severe disability) in 13%, VS (vegetative state) in 8%, and D (death) (due to acute cardiac infarction) in 3%. Symptomatic procedural complication occurred in 3 cases. In conclusion, aggressive dural AVF resulted from retrograde leptomeningeal venous drainage. Combined surgical and endovascular treatment played the leading part in the management of this aggressive type of lesion.

Adult↗
PubMed2001

An antimicrotubule agent, TZT-1027, does not induce neuropathologic alterations which are detected after administration of vincristine or paclitaxel in animal models.

One of the major dose-limiting toxicities induced by antimicrotubule antitumor agents such as vinca alkaloids and taxanes is peripheral neuropathy. The neurotoxicity of TZT-1027 (a dolastatin 10 derivative antimicrotubule agent) was thus assessed using the animal models for antimicrotubule agent-induced neurotoxicity. Rabbits were intravenously given TZT-1027 or vincristine weekly for 5 weeks. In the mouse study, TZT-1027, vincristine or paclitaxel was intravenously given every 2 days and/or weekly. Despite the neuropathologic evidence such as myelinated axonal and fiber degeneration in the peripheral nerves and in the sensory tracts of the spinal cord following the treatment with vincristine or paclitaxel, no drug-induced alteration was observed in the TZT-1027 groups. Although there are reports that some other dolastatin derivatives with antimicrotubule activity showed no neurotoxic potential in humans, the present study represents the first demonstration in experimental animals that a dolastatin derivative has no, or at least a lower, neurotoxic potential compared to other antimicrotubule agents.

Animals↗
PubMed2001

Intracranial hemorrhage associated with congenital organic disease in neonates. Report of two cases and review of literature.

We report on two patients with intracranial hemorrhage associated with primary organic lesions who underwent surgery within 24 h after birth. The primary lesions in the two cases were an arteriovenous malformation (AVM) and a brain tumor. The patient with AVM has exhibited normal growth without neurological deficits during follow-up over 18 years, but the patient with brain tumor has exhibited various degrees of neurological deficits and developmental retardation. Timely diagnosis and aggressive surgery may be required for the management of neonatal AVMs with intracerebral hemorrhage.

Adolescent↗
PubMed2001

[Systemic non-Hodgkin lymphoma initially presented with visual disturbance due to intrasellar lymphoma--a case report].

A case with systemic non-Hodgkin lymphoma involving the sella turcica and kidney is reported. A 69-year-old man presented with a progressive two month history of visual disturbance and headache. Neurological examination revealed bilateral visual disturbance and right optic atrophy. MRI showed a contrast-enhancing mass in the sella turcica. The tumor extended to the right optic nerve. Without extensive studies for systemic disease, the patient immediately underwent transsphenoidal surgery. The slightly firm, fibrous and vascular-rich tumor was subtotally removed. The histopathological examination revealed a malignant lymphoma, diffuse-large-cell type with B-cell phenotype. The postoperative course was uneventful and the patient's symptoms subsided gradually. The patient received radiation therapy and the tumor disappeared. Postoperative CT examinations of the abdomen and pelvis revealed a large mass at the upper portion of the left kidney. Ga-scan also suggested the mass to be consistent with the abdominal CT. However, the patient suddenly died of acute heart failure with unknown cause just before starting chemotherapy for systemic lymphoma. Patients presenting primary central nervous system lymphoma (PCNSL) may have systemic non-Hodgkin lymphoma. To exclude systemic non-Hodgkin lymphoma, systemic investigation is essential for the initial management of patients presenting PCNSL.

Aged↗
PubMed2001

[Dural arteriovenous fistula of the anterior cranial fossa associated with occlusion of the internal carotid artery: a case report].

We reported a case with dural arteriovenous fistula (dAVF) of the anterior cranial fossa associated with occlusion of the left cervical internal carotid artery. A 73-year-old man was admitted with total aphasia and right hemiparesis. Computed tomography showed an ischemic lesion of the left cerebral hemisphere and old infarction of the left occipital lobe. Angiography revealed occlusion of the left cervical internal carotid artery and dAVF of the anterior cranial fossa, fed by the left middle meningeal and the right anterior ethmoidal artery. Follow-up angiography revealed spontaneous recanalization and severe arteriosclerosis of the left internal carotid artery. After marked improvement of neurological deficits, the patient underwent surgical clipping of the draining veins to occlude the dAVF of the anterior cranial fossa. We speculated that marked development of the collateral circulation from the external carotid system might result in the occurrence of dAVF of the anterior cranial fossa.

Aged↗
PubMed2000

Endovascular treatment of unusual multiple aneurysms of the internal carotid artery-posterior communicating artery complex--case report.

A 79-year-old female presented with subarachnoid hemorrhage due to rupture of a rare true posterior communicating artery (PCoA) aneurysm and with poor general condition. Endovascular therapy was performed in the chronic stage. Right carotid angiography just before embolization demonstrated unusual multiple aneurysms of the internal carotid artery (ICA)-PCoA complex. Superselective angiography and aneurysmography using microcatheter revealed two separate aneurysms arising from the PCoA and the ICA-PCoA junction. Endovacular embolization using Guglielmi detachable coils (GDCs) was successfully performed for both aneurysms and complete occlusions were achieved with the PCoA fully patent. Embolization with GDCs is a good alternative to surgical clipping for PCoA aneurysm after careful evaluation of superselective angiography.

Aged↗
PubMed1999

Low-dose intramuscular polymyxin B improves survival of septic rats.

UNLABELLED: Polymyxin B (PLB) is a cationic antibiotic that also stoichiometrically neutralizes the lipid A moiety of endotoxin. We examined effects of a small dose of PLB on the mortality of rats with cecal ligation and puncture, on LPS-stimulated nitric oxide (NO) production, and on tumor necrosis factor alpha (TNF alpha) production by isolated rat Kupffer cells. MATERIALS AND METHODS: In vivo studies: Cecal ligation and puncture (CLP) was performed under anesthesia in 28 rats. One hour after CLP, either 600 U/kg of PLB or saline was administered intramuscularly every 6 h (PLB group: n = 12; control group: n = 16). Plasma endotoxin was measured at 3 and 24 h after the CLP by the Endospecy test. This was compared with survival. IN VITRO STUDIES: Kupffer cells were isolated from the normal rat liver. The cells were incubated with LPS or LPS + PLB. After 24 h, NO and TNF alpha content were measured using the Griess and ELISA methods, respectively. RESULTS: Low dose PLB significantly decreased the endotoxin levels at both 3 and 24 h (5.5 +/- 2.1 pg/mL vs. 32.8 +/- 3.6 at 3 h; 26.1 +/- 6.1 vs. 49.1 +/- 5.6 at 24 h (p < .05) after CLP. PLB significantly improved survival of CLP rats (68.8% in the control group vs. 100% in the PLB treated group on 3 days after CLP, p < .001). PLB also attenuated NO and TNF alpha production from the Kupffer cells. CONCLUSION: Intramuscular PLB administered in low doses may improve the mortality of sepsis.

Animals↗
PubMed1998

Vasa vasorum of the intracranial arteries.

Most of the major extracranial arteries have vasa vasorum which play an important role in some pathological conditions. However, in the intracranial arteries, the existence of vasa vasorum and their pathological implication have not been adequately investigated. We examined the distribution and incidence of vasa vasorum in the major cerebral arteries and their relationships to certain clinical factors in 50 autopsy cases performed between 1987 and 1994. By light microscopy, vasa vasorum were found in 36 of 50 patients. Of 36 patients, vasa vasorum in 30 cases were localizedly observed in the tunica adventitia and the in other 6 were distributed in the tunica media accompanied by intramural haemorrhage. Existence of vasa vasorum was more common in the proximal arteries (vertebral, internal carotid, and basilar arteries) than in the distal arteries (middle cerebral and anterior cerebral arteries). Vasa vasorum were found more frequently in aged patients with severe atherosclerosis and those with cerebrovascular diseases. Our results indicated that intracranial vasa vasorum existed with a higher frequency in the tunica adventitia of the vertebral and internal cerebral arteries, and the incidence of vasa vasorum related to severity of atherosclerosis. The development of vasa vasorum in the tunica media may reflect some pathological changes of cerebral arteries.

Adolescent↗
PubMed1998

Consequences of vascular flow on lung injury induced by mechanical ventilation.

To investigate whether the magnitude of blood flow contributes to ventilator-induced lung injury, 14 sets of isolated rabbit lungs were randomized for perfusion at either 300 (Group A: n = 7) or 900 ml/ min (Group B: n = 7) while ventilated with 30 cm H2O peak static pressure. Control lungs (Group C: n = 7) were ventilated with lower peak static pressure (15 cm H2O) and perfused at 500 ml/min. Weight gain, changes in the ultrafiltration coefficient (DeltaKf) and lung static compliance (CL), and extent of hemorrhage (scored by histology) were compared. Group B had a larger decrease in CL (-13 +/- 11%) than Groups A (2 +/- 6%) and C (5 +/- 5%) (p < 0.05). Group B had more hemorrhage and gained more weight (16.2 +/- 9.5 g) than Groups A (8.7 +/- 3.4 g) and C (1.6 +/- 1.0 g) (p < 0.05 for each pairwise comparison between groups). Finally, Kf (g . min-1 . cm H2O-1 . 100 g-1) increased the most in Group B (DeltaKf = 0.26 +/- 0. 20 versus 0.17 +/- 0.10 in Group A and 0.05 +/- 0.04 in Group C; p < 0.05 for B versus C). We conclude that the intensity of lung perfusion contributes to ventilator- induced lung injury in this model.

Animals↗
PubMed1998

Direct packing of the isolated sinus in patients with dural arteriovenous fistulas of the transverse-sigmoid sinus.

OBJECT: The goal of this study was to evaluate the efficacy of direct packing of the isolated sinus (occluded both distally and proximally) in patients with dural arteriovenous fistulas (AVFs) of the transverse-sigmoid sinus. METHODS: Eight patients were included in this study. There were seven men and one woman, ranging in age from 47 to 75 years (mean 60.4 years). Five patients presented with intracranial hemorrhage or venous infarction, one with convulsions, and two with pulsatile tinnitus. Prominent retrograde cortical venous drainage due to sinus isolation was angiographically demonstrated in all patients. All patients were treated by a small craniotomy and direct sinus packing with microcoils; the procedure was performed with the aid of digital subtraction angiography. Five patients were pretreated with transarterial embolization to reduce arterial inflow before the procedure, and intrasinus pressure and sinus blood gases were monitored throughout the operation. Postsurgery, the dural AVF was completely obliterated in all patients. The sinus pressure was 29 to 58% of systemic blood pressure, and sinus blood gas levels were purely arterial before packing. There was no morbidity related to direct sinus packing; however, one patient died as a result of acute myocardial infarction. Over a follow-up period ranging from 1 to 5 years, a faint asymptomatic dural AVF recurred in one patient on the cortex adjacent to the occluded sinus but regressed spontaneously within 1 year. CONCLUSIONS: Direct sinus packing was found to be highly effective for the treatment of dural AVFs that empty into the isolated sinus. Measurement of changes in sinus pressure and sinus blood gas levels was useful for monitoring the progress of direct sinus packing.

Aged↗
PubMed1998

Surgical transvenous embolization of a cortically draining carotid cavernous fistula via a vein of the sylvian fissure.

Percutaneous transvenous embolization is one of the most effective treatments of intracranial dural arteriovenous fistulas (AVFs) involving the dural sinuses. We present a unique case of surgical transvenous embolization in a 48-year-old man with a dural AVF of the cavernous sinus who presented with intracerebral hematoma. The dural AVF drained only into the vein of the sylvian fissure on angiography. Transvenous embolization via the vein of the sylvian fissure during craniotomy obliterated the AVF completely.

Arteriovenous Fistula↗
PubMed1997

Elevation of platelet activating factor, inflammatory cytokines, and coagulation factors in the internal jugular vein of patients with subarachnoid hemorrhage.

The aim of the present study was to examine the changes of inflammatory and coagulation factors in blood of the internal jugular vein, not of peripheral vein, in patients with subarachnoid hemorrhage (SAH). The results show that while interleukin-6 (IL-6) and platelet activating factor (PAF) concentrations increased within first 4 days after SAH and remained elevated up to 14 days, interleukin-1 beta (IL-1 beta) showed a transient increase between 5-9 days after SAH and tumor necrosis factor-alpha (TNF-alpha) remained unchanged. Also different coagulation factors were increased between 5-9 days after SAH. Moreover, patients with delayed ischemic neurological deficits (DIND) displayed the highest levels of PAF and the coagulation factors, von Willebrand factor (vWF) and thrombin-antithrombin III complex (TAT). These results suggest that elevation of PAF and other inflammatory cytokines following SAH may cause the hypercoagulation state that is associated with cerebral vasospasm and internal jugular vein may be more adequate vessel for sampling blood to examine these factors.

Adult↗
PubMed1997

Leptomeningeal melanoma associated with straight sinus thrombosis--case report.

A 36-year-old female was admitted with leptomeningeal melanoma associated with straight sinus thrombosis manifesting as headache and vomiting. Computed tomography and magnetic resonance imaging showed the subarachnoid space was diffusely enhanced. Her consciousness rapidly deteriorated to a coma. Angiography demonstrated straight sinus thrombosis. Thrombolysis by superselective catheterization and infusion of urokinase was successfully performed. She recovered consciousness, but developed paraparesis 2 weeks later. Malignant melanoma with meningeal dissemination was diagnosed by an open biopsy of the lumbar lesion. Angiitis induced by the infiltration of tumor cells and activation of the blood coagulation cascade was probably the causative mechanism of the sinus thrombosis.

Adult↗
PubMed1996

Effects of different triggering systems and external PEEP on trigger capability of the ventilator.

OBJECTIVE: The triggering capability of both the pressure and flow triggering systems of the Servo 300 ventilator (Siemens-Elema, Sweden) was compared at various levels of positive end-expiratory pressure (PEEP), airway resistance (R(aw)), inspiratory effort and air leak, using a mechanical lung model. DESIGN: The ventilator was connected to a two bellows-in-series-type lung model with various mechanical properties. Lung compliance and chest wall compliance were 0.03 and 0.121/cmH2O, respectively. R(aw) was 5, 20 and 50 cmH2O/l/s. Respiratory rate was 15 breaths/min. To compare the triggering capability of both systems, the sensitivity of pressure and flow triggered pressure support ventilation (PSV) was adjusted to be equal by observing the triggering time at 0 cmH2O PEEP and 16 cmH2O of pressure support (PS) with no air leak. No auto-PEEP was developed. In the measurement of trigger delay, the PS level ranged from 16 to 22 cmH2O to attain a set tidal volume (V(T)) of 470 ml at a R(aw) of 5, 20 and 50 cmH2O/l/s. The PEEP level was then changed from 0, 5 and 10 cmH2O at a PS level of 17 cmH2O and R(aw) of 5 and 20 cmH2O/l/s, and the trigger delay was determined. The effect of various levels of air leak and inspiratory effort on triggering capability was also evaluated. Inspiratory effort during triggering delay was estimated by measurements of pressure differentials of airway pressure (Paw) and driving pressure in the diaphragm bellows (Pdriv) in both systems. MEASUREMENTS AND RESULTS: There were no significant differences in trigger delay between the two triggering systems at the various PEEP and R(aw) levels. At the matched sensitivity level, air leak decreased trigger delay in both systems, and additional PEEP caused auto-cycling. A low inspiratory drive increased trigger delay in the pressure sensing system, while trigger delay was not affected in the flow sensing system. The Paw and Pdriv differentials were lower in flow triggering than in pressure triggering. CONCLUSIONS: With respect to triggering delay, the triggering capabilities of the pressure and flow sensing systems were comparable with and without PEEP and/or high airway resistance at the same sensitivity level, unless low inspiratory drive and air leak were present. In terms of pressure differentials, the flow triggering system may require less inspiratory effort to trigger the ventilator than that of the pressure triggering system with a comparable triggering time. However, this difference may be extremely small.

Lung↗
PubMed1996

Acute pathologic features with angiographic correlates of the nearly or completely occluded lesions of the cervical internal carotid artery.

BACKGROUND: The true pathologic process of nearly or completely occluded lesions of the cervical internal carotid artery (ICA) has not been studied sufficiently. This information is important in determining the critical indications for endarterectomy. METHODS: Acute pathologic features of these advanced occlusive lesions of the ICA were studied in 40 patients who underwent emergency carotid endarterectomy. Gross morphologic and histopathologic features of these occlusive lesions were examined, and the relationship between the clinical information and the pathologic characteristics was investigated. RESULTS: Thirty-seven lesions had histologic features of advanced atherosclerosis complicated by fresh intraplaque hemorrhages with or without transintimal extension. Thinwalled neovessels were thought to be an important etiologic factor in producing intraplaque hemorrhage. The remaining three lesions without these changes had strangulated embolic material at the occluded portion. A good correlation between these pathologic features and angiographic findings was found. CONCLUSION: The presented results clearly indicate that intraplaque hemorrhage is the most important factor in producing and determining the acute pathologic features of symptomatic and advanced atheromatous occlusive ICA lesions.

Acute Disease↗
PubMed1996

Metastatic masseter muscle tumour: a report of a case.

Both primary and metastatic malignancies of the masseter muscle are rare. We report a case of metastatic renal cell carcinoma to the masseter muscle. It was incidentally found as a hypervascular mass in carotid angiography for delineating a recurrent metastatic brain tumour. Prior to surgical removal, intravascular embolization via the left facial artery was performed in order to decrease intra-operative bleeding. The tumour was removed with minimum damage to the muscle fibres by the extraoral method, followed by a transient lower lip palsy. Metastatic intramuscular tumours, which are assumed to be due to haematogenous spread, are generally a sign of poor prognosis.

Angiography↗