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M Kawaguchi

Publications and source records attributed to M Kawaguchi.

At least 19 recordsLinked to original sources
PubMed1999

Functional MR imaging with venography for neurosurgical identification of the central sulcus.

We evaluated the applicability of functional MR imaging overlaid onto brain images superimposed venography for neurosurgical identification of the central sulcus. In 20 volunteers and 12 patients with brain tumors located around the sensorimotor cortex, gradient echo and large flip angle functional MR image was performed to allow visualization of flow effect and susceptibility related changes in relative large vein by motor hand task. Functional MR image acquired was overlaid on 3D anatomical image with 3D venography. Based on the 3D mapping, intra-operative cortical somatosensory evoked potentials (SEPs) were recorded. The significant activation area obtained from functional MR imaging was projected on an ascending cortical vein in 16 volunteers (80%) and 10 patients (83%). Comparing the anatomical activation map with visual inspection of the exposed cortical surface made it easy to identify the activation area during surgery. The cortical veins in 9 of 10 were validated as a central vein by intra-operative cortical recording of SEPs. Combination of functional MR imaging overlaid onto 3D anatomical image with venography and intra-operative SEPs permitted rapid and accurate localization of the central sulcus during surgery.

Adult↗
PubMed1999

The effects of prostaglandin E1 on intraoperative temperature changes and the incidence of postoperative shivering during deliberate mild hypothermia for neurosurgical procedures.

UNLABELLED: We investigated the effects of i.v. prostaglandin E1 (PGE1) on intraoperative changes of core temperature and the incidence of postoperative shivering in neurosurgical patients undergoing deliberate mild hypothermia. Eighty-three patients were randomly assigned to one of three groups: patients in the control group did not receive PGE1, whereas patients in the PG20 group and PG50 group received PGE1 at a dose of 0.02 and 0.05 microg x kg(-1) x min(-1), respectively. The administration of PGE1 was started just after the induction of anesthesia and continued until the end of anesthesia. Anesthesia was maintained with nitrous oxide in oxygen, sevoflurane, and fentanyl. After the induction of anesthesia, patients were cooled using a water blanket and a convective device blanket. Tympanic membrane temperature was maintained at 34.5 degrees C. During surgical wound closure, patients were rewarmed. Intraoperative changes in tympanic membrane and skin temperatures and the incidence of postoperative shivering were compared among groups. Demographic and intraoperative variables were similar among groups. There were no significant differences in tympanic temperatures among groups at each point during the operation. Skin temperature 30 min after rewarming and just after tracheal extubation was significantly lower in the PG20 group than in the PG50 group. Postoperative shivering was more frequent in the PG20 group (43%) than in the control (13%) and PG50 (17%) groups. These results suggest that the intraoperative administration of PGE1 does not affect changes in core temperature during deliberate mild hypothermia and that PGE1 at a dose of 0.02 microg x kg(-1) x min(-1) may increase the occurrence of postoperative shivering. IMPLICATIONS: Deliberate mild hypothermia has been proposed as a means of providing cerebral protection during neurosurgical procedures. Vasodilating drugs may be used during deliberate mild hypothermia to maintain peripheral circulation and to enhance the cooling and rewarming rate. In the present study, however, we found no benefit from i.v. prostaglandin E1 administration during deliberate mild hypothermia in neurosurgical patients.

Alprostadil↗
PubMed1999

Antihypertensive effect of insulin via nitric oxide production in the Zucker diabetic fatty rat, an animal model for non-insulin-dependent diabetes mellitus.

It has been reported that insulin treatment improves hypertension in patients with diabetes mellitus. The mechanisms of the antihypertensive effect of insulin, however, remain to be fully elucidated. In the present study, we investigated a possible involvement of nitric oxide (NO) in insulin-induced reduction of blood pressure using the Zucker diabetic fatty (ZDF) rat, an animal model of non-insulin-dependent diabetes mellitus. The animals were divided into three groups and treated for 4 weeks with daily subcutaneous injections of insulin (25U/kg body weight) with or without oral administration of l-nitro-arginine methyl ester (L-NAME, 50mg/kg/day body weight as drinking water), an inhibitor of NO synthase (NOS). Saline solution was injected subcutaneously in the control groups. During the experimental period, body weight gain was greater in the insulin-treated groups than in the control groups whereas water intake was considerably decreased in the insulin-treated groups. Insulin treatment resulted in a decrease in plasma glucose and blood pressure, and an increase in both NO metabolites (NOx) in the plasma and NOS activity in the aorta tissue. L-NAME treatment blunted not only the antihypertensive effect of insulin but also the changes in NOx and NOS activity. These findings suggest that insulin reduces blood pressure in the ZDF rat by stimulating NOS activation and NO production.

Animals↗
PubMed1998

Insulin-induced hypoglycemia does not impair the surge of luteinizing hormone secretion in the proestrous rat.

To know whether insulin-induced hypoglycemia (IIH), which has been shown to inhibit pulsatile luteinizing hormone (LH) secretion, also affects the surge of LH secretion, adult female rats were injected with insulin (5 units/rat) or saline intravenously at 1300 or 1600 h on the day of proestrus and serum concentrations of LH and blood glucose were determined during the period from 1100 to 2100 h. The injection of insulin at neither 1300 nor 1600 h affected the surge of LH secretion, but it significantly decreased the blood glucose. Together with our recent hypothesis that the pulsatile and surge of LH secretion are controlled by separate gonadotropin-releasing hormone (GnRH) mechanisms, we conclude that the GnRH surge generator is less sensitive to IIH than the GnRH pulse generator.

Analysis of Variance↗
PubMed1998

Inhibitory regulation of amylase release in rat parotid acinar cells by benzodiazepine receptors.

This study examined the influence of benzodiazepine receptors on amylase release from rat parotid acinar cells. Diazepam (10(-8)-10(-6) M), which is a potent agonist of both central- and peripheral-type benzodiazepine receptors, dose dependently decreased amylase release induced by isoprenaline and carbachol, which are beta-adrenoceptor and muscarinic receptor agonists, respectively. The maximum inhibitory response was obtained with 10(-6) M diazepam: amylase release was decreased to 57% (isoprenaline) and 39% (carbachol) of maximal levels, while these responses were completely inhibited by propranolol and atropine, respectively. Clonazepam and 7-chloro-1,3-dihydro-1-methyl-5-p-chlorophenyl)-2H-1,4-benzodiazepine-2- one (Ro 5-4864), which are selective agonists of central- and peripheral-type benzodiazepine receptors, respectively, also produced a significant and dose-dependent decrease in isoprenaline-induced amylase release. The inhibitory potency was diazepam > clonazepam > Ro 5-4864. Flumazenil and 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide (PK 11195), which are selective antagonists of central- and peripheral-type benzodiazepine receptors, respectively, dose dependently blocked the inhibition of isoprenaline-induced amylase release by diazepam. At a concentration of 10(-5) M, flumazenil and PK 11195 restored amylase release to approximately 75% of that in the presence of isoprenaline alone. The combination of both antagonists completely prevented the inhibition by diazepam. Similarly, the inhibitory responses of clonazepam and Ro 5-4864 were completely blocked by flumazenil and PK 11195, respectively. These results suggest that, in rat parotid acinar cells, benzodiazepines inhibit beta-adrenoceptor and muscarinic receptor-stimulated amylase release and that both central- and peripheral-type benzodiazepine receptors contribute to this inhibitory regulation.

Adrenergic beta-Agonists↗
PubMed1998

Characterization of central- and peripheral-type benzodiazepine receptors in rat salivary glands.

Benzodiazepines have been shown to inhibit salivary secretion from the rat salivary gland. This action is mediated by specific benzodiazepine binding sites in the glands. The presence and characteristics of central- and peripheral-type benzodiazepine receptors in rat parotid and submandibular glands were examined employing [3H]Ro15-1788 and [3H]PK11195 as radioligands. [3H]Ro15-1788 and [3H]PK11195 bound with high affinity for both salivary glands ([3H]Ro15-1788: 24.5 and 37.4 mM, [3H]PK11195: 1.37 and 1.88 nM, for parotid and submandibular glands, respectively). [3H]Ro15-1788 binding sites occupied only 0.22 to 0.43% of the total binding for benzodiazepine receptors in the glands. The rank order of the competing potency of [3H]Ro15-1788 binding (Ro15-1788 = clonazepam > diazepam > flunitrazepam > PK11195 > Ro5-4864) and [3H]PK11195 binding (Ro5-4864 = PK11195 > diazepam = flunitrazepam > clonazepam) demonstrated that [3H]Ro15-1788 and [3H]PK11195 binding sites were characteristic of the central and peripheral type, respectively. These studies show that both central- and peripheral-type benzodiazepine receptors exist in rat parotid and submandibular glands.

Adrenal Glands↗
PubMed1998

Activation of interleukin-1beta-converting enzyme by nigericin is independent of apoptosis.

Interleukin-1beta-converting enzyme (ICE) is believed to be one of the key proteases involved in apoptosis. Since the precursor form of interleukin-1beta (pre-IL-1beta) is one of the well known substrates for ICE, and a potassium/proton ionophore, nigericin, enhances IL-1beta processing, the authors hypothesized that nigericin induces apoptosis through the activation of ICE. In a lipopolysaccharide (LPS)-stimulated and nigericin-treated human monocytic cell line, THP-1, apoptosis was induced, as assessed as to a decrease in cell size, chromatin condensation, exposure of phosphatidylserine and DNA fragmentation. Under exactly the same conditions, nigericin also induced IL-1beta processing in these cells, which was significantly inhibited by an ICE inhibitor, acetyl-Tyr-Val-Ala-Asp-CHO. On the contrary, treatment with this inhibitor at the same concentration did not inhibit nigericin-induced apoptosis, assessed as to the decrease in cell size, chromatin condensation and DNA fragmentation. Although apoptosis induced by nigericin was also observed for LPS-stimulated human peripheral blood mononuclear cells and a mouse T lymphoma cell line, EL-4, the ICE inhibitor did not inhibit the apoptosis in the cells. These results suggest that activated ICE is not involved in the apoptosis induced by nigericin. Since apopain activity was not augmented under the same conditions, neither ICE nor apopain may play any role in the nigericin-induced apoptosis.

Animals↗
PubMed1998

Primary cancer of the small intestine and mutational analysis of the K-ras and p53 genes.

A 69-year-old woman was admitted to Hokuso Shiroi Hospital because of recurrent pain in the lower right side of the abdomen. Small-intestinal cancer was strongly suspected after fluoroscopy of the small intestine. Laparotomy showed advanced cancer of the ileum, of complete annular constrictive type, 9.5 x 5cm in size. Histologically it was moderately differentiated tubular adenocarcinoma. Neither visceral nor nodal metastases were found, and the patient has been well for the 20 months since surgery. The strong resemblance between the epidemiological characteristics of small-intestinal cancers and colorectal cancers prompted us to investigate the carcinogenetic mechanisms at the molecular level. A point mutation at codon 12 of the K-ras gene was found, while no alterations were noted in the p53 gene, whose mutations are frequent in colon cancers. The carcinogenetic mechanisms of the small-intestinal cancer we experienced may thus differ from those of colon cancers.

Adenocarcinoma↗
PubMed1998

Long-term results of endarterectomy, anatomic bypass and extraanatomic bypass for aortoiliac occlusive disease.

Over the past 20 years, 214 patients in our hospital were operated on for aortoiliac occlusion, including an endarterectomy for 88 legs in 64 patients, an anatomic bypass for 178 legs in 105 patients, and an extraanatomic bypass for 51 legs in 45 patients. The extraanatomic group was older than the other two groups (70 years versus 64 years), and also showed a higher instance of critical ischemic symptoms than the other groups (49% versus 16%). The 10-year primary patency rate was 88% for an endarterectomy, 91% for an anatomic bypass, and 73% for an extraanatomic bypass. The 10-year survival rate was 71% for an endarterectomy, 49% for an anatomic bypass, and 24% for an extraanatomic bypass. The possible complications related to each surgical method included sexual dysfunction resulting from endarterectomy, and graft infection and anastomotic aneurysm in the prosthetic bypass. No ischemic symptoms in the donor limb were noted following an extraanatomic bypass. The selection of the appropriate surgical method for aortoiliac occlusion should thus be made after a careful review of the patient's general condition, the morphology of arterial occlusion, and the risk of possible complications for each type of surgery.

Adult↗
PubMed1998

Choroid plexus carcinoma in infants: report of two cases and review of the literature.

Choroid plexus carcinoma (CPC) is a rare malignant brain tumour which occurs predominantly in childhood. We present the cases of two infants with CPC. One, a 6-month-old boy with the tumour in the right lateral ventricle, who died of a postoperative intracranial haemorrhage and severe gastrointestinal bleeding, and the other, a 9-month-old boy with the tumour in the fourth ventricle, who has been well without recurrence for 12 months after total removal in combination with chemotherapy using cisplatin and VP-16 and local radiotherapy. In the 54 CPC cases in children under 2 years of age including our 2 cases in which the clinical results were described in the literature since 1983, tumour location (lateral ventricle, p = 0.0225), surgery (gross total resection, p = 0.0447), and chemotherapy (yes, p = 0.0010) were revealed to be significant positive prognostic factors by the univariate analysis using the log rank test, and surgery (gross total removal, p = 0.0259) and chemotherapy (yes, p = 0.0016) were independent, significant positive prognostic factors in the multivariate analysis using the Cox proportional hazard regression model. Although there is a risk in doing a statistical analysis of other people's reports, these results suggest that, at present, the gross total removal of the tumour with intensive chemotherapy is the best choice of initial treatment for young children with CPC, and that radiotherapy should be considered for patients after 24 months of age and/or should be performed locally.

Carcinoma↗
PubMed1998

Clinical applicability of functional magnetic resonance imaging and activation study with single photon emission computerized tomography for functional mapping.

The purpose of this study is to estimate the clinical applicability of functional magnetic resonance imaging (f-MRI) combined with the activation study using single photon emission computerized tomography (SPECT) with special reference to identification of primary sensorimotor area. Five healthy volunteers and 5 patients with brain tumors located around the sensorimotor cortex were studied by both f-MRI with gradient echo and SPECT with 99mTc-ethyl cysteinate dimer using split-dose and subtraction method. In f-MRI study, the significant activation of the sensorimotor area was observed in all subjects. Various concurrent activation regions such as supplementary motor (2 volunteers vs. 4 patients), premotor (1 vs. 2) and ipsilateral sensorimotor area (1 vs. 2) were also observed. In the cases with the activation of neighboring regions of sensorimotor area, it was difficult to identify the area in f-MRI. In SPECT study, the sensorimotor area was depicted as the most increased area in regional cerebral blood flow in eight cases, the characteristics of which were helpful to diagnose the area, while significant activation of the area with edema could not be detected in two patients. Consequently, the sensorimotor area was cross-validated with both the modalities. This study demonstrated that it would be valuable to use both techniques for the clinical assessment of the sensorimotor area.

Adult↗
PubMed1998

Mild hypothermia can attenuate nitroglycerin-induced vasodilation of pial arterioles in the cat.

UNLABELLED: The purpose of the present study was to investigate the effect of mild hypothermia on nitroglycerin-induced vasodilation of cerebral vessels. The cranial window technique, combined with microscopic video recording, was used in an experiment involving 26 cats anesthetized with isoflurane. Animals were randomly assigned to either a normothermic or a mildly hypothermic group (33 degrees C). We administered three different concentrations of nitroglycerin (10[-6], 10[-5], 10[-4] M) under the window and measured the diameter of small (< 100 microm) and large (100-200 microm) pial arterioles. In the normothermic group (n = 13), nitroglycerin produced a significant dilation of both small and large arterioles in a dose-dependent manner. In the hypothermic group (n = 13), a significant dilation of arterioles was observed only after topical application of nitroglycerin at a concentration of 10(-4) M. The percent increase in diameter of small and large arterioles was less in the hypothermic group than the normothermic group. Our in vivo study demonstrates that topically applied nitroglycerin produces a dose-dependent dilation of pial arterioles in normothermic cats anesthetized with isoflurane, but the reduction of temperature to 33 degrees C significantly attenuates nitroglycerin-induced vasodilation of pial arterioles. IMPLICATIONS: Although nitroglycerin may be used in hypothermic patients, the effect of mild hypothermia on nitroglycerin-induced vasodilation of cerebral vessels is unknown. In this study, we investigated the effects of nitroglycerin on pial arteriolar diameter in normothermic and hyperthermic cats. Hypothermia was found to attenuate nitroglycerin-induced vasodilation.

Animals↗
PubMed1998

Postoperative neurological deterioration following the revascularization surgery in children with moyamoya disease.

We describe four children with moyamoya disease who developed neurologic deterioration following revascularization surgery. In all cases, anesthesia was smoothly induced and the intraoperative course was uneventful. Emergence from anesthesia was prompt and no new neurological deficit was observed. However, the children suffered strokes on 2, 4, 5, and 10 days, postoperatively, respectively. Dehydration and crying were thought to be closely associated with the stroke in each case. This report suggests that attention should be paid during entire the perioperative period to avoid stroke in patients with moyamoya disease.

Brain↗
PubMed1998

A case of shock subsequent to treatment of intracranial hypertension by mannitol injection combined with hyperventilation.

This report describes a sudden decrease in blood pressure after conservative treatment of acute intracranial hypertension. A 63-year-old woman with acute hydrocephalus after undergoing clipping of an aneurysm of the right supracerebellar artery developed increased intracranial pressure, necessitating surgical management. On the operating table, the patient developed Cushing's reflex. Mannitol injection combined with hyperventilation was begun immediately to reduce her intracranial pressure. Fifteen minutes later, a sudden and prolonged suppression of circulation was observed (blood pressure 65/35-85/40 mmHg, heart rate 90-100 beats/min). Postoperatively, computed tomography of the head showed compression of the brain stem. We believe that this patient's blood pressure decrease was related to a sudden reduction of intracranial pressure and that mannitol injection was principally responsible for this occurrence.

Diuretics, Osmotic↗