Biomedical subjects

S Kobayashi

Publications and source records attributed to S Kobayashi.

At least 37 records · Page 2Linked to original sources

PubMed2006

Ghrelin enhances glucose-induced insulin secretion in scheduled meal-fed sheep.

The purpose of this study was to investigate the effects of physiologic levels of ghrelin on insulin secretion and insulin sensitivity (glucose disposal) in scheduled fed-sheep, using the hyperglycemic clamp and hyperinsulinemic euglycemic clamp respectively. Twelve castrated Suffolk rams (69.8 +/- 0.6 kg) were conditioned to be fed alfalfa hay cubes (2% of body weight) once a day. Three hours after the feeding, synthetic ovine ghrelin was intravenously administered to the animals at a rate of 0.025 and 0.05 mug/kg body weight (BW) per min for 3 h. Concomitantly, the hyperglycemic clamp or the hyperinsulinemic euglycemic clamp was carried out. In the hyperglycemic clamp, a target glucose concentration was clamped at 100 mg/100 ml above the initial level. In the hyperinsulinemic euglycemic clamp, insulin was intravenously administered to the animals for 3 h at a rate of 2 mU/kg BW per min. Basal glucose concentrations (44+/- 1 mg/dl) were maintained by variably infusing 100 mg/dl glucose solution. In both clamps, plasma ghrelin concentrations were dose-dependently elevated and maintained at a constant level within the physiologic range. Ghrelin infusions induced a significant (ANOVA; P < 0.01) increase in plasma GH concentrations. In the hyperglycemic clamp, plasma insulin levels were increased by glucose infusion and were significantly (P < 0.05) greater in ghrelin-infused animals. In the hyperinsulinemic euglycemic clamp, glucose infusion rate, an index of insulin sensitivity, was not affected by ghrelin infusion. In conclusion, the present study has demonstrated for the first time that ghrelin enhances glucose-induced insulin secretion in the ruminant animal.

Animal Feed↗

PubMed2006

Imaging of cauda equina edema in lumbar canal stenosis by using gadolinium-enhanced MR imaging: experimental constriction injury.

BACKGROUND AND PURPOSE: It has been reported that disturbance of blood flow arising from circumferential compression of the cauda equina by surrounding tissue plays a major role in the appearance of neurogenic intermittent claudication (NIC) associated with lumbar spinal canal stenosis (LSCS). We created a model of LSCS to clarify the mechanism of enhancement within the cauda equina on gadolinium-enhanced MR images from patients with LSCS. METHODS: In 20 dogs, a lumbar laminectomy was performed by applying circumferential constriction to the cauda equina by using a silicon tube, to produce 30% stenosis of the circumferential diameter of the dural tube. After 1 and 3 weeks, gadolinium and Evans blue albumin were injected intravenously at the same time. The sections were used to investigate the status of the blood-nerve barrier function under a fluorescence microscope and we compared gadolinium-enhanced MR images with Evans blue albumin distribution in the nerve. The other sections were used for light and transmission electron microscopic study. RESULTS: In this model, histologic examination showed congestion and dilation in many of the intraradicular veins, as well as inflammatory cell infiltration. The intraradicular edema caused by venous congestion and Wallerian degeneration can also occur at sites that are not subject to mechanical compression. Enhanced MR imaging showed enhancement of the cauda equina at the stenosed region, demonstrating the presence of edema. CONCLUSION: Gadolinium-enhanced MR imaging may be a useful tool for the diagnosis of microcirculatory disorders of the cauda equina associated with LSCS.

Animals↗

PubMed2006

[Thoracoscopic repair of peritoneopleual communication with a giant diaphragmatic bullae in a patient with liver cirrhosis; report of a case].

Hepatic hydrothorax is defined as pleural effusion in patients with a cirrhotic liver. The pleural effusion occurs due to ascites flowing to the pleural cavity through a diaphragmatic communication. Recent literature has described the usefulness of a thoracoscopic repair and has shown that it can control pleural effusion very efficaciously. The patient was a 65-year-old woman who complained of dyspnea and was admitted to our hospital. A chest X-ray revealed marked right pleural effusion. We injected indigo carmine intraperitoneally and observed indigo carmine-colored pleural effusion; thus peritoneopleural communication was validated. After the failure of thoracic drainage and pleurodesis with minocycline hydrochloride, thoracoscopic surgery was performed 5 weeks after hospitalization. Obvious bulla formation was observed on the diaphragm, which was immediately resected with linear staplers. The postoperative course was excellent without any recurrence of pleural effusion.

Aged↗

PubMed2006

[Localized nodular pulmonary amyloidosis; report of a case].

A 66-year-old female was admitted to our hospital because of chest abnormal shadow. Chest X-ray and chest computed tomography (CT) on admission showed a nodule in the right middle lobe. The nodule was not diagnosed preoperatively by a bronchoscopy. She underwent partial lung resection including the nodule with video-assisted thoracoscopic surgery. The pathological diagnosis was amyloidosis, and we diagnosed her illness as localized nodular pulmonary amyloidosis, since the amyloid substance was type AL. In addition, electron microscopy showed amyloid as straightly fibrous materials in alveolus. It is difficult to differentiate amyloidosis from lung cancer by radiology, and the lung biopsy with video-assisted thoracoscopic surgery is useful and a safety way to establish diagnosis.

Aged↗

PubMed2005

Giant intracranial aneurysm of the anterior communicating artery treated by direct surgery using A3-A3 side-to-side anastomosis and A3-RA graft-STA anastomosis.

We describe a giant aneurysm of the anterior communicating artery (ACoA) which was treated with a STA-RA graft-A3 bonnet bypass and A3-A3 side-to-side anastomosis. A giant and partially thrombosed ACoA aneurysm was partially coated 3 years before his current presentation, its gradual increase producing visual field disturbances. An A3-A3 side-to-side anastomosis and STA-RA graft-A3 bonnet bypass were performed. The aneurysm was dissected, and the thrombus removed under transient parent-artery occlusion. The aneurysmal neck was successfully clipped without encountering ischemic changes. This strategy may be useful for treating giant or thrombosed aneurysms in the region of the ACoA.

Adult↗

PubMed2005

An origin for short gamma-ray bursts unassociated with current star formation.

Two short (< 2 s) gamma-ray bursts (GRBs) have recently been localized and fading afterglow counterparts detected. The combination of these two results left unclear the nature of the host galaxies of the bursts, because one was a star-forming dwarf, while the other was probably an elliptical galaxy. Here we report the X-ray localization of a short burst (GRB 050724) with unusual gamma-ray and X-ray properties. The X-ray afterglow lies off the centre of an elliptical galaxy at a redshift of z = 0.258 (ref. 5), coincident with the position determined by ground-based optical and radio observations. The low level of star formation typical for elliptical galaxies makes it unlikely that the burst originated in a supernova explosion. A supernova origin was also ruled out for GRB 050709 (refs 3, 31), even though that burst took place in a galaxy with current star formation. The isotropic energy for the short bursts is 2-3 orders of magnitude lower than that for the long bursts. Our results therefore suggest that an alternative source of bursts--the coalescence of binary systems of neutron stars or a neutron star-black hole pair--are the progenitors of short bursts.

Journal Article↗

PubMed2005

Cervical angina: a seemingly still neglected symptom of cervical spine disorder?

STUDY DESIGN: Retrospective, case series. DESIGN: A review of 10 surgical cases with symptoms of cervical angina. OBJECTIVE: To stress the importance of symptoms of cervical angina in patients with cervical spine disorders. SETTING: Fukui University Hospital, Japan. RESULTS: A total of 10 patients complaining of symptoms of cervical angina were admitted with a tentative diagnosis of coronary artery disease. Pain relief was achieved by anterior surgical decompression in all patients. CONCLUSION: We stress that physicians should be aware of the symptoms of cervical angina and that surgical intervention often leads to complete relief of symptoms.

Adult↗

PubMed2005

Cruciate paralysis and hemiplegia cruciata: report of three cases.

STUDY DESIGN: Report of three cases of cruciate paralysis and hemiplegia cruciata. OBJECTIVE: To stress the importance of upper cervical spine lesions causing neurological symptoms and signs. SETTING: Neuro-orthopedic service, Fukui University Hospital, Japan. RESULTS: Three patients (all females; one with congenital anomaly at the occiput-atlas level, one with assimilation of the atlas, and one with rheumatoid arthritis-related proliferative synovium) had clinical features of cruciate paralysis and hemiplegia cruciata. All three cases underwent decompressive surgeries. CONCLUSION: Neurological symptoms and signs of cruciate paralysis and hemiplegia cruciata should be carefully assessed, and surgical therapy should be based on the pathological condition.

Aged↗

PubMed2005

A short gamma-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225.

Gamma-ray bursts (GRBs) come in two classes: long (> 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z approximately 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core-collapse explosions of massive stars. In contrast, no short GRB had been accurately (< 10'') and rapidly (minutes) located. Here we report the detection of the X-ray afterglow from--and the localization of--the short burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.

Journal Article↗

PubMed2005

Intracisternal neurinoma of the C1 posterior root.

We report a rare intracisternal C1 posterior root neurinoma in a 35-year-old man without neurofibromatosis who presented with headache, nuchal pain, bilateral motor weakness of the upper extremities, and numbness in the right distal upper extremity. CT and MRI study showed a 20-mm intracisternal lesion at the foramen magnum. At surgery, there was an anastomosis between the C1 posterior root and a spinal accessory nerve at the site of the tumor; the root from the collateral sulcus of this C1 root was absent. Postoperatively, the patient remains free of symptoms. Foramen magnum neurinomas have been described as accessory nerve tumors. We present new anatomical consideration regarding this lesion.

Accessory Nerve↗

PubMed2005

An unexpectedly rapid decline in the X-ray afterglow emission of long gamma-ray bursts.

'Long' gamma-ray bursts (GRBs) are commonly accepted to originate in the explosion of particularly massive stars, which give rise to highly relativistic jets. Inhomogeneities in the expanding flow result in internal shock waves that are believed to produce the gamma-rays we see. As the jet travels further outward into the surrounding circumstellar medium, 'external' shocks create the afterglow emission seen in the X-ray, optical and radio bands. Here we report observations of the early phases of the X-ray emission of five GRBs. Their X-ray light curves are characterised by a surprisingly rapid fall-off for the first few hundred seconds, followed by a less rapid decline lasting several hours. This steep decline, together with detailed spectral properties of two particular bursts, shows that violent shock interactions take place in the early jet outflows.

Journal Article↗

PubMed2005

Bright x-ray flares in gamma-ray burst afterglows.

Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on the nearby environment and indirect information on the central engine that powers the burst. We report the discovery of two bright x-ray flares in GRB afterglows, including a giant flare comparable in total energy to the burst itself, each peaking minutes after the burst. These strong, rapid x-ray flares imply that the central engines of the bursts have long periods of activity, with strong internal shocks continuing for hundreds of seconds after the gamma-ray emission has ended.

Journal Article↗

PubMed2005

Transplantation of human neural stem cells for spinal cord injury in primates.

Recent studies have shown that delayed transplantation of neural stem/progenitor cells (NSPCs) into the injured spinal cord can promote functional recovery in adult rats. Preclinical studies using nonhuman primates, however, are necessary before NSPCs can be used in clinical trials to treat human patients with spinal cord injury (SCI). Cervical contusion SCIs were induced in 10 adult common marmosets using a stereotaxic device. Nine days after injury, in vitro-expanded human NSPCs were transplanted into the spinal cord of five randomly selected animals, and the other sham-operated control animals received culture medium alone. Motor functions were evaluated through measurements of bar grip power and spontaneous motor activity, and temporal changes in the intramedullary signals were monitored by magnetic resonance imaging. Eight weeks after transplantation, all animals were sacrificed. Histologic analysis revealed that the grafted human NSPCs survived and differentiated into neurons, astrocytes, and oligodendrocytes, and that the cavities were smaller than those in sham-operated control animals. The bar grip power and the spontaneous motor activity of the transplanted animals were significantly higher than those of sham-operated control animals. These findings show that NSPC transplantation was effective for SCI in primates and suggest that human NSPC transplantation could be a feasible treatment for human SCI.

Animals↗

PubMed2005

Management of severe subarachnoid hemorrhage; significance of assessment of both neurological and systemic insults at acute stage.

In order to elucidate mutual interrelationship between neurological and systemic dysfunctions in patients with subarachnoid hemorrhage (SAH) at acute stage, neurological condition, systemic complications and plasma catecholamine (CA) level were studied in 1431 consecutive cases admitted within 72 hours after the onset. Five hundred and twenty-four cases with Glasgow Coma Scale (GCS) score 8 or less were assigned to the group of severely ill cases (G-ill), 907 cases with GCS score 9 or more to that of the less ill group (G-well). Plasma CA level was extremely high at super-acute stage within an hour after bleeding and lowered fairly quickly within 24 hours to the normal range. Assuming the value obtained from a formula of [blood sugar level (mg/dl)/serum potassium concentration (mEq/L)] as stress index (SI), SI correlates well (r = 0.4-0.6) with serum catecholamine level at acute stage. Thus, sympathetic hyperactivity after SAH can be grossly estimated with SI. SI over 40 means that patients might have considerable neurological insults as well as systemic ones. For patients in G-well, SI over 50 means that there may be risks for systemic complications even in cases with good neurological condition.

Acute Disease↗

PubMed2005

Age-related decline of brain monoamines in mice is reversed to young level by Japanese herbal medicine.

Young (3-month-old) and aged mice (18-month-old) were fed a diet containing Japanese herbal medicine (TJ-41 or TJ-48) for 5 months, and the effect of the herbal medicines were examined in terms of levels of monoamines and their metabolites in the brain of young and aged mice. In the aged mice, the levels of norepinepherine, serotonin and their metabolites in the brain were decreased in the cortex, hippocampus and hypothalamus. Feeding of diet containing TJ-48, but not TJ-41, enhanced the levels of some monoamines and their metabolites in the brains of aged mice, comparable to those of young mice. The results indicated that the improvement of levels of monoamines by Japanese herbal medicine was observed only in the aged mice, not in the young mice. The data have suggested the importance of the aged animals to see the effect of medicine on the functions of organs or systems.

Aging↗

PubMed2005

Bile duct complications of hepatic arterial infusion chemotherapy evaluated by helical CT.

AIM: To describe the imaging findings of bile duct complications of hepatic arterial infusion chemotherapy (HAIC) using helical CT, to set diagnostic criteria, to develop a CT grading system, and to correlate these with clinical findings and laboratory data. METHODS: Follow-up helical CT of the abdomen was performed every 3 months for 60 patients receiving HAIC. Three radiologists reviewed all CT studies before and after treatment, using either the picture archiving and communication system or hard copies. The findings of bile duct abnormalities were correlated with findings from other imaging techniques, clinical symptoms and laboratory data. RESULTS: Bile duct abnormalities developed in 34 (57%) of cases either during HAIC or 1 to 12 months after treatment. In 14 (41%) of these 34 patients, enhancement of the hepatic parenchyma along the dilated bile duct or in the segmental or lobar distribution was observed. In 43 cases (72%), normal or abnormal alkaline phosphatase levels were consistent with normal or abnormal CT findings, respectively. Increasing alkaline phosphatase and bilirubin levels were related to CT grade. CONCLUSION: Imaging findings of bile duct complications of HAIC are similar to those of primary sclerosing cholangitis, and correlate well with abnormal clinical and laboratory data. In the presence of such clinical abnormalities, thin-section helical CT with careful review of the imaging studies helps to determine the correct diagnosis, monitor the changes and guide appropriate treatment.

Adenocarcinoma↗

PubMed2005

Localization and properties of respiratory neurons in the rostral pons of the newborn rat.

The distribution and discharge pattern of respiratory neurons in the 'pneumotaxic center' of the rostral pons in the rat has remained unknown. We performed optical recordings and whole-cell patch clamp recordings to clarify respiratory neuron activity in the rostral pons of a brainstem-spinal cord preparation from a newborn rat. Inspiratory nerve activity was recorded in the 4th cervical nerve and used as a trigger signal for optical recordings. Respiratory neuron activity was detected in the limited region of the rostral-lateral pons. The main active region was presumed to be primarily the Kölliker-Fuse nucleus. The location of respiratory neurons was further confirmed by Lucifer Yellow staining after conducting whole-cell recordings. From a membrane potential analysis of the respiratory neurons in the rostral pons, the respiratory neurons were divided into four types: inspiratory neuron (71.9%), pre-inspiratory neuron (5.3%), post-inspiratory neuron (19.3%), and expiratory neuron (3.5%). A noticeable difference between pontine and medullary respiratory neurons was that post-inspiratory neurons were more frequently encountered in the pons. Application of a mu-opioid agonist, [d-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin, transformed the burst pattern of post-inspiratory neurons into that of pre-inspiratory neurons. The electrical stimulation of the sensory root of the trigeminal nerve induced three types of responses in 85% of pontine respiratory neurons: inhibitory postsynaptic potentials (42.7%), excitatory postsynaptic potentials (37.7%) and no response (15.1%). Our findings provide the first evidence in the rat for the presence of respiratory neurons in the rostral pons, with localization in the lateral region approximately overlapping with the Kölliker-Fuse nucleus.

Animals↗

PubMed2005

Primary osteosarcoma of the thoracic spine: report of an unusual elderly patient with autopsy findings.

STUDY DESIGN: A case report of primary osteosarcoma of the spine in an elderly patient. OBJECTIVE: The histopathological features of osteosarcoma vary widely, often leading to diagnostic difficulties particularly when there is little evidence of osteoid formation. The report describes the difficulty in the diagnosis of osteosarcoma of the thoracic vertebra. SETTING: Department of Orthopaedics and Rehabilitation Medicine, Fukui University Faculty of Medicine, Fukui, Japan. METHOD: A 78-year-old man presented with paraparesis and underwent urgent anterior excision of a primary spinal tumor emanating from the T10 vertebra followed by artificial vertebral replacement. The patient eventually died of disseminated disease of vertebral osteosarcoma. RESULTS: Samples from the T10 vertebral tumor showed neoplastic growth of atypical spindle-shaped cells, with foci of storiform-like proliferation. The tissue also demonstrated positive immunohistochemical staining for vimentin and alpha-smooth muscle actin and a tentative diagnosis of leiomyosarcoma was made. However, a metastatic nodule of the chest wall at autopsy showed focal osteoid formation, a finding not seen in the primary tumor. CONCLUSION: Early detection and accurate diagnosis is important for improving not only patient prognosis but also the quality of life. We should always consider this rare entity, particularly in elderly patients who present with back pain and vertebral collapse.

Actins↗