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Biomedical subjects

Y Handa

Publications and source records attributed to Y Handa.

At least 127 records · Page 7Linked to original sources
PubMed1990

Steroid and hyperosmotic diuretic effects on the early phase of experimental vasogenic oedema.

The effects of either dexamethasone or mannitol on the early phase of vasogenic oedema were studied by evaluating proton relaxation behaviour with in vitro NMR spectroscopy. Vasogenic cerebral oedema was induced by cold injury in cats. Significant (p less than 0.05) decreases in both longitudinal relaxation rate (R1 = 1/T1) and transverse relaxation rate (R2 = 1/T2) and increases in water content were observed in the white matter beneath the cold lesions four hours after injury. In the dexamethasone treated group, the decrease in R2 in the oedematous white matter was significantly (p less than 0.05) less than that in the non-treated control group and the mannitol group. The R2 in the oedematous white matter exhibited a two-component decay. The slow component of R2 in the dexamethasone-treated group was significantly (p less than 0.05) smaller than that in the control group. Our results indicated that dexamethasone has a prophylactic effect on the early phase of vasogenic oedema by preventing the accumulation of fluid in the extracellular space and that mannitol had no prophylactic effect on oedema formation.

Animals↗
PubMed1990

The distribution pattern of the sympathetic nerve fibers to the cerebral arterial system in rat as revealed by anterograde labeling with WGA-HRP.

To clarify the projection route and the expansion of the terminal plexus of the sympathetic nerve fibers innervating the cerebral arterial system in rat, we labeled the postganglionic fibers originating in the superior cervical ganglion and traced their entire course by anterograde labeling with wheat germ agglutinin-horseradish peroxidase. Sympathetic innervation of the internal cerebral artery by labeled fibers actually began just at the portion where it enters the intradural space, and innervated it up to the small pial arteries located in the subarachnoid space, but not the intracerebral arterioles. On the main arteries in the circle of Willis, bundles of nerve fibers ran parallel to the long axis of the vessels and branched perpendicularly their terminal twigs with regular intervals to form a rib-structure pattern. On the arterial branches derived from the circle of Willis, a fine nerve bundle and delicate terminal axons formed a meshwork instead of a rib-structure pattern. These observations confirmed the existence of differences in the distribution pattern of the nerve plexus, which strongly affects the strength and quality of vasoconstriction by sympathetic activation in each level of the cerebral arterial system.

Animals↗
PubMed1990

Appearance of retrogradely labeled neurons in the rat superior cervical ganglion after injection of wheat-germ agglutinin-horseradish peroxidase conjugate into the contralateral ganglion.

Injection of wheat-germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) into the superior cervical ganglion (SCG) of the rat results in accumulation of WGA-HRP in sympathetic postganglionic neurons in the contralateral SCG. The sympathetic pathways involved and the mechanism underlying the labeling were investigated. The labeling in neurons in the contralateral SCG was apparent 6 h after injection and increased in intensity with longer survival times. The number of labeled neurons reached 1300 at 72 h after the injection. Transection of the external (ECN) or internal carotid nerves (ICN) resulted in considerable reduction in the number of labeled neurons. Combined transection of both ECN and ICN virtually eliminated labeling in the contralateral SCG. This provides strong evidence that these two nerves are the major pathways for WGA-HRP transport out of the SCG. No labeling was observed in the contralateral SCG following injection of horseradish peroxidase (HRP). Therefore, it seems unlikely that a direct nerve connection exists between the bilateral ganglia. Instead, the labeling of contralateral SCG neurons appears to depend on the transneuronal transport capacity of WGA-HRP, which conveys the marker in an anterograde direction along the postganglionic fibers to terminals in sympathetic target organs, and then delivers it transneuronally to contralateral SCG neurons. We suggest that the sympathetic nerve fibers originating in the bilateral SCGs run intermingled and are in close contact in their peripheral target organs.

Animals↗
PubMed1990

Analyses of treadmill locomotion in adult spinal dogs.

The locomotion of the hindlimbs of two adult female spinal dogs, who were able to walk steadily on their hindlimbs 10 months after transection of the spinal cord (T10), and of two normal dogs was analyzed on a treadmill by means of high-speed cinematography and electromyography. With increase in walking speed, the duration of the step cycle was shortened by reduction of the duration of the stance phase, and the stride length was extended mainly by elongation of the transfer distance during the swing phase in both normal and spinal dogs. The patterns of muscle discharges of the hindlimbs in spinal dogs were similar to those in normal dogs. With increase in walking speed, reductions in the burst duration of the extensors were observed in both normal and spinal dogs. These results indicate that spinal dogs can adjust their locomotion speed in the same manner as normal dogs; this supports the theory that a central pattern generator regulating the locomotive activities of the hindlimbs exists in the spinal cord below the transection site.

Animals↗
PubMed1990

An infected congenital commissural lip fistula. Report of a case.

A case of infected congenital commissural lip fistula is presented. It appeared as a cheek swelling associated with inflammation due to infection. This case was treated with antibiotics and surgical drainage through the fistula. Our experience suggests that the possibility of infection of the fistula should be considered particularly in cases involved with angular stomatitis and/or scratching injury close to the commissure of the lips.

Adult↗
PubMed1990

Phosphorus-31 magnetic resonance spectroscopy of cerebral ischemia in cats.

The energy metabolism of the brain was measured in three types of ischemic models in the cat using phosphorus-31 magnetic resonance spectroscopy. The cerebral ischemia was produced as follows. In Group 1, two balloons were inflated in the left subclavian artery and the brachiocephalic trunk. In Group 2, the left middle cerebral artery was occluded through a transorbital approach. A combination of the two was employed in Group 3. Phosphorus-31 magnetic resonance spectra were obtained serially during 2 hours of ischemia. Immediately after occlusion, peaks of phosphocreatine and adenosine triphosphate decreased, whereas the peak of inorganic phosphate increased and split in two. Intracellular pH determined by chemical shift of the inorganic phosphate peak decreased. These changes were more pronounced in Group 3 when compared with the other groups. Histological study showed no infarction in Group 1 and infarcted areas in Groups 2 and 3. The size of the infarcted area in Group 3 was larger than that in Group 2. These results suggest that the model of middle cerebral artery occlusion potentiated with the occlusion of the brachiocephalic trunk and the left subclavian artery by balloon catheters is a reliable stroke model and that phosphorus-31 magnetic resonance spectroscopy is useful to understand the pathophysiological state of cerebral ischemia in vivo.

Animals↗
PubMed1990

Effect of endothelin on the canine basilar artery.

Endothelin, a recently discovered peptide produced by endothelial cells, has been shown to have potent constrictor effects on major arteries in vitro. This experiment was performed to determine whether endothelin plays a physiological role in cerebral vasospasm after subarachnoid hemorrhage. A cisternal injection of endothelin (10(-8) mol or 10(-9) mol) caused severe vasoconstriction of the canine basilar artery. The degree of vasoconstriction was dose related and long lasting, persisting for more than 24 hours. This constriction was prevented completely by pretreatment with nicardipine (10(-8) mol). Endothelin produced a marked and transient elevation in blood pressure and might play an important role in cerebral vasospasm. Further investigation will be needed to determine the role of endothelin in the pathogenesis of vasospasm.

Animals↗
PubMed1990

Analyses of airstepping movement in adult spinal dogs.

Airstepping of the hind limbs, which occurred when the adult chronic spinal dog was lifted up vertically, was analyzed by high-speed cinematography and electromyography (EMG). In the film analysis, the amplitude of the step increased with decreasing cycle period of the step. The time courses of changes in the joint angles of the hind limb throughout the step were not changed and the maximum flexion of each joint occurred in the knee, ankle and hip joint in that order at any cycle period. In the EMG analysis, alternating EMG activities of the ankle extensor and flexor, and also of the bilateral knee extensors appeared. The EMG burst durations of the knee and ankle extensors correlated closely with the cycle period of the step, although that of the ankle flexor was independent of changes of the cycle period. Since similar results were observed in analyses of treadmill locomotion in the normal and adult spinal dogs, it was thought that airstepping and treadmill locomotion were regulated by the same central pattern generator existing in the lower spinal cord.

Activity Cycles↗
PubMed1990

The effect of increased intracranial pressure during the appearance of pressure waves on the brainstem.

The effects of increased intracranial pressure (ICP) during the appearance of plateau waves or B-waves to the brainstem functions were investigated by evaluation of evoked potentials. The ICP and systemic blood pressure were continuously recorded in nine cases of intracranial hypertension. In the four cases demonstrating plateau waves in ICP recording, the latencies of the auditory brainstem evoked potentials (ABEP) measured during the appearance of plateau waves showed no significant differences compared to those measured during the interval phase between two plateau waves. In the five cases demonstrating B-waves in ICP recording, four cases showed significant (p less than 0.05) prolongation of the V wave of ABEP and three showed significant (p less than 0.05) prolongation of the P15 of somatosensory evoked potentials during the phase of increased ICP level with B-waves compared to those measured during the phase of decreased ICP level without B-waves, produced by external drainage of the cerebrospinal fluid or mannitol administration. The results indicated that during the appearance of plateau waves there were no significant changes of electrical activity in the brainstem, even though there was a significant reduction in cerebral perfusion pressure. It is suggested that in cases with the appearance of B-waves, an increase in ICP frequently affects the electrical activity in the brainstem.

Aged↗
PubMed1990

Intra-abdominal cyst following revision of ventriculoperitoneal shunt--case report.

An intra-abdominal cyst is a rare complication of ventriculoperitoneal (VP) shunt. A 19-year-old male was admitted complaining of abdominal pain and distension, dysuria, constipation, headache, and fever. He had undergone a VP shunt for obstructive hydrocephalus caused by a cerebellar astrocytoma 16 years earlier, and had received shunt revision twice, 5 years and 3 months earlier, respectively. Examination on admission revealed neck stiffness, early papilledema, a mass in the lower abdomen, and abdominal muscular guarding with rebound tenderness. Laboratory studies showed leukocytosis of the peripheral blood and pleocytosis of the cerebrospinal fluid (CSF). Abdominal ultrasonograms and computed tomographic scans demonstrated a cystic lesion. Under the diagnosis of meningitis and local peritonitis with an intra-abdominal cyst, we sistemically administered antibiotics and externalized the shunt. However, since the cyst fluid could not be aspirated through the abdominal catheter, it was exchanged with a flexible catheter under fluoroscopic control, according to Seldinger's method. A total of 400 ml of cyst fluid was drained. Staphylococcus epidermidis was detected in both the cyst fluid and the CSF. After meningitis subsided, repositioning of the abdominal catheter into the other side of the abdomen was performed but resulted in shunt malfunction and meningitis due to the same organisms. After meningitis again subsided, the VP shunt was converted to a ventriculoatrial shunt. The clinical course was uneventful thereafter.

Abdomen↗
PubMed1990

[Clinical and histological study of pituitary fibrosarcoma following radiotherapy for pituitary adenoma. Case report].

A 49-year-old male was admitted with a history of radiotherapy for a pituitary adenoma 9 years earlier. Three weeks prior to admission, he noticed visual loss in the left eye. Computed tomography (CT) scan revealed a sellar tumor. The patient underwent craniotomy and the tumor was partially resected. The histological diagnosis was benign pituitary adenoma. Two months after surgery, he began to complain of headache and left hemiparesis. CT scan at that time showed a large parasellar tumor extending into the right temporal lobe. A second craniotomy was performed and a firm tumor was partially removed. Under light microscopy, the tumor was composed of anaplastic spindle cells showing a fascicular pattern. Ultrastructurally, the tumor cells were spindle-shaped with elongated nuclei. The cytoplasm contained numerous distended rough endoplasmic reticula and free ribosomes, Golgi apparatus as well as glycogen granules. Some desmosome-like intercellular adherent were observed. Collagen fibers were scattered in the extracellular space. There was no apparent formation of a basement membrane. These findings suggested a close morphological similarity between tumor cells and fibroblasts, conforming to ultrastructural diagnostic criteria for fibrosarcoma. In spite of intensive treatment, such as a second radiotherapy and subsequent craniotomy, the patient died 9 months after admission. The clinical course and pathological findings of the post-irradiation pituitary fibrosarcoma are discussed.

Adenoma↗
PubMed1990

Role of adrenergic activity in ischemic brain edema.

Thirty male Wistar rats, weighing 200 to 300 g, were used for this study. During a 3- to 4-min period, 300 micrograms of 6-OHDA was injected stereotactically into the right lateral ventricle. The same amount of saline was injected into the ventricle for the control group. Seven days after this procedure, the right common carotid was occluded with a clip and 4 to 6 ml of blood was removed from the external jugular vein to reduce the blood pressure. The clip was removed in 2 hr, and blood flow was maintained for 1 hr. The SG of cerebral tissue was measured according to the method of Marmarou et al. The disruption of BBB was examined by Evans blue injection, and the brain tissue was also examined by electron microscopy. Rats with 6-OHDA treatment had brain edema although the control group had no edema. We suggest that the depletion of brain NA could cause a disturbance in cerebral microvascular tone and could make cerebral blood vessels more vulnerable to the decreased CBF when followed by restoration of the blood flow.

Animals↗
PubMed1990

Proton relaxation in acute and subacute ischemic brain edema.

The relation between regional ischemic brain edema and tissue proton relaxation rates (R1 = 1/T1; R2 = 1/T2) were studied in 16 macaque monkeys subjected to MCA occlusion. In vivo R2 measurements were obtained from multiple spin-echo (eight echoes) images taken at 2-, 3-, 4-, and 72-hr postischemia. In vitro R1 and R2 values were determined for corresponding regions after sacrifice at 4 hr (n = 8) or at 72-hr postischemia in seven surviving animals. The water content of the white and gray matter tissue samples was measured by the wet/dry method. Four animals (25%) showed ipsilateral regions of increased signal intensity as early as 2 hr after MCA occlusion. All seven animals imaged at 72 hr displayed such regions. Despite the absence of measured changes in tissue water content, significant decreases in R2, but not in R1, occurred at 4 hr. At this stage, R2 values correlated more closely than R1 with individual variations in water content. At 72 hr, marked decreases in both R1 and R2 were measured in ischemic deep gray matter and white matter. Cortical gray matter was unchanged. In edematous gray and white matter, both R1 and R2 correlated closely with tissue water content, but R2 was consistently 10 to 20 times more sensitive than R1. Biexponential R2 decay was observed at 4 and 72 hr, but only in the white matter region that became severely edematous at 72 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1990

[An aged woman with minimal change nephrotic syndrome complicated with reversible acute renal failure].

Reported was an aged woman (80-year-old) of minimal change nephrotic syndrome which was complicated with reversible oliguric acute renal failure. The patient presented massive proteinuria, anasarca, and severe azotemia. She recovered conservatively from the acute renal failure and subsequently remitted from the nephrotic syndrome after the treatment which comprised albumin infusion, diuretics, adrenocorticosteroid hormones (including the pulse therapy), antiplatelet drug, and anticoagulants. The histopathologic findings of renal biopsy were compatible with minor glomerular abnormalities and acute tubular necrosis with many tubular casts. The previously reported cases older than 80-year-old which remitted from minimal change nephrotic syndrome complicated with reversible acute renal failure, were very rare. The present case was the second case among the literatures.

Acute Kidney Injury↗
PubMed1990

[A case of progressive systemic sclerosis associated with a hemorrhagic infarction of the cerebellum].

Central nervous system is rarely involved in progressive systemic sclerosis (PSS) unless there are concomitant abnormalities in renal or lung function or hypertension. A 72-year-old woman with typical PSS developed cerebellar bleeding. Medical history records revealed, she had noted the onset of Raynaud's sign on her upper extremities at the age of 37. This was followed by necrosis and repeated infection, and as a result, shortening of her fingers in her 40's. The disease progressed and involved lower extremities, and then face and body in her 50's. Aortic valve stenosis was diagnosed at 69 year old, cardiac myopathy at 70 and at the age of 71 infectious dermatitis in both inguinal regions. Mild anemia, hypoalbuminemia and the decrease of serum Fe were discovered in June 1988. At the same time, prolonged ESR, positive C-reactive protein, RA, and anti-nuclear-antibody were also noticed. A chest roentgenogram revealed pulmonary fibrosis. Systemic hypertension was not noticed on the clinical course. She developed an onset of vertigo and vomiting in the morning of August 8, 1988. Consequently, she was brought to our hospital. She was alert but a physical examination showed a swallowing disturbance, dysarthria, right cerebellar ataxia, nystagmus and hypertension (192/100 mmHg). A CT examination on admission revealed a slightly low density area in right cerebellar hemisphere without mass effect. She was treated with dextran and mannitol and her condition improved on the 6th day of her admission. She was alert and blood pressure calm down to 120/70 mmHg without the use of anti-hypertension drugs on August 21.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Magnetic resonance imaging of embolism from intracranial aneurysms.

Two patients with embolism from unruptured intracranial aneurysms are reported. These patients experienced cerebral ischemic attacks at the ages of 10 and 64 years, respectively. Angiography revealed normal extracranial vessels and middle cerebral artery aneurysms. Preoperative magnetic resonance imaging showed intraaneurysmal clots and cerebral infarcts distal to the aneurysms. Aneurysmal neck clipping was carried out on the young patient. In the other case, the aneurysmal sac was excised, the intraluminal clot was removed, and the neck was closed with nylon sutures. These are the first cases of embolism from unruptured aneurysms in which magnetic resonance imaging revealed intraaneurysmal clots and cerebral infarcts distal to the aneurysms.

Aged↗
PubMed1989

A modification of the sagittal splitting technique ensuring that the osteotomy split lies immediately medial to the lateral cortex.

A modification of Obwegeser's sagittal splitting method for the correction of mandibular prognathism has been developed. The anterior border of the proximal segment is partially removed at the beginning of osteotomy, which is carried out on the immediate inner surface of the lateral cortex. This osteotomy plane just under the lateral cortex, obtained by the use of a thin, disposable reciprocating sawblade, contributed to a lower incidence of postoperative lower lip hypaesthesia in the 14 cases presented.

Bone Marrow↗