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Biomedical subjects

M Kobari

Publications and source records attributed to M Kobari.

At least 109 records · Page 6Linked to original sources
PubMed1990

Cortical and subcortical hyperperfusion during migraine and cluster headache measured by Xe CT-CBF.

High-resolution, color-coded images of local cerebral blood flow (LCBF) were made utilizing stable xenon-enhanced computed tomography among patients with common migraine (n = 18), classic migraine (n = 12) and cluster headache (n = 5). During spontaneously occurring headache in common and classic migraine patients, LCBF values for cerebral cortex and subcortical gray and white matter were diffusely increased by 20-40% with the exception of the occipital lobes. LCBF increases involved both hemispheres whether the head pain was unilateral or bilateral. No significant differences were noted in the degree or pattern of LCBF increases during headaches of common and classic migraineurs. Similar cerebral hyperperfusion of greater magnitude was observed during cluster headaches but was more prominent on the side of the head pain. Present observations do not support the hypothesis of spreading cortical depression as a cause of classic migraine. From a hemodynamic viewpoint, LCBF increases during headaches of common or classic migraine or cluster appear similar. Evidence is adduced that sympathetic hypofunction with denervation hypersensitivity of cerebral vessels plays a role in the cerebral hyperperfusion of migraine headaches. More pronounced unilateral autonomic derangements appear to account for the symptoms and cerebral hyperperfusion associated with cluster headaches.

Adult↗
PubMed1990

Immuno-electron microscopic study of keratin distribution in the cochlea using monoclonal antibody.

Keratin distribution in the cochlea has been studied immuno-electron microscopically by both pre-embedding and postembedding methods. Keratin immunoreactivity in the guinea pig cochlea was clearly demonstrated in Hensen's cells, the reticular lamina surrounding both outer and inner hair cells, outer and inner pillar cells, Claudius' cells, inner and external sulcus cells, interdental cells of the spiral limbus, Reissner's membrane, border cells, inner phalangeal cells, Deiters' cells, and spiral prominence cells. Keratin expression at the ultrastructural level showed a nonfilamentous keratin system in the cytoplasm of cochlear supporting cells.

Animals↗
PubMed1990

[Effect of peripheral pancreatic duct obstruction on the progression of chronic pancreatitis].

Experimental chronic pancreatitis model were made in five dogs with chronic pancreatic fistula by injection of microspheres into peripheral pancreatic duct. Sequential changes of pancreatic exocrine and endocrine functions also with morphology were studied. Significant decrease of volume, bicarbonate output, and amylase output of pure pancreatic juice (PPJ) separately collected with stimulation of secretin were detected. While, viscosity of PPJ was significantly increased with concomitant increase of hexosamine concentration. Chronic pancreatitis was demonstrated morphologically also. These results suggest that concentrated PPJ caused by decrease in volume in PPJ and increase in viscosity of PPJ with concomitant increase in hexosamine concentration bring about the progression of chronic pancreatitis in this experimental model.

Amylases↗
PubMed1990

Potentiation of inner ear damage following electron beam irradiation with CDDP administration.

This study was designed to examine the combined ototoxic effects of cisplatin, an antitumor platinum compound, administration and electron beam irradiation on the inner ear of guinea pigs, histopathologically. One group received saline solution 4 ml/kg/day and the other group received cisplatin of 2 mg/4 ml/kg/day for five consecutive days. The right temporal bones of all animals of both groups were exposed to the electron beam of 14 Gy/day 3 hours after the daily injection of saline or cisplatin. All animals were sacrificed for inner ear histopathological findings 21 days after the last injection. A combination of cisplatin administration and electron beam irradiation produced a severe potentiation of the outer hair cell damage with no inner hair cell damage. Therefore, in treatment of head and neck carcinomas, it is important to pay attention to inner ear damage caused by combination therapy of cisplatin and electron beam irradiation which involves the inner ear.

Animals↗
PubMed1990

[Effect of continuous arterial infusion of protease inhibitor on experimental acute pancreatitis induced by closed duodenal loop obstruction].

The effectiveness of continuous arterial infusion of protease inhibitor on acute experimental pancreatitis was investigated. Acute hemorrhagic pancreatitis was induced by closed duodenal loop obstruction using mongrel dogs. The obstruction was released at 16 hr, and dogs were divided into three groups; Group I: non-treated control, Group II: nafamostat mesilate (FUT-175) was admitted intravenously (5 micrograms/kg/min), Group III: FUT-175 was admitted via celiac artery. At 24 hr, the concentration of FUT-175 in the pancreatic tissues in group II and III were 905 and 4453 ng/g, respectively. The trypsin like activities in the pancreatic tissues in group I, II and III were 2.1, 1.4 and 0.7 nmol/min/mg protein, and the extent of necrosis of pancreatic parenchyma in each group were 49.5, 25.6 and 12.4%, respectively. Serum calcium, amylase and lipase levels were significantly improved in group III. These results suggest that continuous arterial infusion of protease inhibitor markedly decreases the extent of pancreatic necrosis in severe acute pancreatitis.

Acute Disease↗
PubMed1990

[Effects of intragastric and intrajejunal ethanol administration on canine pancreatic exocrine secretion and duodenal pH].

The effect of ethanol on pancreatic exocrine secretion and intraduodenal pH was investigated in 3 dogs, after making pancreatic, gastric, and jejunal fistula. After intragastric and intrajejunal administration of ethanol the intraduodenal pH went down and pancreatic juice, pancreatic bicarbonate output was increased. The integrated value of pancreatic juice, pancreatic bicarbonate and pancreatic protein output was greater in case of intrajejunal administration rather than intragastric administration of the ethanol. After intragastric and intrajejunal administration of the ethanol the plasma concentration of CCK was unchanged. The decrease of intraduodenal pH and increase of pancreatic exocrine secretion was though be mainly due to the secondary action of gastric acid secretion stimulated by ethanol.

Animals↗
PubMed1990

Effect of glycerol on ischemic edema evaluated by somatosensory evoked potentials.

Glycerol is administered to reduce intracranial pressure by clinically enhancing cerebral edema. In this study, the effect of glycerol on ischemic edema was evaluated in 34 cerebral infarct patients by serial SEP. Evoked potentials were obtained by stimulating the hemiparetic median nerve 60 times with duration of 0.1 msec. N20 wave of SEP was analyzed by signal processor. SEP was monitored every 30 min for 3 hr after glycerol administration. Improvements of CCT, which means interpeak latency between N13 and N20, were observed in 14 patients. In seven patients, N20 waves were observed after IV administration of glycerol even though N20 waves were not observed before glycerol administration. The patients in acute stage or with the small infarction of basal ganglia showed these electrophysiological improvements. No CCT changes were observed in nine patients, and no N20 waves were obtained in two patients even after glycerol administration. In conclusion, electrophysiologically, glycerol effect on ischemic edema was well recognized in acute staged infarct patients and the patients with small infarction of basal ganglia.

Aged↗
PubMed1990

Effect of glycerol on the hemodynamics of acutely induced ischemic area in the cerebral cortex of cats.

The effect of glycerol on the hemodynamics of ischemic areas of the brain was examined. Employing a photoelectric apparatus, the CBV (vol%), mean transit time of blood(s), and CBF (ml/100 g/min) in the cortex of the left ectosylvian gyrus were determined in 16 anesthetized cats before, at 1 hr, and at 2 hr after left MCA occlusion. In 10 cats, 10% glycerol in 5% fructose saline was intravenously administered at a speed of 5 ml/kg/hr at 1 hr after MCA occlusion. The other animals served as the control. In the group given glycerol, the relation between the values of CBF at 1 hr after MCA occlusion (X) and those at 2 hr after MCA occlusion (Y) was curvilinear and could be expressed by the regression curve, Y = 0.04X2 - 0.26X + 7.68 (R2 = 0.86). In the control group without glycerol, however, a linear relation expressed by the equation, Y = 0.76X + 5.96 (R2 = 0.94), was obtained. Comparison between the two relations indicated that glycerol improved the hemodynamics in the mild ischemic area with a relatively higher CBF. Severely ischemic areas showed no improvement.

Animals↗
PubMed1989

Hyperperfusion of cerebral cortex, thalamus and basal ganglia during spontaneously occurring migraine headaches.

Color-coded, cross-sectional imaging of local cerebral blood flow (LCBF) was made in a prospective manner among 22 patients with well-established common or classic migraine utilizing the stable xenon-enhanced computed tomographic (Xe CT-CBF) method. LCBF in patients during spontaneously occurring headaches (N = 12) were significantly higher compared to patients without headache (N = 10) by 25-35%. The hyperperfusion involved not only cerebral cortex but also subcortical structures including thalamus, basal ganglia, and subcortical white matter. LCBF increases were not bilateral and sometimes asymmetrical, but LCBF increases were not consistently related to the preponderant side of headache. No significant differences were observed in the degree or pattern of cerebral hyperperfusion during headaches compared among common (N = 6) and classic (N = 6) migraineurs. Results suggest a common etiology for both common and classic migraine. Results are not consistent with spreading oligemia or spreading cortical depression as a cause of migraine. The cerebral hyperperfusion appears to be mediated by various neurogenic and chemical changes accompanying migraine. The unilateral nature of migraine head pain is more likely due to dilation of extracranial vessels.

Adult↗
PubMed1989

Effect of blood exchange transfusion as an initial treatment of acute hemorrhagic pancreatitis.

The effect of blood exchange transfusion on experimental acute pancreatitis was investigated. Acute hemorrhagic pancreatitis was induced in rats by the injection of sodium taurocholate into the pancreatic duct. One hour after the induction of pancreatitis, blood exchange transfusion was carried out in these rats. The survival rates by 24 hr significantly increased in the exchange transfusion group as compared to those in the non-treated control group. Blood exchange transfusion, though had not significant effect on the macroscopic findings at autopsy, reduced pulmonary edema. These results suggested that blood purification by exchange transfusion may be beneficial for patients with acute pancreatitis, especially at an early stage.

Amylases↗
PubMed1989

[Inhibitory effect of anti-platelet prostaglandin on liver metastasis of hamster pancreatic cancer].

Coagulation system and platelets play an important role in the stage of lodgement of tumor cells. We examined abilities of human and hamster pancreatic cancer cell lines to aggregate platelets in vitro, and investigated the effect of prostaglandin E1, I2, on artificial liver metastases of pancreatic cancer in Syrian golden hamster. Platelet aggregating activities were found in five out of six human pancreatic cancer cell line and thromboplastin likes activity in five cell lines. Diisopropanolnitrosamine induced hamster pancreatic cancer cells (HPK-1) were able to aggregate platelets both in vitro and in vivo and these activities were inhibited by prostaglandin I2. Hamster was inoculated intraportally with 1 X 10(6) HPK-1 cells. After two weeks autopsy of these hamsters revealed multiple metastatic nodules on liver surface. In this model we administered prostaglandin E1, I2 into the portal vein five minutes before cell inoculation. Number of liver surface nodules were significantly decreased to 33.1 + 7.0, 11.0 + 9.6 in hamster given 100g PGE1 PGI2 before cell inoculation, compared with control group of hamsters (62.0 + 6.6 PH9.3, 66.1 + 13.9 PH7.4). But administration of prostaglandin after cell injection was not effective. In all cases none of extrahepatic metastases were noted. Inhibitory action of PGE1 PGI2 on liver metastasis is suspected to be related to inhibition of platelet aggregation.

Alprostadil↗
PubMed1988

Colloid osmotic pressure of cat brain homogenate separated from autogenous CSF by a copper ferrocyanide membrane.

The colloid osmotic pressure (oncotic pressure) of cat brain homogenate against cerebrospinal fluid (CSF) was determined using an electronic osmometer with a rigid selectively permeable copper ferrocyanide membrane. First, the basic characteristics of the membrane were examined. The relative value of the reflexion coefficient (sigma) for polyethylene glycol (PEG) became rather stable above a molecular weight of 6000 Da, below which sigma declined. The osmometer showed a linear response to sucrose concentration, whereas it revealed a non-idealistic change with respect to concentration of high molecules (PEG). The temperature effect on sigma for albumin solution was found to be large. The membrane could thus be used for measuring the relative value of the colloid osmotic pressure of protein solutions without dilution and at the same temperature as the calibrating solution. Samples of CSF and brain cortex were freshly obtained from 5 cats. The cortex was immediately homogenized and the colloid osmotic pressure of the homogenate against the CSF was measured at room temperature within 3 min after cortex removal. The mean value was 213 +/- 11 (S.D.) mm Hg with the osmometer calibrated with respect to the colloid osmotic pressure of autogenous plasma.

Animals↗
PubMed1988

Imaging local cerebral blood flow by Xenon-enhanced computed tomography--technical optimization procedures.

Methods are described for non-invasive, computer-assisted serial scanning throughout the human brain during eight minutes of inhalation of 27%-30% Xenon gas in order to measure local cerebral blood flow (LCBF). Optimized Xenon-enhanced computed tomography (XeCT) was achieved by 5-second scanning at one-minute intervals utilizing a state-of-the-art CT scanner and rapid delivery of Xenon gas via a face mask. Values for local brain-blood partition coefficients (L lambda) measured in vivo were utilized to calculate LCBF values. Previous methods assumed L lambda values to be normal, introducing the risk of systematic errors, because L lambda values differ throughout normal brain and may be altered by disease. Color-coded maps of L lambda and LCBF values were formatted directly onto CT images for exact correlation of function with anatomic and pathologic observations (spatial resolution: 26.5 cubic mm). Results were compared among eight normal volunteers, aged between 50 and 88 years. Mean cortical gray matter blood flow was 46.3 +/- 7.7, for subcortical gray matter was 50.3 +/- 13.2 and for white matter was 18.8 +/- 3.2. Modern CT scanners provide stability, improved signal to noise ratio and minimal radiation scatter. Combining these advantages with rapid Xenon saturation of the blood provides correlations of L lambda and LCBF with images of normal and abnormal brain in a safe, useful and non-invasive manner.

Aged↗
PubMed1988

LCBF values decline while L lambda values increase during normal human aging measured by stable xenon-enhanced computed tomography.

Results of measurements of LCBF and L lambda values utilizing optimal CT-CBF methods under resting conditions are reported among thirty-two neurologically normal volunteers aged between 20 and 88 years. Measurements were made during inhalation of 26-30% stable xenon gas for 8 min and serial scanning utilizing a state-of the-art CT scanner with both eyes closed and ears unplugged. LCBF values for cortical gray matter were lowest in occipital cortex and highest in frontal cortex. Gray matter flow values were also high in subcortical structures with highest values measured in the thalamus. For white matter, highest flow values were measured in the internal capsule. Changes in LCBF and L lambda values were analyzed with respect to advancing age. Significant age-related declines in LCBF values were observed in occipital cortex and frontal white matter. Significant age-related increases in L lambda values were measured in frontal and temporal cortex, caudate nucleus and thalamus. Possible explanations are offered for these age-related increases in L lambda values for gray matter, such as accumulation of lipofuscin in neurons and relative compacting of gray matter with advancing age. The latter increases the numbers of nerve cells sampled per volume of gray matter measured.

Administration, Inhalation↗
PubMed1988

Comparison between the photoelectric method and H2 clearance method for measuring cerebrocortical blood flow in cats.

The photoelectric method using carbon black as a nondiffusible tracer of blood was compared with the hydrogen clearance (H2) method in nine anesthetized cats. A photoelectric apparatus and H2 electrode were applied to a small region of the cerebral cortex (left ectosylvian gyrus) for simultaneous measurement of the regional CBF. The values of CBF(H2) and CBF(photoelectric) were 50.7 +/- 19.2 and 52.1 +/- 14.5 ml.100 g-1.min-1, respectively. CBF(H2) and CBF(photoelectric) were found to correlate well (r = 0.588, p less than 0.01) when changes in CBF were induced by CO2 inhalation, exsanguination, hyperventilation, and occlusion of the middle cerebral artery. The correlation between CBF(H2) and CBF(photoelectric) was much better in the case of intraindividual comparisons (r = 0.957, p less than 0.01). In addition to its merits in common with the H2 clearance method, such as handiness, low cost, and strict regionality, the photoelectric method displayed the following advantages: time-to-time measurements of CBF (less than 20 s), immediate display of the microcirculatory flow pattern, and simultaneous monitoring of cerebral blood volume. However, measurements from deep structures of the brain are better performed by the H2 method despite the disadvantage of the use of a potentially explosive gas.

Animals↗
PubMed1988

Increase of plasma methionine-enkephalin levels in patients at the acute stage of cerebral infarction.

We investigated the participation of endogenous opioid peptide in cerebral ischaemia. In 13 patients with supratentorial infarction, the plasma immunoreactive methionine-enkephalin concentration at the acute stage (30.77 +/- 3.54 pg/ml) was significantly higher than that at the chronic stage (20.37 +/- 2.07 pg/ml) or that of the control subjects (19.64 +/- 1.71 pg/ml). However, it was unrelated to infarct size or patient severity. The increased methionine-enkephalin, which appears to originate from the sympatho-adrenal system or infarcted brain, may play a role in the evolution of cerebral ischaemia.

Aged↗