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Biomedical subjects

S Murase

Publications and source records attributed to S Murase.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Depression symptoms among Chinese students in Japan].

The mental health of foreigners in Japan, which shows a prominent increase in number recently was studied. A major group of these foreigners are Korean and Chinese, as their countries and Japan historically had a close relationship. The Chinese population has shown large increases, quadrupling over a period of 10 years. This population is characterized by purpose of residence; with most of them visiting Japan to study. Using the Beck Depression Inventory (BDI) self rating scale, we examined depression symptoms among two groups of Chinese students studying in Japan; 71 students of Mie university (MU) and 90 students of Japanese language schools (JLS) in Mie prefecture. BDI examination revealed that 28.9% (mild; 22.2%, moderate; 3.3%, severe; 3.3%) of Chinese JLS students and 23.9% (mild; 22.5%, severe; 1.4%) of Chinese MU students were depressed. Chinese JLS students showed significantly higher total BDI scores than Chinese MU students (p < 0.05). BDI scores of item D (lack of satisfaction), J (crying spells) and S (weight loss) were also significantly elevated in Chinese JLS students (D: p < 0.01, J: p < 0.05, S: p < 0.01). These results suggest that Chinese JLS students experience more stress than Chinese MU students.

Adult↗
PubMed1995

Facilitation of the arterial baroreflex by the preoptic area in anaesthetized rats.

1. Activation of cell bodies in the ventrolateral part of the midbrain periaqueductal grey matter (PAG) facilitates the arterial baroreflex via the nucleus raphe magnus. The facilitatory effects of stimulation within the hypothalamus on the arterial baroreflex and their relation to the PAG and nucleus raphe magnus were studied in urethane- and chloralose-anaesthetized rats. 2. Systematic mapping experiments revealed that the preoptic area (POA) is the principal location in the hypothalamus of neuronal cell bodies that are responsible for the potentiation of the baroreflex. In addition to provoking hypotension and vagal bradycardia, both electrical and chemical stimulation of the POA produced facilitation of baroreflex vagal bradycardia (BVB) that was evoked by electrical stimulation of the aortic depressor nerve. Baroreflex hypotension was slightly augmented during activation of the POA in vagotomized rats. 3. Selective destruction of cell bodies either in the ventrolateral PAG or in the nucleus raphe magnus reduced facilitation of BVB by the POA. Hypotension and bradycardia due to POA stimulation were also markedly attenuated after such selective destruction. 4. In conclusion, the POA, the ventrolateral PAG and the nucleus raphe magnus constitute a functional complex that produces cardiovascular trophotropic effects including hypotension, vagal bradycardia and baroreflex facilitation.

Anesthesia↗
PubMed1995

'Aortic baroreceptor' neurons in the nucleus tractus solitarius in rats: convergence of cardiovascular inputs as revealed by heartbeat-locked activity.

Rat aortic depressor nerve (ADN) contains only baroreceptor afferents. We identified 'aortic baroreceptor' neurons in the nucleus tractus solitarius (NTS) as those responding to electrical stimulation of the ADN and attempted to demonstrate convergence of cardiovascular mechanoreceptor inputs in these 'baroreceptor' neurons. In chloralose-urethane-anesthetized rats, ADN stimulation evoked either short or long latency responses (SLR, LLR) in 193 neurons of the NTS. 28 (SLR, 15; LLR, 13) demonstrated ongoing activities with cardiac rhythm despite the fact that the ADN had been cut peripherally. In 12 (SLR, 5; LLR, 7) of the 28 neurons, heartbeat-locked activity was abolished by carotid occlusion (CO), and augmented by methoxamine-induced blood pressure elevation, indicating that the heartbeat-locked activity originated from carotid sinus baroreceptors (CSB). In 11 neurons (SLR, 6; LLR, 5), the heartbeat-locked activity was not affected by CO but was abolished by topical application of lidocain on the ipsilateral cervical vagus, suggesting that the heartbeat-locked activity originated mostly from cardiac mechanoreceptors. The origin of the heartbeat-locked activity of the remaining 5 neurons could not be determined. The onsets, as well as peaks of the heartbeat-locked activity of vagal origin appeared significantly earlier than those of CSB origin. In conclusion, NTS neurons receive converging projection not only from the two major arterial baroreceptors but also from the arterial baroreceptors and cardiac mechanoreceptors, thereby integrating sensory information of vascular and cardiac origins.

Animals↗
PubMed1995

Climbing fibre destruction triggers mossy fibre sprouting in adult rat cerebellum.

Molecular layers of the adult rat cerebellum, the inferior olivary neurones and climbing fibres which had been destroyed by 3-acetylpyridine (3-AP) and inferior cerebellar pedunculotomy, were examined using an antibody against corticotropin releasing factor (CRF) to visualize mossy fibres. Sprouting mossy fibres appeared in the molecular layer 2 days after 3-AP treatment. Morphologically, they showed no bundle formation, rosette-like swellings along their course, made ectopic synapses with interneurones, and had no association with arrested granule cells. The number of sprouting fibres gradually increased with time after 3-AP treatment. These findings indicate that mossy fibre sprouting is continuously induced in the climbing fibre-deficient cerebellum.

Afferent Pathways↗
PubMed1995

Effects of exposure to NO2 or SO2 on bronchopulmonary reaction induced by Candida albicans in guinea pigs.

The effects of NO2 or SO2 on the bronchopulmonary reactions induced by Candida albicans in guinea pigs were evaluated. Thirty-six guinea pigs (3 groups of 12 animals each) were sensitized with intraperitoneal injection of 10 mg of C. albicans, given twice. Two groups of animals were exposed to about 5 ppm of NO2 or SO2 for 4 h/d, 5 d/wk; this exposure was conducted a total of 30 times during the study. The third group served as the control and was not exposed to these pollutants. Two weeks after the second sensitization, all the animals were subjected to inhalation exposure to C. albicans. For 42 h after the antigen challenge, the respiratory rates and expiration/inspiration ratios of the animals were automatically monitored. The number of animals showing tachypnea was significantly higher in the NO2 exposure group than in the control from 15 h after antigen challenge. In the SO2 exposure group, the number of animals showing prolonged expiration or prolonged inspiration, or both, was significantly higher than that in the control group, and the symptoms were observed from approximately 15 h after antigen challenge. These findings showed that delayed-type dyspneic symptoms in guinea pigs were increased by exposure to NO2 or SO2, although the symptoms and degree of dyspnea were different for the two gases.

Administration, Inhalation↗
PubMed1995

Seasonal mood variation among Japanese residents of Stockholm.

Depressive symptoms estimated by the Beck Depression Inventory (BDI) were examined in winter and summer in a total of 242 Japanese adults staying less than 2 years or longer than 10 years in Stockholm, where the length of daylight changes dramatically throughout the winter and summer seasons. In spite of the difference in the period of residency, both groups of subjects showed more mental and somatic depressive symptoms in the winter than in the summer. Moreover, the winter BDI score of long stayers was significantly higher than that of short stayers. Accordingly, our results suggest that, although seasonal mood variation is essentially produced by a chronobiological factor, Swedish lifestyle to which long stayers have been accustomed also influences the seasonal mood variation.

Acclimatization↗
PubMed1995

[Trends of air pollution versus those of consultation rate and mortality rate for bronchial asthma in individuals aged 40 years and above in the Yokkaichi region].

We performed correlation analysis on the relationship between changes in air pollution and the consultation rate for bronchial asthma in the Yokkaichi region, taking effects of various socioeconomic factors into consideration. The effects of changes in air pollution on the mortality rate due to bronchial asthma were also evaluated. 1. Evaluation of annual changes in the simple correlation coefficient between the consultation rate and the concentration of each pollutant showed no significant correlation with a decrease in the air pollutant concentration in the age group less than 10 years old. However, in the middle-advanced male and female groups aged 40 years and above, the influence of past air pollution still remained. In addition, the partial correlation coefficients between the consultation rate for bronchial asthma and the degree of pollution, socioeconomic factors, and the rate of heavy smokers were calculated. A significant correlation was observed between the consultation rate for the females in each age group and the rate of patients receiving public assistance. 2. The mortality rate due to bronchial asthma in the polluted area increased rapidly with a time lag of several years after the peak of air pollution but decreased gradually thereafter. Presently, the mortality rate in the polluted area is similar to that in the non-polluted (control) area. 3. The mean age of death due to bronchial asthma was elevated because of a decrease in the deaths of those aged less than 60 years. As a result, the difference in the mean age of death due to bronchial asthma between the polluted area and the control area disappeared. With the recent remarkable alleviation of air pollution, the consultation rate and mortality rate due to bronchial asthma have decreased considerably. However, differences are still observed compared with the control area in some age levels so that continuation of monitoring of air pollution as well as consultation and mortality rates is considered necessary.

Adult↗
PubMed1995

[Treatment of facial arteriovenous malformation].

Arteriovenous malformations (AVMs) of the face are notoriously difficult lesions to manage because of the abundant vascular network in this region. We report three cases in which AVMs of the face were treated with endovascular embolization. Two cases with small AVM of the face and auricle were treated with direct puncture of the nidus and embolization with a small amount of n-butyl-cyanoacrylate (NBCA). In the third patient with a large AVM of the cheek, the external carotid artery (ECA) of which had been previously ligated surgically, percutaneous direct puncture of the ECA was performed. Superselective catheterization of each of the feeding arteries and embolization with a small amount of NBCA was then achieved. All cases demonstrated clinical and angiographical improvement. In two cases with a small AVM of the face and auricle, complete obstruction of the nidus was achieved. Direct puncture of the nidus and embolization with a small amount of NBCA was a safe and effective technique for the treatment of facial AVM.

Adult↗
PubMed1995

[Remission and recurrence of chronic obstructive lung disease in air pollution caused lung disease patients in the Yokkaichi area].

A study was conducted of patients covered by National Health Insurance (NHI) with chronic obstructive lung diseases legally-recognized as being caused by air pollution (Group A) and those not legally-recognized as air pollution caused (Group B) in the Yokkaichi area. Records of medical examinations (medical fee NHI statement), were examined, focusing on recurrence and remission. Over all incidence of recurrence after remission in asthmatic bronchitis and bronchial asthma conditions was 25% in Group A and 18% in Group B patients although with differences observed in different age groups. Approximately 50%-70% of the recurrence occurred within 3 years, and this incidence decreased approximately in proportion to time elapsed. Total remission rates for patients who had remission without recurrence and those who had remission after recurrence of bronchial asthma was approximately 39% in Group A and about 77% in Group B.

Adolescent↗
PubMed1995

Axonal elongation of grafted, embryonic inferior olivary neurons in the adult rat cerebellum and their synaptic formation on host Purkinje cells.

Although the brain grafting of adult mammals had failed to show reinnervation of host targets, embryonic neural tissue grafted to adult brains has been reported to establish new neuronal connections. However, the trajectories of growing axons of grafted neurons in the host brain are poorly understood. To study the morphological aspects of the trajectories of growing axons of grafted neurons in detail, ventromedial medulla containing the inferior olivary nucleus of 14-day rat embryos were grafted into the hemicerebella of 8-week-old adult rats whose inferior olivary neurons and climbing fibers were previously destroyed. The cerebellum and the inferior olivary complex of host rats were histologically examined 1-6 weeks after surgery. The heterotopically grafted neurons sent their axons into the white matter and the molecular layer of the host cerebellum. These growing fibers made plexus formation in the molecular layer, ending with axo-somatic and/or axo-dendritic synapses on host Purkinje cells whose afferent climbing fibers had been eliminated. These results show that the growth cones of growing axons arising from the grafted neuron can find and reach host targets along unusual pathways, and that some of the mature host Purkinje cells retain the ability to form synapses with newly developing axons from the grafted immature inferior olivary neuron.

Animals↗
PubMed1994

Facilitation of the arterial baroreflex by the ventrolateral part of the midbrain periaqueductal grey matter in rats.

1. The effects of stimulation of the ventrolateral part of the midbrain periaqueductal grey matter (PAG) on the arterial baroreflex were investigated in urethane-chloralose anaesthetized and artificially ventilated rats. 2. Both electrical and chemical stimulation of the ventrolateral PAG provoked hypotension, vagal bradycardia and marked facilitation of baroreflex vagal bradycardia (BVB), which was induced by stimulation of the aortic depressor nerve. The magnitude of ventrolateral PAG facilitation of BVB was 328 +/- 193% (n = 34) for electrical stimulation and 243 +/- 224% (n = 13) for chemical stimulation. Baroreflex hypotension was slightly augmented during either electrical or chemical stimulation of the ventrolateral PAG in vagotomized rats. 3. Stimulation of the nucleus raphe magnus (NRM) also provoked hypotension, vagal bradycardia and facilitation of BVB. The magnitude of BVB facilitation was 234 +/- 132% (n = 8) for electrical stimulation and 328 +/- 170% (n = 7) for chemical stimulation. After microinjection of kainic acid into the NRM region, baroreflex facilitation, as well as hypotension and vagal bradycardia, produced by ventrolateral PAG stimulation, was almost abolished. 4. In conclusion, the ventrolateral PAG, besides producing hypotension and bradycardia, facilitates arterial baroreflexes. These effects are exerted via the NRM, sharply contrasting with effects of the dorsal PAG.

Animals↗
PubMed1994

Pharmacokinetics and pharmacodynamics of serum glycerol in patients with brain edema: comparison of oral and intravenous administration.

To clarify the pharmacokinetics and effect of ICP reduction of glycerol administered orally, the serum concentration of glycerol was measured by the enzymatic method and ICP was measured by the subdural balloon method in severe head injured patients with brain edema and increased ICP. Sequential change of serum glycerol concentration and its relationship to the reduction of ICP were analyzed. The results showed that the pharmacokinetics of glycerol through oral administration were similar to that of intravenous glycerol administration and the changes of ICP were also similar to that of intravenous glycerol administration. We determined that glycerol can be administered either per oral or per venous to obtain the same results for treatment of brain edema with raised ICP.

Administration, Oral↗
PubMed1994

Baroreceptor inhibition of the locus coeruleus noradrenergic neurons.

The locus coeruleus is involved in the regulation of blood pressure. The present study was undertaken to address the question of how the blood pressure, in turn, changes the activity of the locus coeruleus neurons via the action of baroreceptors. In chloralose- and urethane-anesthetized rats, the central cut end of the aortic depressor nerve, which does not contain chemoreceptor afferents in this species, was stimulated electrically to excite baroreceptor afferents after bilateral vagotomy and sectioning of the carotid sinus nerve. Single train-pulse stimulation of the aortic depressor nerve provoked the inhibition of ongoing activity in 48% of locus coeruleus neurons tested, but 30% of them responded by excitation with subsequent inhibition. However, when the train-pulse stimulation was repeated with a frequency of 5 Hz, which is close to that of the heartbeat in the rat, all neurons were markedly inhibited. Another series of experiments was conducted in vagotomized and carotid sinus nerve-sectioned rats with intact aortic depressor nerves. When blood pressure was elevated by an intravenous injection of a pressor agent, methoxamine or angiotensin II, or by rapid blood loading, ongoing activities of all locus coeruleus neurons tested were suppressed. In contrast, intravenously injected nitroprusside, a depressor agent, increased the activity of locus coeruleus neurons. In rats with all nerves preserved, rapid blood loading markedly inhibited the activity of these neurons. Such inhibition was partially but significantly attenuated by bilateral sectioning of the aortic depressor nerves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Degeneration of locus coeruleus axons in stress-induced depression model.

Antidepressants such as desipramine induce axonal regeneration of brain noradrenergic neurons. This novel action of antidepressants suggests the involvement of degeneration or retraction of brain noradrenergic axons in the pathophysiology of clinical depression. The present study was designed to further confirm this view in an animal model of stress-induced depression. The depression model was produced by exposing rats to prolonged forced walking stress. To see if axonal degeneration of noradrenergic neurons occurred in the depression model, the density of noradrenergic axons in the cerebral cortex was assessed by three different methods, antidromic stimulation technique, retrograde tracing with horseradish peroxidase and immunohistochemical staining with dopamine-beta-hydroxylase antiserum. These methods all assured of degenerative changes of noradrenergic axon terminals in the depression model. Furthermore, it was found that repeated treatments of the depression-model rats with imipramine could cause regeneration of cortical noradrenergic axons. These findings support the view that degeneration or retraction of noradrenergic axons is involved in the pathophysiology of depression.

Animals↗
PubMed1994

[Vertebral artery injury following mild neck trauma: report of two cases].

Two cases of vertebral artery injury following mild neck trauma are reported. A 52-year-old man was hospitalized with gait disturbance 7 days after mild traffic accident. Right vertebral angiogram revealed complete occlusion of the rt. vertebral artery (VA) and MR images revealed infarction in the rt. cerebellar hemisphere and rt. dorsolateral part of the medulla oblongata and revealed the thrombus in the rt. VA. He underwent anticoagulation and became asymptomatic. Angiogram 6 months later revealed the vessel to be normal. A 23-year-old man who has a habit of self-manipulation of his neck was hospitalized on the day when he experienced dysesthesia in the left part of his face and left upper and lower extremities and unsteady gait. MR images revealed multiple infarction in bilateral cerebellar hemispheres and thrombus in bilateral VAs. Bilateral vertebral angiogram revealed severe stenoses of bilateral VAs. He underwent anticoagulation and wore soft collar. Angiogram 20 days after onset revealed improvement of bilateral VA stenoses. He was discharged with no neurological deficit. It is said that vertebral artery injuries in association with head and neck trauma are relatively rare, but this condition is possible to be more common than realized, considering that the case of unilateral VA occlusion or the case with well developed collateral circulation is sometimes well tolerated for ischemia and that this condition can occur even after mild head and neck injury. The diagnosis must be established by vertebral angiogram, but MRI and MRA are very useful as ancillary methods. The therapeutic point is to prevent propagation of the thrombus and distal embolism, accordingly wearing a collar and anticoagulation are important.

Adult↗
PubMed1993

Stabilization of alpha-helix in C-terminal fragments of neuropeptide Y.

To elucidate the alpha-helix-stabilizing effect of amino acids at the helical ends, we prepared analogs of C-terminal fragments of neuropeptide Y (NPY) containing an alpha-helical part. The helix-stabilizing tendency of N-terminal amino acid in NPY (12-36) was found to be as follows: Thr > Ser > Gly > Gln > Cys > Asn > Asp > Val > Phe > Glu > Lys > Tyr > Ala = Trp > His > Arg, suggesting the importance of end capping. The capping effect was not evident when N-termini in NPY (11-36) and NPY (13-36) were replaced. Under the same conditions as those for the receptor binding, [Thr12]NPY (12-36) had about 4-fold higher alpha-helix content than [Arg12]NPY (12-36). However, there was no apparent relationship between the helix content and binding affinity to the Y2 receptor.

Amino Acid Sequence↗