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Biomedical subjects

C Miwa

Publications and source records attributed to C Miwa.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effects of entorhinal cortex lesion on learning behavior and on hippocampus in the rat.

The initial stage of Alzheimer's disease is characterized by a neuropathological change in the entorhinal cortex. In a previous study it was shown that rats with excitotoxic lesion of entorhinal cortex showed an impaired acquisition of passive and active avoidance responses. In this study a rat with excitotoxic lesion of the entorhinal cortex was tested for 'more operant' behavioral learning (i.e., positive reinforcement operant learning). The hippocampus was also examined histologically as acetylcholinesterase-stained sections, and as synaptophysin immunostained sections and examined biochemically by liquid chromatography. Eight weeks after operation, the bilateral entorhinal cortex lesioned rats showed an impaired acquisition of positive reinforcement operant learning. The lesioned side of unilateral entorhinal cortex lesioned rats showed a decrease of acetylcholinesterase-positive fibers in the CA3, the dentate gyrus, and of synaptophysin-positive substances in the CA3. Biochemical study showed a decreased level of acetylcholine in the CA3, and in the dentate gyrus. The histological and biochemical findings are interpreted as indicating that the entorhinal cortex of the rat provides the major extrinsic synaptic input to the hippocampal formation via the circuit which serves as a relay passage through the dentate gyrus and via direct projections into the hippocampus. Behavioral findings confirmed the importance of the entorhinal cortex in memory acquisition and indicated that rats with a partial neuronal loss in the entorhinal cortex may be a useful model for the memory disturbance of Alzheimer's disease.

Acetylcholine↗
PubMed1996

Spectral characteristics of heart rate and blood pressure variabilities during head-out water immersion.

To elucidate the roles of the autonomic nervous system in cardiovascular adaptation to microgravity, spectral analysis of heart rate and blood pressure variabilities were conducted during thermoneutral head-out water immersion in 8 healthy young subjects aged 23 to 31 years. In all subjects immersed up to the shoulder, the low-frequency (LF: 0.04-0.15 Hz) component in blood pressure variability and the ratio of LF power to high-frequency power (LF/HF ratio) in heart rate variability decreased, while the high-frequency (HF: 0.15-0.5 Hz) component of heart rate variability increased. Concomitantly, a decrease in heart rate was observed without significant changes in blood pressure during immersion. These results suggest that cardiac and vasomotor sympathetic nerve activities are suppressed and cardiac parasympathetic (vagal) nerve activity is activated during head-out water immersion.

Adult↗
PubMed1995

[Epidemiological study of the prognosis and relevant factors of demented patients].

One hundred twenty patients diagnosed as having dementia at the Center for Elderly Dementia in Hyogo College of Medicine, were recruited for this study to investigate the factors related to the prognosis of dementia. Patients were classified into the following two groups: those staying at home (group 1); those who died at home (group 2). The proportion of various dementias was almost equal in each group: vascular dementia, 30%; senile dementia of Alzheimer's type, 40%; mixed dementia, 20%; Alzheimer's disease, 10%. The average duration of disease in the two groups were not significantly different. The average age of onset in group 2 was higher than that in group 1. The rate of those with severe dementia was higher in group 2 than group 1. Those in group 2 scored less on the Mini-Mental State examination than those in group 1. Symptoms of dementia were assessed by the modified GBS-scale. In group 2, patients scored higher in impaired intellectual and motor functions. The CT findings suggested cortical atrophy, ventricular enlargement and periventricular lucency more often in group 2 than in group 1. Laboratory findings revealed that decrease in red blood cell count, hemoglobin, hematocrit and serum protein were more apparent in group 2 than group 1. It was considered that impaired motor functions, cortical atrophy, white matter lesions, anemia and malnutrition enhanced the probability of death. The study has confirmed that the prognosis of dementia is not only related to intellectual impairment but also deteriorated physical conditions such as motor dysfunction, anemia and malnutrition.

Aged↗
PubMed1994

Impairment in the acquisition of passive and active avoidance learning tasks due to bilateral entorhinal cortex lesions.

The relationship between the entorhinal cortex and learning behavior was examined. The initial stage of Alzheimer's disease has been shown to be characterized by neuropathological alteration in the entorhinal cortex, with the appearance of the greatest number of neuronal tangles and severe neuronal loss in comparison with other brain regions involved. This entorhinal cortex, because of its anatomical relationship to the hippocampus, may play a crucial role in memory formation. In this study, rats with bilateral ibotenic acid-induced lesions of the entorhinal cortices were tested for acquisition of passive and active avoidance learning tasks. These animals displayed no sensorimotor disturbances as shown by evaluation of locomotor activity and shock sensitivity. However, they did show impair acquisition of passive and active avoidance responses. On the other hand, when the lesions were induced after training, there was no extinction of the acquired passive and active avoidance responses. The results demonstrate the importance of the entorhinal cortex in learning acquisition and indicate that rats with partial neuronal loss in the entorhinal cortex may be a useful model for studying the memory disturbance of Alzheimer's disease.

Animals↗
PubMed1994

[Epidemic of aseptic meningitis with echovirus type 6 in Gifu Prefecture in 1992].

From January to December in 1992, an epidemic of aseptic meningitis occurred in Gifu Prefecture in children. Epidemiological, virological and serological investigations were performed. The results are as follows: 1) Cases involved ranged from 0 to 15 years of age, and 75.9% of them were in the 3 to 7 year of age group. 2) Six types of viruses were isolated from 73 of 108 cases (67.6%), and the Echovirus 6 was recovered from 68 cases (93.2%). 3) In 1992 by the cross neutralizing test between the prototype and isolated strains of Echovirus 6, a remarkable antigenic variation was not found. 4) In serological studies, the positive rates of neutralizing antibodies to Echovirus 6 in infant sera aged 0-9 years in 1992-1993, was 41.1%. The highest positive rates of antibodies was in the 5 year age group.

Adolescent↗
PubMed1994

[Epidemic of echo 11 virus infection in Gifu Prefecture in 1993].

An epidemic of Echo 11 virus infection occurred in Gifu Prefecture in children. Epidemiological and virological investigations were performed. The results are as follows: 1) Echo 11 viruses were isolated from patients from January to September. Most viruses were isolated in July. 2) Echo 11 viruses were isolated from all areas in Gifu Prefecture, especially from Seino and Hida areas. 3) Cases isolated Echovirus 11 ranged from 0 to 10 years of age, and 83.7% of them were in the 0 to 6 year of age group. 4) Five types of viruses were isolated from 51 of 86 cases (59.3%), and the Echovirus 11 was recovered from 43 cases (84.3%). 5) Echo 11 viruses were isolated from patients of various clinical conditions, but most patients in which isolated Echo 11 virus was isolated had aseptic meningitis, 17 cases (39.5%). Aseptic meningitis occurred in a higher frequency in those above 3 years of age. 6) By the cross neutralizing test between the prototype, isolated strain in 1982 and isolated strains in 1993 of Echovirus 11, a remarkable antigenic variation was not found in isolates in 1982 and 1993.

Child↗
PubMed1994

Human cardiovascular responses to a 60-min bath at 40 degrees C.

This study was designed to determine human cardiovascular responses to a 60-min bath at 40 degrees C compared with a thermoneutral bath at 34.5 degrees C. We measured mean blood pressure (MBP), heart rate (HR), skin blood flow (SBF) and core temperature in 8 healthy young males bathing at two different temperatures, 34.5 degrees C and 40 degrees C. During the thermoneutral bath (34.5 degrees C), heart rate tended to decrease, but all other variables showed no significant change. Ten min after entering the 40 degrees C bath, MBP decreased while HR and SBF increased. At the same time core temperature increased. We conclude that bathing at 40 degrees C may induce remarkable changes in the cardiovascular system by increasing core temperature when immersion in a hot bath for more than 10 min.

Adult↗
PubMed1993

Small, round-structured viruses (SRSVs) associated with acute gastroenteritis outbreaks in Gifu, Japan.

Two outbreaks of non-bacterial gastroenteritis occurred in Gifu prefecture in January 1989 and in January 1991. Both outbreaks were closely related to the consumption of raw oysters, and showed similar clinical features. Small, round-structured virus particles were found in patient stools in both outbreaks by electron microscopy. The role of these particles as the causative agents of the outbreaks were strongly suggested by immune electron microscopy and/or western-blotting immunoassay. When compared with SRSV-9 (Tokyo/SRSV/86-510) reported previously (Hayashi et al, J. Clin. Microbiol., 27: 1728-1733, 1989), it was found that these viral particles were antigenically similar to SRSV-9, and had a major structural protein of 63 kilodaltons (kDa). Further, the prevalence of this agent in Gifu area was examined by western blot antibody assay using 67 serum samples collected from the inhabitants in 1991. The results indicated the circulation of the same or antigenically similar agent in this area.

Adult↗
PubMed1993

[Epidemic of aseptic meningitis with echovirus type 30 in Gifu Prefecture].

During July to December in 1991, an epidemic of aseptic meningitis occurred in Gifu Prefecture in children. Epidemiological, virological and serological investigations were performed. The results are as follows: 1) Cases involved ranged from 0 to 13 years of age, and 75.9% of them were in the 3 to 7 year of age group. 2) Three types of enteroviruses were isolated from 83 of 133 cases (62.4%), and the echovirus type 30 was recovered from 71 cases (85.5%). 3) In 1991 with the cross neutralizing test between the prototype and isolated strains of echovirus type 30, a remarkable antigenic variation could not be found. 4) In serological studies, the positive rates of neutralizing antibodies to echovirus type 30 in infant sera aged 0-9 years in 1992-1993, was 51.9% with the prototype strain, but 34.0% with an isolated strain in 1991.

Adolescent↗
PubMed1993

Cardiovascular function in the elderly during water immersion.

In attempting to clarify the effects of aging on the regulatory functions of the cardiovascular system, we measured blood pressure, heart rate and stroke volume during thermoneutral head-out water immersion in seven healthy elderly and eight healthy young subjects. In the young subjects water immersion resulted in a marked increase in stroke volume, a deceleration of the heart rate and stable blood pressure values. In the elderly group the blood pressure increased significantly during shoulder-level water immersion. Compared to the young subjects, the elderly presented a less pronounced elevation of the stroke volume, and no change in the heart rate. These results indicate that the vasodepressive mechanisms regulated by baroreflexes diminish with aging, resulting in an elevation of blood pressure.

Adult↗
PubMed1990

[Diversity of etiological agent associated with aseptic meningitis--a survey on an epidemic in Tajimi City, Gifu Prefecture in 1984].

During the period from May to September in 1984, an epidemic of aseptic meningitis occurred in Tajimi city, Gifu prefecture. Virological and serological investigations were performed. Cases involved ranged from 0 to 12 years of age, and 83.1% of them were under 7 years of age. Four types of enteroviruses were isolated from 38 to 59 cases (64.4%), and virus type isolated were coxsackie B1 (15 cases), B4 (2 cases), B5 (4 cases), echovirus 16 (14 cases), a mixture of coxsackie-virus B4 and echovirus 16 (2 cases) and an unidentified strain (one cases). Virus types isolated from cerebrospinal fluid were coxsackievirus B1 and B5. In the serological studies of 47 paired sera of patients, a significant rise in titer against 4 virus types isolated was 29.8% with coxsackievirus B1, 12.8% with coxasackievirus B4, 17.0% with coxsackievirus B5, and 34.0% with echovirus 16. In relation between virus type isolated and a significant rise in titer of neutralizing antibody, almost all of the patients' sera (80.0%) exhibited a significant rise in titer of neutralizing antibody against one isolated virus type, but some patient's sera (20.0%) exhibited a significant rise against two or more of the viruses.

Child↗
PubMed1990

[Epidemic of infectious disease with echovirus type 16--epidemic in Tono area, Gifu Prefecture in 1984].

During the period from May to August, 1984, an epidemic of infectious disease with echovirus type 16 occurred in Tono area of southeast in Gifu prefecture. This virus caused children to have different clinical symptoms, one was a exanthem disease and another was aseptic meningitis. These cases confirmed by virological and serological methods were 48 cases, that is, patients with aseptic meningitis were 24 cases and patients with exanthem disease were 24 cases. By serological examination of antibody against echovirus type 16, it was confirmed that this virus type invaded Gifu Prefecture before 1984.

Adolescent↗
PubMed1990

[Epidemic of aseptic meningitis with echovirus type 18 in Gifu Prefecture in 1988].

On one hundred thirty seven cases with aseptic meningitis and 36 cases except aseptic meningitis in 1988, virological and serological investigations were performed. Cases with aseptic meningitis ranged from 0 to 15 years old age, and 90.5% of them were under 8 years of age. Seven types of enteroviruses and one unidentified strain were isolated from 58 of the 137 cases (42.3%), and echovirus type 18 was recovered from 46 cases (79.3%). Echovirus type 18 was isolated also from 16 cases with acute febrile illness and exanthem etc. With the cross neutralizing test between the prototype and isolated strains in 1988 of echovirus type 18, a slight antigenic variation could be found. In the serological studies in 1989, the positive rate of neutralizing antibody to echovirus type 18, was raised remarkably in children under 8 years old.

Adolescent↗
PubMed1989

[Epidemic of aseptic meningitis with echovirus type 7 in Gifu prefecture in 1986].

During the period from April to November in 1986, an epidemic of aseptic meningitis occurred in Gifu prefecture. Epidemiological, virological and serological investigations were performed. Cases involved ranged from 0 to 30 years of age, and 84.2% of them were under 7 years of age. Seven types of enteroviruses were isolated from 136 of 190 cases (71.6%), and echovirus type 7 was recovered from 121 cases (88.9%). With the cross neutralizing test between the prototype and isolated strains in 1986 of echovirus type 7, a remarkable antigenic variation could not be found. In the serological studies, the positive rates of neutralizing antibodies to echovirus type 7 in 1985, was lower than those in 1975. During the past 18 years before the 1986, echovirus type 7 was not isolated in Gifu prefecture, but in the serological studies, it was confirmed that the sporadic infection with echovirus type 7 had occurred in Gifu prefecture.

Adolescent↗
PubMed1980

Epidemic of hand, foot and mouth disease in Gifu Prefecture in 1978.

During the period from May to August, 1978, an epidemic of hand, foot and mouth disease (HFMD) occurred in Gifu prefecture. Epidemiological, virological and serological investigations were performed. Cases involved ranged from 0 to 31 years of age, and 80.2% of them were under 5 years of age. The incidence of HFMD with neurological complication (3.7%) was lower than that in 1973. Enterovirus 71 (EV71) was isolated from 83 of 108 cases (75.9%) and a significant rise in the neutralization antibody titer against the isolate was found in 14 of 25 cases (56%). Thus, it was confirmed that the causative agent of the epidemic of HFMD in Gifu prefecture in 1978 was enterovirus 71.

Adolescent↗