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Biomedical subjects

Y Mimori

Publications and source records attributed to Y Mimori.

47 records · Page 3Linked to original sources
PubMed1984

Regional and subcellular distribution of cyanide metabolizing enzymes in the central nervous system.

Activities of cyanide metabolizing enzymes were measured in various subcellular fractions and regions in the central nervous system. Brain rhodanese and liver beta-mercaptopyruvate sulfurtransferase showed a slight decrease in activity after death. The activity of beta-mercaptopyruvate sulfurtransferase was negligible in the rat brain, compared with that of rhodanese. A small amount of thiocyanate was produced from cyanide and beta-mercaptopyruvate in the human brain, probably due to contamination with red blood cells. Rhodanese activity was widely distributed in all the areas of nervous tissue examined. In the rat the olfactory bulb showed the highest rhodanese activity, and high activity was also observed served in the thalamus, septum, hippocampus, and dorsal part of the midbrain. Rhodanese activity was low in various parts of the cerebral cortex. The distribution pattern of rhodanese in post-mortem human brain was essentially similar to that in rat brain. The thalamus, amygdala, centrum semiovale, colliculus superior, and cerebellar cortex showed high rhodanese activity in the human brain. Rhodanese activity was detected in the spinal cord. Anterior horn showed the highest rhodanese activity in the cervical, thoracic, and lumbar cord. Most rhodanese activity in the rat brain was recovered in the mitochondrial fraction with the highest specific activity. Rhodanese activity was lower in spinal cords obtained from autopsied cases with amyotrophic lateral sclerosis than in those of control subjects. A significant decrease in rhodanese was observed in the posterior column of the cervical or thoracic cord, but the activity in the anterior horn did not differ significantly between the two groups.

Animals↗
PubMed1984

Regional and subcellular distribution in mammalian brain of the enzymes producing adenosine.

The activities of 5'-nucleotidase, 2'-nucleotidase, alkaline phosphatase, and acid phosphatase were measured in rat and autopsied human brains. The four phosphatases in the rat brain showed little change in activity after death. The activities of adenosine-producing enzymes were compared in various parts of rat and human brains. When phosphatase activity was measured at pH 7.5, 5'-nucleotidase showed the highest activity in the most parts of the brain. The activity of 2'-nucleotidase and that of nonspecific phosphatase were almost the same at pH 7.5. However, higher phosphatase activity was observed in all parts of the brain when nonspecific phosphatase activity was measured at pH 10.0 or 5.5. High specific activity of 5'-nucleotidase in the brain was detected in the membranous components, especially in the synaptic membranes. The activity of 2'-nucleotidase was distributed in the soluble and synaptosomal fractions. The highest activity of both alkaline and acid phosphatases was recovered in the crude mitochondrial fraction, with the highest specific activity in the microsomal fraction. Phosphatase activity was distributed widely in the rat brain. The activity of 5'-nucleotidase was high in the medulla oblongata, thalamus, and hippocampus, but low in the peripheral nerve, spinal cord, and occipital lobe. The activity of 2'-nucleotidase was high in the vermis and frontal lobe. The highest acid and alkaline phosphatase activities were detected in the frontal lobe and in the olfactory bulb, respectively. The distribution of the four phosphatases in the autopsied human brain was similar to that in the rat brain. The highest 5'-nucleotidase activity was observed in the temporal lobe and thalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

5'-Nucleotidase↗
PubMedDate not supplied

The P300 event-related potentials in dementia of the Alzheimer type. Correlations between P300 and monoamine metabolites.

We studied auditory event-related potentials (ERPs) in 40 patients with dementia of the Alzheimer type (DAT). Peak latencies and amplitudes of N100, P200 and P300 components were measured. To study the possible relationships between the ERPs and monoaminergic neurotransmitter functions, CSF neurotransmitter metabolites were also analyzed. In patients with DAT, the P300 amplitude was significantly reduced and the P300 latency was prolonged. CSF concentrations of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) were decreased. The P300 amplitude was significantly correlated with the 5-HIAA concentration. There were no correlations between the P300 components and the HVA concentration. These findings suggest that the serotonergic system modulates the P300 component of ERPs in patients with DAT.

Adult↗
PubMedDate not supplied

Age-related change in peripheral nerve conduction: compound muscle action potential duration and dispersion.

BACKGROUND: We investigated the effect of age on nerve conduction parameters with special reference to the compound muscle action potential (CMAP) duration and duration ratio. METHOD: We examined 295 subjects (aged 15-85 years old) with no previous history or present signs of peripheral neuropathy. The subjects were divided into 3 groups: young (15-34 years old); intermediate (35-64 years old), and old (65-85 years old). RESULTS: CMAP amplitude was lower in the old group than in the young group; however, the CMAP ratio (proximal CMAP/distal CMAP) did not change with age. The CMAP duration and duration ratio did not differ among the 3 groups. The CMAP area was smaller in the old group, but the area ratio was almost constant among the 3 groups. CONCLUSION: We suggest that age-related changes in CMAP amplitude, duration or area may occur uniformly, at least in the forearm and the calf segment, in routine nerve conduction studies. The present findings also provide useful and reliable information, regardless of age, in diagnosing peripheral neuropathy.

Action Potentials↗
PubMedDate not supplied

Dementia as a predictor of functional disability: a four-year follow-up study.

BACKGROUND: Prospective studies have shown that cognitive impairment is a strong and consistent risk factor of physical disability. However, cognitive impairment has been based on the result of a single screening tool. OBJECTIVE: To investigate the role of cognition in the subsequent incidence and decline of functional disability in basic activities of daily living (ADL) and instrumental activities of daily living (IADL) after a full assessment of dementia. METHODS: A group of 1,358 Japanese atomic bomb survivors aged 61 years or older who lived in the community or in institutions in Hiroshima City were followed for 4 years. During the baseline survey (1993-1995), subjects were administered a screening test for cognitive impairment. Those suspected of dementia underwent a series of cognitive tests (Hasegawa's dementia scale, Clinical Dementia Rating) and a neurological examination. The diagnosis of dementia was made according to DSM-III-R criteria. Study subjects were questioned about their reported ADL and their IADL. During the follow-up period, deaths were recorded and a follow-up survey (1997-1999) used to assess ADL and IADL performance. RESULTS: Dementia, even after adjustment for age, sex and history of stroke, was a strong predictor of functional disability, as indicated by ADL (odds ratio, OR = 14.0; confidence interval, CI = 5.4-36.3), IADL (OR = 10.1, CI = 2.2-46.4), and also by assessment of decline in ADL (OR = 9.8, CI = 4.2-22.8) or IADL status (OR = 3.9, CI = 1.8-8.3). CONCLUSION: Dementia is an important determinant of functional status. Deterioration in ADL is more significant than deterioration in IADL, suggesting that factors other than cognition, such as motivation or perceptual, sensory and motor abilities, may be important in IADL performance. This study confirms previous findings on risk factors that affect functional ability and extends our knowledge by examining several criteria of function that are important in the daily lives of elderly people.

Activities of Daily Living↗
PubMedDate not supplied

[Age-related changes in amplitude ratio, duration ratio and area ratio in nerve conduction studies].

We investigated the effect of aging on nerve conduction parameters in 184 subjects (aged 10-75 years) without any history or signs of peripheral neuropathy, in order to clarify the diagnostic parameters of demyelinating neuropathies in the aged. The CMAP amplitude ratio (proximal CMAP/distal CMAP), duration ratio and area ratio remained unchanged throughout the second to eighth decades. The lower limits of normal CMAP amplitude ratio (mean -3SD) were 0.79 (median nerve), 0.74 (ulnar nerve), 0.59 (peroneal nerve), and 0.48 (tibial nerve). The upper limits of normal CMAP duration ratio (mean 11+ 3SD) were 1.22 (median nerve), 1.19 (ulnar nerve), 1.35 (peroneal nerve), and 1.32 (tibial nerve). The lower limits of normal CMAP area ratio (mean -3SD) were 0.84 (median nerve), 0.78 (ulnar nerve), 0.61 (peroneal nerve), and 0.62 (tibial nerve). There were no age-related changes in amplitude ratio or duration ratio of SNAP, although the standard deviations increased with age. Since the amplitude ratio, duration ratio and area ratio are simple and age-independent, they can provide useful and reliable information for routine nerve conduction studies for aged patients with demyelinating neuropathies.

Action Potentials↗
PubMedDate not supplied

Ratios of nerve conduction parameters in proximal to distal limbs remain constant through the second to the eighth decades.

We investigated the effect of age on nerve conduction parameters to establish a diagnostic validity in demyelinating neuropathies of the aged. We evaluated 257 subjects (age 10-76 years old) with no history or signs of peripheral neuropathies. The CMAP amplitude ratio (proximal CMAP/distal CMAP), duration ratio, and area ratio were almost the same throughout the second to eighth decades. The respective lower limits of the normal CMAP amplitude ratio (mean-3 SD) were 0.79 (median nerve), 0.75 (ulnar nerve), 0.57 (peroneal nerve), and 0.45 (tibial nerve). The upper limits of the normal CMAP duration ratio (mean +3 SD) were 1.21 (median nerve), 1.22 (ulnar nerve), 1.37 (peroneal nerve), and 1.35 (tibial nerve). The lower limits of the normal CMAP area ratio (mean-3 SD) were 0.81 (median nerve), 0.78 (ulnar nerve), 0.60 (peroneal nerve), and 0.57 (tibial nerve). No age-related changes were observed in the amplitude ratio or duration ratio SNAP, although the standard deviation increased with age. Since the amplitude, duration and area ratios are easily calculated and age-independent, they can provide useful and reliable information on aged patients with demyelinating neuropathies by conventional nerve conduction studies.

Adolescent↗