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Biomedical subjects

M Sakuma

Publications and source records attributed to M Sakuma.

At least 199 records · Page 11Linked to original sources
PubMed1980

Calmodulins from muscles of marine invertebrates, scallop and sea anemone.

Invertebrate calmodulins of the sea anemone and scallop muscle were isolated and their properties were compared with those of vertebrate calmodulins from rabbit muscle and pig brain. The molecular weights estimated by SDS-polyacrylamide gel electrophoresis were similar to the molecular weight (16,500) of the vertebrate calmodulins. Every calmodulin contained 1 mol each of trimethyllysine and histidine, and high contents of acidic amino acids. The marine invertebrate calmodulins contained only one tyrosine in contrast to two tyrosines in the vertebrate ones. As a result, the UV absorption spectra were clearly different. The Ca2+-induced difference UV absorption spectra of the invertebrate calmodulins were indistinguishable from those of the vertebrate ones in spite of the difference in tyrosine contents. In tryptic peptide maps of invertebrate calmodulins, a few spots different from those of vertebrate calmodulins were observed in the basic and acidic peptide regions. The calmodulins of invertebrate muscles and that of rabbit skeletal muscle were almost indistinguishable in terms of the activation profile of rabbit skeletal myosin light chain kinase.

Amino Acids↗
PubMed1980

Manipulation of blood serotonin and platelets in the rat.

Dietary administration of L-tryptophan to rats failed to increase blood platelets. Instead platelet counts were decreased after feeding either a tryptophan-deficient or tryptophan-enriched (10%) diet, but were unchanged in animals on a 1% tryptophan diet. Platelet median volumes were not affected by any of these dietary regimens. As expected these dietary manipulations altered both brain and blood serotonin levels in the direction expected for a substrate dependence of serotonin biosynthesis.

Animals↗
PubMed1979

Measurement of urinary kallikrein acitvity by kinin radioimmunoassay.

We have established a simplified assay system for the measurement of urinary kallikrein activity by utilizing the sensitive and specific radioimmunoassay system of kinins previously reported from our laboratory. Kinins were generated by incubating urine samples (50 microliter) with kininogen (1500 ng) in the presence of kininase inhibitors, and the generated kinins were measured by radioimmunoassay. Since the cross reactivity of kininogen in the kinin radioimmunoassay system was not recognized at dose up to 1.0 microgram, the amount of untreated kininogen in the radioimmunoassay samples did not interfere with the measurement of kinins. This eliminated the necessity for a kininogen extraction procedure. A good linear correlation (r = 0.939, p less than 0.001) was observed between the urinary kallikrein activity determined by this assay system (kininogenase activity) and that by esterolytic acitvity. Urinary kallikrein activity was 3.3 +/- 0.9 microgram/min/24 hour urine (mean +/- SEM), 1.4 +/- 0.4 microgram/min/24 hour urine and 0.25 +/- 0.06 microgram/min/24 hour urine in 6 normal subjects, 7 patients with non-complicated essential hypertension and 4 patients with chronic renal failure, respectively. Thus, urinary kallikrein activity was significantly lower in the patients with essential hypertension (p less than 0.05) and the patients with chronic renal failure (p less than 0.01) than in the normal subjects.

Bradykinin↗
PubMed1978

A sensitive radioimmunoassay method for urinary kinins in man.

A sensitive and specific radioimmunoassay method for urinary kinins was developed, which uses antiserum against synthetic bradykinin in combination with labeled tyr8-bradykinin. The assay detects as little as 6 pg per tube of bradykinin. The dose-response curves of bradykinin. lysyl-bradykinin (kallidin), and methionyl-lysyl-bradykinin were almost identical. This suggests that the values estimated with bradykinin as the standard exhibit the total urinary kinins which contain these three peptides. The assay was performed without extraction of urinary samples, since a chromatographic study demonstrated that no interfering substances in urine samples remain in our assay system. The urinary levels of total kinins in 10 normal male subjects, three male patients with chronic renal failure, and 12 male patients with essential hypertension was 37.9 +/- 3.9 microgram/day (mean +/- S.E.M.), 9.0 +/- 5.1 microgram/day, and 24.2 +/- 5.2 microgram/day, respectively.

Adult↗
PubMed1975

A comparative study by the behavioral observation for sterotypy in the exceptional children.

1. Stereotyped behavior as a type of repetitive behavior was studied by observing four major groups of exceptional children by a natural observation method. The total 400 subjects are made up as follows: 46 with visual disturbance, 85 with auditory disturbance, 29 with infantile autism and 240 with mental retardation. 2. From analyses of our observational data, it was inductively proved that each group has its own characteristic sterotypy. There were marked differences in stereotypy between the auditory disturbance group and the visual disturbance group. Autistic children showed a perfect form of stereotypy and outstandingly bizarre characteristics. It was also found that blindism and autism have much in common. Stereotyped behavior shown by mentally retarded children differed with different intelligence levels. 3. There was no significant difference in the stereotypy appearance rate among the blind as well as the deaf-mute. Comparison between the blind with mental retardation and the blind with normal intelligence showed that there was significant difference of 0.5% or less. When taking the intelligence factor into account, significant differences aroused. As against the autism group, each group showed a significant difference of over 0.5%. In conclusion, it can be said that mental retardation factor has close bearing on the stereotypy appearance rate. 4. With respect to the cause of stereotyped behavior, the author based its argument on its own theory that blindism accrues from congenital visual disturbance. Weighing the fact that stereotypy differs between the blind and the deaf-mute, the author discussed with reference to the theory developed by Kaufman and Berkson that the inability of the child to monitor normal stimulation due to sensory disturbance produces frustration in him and this frustrated bodily need manifests itself in stereotyped movements. As for stereotypy of the mentally retarded children, the author pointed out that the arousal level theory is applicable only to the cases of severe-grade mental regardation, and that it fails to explain the parallelism between the differences of intelligence level and stereotypy. As regards stereotyped movements of the autistic children, due consideration was given to subtleties in action and bizarre nature of their behavior. Based on Orniz's theory that autistic children lack the constancy of central perceptual reception, the author maintained that the occurrence of stereotypy in autistic children suggests the underlying mechansims of perception are functioning pathologically as well as neurophysiologically. 5. As our observation as been conducted for a short period of time, the results might have been rather cross sectional. But the author thinks this shortcoming would have been made up for by Rutter's five-year follow-up study and the records available at the institutions which proved autism-stereotypy has continued to appear for a long period.

Adolescent↗