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Biomedical subjects

N Yagi

Publications and source records attributed to N Yagi.

At least 199 records · Page 11Linked to original sources
PubMed1977

The isolation and characterization of a lethal protein from Kintoki beans (Phaseolus vulgaris).

A lethal protein with hemagglutinating activity but without trypsin inhibitory activity was isolated from beans of Phaseolus vulgaris, cultiva, and Kintoki and proved homogeneous by ultracentrifugation, disc polyacrylamide gel electrophoresis, sodium dodesyl sulfate polyacrylamide gel electrophoresis and isoelectric focusing. The molecular weight was estimated to be 104, 000 by ultracentrifugal analysis and gel filtration on Sephadex G-200. The molecule dissociates into three identical subunits in the presence of 8 M urea or 0.1% sodium dodesyl sulfate. The amino acid composition was characterized by the high content of aspartic acid and the complete absence of methionine and cystine. The carbohydrate content was 8.1%; 5.0% mannose and 3.1% glucosamine. The addition of the lethal protein to a basal diet (0.4%) resulted in the intensive depression of the growth and finally in the death of rats. The intraperitoneal injection of 250 microgram per g body weight of mouse brought about an acute toxicity which caused death of all the injected mice.

Amino Acids↗
PubMed1977

Experimental extracranial-intracranial anastomosis.

A new experimental model for the study of extracranial-intracranial anastomosis has been developed. Canine external ethmoidal arteries have been anastomosed to the middle cerebral arteries. A 100% patency rate has been achieved ten days after operation. The surgical techniques are described. Using this model, we studied the changes of cortical intraarterial pressure and tissue O2 tension under a variety of conditions. From the results of this experiment, it is concluded that the restoration of the cortical intra-arterial pressure may be expected after anastomosis, that tissue O2 tension value depends upon restoration of the cortical intra-arterial pressure in the acute stage, and that O2 and CO2 inhalations have little effect on the brain ten days after middle cerebral arterial occlusion in spite of recovery of intra-arterial pressure with anastomosis. The experimental results suggest that the restoration of the intra-arterial pressure after anastomosis may be of no use in supplying oxygen to ischemic cortex in the chronic stage because of dysfunction of the cortical microvasculature.

Animals↗
PubMedDate not supplied

A new microviscometer for determining the viscosity of middle ear effusion.

A new microviscometer has been developed based on the capillary viscometer method. The device uses a glass sensor tube for aspirating 15-microliter samples. The relative viscosity of the samples was estimated from the negative pressure required for aspiration of the fluid. These pressures ranged widely from 1 centipoise (cp) to 10,000 cp. Measurement of the viscosity of middle ear effusions in 119 samples from 110 otitis media with effusion patients using this device revealed a close relation between their values and their gross appearance (serous less than seromucoid less than mucoid). The microviscometer is useful to determine the relative viscosity of a very small amount of fluid such as middle ear effusion.

Exudates and Transudates↗
PubMedDate not supplied

Intensification of the 5.9-nm actin layer line in contracting muscle.

According to the cross-bridge model of muscle contraction, an interaction of myosin heads with interdigitating actin filaments produces tension. Although X-ray equatorial diffraction patterns of active (contracting) muscle show that the heads are in the vicinity of the actin filaments, structural proof of actual attachment of heads to actin during contraction has been elusive. We show here that during contraction of frog skeletal muscle, the 5.9-nm layer line arising from the genetic helix of actin is intensified by as much as 56% of the change which occurs when muscle enters rigor, using a two-dimensional X-ray detector. This provides strong structural evidence that myosin heads do in fact attach during contraction.

Actins↗
PubMedDate not supplied

Effect of subacute manganese feeding on serotonin metabolism in the rat.

To clarify the effect of subacute manganese feeding on serotonin and mineral metabolism, Wistar rats were separated into two groups and fed two different diets, on a normal diet and another a manganese-supplemented diet. After 3 wk on these dietary regimens, the rats on the manganese-supplemented diet manifested the following abnormalities: blood pressure was decreased, brain serotonin was decreased, aromatic L-amino-acid decarboxylase activity in the brain was decreased, and manganese levels in heart, lung, and kidney were increased, whereas sodium, potassium, magnesium, and calcium levels in the brainstem were decreased.

Animals↗
PubMedDate not supplied

Perilymphatic oxygen tension and vasoactive drugs.

The oxygenation of the perilymph in response to the intravenous injection of vasoactive drugs has been measured in 67 cats using the polarographic method. Of all drugs used, only angiotensin induced a significant raise of perilymphatic PO2. Histamine, 50% glycerol and 7% Na2CO2 reduced the perilymphatic PO2. Papaverine, furosemid, pyridylcarbinol, naftidrofuryl and low molecular dextran have no significant effect upon the perilymphatic oxygen tension. Rapid changes of systemic blood pressure were found to correlate with subsequent modifications of the oxygen tension in the perilymphatic space.

Angiotensin II↗
PubMedDate not supplied

Effect of cholinergic drugs on the perilymphatic oxygen tension.

The effect of the intravenous injection of cholinergic drugs on perilymphatic oxygen tension (PO2) was measured using the polarographic method in 20 cats. Acetylcholine, pilocarpine and neostigmine produced minimal but statistically significant changes in perilymphatic PO2. Atropine and scopolamine did not influence the PO2 of the perilymphatic space. The reported results show that under normal conditions the cholinergic receptors of the vestibular vessels have little effect on the permeability of arterial PO2.

Acetylcholine↗
PubMedDate not supplied

Comparison of thread test of lacrimation to Schirmer test.

A modified Schirmer test using thread instead of filter paper has been previously reported. The present report compares the characteristics of thread and filter paper and establishes the normal range for the tear flow rate. The moisture absorption by a 5-mm wide strip of filter paper was 0.765 microL/mm and that by a thread was 0.054 microL/mm. The thread was 14 times more sensitive in detecting small amounts of fluid than was the filter paper. The thread test was used in 42 normal subjects. The normal range was 60% to 140% (+/- 3 SD), so a value of less than 60% was considered to indicate lacrimal hypofunction, and over 140%, hyperfunction.

Cerebellar Neoplasms↗
PubMedDate not supplied

Thread test of lacrimation in 110 cases of peripheral facial paralysis.

The thread test of lacrimation was performed on 110 patients with peripheral facial paralysis, and the changing values during the course of paralysis were observed. In 27.3%, the values stayed within the normal range of 60% to 140% of the intact side throughout the course of illness (normal type). In 14.5%, the value was over 140% before the start of recovery (hypertype 1). High values were seen in 39.1% during recovery from facial paralysis (hypertype 2), and values under 60% (hypotype) in 6.4%. Hyperlacrimation was frequently observed in Hunt's syndrome. Hypertypes, with temporarily increased lacrimation during the course of illness, seemed to reflect the regenerating activities of injured nerves in the early and recovery phases of facial palsy.

Facial Paralysis↗