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Biomedical subjects

M Nagano

Publications and source records attributed to M Nagano.

At least 289 records · Page 16Linked to original sources
PubMed1985

Hypotensive mechanism of acetyl glyceryl ether phosphorylcholine (AGEPC) in dogs. Effects on hemodynamics and humoral factors.

One-O-hexadecyl-2-O-acetyl-sn-glycero-3-phosphorylcholine (AGEPC) was intravenously administered to anesthetized dogs to study the effects on hemodynamics and several endocrine factors. The effect of AGEPC on local blood flow was also studied by direct intra-arterial injection. Following intravenous injection, blood pressure and cardiac output decreased significantly (p less than 0.001). Changes in total peripheral resistance (TPR) and heart rate were biphasic. TPR increased significantly (p less than 0.01) after an initial slight reduction. Heart rate decreased significantly (p less than 0.01) with only a transient slight elevation. Femoral blood flow was increased (p less than 0.001) by intraarterial injection and decreased (p less than 0.05) by intravenous administration. Plasma norepinephrine (p less than 0.001), epinephrine (p less than 0.01), thromboxane B2 (p less than 0.001), 6-0-PGF1 alpha (p less than 0.01), aldosterone (p less than 0.001) and cortisol (p less than 0.001) were elevated, but plasma renin activity did not change. These results suggest that the hypotensive mechanism of AGEPC is due to both cardiosuppression and vasodilation. AGEPC increased plasma catecholamines, thromboxane A2, PGI2, aldosterone and cortisol which, in turn, may modify hemodynamics.

Aldosterone↗
PubMed1985

Experimental study on the enhancement of the neurotoxicity of methyl n-butyl ketone by non-neurotoxic aliphatic monoketones.

The neurotoxicity of methyl n-butyl ketone is known to be enhanced by combination with methyl ethyl ketone. This study was conducted to clarify the potentiating effect of aliphatic monoketones on the neurotoxicity of methyl n-butyl ketone. Rats were subcutaneously injected in the back with 4 mmol/kg/day of methyl ethyl ketone, methyl n-propyl ketone, methyl n-amyl ketone, or methyl n-hexyl ketone mixed with an equimolar dose of methyl n-butyl ketone five days a week for 20 weeks. The maximum motor fibre conduction velocity and the distal latency were measured every two weeks in the tail nerves of the treated animals and controls. All the monoketones tested enhanced the neurotoxicity of methyl n-butyl ketone. Of the compounds tested, methyl n-hexyl ketone, which had the longest carbon chain, enhanced the neurotoxicity of methyl n-butyl ketone most strongly. These results suggest that the length of the carbon chain of the aliphatic monoketones combined with methyl n-butyl ketone was related to the enhancement of the neurotoxicity of the neurotoxic compound.

Animals↗
PubMed1985

Sensitive assay and kinetic property of urinary inhibitor of Na+, K+-ATPase in sodium-loaded patients with essential hypertension.

A sensitive assay method to evaluate the inhibitor of Na+, K+-ATPase in human urine was developed by measuring the inorganic phosphate liberated from ATP in vitro using Na+, K+-ATPase from porcine cerebral cortex. Ouabain inhibited the Na+, K+-ATPase by competing with the potassium ion (an apparent Ki = 2.6 +/- 0.89 X 10(-8) M, n = 8) under the condition of 100 mM NaCl, 4.5 mM MgSO4 and 0.56 mM ATP. The apparent Km value of KCl was 0.4 mM. Factors inhibiting Na+, K+-ATPase were detected in the post-salt fraction on Sephadex G-15 chromatography following the ethanol extraction of lyophilized fresh urine of sodium loaded human subjects (300 meq Na+/day, for 4 days) with essential hypertension. Two active fractions around the 400 daltons following salt were eluted on Sephadex G-15 chromatography. The slower eluted factor competed kinetically with potassium ion, but the inhibitory activity was lost within two days during storage at 4 degrees C. The faster-eluted inhibitor lost its activity within a day. These results indicate that the unstable inhibiting factors of Na+, K+-ATPase exist in human urine and one of these factors inhibits ouabain sensitive Na+, K+-ATPase by binding to the potassium binding site (or very close to it), which exists at the outer surface of the cell membrane of this enzyme.

Binding Sites↗
PubMed1985

Electron microscopic cytochemistry of alkaline phosphatase in neurons of rats.

Fine structural localization of alkaline phosphatase activity was studied in the neurons of the cerebral cortex and the optics and sciatic nerves of the rat by electron microscopic histochemistry with the lead citrate method. Most neurons in the cerebral cortex demonstrated alkaline phosphatase activity on the plasma membrane of the nerve cell body and dendritic processes, from the thick trunk to the terminal postsynaptic boutons. Alkaline phosphatase was also associated with the axolemma, but only at the terminal presynaptic boutons and at the nodal and paranodal region of the nodes of Ranvier. The axolemma covered by myelin sheaths did not show any activity. The alkaline phosphatase reaction of the Ranvier node could also be demonstrated in the optic and sciatic nerves.

Alkaline Phosphatase↗
PubMed1985

Ultracytochemical demonstration of alkaline phosphatase activity in astrocytes and subependymal cells in the rat brain.

Ultrastructural localization of alkaline phosphatase activity was studied in astrocytes of the cerebral cortex and corpus callosum, and in the ependymal and subependymal cells of the lateral ventricle of normal rat brain by means of electron microscopic histochemistry employing the lead citrate method. Astrocytes exhibited alkaline phosphatase activity on the plasma membrane of the endfeet facing the vascular basement membrane and at the gap junctions, but not on other parts of the plasma membrane or in the cytoplasm. Immature astrocytes containing small bundles of filaments, a few glycogen granules and other cell organelles, exhibited alkaline phosphatase activity on the inner and outer nuclear membranes, the outer mitochondrial membrane and on portions of the plasma membrane. Thus, it was concluded that the distribution of alkaline phosphatase in astrocytes shifts from the cytoplasm and plasma membrane to the endfeet and gap junctions with cell maturation. Alkaline phosphatase activity was detected on the plasma membrane of the subependymal cells and surrounding processes, but not on the ependymal cells.

Alkaline Phosphatase↗
PubMed1985

A multiple regression analysis of hemoglobin values and iron status in Japanese farmers.

The authors performed multiple regression analysis of hemoglobin values and the parameters related to iron dynamics. The subjects consisted of 37 farmers whose Hb, Ht, GB, SI, %-St, SFR and FEP was examined once a month for one year. 19.2% of the female farmers had anemia of which 73.8% was iron-deficiency anemia, 13.7% being latent iron deficiency. Hb, GB and FEP in males and SI, %-St, SFR, FEP in females revealed clear seasonal variations. Multiple correlation coefficient between Hb and SI, %-St, SFR, FEP as independent variables was significant in females but not in males, and the ratio of contribution (38.7%) was not very high, however, the multiple correlation coefficient was significantly high (0.622). Standard regression coefficients between Hb and SFR, FEP were significantly high (p less than 0.01). When Ht and GB were added to these 4 variables, multiple correlation coefficients (male, 0.906; female, 0.957) were remarkably high, which means serum-related variables such as Ht and GB have an undeniably important role as explanatory variables of hemoglobin levels. These standard regression coefficients showed seasonal changes.

Adult↗
PubMed1985

Effects of temperature on papilloma growth in the newt, Cynops pyrrhogaster.

The effects of temperature on skin papillomas of newts (Cynops pyrrhogaster) were studied. Newts bearing these tumors were maintained for 30 weeks at 4 +/- 1 (S.E.), 10 +/- 1, 13 +/- 2, 25 +/- 1, and 30 +/- 1 degree. The diameters of the papillomas were measured externally. They decreased at 4, 25, and 30 degrees, and increased at 10 and 13 degrees. The effect of temperature on the tumor growth or regression began to appear from around the 10th week. Furthermore, when the temperatures were changed, it was possible to reverse the growth or regression of the tumors. Histologically, cell layers of the tumors became thin at 4, 25, and 30 degrees, but there were some differences between 4 and 25 or 30 degrees. The pigment layers became thick, and epidermal cells invaded dermal layer at 4 degrees, and clumps of cells separated from the surface of the tumors at 25 and 30 degrees. Mitotic indices were lower at 4, 25, and 30 degrees than in normal epidermis, but were about 3 times as high as normal tissue at 10 or 13 degrees. The relation between these results in the laboratory and seasonal fluctuations of these tumors in nature is discussed.

Animals↗
PubMed1984

Enzymatic and immunological comparison of alanine: glyoxylate aminotransferases from different fish and mammalian livers.

Alanine:glyoxylate aminotransferase was highly purified and characterized from mackerel liver. The purified enzyme had a mol. wt of approx. 200,000 with four identical subunits. It was specific for L-alanine and L-serine with glyoxylate and for L-serine with pyruvate as amino acceptor. The mackerel enzyme was similar to partially purified alanine:glyoxylate aminotransferases from other fish (sardine, gopher gray rock cod and yellow mackerel) liver with respect to mol. wts and substrate specificity. These fish enzymes were similar to mammalian liver alanine:glyoxylate aminotransferases 1 in substrate specificity and to mammalian alanine:glyoxylate aminotransferases 2 in mol. wts. An immunological cross-reactivity of hepatic alanine:glyoxylate aminotransferase was observed between mackerel and other fishes but not between mackerel and mammals.

Alanine Transaminase↗
PubMed1984

Relapsing polychondritis. Pathological and immunological findings in an autopsy case.

Relapsing polychondritis (RP) is a disorder of unknown etiology characterized by the destruction of cartilage. A case of RP in a 59-year-old male was autopsied, and systemic inflammation of various cartilages was confirmed. We demonstrated the circulating antibodies to Type II (cartilage) collagen. No antibodies to other collagen types were demonstrated. The presence of granular deposits of immunoglobulins, fibrinogen, and the C3 component of complement at the chondrofibrous junction was also demonstrated. From these findings, this case suggested that the pathogenesis of RP is related to an immune mechanism.

Adult↗
PubMed1984

Neurophysiological studies on the relation between the structural properties and neurotoxicity of aliphatic hydrocarbon compounds in rats.

In order to determine the specific structural properties responsible for neurotoxic activity, the comparative neurotoxicity of n-hexane, methyl n-butyl ketone, 2,5-hexanedione, and their relatives was investigated in the peripheral nerves of rats. The maximum conduction velocity of motor and sensory fibres and the motor distal latency of the tail nerves of rats were periodically examined in animals receiving repeated subcutaneous injections of 11 aliphatic monoketone or diketone compounds and their relatives for prolonged periods. A study of the comparative neurotoxicity of n-hexane, methyl n-butyl ketone, and their metabolites showed that 2,5-hexanedione was the most actively neurotoxic. Furthermore, a study of other symmetrical diketones with different carbon numbers showed that 2,4-pentanedione, which is structurally similar to 2,5-hexanedione, possessed a different type of neurotoxic activity than 2,5-hexanedione. Regarding aliphatic monoketone compounds, acetone, 2-pentanone, 2-heptanone, and 2-octanone were confirmed non-neurotoxic for the peripheral nervous system. Evidence from some previous reports, however, suggested that 3-heptanone, 4-octanone, and 5-nonanone might produce neuropathies by being converted to 2,5-diketones under specific conditions.

Animals↗
PubMed1984

A follow-up study on the lung disorders of rush (igusa) farmers exposed to "sendo" dust.

In the process of "tatami" mat production, from cultivating to weaving, rush farmers are exposed to "sendo" (dyer's earth) dust using it to prevent fading of the "tatami" mat color. It has been found that the workers tend to develop a relatively early stage of pneumoconiosis after about 20 years of this work. In 1980, 51 male (58.6 years old) and 37 female (54.4 years old) rush farmers, some of whom were previously examined in 1970, were re-examined for lung disorders. Chest X rays in the 1980 showed, 49.0% of males and 62.2% of females over 1/0 according to the 12 point profusion scale with irregular small opacities being dominant, a significant increase in the prevalence rates of pneumoconiosis compared with 1970 values (p less than 0.01 for both males and females). A relatively high prevalence of respiratory complaints and/or lung function impairment was also found. However, there were no severe cases and no significant changes were seen to have occurred during the seventies by those tests. It was also observed that increases in lung disorders during the decade were more common in the female workers. These findings suggest that the pathogenesis of rush farmer's pneumoconiosis might be in the histological changes of bronchial and/or alveolar walls by the deposition of "sendo" dust. The present study revealed that the lung disorders in the rush farmers may be associated with long-term inhalation of "sendo" dust, and the introduction of more suitable dust control measures in that processing must be actively pursued in the near future.

Adult↗