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Biomedical subjects

S Fukuyama

Publications and source records attributed to S Fukuyama.

64 records · Page 4Linked to original sources
PubMed1989

Effects of norepinephrine and angiotensin II on plasma atrial natriuretic peptide concentration in humans.

To clarify the effects of norepinephrine and angiotension II (Ang II) on plasma atrial natriuretic peptide (ANP), both pressor substances were infused into normal volunteers, and plasma ANP levels and venous return were determined. When norepinephrine infusion elevated mean arterial pressure by 15 mm Hg, a transient increase of plasma ANP was observed. However, Ang II infusion showed no effect on plasma ANP levels, even though it also elevated arterial pressure. Superior vena cava flow and left atrial area, which were determined echocardiographically as the index of venous return, increased in the norepinephrine infusion study. However, in the study of Ang II infusion, there was no significant change in either superior vena cava flow or left atrial area. From these results, it was concluded that increased left atrial volume due to increased venous return is the major factor inducing ANP release in norepinephrine infusion.

Adult↗
PubMed1987

Plasma levels of human atrial natriuretic peptide in patients with hypertensive diseases.

Three types of antihuman atrial natriuretic peptide antiserum were obtained. From the study of cross-reactivity to human atrial natriuretic peptide fragments, it was suggested that antisera-1, -2, and -3 are mostly specific to 1-28, 5-25, and the ring structure, respectively. The estimated values of this hormone were significantly lower in the order of antisera-1, -2, and -3. Moreover, high performance liquid chromatographic study showed that various types of fragments of atrial natriuretic peptide exist in human plasma. These findings suggested that the highly specific antiserum to 1-28 human atrial natriuretic peptide such as antiserum-1 should be used to estimate the 1-28 human atrial natriuretic peptide levels in human plasma. From the study by using antiserum-1, it was concluded that the plasma human atrial natriuretic peptide increased in essential hypertensives, and in patients with primary aldosteronism, chronic renal failure, and malignant hypertension. Regarding the pathophysiological significance of increased plasma atrial natriuretic peptide, it is unlikely that this plays an important role in the etiology of essential hypertension or other hypertensive diseases, because the plasma level of this hormone is elevated in these patients. The increase of plasma atrial natriuretic peptide level in these patients should be considered to be a secondary or compensatory reaction to high blood pressure.

Aldosterone↗
PubMed1987

The role of plasma angiotensin I converting enzyme in regulation of renin-angiotensin system activity in patients with essential hypertension.

In order to investigate the role of plasma angiotensin I (pAI) converting enzyme on the activity of the renin-angiotensin system, we measured plasma renin activity (PRA), plasma angiotensin II (pAII), and plasma angiotensin I converting enzyme (pACE) activity in fourteen patients with essential hypertension before and after two hours of ambulation combined with intravenous furosemide administration. Significant increases were observed in the values of PRA (p less than 0.005), pAII (p less than 0.005) and ACE activity (p less than 0.05) after ambulation. The ratios of log pAII/log PRA were increased significantly after ambulation (p less than 0.005), and a significantly positive correlation was observed between log pAII/log PRA and ACE activity (p less than 0.01). These results suggested that not only PRA but also ACE activity contributed to the activity of renin-angiotensin system through the generation of AII.

Adult↗
PubMed1984

The effect of exogenous arachidonic acid on insulin secretion in isolated perifused hamster islets.

The effect of exogenous arachidonic acid on insulin secretion was investigated in a perifusion system using isolated hamster pancreatic islets. Exogenous arachidonic acid (10, 20, 50, 100 micrograms/ml) markedly stimulated glucose-induced insulin release. The enhancement of insulin release by arachidonic acid was completely inhibited by the cyclooxygenase inhibitor, sodium salicylate (0.5 mg/ml). In contrast to this, lipoxygenase inhibitor, nordihydroguaiaretic acid (10(-4) M), enhanced arachidonic acid-induced insulin secretion. Arachidonic acid hydroperoxide inhibited glucose-induced insulin release. Exogenous PG E2 (10(-5) M) potently elevated immunoreactive insulin (IRI) values throughout perifusion. These results suggest that the enhancement of insulin release by exogenous arachidonic acid is derived from newly synthetized prostaglandins and on the other hand, activation of the lipoxygenase pathway inhibits arachidonic acid-induced insulin secretion by decreasing the synthesis of prostaglandins.

Animals↗
PubMed1984

[MICs and MBCs of cefotaxime, desacetylcefotaxime and ceftriaxone against four principal bacteria causing meningitis].

The MICs and MBCs of cefotaxime (CTX), desacetylcefotaxime (Des-CTX) and ceftriaxone (CTRX) were determined in relation to 4 of the principal bacterial species which cause meningitis, i.e., S. pneumoniae, S. agalactiae, H. influenzae and E. coli. These tests were performed using final inocula of 10(8) cells/ml and 10(6) cells/ml. Comparison was made with the MIC and MBC values of benzylpenicillin (PCG) and ampicillin (ABPC). 1. Against 25 strains of S. pneumoniae, the MIC 90 values with inocula levels of 10(8) and 10(6) cells/ml were as follows: CTX, 0.05 and 0.024 micrograms/ml; Des-CTX, 0.39 and 0.20 micrograms/ml; CTRX, 0.10 and 0.05 micrograms/ml, respectively; and PCG, less than 0.012 micrograms/ml at both size. Similarly, the MBC 90 values were: CTX, 0.01 and 0.05 micrograms/ml; Des-CTX, 0.78 and 0.39 micrograms/ml; CTRX, 0.20 and 0.10 micrograms/ml; and PCG, 0.024 and 0.012 micrograms/ml, respectively. It is thus apparent that PCG showed the lowest values for both the MIC and MBC, followed by CTX, CTRX and then Des-CTX. Against 25 strains of S. agalactiae, the MIC 90 values with inocula of 10(8) and 10(6) cells/ml were as follows: CTX, 0.05 and 0.05 micrograms/ml; Des-CTX, 0.39 and 0.20 micrograms/ml; CTRX, 0.10 and 0.05 micrograms/ml; and PCG, 0.39 and 0.20 micrograms/ml, respectively. Similarly, the MBC 90 values of Des-CTX were 0.78 and 0.39 micrograms/ml, while the other 3 antibiotics showed the same values with both the 10(8) and 10(6) cells/ml inocula: 0.10 micrograms/ml for CTX, 0.20 micrograms/ml for CTRX and 0.39 micrograms/ml for PCG. Accordingly, CTX showed the lowest values, followed by CTRX and then PCG being about the same as Des-CTX. Against 25 strains of H. influenzae, the MIC 90 values with inocula levels of 10(8) and 10(6) cells/ml were as follows: CTX, 0.10 and 0.05 micrograms/ml; Des-CTX, 0.39 and 0.39 micrograms/ml; CTRX, 0.10 and 0.05 micrograms/ml; and ABPC, 50 and 6.25 micrograms/ml, respectively. Similarly, the MBC 90 values were: CTX, 0.20 and 0.10 micrograms/ml; Des-CTX, 1.56 and 1.56 micrograms/ml; CTRX, 0.39 and 0.20 micrograms/ml; and ABPC, greater than 100 and 50 micrograms/ml, respectively. Accordingly, in terms of the MIC 90, CTX and CTRX showed the same values, but in terms of the MBC 90 CTX was superior. (ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1976

Epizootic congenital arthrogryposis-hydranencephaly syndrome in cattle: isolation of Akabane virus from affected fetuses.

Previous serolgoical studies strongly suggested Akabane virus to be the etiologic agent of epizootic abortion and congenital arthrogryposis-hydranencephaly in cattle, and this view was further corroborated in this study by the isolation of the virus from an aborted fetus in an epizootic of the disease and from a fetus extracted froma cow which was suggested by serologic tests to have a recent infection with the virus. The latter fetus had histological changes of encephalomyelitis and polymyositis, and specific antigens of Akabane virus was shown by the immunofluorescent technique in brain tissues as well as skeletal muscular tissues. The virus was recovered from various fetal tissues and fluids, and in relatively large amounts from brain, spinal cord, cerebral fluid, skeletal muscles and fetal placenta. The intracranial inoculation of suckling mice, 1-2 days of age, was the most sensitive system for Akabane virus isolation and HmLu-1, a continuous cell line from hamster lung, seemed almost as sensitive as suckling mice.

Abortion, Veterinary↗