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Biomedical subjects

M Higuchi

Publications and source records attributed to M Higuchi.

At least 433 records · Page 24Linked to original sources
PubMed1980

Analysis of relaxant effects of trapidil in isolated dog coronary artery.

Effects of 7-diethylamino-5-methyl-s-triazolo [1,5-a]pyrimidine (trapidil, Rocornal) on dog coronary arteries were investigated in vitro. Trapidil produced dose-dependent relaxations of isolated arteries which were contracted with potassium or prostaglandins F2 alpha. These effects of trapidil were not affected by atropine and propranolol. 5-Hydroxytryptamine (5-HT) and phenylephrine dose-dependently increased the tension of isolated coronary arteries. Trapidil could inhibit these effects of 5-HT or phenylephrine. The results indicate that trapidil has not a muscarinic action and an adrenergic beta-receptor stimulating action, but it has a 5-HT receptor and an adrenergic alpha-receptor blocking action.

Acetylcholine↗
PubMed1980

Natural humoral immunity in patients with malignant disease.

In order to assess the association of enhancement or suppression of humoral immune responses with cancer histology, sera from age and sex matched patients with sarcoma, melanoma and breast cancer and from normal donors were tested for natural antibodies in six serologic assays. Patients with melanoma were found to have a significantly higher level of antibody than the other groups tested. Antibody levels in patients with breast cancer were lowest.

Adult↗
PubMed1980

A serologic study of cultured breast cancer cell lines: lack of antibody response to tumour specific membrane antigens in patients.

Humoral antibodies to tumour associated membrane antigens of cultured human breast cancer cell lines were studied using the immune adherence (IA) test. Sera from 353 post-operative breast cancer patients and from twenty-five patients immunized by allogeneic breast cancer cells were tested against the MDA-MB-436 cell line. Fifty-five (15.6%) sera samples from the non-vaccinated group and 131 (77.3%) of 168 sera samples from the immunotherapy group were IA-positive to this cell line after absorption with bovine erythrocytes to exclude antibody to heterologous membrane antigens (HM Ag). Forty-five of the 55 positive-sera from the non-immunized group and 113 of the 131 positive sera from the immunized group became IA-negative after further absorption with lymphoblastoid cells autologous to MDA-MB-436. Subsequently, the twenty-eight positive sera remaining sere tested for oncofetal antigens (OFA). After absorption with OFA rich tissues (fetal brain and M14 melanoma cells), no reactivity remained in the sera samples. In order to identify antibodies specific to breast cancer antigens, the 129 sera samples from non-immunized patients were tested against four other breast cancer cell lines; MDA-MB-157, MDA-MB-231, MCF-7 and UCLASO-B1. Four sera which reacted to more than three of the cell lines were identified. The reactivity of three of the four was due to anti-OFA antibody. The last serum sample was reactive to anti-HLA antibodies. These results indicate that sera of patients with breast cancer contain antibodies to OFA, but do not detect breast histologic type specific antigens as tested by IA using five breast cancer cultured cell lines.

Antibodies, Neoplasm↗
PubMed1980

Ultrastructure of the articular cartilage after systemic administration of hydrocortisone in the rabbit: an electron microscopic study.

The acetabular cartilages from hip joints in adult rabbits receiving daily intramuscular injections of 1 or 5 mg hydrocortisone/kg body weight for periods of four or 12 weeks were studied by electron microscopy for quantitative analysis, nucleus to cell ratio, Golgi apparatus to cell ratio, rough endoplasmic reticulum to cell ratio and number of microvilli of chondrocytes and thickness of territorial matrix surrounding chondrocytes were obtained. Systemic steroid treatments decreased the volume of of rough endoplasmic reticulum and Golgi apparatus in chondrocytes, the number of microvilli, and the thickness of territorial matrix in matrix of the cartilage. These observations suggest that synthesis of proteoglycan and protein by chondrocytes is affected by steroid. These deleterious effects of steroid on cartilage begin with therapeutic dosages and progressively develop with increasing dosages of steroid or with increasing periods of time on steroid therapy.

Animals↗
PubMed1979

Responsiveness and high-energy phosphate metabolism of isolated dog coronary arteries.

The relationship between responsiveness and high-energy phosphate metabolism was observed in isolated dog coronary arterial strips before and after equilibration, under aerobic conditions. The strips responded slowly to potassium, norepinephrine, isoproterenol and 5-hydroxytryptamine before being equilibrated but did respond quickly to these drugs after being equilibrated for 1 hour under aerobic conditions. The contents of ATP, creatine phosphate (CP) and lactate were not significantly altered before and after equilibration for 1 hr. It is proposed that, before being equilibrated under aerobic conditions, coronary arteries may be unable to utilize ATP and CP due to injury of contractile or relaxant mechanisms resulting in a weak vascular responsiveness.

Adenosine Triphosphate↗
PubMed1979

A comparison of enzyme activity for energy production in the myocardium and conduction system.

Specific activities of enzymes in bovine hearts were measured. The enzyme activity ratios between the conduction system and the myocardium were 1.9 for G-6-PDH, 1.2 for PFK, 0.5 for total phosphorylase and LDH, 0.4 for GOT and MDH, 0.3 for SDH, 0.2 for Aldolase and CPK, and 0.1 for alpha GPDH. Approximate values for relative volume of Purkinje cells, nerve fibers and connective tissues in the conduction system were 30%, 8%, and 62%, respectively. It is concluded that activities of enzymes serving for anaerobic glycolysis in Purkinje cells are almost the same or slightly higher than those in the myocardium, and activity of enzyme for pentose shunt in the conductive tissue is higher than that in the myocardium.

Animals↗
PubMed1979

Analysis of vasodilatory action of a new nitroester agent, 2-nicotinamidoethyl nitrate (SG-75).

Effects of 2-nicotinamidoethyl nitrate (SG-75) on cardiovascular system were investigated using whole animals and isolated vascular smooth muscles of dogs and rabbits. In dogs in vivo SG-75 i.v. produced dose-dependent falls in systemic blood pressure (SBP) concomitant with increases in heart rate (HR). Hypotension by SG-75 was not affected by propranolol and atropine but slightly inhibited by diphenhydramine. Norepinephrine (NE) dose-dependently increased SBP, and SG-75 could not affect these effects of NE. In dog coronary arterial strips contracted with potassium, SG-75 produced a dose-dependent relaxation of these strips. These effects of SG-75 were not affected by propranolol and atropine, but slightly inhibited by diphenhydramine. NE dose-dependently increased the tension of helical strips prepared from rabbit femoral artery, rabbit aorta and dog coronary artery. But SG-75 could not alter these effects of NE. The results suggest that SG-75 may have not an adrenergic beta-receptor stimulating action, a muscarinic action and an adrenergic alpha-receptor blocking action, but an inconsiderable histamine-like action. Probably, a main action of SG-75 may be a nitroglycerin-like action.

Animals↗
PubMed1979

Comparison of Mg2+ vs Ca2+, K+ and actin-activation of myosin after trinitrophenylation.

While modification of six lysyl residues causes a near maximal decrease in Ca2+, K+, and actin + Mg2+ -activated myosin ATPase activities in rabbit skeletal muscle myosin, it takes nearly twice this number of modified lysyl groups to cause a similar alteration in canine cardiac myosin where trinitrophenylation is nonspecific. It appears that there are several rapidly reacting lysyl residues in cardiac myosin; the active site of cardiac myosin is protected by ATP after modification of a limited number of these rapidly reacting lysyl groups. In both myosins, after a charge modification of these rapidly reacting lysyl groups, 6 in rabbit skeletal muscle myosin and 10 in canine cardiac myosin, there is a decrease in Ca2+, K+, and actin + Mg2+ -stimulation of myosin but an activation of Mg2+ -stimulated myosin ATPase activity, thus making actin + Mg2+ -stimulated myosin ATPase activity more like activation with K+ or Ca2+ as compared to activation with Mg2+ alone.

Actins↗
PubMed1978

Clinical significance of serum bile acid measurement in liver diseases.

To determine the clinical significance of serum bile acid measurements, changes in the serum bile acid composition in liver diseases and endogenous bile acid clearance due to test meal loads were investigated. In the case of changes in the serum bile acid composition, a characteristic pattern of a remarkable increase of chenodeoxycholic acid (CDCA) was found in fulminant hepatitis. In patients with acute hepatitis, increases in CDCA were somewhat greater than those of cholic acid (CA) and there was tendency for these changes to precede changes in other liver function tests. In cases of extrahepatic obstructive jaundice, the CA/CDCA ratio was a large value exceeding 1.0. In investigations of endogenous bile acid clearance, serum bile acid concentration two hours after the text meal load clearly reflected the hepatic disorder and it was useful in differentiating between active and inactive form in chronic hepatitis and compensation and decompensation in liver cirrhosis.

Acute Disease↗
PubMed1978

Immunological, electrophoretic and kinetic properties of cardiac myosins from various species.

1. In a homologous radioimmunoassay for canine ventricular myosin light chains, the following percentages of cross-reactivities were obtained using the dog as a reference: human, 28%; sheep, 21%; cat, 8%; guinea-pig, 7%; rabbit, 5%; and rat, 4%. 2. In a homologous double diffusion immunoassay using specific gamma G to canine cardiac myosin heavy chains, dog cardiac myosin showed immunological identity with human and sheep cardiac myosin but partial identity with myosins of other species. 3. On a 5-20% polyacrylamide gradient, light chain C1 was electrophoretically distinct in some species; light chain C2 was electrophoretically identical in all species. 4. The K+-activated myosin ATPase of small animals was higher than that of larger animals at an alkaline pH; the same was true for Ca2+-activated myosin when assayed at pH 6.3.

Animals↗
PubMed1978

High-energy phosphate metabolism of isolated coronary arteries in the dog.

The correlation between phosphate metabolism and isometric contraction was investigated in helical strips from dog coronary artery. Adenosine triphosphate (ATP) and creatine phosphate (CP) contents of resting strips did not significantly change during anoxia. ATP content remained unchanged during potassium-contracture under aerobic conditions but was significantly reduced by anoxia. Pretreatment with iodoacetate resulted in a striking reduction in ATP content with a less marked decrease in CP content. ATP-depleting effect of iodoacetate was reduced slightly by the addition of pyruvate, but contractile response was not restored. It is considered that high-energy phosphates provided by anaerobic glycolysis can meet the energy requirements of resting coronary vessels but are insufficient for maintaining active tension. In resting strips equilibrated for 2 h in oxygenated bath solution, the reactivity to KCl and anoxia appears to be dependent on the availability of ATP.

Adenosine Triphosphate↗
PubMed1978

Effect of verapamil on the transmural energy metabolism in the isoproterenol-induced myocardial lesion.

The effect of verapamil on the isoproterenol (ISO)-induced transmural metabolic lesion in the left ventricular wall was investigated in the rat heart. The treatment with ISO 2.5 mg/Kg s.c. on 2 consecutive days resulted in significant decreases of creatine phosphate in the subendocardium (ENDO) and of adenosine triphosphate in the ENDO and the subepicardium. On the other hand, inorganic phosphate (Pi) and lactate (LA) were increased in both layers. These changes were more prominent in the ENDO. Pretreatment with verapamil 25 mg/Kg s.c. prevented the reduction of high energy phosphate compounds and the increases of Pi and LA in both layers by ISO.

Adenosine Triphosphate↗