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Biomedical subjects

Y Mizunuma

Publications and source records attributed to Y Mizunuma.

15 recordsLinked to original sources
PubMed2004

Metabolic profiles and bile acid extraction rate in the liver of cows with fasting-induced hepatic lipidosis.

This study was designed to monitor lipid profile in the portal and hepatic blood of cows with fasting-induced hepatic lipidosis, and to compare the results with those in the jugular blood. The work was also carried out to investigate bile acid (BA) in these vessels, and further to investigate BA extraction rate in the liver. Five cows were equipped with catheters in the portal, hepatic and jugular veins (day 0), fasted for 4 days (day 1-day 4) and then refed (day 5-day 11). Before morning feeding, blood was sampled before, during and after fasting from the catheterized vessels. In the portal blood, the concentration of non-esterified fatty acids (NEFA) showed a progressive increase and at day 5 there was an approximate twofold rise. Increased NEFA concentrations were also found similarly in the other two veins. At day 5, beta-hydroxybutyrate (BHBA) in the portal, hepatic and jugular blood rose to 197, 190 and 186% of the pre-fasting value, respectively. However, the concentrations of NEFA and BHBA in the three veins gradually returned to pre-fasting concentration during the refeeding period. Compared with the pre-fasting value at day 0, the content of liver triglyceride (TG) increased significantly at day 5 (P < 0.01). In the liver, the hepatic extraction rate of BA dropped from 3.1 times pre-fasting to 2.2 times during fasting. There were no significant differences in the concentrations of glucose, TG, total cholesterol, cholesterol esters, free cholesterol and phospholipids. The results of the current study show that metabolic alterations occur in the portal, hepatic and jugular veins during induction of hepatic lipidosis in cows, and mostly metabolites, with exception of BA concentration, run parallel. The decreased BA extraction rate in the liver of fasted cows was considered to reflect hepatic cell impairment caused by TG accumulation. Hopefully, the findings, at least in part, contribute to the explanation of the pathophysiology of hepatic lipidosis in dairy cows.

Animals↗
PubMed2000

Participation of angiotensin II in pressor response and norepinephrine release to spinal nerve stimulation in pithed rats.

Experiments were carried out to examine whether endogenous angiotensin II (A-II) is involved in the regulation of release of norepinephrine (NE) elicited by the stimulation of spinal sympathetic nerves in pithed rats. It was assessed in terms of the alterations in concentrations of arterial blood plasma A-II and NE elicited by nerve stimulation (5 Hz, 50 V, 1 msec for 45 s) in pithed rats under vehicle or captopril (3 mg/kg, i.v.) treatment. Comparative study with pentobarbital anesthetized rats showed that pithing rats have the characteristics of lower basal blood pressure and lower NE level, whereas they have higher basal A-II level. In pithed rats treated with vehicle, pressor response to nerve stimulation was accompanied by increases in both A-II and NE level. In rats treated with captopril, the nerve stimulation caused about 40% lower increases in pressor response and NE level than those observed in rats treated with vehicle. These results suggest that the sympathetic nerve-induced NE release is facilitated by endogenous A-II in pithed rats, and that captopril exerts its inhibitory effect on the pressor response to nerve stimulation through the suppression of this interaction.

Angiotensin II↗
PubMed1996

Endothelium-dependent vasodilatation is not selectively impaired in patients with chronic heart failure secondary to valvular heart disease and congenital heart disease.

This study examined possible selective impairment of endothelial dysfunction in the peripheral vascular bed in patients with chronic heart failure in the absence of confounding factors influencing endothelial function (i.e. hypertension, hypercholesterolaemia and diabetes mellitus). Several recent studies have suggested that endothelium-dependent peripheral vasodilation is impaired but endothelium-independent vasodilation is preserved in patients with chronic heart failure. However, a classical paper has demonstrated that sodium nitrite-mediated calf blood flow is clearly depressed in patients with valvular heart disease and cardiomyopathy. We examined forearm blood flow changes mediated by acetylcholine and nitroprusside in patients with valvular heart disease (n = 55) or congenital heart disease (n = 13), and a comparison was made with healthy volunteers (n = 21). The blood flow changes mediated by acetylcholine and nitroprusside were significantly impaired in both patient groups (P < 0.01). When blood flow responses were collected from all patients, two types of vasodilatory capacity were found to have decreased significantly with increasing clinical severity of heart failure (New York Heart Association functional class; P < 0.01). This suggests that the peripheral vasodilatory responses mediated by endothelium-dependent and endothelium-independent vasodilators are significantly impaired in patients with symptomatic chronic heart failure due to non-ischaemic heart disease.

Acetylcholine↗
PubMed1995

Myxoma of the mitral valve detected by echocardiography and magnetic resonance imaging.

Myxomas of the mitral valve diagnosed during life are exceedingly rare. We employed transthoracic and transoesophageal echocardiography and magnetic resonance imaging enhanced by gadolinium-diethylene-triamine-pentaacetic acid in a patient with palpitations. After these examinations clearly demonstrated a myxoma on the atrial side of the posterior mitral valve leaflet, urgent surgery was performed. When a small tumour of the mitral valve exists, these examinations are useful not only for detecting and characterizing the tumour, but also for deciding the optimal surgical management.

Adult↗
PubMed1995

Transient cortical blindness following bypass graft angiography. A case report.

Transient cortical blindness, an uncommonly recognized complication of cerebral angiography, is an exceedingly rare event after cardiac catheterization and angiography. This report describes a sixty-two-year-old patient who had transient cortical blindness following bypass graft angiography. In this case, the authors showed that cortical blindness was associated with the breakage of the blood-brain barrier (BBB) and an increase in vascular permeability rather than with primary cerebral circulatory insufficiency. When the possibility exists that an excess volume of contrast medium may enter the cerebral circulation as in this case, that is, following a coronary artery bypass graft (CABG) using the internal mammary artery (IMA), precautionary measures may be necessary such as changing the type of contrast medium to be used or decreasing the volume injected. When cortical blindness occurs, it is a serious clinical problem whether transient or permanent. Therefore, the circumstances leading to this complication should be understood to determine suitable treatment and management.

Blindness↗
PubMed1990

Multiple myeloma associated with amyloidosis and t(1;20)(q21;q11) translocation.

A 59-year-old woman with nephrotic syndrome was diagnosed as having primary amyloidosis based on the detection of amyloid deposition (AL-protein) in the esophagus and kidneys. Bone marrow aspirate showed plasmocytic proliferation, leading to a diagnosis of multiple myeloma (IgG lambda-type). In addition, a very rare translocation t(1; 20) (q21; q11) was seen by chromosomal analysis of both the bone marrow and peripheral blood.

Amyloidosis↗
PubMed1988

Relationship between the occurrence of late potential on the body surface ECG and cardiac performance in myocardial infarction.

Comparative evaluations of the percent of the perimetric circumference of infarction and cardiac performance for the occurrence of late potential were performed in 12 normal subjects and 22 patients with old myocardial infarction (MI). All patients were in normal sinus rhythm without bundle branch block. Bipolar X, Y, and Z leads were signal-averaged using a bandpass filter with a low-cut frequency of 100 Hz and a high-cut frequency of 300 Hz. The filtered signals for the three leads were displayed and combined into a vector magnitude, square root of X2 + Y2 + Z2. The percent ratio of the root mean square voltage in the last 40 msec of the QRS complex was calculated against that of the total filtered QRS (%RMS40). The value of the standard deviation (SD) in the phase distribution was obtained by the Fourier analysis of multi-gated blood pool images. Significant differences were observed among MI with late potential, MI without it and the normal subjects for %RMS 40 (5.7 +- 2.8% vs 26.9 +- 8.1, 37.5 +- 10.8%). Left ventricular ejection fraction was lower in MI with late potential (19.7 +- 7%) compared to that of MI without it (33 +- 18%) and the normal subjects (60 +- 4%); the value of SD was higher in MI with late potential (64 +- 21 degrees), compared to that of MI without it (43 +- 20 degrees) and the normal subjects (9 +- 4 degrees). These findings showed that the percent ratio of the last 40 msec RMS voltage (%RMS 40) was found to discriminate effectively among MI with and without late potential and normal subjects. It was suggested that the amount and structure of the infarcts may be important factors in the occurrence of late potential.

Adult↗
PubMed1983

Immunoreactive somatostatin and vasoactive intestinal polypeptide in adrenal pheochromocytoma. An immunochemical and ultrastructural study.

An adrenal pheochromocytoma producing somatostatin (SRIF) and vasoactive intestinal polypeptide (VIP) in a 17-year-old boy is presented. High concentrations of immunoreactive (IR)-SRIF were found in plasma taken from the antecubital vein (31.0-33.0 pg/ml) and the inferior caval vein near the tumor (54.6 pg/ml), but after removal of the tumor the values became normal (11.0-15.2 pg/ml). In two portions of the resected tumor, considerable but different amounts of IR-SRIF (151.7 and 12.1 ng/g wet wt) and IR-VIP (13.0 and 5.5 ng/g wet wt) were demonstrated with size heterogeneities. Immunohistochemically, many IR-SRIF cells and a few IR-VIP cells were observed, but no cell reacting with both anti-SRIF and anti-VIP sera was found. Electronmicroscopically, many tumor cells had catecholamine-like granules (250-350 nm in diameter) while some others had VIP-like granules (110-140 nm in diameter). However, no granules resembling the SRIF granules seen in the pancreatic D cells were found. This seems to be the first report of an adrenal pheochromocytoma that produces SRIF and VIP simultaneously. It provides information on the histogenesis of hormone-producing neurogenic tumors.

Adolescent↗
PubMed1976

Histochemical studies of monoamine oxidase in experimental myocardial infarctions.

Sequential histochemical studies were conducted to determine the level of monoamine oxidase (MAO) activity in the infarcted tissue of the experimental myocardial infarction in dog. MAO activity was not found in the normal heart muscle, but the activities were present in the wall of the coronary artery histochemically. Fibroblasts and collagen fibers began to take the place of the destroyed heart muscles in the infarcted area from 10 days after the coronary occlusion in dogs, and MAO activities were noted sporadically in the fibroblasts and the interstices of the collagen fibers in the infarcted area. MAO activities increased histochemically in the fibroblasts and the fiber interstices in the infarcted area 10 days or more after the coronary occlusion. These findings suggested the presence of the active collagen metabolism outside the myocardial cells in the infarcted area in the recovery stage of the experimental myocardial infarction. It was also suggested that the interstices of the collagen fibers in the myocardial wall constituted the lymphatic ducts outside the blood vessels and that the MAO activity in serum determined by the method in which tryptamine hydrochloride was used as substrate might indicate the grade of fibrosis of the myocardial tissue in the infarcted areas.

Animals↗