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Biomedical subjects

M Nagano

Publications and source records attributed to M Nagano.

At least 217 records · Page 12Linked to original sources

[Two-color flow cytometric analysis on human peripheral blood T-lymphocytes using monoclonal antibody BM-1 directed to Le(Y) determinant structure].

We developed a new assay method for the evaluation of Le(Y) antigen expression on human peripheral T-lymphocytes using the monoclonal antibodies BM-1, CD4 and CD8 by two-color flow cytometry. Le(Y) antigen expressed on human peripheral T-lymphocytes was stained with fluorescein isothiocyanate (FITC)-labelled BM-1 (anti Le(Y) monoclonal antibody). Le(Y) positive cells were simultaneously stained with phycoerythrin (PE)-labelled CD4 or CD8, then analyzed by flow-cytometer. Coefficients of variations in this double staining assays were 4.2% for BM-1 in CD4 and 5.3% for BM-1 in CD8, respectively. In 124 healthy volunteers 0.2-13.1% of CD4 and 2.5-12.5% of CD8 positive cells were BM-1 positive. Lymphocytes from 200 patients with acute or chronic viral hepatitis showed marked increase in BM-1 expression of CD8 positive cells during the acute phase and exacerbation of the disease. Moreover, BM-1 expression of CD4 cells was positively related with the course of the chronic hepatitis and the prognosis of each patients. Therefore, this new assay using BM-1 and CD4, CD8 monoclonal antibodies would reflect progression of viral hepatitis and its related immunological condition.

Adult↗

IgG-kappa type multiple myeloma in alcoholic cirrhosis--a case report.

Transition from polyclonal to monoclonal gammopathy resulted in myeloma in the course of cirrhosis is rare but of interest. We treated such a case of multiple myeloma of IgG-kappa type associated with alcoholic cirrhosis. The case was a 72-year-old Japanese male patient who was admitted because of ascites and edema. Physical examination and laboratory findings including liver histology were compatible with alcoholic cirrhosis. Serum electrophoresis revealed monoclonal hypergammaglobulinemia of IgG-kappa. Bence Jones protein in urine was positive. Bone scintigraphy and roentgenography revealed small punched out lesions in the skull. A bone marrow clot section showed marked infiltration of atypical plasma cells. From these findings multiple myeloma associated with alcoholic cirrhosis was diagnosed. On the basis of a review of the reported cases, the possible relationship between monoclonal gammopathy and chronic liver diseases was discussed.

Aged↗

Echocardiographic findings in hemodialysis patients treated with recombinant human erythropoietin: proposal for a hematocrit most beneficial to hemodynamics.

We investigated the hemodynamic effects of the correction of anemia with recombinant human erythropoietin (rHuEPO) in 28 hemodialysis patients with severe anemia. Echocardiograms were recorded before the administration of rHuEPO (period I) with a hematocrit of 19.2 +/- 1.5% (mean +/- SD) and repeated twice (periods II and III) when the hematocrit was increased to 25.7 +/- 1.1% and to 30.0 +/- 1.0%. Left ventricular end-diastolic dimension (LVDd) decreased from 51.0 +/- 6.1 to 48.8 +/- 5.8 and to 48.3 +/- 7.1 mm, but no changes were observed in left ventricular end-systolic dimension. Cardiac output (CO) decreased from 5.89 +/- 1.46 to 5.00 +/- 1.44 and to 4.67 +/- 1.33 l/min. The thickness of the interventricular septum and the left ventricular posterior wall remained unchanged. Blood pressure was kept rather constant, although antihypertensive therapy needed to be adjusted to prevent the occurrence or aggravation of hypertension. Total peripheral resistance increased from 1481 +/- 359 to 1832 +/- 487 and to 1946 +/- 493 dynes.sec/cm5. The decreases in LVDd and CO were significant between periods I and II, without further changes between periods II and III. More antihypertensive therapy was needed in period III than in period II. Similar echocardiographic results were observed in 10 patients in whom antihypertensive therapy was not required throughout the study. In conclusion, an increase in hematocrit to 25% would be appropriate in order to obtain an effective hemodynamic improvement with rHuEPO therapy in dialysis patients although a higher hematocrit level might be desirable in order to improve working capacity.

Adult↗

[Does pulmonary air embolism affect the pulsatility of pulmonary capillary blood flow in dogs?].

The difference in the uptake rate through the lungs between nitrous oxide and oxygen has been shown to represent the pulmonary capillary blood flow (Qc). The pulsatility of Qc, defined as the ratio of maximum Qc and mean Qc (Qc max/Qc), the ratio of Qc max and stroke volume (Qc max/SV), and the ratio of systolic Qc and SV (Vsyst/SV), has been also shown to indicate the pulmonary vasodilation as well as vasoconstriction. We measured Qc by means of body plethysmography in dogs with pulmonary air embolism, in order to evaluate its effect on the pulmonary vasculature. Ten adult dogs were anesthetized with pentobarbital and pancuronium, and were mechanically ventilated. A volume of air (0.5 ml/kg) was injected into the central vein. Although there was no significant change in systemic blood pressure, cardiac output, heart rate, and airway pressure after the injection of air, pulmonary arterial pressure and pulmonary vascular resistance increased significantly. Qc, Qc max, Qc max/Qc, and Qc max/SV decreased significantly after the air injection. Since these findings suggest that the pulmonary air embolism provoked pulmonary vasoconstriction, and attenuated the pulsatility of Qc, optimal pulmonary vasodilation therapy would be recommended to improve the pulmonary hypertension secondary to pulmonary air embolism.

Animals↗

Evidence for endothelin-1 release from resistance vessels of rats in response to hypoxia.

To elucidate further the contribution of endothelin into endothelium-dependent vasoconstriction evoked by hypoxia, we observed endothelin release during hypoxia. Endothelin was detectable in perfusate from mesenteric artery. Immunoreactive endothelin was confirmed as endothelin-1 by a reverse phase-HPLC. Endothelin release increased 4.1 +/- 1.3 to 12.4 +/- 2.0 pg/30 min without changing perfusion pressure. Thirty minutes of hypoxia stimulated endothelin release by 71 +/- 11% (P less than 0.05) and was associated with an elevation of perfusion pressure. These results suggest that endothelin contributes to endothelium-dependent vasoconstriction by hypoxia in mesenteric artery and may play an important role in the local peripheral vascular tone.

Animals↗

Dose calcium balanced heparin affect blood gas and electrolyte analysis?

The effect of calcium-balanced heparin (471896, CIBA CORNING) on blood gas and electrolyte analysis was evaluated, by comparing with that of sodium heparin (Na heparin). One ml of whole blood was collected into a syringe, which contained calcium-balance heparin (Ca balanced heparin) or Na heparin. 122 pairs of blood samples obtained from 15 patients were analyzed for Na, K, ionized calcium (Ca(++)), total hemoglobin, pH, P(CO)(2), and P(O)(2) by an automatic blood gas and electrolyte analyzer, CIBA CORNING model 288. There was a significant difference ( P << 0.05) in pH, P(CO)(2), Na, and Ca(++) between the two different groups. Ca(++) concentration was significantly less in Na heparin group than in Ca balanced heparin group, probably due to more chelation of Ca(++) by Na heparin than Ca balanced heparin. The present study suggests that the Ca balanced heparin has minimal effect on the blood gas and electrolyte analysis, and is a suitable anticoagulant for the Ca(++) measurement.

Journal Article↗

Impaired aldosterone production by long-term infusion of atrial natriuretic factor.

This study assessed the effect of chronic infusions of atrial natriuretic factor (ANF) on in vivo and in vitro production of aldosterone. Vehicle (saline) or rat ANF-(99-126) was intravenously infused at 100 ng.kg-1.h-1 for 5 consecutive days into male New Zealand White rabbits. At 5 days plasma ANF was 18 +/- 4.1 pg/ml in vehicle-infused and 48.5 +/- 9.0 in ANF-infused rabbits (P less than 0.01). Plasma renin activity was significantly less in ANF-infused rabbits (2.99 +/- 0.35 vs. 0.77 +/- 0.12 ng.ml-1.h-1, P less than 0.01); however no differences were observed in the basal plasma concentrations of aldosterone, corticosterone, potassium, or hematocrit. In in vivo studies, chronically administered ANF attenuated plasma aldosterone, but not pressor, responses to acutely infused angiotensin II given at doses of 4, 16, and 64 ng.kg-1.min-1 for 20 min each. In in vitro experiments, collagenase-dispersed adrenal capsular cells from ANF-infused rabbits exhibited significantly reduced maximal responses to adrenocorticotropic hormone, angiotensin II, and potassium. These results suggest that chronic small increases in circulating ANF can blunt selectively adrenocortical responses to aldosterone secretagogues without affecting pressor responses to angiotensin II.

Adrenal Medulla↗

Effects of endothelin on neuroeffector junction in mesenteric arteries of hypertensive rats.

The effect of endothelin, a novel vasoconstrictor peptide, on the adrenergic neuroeffector junction was investigated in isolated perfused mesenteric arteries of spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. The vasoconstrictor responses to periarterial sympathetic nerve stimulation and exogenous norepinephrine were determined. Infusion of endothelin-1 increased the baseline perfusion pressure dose dependently to similar extents in the two strains. A subpressor dose of endothelin-1 (10(-10) M) enhanced the pressor response to norepinephrine; its effect was greater in WKY rats than in SHR. Endothelin-1 (10(-12) to 10(-10) M) attenuated the pressor response to sympathetic nerve stimulation, and the degree of inhibition tended to be less in SHR than in WKY rats. Higher doses (3 x 10(-10) and 10(-9) M) of endothelin-1 enhanced the pressor response to nerve stimulation in both WKY rats and SHR. Endothelin-1 inhibited norepinephrine release from rat mesenteric arteries; the inhibition was significantly less in SHR than in WKY rats. These results suggest that endothelin enhances the responsiveness of alpha-adrenergic receptors to catecholamines, whereas it inhibits presynaptic adrenergic neurotransmission. Thus, endothelin can interact with the neuroeffector junction in addition to having a vasoconstricting effect in peripheral vessels. The difference in the mode of modulation by endothelin at the vascular neuroeffector junction in SHR from that in WKY rats might explain the maintenance of hypertension.

Animals↗

Altered myocardial contractility and energetics in hypertrophied myocardium.

Alterations of myocardial contractility and energetics were examined in cardiac hypertrophy induced by different types of cardiac overload. Myocardial contractility was estimated by isometric contraction of isolated left ventricular papillary muscles. Myocardial energetics were assessed from ventricular myosin isoenzyme patterns obtained by pyrophosphate gel electrophoresis. Cardiac hypertrophy was induced by endurance swim-training and sustained pressure-overload by abdominal aortic constriction or volume-overload created by an arteriovenous shunt. In swim-trained hypertrophied myocardium, isometric developed tension (T) and dT/dtmax showed a tendency to increase and response of dT/dtmax to isoproterenol increased significantly as compared with sedentary rats. Training shifted the left ventricular myosin isoenzyme pattern toward VM-1, which has the highest ATPase activity. In pressure- or volume-overloaded myocardium, dT/dtmax decreased significantly and mechanical response to isoproterenol also decreased (or tended to decrease in volume-overloaded hearts) as compared with the respective sham-operated controls. In pressure- or volume-overloaded hearts, left ventricular myosin isoenzyme pattern shifted toward VM-3, which has the lowest ATPase activity. These results indicate that alterations in myocardial contractility, mechanical catecholamine responsiveness and myocardial energetics in hypertrophied myocardium do not always display the same trend, but are greatly influenced by the causes or duration of cardiac overload.

Animals↗

[Effects of lead on drug metabolizing enzymes, cytochrome P-450 and hemeoxygenase in rats].

The effects of lead on the drug metabolizing system in liver microsomes and porphyrin metabolism in the bone marrow were studied using male Wistar rats (about 250 g in weight). To study the acute effects of lead, rats were given lead injection intraperitoneally once a day for three consecutive days at a dose of 0 (control), 0.1, 1.0, 10 or 50 mg/kg of lead in the form of lead acetate in a 5% glucose solution. In the 2nd experiment, the chronic effects of lead were studied by administering lead at a dose of 0 (control), 5 and 20 mg/kg once a week for 9 wk for a total of 10 administrations. After the last injection, each rat was fasted for 22 h in a metabolic cage to prevent the animal from eating bed chips or feces and was then sacrificed by decapitation. The rat liver microsome enzymes were used to evaluate the effects of lead on the hepatic functions. In the acute stage, lead decreased the activities of drug metabolizing enzymes, such as aniline hydroxylase and aminopyrine N-demethylase, and decreased the contents of microsomal cytochrome P-450 and cytochrome b5. In the chronic stage, lead decreased the cytochrome P-450 and cytochrome b5 contents and induced hypertrophic liver, but did not affect the activity of aniline hydroxylase. These findings suggest that the rat gradually gained resistance against lead toxicity in the chronic stage. In a supplementary experiment, lead was found to decrease the contents of heme in the microsome and to increase the activity of hemeoxygenase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Membrane fusion events during endocytosis in mouse kidney tubule cells detected by rapid freezing followed by freeze-substitution.

Membrane fusion events during endocytosis were examined in renal proximal tubule cells processed by rapid freezing followed by freeze-substitution. An extensive fusion site of the membranes between two apical vacuoles or a vacuole and a lysosome, which appeared as a pentalaminar structure, was not observed in this study, though such a pentalaminar structure has been found in chemically fixed specimens. In vitro experiments using subcellular fractions revealed that the pentalaminar structure did not always represent the initial stage of membrane fusion. Membrane fusion appeared to occur in a specific membrane site, wHere a minute pore connecting the two lumens was formed immediately after the two membranes came into contact with each other. Some pore necks showed an asymmetrical feature which consisted of a sharp corner and a gently curved corner. Enlargement of the pore appears to be mediated by a fibrous structure observed near the sharp corner of the pore neck.

Animals↗

[A benzodiazepine antagonist flumazenil in clinical use--a dose finding study].

The effective dose, usefulness and side effects of flumazenil, a specific benzodiazepine antagonist, have been investigated in 72 sleeping patients after the end of the surgical operation who had received flunitrazepam 0.03 mg.kg-1, a long acting benzodiazepine. The patients received intravenous injections of flumazenil 0.1 mg, 0.2 mg, 0.4 mg and 0.8 mg per person as initial doses. Four minutes after the injection of flumazenil, the percentages of the patients who were awake, were 47.4% in 0.1 mg group, 82.4% in 0.2 mg group, 82.4% in 0.4 mg group and 88.2% in 0.8 mg group respectively. There were several side effects observed in all the groups except 0.2 mg group. However, they presented no clinical problems. Therefore, flumazenil 0.2 mg as the initial dose, is considered appropriate.

Adolescent↗

[Acoustic evaluation of postoperative hoarseness in adult patients].

The present study was performed to evaluate postoperative hoarseness quantitatively by means of acoustic wave form analysis. Pitch and amplitude perturbation (PPQ, and APQ), and normalized noise energy (NNE) were measured along with the frequency characteristics in 51 adult patients undergoing elective surgery. The normal values for these acoustic parameters were less than 0.5%, less than 2.0%, and less than -10 dB, respectively. Vowel sound "E" was recorded and evaluated before the induction of anesthesia and on the morning of the day after the surgery. PPQ increased from 0.39% to 1.00% (P less than 0.05), APQ increased from 3.34% to 6.62% (P less than 0.05), and NNE increased from -9.19 dB to -4.74 dB (P less than 0.05). Eighteen percent of the patients showed abnormal values in all parameters preoperatively, but 45% of the patients postoperatively (P less than 0.05). These findings suggest that even the short term intubation resulted in the postoperative hoarseness, and this method is a useful and non-invasive bed-side test to evaluate postoperative hoarseness quantitatively.

Acoustics↗

Endothelin activates the vascular renin-angiotensin system in rat mesenteric arteries.

The effects of endothelin on the vascular renin-angiotensin system were examined in isolated perfused rat mesenteric arteries by measuring vascular renin activity and angiotensin II released into the perfusate. Infusion of endothelin (10(-9)M and 10(-11)M) increased the vascular renin activity and angiotensin II release. Pretreatment with nicardipine (10(-6)M), a calcium channel blocker, significantly suppressed these effects of endothelin. These results suggest that endothelin activates the vascular renin-angiotensin system via intracellular calcium metabolism. Vascular angiotensin II produced by endothelin may modulate the local effect of endothelin on the resistance vessels.

Angiotensin II↗