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Biomedical subjects

K Fujino

Publications and source records attributed to K Fujino.

At least 73 records · Page 4Linked to original sources
PubMed1990

[A case of pulmonary tuberculosis associated with adult respiratory distress syndrome during corticosteroid treatment of rheumatoid arthritis].

We reported a case of 64 year-old female patient of pulmonary tuberculosis associated with ARDS during corticosteroid treatment of Rheumatoid Arthritis. On admission her chief complaints were fever, fatigue and dyspnea. A chest roentgenogram showed diffuse alveolar infiltration consistent with pulmonary edema. Arterial blood gas studies showed severe hypoxemia. We clinically diagnosed so-called ARDS. Smears of sputum for acid fast bacilli were negative, but transbronchial lung brushing by bronchofiberscope revealed many acid fast bacilli. Intensive therapy with anti-tuberculosis drugs (INH, RFP, SM), high dose corticosteroid (methylprednisolone) therapy and mechanical ventilation was started. During the following 2 weeks, the PaO2 rose gradually and the alveolar infiltration on the chest roentgenogram disappeared. The experience of this case to emphasized the importance of suspecting this condition because pulmonary tuberculosis is a potentially curable cause of ARDS and it should also be emphasized that the good treatment effect could be expected with combined use of high dose corticosteroid and mechanical ventilation.

Arthritis, Rheumatoid↗
PubMed1989

Vector U loop in patients with old myocardial infarction.

The U loop of the vectorcardiogram was examined qualitatively and quantitatively in 100 normal subjects and 67 patients with old myocardial infarction, using a direct-writing vectorcardiograph with memory function. In the control group, the U loop was directed to the left, anteriorly and inferiorly, and it was inscribed counterclockwise in the horizontal plane. In patients with anterior myocardial infarction, the U loop tended to be displaced to the right, and in patients with inferior myocardial infarction to the right and superiorly. The shape of the U loop in patients was also different from that of normal subjects. The maximum U vector was significantly smaller in magnitude both in patients with anterior and inferior myocardial infarction than that of normal subjects (p less than 0.01). In patients with ventricular aneurysm, the magnitude of the maximum U vector was significantly smaller and its direction was displaced more to the right and posteriorly than those without aneurysm (p less than 0.01). In standard 12-lead electrocardiogram (ECG), observation of the U wave in patients with old myocardial infarction was difficult, especially in the limb lead, because of the small size of the U wave. Therefore, vectorcardiographic observation may be more useful than electrocardiographic observation for the analysis of the U wave in patients with old myocardial infarction.

Adult↗
PubMed1989

Effects of lidocaine and quinidine on post-repolarization refractoriness after the basic and premature action potentials: consideration of aim of antiarrhythmic drug therapy.

Antiarrhythmic drugs are often more effective in suppressing ventricular tachycardias than are background premature extrasystoles. The mechanism of action of these agents was examined by studies on the effects of lidocaine and quinidine on post-repolarization refractoriness of both basic and premature action potentials. In the absence of antiarrhythmic drugs, the excitability threshold was relatively constant after the end of repolarization of both basic and premature action potentials. In the presence of lidocaine or quinidine, the strength-interval curves were shifted to the right and superiorly, and the two drugs had different effects on the course of the strength-interval curve and Vmax recovery, presumably due to use-dependent V max block. Moreover, depressions of Vmax and excitability were more marked after the premature action potential than after the basic action potential. These results suggest that lidocaine and quinidine cause more depression of the excitability of second premature contractions than of first premature contractions, and also indicate that for protection against sustained ventricular tachycardias, it may not be necessary to suppress chronic premature ventricular contractions.

Action Potentials↗
PubMed1989

Magnetic resonance imaging in autism: preliminary report.

MRI was performed for 18 autistic patients, 11 patients with uncomplicated mental retardation (MR) and 18 controls. In autism and MR, and altered left/right relationship of the frontal lobe volume was observed. The altered asymmetry was more severe in autism than in MR. The brain stem was smaller in MR than in the controls, and the right operculum was smaller in MR than in autism. These findings are consistent with the hypothesis that some autisms may involve a type of early developmental abnormality. Furthermore, our results suggest that autism may involve a type of structural brain impairment different from MR.

Autistic Disorder↗
PubMed1989

Magnetocardiographic studies of ventricular repolarization in old inferior myocardial infarction.

Isomagnetic maps of 50 normal subjects (control group) and 23 patients with old inferior myocardial infarction (IMI group) were recorded in order to analyse T wave abnormalities in inferior myocardial infarction. The T wave of the magnetocardiogram (MCG) in the control group showed negative deflections in the left upper portion and positive deflections in the right lower portion, thus resulting in a T vector directed leftward and inferiorly. The T wave of the IMI group was flat or positive in the left upper portion and flat or negative in the right lower portion, suggesting a T vector directed superiorly. In addition, opposing dipoles were observed in 36.4% of the IMI group; i.e. one directed superiorly, presumably due to inferior myocardial ischaemia, and the other directed inferiorly due to normal repolarization. Localized T vector abnormalities could be detected by the MCG in some cases, in which coronary T waves of the standard electrocardiogram had returned to normal. Furthermore, multiple dipoles were more frequently observed in the isomagnetic map than in the isopotential map (5 vs. 15; P less than 0.01). These results suggest that the MCG is helpful in diagnosing myocardial ischaemia when this is not detectable on the electrocardiogram.

Adult↗
PubMed1989

The positive inotropic effect of pimobendan involves stereospecific increases in the calcium sensitivity of cardiac myofilaments.

We have studied the effect of pimobendan (UD-CG 115 BS) on the electrical, mechanical, and biochemical activity of intact and detergent-skinned preparations of cardiac muscle. Racemic pimobendan increased the contractile force of guinea pig papillary muscle preparations and this positive inotropic action was associated with potentiation of the Ca2+-dependent slow action potentials (APs). However, in the presence of 25 mM [K]0 and maximally activating concentrations of isoproterenol, isometric force was increased further by addition of 50 microM pimobendan with no effect on the slow action potential. Experiments with chemically skinned heart muscle fibers showed that pimobendan, in a dose-dependent manner, increased active tension developed at submaximally activating concentrations of Ca2+. The tension-cost (unit increase in ATPase rate/unit increase in force) was unchanged in the presence of pimobendan. Force-pCa and ATPase-pCa relations of skinned fiber preparations contracting isometrically were shifted to the left by 0.15-0.20 pCa units in the presence of 50 microM pimobendan. The mechanism for this effect was shown to be an increase in the Ca affinity of the regulatory binding sites of troponin C (TNC). These effects are due mainly to the l optical isomer of pimobendan. Addition of either the d or l isomer of pimobendan to preparations. maximally stimulated by 1 microM isoproterenol, did not affect the slow AP parameters, but did increase contractile force to 124% of control by the d isomer and to 184% of control by the l isomer. The Ca2+-sensitizing effect of l-pimobendan on skinned fiber preparations was substantially greater than that of the d isomer.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗
PubMed1989

The T wave abnormality in the magnetocardiogram.

The T wave changes in left ventricular hypertrophy and old inferior wall myocardial infarction were studied by the isomagnetic map to compare with those in the isopotential map. The isomagnetic map could detect the instantaneous current source, and the abnormal repolarization vector was more frequently observed in the isomagnetic map than in the isopotential map. The multiple dipoles were more frequently observed in the isomagnetic map, which has been difficult to detect by the isopotential map. The present study showed that repolarization in ventricular hypertrophy and myocardial ischemia is very complex and both normal and abnormal repolarization vectors are present, which might be opposite in direction. In some cases, these vectors were summated and only one dipole could be shown in the electrocardiogram or isopotential map. These results suggest that the magnetocardiogram is useful in detecting opposing current dipoles tangential to the heart.

Adult↗
PubMed1989

Coronary arteriovenous fistula with vasospastic angina.

A 50-year-old man was admitted to our hospital because of chest pain. Twenty-four-hour ECG recording demonstrated ST-segment depression and elevation at the time of spontaneous angina. During treadmill exercise test, the patient developed chest pain with ST-segment depression in leads V4 to V6. After the administration of nifedipine (10 mg), the patient was able to reach up to the maximum predicted heart rate without anginal symptoms and ST-T changes. Coronary arteriogram demonstrated 50% stenosis at the proximal portion of the left anterior descending artery (LAD) and two small fistulas originated from LAD to pulmonary artery. Spasm was induced at the proximal portion of LAD by the hyperventilation. If patients with coronary arteriovenous fistula (CAVF) have symptoms, elective CAVF ligation has been recommended. However, this case suggests that coronary spasm could be one of the cause of angina pectoris in patients with CAVF. Elective CAVF ligation must be carefully indicated in CAVF patients with angina pectoris.

Angina Pectoris↗
PubMed1989

[Studies on the Rett syndrome. Part 1. Prevalence of the Rett syndrome].

The Rett syndrome (RS) is currently diagnosed by its characteristic clinical features and course since specific biochemical markers have not been established. These features include psychomotor regression after early periods of normal development, autistic appearances, hand stereotypy and loss of purposeful hand skills. Since these features may be seen in other children with neurological disorders, it is possible that many patients admitted to residential facilities or schools have RS but have not been diagnosed as such. We undertook a survey of the schools and residential facilities for handicapped children at Tokushima Prefecture to determine the prevalence of RS in the Japanese. The prevalence of RS in Tokushima prefecture was 0.36/10,000 girls at age 15 and under (0.37/10,000 girls at 7-15 years). The prevalence of RS in our study was lower than the European studies.

Adolescent↗
PubMed1988

Isomagnetic maps in right ventricular overloading.

Isomagnetic maps were recorded in normal subjects and in patients with systolic overloading of the right ventricle. The isomagnetic maps examined in this study indicated the instantaneous current source of the heart by applying the "corkscrew rule." The magnetic field recorded by a second derivative gradiometer detected clearly the cardiac current source from the right ventricle, which is located close to the anterior chest wall, and improved diagnostic sensitivity. Moreover, the isomagnetic map showed multiple dipoles, which are difficult to detect in the electrocardiogram or isopotential map. These results suggest that the magnetocardiogram provides useful information on current sources to supplement information obtained by the conventional electrocardiogram.

Adult↗
PubMed1988

Analysis of the T wave of the magnetocardiogram in patients with essential hypertension by means of isomagnetic and vector arrow maps.

Magnetocardiograms (MCGs) of 50 normal subjects and 40 patients with essential hypertension were recorded to determine the value of the MCG for detecting abnormal repolarization. Among the patients with essential hypertension, there were nine cases (22.5%) in whom isopotential maps did not show rightward repolarization vectors but isomagnetic and vector arrow maps showed a rightward repolarization vector in some areas in addition to the normal repolarization vector. Departure maps of the ECG showed an increased repolarization vector directed anteriorly in some of these cases. The repolarization abnormality was recognized in only the MCG departure map in four cases, while no case showed abnormality in only the ECG departure map. With the progress of hypertension, the repolarization abnormality was seen more frequently and its detection using the MCG was higher than that using the ECG. Furthermore, multiple dipoles were detected more frequently from the MCG than from the ECG. Thus the MCG seems more useful than the ECG in the analysis of repolarization abnormalities in essential hypertension.

Adult↗
PubMed1988

Sensitization of dog and guinea pig heart myofilaments to Ca2+ activation and the inotropic effect of pimobendan: comparison with milrinone.

We compared the effects of the newer inotropic drugs, pimobendan (UD-CG 115 BS) and milrinone (Win 47203), on the electrical, mechanical and biochemical activity of intact and detergent-skinned preparations of cardiac muscle. Both of these agents increased contractile force of guinea pig papillary muscle preparations bathed under physiological conditions or depolarized with 25 mM K+o. The positive inotropic action was associated with potentiation of the Ca2+-dependent slow action potentials (APS). Contractile force developed in the presence of 25 mM [K]o and 1 microM isoproterenol was increased further by addition of 50 microM pimobendan with no effect on the slow action potential. Milrinone (50 microM) did not produce a further increase in the force or potentiate the slow APs. Pimobendan, in a dose-dependent manner, increased active tension developed by chemically-skinned dog heart muscle fibers at submaximally activating concentrations of Ca2+, whereas milrinone did not. At pCa 6.25, the half-maximal concentration of pimobendan for stimulation of force development was about 40 microM. At maximally activating levels of Ca2+ (pCa 4.5), pimobendan had little or no effect on force development. The effect of pimobendan on force was paralleled by changes in the Ca2+-activated Mg-ATPase activity of the isometric skinned fiber preparations. Moreover, the tension-cost (unit increase in ATPase rate/unit increase in force) was unchanged in the presence of pimobendan. Milrinone did not affect ATP hydrolysis by the skinned fiber preparations. Force-pCa and ATPase-pCa relations of skinned fiber preparations contracting isometrically were shifted to the left by 0.15-0.20 pCa units in the presence of 50 microM pimobendan. In contrast, there was no effect of pimobendan on the ATPase activity of unloaded myofibrillar preparations. The stimulation of force and ATPase activity of the skinned heart muscle fibers could be accounted for by an effect of pimobendan on the affinity of the regulatory (low affinity, Ca2+-specific) binding sites of cardiac troponin C. Ca2+ binding to the "structural" high affinity sites of troponin C was slightly inhibited. The results indicate that the positive inotropic actions of pimobendan, but not milrinone, may involve activation of the cardiac myofilaments by a direct effect involving an increased affinity of the regulatory site on troponin C for Ca2+.

Actin Cytoskeleton↗
PubMed1988

Differential effects of d- and l-pimobendan on cardiac myofilament calcium sensitivity.

The effects is of the optical isomers of pimobendan (UD-CG 115 BS), an inotropic agent, were studied on the electrical and mechanical activity of intact and detergent-skinned preparations of cardiac muscle from guinea pig and dog. Racemic pimobendan has been shown to increase contractile force and to potentiate slow action potentials (AP) induced by stimulation of papillary muscle partially depolarized with 25 mM [K]o. These effects are shown in this study to be mainly due to the l-optical isomer of pimobendan. When slow APs were maximally stimulated by 1 microM isoproterenol, addition of either the d- or l-isomer of pimobendan did not affect the slow AP parameters. However, under these conditions, contractile force was significantly increased to 124% of control by the d-isomer and to 184% of control by the l-isomer. These results suggest that pimobendan may have direct effects on the myofilaments and that these effects are dependent on the optical isomer of the compound. To test this directly, the effects of d- and l-pimobendan were compared on Ca++-activated force developed by detergent-skinned heart muscle fibers. Submaximal force developed at constant Ca++ was increased by both optical isomers, but the l-isomer had a significantly greater Ca++-sensitizing effect. For example at pCa 6.75 force was 270% of control in the presence of the d-isomer and 400% of control in the presence of the l-isomer. At pCa 5, there was no effect of either isomer on force developed by the skinned fiber preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗
PubMed1987

The nature of ventricular arrhythmias during ergonovine-induced vasospastic angina pectoris.

The peak incidence of ventricular fibrillation in acute myocardial infarction usually occurs during the first hours after the onset. Electrophysiological changes immediately after the onset have been studied in animal models, but are still incompletely understood in humans. For clarification of the characteristic features of ventricular arrhythmias during acute myocardial ischemia, ventricular arrhythmias were studied in 81 patients with vasospastic angina pectoris induced by ergonovine. Ventricular arrhythmias occurred in 45 of these patients, including ventricular tachycardia in 15, and ventricular fibrillation requiring repeated DC defibrillation in two patients. Most ventricular extrasystoles occurred before the ST segment reached maximum elevation, while reperfusion arrhythmias were less common. In many patients the coupling intervals varied, and the configuration was multiform. It is concluded that ventricular arrhythmias occurring during ergonovine-induced coronary spasm show different characteristics from those occurring during chronic ischemia. As the arrhythmias in this study seem, in some ways, to resemble arrhythmias occurring at the onset of myocardial infarction, the results might provide useful information on ventricular arrhythmias in myocardial ischemia in humans.

Angina Pectoris, Variant↗
PubMed1987

Vector U loop in patients with right ventricular overloading.

The U loop of the vectorcardiogram (VCG) was examined qualitatively and quantitatively in 126 normal subjects, 15 subjects with complete right bundle branch block (CRBBB group) and 58 patients with right ventricular overloading (RVO group), using a direct-writing vectorcardiograph with memory function. In normal subjects the U loop was directed similarly to the T loop, i.e., to the left, anteriorly and inferiorly. In the CRBBB group, maximum U vector was smaller, but its direction was not significantly different from that in normal subjects. In the RVO group, the U loop tended to be displaced posteriorly and to the left and was significantly greater in magnitude than that in normal subjects in the horizontal (P less than 0.01) and frontal (P less than 0.001) planes. In the RVO group, a good correlation was found between the direction of maximum U vector and right ventricular systolic pressure. In some cases of the RVO group, the U loop was the only abnormality suggesting right ventricular overloading. These findings suggest that abnormality of the U loop is a good indicator in a diagnosis of right ventricular overloading.

Adolescent↗
PubMed1987

[Experimental study of intraneural circulatory changes in axonal de- and regeneration].

Two experimental studies were made of intraneural circulatory change on axonal de- and regeneration using median and ulnar nerves of the Japanese monkey. Experiment 1: Epineural suture was performed on one side, and fascicular suture was performed on the opposite side by removing the interfascicular epineurium. The regenerated axons in the fascicular suture group were fewer in number and smaller in diameter than those in the epineural suture group; this may have been the result of destruction of the interfascicular epineurium. Experiment 2: Inter- and intrafascicular blood circulation was investigated by the electric hydrogen ion gas clearance method with the following results. Blocking of a segment of the blood supply over a length of more than 20 times the nerve diameter caused circulatory disturbance of the intrafascicular blood flow and secondary axonal degeneration. Irreversible intrafascicular blood circulatory disturbance was caused by stripping of the intrafascicular epineurium. In served segments with preserved segmental blood vessels, longer segments preserved more intraneural blood flow than shorter ones.

Animals↗