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Biomedical subjects

Y Wada

Publications and source records attributed to Y Wada.

At least 955 records · Page 53Linked to original sources
PubMed1986

Fetal hemoglobin variants in 80,000 Japanese neonates: high prevalence of Hb F Yamaguchi (A gamma T 80 Asp----Asn).

A population-based screening of newborns for the structural variants of fetal hemoglobin was carried out in Osaka Prefecture, Japan, by isoelectric focusing of globin chains using dried blood on filter paper. Of 80,000 newborns, 18 had alpha globin variants and 55 had gamma globin variants. The incidence of gamma globin variants (1/1,455) was much higher than that of alpha globin variants (1/4,444). Structural studies were then carried out on the abnormal gamma globins in 36 samples, and revealed that 25 of them were Hb F Yamaguchi (A gamma T 80 Asp----Asn). The prevalence of this variant in Japanese was estimated to be as high as one per 2,100.

Adult↗
PubMed1986

Comparative study of cardiovascular profiles of milrinone and amrinone by use of isolated, blood-perfused dog heart preparations.

The cardiac and coronary vasodilator effects of milrinone and amrinone were compared in isolated, blood-perfused papillary muscle and sinoatrial (SA) node and atrioventricular (AV) node preparations of dogs. Milrinone (0.3-100 nmol) and amrinone (0.01-3 mumol) were administered intra-arterially. Both drugs increased the force of contraction of paced and unpaced papillary muscles and the rate of automaticity of the latter; they increased sinus rate and accelerated AV nodal conduction. However, both drugs were not homogeneously effective on cardiac variables but affected them in the following order: The force of contraction of the ventricular muscle greater than SA nodal automaticity divided by AV nodal conduction greater than ventricular automaticity. In producing these cardiac effects, milrinone was 30-60 times more potent than amrinone. Both drugs increased (coronary) blood flow in all preparations. In this respect milrinone was about ten times more potent than amrinone. As a result, milrinone can be characterized as having almost equal cardiotonic and coronary vasodilatory effects, whereas amrinone is more coronary vasodilatory than cardiotonic. These differences in cardiovascular profile may contribute to their differential salutary mechanisms in the treatment of heart failure. Both drugs induced neither AV nodal tachycardia nor ventricular arrhythmia.

Amrinone↗
PubMed1986

Comparative study of MDL 17043 and MDL 19205, new positive inotropic agents, by use of isolated, blood-perfused dog-heart preparations.

The cardiac and coronary vasodilator effects of MDL 17043 and MDL 19205 were compared in isolated, blood-perfused papillary muscle, sinoatrial (SA) node, and atrioventricular (AV) node preparations of dogs. In these preparations, MDL 17043 (0.01-3 mumol) and MDL 19205 (0.01-3 mumol) were injected intra-arterially. Both drugs increased the force of contraction of papillary muscles paced at a rate of 120 stimuli/min, and a ten-fold increase in dose produced about a 100% increase in the force. The two drugs increased the sinus rate in SA node preparations, and a tenfold increase in dose resulted in about a 12% increase in sinus rate with MDL 17043 and about a 17% increase with MDL 19205. These drugs increased the rate of automaticity of spontaneously beating papillary muscles and also the force of contraction. With a ten-fold increase in dose, the increase in the rate was about 16% for MDL 17043 and about 9% for MDL 19205. No ventricular arrhythmias were produced by either drug. The drugs equally decreased AV conduction time by accelerating AV nodal conduction in AV node preparations whose right atria were paced at a rate of 150 stimuli/min. However, the decrease remained about 5% with a ten-fold increase in dose of both drugs. No AV junctional tachycardia was produced. In all preparations, both drugs increased (coronary) blood flow. In paced papillary muscle preparations a tenfold increase in dose resulted in about a 37% increase in blood flow with MDL 17043 and about a 42% increase with MDL 19205.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Lateral geniculate kindling and long-lasting photosensitivity in cats.

The kindling response of the lateral geniculate body (GL) was compared with that of the amygdala, using cats. Daily electrical stimulation in the GL group led to the generalized tonic-clonic convulsion in most subjects and the resulting state of seizure susceptibility was long-lasting, as in the amygdala group. The kindling response of the GL differed from that of the amygdala in some respects, i.e., rapid kindling, short latency for seizure generalization, a different pattern of behavioral seizure development, and seizure regression during the course of kindling. The effects of photic stimulation with pentylenetetrazol administration were also examined before and after kindling in both groups. This study revealed that the photically induced myoclonus, at times proceeding to the generalized tonic-clonic convulsion, was provoked repeatedly as a result of GL kindling, whereas none of the amygdala-kindled cats showed such marked photosensitivity. These photically induced seizures were invariably observed for at least 4 weeks after GL kindling. Our results suggest that a neural mechanism participating in GL kindling is different from that in amygdala kindling, and that there might be cross-sensitization between seizure susceptibility resulting from GL kindling and photosensitivity.

Amygdala↗
PubMed1986

Effects of allylglycine on photosensitivity in the lateral geniculate-kindled cat.

The effects of DL-allylglycine, an inhibitor of GABA synthesis, on the responses to photic stimulation were studied in the cat kindled in the lateral geniculate body (GL). For 3 to 8 h after the injection of DL-allylglycine at a subconvulsant dose (30 or 40 mg/kg, i.v.), the kindled cat showed a stable level of photosensitivity without any toxic effects and responded with various degrees of myoclonus or a generalized tonic-clonic convulsion when photic stimulation was repeated at hourly intervals. The incidence of photically induced myoclonus reached its plateau during this period. Our results suggest that photosensitivity of the lateral geniculate-kindled cat is related to the modification of GABAergic mechanisms, and that when the GL-kindled cat is pretreated with DL-allylglycine it is a reliable model of photosensitive epilepsy.

Allylglycine↗
PubMed1986

Interactions of endotoxin with cortisol and acute phase proteins in septic shock neonates.

CRP, alpha 1-acid glycoprotein and haptoglobin were studied in 13 septic shock neonates. Endotoxin was recovered from eight infants. Serum cortisol concentration from infants with endotoxemia (917 +/- 596 ng/ml) was significantly higher than that from infants without endotoxemia (398 +/- 239 ng/ml). Serum cortisol correlated well with immature neutrophil counts defined as the unit "band/neutrophil". Increased cortisol level and immature neutrophil counts preceded the elevation of CRP, alpha 1-acid glycoprotein and haptoglobin in four extremely premature neonates. We conclude that positive interactions between endotoxin, cortisol and acute phase protein synthesis are present in the initial period of infection, and delayed acute phase protein synthesis is suspected in extremely premature neonates.

C-Reactive Protein↗
PubMed1986

Immunohistochemical demonstration of papillomavirus antigen in cervical dysplasia and vulvar condyloma.

Biopsies from 30 cases of vulvar condyloma, 460 cases of cervical dysplasia, 30 cases of carcinoma in situ and 75 cases of invasive carcinoma of the cervix were screened for the presence of human papillomavirus (HPV) antigen by means of the peroxidase-antiperoxidase method. Positive reaction for HPV was detected in 14 cases of condyloma and 80 cases of dysplasia as a brown intranuclear precipitate in the superficial layer of the epithelium. None of the cases of carcinoma in situ and invasive cancer were positive for HPV. The mean age of the women with HPV-positive dysplasia was significantly lower than that of the women with HPV-negative dysplasia. Condylomatous dysplasia showed a significantly higher positive rate than did noncondylomatous dysplasia. Cases of condylomatous dysplasia with severe stromal inflammation were negative for HPV more frequently than those with mild stromal inflammation.

Adult↗
PubMed1986

Functional characteristics of intramyocardial capacitance vessels during diastole in the dog.

In order to evaluate the functional characteristics of the intramyocardial capacitance vessels during prolonged diastole, we analyzed the response of coronary vein flow after stepwise changes of coronary artery pressure in anesthetized open-chest dogs by using our newly developed laser Doppler velocimeter with an optical fiber. The peripheral portion of the great cardiac vein was isolated and the optical fiber tip was inserted into the vessel. The left anterior descending coronary artery was cannulated and connected to a reservoir to regulate coronary perfusion pressure. Intracoronary adenosine administration was carried out to avoid any change in coronary vasomotor tone. After 15 seconds of occlusion of the perfusion route, the heart was arrested by pacing-off. Two seconds later, coronary perfusion pressure was increased stepwise to a preset target pressure. This procedure was repeated by changing target pressure at 4 (or 5) different pressure levels (31-105 mm Hg). The great cardiac vein flow became zero due to the cardiac arrest and remained at zero for a moment (dead time) after the initiation of reperfusion. Then the flow reappeared and increased with first order time delay. The presence of dead time indicates the existence of unstressed volume, and the first order time delay represents the product of resistance and capacitance. The unstressed volume with a minimal vasomotor tone for perfusion pressure of 60-90 mm Hg was 5.2 +/- 2.2 ml per 100 g left ventricle, which is comparable to coronary blood flow for several beats. The capacitance at perfusion pressure of 60-90 mm Hg was 0.08 +/- 0.04 ml/mm Hg per 100 g left ventricle, while that at low perfusion pressure (30-50 mm Hg) was 0.14 +/- 0.09 ml/mm Hg per 100 g left ventricle. These results indicate that the intramyocardial capacitance vessels have two functional components, and that the phasic nature of coronary vein flow is solely the result of the myocardial squeezing of the blood in the capacitance vessels.

Animals↗
PubMed1986

Cardiac versus coronary vasodilator actions of isobutylmethylxanthine in dogs: comparison with theophylline.

Cardiac and coronary vasodilator effects of isobutylmethylxanthine (IBMX) and theophylline were compared in isolated, blood-perfused papillary muscle, sino-atrial (SA) node and atrioventricular (AV) node preparations of dogs. IBMX (1 nmol-1 mumol) and theophylline (30 nmol-10 mumol) were injected intra-arterially. In paced papillary muscle preparations, both agents increased the force of contraction. In spontaneously beating papillary muscle preparations, both agents increased the rate of ventricular automaticity. In SA node preparations, both agents increased sinus rate. In AV node preparations, both agents decreased AV conduction time only when they were injected into the artery supplying the AV node. In all preparations, both agents increased coronary blood flow. However, both agents were not homogeneously effective on these cardiovascular variables, but showed selectivity in the following order: Ventricular muscle contraction not equal to coronary blood flow greater than SA nodal automaticity not equal to AV nodal conduction greater than ventricular automaticity. These results indicate that IBMX and theophylline have almost an identical profile in their cardiac and coronary vasodilator effects. The two agents were different in that IBMX was 40-50 times as potent as theophylline in producing these effects. Thus, both agents appeared to express their cardiovascular profiles mainly through inhibition of cyclic AMP phosphodiesterase, although theophylline has been claimed to have additional actions.

1-Methyl-3-isobutylxanthine↗
PubMed1986

Immunohistochemical and electron microscopic demonstration of human papillomavirus in dysplasia of the uterine cervix.

Twenty-five cases of dysplasia of the uterine cervix were studied for the presence of human papillomavirus (HPV) by means of immunohistochemical and electron microscopic techniques. Serial sections of the same histological specimen were examined in each case. HPV was detected in 14 cases by both immunohistochemistry and electron microscopy, while 10 cases were negative with both methods. In only one case, there was a discrepancy in the results derived from these two methods. It was concluded that the relation between HPV infection and cervical dysplasia was confirmed and that immunohistochemical and electron microscopic methods led almost to the same result in detecting HPV in cervical dysplasia.

Female↗
PubMed1986

Comparative study of coronary vasodilator and cardiac effects of nitrendipine by use of isolated, blood-perfused dog heart preparations.

The coronary vasodilator and cardiac effects of 3-ethyl-5-methyl-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl) -3,5-pyridinedicarboxylate (nitrendipine, Bay e 5009) were compared in isolated, blood-perfused sinoatrial (SA) node, atrioventricular (AV) node and papillary muscle preparations of dogs with i.a. administration. In all preparations nitrendipine increased (coronary) blood flow. In SA node preparations nitrendipine reduced sinus rate but the reduction remained only about 13% of the basal value even at the highest dose. The dose estimated to produce a 15% (nearly a half maximum) decrease in sinus rate was about 8 times the dose which doubled coronary blood flow. In AV node preparations nitrendipine prolonged AV conduction time when injected into the artery supplying the AV node but the prolongation remained only about 12% of the basal value even at the highest dose. The dose estimated to produce a 15% (nearly a half maximum) increase in AV conduction time was about 11 times the dose which doubled coronary blood flow. When injected into the artery supplying the His-Purkinje ventricular system of AV node preparations, nitrendipine was entirely ineffective on AV conduction. In paced papillary muscle preparations nitrendipine reduced force of contraction. The reduction, however, remained less than 50% of the basal value even at the highest dose. The dose estimated to reduce force of contraction by half was about 11 times the dose which doubled coronary blood flow. Nitrendipine was entirely ineffective on ventricular beating rate of spontaneously beating papillary muscle preparations. These results indicate that nitrendipine is highly vasoselective, and warrant its high efficacy as an antianginal drug.

Animals↗
PubMed1986

Evaluation of human coronary blood flow with an 80 channel 20 MHz pulsed Doppler velocimeter and zero-cross and Fourier transform methods during cardiac surgery.

To evaluate local blood flow velocities accurately at many sampling points in small vessels, especially in human coronary arteries, we have developed an 80 channel 20 MHz pulsed Doppler velocimeter. Doppler signals from 80 channels are detected by a zero-cross method and a signal from an optional channel is analyzed by a fast-Fourier transform method, both in real time. Basic experiments using a model and animals have demonstrated the accuracy and utility of our method of measurement of blood flow velocity for both nondisturbed and disturbed flow. Velocity waveforms in a native coronary artery beyond a vein bypass graft insertion were measured during cardiac surgery. They showed a diastolic-predominant pattern with a small systolic component. During transient graft occlusion, the waveforms changed to a systolic-predominant pattern in a patient with severe stenosis and to a to-and-fro pattern in a patient with total occlusion. In a patient with severe aortic regurgitation, the coronary arterial velocity waveforms exhibited a systolic-predominant pattern with a broad velocity spectrum. After aortic valve replacement, however, a diastolic-predominant pattern with a narrow spectrum was observed.

Blood Flow Velocity↗