Biomedical subjects

A Takao

Publications and source records attributed to A Takao.

At least 109 records · Page 6Linked to original sources

PubMed1989

Detection of coronary artery stenosis in children with Kawasaki disease. Usefulness of pharmacologic stress 201Tl myocardial tomography.

This study determined the feasibility and accuracy of quantitative 201Tl myocardial single-photon emission computed tomography (SPECT) after dipyridamole infusion to detect coronary obstructive lesions in children with Kawasaki disease. 201Tl distribution after dipyridamole infusion was measured in 23 normal children, and with these normal values, quantitative analysis of SPECT was performed in 49 patients. Thirty-four patients had coronary stenosis 90% or greater on angiograms. Side effects resulting from systemic vasodilation were observed in about 70%. Angina pectoris and ischemic ST changes were observed only in patients with coronary stenosis. These symptoms disappeared after aminophylline infusion. Results of visual and quantitative analysis of SPECT were compared. SPECT data were shown on two-dimensional polar maps, and the extent and severity scores were calculated. The sensitivity of SPECT for detection of overall coronary stenosis was 91% (visual analysis) and 88% (quantitative analysis). The specificity of SPECT was 60% visually and 93% quantitatively. The sensitivity of quantitative analysis to detect individual coronary stenosis was similar to that of visual analysis. However, the specificity of visual analysis to detect individual coronary artery stenosis was significantly less than that of quantitative analysis. From these data, we conclude that quantitative analysis of myocardial SPECT after dipyridamole infusion is a safe and accurate diagnostic method for identifying coronary stenosis in children with Kawasaki disease.

Adolescent↗

PubMed1989

Right ventricular concentric hypertrophy and left ventricular dilatation by ductal constriction in fetal rats.

Fetal cardiac changes due to ductal constriction by maternal ingestion of nonsteroidal anti-inflammatory drugs were studied morphologically in near-term rats as an animal model, and results were compared with values of control 1 (C1, twenty-first day) and control 2 (C2, twenty-second day). The fetal ductus was constricted (-70%) (p less than 0.05) by maternal administration of 10 mg/kg indomethacin. Dilatation of the right ventricle and evidence of congestive heart failure including increased pericardial effusion (+200%) (p less than 0.05) and an increase in water content in the abdominal wall were present at 1, 4, and 8 hours after drug administration. At 24 hours after drug administration, concentric right ventricular hypertrophy was shown by a diminished right ventricular cavity (-36% vs. C2) (p less than 0.05), increased right ventricular wall thickness (+70% vs. C2) (p less than 0.05), and increased right ventricular mass (+31% vs. C1) (p less than 0.05). Left ventricular dilatation was indicated by an increased cavity volume (+87% vs. C2) (p less than 0.05) and increased muscle mass (+29% vs. C1 [p less than 0.05] or +9% vs. C2 [p greater than 0.05]). Both the wet and dry weights of the ventricles were increased. In conclusion, fetal ductal constriction caused right ventricular hypertrophy, diminished right ventricular cavity, and left ventricular dilatation and hypertrophy at 24 hours after drug administration in rats after initial congestive failure.

Animals↗

PubMed1989

Increased constriction of the ductus arteriosus with combined administration of indomethacin and betamethasone in fetal rats.

To find a better treatment for patient ductus arteriosus of preterm infants, we studied the combined effect of indomethacin and betamethasone on the fetal ductus in rats. We used a rapid whole-body freezing technique, and the ratio of the inner diameter of the ductus to the main pulmonary artery, which was 1.0 in controls, was used as an index of constriction. Indices of ductal constriction 4 h after administration of indomethacin (1 mg/kg) alone, betamethasone (1 mg/kg) alone or in combination in near-term rats were 0.56 +/- 0.05 (mean +/- SEM), 0.76 +/- 0.06, and 0.17 +/- 0.03, respectively. In preterm rats too, a marked increase in fetal ductus constriction was observed with the combined administration of these two drugs. Study of the dose effect of betamethasone revealed that maximal effects were obtained with 1 mg/kg of betamethasone combined with indomethacin in both preterm and near-term fetal rats. Increased constriction of the fetal ductus with combination treatment persisted from 1 to 8 h after administration. Administration of betamethasone 24 h before the rat was killed did not augment constriction of the fetal ductus by indomethacin administered 4 h before they were killed. Fetal ductus constriction by sulindac, another nonsteroidal antiinflammatory drug with little inhibitory effect on renal function, also was augmented by combined use with betamethasone (1 mg/kg). In conclusion, ductal constriction was markedly increased by combined administration of indomethacin and betamethasone in near-term and preterm fetal rats.

Animals↗

PubMed1989

Fetal cardiovascular effects of nifedipine in rats.

In this study we clarify the fetal cardiovascular effects of nifedipine. Nifedipine was administered to near-term rats and cardiovascular morphology of the fetus was studied with a rapid whole-body freezing technique. Fetal cardiac failure was estimated by accumulation of pericardial effusion and ventricular dilatation. Dose-response study at 8 h after administration revealed that slight ventricular dilatation occurred with 0.1 mg/kg of nifedipine, and remarkable ventricular dilatation and pericardial fluid accumulation were noted with 10 mg/kg nifedipine. Time-course study with one dose of 10 mg/kg nifedipine revealed early ventricular dilatation at 1 h, peak ventricular dilatation and fluid accumulation at 8 h, and slight effects at 24 h. In conclusion, the cardiodepressive effect of nifedipine in the fetal rat was mild with the therapeutic dose, and its effects increased dose dependently.

Animals↗

PubMed1989

[Pharmacokinetics of new cisplatin analogues in experimental animals].

An equi-toxic dose of CDDP and its analogues (254-S, NK-121, CBDCA and DWA-2114 R) was administered to rabbits and S.180 bearing mice, and the pharmacokinetics were studied. Blood levels: Plasma total platinum (Pt) curves of 5 drugs decreased, showing a biphasic function. The shortest t 1/2 alpha and the longest t 1/2 beta were observed in CDDP group, which correlated with the rate of protein binding (CDDP greater than DWA-2114R greater than NK-121 greater than CBDCA greater than 254-S). Tissue distribution: The tissue levels of Pt decreased slowly, and showed a similar pattern among 5 drugs. The highest level was observed in the kidney, liver and skin, with a moderate high level in the tumor, lung, spleen and thymus, followed by the heart, pancreas, stomach, intestine, muscle and testis in that order. The lowest level was in the brain in S.180 bearing mice.

Animals↗

PubMed1989

Primary pulmonary hypertension in infancy: report of two autopsy cases.

Two cases of unexplained plexogenic pulmonary arteriopathy in infancy were studied by patho-anatomical approach. The patients were boys, age 7 months and 2 years 2 months. Pulmonary arteries revealed Grade 3 and Grade 4 hypertensive changes, respectively, after Heath and Edwards' criteria. The configuration of the media of the pulmonary trunk suggested that though these cases were very young, pulmonary arterial pressure had been elevated since some time after birth.

Aorta↗

PubMed1988

Development of the myocardial contractile system.

Recent studies regarding developmental changes in the myocardial contractile system from fetal, newborn, and adult animals are reviewed. From the data obtained so far, we conclude that in the early fetus myocardial contraction is mainly dependent on Ca which enters via the sarcolemma. Ca release from the sarcoplasmic reticulum is minimal. The role of the sarcoplasmic reticulum as a source of contractile Ca increases and the role of Ca influx across the sarcolemma in contractile system decreases with development.

Animals↗

PubMed1988

Molecular cloning and chromosomal localization of a gene coding for human cardiac myosin heavy-chain.

A human cardiac myosin heavy-chain (MHC) gene, cloned in a charon 4A phage, was isolated using two rat cardiac pCMHC DNA clones (pCMHC26: alpha-MHC type; and pCMHC5: beta-MHC type) as probes and shown to correspond to cardiac myosin heavy-chain of the alpha-type. The 4.3-KB cardiac genomic DNA clone was used as a probe in the Southern analysis of human genomic DNA from human-Chinese hamster or human-mouse somatic cell hybrids. The results show that the human cardiac MHC gene is assigned to chromosome 14 and the human cardiac and skeletal MHC genes do not cosegregate as do the mouse cardiac and skeletal MHC genes.

Chromosome Mapping↗

PubMed1988

Cardiovascular anomalies produced by nimustine hydrochloride in the rat fetus.

The cardiovascular teratogenicity of nimustine hydrochloride (ACNU) was studied in rat fetuses. This drug is a nitrosourea derivative anticancer agent and produces alkylation of DNA. Pregnant Donryu rats were treated with single doses of 10, 11 or 13 mg/kg of the teratogen at various stages during gestation. Examination of the hearts was performed by microdissection after sacrificing the animals on the 20th day of gestation. The highest frequency of cardiovascular anomalies was found in the groups treated on the 8th day of gestation, but there was no difference in the rates induced by the three dosages of ACNU administered. The most common cardiovascular anomalies observed were ventricular septal defect (76.8%) and double outlet right ventricle (10.3%). A considerable number of affected fetuses (37/263) showed complex cardiac anomalies with atrioventricular (AV) malalignment and other AV valve anomalies. These anomalies include: double inlet left ventricle, straddling AV valve, atresia or stenosis of the AV valve, and dysplastic AV valve. ACNU appears to be a useful teratogenic agent for inducing complexes of cardiac anomalies which include AV malalignment.

Animals↗

PubMed1988

Hemodynamic characteristics in neural crest cell-excised chick embryo.

Damage to premigratory cranial neural crest cells results in cardiovascular anomalies of so-called conotruncal anomaly. In one report, it was suggested that hemodynamic alteration would precede abnormal cardiovascular morphogenesis. We repeated this hemodynamic study in neural crest cell-excised chick embryos and found that there was no difference in heart rate and blood pressure between the treated embryos (n = 11; 164 +/- 3 beats per min (BPM) and 0.75 +/- 0.03 mmHg, respectively) and control embryos (n = 7; 160 +/- 6 BPM and 0.72 +/- 0.07 mmHg, respectively). The response of heart rate to acetylcholine was less (P less than 0.05) in the treated embryos (-13% +/- 2%) than in the control (-20% +/- 2%). Thus, the present data do not support the hypothesis that alterations in blood pressure and heart rate are causally related to abnormal cardiovascular morphogenesis. The developmental significance of subtle functional changes in neural crest-extirpated embryos in response to cholinergic challenge is unclear.

Animals↗

PubMed1988

Left ventricular characteristics during exercise in patients after Fontan's operation for tricuspid atresia.

Left ventricular function during supine bicycle exercise was studied using multigated blood pool imaging in ten patients with tricuspid atresia after Fontan's operation and in 13 children and adults (control group). The mean age of the patients was 16 years and the mean interval between operation and study was 5 years. The peak work loads that the patients could perform were similar to those in the control group. Work loads and heart rates during radionuclide study in the operated group were also similar to those in the control group. The left ventricular ejection fraction at rest and during exercise in the operated group was less than in the control group, although the net increase during exercise was similar in the two groups. During exercise, left ventricular end-diastolic volume decreased significantly in the operated group. In the control group, this variable did not change significantly. Left ventricular stroke volume increased during exercise in the control group but it did not change significantly in the operated group. These data indicate that in patients after Fontan's operation, left ventricular performance remains low during exercise, which is in part due to diminished left ventricular preload reserve, and this in turn may be caused by reduced reserve of right heart output.

Adolescent↗

PubMed1988

ECG findings after myocardial infarction in children after Kawasaki disease.

Standard 12-lead ECGs were evaluated in 17 children with myocardial infarction and 78 children without myocardial infarction after Kawasaki disease; sensitivity and specificity of the ECG infarction criteria were determined. The presence or absence of myocardial infarction was determined from either clinical examination results (coronary angiography, ventriculography, and thallium-201 myocardial imaging) or autopsy findings. Of seven patients with inferior infarction, abnormally deep Q waves in lead II, III, or aVF were observed in six, but the duration was greater than 0.04 second in only one (14%). The sensitivity and specificity of inferior infarction criteria based on Q wave amplitude were 86% and 97%, respectively. Of eight patients with anterior infarction, seven (88%) had abnormally deep and wide (greater than or equal to 0.04 second) Q waves in anterior chest leads. The sensitivity and specificity of the infarction criteria based on the amplitude and duration of the Q wave were 75% and 99%, respectively. Of seven patients with lateral infarction, Q waves were observed in lead I, aVL, or both in four patients, and in all of these patients Q waves were wider than 0.04 second. In two patients with both inferior and anterior infarction, Q waves were observed only in leads II, III, and aVF; in only one patient were the Q waves wider than 0.04 second. Thus deep Q waves in lead II, III, or aVF that are not wider than 0.04 second may indicate inferior infarction in children. Q waves in lead I, aVL, and chest leads associated with anterolateral infarction are in most instances deep and wide.

Child↗

PubMed1988

Objective evaluation of differences in patterns of EEG topographical maps by Mahalanobis distance.

The purpose of this work was to develop a method to objectively evaluate differences in topographical patterns between 2 groups of isopotential maps. Previous evaluations by other investigators had been based on subjective judgment which created problems in describing differences in patterns, particularly when the differences were subtle. In the method presented in this report, the differences are evaluated by the Mahalanobis distance calculated from polynomial coefficient vectors obtained from unbiased polynomial interpolation in order to calculate values of picture elements in the 2-dimensional maps. One polynomial coefficient vector corresponds to one pattern of the map, containing both EEG and locational information. Examples of the evaluation are shown in the maps of fast activities induced by the injection of thiopental, diazepam or both drugs to an adult volunteer. In 5 experimental situations (A, control; B, thiopental; C, thiopental and diazepam; D, diazepam; and E, diazepam and thiopental administration), the polynomial coefficient vectors were obtained. When Mahalanobis distances (Q value) between the 2 maps for the 5 situations, arranged in 8 different combinations, were calculated, the values corresponded significantly to the pattern differences found between the maps. The greater the Q value, the more dominant the pattern difference. The objective evaluation method presented in this report has significant advantages over the subjective method previously reported and should be of interest to investigators attempting to quantify topographical pattern differences.

Adult↗

PubMed1988

Conotruncal repair of tetralogy of Fallot.

A repair within the conotruncal portion of the right ventricle is introduced. It was used for the intracardiac repair of 30 consecutive patients with tetralogy of Fallot. The infundibular septum was totally resected to reduce the muscular outflow stenosis. Short patch infundibuloplasty with a large monocusp was then used. Instead of the tricuspid septal leaflet, the membranous flap was employed as the suture line for patching the ventricular septal defect (VSD) to avoid a conduction disturbance, residual VSD, and fixing of the tricuspid septal leaflet. The right ventricular (RV) to systemic arterial pressure ratio was 50.0 +/- 14.6% (N = 26) and right atrial pressure was 9.0 +/- 2.5 mm Hg (N = 26) one month after operation. RV end-diastolic volume was 93.0 +/- 30.5% of normal (N = 15) before operation and 96.7 +/- 29.0% of normal one month after operation in the same patients. These data suggest that a conotruncal repair can maintain good RV function with low right atrial pressure and with no increase of RV volume.

Child↗

PubMed1988

Potentiating effects of verapamil on cardiovascular teratogenicity of phenobarbital in the chick embryos.

Teratogenic to subteratogenic doses of phenobarbital were administered to young chick embryos together with a calcium-blocking agent, verapamil, at doses where it alone induces no cardiovascular malformations. The cardiovascular teratogenicity of phenobarbital was significantly potentiated by verapamil (5 X 10(-11), 1 X 10(-10) mol). The alteration of calcium movement into the cell and/or depressed cardiac function following impaired calcium transport by verapamil are suggested as modus operandi in the potentiation of phenobarbital-induced cardiovascular malformations.

Abnormalities, Drug-Induced↗

PubMed1988

Criteria for two-staged arterial switch operation for simple transposition of great arteries.

We analyzed hemodynamic variables in patients with transposition of the great arteries with intact ventricular septum (simple transposition) after pulmonary artery banding and Blalock-Taussig anastomosis to establish the criteria for two-staged arterial switch operation. The study included 35 patients who underwent the switch operation after banding and anastomosis; two died shortly after surgery, and one died of tachycardia 31 days after the operation. The left-to-right ventricular pressure ratio was above 0.83 in all surviving patients, 0.68 and 0.63 in the two operative deaths, and 0.84 in the other death. In the 32 surviving patients, angiographically determined left ventricular (LV) end-diastolic volume and ejection fraction averaged 147 +/- 46(SD)% of normal and 0.64 +/- 0.12, respectively. We also measured LV mass using angiographic LV semiaxes and end-diastolic LV posterior wall thickness obtained from an echocardiogram. These variables of the patients who died were not different from those of the surviving patients. The wall thickness was greater than 4 mm in the surviving patients, while it was 3.5 mm in the two patients who died early and 5 mm in the patient who died later. From the semiaxes, the wall thickness, and aortic diastolic pressure, all of which were obtained before the anatomic repair, we calculated the predictive LV wall stress. This wall stress would indicate the LV wall stress at the time of aortic valve opening immediately after the arterial switch operation. Predictive wall stress was less than 120 x 10(3) dynes/cm2 in all but one of the surviving patients, whereas it was 151, 153, and 186 x 10(3) dynes/cm2 in the three patients who died.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗

PubMed1988

Developmental hemodynamic changes in rat embryos at 11 to 15 days of gestation: normal data of blood pressure and the effect of caffeine compared to data from chick embryo.

We attempted to measure arterial blood pressure of the rat embryo. The embryo was excised within the uterus and immersed in Hanks' solution at 37 degrees C. The uterus wall and yolk sac were opened to expose the umbilical vessels. The umbilical artery was punctured with a glass micro-pipette, and blood pressure was measured by using a servo-null micro-pressure system. The mean blood pressure was 0.27 +/- 0.05 mm Hg in the embryo at the 11th day of gestation (n = 7), 0.48 +/- 0.03 mm Hg in the 12-day embryos (n = 19), 1.3 +/- 0.08 mm Hg in the 13-day (n = 11), and 2.6 +/- 0.1 mm Hg in the 15-day embryos (n = 10). Heart rate was 84 +/- 11 in 11-day, 122 +/- 3 in 12-day, 192 +/- 7 in 13-day, and 198 +/- 5 in 15-day embryos. These parameters were stable within 10 min after the excision. A comparison of the data with those of the chick embryo of comparable developmental stages revealed that the blood pressure was lower in 11- and 12-day rat embryos than in the chick embryo of Hamburger-Hamilton stages 18 and 21, but this was reversed in the later stages. In the stage 21 chick embryo, intravenous administration of caffeine (60 +/- 9 mg/kg embryo weight) induced an increase in blood pressure by 11 +/- 3% (n = 8), but did not result in a significant increase in dorsal aortic blood flow (6 +/- 6%, n = 9) or in heart rate. In contrast, caffeine (62 +/- 3 mg/kg) increased the heart rate by 8 +/- 2% (n = 10) without changing the blood pressure in the rat embryo of day 12. The velocity of blood flow in the truncus was measured by a pulsed Doppler flowmeter. Caffeine injection increased the mean velocity by 21 +/- 8%). Herein we indicate that measurement of blood pressure in the rat embryo is feasible, but with some limitations, and that there may be qualitative hemodynamic differences between the rat and chick embryos.

Animals↗

PubMed1988

Changes in left ventricular dimensions after pulmonary artery banding and Jatene operation in children with complete transposition of the great arteries. Echocardiographic study.

Echocardiographic left ventricular (LV) dimensions in patients with complete transposition of the great arteries (TGA's) were measured before and after the Jatene procedure and/or pulmonary artery banding (PAB). The LV posterior wall thickness at end-diastole (LVPWTD) increased from 3.5 +/- 0.4 to 4.9 +/- 0.9 mm (mean +/- 1SD) (p less than 0.01) after PAB, but it did not show a significant change following the Jatene procedure (from 4.5 +/- 1.0 to 5.3 +/- 0.8 mm). The LV end-diastolic internal dimension (LVIDD) increased from 17.7 +/- 4.0 to 22.6 +/- 6.5 mm after PAB (p less than 0.01), but remained unchanged after the Jatene procedure (from 24.5 +/- 5.0 to 25.0 +/- 3.0 mm). The LV shortening fraction (LVSF) decreased from 0.62 +/- 0.10 to 0.47 +/- 0.14 after PAB (p less than 0.01), but remained unchanged after the Jatene procedure (0.40 +/- 0.10 to 0.37 +/- 0.10). the a/b ratio at end-systole: (a/b)s, which indicates the flatness of the LV configuration, increased from 0.27 +/- 0.14 to 0.60 +/- 0.21 after PAB (p less than 0.01) and from 0.61 +/- 0.13 to 0.74 +/- 0.17 after the Jatene procedure (p less than 0.01). The data obtained became stable 1 month after operation. One patient died of low cardiac output with no evidence of myocardial infarction after the Jatene procedure. In this patient, LVPWTD was 5.7 mm, LVIDD was 26 mm, LVSF was 0.71 and the (a/b)s ratio was 0.55.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗