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Biomedical subjects

C Kondo

Publications and source records attributed to C Kondo.

At least 19 recordsLinked to original sources
PubMed1992

Pulmonary hypertension: pulmonary flow quantification and flow profile analysis with velocity-encoded cine MR imaging.

Velocity-encoded cine magnetic resonance (MR) imaging provides two-dimensional velocity maps of a cross-sectional area of a vessel. Pulmonary flow and flow patterns in the main pulmonary artery were analyzed with velocity-encoded cine MR imaging and Doppler echocardiography in 10 patients with pulmonary hypertension (PH), one patient with a dilated main pulmonary artery, and 10 healthy subjects, and these findings were compared. Peak systolic velocity measured with velocity-encoded cine MR imaging was similar to that measured with Doppler echocardiography in healthy subjects and in patients with PH. Velocity-encoded cine MR imaging demonstrated substantial differences in velocity across the vascular lumen in PH. The flow pattern in healthy subjects was different than that in patients with PH; the latter had lower peak systolic velocity and greater retrograde flow after middle to late systole. The retrograde flow observed in patients with PH reflected hemodynamic events, since it was inversely proportional to pulmonary flow volume and directly proportional to pulmonary resistance and cross-sectional area of the vessel. Velocity-encoded cine MR imaging demonstrates an inhomogeneous flow profile in PH and may serve as a noninvasive method to estimate pulmonary vascular resistance.

Adult↗
PubMed1992

[Influence of family history over several generations on schizophrenic patients--study of a special type of stem family where a husband is found for the heiress].

Family histories over several generations were studied, since it was considered that these might have various influences on the descendants, We hypothesized that poor home management policy by the parental generation would have greater influence on the onset of schizophrenia in the offsprings, and later their social adjustment. To test this theory, twenty families of a special type, called "mukotori-kazoku" in Japanese, which literally means a family that takes in a husband for the sole heiress in the absence of a male heir, were chosen; ten of these families had a schizophrenic patient (schizophrenic group) and the other ten did not (control group). In this type of stem family, the husband (bridegroom) changes his family name to that of the wife and lives with the wife's family, to whom he is generally obliged to devote himself. Such a "mukotori-kazoku" tends to be run mainly in order to preserve or develop the family, and thus provides a good model for investigation of home management policy. Before presenting the results of this study, our former findings should be mentioned. We found that there tends to be a cycle in the family history over several generations consisting of three periods: a period of destruction, a period of reconstruction and a period of stability. All of the schizophrenic patients we studied previously became ill as the cycle was approaching the period of stability. The results of the present study were as follows. In the schizophrenic group on the maternal side, there was always a period of destruction during the great-grandparents' and/or grandparents' generation. Most of the patients' mothers (heiresses) were forced to devote themselves to family reconstruction and had married unwillingly. Similarly, in the former generation on the paternal side, a period of destruction was often observed. Most of the patients' fathers had been treated as a nuisance in their family or origin, and had been obliged to marry out of the family, and/or they had considered that marriage was the easiest path to economic independence. The patients' family members were so indifferent to the father that he became isolated within the family.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1991

Nuclear magnetic resonance imaging of the palliative operation for hypoplastic left heart syndrome.

Electrocardiographic-gated nuclear magnetic resonance (NMR) imaging has been shown to be effective for the evaluation of congenital heart disease, particularly in supracardiac regions. This study evaluated the postoperative status after a stage I palliative operation (Norwood procedure) for hypoplastic left heart syndrome. The NMR images from three patients were compared with those of angiography and depicted all components of the reconstructed supracardiac and intracardiac anatomy after this operation. Nonobstructive anastomosis of the main pulmonary artery to the proximal aorta was clearly demonstrated in each patient. The caliber of the central or branch pulmonary artery, patency and caliber of the systemic to pulmonary artery shunt and the size of the atrial communication were also depicted in each patient and these findings corresponded with angiographic results. The results suggest that NMR imaging is effective for assessing the results of initial palliative surgery for hypoplastic left heart syndrome, which seems to be important for managing patients before subsequent definitive surgery.

Anastomosis, Surgical↗
PubMed1991

Right and left lung perfusion: in vitro and in vivo validation with oblique-angle, velocity-encoded cine MR imaging.

Quantification of pulmonary flow is clinically important in the evaluation of both congenital and acquired heart disease. Velocity-encoded cine magnetic resonance (MR) is a promising technique for measuring velocity and volume of blood flow. The authors report validation of the accuracy of velocity-encoded cine MR for measurement of oblique-angle flow in vitro, with use of a constant-flow phantom, and in vivo, with nine healthy volunteers in whom velocities were measured separately in the main, right, and left pulmonary arteries. Findings at MR were compared with findings at Doppler echocardiography. Velocity measurements in a flow phantom with cine MR correlated well with direct measurements at Doppler echocardiography. Velocity-encoded cine MR enabled accurate and reproducible measurement of absolute blood flow in healthy subjects. Oblique-gradient flow encoding (ie, flow-encoding direction coinciding with the true direction of flow) was the method of choice for velocity measurements in the right and left pulmonary arteries.

Adult↗
PubMed1991

Right and left ventricular stroke volume measurements with velocity-encoded cine MR imaging: in vitro and in vivo validation.

The accuracy of measurements of flow velocity determined by using cine MR phase velocity mapping--velocity-encoded cine (VEC) MR--was assessed by comparing VEC MR data with independent measurements in a flow phantom and in human subjects. Constant flow velocities generated in a phantom (range, 20-408 cm/sec) were determined correctly by VEC MR (r = .997, standard error of the estimate [SEE] = 7.9 cm/sec). Peak systolic velocities in the main pulmonary artery determined by VEC MR correlated well with the measurements obtained by using continuous-wave Doppler echocardiography (r = .91). Stroke volumes measured at the aorta by VEC MR and continuous-wave Doppler imaging also correlated well with each other (r = .80). VEC MR measurements of aortic and pulmonary flow provided left and right ventricular stroke volumes that correlated well with left ventricular stroke volumes determined by short-axis cine MR images (r = .98, SEE = 3.7 ml, and r = .95, SEE = 4.8 ml, respectively). Intra- and interobserver variabilities were small for both left and right ventricular stroke volumes as measured with VEC MR. These results indicate that VEC MR accurately and reproducibly measures aortic and pulmonary flow velocities and volumes in the physiologic range of humans, and can be used to measure right and left ventricular stroke volumes under normal flow conditions.

Adult↗
PubMed1991

[Surgical repair of ischemic mitral regurgitation].

We studied surgical results of 14 cases of ischemic mitral regurgitation. There was no surgical death in 10 cases with left ventricular aneurysm, and their clinical symptoms improved except 3 with the combined operation of left ventricular aneurysmectomy, mitral annuloplasty and bypass grafting. The range of the abnormal contracting segment significantly decreased after surgery except in 3 cases in whom clinical status was not improved. Three of 4 cases which underwent bypass grafting and mitral annulo-valvuloplasty survived, but one of them died of graft-versus-host disease. In the three survived cases, severe mitral regurgitation disappeared. We have concluded as follows: In cases of left ventricular aneurysm, a sufficient aneurysmal resection is very important to control the mitral regurgitation, and the additional procedures of mitral annuloplasty and bypass grafting are essential. The mitral valve replacement is recommended in case of the complete disruption of the papillary muscle. Mitral valvuloplasty combined with annuloplasty is suitable to control the regurgitation in the regional mitral prolapse due to the torn chordae.

Adult↗
PubMed1991

Evaluation of valvular heart disease with cine gradient echo magnetic resonance imaging.

Electrocardiographic referenced repetitive gradient echo magnetic resonance imaging (cine GRE) has been used to detect and quantify valvular regurgitation. Regurgitation is recognized as a signal void in the high intensity blood pool on these images. Mitral regurgitation causes a signal void in the left atrium in systole, and aortic regurgitation produces one in the left ventricle in diastole. The specificity, sensitivity, and diagnostic accuracy of cine GRE for the detection of mitral and aortic regurgitation was greater than 0.93, 0.89, and 0.92, respectively. The severity of regurgitation has been quantified as the difference in the stroke volume between the two ventricles by measuring the volume of the blood pool, as shown in the stack of magnetic resonance tomograms. Severity has also been assessed by measuring the volume of the signal void. Finally, measurements of the volume of aortic regurgitation have recently been achieved by using velocity-encoded cine GRE. This technique provides a direct measurement of retrograde flow in the aorta during diastole. New cine GRE imaging techniques provide a noninvasive means for quantification of valvular as well as ventricular function.

Aortic Valve↗
PubMed1990

Normal left ventricular dimensions and function: interstudy reproducibility of measurements with cine MR imaging.

The authors evaluated the reproducibility of measurements of ventricular dimensions obtained with cine magnetic resonance (MR) imaging performed on two occasions in 11 healthy subjects. Two reviewers analyzed the studies in a blinded fashion to determine interobserver and interstudy variability of measurements of left ventricular (LV) mass, volume, ejection fraction, and systolic wall stress. LV mass showed good reproducibility between studies, with 3.6% and 3.8% variability for LV end-systolic mass for the two observers. LV end-diastolic volume varied by 5.2% and 3.9%, and LV end-systolic volume, by 9.7% and 0.9%. Variability for LV ejection fraction was 5.0% and 4.9%. The largest interstudy variability was end-systolic wall stress, 11.1% and 13.5%, which was due mostly to changes in arterial pressure between the two studies. It is concluded that anatomic and functional measurements from cine MR images are reproducible between studies. The small interstudy variability is likely related to the fact the measurements are derived directly from cine MR images that encompass the entire heart rather than depend on measurements of only sample images and the use of geometric models.

Adult↗
PubMed1990

Determination of left ventricular volume and mass with use of biphasic spin-echo MR imaging: comparison with cine MR.

In this study, the authors compared a new rapid spin-echo magnetic resonance (MR) imaging method, biphasic MR, with cine MR in the determination of left ventricular volume and mass in healthy volunteers. Biphasic spin-echo MR images covering the entire heart were obtained with use of the electrocardiogram R wave and the downslope of the T wave at both end diastole and end systole, respectively. Biphasic MR-determined values correlated well with small standard errors of the estimate (end-diastolic volume = 7.82 cm3, end-diastolic mass = 10.20 g, end-systolic mass = 10.08 g, ejection fraction = 2.62%) and were more reproducible. Cine MR-defined end-systolic volume was significantly larger (P less than .01) and ejection fraction was significantly smaller (P less than .005) than biphasic MR-determined values probably because of the uncertainty in isolating end systole with cine MR. Left ventricular volumes, mass, and ejection fraction are more accurately and reproducibly quantified in a more time-efficient manner with use of biphasic MR than with cine MR because of its significantly shorter image acquisition and reconstruction times.

Adult↗
PubMed1990

Evaluation of surgical procedures for cyanotic congenital heart disease by using MR imaging.

ECG-gated MR imaging has been shown to be effective for the diagnosis of congenital heart disease. In this study, we assessed its role in the postoperative evaluation of surgical procedures in patients with complex congenital heart disease. MR images of 26 patients with Rastelli (five), Fontan (three), Senning (three), Damus (one), Jatene (eight), Waterston (four), and Potts (two) procedures were evaluated retrospectively. The accuracy of MR imaging was compared with that of angiography in 20 patients. The surgical anastomoses were identified in all patients. Patency, atresia, or hypoplasia of central pulmonary arteries and postoperative complications (focal stenoses of pulmonary arteries, thrombosed conduit, peri-conduit abscess) were shown. Narrowing of the right ventricular outflow tract and focal compression of the proximal pulmonary arteries were recognized as specific complications of the Jatene procedure. MR imaging appears to be effective in the postoperative evaluation of surgical procedures used for congenital heart disease. It should be considered as an alternative to repeated catheterization and angiography for the postoperative examination of children with complex congenital heart disease.

Adolescent↗
PubMed1990

Cine MR imaging of valvular heart disease: display and imaging parameters affect the size of the signal void caused by valvular regurgitation.

The effects of display and imaging parameters on the measured size of the signal void representing valvular regurgitation on cine MR imaging were examined. Sixteen patients with valvular regurgitation were studied. Six cine acquisition modes were evaluated in five patients. Echo times (TEs) (8, 12, and 17 msec) and flip angles (30 degrees and 50 degrees) were varied. The variable display parameters were [Z x (blood pool signal intensity - lung signal intensity)] at window width (Z = 0.75, 1.00, 1.25) and (Y x window width + lung signal intensity) at window level (Y = 0.00, 0.25, 0.50). The area of the signal void was significantly (p less than .01) affected by the window level (2.7 +/- 0.8 cm2 at Y = 0.00, 4.4 +/- 1.1 cm2 at Y = 0.25, and 5.6 +/- 1.4 cm2 at Y = 0.50) and window width (3.6 +/- 0.9 cm2 at Z = 0.75 and 4.9 +/- 1.1 cm2 at Z = 1.25). With standardized display parameters, TE influenced the area (3.3 +/- 1.1 cm2 at 8 msec and 7.8 +/- 1.5 cm2 at 12 msec; p less than .01). Variations in the value of TE and display settings cause differences in the measured area of the regurgitant signal void. Quantification of valvular regurgitation by cine MR imaging requires strict standardization of display and imaging parameters.

Adult↗
PubMed1989

The complete sequence of the rice (Oryza sativa) chloroplast genome: intermolecular recombination between distinct tRNA genes accounts for a major plastid DNA inversion during the evolution of the cereals.

The entire chloroplast genome of the monocot rice (Oryza sativa) has been sequenced and comprises 134525 bp. Predicted genes have been identified along with open reading frames (ORFs) conserved between rice and the previously sequenced chloroplast genomes, a dicot, tobacco (Nicotiana tabacum), and a liverwort (Marchantia polymorpha). The same complement of 30 tRNA and 4 rRNA genes has been conserved between rice and tobacco. Most ORFs extensively conserved between N. tabacum and M. polymorpha are also conserved intact in rice. However, several such ORFs are entirely absent in rice, or present only in severely truncated form. Structural changes are also apparent in the genome relative to tobacco. The inverted repeats, characteristic of chloroplast genome structure, have expanded outward to include several genes present only once per genome in tobacco and liverwort and the large single copy region has undergone a series of inversions which predate the divergence of the cereals. A chimeric tRNA pseudogene overlaps an apparent endpoint of the largest inversion, and a model invoking illegitimate recombination between tRNA genes is proposed which accounts simultaneously for the origin of this pseudogene, the large inversion and the creation of repeated sequences near the inversion endpoints.

Amino Acid Sequence↗
PubMed1989

Lung aeration and lung water dynamics in artificially ventilated newborn lambs.

To the present lung liquid dynamics in the immediate neonatal period have been measured mainly by gravimetric techniques. This paper explores lung aeration and lung water dynamics in seven fetal lambs between 139 and 142 days of gestation delivered by caesarean section and ventilated on a constant-volume respirator. After caesarean section and instrumentation, fetal lambs were quickly transferred to a warm X-ray table and connected to a volume-cycled respirator. X-ray fluoroscopic images of the chest commenced before the first breath and were recorded on video tape. After 1 h of ventilation, measurements were made of pulmonary blood volume, and lung samples were taken for wet weight and dry weight analysis. Fluoroscopic image brightness was calibrated by comparison with images obtained from a water wedge, which extended across the X-ray field. Thus image brightness was related to "equivalent water path length" through the thorax. Within a defined lung field, image brightness increases as the amount of lung water in the path of the X-ray beam is reduced. This occurs rapidly at first and then more slowly over the remaining hour. There was considerable variation between the reduction of liquid in the lung fields examined within the one animal, as well as the absolute amount of fluid that had been cleared during the 1st h.

Animals↗
PubMed1989

Measurement of lung water dynamics and lung aeration in the perinatal period by use of digital X-ray fluoroscopy.

A method has been developed for the measurement of lung water dynamics and regional aeration of the lung in anesthetized newborn lambs by use of X-ray fluoroscopy, video recording, and digital image processing. After cesarean section and before the first breath fetal lambs under halothane-oxygen were placed on an X-ray table and connected to a volume-cycled respirator. X-ray fluoroscopy commenced before the initiation of respiration, and the images were recorded on video tape. X-ray transmission through the thorax increased as the lung was aerated. The enhanced transmission was compared with the values obtained from a calibration water wedge from which an equivalent path length through water can be estimated. In testing this method, it was demonstrated that X-ray transmission was linearly related to the wet lung weight-to-body weight ratio and to the product of the wet-to-dry weight ratio multiplied by anatomic thickness of frozen lung blocks. Calibrated values were also linearly related to this product and to the actual measured height of the fluid and tissue in the fluid-filled lung.

Animals↗
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↗
PubMed1978

Visual evoked potentials during hypothermia and prolonged circulatory arrest.

Visual evoked potentials were recorded in eight children during hypothermia and circulatory arrest. The potentials were lost in all children recorded in late arrest. The evoked potential is a more sensitive indicator of CNS stress as provoked by combined hypothermia and hypoxia than is the EEG. EEG activity persisted in six of the eight children in this series even during circulatory arrest. The EEG had been seen to do the same in more than half of a larger series of children recorded at that stage. The results suggest that evoked potentials may be a sensitive indicator of early impairment of cerebral function and may demonstrate useful change sooner than the EEG. The examination may be useful in following children with illnesses producing hypoxia or anoxia. The N1 component was as easily and as frequently identifiable as the P2 component. Under the stress of this procedure, the latency of the P2 component became more variable than the N1 peak. The results suggest the N1 component may be as useful and perhaps more useful than the P2 wave in following the effect of some CNS stresses in children.

Cardiac Surgical Procedures↗
PubMed1978

Studies on the QRS wave of the spatial magnitude electrocardiogram in ventricular septal defect.

The QRS wave of the spatial magnitude electrocardiogram (ECG) was investigated in 86 cases of the ventricular septal defect (VSD). The relationship between the amplitude and the time interval of QRS wave of the spatial magnitude ECG and the various hemodynamic parameters obtained by the right heart catheterization and the defect area ascertained during the operations were evaluated.

Adolescent↗