Search PubMed⌕ Search

Biomedical subjects

C Kondo

Publications and source records attributed to C Kondo.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1988

Atrial natriuretic peptide production in association with nonimmune fetal hydrops.

The presence and elevation of atrial natriuretic peptide in fetuses has not previously been demonstrated. This study of right atrial pacing in fetal lambs demonstrated a threefold to fourfold increase in atrial natriuretic peptide during the production of fetal hydrops. Its rate of return to a normal level paralleled the clearance of fetal hydrops. Its possible role in fetal cardiovascular hemodynamics is discussed.

Animals↗
PubMed1988

Single breath airway occlusion measurements of compliance and resistance utilizing a mechanical ventilator.

A simple manipulation of the outflow valve of a Baby Bird MKII ventilator was used to measure passive lung mechanics by the airway occlusion technique. The results showed satisfactory reproducibility and comparison with other techniques at intra and interstudy level. This technique may have important clinical ramifications as it allows measurements of passive lung mechanics to be made without the need for cumbersome valves or handling of the airway. This convenience could also allow for concomitant plethysmographic lung volume assessments.

Airway Resistance↗
PubMed1988

The synthesis, cloning and expression of a repeating segment of the circumsporozoite surface protein of Plasmodium falciparum.

Repeats of the tetrapeptide (NANP) of the circumsporozoite protein of P. falciparum have been found to be immunogenic and possibly may act as vaccines against malaria infection. The DNA duplex encoding for eight of the (NANP) repeating unit and two of the (NVDP) unit have been synthesized, cloned and expressed in E. coli as a fused protein. The recombinant protein was shown to be immunogenic and to have the antigenic activity of the circumsporozoite.

Amino Acid Sequence↗
PubMed1987

Ultrasound evaluation of tachycardia-induced hydrops in the fetal lamb.

Nonimmune hydrops was induced in six fetal lambs at 120 days' gestation by right atrial pacing at 300 beats/min. Biochemical, hemodynamic, and Doppler parameters were observed and monitored by real-time ultrasound during the creation (18 to 42 hours) and resolution of hydrops. The significant changes seen were hypoproteinemia (34.3 to 29.0 mg/100 ml), venous hypertension (24.6 to 31.3 mm Hg), decreases in thoracic aorta flow, and decreases in systolic/diastolic ratios in the aorta and umbilical artery. These changes were reversed with the discontinuation of pacing and the resolution of fetal hydrops.

Animals↗
PubMed1987

Mitral regurgitation in Kawasaki disease.

The clinical characteristics and prognosis of 16 cases of mitral regurgitation (MR) secondary to Kawasaki disease (KD) were studied, and its pathogenesis was discussed. The observation period ranged from 3 years and 17 months to 15 years. Six of the 16 patients died, and 10 are alive. MR has disappeared spontaneously in 2 of these survivors. Thirteen of the 16 patients were male and 3 were female, there being a predominance in male, which is a striking contrast to rheumatic mitral regurgitation which is predominant in females. The age at the time of diagnosis ranged from 3 months to 7 years. The appearance time of MR showed two different patterns, one with early onset within a few weeks to one month after affliction with KD and the other with MR developing months or years later during the course of the follow-up. The cardiothoracic ratio was greater in those who had a progressively downhill course, and whose sigma RV1-6 decreased with time course. This was considered to be due to the decrease of the remaining functioning myocardial mass. The outcome of the patients with a severe degree of coronary arterial stenosis and occlusion observed on the coronary angiogram was poor. The prognosis of the patients with severe left coronary arterial stenosis was especially poor. MR due to KD is regarded as a new clinical entity, and its pathogenesis is thought to be due to ischemia, papillary muscle dysfunction, coronary angitis, myocardial failure and valvulitis. Incidence of MR will increase when examined by Doppler echocardiography especially in the acute stage. Our experience as well as that of others indicates the presence of valvulitis, myocarditis or left ventricular dilatation leading to MR in the acute stage.

Child↗