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Biomedical subjects

S Nagata

Publications and source records attributed to S Nagata.

At least 703 records · Page 39Linked to original sources
PubMed1983

Mitral regurgitation in hypertrophic cardiomyopathy. Non-invasive study by two dimensional Doppler echocardiography.

Mitral regurgitation and its haemodynamic features were investigated non-invasively in cases of hypertrophic cardiomyopathy by means of two dimensional Doppler echocardiography. There were 28 patients, 14 of whom showed systolic anterior motion (SAM) of the mitral echo; the other 14 did not. The following results were obtained. (1) Mitral regurgitation was detected by the Doppler technique in all cases with systolic anterior motion of the mitral echo and in half of those without it. (2) Doppler signals of mitral regurgitation started immediately after the first heart sound. (3) Mitral regurgitant flow was often distributed from the entire mitral orifice over the entire or the posterior half of the left atrium in the cases with systolic anterior motion. In the cases without systolic anterior motion the regurgitation was usually localised near the mitral orifice. These features differ from those of regurgitation usually seen in rheumatic mitral valve disease and idiopathic mitral valve prolapse. (4) The Doppler technique and left ventriculography were equally efficient in detecting mitral regurgitation. (5) The early systolic component of the murmur of hypertrophic myopathy is considered to result in the main from concomitant mitral regurgitation, but not from turbulent blood flow in the left ventricular outflow tract, so that in cases with mitral regurgitation as a complication, mitral regurgitation may also contribute to the development of the midsystolic portion of the systolic murmur, while the main origin of this portion of the murmur is the left ventricular outflow obstruction.

Adult↗
PubMed1983

Supravalvular aortic stenosis and coronary ostial stenosis in familial hypercholesterolemia: two-dimensional echocardiographic assessment.

The lesions of the aortic root, which are supravalvular aortic stenosis and coronary ostial stenosis, in familial hypercholesterolemia were studied using two-dimensional echocardiography. The subjects were 25 heterozygotes, six homozygotes and 30 control subjects. The internal diameters of the aortic ring, the sinus of Valsalva and the supravalvular aortic ring were measured. Measurement variation due to body size was avoided by normalizing the latter two values by the diameter of the aortic ring. Four heterozygotes and all homozygotes were judged to have stenosis of the supravalvular aortic ring; none of heterozygotes and four homozygotes had stenosis of the sinus of Valsalva. In three of the four patients with stenosis of both the supravalvular aortic ring and the sinus of Valsalva, a pressure gradient was demonstrated. The degree of supravalvular aortic stenosis correlated with the serum cholesterol level but not with patient age. All homozygotes, even very young ones, had a severe aortic root lesion. In the short-axis view of the aortic root, a lump (raised mass) on the aortic wall indicating atheromatous plaquing was demonstrated in five heterozygotes and all homozygotes. Coronary ostial stenosis was shown in three of the four patients whose plaquing echoes were adjacent to the coronary orifice. We conclude that two-dimensional echocardiography is useful in diagnosing lesions of the aortic root in patients with hypercholesterolemia.

Adolescent↗
PubMed1983

Chaotic echo motion in the left ventricular cavity. Visualization of ruptured chordae tendineae of the mitral valve by real-time two-dimensional echocardiography.

The aim of the present study is to perform a detailed analysis of the spot echoes which show chaotic motion of the left ventricular cavity of patients with ruptured chordae tendineae. The subjects were 12 patients with surgically documented ruptured chordae tendineae. They were carefully examined preoperatively by real-time two-dimensional echocardiography with a commercially available wide-angle phased array system (Toshiba SSH-11A). An abnormal moving spot echo was often seen instantaneously in the left ventricle. Its motion was chaotic, and it moved both longitudinally and laterally. Lateral movements were seen in 10 of the 12 subjects and were not found in any of 10 controls. The site of this echo in the left ventricle was identical with the site of the rupture of the mitral chordae confirmed during surgery. Therefore, it was concluded that the spot echo with chaotic motion represents a direct visualization of ruptured chordae. This chaotic motion is considered to be a useful clue in diagnosis. The lateral component (left to right) of the movement is especially important. However, one must carefully examine the left ventricular cavity with moving pictures over a period of many heart beats in order to detect these chaotic movements of spot echoes.

Adolescent↗
PubMed1983

Combination chemotherapy in retroperitoneal poorly differentiated myxoid liposarcoma: a report of a case.

We describe a case of a 47-year-old man with retroperitoneal poorly differentiated myxoid liposarcoma. The retroperitoneal invasion of the sarcoma caused hydroureter-nephrosis, rectal stenosis and also exaggerated steroid induced diabetes mellitus. A remarkable regression was achieved by systemic combination of chemotherapy with prednisolone, cyclophosphamide, vincristine sulfate and actinomycin D. This combination chemotherapy is worth trying if a patient has inoperable liposarcoma. It can also be used to reduce local recurrence rate after surgical or radiation therapy, or both, against liposarcoma.

Antineoplastic Agents↗
PubMed1983

[Diastolic filling of the right ventricle in hypertrophic cardiomyopathy studied with 2-dimensional Doppler echocardiography].

Inflow pattern at the tricuspid orifice was examined using two-dimensional Doppler echocardiography. The cases examined consisted of 24 cases of hypertrophic cardiomyopathy (HCM), 10 cases of left ventricular hypertrophy (LVH) due to hypertension or aortic valvular stenosis and 23 healthy subjects. The right ventricular inflow pattern in HCM was characterized by a slow deceleration of a rapid filling wave, an increase in the duration of an inflow due to atrial contraction and an increased ratio of the peak velocity in atrial contraction phase to that in rapid filling phase (A/R). No definite difference was noted in the right ventricular inflow pattern between HCM with and without left ventricular obstruction. The abnormalities in the right ventricular inflow pattern in LVH were similar to those in HCM. The abnormal inflow patterns in HCM and LVH suggested a reduced distensibility of the right ventricle in early diastole and the compensatory augmentation of right atrial contraction. The changes in the deceleration of the rapid filling wave and A/R ratio were significantly correlated with interventricular septal thickness (base and papillary muscle levels) in cases with LVH. This result seemed to indicate that the changes in the right ventricular inflow are mainly resulted from the influence of hypertrophy of the interventricular septum on right ventricular function. There was hypertrophy of the interventricular septum in all cases of HCM and, in addition, that of the right ventricular anterior wall in some of them. The changes in the inflow pattern in HCM are also considered to be resulted from hypertrophy of the right ventricular anterior wall and the influence of hypertrophy of the interventricular septum on right ventricular function. However, in the cases of HCM, the extent of the changes showed no significant correlation with right ventricular anterior wall thickness and interventricular septal thickness. In HCM, hypertrophy of the interventricular septum and right ventricular free wall may coexist, and ventricular hypertrophy is often nonuniform and may exhibit disarrangement in myocardial architecture. Therefore, influential factors on the right ventricular inflow are considered to be more complicated in HCM than in LVH, resulting in the absence of significant correlation to the abnormal inflow mentioned above.

Adolescent↗
PubMed1982

Structure and expression of human IFN-alpha genes.

Copy DNA (cDNA) was prepared from induced leucocyte poly(A) RNA and cloned in Escherichia coli. IFN-alpha cDNA clones were isolated by subculture cloning with the use of a translation hybridization assay. Definitive identification of the clones was based on the production of an interferon-like protein by the transformed bacteria. Different IFN-alpha cDNAs, with characteristic target cell specificities, were identified. The cloned cDNAs typically encode a mature polypeptide of 166 (or, for IFN-alpha 2, 165) amino acids and a signal sequence of 23 amino acids. A human chromosomal library was screened with IFN cDNA and 17 distinct IFN-alpha-related sequences were isolated and identified, of which 7 proved to be nonallelic authentic genes and 4 pseudogenes; 6 sequences remain to be elucidated. Taking into account the work of Goeddel and his colleagues, 13 non-allelic authentic genes and 6 pseudogenes can be distinguished. In addition, 9 genes believed to be allelic to the 13 authentic genes have been sequenced. The IFN-alpha genes may be classified into two major subfamilies, which diverged at least 33 Ma ago, but perhaps much earlier, if sequence rectification occurred. At least one IFN-alpha gene appears to have resulted by a recombinational event between members of the subfamily I and II. IFN-beta is distantly related to IFN-alpha's and may have diverged from a common ancestor at least 500 Ma ago. Both IFN-alpha and IFN-beta genes differ from most other genes of higher organisms by being devoid of introns. The mouse was found to possess an IFN-alpha gene family of a size similar to that of man; the murine genes also do not have introns. IFN-alpha genes devoid of their signal sequence were joined to prokaryotic promoters to produce the mature interferons in E. coli in high yield. IFN-alpha 2, purified to homogeneity, has been crystallized by T. Unge and B. Strandberg (Uppsala). Hybrid genes consisting of IFN-alpha 1 and IFN-alpha 2 segments were constructed and expressed in E. coli; the target cell specificities of such hybrids were dependent on the arrangement of the segments and were different from those of either parent. The chromosomal gene for HuIFN-alpha 1 was introduced into mouse L cells to study the mechanism of its expression. Correct transcription was only detected after induction (with Newcastle disease virus); expression was transient, with the same kinetics as those of the endogenous mouse IFN mRNA. Natural murine IFNs and human IFN-beta and IFN-gamma are glycosylated. Because E. coli cells transformed with the genes of eukaryotic glycoproteins are not expected to yield correctly glycosylated polypeptides, we prepared lines of hamster cells permanently transformed with hybrid plasmids, which contained an IFN gene linked to the SV40 early promoter, as well as dihydrofolate reductase as a selective marker. After intracellular amplification of the introduced genes, cell lines were obtained which constitutively produced IFN at about 40 000 units ml-1 and could be propagated for at least several months.

Base Sequence↗
PubMed1982

Chromosomal location of a human alpha interferon gene family.

To determine the chromosomal location of the human alpha interferon genes, we scored a series of human/rodent somatic cell hybrids for the presence of DNA sequences hybridizing to an alpha 1 interferon DNA probe. The presence of human chromosome 9 in a hybrid correlated with the presence of a family of alpha interferon genes.

Animals↗
PubMed1982

Echocardiographic study of abnormal position and motion of the posterobasal wall of the left ventricle in cases of giant left atrium.

In 35 of 70 patients with rheumatic mitral valve disease, two dimensional echocardiography revealed the posterobasal wall of the left ventricle to be entrapped between the left ventricular and atrial cavities and bent inward. The motion of the bending segment was paradoxical. This abnormality was assumed to be induced by the left atrial dilatation extending inferiorly behind the left ventricle, because the length of the bending segment correlation with the left atrial dimension. There was no correlation between the degree of abnormal bending and left atrial pressure, mitral valve pressure gradient or left ventricular dimension. The systolic excursion of the posterobasal wall of the left ventricle was reduced according to the length of the bending segment. This abnormal feature was also observed in five postmortem heart specimens with an extremely dilated left atrium. The macroscopic and microscopic findings in the myocardium of the bending segment were not different from those of the remaining segment of the left ventricle. Therefore, the asynergic motion of the bending segment is assumed to be caused by the abnormal spatial orientation of the left ventricle and the left atrium. It should be considered that the giant left atrium not only oppresses the surrounding organs but also affects the left ventricle.

Adult↗
PubMed1982

Effect of ventricular hypertrophy on conduction velocity of activation front in the ventricular myocardium.

To study the effect of ventricular hypertrophy on conduction velocity of the activation front noninvasively, transmural conduction indexes were obtained from findings of echocardiography and body surface potential mapping performed in 40 patients with right bundle branch block uncomplicated by the left anterior fascicular block. Because in these patients, left ventricular activation proceeds radially without being modified by right ventricular activation, the index was obtained by dividing ventricular septal thickness measured from the echocardiogram by transmural conduction time, which was taken as the time interval from the onset of the QRS complex to the time when the left ventricular epicardial breakthrough minimum appeared on the potential map. The indexes, ranging from 11 to 45 cm/s, has a good positive linear correlation with the septal thickness (Y = 2.37X - 1.33, correlation coefficient [r] = 0.83) and were abnormally small in some failed hearts. Further, both the mean ventricular activation times in lead V5 and the mean value for total duration of left ventricular activation did not differ significantly in patients with and without left ventricular hypertrophy. These findings suggest that conduction velocity was increased in the hypertrophied ventricle and decreased in the failed hearts. Because there were no significant differences in the mean serum sodium and potassium concentrations in the patients with and without left ventricular hypertrophy, it is concluded that hypertrophy itself most likely caused greater conduction velocity. Enlarged cells and multiple intercalated discs abundant in hypertrophied ventricle would have facilitated intercellular current flow and, hence, conduction velocity and impaired cellular connection in the failed heart would have reduced them. Thus, the transmural conduction index is suggested to be an important aid in interpreting electrocardiograms as well as in estimating the pathologic state of the heart.

Adolescent↗
PubMed1982

Thymocyte precursors in early-thymectomized Xenopus: migration into and differentiation in allogenic thymus grafts.

In an anuran amphibian, Xenopus laevis, thymectomy of 4-day-old larvae abrogates T-cell dependent immune responsiveness. When such early-thymectomized (TX) diploid frogs were implanted with histocompatible triploid thymuses and grafted 8 weeks later with skin from third-party donors, the grafts were rejected relatively normally in 20-27 days. Microspectrophotometric determination of ploidy 3-5 months after thymus reconstitution revealed that most thymocytes were donor-derived. In contrast, when TX frogs received allogeneic triploid thymuses, they rejected skin grafts from a third-party donor relatively slowly (48-92 days) but did not reject skin from the thymus donor. Most thymocytes in such animals were of host origin. Host thymocytes were present 4 weeks after thymus implantation and became dominant population by 12 weeks. Few thymus implant-derived donor cells were detectable in the host spleen. These data suggest that existence of precursor cells in TX Xenopus that can functionally differentiate along a T-cell pathway as a result of microenvironment provided by the thymus implant.

Animals↗
PubMed1982

Localisation and direction of mitral regurgitant flow in mitral orifice studied with combined use of ultrasonic pulsed Doppler technique and two dimensional echocardiography.

Regurgitant flow was analysed in 40 cases of mitral regurgitation, using combined ultrasonic pulsed Doppler technique and two dimensional echocardiography. Abnormal Doppler signals indicative of mitral regurgitant flow were detected in reference to the two dimensional image of the long axis view of the heart and the short axis view at the level of the mitral orifice. The overall direction of regurgitant flow into the left atrium was clearly seen in 28 of 40 cases, and the localisation of regurgitant flow in the mitral orifice in 38 cases. In cases with mitral valve prolapse of the anterior leaflet or posterior leaflet the regurgitant flow was directed posteriorly or anteriorly, respectively. The prolapse occurred at the anterolateral commissure or posteromedial commissure and resulted in regurgitant flow located near the anterolateral commissure or posteromedial commissure of the mitral orifice, respectively. In cases with rheumatic mitral regurgitation the regurgitant flow is usually towards the central portion of the left atrium and is sited in the mid-part of the orifice. The Doppler findings were consistent with left ventriculography and surgical findings. The ultrasonic pulsed Doppler technique combined with two dimensional echocardiography is useful for non-invasive analysis and preoperative assessment of mitral regurgitation.

Adult↗
PubMed1982

Psychosomatic aspects of skin diseases from the standpoint of immunology.

The psychosomatic aspects of skin disease were studied both clinically and experimentally, from the standpoint of immunology. We found that emotional stress has a great influence on the immune system, as was manifested in skin disease. Skin test in allergic patients significantly improved with autogenic training and relaxation. For clarification of the effects of autogenic training and relaxation, various parameters were simultaneously assessed during the treatment. The serum levels of histamine and dopamine-beta-hydroxylase fluctuated, as determined by the microvibration test. The levels of IgE and findings on the PK test varied only slightly. Before the onset of urticaria, there were changes in the life-style and considerable stress in daily life as well as exposure to an allergen. Using mice subjected to stress, the functions of T cells and macrophages were evaluated. Stress appeared to have a definite influence on the functions of these cells, as related to the important role of the immune system and skin. Thus, the role of stress in clinical disease must always be given consideration.

Adult↗
PubMed1982

Pulmonary regurgitation studied with the ultrasonic pulsed Doppler technique.

Sixty patients with pulmonary regurgitation were studied by the pulsed Doppler technique combined with two-dimensional and M-mode echocardiography. Patients with pulmonary regurgitation had abnormal Doppler signals just below the pulmonic valve in the right ventricular outflow tract in diastole on the two-dimensional image. These signals were considered to indicate the regurgitant flow. There are two patterns of pulmonary regurgitant Doppler signals. In pulmonary hypertension, the maximal component of instantaneous flow velocity is sustained at about the same signal strength throughout diastole, but when the pulmonary arterial pressure is normal, the velocity slows down gradually from early diastole to end-diastole. Pulmonary regurgitation was detected by phonocardiography in about half the patients. In the remaining half, pulmonary regurgitant murmur could not be differentiated from aortic regurgitant murmur or was masked by coexistent aortic regurgitation or patent ductus arteriosus, whereas the Doppler technique indicated pulmonary regurgitation.

Adolescent↗
PubMed1982

Idiopathic mitral valve prolapse-analysis by real-time two-dimensional echocardiography.

Mitral valve prolapse is diagnosed in real-time two-dimensional echocardiograms when there are discrepancies in the coaptation zone of the anterior mitral leaflet and the posterior mitral leaflet. Out of the 100 cases of mitral valve prolapse diagnosed in this way, 65 had prolapsed anterior mitral leaflets, 28 prolapsed posterior mitral leaflets and 7 prolapses of both the anterior and posterior mitral leaflets. In addition to the cases with mitral valve prolapse 23 cases of ruptured chordae tendineae of the mitral valve, including 15 cases which had undergone surgery, were investigated. The frequent site of mitral valve prolapse was the posteromedial commissure in the anterior leaflet and the posteromedial and anterolateral commissures in the posterior leaflet. These sites coincide with those where rupture of the chordae tendineae of the mitral valve was apt to occur. An investigation of the relation between age and mitral valve prolapse showed that the number of cases of prolapsed anterior leaflet did not increase with age, but there was an age-related increase in the number of cases of prolapsed posterior leaflets. It was also found that the degree of the prolapse progressed with age. Many of the cases of ruptured chordae tendineae of the mitral valve were in their forties or fifties, and there appeared to be some relation between the progress of the prolapse and age. Mitral regurgitant murmurs were recorded on phonocardiograms, and the severer the degree, the wider the range of the prolapse. Mitral regurgitation was more likely to occur in cases of prolapsed posterior leaflets than in those with prolapsed anterior leaflets, even if the degree and the range of the prolapse were mild.

Adolescent↗