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Biomedical subjects

H Takayasu

Publications and source records attributed to H Takayasu.

At least 19 recordsLinked to original sources
PubMed1992

[Surgical treatment of coarctation of the aorta].

Repair of coarctation of the aorta was performed in 37 cases (31 patients, 6 patients of reoperation) ranging from 4 days old to 15 years old. Subclavian flap repair were performed in 15, resection and end-to-end anastomosis in 14, patch aortoplasty in 6, and interposition graft in 2. Subclavian flap angioplasty or end-to-end anastomosis is considered the procedure of choice in infants. However, the incidence of reoperation significantly increased in patients younger than age one month at initial subclavian flap repair. Mechanism of recurrent coarctation may be possibly related to retention of abnormal tissue, which is possibly ductal and/or intimal shelf, with the potential for proliferation and luminal narrowing. We suggest that in applicable case end-to-end anastomosis rather than subclavian flap angioplasty may be the surgical technique of choice in infants less than one month of age, and the most common reoperation technique was patch aortoplasty in re-stenosed cases.

Adolescent↗
PubMed1991

IL-2 and IL-5 both induce mu S and J chain mRNA in a clonal B cell line, but differ in their cell-cycle dependency for optimal signaling.

We have found that a neoplastic Lyl+ B cell clone (BCL1-3B3) can be stimulated to secrete IgM by a Th1-derived cytokine, IL-2, and/or by a Th2-derived cytokine, IL-5. At suboptimal concentrations these interleukins acted synergistically to enhance IgM secretion. Both IL-2 and IL-5 induced increases in microseconds and J chain mRNA levels. In the presence of both ILs, increases in microseconds and J chain mRNA were additive and paralleled increases in IgM secretion. Using cells synchronized at the G1/S border with excess thymidine or in early G1 using isoleucine-deficient media, IL-2 and IL-5 differed in their cell-cycle dependency for signal transmission. IL-5 appeared to act preferentially in late G1 of the cell cycle. In contrast, IL-2 stimulated S and G2 phase cells slightly more efficiently than cells in G1 of the cell cycle. Furthermore, a twofold increase in high-affinity IL-2R was observed as the cells entered S phase. The results suggest that although IL-2 and IL-5 can independently and additively induce differentiation of the Lyl+ BCL1-3B3 cells, they differ in their point of action during the cell cycle.

Animals↗
PubMed1991

[Successful repair of TGA with ventricular septal defect, the outflow tract stenosis of the left ventricle and coarctation of the aortic arch].

A 9-month-old boy after the coarctectomy at 5 months old was successfully repaired by Senning procedure with closure of ventricular septal defect and resection of the membranous septal aneurysm causing the outflow tract stenosis of the left ventricle. Retrospectively, this case might have been possible to do Jatene procedure, however, attempts to resect the left ventricular outflow tract stenosis often failed to relieve stenosis completely. Therefore, the intraatrial switch operation seems to be better than the arterial switch operation when there is a possibility to remain left ventricular outflow tract stenosis. True estimation for these cases must await more case studies.

Aorta, Thoracic↗
PubMed1990

Characterization of a neoplastic B cell clone that secretes IgM in response to Th2-derived lymphokines.

Recent advances of T cell cloning have allowed the classification of T helper cells in terms of the lymphokines they secrete. The functional significance of segregating lymphokine production to unique T cell subsets is still being evaluated, but undoubtedly plays a key role in the regulatory mechanisms of the immune system. Initial studies have indicated that the Th1 cells which secrete IL-2 and IFN-gamma may be primarily responsible for augmenting cell-mediated responses, whereas Th2 cells, which release IL-4, IL-5, and IL-6, provide help for humoral responses. However, it is also known that B cells can respond to both IL-2 and IFN-gamma. This raises the question of the homogeneity of B lymphocyte activation requirements. Are all B cells responsive to all of the lymphokines with the end-result of stimulation depending largely on the relative concentrations of the various lymphokines, or are there B cell subsets which only respond to Th1-derived lymphokines and others which respond to Th2-derived lymphokines? Such differential activation requirements might be present to allow these subsets to play unique roles in immunological responses. Since B cell cloning techniques have not yet been developed to obtain a homogenous B cell population for studies of activation requirements, regulation of lymphokine receptors, and regulation of gene expression, we must utilize lymphokine-responsive neoplastic B cells. The vast majority of spontaneous B cell lymphomas appear to belong to a minor B cell subset which expresses the Ly1 marker. This subset is clearly not representative of the majority of splenic B cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Development and experimental investigation of an ultrasound myocardial stimulator for clinical application].

Recently there has been considerable experiments on biological and clinical application of ultrasound. However, the effect of ultrasound on cardiac function has not been fully understood. We have already reported the effect of the ultrasound myocardial stimulation (U.M.S.) in isolated rat heart. This study was undertaken to examine the potentiality of U.M.S. in clinical application. Twenty four mongrel dogs were divided into four groups, group I: ultrasound was irradiated in front half of the reperfusion time, group II: it was irradiated in last half of the reperfusion time group III: it was irradiated fully during the reperfusion time, group IV: it was not irradiated. The stimulator has the intensity of 1.5 W/cm2 in group I, II 0.1 W/cm2 in group III at the frequency of 1.23 MHz continuous wave, during early systolic phase (200 msec.) for twenty minutes. The right heart bypass model was used in the constant mean aortic pressure (75 mmHg) and rate (120 beats/min). The change in left ventricular function was defined as percent of control in the center of mass of Sarnoff curve. The change in end-diastolic, end-systolic segmental length and % shortening were measured. The result of left ventricular function recovery rate were follows, 74.9 +/- 9.13% in group I, 61.0 +/- 8.95% in group II, 78.7 +/- 14.1% in group III, 58.4 +/- 13.5% in group IV in measurement 1 (twenty minutes after reperfusion), and 77.6 +/- 9.45% in group I, 86.7 +/- 8.85% in group II, 86.8 +/- 16.3% in group III, 64.8 +/- 10.6% in group IV in measurement 2 (fifty minutes after reperfusion), indicating that U.M.S. had a significantly better recovery rates. As for end-diastolic, end-systolic segmental length and % shortening, the group that ultrasound was irradiated had a significantly better recovery in both measurement 1 and 2. CPK flow levels per minutes at 15, 35 minutes after reperfusion were significantly lower in the group receiving U.M.S. (p less than 0.05). Lactate extraction were higher in the group receiving U.M.S. at 35 and 45 minutes after reperfusion (p less than 0.05). Redox potential at 45 minutes after reperfusion were also found to be significantly higher in the group receiving U.M.S. (p less than 0.01). In conclusion, 1) U.M.S. possesses positive inotropic action. 2) U.M.S. also effective in preventing the occurrence of myocardial damage. 3) Myocardial metabolism was more aerobic in the group receiving U.M.S. particularly in group III (0.1 W/cm2). 4) These data indicated that U.M.S. has the potentiality in clinical application.

Animals↗
PubMed1989

Cloning and characterization of mammalian homologs of the Drosophila dunce+ gene.

A probe representing the Drosophila dunce+ (dnc+) gene, the structural gene for a cAMP phosphodiesterase (PDEase), detects homologous sequences in many different organisms, including mouse, rat, and human. Genomic and cDNA clones representing a homolog of the Drosophila dnc+ gene were isolated from rat libraries and characterized. This gene has been named ratdnc-1. One cDNA clone defines a large open reading frame of approximately 1.8 kilobases (kb), predicting a protein sequence of 610 amino acids with significant homology to a conserved domain of approximately 275 residues found in most other PDEases. The amino acid identity value to the Drosophila cAMP PDEase within this domain is a striking 75%. Other cDNA clones show blocks of sequence divergence from this cDNA clone close to the predicted N terminus, indicating the potential existence of a family of related enzymes encoded by alternatively spliced messenger RNAs from ratdnc-1. Genomic blotting experiments suggest the existence of at least one other rat gene with homology to ratdnc-1. RNAs homologous to ratdnc-1 are heterogeneous in size between tissues, with heart containing a major transcript of 4.4 kb and brain one of 4.0 kb. The potential identity of the product of the ratdnc-1 gene with known PDEases is discussed.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1988

Flexible ureterorenoscopy.

The clinical applications of flexible ureterorenoscopes have fallen behind those of their rigid counterparts. Flexible endoscopes that possess a working channel and can also be employed for treatment have at last been developed. This instrument is particularly effective in the treatment of stones in the upper urinary tract, as it can easily follow mobile upper ureteral stones and calculi in the middle or lower renal calices, which are not as accessible with a rigid endoscope. It is important to remember not to exert too much force when inserting the instrument into the ureter, renal pelvis, or renal calices, and, if one remains calm, should the visual field become temporarily obscured, there should be little danger of damaging these structures. This method will probably be increasingly employed, not only for the treatment of stones in the upper urinary tract, but also for the removal of foreign bodies and the diagnosis and treatment of small pathologic conditions or lesions such as carcinoma in situ in which the roentgenologic presentation is unclear. For this expansion of instrument use to be ensured, it is necessary to improve the resolution of the fiberoptic endoscope image and increase the instrument's angulation capabilities, increase the range of accessories that can be employed with it, and also increase familiarity with the instruments on the part of urologists.

Endoscopes↗
PubMed1988

A case of spontaneous esophageal rupture treated with conservative therapy.

A 51 year-old male was admitted because of abrupt hematemesis and loss of consciousness. Emergency endoscopy depicted a giant esophageal ulcer on the left side extending from the middle intrathoracic region to the lower intrathoracic region. Esophagography, performed on the second day of admission, revealed a huge cavity (10 cm x 7 cm) filled with contrast medium resulting from a rupture in the ulceration. His state of shock improved with conservative therapy and no severe mediastinitis was noted. The drainage from the cavity into the lumen of the esophagus was considered to be acceptable from esophagography and an endoscopic examination. Secondary to his stable condition and continuous drainage, this patient was treated conservatively throughout his clinical course. The patient was given intravenous hyperalimentation (IVH) until the 25th hospital day and was medicated with broad spectrum-antibiotics. On the 21st hospital day the size of the esophageal cavity was markedly decreased (7 cm x 2 cm). Only small irregular mucosa was noted on the esophagogram taken 6 weeks after admission. Six months after the onset, an X-ray examination revealed complete healing of the spontaneous esophageal rupture with no recurrence.

Anti-Bacterial Agents↗