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Biomedical subjects

Y Koga

Publications and source records attributed to Y Koga.

At least 343 records · Page 19Linked to original sources
PubMed1991

Alteration in progression of murine autoimmune disease by treatment with a novel immunomodulator, SM-8849.

The effects of SM-8849 on the development of autoimmune disease in MRL/Mp-1pr/1pr mice were examined. SM-8849 improved survival as well as renal disease, restored the deficits in splenic cell responsiveness to stimulation by mitogens or conventional antigens, and prevented lymphadenopathy and splenomegaly coincident with a decrease in the number of Thy-1+/Lyt-2-/L3T4- cells. SM-8849 also suppressed the production of the B-cell differentiation factor, possibly with a resulting preferential reduction of autoantibodies. In addition, SM-8849 depressed the production of hydrogen peroxide from macrophages. These results suggest that the administration of SM-8849 to a subject with autoimmune diseases can induce immunological improvements with possible clinical effectiveness.

Animals↗
PubMed1991

Accumulation of p60lck in HTLV-I-transformed T cell lines detected by an anti-lck monoclonal antibody, MOL 171.

The lck gene encodes a protein tyrosine kinase of nonreceptor type, p56lck, whose expression occurs almost exclusively in T lymphocytes. MOL 171, an anti-p56lck monoclonal antibody, was produced by using a 25-amino-acid synthetic polypeptide as the antigen, its structure corresponding to the N-terminal region deduced from the lck cDNA sequence. Immunoblot analysis with MOL 171 showed the accumulation of 60 kD form of Lck protein, p60lck, and the decrease of p56lck in human T cell leukemia virus type I (HTLV-I)-transformed T cell lines. Another anti-Lck monoclonal antibody, MOL 294, raised by using a synthetic peptide corresponding to the C-terminal region deduced from the lck cDNA sequence, also detected the accumulation of p60lck in those HTLV-I-transformed T cell lines. The appearance of p60lck with the decrease of p56lck in normal T lymphocytes after stimulation suggested the origin of p60lck in HTLV-I-transformed T cells.

Antibodies, Monoclonal↗
PubMed1991

Atypical coarctation of the abdominal aorta as a cause of acute hypertensive heart failure.

A case of atypical coarctation of the suprarenal aorta with symptoms of acute hypertensive heart failure is reported. A 62-year-old man was admitted because of dyspnea associated with severe hypertension. Chest x ray demonstrated mild pulmonary congestion. Following antihypertensive management, symptoms of congestive heart failure improved. Abdominal computed tomography and digital subtraction angiography undertaken several days later demonstrated a narrowed segment of the suprarenal aorta. Control of hypertension was poor with currently available antihypertensives and a bilateral axillo-femoral bypass operation with artificial grafts was undertaken. Postoperative blood pressure was maintained at a normal level with a small dose of atenolol. The patient had an uneventful hospital course and remains well.

Acute Disease↗
PubMed1991

New noninvasive assessment of regional left ventricular function by digital subtraction angiography without the use of contrast medium.

We have developed a new noninvasive method to evaluate regional left ventricular (LV) function by digital subtraction angiography (DSA) without the use of contrast medium. DSA images of the left ventricle with and without contrast medium were obtained from 35 patients with anterior myocardial infarction (MI) and from 35 control subjects. Using an image-processing computer, regional LV time-density curves were constructed for one cardiac cycle. Regional LV time-density curves obtained from DSA without the use of contrast medium presented a pattern similar to those from intravenous DSA. The amplitude of regional LV time-density curves in patients with MI decreased along with increasing severity of regional wall motion abnormality assessed by conventional left ventriculography. In attempting semi-quantitative evaluation by DSA without the use of contrast medium, the regional wall motion index (RWI) in the 6 segments of the left ventricle was calculated by normalizing segmental density changes to the maximal segmental density changes. When compared with control subjects, patients with MI have significantly lower RWIs in the anterolateral and apical regions. RWI showed a good correlation with the regional ejection fraction (REF) obtained from intravenous contrast DSA (r = 0.83). RWI decreased with increasing severity of regional wall motion abnormality by qualitative analysis in conventional left ventriculography, being consistent with REF. The diagnostic accuracy of RWI therefore seemed to be comparable to that of REF derived from intravenous contrast DSA. These results indicate that computerized analysis of DSA without the use of contrast medium is a valuable noninvasive method for semi-quantitative assessment of regional LV function.

Adult↗
PubMed1991

Norepinephrine inhibits human natural killer cell activity in vitro.

The effect of norepinephrine on human NK cell activity was investigated using a flow cytometry assay. NK cell activity was found to be inhibited by direct addition of norepinephrine to lymphocyte/target cell mixtures in a dose-dependent fashion. This inhibitory effect of norepinephrine was blocked by propranolol but not by atenolol. The results suggest that norepinephrine has a negative influence on NK cell activity and that the effect of norepinephrine is mediated via beta 2-adrenoceptors.

Atenolol↗
PubMed1991

[The effect of oral administration of roxatidine acetate hydrochloride 3 hours prior to the operation on pH and volume of gastric juice].

The effect of roxatidine acetate hydrochloride, administered 3 hours prior to induction of anesthesia, on pH and volume of gastric juice was investigated in preoperative patients. In fifty patients, who were scheduled to undergo elective surgery, 150 mg of roxatidine acetate hydrochloride was administered orally 3 hours before the induction of anesthesia. The volume and pH of gastric juice were measured immediately after the induction of anesthesia. In 46 patients out of fifty, pH of gastric juice was more than 2.5, and its volume was below 25 ml. In another 4 patients, pH of gastric juice was more than 2.5, or its volume below 25 ml. We conclude that, oral administration of 150 mg roxatidine 3 hours preoperatively could be effective for the prevention of an aspiration pneumonitis.

Administration, Oral↗
PubMed1991

[Congenital bronchomalacia of left main bronchus combined with lobar emphysema, pectus excavatum and right aortic arch--a case report].

One-year-old girl was admitted because of recurrent pneumonia and pectus excavatum. Chest X-ray showed hyperlucency at the upper lung field and infiltrated shadow at the lower field of the left lung. Bronchoscopy and bronchograms revealed marked collapse in a long segment of the left main bronchus during expiration. CT scan showed an emphysematous change and a giant bulla of left lung. Angiogram showed right aortic arch. Sternoturnover was performed at 5 years of age for pectus excavatum. After 10 months, left pneumonectomy was performed for bronchomalacia and lobar emphysema. Pathologic findings of the bronchus revealed that the rings were flattened, while the cartilage was microscopically normal.

Aorta, Thoracic↗
PubMed1991

[Growth of the aortic anastomosis in puppies--comparison of monofilament suture materials, whether absorbable or nonabsorbable, and of suture techniques, whether continuous or interrupted].

This study compared the growth of vascular anastomoses performed with either polypropylene or polydioxanone sutures and with either continuous running suture or interrupted suture technique. Primary end-to-end anastomoses of the infrarenal aorta were performed in 38 puppies. Nineteen were performed with 5-0 polypropylene sutures; in ten all sutures were placed in continuous fashion, and in nine in interrupted fashion. The other nineteen were performed with 5-0 polydioxanone sutures; in ten the sutures were placed in continuous fashion, and in nine in interrupted fashion. The animals were subjected to the repeated aortograms at 2, 4, 8 weeks, 6 months and 1 year following operation. Each abdominal aorta was subjected to burst test, and pathological examination. All anastomoses were patent and tolerated burst-test (300 mmHg). Neither aneurysm nor dilatation of anastomotic site was observed. Anastomotic area was significantly smaller and more stenotic in the continuous polypropylene suture group than in other three groups at 8 weeks, 6 months and 1 year following operation. There was no significant difference among these three groups. No suture materials were observed in the polydioxanone suture groups after 6 months following operation. This study suggests that polydioxanone suture will be useful for the repair of cardiovascular anomalies where growth of the suture line is required.

Absorption↗
PubMed1991

[Left atrial myxoma in a 16-year-old girl following acute myocardial infarction--a case report and a review of 17 cases in the world].

A 16-year-old girl had clinical signs of an acute myocardial infarction. Echocardiography revealed left atrial myxoma and coronary angiography demonstrated a complete obstructive lesion at LAD. Coronary arterial embolization from myxoma was strongly suggested. The tumor was removed successfully 32 days after acute coronary embolization. Coronary embolization from left atrial myxoma is extremely rare. There are only 17 reports in the world and we reviewed these reports.

Adolescent↗
PubMed1991

[Mitral and aortic valve replacement with tricuspid annuloplasty in a patient suffering from hereditary spherocytosis].

A 51-year-old woman was admitted with increasing shortness of breath. Preoperative evaluation disclosed MSr + ASr + TR. She had been undergone a splenectomy at 35-year-old for hereditary spherocytosis (HS). The patient underwent successful mitral valve replacement with a No. 25 Björk-Shiley (BS) valve, aortic valve replacement with a No. 21 BS valve, and tricuspid valve annuloplasty by means of membrane oxygenator (COBE). Haptoglobin and poloxamer 188 were used for prevention of hemolysis during extracorporeal circulation. No significant hemolysis occurred intra-or postoperatively. A very rare case of open heart surgery associated with HS was reported.

Aortic Valve↗
PubMed1991

[Methods of anesthesia in canine heart-lung transplants].

Hypothermia has many valuable merits compared with under cardiopulmonary bypass using pump oxygenator, as known. But, on the contrary, it has some weak points, such as, long time required for cooling and rewarming. We have developed the device for rapid cooling and rewarming by using jet water blows. It appeared that the key point in hypothermia was control of ether inhalation and timing of rewarming. We demonstrated that mongrel dog could survive for at least 72 hours after transplantation of heart-lung under simple deep hypothermia with ether anesthesia. The dog was breathing 50-100 percent oxygen gas under control through respiratory ventilator. Postoperative arterial blood gases were maintained between pH 7.3-7.5 and PO2 80-200mmHg on the other hand, PCO2 was unstable from 14 to 63mmHg. It seemed that the anesthesia in canine heart-lung transplants using profound surface hypothermia with either anesthesia was useful methods.

Anesthesia, Closed-Circuit↗
PubMed1990

Human T-cell leukemia virus type-I-infected T-cell lines scarcely produce p56lck, whether or not they express lck mRNA.

We have previously reported that lck mRNA (a lymphocyte-specific protein tyrosine kinase gene) is absent in human T-cell leukemia virus type I (HTLV-I)-infected interleukin-2(IL-2)-independent T-cell lines, while HTLV-I-negative T-cell lines and HTLV-I-positive IL-2-dependent ones express a large amount of lck mRNA. To further investigate the levels of lck expression, we prepared rabbit anti-Lck antiserum directed against the synthetic oligopeptide of 32 amino acids corresponding to the carboxy terminus of this gene product, p56lck. Using this antiserum, we show that HTLV-I-positive T-cell lines, whether they are IL-2-dependent or not, scarcely express p56lck. In other words, IL-2-dependent HTLV-I-positive T-cell lines seldom produce p56lck in spite of high expression of lck mRNA. Absence of p56lck is suspected of playing an important role in malignant transformation of HTLV-I-infected T-cells.

Blotting, Northern↗
PubMed1990

Decreased coronary vasodilatory capacity in hypertrophic cardiomyopathy determined by split-dose thallium-dipyridamole myocardial scintigraphy.

Split-dose thallium-dipyridamole myocardial scintigraphy was performed in patients with nonobstructive hypertrophic cardiomyopathy (HC) who had angiographically normal coronary arteries. The dipyridamole-induced increases in thallium-201 uptake, calculated to evaluate coronary vasodilatory capacity, were significantly lower in 30 patients with HC than in 13 control subjects (177 +/- 58 vs 281 +/- 46%) and the reductions were observed in both the septal and lateral segments. The reductions of the septal segment in HC patients were significantly greater than those in 10 hypertensive patients with comparable degrees of septal hypertrophy. Of patients with HC, 16 had increases in thallium uptake well below the normal range. Compared with those having normal increases, these patients had significantly lower exercise duration (11 vs 15 minutes), with 33% having ST depression develop at a workload less than or equal to 80 watts. These data indicate that approximately one-half of patients with HC have impaired coronary vasodilatory capacity that could be an important pathophysiologic abnormality of HC resulting in the development of myocardial ischemia and the impairment of cardiac performance during exercise.

Adolescent↗
PubMed1990

Recombination via flanking direct repeats is a major cause of large-scale deletions of human mitochondrial DNA.

Large-scale deletions of mitochondrial DNA (mtDNA) have been described in patients with progressive external ophthalmoplegia (PEO) and ragged red fibers. We have determined the exact deletion breakpoint in 28 cases with PEO, including 12 patients already shown to harbor an identical deletion; the other patients had 16 different deletions. The deletions fell into two classes. In Class I (9 deletions; 71% of the patients), the deletion was flanked by perfect direct repeats, located (in normal mtDNA) at the edges of the deletion. In Class II (8 deletions; 29% of patients), the deletions were not flanked by any obviously unique repeat element, or they were flanked by repeat elements which were located imprecisely relative to the breakpoints. Computer analysis showed a correlation between the location of the deletion breakpoints and sequences in human mtDNA similar to the target sequence for Drosophila topoisomerase II. It is not known how these deletions originate, but both slipped mispairing and legitimate recombination could be mechanisms playing a major role in the generation of the large mtDNA deletions found in PEO.

Base Sequence↗