Biomedical subjects

Y Kohno

Publications and source records attributed to Y Kohno.

At least 199 records · Page 11Linked to original sources

PubMed1993

[Analysis of ovalbumin-specific T cell lines established from patients with hen egg allergy].

Ten ovalbumin (OVA)-specific T cell lines (TCLs) were established from peripheral blood mononuclear cells of 6 patients with hen egg allergy, and the antigen recognition of these TCLs was characterized. Two OVA epitopes were determined by use of 3 synthetic OVA peptides which have been known as murine T cell epitopes. Blocking of antigen-specific T cell proliferation by anti-HLA class II monoclonal antibodies suggest that all 3 HLA class II molecules could act as restriction elements for T cell recognition of OVA. This is the first demonstration of OVA epitopes recognized by T cells in patients with hen egg allergy, as far as we know.

Cell Line↗

PubMed1993

[Assessment of myocardial perfusion abnormalities in patients with apical hypertrophic cardiomyopathy using exercise 201Tl scintigraphy].

Regional myocardial perfusion abnormalities commonly occur during exercise in patients with hypertrophic cardiomyopathy (HCM). Exercise 201Tl myocardial scintigraphy has provided a noninvasive means of identifying myocardial perfusion abnormalities in patients with HCM. On the other hand, apical hypertrophic cardiomyopathy (APH) is reported as a subtype of HCM. Whether APH is essentially equal to HCM or not is controversial. To assess myocardial ischemia in patients with APH, we studied 28 patients with APH, with exercise 201Tl SPECT. Myocardial perfusion images were obtained immediately after submaximal exercise and again after a 3-hour delay. Regional perfusion defects during exercise were identified in 19 of the 28 patients (68%) with APH. Complete reversible defects were observed in 15 (79%) patients with APH. Although perfusion defects were present in all regions of the left ventricle in patients with HCM, they were present only in the apical region in patients with APH. Thus, reversible 201Tl perfusion abnormalities commonly occur during exercise in patients with APH as well as in patients with HCM.

Adult↗

PubMed1993

Characterization of a thyroiditis-inducing thyroglobulin-specific T-cell clone restricted by the H-2 molecule of a low responder mouse strain.

We established a thyroglobulin (Tg)-specific, thyroiditis-inducing T-cell clone, B12G, from B6C3F1 mice by the immunization of mouse Tg with lipopolysaccharide (LPS) from Klebsiella strain LEN (O3:K1). B12G was Thy-1.2+, CD3+, CD4+, CD18+, and CD8-, and could transfer thyroiditis to recipient mice after in vitro stimulation with mouse or bovine Tg. Histological examination showed severe thyroiditis with predominant infiltrations of polymorphonuclear cells; few mononuclear cells were observed. B12G proliferated in response to bovine, mouse, porcine, and rat Tg in the presence of irradiated spleen cells, but did not respond to chicken or human Tg. H-2b, a low-responder haplotype of experimental autoimmune thyroiditis, governed the response of the clone to Tg. B12G produced interleukin-4 (IL-4) and IL-6, but not IL-2 or interferon-gamma (IFN-gamma), on stimulation with mouse Tg. These findings were different from characteristics of previously reported Tg-specific T-cell clones from high-responder mice in terms of epitope specificity and cytokine production pattern, raising the possibility that the specificities and functions of T cells involved in the development of autoimmune thyroiditis in low-responder mice differ from those in high responders.

Animals↗

PubMed1993

[A case of rigid spine syndrome--histological findings of muscles].

A 10-year-old boy with rigid spine syndrome was reported. He had mild weakness in the limb, and moderate weakness in the neck flexor and extensor muscles since early childhood. Because of limited flexion of the spine, he could not bend down. CT of the muscles revealed increased low density in the erector spine muscle, predominantly at the lumbar level. In the biopsy specimens obtained from the left biceps brachii and erector spine muscles, there was a variation in fiber size with scattered necrotic and regenerating fibers, and fibrosis, predominantly in the latter. Except for scattered fibers with rimmed vacuoles, the overall histopathological features were similar to those seen in progressive muscular dystrophies, suggesting that the dystrophic process is one of the major pathomechanisms for rigid spine syndrome.

Child↗

PubMed1993

[Assessment of reverse redistribution on exercise 201Tl myocardial SPECT in patients with hypertrophic cardiomyopathy].

Reverse redistribution is revealed on exercise 201Tl myocardial SPECT in some cases with hypertrophic cardiomyopathy. Ten patients with hypertrophic cardiomyopathy without coronary artery disease who showed reverse redistribution visually were studied. Reverse redistribution was evaluated by the early and delayed images of exercise 201Tl myocardial SPECT. Relation between reverse redistribution and distribution of left ventricular hypertrophy estimated by echocardiography and magnetic resonance imaging was investigated, and the mechanism of reverse redistribution was analyzed by referring to Bull's eye display of washout rate. Reverse redistribution was displayed in non-hypertrophic region and washout rate was normal in that region and low in hypertrophic region. In conclusion, in order to interpret reverse redistribution it is necessary to recognize hypertrophic region and to refer to washout rate.

Adult↗

PubMed1993

[The relation between the anaerobic threshold and exercise-induced myocardial ischemia in patients with ischemic heart disease].

The aim of this study was to clarify whether the anaerobic threshold (AT) in patients with ischemic heart disease is determined by exercise-induced myocardial ischemia. A) The reproducibility of the VO2 at the AT (AT VO2) were studied. In 13 patients with exercise-induced myocardial ischemia, submaximal Treadmill exercise tests were performed twice using a cardiopulmonary monitoring system. The reproducibility of the AT VO2 was good (r = 0.92), and the mean +/- SD was -1.3 +/- 8.2%. B) The change of the AT VO2 after percutaneous transluminal coronary angioplasty (PTCA) was studied. In 30 patients who underwent successful PTCA, submaximal Treadmill exercise tests were performed before and after PTCA using a cardiopulmonary monitoring system. After PTCA both the exercise duration and the peak VO2 increased significantly (569.0 +/- 200.8 sec vs 681.9 +/- 206.9 sec, p < 0.001: 19.5 +/- 3. 4ml/min/kg vs 21.3 +/- 3.7ml/min/kg, p < 0.001). On the other hand, the AT VO2 did not increase (13.7 +/- 3.0 ml/min/kg vs 13.9 +/- 3.2ml/min/kg, NS). The significant increase of the AT VO2, more than 15.1%, was recognized only in 5 patients. Neither did the AT VO2 increase even in patients without hibernating myocardium. In conclusion, there are many cases in which AT is not determined by exercise-induced myocardial ischemia.

Aged↗

PubMed1993

[Transthoracic Doppler color imaging of the blood flows in the left coronary septal branches].

This study characterized blood flow signals derived from the left coronary septal branches by transthoracic Doppler color flow imaging. In the anterior ventricular septum, the signal was detected in 7 of 13 patients with aortic stenosis, 8 of 34 with hypertrophic cardiomyopathy, and 5 of 144 patients with other diseased states. The peak diastolic flow velocity assessed by a pulsed Doppler technique ranged 21-115 cm/s (mean 57). Systolic signal was depicted in 13 of the 20 with the diastolic signal, indicating retrograde flow direction in all of them. The peak negative systolic component ranged 11-80 cm/s (mean 40). Peak diastolic flow velocity of the left anterior descending artery was higher in patients with the septal branch flow signal than in those without the signal (53 +/- 24 vs 31 +/- 11 cm/s). Patients with the signal showed larger transvalvular pressure gradient in aortic stenosis, and greater septal thickness in hypertrophic cardiomyopathy than in those without the signal. In conclusion, transthoracic visualization of the septal branch flow signal by Doppler color flow mapping is attributable to increased coronary blood flow at rest which is probably due to excessive load and/or septal hypertrophy. Augmented systolic retrograde flow may play additional role in the diastolic high velocity flow in the septal perforator.

Adolescent↗

PubMed1993

[A case of stunned myocardium: dual SPECT findings similar to acute myocardial infarction (AMI)].

Emergent cardiac catheterization was performed on a 70-year-old female patient who was admitted for further evaluation of acute myocardial infarction. Coronary angiography didn't reveal any significant stenotic lesion, but levogram showed extensively abnormal contractility around the center of the apex region. On the second hospital day, 99mTc-PYP/201TlCl dual SPECT gave findings similar to those found in acute myocardial infarction, but myocardium--released enzyme stayed within the normal range. Two weeks after, 201TlCl myocardial scintigraphy showed disappearance of the perfusion defect, and normal contractility was observed on the levogram of the chronic phase. Since this case was clinically denied to be myocardial infarction, it was considered a typical case of stunned myocardium which showed prolonged left ventricular abnormal contractility with transient myocardial ischemia. This is a case suggestive for estimations of myocardial reversibility in patients with myocardial perfusion and metabolic disorder in dual SPECT.

Aged↗

PubMed1993

[Effect of verapamil on myocardial ischemia in patients with hypertrophic cardiomyopathy: evaluation by exercise 201Tl SPECT].

Effect of verapamil on myocardial ischemia in patients with hypertrophic cardiomyopathy (HCM) was evaluated by exercise stress myocardial 201Tl SPECT (EX-Tl). EX-Tl were performed before and after 8.8 weeks of oral verapamil (240 mg/day) in 12 patients with HCM who showed transient 201Tl perfusion defects under control conditions. 201Tl perfusion defect was visually scored and judged for 4 grades as normal (0), mild defect (1), moderate defect (2), and severe defect (3). Transient Dilation Index (TDI) was calculated as an index of subendocardial ischemia. Improvements of defect score were demonstrated in 10 patients after administration of verapamil. Two patients showed no change of defect score. Mean defect score decreased significantly from 5.50 to 3.03 (p < 0.001). Although 11 of 12 patients showed abnormal TDI under control conditions, 10 of them revealed improvements of TDI and 7 of those 10 patients disclosed normal TDI after verapamil. Mean TDI decreased from 1.263 to 1.090 significantly (p < 0.01). In conclusion, verapamil may improve myocardial ischemia in patients with HCM.

Adult↗

PubMed1993

Predominant expression of nPKC eta, a Ca(2+)-independent isoform of protein kinase C in epithelial tissues, in association with epithelial differentiation.

Of the nine known members of the protein kinase C (PKC) family, we found that novel (n-) PKC eta, a newly isolated Ca(2+)-independent isoform, was expressed at the highest level in the epidermis of mouse skin and epithelia of the digestive and respiratory tracts including the tongue, esophagus, forestomach, glandular stomach, intestine, colon, trachea, and bronchus. Expression of nPKC eta mRNA in these epithelial tissues was 3-10 times that in the brain and was especially high in squamous epithelium. Two other PKC isoforms, conventional (c-) PKC alpha and nPKC delta, were also expressed in these epithelial tissues, but no cPKC gamma was detected. In situ hybridization and immunohistochemical analyses demonstrated the localization of nPKC eta in suprabasal layers of the skin, tongue, esophagus, and forestomach. In the intestine, it was expressed in the epithelial cells of villi, but not of crypts. In the lung, only bronchial epithelium expressed nPKC eta. The localization of nPKC eta in differentiating or differentiated epithelial cells, rather than in proliferating basal cells, suggests the involvement of nPKC eta in epithelial differentiation.

Amino Acid Sequence↗

PubMed1992

[Hepatic arteriography under temporary hepatic venous occlusion].

Hepatic arteriography with and without temporary segmental hepatic vein occlusion was performed in 10 patients, five of whom had chronic liver injury. Hepatic arteriograms obtained during hepatic venous obstruction demonstrated significantly more peripheral and definite arterial branches in the occluded area and fewer peripheral branches in the non-occluded segment. A prolonged, dense hepatogram (sinusoidogram) showing hepatofugal opacification of the portal vein was obtained in the occluded area. Only one case with a large veno-venous anastomosis did not show these findings. Hepatic arteriograms in two cases with hepatocellular carcinoma provided clear visualization of peripheral portal branches that could act as efferent tumor vessels during regional temporary hepatic vein occlusion. Temporary hepatic venous occlusion may cause a sudden increase of hepatic arterial flow in the occluded area and transsinusoidal arterioportal communication there. This method can be useful for the diagnosis and arterial infusion or embolization therapy of hepatic diseases.

Adult↗

PubMed1992

[Quantitative evaluation of liver function using 99mTc-GSA in rats with liver injury induced by ischemia-reperfusion].

We evaluated quantitatively the liver injury of rats induced by ischemia-reperfusion, using 99mTc-DTPA-Galactosyl-Human-Serum-Albumin (99mTc-GSA). The vessels of the left lobe were clamped for 5, 10, or 45 minutes followed by 15 minutes reperfusion. Then, 99mTc-GSA was intravenously administered (170 micrograms/kg body weight) to rats. Two compartment analysis was made on measurement curves in the heart and liver to obtain clearance parameters. Significant difference was observed between the ischemic group (clamped for 10 and for 45 minutes) and the control. These results suggest that 99mTc-GSA is useful in the estimation of liver injury produced by ischemia-reperfusion.

Animals↗

PubMed1992

A new model of equilibrium dysfunction in the rat induced by photochemical damage to the inner ear's microcirculation.

A new photochemical method was employed to damage the inner ear microcirculation in the rat. Under pentobarbital anesthesia, the middle ear was exposed by a ventral approach and the tympanic membrane and the malleus and incus were removed. The vestibule was then illuminated by a filtered xenon light (wave length: 540 nm) while rose bengal was infused intravenously. Microscopic examination revealed disintegration of the hair cells in the vestibule. Changes could be prevented by pretreatment with intravenous acetylsalicylic acid (ASA) or heparin. Twenty-four hours after the completion of photo-illumination the rats exhibited nystagmus toward the intact ear and showed rolling during the swimming test, both signs of equilibrium dysfunction. These findings were inhibited by ASA or heparin pretreatment. Our present results indicate that our method causes a photochemically induced occlusion in the rat's inner ear microcirculation and may be useful for evaluating the various effects of drugs on the inner ear.

Animals↗

PubMed1992

Detection of house dust mite (HDM)-specific IgE antibodies on nasal mast cells from asthmatic patients whose skin prick test and RAST are negative for HDM.

Mast cells are found in nasal smears of pediatric patients with perennial bronchial asthma whose skin prick test and radioallergosorbent test (RAST) are negative for inhalant allergens. IgE antibodies were demonstrated on these mast cells by monoclonal anti-human IgE antibodies, whereas IgG antibodies were not detected by monoclonal anti-IgG antibodies. In order to pursue the causative allergen for asthma in these patients, binding potential between IgE antibodies on nasal mast cells and house dust mite (HDM), the most prevalent aeroallergen, was examined by an immunochemical technique. Out of 9 patients whose skin prick test and RAST were negative for HDM, 7 were found to have HDM-specific IgE antibodies on their nasal smear mast cells. None of these 7 patients had IgE antibodies to cedar pollen, a negative control aero-allergen, on their mast cells. Specific binding of HDM on the mast cells was further confirmed by the fact that nasal mast cells from patients with egg allergy bound egg white but not HDM on their surface. Preincubation of mast cells with anti-IgE antibodies inhibited binding of HDM on the mast cells, indicating that HDM was bound to surface IgE antibodies on the mast cells. These experiments enabled us to expeditiously identify sensitization to an inhalant allergen, such as HDM, in young asthmatic patients whose allergen cannot be found by conventional laboratory diagnostic procedures.

Allergens↗

PubMed1992

[Research and development of clarithromycin].

A series of O-alkylated derivatives of erythromycin (EM) has been prepared and their biological properties were evaluated. Among them, clarithromycin (CAM, 6-O-methylerythromycin) exhibits most potent in vitro and in vivo antibacterial activities, higher acid-stability than EM and favorable pharmacokinetic properties as an antibiotic. CAM was originally synthesized via methylation of 2'-O,3'-N-bis(benzyl-oxycarbonyl)-N-demethylerythromycin in low yield, because of the less selectivity of 6-O-methylation. The selective 6-O-methylation was achieved using the erythromycin 9-oxime derivative as a key intermediate. By the further investigation on the protective groups of 9-oxime and desosamine moiety, the production process of CAM on an industrial scale has been established via methylation of 2',4''-O-bis(trimethylsilyl)erythromycin 9-[O-(1-isopropoxycyclohexyl)oxime] in more than 45% overall yield. CAM has the same antibacterial spectra as EM and is active against aerobic Gram-positive bacteria, some Gram-negative bacteria, anaerobic bacteria, Mycoplasma and Chlamydia. The activity of CAM against clinical isolates was 1 to 16 times higher than that of EM. The efficacies of CAM were 6 to 15 times superior to those of EM against systemic infections due to Gram-positive bacteria in mice. CAM also showed more potent therapeutic efficacies than EM against respiratory tract infections caused by S. pneumoniae and H. influenzae. CAM was well absorbed after oral administration, and its distribution to various tissues was significantly higher than that of EM in animals. The level of CAM in the lung was extremely high, which accounted 69 times that of EM. CAM was found to be distributed predominantly in the alveolar wall, especially in the alveolar epithelial cells, by microautoradiography. After oral administration in human, the serum level and urinary excretion of CAM were 5 and 20 times higher than those of EM, respectively. The major and active metabolite of CAM in human, (14R)-14-hydroxyclarithromycin, existed in significant quantity in the serum and urine, suggesting that the metabolite contributes to the excellent clinical efficacy of CAM. This paper describes the synthesis, structure-activity relationships, antibacterial activities, metabolism and clinical efficacies of CAM, a new macrolide antibiotic.

Animals↗

PubMed1992

Characteristics of the association of brotizolam, a thieno-triazolo diazepine derivative, with the benzodiazepine receptor: a selective and high affinity ligand of the central type I benzodiazepine receptor.

Characteristics of the association of brotizolam, a thieno-triazolo diazepine derivative, to central benzodiazepine receptors were examined. Brotizolam significantly displaced the [3H]flunitrazepam and [3H]beta-carboline carboxylate ethylester bindings to crude synaptic membrane from the rat brain. This agent had the highest affinity for benzodiazepine receptors in the cerebellum, and it was found to be 2.1 times that in the spinal cord. Furthermore, a low concentration of brotizolam potentiated the GABA-stimulated 36Cl- influx into membrane vesicles. In contrast, the bindings of [3H]8-hydroxy-2-(di-n-propylamino)tetralin to 5-hydroxytryptamine1A receptors and [3H]ketanserin to 5-hydroxytryptamine2 receptors were not affected by brotizolam. The present results suggest that brotizolam may be a selective and high affinity ligand for the type I central benzodiazepine receptor. The anxiolytic and hypnotic actions of brotizolam seem to be not due to the association with 5-hydroxytryptamine receptor, but due to the activation of the GABAA receptor complex. Furthermore, the present results suggest that the lower affinity of brotizolam to benzodiazepine receptors in the spinal cord than those in the cerebellum may be related to the low muscle relaxation action of this drug.

Animals↗

PubMed1992

Percutaneous transluminal coronary angioplasty in a patient with Kawasaki disease. A case report of an unsuccessful angioplasty.

A 13-year-old boy with severe coronary stenosis due to Kawasaki disease underwent percutaneous transluminal coronary angioplasty (PTCA). The guide wire and the balloon catheter easily passed through the stenosis in the left anterior descending artery. However, effective dilatation could not be achieved even when the balloon size was increased to 2.5 mm in diameter. We discontinued further inflation of the balloon because serious resistance was encountered on withdrawal of the balloon catheter. In patients with Kawasaki disease, the value of PTCA as a treatment for coronary stenosis is questionable.

Adolescent↗

PubMed1992

The effect of percutaneous transluminal coronary angioplasty on anaerobic threshold in patients with angina pectoris.

The anaerobic threshold (AT) is regarded an objective parameter for evaluating exercise tolerance, but its relationship to the improvement of myocardial ischemia remains uncertain. To investigate this relationship, submaximal treadmill exercise tests were performed for 15 consecutive patients with angina pectoris who had undergone successful percutaneous transluminal coronary angioplasty (PTCA). Before and after PTCA, the AT was determined using cardiorespiratory monitoring, while the patients were receiving their usual vasodilator medications. 1) Before PTCA, the minute oxygen uptake (VO2) at the AT correlated well with the peak VO2 (r = 0.92, p < 0.002). The VO2 at the AT, however, showed less correlation (r = 0.71, p < 0.002) with the VO2 at ST segment depression, while the latter parameter correlated closely with the peak VO2 (r = 0.91, p < 0.002). 2) After PTCA, exercise time, peak VO2, and the double product at peak exercise increased significantly (from 640.1 +/- 212.2 to 772.9 +/- 230.0 sec, p < 0.001, from 19.1 +/- 5.2 to 22.4 +/- 4.9 ml/min/kg, p < 0.05, and from 19.7 +/- 5.0 x 10(3) to 23.7 +/- 4.5 x 10(3), p < 0.001, respectively). However, the VO2 at the AT did not increase significantly (from 15.8 +/- 4.1 to 16.6 +/- 3.5 ml/min/kg, p = NS). The heart rate, systolic blood pressure, and double product at the AT did not change significantly. In conclusion, in patients with angina pectoris, the AT is apparently related to the onset of myocardial ischemia. However, the AT does not necessarily reflect acute improvement of myocardial ischemia immediately after PTCA.

Aged↗