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Biomedical subjects

S Nagata

Publications and source records attributed to S Nagata.

At least 685 records · Page 38Linked to original sources
PubMed1984

Atopic disposition and bronchial reactivity to inhaled acetylcholine in young adults with a history of asthma in childhood.

The atopic disposition, indicated by positive skin reactions and IgE antibody titers etc., and the bronchial reactivity to inhaled acetylcholine were examined on the following three groups: (1) 20 young adults with a history of childhood asthma who have been symptom-free for more than 4 yr; (2) 20 current asthmatics, and (3) 20 healthy young adults. Young adults with a history of childhood asthma remained atopic in their disposition even after complete clinical remissions of their childhood asthma. However, they had a lower bronchial reactivity as compared with current asthmatics, although the bronchial reactivities of both groups were apparently higher than the control group.

Acetylcholine↗
PubMed1984

Induction of T cell differentiation in early-thymectomized Xenopus by grafting adult thymuses from either MHC-matched or from partially or totally MHC-mismatched donors.

The effect of grafting thymuses from major histocompatibility complex (MHC)-matched and mismatched (either partially or totally) adult donors on the restoration of T-cell dependent immune responses of Xenopus adults that were thymectomized (txd) during early larval life was examined. Four to 5 month-old diploid (or triploid) frogs of defined MHC haplotypes that had been txd on day 4 or 5 postfertilization were each grafted subcutaneously with a pair of thymuses from a triploid (or diploid) MHC-defined frog. Regardless of the donor-host combination, thymus grafts restored in vivo acute skin allograft rejection capacities and antibody responses to SRBC and in vitro proliferative responses of spleen cells to the T cell mitogens, PHA and Con A. Txd frogs that were grafted with MHC-mismatched thymus did not reject skin grafts with the MHC haplotype of the thymus donor. Nevertheless, their spleen cells could proliferate, in one way MLC, in response to irradiated stimulator cells with the thymus donor MHC haplotype. Ploidy analyses of mithramycin-stained thymic and splenic lymphocytes (DNA quantitation by flow cytometry) demonstrated that in certain donor-host combinations, cells from totally or partially MHC-mismatched donors as well as from MHC-matched donors persisted in the thymus grafts and/or the spleens of txd hosts. Chimerism lasted for at least 1 year after thymus grafting. In other donor-host combinations, however, (txd isogenic cloned LG15 frogs grafted with allogeneic thymus from MHC-homozygous triploid J strain frogs), no donor cells could be detected 7 months after thymus grafting. Chromosome counts of PHA-induced metaphases of spleen cells from these and other thymus-grafted frogs revealed host cells in metaphase. This suggests that thymus grafts can promote the differentiation of host precursor cells along a T cell pathway.

Animals↗
PubMed1984

[Left ventricular thrombus formation and cuspal fusion of the prosthetic valve during left heart bypass: their pathophysiological significance and echocardiographic observations].

The echocardiographic findings during left ventricular assist of a heart of a 36-year-old woman who underwent mitral valve replacement were described. Blood was bypassed from the left atrium to the aorta. Echocardiography demonstrated that the pulmonary and tricuspid valves functioned with each heart beat, but that the aortic and prosthetic mitral valves did not open, and the left ventricular wall did not contract. In the left ventricular cavity, there was a mobile and amorphous thrombus which correlated with dynamic intracavitary micro-echoes ("moya moya" echoes). With higher left atrial pressure, the left ventricular motion increased slightly, and the left ventricular dimension gradually decreased. These findings were interpreted as follows: (1) desired results were attained from the previous powerful assist, or (2) the most optimum pressure of the left atrium in relation to the left ventricle was relatively high. It has not yet been determined which is actually the case. The "moya moya" and thrombus echoes were decreased. The general condition of the heart appeared to be improved, but the prosthetic valve motion was not observed. Contrast study via an echocardiographically-guided catheter inserted retrogradely into the left ventricular cavity revealed prosthetic valve stenosis. Fusion of its cusps by fibrin was confirmed on repeat surgery. Although the patient's condition allowed removal of the left ventricular assist device after surgery, the patient died of progressive infection. Optimum powerful assist should be performed while the formation of thrombi and cuspal adhesions is being prevented by other methods, or a more mild assist may be desirable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Improved assay for alcohol dehydrogenase activity in serum by centrifugal analysis.

We describe an improved method for determination of alcohol dehydrogenase (EC 1.1.1.1) activity in 60 microL of human serum, based on conversion of ethanol to acetaldehyde with simultaneous reduction of NAD+ in glycine NaOH buffer (pH 9.0) at 37 degrees C in a centrifugal analyzer. The final concentration of NAD+ was 10 mmol/L and ethanol was 20 mmol/L. The dilution curve was linear with enzyme activity up to 200 U/L, and results by this method correlated well with those by a manual method (N Engl J Med 279: 241-248, 1968). Within-run precision (CV) was 0.9 to 8.2% over the range of 4.5 to 88.1 U/L, and day-to-day precision was 5.4 to 5.6%. In sera from 198 healthy individuals, mean alcohol dehydrogenase activity was 1.6 (SD 1.2, range 0-5) U/L. To evaluate the clinical utility of determining alcohol dehydrogenase, we measured the activity of alanine aminotransferase and alcohol dehydrogenase in sera from 470 patients with various diseases in our hospital, and found that results for the two enzymes did not correlate well.

Adult↗
PubMed1984

[Mitral valve lesions in patients with right ventricular pressure overload: analysis using realtime, two-dimensional echocardiography].

Mitral valve lesions in patients with right ventricular pressure overload, such as pulmonary stenosis, tetralogy of Fallot, and pulmonary hypertension, were studied by real-time, two-dimensional echocardiography, and the following results were obtained. The abnormality observed in the mitral valve was a systolic dislocation of the anterior and posterior mitral leaflets at the coaptation zone. Mitral valve lesions were noted in 16 of 46 cases, i.e. nine of 11 with pulmonary hypertension (82%), four of 20 with tetralogy of Fallot (20%), and three of 15 with pulmonary stenosis (20%). The incidence was highest in patients with pulmonary hypertension. In eight of 16 cases with mitral valve lesions, mitral regurgitation was observed by either left ventriculography or two-dimensional Doppler echocardiography. Mitral valve lesions were always located at the posteromedial commissure of the anterior mitral leaflet. Considering the previous similar reports in secundum atrial septal defect, we attributed the cause of the mitral valve lesions to the same mechanism. No clear relation could be found between the left ventricular deformity index and the incidence of mitral valve lesion. Therefore, we could not conclude about the mode of production of mitral valve lesions occurring in the diseases with right ventricular pressure overload.

Adolescent↗
PubMed1984

[Ventricular interdependence reflected in interventricular septal motion: with special reference to right ventricular pressure overload].

The dynamic features of the interventricular septum were studied with two-dimensional echocardiography with special reference to the influence of right ventricular (RV) pressure overload. The subjects were 52 patients, including 30 with atrial septal defect (ASD), 14 with rheumatic mitral valvular disease and 8 with pulmonary hypertension (PH) due to cor pulmonale, pulmonary embolism, or primary PH. To assess septal motion, the configuration of the left ventricle (LV) in the short-axis view was quantified as the deformity index, and characterized as the distortion from right circle. As an accurate short axis was required to assess the deformity of the cavity, the transducer was attached to the guide arm, providing comparable positions and directions. The deformity index was highest at the chordal level among other levels in the same cardiac phase. In ASD without PH, the deformity was minimal in end systole and maximal in early diastole. The index curve showed two peaks in early diastole and these times coincided with those of the minute backward notches on the ventricular septal echogram. In ASD with PH, the deformity was minimal in early systole and became greater during systole. The maximum deformity was shown in early diastole, corresponding to the momentary retracting motion of the septum by M-mode echocardiography. At that moment, the septum became convex to the LV. In patients with RV pressure overload, the systolic peak of the RV pressure was delayed and the decrease in pressure became sluggish, resulting in the RV pressure exceeding that of the LV transiently in early diastole. This was the reason for the septum becoming convex to the LV in this phase. Among the patients, the bi-ventricular systolic pressure ratio correlated not only with the index in end systole but also with that in early diastole. Good correlation between systolic pressure ratio and early diastolic deformity index seemed to be attributable to the fact that the higher the RV systolic pressure, the larger the reversed pressure gradient between both ventricles in early diastole.(ABSTRACT TRUNCATED AT 400 WORDS)

Diastole↗
PubMed1983

Different binding of human interferon alpha 1 and alpha 2 to common receptors on human and bovine cells. Studies with recombination interferons produced in Escherichia coli.

Minicells from Escherichia coli DS410 harboring cDNA for human interferon (IFN) alpha 1 or alpha 2 were metabolically labeled with [3H]leucine and the radioactive IFN was purified to homogeneity by immune precipitation with anti-IFN-alpha serum. These preparations of radioactive IFN-alpha 1 and -alpha 2 were used to study the binding on two human (FL and Daudi) and one bovine (MDBK) cell lines. IFN-alpha 2 specifically bound well to both human and bovine cells, while IFN-alpha 1 bound very poorly to human cells but well to bovine cells. Specific binding of radioactive IFN-alpha 2 to these cell lines was completely inhibited by not only nonradioactive IFN-alpha 2 but also IFN-alpha 1, and binding of IFN-alpha 1 to bovine cell was also competed by IFN-alpha 2 as well as IFN-alpha 1, indicating that the receptors for both IFNs are identical. However, 50-100-fold (on human cells) or 4-fold (on bovine cell) more nonradioactive IFN-alpha 1 than -alpha 2 was required to inhibit the binding of radioactive IFN-alpha 2 to the receptors. Scatchard analysis showed that IFN-alpha 1 and -alpha 2 bind to the receptors on human cells with an apparent Kd of greater than 6 X 10(-10) and 3 X 10(-11) M, respectively, while on bovine cells with a Kd of 4.2 X 10(-11) and 1.6 X 10(-11) M, respectively. These results show that the different target cell specificity of IFN-alpha 1 and -alpha 2 in regard to antiviral activity (Streuli, M., Hall, A., Boll, W., Stewart, W. E., II, Nagata, S., and Weissmann, C. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 2848-2852) is due to the different binding activity of IFN-alpha molecules to their common receptors.

Animals↗
PubMed1983

Specific in vivo and nonspecific in vitro alloreactivities of adult frogs (Xenopus laevis) that were thymectomized during early larval life.

Thymectomy of very young Xenopus larvae abrogated in vitro proliferative responses to phytohemagglutinin (PHA) and allogeneic leukocytes. Thymectomized (Txd) frogs, however, still rejected first-set skin allografts chronically and second-set grafts (but not third-party grafts) more rapidly. The specific second-set rejection reaction by Txd frogs was transferable in vivo to secondary Txd hosts (with major histocompatibility complex identical to the cell donor) by the subcutaneous injection of a mixture of splenic and peripheral blood leukocytes. Spleen cells used in this adoptive transfer experiment (i.e., immune cells) were responsive to allogeneic cells from the original donor strain as well as from unrelated donors in mixed leukocyte culture in vitro but were still unreactive to PHA. The results are consistent with an extrathymic pathway of alloreactive cell differentiation in this species, although the physiological significance of such a pathway is not clear.

Animals↗
PubMed1983

Minimization of inflammation in the treatment of bladder tumors by intravesical instillation of adriamycin.

The purpose of this trial was to minimize local inflammation caused by intravesical instillation of antitumor agents, especially Adriamycin, in the treatment of bladder tumor. Tranexamic acid was chosen as the solvent vehicle for Adriamycin and IV bolus injection of an antiallergic drug, Stronger neo-minophagen C, was given at the time of each instillation. Of 81 cases scheduled for Adriamycin instillation therapy, nine cases (11.1%) dropped out due to severe bladder inflammation, while 17 other cases (21%) experienced local side-effects which were tolerated. Of 62 evaluable cases in whom more than eight instillations were performed, complete regression was observed in six cases (9.7%) and partial regression in 20 cases (32.3%).

Animals↗
PubMed1983

Potentiation of halothane hepatotoxicity by chronic ethanol administration in rat: an animal model of halothane hepatitis.

To determine if chronic ethanol administration modifies the effect of halothane on the liver, fourteen male Wistar rats were pair-fed nutritionally adequate liquid diets containing either ethanol (36% of calories) or isocaloric carbohydrate (controls) for 6 weeks. After halothane anesthesia of these animals under different oxygen concentration, the livers were examined light microscopically as well as biochemically. The livers from rats fed ethanol which received halothane at low oxygen concentration showed multifocal or patchy necrosis primarily in the centrilobular regions with parenchymal lipid accumulation, whereas no such lesions were not observed in pair-fed controls. Hepatic necrosis was also seen after halothane anesthesia even at ambient oxygen concentrations, although the degree of necrosis was much milder. Hepatic microsomal cytochrome P450 content was increased by 30% after ethanol but was decreased following halothane anesthesia. These data suggest that halothane is hepatotoxic to liver of rats chronically pretreated with ethanol, especially under hypoxic condition.

Alcoholism↗
PubMed1983

Molecular cloning and sequence determination of the nuclear gene coding for mitochondrial elongation factor Tu of Saccharomyces cerevisiae.

A 3.1-kilobase Bgl II fragment of Saccharomyces cerevisiae carrying the nuclear gene encoding the mitochondrial polypeptide chain elongation factor (EF) Tu has been cloned on pBR327 to yield a chimeric plasmid pYYB. The identification of the gene designated as tufM was based on the cross-hybridization with the Escherichia coli tufB gene, under low stringency conditions. The complete nucleotide sequence of the yeast tufM gene was established together with its 5'- and 3'-flanking regions. The sequence contained 1,311 nucleotides coding for a protein of 437 amino acids with a calculated Mr of 47,980. The nucleotide sequence and the deduced amino acid sequence of tufM were 60% and 66% homologous, respectively, to the corresponding sequences of E. coli tufA, when aligned to obtain the maximal homology. Plasmid YRpYB was then constructed by cloning the 2.5-kilobase EcoRI fragment of pYYB carrying tufM into a yeast cloning vector YRp-7. A mRNA hybridizable with tufM was isolated from the total mRNA of S. cerevisiae D13-1A transformed with YRpYB and translated in the reticulocyte lysate. The mRNA could direct the synthesis of a protein with Mr 48,000, which was immunoprecipitated with an anti-E. coli EF-Tu antibody but not with an antibody against yeast cytoplasmic EF-1 alpha. The results indicate that the tufM gene is a nuclear gene coding for the yeast mitochondrial EF-Tu.

Base Sequence↗
PubMed1983

Mitral valve lesion associated with secundum atrial septal defect. Analysis by real time two dimensional echocardiography.

Mitral valve lesions accompanying secundum atrial septal defect were examined in 120 successive patients from May 1978 to December 1980 using real time two dimensional echocardiography. The conclusions were as follows: (1) The characteristic feature of the mitral lesion accompanying secundum atrial septal defect is a dislocation of the mitral leaflet toward the left atrial side in the area of coaptation. (2) The mitral lesion is seen in about half the patients with secundum atrial septal defect. (3) It is usually seen only in the anterior leaflet, and is found near the posteromedial commissure. Lesions in other sites on the leaflet all accompany those near the posteromedial commissure. (4) The incidence, extent, and degree of the mitral valve lesion increase with age. (5) It is assumed that the mitral valve lesion in secundum atrial septal defect starts near the posteromedial commissure in the anterior leaflet, gradually deteriorates, and extends toward the anterolateral commissure. (6) It is probable that the mitral lesion results in mitral regurgitation. (7) The mitral valve lesion is similar in appearance to mitral valve prolapse caused by the floppy mitral valve, though their causative factors may be different. It is probably the reason why the mitral valve abnormality has been described as mitral valve prolapse in previous reports. In the present study the mitral lesion was evaluated on the distance of the dislocation between both leaflets at the area of coaptation. These criteria proved useful. Because of the similarity in appearance, it may be helpful in the assessment of primary mitral valve prolapse.

Adolescent↗
PubMed1983

Mechanism of systolic anterior motion of mitral valve and site of intraventricular pressure gradient in hypertrophic obstructive cardiomyopathy.

The mechanism of systolic anterior motion of the mitral valve and the localisation of the intraventricular pressure gradient were determined in 15 cases of hypertrophic obstructive cardiomyopathy by the combined use of real time two dimensional echocardiography and intracardiac manometry. We arrived at the following conclusions. The systolic anterior motion of the mitral echo in the M-mode echocardiogram can be classified into two types, I and II, based on two dimensional echocardiographic findings. In type I, the echo sources of systolic anterior motion are the anteriorly shifted mitral chordae and, in part, the papillary muscles. The intraventricular pressure gradient occurs at the level of the tip of the papillary muscle. The suprapapillary part of the outflow tract and the inflow part show a low pressure, while the apical cavity shows a high pressure. In type II, the echo sources of systolic anterior motion are the anterior and posterior mitral leaflets which are oriented in such a way as to obstruct the outflow tract. The pressure gradient occurs at the level of the anterior and posterior mitral leaflets. The inflow tract and the outflow tract just below the mitral leaflets show a high pressure, in contrast to type I systolic anterior motion. The inappropriate and maloriented papillary muscles play an essential role in causing both types of systolic anterior motion and outflow obstruction. The direction of the axis of the papillary muscle is changed in late systole, moving its tip away from the interventricular septum, resulting in a simultaneous reduction in systolic anterior motion.

Adult↗