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Biomedical subjects

M Ohta

Publications and source records attributed to M Ohta.

At least 1,207 records · Page 67Linked to original sources
PubMed1983

[Measurement of four chambers' volumes and ventricular masses by cardiac CT examination].

Using cardiac computed tomography (CT), the "mean" volume of each cardiac chamber and both ventricular masses were calculated from summation of a sliced volume by ungated scans obtained using rapid sequential scanning covering the whole heart. Estimation of a normal value of each chamber's volume was attempted in 20 patients with ischemic heart disease and with normal heart function. The "mean" volume of the right atrium (RAMV), right ventricle (RVMV), and left atrium (LAMV) was 22.3 +/- 6.5, 40.3 +/- 6.5 and 28.7 +/- 8.2 ml/m2, respectively. In 54 patients with valvular heart diseases, each chamber's volume obtained by CT was compared with the grade of tricuspid regurgitation (TR) estimated by ultrasonic Doppler technique or the grade of mitral regurgitation (MR) by left ventriculography (LVG). The RAMV (234 +/- 119 ml/m2) and the RVMV (101 +/- 39 ml/m2) were markedly increased in patients with severe TR (grade 3 to 4) (p less than 0.01). The LAMV (487 +/- 231 ml/m2) was also increased in patients with severe mitral regurgitation (grade 3 to 4) (p less than 0.01). In 46 patients with valvular heart diseases, the LVMV by CT was well correlated with end-diastolic volume (EDV) obtained by LVG (r = 0.92), and the LVEDVs by ECG gated CT and by LVG showed a fairly good correlation (r = 0.95). CT examination was performed before and after surgery in 17 patients with MR or TR for evaluation of the change of chamber volumes. The mean reduction ratio (MRR) of the RAMV after tricuspid annuloplasty, the LVMV after mitral valve plasty, and the LAMV after left atrial plication was 44%, 41%, and 60%, respectively.

Cardiac Volume↗
PubMed1983

[Clinical studies on cefadroxil in the field of pediatrics].

The newly developed cefadroxil (CDX) dry syrup in a mean daily dose of 32.9 mg/kg t.i.d. or q.i.d. was administered to children for a period of 8 days on the average; viz. a total of 64 cases consisting of 39 cases of tonsillitis, 2 of tonsillitis complicated with otitis media, 1 of bronchitis, 1 of pneumonia, 14 of scarlet fever, and 7 of urinary tract infections; and its clinical and bacteriological effects, and adverse reactions were examined, leading to the following results. 1. The clinical effects were "good" or "excellent" in any of 39 cases of tonsillitis, 2 of tonsillitis complicated with otitis media, 1 of pneumonia, 14 of scarlet fever, and 7 of urinary tract infections, and "fair" only in a case of bronchitis, showing the high efficacy of 98.4%. 2. The clinical effects by daily dose were compared only in the great cases of tonsillitis between the 2 daily dose groups of 30 mg/kg or below and 31 to 40 mg/kg, and both groups showed "good" or "excellent" results, but the latter group revealed that the excellent rate was greater by 20.8% than that of the former group. 3. The frequency of daily administration was 3 times or 4 times and the cases of 4 times administration were few in any disease. In comparison of clinical effects between the 3 times group and the 4 times group in the whole cases, no significant difference was observed between both groups but it is desirable to make the 4 times administration in view of the pharmacokinetics. 4. The bacteriological effects could be judged in 15 cases, namely bacteria were eradicated in 14 cases and unchanged in 1 case, showing a good result of the eradication rate as 93.3%. 5. No adverse reaction was observed and the laboratory test values showed eosinophilia in 7 cases (15.9%) and abnormal elevations of GPT in 1 case (4.5%), of GOT and GPT in 2 case (9.1%), of LDH in 1 case (4.8%) and of BUN in 1 case (4.8%), but 4 of the 7 cases with eosinophilia seemed attributable to underlying diseases or objective diseases. From the above it can be said that this preparation is a useful drug in mild bacterial diseases.

Adolescent↗
PubMed1982

Polyembryoma of ovary producing alpha-fetoprotein and HCG: immunoperoxidase and electron microscopic study.

Polyembryoma of ovary producing alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) was studied by indirect immunoperoxidase method for AFP and HCG, and electron microscopy. Clinically, this patient showed pseudoprecocious puberty caused by elevated HCG which is synthesized by trophoblastic cells in polyembryoma. She is put under VAC (vincristine, actinomycin-D, cyclophosphamide) chemotherapy after operation and shows no signs of recurrence including reelevation of serum AFP at five months after operation. Embryoid bodies which we studied correspond to normal embryo at 15- or 16-day stage. Immunoperoxidase study showed that AFP is synthesized by yolk sac cells of the embryoid bodies and HCG is synthesized by syncytiotrophoblastic cells. The finding about AFP synthesis suggests that normal embryo at 15- or 16-day stage may begin AFP synthesis. Electron microscopic study showed that each part of the embryoid bodies had some characteristic structures. Most striking features found in the cytodifferentiation of the embryoid bodies were noticed in some special differentiation of plasma membrane and existence of surface coat. Desmosomes were found in endodermal cells and yolk sac cells. Ectodermal cells were attached to each other by zonulae occludentes and adherentes. Microvilli were found in ectodermal cells and yolk sac cells. Two different kinds of surface coat were found in mesodermal cells and lining cells of yolk sac cavity: thin-layered deposit of electron-dense material covering the plasma membrane facing intercellular space of mesodermal cells and endodermal cells, and thick-layered deposit of electron-dense material which covered the plasma membrane facing yolk sac cavity of endodermal cells and yolk sac cells. Presence of similar characteristic material in RER of yolk sac cells led us to speculate that thick deposit was synthesized by yolk sac cells and secreted into yolk sac cavity. Combined with immunoperoxidase study by light microscopy, we assume that this thick-layered deposit has some close relation to AFP.

Child↗
PubMed1982

Amygdaloid-induced jaw opening and facilitation or inhibition of the trigeminal motoneurons in the rat.

1. Repetitive stimulation of the rat'se central amygdaloid (CAm) nucleus induced rhythmic masticatory jaw movements or continuous jaw opening. Both types of jaw movements were accompanied by coincidental activities of the mylohyoid (Myl) nerve. 2. The effects of CAm stimulation were examined on activities of bilateral Myl and masseteric (Mass) nerves or their motoneurons (Myl-Dig and Mass, respectively). 3. CAm stimulation induced contralaterally dominant facilitation of the Myl nerve activity as well as Myl-Dig motoneurons. These facilitatory effects were caused by EPSPs seen in Myl-Dig motoneurons. 4. One third of the Mass motoneurons were inhibited or hyperpolarized by contralateral CAm stimulation, while a few were facilitated and the majority unaffected.

Action Potentials↗
PubMed1982

Amygdaloid or cortical facilitation of antidromic activity of trigeminal motoneurons in the rat.

1. Electrical stimulation of the rat's contralateral central amygdaloid (CAm) nucleus or the contralateral frontal cortex markedly augmented the antidromic field potential evoked by stimulation of mylohyoid (Myl) nerve. 2. This facilitation was shown to be due to EPSPs of the mylohyoid-anterior digastric (Myl-Dig) motoneurons. 3. In a few motoneurons, cortical EPSPs had fixed short latencies following high-frequency double stimuli and this is believed to be due to a monosynaptic pathway. 4. The amygdaloid or cortically evoked EPSPs relieved IS-SD blockade in a few motoneurons and also facilitated antidromic discharge in others which did not show any IS or M spike response to the same subthreshold antidromic stimulation. The underlying mechanisms are discussed.

Amygdala↗
PubMed1982

Adjuvant action of bacterial lipopolysaccharide in induction of delayed-type hypersensitivity to protein antigens. II. Relationships of intensity of the action to that of other immunological activities.

Various kinds of lipopolysaccharides (LPS) isolated from different bacterial strains exhibited more or less an adjuvant action in induction of delayed-type footpad response to ovalbumin (OA) in mice when antigen was injected subcutaneously together with LPS. There was a wide diversity in strength of the adjuvant action of LPS, and the action of the 03 antigen isolated from the culture supernatant fluid of Klebsiella was the most potent of eleven kinds of LPS tested. Besides this substance, LPS extracted from Escherichia coli 08, 09 and 0128, and Salmonella typhosa exhibited relatively strong action. The difference in strength of the action of the high and low active LPS in induction of delayed-type hypersensitivity could be observed at any doses of OA and LPS. The strength of the adjuvant activity of LPS in induction of delayed-type hypersensitivity roughly correlated with that of their adjuvant activity in augmenting immunological memory for the secondary antibody response to OA and also their ability to enlarge the regional lymph node, whereas it did not apparently correlate with that of their activity to stimulate B cells polyclonally and their ability to enlarge the spleen.

Adjuvants, Immunologic↗
PubMed1982

Studies on the reaction mechanism of NADPH-adrenodoxin reductase with NADPH.

The existence of a multi-component equilibrium involving a reversible reaction was demonstrated in the anaerobic reaction of NADPH-adrenodoxin reductase or ferredoxin-NADPH reductase; EC 1.18.1.2 (AdR) with NADPH or in the photoreduction of AdR in the presence of NADP+ and EDTA. After anaerobic reduction of AdR with excess NADPH, not only the fully reduced state but also other states of the enzyme were demonstrated as a mixture of characteristic absorption spectra of a flavin semiquinone with a peak at 575 nm and a shoulder around 625 nm and a charge transfer complex between NADP+ and the fully reduced AdR with a broad absorbance in a longer wavelength region. The amount of oxidized form in the reaction mixture was only a trace judging from the absorbance at 450 nm. The oxidized form was observed in addition to the other spectral species when the concentration of NADPH was limited. The spectrum of the AdR reduced with excess NADPH changed reversibly between 2 degrees C and 29 degrees C with isosbestic points at 427 nm and 667 nm; the semiquinone form increased at the expense of the charge transfer complex at lower temperatures, and vice versa at higher temperatures. The anaerobic photoreduction of AdR in the presence of NADP+ and EDTA produced the same spectral species as seen in the NADPH-reduced AdR, and the spectrum of the photoreduced AdR also changed reversibly between 1 degree C and 33 degrees C in a similar way to that of the NADPH-reduced AdR; the oxidized form changed in parallel with the semiquinone form. It was also found that NADPH was produced continuously during the photoirradiation even after the spectral changes had ceased. The results show that anaerobic reduction of AdR with NADPH or the photoreduction of AdR in the presence of NADP+ and EDTA produces a multi-component equilibrium and the equilibrium is dependent upon the concentration of NADPH and the temperature. Attainment of the equilibrium involves not only the forward reaction of AdR with NADPH but also the reverse reaction of the fully reduced AdR with NADP+.

Anaerobiosis↗
PubMed1982

Further studies of the polysaccharide of Klebsiella pneumoniae possessing strong adjuvanticity. III. Augmentation of the antibody response to subcutaneously injected sheep red blood cells by the adjuvant polysaccharide.

The adjuvant action of the O3 antigen of Klebsiella (KO3) on the antibody response to sheep red blood cells (SRBC) was elucidated by injecting both KO3 and SRBC subcutaneously at the right inguinal region of SMA mice. We demonstrated that KO3 exhibits a novel ability to augment anti-SRBC plaque-forming cell responses in both the local lymph node and the spleen at a relatively late stage of immunization. Escherichia coli lipopolysaccharide, dextran sulfate and concanavalin A showed such an action only minimally. In parallel with the development of the adjuvant action, KO3 definitely activated B cells in the local lymph node polyclonally for either IgM or IgG synthesis, suggesting that the mechanism of the adjuvant action includes direct stimulation of B cells by KO3 at the late stage. Neither increase in trapping of lymphocytes in the local lymph node nor change in tissue distribution of antigen was shown to be primarily involved in the mechanism of the adjuvant action.

Adjuvants, Immunologic↗
PubMed1982

Cells constituting cerebellar hemangioblastomas. Ultrastructural study.

Five capillary hemangioblastomas exhibiting a range of histologic variations common to this tumor were studied using electron microscopy. The capillary hemangioblastoma were composed commonly of three cell lines -- stromal cells, endothelial cells and pericytes. In addition, extramedullary hematopoietic foci were seen in the tissue of one case. We regarded all these cellular elements as neoplastic components. The interconvertibility among them was not confirmed. The capillary hemangioblastomas were highly organized by those multiple cell lines. The histologic pattern of growth was arbitrarily subgrouped into stromal cell prominent type and capillary prominent type. Intermediate features between the two types were observed. These different types would depend on relative proportions and the degree of maturity of the constituting cell elements. From the histogenetic point of view, we considered capillary hemangioblastomas as being a hamartomatous tumor.

Adult↗
PubMed1982

Evaluation of tricuspid regurgitation by pulsed Doppler and two-dimensional echocardiography.

We analyzed tricuspid regurgitation noninvasively using ultrasonic pulsed Doppler and two-dimensional echocardiography in 66 patients in whom tricuspid regurgitation was suspected from routine clinical evaluation. All of the patients also underwent right ventriculography. Ten healthy subjects served as controls. In 62 of 66 patients, the study was adequately performed. In 58 of 62 patients, pansystolic abnormal Doppler signals were detected in the right atrial cavity, and were interpreted to indicate tricuspid regurgitant flow. Two-dimensional echocardiograms in the parasternal four-chamber view demonstrated that the region in which the abnormal Doppler signals were detected was spindle-shaped and extended from the tricuspid orifice toward the right atrial posterior wall parallel to the interatrial septum. The severity of regurgitation was graded on a four-point scale, based on the distance reached by the abnormal signals from the tricuspid orifice toward the posterior wall. For comparison, the right ventriculograms were evaluated on a four-point scale similar to the Sellers classification of mitral regurgitation. The grades by the two methods matched exactly in 36 cases, differed by one level in 23 and by two levels in three. Thus, the two methods showed a good correspondence. Similar results were obtained for the grading based on the area covered by the abnormal signals. We conclude that noninvasive grading of tricuspid regurgitation by ultrasonic pulsed Doppler and two-dimensional echocardiography is practicable.

Adult↗
PubMed1982

Difference in age-hardening mechanism in dental gold alloys.

TEM and SAED studies were conducted to clarify a difference in age-hardening mechanism with changes of gold content in Au-Cu-Ag ternary alloys, 18K, 16K, and 14K gold alloys, for which the ratio of copper to silver remained at 65 to 35 in weight. Age-hardening in the 18K alloy was attributed to the formation of the AuCu I type ordered platelets on the matrix (100). In the 16K and 14K alloys, a periodic antiphase domain structure of the AuCu II type ordered phase made a major contribution to age-hardening. An alternating coarse lamellar structure was formed by the mechanism of discontinuous precipitation in the 16K alloy, while a modulated structure by spinodal decomposition was observed in the 14K alloy.

Chemical Phenomena↗