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Biomedical subjects

Y Yasuda

Publications and source records attributed to Y Yasuda.

At least 271 records · Page 15Linked to original sources
PubMed1988

Studies on frequency-dependent attenuation in the normal liver and spleen and in liver diseases, using the spectral-shift zero-crossing method.

This report presents results of studies using the spectral-shift zero-crossing method to measure frequency-dependent attenuation (FDA) in normal liver and spleen and in diseased liver. We developed a new system for attenuation analysis that calculated FDA in dB/cm/MHz according to the following equation: (formula: see text). Data are collected from the region of interest on the scan image. Graphite-gel phantoms of known attenuation value are used to create a high degree of accuracy in this new system. Mean attenuation of normal livers was 0.55 +/- 0.05 dB/cm/MHz, while that of normal spleen was 0.37 +/- 0.06 dB/cm/MHz. No correlation between FDA and age could be seen. FDA was 0.81 +/- 0.17 dB/cm/MHz in fatty liver, 0.63 +/- 0.13 dB/cm/MHz in liver cirrhosis, and 0.64 +/- 0.12 dB/cm/MHz in chronic hepatitis. These values are higher than those obtained from normal liver, while tumor masses in the liver (hepatocellular carcinoma, hepatoblastoma, hemangioma) and diffuse infiltration by malignant lymphoma produced lower than normal values, averaging 0.38 +/- 0.08 dB/cm/MHz.

Adolescent↗
PubMed1988

Prolonged disturbance of consciousness with periodic EEG discharges after fulminant hepatitis.

Prolonged disturbance of consciousness associated with periodic EEG discharges developed in a 57-year-old male after fulminant hepatitis. He had repeated episodes with mutism and depersonalization, each lasting for 1-2 days. There were periodic EEG discharges during each episode. The atypical triphasic wave was a constituent of periodic EEG discharges together with spike and sharp waves, which suggests that the atypical triphasic wave has an epileptogenic factor as do spike and sharp waves. The effectiveness of anticonvulsants on the disturbance also suggests that there was an epileptogenic factor in the causation of the disturbance of consciousness.

Cognition Disorders↗
PubMed1988

Bilateral cheiro-oral syndrome following pontine haemorrhage.

Cheiro-oral syndrome is a peculiar sensory disturbance observed around the corner of the mouth and the palm of the hand on the same side, usually occurring unilaterally. A male patient with bilateral cheiro-oral syndrome following pontine haemorrhage is reported. CT, MRI and neurological findings showed that the syndrome was due to a lesion in the medial lemniscus and ventral secondary ascending tract of the trigeminal nerve on both sides. Although unilateral cheiro-oral syndrome has been reported with a lesion in the parietal lobe, thalamus or brain stem, a bilateral syndrome could be caused only by a lesion of the brain stem.

Cerebral Hemorrhage↗
PubMed1988

Preeclampsia: a microvesicular fat disease of the liver?

To study the interrelationship between preeclampsia, the syndrome of hemolysis, elevated liver enzymes, and low platelet count, and acute fatty liver of pregnancy, 41 liver specimens from 41 preeclamptic women with and without liver dysfunction were examined for the amount of fat deposited in hepatocytes. All 41 specimens stained with oil red O on frozen sections showed a significant amount of microvesicular fat droplets in varying degrees. In contrast, only 11 of the 41 stained conventionally (with hematoxylin-eosin) showed significant fatty infiltration. The density of hepatocellular fat correlated positively with plasma urate concentration and negatively with the platelet count. These findings suggest that preeclampsia may be one of several microvesicular fatty diseases of the liver and that acute fatty liver of pregnancy may be the most severe form.

Adult↗
PubMed1988

Long-term effects on male reproductive organs of prenatal exposure to ethinyl estradiol.

The effects of oral contraceptives on human offspring have not been established. This study shows the long-term effects of prenatal exposure to ethinyl estradiol, a common estrogenic component of oral contraceptives, on the testes and epididymides of aged mice. Five (83%) of the six aged male mice examined showed atrophy of seminiferous tubules, four (67%) had Leydig's cell hyperplasia, and one (17%) had precancerous changes in the epididymis. These phenomena may be results of decreases in testosterone content and its drastic conversion into estradiol-17 beta in the fetal testes at critical periods induced by ethinyl estradiol.

Aging↗
PubMed1988

7-[3-(4-[2,3-Dimethylphenyl]piperazinyl)propoxy]-2(1H)-quinolinone (OPC-4392), a presynaptic dopamine autoreceptor agonist and postsynaptic D2 receptor antagonist.

7-[3-(4-[2,3-dimethylphenyl]piperazinyl)propoxy]-2(1H)-quinolinone (OPC-4392), was synthesized in our laboratories and compared with apomorphine, 3-(3-hydroxyphenyl)-N-n-propylpiperidine (3-PPP) and dopamine antagonists in a series of tests designed to characterize dopamine receptor activation and inhibition. The assertion that OPC-4392 acts as an agonist at presynaptic dopamine autoreceptors is supported by the following behavioral and biochemical observations: OPC-4392, 3-PPP and apomorphine inhibited the reserpine-induced increase in DOPA accumulation in the forebrain of mice and in the frontal cortex, limbic forebrain and striatum of rats. In addition, the gamma-butyrolactone (GBL)-induced increase in DOPA accumulation in the mouse forebrain was also inhibited by OPC-4392, 3-PPP and apomorphine. Haloperidol antagonized the inhibitory effect of OPC-4392 in both instances. The inhibitory effect of OPC-4392 on GBL-induced DOPA accumulation lasted for at least 8 hours after oral administration to mice, while that of 3-PPP and apomorphine disappeared in 4 hours after subcutaneous injection. OPC-4392 failed to increase spontaneous motor activity in reserpinized mice, enhance spontaneous ipsilateral rotation in rats with unilateral striatal kainic acid (KA) lesions, induce contralateral rotation in rats with unilateral striatal 6-hydroxydopamine (6-OHDA) lesions and inhibit 14C-acetylcholine (Ach) release stimulated by 20 mM KCl in rat striatal slices. In addition, OPC-4392 appears to block postsynaptic D2 receptors since OPC-4392, as well as dopamine antagonists, was able to inhibit stereotyped behavior and climbing behavior induced by apomorphine in mice, displace the 3H-spiroperidol binding to rat synaptosomal membranes in vitro and reverse the inhibitory effect of apomorphine on Ach release in rat striatal slices. These results suggest that OPC-4392 acts as a dopamine agonist at presynaptic autoreceptors related to dopamine synthesis and acts as dopamine antagonist at postsynaptic D2 receptors.

Animals↗
PubMed1988

Functional analysis of an Epstein-Barr virus-nontransformed human B cell line.

A human B cell line, IW.2, was established from the culture of peripheral blood lymphocytes of a patient with chronic lymphocytic leukemia. IW.2 was shown to express IgM, B1 (CD20), and 12 (a major histocompatibility complex class II antigen) molecules on the cell membrane by analysis of flow microfluorometry (FMF) as well as a receptor for the third component of complement (C3R), but not to express an Epstein-Barr virus nuclear antigen. The cell growth of IW.2 was markedly inhibited when treated with either B cell stimulatory factor from phytohemagglutinin-conditioned medium or 12-O-tetradecanoylphorbol-13-acetate. Interestingly, IW.2 cells were capable of generating a significant amount of both IgM and IgG at the same time when stimulated with these reagents, followed by a decrease in the expression of IgM, B1, and I2 molecules on the cell membrane as well as C3R. The results suggest that IW.2 cells may be a model for the study of the maturation of human B cells.

Antibody-Producing Cells↗
PubMed1988

[Effect of position in the uterus on the fetal weight of the 21st day of pregnancy in the unilaterally ovariectomized rat].

Effects of intrauterine position of the fetuses on the weight of fetal sac, fetus and placenta were investigated on the 21th day of unilaterally (right) ovariectomized pregnant Wistar strain rats. Results were obtained as follows. 1. Litter size was negatively correlated with the mean weights of fetal sac and fetus. 2. The mean weights of male fetal sac and fetus were heavier than those of female ones, while there was no difference in the weight of placenta between male and female. 3. The mean weights of male fetal sac and fetus positioning ovarian end (OV) were lighter than those of ones at the other positions. And the highest frequency of the lightest weight of live fetuses was demonstrated at OV position. 4. The mean weights of male fetal sac and fetus positioning between two males (2M) were heavier than those of ones positioning not next to male (0M). And the mean weight of 2M female fetal sac was heavier than those of 0M one. 5. The mean weights of fetal sac and fetus positioning next to resorbed fetus were heavier than those of ones positioning not next to resorbed fetus.

Animals↗
PubMed1987

Establishment of an antigen-specific B cell clone by somatic hybridization.

Splenic B cells of A/J mice immunized with 2,4,6-trinitrophenyl (TNP)-lipopolysaccharide were fused with 2.52M, a mutant of a B cell line, in the presence of polyethylene glycol and dimethyl sulfoxide. TP67.21, a subclone of a resulting hybridoma, expresses IAk, IEk, IgM, B220, P50, and receptors for C3 fragment of complement, the Fc portion of IgG, and interleukin 2 receptor on the cell membrane; it also possesses receptor molecules for TNP on its surface, derived from TNP-reactive B cells of A/J mice primed with TNP-lipopolysaccharide used for somatic hybridization, by a rosette-forming assay with TNP-sheep erythrocytes. In contrast, parental 2.52M lacks IAk and IEk on the cell membrane and does not bind to TNP-sheep erythrocytes under the same conditions. Thus, it is likely that TP67.21 is an antigen-specific B cell clone directed against TNP. The antigen binding of cells was markedly inhibited by the specific free hapten or anti-IgM antibodies. Interestingly, TP67.21 was induced to generate a significant amount of anti-TNP antibody when treated with TNP conjugates including T cell-independent and -dependent antigens, such as TNP-lipopolysaccharide, TNP-bovine serum albumin, TNP-ovalbumin, and TNP-keyhole limpet hemocyanine in the absence of T cell help, as well as polyclonal activators; this was followed by a marked decrease in the expression of B cell surface markers on the cell membrane. This suggests that the cross-linkage of receptor molecules on TP67.21 by antigen may directly provide a differentiative signal for maturation to a lineage of B cells, and consequently results in the generation of antigen-specific antibodies without T cell involvement.

Animals↗
PubMed1987

Developmental anomalies induced by all-trans-retinoic acid in fetal mice: II. Induction of abnormal neuroepithelium.

All-trans-retinoic acid (RA) in olive oil was given in doses of 0, 40, or 60 mg/kg of body weight to pregnant mice on day 8 of gestation, and 2-6 hr later embryos were fixed in solutions with or without cetylpyridinium chloride (CPC). The neuroepithelium of the presumptive midbrain was processed for light and electron microscopy. Distorted contours of the neuroepithelium were induced by both doses of RA and the incidence and the severity of the disorganized neuroepithelium showed dose-related results. Abnormal neuroepithelium showed wide intercellular spaces with degenerated cytoplasmic processes or cell debris, separation of the apical side from adjacent cells, retention of mitotic and/or postmitotic cells on the apical side, presence of mitotic cells on the basal side, and detachment of degenerated structures from the neuroepithelium. Ultrastructurally, the affected neuroepithelium showed (1) appearance of degenerating filamentous or tubular coagulating bundles in the cytoplasm and the cytoplasmic process of the neural crest cells, (2) dispersal of polysomes into monosomes especially in the degenerating neural crest cells, (3) and a collecting of microfilament-like structures at the contact area between the neural crest cell and the presumptive neuroblast. These morphological changes suggest that RA affects the nature of cytoskeletal elements and the protein synthesis of the neuroepithelial cells. The selective susceptibility of neural crest cells to RA causes more degenerating neural crest cells in the neuroepithelium, which causes nonapproximation of the neural folds and scantiness of the migrating neural crest cells; these results lead to neural tube defects and craniofacial anomalies, respectively.

Actin Cytoskeleton↗
PubMed1987

Ovarian follicular cell hyperplasia in fetal mice treated transplacentally with ethinyl estradiol.

The occurrence of follicular cell hyperplasia was studied by light and electron microscopy in fetal mouse ovaries exposed to ethinyl estradiol (EE) from day 11 through day 17 of pregnancy. Pregnant mice were given EE in olive oil (0.02, or 0.2 mg/kg of body weight) and were sacrificed on day 18. The female fetuses were examined for ovarian histogenesis. Follicular cell hyperplasia was detected in both of the experimental groups, but the incidence was statistically significant only in fetuses exposed to 0.2 mg/kg of EE. Light and electron microscopic observations of the ovaries showed that the hyperplasia was located in the medullary region, and the follicular cells showed pleomorphism. Accumulation of abundant lipid droplets, enlarged rough endoplasmic reticulum with granular material, dense bodies, and vague masses of fibrous structures were seen in the cytoplasm. These morphological observations indicate that hyperplasia of follicular cells in fetal mouse ovaries at term can be induced by prenatal treatment with EE.

Abnormalities, Drug-Induced↗
PubMed1987

Prealbumin gene expression during mouse development studied by in situ hybridization.

Localization of prealbumin mRNA in tissues from mice at various stages of gestation was investigated using in situ hybridization procedures. Prealbumin mRNA was detected as early as the 10th day of gestation. It was specifically localized in endodermal cells of the visceral yolk sac, tela choroidea, and hepatocytes. In the adult mice, prealbumin mRNA was localized in the hepatocytes and choroid plexus epithelial cells. These observations indicate that synthesis of prealbumin mRNA is initiated in several different types of cells at early stages of fetal development.

Animals↗
PubMed1987

Development of Theileria sergenti in the haemolymph of the tick, Haemaphysalis longicornis.

The haemolymph of adult tick Haemaphysalis longicornis infected with Theileria sergenti, was examined at regulat intervals of time. As a result, kinetics could be detected in the haemolymph for the first time 25 days after the engorgement. The kinetics detected could be classified into three types on the basis of their morphological characteristics. They increased gradually in number, reaching a maximum 32 days later. Then they tended to decrease in number, disappearing almost completely from the haemolymph 44 days after the engorgement of ticks.

Animals↗
PubMed1987

Intraosseous lipoma of the skull: a report of two cases.

Case histories of a 12-year-old boy and a 20-year-old woman with hyperostosis of the frontoparietal bones are presented. Microscopical examination of the lesions showed intraosseous lipoma with hyperostosis of diploë. In both cases, only the prominent part of the tumor was removed for cosmetic reasons. The results were satisfactory, and there was no evidence of recurrence over a period of six years.

Adult↗