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Biomedical subjects

Y Nemoto

Publications and source records attributed to Y Nemoto.

At least 109 records · Page 6Linked to original sources
PubMed1994

IL-10 inhibits prostaglandin E2 production by lipopolysaccharide-stimulated monocytes.

Since IL-10 has recently been shown to exhibit pleiotropic effects on human monocytes, it was of interest to determine the effect of this cytokine on prostaglandin E2 (PGE2) production by monocytes. Recombinant IL-10 (rIL-10) did not significantly affect PGE2 production by lipopolysaccharide (LPS)-unstimulated monocytes, but efficiently inhibited PGE2 production by LPS-stimulated monocytes. The inhibition by rIL-10 was achieved in a dose-dependent manner. Recombinant IL-4 also inhibited PGE2 production at the same degree as rIL-10. Viral IL-10 inhibited PGE2 production by monocytes in a similar fashion as did human rIL-10. Endogenously produced IL-10 was also shown to inhibit PGE2 production by LPS-stimulated monocytes. Kinetic studies showed that the inhibition by rIL-10 on PGE2 production was observed at least 3 h after LPS stimulation. Taken together, these results indicate that IL-10 may play an important role in modulating immunological responses via down-regulation of PGE2 production by monocytes.

Cells, Cultured↗
PubMed1994

Adaptation of Aspergillus niger to several antifungal agents.

Adaptation of Aspergillus niger to short-term stress induced by three antifungal agents [amphotericin B (AMPH), miconazole (MCZ), and ketoconazole (KCZ)] was observed and evaluated quantitatively using individual hyphae. Spores were inoculated onto a poly-L-lysine-coated glass plate making up the base of a culture vessel. Potato dextrose broth (PDB) was added and the vessel incubated for 24 h at 28 degrees C. The growth rate of an arbitrarily selected test hypha was measured automatically. Exposure to AMPH (0.075 micrograms ml-1) stopped the growth of the hypha. After washing with PDB, the same concentration of AMPH was applied again. The growth of the test hypha was not inhibited. This phenomenon was defined as adaptation to the short-term stress of AMPH. Similarly, adaptation was observed with MCZ (0.01 microgram ml-1) and KCZ (0.5 microgram ml-1). The time required for the test hypha to restart growth after washing with PDB depended upon the concentration of MCZ or KCZ, but not upon the concentration of AMPH.

Adaptation, Physiological↗
PubMed1994

A case of 17 alpha-hydroxylase deficiency with retained menstruation.

A patient with 17 alpha-hydroxylase deficiency (17OHD) who continued to menstruate is reported. A 24-year-old woman who presented with hypertension, hypokalemia and irregular menses had increased plasma ACTH and mineralocorticoids without any increase in glucocorticoids or sex steroids, and a bilateral adrenal enlargement on abdominal X-ray CT. ACTH stimulation test revealed hyperresponse of the metabolites of the mineralocorticoid pathway and blunted or absent response of those of the glucocorticoid and androgen pathway. Almost all of the abnormalities disappeared after dexamethasone administration. While 17OHD is usually known to accompany hypergonadotropic hypogonadism, the patient continued to menstruate, though irregularly. Although human chorionic gonadotropin administration failed to induce response, basal plasma levels of ovarian steroid (estradiol) and gonadotropins as well as response to LHRH stimulation test were all normal. Thus, the clinical and biochemical features of this case is compatible with the partial deficiency of both adrenals and ovaries, being less severe in the latter. A further analysis especially at molecular level is needed to elucidate the basis for the heterogeneity of this disorder.

Adrenal Hyperplasia, Congenital↗
PubMed1994

[Observation of the eyelid structure with opening and closing of the eye in magnetic resonance imaging].

To confirm the changes in the upper eyelid structure during normal movements such as opening and closing we observed the changes with magnetic resonance imaging and obtained the following results. (1) In the anterior lobe of the upper eyelid, the lower part moves more than the upper part. (2) The tarsus slides toward posterior and upper direction when the eye opens. (3) The orbital septum and the orbital fat move posteriorly and thicken when the eye opens. (4) When the eye opens Whitnall's ligament moves posteriorly with a little change of the acting vector direction of the levator muscle. (5) Aponeurosis of the levator muscle clearly separates from Müller's muscle when the eye opens. (6) We suspected that there is some suspending tissue of Whitnall's ligament that consists of a membranous or mesh-like structure in the orbital fat above the levator muscle.

Adult↗
PubMed1993

ADP-ribosylation of rho p21 inhibits lysophosphatidic acid-induced protein tyrosine phosphorylation and phosphatidylinositol 3-kinase activation in cultured Swiss 3T3 cells.

Botulinum C3 exoenzyme was used to specifically ADP-ribosylate and inactivate rho p21, and the effects of rho p21 inactivation on lysophosphatidic acid (LPA)-induced tyrosine phosphorylation were examined in cultured Swiss 3T3 cells. LPA induced a rapid increase in the tyrosine phosphorylation of a number of proteins. Pretreatment of the cells with the C3 exoenzyme caused ADP-ribosylation of rho p21 in the cells and selectively attenuated the phosphorylation of several proteins, including p43 mitogen-activated protein kinase, p125 focal adhesion kinase, and two proteins of 72 and 88 kDa. C3 exoenzyme pretreatment did not block the initial phosphorylation and activation of mitogen-activated protein kinase but suppressed its subsequent rise. In contrast, the enzyme treatment inhibited the induction of phosphorylation of the 72- and 88-kDa proteins and suppressed the basal and LPA-induced tyrosine phosphorylation of p125 focal adhesion kinase. In addition, immunoprecipitation of cell lysates with an antibody directed against the 85-kDa subunit of phosphatidylinositol 3-kinase (PI 3-kinase) co-precipitated a tyrosine-phosphorylated band of 180 kDa. C3 exoenzyme pretreatment suppressed both the phosphorylation of this band and PI 3-kinase activation associated with LPA stimulation. These findings suggest that rho p21 works as a link between the LPA receptor signal and the subsequent tyrosine phosphorylation and PI 3-kinase activation in these cells.

3T3 Cells↗
PubMed1993

Development of a flow system for the microscopic observation of cultured nerve cells and its application to the neurite growth control of PC12h-R.

A flow system has been developed for the continual microscopic observation of cultured nerve cells. The undefined effects of coexisting cells could be efficiently reduced by the continuous flow of a medium. The present flow system was useful also for the experiments requiring medium exchanges. Its performance was demonstrated by the repeated actions of NGF or db-cAMP to PC12h-R cells. The neurite projection and its retraction were repeatedly observed by the supply and the removal of those factors.

Animals↗
PubMed1993

Participation of poly(ADP-ribose) synthetase in the process of norepinephrine-induced inhibition of major histocompatibility complex class II antigen expression in human astrocytoma cells.

We previously demonstrated that the expression of a transfected poly(ADP-ribose) synthetase cDNA into macrophage tumor cells inhibited interferon-gamma-dependent induction of major histocompatibility complex(MHC) class II antigens. In the present study, we found that addition of norepinephrine to the cultured human astrocytoma STTG1 cells induced mRNA of poly(ADP-ribose) synthetase in 6-14h. Thus, we cultured the cells in the presence of norepinephrine for 24h, and then induced the MHC class II antigen by the addition of interferon-gamma. The expression of MHC class II antigen was inhibited, whereas it was not inhibited when norepinephrine and interferon-gamma were simultaneously added into the culture medium. These results suggest that an increase of poly(ADP-ribose) synthetase by norepinephrine cause the inhibition of interferon-gamma-mediated MHC class II antigen expression.

Astrocytoma↗
PubMed1993

[MR imaging of infectious spondylitis--usefulness of Gd-DTPA].

The aim of this study was to determine the usefulness of MR images obtained with gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) in cases of infectious spondylitis. In our study, four of seven patients were suffering from pyogenic spondylitis while the remaining three had tuberculous spondyitis. In comparison with noncontrast MR images, contrast MR images improved the delineation of disk space infection, extension of the lesions into paravertebral muscles, and the spinal canal, but demarcation of vertebral body lesions and extension of paravertebral fat tissue became less obvious. In the four patients who had pyogenic spondylitis, contrast MR images showed localized, intense vertebral body enhancement adjacent to the end plate and its communication with disk or paravertebral enhancement. In the three patients who had tuberculous spondylitis, contrast MR images showed geographic and/or ring-like enhancement of the vertebral body. We concluded that contrast MR images might be useful for better understanding the pathophysiology of infectious spondylitis and differentiating between tuberculous and pyogenic spondylitis.

Adult↗
PubMed1993

[Discarding medical images and its evaluation].

Following a survey of our filing system, the period of storage of medical images was generally limited to ten years, a system which was put into execution in 1990. Film jackets older than ten years are discarded every year, except for those registered for permanent storage. Fourteen thousand jackets (6.5% of total) have been registered for permanent storage. A follow-up survey has been performed to evaluate this system. The survey focused mainly on the frequency of re-issue of film jackets, and the rate of access to jackets. Discarded jackets now number about 50,000, a reduction of 20%. A total of 405 jackets were re-issued in a year due to the re-examination of patients whose jackets had been discarded. The annual number of re-called jackets from the repository outside our hospital was about 2,200 (about 500 of them were for research work), which corresponded to 1.5% of the patients re-examined in the radiology department. The new filing system has been well integrated into the hospital daily routine. Information cost was calculated as a function of access rate to the stored information, and the concept of "cost-of-information" was proposed as a measure of cost analysis of an information system.

Costs and Cost Analysis↗
PubMed1993

Determination of anti-Aspergillus activity of antifungal agents based on the dynamic growth rate of a single hypha.

The dynamic growth rate of a single hypha of Aspergillus niger was analysed using an automatic system. A colony of A. niger was in contact with saline, saline containing an antifungal agent, and flushing saline, in sequence. The growth rate of a test hypha selected arbitrarily from the colony responded dynamically to the antifungal agent. The minimum concentration that caused the complete inhibition of hyphal growth was defined as the minimum inhibitory concentration (MIC). The MIC values obtained were compared with those determined by conventional methods based on increasing rate of colony diameter or dry matter weight.

Amphotericin B↗
PubMed1993

Effect of coexisting cells on the NGF-inducing neurite growth from PC12h-R.

Possible roles of coexisting cells in inducing neurite growth from a nerve cell were studied. Nerve growth factor (NGF)-inducing neurite growth from PC12h-R (a cell line derived from cultured nerve cells) was investigated at various cell densities. At the cell density 10(2)-10(4) cells/ml neurites appeared even without NGF. In contrast, no neurite appeared without NGF in single cell culture. The neurite growth observed in plural cell culture without NGF was only partially inhibited by antibody to NGF receptor (Ab-NGFR). However, the effect of the used medium alone was mostly inhibited by Ab-NGFR. These results suggest that the neurite inducing potency of coexisting cells is via different sites than the NGF receptor.

Animals↗
PubMed1993

R2D5 antigen: a calcium-binding phosphoprotein predominantly expressed in olfactory receptor neurons.

R2D5 is a mouse monoclonal antibody that labels rabbit olfactory receptor neurons. Immunoblot analysis showed that mAb R2D5 recognizes a 22-kD protein with apparent pI of 4.8, which is abundantly contained in the olfactory epithelium and the olfactory bulb. We isolated cDNA for R2D5 antigen and confirmed by Northern analysis and neuronal depletion technique that R2D5 antigen is expressed predominantly, but not exclusively, in olfactory receptor neurons. Analysis of the deduced primary structure revealed that R2D5 antigen consists of 189 amino acids with calculated M(r) of 20,864 and pI of 4.74, has three calcium-binding EF hands, and has possible phosphorylation sites for Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) and cAMP-dependent protein kinase (A kinase). Using the bacterially expressed protein, we directly examined the biochemical properties of R2D5 antigen. R2D5 antigen binds Ca2+ and undergoes a conformational change in a manner similar to calmodulin. R2D5 antigen is phosphorylated in vitro by CaM kinase II and A kinase at different sites, and 1.81 and 0.80 mol of Pi were maximally incorporated per mol of R2D5 antigen by CaM kinase II and A kinase, respectively. Detailed immunohistochemical study showed that R2D5 antigen is also expressed in a variety of ependymal cells in the rabbit central nervous system. Aside from ubiquitous calmodulin, R2D5 antigen is the first identified calcium-binding protein in olfactory receptor neurons that may modulate olfactory signal transduction. Furthermore our results indicate that olfactory receptor neurons and ependymal cells have certain signal transduction components in common, suggesting a novel physiological process in ependymal cells.

Animals↗
PubMed1993

Maturational changes of urinary growth hormone excretion in the premature infant.

High plasma GH concentrations are observed in the newborn infant. To characterize the maturational change of GH secretion in premature infants, we serially measured 24-h urinary GH excretion in 30 premature infants. The gestational age ranged from 25-37 weeks and birth weight from 468-2415 g. Urinary GH excretion at 1 week of age was negatively correlated with gestational age, birth weight, and length of infants with adequate intrauterine growth. In the infants with 27 weeks of mean gestation (range, 25-28 weeks) mean urinary GH excretion was highest (6.1 micrograms/day) at the first week, decreased to 1.2 micrograms/day by the fourth week, and remained between 0.05 and 0.18 micrograms/day thereafter. When compared to the corresponding conceptional age, there was no postnatal difference in the pattern of GH excretion between infants with 27 and 31 (range, 29-32) weeks of mean gestational age. Persistent hyperexcretion of GH was observed in 4 of the 5 infants with intrauterine or postnatal growth retardation. Our results suggest that the postnatal change of 24-h urinary GH excretion is similar to ontogenic changes of plasma GH in fetus, and GH may have some effects on postnatal growth in premature infants.

Aging↗
PubMed1993

Thyroid dysfunction in isolated adrenocorticotropic hormone (ACTH) deficiency: case report and literature review.

A case of isolated ACTH deficiency accompanying transient primary hypothyroidism was reported along with a review of literature on isolated ACTH deficiency in Japan with special reference to its association with thyroid function. Our case, a 56-year-old woman, developed somnolence and hypoglycemia due to isolated ACTH deficiency. She also had the features of hypothyroidism, namely mounding phenomenon, muscle rigidity, increased plasma myogenic enzymes and cold intolerance. Both free T3 and free T4 were decreased, and basal as well as TRH-stimulated TSH levels were abnormally high. Plasma thyroglobulin was increased and no anti-thyroid antibodies were detected. All thyroid related physical and biochemical abnormalities disappeared after hydrocortisone replacement. A review of the literature on 103 cases disclosed that more than half the cases with isolated ACTH deficiency had a high plasma level of TSH, basal and/or TRH-induced, while the antithyroid antibodies were reported to be positive in only 13 cases. In more than 70% of such cases, the abnormality in the pituitary-thyroid axis was transient and was reversed by glucocorticoid replacement. Our case and cases in the literature indicate that the interference of thyroid hormone synthesis and/or secretion by glucocorticoid deficiency per se is the major cause of thyroid dysfunction rather than associated autoimmune thyroid disease.

Adolescent↗
PubMed1992

A rho gene product in human blood platelets. I. Identification of the platelet substrate for botulinum C3 ADP-ribosyltransferase as rhoA protein.

A substrate protein for botulinum C3 ADP-ribosyltransferase (C3 exoenzyme) in human platelets was purified to apparent homogeneity from the cytosol by ammonium sulfate fractionation and successive chromatography on columns of DEAE-Sepharose, hydroxylapatite, phenyl-Sepharose, and TSK phenyl-5PW. The purified protein yielded an amino acid sequence identical to that of rhoA protein. When platelet cytosol and membranes were incubated with C3 exoenzyme and [32P]NAD and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing, they gave only one [32P]ADP-ribosylated band on each electrophoresis that showed an M(r) of 22,000 and a pI of 6.0. The radioactive bands from the two fractions co-migrated with each other and with the [32P]ADP-ribosylated purified protein. When these radioactive products were partially digested with either alpha-chymotrypsin or trypsin and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the same digestion pattern was found in the three samples. These results suggest that the ADP-ribosylation substrate for C3 exoenzyme in the platelet cytosol and membrane is rhoA protein and that it is the sole substrate detectable in human platelets.

ADP Ribose Transferases↗
PubMed1992

NAD+ binding site of Clostridium botulinum C3 ADP-ribosyltransferase. Identification of peptide in the adenine ring binding domain using 2-azido NAD.

C3 ADP-ribosyltransferase is an exoenzyme produced by certain strains of Clostridium botulinum types C and D, which specifically ADP-ribosylates rho proteins in eukaryotic cells. Using the photoaffinity probe [alpha-32P]nicotinamide-2-azidoadenine dinucleotide, we have identified the adenine ring binding domain of the NAD+ binding site. The specificity of labeling was demonstrated by saturation effects and protection by the natural compound at physiologically relevant concentrations. Saturation of labeling was observed at 50 microM. Protection experiments indicated an 80% protection of labeling by 100 microM NAD+ when protein was photolyzed in the presence of 10 microM probe. Trypsin or Staphylococcus aureus V8 protease digestion of the photolabeled protein, along with boronate affinity chromatography and immobilized metal affinity chromatography, was used to specifically isolate the peptide region photolabeled with the probe. The peptide corresponded to Phe9-Gly19 near the N terminus.

ADP Ribose Transferases↗
PubMed1992

[Magnetic resonance (MR) imaging of chordoma and chondroma in the skull base--differential diagnosis by IR sequence].

Differential diagnosis of chordoma and chondroma in the skull base is sometimes difficult. We retrospectively reviewed the MR images of 14 patients with skull base tumors (nine chordomas, four chondromas and one chondrosarcoma). MR imaging was performed with a 0.5 Tesla system (Picker International). Inversion recovery (IR) (2500-2100/600-500/40), T1-weighted spin echo (SE) (800-600/40), and T2-weighted SE (2500-1800/120) images were obtained. On IR images, seven of eight chordomas showed heterogeneous low signal intensity, and one chordoma and all chondromas showed markedly low signal intensity similar to that of CSF. Calcified or ossified portions of the chondromas were demonstrated as areas of moderately low intensity on IR images. Chondrosarcoma showed moderately low intensity similar to that of chordoma. T1-weighted SE images of chordoma and chondroma showed no difference in signal intensity. On T2-weighed SE images, six of nine chordomas and all chondromas showed markedly high signal intensity. Three chordomas and one chondrosarcoma showed moderately high signal intensity. In the diagnosis of skull base tumors, the IR sequence seems to be useful for differentiating chondroma from chordoma.

Adolescent↗