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Biomedical subjects

N Suzuki

Publications and source records attributed to N Suzuki.

At least 145 records · Page 8Linked to original sources

Metabolic activation of bisphenol A by rat liver S9 fraction.

Bisphenol A (BPA) is a well-known endocrine-disrupting chemical found in the environment. To assess the metabolic modulation of estrogenic activity of BPA after ingestion, we investigated whether the incubation of BPA with rat liver S9 fraction results in metabolic activation or inactivation of estrogenic activity using a recombinant yeast expressing human estrogen receptor and MCF-7 transfected firefly luciferase plasmid for a reporter assay. When 0.1 mM BPA was incubated with rat liver S9 for 1 h, the estrogenic activity was increased about two to five times compared with that of the control, in which the S9 was inactivated prior to incubation. This metabolic activation was inhibited by SKF 525-A, an inhibitor of cytochrome P450. With increasing incubation time, the estrogenic activity increased time-dependently. Interestingly, however, the metabolic activation did not proceed with either microsomes or cytosol alone and was restored by a recombination of both fractions. The active metabolite was eluted at later retention time than that of BPA on HPLC with a reversed-phase column. Bisphenol B and methoxychlor were also activated by incubation with rat liver S9, whereas 4-tert-octylphenol and 4-nonylphenol, as well as 17beta-estradiol, were metabolically inactivated. The present results clearly indicate that BPA is metabolically activated in terms of estrogenicity under the conditions existing only with combined rat liver microsomes and cytosol.

Animals↗

Expression of Babesia equi merozoite antigen 1 in insect cells by recombinant baculovirus and evaluation of its diagnostic potential in an enzyme-linked immunosorbent assay.

The gene encoding the entire Babesia equi merozoite antigen 1 (EMA-1) was inserted into a baculovirus transfer vector, and a recombinant virus expressing EMA-1 was isolated. The expressed EMA-1 was transported to the surface of infected insect cells, as judged by an indirect fluorescent-antibody test (IFAT). The expressed EMA-1 was also secreted into the supernatant of a cell culture infected with recombinant baculovirus. Both intracellular and extracellular EMA-1 reacted with a specific antibody in Western blots. The expressed EMA-1 had an apparent molecular mass of 34 kDa that was identical to that of native EMA-1. The secreted EMA-1 was used as an antigen in an enzyme-linked immunosorbent assay (ELISA). The ELISA differentiated B. equi-infected horse sera from Babesia caballi-infected horse sera or normal horse sera. The ELISA was more sensitive than the complement fixation test and IFAT. These results demonstrated that the recombinant EMA-1 expressed in insect cells might be a useful diagnostic reagent for detection of antibodies to B. equi.

Animals↗

Identification of Actinobacillus actinomycetemcomitans serotypes by multiplex PCR.

Oligonucleotide primers specific for gene clusters involved in the biosynthesis of serotype-specific polysaccharide antigens were designed to identify Actinobacillus actinomycetemcomitans serotypes a to e using the multiplex PCR. This method may be useful for serotype-specific genotyping rapidly and directly from clinical samples containing various organisms.

Actinobacillus Infections↗

Difference in B cell activation between dermatomyositis and polymyositis: analysis of the expression of RP105 on peripheral blood B cells.

BACKGROUND: It has previously been shown that RP105, a new B cell surface protein, is lost in activated human B cells. OBJECTIVE: To investigate whether there is a difference in B cell activation between patients with dermatomyositis (DM) and those with polymyositis (PM) using RP105 as a marker. METHODS: The population of RP105 negative B cells (activated B cells) in the peripheral blood mononuclear cells of seven patients with dermatomyositis (DM) and 11 with polymyositis (PM) was analysed by flow cytometry. RESULTS: The percentage of RP105 negative B cells in the peripheral blood of patients with PM was low (5.8 (SD 2.4)%), similar to that of normal subjects. In contrast, all patients with DM showed increased RP105 negative B cell populations (33.0 (6.9)%). Bronchoalveolar lavage fluid from a patient with DM and active interstitial pneumonitis contained a large number of RP105 negative B cells. CONCLUSION: These findings suggest that the expansion of RP105 negative B cells is a hallmark of DM, and that B cell activation in DM may be pathogenetically different from that in PM.

Adult↗

A novel function of prolactin-releasing peptide in the control of growth hormone via secretion of somatostatin from the hypothalamus.

The present study examined a novel function of PRL-releasing peptide (PrRP) on the neuroendocrine. PrRP-immunoreactive nerve fibers and nerve terminals were located in the vicinity of the somatostatin (SOM)-neurons in the hypothalamic periventricular nucleus (PerVN). Immuno-electron microscopy revealed that PrRP-immunoreactive nerve terminals made synaptic contacts with nonimmunoreactive neuronal elements in the PerVN. Intracerebroventricular (icv) administration of PrRP induced immediate early gene, NGFI-A, in SOM-neurons in the PerVN. Double-labeling in situ hybridization showed that some parts of SOM-neurons in the PerVN expressed PrRP receptor messenger RNA. Therefore, some parts of SOM-neurons in the PerVN are considered to be directly innervated by PrRP via PrRP receptor. In addition to the above morphological characteristics, icv administration of PrRP decreased plasma GH levels. Such inhibitory effects of PrRP on the secretion of GH from the anterior pituitary were diminished by depletion or neutralization of SOM. From these findings it was strongly suggested that SOM-neurons respond to PrRP and secrete SOM into the portal vessels and thus inhibit GH secretion from the anterior pituitary.

Animals↗

Developmentally delimited emergence of more orderly luteinizing hormone and testosterone secretion during late prepuberty in boys.

To quantitate changing feedback control in the GnRH-LH/FSH-testosterone axis in male puberty, we here quantitate the orderliness of hormone release patterns using the regularity (pattern-sensitive) statistic, approximate entropy (ApEn), in 46 eugonadal boys representing 6 genitally defined stages of normal puberty. ApEn is a single variable, model-free, and scale-independent barometer of coordinate signaling or integrative regulation within a coupled neuroendocrine axis. Accordingly, we quantitated ApEn of LH profiles obtained by immunofluorometric assay of sera sampled every 20 min for 24 h. LH ApEn declined remarkably between early prepuberty (genital stage I-A: mean bone age, 4.6 +/- 1.6 yr; testis volume, <3 mL for at least 3 succeeding yr) and late prepuberty (genital stage I-C: bone age, 8.7 +/- 1.8 yr; testis volume, <3 mL for up to 1 yr thereafter; P: = 0.00019), which indicates the acquisition of more regular LH release patterns in late prepuberty. Maximal LH orderliness occurred in puberty stage II (bone age, 10.7 +/- 1.0 yr; testis volume, 2.8 +/- 0.4 mL). The LH secretory process was more disorderly in mid- and later puberty (Tanner stages III and IV). Transpubertal variations in testosterone ApEn manifested a similar tempo, i.e. the greatest regularity of testosterone secretion (lowest ApEn) emerged in Tanner genital stage II (P: < 10(-)(7)), with less orderly patterns evident both earlier and later in sexual development. In contrast, FSH ApEn values remained invariant of pubertal status. Analysis of bihormonal coupling using the theoretically related bivariate cross-ApEn statistic disclosed maximal 2-hormone synchrony for LH and testosterone secretion in genital stage II (P: = 0.031), with relative deterioration of coordinate LH and testosterone release patterns both before and after. LH and FSH release became maximally synchronous at the end of prepuberty (genital stage I-C; P: = 0.029), and FSH and testosterone synchrony peaked in pubertal stage III (P: = 0.037). As mean 24-h serum concentrations of LH, FSH, and testosterone rose transpubertally by 35-fold (LH), 68-fold (FSH), and 70-fold (testosterone), respectively, we infer that pubertal developmental stage per se rather than level of hormone output dictates coordinate GnRH-LH/FSH-testosterone secretion. In summary, in eugonadal boys, the regularity of 24-h LH and testosterone secretory patterns undergoes well defined pubertal stage-specific control. No sexually developmentally delimited regulation is inferable for FSH. The concept of temporally biphasic puberty-dependent variations in neurohormone secretory regularity contrasts with the unidirectional rise in daily hormone output. Accordingly, we infer that late prepuberty and early puberty (Tanner genital stages IC and II) embody a physiologically unique sexual developmental window, marked by transiently enhanced LH and testosterone feedback stability in boys. Whether analogous plasticity of hypothalamo-pituitary-gonadal interactions unfolds during female adolescence is not known.

Child↗

Secretory transport of p-aminohippuric acid across intestinal epithelial cells in Caco-2 cells and isolated intestinal tissue.

The intestinal transport of an organic anion, p-aminohippuric acid (PAH), was studied in Caco-2 cell monolayers and rat intestinal tissue mounted in Ussing chambers. In both experimental methods, PAH exhibited vectorial transport with significantly greater permeability in the secretory direction than the absorptive direction, indicating net secretion. This secretory transport required metabolic energy, but protons or hydroxyl ions were not involved as the driving force. In Caco-2 monolayers, secretory transport of [3H]PAH was decreased, and the intracellular accumulation of PAH was increased with increasing concentration of unlabelled PAH at the basolateral side. Addition of probenecid and genistein at the basolateral side decreased the secretory transport of [3H]PAH; the accumulation was not changed by probenecid, but was increased by genistein. In addition, the initial uptake rate of [3H]PAH from the basolateral side was decreased by both PAH and probenecid, but not by genistein. Therefore, it is suggested that the transport of PAH in Caco-2 cells is regulated by several transporters: a genistein-sensitive transporter on the apical membrane and probenecid-sensitive transporters on both the basolateral and apical membranes. In rat intestinal tissues, the transport rate of PAH showed regional variation (ileum > jejunum > duodenum), suggesting that secretory transporters with high activity exist predominantly in the lower region of the small intestine. The results suggest that PAH transport in both Caco-2 cells and rat intestinal tissues is regulated by multiple transporters on the apical and basolateral membranes, and these transporters have different characteristics.

Animals↗

Active intestinal secretion of new quinolone antimicrobials and the partial contribution of P-glycoprotein.

Transport of quinolone antimicrobials and the contribution of the secretory transporter P-glycoprotein were studied in-vivo and in-vitro. In rat intestinal tissue (Ussing chambers method) and human Caco-2 cells (Transwell method), grepafloxacin showed secretory-directed transport. In both experimental systems, the secretory-directed transport was decreased by ciclosporin A, an inhibitor of P-glycoprotein, and probenecid, an inhibitor of anion transport systems. This suggested the contribution of P-glycoprotein and anion-sensitive transporter(s). The involvement of P-glycoprotein was investigated by using a P-glycoprotein over-expressing cell line, LLC-GA5-COL150, and P-glycoprotein-gene-deficient mice (mdr1a(-/-)/1b(-/-) mice). LLC-GA5-COL150 cells showed secretory-directed transport of grepafloxacin, while the parent cell line, LLC-PK1, did not. The secretory-directed transport of sparfloxacin and levofloxacin was also detected in LLC-GA5-COL150 cells. In the mdr1a(-/-)/1b(-/-) mice, the intestinal secretory clearance was smaller than that in wild-type mice after intravenous administration of grepafloxacin. Moreover, the absorption from an intestinal loop in mdr1a(-/-)/1b(-/-) mice was larger than that in wild-type mice. Accordingly, it appears that some quinolones are transported by secretory transporters, including P-glycoprotein. The involved transporters function in-vivo not only to transport grepafloxacin from blood to intestine but also to limit its intestinal absorption.

ATP Binding Cassette Transporter, Subfamily B↗

Increase of cGMP, cADP-ribose and inositol 1,4,5-trisphosphate preceding Ca(2+) transients in fertilization of sea urchin eggs.

Transient increases, or oscillations, of cytoplasmic free Ca(2+) concentration, [Ca(2+)](i), occur during fertilization of animal egg cells. In sea urchin eggs, the increased Ca(2+) is derived from intracellular stores, but the principal signaling and release system involved has not yet been agreed upon. Possible candidates are the inositol 1,4,5-trisphosphate receptor/channel (IP(3)R) and the ryanodine receptor/channel (RyR) which is activated by cGMP or cyclic ADP-ribose (cADPR). Thus, it seemed that direct measurements of the likely second messenger candidates during sea urchin fertilization would be essential to an understanding of the Ca(2+) signaling pathway. We therefore measured the cGMP, cADPR and inositol 1,4,5-trisphosphate (IP(3)) contents of sea urchin eggs during the early stages of fertilization and compared these with the [Ca(2+)](i) rise in the presence or absence of an inhibitor against soluble guanylate cyclase. We obtained three major experimental results: (1) cytosolic cGMP levels began to rise first, followed by cADPR and IP(3) levels, all almost doubling before the explosive increase of [Ca(2+)](i); (2) most of the rise in IP(3) occurred after the Ca(2+) peak; IP(3) production could also be induced by the artificial elevation of [Ca(2+)](i), suggesting the large increase in IP(3) is a consequence, rather than a cause, of the Ca(2+) transient; (3) the measured increase in cGMP was produced by the soluble guanylate cyclase of eggs, and inhibition of soluble guanylate cyclase of eggs diminished the production of both cADPR and IP(3) and the [Ca(2+)](i) increase without the delay of Ca(2+) transients. Taken together, these results suggest that the RyR pathway involving cGMP and cADPR is not solely responsible for the initiating event, but contributes to the Ca(2+) transients by stimulating IP(3) production during fertilization of sea urchin eggs.

Adenosine Diphosphate Ribose↗

Structures of new sesquiterpenoids from Farfarae Flos.

Two new bisabolane-type sesquiterpenoids, (3R,4R,6S)-3,4-epoxybisabola-7(14),10-dien-2-one and (1R,3R,4R,5S,6S)-1-acetoxy-8-angeloyloxy-3,4-epoxy-5-hydroxybisabola-7(14),10-dien-2-one, and a new oplopane-type sesquiterpenoid, 14(R)-hydroxy-7beta-isovaleroyloxyoplop-8(10)-en-2-one, were isolated from Farfarae Flos along with three known compounds. The structures of these compounds were elucidated on the basis of spectroscopic evidence.

Acetylation↗

Intercalation compounds of layered materials for drug delivery use. II. Diclofenac sodium.

Intercalation compounds of ternary layered inorganic materials, synthetic mica (Na-TSM), with diclofenac sodium (DFS) and its drug release characteristics were investigated. Hygroscopic DFS was selected as a model drug to verify the anti-humidity and anti-oxidation of the intercalation compounds. Na-TSM powder was first mixed with the reduced-type phosphatidylcholine (H-PC) solution of chloroform or ethanol. DFS was then mixed with these solutions and heated at 37 degrees C to prepare the ternary Na-TSM/H-PC/DFS compound. A remarkable phenomenon was observed in the drug release study. The net amount of DFS from the DFS powder decreased apparently after 20 min arising from the decomposition of DFS in acidic medium. On the other hand, the net amount of the released DFS from the intercalation compound was invariant. Thermal analyses study indicated that DFS powder was hygroscopic and a significant endothermic peak was observed accompanied by a large weight loss due to the dehydration of adsorbed water from 40 to 90 degrees C. On the other hand, no significant dehydration reaction was observed in the intercalation compounds even in the sample stored under humid conditions. The present results indicated that the ternary intercalation compound was resistant to acid in addition to anti-humidity.

Aluminum Silicates↗

Characterization of aryl alcohol oxidase produced by dye-decolorizing fungus, Geotrichum candidum Decl.

Aryl alcohol oxidase (AAO) produced by Geotrichum candidum Dec1 (Dec1), a newly isolated decolorizing fungus, was purified by ultrafiltration and by using diethylaminoethyl (DEAE) Sephacel, Butyl-Toyopearl and Mono-Q columns. H2O2 produced by concomitant AAO oxidation of veratryl alcohol (VA) to veratraldehyde was consumed by a peroxidase (DyP) purified from Dec1 culture, leading to the decolorization of a dye (in vitro). In the liquid culture of Dec1, the existence of H2O2 and veratraldehyde was confirmed during cultivation, when dye-decolorization and AAO activities were maintained. This indicates that VA produced by Dec1 was oxidized by AAO to veratraldehyde, generating H2O2, which supported dye-decolorizing activity of Decl in vivo. The prevention of polymerization of DyP oxidation products of a dye in the presence of AAO was shown.

Journal Article↗

Brief note and evaluation of acute-radiation syndrome and treatment of a Tokai-mura criticality accident patient.

Patient A who was exposed to a critical dose of radiation developed skin lesions throughout the body surface, gastrointestinal disorder with massive diarrhea and prominent bleeding, which caused severe loss in body fluids. Gastrointestinal bleeding due to the deteriorated intestinal mucosa was considered to be one of the major causes of death, although infection did not develop, possibly because of SDD and aseptic intensive care, until terminal stages. Patient A ultimately developed respiratory and renal failure in addition to skin exudate and gastrointestinal bleeding, and died of multiple organ failure on the 83rd day after exposure. The extreme unevenness of the dose distribution and the neutron versus y-ray component made the clinical manifestation very complicated. Initially, the mean absorbed dose was calculated as 16-20 GyEq for Patient A, mainly based on neutron-activated 24Na in the blood. However, a very recent calculation showed that the absorbed skin dose was highest at the upper-right abdomen reaching 61.8 Gy (27.0 as neutron plus 34.8 Gy as y-ray). The dorsal side was calculated to have received one eighth of the value of the abdominal side, and much smaller neutron component. His absorbed-dose distribution throughout the body was very inhomogeneous because of the closeness of the standing point to the mixing tank. Despite prolonged survival because of intensive care with massive fluids and blood transfusion, peripheral blood stem-cell transplantation, cultured skin-cell grafts, and the administration of cytokines for marrow, the patient was not saved. Restoration of the bone marrow function, prevention of skin fibrosis, radiation lung damage, and repair of gastrointestinal mucosa, and final recovery of the patient were elusive. Abundant personnel and resources were also a prerequisite to allow for the comprehensive and collective intensive care. A further understanding of the effects of high-dose radiation as well as the basic and clinical development of regeneration medicine are important issues for the future.

Adult↗

Accelerative effect of olive oil on liver glycogen synthesis in rats subjected to water-immersion restraint stress.

The effects of dietary oils on stress-induced changes in the liver glycogen metabolism of male Wistar rats at 6 weeks of age were investigated. The rats were subjected to repetitive water-immersion restraint and fed with a 20% saturated fatty acid mixture (PSC), olive oil (OLI), safflower oil (SAF), or linseed oil (LIS) diet. Stress loading decresed the body weight gain, although the food intake was hardly changed, and the weights of the liver and spleen generally declined regardless of the elapsed time after stress loading and the type of dietary oil. The adrenal weight was generally enhanced by stress in all deitary groups, and particularly tended to be greater in the OLI and PSC groups than in the other two. The plasma corticosterone concentration increased immediately after stressing (Stress-1), but approached the level of the rats with no stress (No stress) 2 h after releasing the stress load (Stress-2) in all groups. The enhancement of corticosterone level in the Stress-1 animals was large in the PSC and OLI groups, and the decline of this level in the Stress-2 animals was small in the OLI group when compared with the other groups. Although the concentrations of total cholesterol (T-CHOL) and triacylglycerol (TG) in the plasma were decreased by stress loading in all groups, these concentrations in the PSC and OLI groups were nearly always higher than in the other groups. The liver serine dehydratase (SDH) activity enhanced by stress was high in the OLI group and tended to be high in the PSC group when compared with the other groups. The contents of liver glycogen were reduced in the Stress-1 animals and extremely elevated in the Stress-2 animals of all groups, and particularly in the OLI group, the reduction in the Stress-1 animals was smaller and the enhancement in the Stress-2 animals was greater than in the other groups. These results suggest that feeding oleic acid to rats exposed to water-immersion restraint further accelerated liver glycogen synthesis through the rise in liver SDH activity due to increased corticosterone secretion when compared with the effect from linoleic and alpha-linolenic acids.

Animals↗

Ontogeny of pig discrete Peyer's patches: expression of surface antigens.

Leukocyte populations present in the discrete Peyer's patches (PP) of the pig were characterized from birth (Day 0) to day 35 after birth by immunohistochemistry and image analysis. Immediately after birth, cell membrane expression of CD2 and CD3, major histocompatibilty complex (MHC) class 11 (both SLA (swine leukocyte antigen) -DQ+ and SLA-DR+), CD21, 74-22-15 and surface immunoglobulin (sIg) were all demonstrable. Computer assisted morphometric techniques were used to confirm the significant expansion of these cell populations from birth onwards. The distribution of the cell types was not random but suggested a preferential retention of cells at specific sites. This implies a degree of organization of immunological cells within the discrete PP, enhancing the potential to mount immune responses in the most efficient manner.

Animals↗

Acute myocardial infarction showing total occlusion of right coronary artery and thrombus formation of left anterior descending artery.

A 33-year-old Japanese man had an attack of chest pain associated with ST-segment elevation in the inferolateral leads on his electrocardiogram. Emergency coronary angiography showed total obstruction in the mid right coronary artery (RCA) and a movable thrombus in the proximal left anterior descending artery (LAD). We performed emergency percutaneous transluminal coronary angioplasty (PTCA) for the RCA lesion. The operation was successful and we then conducted intracoronary thrombolysis (ICT) with tisokinase 6,400,000 IU for the LAD thrombus. Its size was reduced by ICT. He had an uneventful hospital course. After 1 month, repeat coronary angiography showed no significant stenosis in the RCA nor thrombus in the LAD. A coronary spasm provocation test was performed using acetylcholine. Coronary spasm in the LAD was induced by an intracoronary injection of 100 microg acetylcholine. In this case, we observed a unique condition suggesting simultaneous double coronary artery occlusion.

Adult↗

Analysis of a growth-promoting factor for Babesia caballi cultivation.

Serum-free media were examined to culture Babesia caballi. Daigo's T (DT) basal medium supplemented with Daigo's GF21 (GF21) or GIT medium, which already contains GF21, supported the parasite propagation at 37 C in a humidified atmosphere under 5% CO2 in air. Growth of B. caballi was dependent of the suitable concentration (10-20%) of GF21. Therefore, GF21 was suggested as the growth-promoting factor for B. caballi. However, GIT medium did not support the growth of parasites from cryopreserved stabilates, and serum supplementation was essential for the retrieval of parasites.

Animals↗