[Pyogenic vertebral osteomyelitis caused by Gemella haemolysans].
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Biomedical subjects
Publications and source records attributed to K Ito.
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In an experiment in which rats were allowed free access to food and water, the rats did not eat the diet containing a mushroom Pleurotus ostreatus even if they were emaciated. A P. ostreatus lectin (POL) was isolated from the mushroom as the food intake-suppression principle. In hemagglutination inhibition assays, Me-alphaGalNAc was the most potent inhibitor among the monosaccharides tested. Among all the sugars tested, 2'-fucosyllactose (Fucalpha1-->2Galbeta1-->4Glc) was the strongest inhibitor and its inhibitory potency was five times greater than that of Me-alphaGalNAc. POL exhibited a binding ability to bovine submaxillary mucin (BSM) and asialo-BSM and the other glycoproteins were inert to the binding. The food intake-suppressing activity of POL was dependent on the dose. The diet containing 0.1% POL caused a 50% decrease in the food intake of rats against the control.
The actin-dependent ATPase activity of Dictyostelium myosin II filaments is regulated by phosphorylation of the regulatory light chain. Four deletion mutant myosins which lack different parts of subfragment 2 (S2) showed phosphorylation-independent elevations in their activities. Phosphorylation-independent elevation in the activity was also achieved by a double point mutation to replace conserved Glu932 and Glu933 in S2 with Lys. These results suggested that inhibitory interactions involving the head and S2 are required for efficient regulation. Regulation of wild-type myosin was not affected by copolymerization with a S2 deletion mutant myosin in the same filaments. Furthermore, the activity linearly correlated with the fraction of phosphorylated molecules in wild-type filaments. These latter two results suggest that the inhibitory head-tail interactions are primarily intramolecular.
BACKGROUND: Several studies have shown that long-term right ventricular (RV) overload in animal models alters myocardial energy substrate metabolism. However, whether long-term RV volume overload alters this metabolism in the human is unclear. METHODS AND RESULTS: We performed positron emission tomography with [(18)F]fluorodeoxyglucose (FDG) and single-photon emission tomography (SPECT) with [(201)Tl]TlCl (Tl) and [(123)I]15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) in 11 patients with atrial septal defect (ASD) and 11 control subjects. In the FDG study, we calculated myocardial metabolic rate of glucose (MMR) in interventricular septum (IVS) and left ventricular (LV) free wall. MMR was significantly increased in IVS compared with LV free wall in the ASD patients (420+/-35 versus 333+/-32 mol x kg(-1) x min(-1); P<0.05) but not in the control group (347+/-27 versus 357+/-25 mol x kg(-1) x min(-1)). In both ASD and control groups, SPECT count was not significantly different between IVS and LV free wall in Tl (ASD, 160+/-11 versus 177+/-12; control, 141+/-12 versus 157+/-14 counts per 15 minutes) and BMIPP studies (ASD, 203+/-14 versus 212+/-18; control, 162+/-16 versus 176+/-16 counts per 15 minutes). MMR in the IVS/LV free wall ratio in the ASD group significantly correlated with indices related to RV volume overload. CONCLUSIONS: Given the assumption that long-term RV volume overload did not affect the lumped constant, the present study suggests that, unlike myocardial perfusion or fatty acid analogue uptake, myocardial glucose utilization in IVS relative to LV free wall is increased in relation to long-term RV volume overload in patients with ASD.
The biological effects of Amadori adducts that are early nonenzymatically glycated protein on vascular cells were poorly defined. We examined the effect of glycated serum albumin (GA) on the expression of monocyte chemoattractant protein-1(MCP-1) that is an important chemokine recruiting monocyte to blood vessel. GA increased MCP-1 mRNA expression with a peak after 3 h of stimulation. The induction of MCP-1 by GA was dose-dependent. The MCP-1 mRNA expression by GA was completely inhibited by PD98059 and genistein that inhibit mitogen activated protein (MAP) kinase kinase and tyrosine kinase, respectively. N-Acetylcysteine, a potent antioxidant, also suppressed the GA-induced MCP-1 expression. These results suggest that GA induces production of reactive oxygen species and activates tyrosine kinase and MAP kinase in VSMC. Activation of these signals results in MCP-1 expression. GA-induced MCP-1 expression may be one of the mechanisms by which the diabetic patients suffer from accelerated atherosclerosis.
T cell responses to self Ags and normal microbial flora are carefully regulated to prevent autoreactivity. Because IL-10-deficient mice develop colitis, and this response is triggered by luminal flora, we investigated whether IL-10 regulates the ability of microbial Ags to induce autoreactive T cells that could contribute to intestinal inflammation. T cells from wild-type mice were primed with staphylococcal enterotoxin B (SEB) in vitro, which induced an autoreactive proliferative response to syngeneic feeder cells. The cells were predominately CD3+ and CD4+. T cells from IL-10-deficient mice were constitutively autoreactive, and SEB priming enhanced this further. The autoreactive, proliferative response of T cells from wild-type mice was suppressed by IL-10 in the primary or secondary culture, and this effect was inhibited by neutralizing Abs to the IL-10R. To confirm that an autoreactive repertoire was expanded after SEB priming, we used CBA/J mice (Mls-1a) in which autoreactive T cells recognizing the endogenous viral superantigen are depleted (Vbeta6, 7, 8.1 TCR-bearing cells). However, SEB rescued these autoreactive T cell repertoires. Adding anti-MHC class II Ab blocked the autoreactive response. SEB-primed splenic or colonic T cells also induced apoptosis in syngeneic intestinal epithelial cells that was blocked significantly by IL-10. Thus, microbial Ags have the potential to abrogate self tolerance by stimulating autoreactive T cells that become cytolytic to target cells. IL-10 plays a protective role in maintaining self tolerance after microbial stimulation by preventing the activation of T cells that contribute to epithelial cell damage.
A natural tetrapeptide, acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) is a physiological negative regulator of hematopoiesis. The precursor of AcSDKP, thymocin beta 4, is expressed in many tissues including kidney. The present study examined the antiproliferative effect of AcSDKP in two renal cell lines, namely, renal interstitial fibloblasts cell line (NRK 49F) and renal proximal tubular epitherial cells (LLC-PK1). An addition of AcSDKP for 48 hours in theses cells resulted in a concentration-dependent attenuation in the proliferation rate (significant difference to non-treated cells was observed at 10(-9) to 10(-5) M AcSDKP) determined by a colorimetry of alamer blue oxidation. The cell cycle analysis of NRK 49F cells treated with AcSDKP showed that AcSDKP significantly reduced the ratio of S-phase to G2/M-phases. Thus, physiological concentrations of AcSDKP is capable of altering cell cycle to inhibit the proliferation of renal cells.
The two translational release factors of prokaryotes, RF1 and RF2, catalyse the termination of polypeptide synthesis at UAG/UAA and UGA/UAA stop codons, respectively. However, how these polypeptide release factors read both non-identical and identical stop codons is puzzling. Here we describe the basis of this recognition. Swaps of each of the conserved domains between RF1 and RF2 in an RF1-RF2 hybrid led to the identification of a domain that could switch recognition specificity. A genetic selection among clones encoding random variants of this domain showed that the tripeptides Pro-Ala-Thr and Ser-Pro-Phe determine release-factor specificity in vivo in RF1 and RF2, respectively. An in vitro release study of tripeptide variants indicated that the first and third amino acids independently discriminate the second and third purine bases, respectively. Analysis with stop codons containing base analogues indicated that the C2 amino group of purine may be the primary target of discrimination of G from A. These findings show that the discriminator tripeptide of bacterial release factors is functionally equivalent to that of the anticodon of transfer RNA, irrespective of the difference between protein and RNA.
The immunological mechanisms that regulate abortion are largely unknown. Here, we found that a distinct subset of lymphocytes, Valpha14 NKT cells expressing an invariant antigen receptor encoded by Valpha14/Jalpha281 and Vbeta7 segments, accumulated in the decidua during pregnancy and provoked abortion upon stimulation with alpha-galactosylceramide (alpha-GalCer), a specific ligand for Valpha14 NKT cells. The alpha-GalCer-mediated abortion was not observed in Valpha14 NKT-, IFN-gamma-, tumor necrosis factor alpha-, or perforin-knock-out mice and appeared to be due to the degeneration of embryonic trophoblasts mediated by the activated Valpha14 NKT cells whose perforin-dependent killing and production of IFN-gamma and tumor necrosis factor alpha were essential. The possible role of the decidual Valpha14 NKT cells in the pathogenesis of abortion is discussed.
It is demonstrated theoretically in the random phase approximation (RPA) that due to the intershell many-electron correlations the sigma(*) shape resonance in the photoionization of K shells of the N2 molecule appears not only in the 1sigma(g)-->varepsilonsigma(u) channel as it was believed earlier on the basis of single particle calculations, but in both 1sigma(g)-->varepsilonsigma(u) and 1sigma(u)-->varepsilonsigma(g) channels. As a confirmation of this phenomenon we show that the experimental angular distributions of photoelectrons ejected from fixed-in-space N2 molecules can be reproduced theoretically only after taking into account many-electron correlations.
Erythromycin (EM), and related 14-member macrolide antibiotics, has attracted attention for its effectiveness in airway diseases including diffuse panbronchiolitis and sinobronchial syndrome. However, its molecular mechanisms remain unknown. We evaluated the effects of EM on activation of several transcription factors, including nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) in human bronchial epithelial cell line BET-1A, which are known to regulate the expression of many proinflammatory cytokines and chemokines such as interleukin-8 (IL-8). BET-1A cells were cultured with hormonally defined Ham's F12 medium, and were stimulated by phorbol myristate acetate (PMA). EM suppressed mRNA expression as well as the release of IL-8 at therapeutic and noncytotoxic concentrations (% inhibition of IL-8 protein release: 42.2 +/- 5.5%, at 10(-6) M). Furthermore, electrophoretic mobility shift assays revealed that EM inhibited the activations of NF-kappaB and AP-1 induced by PMA in BET-1A cells. These data indicate that EM has inhibitory effects not only on the mRNA expression and release of IL-8, but also on the activation of transcription factors NF-kappaB and AP-1. Our findings support the concept that the recruitment of neutrophils in airway diseases may be regulated by NF-kappaB and AP-1.
BACKGROUND: It is well-known that the incidence of benign prostatic hyperplasia (BPH) increases with aging. The age-dependent changes in the ratio of serum sex steroid concentrations may play a role in BPH development. To clarify the relationship between the prostatic tissue concentrations of these steroids and age, we established a precise method of simultaneous quantitative analysis for prostatic sex steroids and used this method to investigate the tissue concentrations of three major sex steroids (testosterone, dihydrotestosterone, and estradiol) in the human prostate. METHODS: The methodology for the simultaneous quantitative analysis of prostatic sex steroids was established using castrated rat prostatic tissue, coupled with internal standards, for androgen-deprived medium, and the validation of the method was examined. Human prostatic tissues were collected during surgery and immediately frozen at -70 degrees C. Using our method, the steroidal fractions were extracted, purified, and quantified. The proportions of stroma, epithelium, and glandular lumen were measured on each histological specimen, using an image analyzer. RESULTS: The validation tests showed that our method of quantitative analysis was precise and sensitive enough for the quantification of testosterone, dihydrotestosterone, and estradiol in the prostate. In humans, the prostatic dihydrotestosterone concentration decreased with age, but the concentrations of testosterone and estradiol showed no relation with age. Therefore, the ratio of estradiol to dihydrotestosterone concentration (E2/DHT) in prostate increased with age. The E2/DHT ratio showed a significant positive correlation with the proportion of stroma. CONCLUSIONS: The age-dependent decrease in prostatic dihydrotestosterone and constant estradiol concentration lead to a relatively estrogen-dominant environment compared to that at younger ages. We assume that this relatively estrogen-dominant status induces stromal proliferation by some mechanism and leads to the development of BPH.
We examined the roles of fibroblast growth factor (FGF)-2 and FGF-8 in the migration of mesencephalic mouse neural crest cells. Our in vitro migration assay has shown that FGF-2 (basic FGF) and FGF-8 have chemotactic activity for these cells. Chemotaxis was inhibited by anti-FGF-2 and anti-FGF-8 neutralizing antibodies. In addition, anti-FGF-2 blocked neural crest cell migration in cranial organ cultures. This observation suggests that FGF-2 functions as a chemoattractant in migration of mesencephalic neural crest cells in vivo. In organ culture, the antagonist of FGF binding to a low-affinity fibroblast growth factor receptor (FGFR) heparan sulfate, inositolhexakisphosphate (InsP6), inhibited migration as well. Mesencephalic neural crest cells had high-affinity FGFRs, in particular FGFR-1 and FGFR-3. Thus, the chemotactic activities of FGF-2 can be mediated by the low-affinity FGFR alone or by a combination of low- and high-affinity FGFRs (FGFR-1, FGFR-3, or both). Moreover, differential localization of FGF-2 was found at the mesencephalic axial level of intact embryos during neural crest cell migration. FGF-2 protein expression was predominant in the target regions, in particular the mandibular mesenchyme, that are colonized by mesencephalic neural crest cells. This characteristic distribution supports the notion that FGF-2 acts as a chemoattractant in the mouse embryo that directs mesencephalic neural crest cell migration. Whereas FGF-8 showed chemotactic activity in vitro, neural crest cell dispersion was observed in explants that had been treated with anti-FGF-8 neutralizing antibodies. This result suggests that FGF-8 may not be a chemoattractant in vivo. However, the distribution of neural crest cells in explants treated with anti-FGF-8 differed from that in control explants or in intact embryos. Extreme FGF-2 distribution was observed in the mandibular arch and FGF-8 is expressed in the epithelium. FGF-8 may play a role in mesencephalic neural crest cell migration, and its role may be concerned with the differential localization of FGF-2. To establish this notion, we performed immunohistochemical examination of FGF-2 distribution in explants treated with FGF-8 and analysis of FGF-2 gene expression levels by reverse transcriptase-polymerase chain reaction by using RNA from explants. The data indicate that FGF-2 is distributed throughout the mesenchyme in FGF-8-treated explants and that expression of FGF-2 is promoted by FGF-8. Therefore, we conclude that the expression of FGF-8 in the mandibular arch epithelium is a prerequisite for the differential localization of FGF-2 and that the FGF-2 distribution pattern is essential for chemotaxis of mesencephalic neural crest cell migration.
The purpose of this study was to determine whether the finding of an enlarged hilar periportal space is a sign for early cirrhosis at magnetic resonance (MR) imaging. Forty-one pathologically proved cirrhotic patients in the early stage of disease who did not show conventional imaging findings of cirrhosis (early cirrhosis group) and 47 patients without history of chronic liver diseases (control group) were included in this study. MR images were qualitatively and quantitatively evaluated for the presence of enlargement of the periportal space. Enlargement of the periportal space was seen in 98% of patients in the early cirrhosis group, while this finding was seen in 11% of patients in the control group (P < 0.0001). The mean value of the hilar periportal fat thickness was significantly greater (P < 0.0001) in the early cirrhosis group (15.5 +/- 6.2 mm) than in the control group (5.3 +/- 3.1 mm). The sensitivity, specificity, accuracy, and positive predictive value of this finding for the MR diagnosis of cirrhosis with a cutoff value of 10 mm were 93%, 92%, 92%, and 91%, respectively. Enlargement of the hilar periportal space is a helpful sign at MR imaging in the discrimination between normal and early cirrhotic livers.
Doxorubicin produces clinically useful responses in a variety of human cancers. However, the toxicity of doxorubicin has limited its usefulness. This side effect is mainly due to the doxorubicin-mediated free radical formation. Administration of doxorubicin (10 mg/kg body weight) to rats intravenously induces heme oxygenase-1 (HO-1) in the liver. The levels of HO-1 protein were first detected at 6 hours and peaked at about 18 to 24 hours after the injection. It is known that HO-1 plays a protective role against the oxidative injury. Therefore, we have examined the protective effect of doxorubicin preconditioning against the hepatic ischemia-reperfusion injury. Partial hepatic ischemia was produced in the left and medium lobes for 45 minutes followed by 120 minutes reperfusion. When low doses of doxorubicin (1 mg/kg body weight) was intravenously administered to rats 2 days before the ischemia, the serum alanine transaminase (ALT) levels in the preconditioning rat were clearly improved compared with those in the rat without preconditioning. Under this situation, zinc-protoporphyrin IX, a specific inhibitor of HO-1, was injected subcutaneously to rats at 3 and 16 hours before the ischemia, the ALT levels were not improved by doxorubicin preconditioning. Histopathologic examination also supported these results. Although the HO-1 protein level was fairly low 2 days after the doxorubicin administration, significant amounts of HO-1 protein were detected. Our results indicated that the induction of HO-1 played a protective role against hepatic ischemia-reperfusion injury and that doxorubicin preconditioning is more clinically useful than other preconditioning methods.
Choroidal metastasis from recurrent ovarian cancer is extremely rare. To our knowledge, this report is the first such case of endometrioid adenocarcinoma. A 30-year-old pregnant woman presented to an ophthalmologist in January 1999 because of a rapid visual deterioration. Ophthalmologic evaluation revealed a metastatic choroidal tumor from ovarian cancer which had been diagnosed 10 years ago. After cesarean section, multiple metastases were found including the choroid, scalp, bone, and lung, and she received four courses of single agent carboplatin chemotherapy. She died of disease in July 1999. This case highlights the need to investigate the etiology of visual complaints in patients with a history of ovarian cancer even in the early stage.
The aim of this study was to define the mean regional 6-[(18)F]fluoro-l-dopa (FDOPA) uptake rate constant (K(i)) values in the striatal and extrastriatal regions of the brain of normal subjects using magnetic resonance imaging (MRI)-aided spatial normalization of the FDOPA K(i) image and using automatic region of interest (ROI) analysis. Dynamic three-dimensional FDOPA positron emission tomography (PET) and three-dimensional magnetic resonance (MR) images were acquired in 13 aged normal subjects. The FDOPA add image and the K(i) image of each subject were transformed into standard stereotactic space with the aid of individual coregistered MR image. The mean regional K(i) values of the striatal and extrastriatal regions before normalization were compared with the respective values after normalization. Then automatic ROI analysis was performed on the MRI-aided spatially normalized K(i) images of the 13 normal subjects. The K(i) values on original images and those on spatially normalized images were in good agreement, indicating that the spatial normalization technique did not change the regional K(i) values appreciably. Automatic ROI analysis of the spatially normalized FDOPA K(i) images of the normal subjects, showed high K(i) values in ventral and dorsal regions of the midbrain, amygdala, hippocampus, and medial prefrontal cortex, in addition to caudate nucleus and putamen, which correspond to the dopaminergic projections in the brain. Spatial normalization technique helped to establish a database of FDOPA K(i) images of normal subjects and high K(i) values were observed widely besides striatal regions corresponding to the dopaminergic projections in the brain.
A 55-yr-old man underwent surgery. Soon after the procedure was finished, the patient complained of chest pain, and the electrocardiogram showed increase in the ST-segment in some leads. Emergency angiography showed normal coronary arteries, but there was asynergy in the left ventricle, and delayed filling of contrast medium was observed in the LCA. An intracoronary infusion of isosorbide dinitrate did not improve the delayed filling of contrast medium or ST segment increase in the electrocardiogram. Soon after nicorandil was injected into the LCA, the patient's symptoms, electrocardiogram, and delayed filling of contrast medium dramatically improved. On the second day, initial imaging by 123I-BMIPP myocardial SPECT showed a moderate increase in tracer uptake in the apico-anteroseptal region and a moderate decrease in tracer uptake in the lateral region, in which the first left ventriculography showed akinesis, and delayed imaging revealed a moderate increase in tracer uptake in the apical region and a high washout of 123I-BMIPP in the anteroseptal and lateral regions. On the sixth day, initial imaging by 123I-BMIPP myocardial SPECT showed a moderate decrease in tracer uptake in the apical and lateral regions and a mild decrease in tracer uptake in the anteroseptal region, and delayed imaging revealed a moderate increase in tracer uptake in the apical region and a high washout of 123I-BMIPP in the anteroseptal and lateral regions. By the 30th day, 123I-BMIPP myocardial SPECT had normalized. We consider that these dynamic changes in 123I-BMIPP myocardial SPECT imaging may reflect metabolic changes in fatty acids in the ischemic state, the size of the triacylglycerol pool, and the degree of turnover in the triacylglycerol pool.