214 research outputs found
Orientifold Planes, Type I Wilson Lines and Non-BPS D-branes
There is a longstanding puzzle concerned with the existence of Op~-planes
with p>=6, which are orientifold p-planes of negative charge with stuck
Dp-branes. We study the consistency of configurations with various orientifold
planes and propose a resolution to this puzzle. It is argued that O6~-planes
are possible in massive IIA theory with odd cosmological constant, while
O7~-planes and O8~-planes are not allowed. Various relations between
orientifold planes and non-BPS D-branes are also addressed.Comment: 30 pages, 5 figures, added footnot
Histo- and Immunopathological Studies on the Allergic Pneumonitis Induced in Sensitized Rabbits by Intravenous Provocative Injection of Ferritin Purified from Horse Spleen.
Histo- and immunopathological studies on the allergic pneumonitis induced in sensitized rabbits by intravenous provocative injection of ferritin purified from horse spleen were presented. The experimental results here obtained have been described and pathogenesis of the pneumonitis has been considered. The fundamental pathologic processes underlying the pneumonitis presented here are said to be characterized by a transformation of alveolar capillaries and intercapillary connective tissue into reticular or enmeshed structure simulating reticular tissue of antibody-forming organs which is induced by localization and fixation of immune complexes in the alveolar walls through the phagocytic activity of cellular components in this structure
Experimental H-type bovine spongiform encephalopathy characterized by plaques and glial- and stellate-type prion protein deposits
Atypical bovine spongiform encephalopathy (BSE) has recently been identified in Europe, North America, and Japan. It is classified as H-type and L-type BSE according to the molecular mass of the disease-associated prion protein (PrPSc). To investigate the topographical distribution and deposition patterns of immunolabeled PrPSc, H-type BSE isolate was inoculated intracerebrally into cattle. H-type BSE was successfully transmitted to 3 calves, with incubation periods between 500 and 600 days. Moderate to severe spongiform changes were detected in the cerebral and cerebellar cortices, basal ganglia, thalamus, and brainstem. H-type BSE was characterized by the presence of PrP-immunopositive amyloid plaques in the white matter of the cerebrum, basal ganglia, and thalamus. Moreover, intraglial-type immunolabeled PrPSc was prominent throughout the brain. Stellate-type immunolabeled PrPSc was conspicuous in the gray matter of the cerebral cortex, basal ganglia, and thalamus, but not in the brainstem. In addition, PrPSc accumulation was detected in the peripheral nervous tissues, such as trigeminal ganglia, dorsal root ganglia, optic nerve, retina, and neurohypophysis. Cattle are susceptible to H-type BSE with a shorter incubation period, showing distinct and distinguishable phenotypes of PrPSc accumulation
Intraspecies Prion Transmission Results in Selection of Sheep Scrapie Strains
Background: Sheep scrapie is caused by multiple prion strains, which have been classified on the basis of their biological characteristics in inbred mice. The heterogeneity of natural scrapie prions in individual sheep and in sheep flocks has not been clearly defined. Methodology/Principal Findings: In this study, we intravenously injected 2 sheep (Suffolk and Corriedale) with material from a natural case of sheep scrapie (Suffolk breed). These 3 sheep had identical prion protein (PrP) genotypes. The protease-resistant core of PrP (PrPres) in the experimental Suffolk sheep was similar to that in the original Suffolk sheep. In contrast, PrPres in the Corriedale sheep differed from the original PrPres but resembled the unusual scrapie isolate, CH1641. This unusual PrPres was not detected in the original sheep. The PrPres distributions in the brain and peripheral tissues differed between the 2 breeds of challenged sheep. A transmission study in wild-type and TgBoPrP mice, which overexpressing bovine PrP, led to the selection of different prion strains. The pathological features of prion diseases are thought to depend on the dominantly propagated strain. Conclusions/Significance: Our results indicate that prion strain selection occurs after both inter- and intraspecie
Sulfated Dextrans Enhance In Vitro Amplification of Bovine Spongiform Encephalopathy PrPSc and Enable Ultrasensitive Detection of Bovine PrPSc
Prions, infectious agents associated with prion diseases such as Creutzfeldt-Jakob disease in humans, bovine spongiform encephalopathy (BSE) in cattle, and scrapie in sheep and goats, are primarily comprised of PrP(Sc), a protease-resistant misfolded isoform of the cellular prion protein PrP(C). Protein misfolding cyclic amplification (PMCA) is a highly sensitive technique used to detect minute amounts of scrapie PrP(Sc). However, the current PMCA technique has been unsuccessful in achieving good amplification in cattle. The detailed distribution of PrP(Sc) in BSE-affected cattle therefore remains unknown.We report here that PrP(Sc) derived from BSE-affected cattle can be amplified ultra-efficiently by PMCA in the presence of sulfated dextran compounds. This method is capable of amplifying very small amounts of PrP(Sc) from the saliva, palatine tonsils, lymph nodes, ileocecal region, and muscular tissues of BSE-affected cattle. Individual differences in the distribution of PrP(Sc) in spleen and cerebrospinal fluid samples were observed in terminal-stage animals. However, the presence of PrP(Sc) in blood was not substantiated in the BSE-affected cattle examined.The distribution of PrP(Sc) is not restricted to the nervous system and can spread to peripheral tissues in the terminal disease stage. The finding that PrP(Sc) could be amplified in the saliva of an asymptomatic animal suggests a potential usefulness of this technique for BSE diagnosis. This highly sensitive method also has other practical applications, including safety evaluation or safety assurance of products and byproducts manufactured from bovine source materials
Expanded Strings in the Background of NS5-branes via a M2-brane, a D2-brane and D0-branes
Classical configurations of a M2-brane, a D2-brane and D0-branes are
investigated in the background of an infinite array of M5-branes or NS5-branes.
On the M2-brane, we discuss three kinds of configurations, such as a sphere, a
cylinder and a torus-like one. These are stabilized by virtue of the background
fluxes of M5-branes. The torus-like M2-brane configuration has winding and
momentum numbers of 11th direction, and in terms of the type IIA superstring
theory, this corresponds to a torus-like D2-brane with electric and magnetic
fluxes on it. We also reproduce the same configuration from a non-abelian
Born-Infeld action for D0-branes. It will be a construction of closed strings
from D0-branes. An electric flux quantization condition on the D2-brane is also
discussed in terms of D0-branes.Comment: 33 pages, 6 figures, references and footnote added, confusing
expressions and introduction are improved, version to appear in JHE
Paradoxical response to disseminated non-tuberculosis mycobacteriosis treatment in a patient receiving tumor necrosis factor-α inhibitor: a case report
Background: Biological agents such as tumor necrosis factor-α inhibitors are known to cause mycobacterium infections. Here, we report a disseminated non-tuberculosis case caused by TNF-α inhibitor therapy and a probable paradoxical response to antimycobacterial therapy.Case presentation: A 68-year-old man with relapsing polychondritis was refractory to glucocorticoid therapy; adalimumab was therefore administered in combination with oral glucocorticoids. Treatment with 40 mg of adalimumab led to rapid improvement of his clinical manifestations. The administration of tacrolimus (1 mg) was started as the dosage of oral glucocorticoids was tapered. However, the patient developed an intermittent high fever and productive cough 15 months after starting adalimumab treatment. A chest computed tomography scan revealed new granular shadows and multiple nodules in both lung fields with mediastinal lymphadenopathy, and Mycobacterium intracellulare was isolated from 2 sputum samples; based on these findings, the patient was diagnosed with non-tuberculosis mycobacteriosis. Tacrolimus treatment was discontinued and oral clarithromycin (800 mg/day), rifampicin (450 mg/day), and ethambutol (750 mg/day) treatment was initiated. However, his condition continued to deteriorate despite 4 months of treatment; moreover, paravertebral and subcutaneous abscesses developed and increased the size of the mediastinal lymphadenopathy. Biopsy of the mediastinal lymphadenopathy and a subcutaneous abscess of the right posterior thigh indicated the presence of Mycobacterium avium complex (MAC), and the diagnosis of disseminated non-tuberculosis mycobacteriosis was confirmed. Despite 9 months of antimycobacterial therapy, the mediastinal lymphadenopathy and paravertebral and subcutaneous abscesses had enlarged and additional subcutaneous abscesses had developed, although microscopic examinations and cultures of sputum and subcutaneous abscess samples yielded negative results. We considered this a paradoxical reaction similar to other reports in tuberculosis patients who had discontinued biological agent treatments, and increased the dose of oral glucocorticoids. The patient\u27s symptoms gradually improved with this increased dose and his lymph nodes and abscesses began to decrease in size.Conclusions: Clinicians should consider the possibility of a paradoxical response when the clinical manifestations of non-tuberculosis mycobacteriosis worsen in spite of antimycobacterial therapy or after discontinuation of tumor necrosis factor-α inhibitors. However, additional evidence is needed to verify our findings and to determine the optimal management strategies for such cases
Comprehensive Prospective Analysis of the Factors Contributing to Aspiration Pneumonia Following Endoscopic Submucosal Dissection in Patients with Early Gastric Neoplasms
Endoscopic submucosal dissection (ESD) has become the first-line treatment for early gastric neoplasms; however, a subset of patients treated by this method develop aspiration pneumonia. We conducted a comprehensive prospective analysis of the factors contributing to post-ESD aspiration pneumonia in early gastric neoplasms in this study, with special focus on whether pre-treatment oral care can prevent aspiration pneumonia. Sixty-one patients who underwent ESD for gastric neoplasms were randomly assigned to the oral care or control groups. ESD was performed under deep sedation. Of 60 patients whose data were available for analysis, 5 (8.3%) experienced pneumonia confirmed either by chest radiography or computed tomography. Although no difference in the rate of pneumonia was found between the control and oral care groups, the post-oral care bacteria count was significantly higher in the saliva of patients who developed pneumonia compared to those without pneumonia. In addition, the presence of vascular brain diseases and the dose of meperidine were also significantly associated with the occurrence of pneumonia. These results suggest that the number of oral bacteria as well as pre-existing vascular brain diseases and high-dose narcotics can affect the incidence of post-ESD pneumonia
Accumulation of L-type Bovine Prions in Peripheral Nerve Tissues
We recently reported the intraspecies transmission of L-type atypical bovine spongiform encephalopathy (BSE). To clarify the peripheral pathogenesis of L-type BSE, we studied prion distribution in nerve and lymphoid tissues obtained from experimentally challenged cattle. As with classical BSE prions, L-type BSE prions accumulated in central and peripheral nerve tissues
ERG3-encoding sterol C5,6-DESATURASE in Candida albicans Is required for virulence in an enterically infected invasive candidiasis mouse model
Gastrointestinal colonization by Candida species is considered the main source of candidemia. The ERG3 gene in Candida albicans encodes a sterol C5,6-desaturase, which is essential for ergosterol biosynthesis. Although ERG3 inactivation shows reduced virulence in mouse models of disseminated candidiasis, the role of ERG3 in intestinal infections is unknown. Here, we infected mice with the C. albicans strains CAE3DU3 and CAF2-1, containing mutant and wild-type ERG3, respectively, and studied gut infection and colonization by these strains. We found that the CAE3DU3 strain showed reduced colonization, pathogenesis, damage to gut mucosa, and chemokine production in the mouse model of invasive candidiasis. Additionally, mice inoculated with CAE3DU3 showed lower mortality than mice inoculated with CAF2-1 (p < 0.0001). Chemokines were less induced in the gut inoculated with CAE3DU3 than in the gut inoculated with CAF2-1. Histopathologically, ]although the wild-type gene was associated with a higher pathogenicity and invasion of the gut mucosa and liver tissues causing remarkable tissue necrosis, the erg3/erg3 mutant was associated with a higher accumulation of cells and lower damage to surrounding tissues than wild-type ERG3. These results establish that the ergosterol biosynthetic pathway may be associated with C. albicans gut colonization and subsequent dissemination
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