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Query: UMLS:C0153470 (Spleen)
 4,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Single-strain infections and coinfections are frequently used to assess roles of virulence factors in infected tissues. After oral inoculation of mice, Yersinia pseudotuberculosis yopE and yopH mutants colonize the intestines and Peyer's patches in single-strain infections but fail to persist in competition with wild-type Y. pseudotuberculosis, indicating that these two infection models provide different insights into the roles of Yops. To determine how wild-type Y. pseudotuberculosis hinders yop mutant survival, yop mutant colonization and host responses were investigated in several different infection models that isolated specific features of wild-type Y. pseudotuberculosis infection. Infection with wild-type Y. pseudotuberculosis caused significantly more inflammation than yop mutants. Results from coinfections of gamma interferon (IFN-gamma)-/- mice revealed that IFN-gamma-regulated defenses target these mutants, suggesting that YopE and YopH protect Y. pseudotuberculosis from these defenses in BALB/c mice. We developed an oral-intraperitoneal infection model to evaluate the effects of spleen and liver colonization by Y. pseudotuberculosis on yop mutants in the intestines. Spleen and liver infection increased inflammation and decreased yop mutant survival in the intestines, indicating that infection of these organs has consequences in intestinal tissues. Finally, competition infections with Y. pseudotuberculosis mutants with various abilities to induce inflammation demonstrated that survival of the yopE, but not the yopH, mutant was consistently decreased in inflamed tissues. In summary, infection with Y. pseudotuberculosis in intestinal and systemic sites induces intestinal inflammation, which decreases yop mutant survival. Thus, competition studies with wild-type yersiniae reveal critical roles of Yops in combating host responses to a normal virulent infection.
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PMID:The proinflammatory response induced by wild-type Yersinia pseudotuberculosis infection inhibits survival of yop mutants in the gastrointestinal tract and Peyer's patches. 1649 22

When blood plasma proteins are depleted by bleeding, with return of washed red cells (plasmapheresis), it is possible to bring the dog to a steady state of low plasma protein in the circulation and a uniform plasma protein production on a basal diet. These dogs become test subjects by which the potency of various diet factors for plasma protein regeneration can be measured. Plant and grain proteins are quite well utilized to form new plasma protein in these test dogs but soy bean meal probably should be rated at the head of this list. It is utilized with unexpected promptness and favors the production of albumin in contrast to other plant proteins which distinctly favor globulin production. Long plasmapheresis periods on basal rations rich in grain proteins lower the resistance of these animals to infection. Spleen, brain, and stomach when fed with the basal diet in these test dogs show less favorable potency ratios-10.2, 11.8, and 13.6 respectively. This means the grams of tissue protein which must be fed to produce 1 gm. of new plasma protein. Fasting periods indicate that the dog can contribute only 4 to 6 gm. of plasma protein each week-an insignificant contribution presumably derived from the host's tissue proteins. Infection and intoxication disturb the plasma protein production of these standardized dogs and may reduce the output of plasma proteins to very low levels in spite of considerable food intake. There may be a very sharp drop in the plasma protein level during the first day of intoxication (Dog 33-324). Some of these observations may be of value in a study of clinical conditions associated with hypoproteinemia.
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PMID:BLOOD PLASMA PROTEIN REGENERATION CONTROLLED BY DIET : EFFECTS OF PLANT PROTEINS COMPARED WITH ANIMAL PROTEINS THE INFLUENCE OF FASTING AND INFECTION. 1987 Apr 72

The spread of dengue (DEN) worldwide combined with an increased severity of the DEN-associated clinical outcomes have made this mosquito-borne virus of great global public health importance. Progress in understanding DEN pathogenesis and in developing effective treatments has been hampered by the lack of a suitable small animal model. Most of the DEN clinical isolates and cell culture-passaged DEN virus strains reported so far require either host adaptation, inoculation with a high dose and/or intravenous administration to elicit a virulent phenotype in mice which results, at best, in a productive infection with no, few, or irrelevant disease manifestations, and with mice dying within few days at the peak of viremia. Here we describe a non-mouse-adapted DEN2 virus strain (D2Y98P) that is highly infectious in AG129 mice (lacking interferon-alpha/beta and -gamma receptors) upon intraperitoneal administration. Infection with a high dose of D2Y98P induced cytokine storm, massive organ damage, and severe vascular leakage, leading to haemorrhage and rapid death of the animals at the peak of viremia. In contrast, very interestingly and uniquely, infection with a low dose of D2Y98P led to asymptomatic viral dissemination and replication in relevant organs, followed by non-paralytic death of the animals few days after virus clearance, similar to the disease kinetic in humans. Spleen damage, liver dysfunction and increased vascular permeability, but no haemorrhage, were observed in moribund animals, suggesting intact vascular integrity, a cardinal feature in DEN shock syndrome. Infection with D2Y98P thus offers the opportunity to further decipher some of the aspects of dengue pathogenesis and provides a new platform for drug and vaccine testing.
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PMID:A non mouse-adapted dengue virus strain as a new model of severe dengue infection in AG129 mice. 2043 20

Infection of mice with Salmonella enterica serovar Typhimurium (Salmonella) causes systemic inflammatory disease and enlargement of the spleen (splenomegaly). Splenomegaly has been attributed to a general increase in the numbers of phagocytes, lymphocytes, as well as to the expansion of immature CD71+Ter119+ reticulocytes. The spleen is important for recycling senescent red blood cells (RBCs) and for the capture and eradication of blood-borne pathogens. Conservation of splenic tissue architecture, comprised of the white pulp (WP), marginal zone (MZ), and red pulp (RP) is essential for initiation of adaptive immune responses to captured pathogens. Using flow cytometry and four color immunofluorescence microscopy (IFM), we show that Salmonella-induced splenomegaly is characterized by drastic alterations of the splenic tissue architecture and cell population proportions, as well as in situ cell distributions. A major cause of splenomegaly appears to be the significant increase in immature RBC precursors and F4/80+ macrophages that are important for recycling of heme-associated iron. In contrast, the proportions of B220+, CD4+ and CD8+ lymphocytes, as well as MZ MOMA+ macrophages decrease significantly as infection progresses. Spleen tissue sections show visible tears and significantly altered tissue architecture with F4/80+ macrophages and RBCs expanding beyond the RP and taking over most of the spleen tissue. Additionally, F4/80+ macrophages actively phagocytose not only RBCs, but also lymphocytes, indicating that they may contribute to declining lymphocyte proportions during Salmonella infection. Understanding how these alterations of spleen microarchitecture impact the generation of adaptive immune responses to Salmonella has implications for understanding Salmonella pathogenesis and for the design of more effective Salmonella-based vaccines.
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PMID:Infection with Salmonella enterica Serovar Typhimurium Leads to Increased Proportions of F4/80+ Red Pulp Macrophages and Decreased Proportions of B and T Lymphocytes in the Spleen. 2606 6

Infection by blood flukes Hapalotrema mistroides and Neospirorchis sp. (Digenea: Spirorchiidae) has been recently reported in Caretta caretta (Linnaeus, 1758) in the Mediterranean Sea. Observations of post mortem lesions are generally used to assess disease severity, and few attempts have been made to standardize the evaluation of the parasitic burden from tissue egg counts. Faeces and spleen homogenates of 105 loggerheads from the northwestern Adriatic Sea were submitted to a sedimentation-flotation technique for the research of spirorchiid eggs; molecular techniques were used for unequivocal identification. Egg quantification for positive faeces and spleen samples was achieved using a modified McMaster method. Spleen samples were also submitted to quantification through the only method cited in the literature for similar purposes, which involves preventive chemical digestion. Correlations between splenic counts obtained from the two different methods and between faecal and splenic egg burdens were calculated using Spearman's rho test. Concordance between studies on eggs in faeces and spleen tissue was also calculated. Eggs of H. mistroides and Neogen-11 were found in spleen and faecal samples. Strong correlations were found between splenic egg burdens calculated from the two methods for H. mistroides, demonstrating that the modified McMaster method can be used for quantification. A multiplying factor must be used before drawing comparisons, as egg burdens are higher in value when measured after chemical digestion. High concordance was obtained from a qualitative examination of faeces and spleen tissue of H. mistroides, showing that copromicroscopic examination can be used for in vivo diagnosis. As weak correlations were found between faecal and splenic egg counts, faecal burden cannot be regarded as indicative of disease severity. For Neogen-11, low concordance was found between faeces and spleen tissue, likely reflecting lower levels of egg embolization in organs.
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PMID:Qualitative and quantitative methods for estimating Spirorchiidiasis burden in sea turtles. 3041 58

The red fox (Vulpes vulpes) is known to be a reservoir host of various vector-borne protozoan parasites. Yet, the impact of these parasitic infections on the health status of the red fox is unknown. In this study, we compared the prevalence of haemoprotozoa in juvenile and adult foxes from four regions in Poland. The abundance of questing adult Dermacentor reticulatus ticks was shown to differ between regions and include a tick-endemic and non-endemic region, as well as two zones in which D. reticulatus recently expanded: an eastern and a western zone. Spleen and kidney enlargement indices were compared between infected, co-infected and non-infected foxes to evaluate pathogenic output of parasitic infections. Blood samples were collected from 383 necropsied red foxes and 25 live-trapped red fox cubs. The weights of spleens, kidneys and bodies were recorded for each necropsied individual. Blood and spleen DNA samples were screened by PCR to detect 18S rRNA and cox1 gene fragments of Babesia spp., and 18S rRNA of Hepatozoon spp. Prevalence of infection and mean organ weight indices were compared in relation to fox age and sex, origin (zone) and infection status. Hepatozoon canis (174/381; 45.7%) and Babesia vulpes (117/381; 30.7%) were the dominant pathogens infecting adult foxes. Babesia canis DNA was detected in 9 (2.4%) individuals. Two fox cubs from Western Poland were infected with B. vulpes (2/14; 14%), while H. canis infection (16/25; 59%) was detected in cubs from all three regions where trapping was carried out. Infection with B. vulpes was associated with significantly higher weights of spleens and kidneys. Spleen weight/ body weight and mean kidney weight/ body weight indices were shown as relevant in evaluating changes occurring during infection with B. vulpes. Babesia and Hepatozoon spp. infections differed in red foxes from D. reticulatus-endemic, non-endemic and newly inhabited areas. The prevalence of B. canis in foxes from four regions of Poland reflects the prevalence recorded in questing adult D. reticulatus collected in these areas. This finding suggests a contribution of red foxes to the establishment of new foci of B. canis-infected D. reticulatus ticks in areas recently invaded by this tick species. Spleen and kidney enlargement was identified in foxes infected with B. vulpes, particularly in individuals co-infected with B. vulpes and H. canis.
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PMID:The red fox (Vulpes vulpes), a possible reservoir of Babesia vulpes, B. canis and Hepatozoon canis and its association with the tick Dermacentor reticulatus occurrence. 3300 8


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