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Repeated Infections (repeated + infections)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

The impact of successive infections on the lung microenvironment

IMMUNOLOGY, Issue 4 2007
Arnaud Didierlaurent
Summary The effect of infection history on the immune response is ignored in most models of infectious disease and in preclinical vaccination studies. No one, however, is naïve and repeated microbial exposure, in particular during childhood, shapes the immune system to respond more efficiently later in life. Concurrent or sequential infections influence the immune response to secondary unrelated pathogens. The involvement of cross-reactive acquired immunity, in particular T-cell responses, is extensively documented. In this review, we discuss the impact of successive infections on the infected tissue itself, with a particular focus on the innate response of the respiratory tract, including a persistent alteration of (1) epithelial or macrophage expression of Toll-like receptors or adherence molecules used by subsequent bacteria to invade the host, (2) the responsiveness of macrophages and neutrophils and (3) the local cytokine milieu that affects the activation of local antigen-presenting cells and hence adaptive immunity to the next infection. We emphasize that such alterations not only occur during coinfection, but are maintained long after the initial pathogen is cleared. As innate responses are crucial to the fight against local pathogens but are also involved in the maintenance of the homeostasis of mucosal tissues, dysregulation of these responses by repeated infections is likely to have a major impact on the outcome of infectious or allergic disease. [source]

Cell resilience in species life spans: a link to inflammation?

AGING CELL, Issue 4 2010
Caleb E. Finch
Summary Species differences in life span have been attributed to cellular survival during various stressors, designated here as ,cell resilience'. In primary fibroblast cultures, cell resilience during exposure to free radicals, hypoglycemia, hyperthermia, and various toxins has shown generally consistent correlations with the species characteristic life spans of birds and mammals. However, the mechanistic links of cell resilience in fibroblast cultures to different species life spans are poorly understood. We propose that certain experimental stressors are relevant to somatic damage in vivo during inflammatory responses of innate immunity, particularly, resistance to reactive oxygen species (ROS), low glucose, and hyperthermia. According to this hypothesis, somatic cell resilience determines species differences in longevity during repeated infections and traumatic injuries in the natural environment. Infections and injury expose local fibroblasts and other cells to ROS generated by macrophages and to local temperature elevations. Systemically, acute phase immune reactions cause hypoglycemia and hyperthermia. We propose that cell resilience to somatic stressors incurred in inflammation is important in the evolution of longevity and that longer-lived species are specifically more resistant to immune-related stressors. This hypothesis further specifies Kirkwood's disposable soma theory. We suggest expanding the battery of stressors and markers used for comparative studies to additional cell types and additional parameters relevant to host defense and to their ecological specificities. [source]

Interactions between gnathiid isopods, cleaner fish and other fishes on Lizard Island, Great Barrier Reef

JOURNAL OF FISH BIOLOGY, Issue 9 2008
A. S. Grutter
The rate of emergence of micropredatory gnathiid isopods from the benthos, the proportion of emerging gnathiids potentially eaten by Labroides dimidiatus, and the volume of blood that gnathiids potentially remove from fishes (using gnathiid gut volume) were determined. The abundance (mean ±s.e.) of emerging gnathiids was 41·7 ± 6·9 m,2 day,1 and 4552 ± 2632 reef,1 day,1 (reefs 91,125 m2). The abundance of emerging gnathiids per fish on the reef was 4·9 ± 0·8 day,1; but excluding the rarely infested pomacentrid fishes, it was 20·9 ± 3·8 day,1. The abundance of emerging gnathiids per patch reef was 66 ± 17% of the number of gnathiids that all adult L. dimidiatus per reef eat daily while engaged in cleaning behaviour. If all infesting gnathiids subsequently fed on fish blood, their total gut volume per reef area would be 17·4 ± 5·6 mm3 m,2 day,1; and per fish on the reefs, it would be 2·3 ± 0·5 mm,3 fish,1 day,1 and 10·3 ± 3·1 mm3 fish,1 day,1 (excluding pomacentrids). The total gut volume of gnathiids infesting caged (137 mm standard length, LS) and removed from wild (100,150 mm LS) Hemigymnus melapterus by L. dimidiatus was 26·4 ± 24·6 mm3 day,1 and 53·0 ± 9·6 mm3 day,1, respectively. Using H. melapterus (137 mm LS, 83 g) as a model, gnathiids had the potential to remove, 0·07, 0·32, 0·82 and 1·63% of the total blood volume per day of each fish, excluding pomacentrids, caged H. melapterus and wild H. melapterus, respectively. In contrast, emerging gnathiids had the potential of removing 155% of the total blood volume of Acanthochromis polyacanthus (10·7 mm LS, 0·038 g) juveniles. That L. dimidiatus eat more gnathiids per reef daily than were sampled with emergence traps suggests that cleaner fishes are an important source of mortality for gnathiids. Although the proportion of the total blood volume of fishes potentially removed by blood-feeding gnathiids on a daily basis appeared to be low for fishes weighing 83 g, the cumulative effects of repeated infections on the health of such fish remains unknown; attacks on small juvenile fishes, may result in possibly lethal levels of blood loss. [source]

Persons, Places, and Times: The Meanings of Repetition in an STD Clinic

MEDICAL ANTHROPOLOGY QUARTERLY, Issue 2 2007
Lori Leonard
In this article we work the tensions between the way clinical medicine and public health necessarily construct the problem of "repetition" in the context of a sexually transmitted disease (STD) clinic and the ways patients narrate their illness experiences. This tension,between clinical and epidemiological exigencies and the messiness of lived experience,is a recurring theme of work conducted at the intersections of epidemiology, anthropology, and clinical medicine. Clinically, repeated infections are a threat to the individual body and to "normal" biological processes like reproduction. From a public health perspective, "repeaters" are imagined to be part of a "core group" that keeps infections in circulation, endangering the social body. Yet patients' accounts are anchored in particular social histories, and their experiences rely on different time scales than those implicated in either of these types of readings. Extended analyses are provided of two such accounts: one in which repetition can be "read" as part of a performance of recovery, and one in which repetition is bound up in the effort to avoid becoming the involuntary subject of institutionally administered intervention. We argue the need to open up the category of repeaters to include the social and draw on work by Cheryl Mattingly to suggest that one way to do this in the context of the STD clinic might be to adopt forms of therapeutic practice that make use of interpretive, in addition to technical, skills. [source]

Differential immunoglobulin E and cytokine responses in BALB/c and C57Bl/6 mice during repeated infections with blood-stage Plasmodium chabaudi malaria

PARASITE IMMUNOLOGY, Issue 4 2000
Helena Helmby
Repeated blood-stage Plasmodium chabaudi chabaudi AS challenge infections in BALB/c and C57Bl/6 mice result in increased serum immunoglobulin (Ig) E levels and splenic cytokine production. The genetic background of the host influences both the cytokine response as well as the development of IgE antibodies. BALB/c mice showed high interleukin (IL)-4 secretion from splenocytes after in-vitro stimulation with malaria antigen after repeated P. chabaudi challenges and this was closely followed by higher levels of total IgE. Despite slightly elevated serum IgE levels, splenocytes from C57Bl/6 mice did not secrete any detectable IL-4 but produced interferon (IFN)-, in response to malaria antigen-stimulation in vitro. These data suggest that induction of IgE antibodies during murine malaria infection is genetically regulated. [source]

Variability of immunodeficiency associated with ataxia telangiectasia and clinical evolution in 12 affected patients

PEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 7 2005
G. Claret Teruel
Ataxia telangiectasia (AT) is an infrequent condition, which is difficult to diagnose in children. The objective was to describe the evolution of all affected patients controlled in our hospital and to highlight the keys for an early diagnosis considering the variability of immunological disorders. The present study is a retrospective review of all patients diagnosed and controlled of AT in our hospital. Twelve patients were found, including two couples of siblings. The most frequent reason for consultation was unstable gait. Seven patients suffered repeated infections, being pneumonia the most frequent cause of infection, followed by sinusitis. One of the patients developed Burkitt's lymphoma, and another patient, Hodgkin's lymphoma, which caused the death of the patient at the age of 11. A couple of siblings aged 17 and 22 years developed insulin-resistant diabetes mellitus. The most frequent immunity disorders were the IgG deficiency and the decrease of T lymphocytes. Seven patients were treated with non-specific gamma-globulin. By the end of the follow-up, 8 patients (ages ranged 7 to 12 years) lost gait. Molecular genetic testing was conducted in patients who are still cared for in our hospital. Clinical suspicion of this entity will lead to an early diagnosis, the treatment of complications, and to provide genetic counselling for the families. [source]