Quantitative RT-PCR profiling of the Rabbit Immune Response: Assessment of Acute Shigella flexneri Infection

Quantitative reverse transcription PCR analysis is an important tool to monitor changes in gene expression in animal models. The rabbit is a widely accepted and commonly used animal model in the study of human diseases and infections by viral, fungal, bacterial and protozoan pathogens. Only a limited number of rabbit genes have, however, been analyzed by this method as the rabbit genome sequence remains unfinished. Recently, increasing coverage of the genome has permitted the prediction of a growing number of genes that are relevant in the context of the immune response. We hereby report the design of twenty-four quantitative PCR primer pairs covering common cytokines, chemoattractants, antimicrobials and enzymes for a rapid, sensitive and quantitative analysis of the rabbit immune response. Importantly, all primer pairs were designed to be used under identical experimental conditions, thereby enabling the simultaneous analysis of all genes in a high-throughput format. This tool was used to analyze the rabbit innate immune response to infection with the human gastrointestinal pathogen Shigella flexneri. Beyond the known inflammatory mediators, we identified IL-22, IL-17A and IL-17F as highly upregulated cytokines and as first responders to infection during the innate phase of the host immune response. This set of qPCR primers also provides a convenient tool for monitoring the rabbit immune response during infection with other pathogens and other inflammatory conditions

Role of the Carotid Chemoreceptors in the Hyperpnea of Exercise in the Cat

The role of the carotid chemoreceptors in the hyperpnea of exercise was investigated. The activity of the sinus nerve of the cat was monitored while the blood supply to the carotid body was controlled independently of the systemic circulation. By this technique, fluctuations in the arterial blood gases during a short interval of exercise induced by electrical stimulation of hindlimb muscles were unable to affect the chemoreceptor activity. While minute ventilation increased by an average of 51%, chemoreccptor discharge was found to be unchanged in 12 experiments, 6 while perfusing with normoxic blood and 6 while perfusing with hypoxic blood. Thus, it must be concluded that alteration of carotid chemoreceptor sensitivity does not occur during artificially induced exercise in anesthetized cats. However, the difference in the time course of ventilation following the initiation of artificially induced exercise between cats and other species does not allow it to be ruled out in other species, including man. Indirect evidence is against such a role

Mathematical Models and Their Applications in Medicine

This paper emphasises the fact that mathematical modelling techniques have important applications in routine medical practice and medical education. It is argued that the development of mathematical models should be more closely linked to experimentation and that techniques based on computer simulation can extend the range of applicable models to models based on nonlinesr differential equations which are the largest class of models in biological work. Model have an important role in hypothesis testing and in the development of indirect methods for measuring physiological quantities. The important of model validation is stressed

CD40 Signaling of Monocyte Inflammatory Cytokine Synthesis Through an ERK1/2-Dependent Pathway: A Target of Interleukin (IL)-4 and IL-10 Anti- Inflammatory Action

Ligation of CD40 on monocytes through its interaction with CD40 ligand (CD154) present on activated T helper cells, results in activation of monocyte inflammatory cytokine synthesis and rescue of monocytes from apoptosis induced through serum deprivation. Both of these consequences of CD40 stimulation have been shown to be dependent on the induction of protein tyrosine kinase activity. CD40-mediated activation of protein tyrosine kinase activity and subsequent inflammatory cytokine production are abrogated by treatment of monocytes with the T helper type 2 cytokines interleukin 4 (IL- 4) and interleukin 10 (IL-10). In the current study we demonstrate that stimulation of monocytes through CD40 resulted in the phosphorylation and activation of the extracellular signal-regulated kinases 1 and 2 (ERK1/2) mitogen-activated protein kinases, whereas phosphorylation of mitogen- activated protein kinases family members p38 and c-Jun N-terminal kinase was not observed in response to this stimuli over the time course examined. PD98059, an inhibitor of the upstream activator of ERK1/2, the MAP/ERK kinase MEK1/2, suppressed IL-1β and tumor necrosis factor-α production in a dose- dependent fashion. Pretreatment of monocytes with IL-4 and IL-10 inhibited CD40-mediated activation of ERK1/2 kinase activity when used individually, and are enhanced in effectiveness when used in combination. Together, the data demonstrate that CD40-mediated induction of IL-1β and tumor necrosis factor-α synthesis is dependent on a MEK/ERK pathway which is obstructed by signals generated through the action of IL-4 and IL-10