The sepsis syndrome is a systemic host inflammatory response accompanied by organ dysfunction in response to invading microbial pathogens. The host recognizes both danger and pathogens through its pattern recognition receptors on immune cells. These receptors bind to pathogen- (PAMP) and danger- (DAMP) associated molecular patterns derived from microbes and host tissues, respectively. These processes set in motion a cascade of events in host cells and tissue, which activate multiple cytokines that serve as activators of the host inflammatory response as well as eventually lead to resolution of the response if the host recovers. The following article describes some of these DAMPs and PAMPs, and how they activate pathways that activate the host cytokine immune response to injury and infection.

The fetus, which develops within a fluid-filled amniotic sac, relies on the placenta for respiratory gas exchange rather than the lungs. While not involved in fetal oxygenation, fetal breathing movements (FBM) nevertheless have an important role in lung growth and in development of respiratory muscles and neural regulation. FBM are regulated differently in many respects than postnatal respiration, which results from the unique intrauterine environment. Prominent distinctions of FBM include its episodic nature and apnea-sensitivity to hypoxia. The latter characteristic is the basis for using FBM in the assessment of fetuses at risk for hypoxic injury. At birth, the transition to continuous postnatal respiration involves a fall in temperature, gaseous distention of the lungs, activation of the Hering-Breuer reflexes, and functional connectivity of afferent O2 chemoreceptor activity with respiratory motoneurons and arousal centers. Importantly, exposure to drugs or adverse conditions in utero not only can change patterns of FBM but also can lead to epigenetic dysregulation in postnatal respiration. Such changes, can blunt respiratory and arousal defenses against hypoxic challenges in sleep. Thus, fetal hypoxia and/or drug exposure may in later life dispose sleeping infants, children, and adults to hypertension, diabetes mellitus, brain injury, and sudden death.

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