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The standard flight level for commercial airliners is ∼12 km (40 kft; air pressure: ∼ 200 hPa), the maximum certification altitude of modern airliners may be as high as 43-45 kft. Loss of structural integrity of an airplane may result in sudden depressurization of the cabin potentially leading to hypoxia with loss of consciousness of the pilots. Specialized breathing masks supply the pilots with oxygen. The aim of this study was to experimentally simulate such sudden depressurization to maximum design altitude in a pressure chamber while measuring the arterial and brain oxygenation saturation (SaO(2) and StO(2)) of the pilots. Ten healthy subjects with a median age of 50 (range 29-70) years were placed in a pressure chamber, breathing air from a cockpit mask. Pressure was reduced from 753 to 148 hPa within 20 s, and the test mask was switched to pure O(2) within 2 s after initiation of depressurization. During the whole procedure SaO(2) and StO(2) were measured by pulse oximetry, respectively near-infrared spectroscopy (NIRS; in-house built prototype) of the left frontal cortex. During the depressurization the SaO(2) dropped from median 93% (range 91-98%) to 78% (62-92%) by 16% (6-30%), while StO(2) decreased from 62% (47-67%) to 57% (43-62%) by 5% (3-14%). Considerable drops in oxygenation were observed during sudden depressurization. The inter-subject variability was high, for SaO(2) depending on the subjects' ability to preoxygenate before the depressurization. The drop in StO(2) was lower than the one in SaO(2) maybe due to compensation in blood flow.

Cell adhesion molecules (CAMs) are proteins mediating cell-cell or cell-extracellular matrix (ECM) interactions. CAMs are traditionally divided into four groups, the cadherins, the selectins, the integrins and CAMs belonging to the immunoglobulin superfamily (IgSF). The present chapter describes CAMs belonging to IgSF, that exclusively or in part, are expressed in the nervous system. The chapter includes descriptions of myelin protein zero (P0), integrin-associated protein (CD47), neuroplastin, activated leukocyte-cell adhesion molecule (ALCAM), melanoma cell adhesion molecule (MCAM), myelinassociated glycoprotein (MAG), the neural cell adhesion molecules 1 and 2 (NCAM, NCAM2), Down Syndrome cell adhesion molecule (DSCAM) and Down Syndrome cell adhesion molecule-like-1 (DSCAML1), sidekick 1 and 2 (SDK1, SDK2), signal-regulatory proteins (SIRPs), nectins, nectin-like proteins (necls), and members of the CTX, IgLON, Robo, contactin, and L1 families. The individual descriptions include sections describing the expression, isoforms, structure, posttranslational modifications, homo- and heterophilic binding partners, signaling and functions of the individual CAMs. The chapter demonstrates CAMs to be more than simple regulators of adhesion. Many CAMs are important mediators of intracellular signal transduction, and CAMs are involved in many biological phenomena including migration, proliferation, and differentiation of cells, as well as axonal guidance, neurite outgrowth,and synaptic plasticity and maturation.

The Functional Diversity of Interacting Receptors Conference was sponsored by the New York Academy of Sciences and held in Washington, D.C. on May 25-28,1994. The conference was chaired by Abel Lajtha, Ph.D., Center for Neurochemistry, Nathan S. Kline Institute, and Leo Abood, Ph.D., Department of Pharmacology, University of Rochester. Approximately 80 researchers and clinicians attended. Attendees came from throughout the United States and Europe. The conference focused on the functional significance of receptor diversity, by addressing the genetic regulation and expression of receptor subtypes; the differential functional characteristics of neurons with distinct subtypes; second messenger and ion channel diversity associated with receptor isoforms; species and regional neuroanatomic differences in receptor subtypes; receptor changes associated with chronic exposure to agonists and antagonists and occurring with age and pathologic states; and the interaction of different receptors in functional regulation. Since our knowledge of the structural, genetic, and functional features of the nicotinic cholinergic receptors appears to be more advanced than that of other receptors, the emphasis of the conference was on cholinergic receptors and their interaction with other receptors. Also included were presentations dealing with adrenergic, dopaminergic, histaminergic, gabaminergic, excitatory amino acid, and peptidergic receptors and their interactions and functional implications in health and disease., Annals of New York Academy of Sciences, Volume 757.

Contents: Structural considerations; Cerebrospinal fluid; Substrates for brain metabolism; Ion movements; Factors influencing barrier function; Spaces in the central nervous system., Prepared in cooperation with New York State Research Inst. for Neurochemistry and Drug Addiction, N.Y., and Columbia Univ., New York, Dept. of Biochemistry.