Laparoscopic surgery in a patient with Fontan physiology

Laparoscopic surgery represents a significant advance in surgical technique, but a number of physiologic sequelae result from positioning and insufflation. These physiologic changes may be more significant in patients with complex congenital heart disease. We present the anesthetic management of a patient with Fontan physiology who successfully underwent two separate laparoscopic procedures.     

Chicken interleukin-21 is costimulatory for T cells and blocks maturation of dendritic cells

In mammals, interleukin-21 (IL-21) is an immunomodulatory cytokine with pleiotropic effects on the proliferation, differentiation and effector functions of T, B, NK and dendritic cells. A cDNA encoding the chicken orthologue of IL-21 (chIL-21) was cloned by RT-PCR from RNA isolated from activated chicken splenocytes and consists of 438 nucleotides, encoding an open reading frame of 145 amino acids (aa). Chicken IL-21 has 20-30% aa identity to its orthologues in mammals, Xenopus and fish, but is more highly conserved within Aves (50-80%). The four alpha-helical bundle structure of mammalian IL-21 appears to be conserved in the predicted chicken protein, as are the four cysteine residues required for the formation of two disulphide bridges. A glutamine residue in aa position 129, which has been implicated in the binding of IL-21 to the IL-2 receptor γ-chain in mammals, is also conserved. ChIL-21 is expressed in most lymphoid tissues, predominantly by CD4+ TCRαβ+ T cells. As in mammals, chIL-21 synergistically enhances T-cell proliferation and inhibits maturation of dendritic cells.     

Prospects for understanding immune-endocrine interactions in the chicken

Despite occupying the same habitats as mammals, having similar ranges of body mass and longevity, and facing similar pathogen challenges, birds have a different repertoire of organs, cells, molecules and genes of the immune system when compared to mammals. In other words, birds are not "mice with feathers", at least not in terms of their immune systems. Here we discuss differences between immune gene repertoires of birds and mammals, particularly those known to play a role in immune-endocrine interactions in mammals. If we are to begin to understand immune-endocrine interactions in the chicken, we need to understand these repertoires and also the biological function of the proteins encoded by these genes. We also discuss developments in our ability to understand the function of dendritic cells in the chicken; the function of these professional antigen-presenting cells is affected by stress in mammals. With regard to the endocrine system, we describe relevant chicken pituitary-adrenal hormones, and review recent findings on the expression of their receptors, as these receptors play a crucial role in modulating immune-endocrine interactions. Finally, we review the (albeit limited) work that has been carried out to understand immune-endocrine interactions in the chicken in the post-genome era.     

Real-time haptic-teleoperated robotic system for motor control analysis

A versatile teleoperated robotic system was created as an assessment device for testing upper-extremity motor control adaptation using different control strategies. While many systems display output virtually on a computer monitor, this system was designed to output in three-dimensional physical space. The system accepts haptic force and torque input, and outputs robot end-effector displacements and rotations in three spatial dimensions. Benefits of this system include flexibility to conduct a variety of dissimilar tasks and reality of user feedback in physical space. Two separate experiments validated the teleoperated robotic system. The first experiment tested unimanual human motor control and the second tested bimanual motor control. This teleoperated robotic system can be used as an assessment device to study neuromuscular adaptability via a variety of control strategies providing a new and functional approach to human motor control analysis.     

CO(2)-induced c-Fos expression in brainstem preprotachykinin mRNA containing neurons

Tachykinin peptides are found in brainstem regions involved in central chemoreception and they may play a modulatory role in ventilatory response to hypercapnia. We determined whether tachykinin peptide containing neurons are activated by CO(2) by combining in situ hybridization and immunohistochemistry (IHH). Experiments were performed in 21-day-old rats exposed to 12% CO(2) for 1 h. c-Fos expression was identified by IHH on free floating sections (40 microm) that were mounted and then hybridized with anti-sense 35S labeled ribonucleotide probe of the rat preprotachykinin A (PPT-A) gene. Sections were analyzed for expression of the PPT-A gene, c-Fos protein and colocalization of PPT-A gene with c-Fos protein. Within the chemosensory region of the nucleus tractus solitarius (nTS), 19% of c-Fos positive cells expressed PPT-A mRNA after hypercapnic loading. In medullary raphe nuclei, 64% of c-Fos positive cells expressed the PPT-A gene after exposure to CO(2), while 21% of c-Fos labeled neurons in parapyramidal nuclei also expressed PPT-A mRNA. These results indicate that a subpopulation of CO(2) activated neurons within the nTS and in the parapyramidal and midline regions of the ventral aspect of the medulla oblongata express the PPT-A gene, suggesting that these are substance P- or neurokinin A-containing neurons. Furthermore, these peptides may play a role in modulation of respiratory and cardiovascular responses to changes in CO(2)/H(+) content of the extracellular fluid.     

Gram‐scale synthesis and efficient purification of 13C‐labeled levoglucosan from 13C glucose

¹³C‐Labeled levoglucosan has been synthesized and purified in good yield, and on the gram scale in one step from commercially available ¹³C glucose. This one‐step protocol uses 2‐chloro‐1,3‐dimethylimidazolinium chloride that serves to selectively activate the anomeric carbon toward substitution reactions. The labeled glucose is then smoothly converted to the anhydroglucose. Purification is efficiently achieved on large scale by chromatography on silica gel.     

Improved antibody aggregate removal by hydroxyapatite chromatography in the presence of polyethylene glycol

This paper reports a method for improving the effectiveness of aggregate removal from monoclonal antibodies by the use of hydroxyapatite (HA) in the presence of polyethylene glycol (PEG). PEG preferentially enhances aggregate retention, thereby increasing the degree of separation between aggregated and non-aggregated antibodies. PEG has a similar effect on ion exchangers but only half the enhancement observed with HA. The HA method is suitable for preparation of aggregate-free IgG and IgM monoclonal antibodies for research, diagnostic, or therapeutic applications.