Search

The reaction of HCl on water ice provides a simple case for understanding dissociation and proton transfer in this non-optimal, incomplete solvation environment, playing a central role in atmospheric chemistry. This reaction has been repeatedly reported as thermally dependent, whereas the theoretical models predict a spontaneous dissociation. We examine the adsorption of HCl on ice at low temperature (50 K and 90 K) via a combination of near-edge X-ray absorption spectroscopy (NEXAFS) at the chlorine L-edge, photoemission (XPS and UPS), and reflection-adsorption infrared spectroscopy (FT-RAIRS). We show the complete dissociation of HCl into Cl(-) and H(+) through 3 hydrogen bonds, predominantly by direct reaction with water (80%) and by self-solvation (20%), in full agreement with the prediction of a barrierless process.

The coupling mechanism between the HF stretching and H(2)O bending vibrations observed in the infrared spectra of HF:H(2)O binary amorphous solids is analyzed using a simple cluster model. The intermolecular vibrational coupling derived from electrostatic potentials is one order of magnitude smaller, and of the opposite sign, than that obtained from electronic structure-based potentials. This highlights the distinctively covalent character of strong H-bonds and unveils fundamental weaknesses of electrostatic descriptions of vibrational energy transfer in liquid water and aqueous solutions.

Introduction: Major trauma is characterized by an overwhelming pro-inflammatory response and an accompanying anti-inflammatory response that lead to a state of immunosuppression, as observed after septic shock. Diminished monocyte Human Leukocyte Antigen DR (mHLA-DR) is a reliable marker of monocyte dysfunction and immunosuppression. The main objective of this study was to determine the relation between mHLA-DR expression in severe trauma patients and the development of sepsis., Methods: We conducted a prospective observational study over 23 months in a trauma intensive care unit at a university hospital. Patients with an Injury Severity Score (ISS) over 25 and age over 18 were included. mHLA-DR was assessed by flow cytometry protocol according to standardized protocol. Mann-Whitney U-test for continuous non-parametric variables, independent paired t test for continuous parametric variables and chi-square test for categorical data were used., Results: mHLA-DR was measured three times a week during the first 14 days. One hundred five consecutive severely injured patients were monitored (ISS 38 ± 17, SAPS II 37 ± 16). Thirty-seven patients (35%) developed sepsis over the 14 days post-trauma. At days 1-2, mHLA-DR was diminished in the whole patient population, with no difference with the development of sepsis. At days 3-4, a highly significant difference appeared between septic and non-septic patients. Non- septic patients showed an increase in mHLA-DR levels, whereas septic patients did not (13,723 ± 7,766 versus 9,271 ± 6,029 antibodies per cell, p = .004). Most importantly, multivariate logistic regression analysis, after adjustment for usual clinical confounders (adjusted OR 5.41, 95% CI 1.42-20.52), revealed that a slope of mHLA-DR expression between days1-2 and days 3-4 below 1.2 remained associated with the development of sepsis., Conclusions: Major trauma induced an immunosuppression, characterized by a decrease in mHLA-DR expression. Importantly, after multivariate regression logistic analysis, persistent decreased expression was assessed to be in relation with the development of sepsis. This is the first study in trauma patients showing a link between the lack of immune recovery and the development of sepsis on the basis of the standardized protocol. Monitoring immune function by mHLA-DR measurement could be useful to identify trauma patients at a high risk of infection.

Thoracic aortic mural thrombus is a rare entity and potential source of serious systemic emboli. The progress of computed tomography (CT) angiography and the current use of transesophageal echocardiography (TEE) after any embolic event have considerably increased the frequency of diagnostic and there is a growing interest about the etiopathogenesis, which is still widely misunderstood. Therapeutic management remains controversial. We present a case of floating thrombus in the thoracic aorta detected by contrast-enhanced CT scan. This thrombus was responsible for two close major embolic events and was therefore managed surgically. Finally, outcome was favorable.

We report 13 cases of coronary stent patients, undergoing a non cardiac surgery. Despite an heterogenous perioperative management of antiplatelet agents, none of these patients developed any significant complications. Recently, several case reports of postoperative drug eluting stent thrombosis have been reported. However, the actual incidence of this dramatic event is not known. This confirms the need to perform prospective studies or registries of patients with coronary stents undergoing non cardiac surgery, in order to propose evidence-based recommendations on perioperative antiplatelet management in such patients.

The authors report two cases of hepatic cirrhosis complicated by portal hypertension with splenorenal venous shunt presenting with left renal tumour that was treated by left radical nephrectomy with preservation of the shunt.

Management of the difficult adult airway is a crucial problem in anaesthesia. It is the first cause of anaesthetic mortality and morbidity. We report here the case of a patient who could only be intubated through the orbital cavity. We discuss our technique of intubation compared to the other rare procedures described in the literature. We also focus on our anaesthetic protocol and the interest of preserving spontaneous ventilation for intubation. Use of short acting anaesthetic drugs can help to achieve such conditions.

Background: Peptide therapy targets T cells directly with short peptides containing multiple T-cell receptor epitopes. Murine studies suggest T-cell anergy as the mechanism of action; however, changes in T-cell cytokine profiles may be more relevant in human beings., Objective: We sought to study the effects of peptide therapy on ex vivo antigen-specific T-cell responses., Methods: Antigen-specific T-cell lines were generated from subjects enrolled in a double-blind, placebo controlled, two-dose study of the ALLERVAX CAT therapeutic, containing Fel d 1 peptides (ImmuLogic Pharmaceutical Corp., Waltham, Mass.) (n = 7, 8, and 7, respectively, for groups receiving placebo, 75 microg, or 750 microg). Each subject had three lines propagated before and after receiving peptide therapy; antigens used were cat hair extract, Fel d 1 peptides, and tetanus toxoid (negative control). Proliferative responses and cytokine generation from each line were assessed after two restimulations with antigen and autologous antigen-presenting cells., Results: The Fel d 1 peptide lines showed a dose-dependent decrease of IL-4 production (p = 0.02 and 0.025, respectively, for the 750 microg group vs both the 75 microg and placebo groups). IL-4 production from the cat hair allergen extract lines and interferon-gamma production from both the Fel d 1 peptide lines and cat hair allergen extract lines showed no statistically significant changes. The control tetanus toxoid lines showed no changes in cytokine production; there were no significant changes in proliferation with any of the antigens in any of the treatment groups. In the clinical arm of the trial, only the 750 microg dose of peptides produced a significant response., Conclusions: Peptide therapy induces a significant, dose-dependent decrease in peptide-stimulated IL-4 production, consistent with either a shift in T-cell phenotype or peptide-specific T-cell tolerance.

The purpose of this study was to verify if, during games, the behavior of ice hockey coaches at the bantam level tends to incite players to use roughness and to infringe upon the rules of the game, as the Néron report (1977) states. The video recording of 27 games using a split-screen technique made it possible to view simultaneously the players in action as well as the coaches' behavior. Analysis of the videotapes revealed that the coaches (n = 11) at the bantam level often exhort their players to put more intensity in their physical contacts (legal body checking), but they more often encouraged them to control themselves and avoid penalties. In general, the coaches displayed very little behavior that encouraged violent actions from the players.

Release of calcium from intracellular stores of rat basophilic leukemia cells was monitored using the fluorescent probe chlortetracycline. The ability of chlortetracycline to indicate release from intracellular calcium stores was initially validated. The decrease of chlortetracycline fluorescence upon antigen-stimulation was not the result of secretion of granule-associated dye or of changes in the properties of the membranes. The chlortetracycline fluorescence signal was not influenced by Ca2+ influx across the plasma membrane. Results obtained from these chlortetracycline fluorescence measurements corresponded well with 45Ca efflux data, an indirect measurement of release of calcium from stores. Chlortetracycline was used to examine the rate of antigen-induced release of calcium from stores, the depletion of intracellular calcium stores by EGTA, and the relationship between the antigen-stimulated release of stored calcium and exocytosis. Chlortetracycline was shown to be a useful qualitative indicator for the release of intracellular calcium with a relatively rapid response time.

In brief: Two separate studies were done to determine the effects of body checking at the Pee Wee level. Study 1 evaluated eight of the smallest and eight of the largest players from leagues that allowed body checking. The players were measured for height, weight, grip strength, maximal skating speed, impact force during a body check, and speed of skating at impact. Significant morphologic differences (p <.05) between small and large players were reflected in forces of impact. Study 2 investigated the incidence and types of injuries sustained among players competing in leagues with body checking and without. In the checking leagues 55.5% of all injuries were due to body contacts, and serious injuries occurred six times more often than in nonchecking leagues. In addition, body checking accounted for 88% of the 25 fractures recorded during one hockey season.

This study concerns the effect of intravitreal injection of 1-methyl-4-phenylpyridinium ion (MPP+) on the electroretinograms (ERG) and on the levels of retinal dopamine (DA) in rabbits. The right eye was injected intravitreously with MPP+ while the other received only the vehicle and served as control. The administration of 7, 40, 70 or 700 micrograms MPP+ resulted in a dose-related decrease of the amplitude of the a and b-waves as well as the oscillatory potentials (OPs) of the ERG, down to extinction. In contrast, the retinal DA content was decreased only with the 700 micrograms MPP+ dose. Fluorescein angiography demonstrated abnormalities in the retinal circulation of all MPP+-treated eyes. These observations indicate that MPP+ causes lesions to the retinal vessels at doses non-toxic to the retinal dopaminergic neurons. These data suggest that intravitreal injection of MPP+ cannot be used to study the physiological role of retinal DA.

The influences of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on dopamine content in the retina and the striatum of monkeys, as well as retinal responses to flash stimulation were studied. Dopamine depletion was observed in the striatum, while retinal dopamine content was similar to controls. The electroretinograms and the oscillatory potentials remained normal, even in monkeys presenting a severe Parkinsonian syndrome, in concordance with the biochemical data. It is proposed that the retinal dopaminergic system is less sensitive to the toxic effects of MPTP than the nigro-striatal pathway.

A Forum For Our Readers Forum is intended to provide a sounding board for our readers. Perhaps you have a special way to treat a common medical problem, or you may want to air your views on a controversial topic. You may object to an article that we have published, or you may want to support one. You may have a new trend to report, identified through an interesting case or a series of patients. Whatever your ideas, we invite you to send them to us. Illustrative figures are welcomed. Address correspondence to Forum, THE PHYSICIAN AND SPORTSMEDICINE, 4530 W 77th St, Minneapolis, MN 55435.