Temperature-dependent variations of ligand-receptor contact points in hAT(1).

Photoaffinity labelling is regularly used to investigate proteins, including peptidergic G protein-coupled receptors (GPCR). To this purpose benzophenone photolabels have been widely used to identify many contact residues in ligand-binding pockets. The three-dimensional binding environment of the human angiotensin II type 1 receptor hAT(1) has been determined using an iterative methionine mutagenesis strategy based on the photochemical properties and preferential incorporation of benzophenone onto methionine. This has led to the construction of a ligand-bound receptor structure. The present study investigated the effect of temperature on the accessibility of some of these contact points. The hAT(1) receptor and two representative Met mutants (H256M-hAT(1) and F293M-hAT(1)) from the iterative mutagenesis study were photolabelled with the benzophenone-ligand (125)I-[Sar(1), Bpa(8)]AngII at temperatures ranging from - 15 degrees C to 37 degrees C. Labelled receptors were partially purified and digested with cyanogen bromide to identify the contact points or segments. There were no changes in receptor contacts or labelling in the 7th transmembrane domains (TMD) of hAT(1) and F293M-hAT(1) across the temperature range. However, a temperature-dependent change in the ligand-receptor contact of H256M-hAT(1) was observed. At - 15 degrees C, H256M labelling was identical to that of hAT(1), indicating that the interaction was specific to the 7th TMD. Significant labelling changes were observed at higher temperatures and at 37 degrees C labelling occurred almost exclusively at mutated residue H256M-hAT(1) in the 6th TMD. Simultaneous competitive labelling of different areas of this target protein indicated that the ligand-receptor structure became increasingly fluctual at physiological temperatures, while a more compact, low mobility, and low energy conformation prevailed at low temperatures.

Being prepared for a pregnant code blue.

Cardiopulmonary arrest is rare in pregnancy. To provide the most proficient care to a pregnant woman requiring cardiopulmonary resuscitation, nurses must first understand the physiologic changes that normally occur in pregnant women. This article reviews the physiologic adjustments made by the human body during pregnancy and the manner in which these can affect efforts during resuscitation. Preparation and organization are essential in implementing care during resuscitation of a pregnant woman, which is a crisis situation for everyone involved.

Impact of Mycobacterium avium complex prophylaxis on the incidence of mycobacterial infections and transfusion-requiring anemia in an HIV-positive population.

Disseminated Mycobacterium avium complex (MAC) infection is common in persons with advanced HIV infection and can be prevented by prophylactic use of rifabutin; however, routine prophylaxis is costly and incompletely effective. Chronic anemia is a common manifestation of MAC infection. We conducted a retrospective population study of the annual incidence of MAC bacteremia and blood transfusion for anemia in a regional HIV-positive population before and after the introduction of rifabutin to determine the effect of MAC prophylaxis on the incidence of transfusion-requiring anemia. The HIV-infected patient populations in 1992 and 1993 were comparable in number, severity of immunodeficiency, and zidovudine (ZDV) use. The use of rifabutin for MAC prophylaxis for those with CD4 T-lymphocyte counts < 100/microl increased from 17.2% in 1992 to 33.7% in 1993 (p < 0.001), whereas diagnostic surveillance for MAC bacteremia was stable. In 1993, there was a decrease in the number of HIV-infected persons from whom MAC was isolated (10 vs. 26, p = 0.004), and a significant decrease in the number of patients transfused for anemia (15 vs. 35, p = 0.002), number of transfusion episodes, and numbers of units transfused, associated with significant cost and resource savings. Adoption of MAC prophylaxis was followed by a significant decrease in the number of diagnosed MAC infections and in transfusion requirements in an HIV-positive population with sustained surveillance and similar levels of immunodeficiency, which may represent a health and economic benefit of effective [correction of defective] MAC prophylaxis in a population at risk.

[Lingual orthodontics: why is it progressing?]. / L'orthodontie linguale: pourquoi est-elle en progrès?

At the early stages of the 80's, most of the practitioners and the patients have been seduced by lingual orthodontic. But the difficulties of the technic have rapidly given a disappointment. Today ten years later the authors present the progress which have been realized: the evolution of the brackets, the accuracy of their placement in the lab procedure with the new targ, the making of the wire, the patient's comfort increase. The placement brackets are customized by making an anatomical resin pad. Placement of the brackets have evoluted from a quantized system in two dimensions (Targ 1) to a no quantized system in three dimensions (Class System) and finally to a real quantized system in three dimensions (Targ 2 with a compass of thickness with measures the first order band). Data System DALI (Drawing Arch Lingual Ideal) allows to draw the exact design of the wire. A video tape shows the different laboratory and clinical phases. By using light cured periodontal protection like Barricaid from Caulk: the patients have a greater adaptation with their appliance. All this progress give to lingual orthodontic credibility. Lingual is a reality to day and it's the first concept with customized brackets extremely accuracy, full quantized in the three orders, using the computer progress.

[Invisible orthodontics: lingual orthodontics]. / L'orthodontie invisible: l'orthodontie linguale.

After an historical, a description of the appliance and the problems met in lingual orthodontics, the authors show that it has come to maturity. Indirect bonding is one of the main elements contributing to success. A large iconography illustrates the different stages of the laboratory and presents an overview of the clinical possibilities of lingual orthodontics.

[Lingual orthodontics: a system for positioning the appliances in the laboratory]. / Orthodontie linguale: systèmes de positionnement des attaches au laboratoire.

The author presents the advantages and the drawbacks of two systems of lingual brackets positioning which allows to obtain a very good finish of the treatments. The Class System is a protocol made from a Set-Up but which does not allow the bonding of the teeth with unfilled resins. The other system uses the T.A.R.G. with the Thicknesses Measure Appliance and the Ideal Drawing of Lingual Arch program; it allows to program the torque, the angulations, the heights and the thicknesses (from the bottom of the throat to the vestibular side) of each tooth.