Modulators of the structural dynamics of the retinoid X receptor to reveal receptor function

Retinoid X receptors (RXRalpha, -beta, and -gamma) occupy a central position in the nuclear receptor superfamily, because they form heterodimers with many other family members and hence are involved in the control of a variety of (patho)physiologic processes. Selective RXR ligands, referred to as rexinoids, are already used or are being developed for cancer therapy and have promise for the treatment of metabolic diseases. However, important side effects remain associated with existing rexinoids. Here we describe the rational design and functional characterization of a spectrum of RXR modulators ranging from partial to pure antagonists and demonstrate their utility as tools to probe the implication of RXRs in cell biological phenomena. One of these ligands renders RXR activity particularly sensitive to coactivator levels and has the potential to act as a cell-specific RXR modulator. A combination of crystallographic and fluorescence anisotropy studies reveals the molecular details accounting for the agonist-to-antagonist transition and provides direct experimental evidence for a correlation between the pharmacological activity of a ligand and its impact on the structural dynamics of the activation helix H12. Using RXR and its cognate ligands as a model system, our correlative analysis of 3D structures and dynamic data provides an original view on ligand actions and enables the establishment of mechanistic concepts, which will aid in the development of selective nuclear receptor modulators.     

Prophylaxis of venous thromboembolic disease in high-risk orthopedic surgery

Venous thromboembolism (VTE) is a worldwide public health problem, with an annual incidence of 1-2 cases/1,000 individuals in the general population and a 1-5% associated mortality. Orthopedic surgery is a major surgical risk factor for VTE, but the problem is more important for patients with hip and knee joint replacement, multiple traumatisms, severe damage to the spine, or large fractures. Thromboprophylaxis is defined as the strategy and actions necessary to diminish the risk of VTE in high-risk orthopedic surgery. Antithrombotics may prevent VTE. At the end of this paper, we describe a proposal of thromboprophylaxis actions for patients requiring high-risk orthopedic surgery, based on the opinion of specialists in Orthopedics and Traumatology who work with high-risk orthopedic surgery patients. A search for evidence about this kind of surgery was performed and a 100-item inquiring instrument was done in order to know the opinions of the participants. Then, recommendations and considerations were built. In conclusion, this document reviews the problem of VTE in high-risk orthopedic surgery patients and describes the position of the Colegio Mexicano de Ortopedia y Traumatología related to VTE prevention in this setting.     

New silver polypyridyl complexes: synthesis, characterization and biological activity on Leishmania mexicana

Leishmania parasites are the causal agents of leishmaniasis that currently threatens 350 million people in 88 different countries, in the absence of an effective drug. In order to continue the development of transition metal complexes with planar ligands that show interactions with DNA and activity against Leishmania parasites, the synthesis of the complexes [Ag(dpq)2]NO3 (1) and [Ag(dppz)2]NO3 (2), which were obtained by the reaction of silver nitrate with dpq and dppz, respectively, in a 1:2 molar ratio is reported. These complexes were characterized by elemental analysis and 1H-NMR, IR, and UV-vis spectroscopies. The most probable structure for these complexes is tetrahedral, with two molecules of ligand coordinated to the silver atom and a nitrate as a counter ion. Affinity studies of DNA vs. bovine albumin were carried out, and a strong interaction of the complexes with DNA was observed. Bioassays were undertaken in vitro on promastigotes of Leishmania (L.) mexicana exposed to the silver complexes for 48 h. At 10 micromol/L complex 2 induced a leishmanicidal effect (LD23), whilst complex 1 reduced the parasites growth rate by 55% (LD55). These findings suggest that biological activity could be associated with the interaction of the complexes with the parasitic DNA.     

Late-onset cytomegalovirus-associated interstitial nephritis in a kidney transplant

Cytomegalovirus is the most important viral infection in kidney transplants, but rarely affects the allograft after the sixth month posttransplantation. We present a patient who developed renal failure eighteen months posttransplant; a kidney biopsy showed cytomegalovirus inclusions, acute tubular necrosis and mild interstitial nephritis. After intravenous ganciclovir, renal function transiently improved. Cytomegalovirus pp65 antigen was weekly reported as negative. One month later another biopsy was performed due to renal failure. The findings were consistent with tubular atrophy and severe interstitial nephritis. No cytomegalovirus cellular inclusions were found on histology, including immunohistochemical and polymerase chain reaction studies; pp65 antigen studies were persistently negative. Despite an attempt to recover renal function with steroid therapy, the patient restarted hemodialysis 20 months posttransplantation. This report suggests that cytomegalovirus should be considered as a late cause of kidney failure even in the absence of infection-related symptoms. The irreversible allograft damage can be caused despite the successful eradication of the virus with intravenous ganciclovir.     

Helicobacter pylori infection and gastroduodenal lesions in patients with systemic lupus erythematosus

Clinical Rheumatology - The aim of this study was to determine the frequency of Helicobacter pylori in SLE patients and to compare clinical characteristics and gastroduodenal lesions in patients...     

Criss cross heart in a congenitally corrected transposition of the great arteries

Criss cross heart is an extremely rare anomaly accounting for less than 0.1% of congenital heart disease. It is characterized by an abnormal rotation of the heart on its long axis. Almost always there are associated cardiac anomalies such as pulmonary stenosis, ventricular septal defect, ventriculoarterial connection discord or hypoplasia of the tricuspid valve or right ventricle and thereby presenting in the neonatal period. We present a case of a 22 year old woman with a congenitally corrected transposition of great arteries and a criss cross heart.     

Musculoskeletal infections caused by Aerococcus urinae: a case-based review

Clinical Rheumatology - Aerococcus are Gram-positive bacteria that have been historically misidentified using standard techniques. We report a case of a 63-year-old man with septic oligoarthritis...     

Association between the HTR1A rs6295 gene polymorphism and suicidal behavior: an updated meta-analysis

European Archives of Psychiatry and Clinical Neuroscience - Several association studies have indicated that the HTR1A gene is associated with suicidal behavior (SB). Thus, a systematic assessment...