Impact of sphingomyelin acyl chain (16:0 vs 24:1) on the interfacial properties of Langmuir monolayers: a PM-IRRAS study

Membrane structure is a key factor for the cell`s physiology, pathology, and therapy. Evaluating the importance of lipid species such as N-nervonoyl sphingomyelin (24:1-SM) —able to prevent phase separation— to membrane structuring remains a formidable challenge. This is the first report in which polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS) is applied to investigate the lipid-lipid interactions in 16:0 vs 24:1-SM monolayers and their mixtures with 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol (Chol) (DOPC/SM/Chol 2:1:1). From the results we inferred that the cis double bond (Δ15) in 24:1-SM molecule diminishes intermolecular H-bonding and chain packing density compared to that of 16:0-SM. In ternary mixtures containing 16:0-SM, the relative intensity of the two components of the Amide I band reflected changes in the H-bonding network due to SM-Chol interactions. In contrast, the contribution of the main components of the Amide I band in DOPC/24:1-SM/Chol remained as in 24:1-SM monolayers, with a larger contribution of the non-H-bonded component. The most interesting feature in these ternary films is that the Cdouble bondO stretching mode of DOPC appeared with an intensity similar to that of SM Amide I band in DOPC/16:0-SM/Chol monolayers (a two-phase [Lo/Le] system), whereas an extremely low intensity of the Cdouble bondO band was detected in DOPC/24:1-SM/Chol monolayers (single Le phase). This is evidence that the unsaturation in 24:1-SM affected not only the conformational properties of acyl chains but also the orientation of the chemical groups at the air/water interface. The physical properties and overall H-bonding ability conferred by 24:1-SM may have implications in cell signaling and binding of biomolecules.Fil: Vázquez, Romina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química; ArgentinaFil: Daza Millone, Maria Antonieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Pavinatto, Felippe J.. Universidade de Sao Paulo; BrasilFil: Fanani, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; Argentina. Universidad Catolica de Córdoba. Facultad de Medicina. Departamento de Química Biologica; ArgentinaFil: Oliveira, Osvaldo N. Jr.. Universidade de Sao Paulo; BrasilFil: Vela, Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Maté, Sabina María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias Médicas. Instituto de Investigaciones Bioquímicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentin

The role of rapid maxillary expansion in the promotion of oral and general health

Rapid maxillary expansion (RME) is an effective orthopedic procedure that can be used to address problems concerned with the growth of the midface. This procedure also may produce positive side effects on the general health of the patient. The aim of the present consensus paper was to identify and evaluate studies on the changes in airway dimensions and muscular function produced by RME in growing patients. A total of 331 references were retrieved from a database search (PubMed). The widening of the nasal cavity base after midpalatal suture opening in growing patients allows the reduction in nasal airway resistance with an improvement of the respiratory pattern. The effects of RME on the upper airway, however, have been described as limited and local, and these effects become diminished farther down the airway, possibly as a result of soft-tissue adaptation. Moreover, limited information is available about the long-term stability of the airway changes produced by RME. Several studies have shown that maxillary constriction may play a role in the etiology of more severe breathing disorders such as obstructive sleep apnea (OSA) in growing subjects. Early orthodontic treatment with RME is able to reduce the symptoms of OSA and improve polysomnographic variables. Finally, early orthopedic treatment with RME also is beneficial to avoid the development of facial skeletal asymmetry resulting from functional crossbites that otherwise may lead to functional and structural disorders of the stomatognathic system later in life

Determining the use of prophylactic antibiotics in breast cancer surgeries : a survey of practice

Q3Q2Background: Prophylactic antibiotics (PAs) are beneficial to breast cancer patients undergoing surgery because they prevent surgical site infection (SSI), but limited information regarding their use has been published. This study aims to determine the use of PAs prior to breast cancer surgery amongst breast surgeons in Colombia. Methods: An online survey was distributed amongst the breast surgeon members of the Colombian Association of Mastology, the only breast surgery society of Colombia. The scope of the questions included demographics, clinical practice characteristics, PA prescription characteristics, and the use of PAs in common breast surgical procedures. Results: The survey was distributed amongst eighty-eight breast surgeons of whom forty-seven responded (response rate: 53.4%). Forty surgeons (85.1%) reported using PAs prior to surgery of which >60% used PAs during mastectomy, axillary lymph node dissection, and/or breast reconstruction. Surgeons reported they targeted the use of PAs in cases in which patients had any of the following SSI risk factors: diabetes mellitus, drains in situ, obesity, and neoadjuvant therapy. The distribution of the self-reported PA dosing regimens was as follows: single pre-operative fixed-dose (27.7%), single preoperative dose followed by a second dose if the surgery was prolonged (44.7%), single preoperative dose followed by one or more postoperative doses for >24 hours (10.6%), and single preoperative weight-adjusted dose (2.1%). Conclusion: Although this group of breast surgeons is aware of the importance of PAs in breast cancer surgery there is a discrepancy in how they use it, specifically with regards to prescription and timeliness of drug administration. Our findings call for targeted quality-improvement initiatives, such as standardized national guidelines, which can provide sufficient evidence for all stakeholders and therefore facilitate best practice medicine for breast cancer surgery

Intramuscular Administration of a Synthetic CpG-Oligodeoxynucleotide Modulates Functional Responses of Neutrophils of Neonatal Foals

Neutrophils play an important role in protecting against infection. Foals have age-dependent deficiencies in neutrophil function that may contribute to their predisposition to infection. Thus, we investigated the ability of a CpG-ODN formulated with Emulsigen to modulate functional responses of neutrophils in neonatal foals. Eighteen foals were randomly assigned to receive either a CpG-ODN with Emulsigen (N = 9) or saline intramuscularly at ages 1 and 7 days. At ages 1, 3, 9, 14, and 28, blood was collected and neutrophils were isolated from each foal. Neutrophils were assessed for basal and Rhodococcus equi-stimulated mRNA expression of the cytokines interferon-γ (IFN-γ), interleukin (IL)-4, IL-6, and IL-8 using real-time PCR, degranulation by quantifying the amount of β-D glucuronidase activity, and reactive oxygen species (ROS) generation using flow cytometry. In vivo administration of the CpG-ODN formulation on days 1 and 7 resulted in significantly (P<0.05) increased IFN-γ mRNA expression by foal neutrophils on days 3, 9, and 14. Degranulation was significantly (P<0.05) lower for foals in the CpG-ODN-treated group than the control group at days 3 and 14, but not at other days. No effect of treatment on ROS generation was detected. These results indicate that CpG-ODN administration to foals might improve innate and adaptive immune responses that could protect foals against infectious diseases and possibly improve responses to vaccination.The open access fee for this work was funded through the Texas A&M University Open Access to Knowledge (OAK) Fund