Publications by authors named "Mario Rojas"

28 Publications

  • Page 1 of 1

Refining the resolution of craniofacial dysmorphology in bipolar disorder as an index of brain dysmorphogenesis.

Psychiatry Res 2020 09 18;291:113243. Epub 2020 Jun 18.

Molecular & Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland; Jiangsu Key Laboratory of Translational Research & Therapy for Neuro-Psychiatric Disorders, College of Pharmaceutical Sciences, Soochow University, Suzhou, China. Electronic address:

As understanding of the genetics of bipolar disorder increases, controversy endures regarding whether the origins of this illness include early maldevelopment. Clarification would be facilitated by a 'hard' biological index of fetal developmental abnormality, among which craniofacial dysmorphology bears the closest embryological relationship to brain dysmorphogenesis. Therefore, 3D laser surface imaging was used to capture the facial surface of 21 patients with bipolar disorder and 45 control subjects; 21 patients with schizophrenia were also studied. Surface images were subjected to geometric morphometric analysis in non-affine space for more incisive resolution of subtle, localised dysmorphologies that might distinguish patients from controls. Complex and more biologically informative, non-linear changes distinguished bipolar patients from control subjects. On a background of minor dysmorphology of the upper face, maxilla, midface and periorbital regions, bipolar disorder was characterised primarily by the following dysmorphologies: (a) retrusion and shortening of the premaxilla, nose, philtrum, lips and mouth (the frontonasal prominences), with (b) some protrusion and widening of the mandible-chin. The topography of facial dysmorphology in bipolar disorder indicates disruption to early development in the frontonasal process and, on embryological grounds, cerebral dysmorphogenesis in the forebrain, most likely between the 10 and 15 week of fetal life.
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http://dx.doi.org/10.1016/j.psychres.2020.113243DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7487763PMC
September 2020

Association Between Early Sjögren Markers and Symptoms and Signs of Dry Eye.

Cornea 2020 Mar;39(3):311-315

Department of Ophthalmology, Miami Veterans Administration Medical Center, Miami, FL; and.

Purpose: Animal models suggest that early markers of Sjögren syndrome (EMS)-antibodies against salivary protein 1, parotid secretory protein, and carbonic anhydrase 6 (CA6)-are more accurate signals of early Sjögren when compared with classic markers (anti-Ro and anti-La). To further understand the relationship between EMS and dry eye (DE), we compared symptoms and signs of DE in subjects who tested positive versus negative for EMS.

Methods: In this cross-sectional study, patients at the Miami Veterans Affairs Eye Clinic who were tested for EMS underwent a standard ocular surface examination. Indications for EMS testing included DE symptoms in combination with dry mouth symptoms, low tear production, corneal staining, or a Sjögren disease-associated autoimmune disease. Statistical tests performed were the χ test, Fisher exact test, independent sample t test, and Spearman correlation.

Results: Seventy-three percent of 44 patients tested positive for 1 or more EMS. CA6 IgG was most frequently elevated, followed by CA6 IgM and parotid secretory protein IgG. EMS-positive versus EMS-negative subjects were more likely to escalate DE treatment past artificial tears to topical cyclosporine (n = 32, 100% vs. n = 9, 75%, P = 0.02). There were no demographic or comorbidity differences between EMS-positive and EMS-negative subjects, and marker levels did not correlate with more severe tear film measures.

Conclusions: Most of the individuals with DE tested positive for 1 or more EMS antibodies, including men and Hispanics. Future studies will be needed to understand how to incorporate EMS data into the care of an individual with DE.
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http://dx.doi.org/10.1097/ICO.0000000000002171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7007845PMC
March 2020

Involvement of OpsLTP1 from Opuntia streptacantha in abiotic stress adaptation and lipid metabolism.

Funct Plant Biol 2019 08;46(9):816-829

Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Av. Instituto Politécnico Nacional 195, Col. Playa Palo de Santa Rita Apdo, Postal 128, 23096 La Paz, B.C.S., México; and Corresponding author. Email:

Plant lipid transfer proteins (LTPs) exhibit the ability to transfer lipids between membranes in vitro, and have been implicated in diverse physiological processes associated to plant growth, reproduction, development, biotic and abiotic stress responses. However, their mode of action is not yet fully understood. To explore the functions of the OpsLTP1 gene encoding a LTP from cactus pear Opuntia streptacantha Lem., we generated transgenic Arabidopsis thaliana (L.) Heynh. plants to overexpress OpsLTP1 and contrasted our results with the loss-of-function mutant ltp3 from A. thaliana under abiotic stress conditions. The ltp3 mutant seeds showed impaired germination under salt and osmotic treatments, in contrast to OpsLTP1 overexpressing lines that displayed significant increases in germination rate. Moreover, stress recovery assays showed that ltp3 mutant seedlings were more sensitive to salt and osmotic treatments than wild-type plants suggesting that AtLTP3 is required for stress-induced responses, while the OpsLTP1 overexpressing line showed no significant differences. In addition, OpsLTP1 overexpressing and ltp3 mutant seeds stored lower amount of total lipids compared with wild-type seeds, showing changes primarily on 16C and 18C fatty acids. However, ltp3 mutant also lead changes in lipid profile and no over concrete lipids which may suggest a compensatory activation of other LTPs. Interestingly, linoleic acid (18:2ω6) was consistently increased in neutral, galactoglycerolipids and phosphoglycerolipids of OpsLTP1 overexpressing line indicating a role of OpsLTP1 in the modulation of lipid composition in A. thaliana.
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http://dx.doi.org/10.1071/FP18280DOI Listing
August 2019

Trabectome success factors.

Medicine (Baltimore) 2017 Jun;96(24):e7061

Eastern Virginia Medical School Virginia Eye Consultants, Norfolk, VA Scheie Eye Institute, University of Pennsylvania School of Medicine, Philadelphia, PA.

Our objective is to investigate which factors and patient characteristics are associated with success in Trabectome surgery.A total of 658 phakic cases with at least of 12 months follow-up were included in the analysis. Baseline demographics and medical data were collected. The main outcome measure was intraocular pressure (IOP), glaucoma medication (Rx), and secondary glaucoma surgery if any. Success was defined as IOP reduction of 20% or more from preoperative IOP and IOP < 21 mm Hg with no secondary surgery throughout the follow-up period. Risk factors for failure were determined by using univariate and multivariate cox regression.At baseline, the average IOP was 23.6 ± 7.8 mm Hg and the average number of medications was 2.6 ± 1.3 for all cases. At 12 months, the average IOP was 16.0 ± 3.6 mm Hg (P < .01) and the average number of medications was 1.8 ± 1.3 (P < .01). Based on the result of multivariate cox regression model, we found that the Trabectome + Phaco (TP) and Trabectome alone (TA) group had a 94% and 79% survival rate at 12 months, respectively. TP cases had 78% lower risk of failure than TA (95% confidence interval [CI]: 54-89), diagnosis of pseudoexfoliation glaucoma had a 54% lower risk of failure than primary open angle glaucoma patients (95% CI: 1-78). Hispanics had an estimated hazard ratio that is 60% lower than Caucasians (95% CI: 18-80); 20% of TA cases and 3% of TP cases were required to undergo additional secondary surgery (P < .01).Trabectome surgery, whether in combination with phacoemulsification cataract removal or stand alone, is associated with a significant reduction of IOP and glaucoma medication. Patients having a higher baseline IOP are expected to have a higher IOP reduction after Trabectome. Pseudoexfoliation glaucoma, combination with phacoemulsification cataract surgery and Hispanic race are factors associated with enhanced Trabectome survival.
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http://dx.doi.org/10.1097/MD.0000000000007061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5478308PMC
June 2017

Skills based evaluation of alternative input methods to command a semi-autonomous electric wheelchair.

Annu Int Conf IEEE Eng Med Biol Soc 2016 Aug;2016:4593-4596

This paper presents the evaluation, under standardized metrics, of alternative input methods to steer and maneuver a semi-autonomous electric wheelchair. The Human-Machine Interface (HMI), which includes a virtual joystick, head movements and speech recognition controls, was designed to facilitate mobility skills for severely disabled people. Thirteen tasks, which are common to all the wheelchair users, were attempted five times by controlling it with the virtual joystick and the hands-free interfaces in different areas for disabled and non-disabled people. Even though the prototype has an intelligent navigation control, based on fuzzy logic and ultrasonic sensors, the evaluation was done without assistance. The scored values showed that both controls, the head movements and the virtual joystick have similar capabilities, 92.3% and 100%, respectively. However, the 54.6% capacity score obtained for the speech control interface indicates the needs of the navigation assistance to accomplish some of the goals. Furthermore, the evaluation time indicates those skills which require more user's training with the interface and specifications to improve the total performance of the wheelchair.
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http://dx.doi.org/10.1109/EMBC.2016.7591750DOI Listing
August 2016

Necrotizing Enterocolitis and Growth in Preterm Infants Fed Predominantly Maternal Milk, Pasteurized Donor Milk, or Preterm Formula: A Retrospective Study.

Am J Perinatol 2017 06 9;34(7):676-683. Epub 2016 Dec 9.

Department of Radiology, Novant Health Forsyth Medical Center, Winston-Salem, North Carolina.

 To evaluate the association between necrotizing enterocolitis (NEC), growth, and feeding.  This is a retrospective study of 551 infants (birth weight ≤ 1,500 g, ≤32 weeks' gestation). NEC, Bell's stage ≥ 2, was confirmed by independent review of sentinel radiographs. Feeding type was defined as ≥ 50% maternal milk (MM), pasteurized donor human milk (PDHM), or preterm formula (PF). Demographic and clinical characteristics including growth were compared between the three groups. Multivariable regression analysis was performed to control variables that differed in bivariate analysis.  PDHM and PF mothers were more likely to be African-American, be enrolled in Medicaid, and have chorioamnionitis. PF mothers received antenatal steroids less frequently. NEC rates were different by feeding group (MM: 5.3%; PHDM: 4.3%; PF: 11.4%;  = 0.04). Adjusting for group differences, lower gestational age (adjusted odds ratio [aOR]: 0.85; 95% confidence interval [CI]: 0.74-0.97;  = 0.02], and PF (aOR: 2.53; 95% CI: 1.15-5.53;  = 0.02] were associated with NEC. There were no differences in other health outcomes or growth at hospital discharge.  MM and PDHM feedings, given until 34 weeks postmenstrual age, were associated with lower rates of NEC in very low birth weight infants without interfering with growth.
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http://dx.doi.org/10.1055/s-0036-1597326DOI Listing
June 2017

First Golden Hour of Life: A Quality Improvement Initiative.

Adv Neonatal Care 2016 Aug;16(4):264-72

Wake Forest University School of Medicine, Winston-Salem, North Carolina (Drs Lambeth and Rojas); Novant Health Forsyth Medical Center, Winston-Salem, North Carolina (Drs Lambeth, Rojas, and Holmes); and Duke University School of Nursing and School of Medicine, Durham, North Carolina (Dr Dail).

Background: Very low birth-weight (<1500 g) infants are vulnerable to their environment during the first hour after birth. We designed an evidence-based golden hour protocol (GHP) with a goal to stabilize and perform admission procedures within 1 hour of birth at a level IIIB neonatal intensive care unit (NICU).

Purpose: The aim of this quality improvement project was to ascertain whether an evidence-based GHP would improve care efficiency and short-term outcomes.

Methods: Rapid cycles of change using Plan Do Study Act were utilized to document progress and gain knowledge during the quality improvement project. Measures were plotted with statistical process control methods (SPC), which analyzed improvement over time.

Results: Both admission temperature and glucose-level means were within reference range throughout the project and predicted a stable process. We observed significantly decreased time to initiation of intravenous fluids and antibiotics. An upward trend of surfactant administration within the first 2 hours of life was also observed.

Implications For Practice: The use of a GHP provided an organized approach to admission procedures and care. By using a checklist and recording intervention times, NICU caregivers were more aware of time management for each intervention and were able to decrease time to initiation of intravenous fluids and antibiotics.

Implications For Research: Future research should focus on establishing normal blood pressure ranges and safe pain management during the "golden hour" and beyond. Future quality improvement should focus on improving subsequent temperature and blood glucose levels after admission umbilical artery and venous catheter placement.
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http://dx.doi.org/10.1097/ANC.0000000000000306DOI Listing
August 2016

An update on new low add multifocal intraocular lenses.

Curr Opin Ophthalmol 2016 Jul;27(4):292-7

Eastern Virginia Medical School, Virginia Eye Consultants, Norfolk, Virginia, USA.

Purpose Of Review: The purpose of this article is to provide an overview and update on recent literature regarding low-add multifocal intraocular lenses (MFIOLs).

Recent Findings: Clinical and benchwork studies involving low-add MFIOLs were reviewed. Clinical studies focused on uncorrected distance, intermediate, and near vision, along with secondary dysphotopsias. Studies done in the laboratory assessed the optical properties of various lenses, and optically replicated visual scenarios at different viewing distances.

Summary: MFIOLs continue to evolve to meet the needs of an evolving patient population. Low-add MFIOLs have been shown to improve intermediate vision, while not compromising distance vision, along with decreasing dysphotopsias. Their optical properties continue to be optimized, and with these new improvements, larger groups of patients can benefit from the range of vision provided. It is important to understand the strengths and limitations of these new MFIOLs, this review provided the most up to date review of the literature describing low-add MFIOLs. The new information provided by these reviewed articles allows the ophthalmologist to provide the best options for each individual patient.
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http://dx.doi.org/10.1097/ICU.0000000000000266DOI Listing
July 2016

The definitions of three-dimensional landmarks on the human face: an interdisciplinary view.

J Anat 2016 Mar 11;228(3):355-65. Epub 2015 Dec 11.

School of Mathematics and Statistics, The University of Glasgow, Glasgow, UK.

The analysis of shape is a key part of anatomical research and in the large majority of cases landmarks provide a standard starting point. However, while the technology of image capture has developed rapidly and in particular three-dimensional imaging is widely available, the definitions of anatomical landmarks remain rooted in their two-dimensional origins. In the important case of the human face, standard definitions often require careful orientation of the subject. This paper considers the definitions of facial landmarks from an interdisciplinary perspective, including biological and clinical motivations, issues associated with imaging and subsequent analysis, and the mathematical definition of surface shape using differential geometry. This last perspective provides a route to definitions of landmarks based on surface curvature, often making use of ridge and valley curves, which is genuinely three-dimensional and is independent of orientation. Specific definitions based on curvature are proposed. These are evaluated, along with traditional definitions, in a study that uses a hierarchical (random effects) model to estimate the error variation that is present at several different levels within the image capture process. The estimates of variation at these different levels are of interest in their own right but, in addition, evidence is provided that variation is reduced at the observer level when the new landmark definitions are used.
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http://dx.doi.org/10.1111/joa.12407DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4832301PMC
March 2016

Integrative properties of retinal ganglion cell electrical responsiveness depend on neurotrophic support and genotype in the mouse.

Exp Eye Res 2016 04 22;145:68-74. Epub 2015 Nov 22.

Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA. Electronic address:

Early stages of glaucoma and optic neuropathies are thought to show inner retina remodeling and functional changes of retinal ganglion cells (RGCs) before they die. To assess RGC functional plasticity, we investigated the contrast-gain control properties of the pattern electroretinogram (PERG), a sensitive measure of RGC function, as an index of spatio-temporal integration occurring in the inner retina circuitry subserving PERG generators. We studied the integrative properties of the PERG in mice exposed to different conditions of neurotrophic support. We also investigated the effect of genotypic differences among mouse strains with different susceptibility to glaucoma (C57BL/6J, DBA/2J, DBA/2.Gpnmb(+)). Results show that the integrative properties of the PERG recorded in the standard C57BL/6J inbred mouse strain are impaired after deficit of neurotrophic support and partially restored after exogenous neurotrophic administration. Changes in PERG amplitude, latency, and contrast-dependent responses differ between mouse strains with different susceptibility to glaucoma. Results represent a proof of concept that the PERG could be used as a tool for in-vivo monitoring of RGC functional plasticity before RGC death, the effect of neuroactive treatments, as well as for high-throughput tool for phenotypic screening of different mouse genotypes.
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http://dx.doi.org/10.1016/j.exer.2015.11.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4842137PMC
April 2016

Equipoise in Research and the Development of Neonatal Interventions for the Management of Respiratory Distress Syndrome: A Historical Perspective.

Am J Perinatol 2015 Aug 12;32(10):910-5. Epub 2015 Mar 12.

Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Wake Forest University School of Medicine, Salem, North Carolina.

The historical review of how evidence was developed for the management of respiratory distress syndrome in premature infants has not been clearly characterized. Knowledge of this process is essential to understand the role of equipoise and its influence on the decision to evaluate interventions as they were implemented in the practice of medicine. We suspect that errant approaches to clinical equipoise secondary to states of false certainty and false uncertainty have been important barriers to the timely acquisition and implementation of evidence-based knowledge necessary to improve outcomes in this fragile population of infants. When confronted with the decision to test an intervention, physicians should question whether they have lost clinical equipoise based on opinion, expertise, or observational data rather than evidence obtained from methodological inquiry; doing so facilitates reaching clinical equipoise and promotes the application of scientific methodology to answer relevant clinical questions. Timely acquisition of evidence-based knowledge can be viewed as an ethical imperative when the status quo may have negative consequences on outcomes for generations.
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http://dx.doi.org/10.1055/s-0035-1545665DOI Listing
August 2015

Aminoglycoside-mediated relaxation of the ductus arteriosus in sepsis-associated PDA.

Am J Physiol Heart Circ Physiol 2014 Sep 3;307(5):H732-40. Epub 2014 Jul 3.

Department of Pediatrics, Vanderbilt University School of Medicine and the Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee;

Sepsis is strongly associated with patency of the ductus arteriosus (PDA) in critically ill newborns. Inflammation and the aminoglycoside antibiotics used to treat neonatal sepsis cause smooth muscle relaxation, but their contribution to PDA is unknown. We examined whether: 1) lipopolysaccharide (LPS) or inflammatory cytokines cause relaxation of the ex vivo mouse DA; 2) the aminoglycosides gentamicin, tobramycin, or amikacin causes DA relaxation; and 3) newborn infants treated with aminoglycosides have an increased risk of symptomatic PDA (sPDA). Changes in fetal mouse DA tone were measured by pressure myography in response to LPS, TNF-α, IFN-γ, macrophage-inflammatory protein 2, IL-15, IL-13, CXC chemokine ligand 12, or three aminoglycosides. A clinical database of inborn patients of all gestations was analyzed for association between sPDA and aminoglycoside treatment. Contrary to expectation, neither LPS nor any of the inflammatory mediators caused DA relaxation. However, each of the aminoglycosides caused concentration-dependent vasodilation in term and preterm mouse DAs. Pretreatment with indomethacin and N-(G)-nitro-L-arginine methyl ester did not prevent gentamicin-induced DA relaxation. Gentamicin-exposed DAs developed less oxygen-induced constriction than unexposed DAs. Among 488,349 infants who met the study criteria, 40,472 (8.3%) had sPDA. Confounder-adjusted odds of sPDA were higher in gentamicin-exposed infants, <25 wk and >32 wk. Together, these findings suggest that factors other than inflammation contribute to PDA. Aminoglycoside-induced vasorelaxation and inhibition of oxygen-induced DA constriction support the paradox that antibiotic treatment of sepsis may contribute to DA relaxation. This association was also found in newborn infants, suggesting that antibiotic selection may be an important consideration in efforts to reduce sepsis-associated PDA.
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http://dx.doi.org/10.1152/ajpheart.00838.2013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4187398PMC
September 2014

Prophylactic probiotics to prevent death and nosocomial infection in preterm infants.

Pediatrics 2012 Nov 15;130(5):e1113-20. Epub 2012 Oct 15.

Department of Pediatrics, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, USA.

Background And Objective: It has been suggested that probiotics may decrease infant mortality and nosocomial infections because of their ability to suppress colonization and translocation of bacterial pathogens in the gastrointestinal tract. We designed a large double-blinded placebo-controlled trial using Lactobacillus reuteri to test this hypothesis in preterm infants.

Methods: Eligible infants were randomly assigned during the first 48 hours of life to either daily probiotic administration or placebo. Infants in the intervention group were administered enterally 5 drops of a probiotic preparation containing 10(8) colony-forming units of L reuteri DSM 17938 until death or discharge from the NICU.

Results: A total of 750 infants ≤ 2000 g were enrolled. The frequency of the primary outcome, death, or nosocomial infection, was similar in the probiotic and placebo groups (relative risk 0.87; 95% confidence interval: 0.63-1.19; P = .376). There was a trend toward a lower rate of nosocomial pneumonia in the probiotic group (2.4% vs 5.0%; P = .06) and a nonsignificant 40% decrease in necrotizing enterocolitis (2.4% vs 4.0%; P = .23). Episodes of feeding intolerance and duration of hospitalization were lower in infants ≤ 1500 g (9.6% vs 16.8% [P = .04]; 32.5 days vs 37 days [P = .03]).

Conclusions: Although L reuteri did not appear to decrease the rate of the composite outcome, the trends suggest a protective role consistent with what has been observed in the literature. Feeding intolerance and duration of hospitalization were decreased in premature infants ≤ 1500 g.
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http://dx.doi.org/10.1542/peds.2011-3584DOI Listing
November 2012

Regional variation on rates of bronchopulmonary dysplasia and associated risk factors.

ISRN Pediatr 2012 5;2012:685151. Epub 2012 Jul 5.

Department of Clinical Epidemiology and Biostatistics, School of Medicine, Pontificia Universidad Javeriana, Bogotá 110001, D.C., Colombia.

Background. An abnormally high incidence (44%) of bronchopulmonary dysplasia with variations in rates among cities was observed in Colombia among premature infants. Objective. To identify risk factors that could explain the observed high incidence and regional variations of bronchopulmonary dysplasia. Study Design. A case-control study was designed for testing the hypothesis that differences in the disease rates were not explained by differences in city-of-birth specific population characteristics or by differences in respiratory management practices in the first 7 days of life, among cities. Results. Multivariate analysis showed that premature rupture of membranes, exposure to mechanical ventilation after received nasal CPAP, no surfactant exposure, use of rescue surfactant (instead of early surfactant), PDA, sepsis and the median daily FIO(2), were associated with a higher risk of dysplasia. Significant differences between cases and controls were found among cities. Models exploring for associations between city of birth and dysplasia showed that being born in the highest altitude city (Bogotá) was associated with a higher risk of dysplasia (OR 1.82 95% CI 1.31-2.53). Conclusions. Bronchopulmonary dysplasia was manly explained by traditional risk factors. Findings suggest that altitude may play an important role in the development of this disease. Prenatal steroids did not appear to be protective at high altitude.
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http://dx.doi.org/10.5402/2012/685151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3399399PMC
August 2012

Automatic prediction of facial trait judgments: appearance vs. structural models.

PLoS One 2011 17;6(8):e23323. Epub 2011 Aug 17.

Computer Vision Center, Edifici O, Campus Bellaterra, Universidad Autonoma de Barcelona, Barcelona, Spain.

Evaluating other individuals with respect to personality characteristics plays a crucial role in human relations and it is the focus of attention for research in diverse fields such as psychology and interactive computer systems. In psychology, face perception has been recognized as a key component of this evaluation system. Multiple studies suggest that observers use face information to infer personality characteristics. Interactive computer systems are trying to take advantage of these findings and apply them to increase the natural aspect of interaction and to improve the performance of interactive computer systems. Here, we experimentally test whether the automatic prediction of facial trait judgments (e.g. dominance) can be made by using the full appearance information of the face and whether a reduced representation of its structure is sufficient. We evaluate two separate approaches: a holistic representation model using the facial appearance information and a structural model constructed from the relations among facial salient points. State of the art machine learning methods are applied to a) derive a facial trait judgment model from training data and b) predict a facial trait value for any face. Furthermore, we address the issue of whether there are specific structural relations among facial points that predict perception of facial traits. Experimental results over a set of labeled data (9 different trait evaluations) and classification rules (4 rules) suggest that a) prediction of perception of facial traits is learnable by both holistic and structural approaches; b) the most reliable prediction of facial trait judgments is obtained by certain type of holistic descriptions of the face appearance; and c) for some traits such as attractiveness and extroversion, there are relationships between specific structural features and social perceptions.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0023323PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3157350PMC
February 2012

Do rates of arthritis and chorea predict the incidence of acute rheumatic fever?

Pediatr Int 2011 Oct;53(5):742-746

Department of General Pediatrics, Divisions of Pediatric Cardiology, Neonatology and Infectious Diseases, Monroe Carell Jr. Children's Hospital at Vanderbilt, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

Background: Acute rheumatic fever (ARF), a major cause of acquired heart disease worldwide, remains a significant public health problem. However, the precise incidence of ARF in Africa, where a large number of cases occur, remains unknown. We hypothesize that focused attention on non-cardiac features of ARF, namely joint manifestations and chorea, might enhance its detection in settings with limited resources.

Methods: This hypothesis was tested by reviewing the medical records at Vanderbilt Children's Hospital from 1998 to 2008. In addition, an extensive literature review of published studies was performed to assess rates of joint findings or chorea in confirmed cases of ARF.

Results: Fifty-nine new cases of ARF were diagnosed in children at Vanderbilt from 1998 to 2008. Of these cases, 91% presented with joint manifestations or chorea, and 80% satisfied major Jones criteria findings of polyarthritis or chorea. These findings are consistent with literature published from our region and internationally.

Conclusions: Most patients presenting with ARF have either joint symptoms or chorea, features that could be recognized by community health workers and individuals with limited medical training. The referral of patients presenting with these manifestations for further evaluation might improve detection rates of ARF in resource-limited countries and lead to improved estimates of disease burden.
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http://dx.doi.org/10.1111/j.1442-200X.2011.03352.xDOI Listing
October 2011

Effect of ionic environment on the rheology of wormlike micelle solutions of mixtures of surfactants with opposite charge.

J Colloid Interface Sci 2010 Feb 13;342(1):103-9. Epub 2009 Oct 13.

Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA.

This work reports on the rheological characterization of aqueous solutions of mixtures of a cationic surfactant (hexadecyltrimethylammonium p-toluenesulfonate, CTAT), capable of forming wormlike micelles, and an anionic surfactant (sodium dodecylsulfate, SDS) when the ionic environment of the solution is altered by the addition of electrolytes. Previous work showed that mixtures CTAT/SDS exhibit a strong rheological synergy in shear flows caused by promotion of interaction between wormlike micelles by the presence of the dodecylsulfate anion. In this work, we explore the CTAT/SDS synergy in the presence of electrolytes. The effect of the added electrolyte varies with wormlike micelle concentration range and type of flow. In simple shear flows and relatively low wormlike micelle concentrations (dilute regime), electrolyte addition inhibits the shear thickening effect observed in CTAT/SDS solution. In porous media flows, which have an important elongational component, electrolyte addition results in an appreciable increase in apparent viscosity at low electrolyte concentrations. In the semi-dilute regime, electrolyte addition at low concentrations strengthens the synergy between CTAT and SDS, leading to higher shear viscosities, especially at low-shear rates. An important consequence of these results is the potential for manipulation of the rheology of solutions of wormlike micelles by induction of intermicelle associations and/or promotion of conformational changes by electrolyte addition.
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http://dx.doi.org/10.1016/j.jcis.2009.10.012DOI Listing
February 2010

Synthesis of amphiphilic dendrons and their interactions in aqueous solutions with cetyltrimethylammonium p-toluenesulfonate (CTAT).

J Colloid Interface Sci 2009 Aug 21;336(2):462-9. Epub 2009 Apr 21.

Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina.

In this work, we report synthesis and rheology of an interesting structured fluid based on the self-assembly of amphiphilic dendrons and wormlike micelles. Two amphiphilic dendrons were synthesized by the combination of aliphatic chains and polar dendritic heads. They showed different degrees of hydrophobicity and formed micelles in aqueous solution at critical micelle concentrations (CMC) of 25 and 125 ppm. The dendrons were soluble in water up to a concentration of approximately 1200 ppm, and produced no measurable increase in the viscosity of the solvent. The rheology of solutions of mixtures of each dendron with cetyltrimethylammonium p-toluenesulfonate (CTAT, a cationic surfactant) was characterized in simple shear flow. In the concentration range in which CTAT forms semidilute solutions of wormlike micelles, dendron addition produced a substantial synergy in zero-shear rate viscosity. Parallel-plate oscillatory shear measurements demonstrated that the CTAT/dendron mixtures are significantly more elastic than CTAT solutions. The viscosity synergy occurs at dendron concentrations lower than their CMC, and it is stronger for the more hydrophobic dendron. This suggests that the interactions between dendrons and wormlike micelles are basically hydrophobic, which implies attachment of dendron micelles to wormlike CTAT micelles in a manner similar to micellization of surfactants on polyelectrolytes.
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http://dx.doi.org/10.1016/j.jcis.2009.04.038DOI Listing
August 2009

Very early surfactant without mandatory ventilation in premature infants treated with early continuous positive airway pressure: a randomized, controlled trial.

Pediatrics 2009 Jan;123(1):137-42

Vanderbilt University, Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Nashville, TN 37232-2370, USA.

Background: Chronic lung disease is one of the most frequent and serious complications of premature birth. Because mechanical ventilation is a major risk factor for chronic lung disease, the early application of nasal continuous positive airway pressure has been used as a strategy for avoiding mechanical ventilation in premature infants. Surfactant therapy improves the short-term respiratory status of premature infants, but its use is traditionally limited to infants being mechanically ventilated. Administration of very early surfactant during a brief period of intubation to infants treated with nasal continuous positive airway pressure may improve their outcome and further decrease the need for mechanical ventilation.

Objective: Our goal was to determine if very early surfactant therapy without mandatory ventilation improves outcome and decreases the need for mechanical ventilation when used in very premature infants treated with nasal continuous positive airway pressure soon after birth.

Design/methods: Eight centers in Colombia participated in this randomized, controlled trial. Infants born between 27 and 31 weeks' gestation with evidence of respiratory distress and treated with supplemental oxygen in the delivery room were randomly assigned within the first hour of life to intubation, very early surfactant, extubation, and nasal continuous positive airway pressure (treatment group) or nasal continuous airway pressure alone (control group). The primary outcome was the need for subsequent mechanical ventilation using predefined criteria.

Results: From January 1, 2004, to December 31, 2006, 279 infants were randomly assigned, 141 to the treatment group and 138 to the control group. The need for mechanical ventilation was lower in the treatment group (26%) compared with the control group (39%). Air-leak syndrome occurred less frequently in the treatment group (2%) compared with the control group (9%). The percentage of patients receiving surfactant after the first hour of life was also significantly less in the treatment group (12%) compared with the control group (26%). The incidence of chronic lung disease (oxygen treatment at 36 weeks' postmenstrual age) was 49% in the treatment group compared with 59% in the control group. All other outcomes, including mortality, intraventricular hemorrhage, and periventricular leukomalacia were similar between the groups.

Conclusions: In premature infants treated with nasal continuous positive airway pressure early after birth, the addition of very early surfactant therapy without mandatory ventilation decreased the need for subsequent mechanical ventilation, decreased the incidence of air-leak syndrome, and seemed to be safe. Reduction in the need for mechanical ventilation is an important outcome when medical resources are limited and may result in less chronic lung disease in both developed and developing countries.
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http://dx.doi.org/10.1542/peds.2007-3501DOI Listing
January 2009

Shear rheology and porous media flow of wormlike micelle solutions formed by mixtures of surfactants of opposite charge.

J Colloid Interface Sci 2008 Oct 18;326(1):221-6. Epub 2008 Jul 18.

Grupo de Polímeros USB, Departamento de Ciencias de los Materiales, Universidad Simón Bolívar, Apartado 89000, Caracas 1080-A, Venezuela.

The rheology of solutions of wormlike micelles formed by oppositely charged surfactant mixtures (cationic cetyl trimethylammonium p-toluene sulfonate, CTAT, and anionic sodium dodecyl sulfate, SDS), in the dilute and semi-dilute regimes, were studied under simple shear and porous media flows. Aqueous mixtures of CTAT and SDS formed homogeneous solutions for SDS/CTAT molar ratios below 0.12. Solutions of mixtures exhibited a strong synergistic effect in shear viscosity, especially in the semi-dilute regime with respect to wormlike micelles, reaching a four order of magnitude increase in the zero-shear rate viscosity for solutions with 20 mM CTAT. Oscillatory shear results demonstrated that the microstructure of CTAT wormlike micelles is sensitive to SDS addition. The cross-over relaxation times of wormlike micelles of 20 mM CTAT solutions increased by three orders of magnitude with the addition of up to 2 mM of SDS, and the solutions became increasingly elastic. The shear thickening process observed in shear rheology became more pronounced in porous media flow due to the formation of stronger cooperative structures induced by the extensional component of the flow.
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http://dx.doi.org/10.1016/j.jcis.2008.07.022DOI Listing
October 2008

Dislocation of an enlarged fabella as uncommon cause of knee pain: a case report.

Knee 2007 Aug 9;14(4):330-2. Epub 2007 May 9.

Department of Orthopaedic and Trauma Surgery, Campus Biomedico University, Via Longoni, 83, 00155 Rome, Italy.

The fabella is a sesamoid bone that can very occasionally act as a source of atypical knee pain, often mistaken for a more common cause of clinical symptoms, such as an intra-articular loose body or an osteophyte. We report a case of symptomatic dislocation of an osteoarthritic, enlarged fabella, 4 years after total excision of the patella for a comminuted fracture, that was primarily overlooked and led to repeated diagnostic arthroscopy of the knee. A thorough history and physical examination of the joint as well as appropriate roentgenographic studies could have spared this patient an unnecessary arthroscopy and indicated the correct therapy.
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http://dx.doi.org/10.1016/j.knee.2007.03.007DOI Listing
August 2007

Effect of ionic strength on the rheological behavior of aqueous cetyltrimethylammonium p-toluene sulfonate solutions.

J Colloid Interface Sci 2007 Mar 6;307(1):221-8. Epub 2006 Nov 6.

Grupo de Polímeros USB, Departamento de Ciencias de los Materiales, Universidad Simón Bolívar, Caracas 1080A, Venezuela.

The influence of ionic environment on the rheological properties of aqueous cetyltrimethylammonium p-toluene sulfonate (CTAT) solutions has been studied under three different flow fields: simple shear, opposed-jets flow and porous media flow. Emphasis was placed in the experiments on a range of CTAT concentration in which wormlike micelles were formed. It is known that these solutions exhibit shear thickening in the semi-dilute regime, which has been explained in terms of the formation of shear-induced, cooperative structures involving wormlike micelles. In simple shear flow, the zero shear viscosity exhibits first an increase with salt addition followed by a decrease, while the critical shear rate for shear thickening increases sharply at low salt contents and tends to saturate at relatively high ionic strengths. The results are explained in terms of a competition between micellar growth induced by salt addition and changes in micellar flexibility caused by ionic screening effects. Dynamic light scattering results indicate that micelles grow rapidly upon salt addition but eventually achieve a constant size under static conditions. These observations suggest that the wormlike micelles continuously grow with salt addition, but, as they become more flexible due to electrostatic screening, the wormlike coils tend to adopt a more compact conformation. The trends observed in the apparent viscosities measured in porous media flows seem to confirm these hypotheses-but viscosity increases in the shear thickening region-and are magnified by micelle deformation induced by the elongational nature of the local flow in the pores. In opposed-jets flow, the solutions have a behavior that is close to Newtonian, which suggests that the range of strain rates employed makes the flow strong enough to destroy or prevent the formation of cooperative micellar structures.
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http://dx.doi.org/10.1016/j.jcis.2006.11.002DOI Listing
March 2007

Multiple osteochondroses of bilateral knee joints: a case report.

Knee Surg Sports Traumatol Arthrosc 2007 Apr 9;15(4):431-5. Epub 2006 Sep 9.

Department of Orthopaedic surgery, University Campus Biomedico of Rome, via E. Longoni, N. 83, 00155, Rome, Italy.

Knee injuries in young athletes include not only the typical adult bone injuries, ligament and cartilage, but also the growth plate lesions. Osteochondroses are idiopathic, self-limited disturbance of enchondral ossification in which a rapid growth spurt is present. The patella could be affected by two different kinds of osteochondroses: Kohler syndrome and Sinding-Larsen-Johansson. Here we are reporting the first case of simultaneous location of osteochondroses of the two ossification centers of both patella. A 9-year-old boy, competitive skater, presented a history of anterior knee pain involving both knees. Standard X-rays, axial patellar view, MRI and arthro-MR were performed. In order to follow the natural history of the pathology and the evolution of the healing, examinations at 2 years were repeated. We proposed the young skater a medical and a physiotherapeutic treatment based on unloading, isometric exercises, NSAID. As the symptoms improve a gradual return to competitive sports activity was allowed. The case mentioned above can be considered an atypical case because the patient suffered for a bilateral knee osteochondroses, involving simultaneously the primary ossification centre (Kohler syndrome) and the secondary ossification centre (Larsen syndrome) of the patella.
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http://dx.doi.org/10.1007/s00167-006-0180-0DOI Listing
April 2007

Randomized, multicenter trial of conventional ventilation versus high-frequency oscillatory ventilation for the early management of respiratory failure in term or near-term infants in Colombia.

J Perinatol 2005 Nov;25(11):720-4

Department of Pediatrics, Vanderbilt University, Nashville, TN 37232-2370, USA.

Objective: To determine the efficacy and safety of high-frequency oscillatory ventilation (HFOV) compared to conventional ventilation (CV) for the treatment of respiratory failure in term and near-term infants in Colombia.

Study Design: Eligible infants with moderate to severe respiratory failure were randomized to early treatment with CV or HFOV. Ventilator management and general patient care were standardized. The main outcome was neonatal death or pulmonary air leak.

Results: A total of 119 infants were enrolled (55 in the HFOV group; 64 in the CV group) during the study period. Six infants in the HFOV group (11%) and two infants in the CV group (3%) developed the primary outcome (RR: 3.6, 95% CI: 0.8-16.9). Five infants in the HFOV group (9%) and one infant in the CV (2%) died before 28 days of life (RR: 5.9 CI: 0.7-48.2). Secondary outcomes were similar between groups.

Conclusion: HFOV may not be superior to CV as an early treatment for respiratory failure in this age group. Standardization of ventilator management and general patient care may have a greater impact on the outcome in Colombia than mode of ventilation.
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http://dx.doi.org/10.1038/sj.jp.7211386DOI Listing
November 2005

Risk factors for nosocomial infections in selected neonatal intensive care units in Colombia, South America.

J Perinatol 2005 Aug;25(8):537-41

Department of Pediatrics, University of North Carolina, Chapel Hill, NC, USA.

Objective: This study was designed to identify risk factors for nosocomial infections among infants admitted into eight neonatal intensive care units in Colombia. Knowledge of modifiable risk factors could be used to guide the design of interventions to prevent the problem.

Study Design: Data were collected prospectively from eight neonatal units. Nosocomial infection was defined as culture-proven infection diagnosed after 72 hours of hospitalization, resulting in treatment with antibiotics for >3 days. Associations were expressed as odds ratios. Logistic regression was used to adjust for potential confounders.

Results: From a total of 1504 eligible infants, 80 were treated for 127 episodes of nosocomial infection. Logistic regression analysis identified the combined exposure to postnatal steroids and H2-blockers, and use of oral gastric tubes for enteral nutrition as risk factors significantly associated with nosocomial infection.

Conclusion: Nosocomial infections in Colombian neonatal intensive care units were associated with modifiable risk factors including use of postnatal steroids and H2-blockers.
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http://dx.doi.org/10.1038/sj.jp.7211353DOI Listing
August 2005

Epidemiology of nosocomial infections in selected neonatal intensive care units in Colombia, South America.

J Perinatol 2005 Aug;25(8):531-6

University of North Carolina (M.M.E., M.A.R., C.L.B.), Chapel Hill, North Carolina, USA.

Objective: The epidemiology of nosocomial infections (NI) in neonatal intensive care units in developing countries has been poorly studied. We conducted a prospective study in selected neonatal units in Colombia, SA, to describe the incidence rate, causative organisms, and interinstitutional differences.

Study Design: Data were collected prospectively from February 20 to August 30, 2001 from eight neonatal units. NI was defined as culture-proven infection diagnosed after 72 h of hospitalization, resulting in treatment with antibiotics for >3 days. Linear regression models were used to describe associations between institutional variables and NI rates.

Results: A total of 1504 infants were hospitalized for more than 72 h, and therefore, at risk for NI. Of all, 127 infections were reported among 80 patients (5.3%). The incidence density rate was 6.2 per 1000 patient-days. Bloodstream infections accounted for 78% of NIs. Gram-negative organisms predominated over gram-positive organisms (55 vs 38%) and were prevalent in infants < or =2000 g (54%). The most common pathogens were Staphylococcus epidermidis (26%) and Klebsiella pneumonia (12%).

Conclusion: Gram-negative organisms predominate in Colombia among infants <2000 g. The emergence of gram-negative organisms and their associated risk factors requires further study.
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http://dx.doi.org/10.1038/sj.jp.7211345DOI Listing
August 2005

Computed tomography-guided and arthroscopically controlled en bloc retrograde resection of a juxta-articular osteoid osteoma of the tibial plateau.

Arthroscopy 2005 Mar;21(3):351-9

Department of Orthopaedics and Traumatology, School of Medicine and Surgery, Università Campus Bio-Medico, Rome, Italy.

Osteoid osteoma represents approximately 10% to 11% of all the benign bone tumors. The localization at the articular and juxta-articular level of the knee is an atypical picture that causes both diagnostic and therapeutic problems. We present the case of an osteoid osteoma of the lateral tibial plateau just beneath the joint level. The lesion was removed by a rear-entry computed tomography (CT)-guided drill under arthroscopic control and the bony defect filled with bone graft harvested from the proximal tibial metaphysis. Postoperative CT scans at 3 months, and 1 and 2 years were performed. The result of the kneeling test to evaluate donor-site morbidity 1 year after the surgery was negative. There were no immediate or delayed complications. Currently (2 years postoperatively), the patient has no pain and has gone back to his normal active daily lifestyle and routines. The follow-up CT scan 2 years after surgery showed complete excision of the lesion and perfect positioning of the bone graft. This new approach/technique enabled us to avoid damaging the proximal structures, to examine the lesion, and to fill the bony defect. Moreover, as shown by CT scan at follow-up, iatrogenic lesions to the cartilage of the tibial plateau were not reported.
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http://dx.doi.org/10.1016/j.arthro.2004.10.004DOI Listing
March 2005

Somatic growth of preterm infants during skin-to-skin care versus traditional holding: a randomized, controlled trial.

J Dev Behav Pediatr 2003 Jun;24(3):163-8

Department of Pediatrics, Childre's Hospitak at Yale-New Haven, Connecticut, USA.

We performed this randomized trial to determine whether infants receiving skin-to-skin care (SSC) grew more rapidly and had a shorter duration of hospital stay compared with infants held by their parents in a traditional way. Infants who met eligibility criteria (
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http://dx.doi.org/10.1097/00004703-200306000-00006DOI Listing
June 2003