Lane Medical Library

Pneumothorax in Liberia: Complications of Tuberculosis.

West J Emerg Med. 2013 May;14(3):233-235

Authors: Grossman DB, Nasrallah E

Abstract
Tuberculosis (TB) is a known cause of secondary pneumothorax. In areas with endemic TB, complications from the disease, including pneumothorax, are increasing in prevalence. We present the cases of 3 patients (ages 32 years, 17 years, and 3 months) seen in the emergency department at John F. Kennedy Medical Center in Monrovia, Liberia, West Africa. Each presented with shortness of breath and cough, and with some degree of respiratory distress. Airway compromise was present with tracheal or mediastinal deviation. Each patient underwent tube thoracostomy with improvement in pneumothorax and respiratory status.

PMID: 23687541 [PubMed - as supplied by publisher]

The Role of Polyphosphate in Thermophilic Synechococcus sp. from Microbial Mats.

J Bacteriol. 2013 May 17;

Authors: Gomez-Garcia MR, Fazeli F, Grote A, Grossman AR, Bhaya D

Abstract
Synechococcus OS-B' , a thermophilic unicellular cyanobacterium, recently isolated from the microbial mats in Octopus Spring (Yellowstone National Park), induces a suite of genes, including phosphatases and transporters, in response to phosphorus (P) starvation. Here we describe two different approaches to examine the ability of Synechococcus OS-B' to synthesize and breakdown polyphosphate (poly P), a key storage compound in many prokaryotes. First, we developed a transformation protocol to create mutants in the polyphosphate kinase (ppk), the major enzyme responsible for the synthesis of poly P. The ppk mutant exhibited a pleiotropic phenotype with defects in poly P accumulation, aberrant levels of pho regulon transcripts, growth defects and changes in cell size and exopolysaccharide levels, among others. Second, we measured transcripts of ppk and ppx (encoding the polyphosphatase) directly from mat samples and found that the levels varied dramatically over a diel cycle. We also used Western blot analysis to quantify levels of PPK and PPX and found that these enzymes differentially accumulated during the diel cycle. Levels of polyphosphate kinase peaked at night, while polyphosphatase levels were highest during the early morning hours. We hypothesize that the opposing activities of these two enzymes allow cells to store and utilize poly P to optimize growth over a diel cycle.

PMID: 23687278 [PubMed - as supplied by publisher]

Acculturation and overweight-related attitudes and behavior among obese hispanic adults in the United States.

Obesity (Silver Spring). 2012 Nov 6;

Authors: New C, Xiao L, Ma J

Abstract
OBJECTIVE: US Hispanics bear a disproportionate burden of excess body weight and associated morbidity, making obesity prevention and control in this population a public health priority. Development of culturally appropriate weight loss interventions requires understanding the influence of acculturation on attitudes and behavior related to obesity and weight loss. DESIGN AND METHODS: Using data from the National Health and Nutrition Examination Survey (2001-2004), we analyzed the associations of country of birth and language usage with weight perception, weight dissatisfaction, intention to lose weight, and intended weight loss of clinical significance among obese Hispanic adults (>20 years of age; unweighted n = 675) in multivariable logistic regression analyses. RESULTS: US birth was significantly associated with correct weight perception (odds ratio [OR], 4.45; 95% confidence interval [CI], 2.16-9.17) and weight dissatisfaction (OR = 2.95; 95% CI = 1.63-5.35). Compared with Spanish-speaking only, obese Hispanics, bilingual, obese Hispanics were more likely to attempt weight loss (OR = 2.78; 95% CI = 1.43-5.40) and achieve clinically significant weight loss (OR = 3.94; 95% CI = 1.51-10.3). CONCLUSIONS: The findings suggest that lack of acculturation as measured by foreign birth and limited English proficiency may contribute to within-ethnicity health inequality among obese Hispanics, even after controlling for a variety of sociodemographic characteristics, including education and income, differential healthcare access and use, and health status. Further studies should examine the underlying mechanisms, thereby informing culturally competent intervention strategies targeted at obese US Hispanics.

PMID: 23687100 [PubMed - as supplied by publisher]

A transparent electrode based on a metal nanotrough network.

Nat Nanotechnol. 2013 May 19;

Authors: Wu H, Kong D, Ruan Z, Hsu PC, Wang S, Yu Z, Carney TJ, Hu L, Fan S, Cui Y

Abstract
Transparent conducting electrodes are essential components for numerous flexible optoelectronic devices, including touch screens and interactive electronics. Thin films of indium tin oxide-the prototypical transparent electrode material-demonstrate excellent electronic performances, but film brittleness, low infrared transmittance and low abundance limit suitability for certain industrial applications. Alternatives to indium tin oxide have recently been reported and include conducting polymers, carbon nanotubes and graphene. However, although flexibility is greatly improved, the optoelectronic performance of these carbon-based materials is limited by low conductivity. Other examples include metal nanowire-based electrodes, which can achieve sheet resistances of less than 10Ω □(-1) at 90% transmission because of the high conductivity of the metals. To achieve these performances, however, metal nanowires must be defect-free, have conductivities close to their values in bulk, be as long as possible to minimize the number of wire-to-wire junctions, and exhibit small junction resistance. Here, we present a facile fabrication process that allows us to satisfy all these requirements and fabricate a new kind of transparent conducting electrode that exhibits both superior optoelectronic performances (sheet resistance of ∼2Ω □(-1) at 90% transmission) and remarkable mechanical flexibility under both stretching and bending stresses. The electrode is composed of a free-standing metallic nanotrough network and is produced with a process involving electrospinning and metal deposition. We demonstrate the practical suitability of our transparent conducting electrode by fabricating a flexible touch-screen device and a transparent conducting tape.

PMID: 23685985 [PubMed - as supplied by publisher]

PLA2G3 promotes mast cell maturation and function.

Nat Immunol. 2013 May 20;14(6):527-529

Authors: Starkl P, Marichal T, Galli SJ

PMID: 23685814 [PubMed - as supplied by publisher]

Identification of gene microarray expression profiles in patients with chronic graft-versus-host disease following allogeneic hematopoietic cell transplantation.

Clin Immunol. 2013 May 1;148(1):124-135

Authors: Kohrt HE, Tian L, Li L, Alizadeh AA, Hsieh S, Tibshirani RJ, Strober S, Sarwal M, Lowsky R

Abstract
Chronic graft-versus-host disease (GVHD) results in significant morbidity and mortality, limiting the benefit of allogeneic hematopoietic cell transplantation (HCT). Peripheral blood gene expression profiling of the donor immune repertoire following HCT may provide associated genes and pathways thereby improving the pathophysiologic understanding of chronic GVHD. We profiled 70 patients and identified candidate genes that provided mechanistic insight in the biologic pathways that underlie chronic GVHD. Our data revealed that the dominant gene signature in patients with chronic GVHD represented compensatory responses that control inflammation and included the interleukin-1 decoy receptor, IL-1 receptor type II, and genes that were profibrotic and associated with the IL-4, IL-6 and IL-10 signaling pathways. In addition, we identified three genes that were important regulators of extracellular matrix. Validation of this discovery phase study will determine if the identified genes have diagnostic, prognostic or therapeutic implications.

PMID: 23685278 [PubMed - as supplied by publisher]

An Unsolved Mystery: The Target-Recognizing RNA Species of MicroRNA Genes.

Biochimie. 2013 May 14;

Authors: Chen CZ

Abstract
MicroRNAs (miRNAs) are an abundant class of endogenous ∼ 21-nucleotide (nt) RNAs. These small RNAs are produced from long primary miRNA transcripts -- pri-miRNAs -- through sequential endonucleolytic maturation steps that yield precursor miRNA (pre-miRNA) intermediates and then the mature miRNAs. The mature miRNAs are loaded into the RNA-induced silencing complexes (RISC), and guide RISC to target mRNAs for cleavage and/or translational repression. This paradigm, which represents one of major discoveries of modern molecular biology, is built on the assumption that mature miRNAs are the only species produced from miRNA genes that recognize targets. This assumption has guided the miRNA field for more than a decade and has led to our current understanding of the mechanisms of target recognition and repression by miRNAs. Although progress has been made, fundamental questions remain unanswered with regard to the principles of target recognition and mechanisms of repression. Here I raise questions about the assumption that mature miRNAs are the only target-recognizing species produced from miRNA genes and discuss the consequences of working under an incomplete or incorrect assumption. Moreover, I present evolution-based and experimental evidence that support the roles of pri-/pre-miRNAs in target recognition and repression. Finally, I propose a conceptual framework that integrates the functions of pri-/pre-miRNAs and mature miRNAs in target recognition and repression. The integrated framework opens experimental enquiry and permits interpretation of fundamental problems that have so far been precluded.

PMID: 23685275 [PubMed - as supplied by publisher]

Feedforward Regulation Ensures Stability and Rapid Reversibility of a Cellular State.

Mol Cell. 2013 May 14;

Authors: Doncic A, Skotheim JM

Abstract
Cellular transitions are important for all life. Such transitions, including cell fate decisions, often employ positive feedback regulation to establish and stabilize new cellular states. However, positive feedback is unlikely to underlie stable cell-cycle arrest in yeast exposed to mating pheromone because the signaling pathway is linear, rather than bistable, over a broad range of extracellular pheromone concentration. We show that the stability of the pheromone-arrested state results from coherent feedforward regulation of the cell-cycle inhibitor Far1. This network motif is effectively isolated from the more complex regulatory network in which it is embedded. Fast regulation of Far1 by phosphorylation allows rapid cell-cycle arrest and reentry, whereas slow Far1 synthesis reinforces arrest. We expect coherent feedforward regulation to be frequently implemented at reversible cellular transitions because this network motif can achieve the ostensibly conflicting aims of arrest stability and rapid reversibility without loss of signaling information.

PMID: 23685071 [PubMed - as supplied by publisher]

Comparison of tricalcium phosphate cement and cancellous autograft as bone void filler in acetabular fractures with marginal impaction.

Injury. 2013 May 14;

Authors: Leucht P, Castillo AB, Bellino MJ

Abstract
OBJECTIVE: To compare clinical and radiological outcome between acetabular fractures with marginal impaction that were treated with either cancellous bone graft (CBG) or tricalcium phosphate cement (TPC) as bone void filler. DESIGN: Retrospective study. PATIENTS: Forty-three patients with acetabular fractures with marginal impaction. INTERVENTION: Eighteen patients received cancellous bone graft and 25 patients received tricalcium phosphate cement as bone void filler. MAIN OUTCOME MEASUREMENT: Clinical outcome was assessed using the Merle d'Aubigne score and Short-form-36. Radiographs were evaluated for postoperative reduction, arthritis grade and development of heterotopic ossification. RESULTS: Forty-three patients met the inclusion criteria. There was no significant difference in the demographics, laterality, fracture type, associated injuries, surgical approach and postoperative quality of reduction between the groups. At final follow-up, a significantly higher number of patients in the cancellous bone graft group exhibited signs of moderate to severe post-traumatic arthritis (CBG: 6 (33%) vs. TPC: 4 (20%), p=0.007) and required a total hip arthroplasty (CBG: 4 (22.2%) vs. TPC: 1 (5%), p=0.08). There was no significant difference between the two groups in the SF-36 score and the modified Merle d'Aubigne score. CONCLUSION: Patients with acetabular fractures with marginal impaction treated with tricalcium phosphate cement exhibit a significantly lower incidence of post-traumatic arthritis when compared to patients treated with cancellous bone graft. LEVEL OF EVIDENCE: III.

PMID: 23684351 [PubMed - as supplied by publisher]

Upper Bound on the Modal Material Loss Rate in Plasmonic and Metamaterial Systems.

Phys Rev Lett. 2013 May 3;110(18):183901

Authors: Raman A, Shin W, Fan S

Abstract
A better understanding of optical loss in plasmonic and metamaterial systems is of increasing importance for both basic and applied research in a broad range of topics including sensors, antennas, optical interconnects, and photovoltaics. In this Letter, we use a photonic band formalism for plasmonics to exactly derive a fundamental upper bound on the nonradiative material loss rate of modes in plasmonic, polaritonic, and metamaterial systems. This bound is purely defined by material properties and cannot be overcome by device design. Moreover it is frequency dependent in the presence of multiple Lorentz poles. We numerically verify this bound through direct calculations for a range of plasmonic systems, including optical antennas where the bound places fundamental performance constraints.

PMID: 23683195 [PubMed - as supplied by publisher]

The Dying Lone Wolf.

J Palliat Med. 2013 May 19;

Authors: Khoo SY

PMID: 23683131 [PubMed - as supplied by publisher]

Progress in understanding mood disorders: optogenetic dissection of neural circuits.

Genes Brain Behav. 2013 May 17;

Authors: Lammel S, Tye KM, Warden MR

Abstract
Major depression is characterized by a cluster of symptoms that includes hopelessness, low mood, feelings of worthlessness, and inability to experience pleasure. The lifetime prevalence of major depression approaches 20%, yet current treatments are often inadequate both because of associated side effects and because they are ineffective for many people. In basic research, animal models are often used to study depression. Typically, experimental animals are exposed to acute or chronic stress to generate a variety of depression-like symptoms. Despite its clinical importance, very little is known about the cellular and neural circuits that mediate these symptoms. We review recent progress and highlight some studies that have begun tracing a functional neuronal circuit diagram that may prove essential in establishing novel treatment strategies in mood disorders. First, we shed light on the complexity of mesocorticolimbic dopamine responses to stress by discussing two recent studies reporting that optogenetic activation of midbrain dopamine neurons can induce or reverse depression-related behaviors. Second, we describe the role of the lateral habenula circuitry in the pathophysiology of depression. Finally, we discuss how the prefrontal cortex controls limbic and neuromodulatory circuits in mood disorders.

PMID: 23682971 [PubMed - as supplied by publisher]

Comment on Basal Cell Carcinoma Rebound After Cessation of Vismodegib in an Individual With Basal Cell Nevus Syndrome.

Dermatol Surg. 2013 May 17;

Authors: Ally MS, Wysong A, Tang JY, Aasi S

PMID: 23682843 [PubMed - as supplied by publisher]

Development and validation of a single-cell network profiling assay-based classifier to predict response to induction therapy in paediatric patients with de novo acute myeloid leukaemia: a report from the Children's Oncology Group.

Br J Haematol. 2013 May 20;

Authors: Lacayo NJ, Alonzo TA, Gayko U, Rosen DB, Westfall M, Purvis N, Putta S, Louie B, Hackett J, Cohen AC, Cesano A, Gerbing R, Ravindranath Y, Dahl GV, Gamis A, Meshinchi S

Abstract
Single cell network profiling (SCNP) is a multi-parameter flow cytometry technique for simultaneous interrogation of intracellular signalling pathways. Diagnostic paediatric acute myeloid leukaemia (AML) bone marrow samples were used to develop a classifier for response to induction therapy in 53 samples and validated in an independent set of 68 samples. The area under the curve of a receiver operating characteristic curve (AUCROC ) was calculated to be 0·85 in the training set and after exclusion of induction deaths, the AUCROC of the classifier was 0·70 (P = 0·02) and 0·67 (P = 0·04) in the validation set when induction deaths (intent to treat) were included. The highest predictive accuracy was noted in the cytogenetic intermediate risk patients (AUCROC 0·88, P = 0·002), a subgroup that lacks prognostic/predictive biomarkers for induction response. Only white blood cell count and cytogenetic risk were associated with response to induction therapy in the validation set. After controlling for these variables, the SCNP classifier score was associated with complete remission (P = 0·017), indicating that the classifier provides information independent of other clinical variables that were jointly associated with response. This is the first validation of an SCNP classifier to predict response to induction chemotherapy. Herein we demonstrate the usefulness of quantitative SCNP under modulated conditions to provide independent information on AML disease biology and induction response.

PMID: 23682827 [PubMed - as supplied by publisher]

Coronary Sinus Obstruction after Atrioventricular Canal Defect Repair.

Congenit Heart Dis. 2013 May 20;

Authors: Peng DM, Sun HY, Hanley FL, Olson I, Punn R

Abstract
The coronary sinus can become obstructed with any instrumentation at or near the ostium such as in atrioventricular canal defect repairs. This complication may lead to a wide range of consequences including dyspnea, angina, myocardial infarction, and sudden death. The following report illustrates the importance of careful perioperative echocardiographic evaluation of the coronary sinus in procedures that may affect the sinus and its ostium.

PMID: 23682752 [PubMed - as supplied by publisher]