Modeling of the diffusion MR signal in calibrated model systems and nerves

Diffusion NMR is a powerful tool for gleaning microstructural information on opaque systems. In this work, the signal decay in single‐pulsed‐field gradient diffusion NMR experiments performed on a series of phantoms of increasing complexity, where the ground truth is known a priori, was modeled and used to identify microstructural features of these complex phantoms. We were able to demonstrate that, without assuming the number of components or compartments, the modeling can identify the number of restricted components, detect their sizes with an accuracy of a fraction of a micrometer, determine their relative populations, and identify and characterize free diffusion when present in addition to the components exhibiting restricted diffusion. After the accuracy of the modeling had been demonstrated, this same approach was used to study fixed nerves under different experimental conditions. It seems that this approach is able to characterize both the averaged axon diameter and the relative population of the different diffusing components in the neuronal tissues examined. Copyright © 2013 John Wiley & Sons, Ltd.     

Regional anatomy of the pedunculopontine nucleus: Relevance for deep brain stimulation

The pedunculopontine nucleus (PPN) is currently being investigated as a potential deep brain stimulation target to improve gait and posture in Parkinson's disease. This review examines the complex anatomy of the PPN region and suggests a functional mapping of the surrounding nuclei and fiber tracts that may serve as a guide to a more accurate placement of electrodes while avoiding potentially adverse effects. The relationships of the PPN were examined in different human brain atlases. Schematic representations of those structures in the vicinity of the PPN were generated and correlated with their potential stimulation effects. By providing a functional map and representative schematics of the PPN region, we hope to optimize the placement of deep brain stimulation electrodes, thereby maximizing safety and clinical efficacy. © 2013 International Parkinson and Movement Disorder Society     

Can achievement goal theory provide a useful motivational perspective for explaining psychosocial attributes of medical students?

Background  

Psychosocial competence and frustration tolerance are important characteristics of skilled medical professionals. In the present study we explored the usefulness of applying a comprehensive motivational theory (Goal orientations), for this purpose. According to goal orientation theory, learning motivation is defined as the general goals students pursue during learning (either mastery goals - gaining new knowledge; or performance goals - gaining a positive evaluation of competence or avoiding negative evaluation). Perceived psychosocial abilities are a desirable outcome, and low frustration tolerance (LFT), is a negative feature of student behavior. The hypothesis was that the mastery goal would be positively associated with psychosocial abilities while performance goals would be positively associated with LFT.     

Epigenomics and the structure of the living genome

Eukaryotic genomes are packaged into an extensively folded state known as chromatin. Analysis of the structure of eukaryotic chromosomes has been revolutionized by development of a suite of genome-wide measurement technologies, collectively termed “epigenomics.” We review major advances in epigenomic analysis of eukaryotic genomes, covering aspects of genome folding at scales ranging from whole chromosome folding down to nucleotide-resolution assays that provide structural insights into protein-DNA interactions. We then briefly outline several challenges remaining and highlight new developments such as single-cell epigenomic assays that will help provide us with a high-resolution structural understanding of eukaryotic genomes.The past two decades have seen dramatic advances in our ability to carry out genome-wide analysis of DNA and RNA populations, first spurred by microarray technology and continuing today with deep sequencing. These technical advances have revolutionized molecular biology, with early genomic studies focused on mRNA abundance, and later studies expanding genome-wide analyses into fields ranging from cancer genome sequencing to systematic dissection of protein structure and function using massively parallel mutagenesis, selection, and sequencing. One of the most productive of these areas has been the broad area of “epigenomics,” which is the use of genome-wide assays to interrogate global patterns of cytosine methylation, chromatin state, and RNA abundance. Although small RNAs (such as siRNAs and piRNAs) and DNA modifications (such as cytosine and adenine methylation) are central to many well-characterized epigenetic inheritance paradigms, this review will focus on epigenomic insights into the folding of the genome and thus will not cover DNA modifications or RNAs.Below, we introduce the general methodologies for epigenomic analysis. Then, we discuss the structural organization of the eukaryotic genome, starting with 3C-based analyses of higher-order chromosome folding and domain organization, followed by nucleosome resolution chromosome organization (∼100- to 500-bp scale), and finally ending with insights afforded by nucleotide-resolution techniques.     

A staff support programme for rural hospitals in Nepal

ProblemDistrict hospitals in Nepal struggle to provide essential services such as caesarean sections.ApproachRetention of health workers is critical to the delivery of long-term, quality health-care services. To promote retention and enhance performance in rural public hospitals, the Government of Nepal and the Nick Simons Institute progressively implemented a rural staff support programme in remote hospitals. After competitive selection for a compulsory-service scholarship and training, family practice doctors who could do basic surgery, orthopaedics and obstetrics were hired under a binding three-year contract in each participating hospital. Comfortable living quarters and an Internet connection were provided for the resident doctors; in-service training for all staff and capacity development for each hospital’s management committee were provided.

Local setting

Nepal’s mountainous landscape, poverty and inequitable rural/urban distribution of health workers pose barriers to adequate health care.

Relevant changes

Between 2011 and 2015 family practice doctors were maintained in all seven programme hospitals. All hospitals became providers of comprehensive emergency obstetric care and served more patients. Compared with hospitals not within the programme, deliveries increased significantly (203% versus 71% increase, respectively; P = 0.002). The programme recently expanded to 14 hospitals.

Lessons learnt

A package of human resource supports can improve the retention of doctors and the use of remote hospitals. Factors contributing to the success of this programme were compulsory-service scholarship, central personnel management, performance-based incentives and the provision of comfortable living quarters.     

Patient satisfaction among spanish-speaking patients in a public health setting

Despite the growing literature on health care quality, few patient satisfaction studies have focused upon the public health setting; where many Hispanic patients receive care. The purpose of this study was to examine the differences in satisfaction between English and Spanish-speaking patients in a local health department clinical setting. We conducted a paper-based satisfaction survey of patients that visited any of the seven Jefferson County Department of Health primary care centers from March 19 to April 19, 2008. Using Chi-squared analyses we found 25% of the Spanish-speaking patients reported regularly having problems getting an appointment compared to 16.8% among English-speakers (p < .001). Results of logistic regression analyses indicated that, despite the availability of interpreters at all JCDH primary care centers, differences in satisfaction existed between Spanish and English speaking patients controlling for center location, purpose of visit, and time spent waiting. Specifically, Spanish speaking patients were more likely to report problems getting an appointment and less likely to report having their medical problems resolved when leaving their visit as compared to those who spoke English. Findings presented herein may provide insight regarding the quality of care received, specifically regarding patient satisfaction in the public health setting.