Cardiac arrhythmia: a simple conceptual framework

This review presents a simple trigger-substrate model of arrhythmogenesis and its application to the generation of reentrant ventricular arrhythmias. We demonstrate its broad applicability to the understanding of arrhythmic phenomena in a wide range of both hereditary and acquired arrhythmic disorders.     

Delayed fixation of displaced type II and III pediatric femoral neck fractures

Background:

Time from injury to fixation of femoral neck fractures has been postulated as a vital determinant for rate of complications; however, no prospective study is available in the English literature. Delay, unfortunately, is inevitable in developing countries. The aim of the present study is to retrospectively review the outcome after delayed fixation of displaced type II and III femoral neck fractures in children.

Materials and Methods:

Using a standard assessment chart, we retrospectively reviewed medical records of all pediatric patients having femoral neck fractures presenting to our institution from June 1999 to May 2006. Inclusion criteria were children between 5 and 15 years of age sustaining displaced Delbet type II and III femoral neck fractures having a complete follow-up of at least 2 years. Patients with known metabolic disease, poliomyelitis or cerebral palsy, were excluded from the study. After application of inclusion and exclusion criteria, 22 patients having 22 fractures (13 type II and 9 type III) were studied. Surgery could be performed after a mean delay of 11.22 days (ranging from 2 to 21 days). Closed reduction was achieved in 14 cases and 8 cases required open reduction through anterolateral approach.

Result:

Osteonecrosis was noted in eight patients (36.37%) who included two of nine patients (22.22%) operated in the first week, three of eight patients (37.51%) operated in the second week, and three of five patients (60%) operated in the third week of injury. Nonunion was seen in four (18.18%) cases, and two of them were associated with failure of implants. One was treated by valgus osteotomy and the other by Meyer''s procedure. Fractures united in both children but the latter developed avascular necrosis. Functional results, as assessed using Ratliff''s criteria, were good in 14 (63.63%), fair in 2 (9%), and poor in 6 (27.27%) patients.

Conclusion:

Delay in fixation, type of fracture, and ability to achieve and maintain reduction are factors primarily responsible for the outcome. We also found that delay after the first week further adversely affects the outcome.     

The CITRA research-practice consensus-workshop model: exploring a new method of research translation in aging

PURPOSE: On the basis of the experience of an extensive community-based research partnership in New York City, we developed an innovative process for bridging the gap between aging-related research and practice, using a consensus-workshop model. DESIGN AND METHODS: We adapted the traditional scientific consensus-workshop model to include translation of the research into nontechnical language and the involvement of practitioners in the process. We then applied the model to the specific issue of falls prevention among community-dwelling older adults. RESULTS: The dialogue and interaction among researchers and practitioners provided new insights beyond a traditional research review. Practitioners offered astute guidance for future research based on their day-to-day field experience. IMPLICATIONS: The recommendations that emerged from the workshop demonstrated the value of close interaction between the aging-related research and practice communities. The consensus-conference model has significant potential to establish a bridge between the worlds of research and practice in a variety of settings.     

The CITRA pilot studies program: mentoring translational research

PURPOSE: We developed an innovative pilot studies program to foster partnerships between university researchers and agencies serving older people in New York City. The development of researchers willing to collaborate with frontline service agencies and service agencies ready to partner with researchers is critical for translating scientific research into evidence-based practice that benefits community-dwelling older adults. DESIGN AND METHODS: We adapted the traditional academic pilot studies model to include key features of community-based participatory research. RESULTS: In partnership with a network of 265 senior centers and service agencies, we built a multistep program to recruit and educate scientific investigators and agencies in the principles of community-based research and to fund research partnerships that fulfilled essential elements of research translation from university to community: scientific rigor, sensitivity to community needs, and applicability to frontline practice. We also developed an educational and monitoring infrastructure to support projects. IMPLICATIONS: Pilot studies programs developing community-based participatory research require an infrastructure that can supplement individual pilot investigator efforts with centralized resources to ensure proper implementation and dissemination of the research. The financial and time investment required to maintain programs such as those at the Cornell Institute for Translational Research on Aging, or CITRA, may be a barrier to establishing similar programs.     

Trichobézoard gastrique géant

Introduction

Bezoars are clusters of ingested foreign bodies that form in the digestive tract; especially in the stomach.

Case presentation

A young girl aged 13 consulted for an epigastric mass. The abdominal ultrasound showed a heterogeneous intragastric mass and a CT scan revealed a gray mass, impregnated by the orally ingested contrast product. Fibroscopy confirmed the diagnosis of trichobezoar. An attempt to remove the trichobezoar by endoscopy was unsuccessful and a laparotomy with gastrotomy enabled the extraction of a huge stomach-shaped trichobezoar.

Discussion

Traditional factors usually involve gastric emptying disorders, problems following gastrectomy, a fibre-rich diet or gastric antisecretory drugs. Eating hair or other non-digestible materials or excessive consumption of indigestible foods may also lead to a bezoar. Fibroscopy remains the best technique for diagnosis and classification of bezoars. An abdominal CT scan will be used in cases of suspected intestinal obstruction or where injury may be involved, revealing the granite-like appearance of the bezoar in the stomach. Treatment is based on endoscopy, relayed by surgery in case of failure.     

Genome-Wide Transposon Mutagenesis Indicates that Mycobacterium marinum Customizes Its Virulence Mechanisms for Survival and Replication in Different Hosts

The interaction of environmental bacteria with unicellular eukaryotes is generally considered a major driving force for the evolution of intracellular pathogens, allowing them to survive and replicate in phagocytic cells of vertebrate hosts. To test this hypothesis on a genome-wide level, we determined for the intracellular pathogen Mycobacterium marinum whether it uses conserved strategies to exploit host cells from both protozoan and vertebrate origin. Using transposon-directed insertion site sequencing (TraDIS), we determined differences in genetic requirements for survival and replication in phagocytic cells of organisms from different kingdoms. In line with the general hypothesis, we identified a number of general virulence mechanisms, including the type VII protein secretion system ESX-1, biosynthesis of polyketide lipids, and utilization of sterols. However, we were also able to show that M. marinum contains an even larger set of host-specific virulence determinants, including proteins involved in the modification of surface glycolipids and, surprisingly, the auxiliary proteins of the ESX-1 system. Several of these factors were in fact counterproductive in other hosts. Therefore, M. marinum contains different sets of virulence factors that are tailored for specific hosts. Our data imply that although amoebae could function as a training ground for intracellular pathogens, they do not fully prepare pathogens for crossing species barriers.     

Therapeutic role of Ricinus communis L. and its bioactive compounds in disease prevention and treatment

Ricinus communis L.(R. communis), commonly known as castor oil plant, is used as a traditional natural remedy or folkloric herb for the control and treatment of a wide range of diseases around the globe. Various studies have revealed the presence of diverse phytochemicals such as alkaloids.flavonoids, terpenes, saponins,phenolic compounds such as kaempferol, gallic acid, ricin, rutin, lupeol, ricinoleic acid, pinene, thujone and gentisic acid.These phytochemicals have been responsible for pharmacological and therapeutic effects,including anticancer, antimicrobial, insecticidal, antioxidant, anti-diabetic, antinociceptive,anti-inflammatory. bone regenerative, analgesic, and anticonvulsant activity. R. communis harbours phytochemicals which have been shown to target peroxisome proliferator activated receptor(PPAR), nuclear factor NF-κ-B, cytochrome p450, P38 mitogen-activated protein kinases kinase(p38 MAPK), tumor protein P53, B-cell lymphoma-extra-large(Bcl-xL) and vascular endothelial growth factor receptor-2(VEGFR-2). Considering its wide variety of phytochemicals, its pharmacological activity and the subsequent clinical trials, R. communis could be a good candidate for discovering novel complementary drugs. Further experimental and advanced clinical studies are required to explore the pharmaceutical, beneficial therapeutic and safety prospects of R. communis with its phytochemicals as a herbal and complementary medicine for combating various diseases and disorders.     

Assessment of dermal exposure during airless spray painting using a quantitative visualisation technique

The range of dermal exposure to non-volatile compounds during spray painting was studied in a semi-experimental study involving three enterprises and 12 painters. A fluorescent tracer was added to the paint and deposition of the tracer on clothing and uncovered parts of the skin was assessed using video imaging and processing techniques. A container (volume 36 m(3)) was sprayed with a colourless laquer (varnish) containing 66.7 mg/l fluorescent whitening agent. All painters sprayed the outside of the container. Nine painters repeated the painting a second time and five also sprayed the inside of the container. The painters wore white Tyvek coveralls, but no gloves. Duration of spraying the outside ranged from 4 to 21 min with a mean of 10 min and the amount of paint sprayed ranged from 3.0 to 12.8 l (mean 6.6 l). The mass of tracer deposited on the coverall ranged from 2.2 to 471 microg (90th percentile 256 microg), whereas, mass deposited on skin (i.e. the hands, wrists, and face) ranged from 0.01 to 52 microg tracer (90th percentile 20 microg). The quantity of tracer on the coverall was three times higher after spraying the inside of the container compared to spraying the outside, whereas the quantity on the skin was similar in both cases. On average 10% of the surface area of the coverall and skin was exposed during spraying the outside. Exposures, expressed in units of mass per area exposed were slightly higher for skin compared to coverall.In this study, deposited mass of tracer was correlated with an alternative exposure metric, i.e. surface area exposed multiplied by the duration of exposure, which has been proposed as a surrogate for uptake. Using a quantitative fluorescent tracer technique, it could be demonstrated that body parts which showed the lowest mass of tracer had the highest exposure as mass per surface area. Compared to other techniques which only determine mass, the ability to identify and quantify the actual surface area exposed is a clear advantage of the quantitative fluorescent tracer technique.