Organelles in Blastocystis that blur the distinction between mitochondria and hydrogenosomes.

addresses: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, B3H 1X5, Canada. [email protected]: PMCID: PMC2428068types: Journal Article; Research Support, Non-U.S. Gov'tOpen Access Article. This is a copy of an article published in Current Biology © Elsevier. Current Biology is available online at: http://www.sciencedirect.com/science/journal/09609822Blastocystis is a unicellular stramenopile of controversial pathogenicity in humans. Although it is a strict anaerobe, Blastocystis has mitochondrion-like organelles with cristae, a transmembrane potential and DNA. An apparent lack of several typical mitochondrial pathways has led some to suggest that these organelles might be hydrogenosomes, anaerobic organelles related to mitochondria. We generated 12,767 expressed sequence tags (ESTs) from Blastocystis and identified 115 clusters that encode putative mitochondrial and hydrogenosomal proteins. Among these is the canonical hydrogenosomal protein iron-only [FeFe] hydrogenase that we show localizes to the organelles. The organelles also have mitochondrial characteristics, including pathways for amino acid metabolism, iron-sulfur cluster biogenesis, and an incomplete tricarboxylic acid cycle as well as a mitochondrial genome. Although complexes I and II of the electron transport chain (ETC) are present, we found no evidence for complexes III and IV or F1Fo ATPases. The Blastocystis organelles have metabolic properties of aerobic and anaerobic mitochondria and of hydrogenosomes. They are convergently similar to organelles recently described in the unrelated ciliate Nyctotherus ovalis. These findings blur the boundaries between mitochondria, hydrogenosomes, and mitosomes, as currently defined, underscoring the disparate selective forces that shape these organelles in eukaryotes

Navigation system for robot-assisted intra-articular lower-limb fracture surgery

Purpose In the surgical treatment for lower-leg intra-articular fractures, the fragments have to be positioned and aligned to reconstruct the fractured bone as precisely as possible, to allow the joint to function correctly again. Standard procedures use 2D radiographs to estimate the desired reduction position of bone fragments. However, optimal correction in a 3D space requires 3D imaging. This paper introduces a new navigation system that uses pre-operative planning based on 3D CT data and intra-operative 3D guidance to virtually reduce lower-limb intra-articular fractures. Physical reduction in the fractures is then performed by our robotic system based on the virtual reduction. Methods 3D models of bone fragments are segmented from CT scan. Fragments are pre-operatively visualized on the screen and virtually manipulated by the surgeon through a dedicated GUI to achieve the virtual reduction in the fracture. Intra-operatively, the actual position of the bone fragments is provided by an optical tracker enabling real-time 3D guidance. The motion commands for the robot connected to the bone fragment are generated, and the fracture physically reduced based on the surgeon’s virtual reduction. To test the system, four femur models were fractured to obtain four different distal femur fracture types. Each one of them was subsequently reduced 20 times by a surgeon using our system. Results The navigation system allowed an orthopaedic surgeon to virtually reduce the fracture with a maximum residual positioning error of 0.95±0.3mm (translational) and 1.4∘±0.5∘ (rotational). Correspondent physical reductions resulted in an accuracy of 1.03 ± 0.2 mm and 1.56∘±0.1∘, when the robot reduced the fracture. Conclusions Experimental outcome demonstrates the accuracy and effectiveness of the proposed navigation system, presenting a fracture reduction accuracy of about 1 mm and 1.5∘, and meeting the clinical requirements for distal femur fracture reduction procedures

Nut production in Bertholletia excelsa across a logged forest mosaic: implications for multiple forest use

Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù

Vision-based real-time position control of a semi-automated system for robot-assisted joint fracture surgery

Purpose: Joint fracture surgery quality can be improved by robotic system with high-accuracy and high-repeatability fracture fragment manipulation. A new real-time vision-based system for fragment manipulation during robot-assisted fracture surgery was developed and tested. Methods: The control strategy was accomplished by merging fast open-loop control with vision-based control. This two-phase process is designed to eliminate the open-loop positioning errors by closing the control loop using visual feedback provided by an optical tracking system. Evaluation of the control system accuracy was performed using robot positioning trials, and fracture reduction accuracy was tested in trials on ex vivo porcine model.Results: The system resulted in high fracture reduction reliability with a reduction accuracy of 0.09mm (translations) and of (Formula presented.) (rotations), maximum observed errors in the order of 0.12mm (translations) and of (Formula presented.) (rotations), and a reduction repeatability of 0.02mm and (Formula presented.). Conclusions: The proposed vision-based system was shown to be effective and suitable for real joint fracture surgical procedures, contributing a potential improvement of their quality

Cerebral glucose metabolism and cognition in newly diagnosed Parkinson’s disease: ICICLE-PD study

This is the final version of the article. It first appeared from BioMed Central via http://dx.doi.org/10.1136/jnnp-2016-31391

Topical Oestrogen Keratinises The Human Foreskin and May Help Prevent HIV Infection

With the growing incidence of HIV, there is a desperate need to develop simple, cheap and effective new ways of preventing HIV infection. Male circumcision reduces the risk of infection by about 60%, probably because of the removal of the Langerhans cells which are abundant in the inner foreskin and are the primary route by which HIV enters the penis. Langerhans cells form a vital part of the body's natural defence against HIV and only cause infection when they are exposed to high levels of HIV virions. Rather than removing this natural defence mechanism by circumcision, it may be better to enhance it by thickening the layer of keratin overlying the Langerhans cells, thereby reducing the viral load to which they are exposed. We have investigated the ability of topically administered oestrogen to induce keratinization of the epithelium of the inner foreskin. Histochemically, the whole of the foreskin is richly supplied with oestrogen receptors. The epithelium of the inner foreskin, like the vagina, responds within 24 hours to the topical administration of oestriol by keratinization, and the response persists for at least 5 days after the cessation of the treatment. Oestriol, a cheap, readily available natural oestrogen metabolite, rapidly keratinizes the inner foreskin, the site of HIV entry into the penis. This thickening of the overlying protective layer of keratin should reduce the exposure of the underlying Langerhans cells to HIV virions. This simple treatment could become an adjunct or alternative to surgical circumcision for reducing the incidence of HIV infection in men

Expression and Function of Macrophage Migration Inhibitory Factor (MIF) in Melioidosis

Melioidosis is a severe tropical infection caused by the bacterium Burkholderia pseudomallei. B. pseudomallei is the major cause of community-acquired septicemia in northeast Thailand with a mortality rate in severe cases of around 40% Little is known, however, about the mechanisms of the host defense to B. pseudomallei infection. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that has emerged as an important mediator of the host defense in severe bacterial infections. In this article, we studied the expression and function of MIF both in patients with melioidosis and in mice during experimental melioidosis. We found that MIF concentrations were elevated in patients with melioidosis. Furthermore, high MIF concentrations are associated with poor outcome in patients with melioidosis. Also, in mice with experimentally induced melioidosis, we observed an upregulation of MIF concentrations. Furthermore, mice with melioidosis that were treated with a MIF blocking treatment showed lower bacterial counts in their lungs during infection. In conclusion, MIF seems to impair host defense mechanisms during melioidosis

Assessment of platelet function in patients with stroke using multiple electrode platelet aggregometry: a prospective observational study

Background There is a link between high on-treatment platelet reactivity (HPR) and adverse vascular events in stroke. This study aimed to compare multiple electrode platelet aggregometry (MEA), in healthy subjects and ischaemic stroke patients, and between patients naive to antiplatelet drugs (AP) and those on regular low dose AP. We also aimed to determine prevalence of HPR at baseline and at 3–5 days after loading doses of aspirin. Methods Patients with first ever ischaemic stroke were age and sex-matched to a healthy control group. Three venous blood samples were collected: on admission before any treatment given (baseline); at 24 h and 3–5 days after standard treatment. MEA was determined using a Mutliplate® analyser and agonists tested were arachidonic acid (ASPI), adenosine diphosphate (ADP) and collagen (COL). Results Seventy patients (mean age 73 years [SD 13]; 42 men, 28 women) were age and sex-matched to 72 healthy subjects. Thirty-three patients were on antiplatelet drugs (AP) prior to stroke onset and 37 were AP-naive. MEA results for all agonists were significantly increased in AP-naive patients compared to healthy subjects: ADP 98 ± 31 vs 81 ± 24, p < 0.005; ASPI 117 ± 31 vs 98 ± 27, p < 0.005; COL 100 ± 25 vs 82 ± 20, p < 0.005. For patients on long term AP, 33% (10/30) of patients were considered aspirin-resistant. At 3–5 days following loading doses of aspirin, only 11.1% were aspirin resistant based on an ASPI cut-off value of 40 AU*min. Conclusions Many patients receiving low dose aspirin met the criteria of aspirin resistance but this was much lower at 3–5 days following loading doses of aspirin. Future studies are needed to establish the causes of HPR and potential benefits of individualizing AP treatment based on platelet function testing

Alcohol and risk of admission to hospital for unintentional cutting or piercing injuries at home: a population-based case-crossover study

<p>Abstract</p> <p>Background</p> <p>Cutting and piercing injuries are among the leading causes of unintentional injury morbidity in developed countries. In New Zealand, cutting and piercing are second only to falls as the most frequent cause of unintentional home injuries resulting in admissions to hospital among people aged 20 to 64 years. Alcohol intake is known to be associated with many other types of injury. We used a case-crossover study to investigate the role of acute alcohol use (i.e., drinking during the previous 6 h) in unintentional cutting or piercing injuries at home.</p> <p>Methods</p> <p>A population-based case-crossover study was conducted. We identified all people aged 20 to 64 years, resident in one of three regions of the country (Greater Auckland, Waikato and Otago), who were admitted to public hospital within 48 h of an unintentional non-occupational cutting or piercing injury sustained at home (theirs or another's) from August 2008 to December 2009. The main exposure of interest was use of alcohol in the 6-hour period before the injury occurred and the corresponding time intervals 24 h before, and 1 week before, the injury. Other information was collected on known and potential confounders. Information was obtained during face-to-face interviews with cases, and through review of their medical charts.</p> <p>Results</p> <p>Of the 356 participants, 71% were male, and a third sustained injuries from contact with glass. After adjustment for other paired exposures, the odds ratio for injury after consuming 1 to 3 standard drinks of alcohol during the 6-hour period before the injury (compared to the day before), compared to none, was 1.77 (95% confidence interval 0.84 to 3.74), and for four or more drinks was 8.68 (95% confidence interval 3.11 to 24.3). Smokers had higher alcohol-related risks than non-smokers.</p> <p>Conclusions</p> <p>Alcohol consumption increases the odds of unintentional cutting or piercing injury occurring at home and this risk increases with higher levels of drinking.</p