European society of intensive care medicine study of therapeutic hypothermia (32-35°C) for intracranial pressure reduction after traumatic brain injury (the Eurotherm3235Trial)

Background

Severe malaria remains a major cause of global morbidity and mortality. Despite the use of potent anti-parasitic agents, the mortality rate in severe malaria remains high. Adjunctive therapies that target the underlying pathophysiology of severe malaria may further reduce morbidity and mortality. Endothelial activation plays a central role in the pathogenesis of severe malaria, of which angiopoietin-2 (Ang-2) has recently been shown to function as a key regulator. Nitric oxide (NO) is a major inhibitor of Ang-2 release from endothelium and has been shown to decrease endothelial inflammation and reduce the adhesion of parasitized erythrocytes. Low-flow inhaled nitric oxide (iNO) gas is a US FDA-approved treatment for hypoxic respiratory failure in neonates.

Methods/Design

This prospective, parallel arm, randomized, placebo-controlled, blinded clinical trial compares adjunctive continuous inhaled nitric oxide at 80 ppm to placebo (both arms receiving standard anti-malarial therapy), among Ugandan children aged 1-10 years of age with severe malaria. The primary endpoint is the longitudinal change in Ang-2, an objective and quantitative biomarker of malaria severity, which will be analysed using a mixed-effects linear model. Secondary endpoints include mortality, recovery time, parasite clearance and neurocognitive sequelae.

Discussion

Noteworthy aspects of this trial design include its efficient sample size supported by a computer simulation study to evaluate statistical power, meticulous attention to complex ethical issues in a cross-cultural setting, and innovative strategies for safety monitoring and blinding to treatment allocation in a resource-constrained setting in sub-Saharan Africa.

Trial Registration

ClinicalTrials.gov Identifier: NCT01255215     

Disruption of the mthfd1 gene reveals a monofunctional 10-formyltetrahydrofolate synthetase in mammalian mitochondria

The Mthfd1 gene encoding the cytoplasmic methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase enzyme (DCS) was inactivated in embryonic stem cells. The null embryonic stem cells were used to generate spontaneously immortalized fibroblast cell lines that exhibit the expected purine auxotrophy. Elimination of these cytoplasmic activities allowed for the accurate assessment of similar activities encoded by other genes in these cells. A low level of 10-formyltetrahydrofolate synthetase was detected and was shown to be localized to mitochondria. However, NADP-dependent methylenetetrahydrofolate dehydrogenase activity was not detected. Northern blot analysis suggests that a recently identified mitochondrial DCS (Prasannan, P., Pike, S., Peng, K., Shane, B., and Appling, D. R. (2003) J. Biol. Chem. 278, 43178-43187) is responsible for the synthetase activity. The lack of NADP-dependent dehydrogenase activity suggests that this RNA may encode a monofunctional synthetase. Moreover, examination of the primary structure of this novel protein revealed mutations in key residues required for dehydrogenase and cyclohydrolase activities. This monofunctional synthetase completes the pathway for the production of formate from formyltetrahydrofolate in the mitochondria in our model of mammalian one-carbon folate metabolism in embryonic and transformed cells.     

The distribution and evolutionary history of the PRP8 intein

Background  

We recently described a mini-intein in the PRP8 gene of a strain of the basidiomycete Cryptococcus neoformans, an important fungal pathogen of humans. This was the second described intein in the nuclear genome of any eukaryote; the first nuclear encoded intein was found in the VMA gene of several saccharomycete yeasts. The evolution of eukaryote inteins is not well understood. In this report we describe additional PRP8 inteins (bringing the total of these to over 20). We compare and contrast the phylogenetic distribution and evolutionary history of the PRP8 intein and the saccharomycete VMA intein, in order to derive a broader understanding of eukaryote intein evolution. It has been suggested that eukaryote inteins undergo horizontal transfer and the present analysis explores this proposal.     

Is it possible to develop pan-arthropod vaccines?

Hematophagous arthropods that transmit the etiological agents of arthropod-borne diseases have become the focus of anti-vector vaccines, targeted mainly at components of their saliva and midgut. These efforts have been directed mostly towards developing species-specific vaccines. An alternative is to target cross-reactive epitopes that have been preserved during evolution of the arthropods. The N- and O-linked glycans that are attached to arthropod glycoproteins are one of the potential targets of this pan-arthropod vaccine approach. Here, we discuss how genetically modified Drosophila melanogaster cells can be used to synthesize and to deliver these arthropod glycans to vertebrate hosts.     

Immunohistochemical and morphological features of a small bowel leiomyoma in a black crested macaque (Macaca nigra)

ABSTRACT: BACKGROUND: Spontaneous gastrointestinal neoplasms in non-human primates are commonly seen in aged individuals. Due to genetic similarities between human and non-human primates, scientists have shown increasing interest in terms of comparative oncology studies. CASE PRESENTATION: The present study is related to a case of an intestinal leiomyoma in a black crested macaque (Macaca nigra), kept on captivity by Matecana Zoo, Pereira City, Colombia. The animal had abdominal distension, anorexia, vomiting, diarrhea and behavioral changes. Clinical examination showed an increased volume in the upper right abdominal quadrant caused by a neoplastic mass. The patient died during the surgical procedure. Necropsy revealed several small nodules in the peritoneum with adhesion to different portions of the small and large intestines, liver, stomach and diaphragm. Tissue samples were collected, routinely processed and stained by H&E. Microscopic examination revealed a mesenchymal tumor limited to tunica muscularis, resembling normal smooth muscle cells. Neoplastic cells were positive for alpha-smooth muscle actin and vimentin, and negative for cytokeratin AE1/AE3 by immunohistochemistry. Those morphological and immunohistochemical findings allowed to diagnose the intestinal leiomyoma referred above. CONCLUSION: Neoplastic diseases in primates have multifaceted causes. Their manifestations are understudied, leading to a greater difficulty in detection and measurement of the real impact provides by this disease.     

Pangola grass colonized with Scytalidium thermophilum for production of Agaricus bisporus

This work had the dual objective of selecting a substrate for rapid mycelial growth of Scytalidium thermophilum and then comparing the growth and production of a brown variety of Agaricus bisporus on substrate non-colonized and colonized with S. thermophilum. Mycelial growth of S. thermophilum at 45 degrees C was significantly greater on potato dextrose yeast extract agar (0.58 mm/h) as compared to malt extract glucose agar (0.24 mm/h) and yeast extract glucose agar (0.44 mm/h). On cereal grain, S. thermophilum grew significantly faster on rice (0.31 mm/h) compared to sorghum (0.22 mm/h) and millet (0.18 mm/h). It also grew faster on Pangola grass (0.49 mm/h) compared to corncobs (0.30 mm/h) and sawdust (0.18 mm/h). Colonization of Pangola grass with S. thermophilum was influenced by the addition of calcium salts in the form of gypsum, hydrated lime and ground limestone. For production of A. bisporus, biological efficiency (BE) on pasteurized Pangola grass pre-colonized by S. thermophilum for 4 days at 45 degrees C was more than twice (26.4%) that on grass non-colonized by S. thermophilum (11.0%). The addition of 2% hydrated lime to Pangola grass prior to colonization by S. thermophilum resulted in an additional doubling of BE of mushroom production (48.1%). These results show the possibility of developing a non-composted substrate method for producing A. bisporus without autoclaving the substrate.     

Mice with endogenous TDP‐43 mutations exhibit gain of splicing function and characteristics of amyotrophic lateral sclerosis

TDP‐43 (encoded by the gene TARDBP) is an RNA binding protein central to the pathogenesis of amyotrophic lateral sclerosis (ALS). However, how TARDBP mutations trigger pathogenesis remains unknown. Here, we use novel mouse mutants carrying point mutations in endogenous Tardbp to dissect TDP‐43 function at physiological levels both in vitro and in vivo. Interestingly, we find that mutations within the C‐terminal domain of TDP‐43 lead to a gain of splicing function. Using two different strains, we are able to separate TDP‐43 loss‐ and gain‐of‐function effects. TDP‐43 gain‐of‐function effects in these mice reveal a novel category of splicing events controlled by TDP‐43, referred to as “skiptic” exons, in which skipping of constitutive exons causes changes in gene expression. In vivo, this gain‐of‐function mutation in endogenous Tardbp causes an adult‐onset neuromuscular phenotype accompanied by motor neuron loss and neurodegenerative changes. Furthermore, we have validated the splicing gain‐of‐function and skiptic exons in ALS patient‐derived cells. Our findings provide a novel pathogenic mechanism and highlight how TDP‐43 gain of function and loss of function affect RNA processing differently, suggesting they may act at different disease stages.     

Euphorbia cotinifolia (Euphorbiaceae): a promising alternative for leaf cutting ant Atta cephalotes (Hymenoptera: Formicidae) control

Field observations indicate that Euphorbia cotinifolia escapes attack by leaf cutting ants, which are the largest generalist herbivores of the Neotropics. We used controlled bioassays to evaluate the effect of E. cotinifolia on the foraging of the Atta cephalotes ant. In a free-choice trial, to five colonies were offered Mangifera indica leaves with a 10% aqueous E. cotinifolia extract, leaves with distilled water and untreated leaves. The carrying time and leaf area consumed were determined over a five-hour period. The effect of E. cotinifolia on the development of the symbiotic fungus on three sets of five colonies fed the leaves of this plant were compared to the controls fed M. indica and oat flakes, and the effect of the addition of extracts on the culture medium used for the symbiotic fungus isolation was evaluated. Euphorbia leaf consumption was lower than that of the other diets; its consumption as the exclusive foraging resource significantly affected the symbiotic fungus, resulting in changes in colour and texture and an 83.57% decrease in volume that occasionally caused 100% mortality. Although the aqueous extract of E. cotinifolia is not a phagodeterrent for foraging workers, it is evident that E. cotinifolia is not a preferred resource for A. cephalotes due to the negative effect on the growth and viability of the symbiotic fungus.