Blast-induced neurotrauma is a major concern because of the complex expression of neuropsychiatric disorders after exposure. Disruptions in neuronal function, proximal in time to blast exposure, may eventually contribute to the late emergence of clinical deficits. Using magic angle spinning ¹H MRS and a rodent model of blast-induced neurotrauma, we found acute (24-48 h) decreases in succinate, glutathione, glutamate, phosphorylethanolamine and γ-aminobutyric acid, no change in N-acetylaspartate and increased glycerophosphorylcholine, alterations consistent with mitochondrial distress, altered neurochemical transmission and increased membrane turnover. Increased levels of the apoptotic markers Bax and caspase-3 suggested active cell death, consistent with increased FluoroJade B staining in the hippocampus. Elevated levels of glial fibrillary acidic protein suggested ongoing inflammation without diffuse axonal injury measured by no change in β-amyloid precursor protein. In conclusion, blast-induced neurotrauma induces a metabolic cascade associated with neuronal loss in the hippocampus in the acute period following exposure.

Blast-induced neurotrauma (BINT) leads to deterioration at the cellular level, with adverse cognitive and behavioral outcomes. The nucleus accumbens (NAC) plays an important role in reward, addiction, aggression, and fear pathways. To identify the molecular changes and pathways affected at an acute stage in the NAC, this study focused on a time course analysis to determine the effects of blast on neurochemical and apoptotic pathways. By using a rodent model of BINT, acute damage to the NAC was assessed by proton magnetic resonance spectroscopy (¹H-MRS), high-performance liquid chromatography, immunohistochemistry, and Western blotting. The results demonstrated ongoing neuroprotective effects from elevated levels of Bcl-2, an antiapoptotic marker, at 24 hr and N-acetyl aspartate glutamate at 48 hr following blast exposure. Selective loss of serotonin levels at 24 hr, increased levels of inflammation (elevated glycerophosphocholine at 48 and 72 hr), and increased levels of glial fibrillary acidic protein were also observed at 24 and 48 hr, leading to disruptive energy status. Furthermore, active cell death was indicated by the increased levels of the apoptotic marker Bax, decreased actin levels, and signs excitotoxicity (glutamate/creatine). In addition, increased levels of caspase-3, an apoptotic marker, confirm active cell death in NAC. It is hypothesized that blast overpressure causes inflammation and neurochemical changes that trigger apoptosis in NAC. This cascade of events may lead to stress-related behavioral outcomes and psychiatric sequelae.

Objective: To practice evidence-based medicine, clinicians must be competent in information literacy (IL). Few studies acknowledge the critical role that reading strategies play in IL instruction and assessment of health professional students. The purpose of this study was to understand the information-seeking and evaluation behaviors of doctor of veterinary medicine (DVM) students in regard to scientific papers.Methods: The authors studied DVM student behaviors across eight programs in North America using a web-based survey of closed- and open-ended questions about finding and evaluating scientific papers, including a task to read a linked scientific paper and answer questions about it.Results: A total of 226 individuals responded to the survey. The sections of a scientific paper that were most commonly read were the abstract, introduction, and conclusions. Students who reported reading a higher proportion of scientific papers were more likely to feel confident in their abilities to interpret them. A third of respondents answered open-ended questions after the paper reading task. Respondents felt the least amount of confidence with one of the final steps of evidence-based medicine, that of interpreting the significance of the paper to apply it in veterinary medicine.Conclusions: DVM students may lack the skills needed to evaluate scientific literature and need more practice and feedback in evaluating and interpreting scientific papers. Librarians who support DVM students can (1) help DVM students to efficiently evaluate scientific literature, (2) seek training opportunities in alternative modes of teaching and learning IL skills, and (3) partner with veterinary faculty and clinicians to provide students with practice and feedback in information evaluation.

Orderly progression through meiosis requires strict regulation of DNA metabolic events, so that a single round of DNA replication is systematically followed by a recombination phase and 2 rounds of chromosome segregation. We report here the disruption of this sequence of events in Saccharomyces cerevisiae through meiosisspecific induction of the cyclin-dependent kinase (CDK) inhibitor Sic1 mutated at multiple phosphorylation sites. Accumulation of this stabilized version of Sic1 led to significant DNA rereplication in the absence of normal chromosome segregation. Deletion of DMC1 abolished DNA rereplication, but additional deletion of RAD17 restored the original phenotype. Therefore, activation of the meiotic recombination checkpoint, which arrests meiotic progression at pachytene, suppressed DNA rereplication resulting from Sic1 stabilization. In contrast to deletion of DMC1, deletion of NDT80, which encodes a transcription factor required for pachytene exit, did not inhibit DNA rereplication. Our results provide strong evidence that CDK activity is required to prevent inappropriate initiation of DNA synthesis before the meiotic divisions.checkpoint ͉ cyclin-dependent kinase ͉ premeiotic DNA replication ͉ recombination

Abscisic acid (ABA) is a plant hormone found in all higher plants; it plays an important role in seed dormancy, embryo development, and adaptation to environmental stresses, most notably drought. The regulatory step in ABA synthesis is the cleavage reaction of a 9-cis-epoxy-carotenoid catalyzed by the 9-cis-epoxy-carotenoid dioxygenases (NCEDs). The parasitic angiosperm Cuscuta reflexa lacks neoxanthin, one of the common precursors of ABA in all higher plants. Thus, is C. reflexa capable of synthesizing ABA, or does it acquire ABA from its host plants? Stem tips of C. reflexa were cultured in vitro and found to accumulate ABA in the absence of host plants. This demonstrates that this parasitic plant is capable of synthesizing ABA. Dehydration of detached stem tips caused a big rise in ABA content. During dehydration, 18 O was incorporated into ABA from 18 O 2 , indicating that ABA was synthesized de novo in C. reflexa. Two NCED genes, CrNCED1 and CrNCED2, were cloned from C. reflexa. Expression of CrNCEDs was up-regulated significantly by dehydration. In vitro enzyme assays with recombinant CrNCED1 protein showed that the protein is able to cleave both 9-cis-violaxanthin and 9#-cis-neoxanthin to give xanthoxin. Thus, despite the absence of neoxanthin in C. reflexa, the biochemical activity of CrNCED1 is similar to that of NCEDs from other higher plants. These results provide evidence for conservation of the ABA biosynthesis pathway among members of the plant kingdom.Abscisic acid (ABA) is found in all higher plants and algae and is also produced by some fungi (Oritani and Kiyota, 2003;Schwartz and Zeevaart, 2004;Nambara and Marion-Poll, 2005). In higher plants, ABA is involved in seed dormancy, embryo development, and adaptation to various abiotic stresses. ABA is a sesquiterpenoid (C 15 ). In some fungi, there is a direct pathway from isopentenyl pyrophosphate (C 5 ) via farnesyl pyrophosphate (C 15 ;Oritani and Kiyota, 2003). Higher plants synthesize ABA via the C 40 indirect pathway. A C 40 carotenoid is oxidatively cleaved to form a C 25 byproduct and the C 15 precursor of ABA, xanthoxin. Biochemical and molecular evidence has shown that the cleavage reaction is the rate-limiting step in the ABA biosynthetic pathway.Although the pathway of ABA biosynthesis in higher plants has been well established, there are still a few unresolved questions. One is the endogenous substrate of the cleavage reaction. The biochemical evidence has indicated that the C 40 substrate for production of biologically active ABA is an epoxy-carotenoid in the 9-cis configuration in order for biologically active ABA to be produced. In higher plants, the major 9-cis-epoxycarotenoids are 9#-cis-neoxanthin and 9-cis-violaxanthin. Because 9#-cis-neoxanthin is the most abundant 9-cisepoxy-carotenoid in higher plants, it has been speculated that 9#-cis-neoxanthin is the main endogenous substrate of ABA. However, in vitro enzyme assays with recombinant 9-cis-epoxy-carotenoid dioxygenase (NCED) proteins from several plant species have shown th...