Divergent and point-to-point connections in the commissural pathway between the inferior colliculi

The commissure of the inferior colliculus interconnects the left and right sides of the auditory midbrain and provides the final opportunity for interaction between the two sides of the auditory pathway at the subcortical level. Although the functional properties of the commissure are beginning to be revealed, the topographical organization of its connections is unknown. A combination of neuroanatomical tracing studies, 3D reconstruction, and neuronal density maps was used to study the commissural connections in rat. The results demonstrate that commissural neurons in the central nucleus of the inferior colliculus send a divergent projection to the equivalent frequency-band laminae in the central nucleus and dorsal and lateral cortices on the opposite side. The density of this projection, however, is weighted toward a point that matches the position of the tracer injection; consistent with a point-to-point emphasis in the wiring pattern. In the dorsal cortex of the inferior colliculus there may be two populations of neurons that project across the commissure, one projecting exclusively to the frequency-band laminae in the central nucleus and the other projecting diffusely to the dorsal cortex. Neurons in the lateral cortex of the inferior colliculus make only a very weak contribution to the commissural pathway. The point-to-point pattern of connections permits interactions between specific regions of corresponding frequency-band laminae, whereas the divergent projection pattern could subserve integration across the lamina. J. Comp. Neurol. 514:226–239, 2009. © 2009 Wiley-Liss, Inc

7.1 T MRI to Assess the Anterior Segment of the Eye

PURPOSE. Visualization of the anterior segment and biometric evaluation of the entire crystalline lens pose significant challenges for imaging techniques because of tissue-induced distortion artifacts. The present study was conducted to demonstrate the advantages of high-resolution magnetic resonance imaging (micro-MRI) for visualizing the anterior segment. METHODS. High-resolution MR ocular images were acquired on an ultra-high-field MR unit using a two-channel coil with four coil elements and T(2)-weighted turbo spin echo sequences ex vivo in pig, rabbit, monkey, and human donor eyes and in vivo in rabbits. Tissue heating, reproducibility, and signal-to-noise ratio were investigated in vivo. Monkey eye lens thickness (LT) was also measured using A-scan ultrasonography (US). RESULTS. Anterior segment details of phakic eyes were obtained ex vivo (pig, rabbit, monkey, and human donor eyes) with pixel matrix size 512 x 512 (in-plane resolution 80 x 80 mu m) and in vivo (rabbit eyes) with pixel matrix size 320 x 320 (in-plane resolution 125 x 125 mu m). Complete quantification of lens dimensions as they correlate with the sulcus-sulcus and angle-angle plane can be performed. In LT determinations in monkey eyes, no significant difference was detected between micro-MRI and A-scan US (P > 0.05, Mann-Whitney U test). Biometric analysis of one pseudophakic monkey eye confirmed the absence of relevant distortion artifacts. CONCLUSIONS. Micro-MRI allows ex vivo and in vivo visualization and quantification of the spatial arrangement of the anterior eye segment. Imaging of the retroiridian region, including the entire crystalline lens, overcomes a number of major limitations in the quantitative evaluation of the anterior segment. (Invest Ophthalmol Vis Sci. 2010; 51: 6575-6581) DOI:10.1167/iovs.09-486

Infection Strategies Deployed by Botrytis cinerea, Fusarium acuminatum, and Rhizopus stolonifer as a Function of Tomato Fruit Ripening Stage

Worldwide, 20–25% of all harvested fruit and vegetables are lost annually in the field and throughout the postharvest supply chain due to rotting by fungal pathogens. Most postharvest pathogens exhibit necrotrophic or saprotrophic lifestyles, resulting in decomposition of the host tissues and loss of marketable commodities. Necrotrophic fungi can readily infect ripe fruit leading to the rapid establishment of disease symptoms. However, these pathogens generally fail to infect unripe fruit or remain quiescent until host conditions stimulate a successful infection. Previous research on infections of fruit has mainly been focused on the host’s genetic and physicochemical factors that inhibit or promote disease. Here, we investigated if fruit pathogens can modify their own infection strategies in response to the ripening stage of the host. To test this hypothesis, we profiled global gene expression of three fungal pathogens that display necrotrophic behavior—Botrytis cinerea, Fusarium acuminatum, and Rhizopus stolonifer—during interactions with unripe and ripe tomato fruit. We assembled and functionally annotated the transcriptomes of F. acuminatum and R. stolonifer as no genomic resources were available. Then, we conducted differential gene expression analysis to compare each pathogen during inoculations versus in vitro conditions. Through characterizing patterns of overrepresented pathogenicity and virulence functions (e.g., phytotoxin production, cell wall degradation, and proteolysis) among the differentially expressed genes, we were able to determine shared strategies among the three fungi during infections of compatible (ripe) and incompatible (unripe) fruit tissues. Though each pathogen’s strategy differed in the details, interactions with unripe fruit were commonly characterized by an emphasis on the degradation of cell wall components, particularly pectin, while colonization of ripe fruit featured more heavily redox processes, proteolysis, metabolism of simple sugars, and chitin biosynthesis. Furthermore, we determined that the three fungi were unable to infect fruit from the non-ripening (nor) tomato mutant, confirming that to cause disease, these pathogens require the host tissues to undergo specific ripening processes. By enabling a better understanding of fungal necrotrophic infection strategies, we move closer to generating accurate models of fruit diseases and the development of early detection tools and effective management strategies

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

The epidemiology of coronary heart disease : A review

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31999/1/0000041.pd