143 research outputs found
Air embolism as a cause of the systemic inflammatory response syndrome: a case report
We describe a case of systemic inflammatory response syndrome associated with air embolism following the removal of a central line catheter, coupled with a deep inspiratory maneuver. The presence of a patent foramen ovale allowed the passage of a clinically significant amount of air from the venous circulation to the systemic circulation. The interaction of air with the systemic arterial endothelium may have triggered the release of endothelium-derived cytokines, resulting in the physiologic response of systemic inflammatory response syndrome
Dynein/dynactin regulate metaphase spindle length by targeting depolymerizing activities to spindle poles
During cell division metaphase spindles maintain constant length, whereas spindle microtubules continuously flux polewards, requiring addition of tubulin subunits at microtubule plus-ends, polewards translocation of the microtubule lattice, and removal of tubulin subunits from microtubule minus-ends near spindle poles. How these processes are coordinated is unknown. Here, we show that dynein/dynactin, a multi-subunit microtubule minus-end–directed motor complex, and NuMA, a microtubule cross-linker, regulate spindle length. Fluorescent speckle microscopy reveals that dynactin or NuMA inhibition suppresses microtubule disassembly at spindle poles without affecting polewards microtubule sliding. The observed uncoupling of these two components of flux indicates that microtubule depolymerization is not required for the microtubule transport associated with polewards flux. Inhibition of Kif2a, a KinI kinesin known to depolymerize microtubules in vitro, results in increased spindle microtubule length. We find that dynein/dynactin contribute to the targeting of Kif2a to spindle poles, suggesting a model in which dynein/dynactin regulate spindle length and coordinate flux by maintaining microtubule depolymerizing activities at spindle poles
Current Status and Future Perspective on Enzyme Involving in Biocontrol of Plant Pathogen
Plant diseases must be controlled to maintain the quality and quantity of food produced by farmers worldwide. Various strategies exist to prevent, reduce, or manage plant diseases. Agronomic and horticultural methods depend on chemical fertilisers and insecticides. These agricultural inputs have contributed significantly to recent gains in crop output and quality. Microbial enzymes help bacteria multiply in a specific habitat by acting as biocatalysts for biochemical processes. It has long been recognised that rhizosphere microorganisms may boost plant development and suppress phytopathogens. Rhizosphere microorganisms may help plants fight phytopathogens in numerous ways. Excreting lytic enzymes is one of the acknowledged biocontrol methods for preventing phytopathogens from surviving in the rhizosphere. To combat phytopathogens, rhizosphere microbes create chitinases, cellulases, proteases, and glucanases. Biological management may soon replace fungicides, say UBC researchers. New molecular approaches are now available to study antagonist-pathogen interactions, rhizosphere antagonist ecology, and biocontrol agent efficacy. Because agro-ecosystems are dynamic structures with numerous factors affecting disease and crop productivity, alternative IPM strategies to manage crop diseases are useful in various environments. Diverse crop systems need IPM management options other than biological control to successfully prevent disease development and yield loss
Three-dimensional acoustic scattering from arctic ice proturberances.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1995.Includes bibliographical references (leaves 191-196).Ph.D
Searching for the middle ground: mechanisms of chromosome alignment during mitosis
The contributions of key molecules predicted to align chromosomes at the center of the mitotic spindle have been recently examined. New results dictate that models for how chromosomes align during the early stages of mitosis must be revised to integrate properties of microtubule-based motor proteins as well as microtubule dynamics
Eg5 is static in bipolar spindles relative to tubulin: evidence for a static spindle matrix
We used fluorescent speckle microscopy to probe the dynamics of the mitotic kinesin Eg5 in Xenopus extract spindles, and compared them to microtubule dynamics. We found significant populations of Eg5 that were static over several seconds while microtubules flux towards spindle poles. Eg5 dynamics are frozen by adenylimidodiphosphate. Bulk turnover experiments showed that Eg5 can exchange between the spindle and the extract with a half life of <55 s. Eg5 distribution in spindles was not perturbed by inhibition of its motor activity with monastrol, but was perturbed by inhibition of dynactin with p50 dynamitin. We interpret these data as revealing the existence of a static spindle matrix that promotes Eg5 targeting to spindles, and transient immobilization of Eg5 within spindles. We discuss alternative interpretations of the Eg5 dynamics we observe, ideas for the biochemical nature of a spindle matrix, and implications for Eg5 function
Snakebite presenting as acute coronary syndrome: An interesting diagnosis and management
Snakebite is a common presentation in India, especially in the Sub-Himalayan region. The most common presentation of snakebiteis neurotoxic and hematologic complications. Acute coronary syndrome after a snakebite is rare. This case report explicitly explainsa patient presenting as acute coronary syndrome after a snakebite with dynamic electrocardiogram changes. Later on, the anti-snakevenom therapy was given to the patient and her condition improved. It should be kept in mind that, since the pathology of snakebiteinducedmyocardial infarction is different, its management will also be different
Marking and Measuring Single Microtubules by PRC1 and Kinesin-4
SummaryError-free cell division depends on the assembly of the spindle midzone, a specialized array of overlapping microtubules that emerges between segregating chromosomes during anaphase. The molecular mechanisms by which a subset of dynamic microtubules from the metaphase spindle are selected and organized into a stable midzone array are poorly understood. Here, we show using in vitro reconstitution assays that PRC1 and kinesin-4, two microtubule-associated proteins required for midzone assembly, can tag microtubule plus ends. Remarkably, the size of these tags is proportional to filament length. We determine the crystal structure of the PRC1 homodimer and map the protein-protein interactions needed for tagging microtubule ends. Importantly, length-dependent microtubule plus-end-tagging by PRC1 is also observed in dividing cells. Our findings suggest how biochemically similar microtubules can be differentially marked, based on length, for selective regulation during the formation of specialized arrays, such as those required for cytokinesis
Minus-end capture of preformed kinetochore fibers contributes to spindle morphogenesis
Near-simultaneous three-dimensional fluorescence/differential interference contrast microscopy was used to follow the behavior of microtubules and chromosomes in living α-tubulin/GFP-expressing cells after inhibition of the mitotic kinesin Eg5 with monastrol. Kinetochore fibers (K-fibers) were frequently observed forming in association with chromosomes both during monastrol treatment and after monastrol removal. Surprisingly, these K-fibers were oriented away from, and not directly connected to, centrosomes and incorporated into the spindle by the sliding of their distal ends toward centrosomes via a NuMA-dependent mechanism. Similar preformed K-fibers were also observed during spindle formation in untreated cells. In addition, upon monastrol removal, centrosomes established a transient chromosome-free bipolar array whose orientation specified the axis along which chromosomes segregated. We propose that the capture and incorporation of preformed K-fibers complements the microtubule plus-end capture mechanism and contributes to spindle formation in vertebrates
Lymphocytic hypophysitis masquerading as transient secondary hyperadrenalism followed by panhypopituitarism
Lymphocytic hypophysitis (LH) is a rare inflammatory disease of the pituitary gland. This condition strikingly shows femalepreponderance and commonly affects women during pregnancy or in the post-partum period. It’s a clinical presentation and radiologicalfeatures may mimic pituitary adenoma. Though its treatment modality is uncertain steroid remains the 1st option for treatment. Here,we report an unusual case of LHin a 21-year-old female patient where initially, the patient presented with hyperadrenalism andsecondary hyperthyroidism followed by pan-hypopituitarism (Addisonian crisis) which is attributed to initial autoimmune destructionof the gland followed by subsequent fibrosis. Thus, it is a rare case report which exquisitely explains this rare presentation and suchcases should be investigated thoroughly since there are many differential and response to steroids is remarkable
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