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Muwazi L.,Makerere University | Rwenyonyi C.M.,Makerere University | Kutesa A.,Makerere University | Kasangaki A.,Makerere University | And 2 more authors.
Journal of Oral and Maxillofacial Pathology | Year: 2014

Conclusion: Although the 38-year period gave us sufficient numbers to use the Edward's method for seasonality, it also meant that a lot of seasonal changes that occurred during the period were not taken into consideration. We hence feel that a review of this data with weather experts, so as to group the biopsies into accurate rainfall and dry patterns, would yield a more authoritative publication.Results: Although monthly frequencies varied considerably over the period, none of the differences were statistically significant (Pearson's 15.199, degrees of freedom df = 11, P = 0.174). Likewise, there was no statistically significant difference in the total number of Burkitt's and nonspecific chronic inflammation biopsies handled at the Department during the rainy and dry seasons.Background/Aims: Burkitt's lymphoma is the most common childhood oral maxillofacial tumor in Africa and some studies have reported seasonal variation.Materials and Methods: All Burkitt's cases diagnosed from 1969 to 2006, from all over Uganda, at the Makerere University's Department of Pathology, were analyzed, to determine seasonal variation. This was done by evaluation of monthly and rainy versus dry season prevalence.Statistical analysis: The Wilcoxon test was used in both cases, to assess the statistical significance of differences in the diagnostic rates of Burkitt's lymphoma, in comparison to nonspecific chronic inflammation, using the total as the denominator. Yearly variation in prevalence was examined by a Chi-square test for linear trend. Mann-Whitney tests were done to compare the climatic regions. Multivariate analysis of variance (MANOVA) was used to test for differences when gender, seasons and climatic regions were factored in. Source


News Article
Site: http://phys.org/biology-news/

Naturally occurring proteins are the nanoscale machines that carry out nearly all the essential functions in living things. While it has been known for more than 40 years that a protein's sequence of amino acids determines its shape, it has been challenging for scientists to predict a protein's three-dimensional structure from its amino acid sequence. Conversely, it has been difficult for scientists to devise brand new amino acid sequences that fold up into hitherto unseen structures. A protein's structure dictates the types of biochemical and biological tasks it can perform. The Nature papers look at one type of natural construction: proteins formed of repeat copies of a structural component. The researchers examined the potential for creating new types of these proteins. Just as the manufacturing industry was revolutionized by interchangeable parts, originating protein molecules with the right twists, turns and connections for their modular assembly would be a bold direction for biotechnology. The papers are 'Exploring the repeat protein universe through computational design' and 'Rational design of alpha-helical tandem repeat proteins with closed architecture.' The findings suggest the possibilities for producing useful protein geometries that exceed what nature has achieved. The work was led by postdoctoral fellows TJ Brunette, Fabio Parmeggiani and Po-Ssu Huang in the lab of David Baker at the University of Washington Institute for Protein Design and Lindsey Doyle and Phil Bradley at the Fred Hutchinson Cancer Research Institute in Seattle. In addition, over the past several months, researchers at the Institute for Protein Design at the University of Washington, the Fred Hutch, and their colleagues at other institutions have described several other advances in two long-standing problem areas in building new proteins from scratch. "It has been a watershed year for protein structure predictions and design," said UW Medicine researcher David A. Baker, UW professor of biochemistry, Howard Hughes Medical Institute investigator, and head of the UW Institute for protein design. The protein structure problem is figuring out how a protein's chemical makeup predetermines its molecular structure, and in turn, its biological role. UW researchers have developed powerful algorithms to make unprecedented, accurate, blind predictions about the structure of large proteins of more than 200 amino acids in length. This has opened the door to predicting the structures for hundreds of thousands of recently discovered proteins in the ocean, soil, and gut microbiome. Equally difficult is designing amino acid sequences that will fold into brand new protein structures. Researchers have now shown the possibility of doing this with precision for protein folds inspired by naturally occurring proteins. More importantly, researchers can now devise amino acid sequences to fashion novel, previously unknown folds, far surpassing what is predicted to occur in the natural world. The new proteins are designed with help from volunteers around the globe participating in the Rosetta@home distributed computing project. The custom-designed amino acid sequences are encoded in synthetic genes, the proteins are produced in the laboratory, and their structures are revealed through X-ray crystallography. The computer models in almost all cases match the experimentally determined crystal structures with near atomic level accuracy. Researches have also reported new protein designs, all with near atomic level accuracy, for such shapes as barrels, sheets, rings and screws. This adds to previous achievements in designing protein cubes and spheres, and suggests the possibility of making a totally new class of protein materials. By furthering advances such as these, researchers hope to build proteins for critical tasks in medical, environmental and industrial arenas. Examples of their goals are nanoscale tools that: boost the immune response against HIV and other recalcitrant viruses, block the flu virus so that it cannot infect cells, target drugs to cancer cells while reducing side effects, stop allergens from causing symptoms, neutralize deposits, called amyloids, thought to damage vital tissues in Alzheimer's disease, mop up medications in the body as an antidote, and fulfill other diagnostic and therapeutic needs. Scientists are also interested in new proteins for biofuels and clean energy. In addition to this week's report on modular construction of proteins with repeating motifs, here are some other recent developments: Explore further: 'Digging up' 4-billion-year-old fossil protein structures to reveal how they evolved More information: TJ Brunette et al. Exploring the repeat protein universe through computational protein design, Nature (2015). DOI: 10.1038/nature16162 Lindsey Doyle et al, Rational design of α-helical tandem repeat proteins with closed architectures, Nature (2015). DOI: 10.1038/nature16191

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