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Biomedical subjects

Augusto Rendon

Publications and source records attributed to Augusto Rendon.

3 recordsLinked to original sources

The Biobank Rare Variant consortium powers the discovery of rare genetic associations through global collaboration.

Rare coding variants can have large effects on disease risk and provide direct routes from human genetics to disease mechanisms and therapeutic targets, but their discovery is constrained by sample size, particularly for low-prevalence diseases. Here we establish the Biobank Rare Variant Analysis (BRaVa) consortium, a global rare variant association resource that integrates sequencing and linked health-record data from ten biobanks and cohorts comprising over 1.2 million individuals across diverse ancestries. We performed gene-based meta-analyses of rare coding variation across 33 clinical endpoints and 11 quantitative traits. Aggregating evidence across biobanks and ancestries identified 514 gene-trait associations, including 31 not previously reported in prior studies or curated association resources following systematic literature review. Notably, 36.1% of gene-level associations were undetectable in any individual biobank, and 91 emerged only through cross-ancestry meta-analysis, demonstrating that federated integration enables discovery beyond the reach of single cohorts. Similar gains were observed at the variant level, where 25.0% of phenotype-locus associations were detectable only through meta-analysis. Effect size estimates were correlated across ancestries with concordant directions of effect, supporting the generalizability of rare variant associations. The identified signals implicate pathways involved in transcriptional and epigenetic regulation, metabolism, vascular and epithelial biology, and immune function, highlighting rare coding variation as an engine for biological discovery across medical record phenotypes. For example, damaging variation in ANKRD12 implicates inflammatory transcriptional dysregulation in asthma and chronic obstructive pulmonary disease, and ultra-rare predicted loss-of-function variants in NAA15 link protein acetylation processes to type 2 diabetes risk. BRaVa establishes a scalable framework and freely available community resource for rare variant meta-analysis across global biobanks. Public release of gene- and variant-level association summary statistics provides a reference map of rare coding variant associations to support disease gene discovery, biological interpretation, and therapeutic target prioritization as sequencing-linked health-record resources continue to expand.

Journal Article↗

Towards conformal light delivery using tailored cylindrical diffusers: attainable light dose distributions.

Interstitial light delivery for therapeutic applications requires the use of fibre-based light diffusers. Such diffusers are presently manufactured to emit with a flat longitudinal power profile. Recently, diffusers with tailored longitudinal emission profiles have become available opening an avenue to improve conformal light delivery. This paper explores the ability of tailored diffusers to improve light dose confinement to the target volume. A formalism to calculate the light dose from an arbitrary source distribution is presented based on the convolution with an appropriate point source function. By choosing a source distribution corresponding to a cylindrical diffuser emitting with a sinusoidal profile, the set of attainable light dose distributions is characterized via a relationship between the diffuser's spatial frequency, the radial distance and the amplitude of the isodose contour.

Biophysical Phenomena↗

The distribution of the anticancer drug Doxorubicin in relation to blood vessels in solid tumors.

PURPOSE: Anticancer drugs gain access to solid tumors via the circulatory system and must penetrate the tissue to kill cancer cells. Here, we study the distribution of doxorubicin in relation to blood vessels and regions of hypoxia in solid tumors of mice. EXPERIMENTAL DESIGN: The distribution of doxorubicin was quantified by immunofluorescence in relation to blood vessels (recognized by CD31) of murine 16C and EMT6 tumors and human prostate cancer PC-3 xenografts. Hypoxic regions were identified by injection of EF5. RESULTS: The concentration of doxorubicin decreases exponentially with distance from tumor blood vessels, decreasing to half its perivascular concentration at a distance of about 40 to 50 mum, The mean distance from blood vessels to regions of hypoxia is 90 to 140 microm in these tumors. Many viable tumor cells are not exposed to detectable concentrations of drug following a single injection. CONCLUSIONS: Limited distribution of doxorubicin in solid tumors is an important and neglected cause of clinical resistance that is amenable to modification. The technique described here can be adapted to studying the distribution of other drugs within solid tumors and the effect of strategies to modify their distribution.

Animals↗