Investigating a Possible Treatment of Duchene Muscular Dystrophy with a Novel Calpain Inhibitor [abstract]

Abstract only availableFaculty Mentor: Dr. Martin K. Childers, Physical Medicine & RehabilitationDuchene Muscular Dystrophy (DMD) is the most common lethal X-linked recessive muscle disease, affecting nearly one out of every 3,500 newborn males.  Symptoms appear before age three and by eleven, most children are unable to walk.  Few live past the age of 25.The genetic disorder is caused by a mutation in the dystrophin gene, eradicating the body's ability to produce the cytoskeletal protein, dystrophin.  In normal muscle cells, dystrophin is part of a molecular complex that adds mechanical integrity to the sarcolemma by linking the cytoskeleton to the extracellular matrix.  When the complex is disrupted, as in the case of DMD, the membrane is easily torn during regular muscle use.  Damage to the membrane causes aberrant influxes of Ca++, initiating a cascade of devastating molecular events in the sarcomere.  Elevated Ca++ over activates a family of proteases known as calpains. Calpains cleave proteins at specific sites.  Over-active calpains are thought to contribute to pathology in DMD.  Compounds that hinder calpain activity present a possible treatment for the disease.  A novel protease inhibitor has shown promising results in preliminary investigations in mice and this study was proposed to further explore the compound's effect on gene expression in canine muscle. An Affymetrix canine microarray was used to compare mRNA expression between normal dogs, dogs with golden retriever muscular dystrophy (GRMD), and inhibitor-treated GRMD dogs.  By comparing these expression levels, we are able to speculate whether calpain inhibitor treatment is able to mitigate aberrant gene expression in GRMD dogs.  Analysis of raw data is ongoing.  Further study is required to determine if mRNA levels equate with the protein expression levels using PCR, Western Blotting, or other methods

Postal recruitment for genetic studies of preterm birth: A feasibility study.

Background: Preterm birth (PTB) represents the leading cause of neonatal death. Large-scale genetic studies are necessary to determine genetic influences on PTB risk, but prospective cohort studies are expensive and time-consuming. We investigated the feasibility of retrospective recruitment of post-partum women for efficient collection of genetic samples, with self-collected saliva for DNA extraction from themselves and their babies, alongside self-recollection of pregnancy and birth details to phenotype PTB. Methods: 708 women who had participated in the OPPTIMUM trial (a randomised trial of progesterone pessaries to prevent PTB [ISRCTN14568373]) and consented to further contact were invited to provide self-collected saliva from themselves and their babies. DNA was extracted from Oragene OG-500 (adults) and OG-575 (babies) saliva kits and the yield measured by Qubit. Samples were analysed using a panel of Taqman single nucleotide polymorphism (SNP) assays. A questionnaire designed to meet the minimum data set required for phenotyping PTB was included. Questionnaire responses were transcribed and analysed for concordance with prospective trial data using Cohen's kappa ( k). Results: Recruitment rate was 162/708 (23%) for self-collected saliva samples and 157/708 (22%) for questionnaire responses. 161 samples from the mother provided DNA with median yield 59.0µg (0.4-148.9µg). 156 samples were successfully genotyped (96.9%). 136 baby samples had a median yield 11.5µg (0.1-102.7µg); two samples failed DNA extraction. 131 baby samples (96.3%) were successfully genotyped. Concordance between self-recalled birth details and prospective birth details was excellent ( k>0.75) in 4 out of 10 key fields for phenotyping PTB (mode of delivery, labour onset, ethnicity and maternal age at birth). Conclusion: This feasibility study demonstrates that self-collected DNA samples from mothers and babies were sufficient for genetic analysis but yields were variable. Self-recollection of pregnancy and birth details was inadequate for accurately phenotyping PTB, highlighting the need for alternative strategies for investigating genetic links with PTB

Hubble Space Telescope Images of Stephan's Quintet: Star Cluster Formation in a Compact Group Environment

Analysis of Hubble Space Telescope/Wide Field Planetary Camera 2 images of Stephan's Quintet, Hickson Compact Group 92, yielded 115 candidate star clusters (with V-I < 1.5). Unlike in merger remants, the cluster candidates in Stephan's Quintet are not clustered in the inner regions of the galaxies; they are spread over the debris and surrounding area. Specifically, these sources are located in the long sweeping tail and spiral arms of NGC 7319, in the tidal debris of NGC 7318B/A, and in the intragroup starburst region north of these galaxies. Analysis of the colors of the clusters indicates several distinct epochs of star formation that appear to trace the complex history of dynamical interactions in this compact group.Comment: 24 pages, 21 figures (13 PostScript and 8 JPEG), LaTeX (uses aastexug.sty), accepted for publication in the Astronomical Journal (July 2001). Full-resolution PostScript figures available at http://www.astro.psu.edu/users/gallsc/sq/figs.tar.g

Hydrologic and isotopic modeling of Alpine Lake Waiau, Mauna Kea, Hawai'i

Analysis of hydrologic, meteorologic, and isotopic data collected over 3 yr quantifies and explains the enormous variability and isotopic enrichment (δ18O = +16.9, δD = +50.0) of alpine Lake Waiau, a culturally and ecologically significant perched lake near the summit of Mauna Kea, Hawai'i. Further, a simple one-dimensional hydrologic model was developed that couples standard water budget modeling with modeling of δD and δ18O isotopic composition to provide daily predictions of lake volume and chemistry. Data analysis and modeling show that winter storms are the primary source of water for the lake, adding a distinctively light isotopic signature appropriate for high-altitude precipitation. Evaporation at the windy, dry summit is the primary loss mechanism for most of the year, greatly enriching the lake in heavy isotopes

The American Association for the Surgery of Trauma renal injury grading scale: Implications of the 2018 revisions for injury reclassification and predicting bleeding interventions.

BackgroundIn 2018, the American Association for the Surgery of Trauma (AAST) published revisions to the renal injury grading system to reflect the increased reliance on computed tomography scans and non-operative management of high-grade renal trauma (HGRT). We aimed to evaluate how these revisions will change the grading of HGRT and if it outperforms the original 1989 grading in predicting bleeding control interventions.MethodsData on HGRT were collected from 14 Level-1 trauma centers from 2014 to 2017. Patients with initial computed tomography scans were included. Two radiologists reviewed the scans to regrade the injuries according to the 1989 and 2018 AAST grading systems. Descriptive statistics were used to assess grade reclassifications. Mixed-effect multivariable logistic regression was used to measure the predictive ability of each grading system. The areas under the curves were compared.ResultsOf the 322 injuries included, 27.0% were upgraded, 3.4% were downgraded, and 69.5% remained unchanged. Of the injuries graded as III or lower using the 1989 AAST, 33.5% were upgraded to grade IV using the 2018 AAST. Of the grade V injuries, 58.8% were downgraded using the 2018 AAST. There was no statistically significant difference in the overall areas under the curves between the 2018 and 1989 AAST grading system for predicting bleeding interventions (0.72 vs. 0.68, p = 0.34).ConclusionAbout one third of the injuries previously classified as grade III will be upgraded to grade IV using the 2018 AAST, which adds to the heterogeneity of grade IV injuries. Although the 2018 AAST grading provides more anatomic details on injury patterns and includes important radiologic findings, it did not outperform the 1989 AAST grading in predicting bleeding interventions.Level of evidencePrognostic and Epidemiological Study, level III

Atypical Case Of Wolfram Syndrome Revealed Through Targeted Exome Sequencing In A Patient With Suspected Mitochondrial Disease

Background: Mitochondrial diseases comprise a diverse set of clinical disorders that affect multiple organ systems with varying severity and age of onset. Due to their clinical and genetic heterogeneity, these diseases are difficult to diagnose. We have developed a targeted exome sequencing approach to improve our ability to properly diagnose mitochondrial diseases and apply it here to an individual patient. Our method targets mitochondrial DNA (mtDNA) and the exons of 1,600 nuclear genes involved in mitochondrial biology or Mendelian disorders with multi-system phenotypes, thereby allowing for simultaneous evaluation of multiple disease loci. Case Presentation: Targeted exome sequencing was performed on a patient initially suspected to have a mitochondrial disorder. The patient presented with diabetes mellitus, diffuse brain atrophy, autonomic neuropathy, optic nerve atrophy, and a severe amnestic syndrome. Further work-up revealed multiple heteroplasmic mtDNA deletions as well as profound thiamine deficiency without a clear nutritional cause. Targeted exome sequencing revealed a homozygous c.1672C > T (p.R558C) missense mutation in exon 8 of WFS1 that has previously been reported in a patient with Wolfram syndrome. Conclusion: This case demonstrates how clinical application of next-generation sequencing technology can enhance the diagnosis of patients suspected to have rare genetic disorders. Furthermore, the finding of unexplained thiamine deficiency in a patient with Wolfram syndrome suggests a potential link between WFS1 biology and thiamine metabolism that has implications for the clinical management of Wolfram syndrome patients

From Globular Clusters to Tidal Dwarfs: Structure Formation in the Tidal Tails of Merging Galaxies

Using V and I images obtained with WFPC2/HST, we investigate compact stellar structures within tidal tails. Six regions of tidal debris in the four classic ``Toomre Sequence'' mergers: NGC 4038/39 (``Antennae''), NGC 3256, NGC 3921, and NGC 7252 (``Atoms for Peace'') have been studied in order to explore how the star formation depends upon the local and global physical conditions. These mergers sample a range of stages in the evolutionary sequence and tails with and without embedded tidal dwarf galaxies. The six tails are found to contain a variety of stellar structures, with sizes ranging from those of globular clusters up to those of dwarf galaxies. From V and I WFPC2 images, we measure the luminosities and colors of the star clusters. NGC 3256 is found to have a large population of blue clusters (0.2 < V-I < 0.9), particularly in its Western tail, similar to those found in the inner region of the merger. In contrast, NGC 4038/39 has no clusters in the observed region of the tail, only less luminous point sources likely to be individual stars. A significant cluster population is clearly associated with the prominent tidal dwarf candidates in the eastern and western tails of NGC 7252. The cluster-rich Western tail of NGC 3256 is not distinguished from the others by its dynamical age or by its total HI mass. However, the mergers that have few clusters in the tail all have tidal dwarf galaxies, while NGC 3256 does not have prominent tidal dwarfs. We speculate that star formation in tidal tails may manifest itself either in small structures like clusters along the tail or in large structures such as dwarf galaxies, but not in both. Also, NGC 3256 has the highest star formation rate of the four mergers studied, which may contribute to the high number of star clusters in its tidal tails.Comment: Accepted to Astronomical Journal. 34 pages including 15 figures and 4 table

Effect of rhPDGF-BB on bone turnover during periodontal repair

Purpose : Growth factors such as platelet-derived growth factor (PDGF) exert potent effects on wound healing including the regeneration of periodontia. Pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) is a well-known biomarker of bone turnover, and as such is a potential indicator of osseous metabolic activity. The objective of this study was to evaluate the release of the ICTP into the periodontal wound fluid (WF) following periodontal reconstructive surgery using local delivery of highly purified recombinant human PDGF (rhPDGF)-BB. Methods : Forty-seven human subjects at five treatment centres possessing chronic severe periodontal disease were monitored longitudinally for 24 weeks following PDGF regenerative surgical treatment. Severe periodontal osseous defects were divided into one of three groups and treated at the time of surgery with either: Β -tricalcium phosphate (TCP) osteoconductive scaffold alone (active control), Β -TCP+0.3 mg/ml of rhPDGF-BB, or Β -TCP+1.0 mg/ml of rhPDGF-BB. WF was harvested and analysed for local ICTP levels by radioimmunoassay. Statistical analysis was performed using analysis of variance and an area under the curve analysis (AUC). Results : The 0.3 and 1.0 mg/ml PDGF-BB treatment groups demonstrated increases in the amount of ICTP released locally for up to 6 weeks. There were statistically significant differences at the week 6 time point between Β -TCP carrier alone group versus 0.3 mg/ml PDGF-BB group ( p <0.05) and between Β -TCP alone versus the 1.0 mg/ml PDGF-BB-treated lesions ( p <0.03). The AUC analysis revealed no statistical differences amongst groups. Conclusion : This study corroborates the release of ICTP as a measure of active bone turnover following local delivery of PDGF-BB to periodontal osseous defects. The amount of ICTP released from the WF revealed an early increase for all treatment groups. Data from this study suggests that when PDGF-BB is delivered to promote periodontal tissue engineering of tooth-supporting osseous defects, there is a direct effect on ICTP released from the wound.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72239/1/j.1600-051X.2005.00870.x.pd

Sexual Communication Between Early Adolescents and Their Dating Partners, Parents, and Best Friends

This study assessed early adolescents' sexual communication with dating partners, parents, and best friends about six sexual health topics: condoms, birth control, STDs, HIV/AIDS, pregnancy, and abstinence/waiting. Using a school-based sample of 603 youth (ages = 12–15; 57% female; 46% Caucasian), we examined communication differences across demographic and developmental factors, tested whether communication with parents and best friends was associated with greater communication with partners, and examined associations between communication and condom use. Over half of participants had not discussed any sexual topics with their dating partners (54%), and many had not communicated with parents (29%) or best friends (25%). On average, communication was more frequent among adolescents who were female, African American, older, and sexually active, despite some variation in subgroups across partner, parent, and friend communication. Importantly, communication with parents and friends – and the interaction between parent and friend communication – was associated with increased communication with dating partners. Further, among sexually active youth, increased sexual communication with partners was associated with more frequent condom use. Results highlight the importance of understanding the broader family and peer context surrounding adolescent sexual decision-making and suggest a possible need to tailor sexual communication interventions