bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between human milk oligosaccharides and fecal microbiome of breastfed infants
Authors: Williams Janet E , Riley Mara A , Brooker Sarah L , Hunt Katherine M , Szyszka Alexandra , Bode Lars , McGuire Michelle K , McGuire Mark A
Published: June 2021

Human milk oligosaccharides (HMO) have been shown to impact growth of staphylococci and bifidobacteria in vitro. However, little is known as to whether amounts of HMO consumed by infants are related to the composition of their gastrointestinal (GI) microbiomes. To examine this, milk and infant fecal samples were collected from mother/infant dyads (n = 12) on d 2, 5, 10, 30 and 60 after birth. DNA was extracted, the 16S rRNA gene amplified, and relative microbial abundance characterized by 454 pyrosequencing. HMO concentrations were determined using HPLC. Spearman's correlation coefficients were calculated to relate HMO concentration with relative abundance of fecal bacterial genera and diversity indices at each time point. On d2, Streptococcus abundance was negatively correlated (r = −0.94) with 2′fucosyllactose (2′FL); Lactococcus, Leuconostoc, and Weissella abundances were correlated (r = 0.98, 0.92, and 0.93, respectively) with disialyllacto‐N‐tetraose (DSLNT). On d10, Bacteroides abundance was correlated (r = 0.73) with 2′FL. On d2, DSLNT correlated (r = 0.88) with the Chao richness index. Results suggest possible associations between HMO and presence of some microbial genera, but relationships were not consistent over time. Supported by the Bill and Melinda Gates Foundation and the Institute for Bioinformatics and Evolutionary Studies (IBEST).
Dietary Fat Composition Modifies Cell Sphingolipid Biosynthesis to Mediate the consequences of obesity.
Authors: Cowart L. Ashley
Published: June 2021

Obesity is associated with type 2 diabetes, non‐alcoholic fatty liver disease, and cardiovascular disease, but mechanisms by which obesity may promote these disease states are not fully understood. We demonstrate that in obesity, dietary fat composition is reflected in plasma lipid profiles, and differential lipid supply to cells profoundly impacts the biosynthesis of bioactive sphingolipids including ceramides and sphingosine‐1‐phosphate, which mouse obesity models indicate mediate obesity‐induced disease. We have used these models as well as cultured cells to identify specific pathways of sphingolipid metabolism that underlie obesity‐induced diseases including non‐alcoholic fatty liver disease and diabetic cardiomyopathy. Specifically, data demonstrated that Ceramide Synthase 5 regulated cardiac myocyte autophagy and subsequent hypertrophy, and our data also suggest roles for sphingosine kinase 1 in mediating inflammatory processes associated with obesity. We propose that these pathways constitute novel therapeutic targets for obesity‐associated disease.
ATP utilization by DExD/H‐box RNA helicases – molecular motor proteins that couple ATPase activity with RNA rearrangement.
Authors: De La Cruz Enrique M
Published: June 2021

DExD/H‐box proteins (DBPs) utilize the free energy associated with ATPase cycling to perform work on RNA substrates. DBPs are found across all phyla, from RNA viruses to humans, and have evolved biological roles throughout RNA metabolism involving RNA unwinding, rearrangement of (mis)folded RNAs, and/or disruption of RNA‐protein complexes. DBPs share several highly conserved structural motifs that couple ATPase and RNA rearrangement activities. However, enzymatic adaptations alter the rate and equilibrium constants of the ATPase cycle, which affect both the efficiency and processivity of these enzymes. We have investigated the ATP utilization mechanisms of DBPs involved in bacterial rRNA folding, eukaryotic mRNA splicing, and RNA virus replication. The partially rate‐limiting formation of the DBP‐ADP‐ Pi intermediate on RNA is a likely candidate for the dominant force‐producing transition of the RNA‐activated DBP ATPase cycle. This step precedes ATP‐dependent duplex RNA strand dissociation during non‐processive unwinding. Evaluation of ATP utilization during processive RNA translocation requires parsing of initiation, stepping and dissociation. These studies reveal enzymatic features associated with ATPase coupling to RNA rearrangement and processive translocation by different DBP classes. An NSF CAREER Award (MCB‐0546353) supported this research.
mTOR Complex 1, Metabolism and Cell Growth Control
Authors: Blenis John , Csibi Alfredo , Kim Sang Gyun , Gu Xiaoxiao , Li Jeannie , Buel Gwen , Lee Gina , Jang Young Jin
Published: June 2021

Mutations in the TSC1 or TSC2 genes are responsible for causing Tuberous Sclerosis Complex (TSC) and Lymphangioleiomyomatosis (LAM). These mutations lead to the uncontrolled activation of the mTOR complex 1 (mTORC1), a cellular protein kinase complex that regulates metabolism, autophagy and cell growth. Cells with TSC1/2 mutations require increased energy and carbon sources to meet their high metabolic needs for cell growth. To meet this demand, we have found that activated mTORC1 uses distinct mechanisms to increase glutamine consumption (glutaminolysis) by elevating the expression of glutaminase and the activity of glutamate dehydrogenase. Furthermore, TSC mutant cells sense the increased energy production and in a positive feedback loop, promote more mTORC1 assembly via an AMP kinase (AMPK)‐dependent, and a novel AMPK‐independent mechanism. This acquired addiction to glutamine provides a novel therapeutic strategy for treating patients with activated mTORC1. Indeed, by acutely blocking the ability of TSC‐mutant cells to use glutamine, we are able to selectively kill cells with mutations in TSC1 or TSC2 without damaging normal cells. We anticipate that these studies will lead to the development of “synthetic‐lethal” drugs useful in the treatment of cancers with inappropriate regulation of mTORC1.
Capturing transient transcriptional activator‐coactivator complexes with large and small molecules
Authors: Mapp Anna K
Published: June 2021

Most essential cellular functions are accomplished by dynamic macromolecular assemblies comprised of least one enzyme component surrounded by non‐enzymatic moieties that enforce the timing, location and specificity of the complex function. In the case of transcription, transcriptional activators direct the assembly of the RNA polymerase II holoenzyme at specific gene promoters at particular time points; once the polymerase is engaged, the complex disassembles as transcription initiates. This is accomplished through protein‐protein interactions (PPIs) that are dynamic and, in some cases, short‐lived. Despite their prevalence and functional importance, these PPIs are historically all but impossible for small molecule modulation and are typically classified as ‘undruggable’. The challenge is multi‐variable: the binding partners often have significant disorder and are thus difficult to characterize structurally alone or in complex; the surface area of the area of the interactions are considerably larger than protein‐ligand interactions, and the strengths of the interactions are modest. Two distinct classes of modulators of coactivator‐activator complexes will be discussed, with applications in the covalent capture and characterization of the complexes as well as modulation of assemblies in the context of head and neck squamous cell carcinoma.
Effects of leucine and adipocyte derived microparticles on human peripheral blood monocyte CD11b expression
Authors: Curry Benjamin , Biggerstaff John , Zemel Michael B
Published: June 2021

We previously demonstrated that calcitriol and leucine modulate adipocyte cytokine production, with corresponding effects on monocyte‐vascular endothelial cell adhesion in vitro and ex vivo and on monocyte CD11b and endothelial cell ICAM‐1 expression. Recent evidence suggests that adipocyte derived microparticles (ADMs) may serve as a messenger system between adipose tissue and peripheral blood. Therefore, we tested the hypothesis that ADMs isolated from leucine treatment of 3T3‐L1 adipocytes will reduce monocyte CD11b expression in fresh human blood. 3T3‐L1 cultures were treated with vehicle (control) or 0.5 mM leucine for 48 hrs and the conditioned media (CM) was collected. ADMs were isolated by ultracentrifugation and samples of CM, supernatant fraction, and ADM fraction were incubated with fresh whole blood for 2 and 18 hrs. Monocyte CD11b expression was assessed using flow cytometry and results are presented as the percent of monocytes positive for CD11b ± SEM. After 2 hrs, monocyte CD11b+ decreased from 68.6 ± 3.4% (control) to 47.7 ± 7.6% in the presence of leucine CM, and the leucine ADMs recapitulated this effect. Similarly, leucine ADMs reduced monocyte CD11b+ from 72.1 ± 4.0% (control) to 48.4 ± 2.7% (p <0.05) following 18‐hr incubation. These results suggest that leucine treatment of adipocytes reduces CD11b expression on fresh human monocytes and that ADMs mediate some of these effects.
Nutrition & Health Elective for First Year Medical Students
Authors: Mossavar‐Rahmani Yasmin , Reznik Marina , Barnhart Janice , Davis Nichola , Kligler Benjamin , Burton William
Published: June 2021

Objective

We describe a six session elective on Nutrition and Health for first year medical students at the Albert Einstein College of Medicine that combines nutrition content with a motivational interviewing‐based approach to interact with patients.

Methods

Sessions were developed with student input and facilitated by a nutritionist and physicians. Topics consisted of: Nutrition Assessment; Science behind USDA Nutrition Recommendations; Dispelling Myths about Dieting; Motivational Interviewing; Reading Nutrition Facts Label and Hot Topics in Nutrition. In the first session students also assessed their percent body fat using a Tanita scale. For the nutrition facts session students paired up with patients with limited English speaking ability and used an elicit‐provide‐elicit approach to assist patients with reading labels.

Data for the 2011–2012 classes are presented. A total of 28 students participated (N=24 with complete data). Pre‐ and post‐multiple choice knowledge test consisting of 13 questions indicated an average increase of 2.68 points on all test items, (p<0.0001). High attendance (>; 86% for each class yr) and student ratings (4.2 for course facilitation & content from a scale of 1= poor to 5=excellent) attest to the engagement of students.

Conclusions

A nutrition elective that combines the art and science of nutrition engages students and improves their knowledge of nutrition.
Pituitary homeobox 2 (PITX2) protects renal cancer cell lines against doxorubicin toxicity by transcriptional activation of the multidrug transporter ABCB1
Authors: Lee Wing‐Kee , Chakraborty Prabir Kumar , Thévenod Frank
Published: June 2021

The multidrug resistance (MDR) P‐glycoprotein ABCB1 plays a major role in MDR of malignant cells and is regulated by various transcription factors, including Wnt/β‐catenin/TCF4. The transcription factor PITX2 (Pituitary homeobox‐2) is essential for embryonic development. PITX2 operates by recruiting and interacting with β‐catenin to increase the expression of growth‐regulating genes, such as cyclin D1/2 and c‐Myc. The importance of PITX2 in malignancy is not yet known. Here, in the renal cancer cell lines ACHN and A498, ABCB1 expression correlates with nuclear PITX2 localization and PITX2‐luciferase reporter gene activity (A498 >; ACHN). PITX2 overexpression increases ABCB1 expression and cell survival in ACHN cells. Silencing of PITX2 by siRNA down‐regulates ABCB1 and induces a greater chemotherapeutic response to doxorubicin in A498 cells, as determined by MTT cell viability and clonogenic survival assays. Two PITX2 binding sequences were identified in the ABCB1 promoter sequence. PITX2 binding was confirmed by chromatin immunoprecipitation. Beta‐catenin is not required for PITX2 upregulation of ABCB1 since ABCB1 mRNA increased and doxorubicin toxicity decreased upon PITX2 overexpression in β‐ catenin−/− cells. The data show for the first time that ABCB1 is a target gene of PITX2 transcriptional activity, promoting MDR and cell survival. Funded by DFG and Westermann‐Westdorp Foundation, Germany.
Aromatase Inhibitor Resistance in Breast Cancer: a Potential Role for Cytokine Signaling Network.
Authors: Barone Ines , Gelsomino Luca , Giordano Cinzia , Lanzino Marilena , Bonofiglio Daniela , Fuqua Suzanne AW , Catalano Stefania , Andò Sebastiano
Published: June 2021

Background

Resistance to aromatase inhibitors (AIs) is frequently acquired with an associated poor prognosis. Breast cancer models revealed the importance of growth factor signals in sustaining endocrine‐resistant growth; however it remains unknown the potential of cytokine networks in creating a microenvironment supporting tumor progression.

Methods

MCF‐7 aromatase‐overexpressing breast cancer cells (WT) and their AI anastrozole‐resistant (AnaR) counterparts were generated. Human Cancer Associated Fibroblasts (CAFs) as stromal cells. Realtime PCR for cytokine changes, immunoblotting analysis for signaling activation, MTT and soft agar assays for growth were used.

Results

AnaR cells exhibited elevated phosphorylation of MAPK, but not of PI3K/Akt signaling pathways. AnaR cells expressed high levels of IL‐1, IL‐6, leptin and their receptors and also showed an increased proliferation after treatment with these cytokines. Conditioned medium (CM) from CAFs was more effective in stimulating growth of AnaR compared to WT cells, and Ana treatment reversed these effects only in WT cells. Inhibition of the cytokine JAK2/STAT3 cascade suppressed CM‐induced proliferation in AnaR cells.

Conclusions

Acquired AI resistance was accompanied by development of a cytokine‐driven phenotype, highlighting the potential clinical benefit of targeting cytokine networks in hormone‐resistant breast cancers.
Clinical Case Studies Increase the Level of Neuropharmacology Education for PharmD Students
Authors: Rahman Shafiqur
Published: June 2021

Neuropharmacology course is required for PharmD students in Pharmacy curriculum. In this course, students follow standard pharmacology text books, with minimal coverage of basic or clinical neuroscience. Extensive knowledge of drugs that are used for treatment of neuropsychiatric disorders, their adverse effects and interactions are very important to pharmacy profession. The present study has investigated how to improve the level of neuropharmacology education for PharmD students by using clinical cases studies relevant to therapeutic management of neuropsychiatric disorders. The results showed a significant difference in student performance before and after adding these clinical case studies. Overall, this study suggests that addition of clinical case studies which show the effects of drugs and adverse effects on improved PharmD students’ performance and comprehension in studying neuropharmacology course.
Team‐taught grand rounds promote horizontal and vertical integration in a discipline‐based medical curriculum
Authors: Duffourc Michelle Marie , Schoborg Robert V. , McGowen K. Ramsey , Lybrand Cynthia , Blackwelder Reid B.
Published: June 2021

Discipline‐based medical curricula face the challenges of promoting horizontal (across course) and vertical (across years) integration, as well as providing opportunities for students to build the skills needed to become “residents‐as‐teachers”. To address these issues, we developed an Integrated Grand Rounds (IGR) series in which cases are co‐presented to M1/M2 students by clinical and basic science faculty. Sub‐topics relevant to the case are expanded upon by means of live patient interviews and small group sessions led by M3/M4 students. IGR effectiveness is measured by comparison of pre‐/post‐test scores and student attitude questionnaires.

Overall, student post‐test scores improved by 23% and >; 95% of all students felt that this activity was an effective way to both integrate information across courses and highlight clinical applications of basic science material. Additionally, all M3/M4 students polled felt that the IGR provided a valuable opportunity to review important basic science concepts and practice clinical teaching skills.

The IGR series has proven to be a highly successful tool for cross‐course and longitudinal integration and is enthusiastically supported by both faculty and students. Notably, the IGR provides an efficient and cost‐effective vehicle to expand interdisciplinary connections and enhance integration. As a result, we are in the process of expanding its use in our curriculum.
Teaching of 2nd year medical school autonomic pharmacology in simulated shock experiences
Authors: Gorman A. Laurel , Gros Bernard , Cendan Juan
Published: June 2021

To develop an innovative method for teaching autonomic pharmacology, we incorporated sympathomimetic treatments into simulated shock sessions. Effective teaching of autonomic pharmacology is essential to provide the background and critical thinking skills necessary to understand cardiovascular concepts. Since students previously struggled with autonomic pharmacology didactics, innovative teaching methods that stress application and clinical relevance were developed to improve learning. Thus, pharmacology was incorporated into both cardiogenic and septic shock simulations developed with SimMan manikins during the 2nd year cardiovascular module. Sympathomimetic choices in the simulations were: epinephrine, dobutamine, phenylephrine, norepinephrine, dopamine, and albuterol. Non‐sympathomimetic choices were also included. Multi‐disciplinary debriefings performed immediately after the simulations focused on integrated clinical and pharmacology teaching. Students had positive perceptions of the simulations, describing them as an “awesome” and “unforgettable” way to learn pharmacology. Preliminary formative and summative assessment data suggested an improvement in autonomic pharmacology performance. Thus, sympathomimetic pharmacology was effectively and innovatively taught in two simulations with manikins suffering from septic and cardiogenic shock, respectively.
Important techniques in today's biomedical science research that African PhD candidates should be exposed to: a perspective from the FASEB Journal
Authors: John Theresa Adebola
Published: June 2021

The need for best evidence for profitable research has necessitated multidisciplinary, collaborative approaches which are mainstay in today's biomedical science (BS). For African PhD graduates in basic medical sciences to better profit from research, they need multidisciplinary approaches to research during their subject‐based training. The present report sought to substantiate this. Thirty three published articles in the April 2012 FASEB journal were studied for the methods employed. The papers utilized an average of 9 major BS techniques, 9 being the mean, median, and mode showing the global status quo of diversity of methodology per scientific paper. The most popular procedures and techniques recorded in more than 1/3 of the articles were: cell isolation; cell culture; in vivo or in situ whole animal studies; animal models of disease; gene/protein expression, sequencing and cloning; transfection, constructs, and genomic interference and silencing; western blotting; fluorescence and confocal microscopy; ELISAs and cell‐based assays; and ready‐made biotech assay kits. The most popular statistics were various student's t‐tests at 0.05 confidence levels and ANOVAs. The GraphPad Prism was the most frequently used statistic software. These methods are therefore recommended to be included in Ph.D. training.
STEM & Health: Stressors on the circulatory system
Authors: Cooper Robin L , Krall Rebecca McNall , Cooper Hyewon , Mayo Susan , Johnson Diane , Zeidler‐Watters Kim , Rose Stephanie
Published: June 2021

The goal of these exercises is to understand the circulatory system while integrating STEM and health‐related issues. For high and middle school students the ability to assembly a model from a provided kit to represent the human circulatory system and relate the physics of how pressures are altered due to health related issues (obesity, arteriosclerosis) should promote the importance of why a healthy life style is advantageous. The hope is that providing cardiovascular kits to classrooms for teachers to use will bridge biology, physics and health concepts for an integrative approach to learning within STEM related around fluid dynamics and physiology. Four kits represent: (1) plaque formation and effect on flow, (2) elastic recoil and arteriosclerosis, (3) effects of blood viscosity, (4) differential blood pressure related to resistance. Since new national standards in teaching for secondary teachers in life sciences are to cover “modeling” as engineering and design, this activity is timely and very suited for a life science classroom for high & middle schools as well as college level. In the four activities (kits), the alteration in the extant of circulatory “tubing” to flow and the effect of resistance on blood pressure can be modeled and experimented with by inquiry learning. Funded by KY Department of Education Science Leadership Support Network.
Enamel use wear of small carnivores: effects of magnification and scale
Authors: Dewar Eric Walter , Elder Carley E. , Le Thuy , Sharma Prashant
Published: June 2021

Living carnivorans have dietary preferences from strictly carnivorous and to broadly herbivorous diets. Some of the details of these diets are not predictable from dental morphology alone. We compared the enamel use wear of living carnivorans with a variety of known diets using stereoscopic and scanning electron microscopy (SEM). We developed a systematic description of enamel wear on the same specimens at a range of magnifications from 35× and 75× on the stereoscope to 150×, 250×, and 500× on the SEM. Both microscopes and a range of magnifications were able to resolve differences among dietary types. Stereoscopic observations of carnivoran teeth revealed roughly similar counts of wear features despite the differences in sampling area. Using the SEM, differences in the appearance of wear is more apparent, particularly in number and depth of enamel scratches. We found that divergent microwear within species represented meal‐to‐meal vs. seasonally‐variable styles of omnivory. We expect that some species of mustelids (skunks and other weasels) and small canids (especially foxes) can be used as a baseline against which we can compare the wear of several species of the earliest Carnivora from the Eocene.
Shape Analysis of the Facebase 3D Facial Norms Dataset Reveals Sexual Dimorphism in Human Faces in Juveniles, Adolescents and Adults
Authors: Parsons Trish Elizabeth , Raffensperger Zachary D , Hecht Jacqueline T , Heike Carrie L , Cunningham Michael L , Marazita Mary L , Weinberg Seth Michael
Published: June 2021

One of the major goals of the 3D Facial Norms Project is to create a large publically available database of 3D facial images and measurements from healthy human subjects. This dataset provides an unparalleled opportunity for the study of human facial shape. The current sample size of almost 1,000 subjects allows us to immediately address questions on a range of topics, including sexual dimorphism and changes over the lifespan. Anthropologists have long known that the human facial shape is sexually dimorphic; our question is: when does facial sexual dimorphism present itself during ontogeny? We broke our sample into three age groups, 19–40 (n = 722), 11–18 (n = 90) and 3–10 (n = 119). These groups represent roughly before, during and after puberty. We hypothesize that facial differences between the sexes would first emerge in the 11–18 group and become more divergent in the 19 – 40 group. Shape was assessed using geometric morphometrics. The results indicate that sexual dimorphism is detectable even in the youngest group (Procrustes distance (P‐dist) between male and female mean shapes: 0.0148, p = 0.017). The means shapes are also different between males and females among the 11–18 age group (P‐dist = 0.0208, p < 0.0001) and the difference is largest in the adult sample (P‐dist = 0.0215, p < 0.0001). These results have implications on our understanding of the drivers of sexual dimorphism in human faces.

Grant Funding Source: This work was supported by NIH Grant number 1U01DE020078 to SMW
Imaging Interactions Between Transferrin‐containing Endosomes and Mitochondria
Authors: Das Anupam , Nag Sagarika , Barroso Margarida
Published: June 2021

Iron transport occurs via iron binding to transferrin (Tfn), which is then taken up by the Tfn‐receptor (TFR) at the plasma membrane and delivered to endosomes, where upon acidification Tfn undergoes iron release. Iron is then transported to the mitochondria via a yet unknown mechanism; in the mitochondria, iron is incorporated into the heme groups of proteins involved in cellular respiration. The “kiss and run” hypothesis states that iron is transported into the mitochondria via a direct interaction between endosomes and mitochondria. To test the “kiss and run” hypothesis in epithelial cells, we will use time‐lapse live‐cell fluorescence TIRF microscopy to assay the colocalization of endosomes and mitochondria under various conditions that affect pH and Tfn‐iron binding capacity. Our goal is to develop a semi‐automated image analysis protocol based on the Imaris software to characterize putative “kiss and run” events. Our analysis shows that endosomal speed increases before the “kiss” as well as before the “run” of each “kiss and run” event. During the attachment period the endosome reduces its motility. We have developed an image analysis protocol that provides both qualitative and quantitative information on putative kiss and run events between endosomes and mitochondria, allowing us in the future to assay them functionally and ascertain their dependency on Tfn's iron binding ability as well as endocytic pH.
The Impact Of Different Additives To Neutral Buffered Formalin
Authors: Hewitt Stephen Merrill , Perry Candice D , Ylaya Kris , Morris Jennifer , Chung Joon‐Yong
Published: June 2021

Background

Neutral Buffered Formalin (NBF) is the industry standard fixative for anatomic pathology. In addition to 105 formaldehyde, NBF contains up to 10% methanol as well as buffering agents. In addition to NBF, different reagents can be added in an effort to improve the quality of proteins and nucleic acids isolated from formalin fixed, paraffin embedded tissue.

Methods

Tissue was fixed individually in different fixative formulations to evaluate the contribution of each reagentt in the fixative. Tissues were subsequently paraffin embedded. Endpoint analysis included evaluation of cyto‐and histo‐morphology, immunohistochemistry, and RNA quality.

Results

The addition of phosphate buffer contributes to the greatest improvement in quality, at the RNA level compared to other ingredients and additives in neutral buffered formalin.

Conclusions

The presence or absence of other reagents in neutral buffered formalin has limited impact on biomolecule quality in the presence of appropriate buffers.
Discordance between skeletal and dental age at time of death in a western lowland gorilla (Gorilla gorilla gorilla)
Authors: Joganic Jessica Lynn , Cheverud James M
Published: June 2021

A young adult male western lowland gorilla died of accidental causes at the St. Louis Zoo in 2010. Necropsy results indicate he was in good health with no injuries or illnesses. His skeleton was macerated and examination revealed developmental anomalies. Although his chronological age was ~9 years, partial fusion of the capitulum and trochlea to his left humerus and the olecranon process to his right ulna were the only instances of postcranial epiphyseal union, indicating a gorilla of Stage I. However, with mandibular M3 in full occlusion, maxillary M3 near occlusion, and canines still erupting, his dental age is Stage IV. We compare his skeletal dimensions to those published and find he is of average size. His behavior and appearance were similar to that of his conspecifics. Possible causes of delayed skeletal maturation include disorders increasing growth hormone, decreasing testosterone, or altering connective tissue composition. Although dental and skeletal maturation are usually correlated, they are able to proceed in a discordant fashion. This case‐study highlights: (1) the fact that the dentition and skeleton are under separate but related physiological and genetic controls and (2) the importance of relying on multiple lines of evidence when aging unknown individuals. We acknowledge the provision of skeletal material and life history records by Ingrid Porton and the veterinary staff of the St. Louis Zoo.
The LIM Homeodomain Transcription Factor Lhx6: A Transcriptional Repressor that Interacts with Pituitary Homeobox 2 (PITX2) to Regulate Odontogenesis
Authors: Amendt Brad A. , Zhang Zichao , Gutierrez Diana , Li Xiao , Bidlack Felicitas , Cao Huojun , Wang Jianbo , Margolis Henry C
Published: June 2021

Lhx6 is a LIM‐homeobox transcription factor expressed during embryogenesis, however the molecular mechanisms regulating Lhx6 transcriptional activities are unknown. Lhx6 expression is increased in Pitx2c transgenic mice and decreased in Pitx2 null mice. PITX2 activates endogenous Lhx6 expression and the Lhx6 promoter while Lhx6 represses its promoter activity. Chromatin immunoprecipiation experiments reveal endogenous Pitx2 binding to the Lhx6 promoter. Lhx6 directly interacts with PITX2 to inhibit PITX2 transcriptional activities and activation of multiple promoters. Bimolecular fluorescence complementation assays reveal an Lhx6‐Pitx2 nuclear interaction in living cells. Lhx6 has a dominant repressive effect on the PITX2 synergistic activation with Lef‐1 and β‐catenin co‐factors. Thus, Lhx6 acts as a transcriptional repressor and we have identified specific defects in incisor, molar, mandible, bone and root development and late stage enamel formation in Lhx6 null mice. Our results demonstrate that Lhx6 regulates cell proliferation in the cervical loop and promotes cell differentiation in the anterior region of the incisor. We demonstrate new molecular mechanisms for Lhx6 and an interaction with PITX2 for normal craniofacial and tooth development. Support for this research was provided from grants DE13941 and DE18885 from the National Institute of Dental and Craniofacial Research.
Mechanisms for differential endocytosis of CD44 involved in turnover and signaling in chondrocytes
Authors: Askew Emily Blair , Hida Daisuke , Ono Yohei , Knudson Cheryl B. , Knudson Warren
Published: June 2021

In cartilage, hyaluronan (HA) is anchored to chondrocytes via binding to CD44. We have shown that CD44‐mediated endocytosis and lysosomal degradation of HA requires CD44 palmitoylation and subsequent transit into lipid raft microdomains. Interestingly, raft‐CD44 is also a substrate for MMP cleavage generating a 20kD C‐terminal fragment. In chondrocytes, CD44‐HA complexes are thought to be present in different membrane pools, some destined for endocytosis and others involved in signaling, migration or anchorage of matrix. Differentiating these pools is challenging due in part to the constant replenishment of CD44. Trypsin treatment of chondrocytes generates a unique 25kD fragment representative of CD44 present in all membrane pools prior to typsinization; the 20kD fragment only the lipid raft pool. Decay of both 20 and 25kD CD44 fragments is completely blocked by chloroquine suggesting lysosomal degradation as a common endpoint. No 20kD domains were derived from 25kD fragments suggesting the 25kD cannot subsequently move into lipid rafts and serve as a substrate for MMP and γ‐secretase. Chlorpromazine, 350 mM sucrose and Dynasore, inhibitors of clathrin coated vesicle formation, partially block the decay of the 25kD fragment. We hypothesize that raft‐CD44 is responsible for HA endocytosis; whereas CD44 involved in signaling may be downregulated by clathrin‐associated endocytosis. Supported by NIH R01‐AR39507 and R01‐AR43384.

Grant Funding Source: NIH R01‐AR39507 and R01‐AR43384
The enteropathogenic E. coli receptor Tir remains non‐ubiquitylated to enable the bacteria to remain extracellular
Authors: Guttman Julian Andrew , Lin Ann E.
Published: June 2021

Cells use clathrin‐mediated endocytosis as one strategy to internalize particles from the extracellular compartment. This mechanism of internalization requires the use of a ligand and receptor for the internalization event to occur. Recent work suggests that in order for large particles to enter non‐phagocytic cells their receptors must become ubiquitylated. Ubiquitylation involves the posttranslational modification of a protein by ubiquitin. Enteropathogenic E. coli (EPEC) is an extracellular microbe that injects its own receptor, called the translocated intimin receptor (Tir), into epithelial cells. Surprisingly clathrin‐associated components are recruited to the site of EPEC/host cell contact, but somehow clathrin's internalization function is blocked. We hypothesized that the EPEC receptor Tir remains non‐ubiquitylated to ensure that EPEC remains extracellular. To test this hypothesis we used immunoprecipitations and western blotting of EPEC infected epithelial cells to examine the ubiquitylation status of EPEC Tir and found that it does not become ubiquitylated. To functionally test our hypothesis we forced EPEC Tir to be ubiquitylated by directly fusing ubiquitin to EPEC Tir. This fusion was transfected into epithelial cells and the cells infected with EPEC containing a non‐functional Tir, resulting in the bacteria being internalized. Our work demonstrates that during normal EPEC infections, the blockage of Tir receptor ubiquitylation contributes to EPEC remaining extracellular.
Bridging integrator protein 3 (Bin3) deletion causes cataract due to morphological abnormalities in lens cells
Authors: Scheiblin David A , Duncan Melinda K
Published: June 2021

The lens is a complex epithelial tissue whose highly organized structure is required for its transparency. The BAR superfamily of peripheral membrane proteins control membrane curvature in many contexts and deletion of the BAR family member, Bin3, from mice results in cataracts (a clouding of the lens) associated with actin defects. However, the role that Bin3 plays in postnatal lens development and homeostasis is not known.

Hematoxylin and Eosin staining of Bin3 null lenses revealed minor defects in fiber cell packing from birth to 3 weeks postnatal. The defects in fiber cell packing became progressively worse from 1 month until the fiber cells exhibited both vacuoles and disrupted fiber cell packing by 2 months. Scanning electron micrographs show that the elaborate membrane protrusions found on normal lens fiber cells becomes disorganized in Bin3 null lenses. The observed actin defects along with the morphological defect lead us to hypothesize that Bin3 is important for actin nucleation along lens fiber cell lateral membranes. Multiple proteins such as Cdc42, N‐WASP, and ARP2/3 control actin nucleation. In yeast Bin3 recruits Cdc42 to the cell division site and facilitates its activation, thus changing the cytoskeleton. It has not been shown whether this process is conserved in mammalian cells. Current studies suggest that Cdc42 plays a role in changing the cytoskeleton in Bin3 null lenses.

Funded by NEI EY12221.

Grant Funding Source: NEI EY 12221
Muscle‐derived cells (MDCs) responsible for myogenesis differ from MDCs involved in adipogenesis in dystrophin/utrophin−/− mice
Authors: Sohn Jihee , Lu Aiping , Tang Ying , Wang Bing , Huard Johnny
Published: June 2021

Ectopic fat formation/accumulation and infiltration in skeletal muscle is closely associated with several disorders including Duchenne muscular dystrophy (DMD), a degenerative muscle disorder. However, neither the origin of ectopic adipocytes, nor the mechanism of their formation in disease, is known. Based on a previously published preplate technique, we isolated two types of muscle derived cells; rapidly adhering cells (RACs) and slowly adhering cells (SACs) from skeletal muscle of C57BL (wt) and utrophin/dystrophin double knockout (dys−/−utro−/−, dKO) mice, which emulates the phenotype seen in DMD patients. Previously, we have shown that SACs are myogenic progenitor cells and are mainly involved in muscle fiber regeneration or degeneration. Here, we identify RACs as PDGFRá + multipotent, mesenchymal progenitor cells and observe that dKO‐RACs display increased adipogenic, osteogenic, and chondrogenic potentials compared to wt‐RACs. We also show that, compared to other muscle‐derived cell populations from dKO mice, RACs display significantly increased proliferation and adipogenic potentials both in vitro and in vivo. This study suggests that RACs may be the major contributor to ectopic fat cell formation within skeletal muscle in pathological conditions such as DMD. Therefore, targeting RACs to block adipogenesis in skeletal muscle may open new opportunities to treat muscle diseases.

Grant Funding Source: Department of Defense (DOD) – Army
Superficial subscapular artery: Incidence in the Black South African Population
Authors: Xhakaza Nkosiphendule K. , Naidu Jesse S. , Satyapal Kapil S.
Published: June 2021

The subscapular artery, the largest branch of the axillary artery, usually arises from the third part of the axillary artery at the inferior border of subscapularis muscle. Approximately 4cm from its origin it divides into the circumflex scapular and thoracodorsal arteries. Separate origins of its terminal branches have been referred to as an absent subscapular artery. Yamada (1967) distinguished two types of subscapular artery: the first one arose from the axillary artery proximal to the point where the axillary artery passed between the lateral and medial roots of median nerve and the second type arose distal to this point. Yamada (1967) referred to the former as the superficial subscapular artery(SSA) and the later as the deep subscapular artery (DSA). This study aims to determine the incidence of SSA in the South African black population. The study comprised of bilateral dissections of 50 adult black South African cadavers (n = 100 axillary arteries). The site of origin of each vessel was recorded. Additional branches and variations were also noted. SSA was found in 47% cases. In 31.9% cases, it was bilateral. DSA was found in 42%. In 15%, subscapular artery gave rise to the posterior circumflex humeral artery; lateral thoracic artery in 30%, and to upper subscapular artery in 36% cases. It was absent in 11%. The literature review records this incidence to range between 0–16% in the following population groups: Japanese, Indians, Whites and Negroes which differ significantly to this study. The results of this study may have clinical significance as a superficial course of arteries make them vulnerable to injury during surgical procedures.
Variant Distribution of the Obtuse Marginal Artery of the Heart (Anatomical and Multislice CT Imaging)
Authors: El‐Maasarany Shirley Hilal Labib , El‐Tahhan Salah Mohammed , Beiram Dalia Mahmoud
Published: June 2021

Background

The obtuse marginal artery (OMA) is one or two branches from the left circumflex branch(LCx) of the left main coronary artery (LMCA). It supplies the most lateral wall of the left ventricle.

Aim

The aim of the present work was to study the origin, size, distribution and variations of the OMA.

Material and Methods

Twenty embalmed human hearts showing no gross pathological lesions in the wall of the chambers were used. The LMCA, the left anterior descending(LAD), the LCX and the OMA were dissected to study their distribution. Multislice Computed Tomography (MSCT) of forty healthy individuals with no obstructed lesions were studied retrospectively.

Results

Gigantic OMA was seen in 3 out of the 20 dissected specimens and in 5 out of the 40 MSCT hearts. Its diameter was bigger than the LCx itself (more than 3.4 mm in diameter). They supply not only the lateral wall of the left ventricle but also most of its anterior and inferior walls reaching to the apex.

Conclusion

These variant anatomical findings shoud be considered during various interventional and surgical procedures.
Acute blood pressure response to exercise in post‐menopausal women
Authors: Bentley Danielle Christine , Thomas Scott G
Published: June 2021

Chronic blood pressure (BP) reductions resulting from exercise interventions have been linked to an acute vascular response, post‐exercise hypotension (PEH). PEH has traditionally been stimulated using continuous aerobic exercise bouts. The use of isometric handgrip (IHG) contractions to elicit PEH is an emerging area. The present research investigated PEH in response to both ergometer cycling and bilateral IHG contractions in post‐menopausal women, a demographic of imperative concern. Women completed an acclimatization session followed by four experimental sessions; two using IHG as a stimulus and two using ergometer cycling as a stimulus. Pre‐ and post‐exercise BP were determined using an automated sphygmomanometer (BPTru). Participants were 5 post‐menopausal women with an average resting BP of 117.8 ± 1.8 / 79.9 ± 1.7. In contrast to expectation, both of the exercise stimuli induced acute increases in BP. Aerobic stimuli induced increases of 2.1 ± 0.6 / 3.2 ± 0.4. IHG stimuli induced changes of 3.9 ± 0.7 / 3.9 ± 0.5. Further exploration of this relationship is required to determine the exercise protocols which will elicit PEH in this specific population of post‐menopausal women. This information will be valuable in prescribing acute exercise bouts for blood pressure control in this at‐risk demographic. This research was completed with support from the Dr. Terry Kavanagh Research Fellowship.

Grant Funding Source: CIHR
Over‐Expression of Cancer Testis Antigen Genes in Multiple Myeloma Stem Cell‐like Cells
Authors: Wen Jianguo , Savoldo Barbara , Zu Youli , Chang Chung‐Che
Published: June 2021

Multiple myeloma (MM) stem cells, proposed to be responsible for the tumorigenesis, drug resistance and recurrence are enriched in the side population (SP) cells. Cancer testis antigens (CTAs) are attractive targets for immunotherapy since they are widely expressed in cancers but only in limited types of normal tissues. We designed the high throughput real‐time PCR assay allowing simultaneously relative quantifying expression of 90 CTA genes associated with MM. We firstly analyzed the CTA genes expression profile in SP cells of MM cell lines: RPMI8226, MM1S, and U266. In comparison with mature plasma cells (MPCs), 16, 13, and 11 CTA genes were up‐regulated in SP of abovementioned 3 cell lines respectively. 6 CTA genes have overlap in 2 of 3 cell lines, and genes LUZP4 and ODF1 are universally up‐regulated in all 3 MM cell lines. Subsequently, primary bone marrow (BM) from 8 MM patients and 4 healthy donors were studied, and we found that 19 CTA genes were up‐regulated in SP cells of MM BM compared with their MPCs. Notably, expression level of 6 CTA genes were increased in SP cells of both MM BM and at least 1 MM cell line. In contrast, only 2 CTA genes had moderate increase in SP cells of healthy BM compared with their MPCs. Our findings indicates that multiple CTAs are highly expressed in SP cells of both MM cell lines and patient's BM, suggesting potential molecular targets for immunotherapy and other targeted therapy specific for MM.
Susceptibility of multiple myeloma stem cells and their progeny to NK‐cell mediated cytotoxicity
Authors: Podberezin Mark , Wen Jianguo , Chang Jeff
Published: June 2021

Background

The purpose of our study was to examine sensitivity of MM cells and their SC progenitors (which are characterized by negativity for CD138 and active efflux of Hoechst 33342 dye) to natural killer (NK)‐cell mediated cytotoxicity.

Methods

NK cells were generated from peripheral blood mononuclear cells of healthy volunteers and co‐cultured with MM (RPMI 8226) cells for 4 hours. NK cell cytotoxicity was assessed by flow cytometry assay. Three different NK/target cell ratios were used. MMSC represented by side population (SP) (negative for Hoechst and CD138) were quantified as percentage of total viable MM cells.

Results

NK cells exhibited significant cytotoxicity against RPMI 8226 cells in all three ratios. Surprisingly, the strongest cytotoxicity was demonstrated when minimal NK/MM ratio (2.5:1) was used. We hypothesize that this phenomenon could be due to NK‐NK cell fratricide. Remarkably, proportion of the overall viable target cell population, represented by MMSC, decreased.

Conclusions

MM cells are sensitive to NK‐mediated cytotoxicity. The finding of major importance was potential susceptibility of MMSC to NK‐cell mediated cytotoxicity which could make NK cells additive armamentarium in treating minimal residual disease in patients with MM.
MAGNETIC RESONANCE AND BIOLUMINESCENCE IMAGING MONITOR QUANTITATIVE DIFFERENCES IN PANCREATIC ISLETS AND THEIR REGENERATION AFTER BETA CELL LOSS
Authors: Meda Paolo , Lamprianou Smaragda , Lei Honxia , Vinet Laurent , Gruetter Rolf , Montet Xavier
Published: June 2021

Many questions about the natural history of diabetes remain unanswered, since it is not yet possible to repeatedly image pancreatic islets in vivo. We evaluated whether manganese‐enhanced MRI (MEMRI) could be useful in this context. Using a 14.1T equipment, we found that MEMRI visualizes individual islets, and ex vivo quantitates their different mass in control and diabetic mice. Using a 1.5T equipment, we repeatedly monitored transgenic mice, after deletion of their insulin‐producing beta cells by diphtheria toxin. The pancreatic signal, reporting on beta cell mass, decreased in all animals exposed to the toxin. This decrease was 66% and 33% in male and female mice, respectively, paralleling the gender difference in insulin and islet content. As evaluated by bioluminescence, the pancreas signal remained unchanged, with insulin content, in diabetic males for more than a year. In contrast, these parameters progressively returned to control levels in a subset of normoglycemic females. In a retrospective clinical study, we found that MEMRI increased the pancreas signal of both normoglycemic and type 2 diabetic patients, due to high uptake by the endocrine islets. However, this enhancement was 30% lower in the latter than in the former group of patients (p < 0.01), consistent with the decrease in beta cell mass indicated by pathology. The data show that MEMRI quantitatively detects pancreatic islets, evaluates their changes in models of experimental diabetes, and could be translatable into a clinical context.
Eliminating the need for multiple injections during a dental procedure; A novel study identifying the greater palatine foramen and nerve using ultrasound
Authors: Hafeez Sahar Najmus , Johnson Marjorie , Merrifield Peter , Ganapathy Sugantha , Galil Khadry
Published: June 2021

Background

A greater palatine nerve (GPN) block is required for many dental procedures. Localization of the nerve currently relies on a blind, surface landmark approach, which often requires multiple needle pricks and a large amount of local anesthetic. Ultrasound (US) is a safe, non‐invasive modality and bone appears as a white line on an US. Any disruption in this line may indicate a discontinuity in bone such as a foramen.

Hypothesis

An US‐guided approach can be used to locate the greater palatine foramen (GPF) and isolate the GPN on the hard palate.

Material & Methods

In this study, 16 cadaveric hard palates were scanned by a linear probe and an US‐guided injection of India ink was administered into the GPF of all the specimens.

Result

The hard palate was visible as a white continuous line and an interruption in this line near the maxillary molar teeth was recognized as the GPF in all of the 16 specimens. In 9 out of 16 specimens, traces of India ink were found in the greater palatine canal.

Conclusion

US can be effectively used to visualize both the GPF and GPN in palates with and without molar teeth and an ultrasound guided GPN block could be considered as an adjunct to dental clinics. These findings may warrant follow‐up testing on patients in the dental clinic. The author is supported by OGS funds.

Grant Funding Source: Departmental