bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brain volume of the newly‐discovered species Rhynchocyon udzugwensis (Mammalia: Afrotheria: Macroscelidea): implications for brain‐body allometry within Afrotheria
Authors: Kaufman Jason A. , Turner Gregory H. , Holroyd Patricia A. , Rovero Francesco , Grossman Ari 
Published: June 2021

The Gray‐faced Sengi (Rhynchocyon udzugwensis) is a newly‐discovered species of Sengi (Elephant‐Shrew) and is the largest known extant representative of the order Macroscelidea. The discovery of R. udzugwensis provides an opportunity to investigate the allometric scaling relationship between brain size and body size within the superorder Afrotheria. We performed a 3D spin echo magnetic resonance imaging (MRI) scan on a preserved adult specimen of R. udzugwensis using a 7‐Tesla high‐field MR imaging system. The brain was manually segmented and its volume was compiled into a dataset containing previously‐published allometric data on 29 other species of insectivore‐grade mammals including representatives of Afrotheria, Soricomorpha and Erinaceomorpha. Results of log‐linear regression confirm a strong correlation between brain size and body size among all taxa. Post‐hoc tests indicate a grade‐shift between Macroscelidea and other members of Afrotheria, Soricomorpha and Erinaceomorpha: the Macroscelidea have larger positive brain‐size residuals. As a group, the Macroscelidea have larger brains for a given body size than that observed for the other insectivores. Further research incorporating Hyracoidea, Proboscidea, and Sirenia are necessary for a more‐complete understanding of brain allometry in Afrotheria compared to other Eutherian mammals.This research was supported by an intramural grant from Midwestern University.
Comparison between morphological and morphometric parameters of recurrent laryngeal nerve in developing spontaneously hypertensive rats
Authors: da Silva Greice Anne Rodrigues , Genari Adriana Borges , Salgado Helio Cesar , Fazan Valéria Paula Sassoli 
Published: June 2021

Despite some reports on the peripheral nerve morphology in spontaneously hypertensive rats (SHR), no investigations on the recurrent laryngeal nerve (RLN), known to contain baroreceptor fibers is available in this rat strain. We aimed to describe the normal morphological and morphometric parameters of the recurrent laryngeal nerves in developing SHR. Animals were divided into three groups: Female SHR 5, 8 and 20 week‐old (n=4 in each group). The animals were anesthetized for direct measurement of blood pressure, perfused with a fixative solution and had their right and left RLN, dissected and prepared for light microscopy and morphometry. Body weight increased significantly with aging. Mean arterial pressure was significantly higher in 20‐week old animals compared to 5 week‐old, but not different between 5 and 8‐week old animals or 8 and 20‐week old ones. In general, proximal segments are larger than distal segments with a significant reduction on the myelinated fiber number from proximal to distal. Myelinated fiber size is larger on the older animals, following the increase in body weight. No significant alterations of the nerve morphology were observed in 20‐week old animals, despite the elevated arterial pressure.Grant Funding Source: FAPESP, CNPq, CAPES and FAEPA
A bilateral pudendal nerve injury model in male rats
Authors: Shalhoub Philip J. , Brancato Sam J. , Foecking Eileen M. , Fargo Keith N. 
Published: June 2021

Radical prostatectomy typically results in some degree of urinary incontinence, usually due to dysfunction of the urethral rhabdosphincter consequent to pudendal nerve damage. However, while pudendal nerve injury has been studied in relation to female incontinence, it has largely been neglected in the male literature. Here we describe an animal model of male urethral rhabdosphincter dysfunction following bilateral pudendal nerve compression injury. All subjects were young adult male Sprague‐ Dawley rats. Briefly, a horizontal incision was made between the anus and tail, and the pelvic space exposed. The motor branch of the pudendal nerve was visualized in Alcock's canal and crushed bilaterally (sham controls were not injured). Animals were allowed to survive for 2, 4, 7 or 14 days, then tested for leak point pressure prior to sacrifice. Injured animals displayed variable abnormalities of the urogenital system, usually including one or more of the following: marked urinary retention, hydroureteronephrosis, hematuria, retrograde ejaculation, and/or reduced leak point pressure. These results indicate that bilateral pudendal nerve injury in the male rat leads to a complex pathology of the urogenital system and dysfunction of the urethral rhabdosphincter. This model will be useful for future studies aimed at further elucidating the function of the pudendal nerve and urethral rhabdosphincter in males.Grant Funding Source : VA RR&D CDA‐2 B6598W
Use of a natural latex membrane for nerve grafting: an experimental study
Authors: Ganga Marcos Vinícius Muniz , Fazan Valéria Paula Sassoli , Júnior Wilson Marques , da Silva Lopes Luiza 
Published: June 2021

A membrane produced from a natural latex has been used successfully both experimentally (angioplasties, esophagus neoformation, reconstruction of the ocular conjuntive) and clinically (myringoplasties, treatment of skin ulcers), demonstrating angiogenic potential and leading to tissue neoformation. We evaluated the ability of this natural latex membrane in speeding up and improve the regeneration of sectioned sciatic nerve in rats. Forty adult male Wistar rats were divided in 4 experimental groups (n=10 each) and operated with the auto‐scion or the interposition of a tube made up of that membrane derived from natural latex (Hevea Brasiliensis). After 4 or 8 weeks, animals were submitted to neurological function evaluation, pace evaluation and electromyography. Afterwards, the animals were killed and the nerves were processed for paraffin embedding and observation under light microscopy. Our results indicated that the rats operated with latex have a better recovery rate than the ones operated with autologous nerve duo to the higher use rates of the operated paw. Morphologically, the regenerative capacity of the latex membrane is larger than auto‐scion of the sciatic nerve in rats.Grant Funding Source : FAPESP, CNPq and FAEPA
Influence of painful procedures in the neonatal period in motor and sensory functions of Wistar rats during development
Authors: Carmo Elisabete Cássia do , Machado Nathalia Leilane Berto , Sanada Luciana Sayuri , Fazan Valéria Paula Sassoli 
Published: June 2021

We aimed to evaluate motor and sensory functions in animals exposed to painful stimulation after birth. Wistar rats were separated in: male pain group, 15 days (N=14); male control group, 15 days (N=11); female pain group, 15 days (N=10); female control group, 15 days (N=10); male pain group, 30 days (N=14); male control group, 30 days (N=17); female pain group, 30 days (N=10); female control group, 30 days (N=9); male pain group, 90 days (N=16); male control group, 90 days (N=10); female pain group, 90 days (N=13); female control group, 90 days (N=9); male pain group, 180 days (n=16); male control group, 180 days (N=17); female pain group, 180 days (N=17) and female control group with 180 days of life (N=18). Pain groups were stimulated with a needle while control groups with a cotton swab, both on the right paw, twice a day for 15 days. The grip strength was measured using the Grip Strength Meter. Perimeter of the hindpaw was measured with a caliper rule associated with tape. Sensory function was accessed using Von Frey monofilaments and a calibrated forceps. Control groups had lower body weight than the pain groups. The grip strength, the perimeter of the hind paws, the calibrated forceps and the analysis with the Von Frey of the pain groups showed lower scores than the control groups. Our data suggest that the painful stimulation on neonatal period can influence the motor and the sensory function.Grant Funding Source: FAPESP, CNPq and FAEPA
Application of four‐dimensional computed tomography angiography in the study of vascular structure of the deep inferior epigastric artery perforator
Authors: Wenting Li , Borong Fang 
Published: June 2021

To explore the vascular structure of the deep inferior epigastric artery perforator with the four‐dimensional computed tomography (CT) angiography. 10 abdominal specimens harvested from fresh cadavers were cannulated with trocar and injected with contrast medium in the deep inferior epigastric artery at different levels. During the perfusion of the contrast medium in the flap, the flap was scanned by three‐dimensional CT (four‐dimensional defined as three dimensional CT plus time). The CT data were sent to CT workstation and the images were processed and reformatted. The deep inferior epigastric artery perforator terminates in the subdermal vascular plexus, with bifurcating superior to the Scarps fascia and under the skin. The anastomosis in the abdominal midline occurs in the subdermal vascular plexus. The zone overlying the rectus muscle in the pedicle side has the best blood supply. The four‐dimensional CT is a useful method to study the vascular structure of the deep inferior epigastric artery perforator in the superficial fascia.Grant Funding Source: Institute of Basic Medical Sciences£¬Chinese Academy of Medical Science Funding(2008PY02)
Immunohistochemical Localization of Collagen Types I, III and IV in Fibrotic Livers of Elderly Cadavers
Authors: Mak Ki Mark , Chu Edward 
Published: June 2021

Elderly cadavers with diverse causes of death demonstrated a high prevalence of liver fibrosis, as assessed by Sirius red stain (Mak and Hoo, FASEB J 2011 25: 870.2). The staining, however, did not reveal the chemical types of collagen (Col). Therefore, this study examined localization of Col I, III and IV (the principal Col produced in liver fibrosis) in fibrotic foci of elderly cadavers by immunohistochemistry, using Col I, III or IV antibodies. Col I stained the fiber bundles in fibrotic central veins, perisinusoidal fibrotic foci, stroma of portal tracts, and expanding and bridging fibrous septa. Col III showed a similar localization as Col I. In fibrotic central veins, Col IV stained the endothelial basement membranes and mesenchymal cells. The sinusoidal lining and perisinusoidal cells displayed variable Col IV staining. In portal tracts, Col IV stained the stromal cells and basement membranes of bile ducts and vasculature. Col IV staining also revealed ductular and capillary‐like structures in the matrix of expanding fibrous septa and more strikingly at the septal‐parenchymal and portal‐parenchymal borders.ConclusionsIn elderly cadavers, Col types I, III and IV localize to the fibrotic foci and are reliable markers of liver fibrosis. As liver fibrosis becomes more prominent with aging, fibrotic lesions can be better characterized by combining Sirius red staining with Col I, III and IV detection.
Novel Dose Dependent Positive Feedback Loop in Endothelial Cells: A Response to rhBMP2 Treatment
Authors: Hussein Khaled , Helwa Inas , Zakhary Ibrhaim , Elrefai Rami , Al-Shabrawey Mohamed , Sharawy Mohamed 
Published: June 2021

Recently, we reported that Endothelial Cells (ECs) could be a potential source of endogenous BMP2 which is essential for successful bone regeneration in vivo. The aim of this study was to investigate the capability of ECs to respond to exogenous BMP2 by secretion of endogenous BMP2.MethodsHuman Umbilical Vein Endothelial Cells were treated with serial concentrations of rhBMP2 (25, 50 and 100ng/ml of rhBMP2) for only 3 hours and the cultured cells were maintained for 12 hours. Cell lysates were collected at 5 minutes, 3hours, 6 hours and 12 hours time points after rhBMP2 treatment. ELISA for BMP2 was done to detect its secretion in supernatant at the 6 and 12 hours time points. Real time PCR was done to detect mRNA of BMP2, BMP2R1B and SMAD1/5. Western blot analysis was done to detect the phosphorylation of SMAD1/5/8.ResultsExogenous rhBMP2 significantly induced BMP2 secretion only in the 100ng rhBMP2 treatment at the 6 and 12hours time points consistent with a gradual upregulation of BMP2 mRNA. BMP2R1B, SMAD1 and SMAD5 gene expression were also significantly upregulated. SMAD1/5/8 was consistently phospholyated in the 5 minutes and 3 hours time points.ConclusionECs respond to 100ng/ml rhBMP2 treatment by secreting BMP2 via a SMAD dependent pathway. These results suggest that ECs treated in‐vitro with rhBMP2 could be used as a source of BMP2 in‐vivo to optimize bone regeneration in challenging clinical situations.Grant Funding Source: Ministry of Higher Education, Egypt
A donor model assessing the effect of errant drill passes during placement of femoral nail interlock screws
Authors: Mulchandani Neil , Cataldo Steven , Russo Christen , Hip-Flores David , El-Gendi Hebah , Hayes Westley , Saha Subrata , Márquez Samuel 
Published: June 2021

Current orthopaedic practice to fix femoral shaft and intertrochanteric fractures is intramedullary (IM) nailing. Technical errors in nailing often result in errant drill passes (EDP) during placement of distal interlock screws. This study determined if EDP create stress risers that significantly alter the biomechanical strength of the bone. Ten mm IM femoral nails were placed in 16 paired adult cadaveric distal femur specimens. Matched specimen pairs were randomized into two groups (n=16/group). Nails were statically locked distally with two 4.5 mm bicortical screws in both groups, with specimens in Group 2 being exposed to a 4.2 mm drill hole placed anterior and inferior to the nail, representing an EDP. Using the Instron 8874 Axial‐Torsion Testing System, torsional load to failure and rotational angle at failure were recorded. Student t‐tests revealed no significant decrease in load to failure for the distally locked group with an errant drill pass (p=0.435) or any differences in rotational angle at failure between groups (p=0.581). Introducing an errant drill hole while distally locking a femoral nail did not significantly decrease the specimens’ load to failure indicating that bone strength may remain uncompromised. This suggests that although these technical errors may occur intraoperatively, post‐operative outcomes may remain unaffected.Grant Funding Source : Not Applicable
The myomere‐myoseptal intersections in a lamprey (Petromyzon marinus) and a shark (Squalus acanthias)
Authors: Wood Bradley Morgan , Andermann Roy J. , Homberger Dominique G. 
Published: June 2021

An accurate description of the myomere‐myoseptal intersections of the axial musculature of piscine vertebrates is a necessary basis for a mechanical explanation of how contractile forces are transmitted from one myomere to the next via myosepta. In a lamprey, the tendons of superficial muscle fiber bundles join a myoseptum on each side, but in opposite directions, at shallow to right angles. In a shark, the tendons of superficial muscle fiber bundles traverse a myoseptum to connect to muscle fiber bundles partly directly across and partly diagonally across. Hence, contractile forces of the superficial muscle fiber bundles may be transmitted to each other across the myosepta. The construction of an accurate biomechanical model of the myomeric‐myoseptal intersections may be relevant for a range of questions, such as those pertaining to (1) the biomechanics of serially arranged contractile systems that are also found in the apterial and feather muscles of birds and the sarcomeres of myofibrils; (2) the interactions between the central nervous system and the axial musculature during undulatory locomotion; and (3) the evolutionary changes in the axial musculature of Petromyzontiformes and Chondrichthyes.Funding: LSU Foundation to DGH.Grant Funding Source: N/A
SREBP1c is regulated by E3 ligase RNF20/BRE1A upon hormonal changes
Authors: Lee Jae Ho , Lee Gha Young , Jang Hagoon , Kong Jinuk , Park Yoon Jeong , Kim Jae Bum 
Published: June 2021

Sterol regulatory element binding protein 1c (SREBP1c) is a key transcription factor to regulate de novo lipogenesis. However, molecular mechanisms involved in suppression of SREBP1c are largely unknown. In this study, we reveal that SREBP1c is negatively regulated by ubiquitination upon fasting signals. To better understand which factors are involved in ubiquitination of SREBP1c, we take advantages of affinity purification and mass spectrometry. In this analysis, RNF20/BRE1A is identified as a novel SREBP1c E3 ligase. Here we show that RNF20/BRE1A binds to and ubiquitinates SREBP1c, leading to its degradation. Previously, it has been well established that PKA signaling is activated by fasting signals. Interestingly, we find out that PKA activator such as forskolin enhances expression of RNF20/BRE1A and stimulates ubiquitination of SREBP1c via RNF20/BRE1A. In accordance with these, RNF20/BRE1A negatively regulates the transcriptional activity of SREBP1c and expression of SREBP1c target genes. In contrast, knockdown of RNF20/BRE1A increases expression of SREBP1c and lipogenic genes. Taken together, these data suggest that RNF20/BRE1A would be a negative regulator of lipogenesis through degradation of SREBP1c upon fasting.J. H. Lee was supported by Hi Seoul Science (Humanities) Fellowship funded by Seoul Scholarship Foundation.
E. coli and S. cerevisiae clamp loaders, γ complex and RFC, actively close clamps
Authors: Hayner Jaclyn , Bloom Linda 
Published: June 2021

Sliding clamps and their respective clamp loaders perform integral functions in DNA metabolism and are therefore found throughout all kingdoms of life. Clamp loaders, members of the AAA+ ATPase family, use ATP binding and hydrolysis to load sliding clamps onto DNA where the clamps then serve as a platform for enzymes that act on DNA. In E. coli, the β clamp is loaded by the γ complex clamp loader, and in S. cerevisiae, PCNA is loaded by the RFC clamp loader. Using fluorescent assays developed in our laboratory to report on clamp closing and release, we have shown that the rate of clamp closing is about 10 times faster than the rate of clamp release for both systems, indicating that these clamp loaders actively close clamps. When ATP hydrolysis is blocked, the closing and release rates become similar, indicating that the mechanism of closing before release is ATP hydrolysis‐dependent. ATP hydrolysis experiments were performed using fluorescently labeled phosphate binding protein to determine the rate of ATP hydrolysis and a temporal correlation between ATP hydrolysis and clamp closing. These experiments identify a common mechanistic feature in the clamp loading reaction and help to understand how these enzymes efficiently load clamps for replication and repair.This work supported by NIH grant GM 082849 and 5 T32 CA009126‐32 Training Grant in Cancer Biology
Genetic and Proteomic Dissection of TDP43 Toxicity in S. cerevisiae
Authors: Higgins Matthew James , Krogan Nevan J , Farese Robert V 
Published: June 2021

The RNA binding protein transactivator region DNA‐binding protein 43 (TDP43) was identified in ubiquitin‐positive aggregates in patients with frontotemporal dementia (FTD), and subsequent studies have demonstrated that TDP43 is associated with several neurodegenerative diseases including amytrophic lateral sclerosis (ALS) and Alzheimer disease. The mechanism by which TDP43 contributes to neurodegenerative disease is not understood. Similarly, whether TDP43‐toxicity results from a gain‐ or loss‐of‐function is unclear and will likely require a molecular understanding of how TDP43 functions as a protein‐ and RNA‐scaffold under normal and toxic conditions. To gain insight into the mechanism of TDP43 toxicity, we performed a synthetic genetic array screen in Saccharomyces cerevisiae by using the deletion and decreased abundance by mRNA perturbation (DAmP) gene collections. We have identified a variety of genes whose deficiency suppresses or enhances TDP43 toxicity, including several involved in pathways of RNA metabolism. Additionally we have identified many proteins associated with TDP43 expressed in S. cerevisiae, some of which participate in pathways similar to those that were identified in the genetic screen. Constructing a more detailed proteomic and genetic network of modifiers of TDP43 toxicity will allow a better understanding of TDP43 normal and pathogenic function and, hopefully, enable more directed approaches to therapies targeting neurodegenerative diseases involving TDP43.Funding to RVF Jr. from the Consortium for Frontotemporal Dementia Research
Role of the Cofactor in the Catalytic Mechanism of the glmS Ribozyme
Authors: Claverol Julia Viladoms , Fedor Martha J. 
Published: June 2021

The glmS ribozyme is the first natural self‐cleaving ribozyme that requires a cofactor. A cofactor can greatly expand the number of reactions that RNA can catalyze because it contributes chemical diversity that is otherwise not available with only four nucleotides. Although it has been proposed to serve as a general acid, the role of the cofactor in the glmS catalytic mechanism is unclear.We surveyed different molecules for their ability to support self‐cleavage of the glmS ribozyme and found a strong correlation between the pH dependence of the cleavage reaction and the intrinsic acidity of each cofactor. Self‐cleavage of the glmS ribozyme also depends on the concentration of the free base form of the cofactor, evidence that the reaction is subject to general base catalysis. Mechanistically, this behavior may correspond to true general base catalysis, with the cofactor accepting a proton, or to specific base general acid catalysis, with a hydroxide ion accepting a proton and the cofactor donating one.We are currently acquiring pre‐steady state kinetics of glmS ribozyme self‐cleavage promoted by several cofactors that differ in intrinsic Brønsted base strength and binding affinity to apply linear free energy relationships. The results of these experiments will provide insight into how the cofactor contributes to the glmS catalytic mechanism.This work was supported by NIH RO1 GM046422.
Mutational and kinetic analysis of the endosome‐associated deubiquitinating enzyme, AMSH
Authors: Davies Christopher Williamson , Kim Myung-Il , Paul Lake N , Das Chittaranjan 
Published: June 2021

The endosomal‐sorting complexes required for transport (ESCRT) is a ubiquitin‐mediated process that is implicated in endosomal sorting, trafficking, and viral budding. The ESCRT machinery regulates signaling events by internalizing cell surface receptors and targeted them for degradation by the lysosome. Two deubiquitinating enzymes (DUBs) regulate the activity of the ESCRT complex, STAM‐binding protein (AMSH), and ubiquitin specific protease Y (UBPY), by counteracting the ubiquitination of the cargo. Recently, we published two crystal structures of the catalytic domain of AMSH, and biochemical and modeling studies revealed that AMSH is significantly different from the ESCRT‐independent, AMSH‐like protein (AMSH‐LP) in its stability and ubiquitin recognition.. In the present study, we sought to understand AMSH's mode of substrate recognition, through mutational analysis. Surprisingly, we have discovered a point mutant that shows higher catalytic activity than the wild‐type enzyme. These results support the idea that AMSH is conformationally plastic, which may be biologically relevant. The mechanism of activation and its implication in the functional role played by AMSH within ESCRT complex will be discussed. Results from our studies could provide further insight into understanding the role of AMSH within the ESCRT complex.Support: NIH (1R01RR026273) and the Indiana Space Grant Consortium