bluuebunny/crossref_metadata_2025 huggingface dataset:
Results of a prospective follow-up study after type A aortic dissection repair: a high rate of distal aneurysmal evolution and reinterventions
Authors: Gaudry Marine , Porto Alizée , Guivier-Curien Carine , Blanchard Arnaud , Bal Laurence , Resseguier Noemie , Omnes Virgile , De Masi Mariangela , Ejargue Meghann , Jacquier Alexis , Gariboldi Vlad , Deplano Valérie , Piquet Philippe
Published: June 2021

OBJECTIVES

We investigated the anatomical evolution of residual aortic dissection after type A repair and factors associated with poor prognosis at a high-volume aortic centre.

METHODS

Between 2017 and 2019, all type A aortic dissections were included for prospective follow-up. Patients without follow-up computed tomography (CT) scan available for radiological analysis and patients without residual aortic dissection were excluded from this study. The primary end point was a composite end point defined as dissection-related events including aneurysmal evolution (increased diameter > 5 mm/year), aortic reintervention for malperfusion syndrome, aortic diameter >55 mm, rapid aortic growth >10 mm/year or aortic rupture and death. The secondary end points were risk factors for dissection-related events and reintervention analysis. All immediate and last postoperative CT scans were analysed.

RESULTS

Among 104 patients, after a mean follow-up of 20.4 months (8–41), the risk of dissection-related events was 46.1% (48/104) and the risk of distal reintervention was 17.3% (18/104). Marfan syndrome (P < 0.01), aortic bicuspid valve (P = 0.038), innominate artery debranching (P = 0.025), short aortic cross-clamp time (P = 0.011), initial aortic diameter >40 mm (P < 0.01) and absence of resection of the primary entry tear (P = 0.015) were associated with an increased risk of dissection-related events or reintervention during follow-up.

CONCLUSIONS

Residual aortic dissection is a serious disease requiring close follow-up at an expert centre. This study shows higher reintervention and aneurysmal development rates than currently published. To improve long-term outcomes, the early demographic and anatomic poor prognostic factors identified may be used for more aggressive treatment at an early phase.
Effectiveness of the Wearable Sensor-based Ambient Intelligent Geriatric Management (AmbIGeM) System in Preventing Falls in Older People in Hospitals
Authors: Visvanathan Renuka , Ranasinghe Damith C , Lange Kylie , Wilson Anne , Dollard Joanne , Boyle Eileen , Jones Katherine , Chesser Michael , Ingram Katharine , Hoskins Stephen , Pham Clarabelle , Karnon Jonathan , Hill Keith D
Published: June 2021

Background

The Ambient Intelligent Geriatric Management (AmbIGeM) system augments best practice and involves a novel wearable sensor (accelerometer and gyroscope) worn by patients where the data captured by the sensor are interpreted by algorithms to trigger alerts on clinician handheld mobile devices when risk movements are detected.

Methods

A 3-cluster stepped-wedge pragmatic trial investigating the effect on the primary outcome of falls rate and secondary outcome of injurious fall and proportion of fallers. Three wards across 2 states were included. Patients aged ≥65 years were eligible. Patients requiring palliative care were excluded. The trial was registered with the Australia and New Zealand Clinical Trials registry, number 12617000981325.

Results

A total of 4924 older patients were admitted to the study wards with 1076 excluded and 3240 (1995 control, 1245 intervention) enrolled. The median proportion of study duration with valid readings per patient was 49% ((interquartile range [IQR] 25%-67%)). There was no significant difference between intervention and control relating to the falls rate (adjusted rate ratio = 1.41, 95% confidence interval [0.85, 2.34]; p = .192), proportion of fallers (odds ratio = 1.54, 95% confidence interval [0.91, 2.61]; p = .105), and injurious falls rate (adjusted rate ratio = 0.90, 95% confidence interval [0.38, 2.14]; p = .807). In a post hoc analysis, falls and injurious falls rate were reduced in the Geriatric Evaluation and Management Unit wards when the intervention period was compared to the control period.

Conclusions

The AmbIGeM system did not reduce the rate of falls, rate of injurious falls, or proportion of fallers. There remains a case for further exploration and refinement of this technology given the post hoc analysis findings with the Geriatric Evaluation and Management Unit wards.

Clinical Trials Registration Number: 12617000981325
Cognitive Reserve Moderates Associations Between Walking Performance Under Single- and Dual-Task Conditions and Incident Mobility Impairment in Older Adults
Authors: O’Brien Catherine , Holtzer Roee
Published: June 2021

Background

Among older adults, walking performance is a reliable indicator of adverse health outcomes including incident mobility impairment. Whereas, attention and executive functions have been implicated in cognitive control of locomotion, much less is known about the role of cognitive reserve (CR) in predicting mobility impairments among older adults. Specifically, whether CR moderates the relationship between gait performance and incident mobility impairment has not been reported. To address this gap in the literature, we examined whether gait performance under single-task walk (STW) and dual-task walk (DTW) conditions predicted incident mobility impairment and whether CR moderated this relationship.

Method

Participants were 176 (mean age = 75.57; % female = 53) older adults with baseline Short Physical Performance Battery (SPPB) scores of 10–12. Participants completed neuropsychological testing, the SPPB, and a DTW protocol. CR was evaluated using the Wide Range Achievement Test, third edition. Participants were followed for 3 years; individuals whose SPPB scores declined below 10 were defined as incident cases of mobility impairment (n = 42).

Results

Moderation analyses revealed significant interaction effects of CR with walking velocity under STW (b = 0.09, 95% CI [0.01, 0.17], z = 2.30, p = .02) and DTW (b = 0.10, 95% CI [0.02, 0.17], z = 2.55, p = .01) conditions, wherein slower gait predicted increased risk of incident mobility impairment among individuals with lower CR.

Conclusion

These findings extend knowledge about the interrelation of cognitive and mobility functions, revealing the critical role of CR in identifying older adults at risk of developing incident mobility impairment.
Midlife Vision Impairment and Cognitive Function in Later Life: The Study of Women’s Health Across the Nation, Michigan Cohort
Authors: Kolli Ajay , Hood Michelle M , Karvonen-Gutierrez Carrie , Moroi Sayoko E , Ehrlich Joshua R , Gillespie Brenda W , Dougherty Wood Sarah , Musch David C
Published: June 2021

Background

In older adults, vision impairment (VI) is associated with worse cognitive function. However, the relationship between midlife vision and future cognitive function remains unknown.

Methods

The Study of Women’s Health Across the Nation, Michigan site, is a longitudinal cohort of midlife women aged 42–52 years at baseline. Presenting Titmus visual acuity (VA) in the better-seeing eye was assessed at baseline and categorized as no or mild VI (VA ≥20/60), or moderate or worse VI (VA <20/60). Cognitive function was measured 8 times over 15 years using the East Boston Memory Test immediate (EBMTi) and delayed (EBMTd) recall and the Digit Span Backwards (DSB) test. Linear mixed models with a random intercept and slope for age were constructed to detect associations between VI at baseline and future repeated measures of cognitive function, adjusting for age, race, education, financial strain, alcohol use, and tobacco use.

Results

About 394 women aged 42–52 at baseline with a maximum follow-up of 20 years were included in this analysis. After covariate adjustment, moderate or worse VI was associated with lower EMBTi (β = −0.56, p = .012), EBMTd (β = −0.60, p = .009), and DSB (β = −0.84, p = .04). While we detected significant associations between VI and levels of cognitive function scores, rates of cognitive decline as individuals aged did not vary by VI status.

Conclusion

Moderate or worse VI, assessed during midlife, was associated with lower scores on measures of cognitive function over a 15-year period during which women transitioned from midlife to older adulthood.
Associations Between Changes in Daily Behaviors and Self-Reported Feelings of Depression and Anxiety About the COVID-19 Pandemic Among Older Adults
Authors: Robbins Rebecca , Weaver Matthew D , Czeisler Mark É , Barger Laura K , Quan Stuart F , Czeisler Charles A
Published: June 2021

Objectives

Due to the significant mortality and morbidity consequences of the coronavirus disease 2019 (COVID-19) pandemic among older adults, these individuals were urged to avoid going out in public and socializing with others, among other major disruptions to daily life. While these significant and often unavoidable disruptions have been shown to bear consequences for mental health, less attention has been devoted to behavioral changes, such as changes to sleeping or eating due to the COVID-19 pandemic, and their implications for emotional well-being.

Methods

We utilized data from a nationally representative survey of Medicare beneficiaries (aged 65 and older), which was administered between June and October 2020 (n = 3,122). We examine the relationship between self-reported changes to daily behaviors (e.g., sleep, drinking alcohol, and exercise) and emotional impacts of the COVID-19 pandemic (i.e., feelings of depression and anxiety about the COVID-19 pandemic) using stepwise hierarchical multivariable Poisson regression.

Results

We found that worse sleep quality, sleeping more or less, watching more television, and walking less were associated with more feelings of depression and anxiety about the COVID-19 pandemic.

Discussion

Previous research has shown a connection between the significant and often unavoidable disruptions to daily life due to the COVID-19 pandemic (e.g., sheltering in place) and adverse mental health symptoms. Less attention has been paid to potentially modifiable behaviors, such as sleep and exercise. Our findings highlight the behavioral changes associated with adverse emotional impacts among older adults during the COVID-19 pandemic. Future research may evaluate whether behavioral interventions may aim to attenuate the impact of pandemics on daily, modifiable behaviors to buffer against adverse emotional impacts.
The COVID-19 Pandemic Introduces Diagnostic and Treatment Planning Complexity for Individuals at Clinical High Risk for Psychosis
Authors: Mittal Vijay A , Walker Elaine F , Strauss Gregory P
Published: June 2021

COVID-19 has led to a great deal of general suffering and an increased prevalence of psychiatric illness worldwide. Within the area of psychosis-risk syndromes, a highly heterogeneous clinical population, the picture is quite nuanced as the social restrictions resulting from the pandemic have reduced stress for some and increased it for others. Further, a number of pandemic-related societal and cultural changes have obfuscated the diagnostic and treatment landscape in this area as well. In this opinion article, we describe several prototypical cases, representative of presentations seen in our clinical high-risk (CHR) research programs. The cases highlight considerable clinical variability and, in addition, speak to the current complexities faced by diagnosticians and treatment providers. In addition to discussing these issues, this piece introduces potential solutions highlighting the promise of incorporating data-driven strategies to identify more homogenous CHR subtypes and employ precision medicine.
Functional Characterization of Gene Regulatory Elements
Authors: Ahituv Nadav
Published: June 2021

Nucleotide variation in gene regulatory elements is a major determinant of phenotypes including morphological diversity between species, human variation and human disease. Despite continual progress in the cataloging of these elements, little is known about the code and grammatical rules that govern their function. Deciphering the code and their grammatical rules will enable high‐resolution mapping of regulatory elements, accurate interpretation of nucleotide variation within them and the design of sequences that can deliver molecules for therapeutic purposes. To this end, we are using massively parallel reporter assays (MPRAs) to simultaneously test the activity of thousands of gene regulatory elements in parallel. By designing MPRAs to learn regulatory grammar or to carry out saturation mutagenesis of every possible nucleotide change in disease causing gene regulatory elements, we are increasing our understanding of the phenotypic consequences of gene regulatory mutations. To better understand how nucleotide changes in gene regulatory elements lead to morphological differences between species, we are using the developing bat wing as a model. Using a combination of whole‐genome sequencing, RNA‐seq and ChIP‐seq (H3K27ac, H3K27me3) on developing bat and mouse forelimbs and hindlimbs at three sequential embryonic stages, we are attempting to decipher the molecular events that underlie bat wing development.

Support or Funding Information

NICHD, NCI, NHGRI, NIMH, NHLBI

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Complete Regeneration of a Camera‐type Eye in the Research Organism Pomacea canaliculata
Authors: Accorsi Alice , Ross Eric , McClain Melainia , McKinney Sean , Alvarado Alejandro Sánchez
Published: June 2021

The vertebrate single‐chambered camera eye is comprised of a cornea, an iris, a lens, a retina and an optic nerve. Although their sensitivity and image resolution are astonishing, their regenerative capacities are either limited or absent. A few amphibians and fishes are able to repair specific ablations of the cornea, lens or retina through the activation of cells in the ciliary marginal zone, but complete regeneration of their eyes after full removal has not been observed. Histological staining, electron microscopy and transcriptome analyses indicate that the camera‐type eyes of the freshwater snail Pomacea canaliculata (Gastropoda, Ampullariidae) are not only anatomically comparable to vertebrate eyes, but also able to regenerate de novo after complete amputation. Applying the same techniques to study embryonic eye development in P. canaliculata revealed a striking similarity between adult eye regeneration and embryonic eye development, particularly in terms of main morphological steps required for building a new eye and the timing required for developing and differentiating every component. While we are far from being able to state whether eye regeneration recapitulates embryonic eye development, our ability to culture embryos will allow us to formally compare embryonic and post‐embryonic processes such as regeneration to each other. In sum, an important set of tools have been developed to interrogate P. canaliculata biology and spur the establishment of genome editing and gene function perturbation technologies in this research organism.

(Reported investigations have been conducted in conformance with the FASEB Statement of Principles for the use of Animals in Research and Education.)

Support or Funding Information

Alice Accorsi is American Association of Anatomists Scholar and Society of Developmental Biology member and this research was in part funded by both the American Association of Anatomists and the Society of Developmental Biology. This research was also funded by Howard Hughes Medical Institute and Stowers Institute for Medical Research.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Educational Avenues to Promote Fascia Dialog in Medical Curricula
Authors: Pratt Rebecca
Published: June 2021

The concept of fascia belongs in medical training. It is important that all physicians be introduced to the continuum of connective tissue. Fascia serves as one of the body's fundamental “connectors”. Visualizing the amazing range of fascia at the gross level, from adipose to tendons, is a good first introduction for students in dissection or prosection. Teaching the role of dense connective tissue in compartmentalizing muscles and neurovascular bundles is a wonderful way to familiarize students with pattern recognition in gross anatomy. Without teaching fascia we might lose the opportunity to discuss planes and clefts for surgical access, muscle group actions and pathologies such as compartment syndrome. Fascia also serves as a means of providing students with a contextual environment for discussing the intricacies of signal transduction pathways and biochemical cycles. Without the extracellular matrix and the addition of cells to form fascia we lose the scaffolding for our physiological switchboard‐operators critical in the day to day monitoring of homeostasis. This presentation will refer to the courses taught at Michigan State University School of Osteopathic Medicine as examples of approaches to demonstrate the significance of fascia in medicine. As long as one of the physician's goals remains to help their patients return to a state of homeostasis and well‐being, fascia will have a place in medical curricula.

Support or Funding Information

Funding support not applicable.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Molecular Targets Underlying the Anti‐inflammatory Effects of Thymoquinone in LPS activated BV‐2 Cells
Authors: Taka Equar , Mendonca Patricia , Mazzio Elizabeth A. , Reed Selina Darling , Reams Renee , Soliman Karam F.
Published: June 2021

Excessive production of pro‐inflammatory cytokines in the brain have been implicated in several neurodegenerative diseases such as Alzheimer's diseases. Microglia is the primary immune cells of the brain, and when activated they release various pro‐inflammatory cytokines. Natural compounds such as thymoquinone (TQ) that have an anti‐inflammatory, anti‐oxidant, and anticancer activities may offer a promising strategy for inflammation‐mediated neurodegenerative disorders involving activated microglia cells. Our previous study showed that exposure to TQ in activated microglia reduces several cytokines/chemokines including IL‐6, MCP‐5, IP‐10, MCP‐1 and nitric oxide. The purpose of this study was to investigate the global molecular targets underlying the anti‐inflammatory effects of TQ. In this study, microglia BV‐2 cells were first stimulated for 1 hr. with 1μg/mL lipopolysaccharide (LPS); then incubated for 24 hr. in the presence or absence of 10 μM TQ. Genomic and proteomic approaches were used to identify target genes and proteins of TQ in activated microglia BV‐2 cells. Genomic results showed that TQ significantly decreases gene expression of miR‐155 by 3.9 folds, JAK2 by 2.2 folds, CCL5 by 13.2 folds, CCRL2 by 12 folds, and PTGS2 (COX2) by 3.3 folds in LPS‐stimulated BV‐2 cells. Proteomics results also showed that TQ significantly decreases protein expression of NOS by 10 folds and Tyrosine‐protein kinase (SYK) by 8 folds. Our results showed that TQ significantly decreased genes and proteins involved in activated microglia‐mediated inflammation. These results suggest that TQ could be an effective treatment for neuroinflammation that occurs in neurodegenerative diseases such as Alzheimer's diseases.

Support or Funding Information

This study was supported by the National Institute on Minority Health and Health Disparities awards G12MD007582 and P20 MD 00738.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Student Approach to Learning in a Bachelor Level Cadaver Dissection Course
Authors: Fretham Stephanie
Published: June 2021

The objective of this study was to determine how students' approach to learning changes through a semester‐long cadaver dissection course and if in‐class and online integrative drawing and concept‐mapping exercises can shift student approach to learning and diversity of study methods employed. Study participants were 67 fourth‐year bachelor students from two cohorts of a semester‐long anatomy course with lecture and cadaver dissection. At the beginning and end of the course students completed the revised two‐factor Study Process Questionnaire (Biggs, British Journal of Educational Psychology, 2001, 71, 133–149) to assess deep and surface motivation and strategies in their approach to learning. At the same time students responded to open‐ended questions regarding study methods. Course exercises included demonstrations of concept mapping, time in lecture for group work, and online forums where students posted diagrams responding to prompts asking students to integrate sympathetic and parasympathetic innervation, or the muscles, innervations, and secretions within the digestive system. Some individual students showed major shifts in their approach to learning however there was not a significant overall trend toward either deep or surface learning over the course and no influence of participation in the class exercises on approach to learning. There was a modest positive correlation between deep approach to learning at the end of the course and overall performance (r=0.30, p<0.05). In conclusion, the class exercises did not measurably alter student approach to learning, but open‐ended questions indicated that students enjoyed the integrative exercises and felt the skills they learned were applicable in other courses. This perceived value of the exercises could be more generally attributed to an increased awareness of the learning process.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Teaching and learning for long term retention
Authors: Easteal Ronald , Perry Carolyn
Published: June 2021

Anatomy is generally considered by students to be a subject that is simply learned through assimilation of facts. Unfortunately, this type of strategy both ill‐equips students to form connections between material and ill‐prepares them for more complex learning that is necessary in medical curriculums. It has been shown previously (Regpalla & Easteal, 2013) that retrieval practice improves results in large gross anatomy classes and we are currently assessing the benefit of sleep consolidation in the hard wiring of anatomical information that would provide the basis for more complex learning when required. These results, and others, will be highlighted in a discussion describing teaching and learning techniques used in 2nd and 3rd year pre‐med courses in gross anatomy that have optimized up‐to‐date teaching and memory strategies. The presentation will involve the discussion of the following teaching techniques: cognitive load application, spiral syllabus, association (or congruency), constructive alignment, and the use of document cameras. In addition, descriptions of memory acquisition techniques will include: 1) study of lecture material within 3 hours of sleep, 2) sleep acquisition of ‘recent memory’, 3) once‐a‐week labs in both an anatomical dissection room and museum (+1200 specimens), and 4) the use of retrieval practice to enhance long term memory (which has been shown to be more than twice as effective as studying for long term memory: Karpicke & Roediger, 2008). Moving forward, the hope is that the discussion of these teaching and learning techniques, as currently used in gross anatomy courses, will provide educators with examples of how they can be implemented into course curriculum with the aim of improving student learning and long‐term retention.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Clinical Application of the Left Coronary Artery Variation: A Cadaveric Study
Authors: Klinkhachorn Penprapa S. , Kumar Anil , Moore Valerie A. , Ajmani Madan L.
Published: June 2021

Coronary arteries play an important role in perfusion of the heart tissues. Variations or anomalies of coronary arteries may be asymptomatic, while some can be symptomatic and may even cause sudden death. Knowledge of coronary artery variations is important in diagnosing and treating cardiovascular diseases. The aim is to describe variations of the LCA and its branching patterns. A total of 78 human hearts were dissected, examined and measured. The external diameters at the starting points of these branches were measured using 0.01 mm sensitive digital calipers. The data is reported as mean ± standard deviation. The mean outer diameter of left coronary artery (LCA), left anterior descending (LAD) and circumflex artery (CA) was 4.34 ± 2.01 mm, 4.21 ± 0.28 mm, and 2.73 ± 0.6 mm respectively. Whereas the mean length of LCA, LAD and CA was 10.2 ± 3.5 mm, 83.4 ± 17.8 mm, and 44.6 ± 17.9 mm respectively. The main trunk of LCA bifurcated in 63 specimens (80.76%), trifurcated in 8 specimens (10.25%), quadrifurcated in 6 specimens (7.69%) and pentafurcated in 1 specimens (1.28%). Variation in the origin of coronary arteries and their branching pattern can pose difficulties in imaging by conventional catheters, thereby creating problems in diagnostic and therapeutic interventions. It is also an increasingly vital component in the management of congenital and acquired heart diseases. The short main LCA explains some failures of adequate coronary perfusion from aortic valve surgery, as the myocardial perfusion depends on the placement of one or more cannulas in the coronary arteries. Short LCA trunk is also considered as a risk factor in developing coronary atherosclerosis, which can lead to much more serious complications than those of the RCA. In conclusion, the high degree of variability of the LCA and its branching patterns has anatomical, pathophysiological diagnostic and therapeutic implications. Adequate knowledge of these variations is important for the interpretation of coronary angiography, stenting procedures and surgical myocardial revascularization.

Support or Funding Information

Supported in parts by WVU Health Sciences Center and Oman Medical College

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Maturational Change in Quiet Respiration Versus Respiration While Feeding In Infant Mammals
Authors: German Rebecca Z. , Gould Francois D.H.
Published: June 2021

Respiratory rhythm and rate differ in quiet respiration as compared to respiration when infants are suckling and swallowing. How this difference changes in neonates up through the time of weaning is unknown. We tested the hypotheses that (1) rhythm and rate change with age as a function of increasing size but that (2) significant changes in the coordination of respiration with swallowing reflect an increased ability to protect the airway in advance of weaning. We obtained a sample of 9 infant pigs from two unrelated litters and measured quiet respiration, either while sleeping or anesthetized, from 3 to 24 days of age. In the same animals, we measured respiration while feeding from 7 to 24 days of age. Quiet respiration was recorded with a plesthymograph, either while animals were sleeping or lightly anesthetized. Respiration and feeding was recorded using simultaneous high speed videoflurography (XROMM) and plesthysmography. We found minor changes with age in quiet respiration. The within‐session, usually about 1 minute, variation in respiratory rate, decreased significantly with age. Variation in respiration during feeding did not change with age. However, the timing of the coordination between swallowing and respiration changed significantly as animals approached weaning age. The maturational differences in the two types of breathing may reflect different aspects of development. The reduction in variation in quiet respiration may be due to a maturing nervous system, whereas the changes in timing and coordination between swallowing and breathing may be necessary for airway protection as young mammals move to eating solid food.

Support or Funding Information

This work is supported by NIH HD088561 to RZG.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Possible protective effect of statins against renal ischemic‐reperfusion injury in diabetic rats: a biochemical and histochemical study
Authors: Hassan Sherif S. , Rizk Ayman , Ettarh Rajunor
Published: June 2021

Background

Acute renal failure may complicate ischemic‐reperfusion injury (IRI) due to the production of reactive oxygen species. Atorvastatin (ATO) is well known for its antioxidant and antiinflammatory effects. It may be possible to protect against acute renal failure by preventing IRI.

Aim of study

The current study has been carried out to investigate the protective effect of ATO against renal IRI in diabetic rats.

Methods

The current study used 2 groups of rats, A and B, (18 rats each). Group A (non‐diabetic) was subdivided into: Group A1 (non‐diabetic sham), Group A2 (non‐diabetic IRI), Group A3 (non‐diabetic ATO‐treated + IRI). Group B (diabetic) was subdivided into: Group B1 (diabetic sham), Group B2 (diabetic IRI), and Group B3 (diabetic ATO‐treated + IRI). All rats were subjected to renal ischemia, bilaterally, for 45 minutes, followed by reperfusion for 24 hours. Rats in Groups A3 and B3 were injected with single doses of ATO (10 mg/kg), intraperitoneal, half hour before induction of renal ischemia. Serum kidney functions including blood urea nitrogen (BUN) and creatinine, and oxidative stress markers in renal tissue homogenate, including malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), superoxide dismutase (SOD), and glutathione reductase (GR), were studied to measure renal IRI.

Results

Groups A2 and B2 revealed marked increase in BUN, creatinine, MDA, and iNOS and a decrease in SOD and GR. Corresponding results in Groups A3 and B3 suggested improvement in both, the kidney function tests and the oxidative stress markers. This improvement was more significant in Group A3 than Group B3. Study data were analyzed using SPSS and data were described as mean ± standard deviation (SD). Comparisons were performed using one‐way analysis of variance. Differences between mean values were assessed using a t test. A P<.05 was considered statistically significant.

Conclusion

ATO can improve renal IRI, both, in non‐diabetic and diabetic rats, however, its protective effect was less in diabetic rats.

Support or Funding Information

This study was self‐funded.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Intrinsically Disordered Regions/Proteins Compensate For Genomic Economization In Mycobacterium Tuberculosis
Authors: Ehtesham Nasreen Zafar , Ahmad Javeed , Farhan Aisha , Khubaib Mohd , Kaur Simran , Pancsa Rita , Srinivasan Alagiri , Kumar Saroj , Babu Madan , Hasnain seyed Ehtesham
Published: June 2021

Central to the emergence of Mycobacterium tuberculosis (M. tb) as an extremely successful pathogen is its predilection to persist within the hostile host environment. In this context, the role of disordered proteins and linear motif rich intrinsically disordered proteins (IDPs) to perturb and hijack host cell networks for a productive infection holds special importance. M.tb has a relatively high percentage of IDPs in its proteome among prokaryotes, the significance of which is not known. Moreover, M.tb has evolved through reductive evolution, with the exception of PE‐PPE/PGRS protein family, which has been expanding in pathogenic mycobacteria. Here, we analyzed the M.tb proteome and its entire secretome. PE‐PGRS subfamily and the secretome were enriched in disorder and disordered binding sites, implying that structural disorder might be important for host‐pathogen interactions. We studied the PPE37 protein in more detail that carries an N‐terminal PPE domain capable of iron binding followed by two transmembrane domains and a disordered C‐terminal segment harboring number of eukaryotic linear motifs (ELMs). N‐terminal segment caused proliferation and differentiation of monocytic THP‐1 cells into CD11c, DC‐SIGN positive semi‐mature dendritic cells. The C‐terminal segment localizes to macrophage nucleus and induced caspase‐3 dependent apoptosis of host cells. We also studied the structural shift in PE35‐PPE68 and PE32‐PPE65 protein pairs of pathogenesis‐related RD1 and RD8 regions by analyzing their secondary structure through Fourier transformed infrared spectroscopy. These disordered proteins displayed a remarkable structural shift from disorder to order while engaging in the formation of complexes. These proteins are immunogenic individually and enhance pro‐pathogen response; however, their corresponding complexes enhanced the responses manifold in immunized mice. These results support the role of IDPs in performing contrasting activities to modulate the host processes possibly through molecular mimicry and cross talk. The results from our study further reinforce structural dynamics as a strategy to subvert host defence and to compensate genomic content loss due to reductional evolution.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Metacaspases of the Fungus S. commune Are Activated by Calcium and Specific for Arginine
Authors: Leang Lakhena , Fox Kristin M.
Published: June 2021

Metacaspases belong to a class of cysteine peptidase protein enzymes and are known to be involved in several programmed cell death (PCD) mechanisms in plants and lower eukaryotes. Similar to caspases, metacaspases contain a cysteine‐histidine catalytic dyad and can undergo autoprocessing for increased activity. However, these proteases cleave after arginine or lysine residues, while caspases are aspartate specific. Previous studies have shown that Ca2+ plays a critical role in metacaspase activity. The metacaspase structures of MCA2 (Trypanosoma brucei) and YCA1 (Saccharomyces cerevisiae) have been found to contain calcium‐binding site(s) necessary for complete enzyme activity. A subset of metacaspases possesses an N‐terminal prodomain containing a proline rich sequence. We have identified five metacaspase genes in this subset from the split‐gilled fungus Schizophyllum commune (ScMC1‐5). All genes for ScMC1‐5 have been cloned with and without the prodomain (Δpro) into a SUMO vector construct, expressed, purified and tested for enzymatic activity.

The goal of this project was to characterize ScMC1‐5Δpro by determining substrate specificity, optimal Ca2+ concentrations, and optimal pH levels for each enzyme using a metacaspase fluorogenic activity assay. Results show that all ScMC1‐5Δpro showed arginine and lysine specificity, with higher efficiency for arginine. All enzymes performed best within a pH range of 7 and 8. Optimal calcium concentrations ranged from 5 mM to 50 mM Ca2+. Only ScMC1Δpro is completely inactive at 0 mM calcium. ScMC1&5Δpro have a much higher optimal concentration (50 mM), compared to ScMC2, 3 and 4Δpro, suggesting that calcium may have different binding affinities and play different roles in each enzyme. These data agree with current literature for other similarly characterized metacaspases. Increasing our understanding of metacaspase enzymes could provide vital information for the development of future anti‐fungal and antibacterial treatments.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Exploring Subunit Communication of Malate Dehydrogenase through Interface Point‐ Mutations
Authors: Schwabe Michael , Shania Sharon , Garcia Nina Marie , Graham Sasha , Bell Ellis
Published: June 2021

Malate Dehydrogenase (MDH) catalyzes the oxidation/reduction of malate/oxaloacetate through coupling with NAD+/NADH conversion, a key area in cellular metabolism and has been shown to be regulated by citrate. MDH is a homo‐dimer and x‐ray structures show a flexible loop, which upon substrate or citrate binding induces a closed conformational in one subunit, while the other remains open. This implies an as of yet unknown means of communication between the two subunits to convey the open/closed loop response. Concurrent work in the Bell Lab has shown two mutations, S266A & L269A, located in the active site and interface regions display significant changes in kinetic parameters. To further probe these regions and assess individual residue contributions to subunit communication several additional point mutants (I88A, K261M/Q, S270A/C, T255E/V) located between the active site and the subunit interface have been constructed, expressed, purified and characterized. The I88A mutant protein has a 10,000 fold decrease in Vmax while that of the T255E mutant is decreased 1,000 fold. Km for NADH is significantly increased in the I88A mutant while that for T255E remains unchanged. This suggests that decreased affinity for NADH in the I88A mutant results from disruption of the subunit interface., I88 is thought to interact with L269 on the opposite chain, while T255 may be involved in oxaloacetate/malate/citrate binding at the active site. This data is consistent with predicted effects of interface and active site mutations and contributes to a detailed understanding of a predicted inter‐subunit relay system to induce asymmetric conformational changes and ligand binding in this homo‐dimeric enzyme.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Highly Sensitive and Selective Determination of Redox States of Coenzymes Q9 and Q10 in Mice Tissues: Application of HR/AM Orbitrap Mass Spectrometry
Authors: Tiziani Stefano
Published: June 2021

Coenzyme Q (CoQ) is a redox active molecule that plays a fundamental role in mitochondrial energy generation and functions as a potent endogenous antioxidant. Redox ratio of CoQ has been suggested as a good marker of mitochondrial dysfunction and oxidative stress. Nevertheless, simultaneous measurement of redox states of CoQ is challenging owing to its hydrophobicity and instability of the reduced form. In order to improve the analytical methodology, paying special attention to this instability, we developed a highly sensitive and selective high‐resolution/accurate‐mass (HR/AM) UPLC‐MS/MS method for the rapid determination of redox states of CoQ9 and CoQ10 by ultra‐performance liquid chromatography‐hybrid quadrupole‐Orbitrap mass spectrometry. CoQs were extracted using hexane with the addition of butylated hydroxytoluene to limit oxidation during sample preparation. Chromatographic separation of the analytes was achieved on a Kinetex C18 column with the isocratic elution of 5 mM ammonium formate in 2‐propanol/methanol (60:40) within 4 min. A full MS/all ion fragmentation (AIF) acquisition mode with mass accuracy < 5ppm was used for detection and determination of redox states of CoQ9 and CoQ10 in healthy mice tissues using reduced and oxidized CoQ4 as internal standards. The validated method showed good linearity (r2≥ 0.9991), intraday, inter‐day precision (CVs ≤ 11.9%) and accuracy (≤ ±15.2%). In contrast to existing methods, the current method offers enhanced sensitivity (up to 52 fold) with LOD and LOQ ranging from 0.01–0.49 ng mL−1 and 0.04–1.48 ng mL−1, respectively. Moreover, we evaluated various diluents to investigate bench top stability (at 4°C) of targeted analytes in tissue samples during LC‐MS assay up to 24 h. Ethanol was determined to be the optimum diluent without any significant oxidation of reduced CoQ up to 24 h. The developed method offers a rapid, highly sensitive and selective strategy for the measurement of redox states of CoQs in clinical studies.

Support or Funding Information

University of Texas System (ST: STAR Award), Hyundai Hope on Wheels research program, NIH R01 CA206210‐01, and Cancer Prevention & Research Institute of Texas (CPRIT, DP150061).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Characterization of the secondary structure and protein binding affinity of an intramolecular DNA four‐way junction.
Authors: Smith Andrew , Kebede Yonatan , Moorhead Gaston , Huang Raymond , Bell Anthony Jerome
Published: June 2021

Oligodeoxynucleotides (ODN) offer great promise as antigene and antisense reagents due to their high binding specificity, straight‐forward synthesis and low toxicity. Research shows that ODNs can also target proteins such as the DNA‐binding cytokine, High Mobility Group B1 (HMGB1). HMGB1 was initially classified as a highly abundant architectural nuclear protein. It is now clear that HMGB1 also functions as a redox sensitive damage associated molecular pattern (DAMP) molecule. And several studies link deleterious HMGB1 inflammatory signaling with an array of diseases and immune disorders such as: atherosclerosis, cystic fibrosis, lupus and sepsis. Hence, HMGB1 is gathering a great deal of attention as a biomarker and therapeutic target. We hypothesize that ODNs based on DNA four‐way junctions (4WJs) can be used to target HMGB1. In order to enhance the stability of 4WJs for ex vivo studies, the helical termini of a DNA junction are modified to generate the intramolecular construct, i‐J1. The secondary structure, thermostability and protein binding affinity of i‐J1 are investigated vs. a control 4WJ (J1) and the intramolecular 4WJ, J4. Non‐denaturing gel electrophoresis assays show that i‐J1 possesses a global structural conformation that is analogous to the control 4WJ. Circular dichroism (CD) studies show that the secondary structure of i‐J1 is composed of B‐ and A‐form DNA helices. Moreover, the melting temperature (Tm) of i‐J1 is significantly higher than J1. The Tm of i‐J1 is ~ 30°C higher than J1. Finally, electrophoretic mobility shift assays (EMSAs) show that the HMG protein, HMGB1b, binds i‐J1 with nearly identical affinity to J1. The data clearly shows that the junction lattice of a DNA four‐way junction can be altered to enhance conformational stability and retain protein binding affinity.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
DNA‐binding peptide dendrimer for efficient and selective intracellular delivery
Authors: Kam Antony , Wong Clarence Tsun Ting , Loo Shining , Tam James P.
Published: June 2021

Dendrimeric peptides or peptide dendrimers are branched peptides with multiple peptidyl units. Multiple antigen peptides (MAPs) are examples of dendrimeric peptides first introduced in 1988 by our laboratory as immunogens for producing monoclonal and polyclonal antibodies. We also designed antimicrobial dendrimeric peptides, such as D4R, using a tetrapeptide RLYR which contains a ChC‐motif (cationic‐hydrophobic‐cationic) found in the naturally‐occurring antimicrobial peptides such as tachyplesins and protegrins. Advantages of D4R as a short‐chain, tetra‐branched peptide dendrimer include its short preparation time (a few hours), its polycationic, low membranolytic activity to human red blood cells, and high proteolytic stability. Here, we show that D4R is also a cell‐penetrating and an intracellular DNA‐binding peptide dendrimer. Using solid‐phase synthesis, we exploited different chemistries to attach tags or small molecules to the α‐ or ɛ‐amino groups of lysine to form a tetra‐branched dendrimer with four chains of RLYR. An example is D4R‐f, a C‐terminal 5‐FAM‐labeled D4R which we showed that it can enter living cells through endocytosis‐independent mechanisms as determined by using epi‐fluorescence microscopy. Furthermore, we showed that D4R‐f is distributed in different intracellular organelles during different stages of the cell cycles and colocalizes with nuclear DNA in cells undergoing mitosis. Using agarose gel shift assay, we showed that D4R binds to double‐stranded DNA. Co‐incubation of D4R with DNA showed resistance against DNase‐mediated digestion. The control linear 16‐residue peptide with four tandemly repeating RLYR units was not cell‐penetrating like D4R. Modifying the ChC motifs of the short‐chain peptide dendrimers produced different results, suggesting that the RLYR motif is tunable. Taken together, this study highlights D4R as a prototypic DNA‐binding peptide dendrimer which penetrates into living cells through endocytosis‐independent uptake mechanisms. Our work also suggests the potentials of short‐chain DNA‐binding peptide dendrimers as a lead to design anti‐mitotic agents and a convenient new tool for non‐viral gene delivery.

Support or Funding Information

This research was supported in part by Nanyang Technological University Internal Funding ‐Synzyme and Natural Products (SYNC) and the AcRF Tier 3 funding (MOE2016‐T3‐1‐003).

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Utility of AMP Detection System for Monitoring the Activities of Diverse Enzyme Reactions
Authors: Goueli Said , Hsiao Kevin , Mondal Subhanjan
Published: June 2021

Adenosine monophosphate (AMP) is a key cellular metabolite regulating energy homeostasis and signal transduction. AMP is also a product of various enzymatic reactions, many of which are disregulated during disease conditions. Thus, monitoring the activities of these enzymes is a primary goal for developing modulators for these enzymes. Here, we demonstrate the versatility of an enzyme coupled assay that quantifies the amount of AMP produced by any enzymatic reactions regardless of its substrates. We successfully implemented it to enzyme reactions that use ATP as a substrate (aminoacyl tRNA synthetase and DNA ligase) by an elaborate strategy of removing residual ATP and converting AMP produced into ATP so it can be detected using luciferase/luciferin and generating light. We also tested this assay to measure the activities of AMP generating enzymes that do not require ATP as substrate, including phosphodiesterases (cAMP) and E.coli DNA ligases (NAD+). In a further elaboration of the AMP‐Glo platform, we coupled it to E.coli DNA ligase, enabling measurement of NAD+ and enzymes that use NAD+ like mono‐ and poly‐ADP‐ribosyltransferases. Sulfotransferases use 3′‐Phosphoadenosine‐5′‐phosphosulfate (PAPS) as the universal sulfo‐group donor and Phosphoadenosine‐5′‐phosphate (PAP) is the universal product. PAP can be quantified by converting PAP to AMP by a Golgiresident PAP‐specific phosphatase, IMPAD1. By coupling IMPAD1 to the AMP‐Glo system we can measure the activities of sulfotransferases. Thus by utilizing the combinations of biochemical enzymatic conversion of various cellular metabolites to AMP, we were able to demonstrate the versatility of the AMP‐Glo assay.

Support or Funding Information

The research was supported by Promega Corp.

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.