bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vanadium complexes inhibit growth of HT‐29 cells via ROS generation
Authors: Moretti Brandon , McCaffrey Vanessa , Rabquer Bradley James 
Published: November 2023

PurposeCancer is characterized by uncontrolled cell proliferation caused by a loss of control of cell cycle growth and division. Many chemotherapeutics have been developed to induce apoptosis or inhibit cancer cell growth. Previous studies have evidenced the efficacy of organometallic compounds, notably cisplatin and its derivatives, in inhibiting tumor growth. Further studies have been conducted with other metal elements to assess their potential as anti‐cancer drugs. One in particular is vanadium, which has been shown to elicit effects via multiple biochemical pathways. We previously synthesized novel vanadium complexes with variable functional groups and found that they were able to inhibit growth in breast (MCF‐7) and colon (HT‐29) cancer cell lines to varying degrees. Here, we hypothesized that these complexes were inducing apoptosis via caspase 3/7‐mediated pathways and inducing cell death by an increase in reactive oxygen species generation.Methods & ResultsHT‐29 cells were used as a model of colon cancer, along with a line of HEK293 cells, which served as a noncancerous model. Previously synthesized vanadium complexes (VCs) with 5‐Br and 3‐OMe functional groups were used as treatments in vitro. A cell proliferation assay was used to assess HEK293 growth inhibition after treatment with each VC. Results showed 55.2% (p<0.05) and 24.6% (p<0.05) growth inhibition for 0.5mM 5‐Br and 3‐OMe VCs, respectively, which is comparable to previously presented results with the HT‐29 cells. An intracellular ROS generation assay was used with both HT‐29 and HEK293 cell lines after being treated with 0.25 mM 5‐Br and 3‐OMe VCs for 4, 24, 48, and 72‐hour incubation periods. For the HT‐29 cells, there were no significant increases in ROS generation after 4, 24, or 48‐hour incubation periods with either treatment. After 72 hours, however, the 5‐Br‐VO2 yielded a 51.3% (p<0.05) increase in intracellular ROS generation compared to the ligand control, and the 3‐OMe‐VO2 yielded a 46.0% (p<0.05) increase. For the HEK293 cells, there was likewise no significant increase in ROS generation after 4‐hour incubation periods, but there was a 44.1% (p<0.05) increase in ROS generation after 24‐hour incubation with the 5‐Br‐VO2 alone. There were no significant increases in ROS generation after the 24‐hour incubation period in the HEK293 cells. Finally, a caspase 3/7 apoptosis detection assay was also used to determine caspase pathway activation. Compared to the cisplatin positive control, the 5‐Br‐VO2 treatment yielded no measurable caspase activation in the HT‐29 cells after 16 and 24 hours of incubation.ConclusionWe found that VCs were able to effectively inhibit HT‐29 growth through likely intracellular generation of ROS, rather than through caspase activation of apoptosis.Support or Funding InformationHewlett‐Mellon Fund for Faculty Development at Albion College
Intermittent Hypoxia Decreases Baroreflex Sensitivity in Healthy Humans
Authors: Scruggs Zachariah M , Newhouse Lauren P , Joyner Michael J , Curry Timothy B , Limberg Jacqueline K 
Published: November 2023

BackgroundPatients with sleep apnea experience repeated, intermittent hypoxic exposures during sleep and are at increased risk of developing hypertension. The mechanisms that contribute to high blood pressure in these patients are not completely understood. In this context, we sought to examine the effect of intermittent hypoxic exposures on baroreflex sensitivity and blood pressure. We hypothesized 3‐hours of intermittent hypoxia would result in a decrease in baroreflex sensitivity in healthy adults. We further hypothesized any decrease baroreflex sensitivity would be related to an increase in blood pressure following intermittent hypoxia.MethodsSix (5M/1F) young healthy, non‐obese, subjects without sleep apnea completed 3‐hours of intermittent hypoxia. Intermittent hypoxia consisted of 25‐second exposures to hypoxic gas (0.05 FiO2) separated by 2 minutes of room air breathing, resulting in 25‐hypoxic events per hour in which oxygen saturation (SpO2) was significantly reduced (Normoxia: 97%, Hypoxia: 89%, p<0.01). Beat‐to‐beat heart rate (electrocardiogram) and blood pressure (finger photoplethysmography) were measured continuously. Spontaneous cardiac baroreflex sensitivity was determined using the sequence method (WinCPRS) and data are reported from 10‐minutes of quiet, normoxic rest before and after the intermittent hypoxia protocol.ResultsWe observed a significant reduction in spontaneous cardiac baroreflex sensitivity to falling pressures (“down‐down”) following intermittent hypoxia (Control=22±2, IH=15±2 ms/mmHg; p=0.02). No change in baroreflex sensitivity to rising pressures (“up‐up”) was observed (Control=25±2, IH=20±6 ms/mmHg; p=0.41). A relationship between baroreflex sensitivity and mean arterial blood pressure was observed, such that a reduction in baroreflex sensitivity tended to be related to an increase in blood pressure (“down‐down”: R=−0.45, p=0.14; “up‐up”: R=−0.54, p=0.07).ConclusionsIntermittent hypoxia results in a decrease in baroreflex sensitivity, which is related to an increase in blood pressure. These data may have important implications for mechanisms contributing to the risk of hypertension in individuals with sleep apnea.Support or Funding InformationDK90541 (MJJ), HL120570 (JKL)
Localization of corticotropin releasing factor receptor 2 (CRFR2) in the nucleus tractus solitarii (nTS)
Authors: Ruyle Brian C. , Callanan Gabrielle F. , Haney Megan M. , Coldren K. Max , Heesch Cheryl M. , Hasser Eileen M. 
Published: November 2023

The paraventricular nucleus of the hypothalamus (PVN) is required for full expression of cardiorespiratory responses evoked by peripheral chemoreflex stimulation. However, the efferent pathways from the PVN that contribute to chemoreflex responses are not fully understood. We have previously shown that hypoxia activates (Fos‐immunoreactivity; IR) PVN neurons that project to the nTS, and a large proportion of these neurons are CRH‐IR. Activation of CRF2 receptors (CRFR2) in the nTS elicits cardiovascular responses, and thus we considered that CRH PVN neurons may influence nTS neuronal activity and cardiorespiratory effects of chemoreflex activation through binding of CRH to CRFR2s. Immunohistochemistry was performed to determine the distribution of CRFR2 in the nTS. CRFR2‐IR was not identified in neurons or glia but was localized in fibers throughout the caudal, postremal and rostral nTS. CRFR2 formed close appositions on dendrites (displaying MAP2‐IR) of nTS catecholaminergic (tyrosine hydroxylase; TH‐IR) neurons and a portion of CRFR2 was colocalized with the synaptic vesicle protein Synaptophysin (Syn). An AAV viral vector expressing mCherry under the promoter CAMKII was microinjected into the PVN and mCherry containing fibers in nTS were evaluated. Terminals in the nTS originating from the PVN (mCherry) also exhibited colabeling with Syn and appeared to make close appositions on TH‐IR nTS neurons. Interestingly, CRFR2‐labeled fibers were colocalized extensively with oxytocin‐IR that also exhibited Syn‐IR. These results suggest that CRH, likely from the PVN, may bind to presynaptic CRFR2s located on oxytocin‐containing fibers to modulate the activity of catecholaminergic nTS neurons and influence cardiorespiratory regulation.Support or Funding InformationNIH RO1 HL98602
Higher Cell Growth/Viability Accompanied by Reduced Myosin Heavy Chain Expression in Skeletal Muscle Cells Derived from Severely Obese Type 2 Diabetic Humans
Authors: Turner Kristen D , Zou Kai , Hinkley Matthew , Park Sanghee , Zheng Donghai , Houmard Joseph 
Published: November 2023

Skeletal muscle metabolism is markedly impaired in a state of severe obesity (BMI ≥ 40 kg/m2) and oftentimes worsened with Type 2 Diabetes. Such impairments have been demonstrated through our previous findings in vitro, in which both glycolytic and oxidative metabolism are reduced in skeletal muscle from severely obese (SO) as well as severely obese type 2 diabetic individuals (T2D). These data suggest that such metabolic differences observed may be intrinsic to skeletal muscle. However, we have not yet provided empirical evidence to show whether these differences could be due to other physical properties associated with these muscle cells (i.e., viability, morphology, muscle cell machinery). Thus, the purpose of this study was to examine the growth/viability of human skeletal muscle cells (HSkMCs) derived from SO and T2D individuals in comparison to lean individuals. This study also determined whether mature myotubes exhibited differences in myosin heavy chain (MYHC) expression among groups. We hypothesized that skeletal muscle cells derived from T2D donors would exhibit lower cell viability and MYHC expression in comparison to their lean and SO counterparts. Interestingly, colorimetric metabolic activity assays revealed myoblast cell viability to be significantly higher in myoblasts derived from T2D donors at 24, 48 and 72 hours post‐plating. However, immunocytochemical staining of MYHC (performed on days 6–7 of differentiation) illustrate considerably less MYHC expression in mature myotubes derived from T2D donors. These findings demonstrate that severely obese type 2 diabetic individuals exhibit critical defects in both structural and functional properties of skeletal muscle that are retained at the cellular level, and that such differences may not always be apparent with severe obesity alone.Support or Funding InformationThis study was supported by the National Institute of Health (DK 56112)
The Enhanced CO2 Chemoreflex is Associated with Increased Number of CO2‐activated Orexin Neurons in the Lateral Hypothalamus in Spontaneously Hypertensive Rats (SHRs)
Authors: Li Aihua , Nattie Eugene , Roy Sarah 
Published: November 2023

Activation of central chemoreceptors by CO2 increases arterial blood pressure (ABP), sympathetic nerve activity (SNA), and breathing. Experiments using SHRs, a well‐established neurogenic hypertensive model, have shown that the high ABP is associated with elevated SNA and peripheral chemoreflexes, and an impaired baroreflex. We have showed that: 1) SHRs have an age‐dependent increase in CO2 chemoreflex and ABP; 2) the increased CO2 chemoreflex and ABP are measureable in juveniles (P28–50); 3) the enhanced CO2 chemoreflex persists while peripheral chemoreceptors were inhibited by hyperoxia indicating an important role for central chemoreflex in neurogenic hypertension; and 4) blocking orexin receptors with a dual orexin receptor antagonist, Almorexant (Almxt), can normalize the enhanced CO2 chemoreflex and significantly lower high ABP in SHRs. In this study, we evaluated CO2‐activated c‐fos expression in orexin neurons in both hypertensive (SHRs) and normotensive control (WKY) rats, and hypothesized that the enhanced CO2 chemoreflex observed in SHRs is associated with increased number of CO2‐activated c‐fos expressing orexin neurons in the lateral hypothalamic area (LHA). The rats were exposed to 7%CO2 for 1.5hr, and sections of LHA were double stained for c‐fos and orexin‐A. The Stereo Investigator System was used for the cell counts. The results show that in the LHA, SHRs have: 1) more orexin‐containing neurons (~28%), similar as some recent reports, and 2) more CO2‐induced c‐fos and orexin double‐expressing neurons (~71%) than that of age‐matched normotensive WKY rats. We conclude that the enhanced CO2 chemoreflex in SHRs is associated with the overactive orexin system, and modulation of this overactive orexin system and CO2 chemoreflex could be beneficial in treating neurogenic hypertension.Support or Funding InformationNIH HL 28066
Characteristics in the Vulnerability of the Respiratory Neural Control System During a Critical Window of Postnatal Development
Authors: MacFarlane Peter Mathew , Mayer Catherine Ann 
Published: November 2023

Prior studies have demonstrated the existence of a critical window of neurochemical expression that occurs in the brainstem at approximately 12 days of postnatal (P12) age in the rat. The critical window is characterized by changes in the expression of various neurotransmitters, receptors, trophic factors, and metabolic enzymes in various brainstem respiratory control regions. Presumably these changes represent important neurodevelopmental events necessary for appropriate maturation of the cardio‐respiratory control system. However, studies from our lab have begun to demonstrate the critical window is a period of development during which the respiratory control system exhibits a heightened vulnerability to environmental challenges. For example, five days of sustained hypoxia exposure (SH: 11% O2) between P11–15 days, which encompasses the P12 critical window, abolished the ventilatory response to acute hypoxia (HVR (delta baseline): 0.63 ± 0.31 ml/g/min) compared to age‐matched rats raised in normoxia (0.12 ± 0.45 ml/g/min). The absence of a HVR in these rats was associated with an unexpected and substantial degree of mortality that occurred ~3 days later. These effects were unique to the critical window as neither younger (P1–5) or older (P21–25) rats were affected by the same exposure to SH. We have also shown the critical window appears to be an important stage of brainstem neurodevelopment because it is represented by a transient surge in constitutive expression of brainstem mRNA for NeuroD1 and CyclinB2. However, SH between P11–15 reduced their expression (NeuroD1: 0.66 ± 0.11; CyclinB2: 0.74 ± 0.14 fold‐change from normoxia control rats), indicating a major and potentially fatal disturbance in brainstem mechanisms of neurodevelopment. The critical window of development was also characterized by a transient increase in the constitutive expression of brainstem TNFα mRNA, which was further increased by SH exposure (1.47 ± 0.09 fold‐change from control). Further, SH also decreased serotonin (5‐HT) levels specifically within the dorsal motor nucleus of the vagus (DMNV) and nucleus of the solitary tract (nTS). We speculate that SH exposure interferes with key neurodevelopmental events, ultimately leading to a lethal disturbance in brainstem neurochemistry within distinct (cardio)–respiratory control regions and may involve a mechanism associated with an aberrant cytokine response. These data could contribute to our understanding of the pathways involved in the brainstem neurochemical abnormalities observed in Sudden Infant Death Syndrome (SIDS).Support or Funding InformationDepartment of Pediatrics, Rainbow Babies & Children's Hospital, Case Western Reserve University
Body Mass Estimation from the Knee: Forensic Applications
Authors: Squyres Nicole , Ruff Christopher 
Published: November 2023

The estimation of living body mass from skeletal material can be a useful component of a forensic profile. Previously, forensic anthropologists have generally used body mass estimation equations derived either from the femoral head or from a combination of bi‐iliac breadth and stature. However, these equations were originally generated for use in archaeological or paleontological contexts, and therefore may not perform as well in modern sedentary populations. In particular, these equations may significantly underestimate body mass in overweight and obese individuals, which increasingly account for a greater percentage of living populations.Here, we present new body mass estimation equations derived from measurements of the knee in a modern sample of known body mass. This reference sample consisted of 110 living subjects who participated in the Baltimore Longitudinal Study of Aging. Mediolateral breadth measurements of the distal femur and proximal tibia were taken from anteroposterior radiographs of the knee, and used with recorded body weight to develop prediction equations. We compare the results from equations derived from the entire reference sample with equations derived from a sample that excludes obese individuals (BMI>30). We also compare equations derived from youngest recorded body mass with equations derived from older body mass recorded at the time of x‐ray.R square, % standard error of the estimate, and % prediction errors are minimized in equations that use youngest recorded body mass and exclude obese individuals. Although body mass for obese individuals is underestimated by all equations, it is best approximated by equations derived from the older recorded body mass that include obese individuals. This type of equation also provides very good estimates of body mass for overweight individuals (25<BMI<30). All equations overestimate body mass to some extent in normal weight individuals, but equations derived from young adult body mass excluding obese individuals perform best in this group. Comparison with other studies suggests that certain of these equations may better approximate body mass in obese and overweight individuals than previously used equations.Our results indicate that, due to increasing rates of obesity in modern societies, body mass estimation equations designed for paleontological use should be applied with caution in the forensic context. Equations derived from modern samples with a greater proportion of overweight and obese individuals will perform better in such cases.
Using Novel Methods to Visualize Jaw Muscle Biomechanics and its Significance for the Evolution of the Avian Feeding Apparatus
Authors: Spates Anthony T , Cost Ian N , Sellers Kaleb C , Middleton Kevin M , Holliday Casey 
Published: November 2023

The avian feeding apparatus is a derived system of bony linkages spanned by numerous jaw muscles in a complex 3D environment. Tracking the evolution of jaw muscles among different clades of birds and their extinct dinosaur relatives remains challenging because of this complexity. Here we introduce novel means of mapping 3D jaw muscle resultants in ternary space to seek patterns in the form, function and evolution of avian head and determine the origins of cranial kinesis. For this pilot project, we built 3D biomechanical models of four taxa of birds (ostrich, chicken, hawk, and parrot) and their extinct relative Tyrannosaurus thus spanning a range of cranial morphology, feeding function, and phylogeny. Specimens were microCT‐scanned using normal and contrast enhanced methods, muscles were dissected and physiological cross sectional areas were measured to determine muscle forces. Muscles were then reconstructed in the models and 3D lever analysis was undertaken using BoneLoad and other computational tools to determine 3D muscle resultants, bite forces and joint forces. 3D muscle resultants were then plotted in a ternary space to illustrate the variation in positions and magnitudes of the different jaw musculature. Our findings show many new patterns in avian jaw muscle anatomy and function including: 1) evolutionary convergence in orientation, position, and function of non‐homologous temporal muscles between ostrich and other taxa, 2) Chicken jaw muscles occupy a small, primarily vertically‐oriented portion of the available morphospace whereas the muscles of the parrot occupy a far broader and diverse morphospace reflecting their highly dexterous feeding apparatus, and 3) Protractor muscle resultants vary considerably among the taxa sampled suggesting different capacities for palatal mobility and cranial kinesis. These findings highlight the comparative power of these new methods for visualizing jaw muscle functional morphology in birds and other vertebrates and will offer significant new direction in comparative morphometric, biomechanical and evolutionary analyses.Support or Funding InformationThis work was funded by NSF IOS 1457319, the University of Missouri Express Program and the University of Missouri Honors Program.
The chromatin remodeling complex SWI/SNF is a master regulator of meiotic splicing in Saccharomyces cerevisiae
Authors: Venkataramanan Srivats , Douglass Stephen , Galivanche Anoop Raj , Johnson Tracy 
Published: November 2023

Despite its relatively streamlined genome, there are important examples of regulated RNA splicing in Saccharomyces cerevisiae. One of the most striking is the splicing of meiotic transcripts. At the onset of meiosis, Saccharomyces cerevisiae, like other eukaryotes, undergoes a dramatic reprogramming of gene expression. This includes regulated transcription and splicing of a number of meiosis‐specific transcripts. Splicing of a subset of these is dependent upon the meiosis‐specific splicing activator Mer1. Here we show a crucial role for the chromatin remodeling complex Swi/Snf in meiotic regulation of splicing. We find that the complex affects meiotic splicing in multiple ways. First, meiosis‐specific downregulation of Snf2, the ATPase subunit of Swi/Snf, regulates the subsequent downregulation of ribosomal protein genes (RPGs), RPGs are enriched in introns, and are highly transcribed. Their downregulation leads to the redistribution of spliceosomes from this abundant class of intron‐containing RNAs to Mer1‐regulated transcripts, which otherwise have poor affinity for the spliceosome. Secondly, expression of Mer1 itself is absolutely dependent on Swi/Snf—Snf2 is poised at the Mer1 promoter, and the timing of Snf2 downregulation allows elegant coordination of these mechanisms. This precisely timed meiotic regulation of Snf2 involves co‐ordination of regulated transcription, translation, protein acetylation and turnover. Hence, the Swi/Snf complex directs the regulated splicing of meiotic genes, establishing it as a master regulator of meiotic splicing in Saccharomyces cerevisiae. Moreover, meiosis serves as an elegant example of a poorly understood, but undoubtedly important general regulatory mechanism employed by cells, whereby redistribution of limiting gene‐regulation machineries to different classes of targets serves as an adaptive strategy in response to environmental changes.Support or Funding InformationNIH GM05474NIH P50 GM085764Whitcome Pre‐Doctoral Fellowship in Molecular Biology.