bluuebunny/crossref_metadata_2025_split huggingface dataset:
Central nervous system 5‐HT plays a role in ventilatory and arousal responses to hypoxia and hypercapnia in spinal cord injured mice
Authors: Qiu Qingchao , Kissane Dylan , Kuhn Donald , Mateika Jason 
Published: May 2022

PurposeThe present investigation was designed to explore the impact of serotonin (5HT) on the arousal and ventilatory response to hypercapnia and hypoxia following spinal cord injury (SCI) in mice.MethodsTelemetry transmitters were surgically implanted in wild type mice (Tph2+/+) (n =7 for SCI, n=7 for Sham) and tryptophan hydroxylase 2 knockout mice (Tph2‐/‐) (n=6 for SCI, n=6 for Sham) to measure electroencephalography, electromyography (EMG) of the genioglossus (GG) muscle, core body temperature and gross motor activity. Following recovery, the Tph2+/+ and Tph2‐/‐ mice were placed in whole body plethysmographs and measures of the ventilatory and arousal response to hypoxia and hypercapnia during non‐rapid eye movement sleep were obtained. Following these measures, a C2 hemi‐section of the spinal cord was completed and the physiological measurements were repeated 4 and 21 days following SCI. The ventilatory data is presented as a fraction of baseline.ResultsThe breathing frequency, tidal volume, and minute ventilation response to hypercapnia was greater in Tph2+/+ compared to Tph2‐/‐ mice at 21 days post SCI (Breathing frequency: 1.37 ± 0.12 vs. 1.02 ± 0.10, p = 0.036, Tidal volume: 1.70 ± 0.21 vs. 0.91 ± 0.09, p = 0.002, Minute Ventilation: 2.87 ± 0.48 vs. 0.93 ± 0.12, p = 0.001). In addition, the tidal volume and minute ventilation response to hypoxia was greater in Tph2+/+ compared to Tph2‐/‐ mice at 21 days post SCI (Tidal Volume: 1.27 ± 0.09 vs. 0.94 ± 0.08, p = 0.009, Minute Ventilation: 1.45 ± 0.14 vs. 0.98 ± 0.09, p = 0.012). The arousal latency to hypercapnia was reduced in Tph2+/+ compared to Tph2‐/‐ mice at 4 days post SCI (16.22 ± 4.15 vs. 73.83 ± 15.78 s, p = 0.013). The number of arousals during exposure to hypercapnia was greater in Tph2+/+ compared to Tph2‐/‐ mice at 21 days post SCI (5.31 ± 0.50 vs. 3.40 ± 0.51, p = 0.021). The magnitude of the GG response to hypercapnia and hypoxia was greater in Tph2+/+ compared to Tph2‐/‐ mice at 21 days post SCI (Hypercapnia: 47.42 ± 10.17 vs. 0.73 ± 0.18, p = 0.012, Hypoxia: 43.82 ± 11.25 vs. 3.30 ± 1.65, p = 0.019). The fraction of episodes in which there was no EMG response to hypercapnia and hypoxia was lower in Tph2+/+ compared to Tph2‐/‐mice at 4 days post SCI (Hypercapnia: 0.43 ± 0.10 vs. 0.92 ± 0.08, p = 0.001 Hypoxia: 0.19 ± 0.12 vs. 0.85 ± 0.15, p = 0.008). The fraction of episodes in which there was no EMG response to hypercapnia was lower in Tph2+/+ compared to Tph2‐/‐ mice at 21 days post SCI (0.19 ± 0.06 vs. 0.79 ± 0.10, p = 0.001).ConclusionThe ventilatory, arousal and GG response to hypercapnia and hypoxia is greater in Tph2+/+ compared to Tph2‐/‐ mice following SCI. Our results suggest that deficiencies in serotonin have a role in regulating respiratory and arousal responses to hypercapnia and hypoxia following SCI.
The Role of Glutamatergic Signaling in Central Noradrenergic Neurons in Respiratory Control
Authors: Chang Yuan , Ray Russell 
Published: May 2022

Central noradrenergic (NA) neurons are key constituents of the respiratory homeostatic network. NA dysfunction is implicated in several developmental respiratory disorders such as the fatal Sudden Infant Death Syndrome (SIDS) and Rett Syndrome, in which abnormal chemosensory function is thought to play a role. However, which NA populations modulate respiratory chemoreflexes and the underlying mechanisms are still not fully understood. Histological evidence suggests that glutamate is co‐transmitted in subsets of brainstem NA neurons, some of which may contribute to regulating chemoreflexes. However, the extent of glutamate co‐transmission in the central NA system remains uncharacterized. Further, it remains unclear what role NA‐based glutamatergic signaling plays in various aspects of respiratory homeostasis.To anatomically map potential glutamate‐expressing NA neurons, we characterized the expression profile of all three known of Vesicular Glutamate Transporters (Vglut1, Vglut2 and Vglut3) in NA neurons by intersectional genetic fate mapping. For each Vglut1/2/3 transporter, acorresponding Cre knock‐in recombinase line was combined with DBH‐p2a_Flpomice. These Vglut1/2/3_Cre; DBH‐p2a_Flpocompound lines were crossed with the RC::F_TdTomato_P_GFPintersectional reporter mice. In each of the three intersectional reporter crosses, NA neurons co‐expressing either Vglut1, Vglut2, or Vglut3 are labeled by green fluorescent protein (GFP) while NA neurons without any Vglut1/2/3 expression are labelled by red fluorescent protein (tdTomato). Our preliminary fate maps, which reflect the cumulative expression profiles of glutamate markers in NA neurons throughout the development and lifetime of the mouse, found that about 80% NA neurons express Vglut2 at some point during their development and posterior medullary NA neurons express Vglut3 as well.Prior studies suggest that Vglut2‐based glutamatergic signaling may play a role in respiratory control. To determine what physiological role, if any, Vglut2‐based glutamatergic signaling may play in adult respiratory homeostasis, we conditionally ablated Vglut2 in central NA neurons by crossing DBH‐Cre/+with Vglut2flox/flox mice. Mutants and sibling controls (6‐8 weeks) were assessed for respiratory function by whole‐body barometric plethysmography. Ventilation and VO2 were assessed under room air (21%O2,79%N2), hypercapnia (21%O2, 74/72/69%N2, 5/7/10%CO2) and hypoxia (10% O2, 90% N2). Our preliminary data indicates that loss of Vglut2 in NA neurons does not significantly impact breathing under room air, hypercapnia, or hypoxia. Thus, our data suggests that Vglut2‐based glutamatergic signaling within the central NA system is dispensable for normal baseline breathing and hypercapnic, and hypoxic chemosensory reflexes.
CD68, CD86 and CD163 Expression Profile in Breast Cancer Molecular Subtypes
Authors: Talaat Iman M. , Elemam Noha M. , Abdullah Hanan W. 
Published: May 2022

Background and aimBreast cancer (BC) is the second most common global cause of cancer deaths among women. Several immune cells are identified in the tumor microenvironment of BC patients, including tumor‐associated macrophages. We aimed at exploring the expression of distinct functional phenotypes using macrophages’ markers, where CD68 is a pan‐macrophage marker, CD86 is a marker expressed in polarized M1 subtype, and CD163 is expressed in M2 polarized subtype.MethodsA retrospective study was performed using 90 formalin‐fixed paraffin‐embedded BC specimens for the immunohistochemical analysis of CD68, CD86 and CD163. Also, an in silico tool, UALCAN, was used on a larger cohort (n=1,081) of BC patients to investigate the expression of these markers. The macrophages’ markers were then associated with the clinicopathological parameters of BC patients. Triple‐negative BC cell line “CAL‐51” and luminal BC cell line “MCF‐7” were used to collect their respective supernatants that were added to THP‐1 derived macrophages. Then CD86 and CD163 were assessed using western blot.ResultsThe pan‐marker of macrophages, CD68, along with the M1 CD86 marker and M2 CD163 marker, showed positive results in all the 90 investigated patients (Figure 1). CD86 expression was significantly associated with body mass index (BMI) and Ki‐67 proliferation marker. On the other hand, CD163 was significantly correlated with tumor size, estrogen, progesterone receptors, and BC molecular subtypes. Moreover, the high expression of CD86 and CD163 showed unfavorable outcome and survival of BC patients. In silicoanalysis revealed a significant increase in the CD86 expression in BC patients, especially in the triple‐negative subtype. Similarly, CD163 expression was found to be higher in the triple‐negative subgroup compared to the luminal group (Figure 2A). Additionally, in vitro work showed that the macrophages induced from the monocytic THP‐1 cell line express high levels of CD163 upon the exposure to conditioned media collected from the luminal BC cell line “MCF‐7”, thus showing M2 phenotype. On the contrary, CD163 expression was reduced upon the exposure to the conditioned media collected from the triple‐negative BC cell line “CAL51”, indicating more M1 phenotype (Figure 2B).ConclusionTumor‐associated macrophages are associated with cancer progression and molecular subtypes. Hence, identifying the macrophages polarization profiles in each molecular subtype might aid their use as potential therapeutic targets.
The Effect of Aerobic Exercise Training on Sympathetic Nervous Activity and Vascular Compliance in Patients with Chronic Kidney Disease
Authors: Jeong Jin Hee , Sprick Justin D. , DaCosta Dana A. , Mammino Kevin , Nocera Joe , Park Jeanie 
Published: May 2022

IntroChronic kidney disease (CKD) is characterized by sympathetic nervous system (SNS) overactivity, which increases risk of cardiovascular (CV) disease and mortality. SNS overactivity can elevate CV risk by impairing vascular compliance and promoting inflammation. Aerobic exercise training exerts CV protective effects and has shown to reduce resting SNS level in populations at heightened CV risk. We tested the hypothesis that aerobic exercise training would reduce resting SNS activity and vascular inflammation and improve arterial compliance in patients with CKD.MethodIn this randomized controlled trial, sedentary individuals with CKD stages III‐IV underwent 12 weeks of aerobic cycling exercise (EX, spinning at 85% of maximal heart rate reserve, n=22) or stretching (ST, n=20, active control intervention). Both interventions were performed 45 minutes/session 3 days/week and matched for duration. Resting muscle sympathetic nervous activity (MSNA) was measured via microneurography, augmentation index (Aix75) was measured by brachial tonometry and vascular cell adhesion protein1 (VCAM) and tumor necrosis factor‐α (TNF‐α) were measured from venous blood samples. All measurements were performed at baseline and following the 12‐week intervention.ResultsThere was a significant group by time interaction in MSNA (p=0.030) with no change in the EX group (32.8 ± 11.9 to 28.1 ± 12.9 bursts/min; p=0.215, n=15), but an increase in the ST group (30.2 ± 11.3 to 37.2 ± 12.9 bursts/min; p=0.042, n=10) after 12 weeks. The similar trend was observed in Aix75 (p=0.031) with no change in EX group (24.9 ± 7.9 to 24.3 ± 9.7; p=0.683, n=22), but an increase in ST group (22.6 ± 7.4 to 26.7 ± 10.5; p=0.012, n=20). We observed no significant change in VCAM and TNF‐α after 12 weeks in either group. The magnitude of change in MSNA was inversely associated with baseline MSNA in EX group (r=‐0.51, p=0.051). In the combined groups, MSNA was positively associated with Aix75 (r=0.38, p=0.06), VCAM (r=0.49, p=0.03) and TNFa (r=0.32, p=0.18) at baseline.ConclusionOur data demonstrates that 12 weeks of cycling exercise has beneficial effects on resting SNS activity and arterial compliance in CKD patients. Specifically, an increase in MSNA and Aix75 observed in the control group over 12 weeks was blunted following exercise training. This sympathoinhibitory effect of exercise training was independent of inflammation and showed greater magnitude in CKD patients with higher resting MSNA.
In Vitro Screening Identifies TRPV4 and PAR1 as Targets for Endothelial Barrier Stabilization in COVID‐19
Authors: Michalick Laura , Mandzimba‐Maloko Bertina , Hamedi Shima , Dohmen Melanie , Brack Markus C. , Schulz Sabrina , Behrens Felix , Simmons Szandor , Müller‐Redetzky Holger , Suttorp Norbert , Kurth Florian , Corman Victor M. , Hocke Andreas C. , Witzenrath Martin , Hippenstiel Stefan , Kuebler Wolfgang M. 
Published: May 2022

Study objectiveEndothelial dysfunction and increased microvascular permeability are hallmarks of severe COVID‐19. At present, the underlying mechanisms of endothelial barrier failure in COVID‑19 remain elusive. Here, we show that increased thrombin activity in plasma from severe COVID‐19 patients activates endothelial protease‐activated receptor (PAR1), which mediates barrier failure by triggering TRPV4‐mediated Ca2+ influx in lung microvascular endothelial cells.MethodsCitrate plasma was sampled as part of the Pa‐COVID‐19 cohort study (ethics approval EA2/066/20) from patients with severe COVID‐19 (high flow O2 or mechanically ventilated; WHO severity score: 5‐7) COVID‑19. Plasma samples were diluted to 10% (v/v) in cell culture medium without FCS and tested for their ability to disrupt barrier integrity of primary human pulmonary microvascular endothelial cells (HPMEC) monolayers by electrical cell‐substrate impedance sensing (ECIS), immunofluorescence for endothelial VE‐cadherin and F‐actin, western blot analyses of PAR‐1 cleavage, and real‐time Ca2+ imaging. Plasma from healthy donors served as control.ResultsCOVID‐19 plasma had elevated thrombin activity while levels of antithrombin III, a key anti‐coagulant with thromboprotective function were decreased. COVID‐19 plasma caused endothelial barrier dysfunction as measured by ECIS and gap formation in HPMEC monolayers. Endothelial barrier disruption and endothelial Ca2+ influx in response to COVID‐19 plasma could be blocked by selective antagonists targeting thrombin (Argatroban), its receptor PAR1 (SCH79797), or TRPV4 (HC‐067047).ConclusionHere, we identify a novel signaling axis involving thrombin, its receptor PAR1, and TRPV4 as mechanism for increased microvascular permeability in COVID‑19. Targeting this signaling axis in endothelial barrier failure may provide a promising adjunctive therapy in COVID‐19.
Direct evidence of a sympathetically‐mediated cardio‐inotropic response to baroreceptor unloading in rats
Authors: Stewart Liam , Wainman Liisa , Ahmadian Mehdi , Duffy Jennifer , Seethaler Rudi , Mueller Patrick J. , Eves Neil , West Christopher R. 
Published: May 2022

RationaleThe baroreflex is a cardio‐autonomic reflex that is responsible for buffering acute oscillations in blood pressure. Contemporary evidence suggests that, when stimulated, baroreceptors activate a neural reflex arc via two efferent pathways: the vascular‐sympathetic arm to control peripheral resistance, and the cardio‐vagal arm to control heart rate. However, since sympathetic post‐ganglionic fibres innervate both the vasculature and left ventricle (LV) it follows that the heart may also contribute to hemodynamic regulation during baroreceptor unloading through alterations in cardiac inotropy, yet to our knowledge this has not been empirically tested using a load‐independent index of LV inotropy.Aim1) To determine whether there is an increase in LV inotropy in response to baroreceptor unloading, and 2) to parse out whether this response occurs via sympathetic activation, parasympathetic withdrawal, or a combination of the two.HypothesesThere will be an increase in LV inotropy in response to baroreceptor unloading, and this response will occur via activation of the sympathetic nervous system.Methods10 male Wistar rats were anesthetized (urethane) and instrumented with a LV pressure‐volume catheter to measure the maximal rate of pressure generation for a given end‐diastolic volume (dP/dtmax–EDV mmHg·s‐1·µl‐1) as a load‐independent metric of cardiac inotropic function. Each rat was then placed in a customized servo‐controlled lower‐body negative pressure (LBNP) chamber that was programmed to reduce mean arterial pressure (MAP) by 10% for 60s to mechanically unload baroreceptors. The protocol was repeated in the same animal following infusions of lactated ringers (control), esmolol (β1 adrenergic receptor antagonist; blocks cardiac sympathetic transmission), atropine (muscarinic receptor antagonist; blocks cardiac parasympathetic transmission), and esmolol+atropine (full cardiac autonomic blockade). Between‐condition differences in LV inotropy were assessed using mixed‐models with Bonferroni corrected post‐hoc pairwise comparisons.ResultsUnder control conditions, dP/dtmax–EDV increased significantly (25.8±4.9 vs 29.9±6.7 mmHg·s‐1·µl‐1; p=0.002) during unloading. Sympathetic and full cardiac blockade significantly reduced baseline dP/dtmax–EDV (10.8±2.1 and 13.5±3.0 mmHg·s‐1·µl‐1, respectively; p<0.001 for both), and abolished the response to baroreceptor unloading (10.6±2.1 and 14.3±4.0 mmHg·s‐1·µl‐1, respectively; p=0.999 for both). Parasympathetic blockade had no effect on baseline dP/dtmax–EDV (26.1±5.5 mmHg·s‐1·µl‐1; p=0.999) and the increase in dP/dtmax–EDV during baroreceptor unloading was maintained (30.5±8.3 mmHg·s‐1·µl‐1; p<0.001).ConclusionThese results provide direct evidence of a sympathetically‐mediated increase in cardiac inotropic function in response to baroreceptor unloading in rats.
Anteriorly Rotated Liver Anomaly in a Prosection Cadaver
Authors: Hurley Mary 
Published: May 2022

The abdominal contents of a 85 year old male cadaver whose cause of death was decompensated congestive heart failure presented with an anteriorly rotated liver that had an enlarged right lobe and much reduced left lobe. The caudate lobe was also much reduced. The gall bladder was oriented vertically, facing the anterior abdominal wall. Other visceral abnormalities included the stomach, which was horizontal in orientation, with the greater curvature facing the anterior abdominal wall and greater omentum shifted to the left. The ascending colon continued beyond the hepatic flexure, and the transverse colon was located in the left upper quadrant. The descending colon was shifted towards the right and the sigmoid colon was enlarged, and it and the sigmoid mesocolon were located in the right lower quadrant. The vasculature of the viscera originated from the unpaired abdominal aortic branches in typical fashion, except that some were of different lengths to reach the organs that they supplied. One such vessel was the proper hepatic artery as it had to traverse the abdominal cavity further horizontally than typical due to the displacement of the liver. The inferior mesenteric artery took a looping path to the right lower quadrant due to the displacement of the sigmoid colon. The middle colic artery branch of the superior mesenteric traveled vertically and to the left to supply the transverse colon located in the left upper quadrant.Literature provides few examples of this anomaly. An autopsy of a 39 year old African American female had similar presentation of the liver and gall bladder but no report of unusual presentation of the colon.(https://www.hindawi.com/journals/crihep/2013/493713/(2013)) It was also reported as a result of a CT scan of an 82 year old Indian male that was performed due to left flank pain (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6159280/(2017)). Noted during exploratory surgery of a 30‐year‐old African American male with a pleuroperitoneal hiatus that also had congenital deformities of the right upper extremity and a club foot, the liver was rotated into the left upper quadrant with a posteriorly placed gall bladder (Diseases of the Chest 29: 583‐4(1956)).
Phenotypic Changes Produced by Endogenous DNA Damage in Yeast Mutants Deficient in Recombination and Base Excision Repair
Authors: Berry Armand M. 
Published: May 2022

DNA is under constant attack by exogenous and endogenous factors. Endogenous sources of DNA lesions include free radicals such as reactive oxygen and nitrogen species (RONS), as well as many naturally occurring enzymatic and chemical processes. To prevent mutations and possibly cell death these lesions must be repaired prior to DNA replication. There are five major pathways that are utilized for repair depending on the type of DNA damage. Eukaryotes utilize two pathways, homologous recombination (HR) and nonhomologous end‐joining (NHEJ), for repair of DNA double‐strand breaks (DSBs). In addition, the cells utilize base excision repair (BER) for repair of damaged or missing bases. Previous work in the lab has shown that HR‐deficient yeast mutant cell cultures exhibit high levels of G2 phase cells during normal growth, without exposure to exogenous DNA damaging agents. Inactivation of DNA damage checkpoint genes, but not spindle checkpoint genes, abolished the high G2 cell phenotype, indicating that the damage checkpoint is persistently activated in the cells. In a screen of yeast mutant library strains deficient in each of the major repair pathways, the high G2 phenotype was observed in HR‐ and BER‐deficient cells, but not in mutants specifically defective in nucleotide excision repair (NER), mismatch repair (MMR) or NHEJ.Experiments performed for the current project have assessed the consequences of inactivation of the HR and BER pathways on yeast cells in more detail. The high G2 cell phenotype was heightened in both diploid HR (rad52) and BER (apn1, ogg1) mutants relative to their haploid counterparts. Expression of DIN1 (RNR3), a DNA damage‐inducible gene, was found to be constitutively induced in the HR mutant cells. Preliminary tests of the role of free radicals in generation of endogenous signaling were performed by overexpression of Yap1p, a transcriptional activator of antioxidant enzyme genes. The high G2 cell phenotype was abolished in ogg1 mutants and strongly reduced in rad52 cells when Yap1p was overexpressed. Current work is focused on (a) analysis of DIN1 promoter activation in BER mutants, (b) assessment of the impact of neutralization of free radicals using chemical antioxidants, and (c) measurement of phosphorylated Rad53 checkpoint protein levels using Western blots to characterize the DNA damage checkpoint signaling response.