bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Metformin and Quercetin on the Thermogenesis and Muscle Metabolism of Piglets
Authors: Huang Yan , Wang Yongjie , Tsai Tsungcheng , Ge Jing , Shelby Sarah , Morse Palika D.
Published: May 2022

Metformin is usually used to treat type 2 diabetes, and it is also known to have beneficial effects on body weight and composition. However, the mechanism of its function has not been clarified yet. The aim of this study is to investigate the effects of metformin on the thermogenesis, muscle metabolism, and muscle fiber type of newborn piglets. Total 24 newborn piglets were randomly divided into 4 groups: control group (C, n=6) with no treatment until weaning; Metformin group (M, n=6) with 50mg/kg metformin until weaning; Quercetin group (Q, n=6) with 50mg/kg quercetin until weaning; Metformin + Quercetin group (MQ, n=6) with 50mg/kg metformin + 50mg/kg quercetin until weaning. During the weaning, the surface and rectal temperatures were recorded at 0, 1, 2, 4, 7, 14, 21d. After weaning, all the piglets were fed with the same nursery diet for 6 weeks. After 6 weeks of the nursery, all the piglets were slaughtered, and the longissimus dorsi muscle of each pig was collected to determine gene expression. The results showed that the surface temperature of C group was higher than M, Q, and MQ groups at day‐21 (P<0.01, Figure 1), and rectal temperatures of M, Q, and MQ groups were higher than C from day‐1 to day‐21 (P<0.05, Figure 2). The gene expression of UCP3 and SLN in the M group was higher than C and Q (P<0.05, Figure 3). The MyHC I expression of the MQ group was higher than the C group (P<0.05, Figure 3). The results indicate that feeding metformin and quercetin during weaning increased the rectal thermogenesis and impacted the gene expression related to muscle metabolism and muscle fiber type.
Examining the Plasticity of the Dive Response in Relation to Dive Behavior of Northern Elephant Seals
Authors: Hannah Shawn M. , Williams Cassondra L. , Hindle Allyson G. , Cooley Lauren A. , Ponganis Paul J. , Horning Markus , Klinck Holger , Costa Daniel P. , McDonald Birgitte I.
Published: May 2022

Searching and capturing prey are extraordinary challenges for marine mammals, as they must actively hunt during breath‐hold dives. This challenge is conquered by the dive response (the decreased heart rate and increased peripheral vasoconstriction associated with a breath hold), which lowers the rate of oxygen consumption and prolongs the duration of aerobic metabolism. The dive response is dynamic and potentially influenced by dive duration, depth, anticipation, and exercise. However, it is still unknown how these influences interact with each other to facilitate oxygen management pre‐ and post‐dive, during different dive phases, and at fine scale. We studied the dive response of one of the deepest diving marine mammals, the northern elephant seal (Mirounga angustirostris) across three years (2018, 2019, 2021) to determine interactions between these behavioral and physiological factors. Using a biologger that records electrocardiogram data (50‐100 Hz) and a Daily Diary time‐depth‐recorder that records acceleration and depth, we calculated heart rate, stroke rate, and minimum specific acceleration (MSA) in 7 seals in dives as deep as 460m. We examined the influence of dive depth, duration, and activity (MSA) on dive heart rate, pre‐ and post‐dive heart rate, and heart rate during different dive phases and at fine scale. We recorded heart rates as low as 20 bpm during natural dives, with the average heart rate at depth being 48.91 ± 25.93 bpm. The heart rate rapidly drops at the start of dives from ~100‐120 bpm to ~40‐50 bpm and continues to decline as the seal passively drifts to depth. At the bottom seals tend to stroke and glide while maintaining a relatively stable heart rate. On ascent heart rate gradually increases as the seals stroke and glide to the surface. We see a drastic increase in heart rate just before seals surface, likely to maximize offloading of carbon dioxide and onloading of oxygen upon surfacing. Our preliminary results reveal that both dive depth and MSA influence the dive heart rate at fine scale intervals of 20 s within the dive. These results suggest that the seals actively regulate their oxygen during dives. Our results will connect dive behavior and the dive response to understand how marine mammals perform deep‐dives while actively searching and capturing prey.
Distinct Mechanisms of Morphine Tolerance in Enteric Neurons and Dorsal Root Ganglia Neurons: Role of β‐arrestin‐2
Authors: Muchhala Karan H. , Akbarali Hamid I.
Published: May 2022

Chronic use of mu‐opioid receptor (MOR) agonists, such as morphine, for pain management can lead to the rapid development of analgesic tolerance. In contrast, tolerance to morphine effects in the gastrointestinal tract develops at a different rate. This can limit the therapeutic utility of morphine as the undesired gastrointestinal effects can persist even in the absence of analgesia. It is unclear if the discrete rates of morphine tolerance are due to different underlying mechanisms. β‐arrestin‐2 is a multi‐functional protein implicated in the mechanism of antinociceptive tolerance to opioids. We have recently shown that morphine tolerance in dorsal root ganglia nociceptive neurons is mediated via two distinct mechanisms that are dependent on the duration of drug exposure: a β‐arrestin‐2‐dependent mechanism for short‐term (15‐18 hours) tolerance and a β‐arrestin‐2‐independent mechanism for long‐term (7 days) tolerance (Muchhala et al., 2021, European Journal of Pharmacology). In the gastrointestinal tract, myenteric plexus neurons regulate intestinal motility. However, it is not clear if morphine engages the same molecular mechanisms for tolerance development in myenteric plexus neurons and dorsal root ganglia neurons. Therefore, in the present study we investigated the role of β‐arrestin‐2 in the development of morphine tolerance in myenteric plexus neurons of the mouse ileum. Here, we used whole‐cell patch clamp electrophysiology to examine morphine tolerance in individual ileum myenteric plexus neurons treated with 10 µM morphine for 15‐18 hours or isolated from mice treated with morphine for 7 days. Acute 3 µM morphine significantly increased the threshold to fire action potentials in naïve myenteric plexus neurons. However, this effect was not observed in wild‐type neurons exposed to morphine for 15 ‐18 hours or isolated from mice treated with morphine for 7 days, indicating the development of tolerance. Furthermore, genetic deletion of β‐arrestin‐2 did not prevent the development of morphine tolerance in ileum neurons. In contrast, Bisindolylmaleimide XI, a selective protein kinase C inhibitor, reversed tolerance in ileum myenteric plexus neurons exposed to morphine in vivo for 7 days. In these neurons acute 3 µM morphine significantly increased action potential threshold. Thus, unlike dorsal root ganglia neurons, morphine tolerance in myenteric plexus neurons does not utilize β‐arrestin‐2. These findings reveal a potential mechanism for the differences in the rates of tolerance to morphine and highlight the need to investigate tolerance mechanisms for mu‐opioid analgesics in different tissues/neurons. These results also indicate that mu‐opioid analgesics that preferentially signal through G‐proteins over β‐arrestin‐2 i.e. biased agonists, such as Oliceridine, may induce tolerance in the ileum.
Rare Presentation of Left‐sided Thyroglossal Duct: A Case Report on Embryological Persistence
Authors: Kim Min Young , Arapovic Avianna E. , Geloian Gorune , George Sarah , Shafer Corey , Barremkala Malli
Published: May 2022

Thyroglossal duct (TGD) plays an important role in guiding the embryonic development and migration of the thyroid gland down the midline of the trachea. By the tenth week of gestation, TGD is completely obliterated with the thyroid gland in its proper position. In about 7% of the population, TGD persists and forms a thyroglossal duct cyst (TGDC) within the midline of the pretracheal neck region and often presents as the most common congenital midline neck mass. A rare finding of TGD from posterior base of the tongue to left‐lateral pyramidal lobe, outside its normal midline pathway, was observed in a 92‐year‐old male during routine cadaver dissection of first year medical student’s curriculum at Oakland University William Beaumont School of Medicine. Upon further inspection of the thyroid, there was no evidence of hyperplasia or lesion in the thyroid or the thyroglossal duct itself. The thyroid and associated structures were studied by first year medical students during dissection in 25 formalin fixed cadavers (13 male, 12 female, average age of 76‐years‐old). Four of the 25 cadavers did not present with a thyroid due to previous thyroidectomy. The pyramidal lobe was observed in four of the 25 cadavers (19.05%), and a thyroglossal duct was observed in 3 of the 4 cadavers in the pyramidal lobe subgroup. Within this subgroup, only one cadaver displayed a left‐sided thyroglossal duct. Currently, clinical literature suggest findings of TGDCs in four general regions of intralingual, suprahyoid, thyrohyoid, and suprasternal, but all within the midline pathway of TGD. This case finding reinforces the importance of CT scanning when treating patients with TGDC by surgical removal.
The Ketogenic Diet Impairs Mitochondrial Function in Hearts of Male and Female Mice
Authors: Locke Erica J. , Vinovrski Madison F. , Walborn Luca , Schreffler Ryan , Knappenberger Mya A. , Sprankle Kenyon W. , Kolwicz Stephen C.
Published: May 2022

Ketone bodies have been identified as an important fuel source during physiological and pathological stress. During exercise, augmenting ketone body metabolism in the skeletal muscle may enhance exercise performance while targeting ketone body metabolism in cardiac disease may improve cardiac function. These provocative, yet still debated, findings may promote the consumption of the ketogenic diet (KD) as a method to increase ketone body availability. Since the KD is a high‐fat, low carbohydrate diet, this dietary strategy has the potential to have untoward effects on the heart. Therefore, the purpose of this study was to evaluate the effects of short‐term consumption of the KD on cardiac mitochondrial function. A secondary objective was to evaluate potential sex differences in response to the KD. Male (n=9) and female (n=11) mice at four‐months of age were randomly assigned to a standard chow or KD (90% fat, 9% protein, 1% carbohydrates) group for 6 weeks. Body weight (BW) was obtained weekly. Glucose and ketone bodies were measured at the end of the dietary intervention via hand‐held meters. After 6 weeks, mitochondria were isolated from all hearts and respiration was assessed with an oxygen electrode system. During the first week, Male‐KD lost 2.5±1.5% of initial BW compared to an increase of 0.3±1.5% of initial BW for Male‐Chow. By the third week, both Male‐KD and Male‐Chow gained BW at a similar rate until the end of the study. In contrast, Female‐KD mice gained BW throughout the 6 weeks and the relative increased compared to baseline was approximately 1.7‐2.0‐fold greater than Female‐chow. Serum ketone bodies were significantly increased in both Male‐KD and Female‐KD mice compared to chow fed groups (Male‐chow, 0.33±0.05 vs. Male‐KD, 0.66±0.10 mM, P<0.05; Female‐chow, 0.33±0.02 vs. Female‐KD, 0.66±0.11 mM, P<0.05). There were no significant sex differences in serum ketone bodies or glucose. State 3 respiration with succinate + ADP was ~35% lower in both male and female KD groups (Male‐chow, 236±14 vs. Male‐KD, 148±11 nmol/min/mg, P<0.05; Female‐chow, 186±22 vs. Female‐KD, 133±10 nmol/min/mg, P=0.08). State 3 respiration with pyruvate/malate + ADP were ~30% lower in both Male and female KD groups (Male‐chow, 157±18 vs. Male‐KD, 105±10 nmol/min/mg, P=NS; Female‐chow, 138±22 vs. Female‐KD, 81±8 nmol/min/mg, P=0.06). No statistically significant sex differences in mitochondria function were noted. In summary, 6‐weeks of KD results in sex differences in patterns of weight gain as male mice experience a transient weight loss and females gain weight throughout the study period. Despite the difference in weight gain, hearts from both males and females fed the KD have similar decrements in mitochondrial function. In conclusion, these findings suggest that the KD may negatively affect cardiac mitochondria and caution against the short‐term use of KD.
The effect of the iron chelator Deferasirox in combination with Cisplatin chemotherapy against lung carcinoma
Authors: Rodriguez Torres Priscilla M. , Perez Daraishka , Ferrer Yancy , Delgado Yamixa
Published: May 2022

The preferred treatment for patients with lung carcinoma (LC) is platinum‐based regimens, eg., Cisplatin (CisPt). Unfortunately, despite improvements in LC outcomes, many of these tumors metastasize and develop resistance against such Pt‐drugs, inducing abysmally low survival prognosis. Due to this, there is an urgent need to develop alternative therapies for LC mostly focused on overcome or diminish chemoresistance and inhibit the metastatic spread. FDA‐approved drugs which target cancer metabolic pathways are considered as repurposing drugs that could diminish these adverse effects. Deferasirox (Def), an FDA‐approved iron chelation therapy, is a drug under study for cancer therapy due to iron plays a key role in cell growth and energy production in cancer. Herein, we determined the effect of deferasirox (Def) alone and in combination with CisPt on the genes related to chemoresistance and metastasis in LC cells. Viability assay results showed that Def has synergistic cytotoxic effects in combination with CisPt after 24 h of incubation in A549 LC cells. qPCR gene expression studies showed that Def induced a significant downregulation of EGFR, VEGF, MMP9, Pgp, P53, NDRG1, CHD4 genes in A549 cells. In addition, we determined that Def induce the production of reactive oxygen species in LC. Furthermore, in in vivo studies performed in Lewis Lung Carcinoma mouse model, Def co‐administered with CisPt showed tumor size reduction. The results obtained from this study will impact the field of lung cancer therapy adding knowledge on the Def cellular mechanisms and genetic regulation against chemoresistance and metastasis processes.
Ablation of Na+/H+ exchanger‐3 prevents tissue iron loading in the Hfe mouse model of hereditary hemochromatosis
Authors: Azucenas Corbin R. , Bonamer John P. , Stone Sydney L. , Ruwe T Alex A. , Shawki Ali , Mackenzie Bryan
Published: May 2022

Several common hereditary disorders are associated with toxic iron overload which leads to liver cirrhosis, cardiomyopathy, and endocrine disorders. Hereditary hemochromatosis arises from mutations in the genes coding for any of several proteins involved in iron sensing (e.g. Hfe), hepcidin production (e.g. hemojuvelin), or hepcidin action, resulting in elevated iron absorption relative to the iron need. Divalent metal‐ion transporter‐1 (DMT1) is a H+‐coupled Fe2+ transporter and the principal or only mechanism by which nonheme iron is taken up at the intestinal brush border [Shawki A et al (2015) Am J Physiol Gastrointest Liver Physiol 309, G635–G647]. DMT1 is a validated therapeutic target in treating iron overload. We have shown that Na+/H+ exchanger‐3 (NHE3) is required for adequate iron absorption, via its physiological role in generating at the intestinal brush border an acidic microclimate that energizes DMT1‐mediated H+‐coupled Fe2+ transport [Shawki A et al (2016) Am J Physiol Gastrointest Liver Physiol 311, G423–G430], so we have explored here the contribution of NHE3 to pathological iron loading. We tested the hypothesis that NHE3 activity is necessary for pathological iron loading. We examined the effect of ablating the SLC9A3 gene coding for NHE3 in the Hfe mouse model of hereditary hemochromatosis. We measured tissue iron levels, hematological and blood‐iron variables, and the hepatic expression of Hamp1 (coding for hepcidin) by using qPCR in male and female FVB/N mice, age ≍ 120 d, fed a normal diet (NIH‐07). We examined four genotypes in both sexes: wildtype mice, NHE3 knockout (NHE3−/−), Hfe knockout (hemochromatosis disease model, Hfe−/−), and double knockout (NHE3−/− | Hfe−/−) (n = 12–26 mice per group). We chose α = 0.05, and analyzed our data (mean, SD) by using multifactorial ANOVA. We found that ablation of NHE3 prevented the liver iron loading characteristic of the Hfe−/− mouse model, an effect that was independent of sex. We observed a similar effect on iron loading in the spleen. Ablation of NHE3 produced no sign of overt anemia. Hepatic expression of hepcidin was depressed in NHE3−/− and in Hfe−/− mice relative to wildtype mice, and remained low in the NHE3−/− | Hfe−/− mice, providing a plausible explanation for the observation that, despite correction of the tissue iron levels in NHE3−/− | Hfe−/− mice, iron levels remained high in the readily accessible serum iron pool (typically 0.1% of total body iron). We conclude that ablation of NHE3 prevents pathological tissue iron loading in the Hfe mouse model of hemochromatosis. Pharmacological blockade of NHE3 may offer a means of inhibiting iron absorption in hereditary hemochromatosis.
PRMT5 regulates lipid metabolism in skeletal muscle via epigenetic suppression of Pnpla2
Authors: Kim Kun Ho , Yue Feng , Jia Zhihao , Chen Jingjuan , Qiu Jiamin , Strange Madigan M. , Chen Xiyue , Roseguini Bruno Tesini , Hu Changdeng , Kuang Shihuan
Published: May 2022

Skeletal muscle plays a vital role in regulating systemic energy metabolism. Defects in skeletal muscle energy production exacerbate chronic metabolic disorders. Protein arginine methyltransferase 5 (PRMT5) catalyzes arginine methylation and regulates a plethora of cellular processes in many tissues, but its function in skeletal muscle is poorly defined. Using a skeletal muscle specific Prmt5 knockout mouse model (Prmt5MKO), we observed that Prmt5 KO led to a reduction of myofiber size, compromised contractile function, and exercise performance. In addition, Prmt5KO muscles had fewer oxidative fiber type and correspondingly more glycolytic myofibers. Prmt5MKO mice also exhibit systemic metabolic defects and abnormal lipid droplet biogenesis within skeletal muscle, resulting in reduced fat mass in response to high‐fat‐diet. Mechanistic studies demonstrated that PRMT5 mediates dimethylation of H4R3 in the promoter region of Pnpla2 (encoding ATGL, the rate‐limiting enzyme in lipolysis), and loss of Prmt5 results in elevated level of ATGL. Accordingly, constitutive deletion of Pnpla2in skeletal muscle rescued muscle mass and function of Prmt5MKO mice. Taken together, our findings delineate a novel function of Prmt5 as a regulator of lipid metabolism in myocytes through repressing Pnpla2 expression.
A mast cell stabilizer attenuates pathological angiogenesis in a model of choroidal neovascularization
Authors: Dabouz Rabah , Abram Pénélope , Rivera José Carlos , Lahaie Isabelle , Chemtob Sylvain
Published: May 2022

Age‐related macular degeneration (AMD) is one of the leading causes of irreversible blindness in the elderly worldwide. Wet AMD is characterized by pathologic choroidal neovascularization that invades the RPE and compromises retinal function. Although anti‐vascular endothelial growth factor (anti‐VEGF) therapy has been shown to improve symptoms of wet AMD in a large number of people, long‐term treatment is associated with the development of geographic atrophy. The development of new therapeutic alternatives to prevent the progression of exudative AMD is still necessary. Inflammation and deterioration of the RPE are considered to be the main sources of the pathogenesis of AMD. Recent studies have reported accumulation and degranulation of mast cells in the compromised choroid of patients with AMD. When activated, mast cells can secrete a variety of biologically active mediators, including inflammatory cytokines and proteolytic enzymes such as tryptase. However, the precise role of mast cells in the pathogenesis of AMD remains largely unknown. We are interested in how mast cells participate in the initiation of inflammation in the choroid which results in pathological choroidal neovascularization. We investigated the effect of a mast cell stabilizer on angiogenic response in the choroid. The angiogenic effect of a mast cell stabilizer, ketotifen fumarate, was evaluated in laser‐induced CNV model. Mice received intraperitoneal injections of ketotifen fumarate (5 and 25 mg/kg/d) or vehicle. CNV area and mononuclear phagocytes were determined respectively by using lectin staining and an anti–IBA‐1 antibody on RPE/choroid flat mounts. CNV was attenuated by ketotifen fumarate with no effect on inflammatory cell recruitment. Conditioned media from activated peritoneal mast cells exerted proangiogenic effects on vascular sprouting. Tryptase increased choroidal endothelial cell migration and choroidal vascular sprouting. The study supports possible modulation of mast cells as a therapeutic modality for CNV.
Characterization of the Three Dimensional Genome in Human Skeletal Muscle Progenitor Cells
Authors: Romero Matthew A. , Nicoletti Chiara , Chien Peggie , Saleh Kholoud , Gibbs Devin , Gane Lily , Caputo Luca , Puri Pier L. , Pyle April D.
Published: May 2022

Duchenne Muscular Dystrophy (DMD) is a devastating disease with no cure affecting approximately 1 in 3,500‐5,000 boys. Stem cell treatments using skeletal muscle stem cells (or satellite cells, SCs) provide great potential for regenerating new muscle and we have developed directed differentiation strategies to generate skeletal muscle cells from human induced pluripotent stem cells (hiPSCs). Our work has shown that hiPSCs generate PAX7+ skeletal muscle progenitor cells (SMPCs) resembling early myogenic cells that align closer to week 7‐12 in human development and are not equivalent to adult SCs. We are interested in understanding the key molecular and functional differences that control SMPC versus SC cell states. Recently, there has been an intense interest in the three dimensional (3D) organization of the genome and its involvement in cell specific gene regulation. This has led to the discovery of chromatin loops between gene enhancers and promoters as well as self‐interacting domains termed topologically associating domains (TADs). Recently published data support a role for the 3D genome in cellular differentiation, however, the differences between the 3D genome in human SMPCs compared to adult SCs is unknown. High throughput chromosome conformation capture (Hi‐C) was used to characterize the 3D genome of SMPCs. We found genome‐wide 3D configurations were different between hPSCs and SMPCs as was the number of TADs. Interestingly, TAD size was also different between cell types, suggesting dynamic control of TADs during differentiation. When focusing on the PAX7 locus, TAD boundaries differ between cell types further highlighting the dynamic nature of TADs with respect to cell specific gene expression. Not all muscle specific loci were different between cell types, however, suggesting that some TADs may be pre‐established early in the differentiation process while others are established de‐novo. With respect to chromatin looping at the PAX7 locus, we found SMPC specific looping between the PAX7 promoter and downstream sequences that were unique in SMPCs. Considering that PAX7 enhancer sequences have yet to be determined, these sequences may serve as candidate enhancers for PAX7. These data, for the first time, characterize the 3D genome of human SMPCs using Hi‐C. Moreover, these data provide candidate enhancer sequences for that could provide unique candidates for support of PAX7 SMPCs.
Comparative Growth of the Tympanic Cavity in Primates
Authors: Franklin Katheryn P. , Haynes Laura K. , Smith Timothy D. , DeLeon Valerie B.
Published: May 2022

Primate auditory structures are morphologically indicative of taxonomy and phylogeny. The tympanic cavity houses the three articulating ear ossicles: malleus, incus, and stapes. The ossicles amplify sound waves from mechanical vibrations to the cochlea, a sensory organ, where it can then be interpreted by the organism. All primates are characterized by a petrous bulla, but the extent of the tympanic cavity varies across taxa.

Our sample of newborn and adult individuals representing strepsirrhines (e.g., Galago moholi and Nycticebus pygmaeus) and haplorhines (e.g., Aotus nancymaae and Cebuella pygmaea) allowed us to study the comparative growth of these structures. Using a combination of conventional CT data and diffusion iodine contrast‐enhanced CT (diceCT) data, we created 3D models of auditory structures using 3DSlicer. Metric data included angles between ear ossicles, surface area of the tympanic membrane, surface area of the stapes footplate, and overall tympanic cavity volume. Many differences among major clades are already evident at the newborn stages in this sample. The pneumatization of accessory cavities in newborns has been initiated. For example, in the newborn Galago moholi, pneumatization of accessory cavities is most pronounced posteriorly. In contrast, in the newborn Aotus nancymaae, we see early evidence of the anterior accessory cavity. Mesh‐to‐mesh comparisons of endocasts of the cavity indicate structural changes through ontogeny. Additionally, the surface area of the tympanic membrane remains consistent through growth.

This research allows for a better understanding of the relationship between the functional morphology of the auditory system and audible frequency levels. Haplorhines are adapted to lower frequencies than strepsirrhines. This adaptation is discernable at birth, and key spatial relationships of ossicles are maintained through ontogeny even as spatial configuration of the cranium as a whole undergoes profound change due to pneumatic expansion of sinus cavities and growth of soft tissue structures.
Do Racial Differences Exist in Mechanoreflex Sensitivity in Young Healthy Males?
Authors: Ives Stephen , Giuriato Gaia , Lynch Meahan , Lora Brian , Basso Emma , Tomasi Tawn , Finegan Emma , Schickler Jack , Zaleski Kendall , Gyampo Abena , Venturelli Massimo
Published: May 2022

Cardiovascular morbidity and mortality rates are highest among Black Americans (BA), the mechanisms of which are complex and not completely understood. Altered autonomic reflexes or sympathetic transduction could contribute to elevations in baseline blood pressure or an exaggerated exercise pressor response, thereby increasing CVD risk; though no studies have explored whether mechanoreflex sensitivity, a component of the exercise pressor reflex, is altered in BA. PURPOSE: Using passive leg movement (PLM), as model of activating the mechanoreflex and an assessment of lower limb vascular function, the aim of this study was to compare the central and peripheral hemodynamic responses in young healthy Black (BA) and White American (WA) males. METHODS: Young (21±4 yr) healthy BA (n = 9) and WA (n = 10) males, matched for physical activity, were instrumented to continuously monitor central and peripheral hemodynamics using Finger Photoplethysmography (Finometer) and frequency domain multi‐distance near‐infrared spectroscopy (NIRS) of the vastus lateralis (Oxiplex TS), respectively. After 1 minute of baseline, subjects underwent continuous PLM at 1 hz for two minutes, while tissue oxygen saturation (StO2%), cardiac output (CO), heart rate (HR), stroke volume (SV), and mean arterial pressure (MAP) were continuously recorded. RESULTS: Resting HR (61±3 vs. 62±3 beats/min), SV (89±5 vs. 92±5 mL/beat), CO (5.4±0.4 vs. 4.4±0.5 L/min), and MAP (92±5 vs. 86±3 mmHg) were not different between BA and WA, respectively (all, p>0.05). The individual peak PLM‐induced changes in HR (6±2 vs. 11±3 Δbeats/min, p = 0.06), SV (7.3±1.6 vs. 11.4±1.9 ΔmL/beat, p = 0.04), and CO (0.7±0.2 vs. 1.0±0.2 ΔL/min, p = 0.09) were lower in BA, however the MAP response (5.3±1.4 vs. 6.0±0.8 ΔmmHg, p > 0.05) was not different. The peak PLM‐induced change in StO2 was significantly attenuated in BA (1.6±0.5 vs. 3.8±0.4 Δ%, p=0.01). As a surrogate of nitric oxide, urinary nitrate+nitrate were not different between groups (2.89±1.67 vs. 2.00±1.35 μM, p>0.05). CONCLUSION: A novel insight from the current study reveals that Black American men had an attenuated mechanoreflex response to PLM as compared to White American men. However, Black Americans had a lower peripheral hemodynamic response, perhaps the result of the altered mechanoreflex or suggestive of lower limb vascular dysfunction, which might explain a propensity towards elevated rates of peripheral vascular disease in Black Americans.
Alcohol‐based Hand Sanitizer: Comparing Formulations to Aggressively withstand Bacteria
Authors: Galloway Monea
Published: May 2022

Due to Covid‐19, satisfactory hand washing/hygiene is more vital than ever. And realistically people do not always get up to wash their hand with soap and water every single time. People look for easy access which is hand sanitizer. In this study two formulation of alcohol‐based hand sanitizers both contain 75% Isopropyl Alcohol but formulation #1 has 30% Hydrogen Peroxide. Testing the formulations effectiveness by comparing it to other store brand hand sanitizers (Germ X, Walgreens, Bath and Body Work, Artificial, and Purell). The method used in this experiment placing 100 microliters of bacteria onto Agar plate. Used cotton swab to spread it out and let it dry. Place holes inside of the agar plate and put 200 microliters of hand sanitizer in each hole and let it incubate overnight at 37℃. Next day measure the zone of inhibition in millimeters. In conclusion, this study results show that the more Alcohol is present in the hand sanitizer the less bacteria can grow. The less viscosity the hand sanitizer is the more surface it can cover which means it is able to kill more bacteria with less product. But also found out that Formulation #1 contains Hydrogen Peroxide which gave great result but there is a risk of over kill of bacteria of using this formulation which can potentially not be safe for usage.
Effects of contraction and feeding on skeletal muscle protein synthesis during the initiation of cachexia
Authors: Counts Brittany , Halle Jessica , Carson James
Published: May 2022

Muscle contraction and feeding are potent regulators of skeletal muscle protein synthesis. Cancer cachexia can suppress muscle protein synthesis through Akt/mTORC1 signaling suppression. Cachexia also suppresses acute contraction‐induced muscle protein synthesis. However, the cancer environment’s impact on the combined feeding and contraction activation of protein synthesis during the initiation of cachexia is not well understood. Therefore, we examined the cancer environment’s effect on the muscle protein synthesis response to an acute bout of muscle contraction with and without feeding.

METHODS

Male C57BL/6J (B6; N=36) were injected with 1 x 106 Lewis Lung Carcinoma (LLC) cells or PBS subcutaneously in the right flank and were monitored for up to 30 days. Following an overnight 12hr fast, mice were given ad libitum access to a food pellet for 1hr (fed) or fasted for an additional hour (fast). Subsequently, mice were subjected to low‐frequency electrical stimulation (LFES) for 30 minutes and sacrificed 3hrs post. Puromycin was injected 30min before sacrifice for protein synthesis measurements. Gastrocnemius muscle was examined for protein expression and values normalized to the contralateral limb.

RESULTS

In PBS mice, LFES induced rpS6 (9.5‐fold) and protein synthesis (4.7‐fold). LFES induced rpS6 (1.7‐fold) and protein synthesis (0.9‐fold) in LLC mice. Overall, rpS6 and protein synthesis were lower in the LLC mice compared to PBS. Feeding increased muscle rpS6 and protein synthesis in PBS mice (p<0.001) but not in LLC (p=0.821 and p=0.642) mice. Feeding and LFES synergistically induce rpS6 and protein synthesis in PBS mice; however, this was not present in LLC mice.

CONCLUSION

We report that contraction’s ability to increase muscle protein synthesis is suppressed in mice initiating cachexia. The ability for feeding to increase muscle protein synthesis is also suppressed in mice initiating cachexia. Notably, the combined effects of feeding and contraction were insufficient to synergistically improve muscle protein synthesis as in healthy mice. Future studies should determine why feeding was not sufficient to induce muscle protein synthesis in mice initiating cachexia.
Impact of cell‐free hemoglobin on oxygen pressure dynamics in muscles comprised primarily of fast‐twitch fibers
Authors: Calvo Edward N. , Vera Kaiea , Hashimoto Ann , Ferguson Scott K.
Published: May 2022

Cell free hemoglobin (Hb), released due to hemolysis, reduces the bioavailability of nitric oxide (NO) and the microvascular PO2 (PO2mv, the pressure head that facilitates blood‐myocyte O2 flux) during contractions in mixed fiber‐type skeletal muscle. Despite the known impacts of cell‐free Hb on mixed fiber type muscles, its effect within muscles composed primarily of fast‐twitch fibers remains unknown. Thus, the purpose of this investigation was to test the hypothesis that cell free Hb would lower the PO2mv in the white (fast‐twitch) portion of the gastrocnemius muscle during muscle contractions with no effect at rest or during the rest‐contraction transition. Six young‐adult male Sprague‐Dawley rats had the white portion of the gastrocnemius muscle surgically exposed (100% type IIb + dx). PO2mv was measured at rest and during 180 s of electrically induced contractions (1 Hz, 6‐8 v) under control and following 50 mg of Hb infusion (tail‐artery catheter). Hb resulted in a 48% increase in mean arterial pressure at the onset of muscle contractions (control: 97.16 ± 6.5, Hb 143.40 ± 9.0 mmHg, p<0.01), significantly shortened time‐delay (control 14.3 ± 2.0, Hb 4.8 ± 1.6 s, p<0.02), and mean response time (control 24.9 ± 1.2, Hb 16.4 ± 2.0 s, p<0.02). There were no between‐condition differences in steady‐state (control 10.4 ± 1.4, Hb 14.1 ± 1.4 mmHg, p>0.05) or baseline PO2mv (control 16.4 ± 0.2, Hb 19.1 ± 0.01). Acute exposure to cell‐free Hb resulted in a faster fall in the PO2mv during the rest‐contraction transition. However, despite a significant increase in mean arterial pressure, there were no differences in the PO2mv observed during the contracting steady state. These results suggest that cell free Hb significantly increases vascular resistance within fast‐twitch muscle, which causes O2 delivery‐to‐utilization mismatch at the onset of muscle contractions. These findings provide a potential mechanism by which hemolytic diseases like sickle cell disease impair exercise tolerance. Given that slow‐twitch muscles rely more heavily on NO to support O2 delivery at rest and during contractions, it is likely that the effects observed in the present investigation will be exacerbated in highly oxidative muscles.
Acat‐1 Inhibition Reduces Inflammatory Response to Bleomycin‐mediated Lung Injury
Authors: Stevenson Emily R. , Wilkinson Melissa L. , Abramova Elena , Guo Chiangjiang , Gow Andrew J.
Published: May 2022

Acute lung injury (ALI) is characterized by epithelial damage, barrier dysfunction, and pulmonary edema. Macrophage (MΦ) activation and failure to resolve play a role in in ALI, thus MΦ phenotype modulation is a rational target for therapeutic intervention. Large, lipid‐laden MΦs have been observed in various injury models, including intratracheal bleomycin (ITB), suggesting that lipid storage may play a role in ALI severity. The mitochondrial enzyme Acat‐1 is highly expressed in MΦs where it catalyzes the esterification of cholesterol, leading to intracellular lipid accumulation. We hypothesize that inhibition of Acat‐1 will reduce MΦ activation and reduce ITB‐mediated lung injury. K‐604, a selective inhibitor of Acat‐1, was used to reduce lipid accumulation in ITB. Male and female C57BL6/J mice (n=16‐21/group) were administered PBS, K‐604, ITB, or ITB +K‐604 on d0, PBS or K‐604 on d3, and were sacrificed on d7. ITB caused significant (*p<0.05 v PBS) body weight loss (‐13.92±2.05%* v 2.66±0.78%) and an increase in cholesterol accumulation (71.63±11.7 μM* v 15.51±9.1 μM) and size (29.67±10.6 μm* v 11±4.3 μm) of pulmonary MΦs. These changes were mitigated by Acat‐1 inhibition, as ITB+K‐604 mice had significantly (#p<0.05 v ITB) reduced body weight loss (4.04±1.03%#), cholesterol accumulation (13.79±5.4#), and MΦ diameter (14.0±3.7 μm#), confirming successful inhibition of Acat‐1 in the lung. Histological analysis showed that K‐604 significantly reduced ITB‐induced alveolar wall thickening (2.3±0.05 μm# v 4.35±0.04 μm) and reduced measures of consolidation and cell infiltration. Surface active function was normalized as indicated by a significant decrease in phospholipid:SP‐B ratio in ITB+K‐604 compared to ITB (7.95±1.22# v 13.28±2.17). K‐604 administration rescued ITB‐mediated loss of resident alveolar MΦs (CD45+/Siglec F+/F/480+, CD11c+, CD11b‐) (72.00±5.67%# v 49.58±8.52%) and was found to decrease the % of pro‐inflammatory alveolar MΦs (CD45+/Siglec F+/F/480+, Ly6c+, CD206‐) (3.86±0.88%# v 8.22±1.76%). K‐604 reduced ITB‐mediated increases in NOS2 (64.23±20.07# v 131.89±17.07) and ARG1 expression (42.39±8.14# v 177.41±52.2) in BAL MΦs, suggesting reduced inflammatory signaling and immunometabolic demand. In our ITB model, K‐604 also decreased the % of interstitial MΦs (IMs) (tissue‐derived CD45+, Siglec F ‐, F4/80+, CD11b+) expressing markers of maturity and fibrotic potential (CD11c+/CD206+) (5.89±2.15%# v 19.72±1.93%). IMs were also found to have an increased rate of lipid uptake after K‐604 regardless of ITB administration as measured by the uptake of fluorescently labeled LDL and visualization by confocal microscopy. These data, along with changes in cholesterol ester accumulation, suggest that Acat‐1 inhibition alters lipid storage and uptake within pulmonary macrophages, affecting cell phenotype and function. Thus, Acat‐1 may be a target for intervention in ALI.
Regulation of the Nuclear Bile Acid Receptor, Farnesoid X Receptor, by the Omega‐3 Polyunsaturated Fatty Acid, Alpha‐Linolenic Acid, in Colonic Epithelial Cells
Authors: Smyth Jessica S. , Fallon Ciara M. , Keely Stephen J.
Published: May 2022

Introduction and Aims

The intestinal epithelium forms the interface between the body and the luminal contents, facilitating fluid and electrolyte transport, while also acting as a barrier to harmful pathogens. Dysregulation of barrier and transport function is associated with the pathogenesis of a number of conditions, including chronic diarrhoeal and inflammatory bowel diseases (IBD). Previous studies from ours, and other laboratories, have identified the nuclear bile acid receptor, farnesoid x receptor (FXR), as an excellent target for the development of new anti‐diarrhoeal and anti‐inflammatory therapeutics. Polyunsaturated fatty acids (PUFAs), such as alpha‐linolenic acid (ALA), are a group of bioactive phytochemicals, which have been shown in other systems to modulate FXR activity. PUFAs are also thought to be ligands for another group of nuclear receptors, known as the peroxisome proliferator‐activated receptors (PPARs), which have been recently shown to modulate FXR expression. Here, we set out to investigate a possible role for ALA in regulating farnesoid x receptor signalling in colonic epithelial cells.

Methods

T84 human colonic epithelial cells were cultured as polarised monolayers on permeable supports and treated bilaterally with alpha‐linolenic acid (ALA) (100 µM) for 1 – 24 hours, in the presence or absence of the FXR agonist, GW4064 (5 µM), or the PPARg antagonist, GW9662 (20 µM). Levels of FXR, FGF19, an index of FXR activation, and ANGPTL4, a PPAR target gene, were measured by qRT‐PCR, western blotting, or ELISA.

Results

Treatment of T84 cells with ALA increased FXR expression in a time dependent fashion. Maximal effects of ALA occurred after 6 hrs when increases in FXR mRNA and protein were 8.65 ± 0.80 fold (n = 4; p < 0.01) and 4.44 ± 0.85 fold (n = 4) of untreated controls, respectively. Moreover, treatment of the cells with ALA potentiated GW4064‐induced expression of the FXR target gene, FGF‐19, at both mRNA and protein levels by 2.66 ± 0.56 (n = 4) and 5.52 ± 1.52 (n = 6), respectively. The effects of ALA on FXR expression and activity were mimicked by the PPARg agonist, rosiglitazone (1 mM). Treatment with ALA also significantly increased mRNA expression of the PPAR target gene, ANGPTL4, by 56.69 ± 5.7 (n = 4; p < 0.01), while the PPARg antagonist, GW9662 (20 µM; 1 hr), inhibited ALA‐induced FXR mRNA expression by 0.44 ± 0.12 fold (n =4) and protein by 0.23 ± 0.06 fold (n = 3).

Conclusion

The dietary PUFA, ALA, regulates colonic epithelial FXR expression through mechanisms that involve activation of PPARγ. By virtue of their ability to upregulate FXR expression and activity, PUFAs, such as ALA, have excellent potential for development as FXR‐targeted nutraceuticals for the treatment and prevention of intestinal disease.
Immunoelectron Microscopy of Trace Amine‐Associate Receptor 1 Intracellular Localization
Authors: Huey Julia , Shi Xiao , Janowsky Aaron
Published: May 2022

Trace amine‐associated receptor 1 (TAAR1) is a G protein‐coupled receptor (GPCR) in brain regions that are critical to reward and habit formation. TAAR1 is activated by a variety of substituted phenethylamines (e.g. methamphetamine, MA), and is uniquely involved in the mechanism of action of amphetamine‐like psychostimulants. Pharmacological manipulation of TAAR1 alters the spontaneous firing rate of neurons in the ventral tegmental area, and psychiatric disorders characterized by dysregulated dopaminergic neurotransmission, including schizophrenia and substance use disorders, have been associated with altered trace amine levels or TAAR1 polymorphisms.

Unlike many GPCRs, TAAR1 is an intracellular receptor; rather than localizing to the plasma membrane, TAAR1 is associated with unidentified membranous compartments within the cell. Previous efforts to identify the intracellular localization of TAAR1 have had limited success due to difficulty with heterologous expression systems and a lack of sufficiently specific antibodies, as well as inherent spatial resolution limits of light‐based microscopic techniques. In order to determine the precise subcellular localization of TAAR1, immunoelectron microscopy was performed in HEK293T cells stably expressing human TAAR1 with a C‐terminal EGFP tag. Preliminary results suggest that TAAR1 localizes to the endoplasmic reticulum and mitochondria. Future experiments using similar techniques will explore TAAR1 localization in primary neurons. Together, these results will further elucidate the molecular mechanisms by which TAAR1 signals within neurons and ultimately alters neurotransmission.
Role of the High‐Conductance Calcium‐Activated Potassium Chanel in first order mesenteric artery of hypercaloric diet rat model
Authors: Hernandez‐Garcia Ana P.
Published: May 2022

Obesity has been identified like as a risk factor of metabolic syndrome. The High‐Conductance Calcium‐Activated Potassium Channel (BKCa) in vascular smooth muscle cells regulates membrane potential and control myogenic tone.

Objective

evaluated the role of the BKCa channel in first order mesenteric arteries of rats feed with a hypercaloric diet for 18 and 28 weeks.

Methodology

We performed isometric tension experiments in first and second order mesenteric arteries rings and Patch Clamp recordings of vascular smooth muscle cells isolated of the same vascular bed.

Results

The rats feed with a hypercaloric diet for 18 weeks shows an augmented un percentage of adipose tissue, triglycerides, glucose tolerance curve, blood pressure and more relaxation to BKCa channel activator NS11021 un rings precontracted with phenylephrine. At 28 weeks of evolution, an increase in percentage of adipose tissue with respect to body weight was observed, as well as an increase in blood pressure, Regarding BKCa channel function, an increase in current density was observed in the experimental group with respect to the control group.

Conclusion

Changes have been developed at the metabolic level in the groups of the hypercaloric diet, with changes in the BKCa channels, a gain of function in first order mesenteric rings of the 18 weeks group and in cells isolated from these arteries at 28 weeks group. Nevertheless, at 28 weeks of evolution, first order mesenteric artery rings no longer showed the gain in function observed in the previous group, which suggest a compensatory mechanism maybe associated to aging.
Breathing rhythm stability is higher after intravenous injection of codeine relative to fentanyl in cats
Authors: Shen Tabitha Y. , Olsen Wendy L. , Rose Melanie J. , Wang Wei , Bolser Donald C.
Published: May 2022

Codeine is one of the opioids of abuse that is available by prescription, and fentanyl is the leading opioid drug of abuse. Both codeine and fentanyl are µ‐opioid agonists that are strong respiratory depressants. However, unlike fentanyl, codeine also binds to nicotinic receptors. We hypothesized that influence of these drugs on the stability of breathing would differ due to the relative non‐specificity of codeine. Ten anesthetized, spontaneously breathing adult cats were tracheotomized, and EMG activity was recorded from inspiratory muscles. Dose responses to codeine (n=5, 0.1 – 10 mg/kg, i.v.) or fentanyl (n=5, 0.1 – 10 ng/kg, i.v.) were performed in separate groups of animals. Total breathing cycle time (Ttot) was measured for 30 breaths at each dose. Measurements of Ttot were taken more than 5 minutes following administration of the drugs. Poincaré plots were constructed for Ttot, where an ellipse was fit to the data (Ɵ=45°). The ratio (SD1/SD2) was computed at each dose, where SD1 was the length the ellipse perpendicular to the line of identity, and SD2 was the length along the line of identity. SD1 is associated with short‐term variability and SD2 with long‐term variability of the data. The dose response relationships showed similar increases in Ttot from vehicle to the highest dose between codeine and fentanyl (codeine: 2.4 ± 0.2 s to 4.4 ± 1.0 s; fentanyl: 2.5 ± 0.4 s to 5.4 ± 0.5 s). Transient apnea (< 60 s) was commonly observed immediately following doses of codeine that were larger than 1 mg/kg, but was not observed after any dose of fentanyl. SD1/SD2 differed between the two drugs, where SD1/SD2 did not change across doses for codeine, and SD1/SD2 decreased significantly in a dose‐dependent manner from 0.3 ng/kg (0.77 ± 0.10) to the 3 ng/kg dose (0.32 ± 0.7) for fentanyl. The shift in the SD1/SD2 ratio after fentanyl was driven more by changes in SD2 (81% compared to vehicle) rather than SD1 (‐17% compared to vehicle). We conclude that codeine induces relatively similar changes of short and long‐term variability of Ttot, whereas fentanyl preferentially reduces long‐term variability of Ttot. Alterations in long‐term variability are more consistent with a potential for network reconfiguration rather than the respiratory network correcting for breath‐to‐breath requirements. Our data suggest that a Poincaré plot may be a sensitive metric of the disruption of respiratory control dynamics for the µ‐receptor selective fentanyl relative to the µ‐opioid agonist/nicotinic ligand codeine.