bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypertensive Dahl salt‐sensitive rats produce a blunted diuresis to central N/OFQ which is restored by CNS G‐alpha q protein knockdown
Authors: Wainford Richard David , Kapusta Daniel R 
Published: June 2021

Hypertensive Dahl salt‐sensitive (DSS) rats on high NaCl intake have enhanced plasma vasopressin (AVP). We examined whether DSS rats can effectively excrete water following intracerebroventricular (i.c.v.) injection of nociceptin/orphanin FQ (N/OFQ), a peptide that evokes profound diuresis via inhibition of AVP release.Methods Changes in CV and renal excretory function produced by i.c.v. N/OFQ (5.5 nmol) were examined in conscious chronically instrumented DSS rats maintained (3 weeks) on 8% NaCl (N=6) or normal chow (N=6). Separate animals fed 8% NaCl diet (N=6), were pretreated with a Gαq oligodeoxynucleotide (ODN) (25 μg), which we have shown participates in the recovery (AVP stimulatory) phase following the peak diuresis to N/OFQ. MAP and HR were recorded and urine collected during control and for 80‐min (10‐min periods) following i.c.v. N/OFQ.Results Dahl SS rats fed an 8% NaCl diet became hypertensive (normal chow, MAP 128 ± 4 mmHg; 8% NaCl chow, 169 ± 7 mmHg, P< 0.05). The diuresis to i.c.v. N/OFQ was blunted in duration and magnitude in hypertensive DSS rats (peak diuresis; normotensive DSS 50‐min, 174 ± 18 μl/min; hypertensive DSS 30‐min, 110 ± 17 μl/min, P< 0.05). In hypertensive DSS rats, i.c.v. Gαq pre‐treatment fully restored the diuresis to i.c.v. N/OFQ (peak; DSS + Gαq ODN 50‐min, 170 ± 14 μl/min P< 0.05).Conclusion Hypertensive DSS rats produced a blunted diuresis to i.c.v. N/OFQ, which was restored to a normal diuretic pattern by prior central Gαq protein knockdown. Thus, in DSS rats, high NaCl may enhance central Gαq protein expression and attenuate the inhibitory effects of this, and possibly other Gαq‐protein coupled receptor ligands on AVP secretion. DK43337, HL 071212, P20 RR018766
Mitochondrial function in physically active older adults with sarcopenia
Authors: Waters Debra L , Qualls Clifford , Gasparovich Charles , Mullins Paul , Raj Dominic 
Published: June 2021

Sarcopenia is prevalent during aging and has been linked to mitochondrial dysfunction. The role of physical activity in protecting against sarcopenia and preserving mitochondrial function is debated due to its dual role of increasing muscle function while increasing free radical production. To investigate these relationships, healthy normal lean (NL: n=15) and sarcopenic (SS: n=9) subjects were recruited based on body composition (DXA, Lunar DPXTM), age (78.5 ± 5 yr), sex, and self‐reported long‐term physical activity. Calf mitochondrial function was assessed using 4 T 31PMRS (Bruker Biospin). Resistance was 50% of 1MVC and total work measured by force transducer. Total work was lower in SS (p<0.001) and data were scaled to total work output. At rest [Pi] was modestly elevated in SS (p=0.02). End of exercise [Pi] was lower (p=0.007) and [ADP] and pH higher (p=0.0002, p=0.05 respectively) in the SS. The [PCr] recovery rates were not different between the groups, but [ADP] during recovery remained elevated in SS (p=0.02). Elevated [ADP] during exercise can imply impaired mitochondrial function. However, the similar [PCr] recovery rates suggest an increased proton efflux in SS, that would increase pH and raise [ADP] via increased mitochondrial respiration. Our data indicate that a relationship exists between sarcopenia, long‐term physical activity, and mitochondrial function that remains to be fully elucidated.Supported by NIH/NIA R21 AG21560‐01, NCRR MO1‐RR‐00997
Neuropeptide‐Y and prepro‐orexin gene expression increases after continuous sleep deprivation but not sleep restriction in rats
Authors: D′Almeida Vânia , Forcina Martins Paulo J. , Tufik Sérgio 
Published: June 2021

The sleep loss is characterized by increased food intake in human and rats. However, the statement that in rats the sleep deprivation‐induced hyperphagia is followed by weight loss, suggests that the physiological factors involved are different from those proposed to human. Our objective was to investigate the sleep deprivation‐induced changes on feeding behavior and body weight by the platform technique in rats and to access the repercussions on hypothalamic expression of neuropeptides related to sleep and food intake control. Rats receiving a liquid diet were sleep deprived by the platform technique for 24, 48, 72, 96 hours and for 21 days by sleep restriction. We investigated feed behavior, body weight, and hypothalamic prepro‐orexin, neuropeptide Y, insulin receptor, agouti related peptide and POMC expression. Increased gene expression of the prepro‐orexin was closer related to sleep debit than food intake changes. Despite of unchanged body weight, rats continuously sleep deprived, but not the restricted ones, showed increases in prepro‐orexin and neuropeptide Y gene expression which can interacts to food intake augmentation during sleep deprivation.Financial support: FAPESP, CNPq and AFIP.
Altered IP3 receptors, IP3‐dependent Ca2+ transients and Ca2+‐dependent gene expression in a Duchenne muscular dystrophy cell line
Authors: Jaimovich Enrique , Juretic Nevenka , García Isaac , Hartley Ricardo , Liberona Jose Luis , Figueroa Reinaldo , Riveros Nora , Molgó Jordi , Cárdenas Julio Cesar 
Published: June 2021

Although deregulation of calcium handling has been recognized to play a role in Duchenne muscular dystrophy (DMD), little is known about the role of calcium release in this phenomenon. Inositol 1,4,5 trisphosphate receptors (IP3Rs) are located in the sarcoplasmic reticulum and nucleus of skeletal muscle cells. Upon electrical stimulation (400pulses, 1ms, 45Hz), these receptors mediate slow calcium transients, involved in gene regulation. Using normal (RCMH) and dystrophic (RCDMD) human skeletal muscle cell lines, we explored the distribution of IP3Rs as well as IP3‐dependent calcium dynamics. Mouse oligonucleotide microarrays alowed analysis of total RNA from RCMH and RCDM myotubes obtained 4h post‐stimulus.Dystrophic cells show a five‐fold over expression of type‐2 IP3R; type‐2 IP3R locates in the nucleus in RCDMD cells, while type‐1 and type‐3 IP3Rs appear also to locate differently. Both cell lines displayed a slow calcium transient upon electrical stimulation, the signal being much faster and larger in RCDMD cells. IP3‐mediated calcium signals induced phosphorylation of extra cellular signal‐regulated kinase (ERK1/2) in normal but not in dystrophic cells. Statistical analysis of microarrays resulted in 132 and 150 differentially expressed genes in RCMH and RCDMD respectively. As IP3‐dependent calcium signals appear to be the first step in regulation of gene expression, impairment of this pathway could play an important role in DMD patho‐physiology.FONDAP 15010006
Inositol hexaphosphate alters mucin expression in the intestinal mucosa of mice
Authors: Onyango Edward , Madsen Cathy , Gendler Sandra 
Published: June 2021

Inositol hexaphosphate (IP6 or phytic acid) is thought to be the active ingredient in legumes and cereals that provides anti‐cancer activity. Our goal is to understand the influence of IP6 on mucin expression (Muc1 and Muc2, specifically) in the mouse intestine. C57BL/6 mice were randomized into 3 groups of 6 mice. Mice were orally dosed with IP6 (0, 1, 2 g/kg BW) for 5 days and sacrificed on the sixth day. Sections of the small intestine were removed, fixed in methacarn, sectioned and stained with Alcian blue‐PAS to visualize mucins. Mucosa from the jejunum and colon were removed and total RNA prepared using Trizol®. cDNA was prepared using random hexamers and TaqMan minor groove binding probes were used for real time PCR amplification of message for Muc1 and Muc2. Expression of Muc1 in the jejunum was minimal whereas that of Muc2 increased 1.4‐fold at the higher IP6 dose rate. In the colon, expression of both Muc1 and Muc2 increased in mice dosed with IP6. Expression of Muc1 increased 1.6‐fold and 3.8‐fold in mice dosed with 1 and 2 g/kg IP6, respectively. Expression of Muc2 increased 2.0‐fold and 1.7‐fold in mice dosed with 1 and 2 g/kg IP6, respectively. Alcian blue‐PAS stained sections of the colon showed an increase in mucus. Thus, IP6 seems to increase the expression of Muc1 and Muc2 in the mucosa lining of the small intestine, particularly in the colon.Research was supported by East Tennessee State University and Mayo Clinic.
Regulation of activity dependent transmitter release from chromaffin cells by F‐actin and non‐muscle myosin II
Authors: Doreian Bryan William , Fulop Tiberiu , Smith Corey 
Published: June 2021

Adrenal chromaffin cells release catecholamines and neuropeptides upon stimulation. Both transmitter classes are packaged in the same secretory organelle. At basal firing rates, highly soluble catecholamines are released from chromaffin cells by ‘kiss and run’ fusion events. Under acute stress, elevated firing leads to full granule collapse releasing both catecholamine as well as a neuropeptide‐containing proteinacious granule core. Thus, activity dependent transmitter release is regulated by a transition in secretion mode. Here we employ electrochemical, electrophysiological and fluorescence based approaches to investigate the role of actin and myosin in regulating this transition. We show that under basal firing rates, F‐actin networks are maintained stabilizing ‘kiss and run’ fusion events. Under the same stimulation conditions, disruption of F‐actin resulted in conversion to full‐collapse exocytosis. Also, under increased cell stimulation, activation of myosin II and disruption of F‐actin is necessary to drive the full collapse of the granule. Under the same conditions stabilization of F‐actin and inhibition of myosin II resulted in a conversion to ‘kiss and run’ exocytosis. Our results demonstrate that the transition from ‘kiss and run’ to ‘full collapse’ exocytosis depends upon both F‐actin and myosin II, helping to provide essential regulation of the fusion mode and a proper stress response.This work was supported by a grant from the National Institutes of Health (NIH) 5/T/32/HL07887
Alteration of Currents of Large Conductance Calcium‐Activated Potassium Channels by Hyperkalemia in Porcine Arterial Smooth Muscle Cells
Authors: Han Jian‐Guo , Yang Qin , Shen Bing , Yao Xiao‐Qiang , He Guo‐Wei 
Published: June 2021

The wide use of hyperkelemic solutions in cardiac surgery including heart transplantation draws our attention on the effect of hyperkalemia on large conductance calcium‐activated potassium channels (BKCa). The BKCa of arterial smooth muscle cells (SMCs) is pivotal in the regulation of vascular tone. SMCs were enzymatically isolated from porcine coronary arteries. Primary cultures of the SMCs (usually 5–7 days) were used for patch‐clamp study. The effect of K+ with different concentrations (5.4, 20, 60, or 120 mM) was investigated on whole‐cell BKCa current with a holding potential of −60 mV (n=5 for each concentration). The rise of extracellular K+ in bath solutions significantly resulted in increase of BKCa currents in a K+‐concentration dependent manner in comparison with the control solution (5.4mM: 31.6±3.4pA/pF; 20mM: 73.6±11.4pA/pF; 60mM: 108.6±20.6pA/pF; 120mM: 135.2±20.5 pA/pF, p<0.05 one‐way ANOVA). Raise of extracellular K+ concentration increases BKCa activity of the porcine coronary arterial SMCs in a dose‐dependent manner. This may be an important part of the effect of hyperkalemic cardioplegia on the coronary circulation and therefore may have clinical implications in the heart preservation.Acknowledgments: Supported by Hong Kong RGC grant (CUHK4383/03M) and CUHK direct grants (4450171, 4450231, 2041305)
Developing an MRI based method for analyzing differences in blood vessel diameter and brain tissue perfusion in hypertension
Authors: Gillies Robert Milne , Germain Sean , Raizada Mohan , Paton Julian , Walter Glenn 
Published: June 2021

We aimed to develop an MRI based protocol to investigate anatomical differences in brainstem blood vessels between spontaneously hypertensive rats (SHR; n=4) and their normotensive progenitor strain Wistar Kyoto (WKY; n=4) rats. These were compared using high‐resolution multislice, 2D time of flight (TOF) Magnetic Resonance Angiography using different gadolinium (Gd) based contrast agents (Gd‐Albumin, Gadodiamide) to image cerebral blood vessels at 4.7T (TR/TE=18ms/4.3ms, matrix=512x320,nslices=80; nex=4, flip=35°, resolution=68x67x500μm3). Tissue perfusion was measured using dynamic contrast enhancement (TR/TE=12ms/2.8ms, matrix=256x128, nslices=1; nex=1, ΔT=1.5s, images=300, flip=15°, resolution=0.137x0.230x1mm3) or by determining changes in tissue transverse relaxation time pre‐ and post‐contrast enhancement. Images were processed and 3D rendered using Osirix (Mac OS10.4 compatible version). We propose that our protocol will allow measurement and comparison of both blood vessel diameters and tissue perfusion in central cardioregulatory regions in the respective rat strains.Supported by NIH grants HL33610 and 76312.
Fasting affects thermoregulation in the cold, depending on time of the day
Authors: Tokizawa Ken , Uchida Yuki , Nagashima Kei 
Published: June 2021

BACKGROUND:We have shown that circadian rhythm of body temperature (Tb) is finely regulated. However, feeding condition is a factor affecting largely the Tb rhythm. During fasting, Tb gradually decreases in the light (inactive) phase, whereas Tb in the dark (active) phase is maintained at the free‐feeding level. The purpose of the present study was to clarify the mechanism involved in the altered Tb rhythm during fasting.METHODS:Male ICR mice (2–3 mo old), used for the present study, were housed at an ambient temperature (Ta) of 27ºC in a 12:12‐h light‐dark cycle. After 48‐h fasting, Ta was decreased to 20ºC at ZT1‐4 (early light phase) or ZT13‐16 (early dark phase). Tb (biotelemetry) and oxygen consumption (VO2, indirect calorimetry) were measured.RESULTS:During a cold exposure with fasting, Tb decreased by 5.5 ± 2.0ºC at ZT1‐4, and VO2 remained unchanged. However, Tb decreased by only 2.0 ± 0.5ºC at ZT13‐16, which was greater than that in the light phase (p<0.05), and VO2 increased (p<0.05).CONCLUSION:These results indicate that fasting attenuates thermoregulatory response to the cold, and the response differs among time of the day. Factors of feeding condition and time would have influences on the mechanism regulating the Tb rhythm. The possible reason will be presented, based on histological study using c‐Fos immunostaining and molecular analysis of UCP1 mRNA expression in the brown adipose tissue.
Role of hypoxia in muscle function and muscular dystrophy
Authors: Mosqueira Matias M , Baby Santosh M , Budak Murat , Bogdanovich Sasha , Willmann Gabriel , Lahiri Sukhhamay , Khurana Tejvir 
Published: June 2021

Respiratory insufficiency contributes significantly to the morbidity and, is the commonest cause of mortality, in Duchene's muscular dystrophy (DMD). However, surprisingly little is known mechanistically about 1, basic respiratory physiology in the mdx (DMD‐mouse model) &, 2, effects of hypoxia (high altitude) on muscle function.To rigorously evaluate mdx respiration, we custom‐built a plethysmograph (with 1 microlitre sensitivity) and exposed awake adult mdx and control mice to graded levels of hypoxia and hypercapnia to determine respiratory rate (RR), tidal volume (VT), and minute ventilation (VE), HVR and HCVR. Additionally, phrenic nerve discharges were recorded from anesthetized mice to understand the integrated ventilatory response of central and peripheral chemoreceptors. Significant abnormalities were found in mdx mice respiratory parameters during normoxia as well as a blunting of the HVR reflex. Finally, we found anatomical, physiological and transcriptome‐level changes in muscle of animals exposed to hypoxia and high altitude (Mt. Marmolejo & Mt. McKinley). These observations support our hypotheses that dystrophic mice have respiratory abnormalities and that hypoxia itself may contribute as a ‘second‐hit’ to muscle patho‐physiology in DMD.
Preservation of endothelial cell/pericyte adhesion by cilostazol in ischemic limb of diabetic mouse
Authors: Suzuki Tomoharu , Matsushita Shonosuke , Sugimori Haruhiko , Sato Fujio , Sakakibara Yuzuru 
Published: June 2021

Purpose: Degeneration of pericytes and acellular capillaries are increased in the feet of human diabetic patients. Selective loss of adhesion of pericyte to endothelial cell is known to early event in diabetic microangiopathy. In diabetes, inflammation due to endothelial dysfunction is augmented. Cilostazol, a PDE III inhibitor, is reported to reduce inflammation and oxidative stress in diabetic patients. Based on these findings, we investigated the effect of cilostazol on endothelial/pericyte adhesion in ischemic hindlimb of diabetic mice.Method: Type I diabetes was induced by intraperitoneal administration of streptozocin (50mg/kg) for five days in both cilostazol‐fed mice and control‐diet‐fed mice. Resection of femoral artery was conducted to develop hindlimb ischemia. Ten days after the procedure, gastrocnemius muscles were resected. Adhesion of pericyte to endothelial cell was assessed by transmission electron microscopy.Result: The rate of detachment between endothelial cell and pericyte in cilostazol‐fed mice was 1/15, whereas it was 9/8 in non‐cilostazol‐fed mice (p<0.005).Conclusion: Cilostazol preserved endothelial cell/pericyte adhesion in ischemic limb of diabetic mouse. Cilostazol may provide improvement of capillary morphology in diabetic foot in addition to vasodilation.
Quantitative proteomic analysis of distinct mitochondrial subpopulations in diabetic myocardium
Authors: Dabkowski Erinne R , Williamson Courtney L , Hollander John M 
Published: June 2021

Reactive oxygen species resulting from diabetes mellitus contribute to damage and loss of mitochondrial proteins. Two spatially distinct mitochondria populations exist in the cardiac myocyte, interfibrillar mitochondria (IFM), which situate between the myofibrils, and subsarcolemmal mitochondria (SSM), which exist beneath the sarcolemma. The goal of this study was to determine the impact of diabetic insult on proteomic profiles of distinct mitochondrial populations. Swiss Webster mice were made diabetic by streptozotocin injection and sacrificed following diabetes onset. Using 2D‐differential gel electrophoresis and iTRAQTM technology, we determined that proteomic profiles of IFM were affected to a greater extent than SSM, as a result of diabetes. Specific alterations included decreases in ATP synthesizing proteins (ATP synthase, P<0.05) and electron transport chain proteins (cytochrome C oxidase, P<0.05; flavoprotein ubiquinone oxidoreductase, P<0.001). Further, aconitase, a protein prone to oxidation, was decreased in diabetic IFM (P<0.002), while adenine nucleotide translocase, a protein associated with enhanced permeability transition pore opening, was elevated in diabetic IFM (P<0.05). Our results suggest that the IFM are at greater risk for protein loss as a result of diabetes mellitus, which may contribute to the pathogenesis of diabetic cardiomyopathy.(Supported by AHA 0665237B)
Effects of short‐term exercise combined with either high or low glycemic diets on skeletal muscle lipid content in older, insulin resistant adults
Authors: Haus Jacob M , Covey Kelly K , Jessberger John A , Brooks Latina M , Kashyap Sangeeta R , Dasarathy Sri , Flask Chris A , Kirwan John P 
Published: June 2021

We sought to determine whether the reversal of insulin resistance by short‐term exercise combined with different dietary interventions was mediated by changes in IMCL. We hypothesized that 7 consecutive days of exercise plus a low‐glycemic (LG) diet would lead to greater improvements in insulin sensitivity and IMCL than exercise plus a high‐glycemic (HG) diet. Preliminary data are available for 8 men and women (68±1 yr; 32±1 kg/m2) with impaired glucose tolerance. Insulin resistance was determined using the euglycemic‐hyperinsulemic clamp, and IMCL content was measured by localized magnetic resonance spectroscopy of the soleus muscle. Subjects exercised for 60 min/d at an intensity of ~70% VO2max and were provided eucaloric diets (N=4, HG; N=4, LG). The program did not alter VO2max or body weight. Insulin sensitivity (mg/kg/min) increased (P=0.006) in both groups (HG: Pre 3.0±0.5, Post 3.9±0.5; LG: Pre 2.4±0.1, Post 3.9±0.4) and IMCL content (% change) was significantly different between the HG and LG groups (HG: +49%; LG: −40%, P=0.0004). These data indicate that insulin sensitivity improves with short‐term exercise independent of diet or change in IMCL content. The paradox in IMCL content seen with the diet groups may be reflective of alterations in fuel substrate utilization and storage.Supported by NIH Grants T32 HL007887 (JMH), AG12834 (JPK) and RR018390
AAV Delivery of gp91‐shRNA Stimulates Synthesis and Release of Insulin and Attenuates Blood Glucose Level in Type 2 Diabetes
Authors: Wang Xianfu , Wang Xiuqing , Sun Zhongjie 
Published: June 2021

Hypothesis. RNAi inhibition of gp91 improves insulin resistance and decreases blood glucose level.Methods and Results. Doubled stranded shRNA for gp91phox was synthesized and packaged into the AAV to generate AAV.gp91‐shRNA. Two groups of db/bb mice and 2 groups of lean mice were used. One group of db/db mice and 1 group of lean mice received IV injection of AAV.gp91‐shRNA (1×1011 particles) while the other 2 groups received the same doses of AAV.Control‐shRNA served as controls. Blood glucose levels were elevated in db/db mice treated with AAV.Control‐shRNA. AAV.gp91‐shRNA significantly decreased blood glucose level. Contradictory to our hypothesis, AAV.gp91‐shRNA failed to improve insulin resistance in db/db mice. Interestingly, AAV.gp91‐shRNA increased plasma insulin level significantly (by 2 folds). Immunohistochemical (IHC) data showed that RNAi inhibition of gp91phox significantly increased insulin staining in islet cells, indicating increased insulin synthesis. These data suggest that RNAi inhibition of gp91phox decreased blood glucose level by increasing insulin release.Conclusions. AAV delivery of gp91‐shRNA may serve as new approach for improving blood glucose level in type 2 diabetes. NADPH oxidase is not involved in insulin resistance in type 2 diabetes.
Differential host response to Methicillin‐resistant Staphylococcus aureus and Pseudomonas aeruginosa
Authors: Enkhbaatar Perenlei , Jonkam Collette , Traber Lillian , Connelly Rhykka , Lange Matthias , Hamahata Atsumori , Herndon David , Traber Daniel 
Published: June 2021

Despite the outstanding achievement in treatment of sepsis, the mortality rate of septic patients is high. The objective of the study was to describe differential host response to different infectious agents using our well‐established ovine sepsis model.MethodSheep were given the injury via tracheostomy under anesthesia. Study groups: 1) sham, (no injury), n=6; 2) Smoke (Smoke inhalation) n=6; 3) PS (smoke inhalation & Ps. aeruginosa (1011CFU) instilled into the lungs, n=6; 4) MRSA (smoke inhalation & MRSA (1011CFU) instilled into the lungs, n=6. After injury, sheep were awakened, maintained on mechanical ventilation, and fluid resuscitated for 24 h.Results:Mean arterial pressure was similarly depleted in MRSA and PS groups. The severity of lung injury was more pronounced in PS group, which was associated with higher expression of lung IL‐1, 6, and 8. MRSA group had 2‐fold higher fluid retention associated with significantly higher nitric oxide (NO) production and vascular endothelial growth factor (VEGF). The lung tissue arginase level and IL‐13 was higher in PS group.Conclusion:Excess IL‐13 leading to higher arginase activity in PS may result in lesser production of NO. The severe vascular leak in MRSA group may be due to excess NO and VEGF. Differential responses to different pathogenic agents require more focused treatment approach considering the nature of infectious agents and specific host response to it