Heat acclimation induces changes in cardiac mechanical performance: the role of thyroid hormone

1999 ◽  
Vol 276 (2) ◽  
pp. R550-R558 ◽  
Author(s):  
Eynan Mirit ◽  
Aharon Palmon ◽  
Yonathan Hasin ◽  
Michal Horowitz
Keyword(s):  
Drinking Water ◽  
Mechanical Performance ◽  
Systolic Pressure ◽  
Heat Acclimation ◽  
Rt Pcr ◽  
Thyroxine Level ◽  
Rat Hearts ◽  
Langendorff Perfusion ◽  
Steady State Levels

The involvement of reduced thyroxine level in the emergence of heat acclimation-induced negative lusitropic effect was examined. Experiments were carried out on 1) control rat hearts maintained at 24 ± 1°C (C); 2) rat hearts acclimated at 34°C for 1 mo (AC); 3) AC-euthyroid rat hearts, via administration of thyroxine in the drinking water (AT); and 4) hypothyroid rat hearts, maintained at 24 ± 1°C, via administration of thiouracil in the drinking water (CP). Systolic pressure and velocities of contraction (dP/d t ⋅ P) and relaxation (−dP/d t ⋅ P) were measured using the Langendorff perfusion system. The steady-state levels of Ca2+-ATPase and phospholamban mRNAs and the expression of the encoded proteins Ca2+-ATPase (SERCA) and phospholamban (PLB) were measured, using semi-quantitative RT-PCR and Western immunoblotting, respectively. Rat thyroxine levels were measured using RIA. Heat acclimation, which brought about a reduced thyroxine level, led to downregulation of Ca2+-ATPase mRNA expression and translation and upregulation of phospholamban mRNA and PLB. Consequently, the PLB-to-SERCA ratio (PLB/SERCA) of the AC hearts showed a significant increase. These changes, as well as the greater pressure generation and the reduced dP/d t ⋅ P and −dP/d t ⋅ P observed in AC hearts were blunted in the AT hearts. Our data suggest that sustained heat acclimation-induced low thyroxine level has a decisive effect on the contractile machinery of the AC heart. Elevated PLB/SERCA apparently explains the negative lusitropic effect observed in these hearts.

HIF-1α-targeted pathways are activated by heat acclimation and contribute to acclimation-ischemic cross-tolerance in the heart

2005 ◽  
Vol 23 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Alina Maloyan ◽  
Luba Eli-Berchoer ◽  
Gregg L. Semenza ◽  
Gary Gerstenblith ◽  
Michael D. Stern ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Heat Acclimation ◽  
Heme Oxygenase 1 ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Cross Tolerance ◽  
Protein Levels ◽  
Rat Hearts

Hypoxia-inducible factor-1 (HIF-1) is a key regulator of the cellular hypoxic response. We previously showed that HIF-1 activation is essential for heat acclimation (AC) in Caenorhabditis elegans. Metabolic changes in AC rat hearts indicate HIF-1α activation in mammals as well. Here we characterize the HIF-1α profile and the transcriptional activation of its target genes following AC and following heat stress (HS) in hearts from nonacclimated (C; 24°C) and AC (34°C, 1 mo) rats. We used Western blot and immunohistochemistry to measure HIF-1α levels and EMSA and RT-PCR/quantitative RT-PCR to detect expression of the HIF-1α-targeted genes, including vascular endothelial growth factor ( Vegf), heme oxygenase-1 ( HO1), erythropoietin ( Epo), and Epo receptor ( EpoR). EpoR and Epo mRNA levels were measured to determine systemic effects in the kidneys and cross-tolerance effects in C and AC ischemic hearts (Langendorff, 75% ischemia, 40 min). The results demonstrated that 1) after AC, HIF-1α protein levels were increased, 2) HS alone induced transient HIF-1α upregulation, and 3) VEGF and HO1 mRNA levels increased after HS, with greater magnitude in the AC hearts. Epo mRNA in AC kidneys and EpoR mRNA in AC hearts were also elevated. In AC hearts, EpoR expression was markedly higher after HS or ischemia. Hearts from AC rats were dramatically protected against infarction after ischemia-perfusion. We conclude that HIF-1 contributes to the acclimation-ischemia cross-tolerance mechanism in the heart by induction of both chronic and inducible adaptive components.

Changes in cardiac mechanics with heat acclimation: adrenergic signaling and SR-Ca regulatory proteins

2000 ◽  
Vol 279 (1) ◽  
pp. R77-R85 ◽  
Author(s):  
Eynan Mirit ◽  
Chaya Gross ◽  
Yonathan Hasin ◽  
Aharon Palmon ◽  
Michal Horowitz
Keyword(s):  
Systolic Pressure ◽  
Cardiac Mechanics ◽  
Heat Acclimation ◽  
Regulatory Proteins ◽  
Inotropic Response ◽  
Altered Expression ◽  
Adrenergic Signaling ◽  
Plasmic Reticulum ◽  
Encoded Proteins ◽  
Steady State Levels

The involvement of adrenergic signaling and sarcoplasmic calcium regulatory proteins in the development of heat acclimation-induced adaptations in cardiac mechanics was studied in heat-acclimated (34°C) rats for 2, 5, and 30 days (AC2, AC5, and AC30, respectively). Control (C) rats were held at 24 ± 1°C. Systolic pressure (LVP) and velocities of contraction (dP/d t/P) and relaxation (−dP/d t/P) were measured using a Langendorff system. For adrenergic signaling, β-adrenoreceptor (AR) density and affinity (Scatchard plots) and cardiac inotropic response to norepinephrine (10− 7 mM, ± 10− 6 mM propranolol) were measured. For the regulatory proteins, steady-state levels of Ca2+-ATPase and phospholamban (PLB) mRNAs and the encoded proteins Ca2+-ATPase [sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)] and PLB were measured using semiquantitative RT-PCR and Western immunoblotting, respectively. Both short (STHA; AC2 and AC5)- and long-term heat acclimation (LTHA; AC30) enhanced LVP. However, dP/d t ⋅ P and −dP/d t ⋅ P in STHA hearts resembled that of the controls, whereas on LTHA, both parameters decreased ( P< 0.05), implying decreased velocity of contraction and relaxation. β-AR density remained unchanged with their affinity markedly decreased ( P < 0.05). AR responsiveness, however, diminished in AC2 but was markedly enhanced on LTHA. During STHA, PLB and sarcoplasmic reticulum Ca2+-ATPase transcripts were upregulated with no change in the encoded proteins except for SERCA downregulation on AC5, leading to an increased PLB/SERCA ratio ( P < 0.05). This mismatched preacclimation lusitropic state on STHA and increased PLB/SERCA ratio was evident ( P < 0.05) due to downregulation of SERCA and upregulation of PLB. Our data fit a biphasic acclimation model in which desensitized adrenergic signaling is dominant during STHA, whereas on LTHA, the contractile machinery is influenced by altered expression of the calcium regulatory proteins leading to both augmented adrenergic inotropic response (via PLB elevation) and decreased velocity of relaxation. The sustained low thyroxin measured on LTHA causally associates with this response.

Utilization of leucine by working rat heart

1980 ◽  
Vol 239 (6) ◽  
pp. E430-E436 ◽  
Author(s):  
K. Ichihara ◽  
J. R. Neely ◽  
D. L. Siehl ◽  
H. E. Morgan
Keyword(s):  
Oxygen Consumption ◽  
Systolic Pressure ◽  
Mechanical Activity ◽  
Cardiac Work ◽  
Threefold Increase ◽  
Rat Hearts ◽  
Langendorff Perfusion ◽  
Pressure Development ◽  
14Co2 Production ◽  
Working Rat Heart

Leucine provided substrate to partially support mechanical activity of working rat hearts; the beneficial effect on peak systolic pressure development was more marked as leucine concentration was increased to 10 mM. In Langendorff preparations that had been exposed to 5 mM [U-14C]leucine, the imposition of cardiac work was accompanied by a threefold increase in the rate of 14CO2 production within the first 30 s; however, the rate decreased 40% in the next 10 min. This transient acceleration of 14CO2 production was not observed when [1–14C]leucine was provided and appeared to be due to oxidation of a tissue pool of radioactive intermediates that was present after 10 min of Langendorff perfusion. Over a period of 1 h, oxidation of either [U-14C]- or [1–14C]leucine increased 25–40% in working compared to Langendorff preparations that were supplied 5 mM leucine and 11 mM glucose. In working hearts that were supplied a substrate and hormone mixture that simulated normal plasma and 1 mM leucine, a concentration found in the plasma of diabetic but not normal rats, leucine oxidation was accelerated 73% by work but amounted to only 3.3% of oxygen consumption.

The Mechanical Performance of Carbon Fibres- Addressing the Role of Microstructure

2019 ◽  
Author(s):  
Peter Peter ◽  
Claudia Creighton ◽  
David Fox ◽  
Pablo Mota Santiago ◽  
Adrian Hawley ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Carbon Fibres

Enteric viruses in drinking water supplies

2002 ◽  
Vol 2 (3) ◽  
pp. 17-22
Author(s):  
A.P. Wyn-Jones ◽  
J. Watkins ◽  
C. Francis ◽  
M. Laverick ◽  
J. Sellwood
Keyword(s):  
Drinking Water ◽  
Heavy Rainfall ◽  
Liquid Culture ◽  
Plaque Assay ◽  
Enteric Viruses ◽  
Enteric Virus ◽  
The Other ◽  
Raw Water ◽  
Rt Pcr ◽  
Water Supplies

Two rural spring drinking water supplies were studied for their enteric virus levels. In one, serving about 30 dwellings, the water was chlorinated before distribution; in the other, which served a dairy and six dwellings the water was not treated. Samples of treated (40 l) and untreated (20 l) water were taken under normal and heavy rainfall conditions over a six weeks period and concentrated by adsorption/elution and organic flocculation. Infectious enterovirus in concentrates was detected in liquid culture and enumerated by plaque assay, both in BGM cells, and concentrates were also analysed by RT-PCR. Viruses were found in both raw water supplies. Rural supplies need to be analysed for viruses as well as bacterial and protozoan pathogens if the full microbial hazard is to be determined.

Monitoring the marine environment for small round structured viruses (SRSVS): a new approach to combating the transmission of these viruses by molluscan shellfish

1998 ◽  
Vol 38 (12) ◽  
pp. 51-56 ◽  
Author(s):  
K. Henshilwood ◽  
J. Green ◽  
D. N. Lees
Keyword(s):  
Enteric Virus ◽  
Winter Period ◽  
Rt Pcr ◽  
Cloning And Sequencing ◽  
New Approach ◽  
Human Enteric Virus ◽  
Different Strains ◽  
The Uk ◽  
Public Health Protection

This study investigates human enteric virus contamination of a shellfish harvesting area. Samples were analysed over a 14-month period for Small Round Structured Viruses (SRSVs) using a previously developed nested RT-PCR. A clear seasonal difference was observed with the largest numbers of positive samples obtained during the winter period (October to March). This data concurs with the known winter association of gastroenteric illness due to oyster consumption in the UK and also with the majority of the outbreaks associated with shellfish harvested from this area during the study period. RT-PCR positive amplicons were further characterised by cloning and sequencing. Sequence analysis of the positive samples identified eleven SRSV strains, of both Genogroup I and Genogroup II, occurring throughout the study period. Many shellfish samples contained a mixture of strains with a few samples containing up to three different strains with both Genogroups represented. The observed common occurrence of strain mixtures may have implications for the role of shellfish as a vector for dissemination of SRSV strains. These results show that nested RT-PCR can identify SRSV contamination in shellfish harvesting areas. Virus monitoring of shellfish harvesting areas by specialist laboratories using RT-PCR is a possible approach to combating the transmission of SRSVs by molluscan shellfish and could potentially offer significantly enhanced levels of public health protection.

ROLE OF SCIENCE IN POLICY, SYSTEMS STRENGTHENING AND SUSTAINABLE SERVICE DELIVERY OF ARSENIC SAFE DRINKING WATER

2019 ◽  
Author(s):  
Prosun Bhattacharya ◽  
◽  
Md. Tahmidul Islam ◽  
Dara Johnston ◽  
Nargis Akter ◽  
...  
Keyword(s):  
Drinking Water ◽  
Service Delivery ◽  
Safe Drinking Water ◽  
Policy Systems

scholarly journals Spontaneous Retroperitoneal Hematoma in COVID-19 Severe Pneumonia–Dual-phase Multidetector Computed Tomography (MDCT) Angiogram and Role of Radiologist

2021 ◽  
Author(s):  
Vikash Kumar Gupta ◽  
Buthaina Mohammad Alkandari ◽  
Wasif Mohammed ◽  
Mohsen Ahmed Abdelmohsen ◽  
Mohammad Gaber Abdullah Mohammad
Keyword(s):  
Significant Risk ◽  
Severe Pneumonia ◽  
Retroperitoneal Hematoma ◽  
Low Molecular Weight ◽  
Rt Pcr ◽  
Prophylactic Dose ◽  
Therapeutic Anticoagulation ◽  
Coagulation Tests ◽  
Polymerase Chain

AbstractStudies available in the literature have shown alterations in blood coagulation tests in severe cases of COVID-19 pneumonia, with a significant risk of venous thromboembolism (VTE). Since microvascular thrombosis is a well-known fact in COVID-19 disease, requiring therapeutic anticoagulation, low-molecular weight heparin (LMWH) in prophylactic dose is a part of the clinical management of hospitalized COVID-19 patients. In this scenario, we describe three cases of abdominal spontaneous retroperitoneal hematoma (SRH) in hospitalized reverse transcriptase-polymerase chain reaction (RT-PCR)-confirmed COVID-19 patients.

scholarly journals The potential regulatory role of hsa_circ_0004104 in the persistency of atrial fibrillation by promoting cardiac fibrosis via TGF-β pathway

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuanfeng Gao ◽  
Ye Liu ◽  
Yuan Fu ◽  
Qianhui Wang ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Cardiac Fibrosis ◽  
Expression Patterns ◽  
In Silico Analysis ◽  
Significant Negative Correlation ◽  
Circular Rnas ◽  
Tgf Beta ◽  
Rt Pcr ◽  
Derivation Cohort ◽  
Tgf Β1

Abstract Introduction The progression of paroxysmal AF (PAF) to persistent AF (PsAF) worsens the prognosis of AF, but its underlying mechanisms remain elusive. Recently, circular RNAs (circRNAs) were reported to be associated with cardiac fibrosis. In case of the vital role of cardiac fibrosis in AF persistency, we hypothesis that circRNAs may be potential regulators in the process of AF progression. Materials and methods 6 persistent and 6 paroxysmal AF patients were enrolled as derivation cohort. Plasma circRNAs expressions were determined by microarray and validated by RT-PCR. Fibrosis level, manifested by serum TGF-β, was determined by ELISA. Pathways and related non-coding RNAs involving in the progression of AF regulated were predicted by in silico analysis. Results PsAF patients showed a distinct circRNAs expression profile with 92 circRNAs significantly dysregulated (fold change ≥ 2, p < 0.05), compared with PAF patients. The validity of the expression patterns was subsequently validated by RT-PCR in another 60 AF patients (30 PsAF and PAF, respectively). In addition, all the 5 up and down regulated circRNAs were clustered in MAPK and TGF-beta signaling pathway by KEGG pathway analysis. Among the 5 circRNAs, hsa_circ_0004104 was consistently downregulated in PsAF group (0.6 ± 0.33 vs 1.46 ± 0.41, p < 0.001) and predicted to target several AF and/or cardiac fibrosis related miRNAs reported by previous studies. In addition, TGF-β1 level was significantly higher in the PsAF group (5560.23 ± 1833.64 vs 2236.66 ± 914.89, p < 0.001), and hsa_circ_0004104 showed a significant negative correlation with TGF-β1 level (r = − 0.797, p < 0.001). Conclusion CircRNAs dysregulation plays vital roles in AF persistency. hsa_circ_0004104 could be a potential regulator and biomarker in AF persistency by promoting cardiac fibrosis via targeting MAPK and TGF-beta pathways.

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