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At least 775 records · Page 43Linked to original sources
PubMed2003

[Heat shock protein 70 induction by heat stress suppress interleukin-1beta and tumor necrosis factor-alpha levels in the brain tissue in rats with infectious brain edema].

OBJECTIVE: To investigate the changes of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in the brain tissue of rats with infectious brain edema (IBE) and their relationship with heat shock protein 70 (HSP70) by heat stress response (HSR). METHODS: Seventy-two SD rats were randomly divided into normal controls group (NS group), IBE group, and HSP group, each group was divided into three subgroups. The rats in subgroups were killed at 4 hours, 8 hours and 24 hours after the injections of IBE or normal saline respectively. HSP70 in brain tissues were determined by western blot analysis. The concentrations of IL-1beta and TNF-alpha in the brain homogenate of rats were determined by enzyme linked immunoadsorbent assay (ELISA). RESULTS: The results showed that HSP70 in brain tissues were elevated after heat shock. IBE group and NS group at 4 hours, 8 hours, 24 hours were induced to base levels of HSP70. The concentrations of TNF-alpha were significantly elevated in IBE group than in NS group at the various time points (P<0.01 or P<0.05), especially at 8 hours. The concentrations of IL-1beta were significantly increased in IBE group compared with NS group at 4 hours, 8 hours. HSR reduced the IL-1beta and TNF-alpha concentrations in the brain tissue in compared with IBE group (P<0.05 or P<0.01). CONCLUSION: IL-1beta and TNF-alpha are involved in infectious brain edema by IBE. HSP70 against infectious brain edema in rats may be associated with the reduction of IL-1beta and TNF-alpha in brain tissue.

Animals↗
PubMed1986

Effect of growth state and heat shock on nucleolar localization of the 110,000-Da heat shock protein in mouse embryo fibroblasts.

We have shown previously that the mammalian 110,000-Da heat shock protein (hsp110) associates with nucleoli in several cell types and that in 2-day postconfluent mouse 10T1/2 cells, a segregation of the antigen from the nucleolar phase-dense body is seen (J.R. Subjeck, T. Shyy, J. Shen, and R.J. Johnson. J. Cell Biol. 97: 1389-1395, 1983). Here we further characterize the nucleolar segmentation of hsp110 in mouse 10T1/2 and 3T3 cells with respect to the formation of this structure in dense cultures and investigate the behavior of this protein following conditions (serum deprivation, actinomycin D, and heat shock) known to affect the functional and morphological integrity of the nucleolus. It is shown that in addition to its nucleolar locale, an affinity of hsp110 for the nonnucleolar, nuclear compartment in actively proliferating cells is also observed. When proliferating cells are treated with actinomycin D (1 microgram/ml) for 8 h, hsp110 separates from the nucleolar phase-dense body to form a fluorescent nucleolar cap which resembles that seen in confluent cultures. This drug also results in a disappearance of hsp110 from the nucleoplasm. Incubation of cells for 24 h in media without serum also results in the nucleolar segmentation of hsp110 and a reduction in nucleoplasmic staining. A moderate nonlethal heat treatment does not lead to segmentation of hsp110 in proliferating cells but conversely results in a transient reversal of segmentation in confluent cultures. Examination of segmented nucleoli of postconfluent cells by immunoelectron microscopy reveals that hsp110 is associated with the fibrillar component of these nucleoli, the site of ribosomal DNA.

Animals↗
PubMed2004

Intracellular localization of constitutive and inducible heat shock protein 70 in rat liver after in vivo heat stress.

The level and intracellular redistribution of the two nucleo-cytoplasmic members of 70 kDa heat shock protein family (constitutive, Hsc70 or Hsp73, and inducible, Hsp72) were studied in rat liver during a 24-h period after exposure of the animals to 41 degrees C whole body hyperthermic stress. The examined proteins were detected in the liver cytosol and nuclei by Western blotting and immunohistochemical staining of paraffin sections, as well as by immnocytochemical staining of isolated nuclear smears. All three techniques applied were based on the use of monoclonal antibodies recognizing both constitutive and inducible Hsp70 isoforms or only the inducible isoform, and gave consistent results. The exposure of the animals to in vivo heat stress was shown to induce the synthesis of otherwise non-existing Hsp72, rendering Hsc70 level unchanged in comparison to unstressed controls. However, immediately after the stress the intracellular redistribution of Hsc70, i.e. its nuclear accumulation, was observed. The maximal level of Hsp70 both in the cytoplasm and in the nuclei was registered 5 h after the stress, which coincided with the maximal level of Hsp72 induction. The alterations in the level and intracellular distribution of examined proteins were still noticeable 24 h after the stress. The results of this study could shed some more light on, as yet uncertain, differences between cellular functions of these two proteins, as well as on the role of the constitutive form under normal and stress conditions.

Animals↗
PubMed2001

Heat-shock factor-1, steroid hormones, and regulation of heat-shock protein expression in the heart.

Heat-shock proteins (HSPs) are an important family of endogenous, protective proteins. Overexpression of HSPs is protective against cardiac injury. Previously, we observed that dexamethasone activated heat-shock factor-1 (HSF-1) and induced a 60% increase in HSP72 in adult cardiac myocytes. The mechanism responsible for this effect of dexamethasone is unknown. Because HSP90 is known to bind the intracellular hormone receptors, we postulated that the interaction between HSP90, the receptors, and HSF was an important element in activation of HSF-1 by hormones. We hypothesized that there is an equilibrium between HSP90 and the various receptors/enzymes that it binds and that alteration in levels of certain hormones will alter the intracellular distribution of HSP90 and activate HSF-1. We report that, in adult cardiac myocytes, HSF-1 coimmunoprecipitates with HSP90. HSP90 redistributes in cardiac myocytes after treatment with 17beta-estradiol or progesterone. Estrogen and progesterone activate HSF-1 in adult male isolated cardiac myocytes, and this is followed by an increase in HSP72 protein. Testosterone had no effect on HSP levels; however, no androgen receptor was found in cardiac myocytes; therefore, testosterone would not be expected to effect binding of HSP90 to HSF. Geldanamycin, which inactivates HSP90 and prevents it from binding to receptors, activates HSF-1 and stimulates HSP72 synthesis. Activation of HSF-1 by steroid hormones, resulting from a change in the interaction of HSP90 and HSF-1, represents a novel pathway for regulating expression of HSPs. These findings may explain some of the gender differences in cardiovascular disease.

Animals↗
PubMed1998

Whole body heat shock fails to protect mouse heart against ischemia/reperfusion injury: role of 72 kDa heat shock protein and antioxidant enzymes.

The transgenic mice overexpressing heat shock protein 72 (HSP72) or antioxidants have been reported to be more resistant to myocardial ischemia/reperfusion injury. However, it remains unknown whether whole body heat stress (HS) which may induce HSP72 or endogenous antioxidants affords similar protection in the mouse heart. Adult male mice were treated with either HS (42 degrees C for 15 min) or anesthesia only (SC) against a group of non-stressed controls (NC). At 6 or 24 h later, the hearts were excised and perfused at a constant pressure of 55 mmHg in Langendorff mode. Following 30 min equilibration, hearts were subjected to 20 min of global ischemia and 30 min reperfusion (37 degrees C). Ventricular force was measured by a force-displacement transducer attached to the apex. Leakage of intracellular enzymes (CK, LDH) was measured in coronary efflux. Infarct size was determined by tetrazolium staining. The results showed that no significant differences between HS, SC, and NC groups in ventricular contractile function, CK and LDH release, or infarct size were observed at either time window. HS enhanced the expression of HSP72 in mouse hearts by two- to three-fold, whereas antioxidant enzyme activities (catalase and MnSOD) did not change significantly. We conclude that HS does not precondition the isolated perfused mice hearts against ischemia/reperfusion injury, despite induction of HSP72.

Animals↗
PubMed1992

Physical interaction between heat shock proteins DnaK, DnaJ, and GrpE and the bacterial heat shock transcription factor sigma 32.

Genetic evidence indicates central roles for Hsp70 chaperones in the regulation of heat shock gene expression. This regulatory function has been postulated for Escherichia coli to rely on the direct association of DnaK (Hsp70) with the heat shock transcription factor sigma 32. This report presents evidence for the physical association of DnaK, DnaJ, and GrpE chaperones with sigma 32 in vivo. Surprisingly, an interaction of DnaJ with sigma 32 exists that is distinguishable from an interaction of DnaK and GrpE with sigma 32: addition of ATP disrupts the association of DnaK and GrpE with sigma 32, but not the association of DnaJ with sigma 32. Furthermore, DnaJ-sigma 32 and DnaK-sigma 32 associations occur independent of DnaK and DnaJ, respectively. These results suggest distinct regulatory functions of DnaJ and DnaK/GrpE.

Adenosine Triphosphatases↗
PubMed2004

The effect of dietary phosphorus on heat shock protein mRNAs during acute heat stress in male broiler chickens (Gallus gallus).

A 2 x 2 factorially arranged completely randomized experimental design was used to study the relationship between inorganic phosphorus (Pi) and heat shock protein (HSP) mRNA expression in different organs of commercial broiler cockerels during acute heat stress (HS). Brain, heart, liver and spleen were assayed for hsp70, hsp90alpha and hsp90beta mRNA. At 1 day of age, chickens were assigned randomly to two dietary Pi treatment groups (Pi-: 0.16%; Pi+: 0.5%). At 3 weeks of age, half of the chickens in each Pi group were subjected to HS (Ta=41 degrees C, 60 min) while the other half was maintained in a thermoneutral environment (CN, Ta=25 degrees C). The results showed inter-organ variation in the expression of HSP mRNAs. Brain expressed the most HSP mRNAs while spleen expressed the least. When broilers were subjected to HS, the expression of HSP mRNAs was influenced positively by the consumption of the Pi+ diet. However, analysis of variance revealed that Ta influenced HSP transcription more than phosphorus availability. Thermal stress caused induction of hsp90alpha and hsp90beta in heart, liver and spleen, but hsp90alpha and hsp9beta mRNA levels were stable in brain. Transcription of hsp70 increased (P< or =0.05) in all organs from chickens in HS groups when compared to chickens in CN groups. Although Pi+ did not show any significant increases in the expression of hsp mRNAs, there were consistently larger HSP mRNA values in liver and spleen tissues. The high expression of hsp90alpha and hsp90beta in brain of chicks in both CN and HS conditions could be due to the involvement of hsp90 in steroid hormone receptors or the high metabolic activity of neurons in the central nervous system.

Animal Feed↗
PubMed2000

Acute pancreatitis results in induction of heat shock proteins 70 and 27 and heat shock factor-1.

Heat shock proteins (HSPs) 70 and 27 are stress-responsive proteins that are important for cell survival after injury; the expression of these HSPs is regulated primarily by the transcription factor heat shock factor-1 (HSF-1). The purpose of this study was to determine the effect of acute pancreatitis on pancreatic HSPs (70, 27, 60, and 90) expression and to assess potential mechanisms for HSP induction using a murine model of cerulein-induced pancreatitis. We found an increase of both HSP70 and HSP27 levels with expression noted throughout the pancreas after induction of pancreatitis. HSP60 and HSP90 levels were constitutively expressed in the pancreas and did not significantly change with acute pancreatitis. HSF-1 DNA binding activity increased in accordance with increased HSP expression. We conclude that acute pancreatitis results in a marked increase in the expression of HSP70 and HSP27. Furthermore, the induction of HSP70 and HSP27 expression was associated with a concomitant increase in HSF-1 binding activity. The increased expression of both HSP70 and HSP27 noted with pancreatic inflammation may confer a protective effect for the remaining acini after acute pancreatitis.

Acute Disease↗
PubMed2002

Regulation of heat shock proteins, Hsp70 and Hsp64, in heat-shocked Malpighian tubules of Drosophila melanogaster larvae.

It is known from earlier studies that the heat shock (HS) response in Malpighian tubules (MTs) of Drosophila larvae is different from that in other tissues because instead of the Hsp70 and other common heat shock proteins, Hsp64 and certain other new proteins are induced immediately after HS. In the present study, we examined the kinetics of the synthesis of Hsp70 and Hsp64 immediately after HS and during recovery from HS by 35S-methionine labeling and Western blotting. In addition, we also examined the transcriptional activity of hsp70 genes in larval MT cells at different times after HS by in situ hybridization and Northern blotting. The HS-induced synthesis of Hsp64 ceased by 1 hour of recovery from the HS when synthesis of the Hsp70 commenced. Our results revealed that the induced synthesis of Hsp64 immediately after HS was dependent on new transcription. Although the levels of Hsp70 in MT cells rapidly increased after its synthesis began during recovery, the levels of Hsp64 remained unaltered irrespective of its new synthesis occurring during or after HS. Inhibition of new Hsp64 synthesis by transcriptional or translational inhibitors also did not affect the total amount of this protein in MTs. The Hsp64 polypeptides synthesized in response to HS are degraded rapidly. Apparently, the cells in MTs maintain a balance between new synthesis of Hsp64 and its turnover so that under all conditions a more or less constant level of this protein is maintained. Although the Hsp70 synthesis started only after 1 hour of recovery, the hsp70 genes were transcriptionally activated immediately after HS and they continued to transcribe till at least 4 hours after the HS. The hsp70 transcripts in MT cells that recovered for 2 hours or longer did not contain the 3' untranslated regions (UTRs), which may allow their longer stability and translatability at normal temperature. Synthesis of Hsp70 during recovery period was dependent on continuing transcription. Assessment of the beta-galactosidase activity in 2 transgenic lines carrying the LacZ reporter gene under hsp70 promoter and different lengths of the 5'UTR suggested that the delayed translation of hsp70 transcripts in MTs is probably regulated by some elements in the 5'UTR.

3' Untranslated Regions↗
PubMed2002

The receptor for heat shock protein 60 on macrophages is saturable, specific, and distinct from receptors for other heat shock proteins.

Previous studies have shown that human heat shock protein (hsp) 60 elicits a strong proinflammatory response in cells of the innate immune system with CD14, Toll-like receptor (TLR) 2, and TLR4 as mediators of signaling, but probably not of binding. In the present study, we directly demonstrate binding of hsp60 to the macrophage surface and find the binding receptor for hsp60 different from the previously described common receptor for several other heat shock proteins, including hsp70, hsp90, and gp96. Fluorescence-labeled human hsp60 bound to cell surfaces of the murine macrophage lines J774 A.1 and RAW264.7 and to mouse bone marrow-derived macrophages. By flow cytometry, we could demonstrate for the first time that hsp60 binding to macrophages occurred at submicromolar concentrations, is saturable, and can be competed by unlabeled hsp60, but not by unrelated proteins, thus confirming the classic characteristics of specific ligand-receptor interactions. Binding of hsp60 at 4 degrees C was followed by endocytosis at 37 degrees C. Hsp60 binding to macrophages could not be competed by excess hsp70, hsp90, or gp96, all of which share the alpha(2)-macroglobulin receptor as binding site. Hsp60 binding occurred in the absence of surface TLR4. However, no cytokine response was induced by hsp60 in TLR4-deficient macrophages. We conclude that hsp60 binds to a stereo-specific receptor on macrophages, and that different surface molecules are engaged in binding and signal transduction. Furthermore, the binding site for hsp60 is separate from the common receptor for hsp70, hsp90, and gp96, which suggests an independent role of hsp60 as danger Ag and in immunoregulation.

Animals↗
PubMed2003

Proteomic analysis of the effect of heat stress on hexaploid wheat grain: Characterization of heat-responsive proteins from total endosperm.

High temperatures during grain filling have been reported to be one of the factors that can affect the dough properties and quality characteristics of wheat. Responses to high temperature have been related to changes in protein composition at both quantitative and qualitative levels. The present study was conducted to determine the influence of high temperature during grain filling on the protein composition of bread wheat evaluated by proteomic tools. Plants were grown in the field and transferred to cabinets soon after flowering. They were subjected to two thermal regimes 18 degrees C/10 degrees C (day/night) and 34 degrees C/10 degrees C. Total proteins were extracted from control grains and treated plants at three different post-anthesis stages. The proteins were separated by two-dimensional gel electrophoresis and analysed by Melanie 3 software. Of the total number of mature wheat grain proteins, 37 were identified as significantly changed by heat treatment. Analysis by matrix-assisted laser desorption/ionization mass spectrometry and tandem mass spectrometry coupled with database searching allowed the characterization of 25 heat-induced proteins and only one heat-decreased protein spot. To learn more about the function of the identified proteins, we examined their expression during treatment.

Chromatography, High Pressure Liquid↗
PubMed1978

The products of the "heat-shock" loci of Drosophila hydei. Correlation between locus 2-36A and the 70,000 MW "heat-shock" peptide.

Antibody was raised against total Drosophila hydei embryonic cellular protein with a molecular weight between 65,000 and 70,000 dalton. This antiserum reacted with the 70,000 MW "heat-shock" peptide found in "S labelled cell extracts of "heat-shocked" D. hydei tissue culture cells or salivary glands.--The antibody was coupled to Sepharose 4B and this material was used to absorb polysomes obtained from tissue culture cells incubated at 37 degrees C in the presence of tritiated RNA precursors. The relative concentrations of various RNA species complementary to the "heat-shock" loci 2-32A, 2-36A, and 2-48C in either bound, non-bound, or total polysomal material was then determined by in situ hybridization. The RNA species complementary to locus 2-36A was found to be enriched in the bound polysomal material.

Animals↗
PubMed1986

Skin and core temperatures as determinants of heat production and heat loss in the goat.

In 82 experiments on 10 goats body core temperature (Tcore) was altered between 35 degrees and 42 degrees C by external heat exchangers acting on blood temperature while skin temperature (Tskin) was maintained constant, by a circulating shower bath, at different levels between 32 degrees and 44 degrees C. At all skin temperatures at least fourfold increases of heat production (M) and respiratory evaporative heat loss (REHL) occurred when Tcore was lowered or raised, respectively. The lower Tskin was, the higher were the thresholds of Tcore, at which M or REHL exceeded resting levels. The lower Tskin was, the higher were the slopes, at which M or REHL changed per unit of Tcore. At a given Tskin, the slopes decreased with increasing M or REHL, and were dependent on the range of Tcore. The higher the range of Tcore, the steeper changed M and REHL with changing Tcore, if all other variables were held constant. The results support the concept that an exponential relationship between Tcore and the rate of core temperature signals is the primary cause of the effects exerted by Tskin on the slopes, at which M or REHL change per unit of Tcore.

Animals↗
PubMed1980

Intraventricular administration of isoproterenol inhibits both heat production and heat loss mechanisms in rats.

At an ambient temperature (Ta) of 8 degrees C, intraventricular administration of isoproterenol inhibited metabolic heat production and led to hypothermia in rats. In contrast, at a Ta of 22 degrees C and of 30 degrees C, isoproterenol decreased cutaneous circulation and led to hyperthermia. The data indicate that isoproterenol inhibits both heat production and heat loss mechanisms in rats.

Animals↗
PubMed1999

Determination of airway humidification in high-frequency oscillatory ventilation using an artificial neonatal lung model. Comparison of a heated humidifier and a heat and moisture exchanger.

OBJECTIVE: Thus far only few data are available on airway humidification during high-frequency oscillatory ventilation (HFOV). Therefore, we studied the performance and efficiency of a heated humidifier (HH) and a heat and moisture exchanger (HME) in HFOV using an artificial lung model. METHODS: Experiments were performed with a pediatric high-frequency oscillatory ventilator. The artificial lung contained a sponge saturated with water to simulate evaporation and was placed in an incubator heated to 37 degrees C to prevent condensation. The airway humidity was measured using a capacitive humidity sensor. The water loss of the lung model was determined gravimetrically. RESULTS: The water loss of the lung model varied between 2.14 and 3.1 g/h during active humidification; it was 2.85 g/h with passive humidification and 7.56 g/h without humidification. The humidity at the tube connector varied between 34. 2 and 42.5 mg/l, depending on the temperature of the HH and the ventilator setting during active humidification, and between 37 and 39.9 mg/l with passive humidification. CONCLUSION: In general, HH and HME are suitable devices for airway humidification in HFOV. The performance of the ventilator was not significantly influenced by the mode of humidification. However, the adequacy of humidification and safety of the HME remains to be demonstrated in clinical practice.

Artificial Organs↗
PubMed2000

Comparison of open microwave digestion and digestion by conventional heating for the determination of Cd, Cr, Cu and Pb in algae using transverse heated electrothermal atomic absorption spectrometry.

A comparison between open microwave digestion and digestion by conventional heating was carried out for the determination of Cd, Cr, Cu, and Pb in two algae matrices using transverse heated electrothermal atomic absorption spectrometry (ETAAS). A SRM GBW 08504 cabbage was also analysed. These matrices were digested with HNO3, using a quartz vessel for microwave digestion and PFA vessel for digestion by conventional heating. Cd, Cu and Cr were determined without any modifier, while magnesium nitrate and ammonium phosphate mixed modifier was used for Pb. Results obtained by both the procedures were in good agreement with each other at 95% confidence level, and for SRM GBW 08504 cabbage the values agree well with the certified values. The limits of detection obtained were 0.0004, 0.060, 0.065 and 0.054 mg/kg for Cd, Cr, Cu, and Pb, respectively, using the microwave digestion process. The RSD for Cd was 10-15% and for the other elements 5-10%.

Bryopsida↗
PubMedDate not supplied

Heat of sorption induced by sweating affects thermoregulatory responses during heat load.

To investigate the effects of heat of sorption per se induced by sweating on thermoregulatory responses in clothed subjects, two experiments were carried out. In experiment 1 [ambient temperature (Ta) 27.2 degrees C, 50% relative humidity (r.h.)], seven female subjects immersed their lower-legs in a water bath at a temperature raised between 35-41 degrees C during 70 min wearing garments made for the experiment of either 100% cotton (C) or 100% polyester (P). Skin blood flow at the forearm was significantly greater in C than in P (P < 0.05). The increase of mean skin temperature (Tsk) and clothing surface and clothing microclimate temperatures were significantly higher in C than that of P after the onset of sweating (P < 0.05). Furthermore, these responses were accompanied by warmer and more uncomfortable sensations in C than in P despite a lower rectal temperature in C compared with P and identical mean body temperature in both sets of garments. In experiment 2, to simulate the clothing microclimate after the onset of sweating, C and P garments were exposed in the climate chamber to r.h. raised from 50% to 95% at a constant Ta of 27.2 degrees C. The clothing surface temperature rose by 2.2 degrees C for C and by 0.5 degree C for P after the increase of r.h. These results clearly showed a more marked increase in heat of sorption in C than in P. These results indicated that the heat of sorption per se after the onset of an increasing clothing microclimate vapour pressure, mimicking the onset of sweating, enhanced thermoregulatory responses such as skin blood flow, (Tsk) and subjective voting in C.

Adult↗
PubMed1992

Estimation of heat stress in Tanzania by using ISO heat stress indices.

The aim of this study was to evaluate the usefulness of the ISO heat stress standards in estimating the heat stress and strain in workplaces in Tanzania. Another aim was to select and to develop simplified methods for measuring physiological parameters in developing countries. The methods were tested in four hot factories and at a construction site. It seems that in tropical working environments the climatic conditions for which the ISO 7933 standard is applicable are too narrow. For instance, the mean skin temperature was incorrectly estimated by ISO 7933. An approximate analysis of the working situation can nevertheless be carried out by assuming the mean skin temperature to be 34.5 degrees C. During the study, heat stress and strain were not as high as expected; deep body temperatures were usually lower than 38 degrees C, sweat rates lower than 400 g/h and heart rates below 100 beats/min for about 72% of the measuring time. This is due to the job rotation of the workers and the long rest periods, because the number of workers is large in the factories, and the weather was not at its hottest during the survey.

Journal Article↗