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PubMed1997

Heat shock proteins and heat adaptation of the whole organism.

Adaptation to heat may occur through acclimatization or thermotolerance; however, the linkage of these phenomena is poorly understood. The importance of heat shock proteins (HSPs) in thermotolerance and differences in their accumulation in organisms adapted to the heat suggest a role for HSPs in acclimatization as well. The role of HSPs in heat adaptation of the whole organism and the interrelationships among heat adaptation, endotoxin tolerance, and cytokine resistance through HSPs are reviewed.

Acclimatization↗
PubMed1986

A heat shock-resistant variant of Chinese hamster cell line constitutively expressing heat shock protein of Mr 90,000 at high level.

A heat shock-resistant variant of Chinese hamster cell line (CHO) was isolated from ethane methane sulfonate-treated CHO cells through selection by repeated exposures to elevated temperature. The variant, designated HR-01, was one to two order of magnitudes more resistant to lethal heat shock (46.0 degrees C) than the parental CHO strain (p-CHO). The heat shock resistance characteristic of this variant was stable. In addition, the HR-01 variant showed more elongated cell morphology, and was more adherent to substrate than p-CHO. When total proteins of p-CHO and HR-01 cells were compared in two-dimensional polyacrylamide gel electrophoresis, HSP90, a heat shock protein of Mr 90,000, was found to be the only protein that was expressed at a significantly higher level in HR-01 cells than in p-CHO cells. Because of the known intriguing molecular properties of HSP90, the HR-01 variant would be useful for further investigation of functions of HSP90 as well as the mechanism of acquiring heat shock resistance in mammalian cells.

Animals↗
PubMedDate not supplied

Heat does not induce synthesis of heat shock proteins or thermotolerance in the earliest stage of mouse embryo development.

To study a possible role of HSP in the thermal response of mouse embryos, we examined heat survival and HSP synthesis of mouse embryos at the one-cell stage or the blastocyst stage. One-cell embryos were extremely heat sensitive and synthesized HSP at very low levels or not at all. At that developmental stage neither thermotolerance nor HSP synthesis could be induced by heat shock. In contrast, unheated blastocysts synthesized HSP constitutively, were comparatively heat resistant, and both thermotolerance and enhanced rate of HSP synthesis were induced by a non-lethal heat exposure. Our data demonstrate a correlation between HSP synthesis, thermal sensitivity and thermotolerance in this system, and strengthen the suggestion that gene activation of HSP synthesis is closely related to the differentiation process.

Animals↗
PubMedDate not supplied

Temperature-dependency of the expression of heat shock proteins in rat hepatoma cells with a different degree of heat sensitivity.

Of two rat hepatoma cell lines, Reuber H35 and HTC, with a different degree of differentiation and heat sensitivity, treated at 41-44 degrees C for various periods of time, the expression of thermotolerance, recovery of protein synthesis and rate of hsp synthesis were studied in relation to heat-induced cell killing. The temperature dependency of the induction of thermotolerance, either chronic or acute, was different between the cell lines; tolerance of H35 cells being induced at lower temperature than that of HTC cells. Induction of thermotolerance was related to survival decrement and the correlation was similar for both cell lines. Protein syntheses of H35 and HTC cells are equally sensitive for incubation at increased temperature, but recovery of protein synthesis after heat treatment was slightly different between the cell lines; H35 being more delayed than HTC. A strong but different correlation between total amount of protein synthesized after heat treatment and cell survival was found for the two cell lines. The increased heat sensitivity of H35 cells parallels the increased capacity of selective hsp synthesis as compared with that of HTC cells.

Animals↗
PubMed1992

Heat-shock protein synthesis in chicken macrophages: influence of in vivo and in vitro heat shock, lead acetate, and lipopolysaccharide.

Synthesis of heat-shock proteins (HSP) in chicken macrophages, in response to thermal and nonthermal stressors, was determined. Cornell K-strain 6-wk-old White Leghorn females were injected with Sephadex and approximately 42 h later subjected to elevated temperatures in order to achieve a core body temperature (CBT) of 44 C. Peritoneal macrophages were isolated at 30 and 60 min after heat treatment. A parallel group of chickens, maintained at the normal CBT of 41 C, was used as controls and peritoneal macrophages were isolated after 60 min of treatment. For in vitro study of HSP response, cells of a chicken macrophage cell line (MQ-NCSU) were subjected to 45 C ambient temperature to produce heat shock (HS, thermal stress), lipopolysaccharide (LPS, 15 micrograms), and lead acetate (nonthermal stress) exposure for varying time periods. The HSP profiles of macrophages following various treatments were determined by one- and two-dimensional gel electrophoresis. The results showed that macrophages isolated from the 44 C CBT group synthesized HSP90, HSP70, HSP23, and a heat-inducible P32 protein. This HSP synthesis profile was similar to the HSP expression by MQ-NCSU cells exposed in vitro to 45 C conditions. Exposure to MQ-NCSU cells to lead acetate induced the same four proteins previously expressed by macrophages after in vivo or in vitro heat treatment. Two-dimensional analysis of lysates from cells treated with LPS, HS, or LPS plus HS treatments revealed a doublet protein molecule (70a and 70b) with identical molecular mass of 70 kDa. However, the pI value (isoelectric point) of 70b was higher (5.1) than that of 70a, which, along with HSP90 and HSP23, focused more toward the acidic side with a pI value of less than 4.6. The present study is the first to report pI profiles of chicken macrophage HSP. The in vitro and in vivo studies suggest that chicken macrophages respond to thermal and nonthermal stressors by producing similar kinds of "stress proteins".

Animals↗
PubMed1998

Near-fatal heat stroke during the 1995 heat wave in Chicago.

BACKGROUND: In July 1995, Chicago sustained a heat wave that resulted in more than 600 excess deaths, 3300 excess emergency department visits, and a substantial number of intensive care unit admissions for near-fatal heat stroke. OBJECTIVE: To describe the clinical features of patients admitted to an intensive care unit with near-fatal classic heat stroke. Patients were followed for 1 year to assess delayed functional outcome and mortality. DESIGN: Observational study. SETTING: Intensive care units in the Chicago area. PATIENTS: 58 patients admitted to the hospital from 12 July to 20 July 1995 who met the case definition of classic heat stroke. MEASUREMENTS: The data collection tool was designed to compile demographic and survival data and to permit analysis of organ system function by abstracting data on physical examination findings, electrocardiography and echocardiography results, fluid resuscitation, radiography results, and laboratory findings. Data on functional status at discharge and at 1 year were collected by using a modified Stanford Health Assessment Questionnaire. RESULTS: Patients experienced multiorgan dysfunction with neurologic impairment (100%), moderate to severe renal insufficiency (53%), disseminated intravascular coagulation (45%), and the acute respiratory distress syndrome (10%). Fifty-seven percent of patients had evidence of infection on admission. In-hospital mortality was 21%. Most survivors recovered near-normal renal, hematologic, and respiratory status, but disability persisted, resulting in moderate to severe functional impairment in 33% of patients at hospital discharge. At 1 year, no patient had improved functional status, and an additional 28% of patients had died. CONCLUSIONS: Near-fatal classic heat stroke is associated with multiorgan dysfunction. A high percentage of patients had infection at presentation. A high mortality rate was observed during acute hospitalization and at 1 year. In addition, substantial functional impairment at discharge persisted 1 year. The degree of functional disability correlated highly with survival at 1 year.

Adult↗
PubMedDate not supplied

[Changes in water electric conductivity upon heating by various heat sources including biological objects].

The temperature dependence of conductivity of water heated by a biological object, as well as electrical, aqueous and other types of heaters was studied. Substantial differences in the conductivity parameters of water heated by bioobjects and physical sources of heat were found. The effect of "memory" of water in response to the biological influence and differences in the entropy of water upon biological treatment and upon heating by physical sources of heat were revealed.

Algorithms↗
PubMed2005

Induction of heat shock protein 72 in C6 glioma cells by methyl jasmonate through ROS-dependent heat shock factor 1 activation.

Salicylate and jasmonates are two different types of plant hormone that play critical roles in plant defense responses against insect herbivores and microbial pathogens, through activating defense genes. These two natural products have been shown to have similar activities in animal cells: the compounds are able to induce cell cycle arrest or apoptosis in a variety of human cancer cells including those of colon, prostate, breast, and leukemia, suggesting the chemicals may potentially be a novel class of anti-cancer drugs. Since sodium salicylate can induce the heat shock response in animals, we examined the effects of jasmonates on the heat shock response in C6 glioma cells. Here, we show that brief exposure to methyl jasmonate (MeJA), but not to jasmonic acid, induces heat shock protein 72 (HSP72), but not HSP73 and HSP90, via heat shock factor I (HSF1) activation in C6 glioma cells without affecting cell viability. Intracellular H2O2 and O2-, and mitochondrial ROS were prominently increased in response to 5 mM MeJA in C6 cells. MeJA-induced HSP72 expression, HSF1 DNA binding, and human HSP70 promoter-driven CAT activity were prevented by N-acetyl-L-cysteine (a general antioxidant), catalase (a specific antioxidant for H2O2), and sodium formate (an inhibitor of OH.), but not by Rac1 dominant negative mutant Rac1N17 and diphenyleneiodonium (a NADPH oxidase inhibitor), indicating that MeJA induces HSP72 expression though HSF1 that is activated via Rac1-NADPH oxidase-independent ROS production pathway. These results suggest that the plant stress hormones share the ability to induce heat shock response in animal cells.

Acetates↗
PubMed1988

Investigation of the effects of heat shock and agents which induce a heat shock response on the induction of differentiation of HL-60 cells.

A heat shock of 42.5-43.5 degrees C for 1 h applied to HL-60 promyelocytic leukemia cells induced the appearance of between 13 and 34% (n = 6) of cells which showed characteristics of mature metamyelocytes/granulocytes. This is the first time a physical agent has been shown to induce the differentiation of this leukemic cell line. The treatment of HL-60 cells with a variety of agents which have been documented to stress cells and induce thermotolerance or a heat shock-like response also induced granulocyte-like differentiation: continuous treatment for 4 days with ethanol (213 mM), sodium arsenite (6 microM), cadmium sulfate (60 microM), lidocaine (3 mM), and procaine (5 mM) induced 73, 54, 14, 54, and 55% of cells, respectively, to reduce the dye nitro blue tetrazolium. They were also capable of the phagocytosis of yeast particles. Examination of differentiated cells showed that those treated with ethanol, arsenite, lidocaine, and procaine also expressed nonspecific esterase activity, typical of monocytes, but did not adhere to plastic and had a cellular and nuclear morphology consistent with differentiation to metamyelocytes. Analysis of protein synthesis of HL-60 cells treated with 170 mM N-methylformamide, by the pulse labeling of cells for 2 h with [14C]leucine at various times, showed that the constitutive synthesis of both the Mr 90,000 and 70,000 heat shock proteins fell substantially after 2 h of exposure to N-methylformamide. When HL-60 cells were incubated with 1 M N-methylformamide, a toxic concentration of this agent, or were heat shocked, the synthesis of both the Mr 70,000 and Mr 90,000 proteins was induced. We propose that changes in heat shock protein synthesis may be an important element of the induction of differentiation of HL-60 cells, particularly as these proteins have recently been shown to regulate the stability of oncogene proteins, such as myc (Lüscher, B., and Eisenman, R. N., Mol. Cell Biol., 8: 2504-2512, 1988).

Cell Differentiation↗
PubMed1988

The effect of heat shock on primary cultures of brain capillary endothelium: inhibition of assembly of zonulae occludentes and the synthesis of heat-shock proteins.

Subjecting primary cultures of bovine brain microvessel endothelial cells to thermal stress (heat shock) results in: (1) an inhibition of further tight junction assembly, (2) the disappearance and/or disassembly of tight junctions, (3) a 30-fold increase in the number of plasmic fracture (PF)-face intramembrane particles, and (4) the new and/or enhanced synthesis of at least three heat-shock polypeptides (HSPs) with molecular masses of approximately 100,000, 90,000 and 70,000. Endothelial cells which are heat-shocked and allowed to recover at 37 degrees C exhibit, within the first 2 h, a marked depression in the synthesis of HSPs and the new and/or enhanced synthesis of a 47,000 dalton "recovery" polypeptide. In later periods of recovery (2-4 h), the synthesis of this polypeptide is even more pronounced and is accompanied by the new and/or enhanced synthesis of a polypeptide(s) with a molecular mass of 35 to 37,000. The appearance of these "recovery protein(s)" in the endothelial cells is concomitant with a decrease in the number of PF-face intramembrane particles and the resumption of tight junction assembly. Results of this study suggest that some of the HSPs synthesized by thermally-stressed cultures of brain endothelial cells may activate or be directly involved in a mechanism(s) to ensure survival of these cells by decreasing membrane fluidity and stabilizing the plasma membrane of these cells. Moreover, our results also suggest that the recovery of these cells from the stress of heat shock is accompanied by the synthesis of "recovery" proteins which, in some manner, may be directly involved in, or necessary for, rapidly reversing the membrane-stabilizing effect of heat shock by promoting membrane fluidity and the apparent amplified synthesis and assembly and/or reassembly of tight junctions.

Animals↗
PubMed1993

Transient activation of a distinct serine protein kinase is responsible for 27-kDa heat shock protein phosphorylation in mitogen-stimulated and heat-shocked cells.

We have investigated the phosphorylation of HSP27, a 27-kDa heat shock protein which is involved in cellular thermoresistance and is also an early target of phosphorylation during heat shock and cell stimulation by a variety of growth and differentiation factors. HSP27 is transiently phosphorylated after shifting Chinese hamster cells from their normal temperature of 37 to 44 degrees C. The phosphorylation correlated in time with the transient activation of specific HSP27 protein kinase activities. HSP27 kinase was also induced to maximal levels within 5-15 min following stimulation of quiescent cells with heat shock, serum, thrombin, or basic fibroblast growth factor. Extracts from quiescent cells stimulated by heat shock or serum were analyzed after sequential chromatography on cation exchange and hydroxylapatite columns. In both cases, a single and identical peak of HSP27 kinase activity was obtained, suggesting that the same protein kinase was induced. The HSP27 kinase efficiently phosphorylated recombinant Chinese hamster HSP27 or the synthetic peptide RALNRQLSSGV containing the major in vivo phosphorylation site of rodent HSP27. The kinase was inactive toward the ribosomal S6 protein, the peptide RALSSLRA from S6 protein, or the mutant HSP27 proteins with in vivo phosphorylation sites altered to glycine. The partially purified HSP27 kinase had no kinase C, kinase A, or S6 kinase activities; conversely, HSP27 was not a good substrate for these kinases. HSP27 kinase was rapidly inactivated in the presence of acid phosphatase, suggesting that its activity was regulated by phosphorylation. It is suggested that this heat shock- and serum-induced HSP27 kinase is a novel serine kinase which is linked to a major signal transduction cascade.

Acid Phosphatase↗
PubMed1977

Exercise and heat orthostatism and the effect of heat acclimation and physical fitness.

Twelve trained and 16 untrained young men were administered five orthostatic tests while leaning upright against a wall, for 20 min--before exercise; after 60 min of exercise at a load of 40 W; after 15 min of exercise at a load of 80 W; after a Vo2 max test, and after 3 h of exercise at a load of 40 W in heat (39.4 degrees C DB, 30.3 degrees C WB). Eight of the untrained subjects were retested in the five orthostatic tests after 8 d of heat acclimation. The number of fainters in the orthostatic tests administered before exercise, after exercise at 40 W and 80 W, and after exercise in heat, were 3, 4, 6, and 13, respectively. There were no fainting episodes after the Vo2 max tests. Orthostatic responses in the different conditions were partially related. The trained subjects showed substantially better responses than the untrained ones (10% vs. 25% of fainting episodes), and heat acclimation resulted in marked improvement in orthostatism (decrease to 5% faintings). The results show that Vo2 max and heat tolerance account for most of the variability which determines orthostatic tolerance.

Acclimatization↗
PubMed1997

Quercetin inhibits heat shock protein induction but not heat shock factor DNA-binding in human breast carcinoma cells.

The flavonoid quercetin inhibits the heat-induced synthesis of heat shock proteins (hsps) in a variety of cell lines. To determine whether quercetin could inhibit hsp expression in breast cancer cells, we used the human breast cancer cell line, MDA-MB-231. Treatment of these cells with quercetin decreased the heat-induced synthesis of hsp27 and hsp70. However, inhibition of hsp expression did not correspond with the reduced ability of heat shock transcription factors (HSFs) to bind DNA. Furthermore, while quercetin treatment inhibited HSF2 expression, it only slightly affected HSF1 expression in breast cancer cells. In contrast, quercetin inhibited both HSF DNA-binding activity and HSF expression in HeLa cells. Our studies suggest that quercetin's action is cell-type specific, and in breast cancer cells may involve regulation of HSF transcriptional activity, rather than regulation of its DNA-binding activity.

Binding Sites↗
PubMed2003

Bimoclomol, a heat shock protein co-inducer, acts by the prolonged activation of heat shock factor-1.

The novel hydroxylamine derivative, bimoclomol, has been shown previously to act as a co-inducer of several heat shock proteins (Hsp-s), enhancing the amount of these proteins produced following a heat shock compared to heat shock alone. Here we show that the co-inducing effect of bimoclomol on Hsp expression is mediated via the prolonged activation of the heat shock transcription factor (HSF-1). Bimoclomol effects are abolished in cells from mice lacking HSF-1. Moreover, bimoclomol binds to HSF-1 and induces a prolonged binding of HSF-1 to the respective DNA elements. Since HSF-1 does not bind to DNA in the absence of stress, the bimoclomol-induced extension of HSF-1/DNA interaction may contribute to the chaperone co-induction of bimoclomol observed previously. These findings indicate that bimoclomol may be of value in targeting HSF-1 so as to induce up-regulation of protective Hsp-s in a non-stressful manner and for therapeutic benefit.

Animals↗
PubMedDate not supplied

Heat treatment of hepatocellular carcinoma cells: increased levels of heat shock proteins 70 and 90 correlate with cellular necrosis.

Immunotherapy, i.e. stimulation of the body's immune response against tumor cells, is a promising approach in cancer treatment. In this context, heat shock proteins (HSP) have been shown to function in tumor antigen chaperoning. HSP are evolutionarily conserved and show increased expression in response to chemical and physical stress. Two members of the HSP family, HSP 70 and 90, seem to further act as immunostimulating agents because of their possible involvement in tumor antigen presentation. We cultured the human hepatocellular carcinoma cell line HepG2 and investigated its HSP content under normal and hyperthermic conditions. Flow cytometry showed increased levels of HSP 70 and 90 after heat shock at 41.8 degrees C for 60 minutes, measured after a subsequent incubation time of five hours, as compared to untreated cells in vitro. We further observed a clear correlation between the HSP 70 and 90 levels and the necrotic cell subpopulation in heat shocked tumor cells. We conclude that HSP expression in HepG2 cells can be enhanced by heat shock treatment in vitro. We suggest that this mechanism can be exploited in increasing tumor immunogenicity.

Antibodies, Monoclonal↗
PubMed1995

Calorimetric determination of the heat of precipitation of pseudoephedrine racemic compound--its agreement with the heat of solution.

The heat of precipitation of dl-pseudoephedrine was determined by direct calorimetry using a Tronac isoperibolic calorimeter. The precipitation of dl-pseudoephedrine was induced by mixing aqueous solutions of the two enantiomers, namely, d- and l-pseudoephedrine, directly in the calorimeter. The molar heat of precipitation of dl-pseudoephedrine was -2.7 and -3.0 kcal/mol at 25 and 30 degrees C, respectively. The aqueous solubility of dl-pseudoephedrine was determined over a temperature range of 20-40 degrees C. The van't Hoff solubility plot was nonlinear. The apparent heat of solution at saturation was obtained from the solubility data using a nonlinear regression model. A good agreement between the magnitude of the apparent heat of solution at saturation and the heat of precipitation was noticed at both 25 and 30 degrees C.

Calorimetry, Differential Scanning↗
PubMed2006

At-column heating and a resistively heated, liquid-cooled thermal modulator for a low-resource bench-top GC x GC.

A transportable GC x GC instrument is under development for on-site applications that would benefit from the enhanced resolution and powers of detection, which can be achieved by this method. In the present study, a low-resource GC x GC instrument using an electrically heated and liquid-cooled single-stage thermal modulator that requires no cryogenic materials is evaluated. The instrument also uses at-column heating, thus eliminating the need for a convection oven to house the two columns. The stainless-steel modulator tube is coated with PDMS, which can be heated to 350 degrees C for sample injection into the second-dimension column. The modulator is cooled to -30 degrees C by a 100 mL/min flow of PEG by means of a commercial liquid chiller and a small recirculating pump. Resistive heating of the modulator tube is provided by a programmable power supply, which uses a voltage program that results in increasing modulator temperature during an analysis. This, together with more rapid cooling by the use of a liquid cooling medium, results in reduced solute breakthrough following each heating cycle as the modulator cools to a temperature where quantitative trapping resumes. As a result, modulated peak widths at half-height of less than 40 ms are observed. Design and performance details are presented along with chromatograms of gasoline and an essential oil sample.

Journal Article↗
PubMed2002

Heat evolution of micelle formation, dependence of enthalpy, and heat capacity on the surfactant chain length and head group.

Micelle formation by many surfactants is endothermic at low temperatures but exothermic at high temperatures. In this respect, dissociation of micelles (demicellization) is similar to dissolving hydrocarbons in water. However, a remarkable difference between the two processes is that dissolving hydrocarbons is isocaloric at about 25 degrees C, almost independently of the hydrocarbon chain length, whereas the temperature (T*) at which demicellization of different surfactants is athermal varies over a relatively large range. We have investigated the temperature dependence of the heat of demicellization of three alkylglucosides with hydrocarbon chains of 7, 8, and 9 carbon atoms. At about 25 degrees C, the heat of demicellization of the three studied alkylglucosides varied within a relatively small range (DeltaH=-7.8+/-0.4 kJ/mol). The temperature dependence of DeltaH(demic) indicates that within the studied temperature range the heat capacity of demicellization (DeltaC(P,demic)) is about constant. The value of DeltaC(P,demic) exhibited an apparently linear dependence on the surfactant's chain length (DeltaC(P,demic)/n(CH(2))=47+/-7 kJ/mol K). Our interpretation of these results is that (i) the transfer of the head groups from micelles to water is exothermic and (ii) the temperature dependence of the heat associated with water-hydrocarbon interactions is only slightly affected by the head group. This implies that the deviation of the value of T* from 25 degrees C results from the contribution of the polar head to the overall heat of demicellization. Calorimetric studies of other series of amphiphiles will have to be conducted to test whether the latter conclusion is general.

Hot Temperature↗