Chronic Hyperthermia Research Articles

Effects of Heat Therapy on Prostate Cancer Cells Subjected to 4 Gy Radiation

Background Despite many advancements in treatment options, radiation therapy remains a common treatment for individuals diagnosed with prostate cancer. However, radiation resistance presents a significant challenge for many patients. Due to its numerous effects on cancer cell growth and survival, heat therapy has been studied as a potential mechanism to improve radiation efficacy. However, the modality of heat therapy varies widely between studies, and the majority of heat therapy research relies on non-physiological temperatures (>43º C). We hypothesized that mild temperature hyperthermia would improve the efficacy of radiation of prostate cancer cells in vitro. Methods Clonogenic survival was assessed using human prostate cancer (PC-3) cells in vitro. Cells were grown in tissue culture flasks maintained in a 37º C incubator with 5% CO2 and randomized into 3 groups: normothermic (NT; n=8), acute hyperthermia (HTA; n=8), and chronic hyperthermia (HTC; n=8). NT cells were maintained in a normal incubator until radiation. For heat treatments, HTA cells were heated to 41.0º C in a separate incubator for 1 h immediately prior to radiation. HTC cells were heated to 41.0º C in a separate incubator for 1 h each session, for a total of 3 heat treatments, each separated by 48 h, with the final heat treatment occurring 24 h prior to radiation. Immediately following a single dose of 4 Gy radiation, each group of cells were counted and plated into 60 mm culture dishes at densities of both 500 cells/plate and 1000 cells/plate, with 5 replicates plated per density. Following 8 days of incubation, cells were fixed and stained and colonies of greater than 50 cells were counted. Results The survival fractions were determined from the average of the two plating densities. Clonogenic cell survival was significantly reduced in HTA vs. NT (11.6% ± 2% vs. 19.3% ± 1%, p<0.05) and in HTC vs. NT (8.3% ± 2% vs. 19.3% ± 1%, p<0.05). Cell survival between HTA and HTC was not different (p>0.05). Conclusions These results suggest that both acute and chronic mild hyperthermia improve the efficacy of 4 Gy radiation in PC-3 cells. While exact mechanisms are yet to be elucidated, it is thought that hyperthermia at lower temperature induces DNA damage, inhibits DNA damage repair, or alters cell cycle progression, which individually or in combination with one another, may potentiate the effects of radiation. Mild temperature hyperthermia prior to radiation may be an effective neo-adjuvant to increase the radiosensitivity of prostate cancer cells.

Морфологическая характеристика щитовидной железы половозрелых крыс при воспроизведении хронической гипертермии средней степени и введении инозина

Морфологическая характеристика щитовидной железы половозрелых крыс при воспроизведении хронической гипертермии средней степени и введении инозина

The Impact of Pre-Cooling and CoQ10 Supplementation on Mediators of Inflammatory Cytokines in Elite Swimmers

Chronic intensive exercise and hyperthermia may cause immune system function disturbance. We aimed to investigate the effect of 14-day coenzyme Q10 (CoQ10) supplementation and pre-cooling strategy on serum changes of inflammatory cytokines [interleukin-10 (IL-10), interleukin-8 (IL-8), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)], and high-sensitivity C-reactive protein (hs-CRP), myeloperoxidase (MPO) and xanthine oxidase (XO) enzymes, leukocyte counts (WBC), and stress hormones (catecholamine and cortisol) responses in elite swimmers during competition phase. Thirty-six healthy males were randomly selected and divided into four groups of CoQ10, precooling, supplementation with precooling, and control. Blood sampling was done pre and post (before and after acute recoding bout) administration of CoQ10 and pre-cooling. There was no significant statistical difference among groups for the indices levels of IL-10, IL-8, IL-6, TNF-α, hs-CRP, catecholamine, cortisol, MPO, XO, and WBC counts at the pre sampling (P > 0.05). While, pre-cooling and control groups show a significant increase indices levels compared to the supplementation and supplementation with precooling groups in the post-sampling (two stages), (P ˂ 0.05). Short-term oral CoQ10 supplementation prevents adverse changes mediators of inflammatory cytokines following heavy swimming trainings and acute recording bout. In addition, pre-cooling strategy individually has no desired effect on the mediators of inflammatory cytokines.

COMPARATIVE HISTOPATHOLOGICAL CHANGES OF LIVER, KIDNEY AND APPENDIX OF RABBITS TREATED WITH INORGANIC NANO CHROMIUM TO AMELIORATE HEAT STRESS EFFECT

The objective of the current experiment was to describe the effects of nano-chromium chloride (CrCl3) on chronic hyperthermia (32.8 ± 1.5 °C) on rabbit liver, kidney, and appendix in comparison with rabbits at room temperature (24.5 ± 1.3 °C) and treated with the same concentration of nano-chromium chloride. For this study, 108 rabbits of two different breeds (New Zealand White and Rex) were used and randomly allocated into 12 groups. The study was conducted as a completely randomized 2 × 2 × 3 factorial (n = 9) design. Treatments were temperature, breed, and concentration of nano-chromium chloride (0, 1, or 2 mg/L) the results showed that heat stress caused granular hepatic vacuolation, severe congestion of the central vein, and sinusoids in the liver. As well as degenerative changes within the epithelial lining of tubules in the kidney and lymphoid depletion in the appendix. The liver tissue of the New Zealand rabbits was affected more by heat stress than Rex Rabbits, but no difference was observed in the kidney or appendix tissues. The addition of 2 mg/L nano-chromium was more effective than 1 mg/L on the heat stressed rabbit tissues, but it caused hepatic vacuolation with glycogen infiltration in liver tissue and mild vacuolation in the renal tubular epithelium.Key words: rabbit; nano-chromium; heat stress; histopathology

Характеристика линейных размеров и объёма щитовидной железы крыс репродуктивного возраста под воздействием на организм хронической гипертермии

Характеристика линейных размеров и объёма щитовидной железы крыс репродуктивного возраста под воздействием на организм хронической гипертермии

Органометрическая характеристика щитовидной железы половозрелых крыс при воздействии на их организм хронической гипертермии средней степени в сочетании с применением инозина

Органометрическая характеристика щитовидной железы половозрелых крыс при воздействии на их организм хронической гипертермии средней степени в сочетании с применением инозина

Differences between the tolerance of camel oocytes and cumulus cells to acute and chronic hyperthermia

The dromedary camel (Camel dromedarius) is physiologically well adapted to life in hot, dry and barren land. In the present study, we report the tolerance of camel oocytes and cumulus cells to acute and chronic heat shock. Camel oocytes and cumulus cells were exposed to acute (45 °C for 2 h) and chronic (45 °C for 20 h) heat shock. Our results demonstrated that acute and chronic heat shock altered malondialdehyde concentration, which is a marker for oxidative stress. Furthermore, the heat shock reduced glutathione levels during in vitro oocyte maturation. The expression of two well-known heat shock proteins HSP70 and HSP90 were increased similarly in oocytes and cumulus cells after acute heat shock. Oocytes were less tolerant to the short acute heat shock, and showed decreased maturation, which leads to reduction in ooplasmic diameter and an increase in chromosomal count abnormalities. Furthermore, the pro-apoptotic genes P53 and BAX had increased expression levels, whereas for the anti-apoptotic gene such as BCL2 expression levels was decreased. On the other hand, the cumulus cells tolerated acute and chronic heat shock, as evident by the increase in HSP70 and HSP90 expression and steady expression levels of P53, BAX, and BCL2 after acute hyperthermia. Cumulus cells regained their vitality and ability to proliferate after chronic hyperthermia and showed wound healing capabilities after 9 days of chronic hyperthermia. Collectively, these results indicate the adaptive tolerance of camel somatic cells to acute and chronic heat shock, which is lethal to cells in many other mammals.

Epidemiology, causes, evolution and outcome in a single-center cohort of 1116 critically ill patients with hypoxic hepatitis

BackgroundHypoxic hepatitis (HH) is a type of acute hepatic injury that is histologically characterized by centrilobular liver cell necrosis and that is caused by insufficient oxygen delivery to the hepatocytes. Typical for HH is the sudden and significant increase of aspartate aminotransferase (AST) in response to cardiac, circulatory or respiratory failure. The aim of this study is to investigate its epidemiology, causes, evolution and outcome.MethodsThe screened population consisted of all adults admitted to the intensive care unit (ICU) at the Ghent University Hospital between January 1, 2007 and September 21, 2015. HH was defined as peak AST > 5 times the upper limit of normal (ULN) after exclusion of other causes of liver injury. Thirty-five variables were retrospectively collected and used in descriptive analysis, time series plots and Kaplan–Meier survival curves with multi-group log-rank tests.ResultsHH was observed in 4.0% of the ICU admissions at our center. The study cohort comprised 1116 patients. Causes of HH were cardiac failure (49.1%), septic shock (29.8%), hypovolemic shock (9.4%), acute respiratory failure (6.4%), acute on chronic respiratory failure (3.3%), pulmonary embolism (1.4%) and hyperthermia (0.5%). The 28-day mortality associated with HH was 45.0%. Mortality rates differed significantly (P = 0.007) among the causes, ranging from 33.3% in the hyperthermia subgroup to 52.9 and 56.2% in the septic shock and pulmonary embolism subgroups, respectively. The magnitude of AST increase was also significantly correlated (P < 0.001) with mortality: 33.2, 44.4 and 55.4% for peak AST 5–10× ULN, 10–20× ULN and > 20× ULN, respectively.ConclusionThis study surpasses by far the largest cohort of critically ill patients with HH. HH is more common than previously thought with an ICU incidence of 4.0%, and it is associated with a high all-cause mortality of 45.0% at 28 days. The main causes of HH are cardiac failure and septic shock, which include more than 3/4 of all episodes. Clinicians should search actively for any underlying hemodynamic or respiratory instability even in patients with moderately increased AST levels.

Limits to sustained energy intake XXIV: impact of suckling behaviour on the body temperatures of lactating female mice.

The objective of this study was to investigate the potential causes of high body temperature (Tb) during lactation in mice as a putative limit on energy intake. In particular we explored whether or not offspring contributed to heat retention in mothers while suckling. Tb and physical activity were monitored in 26 female MF1 mice using intraperitoneally implanted transmitters. In addition, maternal behaviour was scored each minute for 8 h d−1 throughout lactation. Mothers that raised larger litters tended to have higher Tb while nursing inside nests (P < 0.05), suggesting that nursing offspring may have influenced heat retention. However, Tb during nursing was not higher than that recorded during other behaviours. In addition, the highest Tb during the observation period was not measured during nursing behaviour. Finally, there was no indication that mothers discontinued suckling because of a progressive rise in their Tb while suckling. Tb throughout lactation was correlated with daily increases in energy intake. Chronic hyperthermia during lactation was not caused by increased heat retention due to surrounding offspring. Other factors, like metabolic heat produced as a by-product of milk production or energy intake may be more important factors. Heat dissipation limits are probably not a phenomenon restricted to lactation.

Neonatal capsaicin treatment in rats induces chronic hyperthermia resulting in infectious disease.

Treatment of neonatal animals with capsaicin has previously been associated with long-lasting hyperthermia and severe cutaneous lesions. The present study analyzed the effects of capsaicin-induced hyperthermia on the occurrence of infectious disease and pruritic dermatitis in a rat model. Pregnant Sprague-Dawley (SD) rats were obtained 1 week prior to parturition. Pups from each litter were randomly assigned to the following experimental groups: Capsaicin-treated (cap-treated; n=10) or vehicle-treated (n=5). Capsaicin (50 mg/kg) or vehicle were systemically administered to the SD rat pups (age, 48 h), after which body temperature was measured using a biotelemetry system, and the effects of hyperthermia on the ability of the rat pups to resist bacterial infection were analyzed. Furthermore, pruritus-induced scratching behavior and dermatitis were assessed, and changes in interleukin (IL)-4- and IL-13-induced immunoglobulin E expression were measured. Treatment of neonatal rats with capsaicin resulted in chronic hyperthermia, which had negative effects on the host immune defense response. The expression levels of T-helper type 2 cell-associated cytokines were significantly increased (P<0.01) in the cap-treated rats following bacterial infection with Staphylococcus aureus or Streptococcus agalactiae. Furthermore, cap-treated rats exhibited pruritus-induced scratching behavior and dermatitis. The results of the present study suggested that treatment of neonatal rats with capsaicin induces chronic hyperthermia and decreases the effectiveness of the host defense system. Therefore, a cap-treated neonatal rat model may be considered useful when investigating the association between hyperthermia and infectious disease.

Limits to sustained energy intake XX: body temperatures and physical activity of female mice during lactation

Lactating animals consume greater amounts of food than non-reproductive animals, but energy intake appears to be limited in late lactation. The heat dissipation limit theory suggests that the food intake of lactating mice is limited by the capacity of the mother to dissipate heat. Lactating mice should therefore have high body temperatures (Tb), and changes in energy intake during lactation should be reflected by variation in Tb. To investigate these predictions, 26 mice (Mus musculus) were monitored daily throughout lactation for food intake, body mass, litter size and litter mass. After weaning, 21 days postpartum, maternal food intake and body mass were monitored for another 10 days. Maternal activity and Tb were recorded every minute for 23 h a day using implanted transmitters (vital view). Energy intake increased to a plateau in late lactation (days 13-17). Daily gain in pup mass declined during this same period, suggesting a limit on maternal energy intake. Litter size and litter mass were positively related to maternal energy intake and body mass. Activity levels were constantly low, and mice with the largest increase in energy intake at peak lactation had the lowest activity. Tb rose sharply after parturition and the circadian rhythm became compressed within a small range. Tb during the light period increased considerably (1.1 ° C higher than in baseline), and lactating mice faced chronic hyperthermia, despite their activity levels in lactation being approximately halved. Average Tb increased in relation to energy intake as lactation progressed, but there was no relationship between litter size or litter mass and the mean Tb at peak lactation. These data are consistent with the heat dissipation limit theory, which suggests performance in late lactation is constrained by the ability to dissipate body heat.

Repeated social defeat stress induces chronic hyperthermia in rats

Psychological stressors are known to increase core body temperature ( T c) in laboratory animals. Such single stress-induced hyperthermic responses are typically monophasic, as T c returns to baseline within several hours. However, studies on the effects of repeated psychological stress on T c are limited. Therefore, we measured T c changes in male Wistar rats after they were subjected to 4 social defeat periods (each period consisting of 7 daily 1 h stress exposures during the light cycle followed by a stress-free day). We also assessed affective-like behavioral changes by elevated plus maze and forced swim tests. In the stressed rats, the first social defeat experience induced a robust increase in T c (+ 1.3 °C). However, the T c of these rats was not different from control animals during the subsequent dark period. In comparison, after 4 periods of social defeat, stressed rats showed a small but significantly higher (+ 0.2–0.3 °C) T c versus control rats during both light and dark periods. Stressed rats did not show increased anxiety-like behavior versus control rats as assessed by the elevated plus maze test. However, in the forced swim test, the immobility time of stressed rats was significantly longer versus control rats, suggesting an increase in depression-like behavior. Furthermore, hyperthermia and depression-like behavior were still observed 8 days after cessation of the final social defeat session. These results suggest that repeated social defeat stress induces a chronic hyperthermia in rats that is associated with behavior resembling depression but not anxiety.

Character of bones growth in rats under the impact of extreme chronic hyperthermia and its combination with physical activity

Character of bones growth in rats under the impact of extreme chronic hyperthermia and its combination with physical activity

Influence of various chronic hyperthermia modes on a chemical composition of skeleton bones

Influence of various chronic hyperthermia modes on a chemical composition of skeleton bones

Mutational spectrum of conserved regions of TP53 and PTEN genes in Kangri cancer (of the skin) in the Kashmiri population

Kangri cancer is a unique, thermally induced squamous cell carcinoma (SCC) of the skin that develops due to persistent use of a Kangri (a brazier) by the Kashmiri people to combat the cold temperature during winter. Unlike classical UV-induced SCC of the skin, Kangri cancer appears on the legs and abdomen. Its common features are erythematous patches, recurrence and metastasis. In the absence of any molecular etiology, we made a preliminary attempt to estimate the nature and frequency of mutations in the TP53 and PTEN genes in Kangri cancer patients from Kashmir. PCR-SSCP analysis followed by direct sequencing revealed that TP53 mutations account for 40% (12/30) of sporadic Kangri cancer patients and that PTEN mutations account for only 6.6% (2/30). There were 16 mutations in TP53 exons 5 and 7, found in 12 patients. They consisted of 11 substitutions (7 transitions, 3 transversions and 1 double-base) and 5 insertions. The 11 substitutions represent 8 distinct missense mutations, 3 of which were silent mutations. The mutations detected in the PTEN gene consisted of one insertion and one C > T transition. This high percentage of TP53 mutations (especially A > G) showed a statistically significant association with age and positive lymph node status. Our results indicate that TP53 is a predominant target of chronic hyperthermia in the development of Kangri cancer in the moderate risk Kashmiri population. The differences in the TP53 mutation spectrum of UV-induced SCC of the skin and Kangri cancer are probably due to the nature of the respective environmental carcinogens. The study also suggests that TP53 may function as a potential molecular marker and prognostic tool, at least in a subset of sporadic Kangri tumors.

Repeated social defeat stress induces chronic hyperthermia in rats

Repeated social defeat stress induces chronic hyperthermia in rats

The influence of occupational environment and professional factors on the risk of cardiovascular disease

The article reviews the recent scientific literature and the authors' studies on this topic. Occupational conditions and psychological factors have been shown to play an important role in the etiopathogenesis of cardiovascular diseases. Their effect is often indirect, through damage to the central nervous, respiratory, and neuroendocrine systems. Hot climate in the workplace and intense infrared radiation cause the water and electrolyte imbalance and chronic hyperthermia and manifests as neurovegetative dystonia. The long-term effects of low temperatures condition ischemic lesions in circulatory system, trophic organ destruction. The influence of ultrahigh-frequency electromagnetic radiation on the cardiovascular system is directly related to the central nervous system and neurohumoral lesions. "Microwave disease" often manifests as polymorphic dystonia. Exposure to occupational vibration causes "white finger" syndrome or Raynaud's phenomenon together with cerebral vascular lesions. Recent studies have confirmed that noise as a chronic stressor causes the imbalance in the central and vegetative nervous systems and changes in homeostasis. Noise increases catecholamine and cholesterol concentration in blood, has an effect on plasma lipoprotein levels, increases heart rate, arterial blood pressure, and risk of myocardial infarction. Psychophysiological changes caused by long-term stress influence constant pathological changes in the central nervous system, endocrine and cardiovascular systems. The long-term effect of psychogenic stressors is very important in the etiopathogenesis of psychosomatic diseases.

Estimation of the death rate of 3T3 NIH cell at different phases of the cell cycle in chronic hyperthermia within the physiological temperature range.

Estimation of the death rate of 3T3 NIH cell at different phases of the cell cycle in chronic hyperthermia within the physiological temperature range.

Alterations in core body temperature, locomotor activity, and corticosterone following acute and repeated social defeat of male NMRI mice

Repeated social defeat of male NMRI mice, coupled with the stress of continuously living opposite a dominant animal, induces a citalopram-reversible increase in anxiety. The experiments reported in the present paper were performed in an attempt to further validate this paradigm by studying the effects of acute and repeated social defeat on corticosterone and the circadian rhythms of core body temperature and locomotor activity, measured by telemetry. Acute social defeat induced a large (controls: 37.14±0.29°C; subordinates: 39.79±0.33°C) increase in core body temperature and corticosterone (controls: 30.14±2.70 ng/ml; subordinates: 89.62±9.25 ng/ml). Repeated social defeat (24 defeats) induced a chronic elevation in core body temperature across 24-h (controls: 36.62±0.04°C; subordinates: 37.11±0.16°C) in subordinate animals and a very large increase in corticosterone (controls: 28.60±1.27 ng/ml; subordinates: 441.52±8.86 ng/ml). These results illustrate that the chronic social defeat procedure described in this paper induces a state of chronic stress in the subordinate animals. Further studies are warranted to ascertain if the chronic hyperthermia and increases in corticosterone observed in the subordinate animals could be attenuated by chronic antidepressant treatment, thus further extending the predictive validity of this model.

The development and magnitude of thermotolerance during chronic hyperthermia in murine bone marrow granulocyte-macrophage progenitors: I.

Murine bone marrow granulocyte-macrophage progenitors (CFU-GM) are capable of developing thermotolerance during exposure to temperatures < 42.5 degrees C. Bone marrow from the tibia and femora was heated to 40-42 degrees C (i.e. chronic hyperthermia), and challenged immediately with 15 min at 44 degrees C at regular intervals during treatment (step-up heating). CFU-GM were heated and cultured in McCoy's 5A medium + 15% FBS (fetal bovine serum) and lung-conditioned medium (source of colony stimulating factor) in semisolid agar. The kinetics of thermotolerance development and decay, and the magnitude of the thermotolerance during chronic heating with temperatures of 40-41.5 degrees C were similar. Survival increased rapidly to a maxima by approximately 120 min of hyperthermia (temperatures of 40-41.5 degrees C) and thereafter decreased with a slope similar to the controls. Normalization for cell killing by chronic hyperthermia that occurred during "step-up' heating permitted analysis of thermotolerance in the surviving cells. The surviving fraction after 15 min at 44 degrees C, during incubation at 40, 41 and 41.5 degrees C increased from 0.13 to maxima of 0.56 +/- 0.04, 0.71 +/- 0.03 and 0.82 +/- 0.03 respectively, by 150 min and did not decrease for up to 480 min during chronic hyperthermia. The surviving fraction after 15 min at 44 degrees C during incubation at 42 degrees C increased more slowly than during incubations at 40-41.5 degrees C. The survival of thermotolerant cells after exposure to 15 min at 44 degrees C during 42 degrees C chronic hyperthermia was maximal at 0.87 +/- 0.08 by 120 min and then decreased after approximately 150 min of exposure to 42 degrees C. The thermotolerance ratios (TTR's) were 4.0, 5.4, 6.7 and 6.9 for temperatures of 40, 41, 41.5 and 42 degrees C respectively. The results suggest that chronic hyperthermia temperatures (i.e. 40-42 degrees C) induce rapid thermotolerance development in CFU-GM during the thermal exposure and protect this normal marrow progenitor during whole body hyperthermia or ex vivo purging of leukaemic cells.