Whole body hyperthermia of rats decreases insulin binding to erythrocytes

125I-insulin binding to rat erythrocytes was studied to investigate the effect of whole body hyperthermia on the insulin receptor. Heat treatment of rats at 42 degrees C for 15 min caused a significant decrease (48.7% of control) in 125I-insulin binding to rat erythrocytes. Scatchard analysis showed that the decreased binding resulted from a decrease in the number of the insulin receptors rather than from a decrease in receptor affinity. The decreased receptor number for insulin showed no evidence of recovery, 2 h and 8 h after the hyperthermia. Plasma insulin levels remained lower than the control, up to 8 h after the hyperthermia, whereas plasma glucose, which decreased immediately after the hyperthermia, increased higher than the control, 8 h after the hyperthermia. The low plasma insulin level and decreased number of insulin receptor are believed to be possible factors for the elevation of plasma glucose.     

The combined action of gamma irradiation and hyperthermia on the structure of the cell population in the Chinese hamster]

A change in the structure of FAF-28 Chinese hamster cell population occurred during 24 h following gamma-irradiation or hyperthermia heating, or the effect of both factors was studied by flow cytofluorometry. With radiation delivered immediately after heating the distribution of cells among cycle phases was nearly the same as with hyperthermia alone: the share of cells at the S-phase was invariable during the first 4-6 h, then it slowly diminished; at G1 it slowly decreased and at G2 increased. When irradiation preceded heating the pattern of cell redistribution during the first hours was the same as that with radiation alone: the "wave" of transition from G1 to S phase was the same, but shorter in amplitude and longer in time; then cells were accumulated at G2+M and remained there for 24 h. Thus, of the two factors applied, the first was the major one in changing the cell population structure during the first hours after treatment. In 24 h the result was the same, that is, the considerable accumulation of cells at G2+M.     

X-ray-induced breaks in the X chromosomes in Drosophila lines of various radiosensitivities

The frequency of X-ray induced X-chromosome breaks has been studied in females of the line rad (2) 201G1 hypersensitive to radiation and in females of the control line selected from the same population. The frequency of X-chromosome breaks was judged based on the frequency of X0 males occurrence. Synergism of the effects of X-rays (at doses 0.1, 0.5 and 1.0 kr) and of hyperthermia (+37 degrees C, 5.5 hours) applied after irradiation served as an indirect evidence for the functioning of DNA repair systems. It is demonstrated that radiosensitivity of mature oocytes of the lines compared was equal and that hyperthermia applied after irradiation increased the latter effect in both lines. Young oocytes of the control line were radioresistant, and hyperthermia applied after irradiation enhanced its effect. Opposite to them, young oocytes of the rad line females were radiosensitive. They did not differ from mature oocytes in the frequency of X-chromosome losses. Synergism of the two factors (irradiation and hyperthermia) was not registered in young oocytes. On the basis of the results obtained, it may be concluded that radiosensitivity of young oocytes in the hypersensitive line is conditioned by the failure of DNA repair systems and that the rad (2) 201G1 gene may be considered, in relation to the genes controlling DNA repair, as a suppressor functioning selectively at a certain stage of oogenesis.     

Assessment of the joint effect of thermal stress,pollution, and parasitic infestation on the activity of antioxidative enzymes in pulmonate mollusk <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis>

This study makes a multifactor analysis of the joint effect of reservoir contamination, parasitic infestation, and experimental hyperthermia on the activity of antioxidative enzymes (peroxidase, catalase, and glutathione S-transferase) in the pulmonate mollusk Lymnaea stagnalis from the clean Naroch Lake and contaminated Chizhovsky Reservoir in the Republic of Belarus. The activity of peroxidase is ascertained to be affected most strongly by the simultaneous effect of parasitic infestation and reservoir contamination and parasitic infestation coupled with experimental hyperthermia. The joint effect of parasitic infestation and reservoir pollution is found to influence the activity of catalase. Meanwhile, no correlation is found between the studied factors and the activity of glutathione S-transferase. It is shown that there is no mutual influence of the three studied factors on the activity of the investigated enzymes.     

Modulation of temperature-induced tone by vasoconstrictor agents.

One of the primary cardiovascular adjustments to hyperthermia is a sympathetically mediated increase in vascular resistance in the viscera. Nonneural factors such as a change in vascular tone or reactivity may also contribute to this response. Therefore, the aim of this study was to determine whether vascular smooth muscle tone is altered during heating to physiologically relevant temperatures >37 degrees C. Gradually increasing bath temperature from 37 degrees C (normothermia) to 43 degrees C (severe hyperthermia) produced graded contractions in vascular ring segments from rat mesenteric arteries and thoracic aortae. In untreated rings these contractions were relatively small, whereas hyperthermia elicited near-maximal increases in tension when rings were constricted with phenylephrine or KCl before heating. In phenylephrine-treated mesenteric arterial rings, the contractile responses to heating were markedly attenuated by the Ca2+ channel antagonists nifedipine and diltiazem. Diltiazem also blocked the contractile responses to heating in thoracic aortic rings. These results demonstrate that hyperthermia has a limited effect on tension generation in rat vascular smooth muscle in the absence of vascular tone. However, in the presence of agonist-induced tone, tension generation during heating is markedly enhanced and dependent on extracellular Ca2+. In conclusion, these data suggest that local regulation of vascular tone can contribute to the hemodynamic adjustments to hyperthermia.     

Growth factors and hyperthermia. II. Viability of Chinese hamster ovary HA-1 cells during serum starvation and hyperthermia

We tested the possibility that hyperthermia kills HA-1 cells in a manner analogous to growth factor deprivation. HA-1 cells were inactivated by serum starvation when incubated in Eagle's MEM at a density of 40 cells/cm2 or less. Cells became resistant to the absence of serum when the cell density was greater than 400 cells/cm2 or when lethally irradiated HA-1 feeder cells were present. The feeder cells exerted their effect through a diffusible factor. In addition, a 1:1 mixture of Eagle's MEM and Ham's F-12 enabled HA-1 cells to remain viable without serum. Ten days growth in Eagle's MEM + Ham's F-12 without serum resulted in the formation of microcolonies of cells. This indicated that growth factor deprivation was not lethal to HA-1 cells, and it suggested that they may have been partially transformed. The presence of the growth factors insulin, transferrin, and fibroblast growth factor (FGF) reduced cell killing by a small amount during conditions of serum starvation. After hyperthermia, the presence of growth factors again diminished cell killing by a modest amount (approximately twofold). Feeder cells also improved cell survival after hyperthermia. The effect of feeder cells was greatest when cells were trypsinized immediately after hyperthermia. When cells were not trypsinized after heating, feeder cells increased survival less than twofold. In summary, the absence of growth factors was not lethal to HA-1 cells, and therefore the cytotoxic effects of hyperthermia could not be explained fully by the failure to bind growth factors. HA-1 feeder cells secreted undefined, growth-promoting substances, but feeder cells exerted only a small positive effect on cell survival after hyperthermia when cells were not trypsinized after heating.     

The action of urocortins on body temperature in rats

The actions of individual urocortins on colon temperature were studied in rats. Urocortin 1, urocortin 2 or urocortin 3 was injected into the lateral brain ventricle in conscious rats and the colon temperature was measured at different times following injection, for up to 6 h. In order to study the possible role of prostaglandins, the animals were treated with either a urocortin together with the pyrazolone derivative noraminophenazone to inhibit the action of cyclooxygenase in initiating hyperthermia, or with noraminophenazone 30 min following urocortin administration to act on existing hyperthermia. Noraminophenazone was administered intramuscularly in a dose of 50 mg/kg. Urocortin 1 caused a dose-related increase in colon temperature, maximal action being observed at a dose of 2 microg with the maximal increase in body temperature at 4 h. Noraminophenazone prevented the urocortin-induced increase in colon temperature and attenuated the already existing elevated body temperature. Somewhat similar action was observed with urocortin 2. However, following treatment with 0.5 or 1.0 microg urocortin 2, the action was already over at 2 h, whereas 2 microg increased the colon temperature steadily, with a maximum at 4 h. Noraminophenazone blocked or diminished the action of urocortin 2. Urocortin 3 in a dose of 1 microg was the most effective in increasing the colon temperature; the maximal effect was observed at 2 h. Noraminophenazone blocked the development of urocortin 3-induced hyperthermia, or attenuated it when the hyperthermia was already present. The results demonstrated that urocortin 1, 2 or 3 caused increases in body temperature when injected into the lateral brain ventricle, though the optimal dose and the duration of hyperthermia differed for the individual urocortins. The cyclooxygenase inhibitor blocked or diminished the action of these urocortins, indicating the involvement of prostaglandins in urocortin-induced hyperthermia.     

Hyperthermic potentiation of chromosome aberrations by anticancer antibiotics

In view of the success of hyperthermia as a modality in cancer treatment, we have studied its effect on chromosomes in combination with anticancer antibiotics. Three classes of chemicals, one with a non-delayed type of effect (adriamycin), one with a delayed type of effect (mitomycin C), and one with a truely radio-mimetic effect (bleomycin) were selected for study on human lymphocytes and Chinese hamster K-1 cells. Propane sultone was also included because its effect on plants is suppressed by hyperthermia. The data show increased because its effect on plants is suppressed by hyperthermia. The data show increased potential of these chemicals to induce chromosome aberrations when applied at temperatures higher than 37 degrees C, irrespective of the phase of cell cycle. The potentiation may be due to true synergism (bleomycin) of facilitation of entry of larger quantities of the drug (adriamycin). No potentiating effect was observed on the induction of sister chromatid exchanges (SCEs).     

Death receptors mediate the adverse effects of febrile-range hyperthermia on the outcome of lipopolysaccharide-induced lung injury

We have shown that febrile-range hyperthermia enhances lung injury and mortality in mice exposed to inhaled LPS and is associated with increased TNF-α receptor activity, suppression of NF-κB activity in vitro, and increased apoptosis of alveolar epithelial cells in vivo. We hypothesized that hyperthermia enhances lung injury and mortality in vivo by a mechanism dependent on TNF receptor signaling. To test this, we exposed mice lacking the TNF-receptor family members TNFR1/R2 or Fas (TNFR1/R2(-/-) and lpr) to inhaled LPS with or without febrile-range hyperthermia. For comparison, we studied mice lacking IL-1 receptor activity (IL-1R(-/-)) to determine the role of inflammation on the effect of hyperthermia in vivo. TNFR1/R2(-/-) and lpr mice were protected from augmented alveolar permeability and mortality associated with hyperthermia, whereas IL-1R(-/-) mice were susceptible to augmented alveolar permeability but protected from mortality associated with hyperthermia. Hyperthermia decreased pulmonary concentrations of TNF-α and keratinocyte-derived chemokine after LPS in C57BL/6 mice and did not affect pulmonary inflammation but enhanced circulating markers of oxidative injury and nitric oxide metabolites. The data suggest that hyperthermia enhances lung injury by a mechanism that requires death receptor activity and is not directly associated with changes in inflammation mediated by hyperthermia. In addition, hyperthermia appears to enhance mortality by generating a systemic inflammatory response and not by a mechanism directly associated with respiratory failure. Finally, we observed that exposure to febrile-range hyperthermia converts a modest, survivable model of lung injury into a fatal syndrome associated with oxidative and nitrosative stress, similar to the systemic inflammatory response syndrome.     

热疗联合一氧化氮供体硝酸异山梨酯诱导Hep-A细胞凋亡的研究

To investigate the apoptosis of Hep-A cells induced by hyperthermia combined with Nitric Oxide donor (Isosorbide dinitrate, ISDN) and its mechanism. The inhibitory effect on the growth of Hep-A cells was measured by MTT assay. Apoptosis of Hep-A cells was observed by electron microscopy and flow cytometry. The levels of Bcl-2 were detected with Western blot assay. It showed stronger antiproliferative ability in three experimental groups than that in control, and hyperthermia combined with ISDN group had better inhibitory effect than other groups (p < 0.05). With electron microscopy, marked changes of cell apoptosis were observed, including microvilli disappearance or reduction, cell shrinkage, chromatin condensation or margination and the presence of "apoptosis bodies". The apoptotic ratio induced by hyperthermia and ISDN group was higher than other groups, furthermore, the levels of Bcl-2 were decreased in three experimental groups. The present study indicated that hyperthermia combined with ISDN could induce apoptosis of Hep-A cells and be more effective than either hyperthermia or ISDN, which may be related to expression decreased Bcl-2.     

Effects of halothane, caffeine, dantrolene and tetracaine on the calcium permeability of skeletal sarcoplasmic reticulum of malignant hyperthermic pigs

Preparing skeletal sarcoplasmic reticulum from both normal and malignant hyperthermia susceptible pigs, the effects of various drugs on the passive calcium permeability of these sarcoplasmic reticulum preparations were studied. It was found that, in the absence of halothane, the permeability of heavy sarcoplasmic reticulum prepared from malignant hyperthermia susceptible pigs was much higher than that of normal pigs. It was observed that halothane, at concentrations above 10 microM (well below anesthetic concentrations, which are on the order of 1 mM), increased the permeability of sarcoplasmic reticulum. The Hill coefficient of the effect of halothane ranged from 1.96 to 2.25, suggesting that some kind of cooperativity was involved in this reaction. The effects of caffeine were similar to those of halothane. Inhibitors, such as tetracaine and ruthenium red inhibited both the calcium permeability and the halothane-induced increment. The Hill coefficient of the effect of tetracaine was 1.75. The mode of inhibition suggests that tetracaine directly binds with the calcium channel to inhibit the calcium efflux. On the contrary, dantrolene did not affect the calcium permeability of the sarcoplasmic reticulum. However, it inhibited the halothane-induced and caffeine-induced increments of the permeability. The Hill coefficient of inhibition by dantrolene ranged from 2.3 to 3.9, suggesting that several molecules of dantrolene may interact cooperatively with one calcium release channel to inhibit the effect of halothane. These results suggest that dantrolene has a unique inhibitory action, which may be related to its efficacy in ameliorating the syndrome of malignant hyperthermia.     

Effect of hyperthermia on epididymal cyclic AMP levels in diabetic non-diabetic and hypophysectomized rats.

The effect of elevated body temperatures on the concentrations of epididymal cyclic AMP levels in non-diabetic, diabetic and hypophysectomized rats was studied. Cyclic AMP levels were increased during hyperthermia in all animals examined. This increase in epididymal cyclic AMP concentration was not seen in animals that had been supplemented with exogenous insulin prior to the experiment. The effect of pituitary lipolytic hormones on epididymal cyclic AMP levels was also investigated. Significant elevations of epididymal cyclic AMP levels were observed in hypophysectomized rats during hyperthermia indicating that pituitary hormones are not essential in causing these increases. Extrapituitary hormones, such as glucagon, might be responsible for epididymal cyclic AMP increases. Increases in epididymal cyclic AMP levels may therefore be the result of the reduction of blood insulin and concomitant increases of lipolytic hormones of both pituitary and extrapituitary origins.     

Effects of hyperthermia and nicotinamide on DNA repair synthesis, ADP-ribosyl transferase activity, NAD+ and ATP pools, and cytotoxicity in gamma-irradiated human mononuclear leukocytes

Effects of hyperthermia and nicotinamide on ADP-ribosyl transferase activity (ADPRT), unscheduled DNA synthesis (UDS), NAD+- and ATP-pools and cytotoxicity were investigated in gamma-irradiated human mononuclear leukocytes. A significant decrease in radiation-induced UDS after heat treatment for 45 min was found. Nicotinamide increased the UDS levels in irradiated cells, but no effect of hyperthermia on these increased UDS values was observed. In the presence of 2 mM nicotinamide radiation-induced ADPRT activity was reduced to about 50 per cent. However, hyperthermia for 45 min was found to have no effect on the enzyme activity for temperatures below 46 degrees C. Nicotinamide increased the NAD+ pool in unirradiated cells. Damaging the cells with gamma-radiation leads to a severe depletion of the NAD+ pool. The NAD+ pool is restored, however, if the cells repair for 5 h at 37 degrees C. When radiation-damaged cells were treated with hyperthermia, exogenously supplied nicotinamide could not be converted to NAD+ in sufficient amounts to prevent NAD+ depletion. These data indicate that the radiosensitizing effect of heat and nicotinamide could both be explained by effects on the enzyme ADPRT, i.e. nicotinamide by directly blocking the enzyme and hyperthermia by limiting the co-substrate (NAD+).     

Effect of hyperthermia on the antitumor actions of interferons.

Hyperthermia treatment has been shown to enhance the in vitro antiproliferative effects of IFN-alpha, IFN-beta, and IFN-gamma, with IFN-gamma being more strongly enhanced than IFN-alpha. The comparative effects of hyperthermia on the in vivo antitumor activities of IFN-alpha and IFN-gamma were evaluated in the murine system using both subcutaneous and intraperitoneal B16 melanoma tumor model systems. Heat-induced whole body hyperthermia, resulting in a 2 degree C rise in body temperature, was administered by incubating the mice for 8 hours in a dry incubator at 37.1 degrees C. Whole body hyperthermia was found to enhance the antitumor activity of IFN-alpha by approximately 1.0 fold and 1.2 fold for the subcutaneous and intraperitoneal tumor models, respectively. This represented an additive effect of hyperthermia and IFN-alpha. Hyperthermia was found to enhance the antitumor activity of IFN-gamma by approximately 2.9 fold and 2.2 fold for the subcutaneous and intraperitoneal tumor models, respectively. This represented a synergistic effect of hyperthermia and IFN-gamma. The results of this in vivo study confirm and extend the in vitro observation that hyperthermia more strongly enhances the antitumor action of IFN-gamma than IFN-alpha. These results may have clinical importance because they suggest that hyperthermia may be used in combination with IFN-gamma to provide a synergistically enhanced antitumor action.     

Lipid peroxide levels in a murine adenocarcinoma exposed to hyperthermia: the role of glutathione depletion.

Increased lipid peroxide levels were obtained 1 h after a 60-min 43 degrees C hyperthermia treatment of a solid murine C3H mammary adenocarcinoma, grown subcutaneously in the hind paws of mice. Previous work from our group revealed that this heat treatment depletes the intracellular glutathione (GSH) content in this tumor. To investigate GSH depletion as one tentative mechanism behind the increased lipid peroxide levels obtained, we also measured the formation of lipid peroxidation products after extensive DL-buthionine-S,R-sulfoximine (BSO)-induced GSH depletion. The lipid peroxide effect provoked by BSO was less than that of the 60-min hyperthermia treatment. We therefore propose that the increased lipid peroxide levels induced by heat treatment do not correlate primarily with the observed decrease in GSH levels. Furthermore, in thermotolerance-induced tumors, lipid peroxide levels after a second heat treatment were observed to increase concomitantly with the cessation of thermotolerance. Lipid peroxide levels were also studied in liver, lung, and heart. Following BSO treatments, and up to 2-fold increase was observed in these organs in non-tumor-bearing mice. It was also observed that the intrinsic lipid peroxide levels in these organs from tumor-bearing mice were approximately 1.5- to 4-fold higher in comparison with non-tumor-bearing mice, thus indicating a systemic effect of the tumor implant.     

Combinatorial effects of radiofrequency hyperthermia and radiotherapy in the presence of magneto-plasmonic nanoparticles on MCF-7 breast cancer cells

Here, the effects of combinatorial cancer therapy including radiotherapy (RT) and radiofrequency (RF) hyperthermia in the presence of gold-coated iron oxide nanoparticles (Au@IONPs), as a thermo-radio-sensitizer, are reported. The level of cell death and the ratio of Bax/Bcl2 genes, involved in the pathway of apoptosis, were measured to evaluate the synergistic effect of Au@IONPs-mediated RF hyperthermia and RT. MCF-7 human breast adenocarcinoma cells were treated with different concentrations of Au@IONPs. After incubation with NPs, the cells were exposed to RF waves (13.56 MHz; 100 W; 15 min). At the same time, thermometry was performed with an infrared (IR) camera. Then, the cells were exposed to 6 MV X-ray at various doses of 2 and 4 Gy. MTT (3-[4,5-dimethylthiazol-2-y1]-2,5-diphenyltetrazolium bromide) assay was performed to evaluate cell viability and quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression ratio of Bax/Bcl2. Cellular uptake of nanoparticles was confirmed qualitatively and quantitatively. The results obtained from MTT assay and qRT-PCR studies showed that NPs and RF hyperthermia had no significant effect when applied separately, while their combination had synergistic effects on cell viability percentage and the level of apoptosis induction. A synergistic effect was also observed when the cancer cells were treated with a combination of NPs, RF hyperthermia, and RT. On the basis of the obtained results, it may be concluded that the use of magneto-plasmonic NPs in the process of hyperthermia and RT of cancer holds a great promise to develop a new combinatorial cancer therapy strategy.     

Effect of radio wave-induced hyperthermia on microflora of the prostate in the treatment of prostatitis associated with infertility

The influence of hyperthermia induced by radiowaves on the microflora of the prostate in cases of male sterility was studied. The use of hyperthermia was shown to produce a stable decrease in bacteriospermia and the persistence potential of bacteria isolated from sperm. Hyperthermia produced a bactericidal effect not only on microorganisms contained in sperm but also on the microflora of prostatic tissues 1 cm deep. The study gave grounds for treating male sterility with the use of hyperthermia induced by radiowaves and a subsequent course of antibiotics to achieve the stable decrease of bacteriospermia and the restoration of the reproductive function.     

Effect of a combination of mild-temperature hyperthermia and nicotinamide on the radiation response of experimental tumors

Ogawa, A., Griffin, R. J. and Song, C. W. Effect of a Combination of Mild-Temperature Hyperthermia and Nicotinamide on the Radiation Response of Experimental Tumors. The effect of mild-temperature hyperthermia and nicotinamide individually or combined on tumor radiosensitivity was investigated with SCK tumors grown s.c. in the right hind limbs of A/J mice. An i.p. injection of nicotinamide at 50-250 mg/kg slightly enhanced the cell killing caused by 10-20 Gy of ionizing radiation as determined by the in vivo/in vitro tumor excision assay. Treatment of tumors with mild-temperature hyperthermia at 41.5 degrees C for 60 min prior to tumor irradiation was significantly more effective than nicotinamide and the combination of nicotinamide and hyperthermia was far more effective than nicotinamide or hyperthermia alone in enhancing radiation-induced cell killing. Radiation-induced tumor growth delay was enhanced by a factor of 1.2 by 50 mg/kg nicotinamide, 2.1 by hyperthermia, and 3.6 by the combination of nicotinamide and hyperthermia. Taking these results and those of our previous studies together, we conclude that mild-temperature hyperthermia increases tumor blood flow and oxygenation and that combining mild-temperature hyperthermia and nicotinamide is more effective than either of these alone in increasing tumor radiosensitivity.     

The influence of nitric oxide inductor (NaNO2) on the sensitivity of Chinese hamster cells to hyperthermia

Formerly we reported the reduction of sensitivity to gamma- and UV-radiation in Chinese hamster cells of line 90 under the influence of nitric oxide inductor (NaNO2). Of interest was to learn if it possible to reduce the influence of hyperthermia on cells by means of NO inductor. A 1 h long incubation with this NO donor demonstrated an increased survival of cells heated up to 45 degrees C, and a decreased frequency of chromosomal aberrations in these. Employment of cycloheximide (CHE), an inhibitor of protein synthesis, and administration of CHE together with nitric oxide donor (NaNO2), equally increased the cell survival at hyperthermia. These and relevant literature data suggest that the demonstrated effect of exogenous NO may be associated with HSP70 protein. The noticed decrease in the number of chromosomal aberrations in heated cells under the influence of NO donor may play an important role in its modifying effect on cells at hyperthermia.     

Dependence of synergism of the combined effect of ultrasound and hyperthermia upon intensity of ultrasound

The inactivation of wild-type yeast Saccharomyces cerevisiae was studied after simultaneous treatment with ultrasound and hyperthermia. A temperature range was established within which ultrasound and hyperthermia exert a synergistic action. The effect was shown to depend on ultrasound intensity and the temperature at which the treatment takes place. The temperature range enhancing the ultrasound effect shifted forward higher temperature with increasing ultrasound intensity. For every intensity value, an optimal temperature exists at which the synergetic effect is maximum. The biophysical interpretation of the results obtained is based on the assumption that synergism is due to an additional lethal damage, which arises from the interaction of some sub-lesions induced by both agents. These sublesions are considered non-lethal if the agents are applied separately.