Interleukin-2 stimulates the colony-forming activity of in vitro irradiated bone marrow

The data are presented on the stimulatory effect of interleukin-2 on the formation of spleen exocolonies from bone marrow irradiated in vitro with doses of 0.5 to 2.5 Gy. It is suggested that the effect observed is associated with the increased proliferation of CFUs survived after irradiation.     

Changes in the concentration of serum fibronectin in irradiated animals

A study of the level of fibronectin in blood serum of Wistar rats at different times after gamma-irradiation (7.5 Gy) has demonstrated a considerable increase in its concentration after 3 days. This increase is a function of radiation dose absorbed (within the range from 1 to 10 Gy). The most pronounced changes are observed with serious and extremely serious forms of acute radiation sickness. The administration of cycloheximide 48 h after irradiation removes completely the increase in the level of blood serum fibronectin.     

A comparative evaluation of the changes in the duration of "hexenal sleep" in acute radiation and combined radiation-thermal lesions]

In experiments with Wistar rats it was found that the increase in the length of the "hexenal dream" during the first week after the effect of a mixture of radiation and heat is much more pronounced than that observed after exposure to radiation alone and independent of the severity of a radiation component (gamma radiation, 4, 6 and 7.5 Gy). The peculiarities revealed in the hypnotic effect of hexenal develop against the background of the postirradiation aggravation of hypoalbuminemia and decrease in the liver ATP.     

Role of interleukin-6 (IL-6) in the pathogenesis of combined radiation/thermal injuries

Combined injury such as whole body gamma-irradiation at the dose of 7 Gy+10% body surface full-thickness thermal burn were investigated in (CBA x C57BL6)F1 mice. Enhanced level of IL-6 in mice serum at 6-24 hs following combined injury was established. The potential inhibiting activity of pentoxifylline (POF) as an influence to IL-6 levels, and measure of several acute phase response signs has been evaluated. It was established, that single POF injection don't modify IL-6 production, don't change leukocytosis and early hyperfermentemia (as alaninaminotransferase levels indicated). But serum albumin content was increased after preliminary POF administration to mice with combined injury. On the other side, mouse anti-IL-6 monoclonal antibodies administration increased 30-days animal survival up to 60% while 100% lethality was registered in untreated mice. Possible anti-inflammatory inactivity reasons of POF under combined injury conditions are discussed in this article, and important role of IL-6 hyperproduction in combined injury outcomes burden is suggested.     

Cytokine production by different population of macrophages following radiation or combined radiation injury

Male mice (CBA x C57BL6)F1 were used for the experiments throughout this study. The levels of spontaneous and LPS-stimulated cytokines production (IL-1 beta, IL-6 and TNF-alpha) by peritoneal, splenic, and bone marrow macrophages were evaluated by means of enzyme-linked immunosorbent assay at 3, 6, 24, 48 and 72 hours after irradiation alone or combined injury (irradiation + thermal burn). The results suggest that macrophages, harvested from the main mice hematopoietic organs (bone marrow, spleen), did not increase cytokines production within the first three days following the 7 Gy gamma-irradiation or combined injury. Peritoneal macrophages revealed a capacity to enhance IL-6 and IL-1 production versus normal healthy mice. There were no significant differences of cytokine-producing activity if macrophages were harvested from irradiated or combined injured mice.     

Some consequences of systemic inflammatory response in the pathogenesis of aggravation of outcomes of combined radiation and thermal injuries

Experiments were executed on (CBA x C57BL6) F1 male mice. Animals were subjected to the total body irradiation with a dose 7 Gy or combine radiation-thermal injury (CRTI), when irradiated animals were additionally subjected to a thermal burn of 10% of the body surface. Some signs of systemic inflammatory response were investigated in these two compared groups. It was established that the period of substantial increasing of the mortality in animals with CRTI (from 7th till 15th day) was characterized with expressed postradiation leikopenia and thrombocytopenia, was accompanied by hypoalbuminemia and hyperfibrinogenemia with a moderate raise in serum ALT activity. From all investigated hematological and biochemical parameters, at CRTI only plasma level of fibrinogen statistically differed from that in a group of the irradiated mice without a burn. It is suggested that endogenous infection and bacterial toxins are important at the pathogenesis of hyperfibrinogenemia and aggravation of CRTI outcomes by the 30-days survival criteria.     

Humanin: A Novel Central Regulator of Peripheral Insulin Action

Background

Decline in insulin action is a metabolic feature of aging and is involved in the development of age-related diseases including Type 2 Diabetes Mellitus (T2DM) and Alzheimer''s disease (AD). A novel mitochondria-associated peptide, Humanin (HN), has a neuroprotective role against AD-related neurotoxicity. Considering the association between insulin resistance and AD, we investigated if HN influences insulin sensitivity.

Methods and Findings

Using state of the art clamp technology, we examined the role of central and peripheral HN on insulin action. Continuous infusion of HN intra-cerebro-ventricularly significantly improved overall insulin sensitivity. The central effects of HN on insulin action were associated with activation of hypothalamic STAT-3 signaling; effects that were negated by co-inhibition of hypothalamic STAT-3. Peripheral intravenous infusions of novel and potent HN derivatives reproduced the insulin-sensitizing effects of central HN. Inhibition of hypothalamic STAT-3 completely negated the effects of IV HN analog on liver, suggesting that the hepatic actions of HN are centrally mediated. This is consistent with the lack of a direct effect of HN on primary hepatocytes. Furthermore, single treatment with a highly-potent HN analog significantly lowered blood glucose in Zucker diabetic fatty rats. Based upon the link of HN with two age-related diseases, we examined if there were age associated changes in HN levels. Indeed, the amount of detectable HN in hypothalamus, skeletal muscle, and cortex was decreased with age in rodents, and circulating levels of HN were decreased with age in humans and mice.

Conclusions

We conclude that the decline in HN with age could play a role in the pathogenesis of age-related diseases including AD and T2DM. HN represents a novel link between T2DM and neurodegeneration and along with its analogues offers a potential therapeutic tool to improve insulin action and treat T2DM.     

Opsonizing activity of fibronectin isolated from the plasma of irradiated rats

A comparative study was made of the opsonizing activity of fibronectin isolated from intact and exposed (7.5 Gy) rat plasma. Fibronectin of both types was shown to possess a virtually the same capacity of increasing the clearance of gelatinized India ink injected intravenously 3 h following thermal affection.     

Analysis of the modifying effect of liver injury on the course and outcome of acute radiation sickness

In studying the aggravating effect of liver injury on the development of radiation sickness in irradiated rats it was found that the death rate increased within the range of minimal and median lethal doses and was not associated with the aggravation of both the haematologic and the hemorrhagic syndromes; it was not related to infectious complications as well. The data are presented on auto-intoxication as a factor aggravating the outcome of the combined radiation injury.     

The level and immunochemical characteristics of fibronectin in the plasma of irradiated rats

The electrophoretic and immunoelectrophoretic methods were used to study fibronectin of blood plasma of intact Wistar rats and of those exposed to 1-10 Gy radiation. The increase in the fibronectin concentration 3 days after irradiation was a function of radiation dose. Possible mechanisms of the hyperfibronectinemia development involving mechanisms of endogenous proteolytic fragmentation of glycoprotein, the increase in the protein synthesis and complexation and inhibition of the rate of fibronectin degradation and elimination are discussed.