The Effects of Whole Body Gamma Irradiation on Mice, Age-Related Behavioral, and Pathophysiological Changes.

We designed a study with the objective to determine the long-term radiation effects of gamma rays, originating from a single shot of Co60 at a dose of 2 Gy on the 7-month-old male mice of the ICR line in 30 days after the irradiation. The aim of this study was to characterize the behavior of animals using the Open Field test, immuno-hematological status, and morpho-functional changes in the central nervous system of mice. Irradiated animals displayed significantly different behavior in the OF in comparison with the control group. The radiation damage was confirmed by assessing the ratio of leukocytes in the peripheral blood of mice at a later date after exposure to Co60. After irradiation, a decrease in the glioneuronal complex was observed in the irritated group as well as histological changes of brain cells. To sum up, not only was the hematological status of mice altered upon the total gamma irradiation, but also their behavior, which was most probably due to significant alterations in the CNS. Study of influence of ionizing radiation on female mice, comparison between different age groups. Open Field test on the 30 days after 2 Gy of γ-rays and histological analysis indicated changes in behavioral patterns, leucocytes, and brain tissue.

Oxidation of placental insulin and insulin-like growth factor receptors in mothers with diabetes mellitus or preeclampsia complicated with intrauterine growth restriction.

Placental insulin receptor (IR) and insulin-like growth factor receptors (IGFRs) are essential for fetal growth. We investigated structural changes of these receptors exposed to increased oxidative stress in mothers diagnosed with diabetes mellitus (DM) or preeclampsia (PE) complicated with intrauterine growth restriction. Increased amount of IR and decreased amounts of IGF1R and IGF2R were found in both pathologies, accompanied by significant elevation in protein carbonyls. When isolated receptors were examined, increased carbonylation of IR and IGF1R in PE placentas was detected, whereas the amounts of carbonylated IR and IGF1R were similar in DM and healthy placentas. Carbonylation status of IGF2R did not change due to pathology, confirming the detrimental role of primary structure and conformation in oxidative susceptibility. Ligand binding was similar in all three groups of samples and did not seem to be affected by receptor oxidation. Since babies delivered by mothers with PE were smaller than the referent population, increased carbonylation of receptors might have affected downstream receptor signaling post-ligand binding.

Influence of placental mannose/n-acetyl glucosamine-binding proteins on the interaction of insulin and insulin-like growth factors with their receptors.

Placenta is a source of carbohydrate-binding proteins that function as molecular scavengers, but they could also be involved in interactions that assist in metabolic control. Mannose/N-acetyl-glucosamine (Man/GlcNAc)-binding proteins from placenta were isolated and their reactivity towards placental insulin and insulin-like growth factor receptors (IR and IGF-Rs) was analyzed. The lectins reduced the binding of insulin and IGF-I in a dose-dependent manner, while almost no effect was observed on the binding of IGF-II. The shape of the inhibition curves changed, suggesting altered binding specificity. The presence of sugar could not reverse completely the effect of the lectins, implicating both lectin-sugar and protein-protein conformational recognition. Since biological molecules in our experimental system were those that are in close relation in vivo, placental Man/GlcNAc-specific lectins may be regarded as potential allosteric modulators of ligand-receptor interactions in a system of homologous ligands, selectively affecting only binding to tyrosine kinase type receptors (IR and IGF-1R).

Association between the pattern of IGFBP-1 alteration and the glucose/insulin metabolic control.

Little is known on the possible association between impaired glucose/insulin metabolism, the pattern of IGFBP-1 phosphorylation and the complex formation with other serum proteins. In this study, the concentration, isoform, multimer and complex pattern of IGFBP-1 was compared in healthy persons and patients with type 2 diabetes mellitus or with hypoglycemia. Concentrations of insulin and IGFBP-1 were determined by radioimmunoassay. Metal affinity and immunoaffinity chromatography were used for the separation of molecular forms of IGFBP-1, which were detected by immunoblotting and SELDI. The counter directional change in insulin and IGFBP-1 concentrations, expressed as a factor that takes into consideration the rate of insulin increase and IGFBP-1 decrease after glucose intake was approximately twice more pronounced in patients with diabetes than in healthy and hypoglycemic persons. The alteration in the phosphorylation pattern of IGFBP-1 due to diabetes or hypoglycemia was not observed. IGFBP-1 multimers found in the circulation of patients with diabetes type 2 differed from those detected in the circulation of others: there were 3 molecular forms between 90 and 100 kDa (compared to one in patients with hypoglycemia or 2 in healthy persons), 2 of which were α (2)M-reactive and one not. These results suggest a possible greater involvement of IGF system in glucose regulation in patients with diabetes type 2.

Isolated compared to membrane-bound receptors exhibit altered insulin/IGF interaction.

Insulin and insulin-like growth factors (IGFs) bind to their cognate receptors with high affinities, but due to their homology they may cross-react with each other's receptors. We performed a series of binding studies to reanalyze the cross-reactivity of insulin, IGF-I, and IGF-II to affinity-purified insulin (IR) and type 2 IGF receptors (IGF-2R) from human placental membranes. IR and IGF-2R were purified using insulin- and mannose-6-phosphate affinity chromatography (I-AC and M6P-AC). Binding studies were performed with (125)I-labeled and unlabeled ligands. According to immunoblotting, the only receptor species isolated by I-AC was IR, whereas the only receptor isolated by M6P-AC was IGF-2R. Isolated IR reacted to similar extent with (125)I-labeled insulin and (125)I-labeled IGF-II and significantly less with (125)I-labeled IGF-I, implicating predominance of IR-A. The affinity of IR towards heterologous ligands increased after its separation from other membrane proteins. Affinity-purified IGF-2R was almost unable to bind ligands under experimental conditions used in this work, but when incubated with (125)I-labeled ligands prior to affinity chromatography, IGF-2R interacted not only with IGF-II, but to a certain extent with the other two ligands. In the competitive M6P-AC, the binding of labeled ligands was inhibited with either homologous or heterologous ligands, in a dose dependent manner. In competitive ligand-blotting, specific interactions between (125)I-labeled insulin and IR, and (125)I-labeled IGF-II and IGF-2R were also inhibited with all unlabeled ligands, although to a different extent. The results presented in this work imply that isolation of IR an IGF-2R from their membrane milieu increases their reactivity towards all members of the insulin/IGF ligand family.

Alterations of IGF-binding proteins in patients with alcoholic liver cirrhosis.

The protein synthetic activity of the liver is diminished in cirrhosis. The aim of this study was to investigate possible changes in the serum IGF-IGFBP system among patients with alcoholic liver cirrhosis (ALC). The results obtained demonstrated that serum IGF-I and IGF-II concentrations were significantly lower in patients with ALC than in healthy persons (P=0.0008 for IGF-I and 0.0002 for IGF-II). The IGFBP profile was markedly altered and the 34 kDa IGFBP from patients had higher affinity towards 125I-IGF-II compared to the 34 kDa IGFBP of control individuals. Moreover, the 40-45 kDa IGFBP (in isolated complex with 125I-IGF-II) exhibited diminished interaction with concanavalin A, wheat germ, and breadfruit lectins. Modification of the glyco-component of the 40-45 kDa IGFBP seems to be an early event in ALC since change in reactivity towards lectins was noticed in patients with ALC classified as Child score A, whose serum IGF-I and IGF-II levels were within reference limits (the existence of carbohydrate microheterogeneity of this IGFBP was also assessed by lectin-affinity electrophoresis). It is possible that these biochemical alterations may affect the functional activity of the IGFs by changing the dynamics and distribution of these growth factors in the organism.

Serum insulin-like growth factor (IGF)-II is more closely associated with liver dysfunction than is IGF-I in patients with cirrhosis.

The aim of this investigation was to determine the total concentrations of the insulin-like growth factors (IGF-I and IGF-II) in the blood serum of patients with liver cirrhosis and to evaluate their association with the condition. Cirrhosis was alcohol induced (n=27), of viral origin (n=17) or due to combined or other causes (n=21) and was moderate or severe in similar numbers of cases (Child A: n=21; Child B: n=21; Child C: n=23). While serum levels of both peptides were lower in patients than in age-matched healthy subjects (n=81), there was considerable overlap into the lower normal range for IGF-I. Moreover, no correlation between disease severity (Child score) and serum IGF-I was observed. Since a total of 78% of the results for IGF-II were outside the normal range (95% confidence interval) and serum concentrations were correlated with Child score (P=0.007), it is suggested that serum IGF-II concentrations may reflect compromised hepatic function more closely than IGF-I.