Protection from type 1 diabetes by invariant NK T cells requires the activity of CD4+CD25+ regulatory T cells

Invariant NK T (iNKT) cells regulate immune responses, express NK cell markers and an invariant TCR, and recognize lipid Ags in a CD1d-restricted manner. Previously, we reported that activation of iNKT cells by alpha-galactosylceramide (alpha-GalCer) protects against type 1 diabetes (T1D) in NOD mice via an IL-4-dependent mechanism. To further investigate how iNKT cells protect from T1D, we analyzed whether iNKT cells require the presence of another subset(s) of regulatory T cells (Treg), such as CD4+ CD25+ Treg, for this protection. We found that CD4+ CD25+ T cells from NOD.CD1d(-/-) mice deficient in iNKT cell function similarly in vitro to CD4+ CD25+ T cells from wild-type NOD mice and suppress the proliferation of NOD T responder cells upon alpha-GalCer stimulation. Cotransfer of NOD diabetogenic T cells with CD4+ CD25+ Tregs from NOD mice pretreated with alpha-GalCer demonstrated that activated iNKT cells do not influence the ability of T(regs) to inhibit the transfer of T1D. In contrast, protection from T1D mediated by transfer of activated iNKT cells requires the activity of CD4+ CD25+ T cells, because splenocytes pretreated with alpha-GalCer and then inactivated by anti-CD25 of CD25+ cells did not protect from T1D. Similarly, mice inactivated of CD4+ CD25+ T cells before alpha-GalCer treatment were also not protected from T1D. Our data suggest that CD4+ CD25+ T cells retain their function during iNKT cell activation, and that the activity of CD4+ CD25+ Tregs is required for iNKT cells to transfer protection from T1D.     

The thermal properties of some nests of the Eurasian Tree Sparrow Passer montanus

Using an electronic apparatus simulating a bird roosting in a nest at night, we examined the insulating qualities of Eurasian Tree Sparrow (Passer montanus) nests built in nest boxes under winter conditions. Nests of different construction were compared with an empty box, and with roosting in open air. Energy savings in an empty box accounted for 18%, in boxes with incomplete nests for 23% and in boxes with complete nests up to 36%. The insulating value of nests mostly depended on their completeness and the proportion of feathers in the lining.     

Prognostic significance of Ki67-negative blast cell clone in the high risk group of children treated for acute myeloid leukaemia

The aim of this study was to demonstrate the value of immunocytochemical staining of Ki67 antigen expression in blast cells of children with acute myeloid leukemia (AML) and to evaluate its correlation with treatment failure. The material included bone marrow specimens obtained during induction treatment from 46 children treated for AML between 1998-2003. Immunocytochemical staining for Ki67 was based on the ABC technique. Expression of Ki67 antigen on day 0 of induction treatment was confirmed in all patients. The percentage of immunopositive blasts ranged from 88.4% to 99.8% (mean 91.8%). On day 15, according to chemotherapy response, patients were divided into two groups: G1-36 children who responded to induction treatment and reached remission (blast level 5%, low risk group) and G2-10 patients who did not meet remission criterion (blast level > 5%) and were assigned to the high risk (HR) group. Out of 10 children assigned to this group, Ki67 expression in blast cells was confirmed in 4 cases. The fraction of immunopositive blasts ranged from 78.4% to 88.6%. In the other 6 cases, blasts were Ki67-negative. In 12-month period after beginning the treatment, 18 cases of treatment failure (including 7 deceases) were observed in both groups. Five deaths, observed in the HR group, concerned the patients characterized by Ki67-negative blasts. The results indicate a possible correlation between the Ki67-immunonegative blast pattern on day 15 of treatment induction and early decease of AML children assigned to HR group.     

Antioxidative and anti-diabetic effects of amaranth (Amaranthus esculantus) in streptozotocin-induced diabetic rats

The anti-diabetic and antioxidative effect of amaranth grain (AG) and its oil fraction (AO) was studied in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into four groups after induction of STZ-diabetes: normal control; diabetic control; diabetic-AG supplement (500 g kg(-1) diet); diabetic-AO supplement (100 g kg(-1) diet) and fed experimental diets for 3 weeks. Serum glucose, insulin, activities of serum marker enzymes of liver function and liver cytosolic antioxidant enzymes were measured. The AG and AO supplement significantly decreased the serum glucose and increased serum insulin level in diabetic rats. Serum concentration of liver function marker enzymes, GOT and GPT, were also normalized by AG and AO treatment in diabetic rats. Liver cytosolic SOD and GSH-reductase activities were significantly increased, and catalase, peroxidase and GSH-Px activities were decreased in diabetic rats. AG and AO supplement reverted the antioxidant enzyme activities to near normal values. Hepatic lipid peroxide product was significantly higher, and GSH content was decreased in diabetic rats. However, AG and AO supplement normalized these values. Our data suggest that AG and AO supplement, as an antioxidant therapy, may be beneficial for correcting hyperglycaemia and preventing diabetic complications.     

Cell Proliferation in the Adult Rat Rostral Migratory Stream Following Exposure to Gamma Irradiation

Summary One of the few areas of the adult CNS, that are known to be competent for neuronal proliferation, is the subventricular zone (SVZ) lining the brain lateral ventricles. Cells proliferating in the SVZ migrate along a defined pathway, the rostral migratory stream (RMS), where their proliferation continues until reaching the olfactory bulb.1. In relation to the fact that brain is, in general, regarded as a radioresistant organ composed from non dividing cells, the aim of the present study was to investigate effect of ionizing radiation on proliferating cell numbers in the RMS of adult rats.2. Male Wistar rats were investigated 25 and 80 days after whole body gamma irradiation with the dose of 3 Gy. Dividing cells were labeled by bromodeoxyuridine (BrdU). BrdU-positive cells were counted by Disector program. The mean number of BrdU⁺ cells in the whole RMS and in its individual parts (vertical arm, elbow, and horizontal arm) was evaluated.3. Temporary increase in proliferating cell number (by 30%) was seen in the whole RMS at the 25th day after irradiation.4. The most expressive increase occurred in the vertical arm (by 60%) and elbow (about 37%). The values reduced till the 80th day after exposure.Our results show that ionizing irradiation significantly influences the extent of cell proliferation and migration in the adult rat RMS.     

Association between the MLH1 gene and longevity

Perturbations in genomic stability result in cancer, a reduced life span, and premature aging. MLH1 is a mismatch repair enzyme that acts to maintain genomic stability, and a loss of MLH1 increases cancer incidence and apoptosis resistance, which suggests a link between MLH1 and longevity. We found here that MLH1 is associated with longevity by comparing a centenarian group with a control group. Our data indicate a critical role for MLH1 in longevity.     

Furin is an endogenous regulator of alpha-secretase associated APP processing

Constitutive and PKC-regulated alpha-secretase pathways have been reported to produce the secreted form of alpha-secretase-derived APP (sAPPalpha). Here, we examined putative role of furin in the regulation of alpha-secretase activity in vitro and in vivo. Overexpression of the prodomain of furin and infection with a furin-specific inhibitor significantly reduced the levels of sAPPalpha regardless of PKC activity, whereas total APP levels remained unchanged. Furin mRNA levels in the brains of AD patients and Tg2576 mice were significantly lower than those in controls, whereas ADAM10 and TACE mRNA levels were much alike between Tg2576 and littermate mice. Moreover, the injection of furin-adenovirus into Tg2576 mouse brains markedly increased alpha-secretase activity and reduced beta-amyloid protein (Abeta) production in infected brain regions. Our results suggest that furin enhances alpha-secretase activity via the cleavage of ADAM10 and TACE, and that attenuated furin activity is connected to the production of Abeta.     

The C-type Arabidopsis thioredoxin reductase ANTR-C acts as an electron donor to 2-Cys peroxiredoxins in chloroplasts

2-Cys peroxiredoxins (Prxs) play important roles in the antioxidative defense systems of plant chloroplasts. In order to determine the interaction partner for these proteins in Arabidopsis, we used a yeast two-hybrid screening procedure with a C175S-mutant of Arabidopsis 2-Cys Prx-A as bait. A cDNA encoding an NADPH-dependent thioredoxin reductase (NTR) isotype C was identified and designated ANTR-C. We demonstrated that this protein effected efficient transfer of electrons from NADPH to the 2-Cys Prxs of chloroplasts. Interaction between 2-Cys Prx-A and ANTR-C was confirmed by a pull-down experiment. ANTR-C contained N-terminal TR and C-terminal Trx domains. It exhibited both TR and Trx activities and co-localized with 2-Cys Prx-A in chloroplasts. These results suggest that ANTR-C functions as an electron donor for plastidial 2-Cys Prxs and represents the NADPH-dependent TR/Trx system in chloroplasts.     

Brush border membrane binding properties of Bacillus thuringiensis Vip3A toxin to Heliothis virescens and Helicoverpa zea midguts

The binding properties of Vip3A, a new family of Bacillus thuringiensis insecticidal toxins, have been examined in the major cotton pests, Heliothis virescens and Helicoverpa zea. Vip3A bound specifically to brush border membrane vesicles (BBMV) prepared from both insect larval midguts. In order to examine the cross-resistance potential of Vip3A to the commercially available Cry1Ac and Cry2Ab2 toxins, the membrane binding site relationship among these toxins was investigated. Competition binding assays demonstrated that Vip3A does not inhibit the binding of either Cry1Ac or Cry2Ab2 and vice versa. BBMV protein blotting experiments showed that Vip3A does not bind to the known Cry1Ac receptors. These distinct binding properties and the unique protein sequence of Vip3A support its use as a novel insecticidal agent. This study indicates a very low cross-resistance potential between Vip3A and currently deployed Cry toxins and hence supports its use in an effective resistance management strategy in cotton.