Origin of lentoids in experimental teratomas derived from early postimplantation rat embryos

Summary Experimental teratomas derived from renal isografts of early postimplantation rat embryonic shields were analysed histologically for the presence of lentoids and their relationship with other tissues within the tumour. The observations permit the conclusion that in teratomas lentoids originate either from the retinal epithelium or from the ependymal cells of the brain ventricle     

Gastrointestinal helminth community of loggerhead sea turtle Caretta caretta in the Adriatic Sea

We analysed the intestinal helminth community of 70 loggerhead sea turtles Caretta caretta with a curved carapace length ranging from 25 to 85.4 cm, recovered dead in neritic foraging habitats in the Adriatic Sea in 1995 to 2004. The overall prevalence of infection was high (70.0%), with a mean abundance of 36.8 helminth parasites per turtle. Helminth fauna comprised 5 trematodes (Calycodes anthos, Enodiotrema megachondrus, Orchidasma amphiorchis, Pachypsolus irroratus, Rhytidodes gelatinosus) and 3 nematodes (Sulcascaris sulcata, Anisakis spp., Hysterothylacium sp.), with 6 taxa specific for marine turtles. In terms of infection intensity and parasite abundance, O. amphiorchis was the dominant species (mean intensity: 49.8; mean abundance: 12.8), followed by R. gelatinosus (30.5 and 8.3, respectively) and P. irroratus (23.5 and 7.0, respectively), while larval Anisakis spp. exhibited the highest prevalence (34.3%). The intensity of helminth infection ranged from 1 to 302 (mean: 52.6 ± 69.1) and was not correlated with the size of turtles; this relationship held for all species, except R. gelatinosus (rS = 0.556, p < 0.05). In comparison to other marine habitats, the helminth community of Adriatic loggerheads is characterised by higher species diversity (Shannon-Wiener H' = 1.58) and evenness (E = 0.76), and lower dominance values (Berger-Parker d = 0.35), which can be attributed to the life history and feeding ecology of sea turtles in recruited neritic grounds and the diversity of their benthic prey.     

From broadscale patterns to fine-scale processes: habitat structure influences genetic differentiation in the pitcher plant midge across multiple spatial scales

The spatial scale at which samples are collected and analysed influences the inferences that can be drawn from landscape genetic studies. We examined genetic structure and its landscape correlates in the pitcher plant midge, Metriocnemus knabi, an inhabitant of the purple pitcher plant, Sarracenia purpurea, across several spatial scales that are naturally delimited by the midge’s habitat (leaf, plant, cluster of plants, bog and system of bogs). We analysed 11 microsatellite loci in 710 M. knabi larvae from two systems of bogs in Algonquin Provincial Park (Canada) and tested the hypotheses that variables related to habitat structure are associated with genetic differentiation in this midge. Up to 54% of variation in individual‐based genetic distances at several scales was explained by broadscale landscape variables of bog size, pitcher plant density within bogs and connectivity of pitcher plant clusters. Our results indicate that oviposition behaviour of females at fine scales, as inferred from the spatial locations of full‐sib larvae, and spatially limited gene flow at broad scales represent the important processes underlying observed genetic patterns in M. knabi. Broadscale landscape features (bog size and plant density) appear to influence oviposition behaviour of midges, which in turn influences the patterns of genetic differentiation observed at both fine and broad scales. Thus, we inferred linkages among genetic patterns, landscape patterns and ecological processes across spatial scales in M. knabi. Our results reinforce the value of exploring such links simultaneously across multiple spatial scales and landscapes when investigating genetic diversity within a species.     

Of mice and men: teratomas and teratocarcinomas

Teratomas and teratocarcinomas are tumors containing tissue derivatives of all three germ-layers. They can be induced by transplantation of animal embryos to ectopic microenvironment. Development of malignant teratocarcinomas depends on embryonic stage, species-specificity and immunological competence of the host. In the man, teratomas and teratocarcinomas usually represent a subtype of germ-cell tumors but sacrococcygeal teratomas arise from the remnants of the pluripotent primitive streak. Undifferentiated embryonal carcinoma (EC) cells are responsible for the malignancy of experimental mouse teratocarcinomas. Mouse EC cells injected to the adult give rise to tumors and upon injection to early embryos to differentiated tissues--thus resembling normal mouse embryonic stem cells (mESC). Epigenetic changes rather than mutations are associated with transformation of mESC to EC cells. Human EC and ES cell-lines (hESC) contain chromosomal abnormalities and can form teratocarcinoma after transplantation. ES cells are among those proposed for cell replacement therapy in the man. Suicide gene introduction should be recommended prior to their use in vivo to ablate them in case of malignant transformation.     

Bilateral MR volumetry of the amygdala in chronic PTSD patients

Posttraumatic stress disorder (PTSD) patients experience symptoms which implicate dysfunction of emotional memory circuits, and possible damage of the amygdala. Laterality differences in activity of the amygdala have been reported in PTSD patients, with presumed adaptive plasticity in the hippocampus and the amygdala. The aim of this study was to investigate possible interhemispheric differences of amygdalar volume in chronic PTSD patients, with calculation of right-to-left volume ratios. Bilateral magnetic resonance (MR) volumetry was applied in 11 chronic PTSD patients. The mean right amygdalar volume of our patients was significantly smaller than the left one (p = 0.031), with the right-to-left volume ratio of 0.96 +/- 0.06. This tendency towards smaller right amygdala may be an acquired effect as a result of stress-induced plasticity, however we can not exclude the possibility of a predisposing condition.     

Synthesis and antiproliferative activity of two new tiazofurin analogues with 2'-amido functionalities

Two novel tiazofurin analogues 2 and 3 were synthesized starting from d-glucose. The key step of the synthesis was the efficient one-step hydrogen sulfide-mediated conversion of 2-azido-3-O-acyl-ribofuranosyl cyanides to the corresponding 2-amido thiocarboxamides. Compounds 2 and 3 were evaluated for their in vitro antiproliferative activity against certain human tumour cell lines. Remarkably, compound 2 was found to be 570-fold more potent than tiazofurin against MCF-7 cells, while compound 3 showed the most powerful cytotoxicity against HT-29 cancer cells, being almost 100-fold more active than tiazofurin.     

Detection of salivary interleukin 2 and interleukin 6 in patients with burning mouth syndrome

The etiology of BMS remains unknown. Role of various cytokines has been implicated in the development of BMS. The aim of this study was to evaluate levels of salivary IL-2 and IL-6 in patients with BMS, compared with age-matched healthy volunteers (control group). Whole saliva from 30 patients with BMS, age range 55-65, was tested for the presence of IL-6 and IL-2 by enzyme immunoassay. Control group consisted of 30 healthy participants, aged 55-65 years. Saliva IL-2 concentrations in BMS were significantly increased in patients compared to healthy subjects: mean 34.1 +/- 9.7 versus 7.3 +/- 3.0 pg/mL; P < .001. Patients with BMS had significantly higher concentrations of IL-6 compared to control: mean 30.8 +/- 5.6 versus 5.2 +/- 2.8 pg/mL; P < .001. In patients with BMS, IL-2 and IL-6 levels in saliva are elevated, correlating with the severity of illness.     

Distribution of Several Activating and Inhibitory Receptors on CD3<Superscript>−</Superscript>CD16<Superscript>+</Superscript> NK Cells and Their Correlation with NK Cell Function in Healthy Individuals

The aim of this study was to estimate the distribution and density of a representative set of activating and inhibitory receptors on gated natural killer (NK) cells, as well as on their bright and dim subsets, and to correlate the receptor expression with NK cell activity for healthy individuals on CD3⁻CD16⁺ NK cells. We show that in 43 healthy controls NK cell activity against K562 target cells was 37.34% (E:T, 80:1) by standard chromium release assay. The expression of receptors on NK cells and their subsets was analyzed by flow cytometry. The cytotoxic CD3⁻CD16^bright NK subset constituted 78.97%, while the regulatory CD3⁻CD16^dim NK subset constituted 21.03% of NK cells. We show the distribution of NKG2D, CD161, CD158a, and CD158b receptors on CD3⁻CD16⁺ NK cells in peripheral blood lymphocytes (PBLs), on gated NK cells, and on the CD3⁻CD16^bright and CD3⁻CD16^dim subsets. Contrary to CD158a and CD158b killer immunoglobulin-like receptors (KIRs), there is a significant positive correlation of NKG2D and CD161 expression with NK cytotoxicity. We show the kinetics of change in CD3⁻CD16⁺NK/K562 conjugate composition, together with the stronger target binding capacity of CD16^bright NK cells. Furthermore, we show that after coculture of PBLs with K562 the expression of CD107a, a degranulation marker, on CD3⁻CD16⁺NK cells and subsets is time dependent and significantly higher on the cytotoxic CD3⁻CD16^bright NK subset. The novel data obtained regarding expression of NK cell activating and inhibitory receptors for healthy individuals may aid in detecting changes that are associated with various diseases.