The alpha7 nicotinic receptors in human fetal brain and spinal cord

The alpha7 nicotinic acetylcholine receptor subtype is believed to be involved in the regulation of neuronal growth, differentiation and synapse formation during the development of the human brain. In this study the expression of the alpha7 nicotinic acetylcholine receptor was investigated in human fetal brain and spinal cord of 5-11 weeks gestational age. Both the specific binding of [125I]alpha-bungarotoxin to prenatal brain membranes and the expression of alpha7 mRNA were significantly higher in the pons, medulla oblongata, mesencephalon and spinal cord of 9-11 weeks gestational age compared with cerebellum, cortex and subcortical forebrain. A significant positive correlation between gestational age and the expression of alpha7 mRNA was observed in all brain regions except cortex. A positive correlation was also observed between the gestational age and the [125I]alpha-bungarotoxin binding in the pons, medulla oblongata, mesencephalon, and cerebellum. Consequently, a significant relationship between the alpha7 mRNA levels and the binding sites for [125I]alpha-bungarotoxin was found in the fetal brain. The increasing levels of the alpha7 nicotinic acetylcholine receptor during the first trimester support the important role of nAChRs for the development of the central nervous system.     

Characterization of the first growth hormone gene sequence for a passerine bird--the pied flycatcher (Ficedula hypoleuca).

While the growth hormone (GH) gene has been characterized in a broad range of vertebrates, surprisingly little is known about this gene in birds. In order to extend knowledge of the GH gene in avian species and non-domestic species, the pied flycatcher (Ficedula hypoleuca) GH gene has been sequenced in this study. The overall average pairwise sequence divergence level was 0.08 among all available avian sequences and 0.27 among other taxa. However, the overall genetic organization of the gene is quite conserved. The similarity of the GH gene sequence of pied flycatchers with those of chicken and duck suggests that the rapid bursts of molecular evolution observed in mammalian and fish GH have not occurred during the divergence of passerine and non-passerine birds.     

Lead-dithiocarbamate interaction

Dithiocarbamates are known to markedly increase tissue uptake of lead and potentiate toxic effects of lead in rats. Effects of the interaction between lead and diethyldithiocarbamate (DTC) on the enzyme δ-aminolevulinic acid dehydratase, ALAD, were studied in primary cultures of rat hepatocytes, incubated with lead acetate, PbAc, or lead-diethyldithiocarbamate complex, Pb(DTC)₂, labeled with²⁰³Pb. Incubation of cells with the lipophilic Pb(DTC)₂ complex caused a more rapid and stronger inhibition of ALAD activity than did PbAc. The effects on ALAD activity could be related to the cellular uptake of lead. Thus, a much higher and more rapid cellular uptake of lead was found following incubation with Pb(DTC)₂ than with PbAc. Pb(DTC)₂ inhibited ALAD activity also in vitro when incubated with purified ALAD enzyme. It is suggested that the increased inhibition of ALAD activity by Pb(DTC)₂ is owing to facilitated cellular transport of lead in the complexed form and that complexing lead with DTC could serve as an experimental model in order to obtain high cellular concentrations of lead.     

Induction of cytotoxic T lymphocytes specific for a syngeneic tumor expressing the E6 oncoprotein of human papillomavirus type 16.

Human papillomavirus (HPV) type 16 has been implicated in the etiology of cervical carcinomas, but it is unknown whether HPV-specific immunity can function in controlling the growth of HPV-associated carcinomas. We previously demonstrated that CD8+ T lymphocytes can inhibit the in vivo outgrowth of murine tumor cells transfected with the HPV-16 E7 gene and have now established a murine model to study the CTL responses to the E6 oncoprotein of HPV-16. Immunization of C3H/HeN mice with syngeneic fibroblasts expressing a transfected HPV-16 E6 gene induced regression of transplanted tumors expressing this gene. Populations of CTL isolated from the spleens of mice whose E6+ tumors had regressed were shown to specifically lyse E6+ target cells. The cytolytic activity was mediated by CD8+ CTL in a MHC restricted pattern. These data and our previous findings with transfected tumor cells expressing the E7 gene, support the conclusion that tumor cells associated with HPV-16 can be inhibited by CTL specific for molecules encoded by the HPV-16 E6 and E7 genes.     

Redistribution of sediments in three Swedish lakes

Sedimentation and redistribution of fine sediments in three Swedish lakes of different character have been investigated using settling sediment traps. The bottom shear stress from wind generated waves are calculated and the extension of erodable bottom area is related to wind conditions. Wave induced erosion and deposition during and after cessation of storms in different parts of a lake are discussed theoretically. It is shown that a single one year storm may redistribute more bottom material than the accumulated resuspension caused by frequent but smaller wind events. The settling sediment trap deposition and the concentration of suspended solids are related to the extension of erodable bottom area of particular storms. It is found that in lakes where there are relatively large areas of erosion bottoms, resuspended material from the part of the lake most susceptible to strong winds of large fetch constitutes a major part of the settled material on deep bottoms.     

Mouse monoclonal antibodies with specificity for the melanoma-associated ganglioside disialyllactosylceramide (GD3) also react with the structural analogue disialylparagloboside

A mouse monoclonal IgM antibody, 4.2, has previously been shown to bind preferentially to the surface of human malignant melanoma cells and to have specificity for the GD3 ganglioside (NeuAc alpha 2----8NeuAc alpha 2----3Gal beta 1----4GlcCer). Using overlay of antibodies on thin-layer chromatograms with glycolipids of various sources, it was shown that antibody 4.2, a further IgM and two IgG3 mouse monoclonal antibodies, selected on the basis of reactivity with GD3, also bound with similar strength to the structural analogue NeuAc alpha 2----8NeuAc alpha 2----3Gal beta 1----4GlcNac beta 1----3Gal beta 1----4GlcCer or disialylparagloboside. The SK-MEL 28 melanoma cell line used for immunization was shown to contain a large amount of GD3 but to lack disialylparagloboside. The demonstrated cross-reactivity may be of importance when considering the use of these antibodies for biochemical and medical purposes.     

Clustering and canonical correspondence analysis of phytoplankton and environmental variables in Swedish lakes

Phytoplankton data consisting of 145 species from a limnological study of lakes from relatively undisturbed areas throughout Sweden were analysed in relation to 11 physical and chemical environmental variables. Three multivariate methods were applied: WPGMA clustering and TWINSPAN for classification, and detrended canonical correspondence analysis (DCCA), a recent technique which extracts ordination axes that can be related directly to variation in the environment. Three types of lakes were recognized consistently: acid humic lakes with Gonyostomum semen as the dominant species, very acid impoverished lakes with rather few, stress-tolerant species, and subarctic lakes with low total biomass but with a varied phytoplankton flora. DCCA allowed a straightforward display of the locations of lakes and species along environmental gradients (including the acidification gradient) reflected in phytoplankton composition. It is suggested that such analyses may be a useful tool for the early detection of environmental change.     

Lack of evidence for a genetic association between FGF20 and Parkinson's disease in Finnish and Greek patients

Background

Fibroblast growth factor 20 (FGF20) is a neurotrophic factor preferentially expressed in the substantia nigra of rat brain and could be involved in dopaminergic neurons survival. Recently, a strong genetic association has been found between FGF20 gene and the risk of suffering from Parkinson's disease (PD). Our aim was to replicate this association in two independent populations.

Methods

Allelic, genotypic, and haplotype frequencies of four biallelic polymorphisms were assessed in 151 sporadic PD cases and 186 controls from Greece, and 144 sporadic PD patients and 135 controls from Finland.

Results

No association was found in any of the populations studied.

Conclusion

Taken together, these findings suggest that common genetic variants in FGF20 are not a risk factor for PD in, at least, some European populations.