The influence of land use change on landslide susceptibility zonation: the Briga catchment test site (Messina, Italy).

The spatial distribution of landslides is influenced by different climatic conditions and environmental settings including topography, morphology, hydrology, lithology, and land use. In this work, we have attempted to evaluate the influence of land use change on landslide susceptibility (LS) for a small study area located in the southern part of the Briga catchment, along the Ionian coast of Sicily (Italy). On October 1, 2009, the area was hit by an intense rainfall event that triggered abundant slope failures and resulted in widespread erosion. After the storm, an inventory map showing the distribution of pre-event and event landslides was prepared for the area. Moreover, two different land use maps were developed: the first was obtained through a semi-automatic classification of digitized aerial photographs acquired in 1954, the second through the combination of supervised classifications of two recent QuickBird images. Exploiting the two land use maps and different land use scenarios, LS zonations were prepared through multivariate statistical analyses. Differences in the susceptibility models were analyzed and quantified to evaluate the effects of land use change on the susceptibility zonation. Susceptibility maps show an increase in the areal percentage and number of slope units classified as unstable related to the increase in bare soils to the detriment of forested areas.

Elf-1 contributes to the function of the complex interleukin (IL)-2-responsive enhancer in the mouse IL-2 receptor alpha gene.

Lymphocytes regulate their responsiveness to IL-2 through the transcriptional control of the IL-2R alpha gene, which encodes a component of the high affinity IL-2 receptor. In the mouse IL-2R alpha gene this control is exerted via two regulatable elements, a promoter proximal region, and an IL-2-responsive enhancer (IL-2rE) 1.3 kb upstream. In vitro and in vivo functional analysis of the IL-2rE in the rodent thymic lymphoma-derived, CD4- CD8- cell line PC60 demonstrated that three separate elements, sites I, II, and III, were necessary for IL-2 responsiveness; these three sites demonstrate functional cooperation. Site III contains a consensus binding motif for members of the Ets family of transcription factors. Here we demonstrate that Elf-1, an Ets-like protein, binds to site III and participates in IL-2 responsiveness. In vitro site III forms a complex with a protein constitutively present in nuclear extracts from PC60 cells as well as from normal CD4- CD8- thymocytes. We have identified this molecule as Elf-1 according to a number of criteria. The complex possesses an identical electrophoretic mobility to that formed by recombinant Elf-1 protein and is super-shifted by anti-Elf-1 antibodies. Biotinylated IL-2rE probes precipitate Elf-1 from PC60 extracts provided site III is intact and both recombinant and PC60-derived proteins bind with the same relative affinities to different mutants of site III. In addition, by introducing mutations into the core of the site III Ets-like motif and comparing the corresponding effects on the in vitro binding of Elf-1 and the in vivo IL-2rE activity, we provide strong evidence that Elf-1 is directly involved in IL-2 responsiveness. The nature of the functional cooperativity observed between Elf-1 and the factors binding sites I and II remains unresolved; experiments presented here however suggest that this effect may not require direct interactions between the proteins binding these three elements.

Near-field coupling of a single fluorescent molecule and a spherical gold nanoparticle.

Near-field coupling of a single gold nanoparticle (GNP) to a single fluorescent molecule is investigated here for varying separation d between the two. While the emission quantum efficiency of the coupled system generally decreases for d!0, a pronounced near-field enhancement is observed under certain conditions, partly outweighing the efficiency loss at small distances. We report on optimizing these conditions by varying the excitation field direction and the three-dimensional relative configuration between the GNP and the fluorophore. Furthermore, we examine how the sphere diameter, the surrounding medium, as well as the absorption and emission wavelengths of the molecular dipole influence the fluorescence yield. Our results are of high practical relevance for all GNP-mediated application fields such as fluorescence microscopy, scattering near-field optical microscopy, bioanalytics, and medical applications.

Characterization of a new tissue-specific transcription factor binding to the simian virus 40 enhancer TC-II (NF-kappa B) element.

We have biochemically and functionally characterized a new transcription factor, NP-TCII, which is present in nuclei from unstimulated T and B lymphocytes but is not found in nonhematopoietic cells. This factor has a DNA-binding specificity similar to that of NF-kappa B but is unrelated to this or other Rel proteins by functional and biochemical criteria. It can also be distinguished from other previously described lymphocyte-specific DNA-binding proteins.

Comparing Landslide Maps: A Case Study in the Upper Tiber River Basin, Central Italy.

/ The preparation of landslide maps is an important step in any landslide hazard assessment. Landslides maps are prepared around the world, but little effort is made to assess their reliability, outline their main characteristics, and pinpoint their limitations. In order to redress this imbalance, the results of a long-term research project in the Upper Tiber River basin in central Italy are used to compare reconnaissance and detailed landslide inventory maps, statistical and geomorphologically based density maps, and landslide hazard maps obtained by multivariate statistical modeling. An attempt is made to discuss advantages and limitations of the available maps, outlining possible applications for decision-makers, land developers, and environmental and civil defence agencies. The Tiber experiment has confirmed that landslides can be cost-effectively mapped by interpreting aerial photographs coupled with field surveys and that errors and uncertainties associated with the inventory can be quantified. The experiment has shown that GIS makes it easy to prepare landslide density maps and facilitates the production of statistically based landslide hazard models. The former supply an overview of the distribution of landslides that is easily comprehended but do not provide insight on the causes of instability. The latter, giving insight into the causes of instability, are diagnostically powerful, but are difficult to prepare and exploit.

A PCR-based assay for reporter gene expression.

Transient transfection is a widely used tool for the identification of cis-acting regulatory elements. These elements are detected by their effect on the expression of a reporter gene, which is quantified by measuring the reporter gene product in the form of mRNA, protein (hGH), or enzymes (CAT, luciferase). Measurements of mRNA levels have several advantages over enzyme or protein assays. However, mRNA quantification by RNase protection or S1 mapping has considerably lower signal-to-background ratio than protein assays and is therefore less sensitive. In this paper we report the development of a system that takes advantage of the polymerase chain reaction (PCR) to quantify rabbit beta-globin reporter gene expression. Cells are co-transfected with constructs whose activity is to be tested and a reference plasmid with a small deletion in the second exon of the beta-globin gene. We show that the ratio of the two amplified cDNA signals is a highly reliable measure of test gene expression. The sensitivity of this assay is at least 1000-fold higher than RNase protection.

Activity and interleukin 1 responsiveness of SV40 enhancer motifs in a rodent immature T cell line.

We have analysed the enhancer activity and the interleukin 1 (IL1) responsiveness of individual motifs of the SV40 enhancer in an immature rodent T cell line, PC60. Transient transfection assays showed that tetramers of GT-I plus GT-IIC motifs, the TC-II or the P motif have significant enhancer activity in PC60, while neither Octamer nor SphI+II motifs have a detectable effect on promoter strength. Two motifs, TC-II and P, strongly respond to stimulation by IL1. DNase I and methylation protection experiments with nuclear extracts show specific footprints in the TC-II region of the SV40 enhancer. Exposure of PC60 cells to IL1 increases their intensity. The TC-II sequence forms several complexes detected in band shift assays. The molecules involved all have similar sequence specificity as NF-kappa B. Surprisingly, band shifts with extracts from control or IL1 treated cells differ only slightly. However, if GTP is added to the binding reactions the intensity of bands formed by extracts from control cells is strongly reduced, whereas extracts from IL1 treated cells form a single retarded complex that co-migrates with NF-kappa B from a pre-B cell line. The results suggest that in PC60 IL1 induces NF-kappa B activity by activating molecules that are already in the nucleus.

Interleukins (IL)-1 and IL-2 control IL-2 receptor alpha and beta expression in immature thymocytes.

Functional high-affinity interleukin-2 receptors (IL-2R) contain three transmembrane proteins, IL-2R alpha, beta and gamma. We have investigated the expression of IL-2R alpha and beta genes in immature mouse thymocytes. Previous work has shown that during differentiation these cells transiently express IL-2R alpha on their surface. Stimulation of IL-2R alpha+ and IL-2R alpha- immature thymocytes with phorbol 12-myristate 13-acetate and calcium ionophore induces synthesis of IL-2R alpha and IL-2R beta mRNA. Most of this response depends on autocrine stimulation by IL-2. IL-1 synergizes with IL-2 to induce a 120-fold increase in IL-2R alpha mRNA and a 14-fold increase in IL-2R beta mRNA levels. A large proportion of the stimulated cells contains both transcripts. These interleukins do not induce any differentiation to more mature phenotypes. Collectively, these results show that IL-2 plays a major role in the regulation of IL-2R expression in normal immature thymocyte. We suggest that this response to interleukins may be part of a homeostatic mechanism to increase the production of immature thymocytes during stress.

Interaction of STAT5 dimers on two low affinity binding sites mediates interleukin 2 (IL-2) stimulation of IL-2 receptor alpha gene transcription.

Stimulation of the interleukin 2 receptor alpha (IL-2Ralpha) gene by IL-2 is important for the proliferation of antigen-activated T lymphocytes. IL-2 regulates IL-2Ralpha transcription via a conserved 51-nucleotide IL-2 responsive enhancer. Mouse enhancer function depends on cooperative activity of three distinct sites. Two of these are weak binding sites for IL-2-activated STAT5 (signal transducer and activator of transcription) proteins, and mutational analysis indicates that binding of STAT5 to both sites is required for IL-2 responsiveness of the enhancer. The STAT5 dimers interact to form a STAT5 tetramer. The efficiency of tetramerization depends on the relative rotational orientation of the two STAT motifs on the DNA helix. STAT5 tetramerization on enhancer mutants correlates well with the IL-2 responsiveness of these mutants. This provides strong evidence that interactions between STAT dimers binding to a pair of weak binding sites play a biological role by controlling the activity of a well characterized, complex cytokine-responsive enhancer.

Ectopic human telomerase catalytic subunit expression maintains telomere length but is not sufficient for CD8+ T lymphocyte immortalization.

Like most somatic human cells, T lymphocytes have a limited replicative life span. This phenomenon, called senescence, presents a serious barrier to clinical applications that require large numbers of Ag-specific T cells such as adoptive transfer therapy. Ectopic expression of hTERT, the human catalytic subunit of the enzyme telomerase, permits fibroblasts and endothelial cells to avoid senescence and to become immortal. In an attempt to immortalize normal human CD8(+) T lymphocytes, we infected bulk cultures or clones of these cells with a retrovirus transducing an hTERT cDNA clone. More than 90% of transduced cells expressed the transgene, and the cell populations contained high levels of telomerase activity. Measuring the content of total telomere repeats in individual cells (by flowFISH) we found that ectopic hTERT expression reversed the gradual loss of telomeric DNA observed in control populations during long term culture. Telomere length in transduced cells reached the levels observed in freshly isolated normal CD8(+) lymphocytes. Nevertheless, all hTERT-transduced populations stopped to divide at the same time as nontransduced or vector-transduced control cells. When kept in IL-2 the arrested cells remained alive. Our results indicate that hTERT may be required but is not sufficient to immortalize human T lymphocytes.

DNA binding specificity of different STAT proteins. Comparison of in vitro specificity with natural target sites.

STAT transcription factors are expressed in many cell types and bind to similar sequences. However, different STAT gene knock-outs show very distinct phenotypes. To determine whether differences between the binding specificities of STAT proteins account for these effects, we compared the sequences bound by STAT1, STAT5A, STAT5B, and STAT6. One sequence set was selected from random oligonucleotides by recombinant STAT1, STAT5A, or STAT6. For another set including many weak binding sites, we quantified the relative affinities to STAT1, STAT5A, STAT5B, and STAT6. We compared the results to the binding sites in natural STAT target genes identified by others. The experiments confirmed the similar specificity of different STAT proteins. Detailed analysis indicated that STAT5A specificity is more similar to that of STAT6 than that of STAT1, as expected from the evolutionary relationships. The preference of STAT6 for sites in which the half-palindromes (TTC) are separated by four nucleotides (N(4)) was confirmed, but analysis of weak binding sites showed that STAT6 binds fairly well to N(3) sites. As previously reported, STAT1 and STAT5 prefer N(3) sites; however, STAT5A, but not STAT1, weakly binds N(4) sites. None of the STATs bound to half-palindromes. There were no specificity differences between STAT5A and STAT5B.

Long-term effects of CO2 laser irradiation on treatment of hypersensitive dental necks: results of an in Vivo study.

OBJECTIVE: The present in vivo study was performed to examine the long-term effects of combined CO2 laser treatment and fluoridation on hypersensitive dental necks. SUMMARY BACKGROUND DATA: Attempts have been made to treat dental hypersensitivity by sealing exposed dentinal tubules, primarily using fluoride preparations, strontium chloride, and hydroxyapatite. However, these treatment methods have the disadvantage that the preparation is effective only for a limited period of time and must be applied repeatedly, at short intervals. The CO2 laser has been shown to have an excellent sealing effect on hypersensitive dentinal surfaces. METHODS: Test subjects suffering from dentinal hypersensitivity were recruited from the patients of the Department of Conservative Dentistry, School of Dentistry of the University of Vienna, Austria and treated with combined laser irradiation and fluoridation with stannous fluoride gel. The patients were followed up for a period of 18 months. In vivo examinations were supplemented by atomic absorption spectroscopy (AAS) of tiny dentin samples obtained from the dental necks 6 weeks and 18 months after laser treatment and by scanning electron microscopy (SEM). RESULTS: Compared to conventional fluoridation, combined laser irradiation and fluoridation was shown to be effective in the treatment of hypersensitive dental necks. When success was defined as complete freedom from pain, the success rate in the laser group was 96.5%. Furthermore, examinations of irradiated teeth under the scanning electron microscope still revealed complete closure of the dentinal tubules four and six months after laser treatment. AAS showed that tin was present in the samples, which indicates that combined laser treatment and fluoridation result in permanent integration of fluoride in the dentin surface. CONCLUSIONS: Based on these results, the CO2 laser can be recommended as an ideal tool for desensitization of dental necks.

Human CD8(+) T cells expressing HLA-DR and CD28 show telomerase activity and are distinct from cytolytic effector T cells.

Cycling lymphocytes may express the enzyme telomerase which is involved in maintenance of telomere length and cell proliferation potential. In CD8(+) T cells freshly isolated from peripheral blood, we found that in vivo cycling cells expressed HLA-DR. Furthermore, CD28-positive cells are known to have longer telomeres than CD28-negative T cells. Therefore we used HLA-DR- and CD28-specific antibodies to sort CD8(+) T cells and measure telomerase activity ex vivo. Relatively high levels of telomerase activity were found in HLA-DR/CD28 double-positive cells. In contrast, HLA-DR-negative and CD28-negative cells had almost no telomerase activity. In summary, HLA-DR expression correlates with proliferation, and CD28 expression with proliferative potential. We have previously identified that ex vivo cytolytic CD8(+) T cells are CD56 (NCAM) positive. Here we show that HLA-DR(+) cells were rarely CD56(+) and vice versa. This demonstrates that telomerase-expressing and cytolytic CD8(+) T cells can be separated on the basis of the cell surface markers HLA-DR and CD56. Thus, activated CD8(+) T cells specialize and exert distinct functions correlating with surface molecule expression.

Mouse interleukin-2 receptor alpha gene expression. Interleukin-1 and interleukin-2 control transcription via distinct cis-acting elements.

We have shown that interleukin-1 (IL-1) and IL-2 control IL-2 receptor alpha (IL-2R alpha) gene transcription in CD4-CD8- murine T lymphocyte precursors. Here we map the cis-acting elements that mediate interleukin responsiveness of the mouse IL-2R alpha gene using a thymic lymphoma-derived hybridoma (PC60). The transcriptional response of the IL-2R alpha gene to stimulation by IL-1 + IL-2 is biphasic. IL-1 induces a rapid, protein synthesis-independent appearance of IL-2R alpha mRNA that is blocked by inhibitors of NF-kappa B activation. It also primes cells to become IL-2 responsive and thereby prepares the second phase, in which IL-2 induces a 100-fold further increase in IL-2R alpha transcripts. Transient transfection experiments show that several elements in the promoter-proximal region of the IL-2R alpha gene contribute to IL-1 responsiveness, most importantly an NF-kappa B site conserved in the human and mouse gene. IL-2 responsiveness, on the other hand, depends on a 78-nucleotide segment 1.3 kilobases upstream of the major transcription start site. This segment functions as an IL-2-inducible enhancer and lies within a region that becomes DNase I hypersensitive in normal T cells in which IL-2R alpha expression has been induced. IL-2 responsiveness requires three distinct elements within the enhancer. Two of these are potential binding sites for STAT proteins.