A colorectal cancer susceptibility new variant at 4q26 in the Spanish population identified by genome-wide association analysis.

BACKGROUND: Non-hereditary colorectal cancer (CRC) is a complex disorder resulting from the combination of genetic and non-genetic factors. Genome-wide association studies (GWAS) are useful for identifying such genetic susceptibility factors. However, the single loci so far associated with CRC only represent a fraction of the genetic risk for CRC development in the general population. Therefore, many other genetic risk variants alone and in combination must still remain to be discovered. The aim of this work was to search for genetic risk factors for CRC, by performing single-locus and two-locus GWAS in the Spanish population. RESULTS: A total of 801 controls and 500 CRC cases were included in the discovery GWAS dataset. 77 single nucleotide polymorphisms (SNP)s from single-locus and 243 SNPs from two-locus association analyses were selected for replication in 423 additional CRC cases and 1382 controls. In the meta-analysis, one SNP, rs3987 at 4q26, reached GWAS significant p-value (p = 4.02×10(-8)), and one SNP pair, rs1100508 CG and rs8111948 AA, showed a trend for two-locus association (p = 4.35×10(-11)). Additionally, our GWAS confirmed the previously reported association with CRC of five SNPs located at 3q36.2 (rs10936599), 8q24 (rs10505477), 8q24.21(rs6983267), 11q13.4 (rs3824999) and 14q22.2 (rs4444235). CONCLUSIONS: Our GWAS for CRC patients from Spain confirmed some previously reported associations for CRC and yielded a novel candidate risk SNP, located at 4q26. Epistasis analyses also yielded several novel candidate susceptibility pairs that need to be validated in independent analyses.

C4d as a diagnostic tool in membranous nephropathy.

INTRODUCTION: membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults. The diagnosis is based on typical findings observed using electron microscope (EM) and immunofluorescence (IF) studies. On some occasions, tissues are only available for analysis using an optical microscope (OM); in these cases, it can be difficult to differentiate between MN and minimal change disease (MCD). Recently, the use of C4d immunohistochemical staining has spread. Very little information is available regarding C4d deposits in MN. Our study consisted of analysing whether C4d staining of samples embedded in paraffin could be useful for diagnosing MN. MATERIAL AND METHOD: Ours was a retrospective study including all patients diagnosed with MN by renal biopsy in our unit between January 2001 and October 2008. We only included adult patients with a definitive diagnosis of MN or idiopathic MCD by OM, IF, and ME studies. In October 2008, 3µm sections of renal tissue fixed in formaldehyde were removed from paraffin and rehydrated. The samples were then stained for C4d immunohistochemical analysis using anti-human polyclonal antibodies obtained from rabbits. RESULTS: Our study included a final sample of 19 patients with MCD and 21 with MN. No C4d deposits were observed in any of the glomeruli in patients with MCD, and 100% of these patients were classified as negative. However, C4d deposits were detected in 100% of patients with MN, and were observable in all glomeruli with a uniform granular distribution, demarcating all capillary loops. CONCLUSIONS: C4d immunohistochemical staining is a very useful tool for diagnosing MN.

Acute toxicity and bioconcentration of fungicide tebuconazole in zebrafish (Danio rerio).

This research work investigated the bioconcentration of tebuconazole [(±)-α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol] fungicide in zebrafish (Danio rerio) under laboratory conditions and a first-order kinetic pesticide dissipation in the water. The concentrations of tebuconazole fitted to an equivalent nonlinear kinetic type model which allowed the calculation of the following parameters: bioconcentration factor (38.80 L kg(-1) ), time to reach maximum fish concentration (6 days), maximum concentration in fish (0.0075 µg mg(-1) ), half-life in fish (24 days) and time needed for the fish to eliminate 95% of the maximum concentration (105 days). These calculations permitted the establishment of theoretical reference limit values for human consumption of fish and the establishment of safe limits for the water pesticide concentration. The data would also be useful in safe strategies associated with fishery activities that are conducted in aquatic regions close to crops using tebuconazole. The information will contribute to enlarge the tebuconazole toxicokinetics database of aquatic organisms.

Genetic structure of the Spanish population.

BACKGROUND: Genetic admixture is a common caveat for genetic association analysis. Therefore, it is important to characterize the genetic structure of the population under study to control for this kind of potential bias. RESULTS: In this study we have sampled over 800 unrelated individuals from the population of Spain, and have genotyped them with a genome-wide coverage. We have carried out linkage disequilibrium, haplotype, population structure and copy-number variation (CNV) analyses, and have compared these estimates of the Spanish population with existing data from similar efforts. CONCLUSIONS: In general, the Spanish population is similar to the Western and Northern Europeans, but has a more diverse haplotypic structure. Moreover, the Spanish population is also largely homogeneous within itself, although patterns of micro-structure may be able to predict locations of origin from distant regions. Finally, we also present the first characterization of a CNV map of the Spanish population. These results and original data are made available to the scientific community.

CALHM1 P86L polymorphism is associated with late-onset Alzheimer's disease in a recessive model.

CALHM1 gene coding non-synonymous SNP P86L (rs2986017) was reported to increase the risk of Alzheimer's disease (AD) in a recent study. We have investigated this genetic variant in 2470 individuals from Spain to conduct an independent replication study of the proposed SNP marker. By applying a recessive model, we observed weak evidence of an association between P86L mutation and late-onset AD (LOAD) susceptibility in our case-control study (OR =1.38 C.I. = [1.01-1.89]). Meta-analysis of available studies also supports a recessive model for CALHM1 P86L variant and provides evidence of between study heterogeneity. Importantly, we found that adjusted mean age at AD onset in P86L homozygous LOAD patients was significantly earlier that in the rest of patients (77.01 +/- 6.1 for P86L homozygous carriers versus 79.0 +/- 6.0 for the rest of patients, p=0.002). We concluded that the CALMH1 gene may contribute to AD risk in our study population. The observed genetic model (recessive) and the estimated magnitude of the effect both imply that virtually all studies performed to date were markedly underpowered to detect this effect and underscore the importance of follow up, replication, and meta-analyses of promising genetic signals.

Fusarin C Production by Fusarium spp. from Spain.

From 657 samples of grains and feedstuffs (1991 to 1992 and 1992 to 1993 surveys), collected in two different geographical areas of Spain, 154 isolates of Fusarium spp. were obtained. The isolates were screened for their ability to produce fusarin C in a modified 10% ICI N synthetic liquid medium. The production of fusarin C was verified by means of spectrophotometry, thin layer chromatography, high-performance liquid chromatography, and nuclear magnetic resonance. Results showed that more than 57% of tested isolates were able to produce fusarin C at levels of 0.04 to 200 µg/liter of ICI medium. There were no statistically significant differences (P < 0.05) between levels of fusarin C production and the geographical origin of the Fusarium isolates. The Fusarium isolates that produced fusarin C were identified as F. moniliforme , F. oxysporum , F. sporotrichioides , and F. poae . This is the first report of fusarin C production by F. oxysporum .

Relationship between the Stages of Development of Fusarium moniliforme ATCC 38932 and Production of Fusarin C.

A study of the kinetics of fusarin C production by Fusarium moniliforme ATCC 38932, a known producer of fusarin C, was carried out. This strain was subcultured on an EG medium for an adequate sporulation, and a 4% inoculum was transferred to the 10% ICI N medium. The conditions for the production of fusarin C in this synthetic culture medium were optimized. The time-course study of fusarin C performed over 26 days with this strain showed three different developmental stages in which a maximum production of fusarin C was reached on the 8th day of incubation; thereafter this strain ceased growing exponentially and exhibited a sharp decrease of fusarin C from that moment on.