The level of claudin-7 is reduced as an early event in colorectal carcinogenesis

<p>Abstract</p> <p>Background</p> <p>Compromised epithelial barriers are found in dysplastic tissue of the gastrointestinal tract. Claudins are transmembrane proteins important for tight junctions. Claudins regulate the paracellular transport and are crucial for maintaining a functional epithelial barrier. Down-regulation of the oncogenic serine protease, matriptase, induces leakiness in epithelial barriers both <it>in vivo </it>and <it>in vitro</it>. We found in an <it>in-silico </it>search tight co-regulation between <it>matriptase </it>and <it>claudin-7 </it>expression. We have previously shown that the <it>matriptase </it>expression level decreases during colorectal carcinogenesis. In the present study we investigated whether <it>claudin-7 </it>expression is likewise decreased during colorectal carcinogenesis, thereby causing or contributing to the compromised epithelial leakiness of dysplastic tissue.</p> <p>Methods</p> <p>The mRNA level of <it>claudin-7 </it>(CLDN7) was determined in samples from 18 healthy individuals, 100 individuals with dysplasia and 121 colorectal cancer patients using quantitative real time RT-PCR. In addition, immunohistochemical stainings were performed on colorectal adenomas and carcinomas, to confirm the mRNA findings.</p> <p>Results</p> <p>A 2.7-fold reduction in the <it>claudin-7 </it>mRNA level was found when comparing the biopsies from healthy individuals with the biopsies of carcinomas (p < 0.001). Reductions in the <it>claudin-7 </it>mRNA levels were also detected in mild/moderate dysplasia (p < 0.001), severe dysplasia (p < 0.01) and carcinomas (p < 0.01), compared to a control sample from the same individual. The decrease at mRNA level was confirmed at the protein level by immunohistochemical stainings.</p> <p>Conclusions</p> <p>Our results show that the <it>claudin-7 </it>mRNA level is decreased already as an early event in colorectal carcinogenesis, probably contributing to the compromised epithelial barrier in adenomas.</p

Perception of Thermal Pain and the Thermal Grill Illusion Is Associated with Polymorphisms in the Serotonin Transporter Gene

AIM: The main aim of this study was to assess if the perception of thermal pain thresholds is associated with genetically inferred levels of expression of the 5-HT transporter (5-HTT). Additionally, the perception of the so-called thermal grill illusion (TGI) was assessed. Forty-four healthy individuals (27 females, 17 males) were selected a-priori based on their 5-HTTLPR/rs25531 ('tri-allelic 5-HTTLPR') genotype, with inferred high or low 5-HTT expression. Thresholds for heat- and cold-pain were determined along with the sensory and affective dimensions of the TGI. RESULTS: Thresholds to heat- and cold-pain correlated strongly (rho  = -0.58, p<0.001). Individuals in the low 5-HTT-expressing group were significantly less sensitive to heat-pain (p = 0.02) and cold-pain (p = 0.03), compared to the high-expressing group. A significant gender-by-genotype interaction also emerged for cold-pain perception (p = 0.02); low 5-HTT-expressing females were less sensitive. The TGI was rated as significantly more unpleasant (affective-motivational dimension) than painful (sensory-discriminatory dimension), (p<0.001). Females in the low 5-HTT expressing group rated the TGI as significantly less unpleasant than high 5-HTT expressing females (p<0.05), with no such differences among men. CONCLUSION/SIGNIFICANCE: We demonstrate an association between inferred low 5-HTT expression and elevated thresholds to thermal pain in healthy non-depressed individuals. Despite the fact that reduced 5-HTT expression is a risk factor for chronic pain we found it to be related to hypoalgesia for threshold thermal pain. Low 5-HTT expression is, however, also a risk factor for depression where thermal insensitivity is often seen. Our results may thus contribute to a better understanding of the molecular underpinnings of such paradoxical hypoalgesia. The results point to a differential regulation of thermoafferent-information along the neuraxis on the basis of 5-HTT expression and gender. The TGI, suggested to rely on the central integration of thermoafferent-information, may prove a valuable tool in probing the affective-motivational dimension of these putative mechanisms

Alterations of the fragile histidine triad gene, FHIT, and its encoded products contribute to testicular germ cell tumorigenesis

The fragile histidine triad (FHIT) gene, located within chromosome arm 3p, is a potential target for testicular tumorigenesis. In the present study, 62 primary testicular germ cell tumors were analyzed for allelic imbalance (AI) at 10 loci mapping to chromosome bands 3p14.1-21.1. Twenty-seven tumors (44%) showed AI at one or more 3p loci. The chromosome 3 copy number was evaluated by fluorescence in situ hybridization with centromere and p-telomere probes onto interphase nuclei from 22 of the tumors. Sixteen of these (73%) presented three or more signals of each probe in at least one-third of the nuclei. The combined fluorescence in situ hybridization and AI results indicated that tumors with AI at all loci, in most cases (five of six), reflected an increased chromosome copy number, whereas tumors presenting AI only at some loci reflected interstitial chromosomal changes. A smallest region of overlapping changes could be delineated from tumors showing interstitial chromosomal changes (n = 16). The smallest region of overlapping changes was flanked by D3S1312 and D3S1234 and included parts of FHIT. In the second part of this study, expression analyses of FHIT were performed. Transcripts of aberrant lengths were found in 7 of 17 (41%) analyzed tumors and were identified by sequencing as splice variants. Three different types of transcripts were found, and all lacked exon 3. Immunohistochemical staining showed reduced Fhit protein expression, compared with normal testicular tissue, in 62% (40 of 65) of the testicular germ cell tumors. Although we found a significant association between FHIT mRNA alterations and AI (P = 0.006), altered protein expression did not correlate with AI. The nonepithelial components of teratomas showed strong association with reduced Fhit protein compared with the epithelial component (P < 0.001). Interestingly, reduced Fhit expression seems to be associated with metastasis in the patient at the time of diagnosis, although the association was not statistically significant

On obtaining optimal well rates and placement for CO2 storage

Large-scale storage of CO2 in saline aquifers is considered an essential technology to mitigate CO2 emissions. Storage potential has mainly been estimated based on volumetrics or detailed simulations for specific injection scenarios. In practice, achievable storage capacity will depend on engineering, economical, and political restrictions and be limited by the length of the injection period, costs associated with potential CO2 leakage, pressure management, etc. We show how achievable storage volumes can be estimated and maximized using adjoint-based optimization and a hierarchy of simulation methods. In particular, vertical equilibrium models provide the simplest possible description of the flow dynamics during the injection and early post-injection period, while percolation type methods provide effective means for forecasting the long-term fate of CO2 during the later migration stages. We investigate the storage volumes that can be achieved for several formations found along the Norwegian Continental Shelf by optimizing well placement and injection rates, and using production wells for pressure management when necessary. Optimal strategies are obtained under various objectives and simple but realistic constraints, namely: penalization of CO2 leakage, minimization of well cost, and restriction of pressure buildup.acceptedVersio