Disease-associated polymorphisms in ERAP1 do not alter endoplasmic reticulum stress in patients with ankylosing spondylitis

The mechanism by which human leukocyte antigen B27 (HLA-B27) contributes to ankylosing spondylitis (AS) remains unclear. Genetic studies demonstrate that association with and interaction between polymorphisms of endoplasmic reticulum aminopeptidase 1 (ERAP1) and HLA-B27 influence the risk of AS. It has been hypothesised that ERAP1-mediated HLA-B27 misfolding increases endoplasmic reticulum (ER) stress, driving an interleukin (IL) 23-dependent, pro-inflammatory immune response. We tested the hypothesis that AS-risk ERAP1 variants increase ER-stress and concomitant pro-inflammatory cytokine production in HLA-B27 + but not HLA-B27-AS patients or controls. Forty-nine AS cases and 22 healthy controls were grouped according to HLA-B27 status and AS-associated ERAP1 rs30187 genotypes: HLA-B27 + ERAP1 risk, HLA-B27 + ERAP1 protective, HLA-B27-ERAP1 risk and HLA-B27-ERAP1 protective. Expression levels of ER-stress markers GRP78 (8 kDa glucose-regulated protein), CHOP (C/EBP-homologous protein) and inflammatory cytokines were determined in peripheral blood mononuclear cell and ileal biopsies. We found no differences in ER-stress gene expression between HLA-B27 + and HLA-B27-cases or healthy controls, or between cases or controls stratified by carriage of ERAP1 risk or protective alleles in the presence or absence of HLA-B27. No differences were observed between expression of IL17A or TNF (tumour necrosis factor) in HLA-B27 + ERAP1 risk, HLA-B27 + ERAP1 protective and HLA-B27-ERAP1 protective cases. These data demonstrate that aberrant ERAP1 activity and HLA-B27 carriage does not alter ER-stress levels in AS, suggesting that ERAP1 and HLA-B27 may influence disease susceptibility through other mechanisms. © 2015 Macmillan Publishers Limited.

ATM, RAD50 and p53 in breast cancer

Breast cancer is the most commonly occurring cancer among women, and its incidence is increasing worldwide. Positive family history is a well established risk factor for breast cancer, and it is suggested that the proportion of breast cancer that can be attributed to genetic factors may be as high as 30%. However, all the currently known breast cancer susceptibility genes are estimated to account for 20-30% of familial breast cancer, and only 5% of the total breast cancer incidence. It is thus likely that there are still other breast cancer susceptibility genes to be found. Cellular responses to DNA damage are crucial for maintaining genomic integrity and preventing the development of cancer. The genes operating in DNA damage response signaling network are thus good candidates for breast cancer susceptibility genes. The aim of this study was to evaluate the role of three DNA damage response associated genes, ATM, RAD50, and p53, in breast cancer. ATM, a gene causative for ataxia telangiectasia (A-T), has long been a strong candidate for a breast cancer susceptibility gene because of its function as a key DNA damage signal transducer. We analyzed the prevalence of known Finnish A-T related ATM mutations in large series of familial and unselected breast cancer cases from different geographical regions in Finland. Of the seven A-T related mutations, two were observed in the studied familial breast cancer patients. Additionally, a third mutation previously associated with breast cancer susceptibility was also detected. These founder mutations may be responsible for excess familial breast cancer regionally in Northern and Central Finland, but in Southern Finland our results suggest only a minor effect, if any, of any ATM genetic variants on familial breast cancer. We also screened the entire coding region of the ATM gene in 47 familial breast cancer patients from Southern Finland, and evaluated the identified variants in additional cases and controls. All the identified variants were too rare to significantly contribute to breast cancer susceptibility. However, the role of ATM in cancer development and progression was supported by the results of the immunohistochemical studies of ATM expression, as reduced ATM expression in breast carcinomas was found to correlate with tumor differentiation and hormone receptor status. Aberrant ATM expression was also a feature shared by the BRCA1/2 and the difficult-to-treat ER/PR/ERBB2-triple-negative breast carcinomas. From the clinical point of view, identification of phenotypic and genetic similarities between the BRCA1/2 and the triple-negative breast tumors could have an implication in designing novel targeted therapies to which both of these classes of breast cancer might be exceptionally sensitive. Mutations of another plausible breast cancer susceptibility gene, RAD50, were found to be very rare, and RAD50 can only be making a minor contribution to familial breast cancer predisposition in UK and Southern Finland. The Finnish founder mutation RAD50 687delT seems to be a null allele and may carry a small increased risk of breast cancer. RAD50 is not acting as a classical tumor suppressor gene, but it is possible that RAD50 haploinsufficiency is contributing to cancer. In addition to relatively rare breast cancer susceptibility alleles, common polymorphisms may also be associated with increased breast cancer risk. Furthermore, these polymorphisms may have an impact on the progression and outcome of the disease. Our results suggest no effect of the common p53 R72P polymorphism on familial breast cancer risk or breast cancer risk in the population, but R72P seems to be associated with histopathologic features of the tumors and survival of the patients; 72P homozygous genotype was an independent prognostic factor among the unselected breast cancer patients, with a two-fold increased risk of death. These results present important novel findings also with clinical significance, as codon 72 genotype could be a useful additional prognostic marker in breast cancer, especially among the subgroup of patients with wild-type p53 in their tumors.

H N.M.R. studies of protected alpha-aminoisobutyric acid containing peptides. Chemical shift nonequivalence of benzyloxycarbonyl methylene protons

The benzylic methylene protons in a large number of benzyloxycarbonyl alpha-aminoisobutyric acid (Z-Aib) containing peptides, show chemical shift nonequivalence. The magnitude of the geminal nonequivalence is correlated with the involvement of the urethane carbonyl group, in an intramolecular hydrogen bond. Studies of the model compounds Z-Aib-Aib-Ala-NHMe, and Z-Aib-Aib-Aib-Pro-OMe clearly establish the presence of intramolecular hydrogen bonds, involving the urethane CO group. In both compounds marked anisochrony of the benzylic methylene protons is demonstrated. In Z-Aib-Aib-Pro-OMe, where a 4 leads to 1 hydrogen bonded beta-turn is not possible, the benzylic-CH2-protons appear as a singlet in CDCl3 and have a very small chemical shift difference in (CD3)2SO. The observation of such nonequivalence is of value in establishing whether the amino terminal Aib-Pro beta-turn is retained in large peptide-fragments of alamethicin.

Electronic Structure and Bonding in Neutral and Dianionic Boradiphospholes: R ' BC2P2R2 (R=H, tBu, R '=H, Ph)

Classical and non-classical isomers of both neutral and dianionic BC2P2H3 species, which are isolobal to Cp+ and Cp-, are studied at both B3LYP/6-311++G(d,p) and G3B3 levels of theory. The global minimum structure given by B3LYP/6-311+ + G(d,p) for BC2P2H3 is based on a vinylcyclopropenyl-type structure, whereas BC2P2H32- has a planar aromatic cyclopentadienyl-ion-like structure. However, at the G3B3 level, there are three low-energy isomers for BC2P2H3: 1)tricyclopentane, 2) nido and 3) vinylcyclopropenyl-type structures, all within 1.7 kcal mol(-1) of each other. On the contrary, for the dianionic species the cyclic planar structure is still the minimum. In comparison to the isolobal Cp+ and HnCnP5-n+ isomers, BC2P2H3 shows a competition between pi-delocalised vinylcyclopropenyl- and cluster-type structures (nido and tricyclopentane). Substitution of H on C by tBu, and H on B by Ph, in BC2P2H3 increases the energy difference between the low-lying isomers, giving the lowest energy structure as a tricyclopentane type. Similar substitution in BC2P2H32- merely favours different positional isomers of the cyclic planar geometry, as observed in 1) isoelectronic neutral heterodiphospholes EtBu2C2P2 (E=S, Se, Te), 2) monoanionic heterophospholyl rings EtBu2C2P2 (E=P-, As-, Sb-) and 3) polyphospholyl rings anions tBu(5-n)C(n)P(5-n) (n=0-5). The principal factors that affect the stability of three-, four-, and five-membered ring and acyclic geometrical and positional isomers of neutral and dianionic BC2P2H3 isomers appear to be: 1) relative bond strengths, 2) availability of electrons for the empty 2p boron orbital and 3) steric effects of the tBu groups in the HBC(2)P(2)tBu(2) systems.

Cyclins in Breast Cancer

Breast cancer is the most common malignancy in women in Western countries. It is a heterogeneous disease with varying biological characteristics and aggressiveness. Family history is one of the strongest predisposing factors for breast cancer. The known susceptibility genes explain only around 25% of all familial breast cancers. At least part of the unknown familial aggregation may be caused by several low-penetrance variants that occur commonly in the general population. Cyclins are cell cycle-regulating proteins. Cyclin expression oscillates during the cell cycle and is under strict control. In cancer cells, cyclin expression often becomes deregulated, leading to uncontrolled cell division and proliferation, one of the hallmarks of cancer. In this study, we investigated the role of cyclins in breast cancer predisposition, pathogenesis, and tumor behavior. Cyclin A immunohistochemistry was evaluated both on traditional large sections and on tissue microarrays (TMA). The concordance of the results was good, indicating that TMA is a reliable method for studying cyclin expression in breast cancer. The expression of cyclins D1, E, and B1 was studied among 1348 invasive breast cancers on TMA. Familial BRCA1/2-mutation negative tumors had significantly more often low cyclin E and high cyclin D1 expression than BRCA1/2 related or sporadic tumors. Unique cyclin E and D1 expression patterns among familial non-BRCA1/2 breast cancers may reflect different predisposition and pathogenesis in these groups and help to differentiate mutation-positive from mutation-negative familial cancers. High cyclin E expression was associated with an aggressive breast cancer phenotype and was an independent marker of poor metastasis-free survival. High cyclin D1 was associated with high grade and high proliferation among estrogen receptor (ER)-positive but with low grade and low proliferation among ER-negative breast cancers. Among ER-positive cancers not treated with chemotherapy, high cyclin D1 showed a trend towards shorter metastasis-free survival. These results suggest that different mechanisms may drive proliferation in ER-negative and -positive breast cancers and that cyclin D1 has a particularly important role in tumorigenesis of hormone receptor-positive breast cancer. High cyclin B1 expression was associated with aggressive breast cancer features and had an independent impact on survival. The results suggest that cyclin B1 immunohistochemistry is a method that could easily be adapted for routine use and is an independent prognostic factor, adding specificity to prognostic evaluation conducted with traditional markers. A commonly occurring cyclin D1 gene polymorphism A870G was associated with increased breast cancer risk in a large material of Finnish and Canadian breast cancer patients. The interaction of the high-activity alleles of cyclin D1 gene and estrogen metabolism gene COMT conferred an even higher risk. These results show that cyclin D1 and COMT act synergistically to contribute to breast cancer progression and that individual risk for breast cancer can be altered by the combined effect of polymorphisms with low-penetrance alleles. By investigating critical cell cycle regulator protein cyclins, we revealed new aspects of breast cancer predisposition, pathogenesis, and clinical course.

CHEK2 in Breast and Colorectal Cancer

Breast and colorectal cancers, are common types of cancer, with over two million newly diagnosed cases annually worldwide. Cancer is a genetic disease and defects in DNA integrity restoring functions make a significant contribution to cancer risk. CHEK2 is a checkpoint kinase functioning as a regulator of cell cycle checkpoints, apoptosis, and DNA repair in response to DNA double-strand breaks. The aim of this study was to evaluate the role of CHEK2 in breast cancer predisposition in Finnish breast cancer families and in breast cancer risk at the population level. We were interested in the clinical and biological characteristics of the breast tumors associated with the CHEK2 germline mutations or aberrant CHEK2 protein expression and the effect on survival of patients with these CHEK2 defects. We also assessed the role of CHEK2 mutations, namely 1100delC and I157T, in colorectal cancer susceptibility in Finland. CHEK2 I157T was found to be a low-penetrance breast cancer susceptibility allele, conferring a 1.4-fold risk for carriers. Reduced or absent CHEK2 protein expression was observed in one-fifth of breast tumors from patients unselected for family history, implying that defective CHEK2 signaling contributes to tumorigenesis. Reduction in CHEK2 expression was more common in tumors with larger diameter and ER expression, but with regard to other tumor characteristics and prognosis of a patient no association was observed. Results from comparison of CHEK2 1100delC carrier tumors with noncarrier tumors were in line with the findings from the CHEK2 expression study. Tumors from CHEK2 1100delC carriers were more often of higher grade than tumors from noncarriers, and they also tended to be ER-positive more often, although generally 1100delC status does not seem to radically affect the tumor characteristics. Our results suggest that CHEK2 1100delC may not be a susceptibility allele for CRC, although a very small effect cannot be excluded. Furthermore, CHEK2 1100delC is equally frequent in HBCC (hereditary breast and colorectal cancer) phenotype families and in breast cancer families. Over 1000 CRC cases were screened for CHEK2 I157T, and a significantly higher frequency of I157T was observed among both familial and sporadic CRC cases. The relation of CHEK2 I157T with familial CRC has not been studied previously. CHEK2 I157T seems to be a susceptibility allele for both familial and sporadic CRC, conferring a 1.5-fold risk for carriers of this variant. CHEK2 I157T has been proposed to have a role as a multiple cancer susceptibility allele, which is supported by our results since we observed a trend towards higher frequency of the variant among cases with multiple primary tumors or those with a family history of cancer. During the last five years CHEK2 has established its role as an important cancer susceptibility gene. It has become apparent that CHEK2 is a low-penetrance susceptibility gene for several cancer types, significantly contributing to familial cancer risk as well as to cancer risk at the population level.

Low-temperature Er3+ emission in Ge-S-Ga glasses excited by host absorption

The photoluminescence (PL) of a series of (GeS2)(80)(Ga2S3)(20) glasses doped with different amounts of Er (0.17, 0.35, 0.52, 1.05 and 1.39 at.%) at 77 and 4.2 K has been studied. The influence of the temperature on the emission cross-section of the PL bands at -> 1540, 980 and 820 nm under host excitation has been defined. A quenching effect of the host photoluminescence has been established from the compositional dependence of the PL intensity. It has been found that the present Er3+-doped Ge-S-Ga glasses posses PL lifetime values about 3.25 ms. (C) 2007 Elsevier B.V. All rights reserved.

R&D in clean technology: A project choice model with learning

In this study, we investigate the qualitative and quantitative effects of an R&D subsidy for a clean technology and a Pigouvian tax on a dirty technology on environmental R&D when it is uncertain how long the research takes to complete. The model is formulated as an optimal stopping problem, in which the number of successes required to complete the R&D project is finite and learning about the probability of success is incorporated. We show that the optimal R&D subsidy with the consideration of learning is higher than that without it. We also find that an R&D subsidy performs better than a Pigouvian tax unless suppliers have sufficient incentives to continue cost-reduction efforts after the new technology success-fully replaces the old one. Moreover, by using a two-project model, we show that a uniform subsidy is better than a selective subsidy.

On gravitational fields of stars in f(R) gravity theories

Einstein's general relativity is a classical theory of gravitation: it is a postulate on the coupling between the four-dimensional, continuos spacetime and the matter fields in the universe, and it yields their dynamical evolution. It is believed that general relativity must be replaced by a quantum theory of gravity at least at extremely high energies of the early universe and at regions of strong curvature of spacetime, cf. black holes. Various attempts to quantize gravity, including conceptually new models such as string theory, have suggested that modification to general relativity might show up even at lower energy scales. On the other hand, also the late time acceleration of the expansion of the universe, known as the dark energy problem, might originate from new gravitational physics. Thus, although there has been no direct experimental evidence contradicting general relativity so far - on the contrary, it has passed a variety of observational tests - it is a question worth asking, why should the effective theory of gravity be of the exact form of general relativity? If general relativity is modified, how do the predictions of the theory change? Furthermore, how far can we go with the changes before we are face with contradictions with the experiments? Along with the changes, could there be new phenomena, which we could measure to find hints of the form of the quantum theory of gravity? This thesis is on a class of modified gravity theories called f(R) models, and in particular on the effects of changing the theory of gravity on stellar solutions. It is discussed how experimental constraints from the measurements in the Solar System restrict the form of f(R) theories. Moreover, it is shown that models, which do not differ from general relativity at the weak field scale of the Solar System, can produce very different predictions for dense stars like neutron stars. Due to the nature of f(R) models, the role of independent connection of the spacetime is emphasized throughout the thesis.

Existence of multiple positive solutions for N-laplacian in a bounded domain in R-N

Let Ohm be a bounded domain in IRN, N greater than or equal to 2, lambda > 0, q is an element of (0, N - 1) and alpha is an element of (1, N/N-1 In this article we show the existence of at least two positive solutions for the following quasilinear elliptic problem with an exponential type nonlinearity:

Morphogenesis of Mammalian Endoplasmic Reticulum and Golgi Apparatus throughout the Cell Cycle

The endoplasmic reticulum (ER) and the Golgi apparatus are organelles that produce, modify and transport proteins and lipids and regulate Ca2+ environment within cells. Structurally they are composed of sheets and tubules. Sheets may take various forms: intact, fenestrated, single or stacked. The ER, including the nuclear envelope, is a single continuous network, while the Golgi shows only some level of connectivity. It is often unclear, how different morphologies correspond to particular functions. Previous studies indicate that the structures of the ER and Golgi are dynamic and regulated by fusion and fission events, cytoskeleton, rate of protein synthesis and secretion, and specific structural proteins. For example, many structural proteins shaping tubular ER have been identified, but sheet formation is much more unclear. In this study, we used light and electron microscopy to study morphological changes of the ER and Golgi in mammalian cells. The proportion, type, location and dynamics of ER sheets and tubules were found to vary in a cell type or cell cycle stage dependent manner. During interphase, ER and Golgi structures were demonstrated to be regulated by p37, a cofactor of the fusion factor p97, and microtubules, which also affected the localization of the organelles. Like previously shown for the Golgi, the ER displayed a tendency for fenestration and tubulation during mitosis. However, this shape change did not result in ER fragmentation as happens to Golgi, but a continuous network was retained. The activity of p97/p37 was found to be important for the reassembly of both organelles after mitosis. In EM images, ER sheet membranes appear rough, since they contain attached ribosomes, whereas tubular membranes appear smooth. Our studies revealed that structural changes of the ER towards fenestrated and tubular direction correlate with loss of ER-bound ribosomes and vice versa. High and low curvature ER membranes have a low and high density of ribosomes, respectively. To conclude, both ER and Golgi architecture depend on fusion activity of p97/p37. ER morphogenesis, particularly of the sheet shape, is intimately linked to the density of membrane bound ribosomes.

Creep behaviour of nimonic and R.R. 59 alloys

The Ramberg-Osgood relation which adequately describes the stress-strain curve of a strain-hardening material is extended to formulate the constitutive laws for creep. The constitutive laws which describe primary creep adequately are extended to secondary creep. The results are verified for the case of R.R. 59 at 200°C, Nimonic 80A and Nimonic 90 alloys at 750°C.