Channelrhodopsin-2 (ChR2) is a member of the new class of light-gated ion channels which serve as phototaxis receptors in the green alga Chlamydomonas reinhardtii. The protein is employed in optogenetics where neural circuits are optically stimulated under high spatiotemporal control. Despite its rapidly growing use in physiological experiments, the reaction mechanism of ChR2 is poorly understood.
View Article and Find Full Text PDFInt Arch Allergy Immunol
July 2009
Background: There is evidence for an association between serum cholesterol concentrations and asthma, but little is known about the underlying mechanisms. We explored the associations between serum apolipoprotein concentrations and symptoms of asthma and atopy.
Methods: In a population-based cross-sectional study among 10-year-old schoolchildren (n = 462), plasma concentrations of apolipoprotein AI (apoAI) and apolipoprotein B (apoB) were measured.
There is still a debate about the role of body mass index (BMI) as a risk factor for all-cause mortality. Most investigations with large sample sizes focused on populations from the United States, studies from Central-European cohorts are not available. We investigated the association between BMI and all-cause mortality and cause-specific mortality within a cohort in Austria.
View Article and Find Full Text PDFThe association between breastfeeding and wheezing, lung function and atopy was evaluated in the International Study of Asthma and Allergy in Childhood (ISAAC) Phase II. Cross-sectional studies were performed in 27 centres in 20 countries. Information on disease and exposure factors was collected by parental questionnaires.
View Article and Find Full Text PDFBackground: In aging populations, the prevalence of multimorbidity is high, and the role of socioeconomic status and its correlates is not well described. Thus, we investigated the association between educational attainment and multimorbidity in a prospective cohort study, taking also into account intermediate factors that could explain such associations.
Methods: We included 13,781 participants of the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC), who were 50-75 years at the end of follow-up.
Background: Several studies have consistently reported inverse associations between exposure to endotoxin in house dust and atopy. With regard to the association between house dust endotoxin and asthma, the results are inconsistent.
Objectives: To study the association between house dust endotoxin levels and respiratory symptoms and atopy in populations from largely different countries.
Background: The contribution of genetic variation in DNA repair genes to gastric cancer (GC) risk remains essentially unknown. The aim of this study was to explore the relative contribution of DNA repair gene polymorphisms to GC risk and severe chronic atrophic gastritis (SCAG). Method A nested case control study within the EPIC cohort was performed including 246 gastric adenocarcinomas and 1175 matched controls.
View Article and Find Full Text PDFThe metabotropic glutamate receptor 7a (mGluR7a), a heptahelical Galphai/o-coupled protein, has been shown to be important for presynaptic feedback inhibition at central synapses and certain forms of long term potentiation and long term depression. The intracellular C terminus of mGluR7a interacts with calmodulin in a Ca2+-dependent manner, and calmodulin antagonists have been found to abolish presynaptic inhibition of glutamate release in neurons and mGluR7a-induced activation of G-protein-activated inwardly rectifying K+ channel (GIRK) channels in HEK293 cells. Here, we characterized the Ca2+ dependence of mGluR7a signaling in Xenopus oocytes by using channelrhodopsin-2 (ChR2), a Ca2+-permeable, light-activated ion channel for triggering Ca2+ influx, and a GIRK3.
View Article and Find Full Text PDFUveal melanoma is associated with a high mortality rate once metastases occur, with over >90% of metastatic patients dying within less than 1 year from metastases to the liver. The intraarterial hepatic (iah) administration of the alkylating agent fotemustine holds some promise with response rates of 36% and median survival of 15 months. Here, we investigated whether the DNA-repair-protein MGMT may be involved in the variability of response to fotemustine and temozolomide in uveal melanoma.
View Article and Find Full Text PDFBackground/aims: The causes of ulcerative colitis are unknown, although it is plausible that dietary factors are involved. Case-control studies of diet and ulcerative colitis are subject to recall biases. The aim of this study was to examine the prospective relationship between the intake of nutrients and the development of ulcerative colitis in a cohort study.
View Article and Find Full Text PDFPediatr Allergy Immunol
February 2009
There is growing evidence for an association between obesity and asthma, but little is known about the underlying mechanisms. We hypothesized that high plasma leptin and low plasma adiponectin concentrations might be related to asthma and allergies in children. Plasma leptin and adiponectin concentrations were measured in a cross-sectional study involving 462 children aged 10 years.
View Article and Find Full Text PDFBackground: Obesity is associated with substantial metabolic changes and subclinical inflammation. We explored associations between body mass index (BMI) and cardiometabolic biomarkers and their clustering in overweight and obese schoolchildren.
Methods: In this population-based, cross-sectional study among 450 children 10 years old, we measured adiponectin, leptin, inflammatory markers, apolipoprotein (apo) AI and B, and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)).
In 2003, channelrhodopsin-2 (ChR2) from Chlamydomonas reinhardtii was discovered to be a light-gated cation channel, and since that time the channel became an excellent tool to control by light neuronal cells in culture as well as in living animals with high temporal and spatial resolution in a noninvasive manner. However, little is known about the spectral properties and their relation to the channel function. We have expressed ChR2 in the yeast Pichia pastoris and purified the protein.
View Article and Find Full Text PDFThe DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) plays a pivotal role in alkylating drug resistance. Here, we determined MGMT activity in primary and recurrent glioblastomas (GBM, WHO grade IV) of patients who received radiation therapy (RT) or RT plus chemotherapy with alkylating agents (temozolomide, chloroethylnitrosoureas). The mean MGMT activity of untreated GBM was 37 +/- 45 (range 0-205) fmol/mg proteins.
View Article and Find Full Text PDFActivation of c-Jun, a major component of the AP-1 transcription factor, represents a paradigm for transcriptional response to stress. Transactivation of c-Jun is regulated by Jun-N-terminal kinases (JNKs) through phosphorylation at serine 63 and 73 (S63/S73), as well as at threonine 91 and 93 (T91/T93). How these two groups of phosphoacceptor sites respond to different grades of genotoxic stress and whether DNA-damage pathways influence the extent of their JNK-dependent phosphorylations remain to be elucidated.
View Article and Find Full Text PDFOur understanding of the cellular implementation of systems-level neural processes like action, thought and emotion has been limited by the availability of tools to interrogate specific classes of neural cells within intact, living brain tissue. Here we identify and develop an archaeal light-driven chloride pump (NpHR) from Natronomonas pharaonis for temporally precise optical inhibition of neural activity. NpHR allows either knockout of single action potentials, or sustained blockade of spiking.
View Article and Find Full Text PDFObjective: To investigate the association of a posteriori dietary patterns with overall survival of older Europeans.
Design And Setting: This is a multi-centre cohort study. Cox regression analysis was used to investigate the association of the prevailing, a posteriori-derived, plant-based dietary pattern with all-cause mortality in a population of subjects who were 60 years or older at recruitment to the European Prospective Investigation into Cancer and Nutrition (EPIC-Elderly cohort).
Within a prospective cohort study, we explored the long-term reproducibility of the food-frequency questionnaire (FFQ) and dietary changes in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort. After a mean follow-up time of 68.8 (sd 4.
View Article and Find Full Text PDFObjective: Most epidemiologic studies have suggested an increased risk of breast cancer with increasing alcohol intake. Using data from 274,688 women participating in the European Prospective Investigation into Cancer and Nutrition study (EPIC), we investigated the relation between alcohol intake and the risk of breast cancer.
Methods: Incidence rate ratios (IRRs) based on Cox proportional hazard models were calculated using reported intake of alcohol, recent (at baseline) and lifetime exposure.
Objectives: To evaluate the association of socioeconomic position with adenocarcinoma of the oesophagus and stomach.
Methods: The European Prospective Investigation into Cancer and Nutrition (EPIC) cohort comprises about 520 000 participants mostly aged 35-70 years. Information on diet and lifestyle was collected at recruitment.
The expression expert patient appeared about ten years ago. It defines the role of patients who are actively involved in their disease management. Most clinical oncologists are challenged by expert patients.
View Article and Find Full Text PDFObjective: To describe the prevalence and to assess type and indicators of hormone replacement therapy (HRT) use in the two German EPIC-cohorts.
Methods: Approximately 30,000 women predominantly aged 35-65 years were recruited in EPIC-Heidelberg and EPIC-Potsdam between 1994 and 1998. Information on diet and lifestyle, medical history and use of hormone therapy was collected at recruitment.
Metabolizing enzymes, which often display genetic polymorphisms, are involved in the activation of compounds present in tobacco smoke that may be relevant to gastric carcinogenesis. We report the results of a study looking at the association between risk of gastric adenocarcinoma and polymorphisms in genes CYP1A1, CYP1A2, EPHX1, and GSTT1. A nested case-control study was carried out within the European Prospective Investigation into Cancer and Nutrition, developed in 10 European countries.
View Article and Find Full Text PDFSalmonella meningitis is an unusual complication of Salmonella sepsis and occurs mainly in children. A rare case of Salmonella typhimurium meningitis occurring in an adult HIV positive man who presented with a history of fever and diarrhoea is reported. On examination he was dehydrated, and had oral thrush, weakness of lower limbs and neck stiffness.
View Article and Find Full Text PDFHelicobacter pylori (H. pylori), atrophic gastritis, dietary and life-style factors have been associated with gastric cancer (GC). These factors have been evaluated in a large case-control study nested in the European Prospective Investigation into Cancer and Nutrition carried out in 9 countries, including the Mediterranean area.
View Article and Find Full Text PDF