Actigraphic sleep fragmentation,efficiency and duration associate with dietary intake in the Rotterdam Study

Short self‐reported sleep duration is associated with dietary intake and this association may partly mediate the link between short sleep and metabolic abnormalities. Subjective sleep measures, however, may be inaccurate and biased. The objective of this study was to evaluate the associations between actigraphic measures of sleep fragmentation, efficiency and duration and energy and macronutrient intakes. We used data from a subgroup of 439 participants of the population‐based cohort, Rotterdam Study. Sleep was assessed using 7‐day actigraphy and sleep diaries, and dietary data with a validated food frequency questionnaire. We assessed the associations of actigraphic sleep parameters with dietary intake using multivariable linear regression models. Higher sleep fragmentation was associated with 4.19 g lower carbohydrate intake per standard deviation of fragmentation {β [95% confidence interval (CI) = ?4.19 (?8.0, ?0.3)]; P = 0.03}. Each additional percentage increase in sleep efficiency was associated with 11.1 kcal lower energy intake [β (95% CI) = ?11.1 (?20.6, ?1.7); P = 0.02]. Furthermore, very short sleep duration (<5.5 h) was associated with 218.1 kcal higher energy intake [β (95% CI = 218.06 (33.3, 402.8), P = 0.02], relative to the reference group (≥6.5 to <7.5 h). We observed associations between higher sleep fragmentation with lower carbohydrate intake, and both lower sleep efficiency and very short sleep duration (<5 h) with higher energy intake. The association between sleep and higher energy intake could mediate, in part, the link between short sleep or sleep fragmentation index and metabolic abnormalities.     

Correlation of FCGR3A and EGFR germline polymorphisms with the efficacy of cetuximab in KRAS wild-type metastatic colorectal cancer

BackgroundNext to KRAS mutation status, additional predictive markers are needed for the response to cetuximab in patients with metastatic colorectal cancer (mCRC). Previous studies indicated that germline polymorphisms in specific genes may predict efficacy and toxicity of cetuximab in mCRC patients.MethodsGermline DNA was isolated from 246 KRAS wild-type mCRC patients who were treated in the phase III CAIRO2 study with chemotherapy and bevacizumab alone or with the addition of cetuximab. Associations of epidermal growth factor (EGF) 61A > G, EGF receptor (EGFR) CA_14–22, cyclin D1 (CCND1) 932G > A, fragment-C gamma receptor (FCGR) 2A 535A > G and FCGR3A 818A > C polymorphisms with progression-free survival (PFS) and cetuximab-related skin toxicity were studied.ResultsIn cetuximab-treated patients, the FCGR3A 818C-allele was associated with decreased PFS compared with the FCGR3A 818AA genotype (median PFS, 8.2 [95%CI, 6.7–10.3] versus 12.8 [95%CI, 10.3–14.7] months, respectively; HR, 1.57 [95%CI, 1.06–2.34]; P = .025). The EGFR ? 20 genotype was associated with decreased PFS compared with the EGFR < 20 genotype (median PFS, 7.6 [95%CI, 6.7–10.0] versus 12.4 [95%CI, 10.3–13.4] months, respectively; HR, 1.58 [95%CI, 1.06–2.35]; P = .024). The FCGR3A and EGFR polymorphisms were not associated with PFS in patients treated without cetuximab. None of the polymorphisms were associated with the incidence of grades 2–3 skin toxicity.ConclusionEGFR and FCGR3A germline polymorphisms are associated with PFS in KRAS wild-type mCRC patients treated with cetuximab, bevacizumab and chemotherapy.     

Quality of the parent-child interaction in young children with type 1 diabetes mellitus: study protocol

Background  

In young children with type 1 diabetes mellitus (T1DM) parents have full responsibility for the diabetes-management of their child (e.g. blood glucose monitoring, and administering insulin). Behavioral tasks in childhood, such as developing autonomy, and oppositional behavior (e.g. refusing food) may interfere with the diabetes-management to achieve an optimal blood glucose control. Furthermore, higher blood glucose levels are related to more behavioral problems. So parents might need to negotiate with their child on the diabetes-management to avoid this direct negative effect. This interference, the negotiations, and the parent's responsibility for diabetes may negatively affect the quality of parent-child interaction. Nevertheless, there is little knowledge about the quality of interaction between parents and young children with T1DM, and the possible impact this may have on glycemic control and psychosocial functioning of the child. While widely used global parent-child interaction observational methods are available, there is a need for an observational tool specifically tailored to the interaction patterns of parents and children with T1DM. The main aim of this study is to construct a disease-specific observational method to assess diabetes-specific parent-child interaction. Additional aim is to explore whether the quality of parent-child interactions is associated with the glycemic control, and psychosocial functioning (resilience, behavioral problems, and quality of life).     

CYP2D6 genotype in relation to hot flashes as tamoxifen side effect in a Dutch cohort of the tamoxifen exemestane adjuvant multinational (TEAM) trial

In tamoxifen-treated breast cancer patients the occurrence of hot flashes may be associated with effective estrogen receptor antagonism dependent on genetic variations of metabolic enzymes and the estrogen receptor. Early breast cancer patients who were randomized to receive tamoxifen, followed by exemestane within the tamoxifen exemestane adjuvant multinational trial were genotyped for five CYP2D6 alleles. CYP2D6 genotypes and phenotypes were related to the occurrence of hot flashes as adverse event during the first year of tamoxifen use (primary aim) and the time to the occurrence of hot flashes as AE during the complete time on tamoxifen (secondary aim). In addition, exploratory analyses on 22 genetic variants of other metabolic enzymes and two common polymorphisms in the estrogen receptor-1 were performed. No association was found between the CYP2D6 genotype/phenotype or any other genetic variant and hot flashes during the first year. Only higher age was related to a lower incidence of hot flashes in the first year (adjusted odds ratio 0.94, 95 % CI 0.92–0.96; p < 0.001). The ESR1 PvuII XbaI CG haplotype was associated with the time to the occurrence of hot flashes during the complete time on tamoxifen (CG/CG vs. CG/other + other/other: adjusted hazard ratio 0.49, 95 % CI 0.25–0.97; p = 0.04). In conclusion, the CYP2D6 genotypes and phenotypes were not associated with the occurrence of hot flashes. Common polymorphisms in the estrogen receptor-1 might predict hot flashes as common tamoxifen side effect, although this finding needs replication.     

Genotyping of DNA Samples Isolated from Formalin-Fixed Paraffin-Embedded Tissues Using Preamplification

DNA isolated from formalin-fixed paraffin-embedded (FFPE) tissue is often fragmented and cross-linked and is therefore difficult to genotype. To enable this source of DNA for genotyping analysis using Taqman probes, we tested whether enrichment of the target genes would increase the amount of available DNA. For enrichment of the target genes, we used preamplification by means of diluted Taqman assays. To establish the appropriateness of preamplification, we used DNA extracted from paraffin-embedded tissue and compared the genotyping results of a series of single nucleotide polymorphisms assessed in DNA samples with and without preamplification. In a subset of patients, DNA was isolated from both blood and FFPE tissue to test the reliability of genotyping results derived after preamplification. We found an increase in call rate after preamplification and a convincing concordance in genotype. Based on our findings, we can safely conclude that preamplification of DNA isolated from paraffin-embedded tissue is a valuable and reliable method to optimize genotyping results.For most genotyping assays, high-quality DNA is preferred to guarantee reliable and reproducible results.¹ DNA is preferably isolated from EDTA anticoagulated blood, because heparin may interfere in the polymerase chain reaction (PCR).² For diagnostic testing, it is usually not a problem to obtain fresh blood, although in neonates cheek swabs may be preferred. However, if fresh EDTA anticoagulated blood is not available, for instance in retrospective studies, archived biological samples may also have to be used. Archived biological samples may consist of frozen EDTA anticoagulated blood, serum/plasma or formalin fixed paraffin embedded (FFPE) tissue, however the DNA yield and quality from such sources may be poor (reviewed in Ref. ³). Consequently, the success rate of genotyping DNA purified from such samples is low. Due to formalin fixation, DNA isolated from FFPE tissue, is cross linked and therefore difficult to amplify by PCR.^4,5 In addition, such DNA is fragmented into pieces with a length of a few hundred bp.⁶ Because this fragmentation is random, it is difficult, if not impossible, to predict whether the target sequence can be efficiently amplified.To make DNA isolated from FFPE tissue more suitable for genotyping studies, we tested the feasibility of a preamplification step using single nucleotide polymorphisms (SNP)-specific Taqman assays. The preamplification step was used to enrich for sequences around target SNPs and consisted of a PCR reaction containing all Taqman assays (diluted) in one single tube per sample. This step was performed before Taqman analysis. The preamplification procedure was originally developed to genotype small amounts of complementary DNA (reverse transcribed RNA) and has successfully been used in expression studies⁷ but also in genotyping trace amounts of DNA isolated from plasma or dried blood.⁸ We compared the results obtained with and without the preamplification step on DNA isolated from FFPE tissue. For a subset of samples, we were able to compare genotypes in DNA derived from blood and FFPE tissue. In addition, we tested whether preamplification affects the results through abundance of one allele in genes with copy number variants (CNV). To our knowledge, this is the first report describing successful genotyping of DNA derived from FFPE tissue using SNP specific preamplification, making FFPE tissue an interesting source for large retrospective genetic or pharmacogenetic studies.     

Cystine dimethylester model of cystinosis: still reliable?

The ability of cystine dimethylester (CDME) to load lysosomes with cystine has been used to establish the basic defect in cystinosis: defective cystine exodus from lysosomes. Using CDME loading, it has been postulated that cystine accumulation in cystinosis affects mitochondrial ATP production, resulting in defective renal tubular reabsorption. Recent studies in cystinotic fibroblasts, however, show normal adenosine triphosphate (ATP) generation capacity. To investigate the effect of CDME in more detail, mitochondrial ATP generation, reactive oxygen species production, and viability are compared in fibroblasts loaded with CDME with those of cystinotic cells with a defective cystine transporter. Intracellular cystine levels were comparable in fibroblasts loaded with CDME (1 mM, 30 min) and cystinotic fibroblasts. Intracellular ATP levels and mitochondrial ATP production were decreased in fibroblasts loaded with CDME, but normal in cystinotic fibroblasts. Superoxide production was increased with 300% after CDME loading, whereas no changes were observed in cystinotic fibroblasts. Exposure to CDME led to cell death in a time- and concentration-dependent manner. Our data demonstrate that CDME has a toxic effect on mitochondrial ATP production and cell viability. These effects are not observed in cystinotic cells, indicating that a more appropriate model is required for studying the pathogenesis of cystinosis.