Publications

This paper describes a portable, three-dimensional (3D) microfluidic paper-based analytical device (3D-µPAD) for performing enzyme-linked immunosorbent assays (ELISA). To run an ELISA, the device requires only the addition of a small drop (2 µL per test zone) of sample and six drops (75 µL in total volume) of buffer solution. All the reagents required for the analysis are stored in dry form within the device, and are dissolved in the buffer and delivered to the test zones during the assay. The innovative feature of the device, which enables the delivery of different reagents and washes to the test zones without cross contamination, is a movable strip containing the test zones that can be moved manually through the device, and stops only at specified points where the test zones come into contact with different fluidic paths that sequentially transfer (i.e., wash) the reagents into the test zones. Using rabbit IgG as a model analyte, we performed an ELISA in 43 minutes, with a detection limit of 330 pM. We also demonstrated the detection of hepatitis B surface antigen (HBsAg) in serum.

Background: Respiratory diseases are an occupational health problem among farmers. In contrast, farming environment during childhood has been reported to protect from atopic sensitization and asthma. The prospective association between farming environment during infancy and lung function in adulthood has not been studied earlier. Aims: Investigate the prospective associations between farming environment during infancy and lung function at age 31. Methods: In a prospective birth cohort study, 5676 subjects born in northern Finland in 1966 were followed up at the age of 31 years. Prenatal exposure to the farming environment was documented prior to or at birth. At age 31, information on health status, current occupation and childhood pet exposure was collected by questionnaire. Forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) were measured by spirometry and ratio of FEV1: FVC calculated (FEV%). Multivariate linear regression models were used to adjust for multiple potential confounders. Results: To be born into a farmer family was associated with higher FEV1 (37 ml; 95% CI 5 to 68 ml) and FVC (40 ml; 95% CI 5 to 75 ml) at age 31. Having farm animals during infancy was associated with higher FEV1 (30 ml; 95% CI 1 to 60 ml). No associations were seen with FEV%. Having dogs in childhood showed similar associations. There was some suggestion for a dose-depended association with number of animal species during childhood and higher FEV1 and FVC at age 31, especially among women. Conclusion: Childhood in a farming environment may protect from restrictive-type lung function impairment during adulthood.

Introduction: Mediterranean-style dietary patterns (MSDPs) have been associated with lower risk of cardiometabolic diseases, but the underlying biological mechanisms are poorly understood. To date, little is known in humans of the relationship between MSDPs and epigenetics. We hypothesized that adherence to a MSDP is associated with DNA methylation, an important epigenetic modification. Methods: We conducted a cross-sectional study of 3,563 Framingham Heart Study participants (median age 59 years, 55% women). We excluded participants with heavy alcohol use. Whole-blood derived DNA methylation of 480,000 cytosine-phosphate-guanine dinucleotides (CpGs) was assessed using the Illumina HumanMethylation450 BeadChip. A MSDP score was created based on nine dietary components, including fruits, vegetables, legumes, nuts, whole grains, fish, red meat, alcohol, and ratio of monounsaturated fatty acids to saturated fatty acids. Food intake was assessed by a validated food frequency questionnaire. Our study sample was randomly split into separate discovery/replication groups (n=1,788 and n=1,775) by pedigrees. We tested the association of CpG methylation with the MSDP score using linear mixed model, adjusted for sex, age, and energy intake (as well as family structure, imputed leukocyte composition, and technical variables). CpGs identified in discovery at FDR<0.05 were taken forward for replication. We then tested the significance (Bonferroni corrected α 0.05) of the identified CpGs after additional adjustment for smoking, physical activity, and BMI in whole study sample. Results: One CpG, cg05575921 in the AHRR gene, was associated with MSDP score in the discovery sample ( P =3.3x10 -10 ) and replicated in the replication sample ( P =3.6x10 -5 ). In whole study sample, higher MSDP score was associated with greater methylation of cg05575921 after adjustment for sex, age, energy intake, smoking, physical activity, and BMI ( P =4.5x10 -3 ). Higher fruit and whole grain intake was also associated with higher methylation level of cg05575921 ( P =3.8x10 -7 and 5.1x10 -8 , respectively) and legume intake was associated with higher methylation level of cg17333223 (annotated to the NSA2 gene, P =1.3x10 -7 ). In contrast, fruit intake was associated with lower methylation of cg07035242 (annotated to the UBIAD1 gene, P =2.0x10 -7 ). These patterns persisted in the replication and in whole study sample. Conclusions: These data demonstrate a unique whole blood DNA methylation signature of a MSDP score and some of its individual components. The differentially methylated genes may represent therapeutic targets for prevention or treatment of cardiometabolic diseases. Future work is needed to explore the underlying mechanisms.

No abstract is provided for this article.

OBJECTIVE Genome-wide association studies have identified a single nucleotide polymorphism (SNP), rs560887, located in a G6PC2 intron that is highly correlated with variations in fasting plasma glucose (FPG). G6PC2 encodes an islet-specific glucose-6-phosphatase catalytic subunit. This study examines the contribution of two G6PC2 promoter SNPs, rs13431652 and rs573225, to the association signal. RESEARCH DESIGN AND METHODS We genotyped 9,532 normal FPG participants (FPG <6.1 mmol/l) for three G6PC2 SNPs, rs13431652 (distal promoter), rs573225 (proximal promoter), rs560887 (3rd intron). We used regression analyses adjusted for age, sex, and BMI to assess the association with FPG and haplotype analyses to assess comparative SNP contributions. Fusion gene and gel retardation analyses characterized the effect of rs13431652 and rs573225 on G6PC2 promoter activity and transcription factor binding. RESULTS Genetic analyses provide evidence for a strong contribution of the promoter SNPs to FPG variability at the G6PC2 locus (rs13431652: β = 0.075, P = 3.6 × 10−35; rs573225 β = 0.073 P = 3.6 × 10−34), in addition to rs560887 (β = 0.071, P = 1.2 × 10−31). The rs13431652-A and rs573225-A alleles promote increased NF-Y and Foxa2 binding, respectively. The rs13431652-A allele is associated with increased FPG and elevated promoter activity, consistent with the function of G6PC2 in pancreatic islets. In contrast, the rs573225-A allele is associated with elevated FPG but reduced promoter activity. CONCLUSIONS Genetic and in situ functional data support a potential role for rs13431652, but not rs573225, as a causative SNP linking G6PC2 to variations in FPG, though a causative role for rs573225 in vivo cannot be ruled out.

Introduction: Antibiotic exposure is associated with a long-lasting alteration in gut microbiota, and may be related to subsequent major chronic diseases such as cardiovascular diseases and cancer. No previous prospective cohort study has investigated associations between duration of antibiotic use during adulthood with mortality from major chronic diseases among populations at usual risk. Hypothesis: We investigated whether a longer duration of antibiotic use was associated with elevated risks of all-cause and cause-specific deaths among women. Methods: This study included 37,510 women aged ≥60 y who were initially free of cardiovascular diseases or cancer from the Nurses’ Health Study. The present analysis included women who reported data on antibiotic use on the 2004 questionnaire when the information was first assessed. We calculated hazard ratios (HR) for all-cause mortality, and deaths from cardiovascular disease (ICD-8 [international classification of diseases, eighth revision, ICD-8], codes 390 to 458) and cancer (ICD-8, 140-209) according to total days of antibiotic use per year (none, less than 15 days, 15 days to less than 2 months, or ≥2 months) in late adulthood (age 60 or older). Follow-up time was calculated from the return date of the 2004 questionnaire until the date of death, or end of follow-up (June 30, 2012), whichever occurred first. Results: During 287,474 person-years of follow-up, we documented 2908 deaths from any cause (including 474 cardiovascular deaths and 906 cancer deaths). Longer duration of antibiotic use was significantly associated with higher risk of death from any cause after adjusted for dietary intake, lifestyle factors, hypertension, hypercholesterolemia, diabetes ( P trend <0.0001), other medication use (such as aspirin, statin, H2 blockers, proton pump inhibitors) ( P trend =0.001), and other characteristics ( P trend =0.038). As compared to women who did not use antibiotics, those who used for ≥2 months in late adulthood had significantly increased risks of all-cause mortality (multivariate-adjusted HR 1.27; 95% CI, 1.07, 1.49) and cardiovascular mortality (HR 1.58; 95% CI, 1.02, 2.46), but not cancer mortality (HR=0.86; 95% CI, 0.63, 1.16). The association between long-term antibiotic use in late adulthood and an elevated risk of all-cause death was more evident among women who also used antibiotics in middle adulthood (during age 40-59) ( P trend =0.002) than among those who did not use during this life stage. Conclusions: Long-term duration of antibiotic exposure especially in late adulthood was associated with increased all-cause and cardiovascular mortality in women.