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BACKGROUND: Screening for islet autoantibodies in children and adolescents identifies individuals who will later develop type 1 diabetes, allowing patient and family education to prevent diabetic ketoacidosis at onset and to enable consideration of preventive therapies. We aimed to assess whether islet autoantibody screening is effective for predicting type 1 diabetes in adolescents aged 10−18 years with an increased risk of developing type 1 diabetes. METHODS: Data were harmonised from prospective studies from Finland (the Diabetes Prediction and Prevention study), Germany (the BABYDIAB study), and the USA (Diabetes Autoimmunity Study in the Young and the Diabetes Evaluation in Washington study). Autoantibodies against insulin, glutamic acid decarboxylase, and insulinoma-associated protein 2 were measured at each follow-up visit. Children who were lost to follow-up or diagnosed with type 1 diabetes before 10 years of age were excluded. Inverse probability censoring weighting was used to include data from remaining participants. Sensitivity and the positive predictive value of these autoantibodies, tested at one or two ages, to predict type 1 diabetes by the age of 18 years were the main outcomes. FINDINGS: Of 20 303 children with an increased type 1 diabetes risk, 8682 were included for the analysis with inverse probability censoring weighting. 1890 were followed up to 18 years of age or developed type 1 diabetes between the ages of 10 years and 18 years, and their median follow-up was 18·3 years (IQR 14·5–20·3). 442 (23·4%) of 1890 adolescents were positive for at least one islet autoantibody, and 262 (13·9%) developed type 1 diabetes. Time from seroconversion to diabetes diagnosis increased by 0·64 years (95% CI 0·34–0·95) for each 1-year increment of diagnosis age (Pearson’s correlation coefficient 0·88, 95% CI 0·50–0·97, p=0·0020). The median interval between the last prediagnostic sample and diagnosis was 0·3 years (IQR 0·1–1·3) in the 227 participants who were autoantibody positive and 6·8 years (1·6–9·9) for the 35 who were autoantibody negative. Single screening at the age of 10 years was 90% (95% CI 86–95) sensitive, with a positive predictive value of 66% (60–72) for clinical diabetes. Screening at two ages (10 years and 14 years) increased sensitivity to 93% (95% CI 89–97) but lowered the positive predictive value to 55% (49–60). INTERPRETATION: Screening of adolescents at risk for type 1 diabetes only once at 10 years of age for islet autoantibodies was highly effective to detect type 1 diabetes by the age of 18 years, which in turn could enable prevention of diabetic ketoacidosis and participation in secondary prevention trials. FUNDING: JDRF International.

OBJECTIVE To distinguish among predictors of seroconversion, progression to multiple autoantibodies and from multiple autoantibodies to type 1 diabetes in young children. RESEARCH DESIGN AND METHODS Genetically high-risk newborns (n = 8,502) were followed for a median of 11.2 years (interquartile range 9.3–12.6); 835 (9.8%) developed islet autoantibodies and 283 (3.3%) were diagnosed with type 1 diabetes. Predictors were examined using Cox proportional hazards models. RESULTS Predictors of seroconversion and progression differed, depending on the type of first appearing autoantibody. Male sex, Finnish residence, having a sibling with type 1 diabetes, the HLA DR4 allele, probiotic use before age 28 days, and single nucleotide polymorphism (SNP) rs689_A (INS) predicted seroconversion to IAA-first (having islet autoantibody to insulin as the first appearing autoantibody). Increased weight at 12 months and SNPs rs12708716_G (CLEC16A) and rs2292239_T (ERBB3) predicted GADA-first (autoantibody to GAD as the first appearing). For those having a father with type 1 diabetes, the SNPs rs2476601_A (PTPN22) and rs3184504_T (SH2B3) predicted both. Younger age at seroconversion predicted progression from single to multiple autoantibodies as well as progression to diabetes, except for those presenting with GADA-first. Family history of type 1 diabetes and the HLA DR4 allele predicted progression to multiple autoantibodies but not diabetes. Sex did not predict progression to multiple autoantibodies, but males progressed more slowly than females from multiple autoantibodies to diabetes. SKAP2 and MIR3681HG SNPs are newly reported to be significantly associated with progression from multiple autoantibodies to type 1 diabetes. CONCLUSIONS Predictors of IAA-first versus GADA-first autoimmunity differ from each other and from the predictors of progression to diabetes.

Objective: This study investigated physical activity and its association with the development of islet autoimmunity (IA) and type 1 diabetes in genetically at-risk 5-15 year old children. Research Design and Methods: As part of the longitudinal Environmental Determinants of Diabetes in the Young (TEDDY) study, annual assessment of activity using accelerometry was conducted from age 5. Time-to-event analyses using Cox proportional hazard models were used to assess the association between time spent in moderate-to-vigorous physical activity per day and the appearance of one or several autoantibodies and progression to type 1 diabetes in three risk groups: 1) 3869 IA negative children of whom 157 became single IA positive; 2) 302 single IA positive children of whom 73 became multiple IA positive; 3) 294 multiple IA positive children of whom 148 developed type 1 diabetes. Results: No significant association was found in risk group 1 or risk group 2. A significant association was seen in risk group 3 (HR = 0.920, 95% CI 0.856, 0.988 per 10 minutes, p = 0.021), particularly when GADA was the first autoantibody (HR = 0.883, 95% CI 0.783, 0.996 per 10 minutes, p=0.043). Conclusions: More daily minutes spent in moderate-to-vigorous physical activity was associated with a reduced risk of progression to type 1 diabetes in 5-15 year old children who had developed multiple islet autoantibodies.

Aims/hypothesis A key unanswered question in type 1 diabetes is whether beta cells initiate their own destruction or are victims of an aberrant immune response (beta cell suicide or homicide?). To investigate this, we assessed islet autoantibodies in individuals with congenital beta cell defects causing neonatal diabetes mellitus (NDM). Methods We measured autoantibodies to GAD (GADA), islet antigen-2 (IA-2A) and zinc transporter 8 (ZnT8A) in 242 individuals with NDM (median age diagnosed 1.8 months [IQR 0.39–2.9 months]; median age collected 4.6 months [IQR 1.8–27.6 months]; median diabetes duration 2 months [IQR 0.6–23 months]), including 75 whose NDM resulted from severe beta cell endoplasmic reticulum (ER) stress. As a control cohort we also tested samples from 69 diabetes-free individuals (median age collected 9.9 months [IQR 9.0–48.6 months]) for autoantibodies. Results We found low prevalence of islet autoantibodies in individuals with monogenic NDM; 13/242 (5.4% [95% CI 2.9, 9.0%]) had detectable GADA, IA-2A and/or ZnT8A. This was similar to the proportion in the control participants who did not have diabetes (1/69 positive [1.4%, 95% CI 0.03, 7.8%], p=0.3). Importantly, monogenic individuals with beta cell ER stress had a similar rate of GADA/IA-2A/ZnT8A positivity to non-ER stress aetiologies (2.7% [95% CI 0.3, 9.3%] vs 6.6% [95% CI 3.3, 11.5%] p=0.4). We observed no association between islet autoimmunity and genetic risk, age at testing (including 30 individuals >10 years at testing) or diabetes duration (p>0.4 for all). Conclusions/interpretation Our data support the hypothesis that beta cell stress/dysfunction alone does not lead to the production of islet autoantibodies, even in the context of high-risk HLA types. This suggests that additional factors are required to trigger an autoimmune response towards beta cells. Graphical abstract

Objective: To distinguish among predictors of seroconversion, progression to multiple autoantibodies and from multiple autoantibodies to type 1 diabetes in young children. Research Design and Methods: Genetically high-risk newborns (n=8502) were followed for a median of 11.2 y (IQR 9.3-12.6 y); 835 (9.8%) developed islet autoantibodies and 283 (3.3%) were diagnosed with type 1 diabetes. Predictors were examined using Cox proportional hazard models. Results: Predictors of seroconversion and progression differed, depending on the type of first appearing autoantibody. Male sex, Finnish residence, having a sibling with type 1 diabetes, the HLA DR4 allele, probiotic use before age 28 days, and SNP rs689_A (INS) predicted seroconversion to IAA-first. Increased weight at 12 months and SNPs rs12708716_G (CLEC16A) and rs2292239_T (ERBB3) predicted GADA-first. Having a father with type 1 diabetes, the SNPs rs2476601_A (PTPN22) and rs3184504_T (SH2B3) predicted both. Younger age at seroconversion predicted progression from single to multiple autoantibodies as well as progression to diabetes, except for those presenting with GADA-first. Family history of type 1 diabetes and the HLA DR4 allele predicted progression to multiple autoantibodies, but not diabetes. Sex did not predict progression to multiple autoantibodies, but males progressed more slowly than females from multiple autoantibodies to diabetes. SKAP2 and MIR3681HG SNPs are newly reported to be significantly associated with progression from multiple autoantibodies to type 1 diabetes. Conclusions: Predictors of IAA-first vs GADA-first autoimmunity differ from each other and from the predictors of progression to diabetes.

Objective: Biomarkers predicting risk of type 1 diabetes (Stage 3) among children with islet autoantibodies are greatly needed to prevent DKA and facilitate prevention therapies. Research Design and Methods: Children in the prospective TEDDY study (n=707) with confirmed diabetes-associated autoantibodies (GADA, IA-2A and/or IAA) and ≥2 HbA1c measurements were followed to diabetes or median age 11.1 years. Once confirmed autoantibody positive, HbA1c was measured quarterly. Cox models and receiver operative characteristic (ROC) analyses revealed the prognostic utility for risk of Stage 3 on a relative HbA1c increase from the baseline visit or an OGTT 2-hr plasma glucose (2-hPG). This HbA1c approach was then validated in the TrialNet Pathway to Prevention study (n=1190). Results: A 10% relative HbA1c increase from baseline best marked increased risk of Stage 3 in TEDDY (74% sensitive; 88% specific). Significant predictors of risk for HbA1c change were age and HbA1c at baseline test, genetic sex, maximum number of autoantibodies and maximum rate of HbA1c increase by time of change. The multivariable model featuring a HbA1c >10% increase and these additional factors revealed increased risk of Stage 3 in TEDDY (HR=12.74, 95%CI 8.7-18.6, p>10% increase performed similarly to an OGTT 2-hPG composite model (TEDDY AUC=0.88 and 0.85, respectively) and to the HbA1c model in TrialNet (AUC=0.82). Conclusion: An increase of >10% in HbA1c from baseline is as informative as OGTT 2-hPG in predicting risk of Stage 3 in youth with genetic risk and diabetes-associated autoantibodies.

During tumor growth-when nutrient and anabolic demands are high-autophagy supports tumor metabolism and growth through lysosomal organelle turnover and nutrient recycling. Ras-driven tumors additionally invoke non-autonomous autophagy in the microenvironment to support tumor growth, in part through transfer of amino acids. Here we uncover a third critical role of autophagy in mediating systemic organ wasting and nutrient mobilization for tumor growth using a well-characterized malignant tumor model in Drosophila melanogaster. Micro-computed X-ray tomography and metabolic profiling reveal that RasV12 ; scrib-/- tumors grow 10-fold in volume, while systemic organ wasting unfolds with progressive muscle atrophy, loss of body mass, -motility, -feeding, and eventually death. Tissue wasting is found to be mediated by autophagy and results in host mobilization of amino acids and sugars into circulation. Natural abundance Carbon 13 tracing demonstrates that tumor biomass is increasingly derived from host tissues as a nutrient source as wasting progresses. Thus, host autophagy mediates organ wasting and nutrient mobilization that is utilized for tumor growth. Citation Format: Petter Holland, Todd Andrew Schoborg, Ifat Abramovich, Szabolcs Takáts, Caroline Dillard, Ashish Jain, Fergal O'Farrell, Sebastian Wolfgang Schultz, William M. Hagopian, Eduardo Martin Quintana, Rachel Ng, Nadja Sandra Katheder, Mohammed Mahidur Rahman, José Gerardo Teles Reis, Andreas Brech, Heinrich Jasper, Nasser M. Rusan, Anne Hope Jahren, Eyal Gottlieb, Tor Erik Rusten. Host autophagy mediates organ wasting and nutrient mobilization for tumor growth [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr IA14.

OBJECTIVE Genetic risk scores (GRS) aid classification of diabetes type in White European adult populations. We aimed to assess the utility of GRS in the classification of diabetes type among racially/ethnically diverse youth in the U.S. RESEARCH DESIGN AND METHODS We generated type 1 diabetes (T1D)- and type 2 diabetes (T2D)-specific GRS in 2,045 individuals from the SEARCH for Diabetes in Youth study. We assessed the distribution of genetic risk stratified by diabetes autoantibody positive or negative (DAA+/−) and insulin sensitivity (IS) or insulin resistance (IR) and self-reported race/ethnicity (White, Black, Hispanic, and other). RESULTS T1D and T2D GRS were strong independent predictors of etiologic type. The T1D GRS was highest in the DAA+/IS group and lowest in the DAA−/IR group, with the inverse relationship observed with the T2D GRS. Discrimination was similar across all racial/ethnic groups but showed differences in score distribution. Clustering by combined genetic risk showed DAA+/IR and DAA−/IS individuals had a greater probability of T1D than T2D. In DAA− individuals, genetic probability of T1D identified individuals most likely to progress to absolute insulin deficiency. CONCLUSIONS Diabetes type–specific GRS are consistent predictors of diabetes type across racial/ethnic groups in a U.S. youth cohort, but future work needs to account for differences in GRS distribution by ancestry. T1D and T2D GRS may have particular utility for classification of DAA− children.

Objective: The Environmental Determinants of Diabetes in the Young (TEDDY) study is uniquely capable of investigating age-specific differences associated with type 1 diabetes. As age is a primary driver of heterogeneity in type 1 diabetes, we sought to characterize by age, metabolic derangements prior to diagnosis and clinical features associated with diabetic ketoacidosis (DKA). Research Design and Methods: The 379 TEDDY children who developed type 1 diabetes were grouped by age at onset (0-4, 5-9, and 10-14 years; n=142, 151 and 86, respectively) with comparisons of autoantibody profiles, HLA, family history of diabetes, presence of DKA, symptomatology at onset, and adherence to TEDDY protocol. Time-varying analysis of those with OGTT data was compared to TEDDY children who did not progress to diabetes. Results: Increasing fasting glucose (HR=1.09 (95% CI 1.04-1.14), p=0.0003), stimulated glucose (HR=1.50 (1.42-1.59), p Conclusions: DKA at onset in TEDDY is uncommon, especially for FDRs. For those without familial risk, metabolic monitoring continues to provide a primary benefit of reduced DKA but requires regular follow-up. Clinical and laboratory features vary by age at onset adding to the heterogeneity of type 1 diabetes.

Background: An estimated 10-30% of type 1 diabetes (T1D) individuals do not have detectable autoantibodies at diagnosis, thus are classified as “idiopathic” or “non-immune.” Given the non-pathogenic role of islet autoantibodies, the validity of excluding an immune basis for disease in such individuals needs to be questioned. The pan-autoantibody negative type 1 diabetes in adults (PANDA) study aims to characterise the immune, clinical and metabolic phenotype of autoantibody negative T1D individuals.Methods: This is a two-part, multi-centre study which is recruiting 100 participants: autoantibody positive T1D (N=25), autoantibody negative T1D (N=25), latent autoimmune diabetes in adults (N=25) and age- and sex-matched normoglycaemic control (N=25) individuals. Study 1 involves baseline pathology collection and high dimensional immune-phenotyping using flow cytometry. DNA will be extracted from saliva samples to calculate type 1 diabetes genetic risk scores (T1DGRS). Autoantibody negative individuals will undergo monogenic diabetes testing. Study 2 is a prospective, longitudinal sub-study of study 1 participants within 5 years of diagnosis. Beta cell function will be assessed using glucagon stimulated C-peptide at 0, 9 and 18 months. The primary outcome of study 1 is to determine the phenotype of immune cells in autoantibody positive and negative T1D compared to healthy controls. Secondary outcomes of study 1 include clinical and metabolic characteristics and the T1DGRS. The primary outcome of study 2 is the rate of decline of stimulated C-peptide over time. Conclusions: The PANDA study is the first study of its kind which aims to improve diagnosis and characterisation of autoantibody negative T1D.

During tumor growth—when nutrient and anabolic demands are high—autophagy supports tumor metabolism and growth through lysosomal organelle turnover and nutrient recycling. Ras‐driven tumors additionally invoke non‐autonomous autophagy in the microenvironment to support tumor growth, in part through transfer of amino acids. Here we uncover a third critical role of autophagy in mediating systemic organ wasting and nutrient mobilization for tumor growth using a well‐characterized malignant tumor model in Drosophila melanogaster. Micro‐computed X‐ray tomography and metabolic profiling reveal that RasV12; scrib −/− tumors grow 10‐fold in volume, while systemic organ wasting unfolds with progressive muscle atrophy, loss of body mass, ‐motility, ‐feeding, and eventually death. Tissue wasting is found to be mediated by autophagy and results in host mobilization of amino acids and sugars into circulation. Natural abundance Carbon 13 tracing demonstrates that tumor biomass is increasingly derived from host tissues as a nutrient source as wasting progresses. We conclude that host autophagy mediates organ wasting and nutrient mobilization that is utilized for tumor growth., X‐ray tomography, metabolomics and carbon tracing reveal that autophagy‐mediated wasting of distal tissues provides amino acids and sugars that increase eye tumor biomass in Drosophila melanogaster.

Understanding how agricultural societies were impacted and adapted to past climate variations is critical to face to contemporary climate change and guaranty the food security (#SDG2 Zero Hunger). However, linking climate and change in the behaviour of a population are difficult to evidence. Here, we studied the climate variations of the period between 200 and 1300 CE and its impact on the pre-Viking and Viking societies in Southeastern Norway, including the adaptation and resilience of the agricultural management. This period includes, between 300 and 800 CE, one of the coldest period of the last 2000 years. We used a retrospective approach combining a multi-proxy analysis of lake sediments, including geochemical and palynological analyses, to reconstruct past changes in temperature and agricultural practices during the period 200-1300 CE. We associated variations in Ca/Ti ratio as a result of change in lake productivity with the temperature. The periods 200-300 and 800-1300 CE were warmer than the period between 300 and 800 CE, which is known as the “Dark Ages Cold Period” in the Northern Hemisphere. During this colder period, phases dominated by grazing activities (280-420 CE, 480-580 CE, 700-780 CE) alternated with phases dominated by the cultivation of cereals and hemp (before 280 CE, 420-480 CE, 580-700 CE, and after 800 CE). The alternation of these phases is synchronous of temperature changes. Cold periods are associated to livestock farming, and warmer periods to crop farming. This result suggests that when temperature no longer allowed crop farming, the food production specialized in animal breeding. The result of a Principal Component Analysis show a succession of phases of crisis, adaptation and resilience of the socio-environmental system. The Viking Age (800-1000 CE) started with an increase in temperature and corresponds to the warmest period between 200 and 1300 CE, allowing a larger development of the agriculture practices and society. Our results prove that the pre-Viking society adapted their agricultural practices to the climate variability of the Late Antiquity and that the Vikings expanded with climate warming.

The Permian period ended with a mass extinction event about 252 million years ago. A likely trigger of the mass extinction was the eruption of large volumes of magma which had moved through the Tunguska Basin in Siberia. The renowned Festningen section in the outer part of Isfjorden, western Spitsbergen, offers a c. 7 km long nearly continuous stratigraphic section of Lower Carboniferous to Cenozoic strata, where the end-Permian extinction interval is well-exposed. Tectonic deformation associated with the Paleogene West Spitsbergen fold-and-thrust-belt tilted the strata to near-vertical, allowing easy access along the shoreline. The section is a regionally important stratigraphic reference profile and is a key locality for geologists visiting Svalbard. The main objective of our fieldwork in September 2020 was to collect closely spaced mudstone (0.25 to 1 m interval) and ash layer (6 layers of 0.5 to 1.5 cm thickness) samples across the Festningen Permian-Triassic boundary for chemostratigraphic and geochronological assessments. Carbon isotope data reveal a well-defined negative deltaC13 excursion in the lower part of the Vardebukta Fm. Zircons are present in most of the ash layer samples and these will be dated at the University of Oslo TIMS U-Pb Isotope Geology Laboratory. In this contribution, we will also present a new digital outcrop model of the P-Tr boundary section acquired using a UAV (Mavic 2 Pro, 20MP Hasselblad camera). During acquisition, the maximum drone speed was set to 1 meter/second (i.e., “tripod mode”), and photographs were taken automatically at set time intervals (e.g., 1 photo every 5 seconds ≈ meters). The digital outcrop model offers a pixel resolution of 7.27 mm/pixel. The Festningen model will be available online through the Svalbox.no geoscience data platform.

OBJECTIVE Islet autoimmunity develops before clinical type 1 diabetes and includes multiple and single autoantibody phenotypes. The objective was to determine age-related risks of islet autoantibodies that reflect etiology and improve screening for presymptomatic type 1 diabetes. RESEARCH DESIGN AND METHODS The Environmental Determinants of Diabetes in the Young study prospectively monitored 8,556 genetically at-risk children at 3- to 6-month intervals from birth for the development of islet autoantibodies and type 1 diabetes. The age-related change in the risk of developing islet autoantibodies was determined using landmark and regression models. RESULTS The 5-year risk of developing multiple islet autoantibodies was 4.3% (95% CI 3.8–4.7) at 7.5 months of age and declined to 1.1% (95% CI 0.8–1.3) at a landmark age of 6.25 years (P < 0.0001). Risk decline was slight or absent in single insulin and GAD autoantibody phenotypes. The influence of sex, HLA, and other susceptibility genes on risk subsided with increasing age and was abrogated by age 6 years. Highest sensitivity and positive predictive value of multiple islet autoantibody phenotypes for type 1 diabetes was achieved by autoantibody screening at 2 years and again at 5–7 years of age. CONCLUSIONS The risk of developing islet autoimmunity declines exponentially with age, and the influence of major genetic factors on this risk is limited to the first few years of life.

During tumor growth - when nutrient and anabolic demands are high – autophagy supports tumor metabolism and growth through lysosomal organelle turnover and nutrient recycling1. Ras-driven tumors additionally invoke non-autonomous autophagy in the microenvironment to support tumor growth, in part through transfer of amino acids2–4. Here we uncover a third critical role of autophagy in mediating systemic organ wasting and nutrient mobilization for tumor growth using a well-characterized malignant tumor model in Drosophila melanogaster. Micro-computed X-ray tomography and metabolic profiling reveal that RasV12; scrib-/- tumors grow 10-fold in volume, while systemic organ wasting unfolds with progressive muscle atrophy, loss of body mass, −motility, −feeding and eventually death. Tissue wasting is found to be mediated by autophagy and results in host mobilization of amino acids and sugars into circulation. Natural abundance Carbon 13 tracing demonstrates that tumor biomass is increasingly derived from host tissues as a nutrient source as wasting progresses. We conclude that host autophagy mediates organ wasting and nutrient mobilization that is utilized for tumor growth.

Rationale Subambient pCO2 has persisted across the major Phanerozoic ice ages, including the entire late Cenozoic (ca 30 Ma to present). Stable isotope analysis of plant-derived organic matter is used to infer changes in pCO2 and climate in the geologic past, but a growth chamber that can precisely control environmental conditions, including pCO2 and δ13 C value of CO2 (δ13 CCO2 ) at subambient pCO2 , is lacking. Methods We designed and built five identical chambers specifically for plant growth under stable subambient pCO2 (ca 100 to 400 ppm) and δ13 CCO2 conditions. We tested the pCO2 and δ13 CCO2 stability of the chambers both with and without plants, across two 12-hour daytime experiments and two extended 9-day experiments. We also compared the temperature and relative humidity conditions among the chambers. Results The average δ13 CCO2 value within the five chambers ranged from -18.76 to -19.10‰; the standard deviation never exceeded 0.14‰ across any experiment. This represents better δ13 CCO2 stability than that achieved by all previous chamber designs, including superambient pCO2 chambers. Every pCO2 measurement (n = 1225) was within 5% of mean chamber values. The temperature and relative humidity conditions differed by no more than 0.4°C and 1.6%, respectively, across all chambers within each growth experiment. Conclusions This growth chamber design extends the range of pCO2 conditions for which plants can be grown for δ13 C analysis of their tissues at subambient levels. This new capability allows for careful isolation of environmental effects on plant 13 C discrimination across the entire range of pCO2 experienced by terrestrial land plants.

Subambient pCOWe designed and built five identical chambers specifically for plant growth under stable subambient pCOThe average δThis growth chamber design extends the range of pCO

RATIONALE Stable isotope analysis (SIA), a potential method of verifying the geographic origin and production method of dairy products, has not been applied to United States (U.S.) dairy samples on a national scale. To determine the potential of carbon and nitrogen SIA in authenticity assessment of U.S. dairy products, we analyzed a geographically representative collection of conventional milk samples to determine isotopic variations with (1) Purchase Location and (2) Macronutrient Content. METHODS A total of 136 milk samples spanning five commercially available varieties (3.25% [i.e., 'whole'], 2%, 1%, 0% [i.e., 'skim'] and 1% chocolate) were collected from randomly selected counties across the U.S. as part of the United States Department of Agriculture's (USDA's) National Food and Nutrient Analysis program. δ13 C and δ15 N values of bulk samples determined via elemental analysis/isotope ratio mass spectrometry (EA/IRMS) were used to assess the contribution of fat content, added sugar content and census-designated region of collection to isotopic variations within the dataset. RESULTS There was a negative linear relationship between fat content and δ13 C values, with average milk δ13 C values decreasing by 0.33‰ for each 8.75% increase in dry weight (1% wet weight) fat content. The average δ13 C value of flavored 1% chocolate milk samples, which contain an additional 12 g of added sugar, was 2.05‰ higher than that of 1% unflavored milk (-16.47‰ for chocolate milk vs -18.52‰ for unflavored milk). When controlling for macronutrient content, milk samples collected in West region supermarkets possessed significantly lower δ13 C values than samples collected from Midwest, South, and Northeast regions. δ15 N values did not vary with macronutrient content or region of collection. CONCLUSIONS Carbon stable isotope ratios in U.S. milk samples varied with macronutrient content and region of purchase, suggesting that SIA can provide insight into production processes within the U.S. dairy industry, with potential applications in national food adulteration and authentication efforts.

RATIONALE Accurate online analysis of the δ18O values of nitrogen-bearing organic compounds is of interest to several emergent fields, including ecology, forensics and paleontology. During online analysis, high-temperature conversion (HTC) of nitrogen-bearing organics produces N2 gas which creates isobaric interference with the isotopic measurement. Specifically, N2 reacts with trace amounts of oxygen in the mass spectrometer source to form 14N16O (m/z 30), which prevents accurate evaluation of the sample 12C18O peak (m/z 30). METHODS We present an alternative system to the conventional HTC, which uses a nickel-catalyzed (“NiCat”) reduction furnace to convert HTC-produced CO into CO2, allowing for δ18O measurement using signal intensities at m/z 44 and 46. RESULTS This system yields identical δ18O values for nitrogen-doped and undoped sucrose and cellulose compounds up to molar yield ratios of N2:CO = 0.22. In contrast, our conventional HTC system configured to factory recommendations with the stock gas chromatography (GC) column produced a discrepancy of ~5‰ between nitrogen-doped and undoped samples. CONCLUSIONS Because of its ability to eliminate isobaric interference, the NiCat system is a viable alternative to conventional HTC for δ18O measurement, and can be constructed from relatively inexpensive and readily available materials. As an additional advantage, the CO2 analyte produced by NiCat may be cryofocused, to allow for oxygen-isotope determinations on very small amounts of sample substrate. Copyright © 2012 John Wiley & Sons, Ltd.

The measurement of the oxygen stable isotope content in organic compounds has applications in many fields, ranging from paleoclimate reconstruction to forensics. Conventional High-Temperature Conversion (HTC) techniques require >20 µg of O for a single δ18O measurement. Here we describe a system that converts the CO produced by HTC into CO2 via reduction within a Ni-furnace. This CO2 is then concentrated cryogenically, and 'focused' into the isotope ratio mass spectrometry (IRMS) source using a low-flow He carrier gas (6–8 mL/min). We report analyses of benzoic acid (C7H6O2) reference materials that yielded precise δ18O measurement down to 1.3 µg of O, suggesting that our system could be used to decrease sample requirement for δ18O by more than an order of magnitude. Copyright © 2010 John Wiley & Sons, Ltd.

BACKGROUND & AIMS: It is not clear how intake of gluten during infancy affects subsequent risk of celiac disease. We investigated whether gluten intake before 2 years of age increases risk for celiac disease in genetically susceptible children. METHODS: We performed a case-control study of 436 pairs of children, generated from a database of 2525 children with genetic susceptibility to celiac disease in Sweden, matched for sex, birth year, and HLA genotype from September 2004 and February 2010. Children were screened annually for celiac disease using an assay for tissue transglutaminase autoantibodies (tTGA). Intestinal biopsies were collected from children who tested positive for tTGA to confirm the presence of celiac disease. Gluten intake was calculated from 3-day food records collected when the children were 9, 12, 18 and 24 months old. RESULTS: Breastfeeding duration (median 32 weeks) and age at first introduction to gluten (median 22 weeks) did not differ between cases and tTGA-negative children (controls). At the visit prior to tTGA seroconversion, cases reported a larger intake of gluten (median 4.9 g/day) than controls (median 3.9 g/day) (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.13-1.46; P=.0002). More cases consumed amounts of gluten in the upper 3rd tertile (i.e. >5.0 g/day) before they tested positive for tTGA seroconversion than controls (OR, 2.65; 95% CI, 1.70-4.13; P

Throughout at least the next century, CO(2) fertilization and environmental stresses (e.g. nutrient, moisture, insect herbivory) are predicted to affect yields of economically important crop species. Stable isotopes of carbon are used to study plant stresses, which affect yields, but a growth chamber design that can be used to isolate the effects of environmental stresses on crop-sized species through precise maintenance of pCO(2) levels and the δ(13)C values of atmospheric CO(2) (δ(13) C(CO2)) is lacking.We designed and built low-cost plant growth chambers for growing staple crop species under precise pCO(2) and δ(13) C(CO2) conditions. Over the course of 14 hours, we assessed for pCO(2) stability at two targeted levels (ambient, ~400 ppm; and 2×, ~800 ppm) and measured the δ(13) C(CO2) value within the two chambers using a stable isotope ratio mass spectrometer. We also compared the temperature and relative humidity conditions within the two growth chambers, and in the ambient, outside air.Across our experimental period, we achieved δ(13) C(CO2) stability (ambient: -8.05 ± 0.17‰; elevated: -12.99 ± 0.29‰) that showed nearly half the variability of any previously reported values for other chamber designs. The stability of the pCO(2) conditions (ambient: 406 ± 3 ppm; elevated: 793 ± 54 ppm) was comparable with that in previous studies, but our design provided ~8 times more growing space than previous chamber designs. We also measured nearly identical temperature and relative humidity conditions for the two chambers throughout the experiment.Our growth chamber design marks a significant improvement in our ability to test for plant stress across a range of future pCO(2) scenarios. Through significant improvement in δ(13) C(CO2) stability and increased chamber size, small changes in carbon isotope fractionation can be used to assess stress in crop species under specific environmental (temperature, relative humidity, pCO(2)) conditions.

Accurate online analysis of the δ(18)O values of nitrogen-bearing organic compounds is of interest to several emergent fields, including ecology, forensics and paleontology. During online analysis, high-temperature conversion (HTC) of nitrogen-bearing organics produces N(2) gas which creates isobaric interference with the isotopic measurement. Specifically, N(2) reacts with trace amounts of oxygen in the mass spectrometer source to form (14)N(16)O (m/z 30), which prevents accurate evaluation of the sample (12)C(18)O peak (m/z 30).We present an alternative system to the conventional HTC, which uses a nickel-catalyzed ("NiCat") reduction furnace to convert HTC-produced CO into CO(2), allowing for δ(18)O measurement using signal intensities at m/z 44 and 46.This system yields identical δ(18)O values for nitrogen-doped and undoped sucrose and cellulose compounds up to molar yield ratios of N(2):CO = 0.22. In contrast, our conventional HTC system configured to factory recommendations with the stock gas chromatography (GC) column produced a discrepancy of ~5‰ between nitrogen-doped and undoped samples.Because of its ability to eliminate isobaric interference, the NiCat system is a viable alternative to conventional HTC for δ(18)O measurement, and can be constructed from relatively inexpensive and readily available materials. As an additional advantage, the CO(2) analyte produced by NiCat may be cryofocused, to allow for oxygen-isotope determinations on very small amounts of sample substrate.

Although the advantages of online δ(18)O analysis of organic compounds make its broad application desirable, researchers have encountered NO(+) isobaric interference with CO(+) at m/z 30 (e.g. (14)N(16)O(+), (12)C(18)O(+)) when analyzing nitrogenous substrates. If the δ(18)O value of inter-laboratory standards for substrates with high N:O value could be confirmed offline, these materials could be analyzed periodically and used to evaluate δ(18)O data produced online for nitrogenous unknowns. To this end, we present an offline method based on modifications of the methods of Schimmelmann and Deniro (Anal. Chem. 1985; 57: 2644) and Sauer and Sternberg (Anal. Chem. 1994; 66: 2409), whereby all the N(2) from the gas products of a chlorinated pyrolysis was eliminated, resulting in purified CO(2) for analysis via a dual-inlet isotope ratio mass spectrometry system. We evaluated our method by comparing observed δ(18)O values with previously published or inter-laboratory calibrated δ(18)O values for five nitrogen-free working reference materials; finding isotopic agreement to within ±0.2‰ for SIGMA® cellulose, IAEA-CH3 cellulose (C(6)H(10)O(5)) and IAEA-CH6 sucrose (C(12)H(22)O(11)), and within ±1.8‰ for IAEA-601 and IAEA-602 benzoic acids (C(7)H(6)O(2)). We also compared the δ(18)O values of IAEA-CH3 cellulose and IAEA-CH6 sucrose that was nitrogen-'doped' with adenine (C(5)H(5)N(5)), imidazole (C(3)H(4)N(2)) and 2-aminopyrimidine (C(4)H(5)N(3)) with the undoped δ(18)O values for the same substrates; yielding isotopic agreement to within ±0.7‰. Finally, we provide an independent analysis of the δ(18)O value of IAEA-600 caffeine (C(8)H(10)N(4)O(2)), previously characterized using online systems exclusively, and discuss the reasons for an average 1.4‰ enrichment in δ(18)O observed offline relative to the consensus online δ(18)O value.

The measurement of the oxygen stable isotope content in organic compounds has applications in many fields, ranging from paleoclimate reconstruction to forensics. Conventional High-Temperature Conversion (HTC) techniques require20 microg of O for a single delta(18)O measurement. Here we describe a system that converts the CO produced by HTC into CO(2) via reduction within a Ni-furnace. This CO(2) is then concentrated cryogenically, and 'focused' into the isotope ratio mass spectrometry (IRMS) source using a low-flow He carrier gas (6-8 mL/min). We report analyses of benzoic acid (C(7)H(6)O(2)) reference materials that yielded precise delta(18)O measurement down to 1.3 microg of O, suggesting that our system could be used to decrease sample requirement for delta(18)O by more than an order of magnitude.

We have developed a reverse-phase HPLC method to purify 125I-labeled products resulting from the chloramine-T-based iodination of glucagon and have used the products [(125I)iodoTyr13]glucagon, [(125I)iodoTyr10,13]glucagon, and [(125I)iodoTyr10]glucagon) to study the receptor binding of glucagon and the cell-mediated metabolism of the hormone by isolated canine hepatocytes. The extent of binding of the three labeled glucagons to cell receptors differed at steady state (8.5, 11.9, and 12.6% of the three peptides, respectively, becoming cell-associated), but each of the labeled glucagons approached steady state binding at the same rate. Further, unlabeled glucagon competed for the binding of each of the labeled peptides in parallel under steady state conditions, and each of the peptides showed potent activity in inhibiting [14C]fructose incorporation into glycogen. Gel filtration of the acetic acid-extracted, cell-associated products of radiolabeled glucagon binding revealed 10-20% of the material as a shoulder on the descending limb of the peak of hormone for each of the three labeled peptides. Trypsin digestion of the lower molecular weight peptide derived from [(125I)iodoTyr13]glucagon resulted in a fragment containing residues 13 to 17 as the only detectable radiolabeled product. On the other hand, trypsin digestion of the analogous peptide derived from [(125I)iodoTyr10]glucagon revealed, in addition to the radiolabeled fragment containing residues 1 to 12, a major fragment identified by radiosequence analysis to contain residues 4 to 12 and a minor fragment identified to contain residues 7 to 12. We conclude that (a) notwithstanding apparent differences in affinities exhibited by [(125I)iodoTyr13]glucagon, [(125I)iodoTyr10,13]glucagon, and [(125I)iodoTyr10]glucagon for binding to canine hepatocytes, the interactions of all three peptides with the glucagon receptor are functionally equivalent, and (b) the cell-mediated metabolism of receptor-bound glucagon involves the formation of hormone-derived peptides in which the biologically important NH2-terminal region of the hormone has been modified by limited proteolytic cleavage.

A patient who developed Pneumocystis carinii hepatitis and choroiditis despite receiving prophylactic pentamidine therapy by aerosol is described. Liver biopsy showed histology typical of Pneumocystis hepatitis, but his respiratory status was stable and his lungs were free of P carinii organisms on BAL. Thus, inhaled pentamidine prophylaxis did not prevent extrapulmonary pneumocystosis. Patients receiving pentamidine prophylaxis with unexplained symptoms should undergo investigation for possible extrapulmonary P carinii infection.