| 1. |
- Alseekh, Saleh, et al.
(författare)
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Mass spectrometry-based metabolomics: a guide for annotation, quantification and best reporting practices
- 2021
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Ingår i: Nature Methods. - : Springer Science and Business Media LLC. - 1548-7091 .- 1548-7105. ; 18:7, s. 747-756
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Forskningsöversikt (refereegranskat)abstract
- This Perspective, from a large group of metabolomics experts, provides best practices and simplified reporting guidelines for practitioners of liquid chromatography- and gas chromatography-mass spectrometry-based metabolomics. Mass spectrometry-based metabolomics approaches can enable detection and quantification of many thousands of metabolite features simultaneously. However, compound identification and reliable quantification are greatly complicated owing to the chemical complexity and dynamic range of the metabolome. Simultaneous quantification of many metabolites within complex mixtures can additionally be complicated by ion suppression, fragmentation and the presence of isomers. Here we present guidelines covering sample preparation, replication and randomization, quantification, recovery and recombination, ion suppression and peak misidentification, as a means to enable high-quality reporting of liquid chromatography- and gas chromatography-mass spectrometry-based metabolomics-derived data.
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| 2. |
- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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| 3. |
- Agrasada, Grace V., et al.
(författare)
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Exclusive breastfeeding of low birth weight infants for the first six months : infant morbidity and maternal and infant anthropometry
- 2011
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Ingår i: Asia Pacific Journal of Clinical Nutrition. - : H E C Press. - 0964-7058 .- 1440-6047. ; 20:1, s. 62-68
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Tidskriftsartikel (refereegranskat)abstract
- Background: to report anthropometry and morbidity among term low birth weight infants and anthropometry of their first time mothers during the first six months in relation to breastfeeding practice. Methods: we examined data from a randomized controlled trial in Manila, the Philippines. Of the 204 mothers randomized, 68 mothers received eight postpartum breastfeeding counseling sessions, the rest did not. Maternal and infant anthropometric data at birth, 2, 4 and 6 months were taken. During seven follow-up hospital visits, an independent interviewer recorded feeding data. Results: the 24 infants exclusively breastfed from birth to six months did not have diarrhea compared to 134 partially breastfed (mean 2.3 days) and 21 non-breastfed infants (mean 2.5 days). Partially breastfed and non-breastfed infants compared to exclusively breastfed infants had more frequent, as well as more severe episodes of respiratory infections. At six months, neither overall gain in infant weight, length and head circumferences nor mean maternal weight and body mass index differed significantly between the feeding groups. Conclusions: exclusive breastfeeding for 6 months can be recommended in term low birth weight infants, who were protected from diarrhea, had fewer respiratory infections, required no hospitalization and had catch up growth. Exclusively breastfeeding mothers did not differ from mothers who breastfed partially or those who did not breastfeed with regard to weight changes at six months.
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| 4. |
- Agrasada, Grace V., 1956-
(författare)
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Postnatal Peer Counseling on Exclusive Breastfeeding of Low-birthweight Filipino Infants : Results of a Randomized Controlled Trial
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a Manila hospital, 204 mothers were randomized into three groups: two intervention groups receiving home-based counseling visits, one of them (n=68) by counselors trained to use a locally developed, two-tiered program of breastfeeding counseling, and the other by counselors trained in general childcare (n=67), were compared with a control group of mothers (n=69) who did not receive any counseling. All infants were scheduled for seven visits to the hospital for follow-up. During hospital visits, maternal and infant body measurements were made and an independent interviewer asked the mothers individually to recall how the infant had been fed. One study physician, blind to participant groups, was consulted at all scheduled and unscheduled infant visits.At six months, 44% of the breastfeeding-counseled mothers, 7% of the childcare-counseled mothers and none of the mothers in the control group were exclusively breastfeeding. Twenty- four mothers breastfed exclusively during the first six months, of whom 22 received breastfeeding counseling and 2 had no breastfeeding counseling. Among 24 infants who were exclusively breastfed from birth to six months there were no episodes of diarrhea. All infants had gained in weight, length and head circumference. Mean maternal weight loss at six months was similar whether her breastfeeding was exclusive or partial.The reasons why mothers without breastfeeding counseling introduced non-breast milk feeding before six months reflected lack of knowledge and support. Breastfeeding support during the first six months focusing on how to prevent and solve breastfeeding problems, particularly during the first two weeks, will enable mothers to choose to breastfeed exclusively up to six months. This study has provided fundamental evidence of successful intervention by breastfeeding counseling to achieve six months of exclusive breastfeeding among term, low-birthweight infants. The locally developed training program in breastfeeding counseling, which successfully prepared volunteers to counsel mothers at home, could be incorporated into primary health care in the Philippines. Mothers who received breastfeeding counseling appreciated how this helped them to achieve their breastfeeding goals for the first six months. Improved breastfeeding practices as a result of breastfeeding counseling provided infants with protection from diarrhea and respiratory infections, contributing to their health and development.
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| 5. |
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| 6. |
- Ahlsson, Fredrik, 1967-, et al.
(författare)
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Adipokines and their relation to maternal energy substrate production, insulin resistance and fetal size
- 2013
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Ingår i: European Journal of Obstetrics, Gynecology, and Reproductive Biology. - : Elsevier BV. - 0301-2115 .- 1872-7654. ; 168:1, s. 26-29
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:The role of adipokines in the regulation of energy substrate production in non-diabetic pregnant women has not been elucidated. We hypothesize that serum concentrations of adiponectin are related to fetal growth via maternal fat mass, insulin resistance and glucose production, and further, that serum levels of leptin are associated with lipolysis and that this also influences fetal growth. Hence, we investigated the relationship between adipokines, energy substrate production, insulin resistance, body composition and fetal weight in non-diabetic pregnant women in late gestation.STUDY DESIGN:Twenty pregnant women with normal glucose tolerance were investigated at 36 weeks of gestation at Uppsala University Hospital. Levels of adipokines were related to rates of glucose production and lipolysis, maternal body composition, insulin resistance, resting energy expenditure and estimated fetal weights. Rates of glucose production and lipolysis were estimated by stable isotope dilution technique.RESULTS:Median (range) rate of glucose production was 805 (653-1337)μmol/min and that of glycerol production, reflecting lipolysis, was 214 (110-576)μmol/min. HOMA insulin resistance averaged 1.5±0.75 and estimated fetal weights ranged between 2670 and 4175g (-0.2 to 2.7 SDS). Mean concentration of adiponectin was 7.2±2.5mg/L and median level of leptin was 47.1 (9.9-58.0)μg/L. Adiponectin concentrations (7.2±2.5mg/L) correlated inversely with maternal fat mass, insulin resistance, glucose production and fetal weight, r=-0.50, p<0.035, r=-0.77, p<0.001, r=-0.67, p<0.002, and r=-0.51, p<0.032, respectively. Leptin concentrations correlated with maternal fat mass and insulin resistance, r=0.76, p<0.001 and r=0.73, p<0.001, respectively. There was no correlation between maternal levels of leptin and rate of glucose production or fetal weight. Neither were any correlations found between levels of leptin or adiponectin and maternal lipolysis or resting energy expenditure.CONCLUSION:The inverse correlations between levels of maternal adiponectin and insulin resistance as well as endogenous glucose production rates indicate that low levels of adiponectin in obese pregnant women may represent one mechanism behind increased fetal size. Maternal levels of leptin are linked to maternal fat mass and its metabolic consequences, but the data indicate that leptin lacks a regulatory role with regard to maternal lipolysis in late pregnancy.
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| 7. |
- Ahlsson, Fredrik, 1967-
(författare)
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Being Born Large for Gestational Age : Metabolic and Epidemiological Studies
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is a major health problem in the Western world. Mean birth weight has increased during the last 25 years. One explanation is that the proportion of large for gestational age (LGA) infants has increased. Such infants risk developing obesity, cardiovascular disease and diabetes later in life. Despite the risk of neonatal hypoglycemia, their postnatal metabolic adaptation has not been investigated. Our data, obtained with stable isotope labeled compounds, demonstrate that newborn LGA infants have increased lipolysis and decreased insulin sensitivity. After administration of glucagon, the plasma levels of glucose and the rate of glucose production increased. The simultaneous increase in insulin correlated with the decrease in lipolysis, indicating an antilipolytic effect of insulin in these infants.We also demonstrated an intergenerational effect of being born LGA, since women born LGA, were at higher risk of giving birth to LGA infants than women not born LGA. Further, the LGA infants formed three subgroups: born long only, born heavy only, and born both long and heavy. Infants born LGA of women with high birth weight or adult obesity were at higher risk of being LGA concerning weight alone, predisposing to overweight and obesity at childbearing age. In addition we found that pregnant women with gestational diabetes were at increased risk of giving birth to infants that were heavy alone. This could explain the risk of both perinatal complications and later metabolic disease in infants of this group of women.To identify determinants of fetal growth, 20 pregnant women with a wide range of fetal weights were investigated at 36 weeks of gestation. Maternal fat mass was strongly associated with insulin resistance. Insulin resistance was related to glucose production, which correlated positively with fetal size. The variation in resting energy expenditure, which was closely related to fetal weight, was largely explained by BMI, insulin resistance, and glucose production. Lipolysis was not rate limiting for fetal growth in this group of women. Consequently, high maternal glucose production due to a high fat mass may result in excessive fetal growth.
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| 8. |
- Ahlsson, Fredrik, et al.
(författare)
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Insulin Resistance, a Link between Maternal Overweight and Fetal Macrosomia in Nondiabetic Pregnancies
- 2010
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Ingår i: Hormone research in paediatrics. - : S. Karger AG. - 1663-2818 .- 1663-2826. ; 74:4, s. 267-274
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: During the last decades the number of large for gestational age infants delivered by nondiabetic mothers has increased. Our aim was to investigate to what extent fetal growth in nondiabetic pregnant women can be explained by rates of maternal energy substrate production and resting energy expenditure. Methods: Twenty nonsmoking pregnant women without impaired glucose tolerance and with a wide range of fetal weights (0.2-2.7 SDS) were investigated at 36 weeks of gestation. Maternal lipolysis, glucose production, resting energy expenditure, body composition and insulin resistance were assessed.Results: Median (range) glucose production rate was 805 (653-1,337) mumol/min and that of glycerol, reflecting lipolysis, was 214 (110-576) mumol/min. Multiple linear regression analysis showed that maternal fat mass explained 36% of the variation in insulin resistance, accounting for 62% of the variation in glucose production. Further, glucose production explained 31% of the variation in fetal weight. Resting energy expenditure explained 51% of the variation in estimated fetal weight. Conclusion: Fetal weight is dependent on maternal glucose production, which is in turn determined by the degree of insulin resistance, induced in part by the maternal fat mass. The variation in maternal resting energy expenditure is closely related to fetal weight.
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| 9. |
- Ahlsson, Fredrik, et al.
(författare)
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Lipolysis and Insulin Sensitivity at Birth in Infants Who Are Large for Gestational Age
- 2007
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Ingår i: Pediatrics. - : American Academy of Pediatrics (AAP). - 0031-4005 .- 1098-4275. ; 120:5, s. 958-965
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE. In addition to neonatal hypoglycemia, infants who are born large for gestational age are at risk for developing obesity, cardiovascular disease, and diabetes later in life. The aim of this study was to investigate glucose production, lipolysis, and insulin sensitivity in infants who were born large for gestational age to mothers without diabetes. The effect of glucagon administration on production of energy substrates was also investigated. METHODS. Ten healthy term infants who were born large for gestational age to mothers without diabetes were studied 16 ± 8 hours postnatally after a 3-hour fast. Rates of glucose production and lipolysis were analyzed by gas chromatography–mass spectrometry following constant rate infusion of [6,6-2H2]glucose and [2-13C]glycerol. Insulin sensitivity was assessed by the Homeostasis Assessment Model. In 8 of the infants, the effect of an intravenous injection of 0.2 mg/kg glucagon was also analyzed. RESULTS. Plasma glucose and glycerol averaged 3.8 ± 0.5 mmol/L and 384 ± 183 µmol/L, respectively. The glycerol production rate, reflecting lipolysis, was 12.7 ± 2.9 µmol/kg per min. Mean rate of glucose production was 30.2 ± 4.6 µmol/kg per min. Homeostasis Assessment Model insulin sensitivity corresponded to 82% ± 19%, β-cell function to 221% ± 73%, and insulin resistance to 1.3 ± 0.3. After glucagon administration, rate of glucose production increased by 13.3 ± 8.3 µmol/kg per min and blood glucose by 1.4 ± 0.5 mmol/L. Glycerol production decreased from 12.8 ± 3.0 to 10.7 ± 2.9 µmol/kg per min. Mean insulin concentration increased from 10.9 ± 3.0 to 30.9 ± 10.3 mU/L. There was a strong inverse correlation between the decrease in lipolysis and increase in insulin after glucagon administration. CONCLUSIONS. Infants who are born large for gestational age show increased lipolysis and a propensity for decreased insulin sensitivity already at birth. The simultaneous increase in plasma insulin correlated strongly with the noted decrease in lipolysis, indicating an antilipolytic effect of insulin in these infants.
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