scholarly journals Genetic Influences on Hormonal Markers of Chronic HPA Function in Human Hair

2016 ◽  
Author(s):  
Elliot M. Tucker-Drob ◽  
Andrew Grotzinger ◽  
Daniel A. Briley ◽  
Laura E. Engelhardt ◽  
Frank D. Mann ◽  
...  
Keyword(s):  
Human Hair ◽  
Environmental Influences ◽  
Genetic Influences ◽  
Hair Cortisol ◽  
Family Socioeconomic Status ◽  
Biological Stress ◽  
Hair Samples ◽  
Inactive Metabolite ◽  
Primary Output ◽  
Adolescent Twins

AbstractCortisol is the primary output of the hypothalamic-pituitary-adrenal (HPA) axis and is central to the human biological stress response, with wide-ranging effects on physiological function and psychiatric health. In both humans and animals, cortisol is frequently studied as a biomarker for exposure to environmental stress. Relatively little attention has been paid to the possible role of genetic variation in heterogeneity in chronic cortisol, in spite of well-studied biological pathways of glucocorticoid function. Using recently developed technology, hair samples can now be used to measure accumulation of cortisol over several months. In contrast to more conventional salivary measures, hair cortisol is not influenced by diurnal variation or transient hormonal reactivity. In an ethnically and socioeconomically diverse sample of 1 070 child and adolescent twins and multiples from 556 unique families, we estimated genetic and environmental influences on hair concentrations of cortisol and its inactive metabolite, cortisone. We identified sizable genetic influences on cortisol that decrease with age, concomitant with genetic influences on cortisone that increase with age. Shared environmental influences on cortisol and cortisone were modest and, for cortisol, decreased with age. Twin-specific, non-shared environmental contributions to cortisol and cortisone became increasingly correlated with age. We find some evidence for sex differences in the biometric contributions to cortisol, but no strong evidence for main or moderating effects of family socioeconomic status on cortisol or cortisone. This study constitutes the first genetic study of hormone concentrations in human hair, and provides the most definitive characterization to-date of age and socioeconomic influences on hair cortisol.

scholarly journals Genetic and Environmental Influences on Pubertal Hormones in Human Hair across Development

2017 ◽  
Author(s):  
Andrew D. Grotzinger ◽  
Daniel A. Briley ◽  
Laura E. Engelhardt ◽  
Frank D. Mann ◽  
Megan W. Patterson ◽  
...  
Keyword(s):  
Human Hair ◽  
Environmental Influences ◽  
Childhood And Adolescence ◽  
Genetic Studies ◽  
Medical Disorders ◽  
Quantitative Genetic ◽  
Hair Samples ◽  
Males And Females ◽  
Adolescent Twins ◽  
Developmental Windows

AbstractBackground: Puberty is a complex biopsychosocial process that is linked to an array of psychiatric and medical disorders that emerge in adolescence and persist across the lifespan. Although the pubertal process is driven by neuroendocrine changes, few quantitative genetic studies have directly measured puberty-relevant hormones. Hair samples can now be assayed for accumulation of hormones over several months. In contrast to more conventional salivary measures, hair measures are not confounded by diurnal variation or hormonal reactivity.Methods: In an ethnically and socioeconomically diverse sample of 1,286 child and adolescent twins and multiples from 672 unique families, we estimated genetic and environmental influences on concentrations of testosterone, DHEA, and progesterone in hair across the period of 8 to 18 years of age.Results: We identified sex-specific developmental windows of maximal heritability in each hormone. Peak heritability for DHEA occurred at age 9.8 years for males and 10.0 years for females. Peak heritability for testosterone occurred at age 12.5 and 15.2 years for males and females, respectively. Peak heritability for male progesterone occurred at 11.2 years, while the heritability of female progesterone remained uniformly low.Conclusion: This is the first study of genetic influences on pubertal hormone concentrations in human hair and is the largest of the heritability of pubertal hormones in any form. The identification of specific developmental windows when genetic signals for hormones are maximized has critical implications for well-informed models of hormone-behavior associations in childhood and adolescence.

scholarly journals Genetic Influences on Respiratory Sinus Arrhythmia across Different Task Conditions

1990 ◽  
Vol 39 (2) ◽  
pp. 181-191 ◽  
Author(s):  
D.I. Boomsma ◽  
G.C.M. van Baal ◽  
J.F. Orlebeke
Keyword(s):  
Respiratory Sinus Arrhythmia ◽  
Genetic Variance ◽  
Factor Model ◽  
Environmental Influences ◽  
Genetic Influences ◽  
Environmental Variance ◽  
Sinus Arrhythmia ◽  
Task Conditions ◽  
Adolescent Twins ◽  
And Task

AbstractRespiratory sinus arrhythmia (RSA) has been shown to be a sensitive index of vagal cardiac control. We studied the genetic and nongenetic influences on individual differences in RSA in a sample of 160 adolescent twins. RSA was measured during rest and across two different tasks. Results show that heritability is task dependent. The amount of genetic variance is the same, however, during rest and task conditions. Because nonshared environmental variance decreases during tasks, heritability is larger for RSA measured under more stressful conditions than for RSA as measured during rest. Multivariate models assessed the continuity of the genetic and environmental influences and show genetic influences to be the same across different conditions, while environmental influences are different. More specifically, a one-factor model is found for genetic influences and a second-order autoregressive model for the environmental factors.

Human-hair analysis

1992 ◽  
Vol 50 (1) ◽  
pp. 886-887
Author(s):  
Brenda E. Lambert ◽  
Ernest C. Hammond
Keyword(s):  
Human Hair ◽  
Hair Analysis ◽  
Hair Shaft ◽  
White Female ◽  
Chemical Processing ◽  
X Ray ◽  
Hair Samples ◽  
Wave Technique ◽  
Permanent Wave ◽  
Scanning Electron

The purpose of this study was to examine the external structure of four human hair shaft samples with the scanning Electron Microscope (SEM) and to obtain information regarding the chemical composition of hair by using the attached x ray microanalysis unit.The hair samples were obtained from two female subjects. Sample A was taken from a black female and had not undergone any type of chemical processing. Sample B, C, D were taken from a white female, and were natural, processed, and unpigmented, i.e. “gray”, respectively. Sample C had been bleached, tinted, and chemically altered using a permanent wave technique.

Plant Oil-Based Nanoemulsions: Preparation and Efficacy for Hair Treatment

2020 ◽  
Vol 04 ◽  
Author(s):  
Lívia Gonçalves Ferreira Rodrigues ◽  
Juliana Falcão Alves de Carvalho ◽  
Cristal dos Santos Cerqueira Pinto ◽  
Elisabete Pereira Santos ◽  
Claudia Regina Elias Mansur
Keyword(s):  
Human Hair ◽  
Mechanical Tests ◽  
Plant Oils ◽  
Plant Oil ◽  
Oil In Water ◽  
Hair Samples ◽  
Poly Ethylene Oxide ◽  
Treatment Objective ◽  
Poly Ethylene ◽  
Average Size

Background:: The use of polymers in hair care products is widespread, and silicones in particular are extensively used in cosmetic formulations. In addition, plant oils can also be used for hair treatment. Objective: In the present work, oil-in-water (O/W) nanoemulsions were prepared to repair chemical damage to human hair samples, to investigate the combined use of a silicone polyether copolymer (surfactant) that has a branch composed of poly(ethylene oxide) in its chains, and two types of plant oils: coconut and ojon oil. Materials and Methods:: Surfactant-oil-water formulations were obtained by ultrasonic processing. The nanoemulsions were then applied to human hair strands previously damaged with sodium hydroxide, to compare the treated strands with untreated ones. The efficacy of the formulations was investigated by scanning electron microscopy, thermogravimetric analysis and mechanical tests. Results and Discussion:: Stables nanoemulsions were obtained with average size of the dispersed droplets up to 400 nm. The micrographs suggest that the action mechanism of the nanoemulsions depends not only on the type of plant oil used and size of the droplets dispersed in the system, but also on the type of hair that receives the treatment. The thermal analysis showed that the use of nanoemulsion changed the temperature of keratin interconversion to higher values, which can make hair fibers more resistant to heat. Hair resistance was improved when comparing virgin samples to the damaged ones. Conclusion:: The nanoemulsions were efficient in the treatment of the hair samples, which showed a significant improvement of their mechanical properties.

scholarly journals Hair cortisol levels in pregnancy as a possible determinant of fetal sex: a longitudinal study

2021 ◽  
pp. 1-6
Author(s):  
Borja Romero-Gonzalez ◽  
Jose A. Puertas-Gonzalez ◽  
Raquel Gonzalez-Perez ◽  
Marta Davila ◽  
Maria Isabel Peralta-Ramirez
Keyword(s):  
Low Birthweight ◽  
First Trimester ◽  
Hair Cortisol ◽  
Negative Results ◽  
Stress Vulnerability ◽  
Biological Stress ◽  
First Trimester Of Pregnancy ◽  
Prenatal Distress ◽  
Cortisol Levels ◽  
The Relationship

Abstract Stress during pregnancy has been widely studied and associated to different variables, usually with negative results for the health of the mother and the newborn, such as having a higher risk of suffering postpartum depression, premature birth, obstetrics complications or low birthweight, among others. However, there are not many lines of research that study the role that the sex of the baby plays on this specific stress and vice versa. Thus, the main objective was to analyse the relationship between the sex of the offspring and the stress of the mothers in the first trimester of pregnancy. In order to achieve this, 108 women had their biological stress measured (trough hair cortisol levels) and psychological stress evaluated (the Prenatal Distress Questionnaire (PSS), the Perceived Stress Scale (PDQ) and the Stress Vulnerability Inventory (IVE)). The results revealed significant differences in maternal hair cortisol levels in the first trimester based on the sex of the baby they had given birth to (t = −2.04; P < 0.05): the concentration of the hormone was higher if the baby was a girl (164.36:54.45-284.87 pg/mg) than if it was a boy (101.13:37.95-193.56 pg/mg). These findings show that the sex of the future baby could be conditioned, among many other variables, by the mother´s stress levels during conception and first weeks of pregnancy. Further research is needed in this area to support our findings.

scholarly journals Genetic Influences on the Covariance and Genetic Correlations in a Bivariate Twin Model: An Application to Well-Being

2021 ◽  
Author(s):  
Lianne P. de Vries ◽  
Toos C. E. M. van Beijsterveldt ◽  
Hermine Maes ◽  
Lucía Colodro-Conde ◽  
Meike Bartels
Keyword(s):  
Complex Traits ◽  
Educational Achievement ◽  
Genetic Correlations ◽  
Well Being ◽  
Genetic Influences ◽  
Phenotypic Correlation ◽  
Twin Model ◽  
Twin Models ◽  
Adolescent Twins ◽  
Depressed Symptoms

AbstractThe distinction between genetic influences on the covariance (or bivariate heritability) and genetic correlations in bivariate twin models is often not well-understood or only one is reported while the results show distinctive information about the relation between traits. We applied bivariate twin models in a large sample of adolescent twins, to disentangle the association between well-being (WB) and four complex traits (optimism, anxious-depressed symptoms (AD), aggressive behaviour (AGG), and educational achievement (EA)). Optimism and AD showed respectively a strong positive and negative phenotypic correlation with WB, the negative correlation of WB and AGG is lower and the correlation with EA is nearly zero. All four traits showed a large genetic contribution to the covariance with well-being. The genetic correlations of well-being with optimism and AD are strong and smaller for AGG and EA. We used the results of the models to explain what information is retrieved based on the bivariate heritability versus the genetic correlations and the (clinical) implications.

scholarly journals Determination of Vitamin B3 Vitamer (Nicotinamide) and Vitamin B6 Vitamers in Human Hair Using LC-MS/MS

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4487
Author(s):  
Sundus M. Sallabi ◽  
Aishah Alhmoudi ◽  
Manal Alshekaili ◽  
Iltaf Shah
Keyword(s):  
Human Hair ◽  
Vitamin B6 ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Reversed Phase ◽  
Water Soluble ◽  
Vitamin B3 ◽  
Hair Samples ◽  
Pyridoxal Hydrochloride ◽  
Vitamin B3 Deficiency

Water-soluble B vitamins participate in numerous crucial metabolic reactions and are critical for maintaining our health. Vitamin B deficiencies cause many different types of diseases, such as dementia, anaemia, cardiovascular disease, neural tube defects, Crohn’s disease, celiac disease, and HIV. Vitamin B3 deficiency is linked to pellagra and cancer, while niacin (or nicotinic acid) lowers low-density lipoprotein (LDL) and triglycerides in the blood and increases high-density lipoprotein (HDL). A highly sensitive and robust liquid chromatography–tandem mass spectroscopy (LC/MS-MS) method was developed to detect and quantify a vitamin B3 vitamer (nicotinamide) and vitamin B6 vitamers (pyridoxial 5′-phosphate (PLP), pyridoxal hydrochloride (PL), pyridoxamine dihydrochloride (PM), pridoxamine-5′-phosphate (PMP), and pyridoxine hydrochloride (PN)) in human hair samples of the UAE population. Forty students’ volunteers took part in the study and donated their hair samples. The analytes were extracted and then separated using a reversed-phase Poroshell EC-C18 column, eluted using two mobile phases, and quantified using LC/MS-MS system. The method was validated in human hair using parameters such as linearity, intra- and inter-day accuracy, and precision and recovery. The method was then used to detect vitamin B3 and B6 vitamers in the human hair samples. Of all the vitamin B3 and B6 vitamers tested, only nicotinamide was detected and quantified in human hair. Of the 40 samples analysed, 12 were in the range 100–200 pg/mg, 15 in the range 200–500 pg/mg, 9 in the range of 500–4000 pg/mg. The LC/MS-MS method is effective, sensitive, and robust for the detection of vitamin B3 and its vitamer nicotinamide in human hair samples. This developed hair test can be used in clinical examination to complement blood and urine tests for the long-term deficiency, detection, and quantification of nicotinamide.

scholarly journals WHY DO PEOPLE DIFFER IN THEIR ACHIEVEMENT MOTIVATION? A NUCLEAR TWIN FAMILY STUDY

2019 ◽  
Vol 11 (4) ◽  
pp. 433-450 ◽  
Author(s):  
Lea Klassen ◽  
Eike F. Eifler ◽  
Anke Hufer ◽  
Rainer Riemann
Keyword(s):  
Achievement Motivation ◽  
School Environment ◽  
Environmental Influences ◽  
Twin Studies ◽  
Genetic Influences ◽  
Parental Home ◽  
Nationally Representative ◽  
The Impact ◽  
Home And School

Although many previous studies have emphasized the role of environmental factors, such as parental home and school environment, on achievement motivation, classical twin studies suggest that both additive genetic influences and non-shared environmental influences explain interindividual differences in achievement motivation. By applying a Nuclear Twin Family Design on the data of the German nationally representative of TwinLife study, we analyzed genetic and environmental influences on achievement motivation in adolescents and young adults. As expected, the results provided evidence for the impact of additive genetic variation, non-additive genetic influences, as well as twin specific shared environmental influences. The largest amount of variance was attributed to non-shared environmental influences, showing the importance of individual experiences in forming differences in achievement motivation. Overall, we suggest a revision of models and theories that explain variation in achievement motivation by differences in familial socialization only.

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