Publications by authors named "Veldhuis J"

Article Synopsis
  • Previous research on cosmetic surgery acceptance has mainly focused on adult females, highlighting the need for qualitative studies on adolescents, who are increasingly becoming the next demographic for cosmetic procedures.
  • This study comprises 13 focus groups with 42 adolescents, analyzing their attitudes and intentions regarding cosmetic procedures through reflexive thematic analysis, resulting in five key themes.
  • The themes include sources of information about cosmetic procedures, the normalization of the cosmetic industry, varied attitudes towards these procedures, intentions to undergo them, and the construction of 'the cosmetic consumer,' illustrating how adolescents perceive and relate to the cosmetic surgery landscape.
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Objective: Evaluating the safety of a more expectative approach than described in the guideline 'Mild traumatic head/brain injury' (mTBI) within children.

Design: Retrospective chart review.

Method: Children (0-18 years) with mTBI, who visited the emergency department of Isala between December 2018 and July 2022, were included.

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The hypothalamus is the central regulator of reproductive hormone secretion. Pulsatile secretion of gonadotropin releasing hormone (GnRH) is fundamental to physiological stimulation of the pituitary gland to release luteinizing hormone (LH) and follicle stimulating hormone (FSH). Furthermore, GnRH pulsatility is altered in common reproductive disorders such as polycystic ovary syndrome (PCOS) and hypothalamic amenorrhea (HA).

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Studies investigating motives for social networking sites (SNS) use amongst people with eating disorder (ED) symptoms are scarce. The uses and gratifications theory states that people actively select media content to gratify their individual needs and this may help to explain why individuals with eating disorder symptoms choose to expose themselves to specific media content and how they choose to respond. Some evidence exists that readiness to change may be a factor related to SNS use patterns in this population.

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Article Synopsis
  • Young people are heavily influenced by appearance-focused content on social media, particularly Instagram, which shapes their perceptions of cosmetic surgery.
  • In a study of 470 Instagram users aged 18-25, participants showed a low intention to undergo cosmetic procedures but believed that many others had.
  • Following influencers who have had cosmetic procedures increased intentions to undergo similar procedures, while using filters on selfies correlated with a higher acceptance of cosmetic surgery.
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Background: Many hormones display distinct circadian rhythms, driven by central regulators, hormonal bioavailability, and half-life. A set of 11-oxygenated C19 steroids (11-oxyandrogens) and pregnenolone sulfate (PregS) are elevated in congenital adrenal hyperplasia and other disorders, but their circadian patterns have not been characterized.

Participants And Methods: Peripheral blood was collected every 2 h over 24 h from healthy volunteer men (10 young, 18-30 years, and 10 older, 60-80 years).

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Context: Interleukin-2 (IL-2), a proinflammatory cytokine, has been used to treat malignancies. Increased cortisol and adrenocorticotropin (ACTH) were noted, but growth hormone (GH) secretion was not investigated in detail.

Objective: We quantified GH secretion after a single subcutaneous injection of IL-2 in 17 young and 18 older healthy men in relation to dose, age, and body composition.

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The well-balanced secretion between insulin and growth hormone (GH) is essential in regulating substrate metabolism, energy metabolism, and body composition. High insulin and low GH levels are often observed in obesity, contributing to reduced energy expenditure and further fat accumulation. Although suppression of hyperinsulinemia is proposed as a treatment for obesity, changes in GH secretion and energy metabolism following this treatment are not thoroughly studied.

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Context: Sleep loss in men increases cortisol and decreases testosterone, and sleep restriction by 3 to 4 hours/night induces insulin resistance.

Objective: We clamped cortisol and testosterone and determined the effect on insulin resistance.

Methods: This was a randomized double-blind, in-laboratory crossover study in which 34 healthy young men underwent 4 nights of sleep restriction of 4 hours/night under 2 treatment conditions in random order: dual hormone clamp (cortisol and testosterone fixed), or matching placebo (cortisol and testosterone not fixed).

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Introduction: While the vast majority of research investigating the role of ghrelin or its receptor, GHS-R1a, in growth, feeding, and metabolism has been conducted in male rodents, very little is known about sex differences in this system. Furthermore, the role of GHS-R1a signaling in the control of pulsatile GH secretion and its link with growth or metabolic parameters has never been characterized.

Methods: We assessed the sex-specific contribution of GHS-R1a signaling in the activity of the GH/IGF-1 axis, metabolic parameters, and feeding behavior in adolescent (5-6 weeks old) or adult (10-19 weeks old) GHS-R KO (Ghsr-/-) and WT (Ghsr+/+) male and female mice.

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Obese individuals often show low growth hormone (GH) secretion, which leads to reduced lipid mobilization and further fat accumulation. Pharmacological approaches to increase GH levels in obese individuals by GH injection or GH-releasing hormone receptor agonist showed promising effects on fat reduction. However, side effects on glucose metabolism and the heavy costs on making large peptides hindered their clinical application.

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Background: Interleukin-2 (IL-2), one of the proinflammatory cytokines, is used in the treatment of certain malignancies. In some studies, transient increases in cortisol and ACTH secretion occurred. Thus, this agent may be used as an experimental probe of adrenal cortisol secretion.

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Study Question: What is the role of the hypothalamic neuropeptide neurokinin B (NKB) and its interaction with kisspeptin on GnRH/LH secretion in women with polycystic ovary syndrome (PCOS)?

Summary Answer: Administration of neurokinin 3 receptor antagonist (NK3Ra) for 7 days reduced LH and FSH secretion and LH pulse frequency in women with PCOS, whilst the stimulatory LH response to kisspeptin-10 was maintained.

What Is Known Already: PCOS is characterized by abnormal GnRH/LH secretion. NKB and kisspeptin are master regulators of GnRH/LH secretion, but their role in PCOS is unclear.

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Background: Neurokinin 3 receptor (NK3R) antagonism is a promising novel treatment for menopausal flashes. However, to avoid adverse hormonal effects it is clinically important to first confirm whether gonadotropin and estradiol concentrations change as a result of their administration.

Methods: Single-center, randomized, double-blind, placebo-controlled, crossover trial of an oral NK3R antagonist (MLE4901) in 28 women aged 40 to 62 years, experiencing >7 hot flashes/24 h; some bothersome or severe (Clinicaltrials.

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Context: Glucagon increases energy expenditure; consequently, glucagon receptor agonists are in development for the treatment of obesity. Obesity negatively affects the reproductive axis, and hypogonadism itself can exacerbate weight gain. Therefore, knowledge of the effects of glucagon receptor agonism on reproductive hormones is important for developing therapeutics for obesity; but reports in the literature about the effects of glucagon receptor agonism on the reproductive axis are conflicting.

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Circulating growth hormone (GH) concentrations increase during pregnancy in mice and remain pituitary-derived. Whether abundance or activation of the GH secretagogue ghrelin increase during pregnancy, or in response to dietary octanoic acid supplementation, is unclear. We therefore measured circulating GH profiles in late pregnant C57BL/6J mice and in aged-matched non-pregnant females fed with standard laboratory chow supplemented with 5% octanoic or palmitic (control) acid (n = 4-13/group).

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Context: Glucagon-like peptide-1 (GLP-1) potently reduces food intake and augments glucose-stimulated insulin secretion. Recent animal data suggest that GLP-1 may also influence reproduction. As GLP-1 receptor agonists are currently widely used in clinical practice to treat obesity/type 2 diabetes, it is necessary to determine the effects of GLP-1 on the reproductive system in humans.

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Study Objectives: In young men, sleep restriction decreases testosterone (Te) and increases afternoon cortisol (F), leading to anabolic-catabolic imbalance, insulin resistance, and other andrological health consequences. Age-related differences in the hypothalamo-pituitary-testicular/adrenal response to sleep restriction could expose older individuals to greater or lesser risk. We aimed to evaluate and compare the 24-h and time-of-day effect of sleep restriction on F, luteinizing hormone (LH), and Te in young and older men.

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The well-documented hormonal disturbance in a general obese population is characterised by an increase in insulin secretion and a decrease in growth hormone (GH) secretion. Such hormonal disturbance promotes an increase in fat mass, which deteriorates obesity and accelerates the development of insulin resistance and type 2 diabetes. While the pathological consequence is alarming, the pharmaceutical approach attempting to correct such hormonal disturbance remains limited.

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Background: Aging is associated with diminished testosterone (Te) secretion, which may be attributed to Leydig cell dysfunction, decreased pituitary stimulation, and altered Te feedback.

Objective: To study all regulatory nodes-gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and Leydig cell-in the same cohort of healthy men.

Study Design: This was a placebo-controlled, blinded, prospectively randomized cross-over study in 40 men, age range 19 to 73 years, and body mass index (BMI) range 20 to 34.

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As a model of extreme conditions, eight healthy women, part of a 40-member Nepal mountain-climbing expedition, were monitored for dynamic endocrine adaptations. Endocrine measurements were made at frequent intervals over a 6-10-h period at four altitudes: 450 m, 4,800 m (base camp), 6,050 m, and again at 4,800 m (on descent) after an acclimatization (A) period (4,800 mA). Quantified hormones were growth hormone (GH), prolactin (PROL), cortisol (Cort), thyroid-stimulating hormone (TSH), and free thyroxine.

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Article Synopsis
  • * Conducted as a single-blind, randomized, placebo-controlled crossover trial, 18 healthy men received either PYY or a placebo through an eight-hour intravenous infusion.
  • * Results showed no significant differences in luteinizing hormone (LH) pulses, levels of LH, follicle stimulating hormone (FSH), or testosterone between the PYY and placebo infusions, suggesting PYY does not affect the reproductive axis in this population.
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During Drosophila embryogenesis, the germband first extends to curl around the posterior end of the embryo and then retracts back; however, retraction is not simply the reversal of extension. At a tissue level, extension is coincident with ventral furrow formation, and at a cellular level, extension occurs via convergent cell neighbor exchanges in the germband, whereas retraction involves only changes in cell shape. To understand how cell shapes, tissue organization, and cellular forces drive germband retraction, we investigate this process using a whole-embryo, surface-wrapped cellular finite-element model.

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Article Synopsis
  • The study explores the relationship between menopausal hot flushes (HFs) and LH hormone pulses, focusing on the role of hypothalamic KNDy neurones.
  • Eleven menopausal women were monitored over an 8-hour period, reporting HFs and undergoing blood sampling to analyze LH pulsatility using advanced mathematical models.
  • The findings indicate a low likelihood of synchronization between HFs and LH pulses, suggesting that the established belief of their consistent correlation may need reevaluation and has significant implications for treatment approaches.
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