23 research outputs found
Effects of 2-year physical activity and dietary intervention on adrenarchal and pubertal development: the PANIC study.
CONTEXT
Childhood overweight has been linked to earlier development of adrenarche and puberty, but it remains unknown if lifestyle interventions influence sexual maturation in general populations.
OBJECTIVE
To investigate if a 2-year lifestyle intervention influences circulating androgen concentrations and sexual maturation in a general population of children.
DESIGN AND PARTICIPANTS
A 2-year intervention study in which 421 prepubertal and mostly normal-weight 6-9-year-old children were allocated either to a lifestyle intervention group (119 girls, 132 boys) or a control group (84 girls, 86 boys).
INTERVENTION
A 2-year physical activity and dietary intervention.
MAIN OUTCOME MEASURES
Serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, and testosterone concentrations, and clinical adrenarchal and pubertal signs.
RESULTS
The intervention and control groups had no differences in body size and composition, clinical signs of androgen action, and serum androgens at baseline. The intervention attenuated the increase of dehydroepiandrosterone (p = 0.032), dehydroepiandrosterone sulfate (p = 0.001), androstenedione (p = 0.003), and testosterone (p = 0.007) and delayed pubarche (p = 0.038) in boys but it only attenuated the increase of dehydroepiandrosterone (p = 0.013) and dehydroepiandrosterone sulfate (p = 0.003) in girls. These effects of lifestyle intervention on androgens and the development of pubarche were independent of changes in body size and composition but the effects of intervention on androgens were partly explained by changes in fasting serum insulin.
CONCLUSIONS
A combined physical activity and dietary intervention attenuates the increase of serum androgen concentrations and sexual maturation in a general population of prepubertal and mostly normal-weight children, independently of changes in body size and composition
Intracellular calcium, preconditioning and regulation of cellular respiration in heart
Abstract
Heart muscle has to work constantly throughout the life and its energy metabolism is heavily dependent on a continuous supply of oxygen. Energy metabolism must be effectively regulated to meet the demands of changing workloads in different circumstances. If the oxygen supply is interrupted, the function of the heart is easily disturbed and cells injured. Calcium metabolism is of great importance in these pathological conditions.
In this thesis respiratory regulation was studied by non-destructive optical methods in mouse heart. The myoglobin-deficient mouse was used as an experimental model to avoid the artefact caused by intracellular myoglobin. Results show that increased consumption of energy and oxygen lead to concomitant reduction of cytochrome aa3 and oxidation of flavoproteins. This finding supports the view that cell respiration in intact myocardium is dominantly regulated at the level of the respiratory chain.
The intracellular Ca2+ accumulation during ischemia is one of the major causes of irreversible ischemia-reperfusion injury. Ischemic preconditioning (IPC) has been shown to protect the heart muscle significantly from ischemic damage. In this thesis Ca2+ accumulation during ischemia and reperfusion was studied in perfused rat heart using Fura-2 as a fluorescent Ca2+ indicator. As there is a significant decrease in intracellular pH during prolonged ischemia, the pH-dependency of Fura-2 signal was taken into account. It was found that IPC attenuates Ca2+accumulation during ischemia and this was connected to a decrease in mitochondrial membrane potential. Both IPC and the pharmacologically induced preconditioning with the mitoKATP opener diaxozide were shown to be associated with increased production of superoxide monitored by means of lucigenin chemiluminescence. The superoxide production correlated with the oxidation-reduction state of flavoproteins.
We also describe here a method for measuring of intracellular free Ca2+ in mouse heart during ischemia by simultaneous monitoring of Fura-2 and the pH probe BCECF fluorescence by means of dual wavelength excitation of both probes. The paradoxical decrease of Fura-2 fluorescence during ischemia indicating decreasing intracellular Ca2+ concentration was due to the pH effect on the dissociation constant of the Fura-2-Ca2+ complex. When the pH-dependency of Fura-2 was compensated, an extensive Ca2+ accumulation during ischemia was detected. Much of the previous literature on this subject must be re-evaluated because the pH-dependency of intracellular Ca2+ probes has been largely overlooked
Accelerated Early Childhood Growth Is Associated With the Development of Earlier Adrenarche and Puberty.
CONTEXT
Small birth size and increased postnatal growth have been associated with earlier timing of adrenarche and puberty, but it is not well known whether these factors alone or together lead to earlier maturation.
OBJECTIVE
This work aimed to search for different growth trajectories using a clustering approach to analyze the effects of birth size and postnatal growth on adrenarchal and pubertal development.
METHODS
Altogether 351 children (48% girls) were examined prospectively at ages 6 to 9 and 9 to 11 years. Birth and early-growth data were collected retrospectively. Main outcome measures included clinical signs of adrenarche and puberty, and serum androgen concentrations (dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione, testosterone).
RESULTS
We detected 4 clusters with different birth sizes and postnatal growth trajectories: 1) children with average birth size and increased postnatal growth (AI), 2) children with small birth size and increased postnatal growth (SI), 3) children with average birth size and postnatal growth (AA), and 4) children with small birth size and average postnatal growth (SA). Thelarche at age 9 to 11 was most common and serum androgens at ages 6 to 9 and 9 to 11 years were highest in girls belonging to the AI and SI groups. Similar patterns in the onset of puberty and in androgen levels were not seen in the SA group.
CONCLUSION
Increased early growth and weight gain predict higher serum androgen concentrations and earlier onset of puberty in girls. Adrenarche and puberty do not appear to be shifted earlier in children with small birth size who do not have catch-up growth
Adrenal Abcg1 controls cholesterol flux and steroidogenesis.
Cholesterol is the precursor of all steroids, but how cholesterol flux is controlled in steroidogenic tissues is poorly understood. The cholesterol exporter ABCG1 is an essential component of the reverse cholesterol pathway and its global inactivation results in neutral lipid redistribution to tissue macrophages. The function of ABCG1 in steroidogenic tissues, however, has not been explored. To model this, we inactivated Abcg1 in the mouse adrenal cortex, which led to an adrenal-specific increase in transcripts involved in cholesterol uptake and de novo synthesis. Abcg1 inactivation did not affect adrenal cholesterol content, zonation, or serum lipid profile. Instead, we observed a moderate increase in corticosterone production that was not recapitulated by the inactivation of the functionally similar cholesterol exporter Abca1. Altogether, our data imply that Abcg1 controls cholesterol uptake and biosynthesis and regulates glucocorticoid production in the adrenal cortex, introducing the possibility that ABCG1 variants may account for physiological or subclinical variation in stress response
Effects of 2-Year Physical Activity and Dietary Intervention on Adrenarchal and Pubertal Development: The PANIC Study
Accelerated Early Childhood Growth Is Associated With the Development of Earlier Adrenarche and Puberty
An experimental study on the improvement of mixture distribution for the automotive S.I. Engines
Translating the IHE Teaching File and Clinical Trial Export (TCE) Profile Document Templates into Functional DICOM Structured Report Objects
The Integrating the Healthcare Enterprise (IHE) Teaching File and Clinical Trial Export (TCE) integration profile describes a standard workflow for exporting key images from an image manager/archive to a teaching file, clinical trial, or electronic publication application. Two specific digital imaging and communication in medicine (DICOM) structured reports (SR) reference the key images and contain associated case information. This paper presents step-by-step instructions for translating the TCE document templates into functional and complete DICOM SR objects. Others will benefit from these instructions in developing TCE compliant applications
Figure S1.docx
Cholesterol is the precursor of all steroids, but how cholesterol flux is controlled in steroidogenic tissues is poorly understood. The cholesterol exporter ABCG1 is an essential component of the reverse cholesterol pathway and its systemic inactivation results in neutral lipid redistribution to macrophages. However, the function of ABCG1 in steroidogenic organs is not explored. To model this question, we inactivated the ortholog Abcg1 gene in the mouse adrenal cortex. Abcg1 disruption led to an adrenal-specific increase in transcripts involved in cholesterol uptake and de novo synthesis, and to an 80% increase in corticosterone production. Importantly, this phenotype was not recapitulated by inactivation of the cholesterol exporter Abca1. In addition, Abcg1 disruption did not affect blood lipid profile. Altogether, our data indicate that adrenal Abcg1 controls cholesterol uptake and biosynthesis, and regulates glucocorticoid production.</p
Overexpression of Vascular Endothelial Growth Factor-B in Mouse Heart Alters Cardiac Lipid Metabolism and Induces Myocardial Hypertrophy
Vascular Endothelial Growth Factor-B (VEGF-B) is poorly angiogenic but prominently expressed in metabolically highly active tissues, including the heart. We produced mice expressing a cardiac-specific VEGF-B transgene via the alpha myosin heavy chain promoter. Surprisingly, the hearts of the VEGF-B transgenic mice showed concentric cardiac hypertrophy without significant changes in heart function. The cardiac hypertrophy was due to an increased size of the cardiomyocytes. Blood capillary size was increased, while the number of blood vessels per cell nucleus remained unchanged. Despite the cardiac hypertrophy, the transgenic mice had lower heart rate and blood pressure than their littermates, and they responded similarly to angiotensin II-induced hypertension, confirming that the hypertrophy does not compromise heart function. Interestingly, the isolated transgenic hearts had less cardiomyocyte damage after ischemia. Significantly increased ceramide and decreased triglyceride levels were found in the transgenic hearts. This was associated with structural changes and eventual lysis of mitochondria, resulting in accumulation of intracellular vacuoles in cardiomyocytes and increased death of the transgenic mice, apparently due to mitochondrial lipotoxicity in the heart. These results suggest that VEGF-B regulates lipid metabolism, an unexpected function for an angiogenic growth factor