RESUMEN
Ultrasonography, with its detailed imaging of the fetus, is very widely used in obstetrics. The primary aim of ultrasound scanning in pregnancy is to limit the risk of obstetric complications by early detection of abnormalities, such as intrauterine growth restriction and macrosomia. Currently, morphometric formulae are used for estimating fetal weight. They utilize basic biometric parameters. However, Hadlock formula, used for fetal weight estimation, has an error rate of 20%. For this reason, researchers all over the world have been looking for other sonographic parameters correlating with fetal weight, with a higher predictive value. The current scientific reports indicate that new sonographic parameters, such as soft tissue thickness values, are useful for fetal weight assessment. The measurements can be conducted in various parts of the fetus's body, e.g. thigh, upper arm, abdomen or the subscapular area. Different types of measurements are characterized by different levels of correlation with other sonographic and anthropometric parameters as well as body mass and gestational age. Based on the reports, numerous studies proposing new fetal weight calculation formulae have been produced. Apart from soft tissue, some more advanced and detailed measurements are taken, such as those involving adipose and lean tissue or using three-dimensional ultrasound (3D), for determining fetal weight. Ultrasound measurement of subcutaneous tissue thickness in various parts of the body may prove to be a strong predictor of fetal weight, which is useful for sonographic assessment of pregnancy.
RESUMEN
Mammalian hibernation involves periods of substantial suppression of metabolic rate (torpor) allowing energy conservation during winter. In thirteen-lined ground squirrels (Ictidomys tridecemlineatus), suppression of liver mitochondrial respiration during entrance into torpor occurs rapidly (within 2 h) before core body temperature falls below 30°C, whereas reversal of this suppression occurs slowly during arousal from torpor. We hypothesized that this pattern of rapid suppression in entrance and slow reversal during arousal was related to changes in the phosphorylation state of mitochondrial enzymes during torpor catalyzed by temperature-dependent kinases and phosphatases. We compared mitochondrial protein phosphorylation among hibernation metabolic states using immunoblot analyses and assessed how phosphorylation related to mitochondrial respiration rates. No proteins showed torpor-specific changes in phosphorylation, nor did phosphorylation state correlate with mitochondrial respiration. However, several proteins showed seasonal (summer vs. winter) differences in phosphorylation of threonine or serine residues. Using matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry, we identified three of these proteins: F1-ATPase α-chain, long chain-specific acyl-CoA dehydrogenase, and ornithine transcarbamylase. Therefore, we conclude that protein phosphorylation is likely a mechanism involved in bringing about seasonal changes in mitochondrial metabolism in hibernating ground squirrels, but it seems unlikely to play any role in acute suppression of mitochondrial metabolism during torpor.