The aim of the current study is to analyze the interaction of the muscle and bone system (muscle-bone unit) during puberty in males and females by computed tomography of the nondominant forearm. The data presented here are the first results from 318 healthy children (159 boys and 159 girls), aged 6-22 yr, and 336 adults (parents) participating in the DONALD Study (Dortmund Nutritional and Anthropometric Longitudinally Designed Study). Cortical area (CA) of the radius representing bone strength and muscle area (MA) representing muscle strength were measured with peripheral quantitative computed tomography (XCT 2000; Stratec, Pforzheim, Germany). A single slice measurement at a site corresponding to 65% of the ulnar length proximal to the radial endplate was used. MA and CA of the radius have been determined by a built-in software algorithm using density differences. There was a strong correlation between MA (x) and CA (y) in all children, adolescents, and adults (y = 0.019x + 10.93; r2 = 0.77). Before puberty, boys and girls displayed a similar relation between MA and CA. CA in relation to MA was greater in girls than in boys during puberty. Analysis of covariance was performed investigating the dependency of CA on MA, five pubertal stages, sex, and interaction of sex and pubertal stages. MA representing muscle strength was the strongest predictor of CA (P < 0.001) representing bone mass. Pubertal stage (P < 0.001) and interaction of pubertal stage*sex (P = 0.002) also had a significant influence on CA. r2 of the model was 0.85. These data suggest that in pubertal girls and women rather than in pubertal boys and men an additional factor shifts the relationship between MA and CA to higher values of cortical area. The present data confirm previous studies of the influence of puberty and estrogens or related factors on the muscle-bone interaction.

Recent studies suggest that the perinatal period is a sensitive part in human development with respect to the pathogenesis of metabolic diseases in adulthood. Neonates, who are either small or large for gestational age (SGA or LGA) have a greater risk of developing obesity and insulin resistance in later life. The term "perinatal priming" is used to describe this phenomenon. Therefore, in the present study we first aimed to investigate if birth weight influences fetal adiponectin and RBP-4 metabolism. Umbilical cord blood was obtained form 40 neonates born on term+/-4 weeks and the adipokine concentrations in the serum were measured. In this analysis adiponectin but not RBP-4 levels showed a positive significant correlation to birth weight. Since maternal preconceptional obesity is associated with an increased birth weight and the risk for LGA neonates, we further aimed to investigate, if the maternal nutritional state influences fetal adiponectin and RBP-4. Therefore umbilical cord blood levels of the adipokines were correlated to maternal preconceptional BMI. In this analysis, neither adiponectin nor RBP-4 levels showed a significant correlation. Taken together, in the present study for the first time we directly compare fetal adiponectin and RBP-4 levels in respect to birth weight and maternal preconceptional BMI. Our data suggest that (1) adiponectin is more likely to have a role in perinatal priming of obesity and insulin resistance than RBP-4 and (2) that birth weight has a greater impact on fetal adipokine serum levels than maternal preconceptional obesity.

To test the functioning of circadian rhythms removed from periodicities of the earth's 24-hour rotation, the conidiation rhythm of the fungus Neurospora crassa was monitored in constant darkness during spaceflight. The free-running period of the rhythm was the same in space as on the earth, but there was a marked reduction in the clarity of the rhythm, and apparent arrhythmicity in some tubes. At the current stage of analysis of our results there is insufficient evidence to determine whether the effect seen in space was related to removal from 24-hour periodicities and whether the circadian timekeeping mechanism, or merely its expression, was affected.

The authors examined the "aftereffects" of entrainment of Bulla gouldiana to 11 h light:11 h dark (LD 11:11) (T22) or LD 13:13 (T26) on the period (tau) of the circadian rhythm of impulse activity recorded in vitro from the eye in constant darkness. When both eyes remained attached to the cerebral ganglion, the average period was 23.9 +/- 0.62 h (mean +/- SD, n = 6) for animals from T22 and 24.9 +/- 0.54 h for animals from T26. The 1-h difference between the periods of the T26 and the T22 animals was significant (p < .01, t test). When eyes were isolated from the cerebral ganglion by severing the optic nerve, the difference in average period between eyes from T22 and eyes from T26 animals was 2.2 h (23.3 +/- 0.72 h [n = 7] vs. 25.5 +/- 0.62 [n = 6], p < .001). When eyes remained attached to the brain but uncoupled from the contralateral eye, the aftereffect of entrainment to non-24-h light cycles was intermediate. For T22 animals, tau was 23.9 +/- 0.29 h (n = 6), whereas for the T26 animals, tau = 25.2 +/- 0.48 h (n = 7). The results show that isolated eyes can express aftereffects and indicate that coupling between ocular pacemakers and efferent signals from the cerebral ganglion diminish the effects of entrainment on the free-running period of the rhythm from the eye.

The sections in this article are: Daily Rhythms Models and Mechanisms Circadian Pacemaking Systems in Invertebrates Pacemakers in the Arthropod Brain Circadian Pacemakers Outside the Nervous System in Insects Pacemakers in the Gastropod Retina Multioscillator Organization Identification of Output Pathways Circadian Pacemaking Systems in Vertebrates The Mammalian SCN Other Circadian Oscillators in Mammals Hypothalamic Regulation of Circadian Function in Nonmammalian Vertebrates The Pineal Organ Eyes as Clocks Photoreceptor Localization and Mechanisms of Entrainment in Invertebrates Photoreceptive Input: Invertebrates Mechanisms of Regulation of Pacemaker Phase Photoreceptor Localization and Mechanisms of Entrainment in Vertebrates Identification of Photoreceptors Mechanisms of Regulation of Pacemaker Phase Seasonality in Invertebrates Modes of Seasonality Timing of Seasonal Cycles Photoperiodic Time Measurement Mechanisms of Photoperiodic Time Measurement The Photoperiodic Timer The Photoperiodic Counter Anatomical Location of Timers and Counters Photoreceptors Circannual Rhythms Seasonality in Vertebrates Photoperiodic Time Measurement: Models and Experimental Validation Physiological Mechanisms The Pineal and Melatonin: Mammals Mechanisms of Pineal Action The Pineal and Melatonin: Nonmammalian Vertebrates Photoreceptive Inputs: Mammalian Photoreceptive Inputs: Nonmammalian Maternal–Fetal Transfer of Photoperiodic Information Circannual Rhythms Physiological Mechanisms Concluding Comments