Influence of perinatal factors on the onset of puberty in boys and girls: implications for interpretation of link with risk of long term diseases.

The authors examined the hypothesis that perinatal factors influence the onset of puberty. Children born as singletons in Uppsala, Sweden, in 1973-1977 were followed for height development before and during their school years (through 16 years of age). In all, 62 children born after preeclampsia, 129 born prematurely, 90 born small for gestational age, 175 born large for gestational age, 49 born short for gestational age, and 38 born tall for gestational age were compared with 688 "normal" children. Differences in age and height at puberty onset and age at menarche were analyzed using the t test and analyses of covariance. For boys, the mean age at puberty onset did not differ between normal boys and those with perinatal factors. Boys born small or short for gestational age were 4 cm shorter than normal boys, and those born large for gestational age were 3 cm taller than normal boys. Among girls, patterns for differences in height were similar. Girls born small for gestational age were 5 months younger than normal girls at the onset of puberty and menarche. Patterns of early childhood growth seemed to explain the relations between these perinatal factors and height and age at puberty. The authors conclude that body size at birth affects stature at puberty; in girls, smallness for gestational age is associated with earlier puberty. Associations between intrauterine exposures and disease risk may be confounded by, or mediated through, effects on adolescence.     

Delta-opioid receptor immunoreactivity on astrocytes is upregulated during mitosis

Endogenous opioid peptides and opioid receptors are expressed by brain cells early during normal development, and exogenous opiate exposure in this period is known to affect brain cell proliferation and maturation. Despite the abundant evidence that opioids affect brain development, little is known about the mechanisms involved. In this study cortical astrocytes in primary culture were examined immunohistochemically by using antibodies against the opioid receptors. The immunoreactivity for delta-opioid receptors was strongly upregulated during mitosis with an increase in immunostaining that started in early prophase and lasted through the M-phase to cytokinesis. Similar effects could not be observed when antibodies against the mu- or kappa-opioid receptor subtypes were used. Cultured neurons and microglia presented a strong and homogenous immunostaining for the delta-opioid receptor and no further upregulation of immunoreactivity could be detected in these cells. The presence of functional delta-opioid receptors on the mitotic astrocytes was verified by using microspectrofluorometry for detection of delta-opioid agonist induced changes in intracellular free calcium concentrations ([Ca2+]i). In these experiments fluo-3/AM incubated cells showed a rapidly induced delta-opioid agonist (DPDPE, 10(-6) M) evoked increase in [Ca2+]i. These results suggest an upregulation of the delta-opioid receptors that could represent a mechanism involved in the response to opioids in the developing brain.     

Interaction between voluntary and postural motor commands during perturbed lifting

STUDY DESIGN: An experimental study was conducted to evaluate the effect of an unexpected postural perturbation during a lifting task. OBJECTIVES: To investigate electromyographic responses in the erector spinae to a postural perturbation, simulating slipping, during an ongoing voluntary lifting movement. It was hypothesized that specific combinations of voluntary movement and postural perturbation present a situation in which injury caused by a rapid switch between conflicting motor commands can occur. SUMMARY OF BACKGROUND DATA: Studies of postural perturbations have mainly focused on behavior during static tasks such as quiet, upright standing. To date, there are no published studies of the effect of a perturbation during an ongoing voluntary lifting movement. METHODS: Subjects standing on a movable platform were exposed to random perturbations while lifting a 20-kg load. Muscle activity was recorded from flexor and extensor muscles of the trunk and hip. Trunk flexion angle in the sagittal plane was recorded with a video system. RESULTS: Perturbations forward were followed by an increased activity in erector spinae superimposed on the background activation present during the lift, indicating that both the voluntary and postural motor programs caused an activation of erector spinae. During backward perturbation, however, there was a sudden cessation of erector spinae activity followed by an extended period of rapid electromyographic amplitude fluctuations while the trunk was flexing, indicating an eccentric contraction of the erector spinae. CONCLUSIONS: This erratic behavior with large electromyographic amplitude fluctuations in the erector spinae after a backward slip during lifting may indicate a rapid switch between voluntary and postural motor programs that require conflicting functions of the back muscles. This may cause rapid force changes in load-carrying tissue, particularly in those surrounding the spine, thus increasing the risk of slip-and-fall-related back injuries.     

Developmentally Regulated Expression of HDNF/NT-3 mRNA in Rat Spinal Cord Motoneurons and Expression of BDNF mRNA in Embryonic Dorsal Root Ganglion

Northern blot analysis was used to demonstrate high levels of hippocampus-derived neurotrophic factor/neurotrophin-3 (HDNF/NT-3) mRNA in the embryonic day (E) 13 - 14 and 15 - 16 spinal cord. The level decreased at E18 - 19 and remained the same until postnatal day (P) 1, after which it decreased further to a level below the detection limit in the adult. In situ hybridization revealed that the NT-3 mRNA detected in the developing spinal cord was derived from motoneurons and the decrease seen at E18 - 19 was caused by a reduction in the number of motoneurons expressing NT-3 mRNA. The distribution of NT-3 mRNA-expressing cells in the E15 spinal cord was very similar to the distribution of cells expressing choline acetyltransferase or nerve growth factor receptor (NGFR) mRNA. Moreover, a striking similarity between the developmentally regulated expression of NT-3 and NGFR mRNA was noted in spinal cord motoneurons. A subpopulation of all neurons in the dorsal root ganglia expressed brain-derived neurotrophic factor (BDNF) mRNA from E13, the earliest time examined, to adulthood. These results are consistent with a trophic role of NT-3 for proprioceptive sensory neurons innervating the ventral horn, and imply a local action of BDNF for developing sensory neurons within the dorsal root ganglia.     

On the mechanism of kidney stone disintegration by acoustic shock waves

In the present study we have, by theoretical and experimental investigations, especially concentrated on the importance of acoustic streaming, transient cavitation and microstreaming in the fluid close to the stone. Artificial stones, round stones 20 mm in diameter made of Plaster of Paris or rectangular flat stones, 25 x 25 x 15 mm, were suspended in a water bath at the focus of an EDAP LT01 lithotripter. "Unprotected" stones were disintegrated while stones surrounded by a layer of silicone showed no or very small disintegration. For successful destruction of the calculus, it seems to be essential that the stones are surrounded by a liquid, i.e., water.     

Interaction between mothers and infants born at risk during the first six months of corrected age

Abstract The effects of preterm birth and the perinatal infant health condition on mother-infant interactions were analysed in 278 mother-infant pairs, divided into four groups according to infants' gestational age at birth: group 1. 23–31 weeks; group 2,32–36 weeks; group 3, 37–42 weeks; and group 4, a control group of healthy full-term infants. The methodological approach was based on observation of the pairs at 2,4 and 6 months of infants" corrected age (± 1 week) during undressing of the infant and face-to-face interaction. It was found that mother-infant pairs with preterm infants (groups 1 and 2) did not differ in interactional variables from those of the control group. On the other hand, the birth of a full-term infant in need of neonatal intensive care (group 3) affected maternal and infant interactive behaviour. Additionally, infants from group 3 did not show stability in their interactive behaviour between any ages of measurement. This result suggests that interactive behaviour of full-term infants in need of neonatal intensive care are rather unpredictable during their first 6 months of life, which might have contributed to the less optimal interactive pattern observed for their mothers compared with mothers of the control group.     

Wound ventilation with ultraclean air for prevention of direct airborne contamination during surgery.

BACKGROUND AND OBJECTIVE: Despite the novelties in operating room ventilation, airborne bacteria remain an important source of surgical wound contamination. An ultraclean airflow from the ceiling downward may convey airborne particles from the surgical team into the wound, thus increasing the risk of infection. Therefore, similar ventilation from the wound upward should be considered. We investigated the effect of wound ventilation on the concentration of airborne particles in a wound model during simulated surgery. DESIGN: Randomized experimental study simulating surgery with a wound cavity model. SETTING: An operating room of a university hospital ventilated with ultraclean air directed downward. INTERVENTIONS: Particles 5 microm and larger were counted with and without a 5-cm deep cavity and with and without the insufflation of ultraclean air. RESULTS: With the surgeon standing upright, no airborne particles could be detected in the wound model. In contrast, during simulated operations, the median number of particles per 0.1 cu ft reached 18 (25th and 75th percentiles, 12 and 22.25) in the model with a cavity and 15.5 (25th and 75th percentiles, 14 and 21.5) without. With a cavity, wound ventilation markedly reduced the median number of particles to 1 (range, 0 to 1.25; P < .001). CONCLUSIONS: To protect a surgical wound against direct airborne contamination, air should be directed away from the wound rather than toward it. This study provides supportive evidence to earlier studies that operating room ventilation with ultraclean air is imperfect during surgical activity and that wound ventilation may be a simple complement. Further clinical trials are needed.