Effects of exclusive breastfeeding for four versus six months on maternal nutritional status and infant motor development: results of two randomized trials in Honduras.
(49/2062)
To examine whether the duration of exclusive breastfeeding affects maternal nutrition or infant motor development, we examined data from two studies in Honduras: the first with 141 infants of low-income primiparous women and the second with 119 term, low birth weight infants. In both studies, infants were exclusively breastfed for 4 mo and then randomly assigned to continue exclusive breastfeeding (EBF) until 6 mo or to receive high-quality, hygienic solid foods (SF) in addition to breast milk between 4 and 6 mo. Maternal weight loss between 4 and 6 mo was significantly greater in the exclusive breastfeeding group (EBF) group than in the group(s) given solid foods (SF) in study 1 (-0.7 +/- 1.5 versus -0.1 +/- 1.7 kg, P < 0.05) but not in study 2. The estimated average additional nutritional burden of continuing to exclusively breastfeed until 6 mo was small, representing only 0.1-6.0% of the recommended dietary allowance for energy, vitamin A, calcium and iron. Women in the EBF group were more likely to be amenorrheic at 6 mo than women in the SF group, which conserves nutrients such as iron. In both studies, few women (10-11%) were thin (body mass index <19 kg/m(2)), so the additional weight loss in the EBF group in study 1 was unlikely to have been detrimental. Infants in the EBF group crawled sooner (both studies) and were more likely to be walking by 12 mo (study 1) than infants in the SF group. Taken together with our previous findings, these results indicate that the advantages of exclusive breastfeeding during this interval appear to outweigh any potential disadvantages in this setting. (+info)
Fetal growth, early postnatal growth and motor development in Pakistani infants.
(50/2062)
BACKGROUND: Studies have often compared the postnatal motor development of 'small' versus 'normal' newborns. Not much is known about the associations between a broad spectrum of size at birth and motor development. The effect of early postnatal growth on motor development is little researched. Growth failure in terms of shortness and thinness should be differentiated, but not many studies have the data for this analysis. METHODS: This is a longitudinal study of infants born in Lahore, Pakistan, between 1984 and 1987. Age at commencement of independent walking and age at 'building a 3-cube tower' were taken as indicators of gross and fine motor development, respectively. Size at birth was captured by length and thinness as continuous variables; postnatal growth from birth to 6 months of age was measured by changes in length and thinness. Adjustment for covariates and handling of censored cases were performed by generalized log gamma regression. RESULTS: Thinness at birth and postnatal stunting and wasting had a linear, inverse association with gross motor development (each P < 0.05). Birth length had a non-linear, inverse association with this outcome (P < 0.05). Birth length, thinness at birth and postnatal wasting had a linear, inverse association with fine motor development (each P < 0.05). CONCLUSION: Both fetal and early postnatal growth over a broad spectrum may affect infants' motor development. It is not just the babies who were very small at birth that suffered. Birth length appeared to be more influential than other anthropometric indicators. (+info)
Improving continuing medical education for surgical techniques: applying the lessons learned in the first decade of minimal access surgery.
(51/2062)
OBJECTIVE: To examine the first decade of experience with minimal access surgery, with particular attention to issues of training surgeons already in practice, and to provide a set of recommendations to improve technical training for surgeons in practice. SUMMARY BACKGROUND DATA: Concerns about the adequacy of training in new techniques for practicing surgeons began almost immediately after the introduction of laparoscopic cholecystectomy. The concern was restated throughout the following decade with seemingly little progress in addressing it. METHODS: A preliminary search of the medical literature revealed no systematic review of continuing medical education for technical skills. The search was broadened to include educational, medical, and psychological databases in four general areas: surgical training curricula, continuing medical education, learning curve, and general motor skills theory. RESULTS: The introduction and the evolution of minimal access surgery have helped to focus attention on technical skills training. The experience in the first decade has provided evidence that surgical skills training shares many characteristics with general motor skills training, thus suggesting several ways of improving continuing medical education in technical skills. CONCLUSIONS: The educational effectiveness of the short-course type of continuing medical education currently offered for training in new surgical techniques should be established, or this type of training should be abandoned. At present, short courses offer a means of introducing technical innovation, and so recommendations for improving the educational effectiveness of the short-course format are offered. These recommendations are followed by suggestions for research. (+info)
Animal models of alcohol withdrawal.
(52/2062)
One diagnostic criterion of alcohol dependence is the appearance of a withdrawal syndrome when alcohol consumption ceases. Researchers have used various animal models, including isolated brain cells, slices of brain tissue, and intact animals, to study the mechanisms and manifestations of withdrawal. Results from these experimental studies have demonstrated that many consequences of withdrawal found in animals resemble those observed in humans. Such signs and symptoms of alcohol withdrawal include enhanced activity of the autonomic nervous system; body posture and motor abnormalities; hyperexcitability of the central nervous system, including sensory hyperreactivity; convulsions; anxiety; and psychological discomfort. Researchers also have used animal models to study the electrophysiological correlates of withdrawal, as well as neurobiological mechanisms underlying alcohol dependence and withdrawal. (+info)
Growth, development, and behavior in early childhood following prenatal cocaine exposure: a systematic review.
(53/2062)
CONTEXT: Despite recent studies that failed to show catastrophic effects of prenatal cocaine exposure, popular attitudes and public policies still reflect the belief that cocaine is a uniquely dangerous teratogen. OBJECTIVE: To critically review outcomes in early childhood after prenatal cocaine exposure in 5 domains: physical growth; cognition; language skills; motor skills; and behavior, attention, affect, and neurophysiology. DATA SOURCES: Search of MEDLINE and Psychological Abstracts from 1984 to October 2000. STUDY SELECTION: Studies selected for detailed review (1) were published in a peer-reviewed English-language journal; (2) included a comparison group; (3) recruited samples prospectively in the perinatal period; (4) used masked assessment; and (5) did not include a substantial proportion of subjects exposed in utero to opiates, amphetamines, phencyclidine, or maternal human immunodeficiency virus infection. DATA EXTRACTION: Thirty-six of 74 articles met criteria and were reviewed by 3 authors. Disagreements were resolved by consensus. DATA SYNTHESIS: After controlling for confounders, there was no consistent negative association between prenatal cocaine exposure and physical growth, developmental test scores, or receptive or expressive language. Less optimal motor scores have been found up to age 7 months but not thereafter, and may reflect heavy tobacco exposure. No independent cocaine effects have been shown on standardized parent and teacher reports of child behavior scored by accepted criteria. Experimental paradigms and novel statistical manipulations of standard instruments suggest an association between prenatal cocaine exposure and decreased attentiveness and emotional expressivity, as well as differences on neurophysiologic and attentional/affective findings. CONCLUSIONS: Among children aged 6 years or younger, there is no convincing evidence that prenatal cocaine exposure is associated with developmental toxic effects that are different in severity, scope, or kind from the sequelae of multiple other risk factors. Many findings once thought to be specific effects of in utero cocaine exposure are correlated with other factors, including prenatal exposure to tobacco, marijuana, or alcohol, and the quality of the child's environment. Further replication is required of preliminary neurologic findings. (+info)
A novel member of the Ig superfamily, turtle, is a CNS-specific protein required for coordinated motor control.
(54/2062)
We describe here the cloning and functional characterization of a neural-specific novel member of the Ig superfamily, turtle (tutl), with a structure of five Ig C2-type domains, two fibronectin type III domains, and one transmembrane region. Alternative splicing of the tutl gene produces at least four Tutl isoforms, including two transmembrane proteins and two secreted proteins, with primary structures closely related to a human brain protein (KIAA1355), the Deleted in Colorectal Cancer/Neogenin/Frazzled receptor family, and the Roundabout/Dutt1 receptor family. An allelic series of tutl gene mutations resulted in recessive lethality to semilethality, indicating that the gene is essential. In contrast to other family members, tutl does not play a detectable role in axon pathfinding or nervous system morphogenesis. Likewise, basal synaptic transmission and locomotory movement are unaffected. However, tutl mutations cause striking movement defects exhibited in specific types of highly coordinated behavior. Specifically, tutl mutants display an abnormal response to tactile stimulation, the inability to regain an upright position from an inverted position (hence, "turtle"), and the inability to fly in adulthood. These phenotypes demonstrate that tutl plays an essential role in establishing a nervous system capable of executing coordinated motor output in complex behaviors. (+info)
Sensorimotor and physiological effects of various alcoholic beverages.
(55/2062)
Effects of a standard dose of alcohol (1.3 g/kg) in the form of Canadian rye whisky, Canadian beer and a sparkling table wine were compared with those of a nonalcoholic carbonated control beverage. Sixteen young male and eight female subjects, all moderate drinkers, were tested in a Latin square design. Measurements were made on the pursuit rotor and quantitative Romberg tests, and of skin temperature, heart rate, malar flush and blood alcohol concentration during the prealcohol baseline period and at regular intervals over the 4-hour drinking period. The three alcoholic beverages produced blood alcohol curves that did not differ significantly. All three alcoholic beverages produced increasing sensorimotor impairment over time, which corresponded in degree to the increasing blood alcohol concentration. There were no significant differences between the three beverages on either the sensorimotor or physiological measures at any blood alcohol value. The results of this study indicate that the degree of impairment after alcohol ingestion in a socially relevant manner is not dependent on the type of beverage consumed, but only on the resulting blood alcohol concentration. (+info)
Modulation of practice-dependent plasticity in human motor cortex.
(56/2062)
Motor practice may lead to expansion of trained representations in the motor cortex, but it is unknown whether this practice-dependent plasticity can be purposefully enhanced or depressed. Evidence, mainly based on animal experiments, indicates that the activity of GABA-related cortical inhibition is important in controlling the extent to which plasticity may occur. We tested the role of GABA in modulating practice-dependent plasticity in the human motor cortex. A decrease in GABA-related cortical inhibition was achieved by ischaemic nerve block (INB) in the hand by deafferentation/deefferentation and an increase was achieved by administration of the GABA(A) receptor agonist lorazepam. In Experiment 1, healthy subjects performed motor practice (MP), consisting of repeated ballistic contractions of the biceps muscle in the absence (MP alone) or presence of INB (MP+INB). Changes in the biceps motor cortex representation were assessed by transcranial magnetic stimulation (TMS). MP+INB resulted in a dramatic increase in the size of the motor evoked potential (MEP) and in paired-pulse excitability compared with mild or no changes in the MP-alone and INB-alone conditions. In Experiment 2, this dramatic increase in biceps representation induced by MP+INB was replicated when subjects were pretreated with placebo, but this increase was prevented or even switched to a decrease when subjects were pretreated with lorazepam. These findings indicate that a decrease in GABA-related inhibition facilitates practice-dependent plasticity in the human motor cortex, whereas an increase depresses it. In Experiment 3, practice-dependent plasticity (assessed by TMS, as in the first two experiments) was also tested at the behavioural level. The dramatic increase in biceps MEP size induced by MP+INB was paralleled by an increase in peak acceleration of the fastest elbow flexion movements. Similarly, the lack of change in MEP size in the MP-alone condition was paralleled by a lack of change in peak acceleration. We propose that changes in GABA activity may be instrumented to modulate plasticity purposefully; for instance, to enhance plastic change and recovery of function after a lesion in neurological patients. (+info)