Predicting soil respiration from peatlands.

This study considers the relative performance of six different models to predict soil respiration from upland peat. Predicting soil respiration is important for global carbon budgets and gap filling measured data from eddy covariance and closed chamber measurements. Further to models previously published new models are presented using two sub-soil zones and season. Models are tested using data from the Bleaklow plateau, southern Pennines, UK. Presented literature models include ANOVA using logged environmental data, the Arrhenius equation, modified versions of the Arrhenius equation to include soil respiration activation energy and water table depth. New models are proposed including the introduction of two soil zones in the peat profile, and season. The first new model proposes a zone of high CO(2) productivity related to increased soil microbial CO(2) production due to the supply of labile carbon from plant root exudates and root respiration. The second zone is a deeper zone where CO(2) production is lower with less labile carbon. A final model allows the zone of high CO(2) production to become dormant during winter months when plants will senesce and will vary depending upon vegetation type within a fixed location. The final model accounted for, on average, 31.9% of variance in net ecosystem respiration within 11 different restoration sites whilst, using the same data set, the best fitting literature equation only accounted for 18.7% of the total variance. Our results demonstrate that soil respiration models can be improved by explicitly accounting for seasonality and the vertically stratified nature of soil processes. These improved models provide an enhanced basis for calculating the peatland carbon budgets which are essential in understanding the role of peatlands in the global C cycle.

A two-year-old boy with language regression and unusual social interactions.

CASE: Jimmy, a 2 1/2-year-old boy, was seen for the first time by a new pediatrician after a recent family move. His mother made the appointment for a health supervision visit although she had concerns about his language and social skills. She stated that he spoke primarily with unintelligible sounds and often communicated by pointing with his finger. He spoke only 10 words that were clear enough to be understood. Jimmy's mother said that he could hear, but she was not sure whether he understood everything she said. Although he played at home with his 4-year-old brother, he typically played by himself when he was in the presence of other children. Jimmy's mother was asked if he had had a 2-year-old visit to a pediatrician and what the assessment was at that time. She said that his delayed development was discussed with the pediatrician, but she was reassured that he would progress during the following year. An uncomplicated full-term gestation was followed by a vaginal delivery without perinatal problems. Jimmy was a "calm" baby who was breastfed for the first 6 months of life. He sat at 7 months, pulled himself up to stand with support at approximately 9 months, and walked at 13 months. Transitions were always difficult for Jimmy; he screamed and was difficult to settle whenever cared for by someone other than his parents. He typically resists physical contact when children or adults approach him. His mother recalled that language emerged early. He acquired a significant number of words between 12 and 15 months of age. Jimmy apparently recognized letters when his parents were teaching the older sibling. At 15 months, Jimmy's language output regressed dramatically, and by 18 months, he no longer used words to communicate. Since then, he has spoken fewer than 10 single words. He mostly babbles and uses repetitions of the same sounds. The pediatrician inquired into family structure and life events at the time Jimmy lost language milestones. He was told that, at this time, the father, an engineer, changed his position in the company and began to travel extensively. Jimmy's mother thought that the absence of his father might be related to the language regression. She also noted that Jimmy seemed to have a stronger attachment for his father: "Jimmy has always been attracted to his father, and his brother seems to prefer me." The parents' marriage was strong and free of any major disharmony. During the interview, the pediatrician noted that Jimmy played persistently with his set of small trains, repetitiously lining them up in order. He was not interested in other toys that were on the floor next to him. He ran around the trains, mostly on his toes, while making unintelligible sounds. He looked away when the pediatrician called his name and became agitated when his mother attempted to redirect his attention to the examination. The pediatrician, 4 years in practice after his residency, had never seen a child with Jimmy's pattern of development. That Jimmy's development was unusual in two domains was apparent to his pediatrician from the preceding information and brief observations. He asked himself what the next steps should be.

Osteopenia in Rett syndrome.

Bone density analysis, dietary intake, and anthropometrics were compared in 20 subjects with Rett syndrome (RS), 25 normal control subjects, and 11 girls with cerebral palsy. Bone mineral density, bone mineral content, and spine (bone) mineral density were significantly reduced in the RS group. When weight and age were kept constant, the bone density was still reduced in the patients with RS. Subjects with RS are at risk for osteoporosis.

Prenatal cocaine exposure and fetal vascular disruption.

The question of the potential teratogenicity of cocaine has been raised by the increasing frequency of its abuse in the United States. In previous studies, an increased incidence has been documented of spontaneous abortion, placental abruption, prematurity, intrauterine growth retardation, and neurologic deficits in the infants of women who abused cocaine. More recently, it has been suggested in studies that fetal vascular disruption accompanying maternal cocaine abuse may lead to cavitary central nervous system lesions and genitourinary anomalies. In this article, 10 children born of women who abused cocaine are described, 9 of whom have congenital limb reduction defects and/or intestinal atresia or infarction. The spectrum of anomalies associated with embryonic and fetal vascular disruption accompanying maternal cocaine abuse is thus enlarged. The specific risk for congenital anomalies accompanying maternal cocaine abuse during an individual pregnancy is unknown. However, data from these patients and the available literature suggest that counseling pregnant women concerning cocaine use should incorporate warnings about the possibility of associated embryonic or fetal vascular disruption.

Echoencephalographic findings in neonates associated with maternal cocaine and methamphetamine use: incidence and clinical correlates.

Term neonates (n = 74) exposed antenatally to cocaine, methamphetamine, or cocaine and a narcotic but without any other known perinatal complications were prospectively examined with cranial ultrasonography to detect the presence of central nervous system injury. These studies were compared with those of a drug-free but clinically ill group of infants (n = 87) at risk for hypoxicischemic encephalopathy, and with those of infants who were well. Cranial abnormalities were detected by ultrasonography in 35.1% of the drug-exposed infants, similar to the incidence in the infants at risk for hypoxic-ischemic injury (p = 0.7) but significantly greater than the 5.3% incidence of abnormalities in normal infants (p less than 0.001). The lesions in the drug-exposed infants were intraventricular hemorrhage, echodensities known to be associated with necrosis, and cavitary lesions; they were focused in the basal ganglion, frontal lobes, and posterior fossa. The presence of ultrasonographic abnormalities was not predicted by standard neonatal clinical assessment or by other perinatal risk factors present in the drug-using population. The types of cerebral injury are consistent with those seen in adult cocaine and methamphetamine abusers and are probably related to the vasoconstrictive properties of these drugs. Antenatal exposure to stimulant drugs is associated with significant risk for cerebral injury, even among seemingly normal term neonates.

Cocaine exposure in a term neonate. Necrotizing enterocolitis as a complication.

Cocaine use has increased dramatically in the past several years, and multiple medical complications associated with its use have been reported in adults, including bowel infarction and colitis. Maternal use of cocaine during pregnancy has been associated with complications in the fetus and newborn infant, including spontaneous abortions, preterm labor, cerebral infarctions, seizures, renal anomalies, and neurobehavioral and neurophysiologic abnormalities. This paper presents a case of necrotizing enterocolitis at birth in a term newborn exposed to cocaine antenatally. Cultures of the bowel grew two types of Clostridia organisms, Escherichia coli and group B streptococcus. It is suggested that bowel ischemia was secondary to the vasoconstrictive properties of the maternally abused cocaine and that secondary invasion of the bowel by multiple bacteria ensued. This case presents another possible complication to the newborn of maternal cocaine exposure in utero, namely ischemic infarction of the bowel.

Waterbed care of narcotic-exposed neonates. A useful adjunct to supportive care.

We describe the neonatal course of 30 antenatal narcotic-exposed newborns, half of whom were randomly assigned to nonoscillating waterbeds and half to conventional bassinets. The infants were comparable at birth regarding drug exposure, ethnicity, maternal medical factors, gestational age, growth, and severity of withdrawal at the time of onset. Evaluation of total and subscores of the abstinence syndrome showed a lower total score and a significantly lower central nervous system subscore on day 5 for infants on waterbeds. The infants on waterbeds required less medication to control symptoms. The waterbed group demonstrated a significantly earlier onset of consistent weight gain as compared with the control group. This study demonstrates that nonoscillating waterbeds are an inexpensive and effective component of supportive therapy in the care of narcotic-exposed neonates.

Perinatal cocaine and methamphetamine exposure: maternal and neonatal correlates.

Maternal and neonatal growth, behavior, and physiologic organization were evaluated in 104 mother-infant pairs with positive results of urine toxicology screens. ANOVA comparison of cocaine, methamphetamine, and cocaine plus methamphetamine groups revealed no significant differences in perinatal variables. The Finnegan withdrawal scoring scheme demonstrated that all three groups of infants had altered neonatal behavioral patterns, characterized by abnormal sleep patterns, poor feeding, tremors, and hypertonia. Infants exposed to cocaine or methamphetamine or both were combined and compared with both narcotic-exposed and drug-free mother-infant pairs matched for known maternal risk factors. All drug-exposed groups had significantly higher rates of prematurity and intrauterine growth retardation and smaller head circumferences than did the drug-free comparison group. A significantly higher rate of placental hemorrhage occurred in the cocaine plus methamphetamine group. Stepwise multiple regression analysis assessed the independent contribution of maternal factors; cocaine or methamphetamine was adversely, negatively associated with gestational age, birth weight, length, and occipitofrontal circumference. The increased rate of prematurity, intrauterine growth retardation, and perinatal complications associated with perinatal exposure to cocaine or methamphetamine was greater than that predicted by coexisting risk factors and was consistent with the pharmacologic properties of these drugs.

The development of gait: a study in African children ages one to five.

The purpose of this study was to describe quantitatively the gait development of a group of African children to determine how the pattern changes would relate to growth and maturation. This work applies an established technology of gait analysis to field conditions. 65 children of the Gusii tribe from southwestern Kenya were selected for study with an age range from 13 months to 69 months. Gait evaluation was performed by film recording free-cadence walking of the children. Growth in stature and age both influence the gait patterns. Developmental patterns of alteration in velocity, stride length, and cadence quantitatively measured in this study closely parallel observations made on children in laboratory settings by other workers.

Regional anesthesia during newborn circumcision. Effect on infant pain response.

A controlled, double-blind investigation was undertaken to determine whether regional anesthesia by dorsal penile nerve block (DPNB) could effectively minimize the pain and behavioral disruptions usually associated with newborn circumcision. Fifteen infants had DPNB with lidocaine, eight control infants had DPNB with saline, and eight additional control infants were circumcised without undergoing DPNB. Newborn distress was gauged by subjective observation, measurement of heart rate, and the percent of time spent crying in six sequential timed intervals during circumcision. Ninety-three percent of subjects who received lidocaine were observed to have a decrease in agitation after anesthetic administration. The mean increase in heart rate during circumcision was at least 50 percent less in the lidocaine injected group than in either control group (p less than 0.01). Infants who had DPNB with lidocaine cried 50 percent less during circumcision compared to combined controls (p less than 0.01). DPNB was easily administered, and there were no significant complications. Physicians who circumcise newborns have good reason to employ the technique of dorsal penile nerve block with lidocaine to minimize infant pain and distress.

Malnutrition: a closer look at the problem in an East African village.

Assessments were made of 20 severely malnourished children under three years of age in a relatively prosperous village in East Africa. These included medical, perinatal, social, economic and behavioural/developmental histories, as well as physical and developmental evaluations. The findings are presented in relation to data from a longitudinal study of child development from this same site and from large nutrition surveys of the same area. The specific historical factors and behavioural profiles found to occur with high frequency among the malnourished children are discussed. They suggest a common etiology with other disorders of attachment--child abuse, nonorganic failure to thrive, and the 'vulnerable child' syndrome. These commonalities are explored, and possible mechanisms in the emergence of bonding failure are considered.