Signaling via the transcriptionally regulated activin receptor 2B is a novel mediator of neuronal cell death during chicken ciliary ganglion development.

The TGF-ß ligand superfamily members activin A and BMP control important aspects of embryonic neuronal development and differentiation. Both are known to bind to activin receptor subtypes IIA (ActRIIA) and IIB, while in the avian ciliary ganglion (CG), so far only ActRIIA-expression has been described. We show that the expression of ACVR2B, coding for the ActRIIB, is tightly regulated during CG development and the knockdown of ACVR2B expression leads to a deregulation in the execution of neuronal apoptosis and therefore affects ontogenetic programmed cell death in vivo. While the differentiation of choroid neurons was impeded in the knockdown, pointing toward a reduction in activin A-mediated neural differentiation signaling, naturally occurring neuronal cell death in the CG was not prevented by follistatin treatment. Systemic injections of the BMP antagonist noggin, on the other hand, reduced the number of apoptotic neurons to a similar extent as ACVR2B knockdown. We therefore propose a novel pathway in the regulation of CG neuron ontogenetic programmed cell death, which could be mediated by BMP and signals via the ActRIIB.

Salivary cortisol as a predictor of socioemotional adjustment during kindergarten: a prospective study.

This study, based on a sample of 172 children, examined the relation between average afternoon salivary cortisol levels measured at home at age 4.5 years and socioemotional adjustment a year and a half later, as reported by mothers, fathers, and teachers. Cortisol levels were hypothesized to be positively associated with withdrawal-type behaviors (e.g., internalizing, social wariness) and inversely related to approach-type behaviors, both negative and positive (e.g., externalizing, school engagement). Higher cortisol levels at age 4.5 predicted more internalizing behavior and social wariness as reported by teachers and mothers, although child gender moderated the relation between cortisol and mother report measures. An inverse relation was found between boys' cortisol levels and father report of externalizing behavior. A marginal inverse relation was found between child cortisol levels and teacher report of school engagement. Behavior assessed concurrently with cortisol collection did not account for the prospective relations observed,suggesting that cortisol adds uniquely to an understanding of behavioral development.

Properties and interaction of heterologously expressed glutamate decarboxylase isoenzymes GAD(65kDa) and GAD(67kDa) from human brain with ginkgotoxin and its 5'-phosphate.

Two isoforms of glutamate decarboxylase (GAD(65kDa) and GAD(67kDa)) from human brain, which had previously been overexpressed in Escherichia coli as fusion proteins containing a glutathione-S-transferase domain, were purified by affinity chromatography on glutathione Sepharose 4B. Both isoforms were also expressed in Saccharomyces cerevisiae. After modification of a HPLC based assay, the enzymes were characterized with respect to their biochemical properties. Comparison of kinetic data, pH, and temperature optima as well as of the mode of interaction with pyridoxal phosphate as a cofactor revealed several significant differences between the two isoenzymes reflecting their somewhat different physiological and molecular features. Investigation of the influence of 4'-O-methylpyridoxine (ginkgotoxin) (1), a neurotoxin occurring in Ginkgo biloba L., on the different isoenzymes, indicates that the phosphorylated form of the toxin, 4'-O-methylpyridoxine-5'-phosphate (2), decreases GAD(65kDa) activity, although in unphysiologically high concentrations, whereas GAD(67kDa) activity seems to be hardly affected.

Urkinase: structure of acetate kinase, a member of the ASKHA superfamily of phosphotransferases.

Acetate kinase, an enzyme widely distributed in the Bacteria and Archaea domains, catalyzes the phosphorylation of acetate. We have determined the three-dimensional structure of Methanosarcina thermophila acetate kinase bound to ADP through crystallography. As we previously predicted, acetate kinase contains a core fold that is topologically identical to that of the ADP-binding domains of glycerol kinase, hexokinase, the 70-kDa heat shock cognate (Hsc70), and actin. Numerous charged active-site residues are conserved within acetate kinases, but few are conserved within the phosphotransferase superfamily. The identity of the points of insertion of polypeptide segments into the core fold of the superfamily members indicates that the insertions existed in the common ancestor of the phosphotransferases. Another remarkable shared feature is the unusual, epsilon conformation of the residue that directly precedes a conserved glycine residue (Gly-331 in acetate kinase) that binds the alpha-phosphate of ADP. Structural, biochemical, and geochemical considerations indicate that an acetate kinase may be the ancestral enzyme of the ASKHA (acetate and sugar kinases/Hsc70/actin) superfamily of phosphotransferases.

Clustering of isochorismate synthase genes menF and entC and channeling of isochorismate in Escherichia coli.

There are two isochorismate synthase genes entC and menF in Escherichia coli. They encode enzymes (isochorismate synthase, EC 5.4.99.6) which reversibly synthesize isochorismic acid from chorismic acid. The genes share a 24.2% identity but are differently regulated. Activity of the MenF isochorismate synthase is significantly increased under anaerobic conditions whereas the activity of the EntC isochorismate synthase is greatly stimulated during growth in an iron deficient medium. Isochorismic acid synthesized by EntC is mainly channeled into enterobactin synthesis whereas isochorismic acid synthesized by MenF is mainly channeled into menaquinone synthesis. When menF or entC were separately placed onto overexpression plasmids and the plasmids introduced into a menF(-)/entC(-) double mutant in two separate experiments, the isochorismate formed was fed into both, the menaquinone and the enterobactin pathway. Moreover, in spite of a high isochorismate synthase activity menaquinone and enterobactin formation were not fully restored, indicating that isochorismate was lost by diffusion. Thus, under these conditions channeling was not observed. We conclude that in E. coli the chromosomal position of both menF and entC in their respective clusters is a prerequisite for channeling of isochorismate in both pathways.

Genetic analyses of focal aspects of infant temperament.

The authors explored the genetic and environmental underpinnings of individual differences in temperament with a sample of 604 3- to 16-month-old infant twins and their parents. Mothers completed Rothbart's Infant Behavior Questionnaire (IBQ), and a subsample of 140 9-month-old twins participated in behavioral assessment of temperament in the laboratory as well. For IBQ Smiling and Laughter and Duration of Orienting, both additive genetic and shared environmental effects were needed to best represent the data. Shared environmental effects fully accounted for cotwin similarity for IBQ Soothability, and conversely, additive genetic effects fully accounted for cotwin similarity for the IBQ Distress to Limitations, Distress to Novelty, and Activity Level scales. With the subsample, the authors fit a multivariate model to mother report, father report, and lab measures of stranger distress and found that genetic influences were most important for the covariation among these measures.

Fear and anger regulation in infancy: effects on the temporal dynamics of affective expression.

Emotion regulation has been conceptualized as the extrinsic and intrinsic processes responsible for monitoring, facilitating, and inhibiting heightened levels of positive and negative affect. Regulation of distress is related to the use of certain behavioral strategies. Our study examined whether putative regulatory behaviors widely assumed to be conceptually associated with these strategies are actually empirically associated with the changes in fearful and angry distress in 6-, 12-, and 18-month-old infants. Our key finding was that the use of some putative regulatory behaviors (e.g., distraction and approach) reduced the observable intensity of anger but were less effective in reducing the intensity of fear. The results suggest (1) caution in assuming that postulated regulatory behaviors actually have general distress-reducing effects and (2) the likelihood that "distress" is too global a construct for research on emotion regulation.

Toddler and childhood temperament: expanded content, stronger genetic evidence, new evidence for the importance of environment.

Using samples of twins and singletons totaling 715 individuals, the authors document heritable influences on various temperamental dimensions during the toddler and preschooler age ranges, which have been somewhat understudied relative to infants and older adolescents. In contrast to instruments on which prior literature is based, the Toddler Behavior Assessment Questionnaire and the Children's Behavior Questionnaire offer assessment of positive affectivity (separately from negative affectivity) and of emotional regulation. Positive affect reveals substantial shared environmental influence, and emotion regulation reveals additive genetic influence. Evidence for genetic variance in temperament is strengthened because intraclass correlations from many of these questionnaire scales show no evidence of "too-low" dizygotic correlations that imply contrast effects. Suggestive evidence is offered that psychometric characteristics of the questionnaires can affect biometric inferences.

Crystallization of acetate kinase from Methanosarcina thermophila and prediction of its fold.

The unique biochemical properties of acetate kinase present a classic conundrum in the study of the mechanism of enzyme-catalyzed phosphoryl transfer. Large, single crystals of acetate kinase from Methanosarcina thermophila were grown from a solution of ammonium sulfate in the presence of ATP. The crystals diffract to beyond 1.7 A resolution. Analysis of X-ray data from the crystals is consistent with a space group of C2 and unit cell dimensions a = 181 A, b = 67 A, c = 83 A, beta = 103 degrees. Diffraction data have been collected from the crystals at 110 and 277 K. Data collected at 277 K extend to lower resolution, but are more reproducible. The orientation of a noncrystallographic two-fold axis of symmetry has been determined. Based on an analysis of the predicted amino acid sequences of acetate kinase from several organisms, we hypothesize that acetate kinase is a member of the sugar kinase/actin/hsp70 structural family.

Behavioral inhibition and stress reactivity: the moderating role of attachment security.

The role of the mother-toddler attachment relationship in moderating the relations between behavioral inhibition and changes in salivary cortisol levels in response to novel events was examined in 77 18-month-olds. Behavioral inhibition was determined by observing toddler inhibition of approach to several novel events. Attachment security to mother was assessed using the Ainsworth Strange Situation. Changes in salivary cortisol were used to index activity of the stress-sensitive hypothalamic-pituitary-adrenocortical (HPA) system. In addition, toddler coping behaviors and the behaviors used by mothers to help toddlers manage novel events were examined. Elevations in cortisol were found only for inhibited toddlers in insecure attachment relationships. Mothers in these relationships appeared to interfere with their toddlers' coping efforts. These results are discussed in the context of a coping model of the relations between temperament and stress reactivity.

Stress reactivity and attachment security.

Seventy-three 18-month-olds were tested in the Ainsworth Strange Situation. These children were a subset of 83 infants tested at 2, 4, 6, and 15 months during their well-baby examinations with inoculations. Salivary cortisol, behavioral distress, and maternal responsiveness measures obtained during these clinic visits were examined in relation to attachment classifications. In addition, parental report measures of the children's social fearfulness in the 2nd year of life were used to classify the children into high-fearful versus average- to low-fearful groups. In the 2nd year, the combination of high fearfulness and insecure versus secure attachment was associated with higher cortisol responses to both the clinic exam-inoculation situation and the Strange Situation. Thus, attachment security moderates the physiological consequences of fearful, inhibited temperament. Regarding the 2-, 4-, and 6-month data, later attachment security was related to greater maternal responsiveness and lower cortisol baselines. Neither cortisol nor behavioral reactivity to the inoculations predicted later attachment classifications. There was some suggestion, however, that at their 2-month checkup, infants who would later be classified as insecurely attached exhibited larger dissociations between the magnitude of their behavioral and hormonal response to the inoculations. Greater differences between internal (hormonal) and external (crying) responses were also negatively correlated with maternal responsiveness and positively correlated with pretest cortisol levels during these early months of life.

Ethnography, epidemiology and infertility in Egypt.

Infertility in the developing world has been relatively neglected as an international health problem and a topic of social scientific and epidemiological inquiry. In this study, we examine factors placing poor urban Egyptian men and women at risk of infertility, and we explore the sociocultural and political-economic contexts in which these health-demoting factors are perpetuated. Our approach to the problem of Egyptian infertility attempts an explicit merging of ethnographic and epidemiological research designs, methods of data collection and analysis, and interpretive insights to provide improved understanding of the factors underlying infertility in the urban Egyptian setting.

Infertility, infection, and iatrogenesis in Egypt: the anthropological epidemiology of blocked tubes.

In this article, we integrate medical anthropological and analytical epidemiological methods, forms of data analysis, and interpretive insights to examine the culture-specific behavioral factors that place poor, urban Egyptian women at risk of tubal-factor infertility (TFI). Such risk factors include biomedically and ethnomedically produced iatrogenesis, including the consequences of the practice of female circumcision, and male sexual behavior leading to sterilizing sexually transmitted diseases (STDs) in their female sexual partners. We examine the socio-cultural and political-economic context in which infertility-producing behavioral risk factors are maintained, and we explore the ways in which these risk factors are perceived by biomedically trained Egyptian gynecologists.

Infant resuscitation is associated with an increased risk of left-handedness.

The etiology of left lateral preference is not well understood, but some studies have suggested that it can be caused by complications at birth. The authors used data from the Child Health and Development Study, a large prospective study of pregnancy and child development conducted 1959-1966 in the San Francisco Bay Area of California, to examine the association between specific birth stressors and hand and foot preference. The study population consisted of 6,968 5-year-olds with no severe congenital abnormalities, and the authors controlled for potential demographic confounders and familial left-handedness. Infants who required resuscitation after delivery or who were twins or triplets were about twice as likely to demonstrate left hand preference at age 5 years (odds ratio (OR) = 1.8, 95% confidence interval (CI) 1.3-2.5, and OR = 2.2, 95% CI 1.2-4.0, respectively). Left-footedness was also significantly associated with the same stressors. No other individual stresses were significantly associated with left-lateral preference, and a composite measure indicated only a weak association. Although males, blacks, and those with left-handed siblings are more likely to show left lateral preference, these variables do not confound the association between birth stress and left lateral preference. These results indicate that specific types of birth stress are strongly associated with left hand and foot preference; however, much of the left laterality in non-clinical populations remains unexplained.

Decerebrate rigidity and vegetative signs in the acute midbrain syndrome with special regard to motor activity and intracranial pressure.

Decerebrate rigidity, intracranial pressure and vegetative signs were studied in 25 patients. Advanced statistical techniques were used to analyse the interrelationships between muscle activity (IEMG), blood pressure (ABP), intracranial pressure (ICP), pulse rate (HR), respiratory rate (RR), and central venous pressure (CVP) occurring during paroxysms of decerebration. The pattern of reaction is influenced by compression or stress imposed on the brain stem at the tentorial incisure and is related to the degree of cisternal obstruction. Significant differences in reaction were disclosed between provoked and spontaneous decerebration posturing.

Intracranial pressure and muscle activity in patients with decerebrate rigidity.

The authors analyse the relationship between the muscle activity during paroxysms of decerebration and the intracranial pressure. These relationships differ, and depend upon the presence or absence of mesencephalic herniation and patency of the perimesencephalic cisterns, as well as on whether the decerebration posturing has been spontaneous or induced by external stimulus. It is suggested that the magnitude of ICP reaction during decerebration is connected with the possibility of compensating the increased intracranial volume and with the strain imposed upon the brain stem at the mesencephalic level. Close correlations between the vegetative variables occuring during spontaneous DR paroxysms suggest a common excitatory neuronal mechanism. In cases when decerebration is provoked by external stimuli the response becomes more complex and not uniform.