Psychosocial Concerns and Health-Compromising Behaviors among Overweight and Nonoverweight Adolescents

Objective: To compare weight-specific and global psychosocial concerns and health-compromising behaviors among overweight and nonoverweight youth across gender and ethnicity. Methods: A cross-sectional school-based survey of 31,122 adolescents in grades 7 to 12. Based on self-reported heights and weights, respondents were categorized as nonoverweight (body mass index (BMI) <85th percentile), moderately overweight (85th percenile <BMI <95th percentile), or severely overweight (BMI >95th percentile). Results: Global psychosocial concerns, such as emotional well-being, suicidal ideation, future job concerns, and peer concerns, did not differ greatly between nonoverweight, moderately overweight, and severely overweight adolescents. Substance abuse behaviors were equally or less prevalent among the overweight group. Overweight girls were significantly less likely to consume alcohol, whereas overweight boys were at lower risk for marijuana use. In contrast, overweight youth were more likely to perceive their health as only fair or poor and were more likely to express weight-specific concerns and engage in behaviors such as chronic dieting and binge eating than nonoverweight youth. Overweight American Indian girls perceived their physical health more positively than nonoverweight American Indian girls. Strong associations were found between overweight status and chronic dieting among African American boys and girls. Conclusions: Nutritional counseling and educational programs need to address the weight-specific concerns and behaviors of overweight adolescents. However, assumptions regarding global psychosocial concerns and health-compromising behaviors among overweight adolescents of different genders and ethnicities should be avoided. These broad issues need to be explored in more depth at both the research and intervention levels.     

Neuropeptide messenger plasticity in the CNS neurons following axotomy

Neuronal peptides exert neurohormonal and neurotransmitter (neuromodulator) functions in the central nervous system (CNS). Besides these functions, a group of neuropeptides may have a capacity to create cell proliferation, growth, and survival. Axotomy induces transient (1–21 d) upregulation of synthesis and gene expression of neuropeptides, such as galanin, corticotropin releasing factor, dynorphin, calcitonin gene-related peptide, vasoactive intestinal polypeptide, cholecystokinin, angiotensin II, and neuropeptide Y. These neuropeptides are colocalized with “classic” neurotransmitters (acetylcholine, aspartate, glutamate) or neurohormones (vasopressin, oxytocin) that are downregulated by axotomy in the same neuronal cells. It is more likely that neuronal cells, in response to axotomy, increase expression of neuropeptides that promote their survival and regeneration, and may downregulate substances related to their transmitter or secretory activities.     

Modeling the leech heartbeat elemental oscillator I. Interactions of intrinsic and synaptic currents

We have developed a biophysical model of a pair of reciprocally inhibitory interneurons comprising an elemental heartbeat oscillator of the leech. We incorporate various intrinsic and synaptic ionic currents based on voltage-clamp data. Synaptic transmission between the interneurons consists of both a graded and a spike-mediated component. By using maximal conductances as parameters, we have constructed a canonical model whose activity appears close to the real neurons. Oscillations in the model arise from interactions between synaptic and intrinsic currents. The inhibitory synaptic currents hyperpolarize the cell, resulting in activation of a hyperpolarization-activated inward currentI _h and the removal of inactivation from regenerative inward currents. These inward currents depolarize the cell to produce spiking and inhibit the opposite cell. Spike-mediated IPSPs in the inhibited neuron cause inactivation of low-threshold Ca⁺⁺ currents that are responsible for generating the graded synaptic inhibition in the opposite cell. Thus, although the model cells can potentially generate large graded IPSPs, synaptic inhibition during canonical oscillations is dominated by the spike-mediated component.     

Mutations in neuromusculin,a gene encoding a cell adhesion molecule,cause nervous system defects

The Drosophila neuromusculin (nrm) gene encodes an immunoglobulin-like (Ig-like) cell adhesion molecule expressed in the precursors of the embryonic peripheral nervous system (PNS), in the midline precursors of the central nervous system (CNS), and in muscles. During the initial phases of CNS axonogenesis, nrm is expressed in cells involved in the development of commissures and longitudinal tracts. Mutations which alter expression of nrm mRNAs cause aberrant development of commissures and longitudinal axon pathways. Defects in the PNS and muscles of nrm mutants are also observed. In most nrm embryos, abnormal development can be detected in a subset of abdominal segments; however, in approximately 1 of 10 nrm embryos, the defects extend to all segments. Herein, we present evidence that nrm plays an important role in early morphogenesis, possibly by mediating or facilitating inductive cell contacts and movements.     

In vitro autoradiographic localization of vasoactive intestinal peptide (VIP) binding sites in the rat central nervous system

This paper describes the autoradiographic distribution of VIP binding sites in the rat central nervous system using monoiodinated ¹²³I-labeled VIP. High densities of VIP binding sites are observed in the granular layer of the dorsal dentate gyrus of the hippocampus, the basolateral amygdaloid nucleus, the dorsolateral and median geniculate nuclei of the thalamus as well as in the ventral part of the hypothalamic dorsomedial nucleus.     

Primary cultures of fetal hepatocytes from the genetically obese Zucker rat: Protein synthesis

Summary Primary fetal hepatocytes derived from Zucker rats with expectedfa gene frequencies of 0.0 and 0.75 have been established and can be used to detect early effects of thefa gene on hepatocellular metabolism. Paired incubation experiments demonstrate that protein synthesis in 0.75fa gene cultures is significantly less than in 0.0fa gene cultures under basal conditions. Insulin stimulates protein synthesis in 0.0fa gene cultures but has no effect on 0.75fa gene cultures. Cycloheximide inhibits protein synthesis in both types of culture. NH₄Cl inhibits protein synthesis in 0.0 but not in 0.75fa gene cultures. These data suggest that fetal hepatocytes bearing thefa gene have in vitro a generally sluggish anabolic capacity and a blunted capacity to respond to insulin compared to fetal hepatocytes without thefa gene. These diminished capacities may be expressions of a genetic error in lysosomal function. A portion of this work was presented in preliminary form at the 1980 meeting of the Tissue Culture Association. This work was supported in part by National Institutes of Health Grants AM19382 and AM06197.     

Microwave treatment of intracerebral l1210 leukemia: Schedule-dependent partial reversal of the effects of methotrexate

One-GHz microwave (MW) irradiation at a power density of 5 mW/cm² was combined with methotrexate (MTX) in an attempt to treat more effectively central nervous system (CNS) L1210 leukemia in DBA/2J mice. When mice with CNS leukemia were treated with the combination of MW and MTX, there was no improvement in survival compared with a group of animals treated with MTX alone; however, the group that received MTX before the MW exposure had a significantly reduced survival time compared with the group treated with MTX alone or with the group to which MTX was administered after MW.     

Hypothalamic and hormonal control of photoperiodically induced vernal functions in the white-crowned sparrow,Zonotrichia leucophrys gambelii

Summary The effects of implantation of testosterone propionate (TP) in various sites in the hypothalamus on the photoperiodically induced vernal premigratory functions in the White-crowned Sparrows were investigated in order to assess the role of the hypothalamo-hypophysial-testicular axis in the induction of these responses.Implantation of glass capillary tubes containing TP in the basal infundibular nucleus (IN), in the median eminence, or in the pars distalis inhibited the photoperiodically induced increase in plasma levels of luteinizing hormone (LH), as measured by radioimmunoassay, and testicular growth. The effective implants significantly lowered the levels of LH in birds held on nonstimulatory short days. These TP implants apparently inhibited release from the pars distalis of both LH and follicle-stimulating hormone (FSH). It is concluded that the site of sensitivity in the negative feedback by testosterone is either the basal IN or the pars distalis, or both. The implants of TP that inhibited the increase in plasma LH and testicular growth completely did not prevent the birds from fattening.These investigations were supported, in part, by research grants from the National Institutes of Health (HD-6527) and National Science Foundation (BMS 79-13933) to Professor Donald S. Farner. This paper is based on a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy from the University of WashingtonThe author is grateful to Professor Donald S. Farner for his guidance throughout the course of these investigations. The assistance of Mr. Philip W. Mattocks, Jr. in performing radioimmunoassays is sincerely appreciated     

Molecular cloning of unintegrated visna viral DNA and characterization of frequent deletions in the 3' terminus

Visna viral DNA, like other retroviral DNA, exists in two circular forms in infected cells. The larger probably contains two copies of the LTR, the smaller, one copy. Recombinant DNA techniques were used to clone unintegrated circular visna viral DNA in the lambda WES . lambda B vector. Circular visna viral DNA was digested with the restriction enzyme SstI, which yields a 9.2-kb viral DNA fragment containing 90% of the viral genome colinear with the restriction map of linear viral DNA. This fragment extends from a site about 900 bp from the left (5') end of the viral DNA molecule, through the 3' region, including U3 and R sequences at its right (3') end. The recombinant clones isolated contain visna viral DNA inserts which range in size from 3.1 kb to 9.2 kb. All the clones contain the 5' region intact, but most had sustained deletions of varying lengths in the 3' terminal region of the cloned fragment.     

An antigen present in the Drosophila central nervous system only during embryonic and metamorphic stages

We report here about an antigen that is expressed in the central nervous system (CNS) of Drosophila only during the embryonic and metamorphic stages. In Drosophila, axonogenesis and synaptogenesis occur twice during the development: first in the embryonic and second in the metamorphic stages. We generated monoclonal antibodies (MAbs) in order to obtain molecular probes for analyzing axonogenesis or synaptogenesis in the CNS on the assumption that good candidates for molecules responsible for such phenomena must be present in the neuropil during those stages exclusively. As a result, we found MAb 66B2 whose intense immunoreactivity in the neuropil of the CNS was observed exclusively in the embryo and pupa, and not in the larva and adult. Immunoblot analyses showed that MAb 66B2 binds specifically to a protein with an apparent molecular weight of 350 K and neutral pl in the prepupal CNS. A significant amount of the antigen was isolated in forms that were soluble without detergent. Results of immunohistochemistry with MAb 66B2 in a primary culture of embryos showed that some live cells in the ganglion-like cluster were stained, and that neuronal cell bodies and neurites emanating from there were negative. These results strongly suggest that the 66B2 antigen observed in the CNS is an extracellular matrix component secreted from nonneuronal cells. These developmental changes in the 66B2 immuno-reactivity in the CNS presumably reflect dynamic changes of an extracellular matrix in the CNS that are accompanied by axonogenesis or synaptogenesis. © 1992 John Wiley & Sons, Inc.