Guidelines for healthy children: promoting eating, moving, and common sense.
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Adult↗
Biomedical subjects
S L Johnson
Publications and source records attributed to S L Johnson.
Social support and self-esteem predict changes in bipolar depression but not mania.
INTRODUCTION: Our own and other research has suggested that social support predicts course of bipolar disorder, with particularly strong effects on depressive symptoms. Within this paper, we examine which components of social support appear most powerful. METHODS: Thirty-one individuals with Bipolar I disorder were followed longitudinally for 9 months. Participants completed a standardized symptom severity interview monthly, and at a 2-month follow-up, they completed the Interpersonal Support Evaluation List. At a 6-month follow-up, they completed the Rosenberg Self-Esteem Inventory. RESULTS: Self-esteem support appeared to the most important predictor of change in depression across a 6-month follow-up, and multiple regression analyses suggested that social support effects were mediated through self-esteem. LIMITATIONS AND IMPLICATIONS: Although the small sample size suggests a need for replication, current results highlight the importance of psychosocial variables in the course of bipolar depression. Self-esteem may be a particularly important target for clinical interventions.
Adult↗
Sequential interactions in the marital communication of depressed men and women.
Despite studies showing patterns of sequential interaction between depressed wives and their husbands, no published research has contrasted sequential interactions of depressed husbands and their wives. This study compared problem-solving interactions of 49 couples with a depressed husband, 41 with a depressed wife, and 50 normal controls. Interactions were coded using the Marital Interaction Coding System. Although no clear patterns of sequential interaction distinguished couples with a depressed wife from normal control couples, results suggested a unique pattern of interaction between depressed husbands and their spouses, whereby positive communications from the husband resulted in decreased positivity and increased negativity from their wives. Given the importance of positivity for promoting effective problem solving, this pattern appears to have important implications for couples' long-term marital satisfaction and husbands' mood regulation.
Adult↗
Genetic linkage mapping of zebrafish genes and ESTs.
Genetic screens in zebrafish (Danio rerio) have isolated mutations in hundreds of genes essential for vertebrate development, physiology, and behavior. We have constructed a genetic linkage map that will facilitate the identification of candidate genes for these mutations and allow comparisons among the genomes of zebrafish and other vertebrates. On this map, we have localized 771 zebrafish genes and expressed sequence tags (ESTs) by scoring single-stranded conformational polymorphisms (SSCPs) in a meiotic mapping panel. Of these sequences, 642 represent previously unmapped genes and ESTs. The mapping panel was comprised of 42 homozygous diploid individuals produced by heat shock treatment of haploid embryos at the one-cell stage (HS diploids). This "doubled haploid" strategy combines the advantages of mapping in haploid and standard diploid systems, because heat shock diploid individuals have only one allele at each locus and can survive to adulthood, enabling a relatively large quantity of genomic DNA to be prepared from each individual in the mapping panel. To integrate this map with others, we also scored 593 previously mapped simple-sequence length polymorphisms (SSLPs) in the mapping panel. This map will accelerate the molecular analysis of zebrafish mutations and facilitate comparative analysis of vertebrate genomes.
Animals↗
Human and behavioral factors contributing to spine-based neurological cockpit injuries in pilots of high-performance aircraft: recommendations for management and prevention.
In high-performance aircraft, the need for total environmental awareness coupled with high-g loading (often with abrupt onset) creates a predilection for cervical spine injury while the pilot is performing routine movements within the cockpit. In this study, the prevalence and severity of cervical spine injury are assessed via a modified cross-sectional survey of pilots of multiple aircraft types (T-38 and F-14, F-16, and F/A-18 fighters). Ninety-five surveys were administered, with 58 full responses. Fifty percent of all pilots reported in-flight or immediate post-flight spine-based pain, and 90% of fighter pilots reported at least one event, most commonly (> 90%) occurring during high-g (> 5 g) turns of the aircraft with the head deviated from the anatomical neutral position. Pre-flight stretching was not associated with a statistically significant reduction in neck pain episodes in this evaluation, whereas a regular weight training program in the F/A-18 group approached a significant reduction (mean = 2.492; p < 0.064). Different cockpit ergonomics may vary the predisposition to cervical injury from airframe to airframe. Several strategies for prevention are possible from both an aircraft design and a preventive medicine standpoint. Countermeasure strategies against spine injury in pilots of high-performance aircraft require additional research, so that future aircraft will not be limited by the human in control.
Adult↗
Gene duplication of zebrafish JAK2 homologs is accompanied by divergent embryonic expression patterns: only jak2a is expressed during erythropoiesis.
Members of the JAK family of protein tyrosine kinase (PTK) proteins are required for the transmission of signals from a variety of cell surface receptors, particularly those of the cytokine receptor family. JAK function has been implicated in hematopoiesis and regulation of the immune system, and recent data suggest that the vertebrate JAK2 gene may play a role in leukemia. We have isolated and characterized jak cDNAs from the zebrafish Danio rerio. The zebrafish genome possesses 2 jak2 genes that occupy paralogous chromosome segments in the zebrafish genome, and these segments conserve syntenic relationships with orthologous genes in mammalian genomes, suggesting an ancient duplication in the zebrafish lineage. The jak2a gene is expressed at high levels in erythroid precursors of primitive and definitive waves and at a lower level in early central nervous system and developing fin buds. jak2b is expressed in the developing lens and nephritic ducts, but not in hematopoietic tissue. The expression of jak2a was examined in hematopoietic mutants and found to be disrupted in cloche and spadetail, suggesting an early role in hematopoiesis. Taken together with recent gene knockout data in the mouse, we suggest that jak2a may be functionally equivalent to mammalian Jak2, with a role in early erythropoiesis.
Alleles↗
Radiation hybrid mapping of the zebrafish genome.
The zebrafish is an excellent genetic system for the study of vertebrate development and disease. In an effort to provide a rapid and robust tool for zebrafish gene mapping, a panel of radiation hybrids (RH) was produced by fusion of irradiated zebrafish AB9 cells with mouse B78 cells. The overall retention of zebrafish sequences in the 93 RH cell lines that constitute the LN54 panel is 22%. Characterization of the LN54 panel with 849 simple sequence length polymorphism markers, 84 cloned genes and 122 expressed sequence tags allowed the production of an RH map whose total size was 11,501 centiRays. From this value, we estimated the average breakpoint frequency of the LN54 RH panel to correspond to 1 centiRay = 148 kilobase. Placement of a group of 235 unbiased markers on the RH map suggests that the map generated for the LN54 panel, at present, covers 88% of the zebrafish genome. Comparison of marker positions in RH and meiotic maps indicated a 96% concordance. Mapping expressed sequence tags and cloned genes by using the LN54 panel should prove to be a valuable method for the identification of candidate genes for specific mutations in zebrafish.
Animals↗
Axonal regeneration in the central nervous system of aplysia californica determined by anterograde transport of biocytin.
Rhythmic biting, a component of consummatory feeding behavior in the sea hare Aplysia californica, is eliminated following bilateral cerebral-buccal connective (CBC) crushes and recovers within 14 days postlesion. To assess axonal regeneration after CBC lesions, we used biocytin backfills of CBCs followed by fluorescence labeling with streptavidin-lissamine rhodamine. Anterograde transport of biocytin showed up to 1 mm of outgrowth by regenerating axons at 3 days postlesion. At 7 days postlesion, the regenerated axons approached or had entered the ipsilateral buccal neuropil and exhibited numerous varicosities; the average rate of axonal growth was 326 microm/day for the longest, most rapidly growing axons labeled in the CBC. The number of varicosities on labeled axons, suggestive of intercellular interactions, was increased dramatically at all times postlesion. At 14 and 20 days postlesion, regenerated axons branched extensively in the ipsilateral buccal neuropil, entered the contralateral buccal neuropil, and entered peripheral nerves on both sides of the midline. At these later times postlesion, some labeled axons encircled unlabeled buccal cell bodies and exhibited branches containing numerous varicosities, indicative of axosomatic contacts. Some regenerating axons were observed in the sheath of the CBC, but the vast majority of labeled axons remained confined to the connective core, as in control preparations. The bilateral projections within the buccal ganglia of labeled cerebral-to-buccal axons and the large number of varicosities present on these processes are indicative of regenerating axons and synapses that likely contribute to the functional recovery of rhythmic biting.
Animals↗
Notochordal cells interact with nucleus pulposus cells: regulation of proteoglycan synthesis.
The disappearance of notochordal cells is correlated with early degenerative changes in the intervertebral disc. With increased disc degeneration there is a marked decrease in proteoglycan synthesis, resulting in loss of mechanical function. One possible mechanism for the decrease in proteoglycan synthesis is the loss of notochordal cells from the tissue. In this study, nucleus pulposus cells cocultured with notochordal cells exhibit an increase in proteoglycan synthesis. Interestingly, purified notochordal cells synthesize little proteoglycan as observed by [35S]sulfate incorporation into proteoglycans. The observed increase in proteoglycan synthesis does not appear to be dependent on cell-cell contact; rather it is the result of soluble factor(s) produced by notochordal cells. Finally, no difference in chondroitin sulfate chain size in notochordal-stimulated nucleus pulposus cells was observed which is consistent with an up-regulation in aggrecan core protein synthesis. These results are consistent with canine breeds where notochordal cells persist into adult age and disc degeneration is not observed. This suggests notochordal cells play a vital role in maintaining disc integrity.
Aggrecans↗
Zebrafish stat3 is expressed in restricted tissues during embryogenesis and stat1 rescues cytokine signaling in a STAT1-deficient human cell line.
Transcription factors of the STAT family are required for cellular responses to multiple signaling molecules. After ligand binding-induced activation of cognate receptors, STAT proteins are phosphorylated, hetero- or homodimerize, and translocate to the nucleus. Subsequent STAT binding to specific DNA elements in the promoters of signal-responsive genes alters the transcriptional activity of these loci. STAT function has been implicated in the transduction of signals for growth, reproduction, viral defense, and immune regulation. We have isolated and characterized two STAT homologs from the zebrafish Danio rerio. The stat3 gene is expressed in a tissue-restricted manner during embryogenesis, and larval development with highest levels of transcript are detected in the anterior hypoblast, eyes, cranial sensory ganglia, gut, pharyngeal arches, cranial motor nuclei, and lateral line system. In contrast, the stat1 gene is not expressed during early development. The stat3 gene maps to a chromosomal position syntenic with the mouse and human STAT3 homologs, whereas the stat1 gene does not. Despite a higher rate of evolutionary change in stat1 relative to stat3, the stat1 protein rescues interferon-signaling functions in a STAT1-deficient human cell line, indicating that cytokine-signaling mechanisms are likely to be conserved between fish and tetrapods. Dev Dyn 1999;215:352-370.
Amino Acid Sequence↗
Growth control in the ontogenetic and regenerating zebrafish fin.
The growth and regeneration of the zebrafish fin provide yet another opportunity to exploit genetics to study important vertebrate problems. Mutants have been identified in zebrafish that affect the development of the embryonic fin, disrupt the normal growth relationship of fin and body, or disrupt the regeneration of the fin. Analysis of a regeneration mutation suggests that the developmental checkpoints that ensure developmental integrity in normal growth are absent in the early stages of regeneration. These stages correspond to the only time in fish developmental when differentiated bone cells divide.
Animals↗
Genetic backgrounds and some standard stocks and strains used in zebrafish developmental biology and genetics.
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Animals↗
Social support and the course of bipolar disorder.
The current study prospectively examined the impact of social support on symptom severity and recovery from episodes in bipolar disorder, both as a direct influence and as a buffer of life events. Fifty-nine individuals with Bipolar I disorder were followed longitudinally with monthly symptom severity interviews. Social support was measured by the Interpersonal Support Evaluation List and the Interview Schedule for Social Interaction, and life events were assessed using the Life Events and Difficulties Schedule. Individuals with low social support took longer to recover from episodes and were more symptomatic across a 6-month follow-up. Results suggest a polarity-specific effect, in that social support influences depression but not mania. Discussion focuses on theoretical implications of a series of polarity-specific findings within the field.
Adult↗
Assessment of polymorphism in zebrafish mapping strains.
To assess the level of heterozygosity within two commonly used inbred mapping zebrafish strains, C32 and SJD, we genotyped polymorphic CA-repeat markers randomly dispersed throughout the zebrafish genome. (For clarity purposes we will primarily use the term polymorphic to define polymorphism between strains, and the term heterozygous to address heterogeneity within a strain.) Eight male individuals each from C32 and SJD stocks were typed for 235 and 183 markers, respectively. Over 90% of the markers typed were polymorphic between these two strains. We found a limited number of heterozygous markers persisting in clusters within each inbred line. In the SJD strain, these were mainly limited to a few telomeric regions or regions otherwise distant from centromeres. As expected, centromeric regions were homozygous in the SJD strain, consistent with its derivation from a single half-tetrad individual. In contrast, heterozygous clusters were distributed randomly throughout the genome in the C32 strain, and these clusters could be detected with linked polymorphic markers. Nevertheless, most regions of the C32 strain are homozygous for CA-repeat markers in current stocks. This identification of the heterozygous regions within C32 and SJD lines should permit rapid fixation of these remaining regions in future generations of inbreeding. In addition, we established levels of polymorphism between the inbred, C32 and SJD, strains and three other commonly used strains, the *AB, WIK, and Florida wild type (hereafter referred as EKK), with CA-repeat markers as well as SSCP polymorphisms. These data will maximize the use of these strains in mapping experiments.
Animals↗
Zebrafish sparse corresponds to an orthologue of c-kit and is required for the morphogenesis of a subpopulation of melanocytes, but is not essential for hematopoiesis or primordial germ cell development.
The relative roles of the Kit receptor in promoting the migration and survival of amniote melanocytes are unresolved. We show that, in the zebrafish, Danio rerio, the pigment pattern mutation sparse corresponds to an orthologue of c-kit. This finding allows us to further elucidate morphogenetic roles for this c-kit-related gene in melanocyte morphogenesis. Our analyses of zebrafish melanocyte development demonstrate that the c-kit orthologue identified in this study is required both for normal migration and for survival of embryonic melanocytes. We also find that, in contrast to mouse, the zebrafish c-kit gene that we have identified is not essential for hematopoiesis or primordial germ cell development. These unexpected differences may reflect evolutionary divergence in c-kit functions following gene duplication events in teleosts.
Animals↗
nacre encodes a zebrafish microphthalmia-related protein that regulates neural-crest-derived pigment cell fate.
We report the isolation and identification of a new mutation affecting pigment cell fate in the zebrafish neural crest. Homozygous nacre (nac(w2)) mutants lack melanophores throughout development but have increased numbers of iridophores. The non-crest-derived retinal pigment epithelium is normal, suggesting that the mutation does not affect pigment synthesis per se. Expression of early melanoblast markers is absent in nacre mutants and transplant experiments suggested a cell-autonomous function in melanophores. We show that nac(w2) is a mutation in a zebrafish gene encoding a basic helix-loop-helix/leucine zipper transcription factor related to microphthalmia (Mitf), a gene known to be required for development of eye and crest pigment cells in the mouse. Transient expression of the wild-type nacre gene restored melanophore development in nacre(-/-) embryos. Furthermore, misexpression of nacre induced the formation of ectopic melanized cells and caused defects in eye development in wild-type and mutant embryos. These results demonstrate that melanophore development in fish and mammals shares a dependence on the nacre/Mitf transcription factor, but that proper development of the retinal pigment epithelium in the fish is not nacre-dependent, suggesting an evolutionary divergence in the function of this gene.
Amino Acid Sequence↗
Cloning and genetic mapping of zebrafish BMP-2.
The BMP family of polypeptide growth factors has been shown to play diverse roles in establishing embryonic patterning and tissue fates. We report the cloning of the zebrafish homologue of BMP-2, examine its expression during embryogenesis, and find that it is localized to the distal end of the long arm of zebrafish chromosome 20. A missense mutation of the bmp2 gene has recently been shown to be responsible for the early dorsalized phenotype of the zebrafish swirl mutant [Kishimoto et al., 1997]. Given the dynamic expression of bmp2 in the developing embryo and the complex interactions of BMP signaling response in vertebrates, it is possible that other mutant phenotypes, due to altered bmp2 gene expression, will eventually map to or interact with this genetic locus.
Amino Acid Sequence↗
Vertebrate genome evolution and the zebrafish gene map.
In chordate phylogeny, changes in the nervous system, jaws, and appendages transformed meek filter feeders into fearsome predators. Gene duplication is thought to promote such innovation. Vertebrate ancestors probably had single copies of genes now found in multiple copies in vertebrates and gene maps suggest that this occurred by polyploidization. It has been suggested that one genome duplication event occurred before, and one after the divergence of ray-finned and lobe-finned fishes. Holland et al., however, have argued that because various vertebrates have several HOX clusters, two rounds of duplication occurred before the origin of jawed fishes. Such gene-number data, however, do not distinguish between tandem duplications and polyploidization events, nor whether independent duplications occurred in different lineages. To investigate these matters, we mapped 144 zebrafish genes and compared the resulting map with mammalian maps. Comparison revealed large conserved chromosome segments. Because duplicated chromosome segments in zebrafish often correspond with specific chromosome segments in mammals, it is likely that two polyploidization events occurred prior to the divergence of fish and mammal lineages. This zebrafish gene map will facilitate molecular identification of mutated zebrafish genes, which can suggest functions for human genes known only by sequence.
Animals↗