64 research outputs found
Characteristics and Predictors for Students Classified with Emotional and Behavioral Disorder Who Have Also Experienced Maltreatment
Though experiencing maltreatment (abuse or neglect) appears to be common in students with the special education label of emotional and behavioral disorders (EBD), little research has been devoted to this topic by EBD educators. This paper uses archived file drawer data from 1992 that focuses on 149 students newly classified with EBD for whom a wide range of enrollment variables was collected, and who were subsequently followed up on an average of 8 years later to assess their educational outcomes. At enrollment, experiences of maltreatment were determined to have occurred in 57.7% of these participants. The group who experienced maltreatment was predicted at enrollment only by the family stress of having at least one natural parent with a history of psychiatric illness, although the concordance was not strong (52.3%). When the children who experienced maltreatment were next divided into two longitudinal groups according to educational outcomes (52.3% successful), the enrollment variables of the presence of anxiety and/or depressive disorder and younger age predicted the successful outcome group with good concordance (76.0%). Professional and programmatic implications for educators of students identified with EBD who have also experienced maltreatment are discussed, along with practical recommendations for serving this population
New Clock Comparison Searches for Lorentz and CPT Violation
We present two new measurements constraining Lorentz and CPT violation using
the Xe-129 / He-3 Zeeman maser and atomic hydrogen masers. Experimental
investigations of Lorentz and CPT symmetry provide important tests of the
framework of the standard model of particle physics and theories of gravity.
The two-species Xe-129 / He-3 Zeeman maser bounds violations of CPT and Lorentz
symmetry of the neutron at the 10^-31 GeV level. Measurements with atomic
hydrogen masers provide a clean limit of CPT and Lorentz symmetry violation of
the proton at the 10^-27 GeV level.Comment: 11 pages, 5 figures. To appear in the Proceedings of the 3rd
International Symposium on Symmetries in Subatomic Physic
Osteocalcin signaling in myofibers is necessary and sufficient for optimum adaptation to exercise
Circulating levels of undercarboxylated and bioactive osteocalcin double during aerobic exercise at the time levels of insulin decrease. In contrast, circulating levels of osteocalcin plummet early during adulthood in mice, monkeys, and humans of both genders. Exploring these observations revealed that osteocalcin signaling in myofibers is necessary for adaptation to exercise by favoring uptake and catabolism of glucose and fatty acids, the main nutrients of myofibers. Osteocalcin signaling in myofibers also accounts for most of the exercise-induced release of interleukin-6, a myokine that promotes adaptation to exercise in part by driving the generation of bioactive osteocalcin. We further show that exogenous osteocalcin is sufficient to enhance the exercise capacity of young mice and to restore to 15-month-old mice the exercise capacity of 3-month-old mice. This study uncovers a bone-to-muscle feedforward endocrine axis that favors adaptation to exercise and can reverse the age-induced decline in exercise capacity
Teratology Primer-2nd Edition (7/9/2010)
Foreword:
What is Teratology?
βWhat a piece of work is an embryo!β as Hamlet might have said. βIn form and moving how express and admirable! In complexity how infinite!β It starts as a single cell, which by repeated divisions gives rise to many genetically identical cells. These cells receive signals from their surroundings and from one another as to where they are in this ball of cells βfront or back, right or left, headwards or tailwards, and what they are destined to become. Each cell commits itself to being one of many types; the cells migrate, combine into tissues, or get out of the way by dying at predetermined times and places. The tissues signal one another to take their own pathways; they bend, twist, and form organs. An organism emerges. This wondrous transformation from single celled simplicity to myriad-celled complexity is programmed by genes that, in the greatest mystery of all, are turned on and off at specified times and places to coordinate the process. It is a wonder that this marvelously emergent operation, where there are so many opportunities for mistakes, ever produces a well-formed and functional organism.
And sometimes it doesnβt. Mistakes occur. Defective genes may disturb development in ways that lead to death or to malformations. Extrinsic factors may do the same. βTeratogenicβ refers to factors that cause malformations, whether they be genes or environmental agents. The word comes from the Greek βteras,β for βmonster,β a term applied in ancient times to babies with severe malformations, which were considered portents or, in the Latin, βmonstra.β
Malformations can happen in many ways. For example, when the neural plate rolls up to form the neural tube, it may not close completely, resulting in a neural tube defectβanencephaly if the opening is in the head region, or spina bifida if it is lower down. The embryonic processes that form the face may fail to fuse, resulting in a cleft lip. Later, the shelves that will form the palate may fail to move from the vertical to the horizontal, where they should meet in the midline and fuse, resulting in a cleft palate. Or they may meet, but fail to fuse, with the same result. The forebrain may fail to induce the overlying tissue to form the eye, so there is no eye (anophthalmia). The tissues between the toes may fail to break down as they should, and the toes remain webbed.
Experimental teratology flourished in the 19th century, and embryologists knew well that the development of bird and frog embryos could be deranged by environmental βinsults,β such as lack of oxygen (hypoxia). But the mammalian uterus was thought to be an impregnable barrier that would protect the embryo from such threats. By exclusion, mammalian malformations must be genetic, it was thought.
In the early 1940s, several events changed this view. In Australia an astute ophthalmologist, Norman Gregg, established a connection between maternal rubella (German measles) and the triad of cataracts, heart malformations, and deafness. In Cincinnati Josef Warkany, an Austrian pediatrician showed that depriving female rats of vitamin B (riboflavin) could cause malformations in their offspringβ one of the early experimental demonstrations of a teratogen. Warkany was trying to produce congenital cretinism by putting the rats on an iodine deficient diet. The diet did indeed cause malformations, but not because of the iodine deficiency; depleting the diet of iodine had also depleted it of riboflavin!
Several other teratogens were found in experimental animals, including nitrogen mustard (an anti cancer drug), trypan blue (a dye), and hypoxia (lack of oxygen). The pendulum was swinging back; it seemed that malformations were not genetically, but environmentally caused.
In Montreal, in the early 1950s, Clarke Fraserβs group wanted to bring genetics back into the picture. They had found that treating pregnant mice with cortisone caused cleft palate in the offspring, and showed that the frequency was high in some strains and low in others. The only difference was in the genes. So began βteratogenetics,β the study of how genes influence the embryoβs susceptibility to teratogens.
The McGill group went on to develop the idea that an embryoβs genetically determined, normal, pattern of development could influence its susceptibility to a teratogenβ the multifactorial threshold concept. For instance, an embryo must move its palate shelves from vertical to horizontal before a certain critical point or they will not meet and fuse. A teratogen that causes cleft palate by delaying shelf movement beyond this point is more likely to do so in an embryo whose genes normally move its shelves late.
As studies of the basis for abnormal development progressed, patterns began to appear, and the principles of teratology were developed. These stated, in summary, that the probability of a malformation being produced by a teratogen depends on the dose of the agent, the stage at which the embryo is exposed, and the genotype of the embryo and mother.
The number of mammalian teratogens grew, and those who worked with them began to meet from time to time, to talk about what they were finding, leading, in 1960, to the formation of the Teratology Society. There were, of course, concerns about whether these experimental teratogens would be a threat to human embryos, but it was thought, by me at least, that they were all βsledgehammer blows,β that would be teratogenic in people only at doses far above those to which human embryos would be exposed. So not to worry, or so we thought.
Then came thalidomide, a totally unexpected catastrophe. The discovery that ordinary doses of this supposedly βharmlessβ sleeping pill and anti-nauseant could cause severe malformations in human babies galvanized this new field of teratology. Scientists who had been quietly working in their laboratories suddenly found themselves spending much of their time in conferences and workshops, sitting on advisory committees, acting as consultants for pharmaceutical companies, regulatory agencies, and lawyers, as well as redesigning their research plans.
The field of teratology and developmental toxicology expanded rapidly. The following pages will show how far we have come, and how many important questions still remain to be answered. A lot of effort has gone into developing ways to predict how much of a hazard a particular experimental teratogen would be to the human embryo (chapters 9β19). It was recognized that animal studies might not prove a drug was βsafeβ for the human embryo (in spite of great pressure from legislators and the public to do so), since species can vary in their responses to teratogenic exposures. A number of human teratogens have been identified, and some, suspected of teratogenicity, have been exoneratedβat least of a detectable risk (chapters 21β32). Regulations for testing drugs before market release have greatly improved (chapter 14). Other chapters deal with how much such things as population studies (chapter 11), post-marketing surveillance (chapter 13), and systems biology (chapter 16) add to our understanding. And, in a major advance, the maternal role of folate in preventing neural tube defects and other birth defects is being exploited (chapter 32). Encouraging women to take folic acid supplements and adding folate to flour have produced dramatic falls in the frequency of neural tube defects in many parts of the world.
Progress has been made not only in the use of animal studies to predict human risks, but also to illumine how, and under what circumstances, teratogens act to produce malformations (chapters 2β8). These studies have contributed greatly to our knowledge of abnormal and also normal development. Now we are beginning to see exactly when and where the genes turn on and off in the embryo, to appreciate how they guide development and to gain exciting new insights into how genes and teratogens interact. The prospects for progress in the war on birth defects were never brighter.
F. Clarke Fraser McGill University (Emeritus) Montreal, Quebec, Canad
Regulation of the Escherichia coli HipBA Toxin-Antitoxin System by Proteolysis
Bacterial populations produce antibiotic-tolerant persister cells. A number of recent studies point to the involvement of toxin/antitoxin (TA) modules in persister formation. hipBA is a type II TA module that codes for the HipB antitoxin and the HipA toxin. HipA is an EF-Tu kinase, which causes protein synthesis inhibition and dormancy upon phosphorylation of its substrate. Antitoxins are labile proteins that are degraded by one of the cytosolic ATP-dependent proteases. We followed the rate of HipB degradation in different protease deficient strains and found that HipB was stabilized in a lon- background. These findings were confirmed in an in vitro degradation assay, showing that Lon is the main protease responsible for HipB proteolysis. Moreover, we demonstrated that degradation of HipB is dependent on the presence of an unstructured carboxy-terminal stretch of HipB that encompasses the last 16 amino acid residues. Further, substitution of the conserved carboxy-terminal tryptophan of HipB to alanine or even the complete removal of this 16 residue fragment did not alter the affinity of HipB for hipBA operator DNA or for HipA indicating that the major role of this region of HipB is to control HipB degradation and hence HipA-mediated persistence
Types of Language Disorders in Students Classified as ED: Prevalence and Association with Learning Disabilities and Psychopathology
The purpose of this study was to determine the prevalence of four types of language disorders among public school students (N = 152) classified as Emotional Disturbance (ED). We also examined the association of the types of language disorders experienced by these students with specific learning disabilities and clinical levels of specific types of psychopathology. Nearly 66% of the students with ED experienced a language disorder, with combined receptive-expressive disorders being the most common (35.5%). Students with a language disorder, particularly combined receptive-expressive disorder, showed significantly poorer achievement and more learning disabilities (LD) in all areas compared to students with no language disorder. Furthermore, 91.3% of the students with any LD also had a language disorder. Types of language disorders were not significantly distinguished by psychopathology, although severity was serious in both students with and without a language disorder. These findings have implications for the identification and treatment of language disorders in students classified ED
Mother, Father, and Teacher Agreement on Victimization and Bullying in Children With Psychiatric Disorders
Psychotropic Medication Characteristics for Special Education Students with Emotional and/or Behavioral Disorders
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