ABSTRACT
Posttraumatic stress disorder (PTSD) is a chronic anxiety disorder that follows exposure to extreme events. A large twin study of Vietnam veterans had demonstrated a significant genetic contribution to chronic PTSD upon exposure to combat.(1,2) The underlying genes, however, have not been described. Given previous findings of abnormal dopamine (DA) function in PTSD, and given the putative effect of dopamine neurotransmission in shaping the responses to stress in animals, this study examined the association of the dopamine transporter (DAT) SLC6A3 3' variable number tandem repeat (VNTR) polymorphism with PTSD. The study evaluated 102 chronic PTSD patients and 104 carefully-documented trauma survivors (TS) who did not develop PTSD. Significant excess of 9 repeat allele was observed among PTSD patients (43% vs 30.5% in TS controls; chi(2) = 6.3, df = 1, P = 0.012). An excess of 9 repeat homozygous genotype was also observed in PTSD (20.43% in PTSD vs 9.47% in TS controls; chi(2) = 6.11, df = 2, P < 0.047). These findings suggest that genetically determined changes in dopaminergic reactivity may contribute to the occurrence of PTSD among trauma survivors.
Subject(s)
Membrane Glycoproteins , Membrane Transport Proteins/genetics , Nerve Tissue Proteins , Stress Disorders, Post-Traumatic/genetics , Adult , Brain Chemistry/genetics , Dopamine Plasma Membrane Transport Proteins , Female , Gene Frequency , Genotype , Humans , Male , Middle AgedABSTRACT
Crystals suitable for X-ray study have been prepared from biochemically active ribosome particles or their complexes with tRNA and polypeptide chains. At ambient temperature the useful lifetime of these crystals under synchrotron irradiation is limited to a few minutes. However, upon cooling to cryogenic temperatures around 85 K, the original resolution limit (up to 4.5 A) can be recorded and radiation damage is virtually eliminated. Hence it has become possible to collect a complete data set from one single crystal. Crystals were cooled as rapidly as possible, either in a cold gas stream, or by immersion in liquid propane. Before cooling crystals were transferred either to an inert hydrocarbon environment, or to solutions similar to the crystallizing ones but with a higher viscosity. In several cases soaking in a cryosolvent was required. Crystallographic data were collected with intense synchrotron radiation. Full data sets have been measured for native and derivatized crystals of 50S ribosomal subunits from H. marismortui as well as from their complexes with tRNA and nascent polypeptide chains, from the wild type and a mutant of 50S subunits from B. stearothermophilus, and from crystals of native and derivatized 30S ribosomal subunits from T. thermophilus.
Subject(s)
Ribosomes/ultrastructure , Bacteria/ultrastructure , Crystallography/instrumentation , Microscopy, Electron , X-Ray DiffractionABSTRACT
Reports of a series of item and factor analyses of a number of sentence-completion and multiple-choice measures of autonomy in children are presented. Factors suggested in early versions of the tests were strengthened in later versions. Various factor analyses were performed on 2041 children averaging age 12, using four separate and progressive versions of the measure. Autonomy was differentiated into independence when faced with obstacles, in the face of parental pressure, in the face of peer pressure, and in traumatic situations. The results are discussed as supporting the interactionist position in the situation-specific and trans-situational trait-consistency controversy.
