Genetic load is associated with hypothalamic-pituitary-adrenal axis dysregulation in macaques.

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis pathway is associated with several neuropsychiatric disorders, including post-traumatic stress disorder (PTSD), major depressive disorder (MDD), schizophrenia and alcohol abuse. Studies have demonstrated an association between HPA axis dysfunction and gene variants within the cortisol, serotonin and opioid signaling pathways. We characterized polymorphisms in genes linked to these three neurotransmitter pathways and tested their potential interactions with HPA axis activity, as measured by dexamethasone (DEX) suppression response. We determined the percent DEX suppression of adrenocorticotropic hormone (ACTH) and cortisol in 62 unrelated, male rhesus macaques. While DEX suppression of cortisol was robust amongst 87% of the subjects, ACTH suppression levels were broadly distributed from -21% to 66%. Thirty-seven monkeys from the high and low ends of the ACTH suppression distribution (18 'high' and 19 'low' animals) were genotyped at selected polymorphisms in five unlinked genes (rhCRH, rhTPH2, rhMAOA, rhSLC6A4 and rhOPRM). Associations were identified between three variants (rhCRH-2610C>T, rhTPH2 2051A>C and rh5-HTTLPR) and level of DEX suppression of ACTH. In addition, a significant additive effect of the 'risk' genotypes from these three loci was detected, with an increasing number of 'risk' genotypes associated with a blunted ACTH response (P = 0.0009). These findings suggest that assessment of multiple risk alleles in serotonin and cortisol signaling pathway genes may better predict risk for HPA axis dysregulation and associated psychiatric disorders than the evaluation of single gene variants alone.

A study of stigmatized attitudes towards people with mental health problems among health professionals.

The project aimed to assess stigmatized attitudes among health professionals directed towards patients with mental health problems. The Attitude to Mental Illness Questionnaire was used to assess participants' attitudes towards fictitious patients from a secure forensic hospital and patients with schizophrenia and substance use disorders. Participants were health professionals from acute and mental health settings. In total, 108 completed questionnaires were received. Participants had highly stigmatized attitudes towards patients from a forensic hospital and those with active substance use disorders. Attitudes were less stigmatized to people with substance use disorders who were recovering in remission. This suggested that health professionals have stigmatized attitudes towards an illness such as schizophrenia and this is worse towards patients from a secure hospital. The manner in which patients with substance use disorder are presented can have a significant effect on stigmatized attitudes by health professionals.

Preferential publication of editorial board members in medical specialty journals.

BACKGROUND: Publication bias and discrimination are increasingly recognised in medicine. A survey was conducted to determine if medical journals were more likely to publish research reports from members of their own than a rival journal's editorial board. METHODS: A retrospective review was conducted of all research reports published in 2006 in the four competing medical journals within five medical specialties. Only three journals were willing to divulge the authorship of reports that had been rejected. RESULTS: Overall, 4460 research reports were published in 2006 by the 20 journals from five subspecialties (mean 223 (SD = 164) reports per journal; median 176; interquartile range 108-238). On average, 17.2 (7.7%) reports were from a journal's own editorial board (SD = 10.7; median 15; interquartile range 10-23; n = 20), and 6.3 (2.8%) reports were from a member of the editorial board of one of the three rival journals within the specialty (SD = 7.3; median 3.5; interquartile range 1-8; n = 60). There was a statistically significant excess of publications from the journal's own editorial board in 14 of the 20 journals (p<0.05). Journals were almost three times more likely to publish reports from their own editorial board than from one of the three rivals within their subspecialty (p<0.0001; median difference 11; Mann-Whitney U test; power for 5% significance >99.99%). CONCLUSIONS: There was a significant excess of publications from medical journals' own editorial boards, although it is not possible to determine whether this is due to bias in the peer review process or selective submission by editors.

Characteristics of patients who are violent to staff and towards other people from a community mental health service in South East England.

Professionals working in the public sector in the UK report widespread violence towards staff working in areas such as health care, social services and education. This study compares the characteristics of patients with and without a history of violence in a large sample of patients attending a community mental health service in South East England. The data were taken from a study of comorbidity and cannabis use in a mental health trust covering a semi-rural population of 250,000 people in Harlow and the surrounding area of South East England. Key workers were interviewed using semi-structured questionnaires from the Comorbidity of Substance Misuse and Mental illness in Community Mental Health and Substance Misuse Services study. Rates of violence against health workers were more than 20 times higher among those patients with a history of violence (23.6% vs. 1%, P<0.001). Alcohol and drug use was more frequent in those who were violent. Prevalence of comorbidity, schizophrenia and personality disorders was high. Key workers' estimates suggested that there was no difference in aggression, engagement or adherence to care plan among those with a history of violence.

Somatostatin receptor desensitization in NG108-15 cells. A consequence of receptor sequestration.

In NG108-15 cells inhibition of both N-type calcium channel current and adenylyl cyclase by somatostatin (SRIF) was not sustained but rapidly desensitized in the continued presence of the drug. The degree and rate of desensitization were concentration-dependent, and the desensitization was homologous with respect to the delta-opioid receptor. We have been unable to obtain evidence for the involvement of G protein-coupled receptor kinases (GRKs) in this desensitization. SRIF-induced desensitization of N-type calcium channel currents was not reduced in cells stably overexpressing a dominant negative mutant of GRK2 or following intracellular dialysis with GRK2- and GRK3-blocking peptides or with heparin. Inhibitors of protein kinase A, protein kinase C, and protein kinase G were also without effect. In contrast, both the rate and degree of SRIF-induced desensitization were reduced by pretreatment with phenylarsine oxide or concanavalin A, both inhibitors of receptor endocytosis. Furthermore, SRIF-induced desensitization was enhanced by monensin, which prevents receptor recycling back to the plasma membrane. Similarly, SRIF-induced desensitization of adenylyl cyclase inhibition was not reduced in cells stably overexpressing dominant negative mutant GRK2 but was reduced in cells pretreated with the receptor endocytosis inhibitor hyperosmotic sucrose or concanavalin A. These data are consistent with the view that SRIF-induced desensitization in NG108-15 cells results from receptor internalization.

Enhanced expression of G protein-coupled receptor kinase 2 selectively increases the sensitivity of A2A adenosine receptors to agonist-induced desensitization.

1. G protein-coupled receptor kinases (GRKs) are thought to be important in mediating the agonist-induced phosphorylation and consequent desensitization of G protein-coupled receptor (GPCR) responses. We have previously shown that stable expression of a dominant negative mutant G protein-coupled receptor kinase 2 (GRK2) construct in NG108-15 mouse neuroblastoma x rat glioma cells suppresses the agonist-induced desensitization of A2A and A2B adenosine receptor-stimulated adenylyl cyclase activity (Mundell et al., 1997). To further determine the role of GRK2 in agonist-induced desensitization of these adenosine receptors, we stably overexpressed wild type GRK2 in NG108-15 cells. 2. In homogenates prepared from cells overexpressing GRK2, the acute stimulation of adenylyl cyclase by activation of A2A and A2B adenosine receptors was markedly reduced, but could be reversed by pretreating the cells with AD (adenosine deaminase), to remove extracellular adenosine from the medium. On the other hand, acute stimulation of adenylyl cyclase by secretin, iloprost, NaF and forskolin was the same in GRK2 overexpressing cells and plasmid-transfected control cells. 3. Cells overexpressing GRK2 were more sensitive to adenosine receptor agonist-induced desensitization than plasmid-transfected control cells. This effect was selective since the agonist sensitivity of desensitization for secretin and IP-prostanoid receptor-stimulated adenylyl cyclase activity was not affected by GRK2 overexpression. 4. These results further implicate GRK2 as the likely mechanism by which A2 adenosine receptors undergo short-term desensitization in NG108-15 cells, and indicate that even when overexpressed, GRK2 retains its substrate specificity for native receptors in intact cells. Furthermore, the susceptibility of GPCRs to desensitization appears to depend on the level of GRK expression, such that in cells that express high levels of GRK2, low agonist concentrations may be sufficient to trigger GRK-mediated desensitization.

Localization of the highly polymorphic microsatellite DXS456 on the genetic linkage map of the human X chromosome.

The CA repeat microsatellite DXS456, with a heterozygosity of 77%, has been localized by multipoint linkage analysis in relation to 20 other genetic markers. DXS456 mapped to a 4.2-cM interval defined by the flanking markers DXS178 and DXS287. The maximum likelihood order of markers, cen-(DXYS1X/DXYS13X/DXYS2X/DXYS12X)-DXS366 -DXS178-DXS456-DXS287-DXS358-DXS267- qter, is favored by odds greater than 1000:1 over the subset of most likely alternative orders. Linkage of DXS456 can be inferred for at least six disease genes that are known to be linked to markers in the region Xq21.31-Xq25 and the marker will serve as an important index point for orienting these and other disease and marker loci in the region.

Five polymorphic microsatellite VNTRs on the human X chromosome.

The human genome contains approximately 50,000 copies of an interspersed repeat with the sequence (dT.dG/dA.dC)n, where n = approximately 10-60. We and others have found that several of these repeats have variable lengths in different individuals, with allelic fragments varying in size by multiples of 2 bp. These "microsatellite" variable number of tandem repeats (VNTRs) may be scored by PCR, using unique flanking primers to amplify the repeat-containing regions and resolving the products on DNA sequencing gels. Since few VNTRs have been found on the X chromosome, we screened a flow-sorted X chromosome-specific genomic library for microsatellites. Approximately 25% of the phage clones hybridized to a poly (dT-dG).poly(dA-dC) probe. Of seven X-linked microsatellites present in positive phages, five are polymorphic and three have both eight or more alleles and heterozygosities exceeding 75%. Using PCR to amplify genomic DNAs from hybrid cell panels, we confirmed the X localization of these VNTRs and regionally mapped four of them. The fifth VNTR was regionally mapped by virtue of its tight linkage to DXS87 in Centre du Polymorphisme Humain families. We conclude that whatever factors limit the occurrence of "classical" VNTRs and RFLPs on the X chromosome do not appear to operate in the case of microsatellite VNTRs.

Localization of a human brain sodium channel gene (SCN2A) to chromosome 2.

A DNA probe derived from a human genomic library has been used to localize on human chromosomes a gene coding for the alpha-subunit of the brain type II sodium channel (SCN2A). Hybridization of the probe to Southern blots made with DNAs from a rodent-human somatic cell hybrid panel indicates localization to the long arm of human chromosome 2. In situ hybridization to metaphase chromosomes confirms this assignment and indicates regional localization to 2q21-q33. The probe also reveals a frequent two-allele HaeIII RFLP.

Expression and desensitisation of A2 purinoceptors on cultured bovine aortic endothelial cells.

Purine nucleotides and their metabolites are important mediators of vascular tone. Adenosine promotes relaxation of vascular smooth muscle, acting on the A2 subclass of purinoceptors. There is some evidence that these receptors are also present on vascular endothelial cells. We have therefore examined cultured aortic endothelial cells for adenosine (A2) sensitivity. Bovine aortic endothelial cells (AG4762) were obtained from the Institute of Aging cell repository (USA), and cultured in monolayer flasks. Adenylate cyclase activity in homogenates of AG4762 cells was increased by 5'-(N-ethylcarboxamido)-adenosine (NECA) greater than 2-chloroadenosine greater than adenosine. NECA dependent activation of adenylate cyclase was inhibited by 3-isobutyl-l-methylxanthine greater than theophylline greater than caffeine. The rank order of potency of these compounds identified the responses as mediated by A2 purinoceptors. Prolonged exposure of AG4762 cells to NECA in culture resulted in loss of A2 purinoceptor responsiveness, and purinoceptor activity could be restored to non-dividing densensitized cells by further culture in the absence of the desensitising agent. The cyclic AMP dependent phosphorylation of specific sites in endothelial cells may trigger a number of important biological events which are yet to be determined.

A hypervariable microsatellite revealed by in vitro amplification of a dinucleotide repeat within the cardiac muscle actin gene.

The human genome contains approximately 50,000 copies of an interspersed repeat with the sequence (dT-dG)n, where n = approximately 10-60. In humans, (TG)n repeats have been found in several sequenced regions. Since minisatellite regions with larger repeat elements often display extensive length polymorphisms, we suspected that (TG)n repeats ("microsatellites") might also be polymorphic. Using the polymerase chain reaction to amplify a (TG)n microsatellite in the human cardiac actin gene, we detected 12 different allelic fragments in 37 unrelated individuals, 32 of whom were heterozygous. Codominant Mendelian inheritance of fragments was observed in three families with a total of 24 children. Because of the widespread distribution of (TG)n microsatellites, polymorphisms of this type may be generally abundant and present in regions where minisatellites are rare, making such microsatellite loci very useful for linkage studies in humans.