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Biomedical subjects

A Duffy

Publications and source records attributed to A Duffy.

At least 19 recordsLinked to original sources
PubMed2005

Re-evaluation of randomized control trials of lithium monotherapy: a cohort effect.

OBJECTIVE: The reported reduction of lithium's efficacy in the prophylaxis of bipolar illness has been attributed to various factors, including diagnostic changes and heterogeneous study designs. We attempted to quantify the impact of pre-randomization enrichment designs and diagnostic drift on randomized controlled trials (RCTs) of lithium maintenance therapy. METHODS: Using the Cochrane RCT search filter, MEDLINE, EMBASE, and PSYCHINFO were searched (1966 to June 2004) for all available randomized studies using the text word 'lithium'. Studies of 1 year minimum duration in bipolar disorder involving lithium and placebo arms were identified. Superiority trials without a placebo arm, discontinuation and mirror image studies were excluded. Standardized scales were used to assess randomization and allocation concealment. RESULTS: Nine RCTs enrolling 1432 bipolar I and II patients, randomizing 341 to lithium and 386 to placebo were identified, with 705 reported pre-randomization dropouts. The pooled odds of remaining recurrence free in two non-enriched RCTS using Research Diagnostic Criteria (RDC) or Feighner criteria were 3.2:1 (95% CI 0.65--15.46) trending in favor of lithium over placebo, and 22.0:1 (95% CI 7.0--68.7) for three trials using lithium enrichment and excluding atypical bipolar disorder. The odds of remaining recurrence free using DSM-IV criteria and lamotrigine enrichment were 1.9:1 (95% CI 1.2-2.8). CONCLUSION: Lithium maintenance RCTs differ in patient selection, design, and outcome. A cohort effect can be associated with the use of pre-randomization enrichment phases and, to a lesser extent, with diagnostic drift, compromising straightforward comparisons across three decades of lithium monotherapy in bipolar illness.

Antipsychotic Agents↗
PubMed2001

Heat shock protein 27 inhibits apoptosis in human neutrophils.

BACKGROUND: Prolonged neutrophil(PMN) survival has been implicated in tissue injury following sepsis. A variety of bacterial products have been identified which inhibit PMN apoptosis including lipopolysaccharide(LPS). Extracellular heat shock proteins(Hsp) have recently been identified as potent regulatory signals for the innate immune system during the inflammatory response. We hypothesized that Hsp 27 can affect PMN phenotype with respect to apoptosis and cytokine profile. MATERIALS AND METHODS: PMN were isolated from the peripheral blood of healthy human volunteers by red blood cell sedimentation and gradient centrifugation. Cells were placed in media and cultured for 18 h with and without recombinant human Hsp 27 at various concentrations. In parallel experiments, PMN were stimulated with LPS, a known inhibitor of PMN apoptosis, for comparison. Apoptosis was quantified using annexin V and propidium iodide staining with flow cytometric analysis. Culture supernatants were assayed for secretion of TNF-alpha, IL-10, and IL-12. RESULTS: Hsp 27 significantly inhibits PMN apoptosis [control; 81.8 +/- 3.6%, vs Hsp 27, 60.4 +/- 4.1% p < 0.05]. The reduction is similar to that signaled by LPS, alone. Together their effect is not synergistic. The Hsp 27 response is dose-dependent. Hsp 27 does not induce secretion of TNF-alpha, IL-10, or IL-12, whereas LPS does signal IL-12 and TNF-alpha secretion. CONCLUSION: These data demonstrate that exogenous Hsp 27 may play a role in neutrophil-mediated tissue injury during trauma and sepsis via its ability to inhibit neutrophil apoptosis. However, Hsp 27 does not significantly alter neutrophil phenotype with respect to cytokine production profile.

Apoptosis↗
PubMed2001

Is lithium response related to G(s)alpha levels in transformed lymphoblasts from subjects with bipolar disorder?

BACKGROUND: A series of studies from independent laboratories have found increased levels of G(s)alpha in bipolar disorder in postmortem brain and peripheral blood cells. Long-term lithium administration blunts G-protein coupled cAMP signaling and may regulate G(s)alpha levels. METHODS: We measured G(s)alpha in transformed lymphoblasts obtained from subjects with bipolar disorder and compared the findings with 23 age- and sex-matched controls. To reduce patient heterogeneity, we included only patients with an excellent response to lithium prophylaxis. RESULTS: We found no differences in G(s)alpha protein levels measured with immunoblotting. G(s)alpha levels did not correlate with age, age of onset or duration of lithium therapy. LIMITATIONS: This study made use of transformed lymphoblasts, which may not fully represent changes that occur in regionalized brain tissue. Furthermore, the transformed lymphoblasts used in this study were acquired from a select group of bipolar disorder subjects that responded to lithium treatment. Lastly, consideration has to be given to the small sample size of the study. CONCLUSIONS: These results are consistent with recent observations suggesting that mood state and treatment effects may account at least in part for increased G(s)alpha levels in bipolar disorder. CLINICAL RELEVANCE: This study suggests a need to further characterize biological phenotypes in subjects with mood disorders to enhance genetic studies.

Adult↗
PubMed2001

Measures of attention and hyperactivity symptoms in a high-risk sample of children of bipolar parents.

BACKGROUND: To determine whether significant symptoms of inattention were present among the offspring of well-characterized bipolar parents. METHODS: We included 53 offspring of 30 parents meeting DSM-IV criteria for bipolar disorder diagnosed by consensus on the basis of a SADS-L interview and a wealth of longitudinal clinical data. The unaffected parent had no lifetime history of a major psychiatric illness. Offspring, prospectively followed for up to 5 years, completed psychometric measures of attention and mood when judged to be at a good level of functioning (well, remitted or treated). RESULTS: Those offspring with any lifetime psychiatric diagnosis endorsed more subjective problems with attention. However, there was no measurable difference on tasks of sustained attention between those with and those without a lifetime psychiatric illness including affective disorder. There was a significant association between self-reported symptoms of depression and inattention, but no association between either self-report measure and an objective measure of sustained attention. LIMITATIONS: This study was not intended to be a comprehensive neuropsychological investigation of at risk offspring. CONCLUSIONS: In this high-risk population, subjective difficulty with attention appeared to be state-dependent, associated with the degree of subjective distress related to an underlying psychiatric illness.

Adolescent↗
PubMed2001

Psychiatric diagnoses in the context of genetic studies of bipolar disorder.

Precise definition of the phenotype is an issue of critical importance for the future success of genetic studies of bipolar disorders. So far, an uncertain phenotypic spectrum and genetic heterogeneity are realities that have hampered progress in genetic studies. While recognition of a broader spectrum of related illnesses is important for some applications, for genetic studies a narrow spectrum of illness closely tied to the genotype is paramount. This paper highlights current dilemmas and trends associated with phenotype specification and traces historical approaches. Finally, we explore a number of strategic directions in the diagnostic approach to bipolar disorders that may better serve genetic studies.

Bipolar Disorder↗
PubMed2001

Mapping susceptibility genes for bipolar disorder: a pharmacogenetic approach based on excellent response to lithium.

Genetic mapping studies in bipolar disorder (BD) have been hampered by the unclear boundaries of the phenotypic spectrum, and possibly, by the complexity of the underlying genetic mechanisms, and heterogeneity. Among the suggested approaches to circumvent these problems, a pharmacogenetic strategy has been increasingly proposed. Several studies have indicated that patients with BD who respond well to lithium prophylaxis constitute a biologically distinct subgroup. In this study we have conducted a complete genome scan using 378 markers spaced at an average distance of 10 cM in 31 families ascertained through excellent lithium responders. Response to lithium was evaluated prospectively with an average follow-up of 12 years. Evidence for linkage was found with a locus on chromosome 15q14 (ACTC, lod score = 3.46, locus-specific P-value = 0.000014) and suggestive results were observed for another marker on chromosome 7q11.2 (D7S1816, lod score = 2.68, locus-specific P-value = 0.00011). Other interesting findings were obtained with markers on chromosomes 6 and 22, namely D6S1050 (lod score = 2.0, locus-specific P-value = 0.00004) and D22S420 (lod score = 1.91). Nonparametric linkage analysis provided additional support for the role of these loci. Further analyses of these results suggested that the locus on chromosome 15q14 may be implicated in the etiology of BD, whereas the 7q11.2 locus may be relevant for lithium response. In conclusion, our results provide original evidence suggesting that loci on 15q14 and 7q11.2 may be implicated in the pathogenesis of BD responsive to lithium.

Adult↗
PubMed2000

Anticipation in bipolar affective disorder: is age at onset a valid criterion?

Anticipation has been suggested among the genetic mechanisms of bipolar disorder (BD), prompting the search for unstable DNA sequences. Past studies of anticipation in BD have generally relied on observed shift in the age at onset between parental and offspring generations. Such a shift, however, may be caused by a number of other factors difficult to correct for. We investigated age at onset distributions in a sample of 161 related subjects and in a sample of "pseudofamilies" consisting of 320 unrelated subjects selected from a large epidemiological cohort using Monte-Carlo simulation to mimic the family sample. Comparison of age at onset distributions in both samples shows a difference between the generations, but of a similar magnitude in each sample. This suggests that age at onset alone may not be a sufficient criterion of anticipation. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:804-807, 2000.

Adult↗
PubMed2000

Association and linkage studies of CRH and PENK genes in bipolar disorder: a collaborative IGSLI study.

Corticotropin-releasing hormone (CRH) and proenkephalin (PENK) are hypothalamic peptides involved in the stress response and hypothalamic-pituitary axis regulation. Previous research has implicated these peptides in the pathogenesis of affective disorders. In this study we investigated two polymorphisms located in the genes that code for CRH and PENK by means of association and linkage analyses. A total of 138 bipolar patients and 108 controls were included in the association study. In addition, 24 families were available for linkage analysis, including six families of probands with documented periodic positivity of dexamethasone suppression tests (DST) during remission. We found no association of bipolar disorder with either gene. Similarly, we did not find any evidence of linkage (P = 0.56 for CRH and 0.52 for PENK) in the entire sample or in the subsample of families of DST positive probands. In conclusion, our study does not support the hypothesis that genes coding for CRH or PENK contribute to the genetic susceptibility to bipolar disorder. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:178-181, 2000.

Adult↗
PubMed2000

Polyglutamine coding genes in bipolar disorder: lack of association with selected candidate loci.

BACKGROUND: Several studies have suggested that expanded trinucleotide repeats, particularly CAG, may have a role in the etiology of BD. Results obtained with the repeat expansion detection technique (RED) have indicated that bipolar patients have an excess of expanded CAG repeats. However, it is not clear which loci account for this difference. METHODS: Using lithium-responsive bipolar patients in order to reduce heterogeneity, we investigated five loci that are expressed in the brain and contain translated CAG repeats. A sample of 138 cases and 108 controls was studied. Genotypes were coded quantitatively or qualitatively and repeat distributions were compared. RESULTS: No difference was found in allele distribution between cases and controls for any of the loci studied. In one locus - L10378 - patients had a tendency to present shorter alleles (28.1 versus 27.9 repeats; t=2.55, df=205, P=0.011), however, this difference disappeared after correction for multiple testing. LIMITATIONS: The study has limitations common to most candidate gene association studies, that is, limited number of loci investigated and limited power to detect loci that account for a small proportion of the total genetic variability. CONCLUSIONS: Our results suggest that the loci investigated have no major role in the genetic predisposition to bipolar disorder.

Adult↗
PubMed2000

Inhibition of neutrophil apoptosis after severe trauma is NFkappabeta dependent.

BACKGROUND: Systemic inflammation may inhibit neutrophil (PMN) apoptosis and promote multiple organ dysfunction syndrome. We hypothesize that severe trauma causes dysregulation of PMN apoptosis. METHODS: Neutrophils were isolated from trauma patients (24-72 hours after injury; n = 16) and controls (healthy volunteers) and incubated for 18 hours. In separate experiments, control cells were treated +/- the nuclear factor kappa beta (NFkappabeta) inhibitor pyrrolidinithiocarbamate then incubated with 25% patient or control plasma. Apoptosis was quantified by enzyme-linked immunosorbent assay for histone-associated DNA and annexin V fluorescence-activated cell sorter. NFkappabeta activation was determined by Western blot for phosphorylated I kappabeta. RESULTS: Apoptosis was inhibited in trauma patient PMN. Neutrophil apoptosis correlated with multiple organ dysfunction syndrome score, Acute Physiology and Chronic Health Evaluation II, and platelet count. Patient plasma inhibited apoptosis and induced phosphorylation of I kappabeta in control cells. Inhibition of PMN apoptosis by patient plasma was blocked by pretreatment with pyrrolidinithiocarbamate. CONCLUSION: NFkappabeta-dependent inhibition of neutrophil apoptosis occurs after trauma. Early inhibition of PMN apoptosis is dependent on the magnitude of injury.

Apoptosis↗
PubMed2000

Inhibited neutrophil apoptosis: proteasome dependent NF-kappaB translocation is required for TRAF-1 synthesis.

Neutrophil (PMN) apoptosis regulates local and systemic inflammation during sepsis. Tumor necrosis factor receptor-associated factors (TRAFs) have been implicated as mediators of apoptosis; however, the signaling pathways for their production in stimulated PMN are unclear. We hypothesize that NF-kappaB translocation is necessary for the induction of TRAF-1 in PMNs with prolonged survival. Neutrophils were isolated from the blood of healthy volunteers by Ficoll gradient centrifugation and red blood cell sedimentation. Neutrophil NF-kappaB was inhibited with a proteasome inhibitor, PSI-I. Cells were treated with PSI-I (30 microM) or vehicle (DMSO 0.2%) for 50 min then incubated over an 18-h time course with LPS (10 to 1000 ng/mL), tumor necrosis factor alpha (TNFalpha) (2 to 20 ng/mL) or control media. In vitro apoptosis was quantified by propidium iodide FACS analysis. Total cellular TRAF-1 was detected by Western blot analysis of cell lysates. Steady state TRAF-1 mRNA was detected by RPA. NF-kappaB activity was determined by Western blot analysis for nuclear p65. Means and standard errors were calculated; data were analyzed by ANOVA. Lipopolysaccharide (LPS) and TNFalpha increased PMN nuclear p65 and steady state TRAF-1 mRNA. Apoptosis was inhibited by TNFalpha and LPS at 12 and 18 h (P < 0.01). Incubation of cells in the NF-kappaB inhibitor PSI-I blocked LPS and TNFalpha-induced inhibition of apoptosis (P < 0.05) and the induction of both nuclear p65 and TRAF-1 mRNA. These data demonstrate that inhibition of PMN apoptosis and TRAF-1 induction by LPS and TNFalpha is NF-kappaB dependent.

Apoptosis↗
PubMed2000

Activated neutrophils induce nitric oxide production in Kupffer cells.

Neutrophils (PMN) are proposed to contribute to hepatic dysfunction during sepsis. Transmigrating PMN have been demonstrated to adhere to and injure parenchymal cells (hepatocytes); however, the effect of sepsis-activated PMN on hepatic macrophages or Kupffer cells (KC) is poorly characterized. We hypothesize that PMN influence KC inflammatory mediator production, including nitric oxide. Rodent KC were co-cultured with PMN obtained from controls (Norm-PMN) or endotoxemic rats [lipopolysaccharide (LPS)-PMN] for 18 h. After an 18-h incubation, supernatants and cell lysates of the KC were analyzed for nitric oxide (NO) production. Co-cultures with LPS-PMN/KC demonstrated significantly increased production of nitrite and up-regulation of inducible nitric oxide synthase (iNOS) protein compared to KC alone or Norm-PMN/KC co-cultures. Immunohistochemistry revealed preferential iNOS protein staining in the cytoplasm of KC cultured with LPS-PMN compared to controls. Nitrite production in co-cultures of KC and LPS-PMN where cell contact was inhibited by a cell impermeable but diffusable membrane was significantly reduced. These data provide evidence that KC can be stimulated directly by activated PMN for production of NO. Further, they suggest another mechanism by which PMN modulate hepatic function during sepsis.

Animals↗
PubMed2000

Toward effective early intervention and prevention strategies for major affective disorders: a review of antecedents and risk factors.

OBJECTIVE: To review critically the literature pertaining to risk factors and antecedent symptoms and syndromes in order to determine an empirically based strategy for early treatment and prevention of major mood episodes. METHOD: The relevant literature is summarized, with particular emphasis on early-onset (child and adolescent) mood disorders. RESULTS: A complex interaction between biological, psychological, and sociological factors contributes to the development of a major mood disorder. Having a positive family history of mood disorder (bipolar and unipolar) and being female (unipolar) are the strongest, most reliable risk factors. There is continuity between adolescent and adult mood disorders, and subsyndromal mood disturbance in adolescents has clinical and public health significance. However, more longitudinal study is required to reliably map the course and predictive importance of mood disorders in very young children. CONCLUSIONS: Substantial evidence supports the effectiveness of early intervention and prevention efforts in children at risk for mood disorders (identified as having affected family members) and in adolescents manifesting significant mood symptoms and syndromes (especially if associated with a positive family history). However, the current level of understanding regarding the etiological significance and mechanism of risk factors associated with mood disorders does not support broad community-based primary prevention strategies in unselected populations.

Adult↗
PubMed2000

The implications of genetics studies of major mood disorders for clinical practice.

BACKGROUND: This article is a selective review and synthesis of relevant research findings from genetic studies of major mood disorders and the application of these to clinical practice. METHOD: The article discusses the application of genetic research findings in major mood disorders, including epidemiologic and family study risk estimates, risk modifiers, and the concepts of etiologic and phenotypic heterogeneity, to 3 clinical domains: risk counseling, diagnosis, and treatment prediction. RESULTS: Epidemiologic and family studies have provided general risk estimates useful in counseling mood-disordered patients and their relatives. A complete and accurate family pedigree provides more individualized risk estimates for specific cases and is useful in identifying the phenotypic spectrum of the disorder being transmitted in the family. Both proband course parameters and familial loading for psychiatric illnesses may be relevant for the prediction of treatment response. However, the hypothesis of inherited pharmacologic selectivity remains to be proven. CONCLUSION: Genetic studies of mood disorders have not yet provided conclusive evidence of specific susceptibility genes or their pattern of inheritance. However, they have generated information that is useful to clinical practice.

Adult↗
PubMed2000

Association and linkage studies of candidate genes involved in GABAergic neurotransmission in lithium-responsive bipolar disorder.

OBJECTIVE: To test for genetic linkage and association with GABAergic candidate genes in lithium-responsive bipolar disorder. DESIGN: Polymorphisms located in genes that code for GABRA3, GABRA5 and GABRB3 subunits of the GABAA receptor were investigated using association and linkage strategies. PARTICIPANTS: A total of 138 patients with bipolar 1 disorder with a clear response to lithium prophylaxis, selected from specialized lithium clinics in Canada and Europe that are part of the International Group for the Study of Lithium-Treated Patients, and 108 psychiatrically healthy controls. Families of 24 probands were suitable for linkage analysis. OUTCOME MEASURES: The association between the candidate genes and patients with bipolar disorder versus that of controls and genetic linkage within families. RESULTS: There was no significant association or linkage found between lithium-responsive bipolar disorder and the GABAergic candidate genes investigated. CONCLUSIONS: This study does not support a major role for the GABAergic candidate genes tested in lithium-responsive bipolar disorder.

Alleles↗
PubMed1999

Lithium responsive bipolar disorder, unilineality, and chromosome 18: A linkage study.

Over the last three years several studies have investigated the hypothesis of linkage between bipolar disorder and markers on chromosome 18. Although independent groups have reported positive results, it is still not clear how these should be interpreted, as linkage spans a considerably large segment of the chromosome. In this study we have investigated linkage with chromosome 18 markers in 19 families of lithium-responsive bipolar patients, as a way to select a more homogeneous population. In addition, we have investigated whether there is evidence of a parent-of-origin effect as suggested by previous studies. Eleven markers spanning the whole chromosome were typed and linkage analysis was carried out using parametric and nonparametric methods. Analysis of the whole sample provided nonsignificant linkage results. However, when the sample included only unilineal families, and was further stratified according to parental origin, two chromosomal regions provided modestly positive lod scores. Maximum lod scores of 1.04 (P = 0.001) at D18S53 and 0.87 (P = 0.045) at D18S61 were observed for maternal and paternal pedigrees, respectively. Nonparametric analysis yielded similar results. In conclusion, our results are congruent with previous reports that suggest an advantage of unilineal pedigrees in linkage analysis of bipolar disorder and cannot rule out a parent-of-origin effect in this genomic region.

Adolescent↗