The authors previously demonstrated significant association between markers within NOS1AP and schizophrenia in a set of Canadian families of European descent, as well as significantly increased expression in schizophrenia of NOS1AP in unrelated postmortem samples from the dorsolateral prefrontal cortex. In this study the authors sought to apply novel statistical methods and conduct additional biological experiments to isolate at least one risk allele within NOS1AP.
Using the posterior probability of linkage disequilibrium (PPLD) to measure the probability that a single nucleotide polymorphism (SNP) is in linkage disequilibrium with schizophrenia, the authors evaluated 60 SNPs from NOS1AP in 24 Canadian families demonstrating linkage and association to this region. SNPs exhibiting strong evidence of linkage disequilibrium were tested for regulatory function by luciferase reporter assay. Two human neural cell lines (SK-N-MC and PFSK-1) were transfected with a vector containing each allelic variant of the SNP, the NOS1AP promoter, and a luciferase gene. Alleles altering expression were further assessed for binding of nuclear proteins by electrophoretic mobility shift assay.
Three SNPs produced PPLDs >40%. One of them, rs12742393, demonstrated significant allelic expression differences in both cell lines tested. The allelic variation at this SNP altered the affinity of nuclear protein binding to this region of DNA.
The A allele of rs12742393 appears to be a risk allele associated with schizophrenia that acts by enhancing transcription factor binding and increasing gene expression.
PMID: 19255043 CAMSID: cams2101
The authors report on the use of the DSM-III, several years after its introduction, in the clinical diagnosis of 154 subjects with first onset psychosis. Clinicians usually assigned Axis I diagnoses but used the remainder of the multiaxial system less than one time in three; if a standard recording form was in place, the multiaxial system was used more often. Trainees used the DSM-III most, followed by psychiatrists affiliated with a university and community based clinicians. Agreement between researchers and clinicians on diagnoses was fair to poor. The authors discuss the implications of the acceptance of the complex diagnostic system in routine clinical practice.
PMID: 1868420 CAMSID: cams1957
It remains unclear whether age at onset for major psychiatric disorders is a useful marker of etiologic and genetic heterogeneity. The authors examined how heritability of schizophrenia and major affective disorders varied with age at onset. The sample was drawn from a large archival data set collected by Lionel Penrose, comprising 3,109 families with two or more members first hospitalized in Ontario between 1874 and 1944. The authors studied 1,295 sibships with schizophrenia (n = 487), major affective disorder (n = 378), both (n = 234) or neither (n = 196) of these disorders. Proportional hazards models were used to estimate how the hazard of hospitalization for each disorder (schizophrenia or major affective disorder) varied with proband age at onset, adjusted for changes in age at onset distribution between 1874 and 1944. A sibling’s risk of hospitalization for the same illness significantly increased for each 10-year decrease in age at onset of the proband both for schizophrenia (hazard ratio = 1.21, 95 % confidence interval: 1.06, 1.39), and for affective disorder (hazard ratio = 1.29, 95 % CI: 1.14,1.45). Gender of proband was unrelated to sibling risk of the same illness, and tests of interaction effects between proband age at onset and gender on sibling risk were nonsignificant.
PMID: 16331352 CAMSID: cams1793
age of onset; cohort effect; mood disorders; schizophrenia; heredity
From the individual perspective of the two authors who were long-time colleagues of Karl Lederis at the University of Calgary, the events and personal interactions are described, that are relevant to the discovery of Urotensin I (UI) in the Lederis laboratory, along with the concurrent discovery of Urotensin II (UII) in the Bern laboratory and corticotropin-releasing factor (CRF/CRH) in the Vale laboratory. The fortuitous sabbatical experiences that put Professors Lederis and Bern on the track of the Urotensins, along with the essential isolation paradigm that resulted in the complete sequencing and synthesis of UI and UII are summarized. The chance interaction between Drs. Vale and Lederis who, prior to the publications of the sequences of UI and CRF, realized the sequence commonalities of these peptides with the vasoactive frog peptide, sauvagine, is outlined. Further, the relationship between the pharmacological studies done with UI in the Calgary laboratory and the more recent understanding of the biology and receptor pharmacology for the entire Urotensin I–CRF–Urocortin peptide family is dealt with. The value of a comparative endocrinology approach to understanding hormone action is emphasized, along with a projection to the future, based on new hypotheses that can be generated by unexplained data already in the literature. Based on the previously described pharmacology of the UI–CRF–Urocortin peptides in a number of target tissues, it is suggested that the use of current molecular approaches can be integrated with a ‘classical’ pharmacological approach to generate new insights about the UI–CRF–Urocortin hormone family.
PMID: 19409389 CAMSID: cams2629
Corticotropin-releasing factor (CRF); CRF1; CRF2; Oxytocin; Urocortin; Urophysis; Urotensin; Vasopressin; Fish; Teleosts
Following proximal peripheral nerve injury, motor recovery is often poor due to prolonged muscle denervation and loss of regenerative potential. The transfer of a sensory nerve to denervated muscle results in improved functional recovery in experimental models. The authors here report the first clinical case of sensory protection. Following a total hip arthroplasty, this patient experienced a complete sciatic nerve palsy with no recovery at 3 months postsurgery and profound denervation confirmed electrodiagnostically. He underwent simultaneous neurolysis of the sciatic nerve and saphenous nerve transfers to the tibialis anterior branch of the peroneal nerve and gastrocnemius branch from the tibial nerve. He noted an early proprioceptive response. Electromyography demonstrated initially selective amelioration of denervation potentials followed by improved motor recovery in sensory protected muscles only. The patient reported clinically significant functional improvements in activities of daily living. The authors hypothesize that the presence of a sensory nerve during muscle denervation can improve functional motor recovery.
PMID: 18976091 CAMSID: cams2284
muscle denervation; sciatic nerve palsy; sensory nerve
To assess whether age-related differences in suppressing nontarget material impact subsequent performance, the authors initially asked younger and older adults to perform a go/nogo task with colored letters used as conflicting go/nogo stimuli and 2 colored numbers as low-conflict nogo stimuli. Next, participants performed another go/nogo task. A previous number was reused as a nogo stimulus and the other as a go stimulus, with new numbers serving as a baseline. In a 1st block of trials, younger adults showed slower responses to previous nogo/now-go numbers than to new go numbers, an effect not shown by older adults. Alternative accounts of these differential transfer costs are discussed.
PMID: 20718536 CAMSID: cams2238
normal aging; suppression; transfer cost; cognitive interference; go/nogo
Researchers are increasingly using observational or nonrandomized data to estimate causal treatment effects. Essential to the production of high-quality evidence is the ability to reduce or minimize the confounding that frequently occurs in observational studies. When using the potential outcome framework to define causal treatment effects, one requires the potential outcome under each possible treatment. However, only the outcome under the actual treatment received is observed, whereas the potential outcomes under the other treatments are considered missing data. Some authors have proposed that parametric regression models be used to estimate potential outcomes. In this study, we examined the use of ensemble-based methods (bagged regression trees, random forests, and boosted regression trees) to directly estimate average treatment effects by imputing potential outcomes. We used an extensive series of Monte Carlo simulations to estimate bias, variance, and mean squared error of treatment effects estimated using different ensemble methods. For comparative purposes, we compared the performance of these methods with inverse probability of treatment weighting using the propensity score when logistic regression or ensemble methods were used to estimate the propensity score. Using boosted regression trees of depth 3 or 4 to impute potential outcomes tended to result in estimates with bias equivalent to that of the best performing methods. Using an empirical case study, we compared inferences on the effect of in-hospital smoking cessation counseling on subsequent mortality in patients hospitalized with an acute myocardial infarction.
PMID: 22419832 CAMSID: cams2143
Structural variations of DNA, such as copy number variations (CNVs), are recognized to contribute both to normal genomic variability and to risk for human diseases. For example, schizophrenia has an established connection with 22q11.2 deletions. Recent genome-wide studies have provided initial evidence that CNVs at other loci may also be associated with schizophrenia. In this article, the authors provide a brief overview of CNVs, review recent findings related to schizophrenia, outline implications for clinical practice and diagnostic subtyping, and make recommendations for future reports on CNVs to improve interpretation of results.
The review included genome-wide surveys of CNVs in schizophrenia that included one or more comparison groups, were published before 2009, and used newer methods. Six studies were identified.
Despite some limitations, these initial genome-wide studies of CNVs provide replicated associations of schizophrenia with rare 1q21.1 and 15q13.3 deletions. Collectively, the results point to a more general mutational mechanism involving rare CNVs that elevate risk for schizophrenia, especially more developmental forms of the disease. Including 22q11.2 deletions, rare risk-associated CNVs appear to account for up to 2% of schizophrenia.
The more penetrant CNVs have direct implications for clinical practice and diagnostic subtyping. CNVs with lower penetrance promise to contribute to our genetic understanding of pathogenesis. The findings provide insight into a broader neuropsychiatric spectrum for schizophrenia than previously conceived and indicate new directions for genetic studies.
PMID: 20439386 CAMSID: cams2100
Histories of violence and of hyperactivity are both characterized by poor cognitive–neuropsychological function. However, researchers do not know whether these histories combine in additive or interactive ways. The authors tested 303 male young adults from a community sample whose trajectories of teacher-rated physical aggression and motoric hyperactivity from kindergarten to age 15 were well defined. No significant interaction was found. In a 1st model, both histories of problem behavior were independently associated with cognitive–neuropsychological function in most domains. In a 2nd model controlling for IQ, general memory, and test motivation, the 3 working-memory tests (relevant to executive function) remained associated with physical aggression, and 1 remained associated with hyperactivity. These results support an additive model.
PMID: 15535792 CAMSID: cams2127
Individuals with 22q11.2 deletion syndrome are known to be at high risk of developing schizophrenia. Previous imaging studies have provided limited data on the relation of schizophrenia expression in 22q11.2 deletion syndrome to specific regional brain volumetric changes. The authors hypothesized that the main structural brain finding associated with schizophrenia expression in 22q11.2 deletion syndrome, as for schizophrenia in the general population, would be gray matter volumetric deficits, especially in the temporal lobes.
MR brain images from 29 patients with 22q11.2 deletion syndrome and schizophrenia and 34 comparison subjects with 22q11.2 deletion syndrome and no history of psychosis were analyzed using a voxel-based morphometry method that also yielded volumes for related region-of-interest analyses. The authors compared data from the two groups using an analysis of covariance model correcting for total intracranial volume, age, sex, IQ, and history of congenital cardiac defects. The false discovery rate threshold was set at 0.05 to account for multiple comparisons.
Voxel-based morphometry analyses identified significant gray matter reductions in the left superior temporal gyrus (Brodmann’s area 22) in the schizophrenia group. There were no significant between-group differences in white matter or CSF volumes. Region-of-interest analyses showed significant bilateral gray matter volume reductions in the temporal lobes and superior temporal gyri in the schizophrenia group.
The structural brain expression of schizophrenia associated with the highly penetrant 22q11.2 deletion involves lower gray matter volumes in temporal lobe regions. These structural MRI findings in a 22q11.2 deletion syndrome form of schizophrenia are consistent with those from studies involving schizophrenia samples from the general population. The results provide further support for 22q11.2 deletion syndrome as a genetic subtype and as a useful neurodevelopmental model of schizophrenia.
PMID: 21362743 CAMSID: cams2144
In this systematic review we evaluated the effectiveness of emergency department (ED)-based management interventions for mental health presentations with an aim to provide recommendations for pediatric care.
A search of electronic databases, references, key journals and conference proceedings was conducted and primary authors contacted. Experimental and observational studies that evaluated ED crisis care with pediatric and adult patients were included. Adult-based studies were evaluated for potential translation to pediatric investigation. Pharmacological-based studies were excluded. Inclusion screening, study selection, and methodological quality were assessed by two independent reviewers. One reviewer extracted the data and a second checked for completeness and accuracy. Presentation of study outcomes included odds ratios (OR) and mean differences (MD) with 95% confidence intervals (CI). Meta-analysis was deferred due to clinical heterogeneity in intervention, patient population, and outcome.
Twelve observational studies were included in the review with pediatric (n=3), and adult or unknown (n=9) aged participants. Pediatric studies supported the use of specialized care models to reduce hospitalization (OR=0.45; 95%CI:0.33,0.60), return ED visits (OR=0.60, 95%CI:0.28,1.25), and length of ED stay (MD=−43.1min; 95%CI:−63.088,−23.11). In an adult study, reduced hospitalization was reported in a comparison of a crisis intervention team to standard care (OR=0.59; 95%CI:0.43,0.82). Five adult-based studies assessed triage scales; however, little overlap in the scales investigated and the outcomes measured limited comparability and generalizability for pediatrics. In a comparison of a mental health scale to a national standard, one study demonstrated reduced ED wait (MD=−7.7 min; 95%CI:−12.82,−2.58) and transit (MD=−17.5 min; 95%CI:−33.00,−1.20) times. Several studies reported a shift in triage scores of psychiatric patients dependent on the scale or nurse training (psychiatric vs. emergency), but linkage to system- or patient-based outcomes was not made limiting clinical interpretation.
Pediatric studies have demonstrated that the use of specialized care models for mental health care can reduce hospitalization, return ED visits, and length of ED stay. Evaluation of these models using more rigorous study designs and the inclusion of patient-based outcomes will improve this evidence base. Adult-based studies provided recommendations for pediatric research including a focus on triage and restraint use.
PMID: 21131813 CAMSID: cams1631
mental health services; crisis; emergency care
Both depression and smoking are highly prevalent and related to poorer outcomes in cardiac patients. In this study, the authors examined the association between depressive symptoms and smoking status, described the frequency and type of antidepressant use, and prospectively tested the effects of antidepressant use in smokers on smoking status and psychosocial outcomes. Participants comprised 1498 coronary artery disease (CAD) outpatients who completed a baseline survey which assessed depressive symptoms, current medications, and smoking status. A second survey was mailed 9 months later that assessed depressive symptoms, anxiety, insomnia, current medications and smoking status. Results showed that current and former-smokers had significantly greater depressive symptoms than non-smokers. Ten percent of patients were taking antidepressants, most frequently SSRIs, with significantly more smokers on antidepressants than former and non-smokers. At follow-up, smokers on antidepressants were less likely to have quit, had greater anxiety, depressive symptoms and insomnia than smokers not using antidepressants. This study demonstrated that smokers and quitters with CAD had greater depressive symptoms and use of antidepressants than non-smokers, but that the antidepressants utilized may not be optimizing outcomes.
PMID: 19504177 CAMSID: cams1434
Smoking; Depression; Antidepressants; Coronary artery disease (CAD); Outpatients
This systematic review evaluated the effectiveness of professional and organizational interventions aimed at improving medical processes, such as documentation or clinical assessments by health care providers, in the care of pediatric emergency department (ED) patients where abuse was suspected.
A search of electronic databases, references, key journals/conference proceedings was conducted and primary authors contacted. Studies whose purpose was to evaluate a strategy aimed at improving ED clinical care of suspected abuse were included. Study methodological quality was assessed by two independent reviewers. One reviewer extracted the data and a second checked for completeness and accuracy.
Six studies met the inclusion criteria: one randomized (RCT) and one quasi-randomized trial (qRCT), and four observational studies. Study quality ranged from modest (observational studies) to good (trials). Variation in study interventions and outcomes limited between study comparisons. One qRCT supported self-instructional education kits as a means to improve physician knowledge for both physical abuse (mean pre-test score: 13.12, SD 2.36; mean post-test score: 18.16, SD 1.64) and sexual abuse (mean pre-test score: 10.81, SD 3.20; mean post-test score: 18.45, SD 1.79). Modest quality observational studies evaluated reminder systems for physician documentation with similar results across studies. Compared to standard practice, chart checklists paired with an educational program increased physician consideration of non-accidental burns in burn cases (59% increase), documentation of time of injury (36% increase), as well as documentation of consistency (53% increase) and compatibility (55% increase) of reported histories. Decisional flowcharts for suspected physical abuse also increased documentation of non-accidental physical injury (69.5% increase; p<0.0001) and had a similar significant impact as checklists on increasing documentation of history consistency and compatibility (69.5% and 70.0% increases, respectively; p<0.0001) when compared to standard practice. No improvements were noted in these studies for documentation of consultations or current status with child protective services. The introduction of a specialized team and crisis center to standardize practice had little effect on physician documentation, but did increase documentation of child protective services involvement (22.7% increase; p<0.005) and discharge status (23.7% increase; p<0.02). Referral to social services increased in one study following the introduction of a chart checklist (8.6% increase; p=0.018). A recently conducted multi-site RCT did not support observational findings, reporting no significant effect of educational sessions and/or a chart checklist on ED practices.
The small number of studies identified in this review highlights the need for future studies that address care of a vulnerable clinical population. While moderate quality observational studies suggested education and reminder systems increased clinical knowledge and documentation, these findings were not supported by a single randomized trial. The limited theoretical base for conceptualizing change in health care providers and the influence of the ED environment on clinical practice are limitations to this current evidence base.
PMID: 20370740 CAMSID: cams1630
The lamin B2 locus is the only mammalian origin whose replication initiation points (RIPs) have been mapped. Although this paper was published 8 years ago, no further mammalian RIP-mapping studies have been reported, largely due to technical difficulties of ligation-mediated (LM)-PCR used by the authors. Here, we report the development of a simple, one-way PCR-based protocol that allows one to accurately determine RIPs at mammalian origins. The procedure can be completed within 48 h from the time of cell lysis in the agarose gel. Nascent DNA is then isolated from the same gel after DNA is separated by alkaline gel electrophoresis. Subsequently, RIPs are determined by one-way PCR-based primer extension using labeled primers. Using this protocol, we have successfully mapped RIPs in the human DBF4 locus. As one-way PCR is routinely used by many scientists, this protocol will provide a powerful new tool for studying DNA replication in many organisms including mammalian cells.
PMID: 18927558 CAMSID: cams351
The authors examined whether the supply of primary care physicians had protective effects on breast cancer stage and survival in Ontario and whether supply losses during the 1990s were associated with diminished protection.
Random samples of the Ontario Cancer Registry, respectively, provided 879 women and 951 women who were diagnosed with breast cancer between 1988 and 1990 (followed until 1996) and 1998 and 2000 (followed until 2006), respectively. Active physician supply data (1991 and 2001) joined to each woman’s census division of residence was taken from the Scott’s Medical Database.
Protective thresholds were observed among the earlier cohort for supplies of general practitioners (7 per 10,000 population) and supplies of obstetricians/gynecologists (6 per 100,000 population) at or above which women with breast cancer were significantly more likely to have been diagnosed with localized disease and to have survived for ≥5 years. These protective effects seemed generally attenuated among the more recent cohort. The risk of living in primary care physician-undersupplied areas increased significantly between 1991 and 2001 (10%–30%), and such physician supply losses were associated with reduced cancer care protection, including less prevalent early diagnoses (odds ratio [OR], 1.60; 95% confidence interval [95% CI], 1.00–2.58) and lower 5-year survival rates (OR, 1.62; 95% CI, 1.03–2.55).
Primary care physician supplies appeared to matter very much in the effective provision of cancer care in Canada. Community healthcare service endowments that include adequate physician supplies may be particularly critical to the performance of a healthcare system such as that in Canada, which provides universal accessibility to medically necessary care.
PMID: 19484796 CAMSID: cams1397
physician supplies; primary care; general practitioners; family physicians; obstetrician/gynecologists; healthcare service endowments; breast cancer; stage at diagnosis; survival; Ontario; Canada
The authors identified a missense mutation in the FTL gene (474G>A; A96T) in a 19-year-old man with parkinsonism, ataxia, corticospinal signs, mild nonprogressive cognitive deficit, and episodic psychosis. This mutation was also present in his asymptomatic mother and younger brother, who had abnormally low levels of ferritin in the serum. The patient and his mother displayed bilateral involvement of the pallidum.
PMID: 16116125 CAMSID: cams1060
Reproduction is at the core of many aspects of human existence. It is intrinsic in our biology and in the broad social constructs in which we all reside. The introduction to this special issue is designed to reflect on some of the differences between the humanities/arts and the sciences on the subject of Reproduction now and in the past. The intellectual/cultural distance between humanists and reproductive biologists is vast, yet communication between the Two Cultures has much to offer in guiding future research, pedagogy, and social policy. The challenges to communication include differences in methodology, professional protocols, specialization, and the increasing speed with which reproductive technology advances. The solutions require a new kind of student who can learn and adapt the approaches from both sides of the disciplinary divide to create new ways of understanding how our current and future concepts of reproduction may be informed by the past. This co-authored introduction reviews the range of interests represented in the essays and represents first steps of a dialogue between a humanist and a reproductive biologist who chart some of the possibilities on what the future of the subject might hold.
PMID: 19937463 CAMSID: cams562
Reproduction; Humanities; Science; History; Imaging; Transdisciplinarity
Previous work has shown that older adults encode lexical and semantic information about verbal distractors and use that information to facilitate performance on subsequent tasks. In this study, we investigated whether older adults also form associations between distractors and co-occurring targets. In two experiments, participants performed a 1-back task on pictures superimposed with irrelevant words; 10 min later, participants were given a paired-associates memory task without reference to the 1-back task. The study list included preserved and re-paired (disrupted) pairs from the 1-back task. Older adults showed a memory advantage for preserved pairs and a disadvantage for disrupted pairs, whereas younger adults performed similarly across pair types. These results suggest the existence of a hyper-binding phenomenon in which older adults encode seemingly extraneous co-occurrences in the environment and transfer this knowledge to subsequent tasks. This increased knowledge of how events covary may be the reason why real-world decision-making ability is retained, or even enhanced, with age.
PMID: 20424077 CAMSID: cams2236
inhibition; attention; associative memory; aging; binding
Redox enzyme substrates of the twin-arginine translocation (Tat) system contain a RR-motif in their leader peptide and require the assistance of chaperones, redox enzyme maturation proteins (REMPs). Here various regions of the RR-containing oxidoreductase subunit (leader peptide, full preprotein with and without a leader cleavage site, mature protein) were assayed for interaction with their REMPs. All REMPs bound their preprotein substrates independent of the cleavage site. Some showed binding to either the leader or mature region, whereas in one case only the preprotein bound its REMP. The absence of Tat also influenced the amount of chaperone–substrate interaction.
MINT-8047497: FdhE (uniprotkb:P13024) and FdoG (uniprotkb:P32176) physically interact (MI:0915) by two hybrid (MI:0018)
MINT-8046441: HybO (uniprotkb:P69741) and HybE (uniprotkb:P0AAN1) physically interact (MI:0915) by two hybrid (MI:0018)
MINT-8046375: DmsA (uniprotkb:P18775) and DmsD (uniprotkb:P69853) physically interact (MI:0915) by two hybrid (MI:0018)
MINT-8046425: TorA (uniprotkb:P33225) and TorD (uniprotkb:P36662) physically interact (MI:0915) by two hybrid (MI:0018)
MINT-8046393: NarJ (uniprotkb:P0AF26) and NarG (uniprotkb:P09152) physically interact (MI:0915) by two hybrid (MI:0018)
MINT-8046409: NapD (uniprotkb:P0A9I5) and NapA (uniprotkb:P33937) physically interact (MI:0915) by two hybrid (MI:0018)
PMID: 20974141 CAMSID: cams1627
System specific chaperone; Twin-arginine translocase system; Twin arginine translocase; Leader sequence; Bacterial two-hybrid; Protein maturation
The labyrinth of the rodent placenta contains villi that are the site of nutrient exchange between mother and fetus. They are covered by three trophoblast cell types that separate the maternal blood sinusoids from fetal capillaries – a single mononuclear cell that is a subtype of trophoblast giant cell (sinusoidal or S-TGC) with endocrine function and two multinucleated syncytiotrophoblast layers, each resulting from cell-cell fusion, that function in nutrient transport. The developmental origins of these cell types have not previously been elucidated. We report here the discovery of cell-layer-restricted genes in the mid-gestation labyrinth (E12.5-14.5) including Ctsq in S-TGCs (also Hand1-positive), Syna in syncytiotrophoblast layer I (SynT-I), and Gcm1, Cebpa and Synb in syncytiotrophoblast layer II (SynT-II). These genes were also expressed in distinct layers in the chorion as early as E8.5, prior to villous formation. Specifically, Hand1 was expressed in apical cells lining maternal blood spaces (Ctsq is not expressed until E12.5), Syna in a layer immediately below, and Gcm1, Cebpa and Synb in basal cells in contact with the allantois. Cebpa and Synb were co-expressed with Gcm1 and were reduced in Gcm1 mutants. By contrast, Hand1 and Syna expression was unaltered in Gcm1 mutants, suggesting that Gcm1-positive cells are not required for the induction of the other chorion layers. These data indicate that the three differentiated trophoblast cell types in the labyrinth arise from distinct and autonomous precursors in the chorion that are patterned before morphogenesis begins.
PMID: 18448564 CAMSID: cams1845
Chorion; Gcm1; Labyrinth; Placenta; Syncytin; Syncytiotrophoblast; Trophoblast; Mouse
Uncoupling proteins (UCPs) are modulators of mitochondrial metabolism that have been implicated in the development of both insulin resistance and insulin insufficiency, the two major pathophysiological events associated with type 2 diabetes. UCP2 mRNA is expressed in a wide range of tissues; however UCP2 protein expression is restricted to fewer tissues, including the endocrine pancreas, spleen, stomach, brain and the lung. To date, its role in the pathophysiology of diabetes has been most strongly associated with impaired glucose-stimulated insulin secretion from the β-cell, particularly after its induction by free fatty acids. The physiological role of UCP2 remains controversial, but it may act as a downstream signal transducer of superoxide. UCP3 mRNA and protein are expressed in relatively few tissues, predominately skeletal muscle, brown adipose tissue and heart. Increased expression of UCP3 in skeletal muscle is associated with protection from diet-induced insulin resistance in mice. In patients with type 2 diabetes UCP3 protein in muscle is reduced by 50% compared to healthy controls. The primary physiological role of the novel UCPs does not appear to be protection against positive energy balance and obesity; this is based largely on findings from studies of UCP2 and UCP3 knockout mice and from observed increases in UCP3 expression with fasting. The mechanism(s) of action of UCP2 and UCP3 are poorly understood. However, findings support roles for UCP2 and UCP3 as modifiers of fatty acid metabolism and in mitigating damage from reactive oxygen species.
PMID: 18220632 CAMSID: cams820
Uncoupling proteins; insulin secretion; insulin resistance; reactive oxygen species; fatty acid metabolism
Pre-eclampsia, a syndrome usually accompanied by incomplete spiral arterial modification, occurs at increased frequency in diabetic women. Hyperglycemia in type 1 diabetic non-obese diabetic (NOD) mice impairs gestational spiral arterial remodelling despite high local levels of interferon gamma (Ifng), the triggering cytokine in mice. Pregnancies in NOD.Ifng−/− mice were assessed to investigate this enigma.
Fecundity was assessed using breeding history, flushing of pre-implantation embryos and histological and morphometric studies of implantation sites in normoglycemic (n-) and hyperglycemic (d-) females of NOD.Ifng−/− and NOD genotypes.
NOD.Ifng−/− but not NOD mice are infertile. In NOD.Ifng−/−, copulation often does not result in postimplantation pregnancy. Defective fertilization and delayed pre-implantation development limit n-NOD.Ifng−/− fertility; both mechanisms are exacerbated by hyperglycemia. At midgestation, implantation sites in n-NOD.Ifng−/− and n-NOD mice are histologically similar. In d-NOD.Ifng−/−, there is minimal development of spiral arteries, hypertrophy of the myometrial region containing uterine Natural Killer (uNK) cells and a deficit in cytoplasmic granule formation in the uNK cells.
Ifng contributes to the success of fertilization and to the rate of pre-implantation mouse embryo development in normogylcemic and hyperglycemic pregnancies. A physiological role for this cytokine in human pre-implantation development merits investigation.
PMID: 20813805 CAMSID: cams1499
diabetes; placenta; pregnancy; spiral arterial modification; uterine Natural Killer cells
Interferon-γ–release assays (IGRAs) are alternatives to the tuberculin skin test (TST). A recent meta-analysis showed that IGRAs have high specificity, even among populations that have received bacille Calmette–Guérin (BCG) vaccination. Sensitivity was suboptimal for TST and IGRAs.
To incorporate newly reported evidence from 20 studies into an updated meta-analysis on the sensitivity and specificity of IGRAs.
PubMed was searched through 31 March 2008, and citations of all original articles, guidelines, and reviews for studies published in English were reviewed.
Studies that evaluated QuantiFERON-TB Gold, QuantiFERON-TB Gold In-Tube (both from Cellestis, Victoria, Australia), and T-SPOT.TB (Oxford Immunotec, Oxford, United Kingdom) or its precommercial ELISpot version, when data on the commercial version were lacking. For assessing sensitivity, the study sample had to have microbiologically confirmed active tuberculosis. For assessing specificity, the sample had to comprise healthy, low-risk individuals without known exposure to tuberculosis. Studies with fewer than 10 participants and those that included only immunocompromised participants were excluded.
One reviewer abstracted data on participant characteristics, test characteristics, and test performance from 38 studies; these data were double-checked by a second reviewer. The original investigators were contacted for additional information when necessary.
A fixed-effects meta-analysis with correction for overdispersion was done to pool data within prespecified subgroups. The pooled sensitivity was 78% (95% CI, 73% to 82%) for QuantiFERON-TB Gold, 70% (CI, 63% to 78%) for QuantiFERON-TB Gold In-Tube, and 90% (CI, 86% to 93%) for T-SPOT.TB. The pooled specificity for both QuantiFERON tests was 99% among non–BCG-vaccinated participants (CI, 98% to 100%) and 96% (CI, 94% to 98%) among BCG-vaccinated participants. The pooled specificity of T-SPOT.TB (including its precommercial ELISpot version) was 93% (CI, 86% to 100%). Tuberculin skin test results were heterogeneous, but specificity in non–BCG-vaccinated participants was consistently high (97% [CI, 95% to 99%]).
Most studies were small and had limitations, including no gold standard for diagnosing latent tuberculosis and variable TST methods and cutoff values. Data on the specificity of the commercial T-SPOT.TB assay were limited.
The IGRAs, especially QuantiFERON-TB Gold and QuantiFERON-TB Gold In-Tube, have excellent specificity that is unaffected by BCG vaccination. Tuberculin skin test specificity is high in non–BCG-vaccinated populations but low and variable in BCG-vaccinated populations. Sensitivity of IGRAs and TST is not consistent across tests and populations, but T-SPOT.TB appears to be more sensitive than both QuantiFERON tests and TST.
PMID: 18593687 CAMSID: cams235
The EBNA1 protein of Epstein-Barr virus enables the stable persistence of Epstein-Barr virus episomal genomes during latent infection, in part by tethering the episomes to the cellular chromosomes in mitosis. A host nucleolar protein, EBP2, has been shown to be important for EBNA1-chromosome interactions in metaphase and to associate with metaphase chromosomes. Here we examine the timing of the chromosome associations of EBNA1 and EBP2 through mitosis and the regions of EBNA1 that mediate the chromosome interactions at each stage of mitosis. We show that EBP2 is localized to the nucleolus until late prophase, then relocalizes to the chromosome periphery where it remains through telophase. EBNA1 is associated with the chromosomes early in prophase through to telophase and partially co-localizes with chromosomal EBP2 in metaphase through to telophase. Using EBNA1 deletion mutants, the chromosome association of EBNA1 at each stage of mitosis was found to be largely mediated by a central Gly-Arg region and to a lesser degree by N-terminal sequences and these sequence requirements for chromosome interaction mirrored those for EBP2 binding. The results suggest that EBNA1-chromosome interactions involve at least 2 stages and that the contribution of EBP2 to these interactions occurs in the second half of mitosis.
PMID: 19887584 CAMSID: cams1112
Epstein-Barr virus; segregation; chromosome periphery; nucleolus; EBNA1; EBP2
Microglia are increasingly recognized as critical in the pathogenesis of pain hypersensitivity caused by injury to peripheral nerves. The core signalling pathway is through P2X4 purinergic receptors on the microglia which, via the release brain derived neurotrophic factor, cause disinhibition of nociceptive dorsal horn neurons by raising intracellular chloride levels. This disinhibition works in synergy with enhanced excitatory synaptic transmission in the dorsal horn to transform the output of the nociceptive network. There is increased discharge output, unmasking of responses to innocuous peripheral inputs, and spontaneous activity in neurons that otherwise only signal nociception. Together the changes caused by microglia-neuron signalling may account for the main symptoms neuropathic pain in humans.
PMID: 20817512 CAMSID: cams2733