129 research outputs found
Bipolar Disorder and the TCI: Higher Self-Transcendence in Bipolar Disorder Compared to Major Depression
Personality traits are potential endophenotypes for genetic studies of psychiatric disorders. One personality theory which demonstrates strong heritability is Cloninger's psychobiological model measured using the temperament and character inventory (TCI).
277 individuals who completed the TCI questionnaire as part of the South Island Bipolar Study were also interviewed to assess for lifetime psychiatric diagnoses. Four groups were compared, bipolar disorder (BP), type 1 and 2, MDD (major depressive disorder), and nonaffected relatives of a proband with BP.
With correction for mood state, total harm avoidance (HA) was higher than unaffected in both MDD and BP groups, but the mood disorder groups did not differ from each other. However, BP1 individuals had higher self-transcendence (ST) than those with MDD and unaffected relatives. HA may reflect a trait marker of mood disorders whereas high ST may be specific to BP. As ST is heritable, genes that affect ST may be of relevance for vulnerability to BP
Urocortin 2 Infusion in Healthy Humans Hemodynamic, Neurohormonal, and Renal Responses
ObjectivesWe sought to examine the effects of urocortin (UCN) 2 infusion on hemodynamic status, cardiovascular hormones, and renal function in healthy humans.BackgroundUrocortin 2 is a vasoactive and cardioprotective peptide belonging to the corticotrophin-releasing factor peptide family. Recent reports indicate the urocortins exert important effects beyond the hypothalamo-pituitary-adrenal axis upon cardiovascular and vasohumoral function in health and cardiac disease.MethodsWe studied 8 healthy unmedicated men on 3 separate occasions 2 to 5 weeks apart. Subjects received placebo, 25-μg low-dose (LD), and 100-μg high-dose (HD) of UCN 2 intravenously over the course of 1 h in a single-blind, placebo-controlled, dose-escalation design. Noninvasive hemodynamic indexes, neurohormones, and renal function were measured.ResultsThe administration of UCN 2 dose-dependently increased cardiac output (mean peak increments ± SEM) (placebo 0.5 ± 0.2 l/min; LD 2.1 ± 0.6 l/min; HD 5.0 ± 0.8 l/min; p < 0.001), heart rate (placebo 3.3 ± 1.0 beats/min; LD 8.8 ± 1.8 beats/min; HD 17.8 ± 2.1 beats/min; p < 0.001), and left ventricular ejection fraction (placebo 0.6 ± 1.4%; LD 6.6 ± 1.5%; HD 14.1 ± 0.8%; p < 0.001) while decreasing systemic vascular resistance (placebo −128 ± 50 dynes·s/cm5; LD −407 ± 49 dynes·s/cm5; HD −774 ± 133 dynes·s/cm5; p < 0.001). Activation of plasma renin activity (p = 0.002), angiotensin II (p = 0.001), and norepinephrine (p < 0.001) occurred only with the higher 100-μg dose. Subtle decreases in urine volume (p = 0.012) and natriuresis (p = 0.001) were observed.ConclusionsBrief intravenous infusions of UCN 2 in healthy humans induced pronounced dose-related increases in cardiac output, heart rate, and left ventricular ejection fraction while decreasing systemic vascular resistance. Subtle renal effects and activation of plasma renin, angiotensin II, and norepinephrine (at high-dose only) were observed. These findings warrant further investigation of the role of UCN 2 in circulatory regulation and its potential therapeutic application in heart disease
A Hexagonal Theory of Flavor
We construct a supersymmetric theory of flavor based on the discrete gauge
group (D_6)^2, where D_6 describes the symmetry of a regular hexagon under
proper rotations in three dimensions. The representation structure of the group
allows one to distinguish the third from the lighter two generations of matter
fields, so that in the symmetry limit only the top quark Yukawa coupling is
allowed and scalar superpartners of the first two generations are degenerate.
Light fermion Yukawa couplings arise from a sequential breaking of the flavor
symmetry, and supersymmetric flavor-changing processes remain adequately
suppressed. We contrast our model with others based on non-Abelian discrete
gauge symmetries described in the literature, and discuss the challenges in
constructing more minimal flavor models based on this approach.Comment: 19 pages, ReVTeX, 1 eps figur
The utility of presentation and 4-hour high sensitivity troponin I to rule-out acute myocardial infarction in the emergency department
Objectives: International guidance recommends that early serial sampling of high sensitivity troponin be used to accurately identify acute myocardial infarction (AMI) in chest pain patients. The background evidence for this approach is limited. We evaluated whether on presentation and 4-hour high-sensitivity troponin I (hs-cTnI) could be used to accurately rule-out AMI. Design and methods: hs-cTnI was measured on presentation and at 4-hours in adult patients attending an emergency department with possible acute coronary syndrome. We determined the sensitivity for AMI for at least one hs-cTnI above the 99th percentile for a healthy population or alone or in combination with new ischemic ECG changes. Both overall and sex-specific 99th percentiles were assessed. Patients with negative tests were designated low-risk. Results: 63 (17.1%) of 368 patients had AMI. The median (interquartile range) time from symptom onset to first blood sampling was 4.8. h (2.8-8.6). The sensitivity of the presentation and 4. h hs-cTnI using the overall 99th percentile was 92.1% (95% CI 82.4% to 97.4%) and negative predictive value 95.4% (92.3% to 97.4%) with 78.3% low-risk. Applying the sex-specific 99th percentile did not change the sensitivity. The addition of ECG did not change the sensitivity. Conclusion: Hs-cTnI >. 99th percentile thresholds measured on presentation and at 4-hours was not a safe strategy to rule-out AMI in this clinical setting irrespective of whether sex-specific 99th percentiles were used, or whether hs-cTnI was combined with ECG results
Betaine and Secondary Events in an Acute Coronary Syndrome Cohort
BACKGROUND: Betaine insufficiency is associated with unfavourable vascular risk profiles in metabolic syndrome patients. We investigated associations between betaine insufficiency and secondary events in acute coronary syndrome patients. METHODS: Plasma (531) and urine (415) samples were collected four months after discharge following an acute coronary event. Death (34), secondary acute myocardial infarction (MI) (70) and hospital admission for heart failure (45) events were recorded over a median follow-up of 832 days. PRINCIPAL FINDINGS: The highest and lowest quintiles of urinary betaine excretion associated with risk of heart failure (p = 0.0046, p = 0.013 compared with middle 60%) but not with subsequent acute MI. The lowest quintile of plasma betaine was associated with subsequent acute MI (p = 0.014), and the top quintile plasma betaine with heart failure (p = 0.043), especially in patients with diabetes (p<0.001). Top quintile plasma concentrations of dimethylglycine (betaine metabolite) and top quintile plasma homocysteine both associated with all three outcomes, acute MI (p = 0.004, <0.001), heart failure (p = 0.027, p<0.001) and survival (p<0.001, p<0.001). High homocysteine was associated with high or low betaine excretion in >60% of these subjects (p = 0.017). Median NT-proBNP concentrations were lowest in the middle quintile of plasma betaine concentration (p = 0.002). CONCLUSIONS: Betaine insufficiency indicates increased risk of secondary heart failure and acute MI. Its association with elevated homocysteine may partly explain the disappointing results of folate supplementation. In some patients, especially with diabetes, elevated plasma betaine also indicates increased risk
Effect of B-type natriuretic peptide-guided treatment of chronic heart failure on total mortality and hospitalization: an individual patient meta-analysis
Aims Natriuretic peptide-guided (NP-guided) treatment of heart failure has been tested against standard clinically guided care in multiple studies, but findings have been limited by study size. We sought to perform an individual patient data meta-analysis to evaluate the effect of NP-guided treatment of heart failure on all-cause mortality. Methods and results Eligible randomized clinical trials were identified from searches of Medline and EMBASE databases and the Cochrane Clinical Trials Register. The primary pre-specified outcome, all-cause mortality was tested using a Cox proportional hazards regression model that included study of origin, age (45%) as covariates. Secondary endpoints included heart failure or cardiovascular hospitalization. Of 11 eligible studies, 9 provided individual patient data and 2 aggregate data. For the primary endpoint individual data from 2000 patients were included, 994 randomized to clinically guided care and 1006 to NP-guided care. All-cause mortality was significantly reduced by NP-guided treatment [hazard ratio = 0.62 (0.45-0.86); P = 0.004] with no heterogeneity between studies or interaction with LVEF. The survival benefit from NP-guided therapy was seen in younger (<75 years) patients [0.62 (0.45-0.85); P = 0.004] but not older (≥75 years) patients [0.98 (0.75-1.27); P = 0.96]. Hospitalization due to heart failure [0.80 (0.67-0.94); P = 0.009] or cardiovascular disease [0.82 (0.67-0.99); P = 0.048] was significantly lower in NP-guided patients with no heterogeneity between studies and no interaction with age or LVEF. Conclusion Natriuretic peptide-guided treatment of heart failure reduces all-cause mortality in patients aged <75 years and overall reduces heart failure and cardiovascular hospitalizatio
U(2)-like Flavor Symmetries and Approximate Bimaximal Neutrino Mixing
Models involving a U(2) flavor symmetry, or any of a number of its
non-Abelian discrete subgroups, can explain the observed hierarchy of charged
fermion masses and CKM angles. It is known that a large neutrino mixing angle
connecting second and third generation fields may arise via the seesaw
mechanism in these models, without a fine tuning of parameters. Here we show
that it is possible to obtain approximate bimaximal mixing in a class of models
with U(2)-like Yukawa textures. We find a minimal form for Dirac and Majorana
neutrino mass matrices that leads to two large mixing angles, and show that our
result can quantitatively explain atmospheric neutrino oscillations while
accommodating the favored, large angle MSW solution to the solar neutrino
problem. We demonstrate that these textures can arise in models by presenting a
number of explicit examples.Comment: 20 pages RevTex4, 2 figure
Orthogonal U(1)'s, Proton Stability and Extra Dimensions
In models with a low quantum gravity scale, one might expect that all
operators consistent with gauge symmetries are present in the low-energy
effective theory. If this is the case, some mechanism must be present to
adequately suppress operators that violate baryon number. Here we explore the
possibility that the desired suppression is a consequence of an additional,
spontaneously-broken, non-anomalous U(1) symmetry that is orthogonal to
hypercharge. We show that successful models can be constructed in which the
additional particle content necessary to cancel anomalies is minimal, and
compatible with the constraints from precision electroweak measurements and
gauge unification. If unification is sacrificed, and only the new U(1) and its
associated Higgs fields live in the bulk, it is possible that the gauge field
zero mode and first few Kaluza-Klein excitations lie within the kinematic reach
of the Tevatron. For gauge couplings not much smaller than that of hypercharge,
we show that these highly leptophobic states could evade detection at Run I,
but be discovered at Run II. Our scenario presents an alternative to the
`cartographic' solution to baryon number violation in which leptons and quarks
are separated in an extra dimension.Comment: 16 pages LaTeX, 4 figure
Derivation of Pre-X Inactivation Human Embryonic Stem Cells under Physiological Oxygen Concentrations
The presence of two active X chromosomes (XaXa) is a hallmark of the ground state of pluripotency specific to murine embryonic stem cells (ESCs). Human ESCs (hESCs) invariably exhibit signs of X chromosome inactivation (XCI) and are considered developmentally more advanced than their murine counterparts. We describe the establishment of XaXa hESCs derived under physiological oxygen concentrations. Using these cell lines, we demonstrate that (1) differentiation of hESCs induces random XCI in a manner similar to murine ESCs, (2) chronic exposure to atmospheric oxygen is sufficient to induce irreversible XCI with minor changes of the transcriptome, (3) the Xa exhibits heavy methylation of the XIST promoter region, and (4) XCI is associated with demethylation and transcriptional activation of XIST along with H3K27-me3 deposition across the Xi. These findings indicate that the human blastocyst contains pre-X-inactivation cells and that this state is preserved in vitro through culture under physiological oxygen.Susan WhiteheadHillel and Liliana Bachrac
Maximal Neutrino Mixing from a Minimal Flavor Symmetry
We study a number of models, based on a non-Abelian discrete group, that
successfully reproduce the simple and predictive Yukawa textures usually
associated with U(2) theories of flavor. These models allow for solutions to
the solar and atmospheric neutrino problems that do not require altering
successful predictions for the charged fermions or introducing sterile
neutrinos. Although Yukawa matrices are hierarchical in the models we consider,
the mixing between second- and third-generation neutrinos is naturally large.
We first present a quantitative analysis of a minimal model proposed in earlier
work, consisting of a global fit to fermion masses and mixing angles, including
the most important renormalization group effects. We then propose two new
variant models: The first reproduces all important features of the SU(5)xU(2)
unified theory with neither SU(5) nor U(2). The second demonstrates that
discrete subgroups of SU(2) can be used in constructing viable supersymmetric
theories of flavor without scalar universality even though SU(2) by itself
cannot.Comment: 34 pages LaTeX, 1 eps figure, minor revisions and references adde
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