Biomedical subjects

Steven Gottlieb

Publications and source records attributed to Steven Gottlieb.

5 recordsLinked to original sources

PubMed2006

Recessive symptomatic focal epilepsy and mutant contactin-associated protein-like 2.

Contactin-associated protein-like 2 (CASPR2) is encoded by CNTNAP2 and clusters voltage-gated potassium channels (K(v)1.1) at the nodes of Ranvier. We report a homozygous mutation of CNTNAP2 in Old Order Amish children with cortical dysplasia, focal epilepsy, relative macrocephaly, and diminished deep-tendon reflexes. Intractable focal seizures began in early childhood, after which language regression, hyperactivity, impulsive and aggressive behavior, and mental retardation developed in all children. Resective surgery did not prevent the recurrence of seizures. Temporal-lobe specimens showed evidence of abnormalities of neuronal migration and structure, widespread astrogliosis, and reduced expression of CASPR2.

Child↗

PubMed2005

Charmed-meson decay constants in three-flavor lattice QCD.

We present the first lattice QCD calculation with realistic sea quark content of the D+-meson decay constant f(D+). We use the MILC Collaboration's publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). We obtain f(D+)=201+/-3+/-17 MeV, where the errors are statistical and a combination of systematic errors. We also obtain f(Ds)=249+/-3+/-16 MeV for the Ds meson.

Journal Article↗

PubMed2005

Impact of nonfatal myocardial infarction on outcomes in patients with advanced heart failure and the effect of bucindolol therapy.

We sought to identify the clinical characteristics and outcomes of patients who had advanced heart failure and nonfatal myocardial infarction (MI) in the beta-Blocker Evaluation of Survival Trial (BEST) and to investigate whether bucindolol alters the risk of developing nonfatal MI. Of the 2,708 patients enrolled in the study, 142 had suspected MI and 69 had confirmed MI; there were 860 deaths overall. The rate of nonfatal MI in the BEST was low over the 4.1 years of follow-up (4.8% had suspected events and 2.4% had adjudicated events) and was similar to that in high-risk populations. Cox's proportional hazard model with 23 prespecified candidate variables associated advanced age, heart failure symptoms, male gender, ischemic etiology, diabetes, and hypertension with nonfatal MI or cardiovascular death. The 2-year mortality rate was 56% for the cohort that had suspected nonfatal MI versus 30% for the cohort that did not (p = 0.01). Likewise, the risk of hospitalization for congestive heart failure was twofold greater. Beta-blocker therapy with bucindolol resulted in a 52% decrease in suspected nonfatal MI (2.9% vs 5.5%, p = 0.001). In conclusion, nonfatal MI occurs at low rates but increases the risks for mortality and hospitalization in patients who have advanced heart failure. Beta-blocker therapy with bucindolol appears to attenuate the risk of nonfatal MI in this population.

Adrenergic beta-Antagonists↗

PubMed2005

Semileptonic decays of d mesons in three-flavor lattice QCD.

We present the first three-flavor lattice QCD calculations for D-->pilnu and D-->Klnu semileptonic decays. Simulations are carried out using ensembles of unquenched gauge fields generated by the MILC Collaboration. With an improved staggered action for light quarks, we are able to simulate at light quark masses down to 1/8 of the strange mass. Consequently, the systematic error from the chiral extrapolation is much smaller than in previous calculations with Wilson-type light quarks. Our results for the form factors at q(2)=0 are f(D-->pi)(+)(0)=0.64(3)(6) and f(D-->K)(+)(0)=0.73(3)(7), where the first error is statistical and the second is systematic, added in quadrature. Combining our results with experimental branching ratios, we obtain the Cabibbo-Kobayashi-Maskawa matrix elements |V(cd)|=0.239(10)(24)(20) and |V(cs)|=0.969(39)(94)(24), where the last errors are from experimental uncertainties.

Journal Article↗

PubMed2004

High-precision lattice QCD confronts experiment.

The recently developed Symanzik-improved staggered-quark discretization allows unquenched lattice-QCD simulations with much smaller (and more realistic) quark masses than previously possible. To test this formalism, we compare experiment with a variety of nonperturbative calculations in QCD drawn from a restricted set of "gold-plated" quantities. We find agreement to within statistical and systematic errors of 3% or less. We discuss the implications for phenomenology and, in particular, for heavy-quark physics.

Journal Article↗