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Biomedical subjects

E Sheldon

Publications and source records attributed to E Sheldon.

7 recordsLinked to original sources

Efficacy and safety of rofecoxib 12.5 mg and celecoxib 200 mg in two similarly designed osteoarthritis studies.

OBJECTIVE: To compare the lower osteoarthritis (OA) dose of rofecoxib to the recommended dose of celecoxib in two identically designed studies. METHODS: Patients with knee OA were randomized (2:2:1 ratio: rofecoxib 12.5 mg once daily (qd), celecoxib 200 mg qd, or placebo, respectively). The primary endpoint was patient global assessment of response to therapy (PGART) averaged over 6 weeks on a five-point scale. Rofecoxib would be declared at least as effective as celecoxib if the lower bound of the 95% confidence interval (95% CI) for difference in means was no lower than -0.5. Additional endpoints included Pain and Physical Function subscales of the Western Ontario and McMaster (WOMAC) OA Index. Adverse experiences (AEs) were recorded and combined from the two studies for analysis. RESULTS: Study 1 enrolled 395 patients (rofecoxib, n = 160; celecoxib, n = 157; placebo, n = 78). Study 2 enrolled 413 patients (rofecoxib, n = 159; celecoxib, n = 169; placebo, n = 85). Rofecoxib 12.5 mg was at least as effective as celecoxib 200 mg by PGART (Study 1 difference -0.09 [95% CI: -0.32, 0.14] and Study 2 difference 0.02 [95% CI: -0.20, 0.24]), and both were significantly (p < 0.001) more effective than placebo. Comparable efficacy was also seen for WOMAC Pain and Physical Function subscales with the active treatments. There was a significantly higher (p < 0.05) incidence of serious AEs with celecoxib than rofecoxib or placebo, none of which was drug-related. There were no significant differences in the pre-specified measurements of safety including drug-related AEs or discontinuations due to AEs, and the medications demonstrated similar safety as assessed by spontaneous reporting. CONCLUSIONS: Rofecoxib 12.5 mg and celecoxib 200 mg provided comparable efficacy over 6 weeks, and both were significantly more efficacious than placebo. The medications demonstrated similar safety compared to one another and placebo. The primary limitations of these studies were that they were only 6 weeks long and were powered for efficacy. Therefore, conclusions about long-term safety cannot be inferred.

Aged↗

Weak Gravitational Lensing by the Nearby Cluster Abell 3667.

We present two weak lensing reconstructions of the nearby (zcl=0.055) merging cluster Abell 3667, based on observations taken approximately 1 yr apart under different seeing conditions. This is the lowest redshift cluster with a weak lensing mass reconstruction to date. The reproducibility of features in the two mass maps demonstrates that weak lensing studies of low-redshift clusters are feasible. These data constitute the first results from an X-ray luminosity-selected weak lensing survey of 19 low-redshift (z<0.1) southern clusters.

Journal Article↗

Amyloid precursor proteins protect neurons of transgenic mice against acute and chronic excitotoxic injuries in vivo.

The beta-amyloid protein precursor (APP) is well conserved across different species and may fulfill important physiological functions within the CNS. While high-level neuronal expression of amyloidogenic forms of human APP results in beta-amyloid production and neurodegeneration, lower levels of neuronal human APP expression in neurons of transgenic mice may primarily accentuate physiological functions of this molecule. To assess the neuroprotective potential of human APP in vivo, mice from seven distinct transgenic lines expressing different human APP isoforms from the neuron-specific enolase promoter were challenged with systemic kainate injections (n=30) or transgene-mediated glial expression of gp120 (n=32), an HIV-1 protein capable of inducing excitotoxic neuronal damage. To quantitate human APP-mediated neuroprotection. the area of neuropil occupied by presynaptic terminals and neuronal dendrites in the neocortex and hippocampus of each mouse was determined using laser scanning confocal microscopy of double-immunolabelled brain sections and computer-aided image analysis. Compared with gp120 singly transgenic controls, mice from three of three human APP751gp120 bigenic lines expressing the 751 amino acid form of human APP at low levels showed significant protection against degeneration of presynaptic terminals; two of these lines also showed significantly less damage to neuronal dendrites. Two of three human APP695/gp120 bigenic lines expressing human APP695 at low levels were protected against presynaptic and dendritic damage, whereas one low expressor line and a human APP695/gp120 bigenic line expressing human APP695 at higher levels showed no significant protection. In the corresponding human APP singly transgenic lines, overexpressing only specific human APP isoforms, significant protection against kainate-induced degeneration of presynaptic terminals and neuronal dendrites was found in two of three human APP751 lines and not in any of the four human APP695 lines tested. These results indicate that human APP can protect neurons against chronic and acute excitotoxic insults in vivo and that human APP isoforms differ in their neuroprotective potential, at least with respect to specific forms of neural injury. It is therefore possible that impairments of neuroprotective human APP functions or aberrant shifts in human APP isoform ratios could contribute to neurodegeneration.

Amyloid beta-Protein Precursor↗

Nonisotopic M13 probes for detecting the beta-globin gene: application to diagnosis of sickle cell anemia.

M13 DNA probes labeled with biotinylated psoralen and a streptavidin-horseradish peroxidase conjugate provide nonradioactive detection of the sickle cell and normal alleles of the beta-globin locus. The two biotinylated probes contain single-stranded sequences complementary to two different Sau3AI restriction fragments from the 5' region of the beta-globin gene and double-stranded M13 vector sequences. These probes are labeled with biotinylated psoralen photochemically linked to DNA. After hybridization, the presence of biotinylated probe bound to target DNA is detected in 3 h by using a streptavidin-horseradish peroxidase conjugate and the substrate, 3,3',5,5'-tetramethylbenzidine. Digestion of the normal (beta A) allele of the beta-globin gene with MstII (or isoschizomers) yields a 1.14-kb restriction fragment, while digestion of the mutant beta S allele yields a 1.34-kb fragment. These fragments can be resolved by gel electrophoresis and detected by Southern blot hybridization. The nonradioisotopic probe system can detect the beta-globin restriction fragment in as little as 0.5 microgram of human DNA and can distinguish heterozygotes (beta A beta S) from homozygotes (beta A beta A or beta S beta S) in 2.0 micrograms of human DNA.

Alleles↗

Cloning and sequence analysis reveal structural variation among related zein genes in maize.

We have isolated a gene encoding one of the 19,000 dalton zein proteins from a maize genomic library constructed in Charon 4A. This gene occurs on a 7.7 kb Eco RI fragment, and based on Southern hybridization analysis, represents one of several homologous sequences present in the maize genome. The nucleotide sequence of the gene predicts a protein composed of 235 amino acids, including a signal peptide of 21 amino acids. There are no intervening sequences in the gene. By comparing the nucleotide sequence of this gene with that of a homologous cDNA clone, we have identified a basis for microheterogeneity within the gene family. The 5' nucleotide sequences of the genomic and cDNA clones are identical, but they differ in the center of the protein, where repeated amino acid sequences occur. A nucleotide sequence encoding a conserved peptide of 20 amino acids is repeated nine times in the center of both of these clones.

Base Sequence↗