Biomedical subjects

Brian Howard

Publications and source records attributed to Brian Howard.

4 recordsLinked to original sources

PubMed2006

Engineering the catalytic domain of human protein tyrosine phosphatase beta for structure-based drug discovery.

Protein tyrosine phosphatases (PTPs) play roles in many biological processes and are considered to be important targets for drug discovery. As inhibitor development has proven challenging, crystal structure-based design will be very helpful to advance inhibitor potency and selectivity. Successful application of protein crystallography to drug discovery heavily relies on high-quality crystal structures of the protein of interest complexed with pharmaceutically interesting ligands. It is very important to be able to produce protein-ligand crystals rapidly and reproducibly for as many ligands as necessary. This study details our efforts to engineer the catalytic domain of human protein tyrosine phosphatase beta (HPTPbeta-CD) with properties suitable for rapid-turnaround crystallography. Structures of apo HPTPbeta-CD and its complexes with several novel small-molecule inhibitors are presented here for the first time.

Binding Sites↗

PubMed2006

Cortical progenitor cells in the developing human telencephalon.

Radial glial (RG) cells have been demonstrated to be a major neural progenitor cell type, but in the human fetal brain, neither their molecular nor their spatiotemporal characteristics are well known. We used glial and neuronal-specific antibodies to determine the antigen characteristics and distribution of RG cells and other neuronal progenitors in the human brain during the first half of intrauterine development. Proliferating RG (4A4+) cells in the ventricular zone (VZ) showed clear caudorostral and ventrodorsal gradients, spreading from the spinal cord to the ventral rhombencephalon, at embryonic stages (4.5-5.5 gestational weeks [gw]). However, in the same embryo, other dividing cells expressed the neuronal marker SMI-31 and were present throughout the entire CNS, including the rostral prosencephalon. At the beginning of cortical neurogenesis (6 gw), proliferating VZ cells labeled either with neuronal markers (SMI-31, MAP2, beta-III-tubulin), double-labeled 4A4(+)/SMI-31+ cells, or cells not labeled with these antibodies, were in close proximity to each other. At midgestation (17-24 gw), RG divisions were less frequent, but were spread throughout the entire cerebral cortex, including the subventricular and intermediate zones and the subpial granular layer. Several subtypes of RG were co-labeled with vimentin and other glial markers (BLBP, GFAP, or GLAST) and quantified in vitro. In conclusion, the diversity of cortical progenitors in the human brain may, in part, explain the unique complexity of the human cerebral cortex.

Aborted Fetus↗

PubMed2006

Knowing how to help tobacco users. Dentists' familiarity and compliance with the clinical practice guideline.

BACKGROUND: A U.S. Public Health Service-sponsored clinical practice guideline urges all health care providers to make tobacco-use cessation counseling a routine part of clinical practice. This study assessed practices of dentists in east Texas, their adherence to the guideline and barriers to adherence. METHODS: A cross-sectional survey mailed September 2003 through January 2004 assessed demographic characteristics and knowledge, attitudes and activities of 783 dentists. The survey focused on familiarity with the guideline, adherence to the recommended steps (including the "5 A's" for tobacco users willing to quit and the "5 R's" for tobacco users unwilling to quit), perceived barriers and time spent counseling. RESULTS: Most dentists were unfamiliar with the guideline and usually did not follow its recommended steps. Less than 20 percent of dentists spent three or more minutes per patient on counseling. Knowledge of and training in using the guideline were significantly associated with adherence and time spent counseling. Lack of training was cited as the greatest barrier. CONCLUSIONS: Most dentists in east Texas are unaware of the clinical practice guideline. Lack of training is a major barrier to adherence. Practice Implications. Opportunities for improving patients' health through brief counseling interventions are missed. Measures are needed to increase dentists' familiarity with and adherence to the guideline.

Adult↗

PubMed2003

Effect of vaccination with a recombinant fusion protein encoding an astacinlike metalloprotease (MTP-1) secreted by host-stimulated Ancylostoma caninum third-stage infective larvae.

Laboratory dogs were vaccinated intramuscularly with a recombinant fusion protein (expressed and isolated from Escherichia coli) formulated with the Glaxo SmithKline Adjuvant System 02 (AS02). The fusion protein encoded Ac-MTP-1, a developmentally regulated astacinlike metalloprotease secreted by host-stimulated Ancylostoma caninum third-stage larvae (L3). Control dogs were injected intramuscularly with an equivalent amount of AS02 adjuvant alone. The vaccinated and control dogs were then challenged by s.c. injection of 500 L3 of the canine hookworm A. caninum. The vaccinated dogs developed prechallenge immunoglobulin G2 (IgG2) antibody responses specific to anti-Ac-MTP-1-fusion protein with titers ranging between 1:40,000 and 1:364,000, whereas they developed antigen-specific immunoglobulin E antibody responses with titers ranging between 1:500 and 1:1,500. By immunoblotting, canine sera obtained from the vaccinated dogs recognized a protein of the estimated apparent molecular weight of Ac-MTP-1 in activated L3 secretory products. Spearman rank order correlations between the canine intestinal adult hookworm burden and quantitative egg counts at necropsy and anti-Ac-MTP-1 IgG2 antibody titers revealed a statistically significant inverse association (r = -0.89; P = 0.04), suggesting that this molecule offers promise as a recombinant vaccine.

Adjuvants, Immunologic↗