Citations

AbstractUnderstanding of the conformational changes in G protein-coupled receptors associated with activation and inactivation is of great interest. We previously used photoaffinity labeling to elucidate spatial approximations between photolabile residues situated throughout the pharmacophore of secretin agonist probes and this receptor. The aim of the current work was to develop analogous photolabile secretin antagonist probes and to explore their spatial approximations. The most potent secretin antagonist reported is a pseudopeptide ([ψ4, 5]secretin) in which the peptide bond between residues 4 and 5 was replaced by a ψ(CH2-NH) peptide bond isostere. We have developed a series of [ψ4, 5]secretin analogs incorporating photolabile benzoyl phenylalanine residues in positions 6, 22, and 26. Each bound to the secretin receptor saturably and specifically, with affinity similar to their parental peptide. At concentrations with no measurable agonist activity, each probe covalently labeled the secretin receptor. Peptide mapping using proteolytic cleavage, immunoprecipitation, and radiochemical sequencing identified that each of these three probes labeled the amino terminus of the secretin receptor. Whereas the position 22 probe labeled the same residue as its analogous agonist probe and the position 6 probe labeled a residue within two residues of that labeled by its analogous agonist probe, the position 26 probe labeled a site 16 residues away from that labeled by its analogous agonist probe. Thus, whereas structurally related agonist and antagonist probes dock in the same general region of this receptor, conformational differences in active and inactive states result in substantial differences in spatial approximation at the carboxyl-terminal end of secretin analogs.

Abstract Rationale: Mycobacterium avium complex pulmonary disease (MAC-PD) is associated with substantial morbidity, and standard daily multidrug therapy is difficult to tolerate. Objectives To characterize response to a three-times-weekly (TIW) regimen of clarithromycin, ethambutol, and rifampin. Methods A 1-yr prospective noncomparative trial of TIW treatment was conducted during 2000–2003 in 17 U.S. cities. Participants were 91 HIV-negative adults, diagnosed with moderate to severe MAC-PD, who originally participated in a trial of an inhaled IFN-γ treatment. Improvement in sputum culture, high-resolution computed tomography (HRCT), and symptoms were assessed. Results Treatment response rates (and median response times) were 44% (2 mo or longer) for culture, 60% (5.5–11.5 mo) for HRCT, and 53% (8.5 mo) for symptoms. Having noncavitary, compared with cavitary, disease increased culture response by 4.0 times (95% confidence interval [CI], 1.7–9.2) and HRCT response by 4.9 times (95% CI, 1.9–13.0). Culture response was 1.5 times (95% CI, 1.1–2.2) higher for older subjects and 2.2 times (95% CI, 1.0–4.7) higher for previously untreated subjects. Being smear-negative increased culture response by 2.3 times (95% CI, 1.1–5.2) but decreased HRCT response by 4.4 times (95% CI, 1.7–11.5). Increasing ethambutol use by 5 mo increased culture response by 1.5 times (95% CI, 1.0–2.1) but decreased symptom response. Not having chronic obstructive pulmonary disease, bronchiectasis, or poor lung function increased symptom response by 1.9 to 3.9 times. Conclusions TIW therapy was less effective for MAC-PD patients with cavitary disease and a history of chronic obstructive pulmonary disease, bronchiectasis, or previous treatment for MAC-PD. Further research is needed to study the long-term outcomes of TIW treatment.

Activation of complement on endothelium triggers physiological changes that promote coagulation, thrombosis, and inflammation. Unlike agonists such as cytokines and endotoxin that induce these changes through transcription of many genes, complement, particularly the membrane attack complex, primarily induces release of IL-1α by the endothelial cells; the cytokine may then be removed by normal blood flow or may promote activation of the full range of endothelial cell responses in an autocrine or paracrine manner. We studied the intracellular signaling pathways used by complement to activate interleukin (IL)-1α transcription in cultured endothelial cells. The membrane attack complex and other pore-forming proteins stimulated calcineurin and activated selective transcription of the IL-1α gene. In contrast, the action of cytokines such as IL-1α was not selective and not dependent on calcineurin activity. Transcription of IL-1α, whether stimulated by complement and calcineurin or by “conventional agonists,” such as IL-1α independent of calcineurin, proceeded via binding of nuclear factor κB transcriptional activators to the IL-1α gene promoter. These findings define a molecular mechanism through which complement regulates IL-1α production by endothelial cells and explain how blood flow may determine the extent of complement-stimulated inflammation.

The purpose of this article is to examine the potential of brief intervention (BI) as a modality for translating health behavior intervention research into practice. We discuss common definitions of BI, applications within common models of translation research, effects of BI on a range of health behaviors and across various populations, current and potential mechanisms, and uses for dissemination to practice. A number of advantages of BI suggest they are well suited for translating behavioral research. In addition, findings from 13 systematic reviews of BI effects show their potential versatility. Basic research on motivation, decision making, and persuasion may be applied to the design of BIs (Type 1 translation). Suggestions for translating BI research into practice are discussed (Type 2 translation). The article concludes that efforts to use BIs to translate research into practice are currently underdeveloped. Recommendations are provided for using BI in translating research into practice.

A new interpositional elastomeric cap was developed and used for perichondrioplasty in six rheumatoid metacarpophalangeal joints. Adequate cartilage formation occurred, and the joint contours were more normal than those achieved by previous methods.

Antibodies are generally thought to be a class of proteins that function without the use of cofactors. However, it is not widely appreciated that antibodies are believed to be the major carrier protein in human circulation for the important riboflavin cofactor that is involved in a host of biological phenomena. A further link between riboflavin and antibodies was discovered 30 years ago when a bright-yellow antibody, IgG GAR , was purified from a patient with multiple myeloma who had turned yellow during the course of her disease. It was subsequently shown that the yellow color of this antibody was due to riboflavin binding. However, it was not known how and where riboflavin was bound to this antibody. We now report the crystal structure of this historically important IgG GAR Fab at 3.0-Å resolution. The riboflavin is located in the antigen-combining site with its isoalloxazine ring stacked between the parallel aromatic moieties of TyrH33, PheH58, and TyrH100A. Together with additional hydrogen bonds, these interactions reveal the structural basis for high-affinity riboflavin binding. The ligand specificity of IgG GAR is compared with another riboflavin-binding antibody, IgG DOT , which was purified from a second patient with multiple myeloma. The crystal structure of IgG GAR provides a starting point for attempts to understand the physiological relevance and chemical functions of cofactor-containing antibodies.

PurposeFulvestrant is an antiestrogen that leads to estrogen receptor degradation and has demonstrated efficacy in breast cancer patients who have had disease recurrence or progression after tamoxifen. This study was designed to examine the efficacy and toxicity of fulvestrant in patients with disease progression on a third-generation aromatase inhibitor (AI).Patients and MethodsA one-stage phase II trial was conducted in postmenopausal women with measurable disease by Response Evaluation Criteria in Solid Tumors criteria who experienced disease progression after treatment with a third-generation AI and, at most, one additional hormonal agent. Tumors must have been estrogen receptor and/or progesterone receptor positive. The primary end point was objective response rate, and secondary end points were time to disease progression, survival, duration of response, and toxicity.ResultsEighty patients were enrolled, and three were ineligible. Characteristics of the 77 eligible patients included median age of 68 years, performance score of 0 or 1 in 91% of patients, visceral dominant disease in 88% of patients, two prior hormonal treatments in 73% of patients, and prior chemotherapy for metastatic disease in 32% of patients. Eleven patients (14.3%) achieved a partial response, and 16 patients (20.8%) had stable disease for at least 6 months, for a clinical benefit rate of 35%. Antitumor activity seemed to be higher in women with prior treatment with AI alone compared with women whose prior treatment also included tamoxifen. Median time to progression was 3 months, and median survival time was 20.2 months. Fulvestrant was well tolerated.ConclusionFulvestrant is a well-tolerated treatment and has efficacy against breast cancers that have progressed after therapy with a third-generation AI.

Purpose To compare maintenance epoetin alfa administered once every 3 weeks with continued weekly epoetin alfa for patients with cancer-associated anemia. Patients and Methods Eligible patients were randomly assigned at enrollment to receive three weekly doses of epoetin alfa 40,000 U subcutaneously (SC), followed by either standard weekly epoetin alfa (40K arm) or 120,000 U of epoetin alfa (120K arm) SC every 3 weeks for 18 additional weeks. Results Three hundred sixty-five patients were enrolled. One hundred eighty-three patients were assigned to the 40K arm, and 182 were assigned to the 120K arm. There was no difference in the proportion of patients requiring transfusions during the study (23% in 40K arm and 18% in 120K arm, P = .22) or specifically during the maintenance phase (13% in 40K arm v 15% in 120K arm, P = .58). Patients randomly assigned to the 40K arm were more likely to have a ≥ 2 or ≥ 3 g/dL hemoglobin (Hb) increment, were more likely to have a drug dose held because of high Hb, and had higher mean end-of-study Hb levels. Toxicities, including thromboembolism, and overall survival were similar. Patients in the 40K arm had a higher global quality of life (QOL) at baseline for unclear reasons, whereas patients in the 120K arm had a greater global QOL improvement during the study, so end-of-study QOL was equivalent. Conclusion After three weekly doses of epoetin alfa 40,000 U, a dose of 120,000 U can be administered safely once every 3 weeks without increasing transfusion needs or sacrificing QOL. The Hb increment is somewhat greater with continued weekly epoetin alfa. Lack of blinding as a result of different treatment schedules may have confounded results.