Randomised comparison of losartan vs. captopril on quality of life in elderly patients with symptomatic heart failure: the losartan heart failure ELITE quality of life substudy.

OBJECTIVE: To measure health-related quality-of-life (HRQoL) in elderly symptomatic heart failure patients following treatment with an angiotensin II receptor antagonist (losartan) vs. an angiotensin-converting-enzyme (ACE) inhibitor (captopril). METHODS: Patients (age > or = 65 years) were randomised to losartan, titrated to 50 mg once daily, or captopril, titrated to 50 mg three times daily, as tolerated. Sickness Impact Profile (SIP) and Minnesota Living with Heart Failure (LIhFE) questionnaires were administered at baseline, weeks 12 and 48. Composite hypothesis testing of change in HRQoL from baseline for completers, and withdrawal for unfavourable events (death, clinical/laboratory adverse experience) was used to account for differential dropout rates. RESULTS: In 203 patients completing the substudy (week 48), significant and comparable improvements in HRQoL from baseline were observed for both treatment groups (p < or = 0.001). Although there was a trend favouring losartan vs. captopril for the composite HRQoL endpoint (unadjusted p = 0.018, one-sided), this was not considered significant after adjusting for multiple testing. Significantly more captopril patients in the substudy subset withdrew for unfavourable reasons (19.6 vs. 10.9%, p = 0.038). CONCLUSIONS: Significant improvements in HRQoL were observed in elderly patients with symptomatic heart failure treated with losartan and captopril long-term. A trend favouring losartan in the composite measure of drug tolerability/quality of life was not significant, but losartan was generally better tolerated than captopril in that significantly fewer losartan patients discontinued therapy.

Quality control of oncology clinical trials.

This article discusses issues that are essential to ensuring the reliability of the conclusions of oncology clinical trials. Though quality control is important at every stage of a well-run clinical trial, the authors focus on the quality of the data as evidenced by the results and conclusions of the study. Good quality control principles and practices are discussed for study planning, design, conduct, analysis, and interpretation.

CoMFA-based prediction of agonist affinities at recombinant wild type versus serine to alanine point mutated D2 dopamine receptors.

Agonist affinity changes dramatically as a result of serine to alanine mutations (S193A, S194A, and S197A) within the fifth transmembrane region of D2 dopamine receptors and other receptors for monoamine neurotransmitters. However, agonist 2D-structure does not predict which drugs will be sensitive to which point mutations. Modeling drug-receptor interactions at the 3D level offers considerably more promise in this regard. In particular, a comparison of the same test set of agonists across receptors differing minimally (point mutations) offers promise to enhance the understanding of the structural bases for drug-receptor interactions. We have previously shown that comparative molecular field analysis (CoMFA) can be applied to comparisons of affinity at recombinant D1 and D2 dopamine receptors for the same set of agonists, a differential QSAR. Here, we predicted agonist K(L) for the same set of agonists at wild type D2 vs S193A, S194A, and S197A receptors using CoMFA. Each model used bromocriptine as the template. ln(1/K(L)) values for the low-affinity agonist binding conformation at recombinant wild type and mutant D2 dopamine receptors stably expressed in C6 glioma cells were used as the target property for the CoMFA of the 16 aligned agonist structures. The resulting CoMFA models yielded cross-validated R(2) (q(2)) values ranging from 0.835 to 0.864 and simple R(2) values ranging from 0.999 to 1.000. Predictions of test compound affinities at WT and each mutant receptor were close to measured affinity values. This finding confirmed the predictive ability of the models and their differences from one another. The results strongly support the idea that CoMFA models of the same training set of compounds applied to WT vs mutant receptors can accurately predict differences in drug affinity at each. Furthermore, in a "proof of principle", two different templates were used to derive the CoMFA model for the WT and S193A mutant receptors. Pergolide was chosen as an alternate template because it showed a significant increase in affinity as a result of the S193A mutation. In this instance both the bromocriptine- and pergolide-based CoMFA models were similar to one another but different from those for the WT receptor using bromocriptine- or pergolide- as templates. The pergolide-based S193A model was more strikingly different from that of the WT receptor than was the bromocriptine-based S193A model. This suggests that a "dual-template" approach to differential CoMFA may have special value in elucidating key differences across related receptor types and in determining important elements of the drug-receptor interaction.

Design and analysis of three treatment equivalence trials.

We consider design and analysis of clinical trials aimed at demonstrating equivalence of three treatments. We discuss analysis methods that require demonstrating that each pair of treatments has an unimportant difference. The critical values that we provide are smaller than the standard normal critical values, pointing out that the adjustment is counter to the usual multiplicity adjustments. Special issues in demonstrating equivalence of three rather than two treatments are discussed. We propose some conservative criteria for estimating sample size. Procedures for choosing pairs of treatments that are equivalent to each other, even when all three treatments are not shown equivalent, are also discussed along with implications for control of type I errors. We also demonstrate the methods with data from the literature.

On testing equivalence of three populations.

We consider analysis of clinical trials in which the objective is to show that three populations are equivalent. Equivalence is defined in terms of delta, the maximum difference in population means; a one-sided hypothesis test of delta is considered. We provide the distribution of the maximum pairwise difference in sample means, and we use this distribution to find critical values for tests of size 0.100, 0.050, 0.025, and 0.010. When standard errors are not equal among the three treatments, a simple adjustment is proposed to control the type I error rate. These tests are applied to studying the equivalence of three binomial proportions. Test-based confidence intervals are discussed. Two examples illustrate the proposed methods.

Concurrent administration of inactivated hepatitis A vaccine with immune globulin in healthy adults.

301 healthy adult volunteers were randomized to one of three treatment groups: inactivated hepatitis A vaccine alone; inactivated hepatitis A vaccine with immune globulin (Ig) concurrently; or Ig alone. The first two treatment groups received a second dose of hepatitis A vaccine at week 24. Anti-HAV was measured 4, 8, 12, 24 and 28 weeks after the primary immunization. When comparing subjects receiving inactivated hepatitis A vaccine alone to those receiving vaccine and Ig, the seropositivity rates were not significantly different at 4, 8, 12 and 28 weeks, but at week 24 the seropositivity rate was lower in the group receiving both vaccine and Ig compared to the group receiving vaccine alone (92.0% compared to 97.0%). At weeks 8, 12 and 24 the geometric mean titers (GMTs) were significantly lower for subjects receiving both vaccine and Ig. The GMTs were not significantly different after the second dose of vaccine. At all time points, the lower serum antibody concentrations observed in subjects receiving both inactivated hepatitis A vaccine and Ig were nevertheless substantially higher than the cutoff for assay seropositivity and much higher than after Ig alone; these differences are therefore clinically insignificant.

Short- and long-term heterologous sensitization of adenylate cyclase by D4 dopamine receptors.

The D4 dopamine receptor, a member of the D2-like dopamine receptor family, may be important in the etiology and treatment of schizophrenia. The present study was designed to examine the effects of dopamine agonist exposure on adenylate cyclase activity in HEK293 cells stably expressing recombinant-D4 receptors. Two hour pretreatment with dopamine receptor agonists resulted in heterologous sensitization of forskolin-stimulated cyclic AMP accumulation in intact cells expressing the D4.2, D4.4, or D4.7 dopamine receptor variant. The potency and efficacy of dopamine for sensitization of cyclic AMP accumulation was comparable at all D4 receptor variants. D4 dopamine receptor-mediated sensitization was blocked by the D4 antagonist, clozapine, and prevented by overnight pretreatment with pertussis toxin, implying a role for Gi/Go proteins in heterologous sensitization. Further, long-term (18 h) agonist exposure resulted in a greater degree of sensitization of forskolin-stimulated cyclic AMP accumulation in both intact cells and membrane preparations of cells expressing the D4 receptor, compared to 2 h agonist exposure, without altering the density of the receptors. In addition, long-term agonist exposure decreased the abundance of Gialpha without altering the abundance of Gsalpha, whereas short-term agonist treatment had no effect on the immunoreactivity of either G protein. In summary, long-term agonist-induced sensitization of adenylate cyclase by the D4 receptor may involve mechanisms that do not contribute to short-term sensitization.

Selective activation of Galphao by D2L dopamine receptors in NS20Y neuroblastoma cells.

D2L dopamine receptor activation results in rapid inhibition and delayed heterologous sensitization of adenylate cyclase in several host cell types. The D2L dopamine receptor was stably transfected into NS20Y neuroblastoma cells to examine inhibition and sensitization in a neuronal cell environment and to identify the particular G-proteins involved. Acute activation of D2L receptors with the selective D2 agonist quinpirole inhibited forskolin-stimulated cAMP accumulation, whereas prolonged incubation (2 hr) with quinpirole resulted in heterologous sensitization (more than twofold) of forskolin-stimulated cAMP accumulation in NS20Y-D2L cells. To unambiguously identify the pertussis toxin (PTX)-sensitive G-proteins responsible for inhibition and sensitization, we used viral-mediated gene delivery to assess the ability of genetically engineered PTX-resistant G-proteins (Galphai1*, Galphai2*, Galphai3*, and Galphao*) to rescue both responses after PTX treatment. The expression and function of individual recombinant G-proteins was confirmed with Western blotting and inhibition of GTPgammaS-stimulated adenylate cyclase, respectively. To assess the specificity of D2L-Galpha coupling, cells were infected with herpes simplex virus (HSV) recombinants expressing individual PTX-resistant G-protein alpha subunits and treated with PTX, and quinpirole-induced responses were measured. Infection of NS20Y-D2L cells with HSV-Galphao* rescued both inhibition and sensitization in PTX-treated cells, whereas infection with HSV-Galphai1*, HSV-Galphai2*, or HSV-Galphai3* failed to rescue either response. In summary, the current study provides strong evidence that the D2L dopamine receptor couples to Galphao in neuronal cells, and that this coupling is responsible for both the acute and subacute effects of D2 receptor activation on adenylate cyclase activity.

Contribution of serine residues to constitutive and agonist-induced signaling via the D2S dopamine receptor: evidence for multiple, agonist-specific active conformations.

Dopamine D2 receptors contain a cluster of serine residues in the fifth transmembrane domain that contribute to activation of the receptor as well as to the binding of agonists. We used rat D2S dopamine receptor mutants, each containing a serine-to-alanine substitution (S193A, S194A, S197A), to investigate the mechanism through which these residues affect activation of the receptor. Activation of the mutant receptor S194A was abolished in an agonist-dependent manner, such that dopamine no longer inhibited cAMP accumulation in C6 glioma cells or activated G protein-regulated K+ channels in Xenopus laevis oocytes, whereas the efficacy of several other agonists was unaffected. Dihydrexidine did not inhibit cAMP accumulation at either S193A or S194A. The decreased efficacy of dihydrexidine at S193A and S194A and dopamine at S194A was associated with a decreased ability to detect a GTP-sensitive high affinity binding state for these agonists. The ability of dopamine to stimulate [35S]guanosine-5'-O-(3-thio)triphosphate binding via S194A also was decreased by approximately 50%. Finally, constitutive stimulation of [35S]guanosine-5'-O-(3-thio)triphosphate binding and inhibition of adenylate cyclase by the D2S receptor was reduced by mutation of either S193 or S194. These data support the existence of multiple active receptor conformations that are differentially sensitive to mutation of serine residues in the fifth-transmembrane domain.

Duration of protection from clinical hepatitis A disease after vaccination with VAQTA.

Recent papers examining the expected persistence of anti-hepatitis A virus antibody following vaccination with inactivated hepatitis A vaccine have estimated that geometric mean antibody levels will remain above cut-off levels for 10-30 years. However, the methodology used in these papers did not take into account any estimates of variability between subjects. In this paper data from the persistence of antibody after the administration of another vaccine, VAQTA (hepatitis A vaccine, inactivated; MSD), were used to develop further models of antibody decay. Using individual subject estimates instead of group means allowed the estimation of time to negativity for various percentiles of the population (including the median), and the construction of confidence intervals on estimates of time to negativity. Data from studies of subjects who seroreverted to negativity, and subsequently received a booster dose, were also considered to show that subjects who lose detectable antibody are likely to remain protected from hepatitis A disease by persistent immune memory and rapid anamnestic response soon after exposure to hepatitis A virus. The estimates of duration of protection suggest that VAQTA will provide protection for many years, first through presence of antibody and further through an anamnestic response based on persistent immune memory.

Neurotransmitter regulation of the heart in the nudibranch Archidoris montereyensis.

1. The heart of the nudibranch mollusc Archidoris montereyensis is uniquely responsive to regulation by identifiable cardiac motor neurons. The neurotransmitters mediating the strong excitatory and inhibitory actions of the neurons are unknown. 2. In this study we developed an infused, in vitro preparation of the Archidoris heart to determine which of several cardioactive transmitters described in mollusks could affect changes in the rate, amplitude, or tonus of cardiac contractions. Several neurotransmitters we tested increased the rate and amplitude of heart contractions, including serotonin (threshold < 10 nM), dopamine (100 nM), and the neuropeptides R15 alpha 2 (3 nM), small cardioactive peptide B (10 nM), and FMRFamide (20 microM). Myomodulin also excited the heart (0.8 microM) and potentiated the cardioexcitatory action of serotonin at subthreshold concentrations. 3. Only acetylcholine (10 nM) inhibited the heart, decreasing the rate, amplitude, and tonus of contraction. Glycine and the peptides substance P and R15 alpha 1 had no effect on the heart. 4. Antisera against the active neurotransmitters labeled central neurons and nerves innervating the heart in a pattern consistent with their putative cardioregulatory functions. 5. Thus, despite the simplicity of the cardiac motor circuit in Archidoris, contractile activity of the heart appears to be regulated by several neurotransmitters, each with subtly different modes and thresholds of action.

Antibody responses of healthy infants to a recombinant hepatitis B vaccine administered at two, four, and twelve or fifteen months of age.

Hepatitis B vaccine was administered to healthy infants on two investigational schedules that fall within ranges recommended by the U.S. Public Health Service Advisory Committee on Immunization Practices and by the American Academy of Pediatrics Committee on Infectious Diseases. A month after receiving vaccine at 2, 4, and 12 or 15 months of age, 98% and 100% of the children had > 10 mIU antibodies to hepatitis B surface antigen per milliliter, with gemometric mean titers of 1358 mIU/ml and 3424 mIU/mL, respectively.

Neuroendocrine control of egg-laying behavior in the nudibranch, Archidoris montereyensis.

We describe a group of neurons with egg-laying bioactivity in the cerebral ganglia of an opisthobranch mollusc, the nudibranch Archidoris montereyensis. These cells, the intercerebral white cells (IWCs), share morphological, biochemical, and electrophysiological characteristics with the egg-laying neuroendocrine cells of two other molluscs, Aplysia californica (bag cells) and Lymnaea stagnalis (caudodorsal cells). The IWCs, comprising two superficial clusters of about 100 neurons each, were located immediately posterior to the intercerebral commissure in the cerebral ganglia. The somata of these cells were small (< 20 microns) and possessed varicose, bifurcating unipolar processes that collectively formed a loop within the commissure and bilateral extensions into the cerebral ganglia. The IWC clusters and commissural processes were enveloped by a large ganglionic vascular sinus, forming a potential neurohemal release site. Homogenates of whole cerebral ganglia or isolated IWC clusters induced egg-laying behavior within hours of injection into the hemocoel of quiescent animals. The IWCs were immunoreactive for alpha bag-cell peptide, one of the neuropeptide transmitters encoded by the egg-laying hormone gene of Aplysia. Electrophysiologically, the IWCs were silent neurons with large resting potentials and appeared to be highly refractory to electrical stimulation. The similarities of the IWCs to the egg-laying neuroendocrine cells in Aplysia and Lymnaea suggest that they are members of a homologous group of neurons controlling egg-laying behavior in gastropod molluscs.

Characterization of cardiac innervation in the nudibranch, Archidoris montereyensis.

The heart of the nudibranch mollusc Archidoris montereyensis is regulated by a small number of powerful effector neurons located in the right pleural and visceral ganglia. Two identifiable neurons in the pleural ganglion, a heart excitor (PlHE) and a heart inhibitor (PlHI), are especially important regulators of cardiac function in that low levels of spontaneous activity in either cell significantly alters the amplitude and rate of heart contractions. These neurons have extensive dendritic arbors within the right pleural ganglion and branching axonal processes within the visceral ganglion. The visceral ganglion also contains a heart excitor neuron (VHE) and at least two heart inhibitor neurons (VHI cells), but their influence on cardiac activity is weaker than that of the pleural ganglion cells. All of these heart effector cells appear to be motor neurons with axons that terminate predominantly in the atrio-ventricular valve region of the heart via the pericardial nerve. The simplicity and strength of these neuronal connections to the heart of Archidoris make this a favorable preparation for studies of cardiac regulation.