How personal experiences feature in women's accounts of use of information for decisions about antenatal diagnostic testing for foetal abnormality

There has been a striking growth in the availability of health-related information based on personal experience in recent years and internet users are often drawn towards other people's stories about their health. Accounts of other people's experiences might convey social and emotional information that is not otherwise available but little is known about how it is used or the implications of its use in practice. This paper examines how people refer to information about other people's experiences when accounting for decisions about antenatal diagnostic testing for foetal abnormality. We conducted a secondary analysis of 37 qualitative interviews undertaken across the UK with 36 women and nine of their male partners (eight couples were interviewed together) who talked about diagnostic testing for foetal abnormality in 55 pregnancies. When describing their decisions, respondents referred to examples of knowledge gleaned from their own and other individuals' experiences as well as information based on biomedical or clinical-epidemiological research (usually about the probabilities of having a child affected by health problems or the probability of diagnostic tests causing miscarriage). Both forms of knowledge were employed in people's accounts to illustrate the legitimacy and internal coherence of decisions taken. The analysis demonstrates the personally idiosyncratic ways that people reflect on and incorporate different types of information to add meaning to abstract ideas about risk, to imagine the consequences for their own lives and to help them to make sense of the decisions they faced.     

Targeting the human malaria parasite Plasmodium falciparum: in vitro identification of a new antiplasmodial hit in 4-phenoxy-2-trichloromethylquinazoline series

From the promising results we previously obtained in quinazoline series and to complete the evaluation of the in vitro antiplasmodial activity of original 2-trichloromethylquinazolines, we synthesized new quinazolines possessing a variously substituted phenoxy group at position 4 through a simple and efficient two-step-synthesis approach. The studies of their activity toward the multi-resistant W2 Plasmodium falciparum strain and of their cytotoxicity on the human hepatocyte HepG2 cell line highlighted a hit compound (molecule 7) displaying a W2 IC₅₀ value of 1.1 μM and a HepG2 CC₅₀ value of 50 μM, comparable to chloroquine and doxycycline. Structure-activity- and toxicity relationships indicate that the trichloromethyl group plays a key role in the antiplasmodial activity of such chemical scaffold and also that the phenoxy group substitution as a direct influence on the molecules selectivity. Moreover, molecule 7 displays significant specific activity against the Plasmodium genus in comparison with Toxoplasma and does not show any mutagenic property at the Ames test.     

Drinking sucrose enhances quinpirole-induced yawning in rats

Food and drugs can activate brain dopamine systems and sensitivity to the effects of drugs acting on those systems is influenced by amount and content of food consumed. This study examined the effects of drinking sucrose on behavioral effects of the direct-acting dopamine receptor agonist quinpirole. Male Sprague-Dawley rats (n=6/group) had free access to water or 10% sucrose and quinpirole dose-response curves (yawning and hypothermia) were generated weekly for 8 weeks. Subsequently, all rats drank water for 8 weeks with quinpirole dose-response curves determined on weeks 9, 10, and 16. In rats drinking sucrose, the ascending (D3 receptor-mediated), but not descending (D2 receptor-mediated), limb of the yawning dose-response curve shifted leftward. The D3 receptor-selective antagonist PG01037 shifted the ascending limb of the dose-response curve to the right in all rats. When rats that previously drank sucrose drank water, their sensitivity to quinpirole did not return to normal. Quinpirole-induced hypothermia was not different between groups. These data show that drinking sucrose increases sensitivity to a dopamine D3, but not D2, receptor-mediated effect and that this change is long lasting. Dopamine receptors mediate the effects of many drugs and the actions of those drugs are likely impacted by dietary factors.     

Chronic benzodiazepine treatment does not alter interactions between positive GABA(A) modulators and flumazenil or pentylenetetrazole in monkeys

Benzodiazepines and neuroactive steroids are positive c-aminobutyric acid(A) (GABA(A)) modulators acting at distinct binding sites; during benzodiazepine treatment, tolerance develops to many behavioral effects of benzodiazepines, although cross tolerance typically does not develop to neuroactive steroids. To determine whether differential changes in binding sites contribute to these behavioral differences, interactions between GABA(A) modulators were studied in two groups of four monkeys: one otherwise untreated group discriminated 0.178 mg/kg of the benzodiazepine midazolam; the other received 5.6 mg/kg/day of diazepam and discriminated 0.1 mg/kg of flumazenil, which binds to benzodiazepine sites without modulating GABA(A) receptors. In untreated monkeys, flumazenil antagonized midazolam but not the neuroactive steroid pregnanolone, whereas pentylenetetrazole (a negative modulator acting at a third site) antagonized both positive modulators. In diazepam-treated monkeys, 0.1 mg/kg of flumazenil or 32 mg/kg of pentylenetetrazole produced flumazenil-lever responding, which was reversed by midazolam and pregnanolone. As the flumazenil dose increased, larger doses of midazolam, but not pregnanolone, were needed to reverse flumazenil-lever responding. When the pentylenetetrazole dose increased, larger doses of both positive modulators were needed. Thus, interactions between GABA(A) modulators were not different between diazepam-treated and untreated monkeys and do not reveal changes in binding sites that could account for reported differences between benzodiazepines and neuroactive steroids.     

Development of a Complex Parent-Metabolite Joint Population Pharmacokinetic Model

This study aimed to develop a joint population pharmacokinetic model for an antipsychotic agent in development (S33138) and its active metabolite (S35424) produced by reversible metabolism. Because such a model leads to identifiability problems and numerical difficulties, the model building was performed using the FOCE-I and the Stochastic Approximation Expectation Maximization (SAEM) estimation algorithms in NONMEM and MONOLIX, respectively. Four different structural models were compared based on Bayesian information criteria. Models were first written as ordinary differential equations systems and then in closed form (CF) to facilitate further analyses. The impact of polymorphisms on genes coding for the CYP2C19 and CYP2D6 enzymes, respectively involved in the parent drug and the metabolite elimination were investigated using permutation Wald test. The parent drug and metabolite plasma concentrations of 101 patients were analyzed on two occasions after 4 and 8 weeks of treatment at 1, 3, 6, and 24 h following daily oral administration. All configurations led to a two compartment model with back-transformation of the metabolite into the parent drug and a first-pass effect. The elimination clearance of the metabolite through other processes than back-transformation was decreased by 35% [9-53%] in CYP2D6 poor metabolizer. Permutation tests were performed to ensure the robustness of the analysis, using SAEM and CF. In conclusion, we developed a complex joint pharmacokinetic model adequately predicting the impact of CYP2D6 polymorphisms on the parent drug and its metabolite concentrations through the back-transformation mechanism.     

The discriminative stimulus effects of midazolam are resistant to modulation by morphine,amphetamine, dizocilpine,and γ-butyrolactone in rhesus monkeys

Rationale  

Although abuse of benzodiazepines alone is uncommon, it is high in polydrug abusers, including those who primarily use opioids or stimulants.     

Effects of serotonin (5-HT)1A and 5-HT2A receptor agonists on schedule-controlled responding in rats: drug combination studies

Rationale

Indirect-acting serotonin (5-HT) receptor agonists (e.g., selective 5-HT reuptake inhibitors [SSRI]) stimulate multiple 5-HT receptors, although the role of particular receptors as well as interaction(s) among different receptors in the therapeutic effects of SSRIs is not fully understood.

Objectives

Relatively few studies have systematically examined direct-acting agonists in combination. This study examined the 5-HT_1A receptor agonists 8-hydroxy-2-(di-n-propylamino) tetralin hydrochloride (8-OH-DPAT; 0.01?C10.0?mg/kg) and 3-chloro-4-fluorophenyl-4-fluoro-4-([(5-methyl-6-methylamino-pyridin-2-ylmethyl)-amino]-methyl)-piperidin-1-yl-methanone (F13714; 0.01?C1.0?mg/kg) and the 5-HT_2A receptor agonists 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM; 0.32?C10.0?mg/kg) and dipropyltryptamine (DPT; 1.0?C32.0?mg/kg), alone and in combination, in rats responding under a fixed ratio schedule of food presentation.

Results

When administered alone, each drug decreased the rate of responding in a dose-related manner with the potency order being F13714?>?8-OH-DPAT?>?DOM?>?DPT. WAY100635 (5-HT_1A receptor antagonist; 0.01?C0.1?mg/kg) attenuated the rate-decreasing effects of 8-OH-DPAT and F13714 while MDL100907 (5-HT_2A receptor antagonist; 0.01?C0.1?mg/kg) attenuated the rate-decreasing effects of DOM and DPT. Dose addition analysis showed that the interaction between 8-OH-DPAT and F13714, as well as the interaction between DOM and DPT, was additive. In contrast, the interaction between 8-OH-DPAT and DOM, as well as the interaction between F13714 and DOM, was infra-additive.

Conclusions

This study shows that for some dose combinations, agonist actions at one 5-HT receptor subtype attenuate agonist actions at another 5-HT receptor subtype; thus, the combined neuropharmacological actions and therapeutic effects of indirect-acting agonists are not likely to be adequately characterized by examining in isolation activity at particular 5-HT receptor subtypes.     

Influence of body weight and type of chow on the sensitivity of rats to the behavioral effects of the direct-acting dopamine-receptor agonist quinpirole

Rationale  

Amount and type of food can alter dopamine systems and sensitivity to drugs acting on those systems.     

Modeling Sleep Data for a New Drug in Development using Markov Mixed-Effects Models

Purpose  

To characterize the time-course of sleep in insomnia patients as well as placebo and concentration-effect relationships of two hypnotic compounds, PD 0200390 and zolpidem, using an accelerated model-building strategy based on mixed-effects Markov models.