Structure–activity study of N-((trans)-4-(2-(7-cyano-3,4-dihydroisoquinolin-2(1H)-yl)ethyl)cyclohexyl)-1H-indole-2-carboxamide (SB269652), a bitopic ligand that acts as a negative allosteric modulator of the dopamine D2 receptor

We recently demonstrated that SB269652 (1) engages one protomer of a dopamine D2 receptor (D2R) dimer in a bitopic mode to allosterically inhibit the binding of dopamine at the other protomer. Herein, we investigate structural deter- minants for allostery, focusing on modifications to three moieties within 1. We find that orthosteric “head” groups with small 7-substituents were important to maintain the limited negative cooperativity of analogues of 1, and replacement of the tetrahydroisoquinoline head group with other D2R “privileged structures” generated orthosteric antagonists. Additionally, replacement of the cyclohexylene linker with polymethylene chains conferred linker length dependency in allosteric pharma- cology. We validated the importance of the indolic NH as a hydrogen bond donor moiety for maintaining allostery. Replacement of the indole ring with azaindole conferred a 30-fold increase in affinity while maintaining negative cooperativity. Combined, these results provide novel SAR insight for bitopic ligands that act as negative allosteric modulators of the D2R

The importance of understanding individual differences in Down syndrome

In this article, we first present a summary of the general assumptions about Down syndrome (DS) still to be found in the literature. We go on to show how new research has modified these assumptions, pointing to a wide range of individual differences at every level of description. We argue that, in the context of significant increases in DS life expectancy, a focus on individual differences in trisomy 21 at all levels—genetic, cellular, neural, cognitive, behavioral, and environmental—constitutes one of the best approaches for understanding genotype/phenotype relations in DS and for exploring risk and protective factors for Alzheimer’s disease in this high-risk population

Safety after extended repeated use of ulipristal acetate for uterine fibroids

Objective: To assess long term safety of extended repeated 3-month courses of ulipristal acetate (UPA) 10 mg/day, for up to 8 courses, with focus on endometrial and laboratory safety parameters. Methods: This long-term, multi-center, open-label cohort, follow up study consisted of up to 8 consecutive 3-month courses of daily UPA 10 mg, each separated by a drug free period of 2 spontaneous menstrual bleeds. Sixty-four pre-menopausal women, with moderate to severe symptomatic uterine myoma(s) and heavy bleeding were enrolled and were studied for approximately 4 years. The main outcome measures were endometrial histology, laboratory parameters and general safety. Results: All data was reported in a descriptive manner with no formal statistical comparisons. In the 64 women, non-physiological changes (mostly cyst formation, epithelial and vascular changes) in endometrial histology at screening and after treatment courses 4 and 8 were observed in 18.0%, 21.4% and 16.3% of biopsies, respectively. After treatment cessation, such changes were observed in 9.1% of biopsies. All endometrial biopsies were benign after course 8. The median endometrial thickness was 7.0 mm, 10–18 days after the start of menses following treatment courses 5–8, compared to 9.0 mm at screening (before UPA treatment). No changes in the number and type of laboratory results outside the normal ranges were observed with the increasing treatment courses. In total, adverse events were reported in 10 (16%), 12 (19%), 8 (14%) and 5 (9%) subjects, during treatment courses 5, 6, 7 and 8, respectively of which the most frequent adverse events were headache and hot flush. Conclusion: The results of this study further support the safety profile of extended repeated 3 months treatment of symptomatic fibroids with ulipristal acetate 10 mg/day. Repeated UPA treatment courses did not result in any changes of concern in endometrial histology, endometrial thickness, or laboratory safety measures

Mitochondrial dysfunction in autism spectrum disorders: a systematic review and meta-analysis

A comprehensive literature search was performed to collate evidence of mitochondrial dysfunction in autism spectrum disorders (ASDs) with two primary objectives. First, features of mitochondrial dysfunction in the general population of children with ASD were identified. Second, characteristics of mitochondrial dysfunction in children with ASD and concomitant mitochondrial disease (MD) were compared with published literature of two general populations: ASD children without MD, and non-ASD children with MD. The prevalence of MD in the general population of ASD was 5.0% (95% confidence interval 3.2, 6.9%), much higher than found in the general population (∼0.01%). The prevalence of abnormal biomarker values of mitochondrial dysfunction was high in ASD, much higher than the prevalence of MD. Variances and mean values of many mitochondrial biomarkers (lactate, pyruvate, carnitine and ubiquinone) were significantly different between ASD and controls. Some markers correlated with ASD severity. Neuroimaging, in vitro and post-mortem brain studies were consistent with an elevated prevalence of mitochondrial dysfunction in ASD. Taken together, these findings suggest children with ASD have a spectrum of mitochondrial dysfunction of differing severity. Eighteen publications representing a total of 112 children with ASD and MD (ASD/MD) were identified. The prevalence of developmental regression (52%), seizures (41%), motor delay (51%), gastrointestinal abnormalities (74%), female gender (39%), and elevated lactate (78%) and pyruvate (45%) was significantly higher in ASD/MD compared with the general ASD population. The prevalence of many of these abnormalities was similar to the general population of children with MD, suggesting that ASD/MD represents a distinct subgroup of children with MD. Most ASD/MD cases (79%) were not associated with genetic abnormalities, raising the possibility of secondary mitochondrial dysfunction. Treatment studies for ASD/MD were limited, although improvements were noted in some studies with carnitine, co-enzyme Q10 and B-vitamins. Many studies suffered from limitations, including small sample sizes, referral or publication biases, and variability in protocols for selecting children for MD workup, collecting mitochondrial biomarkers and defining MD. Overall, this evidence supports the notion that mitochondrial dysfunction is associated with ASD. Additional studies are needed to further define the role of mitochondrial dysfunction in ASD

Applications of fluorescence and bioluminescence resonance energy transfer to drug discovery at G protein coupled receptors

The role of G protein coupled receptors (GPCRs) in numerous physiological processes that may be disrupted or modified in disease makes them key targets for the development of new therapeutic medicines. A wide variety of resonance energy transfer (RET) techniques such as fluorescence RET and bioluminescence RET have been developed in recent years to detect protein–protein interactions in living cells. Furthermore, these techniques are now being exploited to screen for novel compounds that activate or block GPCRs and to search for new, previously undiscovered signaling pathways activated by well-known pharmacologically classified drugs. The high resolution that can be achieved with these RET methods means that they are well suited to study both intramolecular conformational changes in response to ligand binding at the receptor level and intermolecular interactions involving protein translocation in subcellular compartments resulting from external stimuli. In this review we highlight the latest advances in these technologies to illustrate general principles

Individualized vaginal bleeding experience of women with uterine fibroids in the PEARL I randomized controlled trial comparing the effects of ulipristal acetate or placebo

RESEARCH QUESTION What is the individualized bleeding experience of women with fibroids and anaemia in a 3 month randomized placebo controlled trial (PEARL I) of the selective progesterone receptor modulator (SPRM), ulipristal acetate (UPA)?<p></p> SUMMARY ANSWER In contrast to continuing excessive regular menstruation in the placebo group, a majority of women treated with UPA (63.1% of those on 5 mg/day and 71.3% of those on 10 mg/day) experienced the rapid onset of amenorrhoea or minimal blood loss [pictorial blood loss assessment chart (PBAC) < 12]. The remainder experienced various patterns of bleeding and intensity of blood loss that are described for the first time, including an association of irregular bleeding on UPA with sub-mucous fibroids.<p></p> WHAT IS KNOWN ALREADY The majority experience on UPA is amenorrhoea but the bleeding experience of the others has not been characterized.<p></p> STUDY DESIGN, SIZE, DURATION A 13 week randomized controlled trial in women, eligible for surgery for uterine fibroids and anaemia, comparing placebo (n = 48), UPA 5 mg (n = 95) or UPA 10 mg (n = 94). The treatment aim was fibroid shrinkage and the primary definitions and outcomes are published elsewhere; here the secondary outcome measure of vaginal bleeding pattern is described.<p></p> PARTICIPANTS/MATERIALS, SETTING, METHODS Women, 18–50 years old, with fibroids and haemoglobin ≤10.2 g/dl, justifying surgery. At least one fibroid was 3–10 cm diameter and uterus ≤16 weeks pregnancy size. All used the daily PBAC methodology in a screening cycle (Ps) and throughout treatment, and for the 4 weeks preceding Week 26 and Week 38 in those who did not have surgery. An excessive menstruation is PBAC > 100. The bleeding patterns were characterized using the classification of Belsey, developed under auspices of WHO.<p></p> MAIN RESULTS AND THE ROLE OF CHANCE In the placebo group, all women had an excessive screening PBAC [median 376; interquartile range (IQR) 241–574]; 81.3% of them had regular menstrual bleeding and the intensity of bleeding remained similar, so that the median PBAC in the next three periods was 90, 92 and 93% of the screening value. Four of the 48 women had spontaneous improvement in bleeding and one developed amenorrhoea and elevation of gonadotrophins. In the placebo group, 22 women provided Week 26 and 21 women provided Week 38 PBAC data. The median Week 26 PBAC (312: IQR 102–524) and Week 38 PBAC (236; IQR 103–465) indicated ongoing excessive bleeding. In the UPA group, screening PBAC confirmed excessive bleeding (UPA 5 mg, median 358; IQR 232–621; UPA 10 mg, median 330; IQR 235–542). UPA was initiated from the start of a menstruation (P1) and no women had regular periods on treatment. Following P1 through the whole of the remaining 13 weeks of UPA treatment amenorrhoea or minimal loss (PBAC < 12 for whole phase) occurred in 63.1% (UPA 5 mg) or 71.3% (UPA 10 mg). The characterization of the individualized bleeding experience of the remaining women on 5 mg and 10 mg UPA, respectively, were infrequent bleeding in 17.9 and 12.8%; frequent or prolonged bleeding or both in 12.7 and 11.7% and irregular bleeding in 5.3 and 3.2%. In those with prolonged, frequent or irregular bleeding there was a high chance that sub-mucous fibroids were present (UPA 5 mg 100% and UPA 10 mg 78.6%) but no correlation with progesterone receptor modulator-associated endometrial changes.<p></p> LIMITATIONS, REASONS FOR CAUTION The follow-up PBAC data at Week 26 and Week 38 are only valid for women who did not have surgical intervention. These groups may not be representative of the groups at screening.<p></p> WIDER IMPLICATIONS OF THE FINDINGS This first detailed description of these SPRM bleeding patterns provides clinicians with an indication of potential responses in women using the SPRM UPA and provides an extended definition of bleeding in untreated women with excessive bleeding and fibroids.<p></p&gt