Multicenter,randomized, double‐blind,active comparator and placebo‐controlled trial of a corticotropin‐releasing factor receptor‐1 antagonist in generalized anxiety disorder

Background: Antagonism of corticotropin‐releasing factor (CRF) receptors has been hypothesized as a potential target for the development of novel anxiolytics. This study was designed to determine the safety and efficacy of pexacerfont, a selective CRF‐1 receptor antagonist, in the treatment of generalized anxiety disorder (GAD). Method: This was a multicenter, randomized, double‐blind, placebo‐controlled and active comparator trial. Two hundred and sixty patients were randomly assigned to pexacerfont 100 mg/day (after a 1 week loading dose of 300 mg/day), placebo or escitalopram 20 mg/day in a 2:2:1 ratio. The primary outcome was the mean change from baseline to end point (week 8) in the Hamilton Anxiety Scale total score. Results: Pexacerfont 100 mg/day did not separate from placebo on the primary outcome measure. The half‐powered active comparator arm, escitalopram 20 mg/day, demonstrated efficacy with significant separation from placebo at weeks 1, 2, 3, 6, and 8 (P<.02). Response rates for pexacerfont, placebo, and escitalopram were 42, 42, and 53%, respectively. Genetic and psychometric rating scale data was obtained in 175 randomized subjects. There was a significant association between a single nucleotide polymorphism (SNP) of the gene encoding plexin A2 (PLXNA2‐2016) with the HAM‐A psychic subscale score for the entire cohort at baseline (FDR‐adjusted P=.015). Conclusions: Pexacerfont did not demonstrate efficacy compared to placebo for the treatment of GAD. Whether these findings are generalizable to this class of agents remains to be determined. Our preliminary genetic finding of an association between a SNP for the gene encoding plexin A2 and an anxiety phenotype in this study merits further exploration. The trial was registered at clinicaltrials.gov (NCT00481325) before enrollment. Depression and Anxiety, 2010. © 2010 Wiley‐Liss, Inc.     

Development by environment interactions controlling tryptophan hydroxylase expression

Tryptophan hydroxylase is the rate-limiting enzyme in the biosynthesis of serotonin (5-hydroxytryptamine; 5-HT). Two isoforms of tryptophan hydroxylase, derived from different genes, tph1 and tph2, have been identified. The tph1 isoform is expressed in peripheral tissues, whereas tph2 is brain and neuron-specific. Recent studies suggest that tph2 expression and brain serotonin turnover are upregulated in depressed suicide patients, and drug-free depressed patients, respectively. Increased tph2 expression could result from genetic influences, early life developmental influences, adverse experience during adulthood, or interactions among these factors. Studies in rodents support the hypothesis that interactions between early life developmental influences and adverse experience during adulthood play an important role in determining tph2 expression. In this review, we highlight the evidence for the effects of adverse early life experience and stressful experience during adulthood on both tph1 and tph2 expression.     

Vascular effects of prostacyclin: does activation of PPARδ play a role?

Prostacyclin (PGI(2)) is a potent vasodilator that exerts multiple vasoprotective effects in the cardiovascular system. The effects of PGI(2) are mediated by activation of the cell membrane G-protein-coupled PGI(2) receptor (IP receptor). More recently, however, it has been suggested that PGI(2) might also serve as an endogenous ligand and activator of nuclear peroxisome proliferator-activated receptorδ (PPARδ). Consistent with this concept, studies designed to define pharmacological properties of stable PGI(2) analogs revealed that beneficial effects of these compounds appear to be mediated, in part, by activation of PPARδ. This review discusses emerging evidence regarding the contribution of PPARδ activation to vasoprotective and regenerative functions of PGI(2) and stable analogs of PGI(2).     

Muscarinic agonists and antagonists in schizophrenia: recent therapeutic advances and future directions

Existing therapies for schizophrenia have limited efficacy, and significant residual positive, negative, and cognitive symptoms remain in many individuals with the disorder even after treatment with the current arsenal of antipsychotic drugs. Preclinical and clinical data suggest that selective activation of the muscarinic cholinergic system may represent novel therapeutic mechanisms for the treatment of schizophrenia. The therapeutic relevance of earlier muscarinic agonists was limited by their lack of receptor selectivity and adverse event profile arising from activation of nontarget muscarinic receptors. Recent advances in developing compounds that are selective to muscarinic receptor subtypes or activate allosteric receptor sites offer tremendous promise for therapeutic targeting of specific muscarinic receptor subtypes in schizophrenia.     

Neonatal Screening for Inborn Errors of Metabolism Using Tandem Mass Spectrometry: Experience of the Pilot Study in Andhra Pradesh,India

Objective  

To estimate the prevalence of the Inborn Errors of Metabolism (IEM), evaluate biomarker distributions and determine benefits of screening for the inborn errors of metabolism in Andhra Pradesh, India, using Tandem Mass Spectrometry (MS/MS).     

Synchronous occurrence of a hemorrhagic hypothalamic hamartoma and a suprasellar teratoma

Hypothalamic hamartomas have been reported to coexist with lesions like Rathke's cleft cyst and arachnoid cysts in the suprasellar or temporo-sylvian regions. This is the first report in indexed literature describing its association with a suprasellar teratoma. A 7-year-old girl presented with long-standing precocious puberty and generalized tonic-clonic seizures and recent-onset raised intracranial pressure. MRI done prior to the onset of symptomatic raised intracranial pressure revealed 2 distinct lesions in the suprasellar region. One was a midline, pedunculated lesion arising from the hypothalamus, with evidence of an old bleed within it. A separate lesion, with a wide base near the tuberculum sellae and a posteriorly directed conical tip, was noted in an adjacent sagittal cut. CT scan done at the time of admission demonstrated a re-bleed in the suprasellar region with blood in the lateral and third ventricles and gross hydrocephalus. The child was taken up for a ventriculoperitoneal shunt followed by complete excision of the lesions. Histopathologic examination confirmed the pedunculated lesion to be a hypothalamic hamartoma with evidence of hemorrhage, and the other to be a mature teratoma. Postoperative MRI confirmed complete excision of both the lesions. The child reported regression of precocious puberty and remained seizure-free until the last follow-up 6 months after surgery. A hypothesis based on a dysontogenetic mechanism is discussed to explain the unusual occurrence of the dual, seemingly unrelated pathologies. Hemorrhage into the hamartoma was an added oddity in this case.