Hypophosphatasia: molecular testing of 19 prenatal cases and discussion about genetic counseling

OBJECTIVE: We studied hypophosphatasia (HP) mutations in 19 cases prenatally detected by ultrasonography without familial history of HP. We correlated the mutations with the reported ultrasound signs, and discussed genetic counseling with regard to the particular dominantly inherited prenatal benign form of HP. METHOD: The coding sequence of the tissue nonspecific alkaline phosphatase (TNSALP) gene was analyzed by DNA sequencing, and 3D modeling was used to locate the mutated amino acids with regard to the functional domains of TNSALP. RESULTS: Although reported ultrasound signs were heterogeneous, two mutated alleles were found in 18 of the 19 cases studied, indicating recessive transmission of the disease. Functional domains of TNSALP were affected by 74% of missense mutations. In all the cases, including one with only a heterozygous mutation, molecular, biological, and familial data do not corroborate the hypothesis of prenatal benign HP. The mutation c.1133A>T observed in the prenatal benign form of HP and common in USA was not found in this series. CONCLUSION: The results point out the prenatally detectable allelic heterogeneity of HP. The nature of the detected mutations and the evidence of recessive inheritance do not support these cases being affected with prenatal benign HP.     

Intradialytic hyperalimentation as adjuvant support in pregnant hemodialysis patients: case report and review of the literature

Pregnancy in chronic dialysis patients is unusual and associated with many complications. Infants are often born both prematurely and small for gestational age. We report a case of a 36-year-old diabetic hemodialysis patient G4P3 who had prolonged hyperemesis gravidarum, for whom intradialytic parenteral nutrition (IDPN) was started at week 14 and continued throughout her pregnancy. She delivered a 3.5-kg baby girl at the 36th week of gestation by cesarean section. We discuss the use of IDPN as adjunct therapy for pregnant dialysis patients.     

Fast Automatic Segmentation of White Matter Streamlines Based on a Multi-Subject Bundle Atlas

This paper presents an algorithm for fast segmentation of white matter bundles from massive dMRI tractography datasets using a multisubject atlas. We use a distance metric to compare streamlines in a subject dataset to labeled centroids in the atlas, and label them using a per-bundle configurable threshold. In order to reduce segmentation time, the algorithm first preprocesses the data using a simplified distance metric to rapidly discard candidate streamlines in multiple stages, while guaranteeing that no false negatives are produced. The smaller set of remaining streamlines is then segmented using the original metric, thus eliminating any false positives from the preprocessing stage. As a result, a single-thread implementation of the algorithm can segment a dataset of almost 9 million streamlines in less than 6 minutes. Moreover, parallel versions of our algorithm for multicore processors and graphics processing units further reduce the segmentation time to less than 22 seconds and to 5 seconds, respectively. This performance enables the use of the algorithm in truly interactive applications for visualization, analysis, and segmentation of large white matter tractography datasets.     

How to quantify iron in an aqueous or biological matrix: a technical note

Iron oxide (nano)particles are powerful contrast agents for MRI and tags for magnetic cellular labeling. The need for quantitative methods to evaluate the iron content of contrast media solutions and biological matrixes is thus obvious. Several convenient methods aiming at the quantification of iron from iron oxide nanoparticle‐containing samples are presented. Copyright © 2009 John Wiley & Sons, Ltd.     

Stimulation by antipsychotic agents of mitogen-activated protein kinase (MAPK) coupled to cloned,human (h)serotonin (5-HT)(1A) receptors

RATIONALE: There is evidence that serotonergic mechanisms contribute to the functional profiles of antipsychotic drugs, several of which display affinity for human (h)5-HT(1A) receptors. OBJECTIVE: Here, we compared the interaction of several antipsychotic agents at h5-HT(1A) receptors employing mitogen-activated protein kinase (MAPK), an intracellular marker. METHODS: The influence of antipsychotics on MAPK phosphorylation was quantified in Chinese hamster ovary (CHO) cells stably transfected with h5-HT(1A) receptors by use of a highly selective antibody. RESULTS: The novel antipsychotic agent, S16924, concentration-dependently (pEC(50), 8.10) stimulated the phosphorylation of MAPK. Its maximal effect (96%) was similar to that of the prototypical 5-HT(1A) agonist, (+)8-OH-DPAT (pEC(50), 8.54) (defined as 100%). The selective 5-HT(1A) receptor antagonist WAY100,635, which was inactive alone, abolished stimulation of MAPK by S16924 with a pK(b) of 9.66. This stimulatory influence of S16924 on MAPK was potently mimicked by the benzoisoxazole, antipsychotic ziprasidone (pEC(50), 7.25; 93%). The atypical antipsychotic clozapine also activated MAPK, albeit with lower potency and efficacy (pEC(50), 5.43 and 43%). These actions of ziprasidone and clozapine were also blocked by WAY100,635. Evaluated at a single, high concentration, several other antipsychotics stimulated MAPK phosphorylation with variable efficacy: quetiapine (75%), ocaperidone (74%), tiospirone (57%), olanzapine (54%) and risperidone (21%). In all cases, their actions were abolished by WAY100,635. In contrast, haloperidol, thioridazine and sertindole did not stimulate MAPK. CONCLUSIONS: Antipsychotics display contrasting efficacies in modulating MAPK phosphorylation at h5-HT(1A) receptors, ranging from high (e.g. S16924 and ziprasidone), via intermediate (e.g. clozapine) to low (e.g. haloperidol). Differential modulation of 5-HT(1A) receptor-coupled MAPK may contribute to their contrasting functional profiles.     

Constitutive activation of the neurotensin receptor 1 by mutation of Phe(358) in Helix seven

1. The neurotensin receptor 1, NTS1, is a G protein-coupled receptor with seven transmembrane domains (TM) that mediates most of the known effects of the neuropeptide. Our previous studies have pointed to extracellular loop 3 and adjacent TM7 as being potentially involved in agonist-induced activation of the NTS1. 2. Here we investigated residues in these domains that might be involved in transconformational activation of the rat NTS1. Single amino acid mutated receptors were expressed in COS cells and inositol phosphate (IP) and cyclic AMP productions were studied. 3. The F358A mutation in TM7 resulted in a time- and receptor concentration-dependent increase in spontaneous IP production. At expression levels of 12 pmol mg(-1), agonist-independent IP production was increased 10 fold over basal for the F358A mutant receptor whereas the wild type NTS1 exhibited virtually no spontaneous activity at expression levels of 7.5 pmol mg(-1). 4. Neurotensin remained agonist on the F358A mutant receptor with a maximal effect that amounted to greater than twice basal IP levels. SR 48692 was inverse agonist at the mutant receptor, reversing IP production almost back to the levels measured in wild type NTS1-transfected cells. 5. Cyclic AMP production was not constitutively activated with the F358A mutant receptor but was stimulated by neurotensin with the same concentration dependence as that observed with the wild type NTS1. 6. This is the first report, to our knowledge, of a constitutively active mutant of the NTS1. The data are consistent with TM7 being involved in the transconformational changes that lead to agonist-induced coupling of the NTS1 to Gq.     

Activation of KCNQ5 channels stably expressed in HEK293 cells by BMS-204352

The novel anti-ischemic compound, BMS-204352 ((3S)-(+)-(5-chloro-2-methoxyphenyl)-1,3-dihydro-3-fluoro-6-(trifluoromethyl)-2H-indol-2-one)), strongly activates the voltage-gated K+ channel KCNQ5 in a concentration-dependent manner with an EC50 of 2.4 microM. At 10 microM, BMS-204352 increased the steady state current at -30 mV by 12-fold, in contrast to the 2-fold increase observed for the other KCNQ channels [Schr?der et al., 2001]. Retigabine ((D-23129; N-(2-amino-4-(4-fluorobenzylamino)-phenyl) carbamic acid ethyl ester) induced a smaller, yet qualitatively similar effect on KCNQ5. Furthermore, BMS-204352 (10 microM) did not significantly shift the KCNQ5 activation curves (threshold and potential for half-activation, V1/2), as observed for the other KCNQ channels. In the presence of BMS-204352, the activation and deactivation kinetics of the KCNQ5 currents were slowed as the slow activation time constant increased up to 10-fold. The M-current blockers, linopirdine (DuP 996; 3,3-bis(4-pyridinylmethyl)-1-phenylindolin-2-one) and XE991 (10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone), inhibited the activation of the KCNQ5 channel induced by the BMS-204352. Thus, BMS-204352 appears to be an efficacious KCNQ channels activator, and the pharmacological properties of the compound on the KCNQ5 channel seems to be different from what has been obtained on the other KCNQ channels.