Cognitive Impairment Among Tunisian Bipolar Patients: a Case-Control Study

Psychiatric Quarterly - Studies exploring the cognitive performance of bipolar patients have mainly been conducted in Western countries. To our knowledge, no surveys have been reported to date in...     

Structure properties and dielectric relaxation of Ca0.1Na0.9Ti0.1Nb0.9O3 ceramic

In this paper, the synthesis of Ca_0.1Na_0.9Ti_0.1Nb_0.9O₃ (CNTN) ceramic by a solid-state reaction method is reported. The results of Rietveld refinement of X-ray diffraction (XRD) patterns at room temperature showed a pure tetragonal perovskite (P4mm space group). Raman spectroscopy analysis, ranging from of 50 to 1000 cm⁻¹, at room temperature, validates the results of XRD. The dielectric properties was studied by complex impedance spectroscopy examined in broad frequency range, 100 Hz to 200 kHz, at different temperatures. The dielectric permittivity for our CNTN compound confirms the typical relaxor behavior. The investigation of the diffuseness of the transition was conducted by fitting the experimental data with modified Curie–Weiss law; Gaussian distribution and Power law confirm the presence of a short-range association between the polar nanoregions (PNRs). The obtained values of the diffuseness coefficient are of the order 1.6, which corresponds to the diffuse phase transition (DPT) ascribed to the existence of various states of polarization, thus various relaxation times in different regions. The value of diffuseness is of the order 85 and the degree of relaxor (ΔT_cm = 65 K) is interesting as far as microelectric applications are concerned. Moreover, based on the frequency dependence of temperature at dielectric maxima using Vogel–Fulcher relationship, a strong evidence for a static freezing temperature with regards to thermally-activated polarization fluctuations was found.

In this paper, the synthesis of Ca_0.1Na_0.9Ti_0.1Nb_0.9O₃ (CNTN) ceramic by a solid-state reaction is reported. The results of Rietveld refinement of X-ray diffraction patterns at room temperature showed a pure tetragonal perovskite (P4mm space group).     

West syndrome associated with Down syndrome: Case report and literature review

West syndrome is the most frequent cause of epilepsy in Down syndrome. West syndrome is often associated with poor long-term prognosis in most of children. We report a girl with West syndrome associated with Down syndrome which occurred at 8 months of age for repetitive flexor spasms and electroencephalography (EEG) showed hypsarrhythmia. She had Down syndrome facies, microcephaly, psychomotor development delay and axial hypotonia. Computed tomography of the brain was normal. Her karyotype was 47, XX, +21. Phenobarbital therapy was immediately effective with good clinical control of seizures, while the EEG monitored after one month was unchanged. At 2 years of age, the patient had hypertonic status epilepticus following a lung infection. The EEG showed a persistence of hypsarrhythmia. Sodium valproate and hydrocortisone therapy was effective with good seizure control but her psychomotor development was severely impaired. After a follow-up of 7 years, the patient presents growth retardation, microcephaly, severe psychomotor development delay, generalized hypotonia and tetraparesis. Knowledge of West syndrome in Down syndrome allows the early detection and prompt management of this neurological complication in order to optimize psychomotor development and improve the quality of life of these children.     

Familial form of typical childhood absence epilepsy in a consanguineous context

Causative genes for childhood absence epilepsy (CAE) are unknown partly because families are small or phenotypically heterogeneous. In five consanguineous Tunisian families with at least two sibs with CAE, 14 patients fulfilled the diagnostic criteria for CAE (Epilepsia 1989;30:389–399). Linkage analyses or direct sequencing excluded CACNG2, CACNA1A, CACNB4, and CACNA2D2, orthologs of genes responsible for autosomal recessive (AR) absence seizures in mice. These families will help identify (a) gene(s) responsible for CAE.     

Re-assigning the DFNB33 locus to chromosome 10p11.23-q21.1

Homozygosity mapping is a powerful resource for mapping and identifying loci and genes responsible for autosomal recessive disorders. Nevertheless, it could result in the identification of several homozygous regions unrelated to the disease locus or non-informative regions. Previously, a genome-wide screen in a large consanguineous Jordanian family allowed us to assign the DFNB33 locus to chromosome 9q34.3. Sequencing of 23 candidate genes showed 11 SNPs in a heterozygous state in affected individuals. These results ruled out the candidate region on chromosome 9. Using additional markers, we were able to restrict the disease locus to an approximately 14 cM region at chromosome 10, located between markers D10S193 and D10S1784. A maximum LOD score of 3.99 was obtained with two markers, D10S199 and D10S220. The screening of two candidate genes, CX40.1 and FXYD4, failed to reveal any disease-causing mutations.     

Tyrosine phosphorylation / dephosphorylation balance is involved in thrombin-evoked microtubular reorganisation in human platelets

We have investigated the intracellular mechanisms involved in microtubular remodelling by thrombin and its possible involvement in platelet aggregation and secretion. Platelet stimulation with thrombin induces a time- and concentration-dependent regulation of the microtubular content, which was found to be maximally effective at the concentration 0.1 U/ml. Thrombin (0.1 U/ml) evoked an initial decrease in the microtubule content detectable at 5 seconds (sec) and reached a minimum 10 sec after stimulation. The microtubular content then increased, exceeding basal levels again approximately 30 sec after stimulation. Inhibition of tyrosine phosphatases using vanadate abolished thrombin-induced microtubular depolymerisation while inhibition of tyrosine kinases by methyl-2,5-dihydroxycinnamate prevented microtubule polymerisation. Thrombin activates the cytosolic Bruton's tyrosine kinase (Btk) and Src proteins. Inhibition of Btk or Src by LFM-A13 or PP1, respectively, abolished thrombin-induced microtubular polymerisation, while maintaining intact its ability to induce initial depolymerisation. Microtubular disruption by colchicine significantly reduced thrombin-induced platelet aggregation and ATP secretion. Similar results were observed after inhibition of microtubular disassembly by paclitaxel. These findings indicate that thrombin induces microtubular remodelling by modifying the balance between protein tyrosine phosphorylation and dephosphorylation. The former seems to be required for microtubular polymerisation, while tyrosine dephosphorylation is required for microtubular depolymerisation. Both, initial microtubular disassembly and subsequent polymerisation are required for thrombin-induced platelet aggregation and secretion in human platelets.     

Are there racial differences in attitudes toward hospice care? A study of hospice-eligible patients at the Visiting Nurse Service of New York

Research on African American and white attitudes, perceptions, and knowledge of hospice care has focused predominantly on patients and providers in institutions and community-based care settings. Little is known about patients receiving home health services, despite growing trends toward noninstitutional care in the United States. This study of home health clients who are eligible for hospice, but not currently receiving it, found few differences between racial groups with regard to attitudes about end-of-life care. An alarming proportion of African American and white home health clients held erroneous ideas about hospice care and had not discussed this option with their providers. These findings suggest that increased referrals to home-based hospice care among home health clients depend on the availability and professional dissemination of accurate, spiritually sensitive information.