Suicide attempts and the tryptophan hydroxylase gene

Tryptophan hydroxylase (TPH) is the rate-limiting enzyme of serotonin synthesis. In this case-control study, we investigated whether the TPH gene was a susceptibility factor for suicidal behavior. Seven polymorphisms spanning the entire gene were studied in a case-control study including 231 individuals who had attempted suicide and 281 controls. Significant associations were found between variants in introns 7, 8 and 9 (chi(2) = 11.2, df = 1, P< 0.0008 for the allele distribution; these loci are in complete linkage disequilibrium) and in the 3' noncoding region (chi(2) = 30.94, P = 0.0014) and suicide attempt. The association was strongest for subjects who had attempted suicide by violent means and who had a history of major depression. No significant association was observed between suicide attempts and polymorphisms in the promoter, intron 1 and intron 3. The results presented here, and those of previous studies, suggest that a genetic variant of the 3' part of the TPH gene may be a susceptibility factor for a phenotype combining suicidal behavior, mood disorder and impulsive aggression.     

Venous thromboembolism in cirrhosis: A review of the literature

Although hemorrhage has traditionally been regarded as the most significant hemostatic complication of liver disease, there is increasing recognition that hypercoagulability is a prominent aspect of cirrhosis. Identifying markers of coagulability and monitoring anticoagulation therapy in the setting of cirrhosis is problematic. The bleeding risk of venous thromboembolism (VTE) prophylaxis and treatment in patients with chronic liver disease is unclear and there are currently no recommendations to guide practice in this regard. In the present report, the mechanism of coagulation disturbance in chronic liver disease is reviewed with an examination of the evidence for an increased VTE risk in cirrhosis. Finally, the available evidence is assessed for prophylaxis and therapy of VTE in chronic liver disease, and the role it may play in decreasing clinical decompensation and improving survival.     

Polymorphism at VNTR Locus 3′ to the apolipoprotein B gene in a tunisian population: Difference from other ethnic groups

The Hypervariable Region (HVR) detected at the 3′ end of the apolipoprotein B (Apo B) locus has been the subject of numerous studies. As for many VNTR (variable number of tandem repeat), this locus is highly polymorphic and until now about 20 alleles have been described. The genotype distribution in all populations follows the Hardy-Weinberg predictions. A bimodal pattern of allele frequency distribution is apparent in all Caucasoid populations. We have analyzed the frequencies of different alleles in a Tunisian population (123 individuals) by the polymerase chain reaction technique and compared our results to those obtained in several ethnic groups. It appears that the distributions of the allele frequencies are very different: for Caucasoid populations, there are two peaks of frequencies for alleles with 36 and 48 repeats, but alleles of intermediate lengths are more frequent. Hixson et al. [(1993) Hum Genet 91:475–479] have shown a similar difference between black and white American populations. We found the same results in a black African group. Some of the repeat units of this HVR contain a Ssp I restriction site and digestion of the PCR products by this enzyme gives different patterns on gradient acrylamide gel [Desmarais et al., 1993, Nucleic Acids Res 21:2179–2184.] The DNA of African individuals (42) has been analyzed to discover the origin of this new allele. Preliminary results indicate that these particular alleles probably arose by introgression from the African population into the Tunisian one. ©1995 Wiley-Liss, Inc.     

Allelic heterogeneity of mediterranean myoclonus and the cystatin B gene

Mediterranean myoclonus is a progressive myoclonus epilepsy with autosomal recessive inheritance. Anothe form has been described in Finland, the so-called Baltic myoclonus. Mediterranean myoclonus and Baltic myoclonus are also known as Unverricht-Lundborg disease. Linkage analyses have shown that the genes for both these forms of myoclonus are closely linked to 21q22.3 DNA markers, suggesting that they are caused by mutations at the same locus (EPM1). Recently, two heterozygous mutations were found in the cystatin B gene in patients with Unverricht-Lundborg disease. We report recombinational and linkage disequilibrium mapping of EPM1, and cystatin B gene sequencing, in 14 consanguineous pedigrees with Mediterranean myoclonus. Linkage to 21q22.3 DNA markers was observed in all these families. Haplotype analysis suggests that a common mutation segregates within these pedigrees, and that this mutation is different from the common one responsible for the Finnish form of Unverricht-Lundborg disease. No mutation was found in the exons or splice junctions of the cystatin B gene in the 14 pedigrees.     

Emergence of sensory structures in the developing epidermis in sepia officinalis and other coleoid cephalopods

Embryonic cuttlefish can first respond to a variety of sensory stimuli during early development in the egg capsule. To examine the neural basis of this ability, we investigated the emergence of sensory structures within the developing epidermis. We show that the skin facing the outer environment (not the skin lining the mantle cavity, for example) is derived from embryonic domains expressing the Sepia officinalis ortholog of pax3/7, a gene involved in epidermis specification in vertebrates. On the head, they are confined to discrete brachial regions referred to as “arm pillars” that expand and cover Sof‐pax3/7‐negative head ectodermal tissues. As revealed by the expression of the S. officinalis ortholog of elav1, an early marker of neural differentiation, the olfactory organs first differentiate at about stage 16 within Sof‐pax3/7‐negative ectodermal regions before they are covered by the definitive Sof‐pax3/7‐positive outer epithelium. In contrast, the eight mechanosensory lateral lines running over the head surface and the numerous other putative sensory cells in the epidermis, differentiate in the Sof‐pax3/7‐positive tissues at stages ～24–25, after they have extended over the entire outer surfaces of the head and arms. Locations and morphologies of the various sensory cells in the olfactory organs and skin were examined using antibodies against acetylated tubulin during the development of S. officinalis and were compared with those in hatchlings of two other cephalopod species. The early differentiation of olfactory structures and the peculiar development of the epidermis with its sensory cells provide new perspectives for comparisons of developmental processes among molluscs. J. Comp. Neurol. 522:3004–3019, 2014. © 2014 Wiley Periodicals, Inc.     

DNA polymorphisms in linkage disequilibrium at the 3' end of the human APO AII gene: relationships with lipids, apolipoproteins and coronary heart disease

Two investigations were undertaken to analyze the 3' region of the apolipoprotein AII (Apo AII) gene in patients with myocardial infarction (MI) and controls. Previous studies have suggested that a MspI polymorphism in this gene may be associated with hypertriglyceridaemia, high levels of HDL cholesterol and Apo AII. To verify this hypothesis, the distribution of MspI genotypes and their possible associations with several plasma lipid variables were studied in 882 subjects (411 cases with MI and 471 controls) from the ECTIM study. There were no differences in genotype and allele frequencies between cases and controls, and no differences in lipid variable levels in controls carrying the less frequent MspI allele vs other controls. Using single-strand conformation polymorphism (SSCP) analysis, we detected a new polymorphism which caused by a C-to-T transition located in the third intron near the splice junction site (acceptor). This polymorphism modifies a Bst Nl restriction site. The ECTIM population was screened for this new marker, and no significant associations with MI and plasma lipid levels were found. Our results suggest that these two variants located in the coding region of the Apo AII gene are unlikely to contribute significantly to the level of plasma lipid variables and the risk of coronary heart disease (CHD) in the European population.     

Structure and function of alleles in the 3' end region of human apoB gene

ＯｂｊｅｃｔｉｖｅＴｏｓｔｕｄｙｔｈｅｓｔｒｕｃｔｕｒｅｏｆａｌｅｌｅｓｉｎｔｈｅ３’ｅｎｄｏｆｔｈｅａｐｏＢｇｅｎｅｉｎＨａｎ,ＭｏｎｇｏｌｉａｎａｎｄＴｉｂｅｔａｎｐｏｐｕｌａｔｉｏｎｓｉｎＣｈｉｎａａｓｗｅｌａｓｔｈｅｒｏｌｅｓｉｎｔｈｅｒｅｇ...     

BRD2 and TAP-1 genes and juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is a genetically determined common subtype of idiopathic generalized epilepsy. Linkage of JME to the chromosomal region 6p21.3 has been reported. An association has been previously observed between JME and the positional candidate, 6p21.3 linked, BRD2. Another candidate in this region is the TAP-1 gene encoding the Transporter Associated with Antigen Processing. The aim of the present study is to determine whether these two genes modulate the vulnerability to JME. While no difference was observed in the allele and genotype frequencies of BRD2 between JME and controls, an association was found between a TAP-1 haplotype and JME, suggesting that this gene may be another 6p21.3 linked vulnerability factor to JME.