Variation in gene copy number and polymorphism of the human salivary amylase isoenzyme system in Caucasians

The polymorphic patterns of human salivary amylase of a large number of individuals of Caucasian origin were determined by using isoelectric focusing and polyacrylamide gel electrophoresis. Nine different salivary amylase protein variants were found; three of them are recorded for the first time and their heredity is shown. Some of the variants are encoded by haplotypes expressing three allozymes. Most variants display low frequencies. Analysis of the relative intensities of variant-specific isozyme bands, combined with segregation analysis, show that extensive quantitative variation is present in the population. The numbers of salivary amylase genes in some families showing quantitative variation at the protein level have been estimated by the polymerase chain reaction. We present evidence that quantitative variations in amylase protein patterns do not always reflect variations in gene copy number but that other mechanisms are also involved. © 1992 Springer-Verlag

Green function techniques in the treatment of quantum transport at the molecular scale

The theoretical investigation of charge (and spin) transport at nanometer length scales requires the use of advanced and powerful techniques able to deal with the dynamical properties of the relevant physical systems, to explicitly include out-of-equilibrium situations typical for electrical/heat transport as well as to take into account interaction effects in a systematic way. Equilibrium Green function techniques and their extension to non-equilibrium situations via the Keldysh formalism build one of the pillars of current state-of-the-art approaches to quantum transport which have been implemented in both model Hamiltonian formulations and first-principle methodologies. We offer a tutorial overview of the applications of Green functions to deal with some fundamental aspects of charge transport at the nanoscale, mainly focusing on applications to model Hamiltonian formulations.Comment: Tutorial review, LaTeX, 129 pages, 41 figures, 300 references, submitted to Springer series "Lecture Notes in Physics

Generation and molecular characterization of head and neck squamous cell lines of fanconi anemia patients

Patients with Fanconi anemia (FA) are prone to develop malignancies at an early age. Besides hematologic malignancies, squamous cell carcinomas in the anogenital region and head and neck are also frequently found in these patients. The aim of this study was to generate a panel of head and neck squamous cell carcinoma (HNSCC) cell lines and xenografts of FA HNSCC, and to characterize these cell lines in comparison with a panel of seven cell lines from patients with sporadic HNSCC. Analyses have been done on sensitivity to DNA cross-linking agents, loss of heterozygosity profile, TP53 mutations, TP53 polymorph isms and the presence of human papillomavirus. Four FA HNSCC cell lines were established. Sensitivity to DTNA cross-linking agents (cisplatin) in the FA HNSCC cell lines was on average 10 times higher as compared with the sporadic HNSCC cell lines. Human papillomavirus was not detected in any of the FA or sporadic cell lines. No differences were found in loss of heterozygosity pattern, TP53 mutation frequency and TP53 polymorphism between FA and sporadic HNSCC cell lines. This is the first report on the generation of squamous cell lines of FA patients. The FA HNSCC cell lines we have,generated may be utilized for future studies and might aid in the development of new preventive therapies for FA patients. The genetic characteristics of these cell lines suggest that FA HNSCC are not.,cry different from sporadic HNSCC, except for the sensitivity to cisplatin which is consistent with the known cellular FA phenotype

RNA Sequencing of Creatine Transporter (SLC6A8) Deficient Fibroblasts Reveals Impairment of the Extracellular Matrix

Creatine transporter (SLC6A8) deficiency is the most common cause of cerebral creatine syndromes, and is characterized by depletion of creatine in the brain. Manifestations of this X-linked disorder include intellectual disability, speech/language impairment, behavior abnormalities, and seizures. At the moment, no effective treatment is available. In order to investigate the molecular pathophysiology of this disorder, we performed RNA sequencing on fibroblasts derived from patients. The transcriptomes of fibroblast cells from eight unrelated individuals with SLC6A8 deficiency and three wild-type controls were sequenced. SLC6A8 mutations with different effects on the protein product resulted in different gene expression profiles. Differential gene expression analysis followed by gene ontology term enrichment analysis revealed that especially the expression of genes encoding components of the extracellular matrix and cytoskeleton are altered in SLC6A8 deficiency, such as collagens, keratins, integrins, and cadherins. This suggests an important novel role for creatine in the structural development and maintenance of cells. It is likely that the (extracellular) structure of brain cells is also impaired in SLC6A8-deficient patients, and future studies are necessary to confirm this and to reveal the true functions of creatine in the brain. © 2014 WILEY PERIODICALS, INC

Genotype impacts survival in Marfan syndrome

Item does not contain fulltextAIMS: The aorta in Marfan syndrome (MFS) patients is variably affected. We investigated the assumed genotype-effect on protein production as a risk factor for a severe aortic phenotype in adult MFS patients. METHODS AND RESULTS: We collected clinical and genetic data from all 570 adults with MFS who had been included in the Dutch CONgenital CORvitia registry since the start in 2001. Mean age was 36.5 +/- 13.5 years (51.2% male, 28.9% prior aortic surgery, 8.2% prior aortic dissection). Patients were prospectively followed for a mean duration of 8.2 +/- 3.1 years. Men had more frequently aortic surgery at baseline (38.0 vs. 19.4%, P < 0.001) and during follow-up (24.0 vs. 15.1%, P = 0.008) compared with women. After 10-year follow-up cumulative survival was 93.8% and dissection-free survival was 84.2%. We found a pathogenic FBN1 mutation in 357 patients, of whom 146 patients (40.9%) were positive for a mutation causing haploinsufficiency (reduced fibrillin-1 protein) and 211 (59.1%) for a mutation leading to a DN effect (abnormal fibrillin-1 protein). Corrected for age, sex, and previous aortic complications, patients with a haploinsufficient (HI) mutation had a 2.5-fold increased risk for cardiovascular death (hazard ratio, HR: 2.5, 95% CI: 1.0-6.1, P = 0.049), a 2.4-fold increased risk for the combined endpoint comprising death and dissection (HR: 2.4, 95% CI: 1.4-4.2, P < 0.001) and a 1.6-fold increased risk for any aortic complication compared with patients with a DN mutation (HR: 1.6, 95% CI 1.1-2.3, P = 0.014). CONCLUSION: Marfan syndrome patients with an HI mutation are at increased risk for cardiovascular death and aortic dissection compared with patients with a DN mutation

The parent-of-origin effect of 10q22 in pre-eclamptic females coincides with two regions clustered for genes with down-regulated expression in androgenetic placentas

By affected sib-pair linkage analysis of 24 families with pre-eclampsia, we confirm a susceptibility locus on chromosome 10q22.1 in Dutch females: a multipoint non-parametric linkage score of 3.6 near marker D10S1432 was obtained. Haplotype analysis showed a parent-of-origin effect: maximal allele sharing in the affected sibs was found for maternally derived alleles in all families, but not for the paternally derived alleles. As matrilineal inheritance suggests the presence of maternally expressed imprinted genes, while imprinting operates predominantly in (extra)embryonic tissues, all genes (n = 132) known on 10q22 between GATA121A08 and D10S580 were screened for seven sequence-related features associated with imprinting and subsequently tested for expression in first trimester placenta. Placental expression of genes selected in this way (n = 55) was compared with expression in androgenetic placentas of identical gestational age. Two regions on 10q22 were identified with developmentally co-repressed genes with non-random chromosomal distribution. Interestingly, these two clusters, near CTNNA3 and KCNMA1 and each containing five genes with down-regulated expression in androgenetic placentas, coincided with the regions with maximal maternal allele sharing seen in the pre-eclamptic sisters. Our linkage and expression data are compatible with the concept that pre-eclampsia involves maternally expressed imprinted genes that operate in the first trimester placenta