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T Maes

Publications and source records attributed to T Maes.

11 recordsLinked to original sources
PubMed2006

Role of tumour necrosis factor-alpha receptor p75 in cigarette smoke-induced pulmonary inflammation and emphysema.

Chronic obstructive pulmonary disease (COPD) is characterised by a local pulmonary inflammatory response to respiratory pollutants and by systemic inflammation. Tumour necrosis factor (TNF)-alpha has been implicated in systemic effects of COPD and operates by binding the p55 (R1) and p75 (R2) TNF-alpha receptors. To investigate the contribution of each TNF-alpha receptor in the pathogenesis of COPD, the present study examined the effects of chronic air or cigarette smoke (CS) exposure in TNF-alpha R1 knockout (KO) mice, TNF-alpha R2 KO mice and wild type (WT) mice. CS was found to significantly increase the protein levels of soluble TNF-alpha R1 (by four-fold) and TNF-alpha R2 (by 10-fold) in the bronchoalveolar lavage of WT mice. After 3 months, CS induced a prominent pulmonary inflammatory cell influx in WT and TNF-alpha R1 KO mice. In TNF-alpha R2 KO mice, CS-induced pulmonary inflammation was clearly attenuated. After 6 months, no emphysema was observed in CS-exposed TNF-alpha R2 KO mice in contrast to WT and TNF-alpha R1 KO mice. CS-exposed WT and TNF-alpha R1 KO mice failed to gain weight, whereas the body mass of TNF-alpha R2 KO mice was not affected. These current findings suggest that both tumour necrosis factor-alpha receptors contribute to the pathogenesis of chronic obstructive pulmonary disease, but tumour necrosis factor-alpha receptor-2 is the most active receptor in the development of inflammation, emphysema and systemic weight loss in this murine model of chronic obstructive pulmonary disease.

Animals↗
PubMed2006

Lysosome-associated membrane protein 1 (LAMP-1) in Alzheimer's disease.

Lysosome-associated membrane protein 1 (LAMP-1) is a glycoprotein highly expressed in lysosomal membranes. The present study was initiated to test LAMP-1 mRNA and protein levels in post mortem frontal cortex (area 8) of Alzheimer's disease (AD) stages I-IIA/B and stages V-VIC of Braak and Braak, compared with age-matched controls. TaqMan PCR assays and Western blots demonstrated upregulation of LAMP-1 mRNA and protein in the cerebral cortex in ADVC. In addition, immunohistochemical studies have shown increased LAMP-1 immunoreactivity in neurones, and in glial cells surrounding senile plaques, in AD cases. Interestingly, LAMP-1 immunoreactivity has little correlation with phosphorylated tau deposition and neurofibrillary tangles (NFTs), as neurones with NFTs were rarely LAMP-1 immunoreactive. In contrast, LAMP-1 expression was enhanced in neurones with granulovacuolar degeneration. Finally, LAMP-1 occurred in microglia and multinucleated giant cells in one AD case in whom amyloid burden was cleared following betaA-peptide immunization. These findings support the participation of lysosomes in betaA-amyloid and, probably, in hyperphosphorylated tau turnover in AD.

Aged↗
PubMed2005

Murine models of COPD.

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, that is not fully reversible, and that is associated with an abnormal inflammatory response of the airways and lungs to noxious particles and gases. The airflow limitation is caused by increased resistance of the small conducting airways and by decreased elastic recoil forces of the lung due to emphysematous destruction of the lung parenchyma. In vivo animal models can help to unravel the molecular and cellular mechanisms underlying the pathogenesis of COPD. Mice represent the most favored animal species with regard to the study of (both innate and adaptive) immune mechanisms, since they offer the opportunity to manipulate gene expression. Several experimental approaches are applied in order to mimic the different traits of COPD in these murine models. Firstly, the tracheal instillation of tissue-degrading enzymes induces emphysema-like lesions in the lung parenchyma, adding further proof to the protease-antiprotease imbalance hypothesis. Secondly, the inhalation of noxious stimuli, including tobacco smoke, sulfur dioxide, nitrogen dioxide, or oxidants such as ozone, may also lead to COPD-like lesions in mice, depending on concentration, duration of exposure and strainspecific genetic susceptibility. Thirdly, in transgenic mice, a specific gene is either overexpressed (non-specific or organ-specific) or selectively depleted (constitutively or conditionally). The study of these transgenic mice, either per se or in combination with the above mentioned experimental approaches (e.g. the inhalation of tobacco smoke), can offer valuable information on both the physiological function of the gene of interest as well as the pathophysiological mechanisms of diseases with complex traits such as COPD.

Animals↗
PubMed2001

Analysis by Transposon Display of the behavior of the dTph1 element family during ontogeny and inbreeding of Petunia hybrida.

Transposon Display is a high-resolution method that was used here to visualize simultaneously individual members of the dTph1 transposable element family of Petunia hybrida. The method provides a tool for accurate analyses of copy numbers and insertion frequencies, and a means to study the behavior of a family of elements as a whole. Somatic insertion events can be identified and insertion events in a cell of the L2 apical lineage can be distinguished unequivocally from those in a cell outside this lineage. In sublines of the high-copy-number line W137, an average insertion rate equivalent to transposition of 10% of the total number of element copies in each generation was measured, copy number increases of over 20% in four generations were recorded, and element position turnover was analyzed. Insertion events are detected essentially randomly both in time and space. The general applicability of the technique for the analysis of the transpositional behavior of element systems is discussed.

Cell Differentiation↗
PubMed2001

The att locus of Rhodococcus fascians strain D188 is essential for full virulence on tobacco through the production of an autoregulatory compound.

The ability of Rhodococcus fascians strain D188 to provoke leafy gall formation on a variety of plant species is correlated with the linear plasmid pFiD188, on which different pathogenicity loci were identified. The att locus affects the severity of symptom development on tobacco, whereas the fas locus is essential for virulence. To gain insight into the function of the att locus, sequence and expression analyses were performed. The att locus contains nine open reading frames homologous to arginine and beta-lactam biosynthetic genes. att gene expression is transcriptionally induced by leafy gall extracts, but not by extracts of uninfected plants, and depends on the attR gene that encodes a LysR-type transcriptional regulator. The att locus proves to be essential for the formation of inducing factors (IFs) that are present in gall extracts. Because the induction of the fas locus also requires the presence of IFs in gall extracts, the att locus is proposed to play an important role in regulating the expression of the virulence loci of R. fascians.

Bacterial Proteins↗
PubMed2001

Petunia Ap2-like genes and their role in flower and seed development.

We have isolated three Apetala2 (Ap2)-like genes from petunia and studied their expression patterns by in situ hybridization. PhAp2A has a high sequence similarity to the A function gene Ap2 from Arabidopsis and a similar expression pattern during flower development, suggesting that they are cognate orthologs. PhAp2B and PhAp2C encode for AP2-like proteins that belong to a different subgroup of the AP2 family of transcription factors and exhibit divergent, nearly complementary expression patterns during flower development compared with PhAp2A. In contrast, all three PhAp2 genes are strongly expressed in endosperm. The phenotype of the petunia A-type mutant blind cannot be attributed to mutations in the petunia Ap2 homologs identified in this study, and reverse genetics strategies applied to identify phap2a mutants indicate that PhAp2A might not be essential for normal perianth development in petunia. Nevertheless, we show that PhAp2A is capable of restoring the homeotic transformations observed in flowers and seed of the ap2-1 mutant of Arabidopsis. Although the interspecific complementation proves that PhAp2A encodes a genuine Ap2 ortholog from petunia, additional factors may be involved in the control of perianth identity in this species.

Amino Acid Sequence↗
PubMed1999

The inflorescence architecture of Petunia hybrida is modified by the Arabidopsis thaliana Ap2 gene.

We have introduced the Apetala2 (Ap2) gene of Arabidopsis thaliana into Petunia hybrida. Four out of 10 Ap2 transgenic plants flowered and exhibited an altered inflorescence architecture. Internode elongation suggests that the transition from the vegetative to the inflorescence phase does occur, although flower formation is delayed and the cymose branching pattern is not established. Instead, the inflorescence continues to produce bracts and eventually terminates in an aberrant flower with an excess of floral organs. New inflorescence branches then develop from the axillary meristems of the bracts, repeating the formation of a number of bracts before conversion into a terminal, aberrant flower. These results indicate that the Ap2 gene plays a role in the determination of inflorescence meristem identity, but not as a typical A-like function, adding to the existing doubt about the general role of Ap2 gene(s) in floral development.

Arabidopsis↗
PubMed1999

Plant tagnology.

Transposable elements have been used as an effective mutagen and as a tool to clone tagged genes. Insertion of a transposable element into a gene can lead to loss- or gain-of-function, changes in expression pattern, or can have no effect on gene function at all, depending on whether the insertion took place in coding or non-coding regions of the gene. Cloning transposable elements from different plant species has made them available as a tool for the isolation of tagged genes using homologous or heterologous tagging strategies. Based on these transposons, new elements have been engineered bearing reporter genes that can be used for expression analysis of the tagged gene, or resistance genes that can be used to select for knockout insertions. While many genes have been cloned using transposon tagging following traditional forward genetics strategies, gene cloning has ceased to be the rate-limiting step in the process of determining sequence-function relations in several important plant model species. Large-scale insertion mutagenesis and identification of insertion sites following a reverse genetics strategy appears to be the best method for unravelling the biological role of the thousands of genes with unknown functions identified by genome or expressed sequence tag (EST) sequencing projects. Here we review the progress in forward tagging technologies and discuss reverse genetics strategies and their applications in different model species.

Journal Article↗
PubMed1995

Targeted gene inactivation in petunia by PCR-based selection of transposon insertion mutants.

Establishment of loss-of-function phenotypes is often a key step in determining the biological function of a gene. We describe a procedure to obtain mutant petunia plants in which a specific gene with known sequence is inactivated by the transposable element dTph1. Leaves are collected from batches of 1000 plants with highly active dTph1 elements, pooled according to a three-dimensional matrix, and screened by PCR using a transposon- and a gene-specific primer. In this way individual plants with a dTph1 insertion can be identified by analysis of about 30 PCRs. We found insertion alleles for various genes at a frequency of about 1 in 1000 plants. The plant population can be preserved by selfing all the plants, so that it can be screened for insertions in many genes over a prolonged period.

Alleles↗
PubMedDate not supplied

Ultrafiltration controller failing: a case report.

The development of ultrafiltration controllers has been a major technical progress in haemodialysis. We report the failure of such a controller where the alarm failed to actuate, resulting in a patient weight gain of 3.1 kg over a full dialysis session, instead of a programmed 4.5 kg weight loss; fortunately, the patient recovered completely. Thus the question arises whether such failures may be prevented. In addition, the need for uninterrupted vigilance in haemodialysis monitoring is stressed.

Aged↗