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Biomedical subjects

O Schmidt

Publications and source records attributed to O Schmidt.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effects of fat feeding and energy level on plasma metabolites and hormones in Shetland ponies.

The aim of this study was to investigate the influence of a fat-supplemented diet compared with a carbohydrate diet on the lipid metabolism and the enteroinsular axis of Shetland ponies. The 'crossover' experiment was divided into two parts: in the first 10 weeks the diets comprised the correct number of calories according to requirements and in the following 10 weeks they were hypercaloric, in order to check the effect of a different energy content of the diets. Feeding the fat-enriched diet, independently of its energy content, led to a significant decrease in plasma triglycerides, associated with a mean 50% increase of plasma lipoprotein lipase activity. After oral glucose load the ponies on fat-enriched diets showed higher plasma glucose concentrations. Oral glucose administration after feeding the hypercaloric fat-enriched diet led to a 25-fold increase of plasma insulin levels. Glucose-dependent insulinotropic polypeptide plasma levels were increased in the animals on the fat-enriched diets. The results of this study suggest that fat feeding improves triglyceride clearance. However, the fat supplementation of the diet also led to impaired glucose tolerance. These results are important for a better understanding of the function of the enteroinsular axis. To investigate the influences of fat on lipid metabolism in relation to the aetiopathogenesis of equine hyperlipaemia further studies involving diseased animals are needed.

Animals↗
PubMed2001

Locoregional recurrence in patients with anastomotic leakage after anterior resection for rectal carcinoma.

OBJECTIVE: Anastomotic leakage is a serious complication after anterior resection for rectal carcinoma. It is controversial whether anastomotic leakage influences the rate of locoregional recurrence and therefore survival. PATIENTS AND METHODS: The data of 940 patients with invasive rectal carcinoma stage I-III treated by curative anterior resection from 1978 to 1996 at the Department of Surgery of the University of Erlangen were analysed. Patients who received neoadjuvant or adjuvant treatment were excluded as well as patients who died postoperatively. 89 out of 814 patients (10.9%) developed an anastomotic leakage after anterior resection. RESULTS: The rate of locoregional recurrence during the first five postoperative years of all patients was 13.6%. In patients with anastomotic leakage the rate of locoregional recurrence was 22.0%, significantly higher than in patients without anastomotic leakage which was 12.5%, (P=0.018). On multivariate Cox regression analysis anastomotic leakage was shown to be an independent risk factor for locoregional recurrence (relative risk: 1.7, CI 95%: 1.02-2.75, P=0.042). Also cancer-related survival was influenced significantly by anastomotic leakage in univariate analysis as well as in multivariate analysis (relative risk: 1.6, CI 95%: 1.1-2.2, P=0.017). CONCLUSION: Anastomotic leakage after anterior resection for rectal carcinoma is a risk factor for locoregional recurrence and decreases cancer-related survival.

Journal Article↗
PubMed2001

Unveiling extracellular inorganic phosphate signals from blood in human cardiac 31P NMR spectra.

31P NMR spectra of the human heart are usually contaminated by signals that originate from blood. The main blood signals are 2,3-diphosphoglycerate (2,3-DPG), which overlap and sometimes obscure the signal of myocardial inorganic phosphate used to calculate intracellular pH and to monitor metabolic changes in the heart. In this work we demonstrate, first, that even without proton decoupling the resolution of such spectra can be high enough to evaluate intracellular inorganic phosphate of myocardium in about 70% of the spectra and, second, that extracellular inorganic phosphate from blood contributes a signal in the chemical shift region of the 2-phosphate signal of 2,3-DPG.

2,3-Diphosphoglycerate↗
PubMed2000

Evidence for serine protease inhibitor activity in the ovarian calyx fluid of the endoparasitoid Venturia canescens.

Endoparasitic wasps are able to develop inside permissive host insects due to their ability to overcome or evade the host's immune system. In the present study, we provide experimental evidence that ovarian calyx fluid of the ichneumonid endoparasitoid Venturia canescens has the potential to alter host haemocyte spreading and inhibit host haemolymph melanisation due to the presence of a putative serine protease inhibitor (serpin) activity. The existance of a serpin-like activity in the calyx fluid is also supported by experiments where the synthetic protease inhibitor p-APMSF had effects on cellular and cell-free immune reactions similar to ovarian calyx fluid. In addition, based on proteolytic digestion patterns of a wasp egg surface protein, we predict an Arg-specific trypsin-like protease activity in the host haemolymph which is possibly affected by calyx fluid components as well. Our data suggest that ovarian calyx fluid, deposited into the host together with the parasitoid egg, contains serpin activity which might transiently inactivate host defence reactions until other means of protection are established on the egg surface.

Journal Article↗
PubMed2000

Animal and plant members of a gene family with similarity to alkaloid-synthesizing enzymes.

Here we describe novel members of a gene family which have similarity to strictosidine synthase (SS), one of the key enzymes in the production of monoterpene indole alkaloids. In addition to the first animal member of the family described previously (Drosophila hemomucin), a second Drosophila member has been identified, which appears to differ in subcellular distribution from hemomucin. In Arabidopsis, SS-like genes form a multigene family, compatible with a possible function as antifeedants and antibacterial compounds. In Caenorhabditis, two members have been identified and one member each in mouse and human. Interestingly, the human SS-like gene is strongly expressed in the brain, the very organ many of the indole alkaloids act upon.

Amino Acid Sequence↗
PubMed2000

Artifacts in CSI-measurements caused by the drift of the static magnetic field.

In chemical shift resolved spectroscopic imaging (CSI) temporal changes in the static magnetic field (drift) can lead to distortions of the phase encoding process. This can result in localization artifacts. The extent of the artifact depends on the size of the drift, the number of acquisitions, as well as on the combination of the size of the field of view and the number of phase encoding gradient steps. Furthermore, it is affected by the succession of the phase encoding gradients. Precautions are described which allow substantial minimization of the artifact.

Humans↗
PubMed2000

Chicken synucleins: cloning and expression in the developing embryo.

Synucleins comprise a family of small intracellular proteins that have recently attracted considerable attention because of their involvement in human diseases. Mutations of alpha-synuclein has been found in several families with hereditary early-onset Parkinson's disease and accumulation of this protein in characteristic cytoplasmic inclusions is a pathohistological hallmark of several neurodegenerative diseases that have been recently classified as 'alpha;-synucleinopathies' (reviewed in Brain Res. Bull. 50 (1999) 465; J. Neurosci. Res. 58 (1999) 120; Philos. Trans. R. Soc. Lond. Biol. Sci. 354 (1999) 1101; Brain Pathol. 9 (1999) 733). Aggregates of beta-synuclein and persyn (gamma-synuclein) also have been found in dystrophic neurites associated with Parkinson's and other neurodegenerative diseases (Proc. Natl. Acad. Sci. USA 96 (1999) 13450; and our unpublished observations). Moreover, persyn has been implicated in malignization of breast tumours (Cancer Res. 57 (1997) 759; Cancer Res. 59 (1999) 742; Hum. Mol. Genet. 7 (1998) 1417). All synucleins have distinct, although overlapping, patterns of expression in the embryonic, postnatal and adult mammalian nervous systems, suggesting important, although still not clear, biological functions in neuronal developing. Chicken embryo is a unique object for developmental studies that allows in vivo manipulations not always possible for mammalian embryos. Studies of synucleins expression in this model system could shed light on their functions in the developing nervous system. We cloned three chicken synucleins from the embryonic neural cDNA libraries and studied their expression in normal chicken embryonic tissues by Northern and in situ hybridization with specific probes. Our results demonstrate that primary structures and expression patterns of synucleins are similar in birds and mammals, suggesting that conserved function of synucleins is important for embryonic development of vertebrates.

Amino Acid Sequence↗
PubMed2000

Mutations in a new gene, encoding a zinc-finger protein, cause tricho-rhino-phalangeal syndrome type I.

Tricho-rhino-phalangeal syndrome type I (TRPS I, MIM 190350) is a malformation syndrome characterized by craniofacial and skeletal abnormalities and is inherited in an autosomal dominant manner. TRPS I patients have sparse scalp hair, a bulbous tip of the nose, a long flat philtrum, a thin upper vermilion border and protruding ears. Skeletal abnormalities include cone-shaped epiphyses at the phalanges, hip malformations and short stature. We assigned TRPS1 to human chromosome 8q24. It maps proximal of EXT1, which is affected in a subgroup of patients with multiple cartilaginous exostoses and deleted in all patients with TRPS type II (TRPS II, or Langer-Giedion syndrome, MIM 150230; ref.2-5). We have positionally cloned a gene that spans the chromosomal breakpoint of two patients with TRPS I and is deleted in five patients with TRPS I and an interstitial deletion. Northern-blot analyses revealed transcripts of 7 and 10.5 kb. TRPS1has seven exons and an ORF of 3,843 bp. The predicted protein sequence has two potential nuclear localization signals and an unusual combination of different zinc-finger motifs, including IKAROS-like and GATA-binding sequences. We identified six different nonsense mutations in ten unrelated patients. Our findings suggest that haploinsufficiency for this putative transcription factor causes TRPS I.

Blotting, Northern↗
PubMed2000

Comprehensive allelotype and genetic anaysis of 466 human nervous system tumors.

Brain tumors pose a particular challenge to molecular oncology. Many different tumor entities develop in the nervous system and some of them appear to follow distinct pathogenic routes. Molecular genetic alterations have increasingly been reported in nervous system neoplasms. However, a considerable number of affected genes remain to be identified. We present here a comprehensive allelotype analysis of 466 nervous system tumors based on loss of heterozygosity (LOH) studies with 129 microsatellite markers that span the genome. Specific alterations of the EGFR, CDK4, CDKN2A, TP53, DMBT1, NF2, and PTEN genes were analyzed in addition. Our data point to several novel genetic loci associated with brain tumor development, demonstrate relationships between molecular changes and histopathological features, and further expand the concept of molecular tumor variants in neuro-oncology. This catalogue may provide a valuable framework for future studies to delineate molecular pathways in many types of human central nervous system tumors.

Alleles↗
PubMed2000

[Volumetry of pleural effusion in multi-morbidity, postoperative patients of a surgical intensive care unit. Comparison of ultrasound diagnosis and thoracic bedside image].

Aim of this study was to evaluate the importance of chest ultrasound and chest x-ray for the indication of thoracic drainage of pleural effusions in patients of an operative intensive care unit. Between December 1996 and June 1997 21 patients were included in a prospective trial in the operative intensive care unit. 26 thoracic drainages were used to drain pleural effusions. In all patients chest radiography in supine position and chest ultrasound were performed to assess the need of pleural drainage. Pleural fluid measured radiologically was categorized into 3 groups: pleural fluid less than 500 ml, 500 to 1,000 ml or more than 1,000 ml. The amount of the pleural effusion was sonographically determined by a standardized formula. After complete drainage of the pleural space the real volume of the fluid was measured and compared with the estimated value. The real amount of the fluid was correctly determined by chest radiographs in 16 cases (62%) and by chest ultrasound in 18 patients (69%). Pleural effusions less than 600 ml sonographically correlated much better with the real amount of the fluid than pleural effusions above 600 ml. In 8 cases (31%) ultrasound provided an additional information for correct indication of drainage. Considering both x-ray of the chest in supine position and chest ultrasound the correct indication to drain the pleural effusion was achieved in 25 cases (96%). In this prospective trial we compared chest ultrasound and chest radiography and demonstrated that ultrasound is more suitable to determine the amount of pleural effusions than radiography. In case of clinical and radiological suspicion on pleural effusion demanding for drainage a chest ultrasound should be performed to avoid underestimation of pleural fluid.

Adult↗
PubMed1999

1,3-Diphosphacyclobutane-2,4-diyl-2-ylidenide: A Unique Carbene and Its Trimethylalane Complex.

A unique bonding situation is displayed by the lithium 1,3-diphosphacyclobutane-2,4-diyl-2-ylidenide 2 small middle dot[Li(thf)(n)](+) (Ar=2,4,6-tBu(3)C(6)H(2)) obtained by deprotonation of 1. According to ab initio calculations, the anion 2 can viewed as a cyclic bis(phosphanyl)carbene. Reaction with trimethylaluminum gives the complex 3 small middle dot[Li(thf)(4)](+), whose crystal structure is presented.

Journal Article↗
PubMed1999

Insect glycobiology: a lectin multigene family in Drosophila melanogaster.

Glycodeterminants play an important role in mediating cellular and cell-substrate interactions during development and immune-related reactions enabling an organism to distinguish self determinants from non-self or modified-self determinants. One of the hallmarks of sugar recognition molecules (lectins) is their wide range of binding activities and their organisation in multigene families. Here we describe a group of Drosophila genes that are possible members of the C-type lectin family.

Amino Acid Sequence↗
PubMed1999

The EIF3S3 gene encoding the p40 subunit of the translation initiation factor eIF3 has eight exons and maps to the Langer-Giedion syndrome chromosome region on 8q24, but is not the TRPS1 gene.

We have mapped the gene encoding the p40 subunit of the eukaryotic translation initiation factor eIF3 (EIF3S3) close to the distal border of the minimal critical region for tricho-rhino-phalangeal syndrome type I (TRPS I) on human chromosome 8q24. Because this location makes EIF3S3 a candidate for the TRPS1 gene, we have determined the genomic structure of the EIF3S3 gene and searched for gene deletions and mutations in patients with TRPS I. The gene has eight exons and is transcribed from telomere to centromere. No deletion could be detected in 32 unrelated patients with an apparently normal karyotype. Sequence analysis of all exons in 15 unrelated patients did not reveal any point mutation either. Our data exclude EIF3S3 as the TRPS1 gene.

Blotting, Northern↗
PubMed1999

Genes and chromosomal breakpoints in the Langer-Giedion syndrome region on human chromosome 8.

The tricho-rhino-phalangeal syndrome type II (TRPS II, or Langer-Giedion syndrome) is an example of contiguous gene syndromes, as it comprises the clinical features of two autosomal dominant diseases, TRPS I and a form of multiple cartilaginous exostoses caused by mutations in the EXT1 gene. We have constructed a contig of cosmid, lambda-phage, PAC, and YAC clones, which covers the entire TRPS I critical region. Using these clones we identified a novel submicroscopic deletion in a TRPS I patient and refined the proximal border of the minimal TRPS1 gene region by precisely mapping the inversion breakpoint of another patient. As a first step towards a complete inventory of genes in the Langer-Giedion syndrome chromosome region (LGCR) with the ultimate aim to identify the TRPS1 gene, we analyzed 23 human expressed sequence tags (ESTs) and four genes (EIF3S3, RAD21, OPG, CXIV) which had been assigned to human 8q24.1. Our analyses indicate that the LGCR is gene-poor, because none of the ESTs and genes map to the minimal TRPS1 gene region and only two of these genes, RAD21 and EIF3S3, are located within the shortest region of deletion overlap of TRPS II patients. Two genes, OPG and CXIV, which are deleted only in some patients with TRPS II may contribute to the clinical variability of this syndrome.

Child↗
PubMed1999

Is the surface of endoparasitic wasp eggs and larvae covered by a limited coagulation reaction?

Evidence is presented for the existence of a Venturia homologue of hemomucin, a surface mucin that was recently described in Drosophila. Venturia hemomucin is part of the mucinous layer on the egg and larval surface of the parasitoid. Venturia hemomucin forms a complex with lipophorin and other host hemolymph components, that is similar to a hemomucin-lipophorin complex which is part of the coagulation reaction. The possible formation of a specific layer against the host defence system is discussed for eggs and larvae that develop inside another insect.

Journal Article↗
PubMed1999

A maternal gene mutation correlates with an ovary phenotype in a parthenogenetic wasp population.

Endoparasitoid wasps rely on maternal protein secretions, including viruses and virus-like particles (VLPs), to overcome host defense reactions. In the ichneumonid Venturia canescens, VLPs are assembled in the nuclei of ovarian calyx gland cells, secreted into the lumen of the gland, and eventually transmitted into the host caterpillar together with the parasitoid egg. One of the genes coding for VLP proteins, termed VLP1, exists in two alleles producing two structurally different proteins. Here we describe the establishment and initial phenotypic characterisation of two parthenogenetic laboratory strains, which differ in VLP1 as well as in other genetic markers. A comparison of calyx tissues from the two strains revealed morphological differences that seem to affect egg movement from the ovarioles into the oviduct. The observed histological changes are correlated with differences in egg maturation and embryonic development causing a delay in larval hatching in one of the strains. Under conditions that favour superparasitism, the two strains differ in the number of offspring produced.

Amino Acid Sequence↗