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Biomedical subjects

A Pohl

Publications and source records attributed to A Pohl.

At least 19 recordsLinked to original sources
PubMed2006

The UCSC genome browser database: update 2007.

The University of California, Santa Cruz Genome Browser Database contains, as of September 2006, sequence and annotation data for the genomes of 13 vertebrate and 19 invertebrate species. The Genome Browser displays a wide variety of annotations at all scales from the single nucleotide level up to a full chromosome and includes assembly data, genes and gene predictions, mRNA and EST alignments, and comparative genomics, regulation, expression and variation data. The database is optimized for fast interactive performance with web tools that provide powerful visualization and querying capabilities for mining the data. In the past year, 22 new assemblies and several new sets of human variation annotation have been released. New features include VisiGene, a fully integrated in situ hybridization image browser; phyloGif, for drawing evolutionary tree diagrams; a redesigned Custom Track feature; an expanded SNP annotation track; and many new display options. The Genome Browser, other tools, downloadable data files and links to documentation and other information can be found at http://genome.ucsc.edu/.

Animals↗
PubMed2006

The UCSC Genome Browser Database: update 2006.

The University of California Santa Cruz Genome Browser Database (GBD) contains sequence and annotation data for the genomes of about a dozen vertebrate species and several major model organisms. Genome annotations typically include assembly data, sequence composition, genes and gene predictions, mRNA and expressed sequence tag evidence, comparative genomics, regulation, expression and variation data. The database is optimized to support fast interactive performance with web tools that provide powerful visualization and querying capabilities for mining the data. The Genome Browser displays a wide variety of annotations at all scales from single nucleotide level up to a full chromosome. The Table Browser provides direct access to the database tables and sequence data, enabling complex queries on genome-wide datasets. The Proteome Browser graphically displays protein properties. The Gene Sorter allows filtering and comparison of genes by several metrics including expression data and several gene properties. BLAT and In Silico PCR search for sequences in entire genomes in seconds. These tools are highly integrated and provide many hyperlinks to other databases and websites. The GBD, browsing tools, downloadable data files and links to documentation and other information can be found at http://genome.ucsc.edu/.

Amino Acid Sequence↗
PubMed2006

Opening and closure characteristics of different types of stented biological valves.

BACKGROUND: In an increasingly senescent population stented biological valves have regained renewed popularity because of the absence of anticoagulation, while the stented design allows for safe and easier implantation. Constructed bovine pericardial valves as well as valves with porcine cusps are used, both of which exhibit good clinical results although degeneration still appears. While clinical hemodynamic studies did not show particular differences between both valves types, the opening and closure behavior of native cusps and artificially constructed pericardial leaflets is different. It is unclear whether these phenomena account for differences in load and stress which may influence onset and course of degeneration. MATERIAL AND METHODS: Edwards Perimount (EP) and Medtronic Mosaic (MM) heart valves with diameters of 21 mm, 23 mm, and 25 mm were investigated in a pulse duplicator. Movements of the valves were visualized with a high-speed camera (1000 frames/sec). Mean transvalvular gradient (mm Hg), dissipated power (mW), and power transfer by stretching (mW), mean orifice area (mm2), opening time (ms), and closure time (ms) were analyzed in a range of cardiac outputs from 1.4 l/min to 6.3 l/min and 70 beats per minute. RESULTS: Closure times were generally longer than opening times for both valve types. Opening time of EP valves was longer than opening time of the MM valves of the same size (EP23: 31.2 +/- 2.5 ms; MM23: 12.7 +/- 0.1 ms). With respect to closure times, however, there were no marked differences between all valves (EP23: 69.3 +/- 2.0 ms; MM23: 63.2 +/- 6.3 ms). Smaller sized Perimount valves exhibited lower mean transvalvular gradients than Mosaic valves of the same size (EP23: 7.21 +/- 0.07 mm Hg; MM23: 10.5 +/- 0.15 mm Hg). In larger sizes these differences diminished. Power transfer to the valve's structures was significantly enhanced in EP valves (EP23: 134 +/- 1.3 mW; MM23: 64 +/- 0.9 mW). CONCLUSIONS: While valves with constructed pericardium showed lower mean transvalvular gradients, particularly in the smaller sizes, this valve type exhibited alterations of movement performance in contrast to porcine valves. It can be speculated that constant power transfer to the valve's structures may result in an earlier degeneration because of the impact of the increased load and stress on the suspension apparatus of the constructed pericardial leaflets.

Animals↗
PubMed2003

Ex-situ conservation of Black poplar in Europe: genetic diversity in nine gene bank collections and their value for nature development.

Populus nigra L. is a pioneer tree species of riparian ecosystems that is threatened with extinction because of the loss of its natural habitat. To evaluate the existing genetic diversity of P. nigra within ex-situ collections, we analyzed 675 P. nigra L. accessions from nine European gene banks with three amplified fragment length polymorphism (AFLP) and five microsatellite [or simple sequence repeat (SSR)] primer combinations, and 11 isozyme systems. With isozyme analysis, hybrids could be detected, and only 3% were found in the gene bank collection. AFLP and SSR analyses revealed effectively that 26% of the accessions were duplicated and that the level of clonal duplication varied from 0% in the French gene bank collection up to 78% in the Belgian gene bank collection. SSR analysis was preferred because AFLP was technically more demanding and more prone to scoring errors. To assess the genetic diversity, we grouped material from the gene banks according to topography of the location from which the accessions were originally collected (river system or regions separated by mountains). Genetic diversity was expressed in terms of the following parameters: percentage of polymorphic loci, observed and effective number of alleles, and Nei's expected heterozygosity or gene diversity (for AFLP). Genetic diversity varied from region to region and depended, to some extent, on the marker system used. The most unique alleles were identified in the Danube region (Austria), the Rhône region (France), Italy, the Rijn region (The Netherlands), and the Ebro region (Spain). In general, the diversity was largest in the material collected from the regions in Southern Europe. Dendrograms and principal component analysis resulted in a clustering according to topography. Material from the same river systems, but from different countries, clustered together. The genetic differentiation among the regions (F(st)/G(st)) was moderate.

Cluster Analysis↗
PubMed2003

Congenital atresia of the portal vein and extrahepatic portocaval shunt associated with benign neonatal hemangiomatosis, congenital adrenal hyperplasia, and atrial septal defect.

A rare case of congenital atresia of the portal vein and ductus venosus, extrahepatic portocaval shunt, benign neonatal hemangiomatosis, congenital adrenal hyperplasia, and an atrial septal defect is reported. Twenty-two cases of congenital extrahepatic end-to-side shunts have been described before. Although additional anomalies are common in this type of shunt, hemangiomatosis has been described only once. Adrenal hyperplasia has never been reported in this anomaly.

Abnormalities, Multiple↗
PubMed2003

Body mass index influences plasma concentration of neuropeptide Y in healthy female volunteers: a pilot study.

Neuropeptide Y (NPY) was measured in plasma obtained from healthy female volunteers twice in the natural menstrual cycle or the hormonal cycle caused by oral contraceptives about 2 weeks apart. The ratio between the NPY plasma concentration in the second sample and the first sample was influenced negatively by body mass index (BMI). There were no differences in NPY plasma concentrations on comparing the first and second samples. Age and the use or non-use of oral contraceptives did not exert any influence. BMI might be a confounding factor when determining NPY in the plasma of healthy women.

Adult↗
PubMed2001

Acute and subacute stent occlusion; risk-reduction by ionic contrast media.

AIMS: Current data concerning the influence of X-ray contrast media on the incidence of thrombotic complications in interventional cardiology are controversial. The effect of ionic contrast media on acute (< or =72 h) and subacute (< or =30 days) stent thrombosis has not been investigated. METHODS: Three thousand, nine hundred and ninety consecutive patients underwent coronary stent placement. Group I (n=1808) received non-ionic contrast media while group II (n=2182) was given the ionic Ioxaglate. All patients were treated with a standard regimen of aspirin and ticlopidine for 4 weeks post intervention. RESULTS: Both acute and subacute stent occlusion occurred more frequently in patients receiving non-ionic contrast media compared to ionic contrast media (acute stent occlusion: 1.3% in group I vs 0.3% in group II, P=0.001; subacute stent occlusion: 2.4% in group I vs 0.7% in group II, P=0.001). The incidence of the combined clinical end-point of coronary artery bypass grafting, target lesion revascularization, and overall mortality within 12 months was significantly reduced by the use of Ioxaglate (22.9% vs 16.3%, P=0.001). CONCLUSIONS: Based upon these data, we recommend the use of Ioxaglate in coronary interventions when stent placement is anticipated.

Acute Disease↗
PubMed2001

Serum aminotransferase levels and platelet counts as predictors of degree of fibrosis in chronic hepatitis C virus infection.

OBJECTIVE: In patients with chronic hepatitis C virus (HCV) infection, liver fibrosis stage is a prognostic factor for therapy outcome. So far, a liver biopsy is necessary to determine disease stage accurately. We sought to develop a simple, noninvasive method of accurately predicting the degree of liver fibrosis in chronic HCV infection. METHODS: We retrospectively studied 211 consecutive patients with chronic HCV, who received a liver biopsy at the Liver Center of the University of California, San Diego. A total of 58 of these patients had a positive history of alcohol abuse, and we analyzed them separately in a sensitivity analysis. AST/ALT ratio and platelet counts were determined in all patients. Fibrosis was staged using the METAVIR score. RESULTS: Both AST/ALT ratio and platelet counts correlated significantly with the disease stage (r = 0.190, p = 0.006, and r = -0.543, p < 0.00, respectively). In a sensitivity analysis, there was no correlation between AST/ALT ratio and disease stage for patients with a history of alcohol abuse. For patients without history of alcohol abuse, the correlation between disease stage, AST/ALT ratio, and platelet counts was r = 0.297, p < 0.00, and r = 0.560, p < 0.00, respectively. In these patients, AST/ALT ratio > or =1 in combination with a platelet count of <150,000/mm3 can identify patients with severe fibrosis or cirrhosis (stages 3 and 4) with a positive predictive value of 93.1%. Sensitivity, specificity, and negative predictive value were 41.2%, 99.1%, and 85.0%, respectively. In patients with ALT/AST ratio of <1 or platelet counts of >150,000/mm3, these laboratory parameters cannot predict liver fibrosis stage. CONCLUSION: AST/ALT ratio in combination with platelet counts may obviate a liver biopsy for fibrosis staging in some patients with chronic HCV infection.

Adult↗
PubMed2000

Towards single-particle spectroscopy of small metal clusters

We investigate the kinetic-energy spectra of electrons emitted from a metal cluster following laser excitation. This is done in the framework of a coupled ionic and electronic dynamics. Properly chosen laser parameters, leading to gentle excitations, yield kinetic-energy spectra which nicely resolve the multiphoton processes for each occupied state separately. This gives access to the single-particle energies in clusters, provided one works at sufficiently low temperatures and low electron flow.

Journal Article↗
PubMed2000

Plasma lipid and blood glucose levels in patients with destructive periodontal disease.

Hyperlipidaemia and hyperglycaemia are major risk factors for cardiovascular disease. In recent years, some evidence has been presented that periodontal disease is associated with an increased risk of cardiovascular disease. To further elucidate this association, we have studied standard blood chemistry variables known as risk markers for cardiovascular disease in periodontally diseased and healthy subjects. We have measured levels of plasma lipids and fasting blood glucose in 39 subjects with moderate periodontal disease (age 50-60 years) and compared the results with those obtained in 40 age- and sex-matched controls. Both groups were systemically healthy according to their medical history. Total cholesterol, low density lipoprotein cholesterol and triglycerides were significantly higher in periodontally diseased subjects by about 8% (p<0.03), 13% (p<0.003) and 39% (p<0.001), respectively, when compared to controls. Although subjects with diabetes were excluded from the study, we found significantly higher blood glucose levels in the patient than in the control group (85 +/- 25 versus 73 +/- 17 mg/dl; p<0.02). There was also a significantly higher frequency of pathological plasma lipid profiles in the patient than in the control group. The results indicate that hyperlipaemia and pre-diabetes may be associated with periodontal disease in systemically healthy subjects. These data do not allow us to decide, whether periodontal disease causes an increase in hyperlipaemia and in a prediabetic state or whether periodontal disease and cardiovascular disease share hyperlipidaemia and the prediabetic state as common risk factors.

Aged↗
PubMed2000

Docosahexaenoic acid transfer into human milk after dietary supplementation: a randomized clinical trial.

Docosahexaenoic acid (DHA) is important for infant development. The DHA transfer from maternal diet into human milk has not been investigated in detail. We studied the effects of DHA supplementation on the fatty acid composition of human milk and the secretion of dietary (13)C-labeled fatty acids, including DHA, into human milk. Ten lactating women were randomized to consume, from 4 to 6 weeks postpartum, an oil rich in DHA (DHASCO, 200 mg of DHA/day) (n = 5) or a placebo oil (n = 5). Dietary intakes were followed by 7-day protocols. On study day 14 a single dose of [U-(13)C]DHASCO was given orally, milk samples were collected over 48 h, and milk production was recorded. Milk fatty acid composition was determined by gas-liquid chromatography and isotopic enrichment was determined by gas chromatography- combustion-isotope ratio mass spectrometry (GC-C-IRMS). Milk DHA content did not differ between the supplemented and placebo group at study entry (0.29 vs. 0.28 wt%, median). After 2 weeks of supplementation the milk DHA content was almost 2-fold higher in the supplemented versus placebo group (0.37 vs. 0.21 wt%, P = 0.003). Cumulative recovery of [(13)C]palmitic, [(13)C]oleic, and [(13)C]docosahexaenoic acids in human milk at 48 h was similar between supplemented and placebo groups (palmitic acid 7.40 vs. 8. 14%, oleic acid 9.14 vs. 9.97%, and docosahexaenoic acid 9.09 vs. 8. 03% of dose, respectively). Notable lower recovery was observed for [(13)C]myristic acid in both the supplemented and placebo groups, 0. 62 versus 0.77% of dose. Dietary DHA supplementation increases the DHA content in human milk. DHA transfer from the diet into human milk is comparable to palmitic and oleic acid transfer.

Adult↗
PubMed1999

Oxidation of an oil rich in docosahexaenoic acid compared to linoleic acid in lactating women.

BACKGROUND: We studied the oxidation of an oil rich in docosahexaenoic acid (DHA; DHASCO((R))) in lactating mothers receiving a dietary DHA supplement or a placebo. The results were compared with the oxidation of linoleic acid. METHODS: Breast-feeding mothers received a dietary supplement (DHASCO; 200 mg DHA/day, n = 5) or a placebo (n = 5) for 14 days. Six weeks post partum all 10 mothers received a single dose of 2 mg/kg body weight uniformly (13)C-labeled DHASCO. In a previously reported study 6 mothers received 1 mg/kg body weight uniformly (13)C-labeled linoleic acid. Breath samples were collected over 48 h after tracer application. The total CO(2) production was measured by indirect calorimetry and the (13)C isotopic enrichment of labeled CO(2) by isotopic ratio mass spectrometry. RESULTS: The oxidation of (13)C-labeled DHASCO in the supplemented and placebo groups was similar. Maximal (13)C enrichment was reached earlier in the group receiving (13)C-DHASCO (median 1.0 vs. 3.0 h in the linoleic acid group). The cumulative (13)C recovery in breath was higher in the DHASCO versus the linoleic acid group until 10 h after tracer application and comparable thereafter. CONCLUSIONS: The difference in oxidation of DHASCO versus linoleic acid after tracer ingestion might be partly due to a faster absorption and oxidation of shorter chain saturated fatty acids contained in DHASCO. The cumulative oxidation of DHASCO and linoleic acid 24 and 48 h after tracer ingestion is similar.

Adult↗
PubMed1996

Chronic treatment with carbachol sensitizes the myocardium to cAMP-induced arrhythmia.

BACKGROUND: The present study investigated biochemical and functional consequences of chronic activation of the inhibitory Gi alpha-coupled adenylyl cyclase pathway in the heart. METHODS AND RESULTS: Rats (220 to 260 g) were treated with 4-day infusions of the M-cholinoceptor agonist carbachol (9.6 mg/kg per day) or vehicle. An additional group that received the beta-adrenoceptor agonist isoprenaline (2.4 mg/kg per day) served as control. The main finding was that chronic infusion of carbachol led to a marked increase in isoprenaline- or forskolin-induced arrhythmia in electrically driven papillary muscles (in vitro). Compared with control, the potency of isoprenaline and forskolin to induce arrhythmia in cardiac preparations from carbachol-treated rats was increased 36- and 2.2-fold and the efficacy was increased 7.3- and 2.3-fold, respectively. The potency of carbachol to antagonize the isoprenaline- and forskolin-induced arrhythmia was decreased 30-fold. These changes were accompanied by a decrease in left ventricular M-cholinoceptor density by 15% (P < .05) and a decrease in pertussis toxin-sensitive G proteins (Gi alpha) by 26% (P < .05) without a decrease in the corresponding mRNAs. beta-Adrenoceptor density and basal and stimulated adenylyl cyclase activity remained unchanged. In contrast, isoprenaline infusion induced a decrease in arrhythmogenic potency of forskolin (P = NS), which was accompanied by a decrease in beta-adrenoceptor density, an increase in Gi alpha protein and mRNA levels, and a decrease in basal and stimulated adenylyl cyclase activity. CONCLUSIONS: Chronic parasympathetic activation sensitizes the myocardium to cAMP-induced arrhythmia. These changes may be due to quantitative alterations in functional Gi alpha.

Adenylate Cyclase Toxin↗
PubMed1996

Growth inhibition in clonal subpopulations of a human epithelioid sarcoma cell line by retinoic acid and tumour necrosis factor alpha.

Epithelioid sarcoma is a highly malignant soft tissue tumour that is refractory to conventional chemotherapy and irradiation. Since permanent cell lines of this tumour are extremely rare, in vitro data on compounds with significant antiproliferative effects are still lacking. Therefore, we investigated the effects of retinoic acid (RA) and tumour necrosis factor alpha (TNF-alpha) on tumour cell proliferation of three different clonal subpopulations (GRU-1A, GRU-1B, GRU-1C) derived from the same human epithelioid sarcoma cell line, GRU-1. In GRU-1A both RA (P=0.01) and TNF-alpha (P=0.002) exhibited highly significant and dose-dependent growth inhibitory effects, which could further be increased by a combined application of both compounds (P<0.006). GRU-1B proved to be sensitive to RA (P=0.006), whereas no response to TNF-alpha was observed. GRU-1C was resistant to both RA and TNF-alpha. The antiproliferative effect of TNF-alpha was mediated by TNF receptor 1(TNF-R1) and correlated positively with both the number of TNF-R1 per cell and receptor affinity. No correlation was detected between RA-induced growth inhibition and the expression pattern of the RA receptors (RARs) RAR-alpha, RAR-beta, and RAR-gamma. Plating efficiency, however, could exclusively be reduced by RA in GRU-1B, the only cell line expressing RAR-alpha. Taken together, these data are the first showing significant antiproliferative effects in human epithelioid sarcoma by RA and TNF-alpha. Whereas the TNF-alpha response seems to depend on the expression of TNF-R1, no simple correlation could be found between RA sensitivity and the expression pattern of RARs.

Antineoplastic Agents↗
PubMed1994

Interclonal heterogeneity in a human epithelioid-sarcoma cell line (GRU-1).

Three clonal sub-populations, GRU-IA, GRU-IB, and GRU-IC, isolated from the human epithelioid sarcoma cell line GRU-I, were characterized morphologically, cytogenetically and with regard to proliferation kinetics. Immunocytochemically, major differences became evident in the expression of cytokeratin 18 and neurofilament proteins, which are indicative for epithelial and neural differentiation respectively. Vimentin, a mesenchymal differentiation marker, however, could be detected in all tumor cells of each sub-population. Laminin, a major compound of basement membranes, formed abundant intercellular network-like patterns in GRU-IB and GRU-IC, whereas GRU-IA was characterized by a diffuse intracellular reaction, suggesting a disorder in laminin secretion. Cytogenetically, all sub-populations proved to be DNA-aneuploid, the DNA index ranging from 1.4 to 1.5. Proliferation analysis revealed doubling times ranging from 13 (GRU-IC) to 19 hr (GRU-IA). These strictly defined clonal sub-populations provide a valuable tool for further investigations of the biological behavior of human epithelioid sarcoma with special regard to tumor heterogeneity.

Aneuploidy↗