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  • 1
    ISSN: 1432-0789
    Keywords: Key words Methane oxidation ; Land use ; Fertilization ; Pesticide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  In a first experiment, the effect of land use on the uptake rate of atmospheric CH4 was studied in laboratory incubations of intact soil cores. A soil under deciduous forest showed the highest CH4 oxidation. Its overall CH4 uptake during the measuring period (202 days) was 1.03 kg CH4 ha–1. Natural grassland showed the second highest CH4 oxidizing capacity (0.71 kg CH4 ha–1). The overall amount of CH4 uptake by fertilized pasture was 0.33 kg CH4 ha–1. CH4 oxidation in arable soils with different fertilizer treatments varied between 0.34 and 0.37 kg CH4 ha–1. Undisturbed soils had a higher CH4 uptake capacity than agricultural soils. The moisture content of the soil was found to be an important parameter explaining temporal variations of CH4 oxidation. Different methods of fertilization which had been commenced 10 years previously were not yet reflected in the total CH4 uptake rate of the arable soil. In a second experiment, a number of frequently used pesticides were screened for their possible effect on CH4 oxidation. In a sandy arable soil lenacil, mikado and oxadixyl caused significantly reduced CH4 oxidation compared to the control. Under the same conditions, but in a clayey arable soil, mikado, atrazine and dimethenamid caused a reduction of the CH4 uptake. In a landfill cover soil, with a 100-fold higher CH4 oxidation rate, no inhibition of CH4 oxidation was observed, not even when the application rate of pesticides was tenfold higher than usual.
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  • 2
    ISSN: 1433-0385
    Keywords: Key words: Malignant melanoma ; Lymph node metastases ; Lymph node dissection ; Prognosis. ; Schlüsselwörter: Malignes Melanom ; Lymphknotenmetastasierung ; Lymphknotendissektion ; Prognose.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Die Indikation zur elektiven Lymphknotendissektion, ihre evtl. zukünftige Bedeutung als Stagingmaßnahme vor adjuvanten Therapieverfahren, die Prognose der therapeutischen Dissektion sowie die Identifizierung des Pförtner-Lymphknotens und die daraus sich ergebenden therapeutischen Konsequenzen sind die wichtigsten Aspekte der Lymphknotendissektion beim malignen Melanom. Die Indikation zur elektiven Dissektion orientiert sich nicht nur an der pT-Kategorie, sondern auch an der Tumorlokalisation, dem Tumortyp und dem Geschlecht des Patienten. Ein allgemein akzeptierter Konsens zur Auswahl der in Frage kommenden Patienten besteht noch nicht. Da die ersten Studien mit Chemo-/Immuntherapie bei nodal positiven Patienten eine Prognoseverbesserung zeigen, muß zukünftig auch die Lymphknotendissektion als Stagingmaßnahme diskutiert werden. Neue Anregungen wurden in den letzten Jahren durch die Identifikation des Pförtner(„sentinel“)-Lymphknotens eingebracht. Diese Methodik bedarf noch der weiteren Evaluierung, dürfte aber zukünftig einen wesentlichen Einfluß auf die Indikation zur elektiven Lymphknotendissektion nehmen. Mit eingetretener Lymphknotenmetastasierung verschlechtert sich die Prognose des malignen Melanoms global um 20–50 %, abhängig vom Ausmaß der Metastasierung. Die Thematik wird anhand der eigenen Ergebnisse diskutiert.
    Notes: Summary. Elective lymph node dissection and its potential as a staging procedure, the prognosis of established lymph node metastases and the sentinel lymph node identification procedure are the most important aspects of lymph node dissection in malignant melanoma. It is widely accepted that subgroups of patients benefit from elective lymph node dissection. The question of which parameters identify the relevant patients properly is still under discussion. pT-categories are the most important prognostic factor; however, localisation and type of tumour and the sex of the patients are additional parameters influencing patient selection. Recently, the first studies have identified subgroups of nodal positive patients who would profit from adjuvant chemo-/immunotherapy. Therefore, lymph node dissection as a staging procedure has to be discussed in the future. Identification of the sentinel lymph node is receiving increasing attention because of its potential influence on the reassessment of elective lymph node dissection. However, this method needs further evaluation. If lymph node metastases have occurred, the prognosis of malignant melanoma decreases by 20 %–50 %, depending on the extent of metastasis in the individual case. The relevant topics and results are discussed on the basis of data of the Surgical Department of the University Hospital of Erlangen-Nuremberg.
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  • 3
    ISSN: 1433-0407
    Keywords: Schlüsselwörter ALS ; Neurogenetik ; Exzitatorische Aminosäuren ; Cu/Zn-SOD ; Key words Amyotrophic lateral sclerosis ; Neurogenetics ; Excitatory amino acids ; Cu/Zn SOD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary At presently, the etiology and pathogenesis of amyotrophic lateral sclerosis (ALS) are unknown. In recent years, the genetic background of hereditary motor neuron diseases has been partly defined. In particular, these advances represent an opportunity to improve our understanding of the pathogenesis of the familial and sporadic forms of ALS and thus provide a basis for rational therapeutic approaches. In this article, recent findings on the pathogenesis of the familial form of ALS and their implications for the sporadic form are discussed.
    Notes: Zusammenfassung Die Ätiologie und Pathogenese der amyotrophen Lateralsklerose (ALS) bleibt weitgehend ungeklärt. In den zurückliegenden Jahren sind bei den genetisch bedingten Varianten dieser Erkrankung wichtige Fortschritte bei der Identifizierung ihrer molekularbiologischen Grundlagen gemacht worden. Diese Fortschritte berechtigen zu der Hoffnung, daß es in Zukunft gelingt, die Pathogenese der familiären, aber auch der sporadischen Formen der Erkrankung zu erhellen und damit rationalen Therapieansätzen weiter den Weg zu bereiten. Im Rahmen dieser Übersichtsarbeit soll sowohl auf die vorliegenden Befunde bei der familiären Form der ALS (fALS) als auch auf die mögliche Bedeutung dieser Befunde für pathogenetische Vorstellungen bei der sporadischen Form der ALS (sALS) eingegangen werden.
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  • 4
    ISSN: 1432-0428
    Keywords: Key words Type II diabetes mellitus ; diabetic nephropathies ; epithelial cell ; glomerulus ; Indians ; North American.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. The predictive value of glomerular structure on progression of renal disease was examined in patients with Type II (non-insulin-dependent) diabetes and microalbuminuria (urinary albumin-to-creatinine ratio = 30–299 mg/g). Methods. Kidney biopsy specimens were obtained from 16 diabetic Pima Indians (6 men, 10 women). Progression of renal disease was assessed by measuring urinary albumin excretion 4 years after the biopsy (UAE4 years) and by computing the change in urinary albumin excretion during the study (Δ UAE). Results. At baseline, the duration of diabetes averaged 13.3 years (range = 4.0–23.8 years) and the mean glomerular filtration rate was 159 ml · min–1· 1.73m–2 (range = 98 – 239 ml · min–1· 1.73m–2). Median urinary albumin excretion was 67 mg/g (range = 25–136 mg/g) and it increased to 625 mg/g (range = 9–13471 mg/g) after 4 years; 10 subjects (63 %; 4 men, 6 women) developed macroalbuminuria (urinary albumin-to-creatinine ratio ≥ 300 mg/g). Neither mean arterial pressure nor HbA1 c changed substantially during follow-up. Among the glomerular morphologic characteristics, the number of visceral epithelial cells, or podocytes, per glomerulus was the strongest predictor of renal disease progression (UAE4 years, r = –0.49, p = 0.05; ΔUAE, r = –0.57, p = 0.02), with fewer cells predicting more rapid progression. Glomerular basement membrane thickness did not predict progression (UAE4 years, r = 0.11, p = 0.67; ΔUAE, r = 0.09, p = 0.73) and mesangial volume fraction had only a modest effect (UAE4 years, r = 0.42, p = 0.11; ΔUAE, r = 0.48, p = 0.06). Conclusion/interpretation. Whether lower epithelial cell number per glomerulus among those that progressed was due to cellular destruction, a reduced complement of epithelial cells, or both is uncertain. Nevertheless, these findings suggest that podocytes play an important part in the development and progression of diabetic renal disease. [Diabetologia (1999) 42: 1341–1344]
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  • 5
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: During development motoneurons depend on target contact for their survival. Following injury to the sciatic nerve in neonatal rats, a large proportion of motoneurons die. However, the same injury inflicted at 5 days of age results in no loss of motoneurons. This critical period of postnatal development coincides with the time during which there is a significant increase in the release of transmitter from the nerve terminals at the neuromuscular junction. We have proposed that the role of the target muscle cell during this period is to induce this up-regulation of transmitter release from motor nerve terminals. It has been shown that stretch-induced increase in transmitter release from frog motor nerve terminals is accomplished via an integrin-dependent mechanism. In this study we examined the role of integrins at the rat neuromuscular junction in motoneuron survival. We found that blocking integrin binding at the developing neuromuscular junction delayed the increase in choline acetyltransferase activity that normally takes place during the early postnatal period, and resulted in motoneuron death. Furthermore, the maturation of those motoneurons that survived was delayed so they remained susceptible to subsequent nerve injury. These results support the possibility that integrins, by their involvement in modulating transmitter release, can influence motoneuron survival.
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  • 6
    ISSN: 1435-1285
    Keywords: Key words Coronary heart disease – dynamic stress echocardiography – normative values – heart rate – lactate ; Schlüsselwörter Koronare Herzerkrankung – dynamische Streßechokardiographie – Normwerte – Herzfrequenz – Laktat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 25 Patienten mit koronarer Herzerkrankung (KHK, 62 ± 9 Jahre) und 18 Herzgesunde (28 ± 6 Jahre) absolvierten je eine stufenförmige fahrradergometrische Belastung in sitzender Position und eine Streßechokardiographie in halbliegender Linksseitenlage. Während sich bei den Gesunden für die Herzfrequenz, den Blutdruck und das Druck-Frequenz-Produkt keine wesentlichen Unterschiede zwischen den beiden Belastungsformen nachweisen ließen (2 × 3 ANOVA, t-Tests mit α-Adjustierung), zeigten die KHK-Patienten auf gleichen Belastungsstufen signifikant höhere Herzfrequenzen und ein signifikant höheres Druck-Frequenz-Produkt (bei 50 W: 15 300 ± 2793 mmHg/min vs. 13 822 ± 3042 mmHg/min; bei 75 W. 18 028 ± 3479 mmHg/min vs. 16 337 ± 2619 mmHg/min) bei der Streßechokardiographie im Vergleich zur Fahrradergometrie in sitzender Position. Keine Unterschiede fanden sich in dieser Gruppe für den systolischen Blutdruck; der diastolische Blutdruck war lediglich in Ruhe und bei der Eingangsstufe von 50 W im Sitzen höher. Die Laktatkonzentrationen (nur bei den Gesunden gemessen) lagen auf allen Belastungsstufen der Streßechokardiographie signifikant höher, die Leistung an der individuellen anaeroben Schwelle (IAS) war signifikant niedriger. Schlußfolgernd besteht für Gesunde bei der Streßechokardiographie im Vergleich zur herkömmlichen Fahrradergometrie auf gleichen Belastungsstufen eine höhere metabolische bei vergleichbarer kardiozirkulatorischer Beanspruchung. KHK-Patienten hingegen erfahren in der halbliegenden Linksseitenlage eine höhere Belastung für das Herz-Kreislauf-System gegenüber der sitzenden Körperposition. Es ist bei Untersuchungen dieser Patienten mit um etwa 8 Schläge/min höheren Herzfrequenzen auf den einzelnen Stufen zu rechnen.
    Notes: Summary 25 patients with coronary heart disease (CHD, 62 ± 9 years) and 18 subjects free from cardiovascular disease (28 ± 9 years) were tested on a cycle ergometer using a graded incremental test protocol: a) in the common upright position, b) as dynamic stress echocardiography in a semi-supine position. Whereas no relevant differences could be detected between the two conditions for the healthy subjects concerning heart rate, blood pressure, and rate-pressure product (2 × 3 ANOVA, t-test with α-adjustment), the CHD patients showed both significantly higher heart rates as well as a significantly higher rate-pressure product (50 W: 15 300 ± 2973 mmHg/min vs. 13 822 ± 3042 mmHg/min; 75 W: 18 028 ± 3479 mmHg/min vs 16 337 ± 2619 mmHg/min) on equivalent stages during stress echocardiography if compared to the sitting position. There were no differences for systolic blood pressure in this group; the diastolic values were higher in the sitting position at rest and during 50 W. Lactate concentrations (determined only in the healthy subjects) were significantly higher on all stages during dynamic stress echocardiography. The workload at the individual anaerobic threshold (IAT) was significantly lower. In conclusion, we found a higher metabolic along with a similar cardiovascular strain at equivalent workloads in stress echocardiography compared to upright bicycle ergometry for healthy subjects. However, CHD patients have a higher cardiocirculatory load in the semi-supine position. When investigating these patients with stress echocardiography, higher heart rates of about 8 beats/min have to be expected for equivalent workloads if compared to the upright position.
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  • 7
    ISSN: 1617-4623
    Keywords: Key words 3-Dehydroquinate synthetase ; Aromatic amino acid synthesis ; aroK ; yafJ ; Cell invasion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The gene coding for the 3-dehydroquinate synthetase (aroB) of Neisseria gonorrhoeae has been cloned by functional complementation of an Escherichia coli aroB mutant. The aroB gene isolated from a gonococcal plasmid library encodes a 359 amino acid protein with a molecular mass of 38.6 kDa. Alignment of different prokaryotic and eukaryotic aroB gene products reveals an overall identity ranging from 33 to 55%. An open reading frame coding for an aroK homologue is located immediately upstream of aroB. Downstream of aroB a region of inverted repeats and a gene showing high homology to yafJ of E. coli has been identified. Disruption of aroB generates a gonococcal mutant that is unable to grow in the absence of aromatic compounds. Complementation of the mutant with the intact aroB gene intrans indicates that the gene is responsible for the auxotrophic phenotype. In infection assays with AroB-deficient gonococcal strains, binding, entry and short-term survival in epithelial cells is not affected. The aroB gene might be useful as a selectable marker and target for attenuation of a gonococcal live vaccine strain or as a biosafe laboratory strain.
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  • 8
    ISSN: 1617-4623
    Keywords: Gonococcus ; Folic acid ; Dihydrofolate synthetase ; Folylpolyglutamate synthetase ; One-carbon metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The gene coding for folylpoly-(γ)-glutamate synthetase (FPGS)-dihydrofolate synthetase (DHFS) ofNeisseria gonorrhoeae (Ngo) has been cloned by functional complementation of anEscherichia coli folC mutant (SF4). The sequence encodes a 224-residue protein of 46.4 kDa. It shows 46% identity to theE. coli FPGS-DHFS and 29% identity to the PFGS ofLactobacillus casei. Sequence comparisons between the three genes reveal regions of high homology, including ATP binding sites required for bifunctionality, all of which may be important for FPGS activity. In contrast toL. casei FPGS, theE. coli andNgo enzymes share some additional regions which may be essential for DHFS activity. The products ofNgo folC and flanking genes were monitored by T7 promoter expression. Interestingly, deletion of the upstreamfolI gene, which encodes a 16.5 kDa protein, abolishes the capacity offolC to complementE. coli SF4 to the wild-type phenotype. The ability to complement can be restored byfolI providedin trans. UnlikefolC mutants, gonococcalfolI mutants are viable and display no apparent phenotype. Thus, in contrast toE. coli, Ngo folC is expressed at a sufficiently high level from its own promoter, in the absence of FolI. This study provides the first insights into the genetic complexity of one-carbon metabolism inNgo.
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  • 9
    ISSN: 1617-4623
    Keywords: Key words Gonococci ; aniA ; Pan1 ; Nitrite reductase ; Anaerobiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The aniA gene of Neisseria gonorrhoeae encodes an outer membrane lipoprotein which is strongly induced when gonococci are grown anaerobically in vitro in the presence of nitrite. Database searches with the amino acid sequence derived from the aniA structural gene revealed significant homologies to copper-containing nitrite reductases from several denitrifying bacteria. We constructed an insertional mutation in the aniA locus of strain MS11 by allelic replacement, to determine whether this locus was necessary for growth in oxygen-depleted environments, and to demonstrate that AniA was indeed a nitrite reductase. The mutant was severely impaired in its ability to grow microaerophilically in the presence of nitrite, and we observed a loss in viability over several hours of incubation. No measurable nitrite reductase activity was detected in the aniA mutant strain, and activity in the strain with a wild-type locus was inducible. Finally, we report investigations to determine whether AniA protein is involved in gonococcal pathogenesis.
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  • 10
    ISSN: 1617-4623
    Keywords: Key wordsManduca sexta ; Southern hybridization ; Cry1Ab ; Bacillus thuringiensis ; BT-R1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Various subspecies of the gram-positive bacterium Bacillus thuringiensis are known to produce a wide array of insecticidal crystal proteins (ICPs) upon sporulation. These ICPs act primarily on the brush border of midgut epithelial cells of susceptible larvae. Recently, a protein of 210 kDa, isolated from the midgut of Manduca sexta, has been demonstrated to bind the Cry1Ab toxin produced by B. thuringiensis subsp. berliner and is therefore postulated to be involved in mediating the toxicity of Cry1Ab. The cDNA encoding the 210 kDa protein, termed BT-R1 (Bacillus thuringiensis receptor-1), was recently cloned, and shows limited homology to the cadherin superfamily of proteins. Quite naturally, there is a great deal of interest in the characterization of BT-R 1 , the gene encoding the 210 kDa Cry1Ab binding protein. The studies presented here involve the use of various restriction fragments prepared from the cDNA encoding BT-R1 as probes of Southern blots bearing M. sexta genomic DNA cleaved with a variety of restriction endonucleases. These Southern blot data reveal that there are two discrete regions within the M. sexta genome which encode sequences homologous to BT-R1. On the basis of the signal intensities seen on Southern blots, it appears that only one of these genes encodes BT-R1, whereas the other is a closely related homologue.
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