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  • 1
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Ergebnisse aus einer Feldstudie zur Ökologie eines Wirt-Parasit Systems, bestehend aus mehreren Arten von parasitoiden Fliegen (Conopidae, Diptera) und ihren Hummel-Wirten (Bombini, Apoidea, Hymenoptera), werden dargestellt. Wirtstiere wurden systematisch in verschiedenen Untersuchungsgebieten über eine ganze Saison gesammelt und auf erfolgreiche Parasitierung, erkennbar am Puparium der endoparasitischen Fliege, geprüft. Parasitierung erfolgt vor allem in den Sommermonaten (Juli–September), wobei die beobachtete maximale Häufigkeit des Befalls 46.7% (für Arbeiterinnen) betrug. Durchschnittlich sind 13.2% aller Arbeiterinnen (Spannweite: 0–46,7%) und 7.1% aller Männchen (0–28.6%) befallen, d.h. enthielten ein Puparium wenn die Tiere nach ihrem Tod im Labor eröffnet wurden. Zwei Conopiden-Gattungen,Sicus (64% der Beobachtungen) undPhysocephala (36%) waren zu finden, wobei die letztere später im Jahr häufiger wird. Eine multivariate Analyse zeigte, dass Wirtsart, Geschlecht (Arbeiterin, Männchen) und Undersuchungsgebiet die wichtigsten Faktoren sind, welche die Wahrscheinlichkeit der Parasitierung beeinflussen. Im Durchschnitt waren Männchen weniger befallen als Arbeiterinnen. Das ausgeprägte saisonale Auftreten der Conopiden scheint in erster Linie für die Unterschiede im Befall zwischen Wirtsarten verantwortlich zu sein. So sind frühe Arten (z.B.B. pratorum) und früh fliegende Königinnen vonBombus undPsithyrus im Frühjahr kaum befallen. Die Ergebnisse werden im Zusammenhang mit dem möglichen Einfluss der Conopiden auf die Ökologie und Evolution des Wirts diskutiert. Zusätzliche Beobachtungen über das Vorkommen weiterer wichtiger Endoparasiten (Sphaerularia bombi undSyntretus sp.) werden berichtet.
    Notes: Summary We present field data on the ecology of a host-parasite system, consisting of several species of parasitoid flies (Conopidae, Diptera) and their bumblebee hosts (Bombini, Apoidea, Hymenoptera). Host animals were systematically sampled from different study sites throughout a season and checked for successful infestation in the form of puparia of these endoparasitic flies. Such dissection of the bees revealed that infestation occurs primarily during the summer months (June to September), with an observed maximum frequency of parasitization of 46.7% in workers in one of our study sites. On average, 13.2% of all workers (range 0–46.7%) and 7.1% of all males (range 0–28.6%) contained the puparium of a conopid. Two conopid generaSicus (64% of cases) andPhysocephala (36%) accounted for the infestation, with the latter being more abundant later in the year. A multivariate analysis identified host species, sex (male or worker), and study area as the most important factors accounting for the observed variance in the probability of being parasitized during the summer months. On average, males were less affected than workers. The marked seasonal appearance of conopids seems to account for differences among species, in particular for low levels of infestation among species completing their life cycles early (e.g.B. pratorum) and among the early flying, hibernated quens ofBombus andPsithyrus species. The results are discussd with respect to the impact of conopids on host ecology and evolution. Additional observations on the occurrence of further endoparasites (Sphaerularia bombi andSyntretus sp.) are reported.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 48 (1992), S. 911-920 
    ISSN: 1420-9071
    Keywords: Cytotoxic T lymphocytes ; granules ; perforin ; gene targetting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The killing mediated by cytotoxic T lymphocytes (CTL) represents an important mechanism in the immune defence against tumors and virus infections. The lytic mechanism has been proposed to consist of a polarized secretion of granule-stored molecules, occurring on effector-target cell contact. By electron microscopy, membrane deposited, pore-like lesions are detected on the target cell membrane during cytolysis by CTL. These structures resembled strikingly pores formed during complement attack. Granules of CTL isolated by nitrogen cavitation and Percoll gradient centrifugation were shown to retain cytotoxic activity. Further purification of proteins stored in these granules led to the discovery of a membranolytic protein named perforin which was capable of polymerizing into pore-like structures. In addition to this cytolytic protein, a set of serine esterases was found as well as lysosomal enzymes and proteoglycans, whose function are not yet clearly defined. The role of perforin in the cytotoxic process is currently being explored by ablating the active gene in mice.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-055X
    Keywords: Schlüsselwörter: Alkoholismus – Alkoholentzugssyndrom – Kohlenhydrat-defizientes Transferrin (CDT) – Karzinompatienten ; Key words: Alcoholism – Alcohol withdrawal syndrome (AWS) – Carbohydrate Deficient Transferrin (CDT) – Cancer patients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract. The increase of alcoholism-related problems is associated with vital postoperative clinical complications in chronic alcohol abusers. In particular, the alcohol withdrawal syndrome (AWS) may provoke potentially life-threatening complications in alcohol-dependent patients. Hence, a precise diagnosis of alcohol dependence is mandatory preoperatively, requiring an extensive case history using alcoholism-associated questionnaires. Additional new biological markers for detecting alcoholism could improve the accuracy of preoperative diagnosis. Carbohydrate-deficient transferrin (CDT) reflects increased alcohol consumption. The aim of our interdisciplinary study was to investigate whether the validity of the preoperative diagnosis of chronic alcohol abuse might be improved by measuring CDT. Methods. A total of 45 patients from the departments of Otorhinolaryngology, Maxillofacial Surgery, and Abdominal and Thoracic Surgery were included in our prospective clinical study. Patients underwent resection of malignant oral, pharyngeal, laryngeal, or oesophageal tumours and were transferred to the intensive care unit for postoperative management. Routine preoperative history, examinations, and laboratory tests including GGT, MCV, ASAT, and ALAT, were supplemented by a specific alcohol-related questionnaire and CDT measurement. The patients were categorised in four groups based on history and the questionnaire: continuously abstinent subjects; sober subjects for at least 7 days; chronic abusers; and dependent subjects. CDT was separated by isocratic anion exchange chromatography and quantified by turbidimetric determination. Statistical analysis was performed by the Kruskal-Wallis test. Results. Preoperatively, 21 patients were at major risk for alcoholism-related complications: 12 were chronic abusers and 9 were diagnosed as dependent. CDT was significantly increased in both groups, and was pathologically elevated in 16 of the 21 patients. Sampling occurred significantly long after the last alcohol intake in the 5 patients with normal CDT values (median: 6.0 days; range: 2 – 12 days) compared with the 16 with pathologically elevated CDT levels (median: 1.0 day; range: 0 – 4 days; P=0.002). The sensitivity of CDT elevation was 16 out of 24 (76%), the specifity 16 out of 16 (100%). Sixteen patients had no previous history of alcohol consumption (sober for at least 7 days) and 8 were definitely abstinent. Both of these groups had normal CDT values. Conclusions. CDT was a sensitive and specific marker for chronic alcohol consumption in our patient population. Since CDT is a state marker, repeated determinations might be useful to estimate a patient's drinking habits. The combination of CDT and an alcohol-related questionnaire was reliable for detecting alcohol-dependent patients preoperatively.
    Notes: Zusammenfassung. Alkoholkranke Patienten sind in der postoperativen Phase auf der Intensivstation durch die Dekompensation alkoholismusinduzierter Folgeerkrankungen vital bedroht. Vor allem das Alkoholentzugssyndrom (AES) provoziert interkurrente Komplikationen und prolongiert die intensivmedizinische Behandlungsphase. Zur präoperativen Evaluierung der Alkoholabhängigkeit stehen standardisierte, alkoholismusrelevante Anamneseverfahren und konventionelle klinisch-chemische Laborparameter, wobei diese häufig keine ausreichende Sensitivität und Spezifität besitzen. Unter den biologischen "State-Markern" zur Detektion des chronischen Abusus wird dem Kohlenhydrat-defizienten Transferrin (CDT) hohe Sensitivität und Spezifität zugeschrieben. Wir prüften bei 45 Patienten, die sich der Resektion maligner Tumoren des Oropharynx, Larynx oder Ösophagus unterzogen und anschließend auf der operativen Intensivstation weiterbehandelt wurden, ob CDT in der präoperativen Diagnostik chronischen Alkoholabusus detektieren kann. 21 Patienten wurden als Gruppe mit hohem Risiko für postoperative Alkoholismus-assoziierte Komplikationen identifiziert. Davon wurden 12 Patienten als chronische Abuser und 9 Patienten als abhängig eingestuft. CDT war bei den alkoholkranken Patienten in 16 von 21 Fällen pathologisch erhöht. Im Gegensatz dazu hatten alle Patienten, die dauerhaft abstinent (8 Patienten) oder länger als 7 Tage nüchtern waren (16 Patienten), normale CDT-Werte. CDT war bei unseren Patienten ein spezifischer und sensitiver Marker zur Detektion des chronischen Alkoholabusus.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Low dispersal and sexual selection are characteristic of the coastal polychaeteNereis acuminata Ehlers 1868 [also known asNereis arenaceodentata Moore 1903 andNereis (Neanthes) caudata Delle Chiaje 1841]. We assessed levels of premating isolation between populations of this polychaete. Four North American populations were used, two from the Atlantic and two from the Pacific. Worms from all sites (1) were collected in 1987 and 1988 from the same habitat type, (2) were morphologically similar and keyed out asN. acuminata, and (3) reproduced monogamously and exhibited male parental care, an extremely rare reproductive mode in marine invertebrates. There was no evidence from 10-min or 36-h trials of premating isolation between the two Pacific populations. Incomplete premating isolation was found between the two Atlantic populations. High aggression and non-pairing occurred in some 10-min trials between males and females. However, in 36-h trials males and females from the two Atlantic populations always paired to mate. Complete premating isolation was found between Atlantic and Pacific populations. During 10-min trials, males and females from different oceans often attacked and then avoided each other, and they never paired to mate. Nor did they pair to mate in longer, 36-h trials. One Pacific and one Atlantic population were compared for tolerance to cold temperature. Pacific individuals were less able to tolerate cold water than Atlantic individuals. Two Atlantic populations studied had karyotypes with 11 pairs of small acrocentric chromosomes (2n=22), while the two Pacific populations had nine pairs of large metacentric or submetacentric chromosomes (2n=18). Such extreme dissimilarity in karyotype was not expected considering the similarity in morphology, habitat, and reproductive mode. Results suggest strongly that the Atlantic and Pacific populations have been allopatric for a long time, and are different species.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 71 (1993), S. 822-824 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We present the results of an international collaborative study aimed at estimating the ratio of male to female mutation rates in Duchenne muscular dystrophy based on the method of C. Müller and T. Grimm. With a sample size of 295, this ratio is found to be very close to 1, thus giving evidence for equal mutation rates in males and females in Duchenne muscular dystrophy.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Allele-specific differences in the regulation of HLA class I genes by type I interferon (IFN) were observed after transfection of eight HLA-B,-A, or-C genes into mouse L cells. HLA-B7 and -Bw64 gene expression was significantly more inductible by type I IFN than the genes coding for HLA-B27, HLA-B51, HLA-B38, HLA-B39, HLA-Cw3, and HLA-A2 antigens. Modification of the 5′ end of HLA-B7 and HLA-B27 genes revealed the presence of enhancer sequences responding to IFN treatment in the 5′ untranslated region of HLA-B7, but not of HLA-B27 and suggested further, independently acting enhancer elements downstream of the transciption initiation site. Comparison of 5′ enhancer region sequences in correlation with type I IFN inducibility of the different HLA class I alleles indicated that the exchange of only two nucleotides in the interferon response sequence (IRS) or enhancer A region of HLA-B7 or -Bw64 could account for nonregulated promoters in all other HLA-A,-B or -C alleles analyzed. Thus, type I IFN stimulation of HLA class I genes in mouse L cells appears to predominantly operate in most alleles by a mechanism targeted to enhancer sequences downstream of the gene's transcription initiation site.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 681 (1993), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Contact dermatitis 31 (1994), S. 0 
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 98 (1994), S. 11119-11125 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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