9 research outputs found
Role of exposure period in applying gaseous mutagens to Drosophila, as exemplified by 1,2-dichloroethane and methylbromide
Investigations on the mutagenicity of NO2 gas in Drosophila melanogaster
Het vermogen van NO2 gas om bij de bananevlieg (Drosoph. melanogaster) mutaties te induceren werd onderzocht d.m.v. de geslachtsgekoppelde recessief-letaal test. Tevens werden effecten van NO2 op overleving en fertiliteit nagegaan. Vliegen werden blootgesteld gedurende perioden van 1 tot 3 weken, aan NO2 concentraties van 5, 15 of 50 mg/m3 (6 uur per dag, 5 dagen per week) of 20 mg/m3 (continu). Er is mogelijk sprake van een verhoogde sterfte a.g.v. blootstelling aan NO2. Een geringe vermindering van de fertitliteit bij de mannetjes werd in 3 van de 4 experimenten waargenomen en was in een geval significant. In twee mutageniteitsexperimenten werd geen verhoogde mutatie- frequentie gevonden in de met NO2 behandelde groep. Dit resultaat is niet onverwacht gezien de in twee Japanse publikaties gerapporteerde negatieve of marginale effecten bij aanzienlijk hogere blootstellingsniveaus. Uit in de literatuur vermeld mutageniteitsonderzoek met andere testsystemen blijkt vooral het vermogen van NO2 om chromosoomafwijkingen te veroorzaken.DGMH/
Epistemologia dell\u2019insegnante di matematica sulla sua conoscenza professionale. (Parte III: Metodologia e risposte alle domande di ricerca D1-D4).
Le prime due parti di questo lavoro si trovano nei precedenti due numeri della rivista. Nella prima parte \ue8 stato descritto il quadro teorico ed \ue8 stata fatta una rassegna di alcuni risultati di ricerca. Nella seconda parte \ue8 stata completata la rassegna dei principali risultati di ricerca sul tema in esame e sono stati introdotti i problemi sui quali si \ue8 focalizzata questa ricerca.
In questa terza parte si descrive la metodologia utilizzata per indagare l\u2019epistemologia dell\u2019insegnante di matematica sulla sua conoscenza professionale e si riportano e discutono alcuni risultati ottenuti
Evaluation of diphtheria convalescent patients to serve as donors for the production of anti-diphtheria immunoglobulin preparations
Aims: The study was conducted to evaluate the possibility of selecting convalescent diphtheria patients to serve in emergency situations as donors for the production of anti-diphtheria immunoglobulin. To select suitable donors, the criterion of an antitoxin titer ≥3.0 IU/ml was used. In addition, the effects of treatment and the effect of immunization with diphtheria toxoid on the level of anti-diphtheria toxin antibodies were evaluated. Scope: Three groups of diphtheria patients were included in the study. The first group (n=23) consisted of patients who had a basic antibiotic treatment, with or without serotherapy using horse antitoxin and/or human immunoglobulin. The second group (n=12) comprised patients examined immediately after the onset of disease. The immunological history of this group was not known. The third group (n=20) included patients with a known immunization history, treated only with antibiotics but having received a booster immunization with diphtheria toxoid. Antitoxin titers were measured using the toxin binding inhibition (ToBI) assay. Conclusions: In the first group, 47.8% (11/23) of the patients had a diphtheria antibody titer ≥3.0 IU/ml. For most of them, however, the antibody titers could have resulted from treatment with exogenous antibodies from horse antitoxin or human immunoglobulin (18/23). Only two of the 11 high-titer subjects had received antibiotics only. Among the second group, only two (16.76%) of the patients had an antibody titer of ≥3.0 IU/ml. In the third group 50% (10/20) of the patients showed an antibody titer of ≥3.0 IU/ml prior to vaccination, and therefore could be directly considered as donors. Three weeks after booster vaccination, 70% (14/20) had an antibody titer of ≥3.0 IU/ml and 1 year after booster vaccination, 28.6% (2/7) of the subjects still had titers of ≥3.0 IU/ml. In 40% of these patients, a decrease was observed 3-4 weeks after the booster dose. It was concluded that convalescent diphtheria patients could be considered as donors in an emergency situation, since approximately half of them showed antitoxin titers of ≥3.0 IU/ml. © 2003 Elsevier Ltd. All rights reserved
Polimorphism of bovine MHC class II genes
Polymorphism of the bovine DRB, DQA, DQB, DYA, DOB and DIB genes was investigated using restriction fragment length polymorphism (RFLP) analysis, isoelectric focusing (IEF), class II serology and polymerase chain reaction (PCR) based typing techniques. The simultaneous application of multiple typing techniques and the characterization of multiple genes resulted in a greatly enhanced picture of the bovine class II regions. Thirty-eight class IIa (DR-DQ) and 5 class lib (DYA-DOB-DIB) haplotypes were defined. It was found that IEF types were associated with DRB3 polymorphism defined by DRB3 PCR-RFLP and DRB3 microsatellite PCR. Serologically defined polymorphism was associated with distinct molecular/IEF motifs and, therefore, DR and DQ specificities could be tentatively distinguished. Although the DR and DQ genes are tightly linked, neither DR nor DQ typing defined all of the class IIa region polymorphism. Furthermore, even the most powerful DRB3 typing technique, DRB3 PCR-RFLP, failed to detect all expressed DRB3 polymorphism. All detected DRB3 polymorphism could, however, be distinguished with a combination of two molecular techniques: DRB3 PCR-RFLP and DRB3 microsatellite PCR. RFLP typing with transmembrane probes detected significantly less polymorphism than typing with cDNA or exon probes. However, the transmembrane probes were useful because they were locus specific. The presence of only 5 of 12 possible class lib haplotypes was unexpected and indicates that the DYA, DOB and DIB genes are tightly linked