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The degradation of benzylpenicillin in aqueous solutionLipczynski, Andrew Martin January 1988 (has links)
No description available.
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Identification et caractérisation des peptides hapténisés avec la benzylpénicilline responsables de l’activation des cellules T naïves et de l’immunisation des patients allergiques à la pénicilline / Identification and characterization of benzylpenicillin-hapten peptides responsible for naïve T-cell activation and immunization of allergic patients to penicillinAzoury, Marie Eliane 23 March 2016 (has links)
Les pénicillines font partie des molécules chimiques les plus fréquemment impliquées dans l’allergie médicamenteuse. Selon l’hypothèse de l’haptène, les molécules chimiques de petite taille doivent se lier aux protéines pour êtres immunogènes. Cependant, très peu est connu sur le processus d’immunisation des patients aux bioconjugués pénicilline-protéine. Notre groupe a récemment synthétisé des bioconjugués albumine sérique humaine-benzylpénicilline (HSA-BP) et a démontré l'existence de lymphocytes T CD4+ naïfs spécifiques du bioconjugué HSA-BP chez des donneurs sains. L'objectif de ce travail de thèse est d'identifier des séquences peptidiques issus de la HSA hapténisées avec la BP, impliquées dans l’activation des cellules T naïves ainsi que l’immunisation des patients allergiques et par conséquent les manifestations cliniques. Notre stratégie combine la spectrométrie de masse, la modélisation moléculaire et le criblage virtuel, la synthèse chimique orientée et la validation biologique sur des lignées de cellules T de longues durées chez les donneurs sains, et à l’aide du test de transformation lymphocytaire ainsi que les lignées de cellules T de courte durée chez les patients allergiques. Cette étude a permis: (1) l’identification des résidus lysine présents sur la HSA hapténisés par la BP par spectrométrie de masse, (2) la sélection par une approche in silico des peptides de 15-mer potentiellement immunogènes, (3) la synthèse orientée de ces peptides-BP à l’aide d’un monomère lysine-BP, (4) l’identification des épitopes reconnus par les cellules T naïves de donneurs sains, (5) la validation de deux épitopes situés sur les lysines 159 et 525 chez les patients allergiques aux pénicillines et (6) confirmation de la HSA comme un bon modèle pour l’hapténisation de la BP. / Penicillins are among the most prevalent drug-inducing allergy. According to the hapten hypothesis small chemical molecules needs to bind to proteins to be immunogenic. However, little is known on the process of patients immunization to penicillin-protein conjugates. Our group has recently synthesized benzylpenicillin-human serum albumin (BP-HSA) bioconjugate and demonstrated the existence of naïve CD4+ T lymphocytes specific to BP-HSA in healthy donors. The objective of this work was to identify peptides sequences from HSA haptenized with BP involved in naïve T-cells activation, immunization of patients and consequently the clinical manifestations. Our strategy combines mass spectrometry, molecular modeling and virtual screening, chemical oriented synthesis and biological validation using long-term T-cell lines in healthy donors and the lymphocyte transformation test as well as short-term T-cell lines in allergic patients. This study allowed: (1) the identification of lysine residues involved in the BP binding to HSA using mass spectrometry, (2) the selection of BP-peptides containing the lysine residues likely to induce immune response using an in silico approach, (3) the synthesis of the selected BP-15 mer peptide bioconjugates using a lysine-BP monomer, (4) the identification of epitopes recognized by naïve T cells from healthy donors, (5) the validation of two epitopes located on lysines 159 and 525 in allergic patients to penicillins and (6) the confirmation of HSA as a good model for BP haptenation.
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Resistensbestämning med benzylpenicillin för Staphylococcus aureus vid diskdiffusion enligt EUCAST / Resistance testing of benzylpenicillin for Staphylococcus aureus by disc-diffusion according to EUCASTKlingén, Jenny, Twedmark, Amanda January 2024 (has links)
Efter upptäckten av penicillinet observerades en ökad resistens hos S. aureus vilket ledde till att alla stammar ansågs vara resistenta. Dock har många stammar enligt senare studier visat sig vara känsliga vilket har öppnat upp möjlighet att åter använda benzylpenicillin som ett behandlingsalternativ eftersom det kan ges i lägre koncentration jämfört med andra alternativ. Metoden för att upptäcka penicillinresistens hos S. aureus enligt EUCAST har bedömts svår att tillämpa på grund av subjektivitet vid bedömning av zonkanten. Studiens syfte var att utvärdera metoden för senare implementering på Klinisk Mikrobiologi Unilabs i Skövde. Metodens användbarhet utvärderades genom resistensbestämning av en referensstam samt tio stammar från ett referenslaboratorium för EUCAST. Bedömningen av de tio stammarna från referenslaboratoriet stämde vid jämförelse överens med deras resultat förutom för en stam som bedömdes som resistent i stället för känslig. Repeterbarheten var hög då ingen skillnad (p=0,156) uppvisades för referensstammen. Resultatet tyder på att det kan vara svårt att göra en korrekt tolkning av zonkantens utseende då det är en subjektiv bedömning. För att uppnå en högre säkerhet kan det vara fördelaktigt att mer än en person gör en bedömning. Slutsatsen var att metoden kan implementeras på laboratoriet. / Following the discovery of penicillin, resistance rates increased until all strains of S. aureus were considered resistant. Recent studies have shown that many strains are susceptible, making it possible to again use penicillin as an alternative for treatment since it can be used in lower concentrations compared to alternatives. The EUCAST method for discovering penicillin resistance in S. aureus has been judged difficult due to the subjectiveness of assessing the zone edge. The aim of this study was to evaluate the method to implement it in the Section for Clinical Microbiology Unilabs Skövde. The useability of the method was evaluated by resistance testing of a reference strain and ten strains from a EUCAST reference laboratory. The assessment of the strains from the reference laboratory equaled their results except for one strain that was assessed resistant rather than sensitive. The repeatability was high since no difference (p=0,156) was found for the reference strain. The results show how difficult it is to correctly assess the zone edge due to its subjectiveness. It could be beneficial with more than one person assessing the zone edge to achieve a higher security. In conclusion the method is possible to implement in the laboratory.
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Improving Antibiotic Availability by Restructuring the Supply Chain : A Case Study Within SwedenGarlapati, Shailesh, Sewoyo, Vinana January 2019 (has links)
Rising Antimicrobial Resistance is a threat faced all over the world. Bacterial infections that were treatable with antibiotics only a few years ago can now lead to life-threatening conditions. This thesis is part of the work of a large platform, PLATINEA, trying to reduce the rate of new resistances occurring in Sweden by preventing non optimal treatment. Due to shortages of the right antibiotics, suboptimal antibiotics are prescribed, which has shown to be accelerating the resistances among the bacterial populations. This study proposes an information exchange database and a central storage model for critical antibiotics to circumvent stock outs and inconveniences resulting from shortages of medically valuable antibiotics. Through interviewing prominent actors in the Swedish pharmaceutical supply chain an inside into the procurement of antibiotic in Sweden and what concerns are faced by the organs involved was created. Literature studies on occurred shortages of antibiotics in Sweden and the world were examined and possible reasons for these were identified. Examination of governmental efforts and assignments created the context in which gaps were identified that this thesis work could fill. A focus on Benzylpenicillin and Rifampicin were kept throughout the study. The collected data led to the implementation recommendation of two models by this study. An information platform suggested to allow better, faster and more accurate information exchange between all involved actors of the supply chain as well as a centralized storage model for the storage of antibiotics with medically high value in Sweden. Through the implementation of the model systems shortages of critical antibiotics can be circumvented and better availability of information leads to quicker reactions ability to stock outs of other antibiotics.
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Neurotoxicity of β-lactam antibiotics : experimental kinetic and neurophysiological studiesSchliamser, Silvia E. January 1988 (has links)
The neurotoxic potential of intravenous administered benzylpenicillin (BPC) was studied in rabbits with intact blood-CNS barriers and rabbits with experimental E. coli meningitis. At onset of epileptogenic EEG activity or seizures, serum, CSF and brain tissue were collected for assay of BPC. Based on the fact that, in tissues, BPC seems to remain extracellularly, brain concentrations of BPC were expressed as brain tissue fluid (BTF) levels, calculated as lOx the concentration in whole brain tissue. Neurotoxicity could be precipitated in all rabbits. In normal rabbits BTF levels of BPC were considerably higher than those in CSF indicating a better penetration across the blood-brain barrier (BBB). BPC penetrated better to CSF and BTF in meningitic rabbits than in normal controls, suggesting some degree of damage of the BBB concomitant with meningeal inflammation. E. coli meningitis did not increase the neurotoxicity of BPC. In control rabbits the intracistemal injection of saline resulted in some degree of pleocytosis. Unmanipulated animals are therefore preferable as controls. Epileptogenic EEG-changes was the most precise of the two variables used for demonstration of neurotoxicity. EEG-changes were therefore used as neurotoxicity criterion in the following rabbit experiments. To evaluate the effect of uraemia alone and uraemia plus meningitis on the neurotoxity of BPC in rabbits, cephaloridine was used to induce uraemia. Meningitis was induced by intracistemal inoculation of a cephalosporinresistant strain of E. cloacae. Untreated rabbits were used as controls. Uraemia resulted in increased BTF penetration of BPC, possibly explained by permeability changes in the BBB and/or decreased binding of BPC to albumin. Uraemia did not result in increased penetration of BPC into the CSF of non-meningitic rabbits. Uraemic non-meningitic rabbits had the highest BTF levels of BPC at the criterion, indicating that cephaloridine-induced renal failure increased the epileptogenic threshold in these rabbits. The combination of uraemia and meningitis increased the neurotoxicity of BPC since the criterion was reached at considerably lower BTF levels of BPC. Meningitis, either alone or together with uraemia, did not increase the neurotoxicity in comparison to control rabbits. Higher BTF levels of BPC were found in meningitic rabbits than in controls with intact blood-CNS barriers at onset of EEG-changes. In all groups of rabbits there was a pronounced variability of BPC levels in the CSF while the intra-group variations in BTF levels were much smaller. Thus, BTF and not CSF levels were decisive for the neurotoxicity of BPC. Using the same EEG-model, the neurotoxic potential of imipenem/cilastatin (I) and a new penem derivative, FCE 22101 were compared in a cross-over study. Both I and FCE 22101 were significantly more neurotoxic than BPC. While BTF levels of the three antibiotics could be detected in all tested rabbits, detectable CSF levels were only found in one of twelve rabbits treated with I or FCE 22101, indicating that BTF concentrations rather than CSF ones are decisive for neurotoxicity of ß-lactam antibiotics. The EEG-model used was found to be a suitable model for cross-over studies of intravenously administered antibiotics. Using the "silent-second" as EEG-threshold, a CNS interaction between intraperitoneally administered BPC and intravenous thiopental was demonstrated in rats. The most probably site for this interaction is the organic acid transport system out of the CNS. Thiopental distribution in the rat brain seemed to depend not only on its lipid solubility. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1988, härtill 5 uppsatser.</p> / digitalisering@umu
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