European regulations on the use of antibiotics in veterinary medicine.

Antimicrobial resistance endangers the successful combat of bacterial infections in humans and animals. The common use of antibiotic classes including those of high clinical value in human as well as veterinary medicine is a critical factor contributing to or suspected to promote the emergence of antibiotic resistance. New legal provisions laid down in veterinary drug legislations and related guidelines and advice are in force in the European Union to safeguard the effectiveness, accessibility and availability of antibiotics. Categorisation of antibiotics in classes of importance for treatment of infections of humans by the WHO was one of the first steps. This task is also undertaken for antibiotics for treatment of animals by the EMA's Antimicrobial Advice Ad Hoc Expert Group. The new veterinary Regulation (EU) 2019/6 has extended restrictions for use of some antibiotics in animals to a full ban of certain antibiotics. While some (but not all) antibiotic compounds not being authorized in veterinary medicine may still be used in companion animals more strict provisions were already applicable for treatment of food producing animal species. Distinct regulations are in place for the treatment of animals kept in large numbers in flocks. Initial regulations focussed on the protection of consumers from residues of veterinary drugs in food commodities, new regulations address prudent (not routinely) and responsible selection, prescription and use of antibiotics, and have improved the practicality for cascade use outside the terms of marketing authorisation. Mandatory recording of use of veterinary medicinal products for food safety reasons is extended to rules for veterinarians and owners or holders of animals to regularly report the use of antibiotics for the purpose of official surveillance of consumption. National sales data of antibiotic veterinary medicinal products have been collected on a voluntary basis until 2022 by ESVAC, which has created awareness of major differences between EU member states. A significant decline in sales was reported for third and fourth generation cephalosporines, polymyxins (colistin), and (fluoro)quinolones since the initiation in 2011.

Understanding the background and clinical significance of the WHO, WOAH, and EMA classifications of antimicrobials to mitigate antimicrobial resistance.

In Europe, the classification systems of the WHO, WOAH (founded as OIE), and EMA are the prevailing standard documents guiding the prudent use of antibiotic substances. While the WHO document "Critically important antimicrobials for human medicine" eponymously focusses on the use in humans, the other two documents, "OIE List of Antimicrobial Agents of Veterinary Importance" and "EMA Categorization of antibiotics for use in animals," concentrate exclusively on the prudent use of antibiotics in animals. One common purpose of these classification systems is to provide guidance in making sound decisions on the choice of antibiotics for treating humans as well as animals. Although the latest editions of these compendia refer to one another and bear a clear resemblance at the category levels, some of the substances are grouped into unequal classes. This review illustrates the specific perspectives of the three categorization systems under consideration. The arguments raised for different classifications between the WHO and the EMA are exemplified for amoxicillins without beta-lactamase inhibitors, macrolides, sulfonamides, and colistin. For the daily clinical use of antibiotics, veterinarians should consider the EMA document, and, under tentative circumstances, consult the OIE list.

Chemical characterization by GC-MS and in vitro activity against Candida albicans of volatile fractions prepared from Artemisia dracunculus, Artemisia abrotanum, Artemisia absinthium and Artemisia vulgaris.

BACKGROUND: A large number of essential oils is reported to have significant activity against Candida albicans. But the different chemical composition influences the degree of their activity. The intention of this study was to investigate the chemical composition and the activity against Candida albicans of volatile oils obtained from Artemisia dracunculus, A. abrotanum, A. absinthium and A. vulgaris (Asteraceae). The aim of the study was to identify new chemical compounds that have effect against C. albicans.The essential oils were obtained by hydrodistillation or extraction with dichloromethane (a new procedure we developed trying to obtain better, more separated compounds) from air dried above ground plant material and analyzed by GC-MS. Additionally commercial essential oils from the same species were tested. The Candida albicans inhibition studies were carried out by the paper disc diffusion method. RESULTS: The essential oils shared common components but presented differences in composition and showed variable antifungal activity. Davanone and derivatives thereof, compounds with silphiperfolane skeleton, estragole, davanone oil, ß-thujone, sabinyl acetate, herniarin, cis-chrysanthenyl acetate, 1,8-cineol, and terpineol were the main components of Artemisia volatiles. CONCLUSIONS: Among the volatile fractions tested those from A. abrotanum containing davanone or silphiperfolane derivatives showed the highest antifungal activity. The in vitro tests revealed that the Artemisia oils are promising candidates for further research to develop novel anti-candida drugs.

Thiolated chitosans: design and in vivo evaluation of a mucoadhesive buccal peptide drug delivery system.

PURPOSE: Intravenous application of pituitary adenylate cyclase-activating polypeptide (PACAP) has been identified as a promising strategy for the treatment of type 2 diabetes. To generate a more applicable formulation, it was the aim of this study to develop a sustained buccal delivery system for this promising therapeutic peptide. METHODS: 2-Iminothiolane was covalently bound to chitosan to improve the mucoadhesive and permeation-enhancing properties of chitosan used as drug carrier matrix. The resulting chitosan-4-thiobutylamidine conjugate was homogenized with the enzyme inhibitor and permeation mediator glutathione (gamma-Glu-Cys-Gly), Brij 35, and PACAP (formulation A). The mixture was lyophilized and compressed into flat-faced discs (18 mm in diameter). One formulation was additionally coated on one side with palm wax (formulation B). Tablets consisting of unmodified chitosan and PACAP (formulation C) or of unmodified chitosan, Brij 35, and PACAP (formulation D) served as controls. Bioavailability studies were performed in pigs by buccal administration of these test formulations. Blood samples were analyzed via an ELISA method. RESULTS: Formulations A and B led to an absolute bioavailability of 1%, whereas PACAP did not reach the systemic circulation when administered via formulations C and D. Moreover, in the case of formulations A and B, a continuously raised plasma level of the peptide drug being in the therapeutic range could be maintained over the whole period of application (6 h). Formulations A and B were removed by moderate force from the buccal mucosa after 6 h, whereas formulations C and D detached from the mucosa 4 h after application. CONCLUSION: The study reveals this novel mucoadhesive delivery system to be a promising approach for buccal delivery of PACAP.

The use of thiolated polymers as carrier matrix in oral peptide delivery--proof of concept.

It was the aim of this study to develop an oral delivery system for the peptide drug antide. The stability of the therapeutic peptide towards gastrointestinal peptidases was evaluated. The therapeutic agent and the permeation mediator glutathione were embedded in the thiolated polymer chitosan-4-thio-butylamidine conjugate (chitosan-TBA conjugate) and compressed to tablets. Drug release studies were performed in the dissolution test apparatus according to the Pharmacopoeia Europea using the paddle method and demineralized water as release medium. In order to avoid mucoadhesion of these delivery systems already in the oral cavity and oesophagus tablets were coated with a triglyceride. These tablets were orally given to pigs (weight: 50+/-2 kg; Edelschwein Pietrain). Moreover, antide was administered intravenously, subcutaneously and orally in solution. Results showed stability of antide towards pepsin, trypsin and chymotrypsin. In contrast, antide was rapidly degraded by elastase. Consequently a stomach-targeted delivery system was designed. Drug release studies demonstrated an almost zero-order controlled release of antide over 8 h. In vivo studies demonstrated a relative bioavailability of 34.4% for the subcutaneous administration. Oral administration of antide in solution led to no detectable concentrations of the drug in plasma at all. In contrast, administering antide being incorporated in the thiolated polymer resulted in a significant uptake of the peptide. The absolute and relative bioavailability was determined to be 1.1% and 3.2%, respectively.

Low dose magnetic fields do not cause oxidative DNA damage in human placental cotyledons in vitro.

The biological impact of low dose magnetic fields generated by electric appliances present in the human environment is still uncertain. In this study, human placentas served as a model tissue for the evaluation of the potential effect of oscillating low intensity magnetic fields on the concentration of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in cellular DNA. Cotyledons were dissected from placentas obtained immediately after physiological labours and exposed to magnetic fields (groups MF A, 2 mT, 50 Hz and MF B, 5 mT, 50 Hz) or sham exposed (group C) during an in vitro perfusion of 3 h. Cellular DNA was isolated, hydrolyzed and analyzed by HPLC. Native nucleosides were monitored at 254 nm and 8-OH-dG by electrochemical detection. Results were expressed as mumol 8-OH-dG/mol deoxyguanosine (dG). The concentrations of 8-OH-dG in group C, MF A and MF B were 28.45+/-15.27 micromol/mol dG, 62.80+/-31.91 mumol/mol dG, and 27.49+/-14.23 micromol/mol dG, respectively, demonstrating no significant difference between the groups. The results suggest that placental tissues possess a capacity to protect DNA against oxidative alterations by magnetic field of intensities previously shown to produce radical mediated DNA damage in rat brain cells in vivo and imbalances in electrolyte release of cotyledons under in vitro conditions.

Oxidative DNA damage in placentas from normal and pre-eclamptic pregnancies.

Placental oxidative stress was suggested to play a role in the pathogenesis of pre-eclampsia (PE). In this study, levels of 8-hydroxy-2'-deoxyguanosine (8-OH-dG), a well-established marker of oxidative DNA damage, were analysed in placental cellular DNA from normal (group NP) and pre-eclamptic (group PE) pregnancies as well as from PE pregnancies complicated by intrauterine growth restriction (group PE-IUGR). Placental samples obtained immediately after delivery were frozen at -80 degrees C until analysis. Cellular DNA was isolated, hydrolysed and analysed using high-performance liquid chromatography. Native nucleosides were monitored at 254 nm and 8-OH-dG using electrochemical detection. Concentrations of 8-OH-dG were expressed as micro mol/mol 2'-deoxyguanosine. In group NP, mean concentration of 8-OH-dG reached 179.97+/-80.58 (+/-SEM; micro mol/mol dG). 8-OH-dG levels were higher in group PE (273.44+/-110.14 micro mol/mol), but the difference was not significant in comparison with group NP. Highest concentrations of 8-OH-dG were found in group PE-IUGR (428.97+/-141.40 micro mol/mol), with levels significantly higher than in group NP, but not group PE. The results indicate a positive correlation between the severity of PE and the degree of oxidative stress and corroborate previous studies suggesting reactive oxygen species to be involved in the pathophysiology of PE.

[Oesophagogastroduodenoscopy in swine--technique, methods, indications]. / Osophagogastroduodenoskopie beim Schwein--Technik, Methode, Indikationen.

The aim of this study was to investigate in 20 healthy pigs the practicability of the oesophagogastroduodenoscopic examination technique in regard to equipment, method of examination, indications and its suitability as a diagnostical tool for the assessment of the oesophagus, stomach and upper duodenum in one procedure. Preparation of the patient for endoscopy, the procedure of the endoscopic examination as well as the topographical findings of the upper intestinal tract including the duodenum until the flexura duodenojejunalis are described. Flexible oesophagogastroduodenoscopy is a suitable method for the observation and natural visualisation of mucosal surfaces and for the digital documentation of peristaltic movements. The procedure is easy to perform in anaesthetized animals, is in most cases completed within 15 min, and can be repeated in the same animal. Indications of this interesting diagnostic imaging technique are discussed.