Free radical polymerization technique was used to formulate Poloxamer-188 based hydrogels for controlled delivery. A total of seven formulations were formulated with varying concentrations of polymer, monomer ad cross linker. In order to assess the structural properties of the formulated hydrogels, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning electron microscopy (SEM), and X-ray diffraction (XRD) were carried out. To assess the effect of pH on the release of the drug from the polymeric system, drug release studies were carried in pH 1.2 and 7.4 and it was found that release of the drug was significant in pH 7.4 as compared to that of pH 1.2 which confirmed the pH responsiveness of the system. Different kinetic models were also applied to the drug release to evaluate the mechanism of the drug release from the system. To determine the safety and biocompatibility of the system, toxicity study was also carried out for which healthy rabbits were selected and formulated hydrogels were orally administered to the rabbits. The results obtained suggested that the formulated poloxamer-188 hydrogels are biocompatible with biological system and have the potential to serve as controlled drug delivery vehicles.
- MeSH
- akrylové pryskyřice * chemie MeSH
- diferenciální skenovací kalorimetrie MeSH
- difrakce rentgenového záření MeSH
- hydrogely * chemie MeSH
- koncentrace vodíkových iontů MeSH
- králíci MeSH
- léky s prodlouženým účinkem chemie farmakokinetika MeSH
- mikroskopie elektronová rastrovací MeSH
- nosiče léků chemie MeSH
- poloxamer * chemie MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- systémy cílené aplikace léků MeSH
- termogravimetrie MeSH
- timolol * aplikace a dávkování farmakokinetika chemie MeSH
- uvolňování léčiv MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The treponemes infecting lagomorphs include Treponema paraluisleporidarum ecovar Cuniculus (TPeC) and ecovar Lepus (TPeL), infecting rabbits and hares, respectively. In this study, we described the first complete genome sequence of TPeL, isolate V3603-13, from an infected mountain hare (Lepus timidus) in Sweden. In addition, we determined 99.0% of the genome sequence of isolate V246-08 (also from an infected mountain hare, Sweden) and 31.7% of the genome sequence of isolate Z27 A77/78 (from a European hare, Lepus europeaus, The Netherlands). The TPeL V3603-13 genome had considerable gene synteny with the TPeC Cuniculi A genome and with the human pathogen T. pallidum, which causes syphilis (ssp. pallidum, TPA), yaws (ssp. pertenue, TPE) and endemic syphilis (ssp. endemicum, TEN). Compared to the TPeC Cuniculi A genome, TPeL V3603-13 contained four insertions and 11 deletions longer than three nucleotides (ranging between 6 and2,932 nts). In addition, there were 25 additional indels, from one to three nucleotides long, altogether spanning 36 nts. The number of single nucleotide variants (SNVs) between TPeC Cuniculi A and TPeL V3603-13 were represented by 309 nucleotide differences. Major proteome coding differences between TPeL and TPeC were found in the tpr gene family, and (predicted) genes coding for outer membrane proteins, suggesting that these components are essential for host adaptation in lagomorph syphilis. The phylogeny revealed that the TPeL sample from the European brown hare was more distantly related to TPeC Cuniculi A than V3603-13 and V246-08.
- MeSH
- fylogeneze * MeSH
- genom bakteriální MeSH
- králíci MeSH
- syfilis * mikrobiologie MeSH
- Treponema * genetika izolace a purifikace MeSH
- zajíci * mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Liposomes are one of the most important drug delivery vectors, nowadays used in clinics. In general, polyethylene glycol (PEG) is used to ensure the stealth properties of the liposomes. Here, we have employed hydrophilic, biocompatible and highly non-fouling N-(2-hydroxypropyl) methacrylamide (HPMA)-based copolymers containing hydrophobic cholesterol anchors for the surface modification of liposomes, which were prepared by the method of lipid film hydration and extrusion through 100 nm polycarbonate filters. Efficient surface modification of liposomes was confirmed by transmission electron microscopy, atomic force microscopy, and gradient ultracentrifugation. The ability of long-term circulation in the vascular bed was demonstrated in rabbits after i.v. application of fluorescently labelled liposomes. Compared to PEGylated liposomes, HPMA-based copolymer-modified liposomes did not induce specific antibody formation and did not activate murine and human complement. Compared with PEGylated liposomes, HPMA-based copolymer-modified liposomes showed a better long-circulating effect after repeated administration. HPMA-based copolymer-modified liposomes thus represent suitable new candidates for a generation of safer and improved liposomal drug delivery platforms.
- MeSH
- akrylamidy chemie MeSH
- aktivace komplementu účinky léků MeSH
- cholesterol chemie krev MeSH
- hydrofobní a hydrofilní interakce * MeSH
- králíci MeSH
- lidé MeSH
- liposomy * MeSH
- myši MeSH
- polyethylenglykoly * chemie MeSH
- polymery chemie MeSH
- povrchové vlastnosti * MeSH
- systémy cílené aplikace léků MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- antilymfocytární sérum * terapeutické užití MeSH
- aplastická anemie * farmakoterapie MeSH
- cyklosporin * terapeutické užití MeSH
- dítě MeSH
- imunosupresiva * terapeutické užití MeSH
- kojenec MeSH
- koně MeSH
- králíci MeSH
- lidé MeSH
- mladiství MeSH
- předškolní dítě MeSH
- retrospektivní studie MeSH
- výsledek terapie MeSH
- zvířata MeSH
- Check Tag
- dítě MeSH
- kojenec MeSH
- králíci MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- dopisy MeSH
- srovnávací studie MeSH
Anthracyclines, such as doxorubicin (adriamycin), daunorubicin, or epirubicin, rank among the most effective agents in classical anticancer chemotherapy. However, cardiotoxicity remains the main limitation of their clinical use. Topoisomerase IIβ has recently been identified as a plausible target of anthracyclines in cardiomyocytes. We examined the putative topoisomerase IIβ selective agent XK469 as a potential cardioprotective and designed several new analogs. In our experiments, XK469 inhibited both topoisomerase isoforms (α and β) and did not induce topoisomerase II covalent complexes in isolated cardiomyocytes and HL-60, but induced proteasomal degradation of topoisomerase II in these cell types. The cardioprotective potential of XK469 was studied on rat neonatal cardiomyocytes, where dexrazoxane (ICRF-187), the only clinically approved cardioprotective, was effective. Initially, XK469 prevented daunorubicin-induced toxicity and p53 phosphorylation in cardiomyocytes. However, it only partially prevented the phosphorylation of H2AX and did not affect DNA damage measured by Comet Assay. It also did not compromise the daunorubicin antiproliferative effect in HL-60 leukemic cells. When administered to rabbits to evaluate its cardioprotective potential in vivo, XK469 failed to prevent the daunorubicin-induced cardiac toxicity in either acute or chronic settings. In the following in vitro analysis, we found that prolonged and continuous exposure of rat neonatal cardiomyocytes to XK469 led to significant toxicity. In conclusion, this study provides important evidence on the effects of XK469 and its combination with daunorubicin in clinically relevant doses in cardiomyocytes. Despite its promising characteristics, long-term treatments and in vivo experiments have not confirmed its cardioprotective potential.
- MeSH
- antibiotika antitumorózní toxicita MeSH
- antracykliny * toxicita terapeutické užití MeSH
- chinoxaliny * MeSH
- daunomycin toxicita terapeutické užití MeSH
- DNA-topoisomerasy typu II metabolismus terapeutické užití MeSH
- doxorubicin toxicita MeSH
- inhibitory topoisomerasy II * toxicita terapeutické užití MeSH
- kardiotoxicita MeSH
- králíci MeSH
- krysa rodu rattus MeSH
- poškození DNA MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Throughout human evolutionary history, snakes have been associated with danger and threat. Research has shown that snakes are prioritized by our attentional system, despite many of us rarely encountering them in our daily lives. We conducted two high-powered, pre-registered experiments (total N = 224) manipulating target prevalence to understand this heightened prioritization of threatening targets. Target prevalence refers to the proportion of trials wherein a target is presented; reductions in prevalence consistently reduce the likelihood that targets will be found. We reasoned that snake targets in visual search should experience weaker effects of low target prevalence compared to non-threatening targets (rabbits) because they should be prioritized by searchers despite appearing rarely. In both experiments, we found evidence of classic prevalence effects but (contrasting prior work) we also found that search for threatening targets was slower and less accurate than for nonthreatening targets. This surprising result is possibly due to methodological issues common in prior studies, including comparatively smaller sample sizes, fewer trials, and a tendency to exclusively examine conditions of relatively high prevalence. Our findings call into question accounts of threat prioritization and suggest that prior attention findings may be constrained to a narrow range of circumstances.
Background: Gingiva is a delicate tissue that protects alveolar bone against external stimuli. Gingival breaks expose alveolar bone, and the fast wounds heal the betterment of the teeth frame. We aimed to compare the influence of omega-3 on the gingival healing period after trauma and the potential involvement of cytokeratin-19 protein expression.Methods: A total of 18 rabbits were used, after trauma-induced, these rabbits were subdivided into three groups of 6 each. Group 1 is the control group that received normal saline only, the second group received omega 3 for 10 days before the trauma, while the third group received omega 3 supplements for 10 days before the gingival injury and continued receiving them for an additional 10 days afterwards. For each time point (third and seventh day of healing), 3 rabbits were sacrificed, and tissue was collected for total antioxidant capacity and malondialdehyde measurement. Tissue fixed for histopathology and immunohistochemistry analysis.Results: Omega 3 has shown improvement in the healing process regarding the period of healing, antioxidant parameters, and intensity of cytokeratin-19 expression compared to the control group. Moreover, rabbit groups exposed to omega 3 before trauma has shown better healing response compared to those initiated therapy with trauma.Conclusion: Omega 3 is notably beneficial when used for both prevention and treatment since it reduces oxidative stress and improves healing processes measured by increased expression of cytokeratin-19 in epithelial tissue. Omega 3 can therefore be thought of as a possible choice for the treatment of gingival wounds and gingivitis.
Background: After injuries, infections, or tumor removal, endogenous healing depends on bone repair. Disorders of bone healing are difficult to treat in clinical settings. There are numerous induced methods for correcting bone abnormalities, such as the induced membrane technique, allogenic bone grafting, synthetic bone grafting, artificial joint replacement, and autologous bone grafting. However, the delivery of the bone graft and bone filling materials necessitates surgical implantation at the fracture site, which could cause edema, infection, and the development of heterotopic bone locally. Therefore, systemically administered osteogenic drugs will provide an excellent method for bone lesion healing. Aim of the study: to evaluate the systemic effect of metformin on bone healing after surgical induction of bony defect and to determine the amount of newly formed bone using histological, histomorphometric analysis, and the surface area measurement of newly formed bone. Also to study the safety of metformin administration at the administered dose for this purpose. Materials and methods: Twenty mature male New Zealand rabbits were separated into two groups, each including ten rabbits for the study. The same surgical procedure was performed on all rabbits. Two holes were made at the femur (3 mm in diameter and 3 mm in depth) and left empty. Metformin tablets were ground into a fine powder and the resultant powder was dissolved in 10ml of water to prepare a liquid dosage containing 50 mg /1ml of metformin. Metformin is administered orally to the rabbits through a feeding tube at a dose of 50 mg/kg body weight. Animals were euthanized at two-time intervals, 14 and 28 days. The femur was separated, sectioned preserved, and sent for histological analysis and histomor-phometry. Results: The results revealed that there is an increase in new bone formation and bone-forming cells in the metformin-treated group. Conclusion: Metformin increases bone healing by increasing the number of bone-forming cells and the surface area of newly formed bone tissues and causes less inflammatory response at the site of a bone lesion. So it possesses an osteogenic effect.
PURPOSE OF THE STUDY: The preclinical study aimed to compare the healing of segmental bone defects treated with biodegradable hyaluronic acid and tricalcium phosphate-based hydrogel with the established autologous spongioplasty. Another aim was to evaluate the hydrogel as a scaffold for osteoinductive growth factor of bone morphogenetic protein-2 (BMP-2) and stem cells. MATERIAL AND METHODS: The study was conducted in an in vivo animal model. A standardized rabbit model of a 15 mm long segmental bone defect of left radius was used. A total of 40 animals were divided into 5 groups of 8 individuals. In the KO- (negative control) group, the created defect was left to heal spontaneously. In the KO+ (positive control) group, the defect was filled with morselized bone autograft prepared from the resected segment. In the study group A, the defect was filled with hydrogel based on hyaluronic acid derivative and tricalcium phosphate. In the study group B, the defect was filled with hydrogel based on hyaluronic acid derivative, tricalcium phosphate and bone marrow aspirate. In the study group C, the defect was filled with hydrogel based on hyaluronic acid derivative, tricalcium phosphate, bone marrow aspirate and BMP-2. Healing was assessed using radiographs at 1, 6, and 12 weeks postoperatively and histology specimens were collected at 16 weeks postoperatively. RESULTS: Altogether 35 rabbits survived (KO- 7, KO+ 7, A 7, B 6, C 8) until the end of the study. As concerns the radiographic assessment, the best results were achieved by the groups KO+ and C, where new bone formation across the entire width of the bone defect was clearly seen at 6 and 12 weeks and the osteotomy line was completely healed too. At 12 weeks, complete bone remodelling was observed in all animals in the group KO+, whereas in the group C, bone remodelling was fully completed in 5 animals and partially completed in 3 animals. In terms of histological assessment, however, the best results were achieved by the group C, where the bone defect was completely remodelled into lamellar bone in 7 specimens, while in 1 specimen it healed with bony callus formation. In the group KO+, the defect was healed in 4 specimens by cartilaginous callus with loci of remodelling into bony callus, in 2 specimens the bony callus was predominant with cartilaginous callus areas, and only one defect was completely remodelled into lamellar bone. DISCUSSION: Compared to autografts that manifest osteogenic, osteoinductive and osteoconductive properties, the biodegradable hyaluronic acid and tricalcium phosphate-based hydrogel has osteoconductive properties only. Thus, it was also tested in our study as a scaffold for bone marrow cells and BMP-2 osteoinductive growth factor. Thanks to its semi-liquid properties, the biodegradable hyaluronic acid and tricalcium phosphate-based hydrogel is a promising material for use in 3D printing. CONCLUSIONS: The preclinical study in an in vivo animal model confirmed the beneficial effect of the biodegradable hyaluronic acid and tricalcium phosphate-based hydrogel on the healing of critical-size segmental bone defects. Better healing of these defects was also confirmed for filling composed of hydrogel and BMP-2 osteoinductive growth factor. The benefit of bone marrow aspirate mixed with hydrogel was not confirmed. KEY WORDS: bone defect, non-union, rabbit, hyaluronic acid, calcium phosphate, stem cells, BMP-2, scaffold, bone healing, spongioplasty.
- MeSH
- fosforečnany vápenaté * farmakologie MeSH
- hydrogely farmakologie MeSH
- kostní morfogenetický protein 2 * MeSH
- králíci MeSH
- kyselina hyaluronová * farmakologie MeSH
- modely nemocí na zvířatech MeSH
- radius chirurgie zranění MeSH
- regenerace kostí účinky léků MeSH
- tkáňové podpůrné struktury * MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
Kokcidióza patří mezi nejčastější onemocnění králíků v době odstavu a je jedním z limitujících faktorů odchovu králíků. Mezi patogenní kokcidie řadíme u králíků druhy parazitující ve střevech (E. magna, E. irresidua, E. intestinalis, E. flavescens, E. piriformis, a E. media) a jaterní kokcidie (E. stiedae). Stupeň infekce je závislý na druhu Eimerie, množství pozřených oocyst, věku a imunitním stavu hostitele. Diagnostika je založena na flotačním vyšetření, případně na přesném určení druhu pomocí molekulárněbiologických metod. Terapie spočívá v aplikaci antikokcidik (sulfonamidů, toltrazurilu) ve vodě nebo podaných přímo do dutiny ústní. Prevence onemocnění spočívá v dobrých zoohygienických podmínkách, správně provedeném odstavu, krmné dávce a jejím složení (v obsahu vlákniny, škrobů a bílkovin), snížení stresových faktorů a v případě velkochovů nebo malochovů v podání peletovaného krmiva s obsahem kokcidiostatik.
Coccidiosis is one of the most common diseases of rabbits at the time of weaning and is one of the limiting factors in rabbit breeding. Pathogenic coccidia in rabbits includes species parasitizing in the intestines (E. magna, E. irresidua, E. intestinalis, E. flavescens, E. piriformis, and E. media) and liver (E. stiedae). The severity of infection depends on the species of Eimeria, the number of ingested oocysts, age, and immune status of the host. Diagnostics is based on a flotation examination, or the exact determination of the species using molecular biological methods. Therapy consists of the oral administration of anticoccidials (sulphonamides, toltrazuril) in water or directly into the oral cavity. Disease prevention consists of optimal zoohygiene, properly performed weaning, feed ration and its composition (fiber, starch, and protein content), reduction of stress factors, and, in the case of large-scale or small-scale farms, in the form of pelleted diets containing coccidiostatics.
