Evaluation of Angiogenesis in an Acellular Porous Biomaterial Based on Polyhydroxybutyrate and Chitosan Using the Chicken Ex Ovo Chorioallantoic Membrane Model

Simple Summary

The chorioallantoic membrane (CAM) is an avian extraembryonic membrane widely used as an experimental assay to study angiogenesis and its inhibition in response to tissues, cells, or soluble factors. In recent years, the CAM has become popular in scientific studies focused on the use of its potential for the study of biocompatibility of materials for regenerative strategies and tissue engineering applications. Great research efforts are being made to develop innovative biomaterials able to treat hard tissue defects, including diseases such as a bone cancer. In this article, we describe an approach to detect the formation of blood vessels inside the porous acellular biopolymer polyhydroxybutyrate/chitosan (PHB/CHIT) scaffold using the CAM assay as an in vivo alternative animal model, including macroscopic, histological, immunohistochemical, and molecular evaluation of the biocompatibility.

Abstract

The chorioallantoic membrane (CAM) is a highly vascularized avian extraembryonic membrane widely used as an in vivo model to study angiogenesis and its inhibition in response to tissues, cells, or soluble factors. In recent years, the use of CAM has become an integral part of the biocompatibility testing process for developing biomaterials intended for regenerative strategies and tissue engineering applications. In this study, we used the chicken ex ovo CAM assay to investigate the angiogenic potential of innovative acellular biopolymer polyhydroxybutyrate/chitosan (PHB/CHIT) scaffold, which is intended for the treatment of hard tissue defects, depending on treatment with pro- and anti-angiogenic substances. On embryonic day (ED) 7, the experimental biomaterials were placed on the CAM alone or soaked in vascular endothelial growth factor (VEGF-A), saline solution (PHY), or tyrosine kinase inhibitor (SU5402). After 72 h, the formation of vessels was analyzed in the surrounding area of the scaffold and inside the pores of the implants, using markers of embryonic endothelium (WGA, SNA), myofibroblasts (α-SMA), and macrophages (KUL-01). The morphological and histochemical analysis showed strong angiogenic potential of untreated scaffolds without additional effect of the angiogenic factor, VEGF-A. The lowest angiogenic potential was observed in scaffolds soaked with SU5402. Gene expression of pro-angiogenic growth factors, i.e., VEGF-A, ANG-2, and VE-CAD, was upregulated in untreated scaffolds after 72 h, indicating a pro-angiogenic environment. We concluded that the PHB/CHIT has a strong endogenous angiogenic potential and could be promising biomaterial for the treatment of hard tissue defects.

In Vivo Study of Osteochondral Defect Regeneration Using Innovative Composite Calcium Phosphate Biocement in a Sheep Model

This study aimed to clarify the therapeutic effect and regenerative potential of the novel, amino acids-enriched acellular biocement (CAL) based on calcium phosphate on osteochondral defects in sheep. Eighteen sheep were divided into three groups, the treated group (osteochondral defects filled with a CAL biomaterial), the treated group with a biocement without amino acids (C cement), and the untreated group (spontaneous healing). Cartilages of all three groups were compared with natural cartilage (negative control). After six months, sheep were evaluated by gross appearance, histological staining, immunohistochemical staining, histological scores, X-ray, micro-CT, and MRI. Treatment of osteochondral defects by CAL resulted in efficient articular cartilage regeneration, with a predominant structural and histological characteristic of hyaline cartilage, contrary to fibrocartilage, fibrous tissue or disordered mixed tissue on untreated defect (p < 0.001, modified O'Driscoll score). MRI results of treated defects showed well-integrated and regenerated cartilage with similar signal intensity, regularity of the articular surface, and cartilage thickness with respect to adjacent native cartilage. We have demonstrated that the use of new biocement represents an effective solution for the successful treatment of osteochondral defects in a sheep animal model, can induce an endogenous regeneration of cartilage in situ, and provides several benefits for the design of future therapies supporting osteochondral defect healing.

Dimethyl Sulfoxide: Morphological, Histological, and Molecular View on Developing Chicken Liver

Dimethyl sulfoxide (DMSO) is widely used as a solvent for small hydrophobic drug molecules. However, the safe volume allowing to avoid its embryotoxic effect has been poorly studied. In this study, we documented the effects of dimethyl sulfoxide (DMSO) in the developing chicken embryo at morphological, histological, and molecular levels. We focused on the developing chicken liver as the main organ involved in the process of detoxification. In our study, 100% DMSO was administered subgerminally onto the eggshell membrane (membrana papyracea) at various volumes (5, 10, 15, 20, 25, 30, 35, and 50 µL) on 4th embryonic day (ED). We focused on histopathological alterations of the liver structure, and noticed the overall impact of DMSO on developing chicken embryos (embryotoxicity, malformation). At the molecular level, we studied cytochrome P450 complex (CYP) isoform's activities in relation to changes of CYP1A5, CYP3A37, and CYP3A80 gene expression. Total embryotoxicity after application of different doses of DMSO on ED 4, and the embryo lethality increased with increasing DMSO amounts. Overall mortality after DMSO administration ranged below 33%. Mortality was increased with higher amounts of DMSO, mainly from 20 µL. The highest mortality was observed for the highest dose of DMSO over 35 µL. The results also showed a decrease in body weight with increased application volumes of DMSO. At the histological level, we observed mainly the presence of lipid droplets and dilated bile canaliculi and sinusoids in samples over the administration of 25 µL of DMSO. While these findings were not statistically significant, DMSO treatment caused a significant different up-regulation of mRNA expression in all studied genes. For CYP1A5, CYP3A37, and CYP3A80 DMSO volumes needed were 15 µL, 10 µL, and 20 µL, respectively. A significant down-regulation of all studied CYP isoform was detected after application of a DMSO dose of 5 µL. Regarding the morphological results, we can assume that the highest safe dose of DMSO without affecting chicken embryo development and its liver is up to 10 µL. This conclusion is corroborated with the presence of number of malformations and body weight reduction, which correlates with histological findings. Moreover, the gene expression results showed that even the lowest administered DMSO volume could affect hepatocytes at the molecular level causing down-regulation of cytochrome P450 complex (CYP1A5, CYP3A37, CYP3A80).

Potential Effect of Pseudevernia furfuracea (L.) Zopf Extract and Metabolite Physodic Acid on Tumour Microenvironment Modulation in MCF-10A Cells

Lichens comprise a number of unique secondary metabolites with remarkable biological activities and have become an interesting research topic for cancer therapy. However, only a few of these metabolites have been assessed for their effectiveness against various in vitro models. Therefore, the aim of the present study was to assess the effect of extract Pseudevernia furfuracea (L.) Zopf (PSE) and its metabolite physodic acid (Phy) on tumour microenvironment (TME) modulation, focusing on epithelial–mesenchymal transition (EMT), cancer-associated fibroblasts (CAFs) transformation and angiogenesis. Here, we demonstrate, by using flow cytometry, Western blot and immunofluorescence microscopy, that tested compounds inhibited the EMT process in MCF-10A breast cells through decreasing the level of different mesenchymal markers in a time- and dose-dependent manner. By the same mechanisms, PSE and Phy suppressed the function of Transforming growth factor beta (TGF-β)-stimulated fibroblasts. Moreover, PSE and Phy resulted in a decreasing level of the TGF-β canonical pathway Smad2/3, which is essential for tumour growth. Furthermore, PSE and Phy inhibited angiogenesis ex ovo in a quail embryo chorioallantoic model, which indicates their potential anti-angiogenic activity. These results also provided the first evidence of the modulation of TME by these substances.

Changes in the Acute-Phase Protein Concentrations and Activities of Some Enzymes in Pigs Following the Repair of Experimentally Induced Articular Cartilage Defects Using Two Types of Biocement Powder

Simple Summary

Articular cartilage reconstruction is aimed at the restoration of damaged joint cartilage. The use of bone cement is one type of method applicable for this reconstruction. The potential use of repair techniques must be evaluated by pre-clinical and clinical studies in animal models, including the assessment of some biochemical parameters. Acute-phase proteins are a class of proteins whose concentrations increase in response to injury or inflammation. They may serve as useful biomarkers for the evaluation of post-operative complications, as well as to reflect the extent of surgical trauma. Information regarding their usefulness after cartilage reconstruction are still limited. Similarly, little is known about the response of the organism to various reconstruction techniques and various biomaterials used for the repair of defects. This paper provides important information about the changes in the concentrations of acute-phase proteins and the activity of serum enzymes in pigs within the first 30 days following the repair of experimentally induced articular cartilage defects using tetracalcium phosphate/nanomonetite cement powder (C cement) and cement powder containing aminoacids (CAK cement). Marked inflammatory responses with increased acute-phase proteins concentrations were observed following the reconstruction of articular cartilage defects using both types of biocement powder. The results suggest, that the tetracalcium phosphate/nanomonetite cement powder without amino acids would be more suitable for possible cartilage repair in the human population.

Abstract

The objective of the study was to assess the usefulness of acute-phase proteins (APPs) and serum enzymes in the evaluation of post-operative state after cartilage reconstruction in an animal model (Sus scrofa domesticus). Fifteen clinically healthy female pigs were evaluated during the first 30 days after the repair of experimentally induced articular cartilage defects using two types of biocement powders. Animals were divided into groups according to the type of biocement powder used: CAK—with amino acids (n = 6), C—without amino acids (n = 6) and the control group (Ctr) was without biocement (n = 3). The concentrations of selected APPs—serum amyloid A (SAA), haptoglobin (Hp) and C-reactive protein (CRP), and the activities of some serum enzymes—creatine kinase (CK), alkaline phosphatase (AP), and lactate dehydrogenase (LD) were measured one day before the surgery and on days 7, 14, and 30 after the surgical intervention. The most significant changes during the evaluated period were observed in the concentrations of SAA (p < 0.001) and Hp (p < 0.001), with marked increase of values 7 days after surgery. There was a numerical, but not statistically significant, difference between CAK, C and Ctr groups (p > 0.05). Marked variations were observed also in the activities of the evaluated enzymes, with the most significant changes in the activity of AP in the CAK group (p < 0.001). Presented results suggest possible usefulness of some APPs and serum enzymes in the evaluation of post-operative inflammatory state after the reconstruction of articular cartilage defects.

Canine Bone Marrow-derived Mesenchymal Stem Cells: Genomics, Proteomics and Functional Analyses of Paracrine Factors

Adult stem cells have become prominent candidates for treating various diseases in veterinary practice. The main goal of our study was therefore to provide a comprehensive study of canine bone marrow-derived mesenchymal stem cells (BMMSC) and conditioned media, isolated from healthy adult dogs of different breeds. Under well-defined standardized isolation protocols, the multipotent differentiation and specific surface markers of BMMSC were supplemented with their gene expression, proteomic profile, and their biological function. The presented data confirm that canine BMMSC express important genes for differentiation toward osteo-, chondro-, and tendo-genic directions, but also genes associated with angiogenic, neurotrophic, and immunomodulatory properties. Furthermore, using proteome profiling, we identify for the first time the dynamic release of various bioactive molecules, such as transcription and translation factors and osteogenic, growth, angiogenic, and neurotrophic factors from canine BMMSC conditioned medium. Importantly, the relevant genes were linked to their proteins as detected in the conditioned medium and further associated with angiogenic activity in chorioallantoic membrane (CAM) assay. In this way, we show that the canine BMMSC release a variety of bioactive molecules, revealing a strong paracrine component that may possess therapeutic potential in various pathologies. However, extensive experimental or preclinical trials testing canine sources need to be performed in order to better understand their paracrine action, which may lead to novel therapeutic strategies in veterinary medicine.

3D Reconstruction and Evaluation of Accessory Hepatic Veins in Right Hemilivers in Laboratory Animals by Metrotomography: Implications for Surgery

Background

The current study investigated the detection of accessory hepatic veins and their vascular territories in the right hemiliver in rats, guinea pigs, and rabbits, which has become a prerequisite for newly developed clinical procedures. We compared the anatomical continuity of accessory hepatic veins with accessory hepatic veins existing in human livers.

Material/Methods

The analysis of accessory hepatic veins was performed using a corrosion cast method in combination with computer tomography (CT).

Results

In normal livers, accessory hepatic veins were regularly found. The length of these veins was 0.88±0.29 (cm ±SD) in rats, 1.10±0.39 in guinea pigs, and 1.28±0.48 in rabbits. Accessory hepatic veins became a part of the draining vessel draining into segment VI and VII; represented by interpolating and following Chouinard’s segmental concept.

Conclusions

The importance of detecting accessory hepatic veins lies in the identification of structures requiring special attention during surgery, in reduction of surgical complications, and in choosing the best approach to maintain the vitality of a drainage segment. The vascular reconstruction should be done during surgical interventions.

The Serum Protein Profile and Acute Phase Proteins in the Postoperative Period in Sheep after Induced Articular Cartilage Defect

Although several new implants have been developed using animal studies for the treatment of osteochondral and cartilage defects, there is a lack of information on the possible metabolic and biochemical reactions of the body to the implantation of biomaterials and cartilage reconstruction. Therefore, this study was aimed at evaluating the serum protein pattern and the alterations in the concentrations of selected acute phase proteins in five clinically healthy female sheep before and after the reconstruction of experimentally induced articular cartilage defects using polyhydroxybutyrate/chitosan based biopolymer material. The concentrations of total serum proteins (TSP), protein fractions, and selected acute phase proteins-serum amyloid A (SAA), haptoglobin (Hp), and C-reactive protein (CRP)-were measured before and on days seven, 14, and 30 after the surgical intervention. The TSP concentrations showed no marked differences during the evaluated period. Albumin values decreased on day seven and day 14 after surgery. In the concentrations of α₁-, α₂-, β-, and γ₂-globulins, a gradual significant increase was observed during the postoperative period (p < 0.05). The γ₁-globulins decreased slightly seven days after surgery. The concentrations of SAA, Hp, and CRP increased significantly after the surgical intervention with a subsequent decrease on day 30. Presented results suggest marked alterations in the serum protein pattern after surgical intervention.

Preclinical alternative model for analysis of porous scaffold biocompatibility in bone tissue engineering

Using scaffolds with appropriate porosity represents a potential approach for repair of critical-size bone defects. Vascularization is essential for bone formation and healing. This study investigates methods for monitoring angiogenesis within porous biopolymer scaffolds on the basis of polyhydroxybutyrate (PHB)/chitosan. We use the chick and quail chorioallantoic membrane (CAM) assay as an in vivo model focused on the formation of new blood vessels inside the implant structure. Chemical properties of the surface in biopolymer scaffold matrix were characterized as well as the tissue reaction of the CAM. Implantation of a piece of polymer scaffold results in vascular reaction, documented visually and by ultrasound biomicroscopy. Histological analysis shows myofibroblast reaction (smooth muscle actin-positive cells) without excessive collagen deposition. Cell invasion is observed inside the implant, and QH1 marker, detecting hemangioblasts and endothelial cells of quail origin, confirms the presence of vascular network. The CAM assay is a rapid and easy way to test biocompatibility and vasculogenic potential of new candidate scaffolds for bone tissue bioengineering with respect to the 3R´ s.

Dynamics of Evans blue clearance from cerebrospinal fluid into meningeal lymphatic vessels and deep cervical lymph nodes

Objectives Recently, it has been confirmed, that excess fluid and waste products from the brain are drained into the cerebrospinal fluid (CSF) and afterwards cleared via the olfactory route and/or lymphatic vessels in the brain dura and corresponding extracranial lymphatic structures. Therefore, the aim of present study was to monitor time-dependent uptake of Evans blue (EB) tracer from subarachnoid space into the meningeal lymphatic vessels and extracranial lymph nodes in rats during 3 hours-12 days. Methods EB was injected into the cisterna magna of anesthetized rats and after required survival, plasma, brain dura matter and corresponding lymph nodes (cervical, thoracic and lumbar) were dissected and processed for lymphatic vessels analyses using immunofluorescence and immunohistochemistry. Furthermore, we have used sensitive ultra-high-performance liquid chromatography (UHPLC) method for the determination of EB concentrations in selected samples. Results Using a combination of imaging methods, we have detected two different types of the vascular structures in the brain dura and in deep cervical lymph nodes. The blood vessels, which were RECA-1 + positive and the lymphatic-like vessels, expressing bright intense red fluorescence of EB tracer. Subsequently, using UHPLC with UV detection, we have quantified the EB concentration in positive structures by 3 hours up to 12 days after tracer delivery. A significant increase of EB concentration was detected in deep cervical lymph nodes already at 3 hours with a peak at 1 day that decreased to about one-tenth of its peak value by 12 days. Similar pattern was detected in brain dura. On the contrary, the brain tissue and plasma were almost negative for EB tracer during all tested time periods. Conclusion Our results demonstrate the dynamic changes of EB in meningeal lymphatic vessels and in deep cervical lymph nodes, thus recapitulating the downstream outflow of intracisternally injected tracer during 3 hours-12 days via dura mater lymphatic vessels towards corresponding extracranial draining system, particularly the deep cervical lymph nodes.

Brain-Cortex Microglia-Derived Exosomes: Nanoparticles for Glioma Therapy

The function and integrity of the nervous system require interactive exchanges among neurons and glial cells. Exosomes and other extracellular vesicles (EVs) are emerging as a key mediator of intercellular communication, capable of transferring nucleic acids, proteins and lipids influencing numerous functional and pathological aspects of both donor and recipient cells. The immune response mediated by microglia-derived exosomes is most prominently involved in the spread of neuroinflammation, neurodegenerative disorders, and brain cancer. Therefore, in the present study we describe a reproducible and highly efficient method for yielding purified primary microglia cells, followed by exosome isolation and their characterization. An in vitro biological assay demonstrates that microglia-derived exosomes tested on a 3D spheroid glioma culture were able to inhibit tumor invasion in time course. These results evidence that brain microglia-derived exosomes could be used as nanotherapeutic agents against glioma cells.

Comparative Genomics of Bacillus amyloliquefaciens Strains Reveals a Core Genome with Traits for Habitat Adaptation and a Secondary Metabolites Rich Accessory Genome

The Gram positive, non-pathogenic endospore-forming soil inhabiting prokaryote Bacillus amyloliquefaciens is a plant growth-promoting rhizobacterium. Bacillus amyloliquefaciens processes wide biocontrol abilities and numerous strains have been reported to suppress diverse bacterial, fungal and fungal-like pathogens. Knowledge about strain level biocontrol abilities is warranted to translate this knowledge into developing more efficient biocontrol agents and bio-fertilizers. Ever-expanding genome studies of B. amyloliquefaciens are showing tremendous increase in strain-specific new secondary metabolite clusters which play key roles in the suppression of pathogens and plant growth promotion. In this report, we have used genome mining of all sequenced B. amyloliquefaciens genomes to highlight species boundaries, the diverse strategies used by different strains to promote plant growth and the diversity of their secondary metabolites. Genome composition of the targeted strains suggest regions of genomic plasticity that shape the structure and function of these genomes and govern strain adaptation to different niches. Our results indicated that B. amyloliquefaciens: (i) suffer taxonomic imprecision that blurs the debate over inter-strain genome diversity and dynamics, (ii) have diverse strategies to promote plant growth and development, (iii) have an unlocked, yet to be delimited impressive arsenal of secondary metabolites and products, (iv) have large number of so-called orphan gene clusters, i.e., biosynthetic clusters for which the corresponding metabolites are yet unknown, and (v) have a dynamic pan genome with a secondary metabolite rich accessory genome.

Morphometric alterations, steatosis, fibrosis and active caspase-3 detection in carbamate bendiocarb treated rabbit liver

Increasing use of pesticides all over the world makes it necessary to reveal the toxic risk in populations of nontargeted organisms. Bendiocarb is one of the 12 insecticides recommended by the World Health Organization for use in malaria control in Africa, and is used against a variety of insects. The liver has an important role in its process of detoxication and excretion. In our experiment 56 adult rabbits of breed HY+, 28 males and 28 females were used. Animals were divided into groups (control, days 10, 20, 30 of bendiocarb administration). The presence of many binucleated hepatocytes, the highest number of liver cells and their decreased size at 10 day after bendiocarb administration was observed as an evidence of the hepatic regeneration. After the long-term treatment pronounced changes were presented such as vacuolization and dilatation of hepatocytes, dilatation of sinusoids between hepatocytes, and focal infiltration of inflammatory cells. Numerous cells with caspase-3 activity were present throughout the organ, most commonly around the portal tract and close to the central vein. Short and long-term bendiocarb treatment showed the central vein thickened rim with increased deposition of collagen, spreading of collagen fibers into the perisinusoidal, and pericellular space surrounding the central veins, and septal fibrosis extended from the portal tract. Subsequently, presence of the lipid vacuoles both in the liver parenchyma and inner of the hepatocytes were observed. These results suggest that bendiocarb treatment leads to increased cell death, liver perisinusoidal fibrosis, and steatosis, especially during the long-term administration.

Anatomical study of the arterial blood supply to the thoracolumbar spinal cord in guinea pig

Guinea pigs are frequently used as experimental models in studies of ischemic spinal cord injury. The aim of this study was to describe the arterial blood supply to the thoracolumbar spinal cord in 20 adult English self guinea pigs using the corrosion and dissection techniques. The dorsal intercostal arteries arising from the dorsal surface of the thoracic aorta were found as follows: in eight pairs in 70% of cases, in seven pairs in 20% of cases and in nine pairs in 10% of cases. Paired lumbar arteries were present as seven pairs in all the cases. The occurrence of the ventral and dorsal branches of the spinal rami observed in the thoracic and lumbar region was higher on the left than on the right. The artery of Adamkiewicz was present in 60% of cases as a single vessel and in 40% of cases as a double vessel. On the dorsal surface of the spinal cord, we found two dorsal spinal arteries in 60% of cases and three in 40% of cases. The presence of the artery of Adamkiewicz and nearly regular segmental blood supplying the thoracolumbar part of the spinal cord in all our studied animals is the reason for using guinea pigs as a simple model of ischemic damage to the thoracolumbar part of the spinal cord.

Arterial peculiarities of the thoracolumbar spinal cord in rabbit

The aim of this study was to investigate the arterial blood supply of the thoracolumbar spinal cord in rabbit. The study was carried out on twenty adult New Zealand white rabbits. Ten rabbits were used in the corrosion technique and ten rabbits in the dissection technique. After the killing, the vascular network was perfused with saline. Batson's corrosion casting kit no. 17 © was used as a casting medium. After polymerisation of the medium, in ten rabbits the maceration was carried out in KOH solution, and in ten other rabbits, formaldehyde was injected by the dissection technique into the vertebral canal. We found high variability of segmental arteries supplying blood to the spinal cord. There are 12 intercostal arteries and 1 costo-abdominal artery. Dorsal branches arising from the dorsal surface of the aorta thoracica were found as follows: in 70% of the cases, 9 pairs were present; in 20% of the cases 8 pairs; and in 10% of the cases 10 pairs. The paired arteriae lumbales were present in 6 pairs in 90% of the cases and in 5 pairs in 10% of the cases. On the dorsal surface of spinal cord, we found two irregular longitudinal arteries in 70% of the cases, no longitudinal arteries in 20% of the cases and three irregular longitudinal arteries in 10% of the cases receiving dorsal branches of rami spinales. Among the dorsal branches observed in the thoracic region, 60.5% were left-sided, 39.5% right-sided and in the lumbar region, 52.5% were left-sided and 47.5% right-sided.

Changes of the immunological and haematological parameters in rabbits after bendiocarbamate application

The effect of bendiocarbamate application (5 mg/kg b.w.) on the haematological and immunological parameters in rabbits was evaluated. Total leukocyte cell count, erythrocyte cell count, differential cell count were determined during the period of three months of bendiocarbamate application and compared with those in healthy animals. The immunotoxic effect was evaluated by the test of ingestion ability of phagocytes (phagocytic activity and index of phagocytic activity) and proliferation activity of lymphocytes after mitogen stimulation. The significant decrease of total leukocytes, lymphocytosis and neutropaenia were found after bendiocarbamate application. The functional activities of phagocytes (expressed as phagocytic activity) and lymphocytes (proliferative activity) were significantly suppressed in rabbits treated with bendiocarbamate compared with those in control groups and values before the experiment.

Chick development and high dose of bendiocarb

Developmental data of carbamate pesticides are scarce although they generally possess low toxicity for vertebrates. The aim of the study was to investigate the toxicity of bendiocarb to liver and central nervous system of chick embryos. Bendiocarb (1600 μg/egg) was administered to the embryo through membrana papyracea on embryonic day 3 and 10. In the liver and central nervous system we observed no macroscopic or microscopic changes. These organs were also investigated for caspase activity in regard to application of bendiocarb and no differences in the caspase immunopositivity were observed in comparison with the control. The embryolethality after bendiocarb respective dose was high (94 %) on the embryonic day 3, though following results indicated no toxicity to investigated organs and no increase in the number of apoptotic cells in survived chick embryos on both the early (day 3 of incubation) and the later (day 10 of incubation) developmental stage.

Structural alterations in rabbit spleen after bendiocarb administration

The histological structure of rabbit spleen after bendiocarb administration was studied. Bendiocarb was perorally administered for 30 days. At day 10, 20 and 30 morphometric analysis was realized. Quantitative evaluation showed that in the control group the relative spleen volume of white pulp ranged from 35.03 ± 10.94 % and the relative volume of red pulp 64.97 ± 10.94 %. In all experimental groups were detected significantly higher relative volume of red pulp and the lower relative volume of white pulp, except on day 30. The experimental groups showed a significant increase in the number of lymphocytes in comparison with the control group. On day 10 we observed a significant increase in diameter of investigated lymphocytes. The results of our study determined structural alterations in spleen structure after bendiocarb administration, which probably causes alteration in the immune system.

Bendiocarb effect on liver and central nervous system in the chick embryo

The aim of the study was to investigate toxicity of bendiocarb (2, 3-isopropyledene-dioxyphenyl methylcarbamate) to organs of chicken embryo. The toxic action of bendiocarb was observed on liver and central nervous system (CNS). Bendiocarb was administered to chicken embryos at embryonic day (ED) 3 in a dose 500 microg/egg and 10 ED (800 microg/egg). The observations showed no macroscopic or microscopic changes in the liver and CNS with either dose or day of incubation when the bendiocarb was administered. The liver and CNS were also investigated for caspase activity in relation to application of bendiocarb and no differences in the number of cells with caspase immunopositivity were observed in comparison with the control. The results obtained indicate that bendiocarb administered in the respective doses showed no toxicity to investigated organs. Furthermore, both at the early (3 ED) and the later (10 ED) stages of development no increase in numbers of apoptotic cells in chicken embryos was observed.

Encephalitozoonosis in household pet Nederland Dwarf rabbits (Oryctolagus cuniculus)

The paper presents the results of examination of 32 domestically bred rabbits, the breed Nederland Dwarf of Oryctolagus cuniculus, for the presence of Encephalitozoon cuniculi microsporidian species. The results of serological tests for E. cuniculi in 32 rabbits are reviewed along with other follow-up studies of clinical cases. Blood samples were taken from 7 asymptomatic rabbits and 25 rabbits showing neurological and ocular signs suggestive of encephalitozoonosis. In the asymptomatic group, 5 out of 7 rabbits were seropositive (71%). 16 rabbits with clinical diseases showed neurological sings, including torticollis, circus-like movements, loss of weight; 6 of them also showed ataxia, anorexia, asthenia of hind-limbs and 3 showed ocular signs. All 25 rabbits were seropositive. The spores of E. cuniculi were isolated from the faecal samples or kidneys and brain of an animal and subsequently were used for DNA isolation and PCR analysis.