Gantrez AN nanoparticles for ocular delivery of memantine: in vitro release evaluation in albino rabbits.

AIM: To prepare and evaluate the in vitro release of memantine-loaded poly(anhydride) (Gantrez®) nanoparticles (NPs). The clinical safety and retinal toxicity caused by unloaded NPs after sub-Tenon and intravitreal ocular injections were also evaluated. METHODS: Preparation and characterization of this type of NP as well as the in vitro release study are described. Twenty-three healthy New Zealand rabbits were used for clinical and histological assessment after sub-Tenon and intravitreal ocular injections of unloaded NPs. RESULTS: The amount of drug associated with NPs was 55 µg of memantine/mg of NP. The release profile of memantine from this type of NPs was characterized by an initial burst effect, followed by continuous release of the drug for at least 15 days. No relevant complications were found during the clinical follow-up. The histological evaluation suggested that Gantrez NPs are well tolerated after sub-Tenon ocular injection and that signs of inflammation during the first days after intravitreal ocular injections can be considered a normal reaction of the eye's defence mechanism.

Preclinical activity of LBH589 alone or in combination with chemotherapy in a xenogeneic mouse model of human acute lymphoblastic leukemia.

Histone deacetylases (HDACs) have been identified as therapeutic targets due to their regulatory function in chromatin structure and organization. Here, we analyzed the therapeutic effect of LBH589, a class I-II HDAC inhibitor, in acute lymphoblastic leukemia (ALL). In vitro, LBH589 induced dose-dependent antiproliferative and apoptotic effects, which were associated with increased H3 and H4 histone acetylation. Intravenous administration of LBH589 in immunodeficient BALB/c-RAG2(-/-)γc(-/-) mice in which human-derived T and B-ALL cell lines were injected induced a significant reduction in tumor growth. Using primary ALL cells, a xenograft model of human leukemia in BALB/c-RAG2(-/-)γc(-/-) mice was established, allowing continuous passages of transplanted cells to several mouse generations. Treatment of mice engrafted with T or B-ALL cells with LBH589 induced an in vivo increase in the acetylation of H3 and H4, which was accompanied with prolonged survival of LBH589-treated mice in comparison with those receiving vincristine and dexamethasone. Notably, the therapeutic efficacy of LBH589 was significantly enhanced in combination with vincristine and dexamethasone. Our results show the therapeutic activity of LBH589 in combination with standard chemotherapy in pre-clinical models of ALL and suggest that this combination may be of clinical value in the treatment of patients with ALL.

The distribution of immune cells in the lungs of classical and atypical ovine pulmonary adenocarcinoma.

Ovine pulmonary adenocarcinoma (OPA) is a contagious tumour caused by infection of sheep with Jaagsiekte sheep retrovirus. Two forms of OPA have been identified, classical and atypical, which can be distinguished clinically and pathologically. Most notably classical OPA is progressive until death, while atypical OPA remains subclinical. In the present study the local immune responses in the lungs of cases of atypical OPA were compared with those from classical cases by immunohistochemistry using a panel of mouse anti-sheep mAbs. Distinct differences in the distribution of immune cell subsets in the two forms of OPA were observed. In particular there was an intratumoural influx of T cell subsets and MHC Class II expression on the tumour cells in atypical OPA, neither of which was seen in classical OPA. It is possible that these differences may contribute, at least in part, to determining the progressive course of classical OPA compared with the subclinical nature of atypical OPA.

A case of ovine female XY sex reversal syndrome not related to anomalies in the sex-determining region Y (SRY).

The human XY gonadal sex reversal is a rare disease. Primary amenorrhea, lack of secondary sexual characteristics and the possible existence of streak gonads are the most common signs of this syndrome. Five cases of this syndrome have been described in the last 42 years in bovines. However, to the knowledge of the authors, no similar descriptions are available in sheep. In the present report, we are presenting the case of a 4 year old ewe 2n = 54,XY showing primary sterility and total absence of masculinization signs. The promoter and the complete coding segment of the sex determining region Y (SRY) were sequenced and found to be absolutely normal. The presence of the testis-specific protein gene (TSPY) was also verified by means of PCR. Necropsy findings include short vagina, lack of uterus and complete absence of masculine remains. Streak gonads concordant with previous descriptions in humans were also found.

18F-FDG metabolism in a rat model of chronic infarction: a 17-sector semiquantitative analysis.

UNLABELLED: Strategies to establish the functional benefit of cell therapy in cardiac regeneration and the potential mechanism are needed. AIMS: Development of a semi-quantitative method for non invasive assessment of cardiac viability and function in a rat model of myocardial infarction (MI) based on the use of microPET. ANIMALS, METHODS: Ten rats were subjected to myocardial imaging 2, 7, 14, 30, 60 and 90 days after left coronary artery ligation. Intravenous 18F-fluoro-2-deoxy-2-D-glucose (18F-FDG) was administered and regional 18F activity concentrations per unit area were measured in 17 regions of interest (ROIs) drawn on cardiac polar maps. By comparing the differences in 18F uptake between baseline and each of the follow up time points, parametric polar maps of statistical significance (PPMSS) were calculated. Left ventricular ejection fraction (LVEF) was blindly assessed echocardiographically. All animals were sacrificed for histopathological analysis after 90 days. RESULTS: The diagnostic quality of 18F-FDG microPET images was excellent. PPMSS demonstrated a statistically significant decrease in 18F concentrations as early as 48 hours after MI in 4 of the 17 ROIs (segments 7, 13, 16 and 17; p < 0.05) that persisted throughout the study. Semiquantitative analysis of 18F-FDG uptake correlated with echocardiographic decrease in LVEF (p < 0.001). CONCLUSION: The use of PPMSS based on 18F-FDG-microPET provides valuable semi-quantitative information of heart glucose metabolism allowing for non-invasive follow up thus representing a useful strategy for assessment of novel therapies in cardiac regeneration.

Biochemical changes in apparently normal sheep from flocks affected by polioencephalomalacia.

Blood samples were obtained for determination of the activities of lactate, pyruvate and erythrocyte transketolase, and faeces as samples for estimation of thiaminase, from 190 apparently healthy sheep from 19 flocks in which at least one animal had been diagnosed with polioencephalomalacia (PEM), from 59 control animals and from 7 affected by PEM. Feed and pasture grass samples were collected for thiaminase analysis and thiaminase was assayed in ryegrass and fescue. Decreased erythrocyte transketolase activity, accompanied by a corresponding rise in the thiamin pyrophosphate effect, and estimation of the thiaminase content in faeces, may be useful diagnostic procedures by which to identify periods of greater risk, during which animals could develop PEM. The changes in the diet probably acted as a primary factor for microbial production of thiaminases in replacement ewes. In these, the prevalence was higher in the spring months.

Experimental transmission of enzootic intranasal tumors of goats.

The successful experimental transmission of enzootic intranasal tumor (EIT) from goat to goat is described. Ten kids, less than 48 hours old, from a flock free of the disease and seronegative for ruminant lentiviruses were inoculated intranasally or intrasinusally with either nasal fluid from goats with naturally occurring EIT or EIT retrovirus concentrated from such fluids. EIT was induced in three kids after 12-24 months. The EIT retrovirus was demonstrated in tumor material from each of the three kids by western blotting and electron microscopy. All kids were seronegative for ruminant lentiviruses.

Expression of glial fibrillary acidic protein and glutamine synthetase genes in the natural scrapie of sheep.

Gene expression of two astroglial markers, glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), was investigated in cerebellum and brainstem from scrapie-affected sheep. The GFAP and GFAP-mRNA concentrations were increased in the two cerebral regions studied in the scrapie-affected animals as compared to the controls. The good correlation between the increase in GFAP and GFAP-mRNA concentrations found in scrapie-affected sheep indicates a significant de novo synthesis of GFAP in this pathology. In contrast to these results, in scrapie no significant differences in GS-mRNA content appeared in either brain area from scrapie-affected sheep as compared to the controls. This fact could suggest some specificity of GFAP expression changes in this pathology. The overexpression of GFAP gene could be related to a possible interaction between GFAP and scrapie infectious agent in astrocytes. The relative increase in the GFAP and its encoding message in affected animals was higher in the cerebellum than in the brainstem, which would suggest regional comparative differences in the effect here described.

Pathology of enzootic intranasal tumor in thirty-eight goats.

Intranasal tumors were studied in 38 goats ranging from 7 months to 8 years of age of both Murciana-Granadina and crossed breeds. Tumors were diagnosed in eight herds. Clinically, the affected goats showed a copious seromucous nasal discharge, ocular protrusion, and skull deformations. The tumors originated from the ethmoid region. They involved one or both nasal cavities, although most were bilateral (26/38). The tumors were generally accompanied by inflammatory polyps. The histologic patterns were very similar in all cases, and the tumors were classified as low grade adenocarcinomas of the nasal glands. Histochemical, immunohistochemical, and ultrastructural studies suggested that the serous glands of nasal mucosa were the probable origin of the neoplastic cells. Budding and extracellular retrovirus-like particles were observed ultrastructurally in 6/8 tumors. The similarities between these caprine tumors and nasal tumors in sheep and the etiologic role of the retrovirus are discussed.

Enzootic nasal tumour of goats: demonstration of a type D-related retrovirus in nasal fluids and tumours.

Nasal exudate and tumour tissue from goats with enzootic nasal tumours were shown to contain a reverse transcriptase activity associated with a particle of buoyant density typical of retroviruses. The same particle contained a 25,000 Mr protein that cross-reacted with the p27 of Mason-Pfizer monkey virus (MPMV) and with p25 of sheep pulmonary adenomatosis retrovirus. It also contained a low Mr protein related to p10-12 of MPMV.

Infection of rabbit mammary glands with ovine mastitis bacterial strains.

An experimental model was developed in rabbits to study ovine mastitis. A total of 19 ovine mastitis bacterial strains (seven Staphylococcus aureus, four Staph. chromogenes, four Staph. hyicus and four Escherichia coli) were used for mammary gland infections. The histopathological results showed that the ovine mastitis types corresponded to experimental infections produced in the rabbit with the ovine strains. These results helped the grading of the bacterial species tested according to the severity of their effects on the mammary gland. The most pathogenic species was Staph. aureus, followed by E. coli, Staph. hyicus and Staph. chromogenes, in that order. There was, however, variation among strains within a given species (e.g. one out of seven Staph. aureus strains gave rise to a mild infection in sheep and rabbits). The procedure was simple and consisted of introducing bacterial suspensions through alternate teat ducts of does with the help of a cannula. It helped minimize the number of animals required in the experiments.