Chitosan/pvp-based mucoadhesive membranes as a promising delivery system of betamethasone-17-valerate for aphthous stomatitis.

Mucoadhesive membranes were proposed in this study as drug delivery system for betamethasone-17-valerate (BMV) in the treatment of recurrent aphthous stomatitis (RAS). The membranes were obtained by using the polymers chitosan (CHI) in both presence and absence of polyvinilpyrrolidone (PVP), following the solvent evaporation method. The presence of PVP in the membranes causes significant modifications in its thermal properties. Changes in the thermal events at 114 and 193 °C (related to BMV melting point), and losses in mass (39.38 and 30.68% for CH:PVP and CH:PVP-B, respectively), suggests the incorporation of BMV in these membranes. However, the morphological aspects of the membranes do not change after adding PVP and BMV. PVP causes changes in swelling ratios (>80%) of the membranes, and it is suggested that the reorganization of the polymer mesh was highlighted by the chemical interactions between the polymers leading to different percentages of BMV released ∼40% and ∼80% from CH-B and CH:PVP-B. BMV release profile follows Korsmeyer and Peppas model (n > 0.89) which suggests that the diffusion of the drug in the swollen matrix is driven by polymer relaxation. In addition, the membranes containing PVP (higher swelling ability) present high rates of tensile strength, and therefore, higher mucoadhesion. Moreover, given the results presented, the developed mucoadhesive membranes are a promising system to deliver BMV for the treatment of RAS.

Griffiths phase and long-range correlations in a biologically motivated visual cortex model.

Activity in the brain propagates as waves of firing neurons, namely avalanches. These waves' size and duration distributions have been experimentally shown to display a stable power-law profile, long-range correlations and 1/f (b) power spectrum in vivo and in vitro. We study an avalanching biologically motivated model of mammals visual cortex and find an extended critical-like region - a Griffiths phase - characterized by divergent susceptibility and zero order parameter. This phase lies close to the expected experimental value of the excitatory postsynaptic potential in the cortex suggesting that critical be-havior may be found in the visual system. Avalanches are not perfectly power-law distributed, but it is possible to collapse the distributions and define a cutoff avalanche size that diverges as the network size is increased inside the critical region. The avalanches present long-range correlations and 1/f (b) power spectrum, matching experiments. The phase transition is analytically determined by a mean-field approximation.

Distribution and temporal prevalence of Theileria orientalis major piroplasm surface protein types in eastern Australian cattle herds.

OBJECTIVE: To determine the distribution of theilerial types in eastern Australian cattle herds and their changing prevalence in regions of New South Wales (NSW). DESIGN: Survey testing of herds in 2010-11 in Queensland (QLD), NSW and Victoria (VIC) where clinical theileriosis was not evident and ongoing surveillance in NSW through laboratory submissions. METHODS: Blood samples were tested by PCR targeting the Theileria orientalis p32 gene and positive tests were examined for the Ikeda, Chitose and Buffeli types. Survey samples from 516 cattle in 50 herds and diagnostic submissions from 434 suspect field cases in 116 herds were analysed. RESULTS: In clinically normal survey cattle, T. orientalis prevalence was high (NSW 23.7%, QLD 56.8%, VIC 34.0%), with variability among regions of each state. Chitose was the most common and widespread type (19.1-43.7% per state), with Buffeli present in all states at a lower prevalence (10.8-24.8% per state). Ikeda was detected in three of five regions in QLD (North, South and South East; prevalence 3.4-15.4%), only one of the surveyed regions in NSW (North Coast; prevalence 74.2%) and in only one animal in VIC. Evidence of clinical disease and laboratory confirmation of Ikeda infection in diagnostic submissions were predominant in several NSW regions, with increasing numbers of affected herds particularly in the coastal Mid-Coast and Cumberland areas. CONCLUSIONS: In those regions where prior evidence of theileriosis was uncommon, Ikeda infection was evident in a limited number of NSW regions and multiple regions in QLD. However, clinical disease has continued to become widespread in NSW and VIC, involving Ikeda strains in many regions.

Evaluation of serovar-independent ELISA antigens of Actinobacillus pleuropneumoniae in pigs following vaccination or experimental challenge with respiratory pathogens and natural A. pleuropneumoniae serovar 1 challenge.

OBJECTIVE: To compare the sensitivity and cross-reactivity of six serological enzyme-linked immunosorbent assays (ELISAs) based on serovar-independent antigens of Actinobacillus pleuropneumoniae (App). DESIGN: An experimental pig trial using direct or natural challenge with App and direct challenge or vaccination using other common respiratory pathogens. PROCEDURE: A 39-kDa outer membrane protein antigen and five recombinant antigens from the ApxIVA gene of App were evaluated. The latter were derived from the ApxIVA N terminus (ApxIVA-N, ApxIVA-NP, ApxIVA-NPS) or C terminus (ApxIVA-C, ApxIVA-CP). Pigs were sampled after direct challenge with App, Pasteurella multocida or Haemophilus parasuis, after vaccination with these organisms and after natural App infection. Clinical and necropsy findings were evaluated. RESULTS: The 39-kDa ELISA had high sensitivity, but cross-reactivity, following P. multocida challenge. ELISAs using ApxIVA N terminus antigens were clearly more sensitive than C terminus antigens for detection of App-induced disease. Although affinity-purified ApxIVA-NP antigen detected marginally more diseased pigs than the -N and -NPS ELISAs, these assays only detected 41-47% of 17 pigs with lung lesions and microbiological evidence of App based on sampling up to 4-5 weeks after natural (13 pigs) or 5 weeks after direct App serovar 1 challenge (4 pigs). CONCLUSIONS: The 39-kDa ELISA readily detects App exposure and infection, but is adversely affected by P. multocida infection. ApxIVA-N-based ELISAs can be used to evaluate the App status of commercial herds, but a proportion of infected and diseased animals are seronegative at 1 month after likely exposure to aerosol transmission of App from clinical cases.

Evaluation of serovar-independent ELISA antigens of Actinobacillus pleuropneumoniae in pigs, following experimental challenge with A. pleuropneumoniae, Mycoplasma hyopneumoniae and Pasteurella multocida.

OBJECTIVE: To compare the sensitivity and specificity of six serological enzyme-linked immunosorbent assays (ELISAs) based on serovar-independent antigens of Actinobacillus pleuropneumoniae (App) and investigate cross-reactivity in disease-free pigs challenged with Mycoplasma hyopneumoniae and Pasteurella multocida. DESIGN: Five experimental pig trials using direct challenge with App serovars 1, 7 or 15 or direct challenge with M. hyopneumoniae and/or various dose rates of P. multocida. PROCEDURE: A 39-kDa outer membrane protein antigen and five recombinant antigens from the apxIVA gene of App were evaluated. The latter were derived from the ApxIVA N-terminus (ApxIVA-N, ApxIVA-NP, ApxIVA-NPS) or C-terminus (ApxIVA-C, ApxIVA-CP). Pigs were sampled after challenge and clinical and necropsy findings evaluated. RESULTS: The 39-kDa ELISA had high sensitivity but lacked specificity, with significantly increased cross-reactivity following P. multocida challenge. ELISAs based on ApxIVA N-terminus antigens were significantly more sensitive than C-terminus antigens for the detection of App-induced disease. Although ApxIVA-N and ApxIVA-NP ELISAs had increased reactivity following P. multocida challenge, they retained high specificity for App-induced disease (90-93%). Affinity purified ApxIVA-NP antigen had marginally better specificity than ApxIVA-N, without reduced sensitivity. Mycoplasma hyopneumoniae did not affect serological cross-reactivity. In disease-free pigs, the specificity of the ApxIVA-NPS ELISA may be adversely affected by nasal carriage of apparently low-virulence App strains. CONCLUSIONS: ApxIVA-N-based ELISAs can be used for evaluating App status in commercial herds, but some appear limited by high carriage rates of low-virulence App. The 39-kDa antigen is only of merit in exclusion of App disease by negative serology.

Comparison of a commercial ELISA with an indirect fluorescent antibody test to detect antibodies to Lawsonia intracellularis in experimentally challenged pigs.

OBJECTIVE: The ability of a new commercial ELISA to detect pigs with subclinical proliferative enteropathy (PE) was compared with the traditional indirect fluorescent antibody test (IFAT). METHODS: Serum samples were selected from pigs with known Lawsonia intracellularis infection status and clinical signs of PE, but the sample population consisted predominantly of pigs subclinically affected by PE. RESULTS: Significant association and agreement were shown between the ELISA and IFAT assays. ELISA results correlated well with the duration of L. intracellularis shedding as detected by polymerase chain reaction. CONCLUSION: ELISA can be successfully used to monitor L. intracellularis infection in pigs.

Bacterial survival studies to assess the efficacy of static pile composting and above ground burial for disposal of bovine carcases.

AIM: To assess the survival of bacteria during two alternative means of cattle carcase disposal in windrows: static pile composting (SPC) and above ground burial in soil (AGB), under temperate climate conditions on agricultural land, compared to surface disposal as the control method. METHODS AND RESULTS: Bacteriological reference materials (pooled bovine faeces in permeable nylon bags and lyophilized cultures of Escherichia coli in glass ampoules) were positioned above and below each of 33 beef cattle carcases (250-300 kg). Temperatures at these sites were monitored with data loggers, while temperature and CO(2) probes were applied repeatedly at varying depths along the windrows. Aliquots of each reference material were cultured from three randomly selected animals from the SPC and AGB group and from all three control animals on five occasions (at 28, 56, 84, 126 and 182 days). SPC was highly efficacious in the destruction of coliforms in faeces and E. coli in ampoules within 28 days, while AGB was not significantly better than controls until 84 days, and bacteria in reference materials above the AGB carcases were still viable after 182 days. Temperature probes and loggers showed SPC provided sustained temperatures of 55-70°C, while AGB did not reach temperatures of 30°C, and the temperature differences correlated with bacteriological findings. CONCLUSIONS: In relation to emergency disease management, SPC can be successfully applied to eliminate pathogenic bacteria in cattle carcases, but AGB is unsuitable for carcase disposal. SIGNIFICANCE AND IMPACT OF THE STUDY: In emergency, animal disease outbreaks in temperate climates requiring large-scale ruminant carcase disposal, SPC can be successfully applied for the destruction of micro-organisms.

Prevalence of antibodies to Lawsonia intracellularis in pig herds in Australia.

OBJECTIVE: Proliferative enteropathy (PE) of pigs is caused by Lawsonia intracellularis. Clinical severity appears to depend, at least partly, on the infective dose and strain of L. intracellularis. Serological tests are able to detect subclinical disease. The Bioscreen ELISA for detecting L. intracellularis-specific antibodies is widely used to monitor the circulating antibody status of pigs in Australia, but its sensitivity and specificity have not been reported. The aim of the present study was to measure the seroprevalence of antibodies to L. intracellularis in growing pigs in Australia. METHODS: Test sera were sourced from 1817 serum samples collected from finisher pigs from 63 herds across Australia in 2001, selected from a larger sample of 180 herds to represent the contribution that each herd size makes to the number of pigs produced. The test sera were the most recent collection of pig sera from all states and samples had been stored at -80 degrees C from 2001 until testing was conducted in 2008. Sera were tested using the BioScreen ELISA. RESULTS: All herds tested positive for L. intracellularis-specific antibodies. The mean percentage of positive samples within each herd was 84.2% (range 31.3-100%). CONCLUSIONS: Lawsonia intracellularis is endemic in pig herds in Australia and cost-effective strategies to reduce reliance on antibiotics, such as vaccination and/or all-in/all-out pig flow coupled with cleaning and disinfection of pens, are warranted.

Serological responses to two serovar-independent ELISA antigens of Actinobacillus pleuropneumoniae in Australian commercial pig herds.

OBJECTIVE: To compare serological responses in pig herds classified as low or high risk for disease caused by Actinobacillus pleuropneumoniae, using two ELISA tests based on serovar-independent antigens. PROCEDURE: Cross-sectional sampling was undertaken in 13 commercial herds, the clinical and slaughter histories of which indicated either freedom from (n = 5) or prior confirmed cases of A. pleuropneumoniae (n = 8). In nine herds, approximately 40 pigs each were sampled at 4, 8, 12, 16 and 20 weeks. Three of the remaining four herds were sampled between 6 and 30 weeks of age, and the last was sampled only prior to slaughter, at approximately 24 weeks. Sera were tested in ELISA based on two antigens common among A. pleuropneumoniae serovars: a 39-kDa outer membrane protein and a recombinant ApxIVA-N terminus protein. RESULTS: Sampling of 1 and 5 to 6-month-old pigs provided the most useful information on herd status. The 39-kDa ELISA was sensitive in detecting infected herds, but had evidence of cross-reactivity with high seroreactivity rates in older pigs in some low-risk herds. The ApxIVA-N ELISA was less seroreactive in high-risk herds and had higher specificity in low-risk herds. CONCLUSION: ELISA based on the 39-kDa subunit are of limited use, because of possible cross-reactivity, but a high negative predictive value may be useful for risk assessment in suspect herds. Maternal antibody to ApxIVA-N may be of value in detecting high-risk herds, but 5% of 4-week-old pigs in low-risk herds were also seropositive in this assay.

Chocolate procyanidins decrease the leukotriene-prostacyclin ratio in humans and human aortic endothelial cells.

BACKGROUND: Polyphenolic phytochemicals inhibit vascular and inflammatory processes that contribute to disease. These effects are hypothesized to result from polyphenol-mediated alterations in cellular eicosanoid synthesis. OBJECTIVE: The objective was to determine and compare the ability of cocoa procyanidins to alter eicosanoid synthesis in human subjects and cultured human aortic endothelial cells. DESIGN: After an overnight fast, 10 healthy subjects (4 men and 6 women) consumed 37 g low-procyanidin (0.09 mg/g) and high-procyanidin (4.0 mg/g) chocolate; the treatments were separated by 1 wk. The investigation had a randomized, blinded, crossover design. Plasma samples were collected before treatment and 2 and 6 h after treatment. Eicosanoids were quantitated by enzyme immunoassay. Endothelial cells were treated in vitro with procyanidins to determine whether the effects of procyanidin in vivo were associated with procyanidin-induced alterations in endothelial cell eicosanoid synthesis. RESULTS: Relative to the effects of the low-procyanidin chocolate, high-procyanidin chocolate induced increases in plasma prostacyclin (32%; P<0.05) and decreases in plasma leukotrienes (29%; P<0.04). After the in vitro procyanidin treatments, aortic endothelial cells synthesized twice as much 6-keto-prostaglandin F(1alpha) (P<0.01) and 16% less leukotriene (P<0.05) as did control cells. The in vitro and in vivo effects of procyanidins on plasma leukotriene-prostacyclin ratios in culture medium were also comparable: decreases of 58% and 52%, respectively. CONCLUSION: Data from this short-term investigation support the concept that certain food-derived flavonoids can favorably alter eicosanoid synthesis in humans, providing a plausible hypothesis for a mechanism by which they can decrease platelet activation in humans.

Kinesin participates in melanosomal movement along melanocyte dendrites.

Movement of melanosomes along melanocyte dendrites is necessary for the transfer of melanin pigment from melanocytes to basal and suprabasal keratinocytes, an event critical to epidermal photoprotection and maintenance of normal skin color. Recent murine data suggest that in melanocyte dendrites the microtubule-associated melanosome movement is bidirectional and that actin-associated myosin V secures the peripheral melanosomes, preparing them to be transferred to surrounding keratinocytes. We now report that human melanocytes express high levels of kinesin, a molecule that participates in microtubule-associated transport of organelles in other cell types, and that ultrastructurally kinesin molecules are closely associated with melanosomes. To determine whether kinesin participates in melanosomal transport, cultured melanocytes were treated with sense or antisense oligonucleotides complementary to kinesin heavy chain sequences. Antisense oligonucleotides decreased kinesin protein levels and inhibited the bidirectional movement of the melanosomes, promoting their backward movement. Furthermore, guinea pigs were exposed to ultraviolet B irradiation, known to enhance transport of melanosomes from melanocytes to epidermal keratinocytes, and then were treated with kinesin sense or antisense oligonucleotides. The areas that were treated with kinesin antisense oligonucleotides showed significantly less pigmentation clinically and histologically than control (sense) oligonucleotide-treated areas. As observed ultrastructurally, in antisense-treated areas melanosomes remained in melanocyte dendrites but over several days were not transferred to the surrounding keratinocytes. Our study supports a major role for kinesin in microtubule-associated anterograde melanosomal transport in human melanocyte dendrites.

Mastitis, polyarthritis and abortion caused by Mycoplasma species bovine group 7 in dairy cattle.

OBJECTIVE: To report an outbreak of mastitis, polyarthritis and abortion caused by Mycoplasma sp bovine group 7 in three large, centrally-managed dairies and to review the relevant literature. DESIGN: Epidemiological, clinical and laboratory data were analysed, collated and reported. Multidisciplinary procedures were employed. These included clinical assessment and comprehensive laboratory investigations of affected calves, aborted foetuses and milk samples. Mycoplasma cultures and genetic analyses of isolates were undertaken to identify the aetiological agent. RESULTS: About 30% of 240 calves usually kept in a calf rearing facility developed severe polyarthritis as a result of Mycoplasma sp bovine group 7 infection between 2 and 3 weeks of age. Multiple abortions occurred on these farms. Mycoplasma sp bovine group 7 was recovered from the fibrinopurulent synovial exudates of four 14-day-old calves, from the stomach contents and lungs of two aborted foetuses, from 14 of 21 bulk milk and four of 10 mastitic quarters. Three bulk colostrum samples cultured during the outbreak were negative for mycoplasma. CONCLUSION: Mycoplasma sp bovine group 7 caused significant economic losses as a result of polyarthritis, abortion and mastitis. The disease probably originated from udder infections with spread being facilitated by the decreased use of tetracycline in the treatment of mastitis. Neonatal calves were most likely infected by the consumption of milk contaminated with the organism. Abortions presumably resulted from mycoplasmaemia. This appears to be the first report in Australia of bovine abortion resulting from Mycoplasma sp infection.