Pharmacokinetic/pharmacodynamic integration and modelling of amoxicillin for the calf pathogens Mannheimia haemolytica and Pasteurella multocida.

The antimicrobial properties of amoxicillin were determined for the bovine respiratory tract pathogens, Mannheima haemolytica and Pasteurella multocida. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill curves were established. Pharmacokinetic (PK)/pharmacodynamic (PD) modelling of the time-kill data, based on the sigmoidal Emax equation, generated parameters for three levels of efficacy, namely bacteriostatic, bactericidal (3log10 reduction) and 4log10 reduction in bacterial counts. For these levels, mean AUC(0-24 h) /MIC serum values for M. haemolytica were 29.1, 57.3 and 71.5 h, respectively, and corresponding values for P. multocida were 28.1, 44.9 and 59.5 h. Amoxicillin PK was determined in calf serum, inflamed (exudate) and noninflamed (transudate) tissue cage fluids, after intramuscular administration of a depot formulation at a dosage of 15 mg/kg. Mean residence times were 16.5 (serum), 29.6 (exudate) and 29.0 h (transudate). Based on serum MICs, integration of in vivo PK and in vitro PD data established maximum concentration (Cmax )/MIC ratios of 13.9:1 and 25.2:1, area under concentration-time curve (AUC0-∞ )/MIC ratios of 179 and 325 h and T>MIC of 40.3 and 57.6 h for P. multocida and M. haemolytica, respectively. Monte Carlo simulations for a 90% target attainment rate predicted single dose to achieve bacteriostatic and bactericidal actions over 48 h of 17.7 and 28.3 mg/kg (M. haemolytica) and 17.7 and 34.9 mg/kg (P. multocida).

Insulin but not leptin protects olfactory mucosa from apoptosis.

The mammalian olfactory mucosa (OM) is continually renewed throughout life. Owing to their position in the nasal cavity, OM cells are exposed to multiple insults, including high levels of odourants that can induce their death. OM regeneration is therefore essential to maintain olfactory function, and requires the tight control of both cell death and proliferation. Apoptosis has been implicated in OM cell death. Olfaction is one of the senses involved in food intake and depends on individual nutritional status. We have previously reported the influence of hormones related to nutritional status on odour perception and have shown that the OM is a target of insulin and leptin, two hormones known for their anti-apoptotic properties. In the present study, we investigated the potential anti-apoptotic effect of these metabolic hormones on OM cells. Both Odora cells (an olfactive cell line) and OM cells treated with etoposide, a p53 activity inducer, exhibited mitochondrial-dependent apoptosis that was inhibited by the pan-caspase inhibitor zVAD-fmk. Insulin, but not leptin, impaired this apoptotic effect. Insulin addition to the culture medium reduced p53 phosphorylation, caspase-3 and caspase-9 cleavage, and caspase-3 enzymatic activity induced by etoposide. The apoptotic wave observed in the OM after interruption of the neuronal connections between the OM and the olfactory bulb by bulbectomy was impaired by intranasal insulin treatment. These findings suggest that insulin may be involved in OM cellular dynamics, through endocrine and/or paracrine-autocrine effects of circulating or local insulin, respectively.

Paw inflammation model in dogs for preclinical pharmacokinetic/pharmacodynamic investigations of nonsteroidal anti-inflammatory drugs.

The goal of the present study was to develop and validate a new canine model of inflammation. The motivation was to make available a scientifically appropriate and ethically acceptable model to conduct pharmacokinetic/pharmacodynamic investigations for testing nonsteroidal anti-inflammatory drugs in dogs. A kaolin-induce paw inflammation model previously developed in cats was adapted to the dog. The paw inflammation developed within a few hours, reached maximum values 24 h and up to 3 days after kaolin administration, and then progressively resolved over 2 months. Five end points of clinical interest (body temperature, creeping time under a tunnel, paw withdrawal latency to a standardized thermal stimulus, lameness score, and vertical force developed during walking on a force plate) were measured regularly over the next 24 h and beyond to characterize the time development of the inflammation either in control conditions (placebo period) or after the administration of meloxicam (test period) according to a crossover design. Pharmacodynamic data were modeled using an indirect response pharmacokinetic/pharmacodynamic model. This model described three effects of meloxicam, namely, classic anti-inflammatory, analgesic, and antipyretic effects. The mean plasma meloxicam IC(50) values were 210 ng/ml for the antipyretic effect, 390 ng/ml for the analgesic effect, and 546 ng/ml for the vertical force exerted by the paw on the ground as measured by force plates. These in vivo IC(50) values require approximately 80 (antipyretic effect) to 90% (all other effects) cyclooxygenase-2 inhibition as calculated ex vivo whole-blood assay data.

Analyzing cranberry bioactive compounds.

There is a growing public interest for the North American cranberry (Vaccinium macrocarpon) as a functional food because of the potential health benefits linked to phytochemical compounds present in the fruit--the anthocyanin pigments, responsible for its brilliant red color, and other secondary plant metabolites (flavonols, flavan-3-ols, proanthocyanidins, and phenolic acid derivatives). Isolation of these phenolic compounds and flavonoids from a sample matrix is a prerequisite to any comprehensive analysis scheme. By far the most widely employed analytical technique for the characterization of these compounds has been high-performance liquid chromatography(HPLC) coupled with ultraviolet-visible(UV/Vis) and mass spectrometer(MS) detection. This review covers the cranberry major bioactive compounds, the extraction and purification methods, and the analytical conditions for HPLC used to characterize them. Extraction, chromatographic separation and detection strategies, analyte determinations, and applications in HPLC are discussed and the information regarding methods of specific cranberry analyte analyses has been summarized in tabular form to provide a means of rapid access to information pertinent to the reader.

Bioactive compounds in cranberries and their biological properties.

Cranberries are healthy fruit that contribute color, flavor, nutritional value, and functionality. They are one of only three fruits native to America. Over the past decade, public interest for the North American cranberry (Vaccinium macrocarpon) has been rising with reports of their potential health benefits linked to the numerous phytochemicals present in the fruit--the anthocyanins, the flavonols, the flavan-3-ols, the proanthocyanidins, and the phenolic acid derivatives. The presence of these phytochemicals appears to be responsible for the cranberry property of preventing many diseases and infections, including cardiovascular diseases, various cancers, and infections involving the urinary tract, dental health, and Helicobacter pylori-induced stomach ulcers and cancers. Recent years have seen important breakthroughs in our understanding of the mechanisms through which these compounds exert their beneficial biological effects, yet these remain to be scientifically substantiated. In this paper these characteristics, as well as the antioxidant, radical scavenging, antibacterial, antimutagen, and anticarcinogen properties of cranberry major bioactive compounds are explained.

Antimicrobial potential of immobilized Lactococcus lactis subsp. lactis ATCC 11454 against selected bacteria.

Immobilization of living cells of lactic acid bacteria could be an alternative or complementary method of immobilizing organic acids and bacteriocins and inhibit undesirable bacteria in foods. This study evaluated the inhibition potential of immobilized Lactococcus lactis subsp. lactis ATCC 11454 on selected bacteria by a modified method of the agar spot test. L. lactis was immobilized in calcium alginate (1 to 2%)-whey protein concentrate (0 and 1%) beads. The antimicrobial potential of immobilized L. lactis was evaluated in microbiological media against pathogenic bacteria (Escherichia coli, Salmonella, and Staphylococcus aureus) or Pseudomonas putida, a natural meat contaminant, and against seven gram-positive bacteria used as indicator strains. Results obtained in this study indicated that immobilized L. lactis inhibited the growth of S. aureus, Enterococcus faecalis, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus sakei, Kocuria varians, and Pediococcus acidilactici. Only 4 h of incubation at 35 degrees C resulted in a clear inhibition zone around the beads that increased with time. With the addition of 10 mM of a chelating agent (EDTA) to the media, results showed growth inhibition of E. coli; however, P. putida and Salmonella Typhi were unaffected by this treatment. These results indicate that immobilized lactic acid bacteria strains can be successfully used to produce nisin and inhibit bacterial growth in semisolid synthetic media.

Microbial and sensory quality of marinated and irradiated chicken.

Chicken legs were subjected to two pretreatments (packaged in air or marinated in natural plant extracts and then packaged in air) followed by irradiation (0, 3, or 5 kGy). The control and irradiated chicken legs were stored at 4 degrees C and underwent microbial analysis (mesophilic aerobic plate counts and Salmonella detection) and sensory evaluation at predetermined intervals. Microbial analysis indicated that irradiation had a significant effect (P < or = 0.05) on the mesophilic aerobic plate counts of the poultry. For each treatment, the bacterial growth decreased with an increase of irradiation dose. The marinade had an additive effect with irradiation in reducing bacterial growth and controlling proliferation during storage at 4 +/- 1 degree C. No Salmonella was observed until day 12 in marinated chicken irradiated at 3 kGy and for all experiments with chicken legs stored under air or marinated at 5 kGy. However, Salmonella was found in chicken legs irradiated at 3 kGy in air and in nonirradiated samples. The sensory evaluation indicated a significant (P < or = 0.05) difference in odor and flavor intensities between the irradiated chicken at 5 kGy and the control. No significant difference was found (P > 0.05) between the marinated chicken irradiated at 5 kGy and the control.

Physicochemical properties and bacterial resistance of biodegradable milk protein films containing agar and pectin.

Free-standing sterilized edible films based on milk proteins, namely calcium caseinate and whey protein isolate, and polysaccharides, namely pectin and agar, were developed. Cross-linking of the proteins was achieved by the combination of thermal and radiative treatments. Autoclaving pectin and agar prior to their addition to the protein solutions generated films with an improved (P < or = 0.05) puncture strength. The presence of proteins and pectin-agar in the film formulation enhanced (P < or = 0.05) the moisture barrier of the films by 18%. A strain of Streptococcus thermophilus was used to assess the biodegradability behavior of the cross-linked films. Microbiological counts and soluble nitrogen analysis confirmed the biodegradability property of the milk protein films containing autoclaved pectin and agar.

Isothermal calorimetry study of calcium caseinate and whey protein isolate edible films cross-linked by heating and gamma-irradiation.

The contribution of thermal and radiative treatments as well as the presence of some excipients, namely glycerol, carboxymethylcellulose (CMC), pectin, and agar, on the formation of protein-protein interactions as well as the formation and loss of protein-water interactions was investigated by means of differential scanning calorimetry in an isothermal mode. Protein-water interactions were assessed through measurement of the heat of the wetting parameter. Isothermal calorimetry measurements pointed out that gamma-irradiation does not favor protein-water interactions, as reflected by its endothermic contribution (P < or = 0.05) to the heat of wetting values. Although significant (P < or = 0.05), the effect of the thermal treatment on endothermic responses using isothermal calorimetry was found to be somewhat lower. Among excipients added to biofilm formulations, glycerol generated the most important losses of protein-water interactions, as inferred by its significant (P < or = 0.05) endothermic impact on the heat of wetting values.

Cellular hyperimmunoreactivity to rubella virus synthetic peptides in chronic rubella associated arthritis.

OBJECTIVES: Immune recognition of the major structural proteins of rubella virus by peripheral blood mononuclear cells and synovial inflammatory infiltrates of a patient with documented chronic rubella associated arthritis was compared with responses of normal healthy rubella virus immunoreactive subjects to establish if there were unusual response patterns associated with rubella associated arthritis in this subject. METHODS: Synthetic peptides (16-33 amino acids in length) representing selected amino acid sequences of the rubella virus envelope (E1 and E2) and capsid (C) proteins were used in lymphocyte stimulation assays with peripheral blood mononuclear cells or synovial inflammatory infiltrates to determine T lymphocyte recognition of antigenic sites within the synthetic peptides. A rubella virus specific polymerase chain reaction was used to determine the persistence of rubella virus in the patient's cells. RESULTS: The patient's peripheral blood mononuclear cells showed abnormally increased lymphoproliferative responses to three E1 synthetic peptides encompassing residues 219-234, 389-411, and 462-481, and one E2 synthetic peptide containing the sequence 50-72, of which the last three were predicted to contain T cell antigenic sites. Although the patient's peripheral blood mononuclear cells showed positive proliferative responses to C synthetic peptides, these were not unusual. The number of synthetic peptides within the E1, E2, and C panels recognised by the patient's peripheral blood mononuclear cells was greater than was previously observed in normal healthy subjects. The recognition of synthetic peptides by synovial inflammatory infiltrates was similar to peripheral blood mononuclear cells but the responses measured were lower. The polymerase chain reaction was negative for rubella virus detection in peripheral blood mononuclear cells and synovial inflammatory infiltrates. CONCLUSIONS: Abnormally increased T cell recognition of antigenic sites within rubella virus E1 and E2 proteins observed in this patient with rubella associated arthritis suggests chronic antigenaemia due to persistent rubella virus in tissue sites other than peripheral blood mononuclear cells or synovial inflammatory infiltrates.

Adjuvanticity of stearyl tyrosine on the antibody response to peptide 503-535 from HIV gp160.

In this present report we compare the humoral immune response induced by immunization with an HIV-1 gp160 peptide corresponding to amino acid sequence 503-535 complexed with different adjuvants. Specifically, the antipeptide, anti-HIV-1 gp160 and neutralizing antibody responses were measured in groups of mice and baboons that received peptide 503-535 conjugated to a carrier protein in either saline, alum, or stearyl tyrosine. The highest antibody responses were induced when mice and baboons were immunized with peptide adsorbed on stearyl tyrosine. These data indicate that stearyl tyrosine represents a potent candidate as a nontoxic adjuvant not only for subunit viral vaccines, but also for HIV peptides.