Determination of cloxacillin residues in dairy cows after intramammary administration

The aim of this study was to perform a comparative analysis of the characteristics of cloxacillin (CLO) (MRL of withdrawal in bovine milk is 30 ng/g) after a single intramammary (IMM) dose in the dry period (DP) and lactation (LP), and to establish a high‐performance liquid chromatography (HPLC) analytical method for CLO detection in milk. The research was conducted on a group of 10 cows in DP and 10 in LP. A single dose of 600 mg of CLO was administrated by the IMM route for a single quarter in DP and 500 mg for a single quarter in LP. CLO concentration was analyzed by HPLC. CLO was monitored at a wavelength of 206 nm. Pharmacokinetic calculations were performed using Phoenix^® WinNonlin^® 6.4 software. The calibration curve was linear over the range of 13.03–28 019.00 ng/g with the coefficient of determination R² > 0.999. CLO withdrawal in both the LP and DP group had a biphasic nature. The total CLO elimination in the DP and LP group was reached after 36 and 6.5 days, respectively. A quantitative and confirmatory method for the determination of CLO in fresh milk has been established. We have confirmed that the withdrawal of CLO in the DP group is not a linear process and has a stepwise character.     

Nasal immunization with inhibin DNA vaccine delivered by attenuated Salmonella choleraesuis for improving ovarian responses and fertility in cross‐bred buffaloes

This study was conducted to determine the effect of immunization with inhibin DNA vaccine delivered by attenuated Salmonella choleraesuis on ovarian responses and fertility in cross‐bred buffaloes. A total of 134 cross‐bred buffaloes were divided into four groups: groups T1 (n = 34), T2 (n = 35) and T3 (n = 31) were nasal immunized twice a day with 10 ml of 1 × 10¹⁰ CFU/ml of the C501 (pVAX‐asd‐IS) vaccine for 5, 3 and 1 day, respectively. Group C (n = 34) was nasal immunized with 10 ml PBS for 5 days. All animals were immunized twice with an interval of 14 days and administered with 200 μg of a GnRH analogue on day 28, 0.5 mg PGF_2α on day 35 and 200 μg of the same GnRH analogue on day 37. TAI was performed at 18 and 24 hr after the second GnRH treatment. Fourteen days after primary immunization, C501 (pVAX‐asd‐IS) elicited significant immune responses, and anti‐inhibin IgG antibody titres in group T1 were significantly higher (p < .01) than groups T3 and C. After the second GnRH treatment, the growth speed of the dominant follicles in group T1 was significantly faster (p < .05) than groups T3 and C. The number and diameter of large follicles (≥10 mm) as well as ovulatory follicles in group T1 were the greatest in all groups, resulting in a greater conception rate in buffaloes with positive anti‐inhibin antibodies. These results demonstrate that immunization with the C501 (pVAX‐asd‐IS) vaccine, coupled with the Ovsynch protocol, could be used as an alternative approach to improve reproductive performance in cross‐bred buffaloes.     

Pharmacokinetics of tramadol and metabolites after injective administrations in dogs

The aim of this study was to determine the pharmacokinetics of tramadol and its main metabolites after i.v. and i.m. injections. The pharmacokinetic cross-over study was carried out on 6 healthy male beagle dogs. Tramadol was administered by intravenous (i.v.) and intramuscular (i.m.) injection at 4 mg/kg. Tramadol and its main metabolites O-desmethyl-tramadol (M1), N-,N-didesmethyl-tramadol (M2) and N-,O-didesmethyl-tramadol (M5) concentrations were measured in plasma samples by a HPLC coupled with fluorimetric detection; pharmacokinetic evaluations were carried out with a compartmental and non-compartmental model for tramadol and its metabolites, respectively. The bioavailability of the drug, ranging between 84-102% (mean 92%), was within the generally accepted values for a positive bioequivalence decision of (80-125%). After the i.m. injection the mean plasma drug concentration peak was reached after a T(max) of 0.34 h with a C(max) of 2.52 microg/mL. No therapeutic relevant differences were observed between i.m. and i.v. administration. The minimal effective plasma concentration was reached after a few minutes and maintained for about 6-7 h in both administrations. M1 plasma concentration was low and the amounts of the other metabolites produced were analogous in both routes of administration. In conclusion, tramadol was rapidly and almost completely absorbed after i.m. administration and its systemic availability was equivalent to the i.v. injection. The different onset time and duration of action observed were very small and probably therapeutically irrelevant. The i.m. injection is a useful alternative to i.v. injection in the dog.     

Bragg diffraction from crystallized ion plasmas

Single crystals of a one-component plasma were observed by optical Bragg diffraction. The plasmas contained 10(5) to 10(6) single-positive beryllium-9 ions (9Be+) at particle densities of 10(8) to 10(9) per cubic centimeter. In approximately spherical plasmas, single body-centered cubic (bcc) crystals or, in some cases, two or more bcc crystals having fixed orientations with respect to each other were observed. In some oblate plasmas, a mixture of bcc and face-centered cubic ordering was seen. Knowledge of the properties of one-component plasma crystals is required for models of white dwarfs and neutron stars, which are believed to contain matter in that form.     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

Atmospheric residence time of CH3Br estimated from the junge spatial variability relation

The atmospheric residence time for methyl bromide (CH3Br) has been estimated as 0.8 +/- 0.1 years from its empirical spatial variability relative to C2H6, C2Cl4, CHCl3, and CH3Cl. This evaluation of the atmospheric residence time, based on Junge's 1963 general proposal, provides an estimate for CH3Br that is independent of source and sink estimates. Methyl bromide from combined natural and anthropogenic sources furnishes about half of the bromine that enters the stratosphere, where it plays an important role in ozone destruction. This residence time is consistent with the 0.7-year value recently calculated for CH3Br from the combined strength estimates for its known significant sinks.     

Biodegradable Drug Delivery Systems for Gentamicin Release and Treatment of Synovial Membrane Infection

OBJECTIVE: This study investigated two biodegradable drug delivery systems (BDDS) for elution of gentamicin and elimination of synovial membrane infection. STUDY DESIGN: The effect of BDDS on control and infected synovial explants was determined. ANIMALS OR SAMPLE POPULATION: Synovial explants from four adult equine cadavers. METHODS: First, BDDS were placed in phosphate buffered saline for 14 days. Eluent was tested for gentamicin concentration (G) and bioactivity. Second, synovial explants were divided into four groups (n = 14/group): Group 1 (control); Group 2 (infected control) 405 cfu Staphylococcus aureus added at 6 hours; Group 3 (antibiotic BDDS [Ab-BDDS]) Ab-BDDS added at 24 hours; Group 4 (infected Ab-BDDS) 405 cfu S. aureus added at 6 hours, Ab-BDDS added at 24 hours. Both types of Ab-BDDS were used (n = 7/type/group). Explants were incubated in standard medium for 4 days. Medium was cultured and analyzed for (G) and hyaluronic acid concentration (HA). Explants were analyzed for viability and morphologic changes. RESULTS: The Ab-BDDS released >500 microg/mL of active gentamicin for 10 days. In Group 3, infection was eliminated within 24 hours, but histologic scores did not return to normal. Viability was significantly reduced by infection, but if eliminated, viability tended to return to normal. In Group 3, the Ab-BDDS had no significant effect on viability or (HA). Histopathologic scores were significantly higher for infected synovium. Infection, even if treated, significantly reduced (HA). CONCLUSIONS: Both Ab-BDDS eliminated infection within 24 hours. However, synovial morphology, viability and function did not return to normal. CLINICAL RELEVANCE: The Ab-BDDS may be useful for treatment of synovial membrane infection.     

Dietary resveratrol improves immunity but reduces reproduction of broodstock medaka <Emphasis Type="Italic">Oryzias latipes</Emphasis> (Temminck &amp; Schlegel)

Here, we investigated the effect of dietary resveratrol (20, 40, and 80 µg/g BW/day) on cell-mediated immunity (activity of spleen phagocytes and proliferative response of lymphocytes) and reproductive parameters (egg and sperm quality, i.e. fecundity—total number of eggs produced by individual fish, fertility, embryo survival, and hatching rate) in medaka. Fish fed feed with resveratrol at 40 and 80 µg/g BW/day had significantly higher metabolic activity and intracellular phagocyte killing activity than control. The proliferative lymphocyte activity of the fish from R80 group was greater by more than 20 % in comparison with the control group (P < 0.05). The percentage of macrophages (MO) and their mean fluorescence intensities (MFI) in R40 and R80 groups were significantly higher compared to C and R20 groups (P < 0.05). The differences in MO and MFI values ranged from 52.5 % (±1.5; R0 group) to 65.8 % (±1.6; R80 group) and from 23.2 (±1.4; R0 group) to 38.2 (±2.4; R80 group), respectively. Moreover, resveratrol at 80 µg/g BW/day decreased liver COX activity, i.e. 5.4 in R80 group and 7.9 in R0 group (P < 0.05). The motility parameters of the sperm obtained from the males fed feed supplemented with resveratrol at 80 µg/g BW/day exhibited the highest values except the linearity, which was lower as compared to the control (P < 0.05). The results indicate that diet supplemented with resveratrol at a dosage of 40 µg/g BW/day improves phagocyte killing ability and lymphocyte proliferation in broodstock and accelerates offspring hatch. Also, the results suggest that COX activity influences sperm and oocyte quality in fish; the presence of a COX inhibitor in the dose of 40 µg/g BW/day decreased the embryo survival.     

Comparison of the Johne''s absorbed EIA and the complement-fixation test for the diagnosis of Johne''s disease in cattle

A commercially available absorbed ELISA for the diagnosis of Johne's disease (JD) (paratuberculosis) in cattle, the Johne's Absorbed EIA, was compared with the conventional complement-fixation test (CFT) used in Australia. Stored plasma from 3 Victorian dairy herds with a history of JD, sera from specimens submitted from animals showing clinical signs of JD and sera from the US National Repository for Paratuberculosis Specimens were used to determine the sensitivity of each test. The EIA detected 48.8% of 43 Australian animals with subclinical JD, while the CFT detected only 12 (21.4%) of 56 subclinically affected cattle. Of 150 subclinically infected US cattle, the EIA detected 47.3% and the CFT detected 52.0%. The EIA detected 59.7% of animals which at the time of sampling were shedding Mycobacterium paratuberculosis in their faeces, but showed no clinical signs of JD, while the CFT detected 57.3%. The EIA correctly identified 88.2% of 136 histologically confirmed clinical cases, and the CFT detected 83.4%. The specificity of each test was determined by testing sera collected at slaughter from animals residing in a known JD-free area of Australia, and from samples from the US National Repository of Paratuberculosis Specimens collected from certified-free herds in Wisconsin. The EIA was found to have a specificity of 99.8% when 998 Australian animals were used as the test population, and 99.0% when 196 US animals were used. The specificity of the CFT using Australian samples was 96.9% and 95.2% using American samples.