Efficacy assessment of an intramammary treatment with a new recrystallized enrofloxacin vs ceftiofur and parenteral enrofloxacin in dairy cows with nonsevere clinical mastitis.

A recrystallized form of enrofloxacin as dehydrate-HCl (enro-C) was assessed for bacteriological and clinical cure efficacies in Holstein-Friesian cows affected of nonsevere clinical mastitis. Treatments were enro-Csusp (n = 81), treated with a pharmaceutical suspension of enro-C/quarter; group enro-Cpd (n = 80) treated as above, but using enro-C powder suspended in water; group CF (n = 65), treated with ceftiofur HCl/quarter; and group enroR (n = 66), treated with standard enrofloxacin solution (5 mg/kg, intramuscular). Cows had a mean milk production of 31 L/day and were 2-3 lactational periods old. Treatments were administered every 24 hr for 3 days. Groups treated with enro-C exhibited statistically significant (p > .05) better clinical cure as compared to groups treated with CF or enroR (95.06%, 96.25%, 67.79%, and 57.55%, for enro-Csusp , enro-Cpd , CF, and enroR , respectively). In contrast, probability of bacteriological cure was not statistically different among treatments. Yet, the outstanding clinical and bacteriological cure rates obtained for enro-C for nonsevere cases of mastitis is superior to previously reported data for parenteral enrofloxacin and other antibacterial-intramammary treatments. Impact of using enro-C on the rate and pattern of bacterial resistance, somatic cell counts and milk electric conductivity, must be studied. Also, the use of enro-C for complicated cases of mastitis should be studied and milk withdrawal times must be accurately established.

Ixodicide activity of Eysenhardtia polystachya against Rhipicephalus (Boophilus) microplus.

The objective of this study was to evaluate the acaricidal effect of 2 compounds extracted from Eysenhardtia polystachya in vitro, namely coatlines and matlalines. Each extract was obtained by aqueous extraction in a nitrogen atmosphere. Engorged adult females of an amitraz-resistant strain of Rhipicephalus (Boophilus) microplus were used to produce larvae and to carry out the adult immersion test (AIT), while larvae were assayed using the larval packet test (LPT). After exposure to coatlines or matlalines, the mortality of larvae and engorged females, as well as the reproductive parameters of adult ticks were assessed. Coatlines were not lethal against larvae and did not decrease reproductive parameters. Conversely, matlalines showed a 90 to 100% efficacy against adults and larvae at all concentrations tested and a reduction of 76.41 to 80.64% oviposition and a 48.02 to 54.86% reduction in egg hatchability. Therefore, the acaricidal activity of matlalines was more efficient. Further studies are required to elucidate both the mode of action of matlalines as well the structure-activity relationships responsible for the observed differential efficacy between these 2 related isoflavans against the cattle tick.

Serum and tissue concentrations of doxycycline in broilers after the sub-cutaneous injection of a long-acting formulation.

1. The antibacterial agent doxycycline hyclate (Dox) is usually administered to broilers in drinking water or as a feed supplement. Parenteral injection is not the usual route for administration, so a long-acting formulation (Dox-LA) was tested to evaluate if serum concentrations can achieve the pharmacokinetic/pharmacodynamic (PK/PD) ratios regarded as adequate for the drug. 2. A poloxamer-based matrix was used to provide Dox-LA. Serum and tissue concentrations of Dox vs time were determined in two day-old broilers after subcutaneous (SC) injection of Dox-LA or oral administration of a single bolus of aqueous Dox (Dox-PO), at a dose of 20 mg/kg. Weight gain, feed conversion rate, haematological variables, aspartate aminotransferase and alanine aminotransferase activities, blood urea and creatinine were determined and compared for Dox-LA with Dox-PO and non-medicated controls. 3. Dox-LA had a high relative bioavailability (1200%). Maximum serum concentrations were not statistically different (5·1 ± 1·1 µg/ml for Dox-LA and 6·1 ± 1.4 µg/ml for Dox-PO), but half-life of Dox-LA was much greater than the value obtained for Dox-PO (73·0 ± 0·9 h and 2·0 ± 0·02 h, respectively). Tissue concentrations were higher, and stayed higher for longer periods in the Dox-LA group. 4. In conclusion, considering the minimum effective serum concentration against Mycoplasma spp is 0·5 µg/ml, a dose-interval of 180 h can be achieved with Dox-LA, but only for 24 h after Dox-PO. Better PK/PD ratios for Dox-LA should result in improved clinical outcomes compared with Dox-PO.

Pharmacokinetics of disodium fosfomycin in broilers and dose strategies to comply with its pharmacodynamics versus Escherichia coli.

The objective of this study was to determine, in broilers, which modality of disodium fosfomycin (DF) administration and at what dose the best pharmacokinetic (PK) profile could be obtained, taking as reference a 110 field bacterial strains of Escherichia coli minimum inhibitory concentration survey. The DF was administered via drinking water either ad libitum or at a higher concentration having 1 h of water restriction to build up thirst in the birds (loading dose). Dosages tested were 10, 20, 40, and 80 mg/kg per administration, either once or twice daily. Birds included were 24-d-old Cornish broilers randomly assigned to 16 groups of 200 birds per group and 3 replicates per group. The PK of DF was determined after ad libitum administration of either a single- or double-loading dose or after an initial loading dose followed by ad libitum medication. Also, PK after i.v. administration was studied in separate groups. Serial blood samplings were performed in all groups. Serum obtained was analyzed for DF and a possible active metabolite by means of a microbiological agar diffusion assay. The DF showed a short elimination half-life (approximately 2 h after oral loading administration) with a rapid clearance (1.23 to 1.42 mL/kg per h). Apparent volume of distribution-area under the curve values were also low (10 and 80 mg/kg=0.25 L/kg and 0.22 L/kg, respectively). Considering a minimum inhibitory concentration level that inhibited 90% of total strains of 8 µg/mL for E. coli, it is concluded that single-loading administration at 10, 20, 40, and 80 mg/kg complies poorly with sustained serum concentrations over a dosing interval of 24 h. Doses of 10 and 20 mg/kg twice a day also were insufficient to attain therapeutic concentrations. Useful serum concentrations of DF to treat outbreaks of susceptible E. coli require an initial loading dose of 40 mg/kg, followed by an ad libitum medication of 40 mg/kg 8 h later (80 mg/kg per d).

Electroencephalographic evaluation of gold wire implants inserted in acupuncture points in dogs with epileptic seizures.

The purpose of this study was to evaluate both, clinically and with electroencephalographic (EEG) recordings, the effect of gold wire implants in acupuncture points in dogs with uncontrolled idiopathic epileptic seizures. Fifteen dogs with such diagnosis were enrolled in the study. A first EEG recording was performed in all dogs under anaesthesia with xylazine (1mg/kg) and propofol (6 mg/kg) before the treatment protocol, and a second EEG was performed 15 weeks later. Relative frequency power, intrahemispheric coherence available through EEG, number of seizures and seizure severity were compared before and after treatment using a Wilcoxon signed-rank test. There were no significant statistical differences before and after treatment in relative power or in intrahemispheric coherence in the EEG recording. However, there was a significant mean difference in seizure frequency and seizure severity between control and treatment periods. After treatment, nine of the 15 dogs (60%) had at least a 50% reduction in seizures frequency during the 15 weeks established as follow-up of this treatment.

Evaluation of the carcinogenic effects of furazolidone and its metabolites in two fish species.

The major metabolite from the use of furazolidone (FZD) in mammals, birds and fish is 2,3-dihydro-3-cyanomethyl-2-hydroxy-5-nitro-1alpha, 2-di(2-oxo-oxazolidin-3-yl)iminomethyl-furo[2,3-beta]furan, also called 3-amine-2-oxazolidone (AOZ). A minor metabolite was identified as N-(5-amine-2-furfuryliden)-3-amine-2-oxazolidone (FOZ). To assess the potential carcinogenicity of FZD and the metabolic mixture of AOZ/FOZ, 11 mg FZD/kg feed/day was fed for 12 weeks to mollies (Poecilia formosa), an ornamental fish species prone to develop tumors. The rate of tumors was quantified and defined both in mollies and their offspring. Then, some fish was made into fishmeal and incorporated into fish food at 500 g of meal/kg of food and fed to other mollies for 12 weeks. The rate of tumors was assessed. A similar trial design was carried out in tilapia fish (Oreochromis niloticus) by adding 50 mg FZD/kg to the feed for 90 days. All animals were placed in glass fishponds under controlled laboratory conditions. Each week, a significant biomass was collected from both groups to assess the macroscopic and histopathological changes. All mollies developed melanohistiocytomic tumors in the liver and other organs. Offspring from surviving mollie females stimulated to breed showed no changes compared to control animals. None of the mollies fed with the mollie-meal food contaminated with AOZ/FOZ developed tumors. Neither tilapia medicated with FZD nor tilapia fed with tilapia-meal contaminated with AOZ/FOZ developed tumors. These results do not support the established viewpoint that FZD must be banned from trophic chains based on its potential carcinogenic properties.

Treatment of wobbler syndrome in dogs with electroacupuncture.

Based on favorable experiences with acupuncture for the treatment of hind limbs paralysis, lumbo-sacral alterations, and other spinal cord problems; a clinical trial, involving 40 dogs affected with wobbler syndrome was carried out. Patients were graded in three categories according to the severity of each case and then randomly divided in two groups. Both groups contained all three grades. Group 1 (20 dogs) was treated using orthodox medical and surgical interventions, while Group 2 (20 dogs) were treated mainly with electroacupuncture, and in few cases with surgical intervention as well. The study was carried out in a three-year period. Acupuncture treatments were given every other day delivering 150 to 300 mVolts at 125 Hz, equivalents to approximately 20 microAmps, in ten acupuncture points per treatment. Deep needle insertion was used. Overall per cent success in Group I was only 20%, while in group II the corresponding value was 85%. The number of acupuncture treatments required to achieve full recovery in Group II was dependent upon the severity of the case, as follows: Grade I: 18.5 +/- 2.5; Grade II: 25 +/- 5.4; and Grade III: 34 +/- 6.7 (r = 0.962). No adverse effects were observed with acupuncture. The use of this technique is proposed for large-scale clinical trials.

The use of acupuncture-like electrical stimulation for wound healing of lesions unresponsive to conventional treatment.

Based on previous experimental evidence suggesting improved healing of wounds treated with electrical stimulation, we conducted a clinical trial with patients seeking alternative medicine after unsuccessful conventional medical treatment. Electricity was delivered in two forms: (1) For wounds with extensive loss of tissue and/or those that had failed to heal spontaneously, electrical stimulation was delivered via subcutaneously inserted needles surrounding the wound edges and applying a dose charge of 0.6 coulombs/cm2/day; (2) in second degree burn injuries, lesions were covered with gauze soaked in a 10% (w/v) sterile saline solution and the same dose of electricity was applied as for (1). Forty-four patients were treated with electrical stimulation of the skin; 34 in group (1) and 10 in group (2). Following electrostimulation in all patients in both groups healing proceeded in a thoroughly organized manner, almost regardless of the severity of the type of wound or burn treated. Advantages and limitations of this technique are discussed.

The influence of pulsed electrical stimulation on the wound healing of burned rat skin.

Electrostimulation of wounds caused healing to proceed in a thoroughly organized manner. A trial using rats subjected to second degree burns was conducted to evaluate, under scanning electron microscopy (SEM), the healing capabilities of skin to which an antiseptic (iodine) and referred electrical stimulation were applied. Untreated, unharmed skin was also studied as control. Images obtained using SEM revealed that only the repaired skin of the electrostimulated group had an appearance similar to that of the control skin (kappa = 1), and that the overall appearance of the repaired skin was compatible with a well organized healing process.

A comparative trial of garlic, its extract and ammonium-potassium tartrate as anthelmintics in carp.

While fish chemotherapy is not a common practice in México, folk medicine is usually well accepted by fish farmers. Empirical knowledge suggested that garlic should have anthelmintic properties. Various trials were carried out in Cyprinus carpio infested with Capillaria sp., using minced garlic and its extracts. An empirical concentration of 200 mg/l of minced garlic showed the greatest activity against the above mentioned worms (100%). The hexane extract in equivalent amounts showed a 75% effectiveness while the aqueous extract showed no anthelmintic effect. The addition of ammonium-potassium tartrate to the tanks (1.5 mg/l) gave a 86% anthelmintic effectiveness.