Pharmacokinetic profiles of the two major active metabolites of metamizole, 4-methylaminoantipyrine (MAA) and 4-aminoantipyrine (AA), after intravenous injection in cats.

This study aimed to determine the pharmacokinetic profile of two active metabolites of metamizole (dipyrone), N-methyl-4-aminoanthypyrine (MAA) and 4-aminoanthypyrine (AA), after intravenous administration in cats. Eight healthy mixed-breed cats were intravenously administered metamizole (25 mg/kg). Blood samples were collected at predetermined time points for up to 48 h after administration. Information on behavioral changes in the animals and adverse effects was collected. Plasma aliquots were processed and analyzed using the ultra-performance liquid chromatography tandem mass spectrometry technique. A validated UPLC-MS/MS method was used to characterize the pharmacokinetics of MAA and AA. Salivation was identified as an adverse clinical sign. The mean maximal plasma concentrations of MAA and AA were 29.31 ± 24.57 µg/mL and 1.69 ± 0.36 µg/mL, with half-lives of around 4.98 and 14 h, respectively. The area under the plasma concentration curve values were 28.54 ± 11.33 and 49.54 ± 11.38 h*µg/mL for MAA and AA, respectively. The plasma concentration of MAA was detectable for up to 24 h and was smaller than AA. AA was detectable for >48 h. Results suggest that metamizole is converted into active metabolites in cats. Further PK/PD and safety studies should be performed before defining the dose or administration intervals for clinical use.

Morphology and immunolocalization of intertubular steroidogenic cell in mesonephros of Podocnemis expansa during gonadal differentiation.

Sex steroid hormones are critical in gonadal differentiation in turtles. The gonads are not the only organs responsible for producing these hormones during this phase. Mesonephros play an important role in steroidogenesis. The present study aimed to investigate the presence of steroidogenic cells in mesonephros of Podocnemis expansa during gonadal differentiation and to evaluate their morphology and ultrastructure. Ten embryos of P. expansa were collected from 5 nests on day 36 of incubation, during spawning period on an artificial beach. Embryos were extracted from eggs by slicing the shell and euthanized. They were dissected under a stereoscopic microscope to collect the gonad-mesonephro complex, in which were fixed and subsequently processed for light microscopy, immunohistochemistry and transmission electron microscopy analysis. During histological analysis was observed mesonephros has typical morphological structure. Immunohistochemistry showed immunoreaction to aromatase in cells of intertubular space. Confirming these findings, it was possible to observe a type of intertubular cell in several regions of mesonephro, being more predominant in region close to blood vessels, distal and proximal tubules. In ultrastructural analysis these cells were characterized by having a clear, large, and rounded nucleus with evident nucleolus and cytoplasm rich in electron-dense droplets. This study demonstrated for the first time the presence of cells with morphological, immunohistochemical and ultrastructural characteristics similar to steroid-producing cells in P. expansa mesonephrons, suggesting that this organ may contribute to gonadal differentiation in this species.

Development of a microfluidic system structured on a modified polydimethylsiloxane device for the selection of bovine epididymal spermatozoa.

Microfluidic systems are on the rise in several studies that evaluate reproductive cells. However, the material used for manufacturing can still be considered relatively expensive. The objective of this study was to develop a new microfluidic device, using a modified polydimethylsiloxane ((PDMS) Silpuran®), test its viability and carry out a selection of bovine sperm. Sperm was collected from epididymis (n = 10) and evaluated at different incubation times (60 min, 120 min, 180 min) to assess polydimethylsiloxane toxicity, where a tube was used as a control and the microfluidic device as treatment. An additional ten epididymis were used for the sperm selection test, which utilized four types of solutions: in vitro maturation medium (IVM) with and without oocyte, progesterone and saline solution (SS). The Percoll gradient was used as a control and the microfluidic device as treatment. The kinetic parameters of sperm were evaluated using the computer-assisted semen analysis (CASA). Morphology was performed with Bengal Rose, the integrity, and viability of the sperm using the hypoosmotic test and fluorescent microscopy probes, respectively. Mann-Whitney test was used in the first experiment, Kruskall-Wallis variance analysis tests with post hoc and Student-Newman-Keuls used in the second experiment. Regarding the non-toxic effects, most motility parameters demonstrated the superiority of the microfluidic device compared to the control. In the second experiment, the sperm showed equivalence between the microfluidic device and the Percoll gradient Silpuran® PDMS was not toxic to the cells and can be efficient for selecting bovine sperm, achieving better results in a medium for IVM with or without oocytes.

Validation of the Donkey Pain Scale (DOPS) for Assessing Postoperative Pain in Donkeys.

This study aimed to validate a scale for assessing acute pain in donkeys. Forty-four adult donkeys underwent castration after sedation with intravenous (IV) xylazine, induction with guaifenesin and thiopental IV, local anesthetic block, and maintenance with isoflurane. The scale was constructed from a pilot study with four animals combined with algetic behaviors described for equines. After content validation, the scale was evaluated in 40 other donkeys by three blinded and one reference evaluator, by means of edited videos referring to the preoperative and postoperative periods: before anesthesia, 3-4 h after recovery from anesthesia, 5-6 h after recovery from anesthesia (2 h after analgesia with flunixin-1.1 mg/kg, dipyrone-10 mg/kg, and morphine-0.2 mg/kg) IV, and 24 h after recovery. Content validity, sensitivity, specificity, and responsiveness of behaviors were investigated to refine the scale. Intra- and inter-evaluator reliabilities were investigated by the weighted kappa coefficient, criterion validity by comparing the scale with the visual analog scale (VAS), internal consistency by Cronbach's α coefficient, item-total correlation by the Spearman coefficient, and intervention point for rescue analgesic by the receiver operating characteristics curve and Youden index. The scale showed very good intra-evaluator reliability (0.88-0.96), good to moderate (0.56-0.66) inter-evaluator reliability, responsiveness for all items, good criterion validity vs. VAS (0.75), acceptable internal consistency (0.64), adequate item-total correlation, except for head position and direction, and according to the principal component analysis, good association among items. The accuracy of the point for rescue analgesic was excellent (area under the curve = 0.91). The rescue analgesic score was ≥ 4 of 11 points. The scale can diagnose and quantify acute pain in donkeys submitted to castration, as the instrument is reliable and valid, with a defined intervention analgesic score.

Pharmacokinetic properties of tramadol and M1 metabolite in Northeast Brazilian donkeys (Equus asinus).

There is currently little information available on the pharmacokinetics and pharmacodynamics of the analgesic opioid tramadol when used in the veterinary medicine of domestic species. In this study, we aimed to determine the pharmacokinetics of tramadol and its active metabolite M1 following intravenous administration of 2 (T2) and 4 (T4) mg/kg to Northeast Brazilian donkeys. Tramadol and M1 plasma levels were quantified using a validated liquid chromatography-tandem mass spectrometry method. We found that plasma levels of tramadol and M1 were higher than those reported as clinically meaningful in humans for at least 3 hr. However, the pharmacokinetic parameter calculation corrected by dose analysis identified no proportional increase with dose for the AUC of tramadol (T2: 2,663 ± 1,827 vs. T4: 2,964 ± 1,038 ng*h/ml) and M1 (T2: 378 ± 237 vs. T4: 345 ± 142 ng*h/ml). This finding appears to be attributable to a significant increase in clearance and a reduction in the terminal half-life of tramadol. The frequency of adverse effects observed at the higher dose indicates that 2 mg/kg administered intravenously would be suitable for donkeys. Clinical studies are required to determine the implications of these observations regarding the pharmacodynamic response to tramadol in Northeast Brazilian donkeys.

Rescue of caprine fetal ovaries, vitrification and follicular development after xenotransplantation in two immunodeficient mice models.

Domestic and wild goats are very susceptible animals to predation, specially when pregnancy occurs. This study aimed to evaluate the use of goat fetal ovarian tissue for vitrification followed by xenotransplantation and fresh xenotransplantation in two immunosuppressed mice models (C57BL/6 SCID and Balb-C NUDE). Goat fetus ovaries were collected in slaughterhouses, divided into small cortical pieces and were destined for fresh xenotransplantation (FX) and cryopreservation followed by xenotransplantation (CX). Five recipients from each lineage were used for FX and 10 animals from each lineage for CX. The mice were euthanized after 65 postoperative days, and the transplants were collected for microscopic assessment. The blood plasma was collected for estradiol measurement. Independently of mice strain, all recipients presented complete estrus cycle in FX and 80% after CX groups. Follicles were observed at all development stages without morphological changes. The volume density and total vessel surface observed in the transplants were different (p <0.01) between groups. The estradiol levels in the recipients did not differ (p <0.05) among the treatments. Thus, it is possible to activate the preantral follicles in the ovaries of fetuses by optimizing germplasm utilization and conservation of domestic and endangered wild goats that are in predatory situations, undesirable drowning or accidental death, since provided conditions for xenotransplantation are performed.

Equine chorionic gonadotrophin improved vascularization of feline ovarian tissue xenografted into immunosuppressed mice.

The objective of this study was to evaluate effects of eCG on vascularization and development of feline ovarian tissue xenografted to immunosuppressed mice. Feline ovarian fragments (∼1 mm3) were transplanted under the renal capsule of 20 adult, ovariectomized, C57BL/6 SCID female mice. At 45 d after transplantation, 10 mice (controls) were euthanized and the remainder given 10 IU of eCG (and sacrificed 48 h later). Transplants were recovered immediately after death, fixed, sectioned, and stained with periodic acid-Schiff (PAS). Fragment volume (Cavallieri principle) and vascularization were assessed. Mean xenotransplant volume for control and treatment groups was 0.17 ±â€¯0.03 and 0.37 ±â€¯0.13 mm3, respectively (P = 0.0952); vascular volume density, 30.3 ±â€¯11.3 and 49.1 ±â€¯8.9% (P = 0.0281); surface density, 4.1 ±â€¯2.4 and 6.2 ±â€¯1.7 µm-1 (P = 0.2222); and vessel total surface, 0.63 ±â€¯0.24 µm2 and 2.28 ±â€¯1.05 µm2 (P = 0.0079). In conclusion, eCG significantly increased vascular volume density of xenotransplanted ovarian tissue and improved its development.

Monitoramento do ciclo estral de fêmeas equinas por meio de citologia vaginal, ultrassonografia e dosagem hormonal / Monitoring equine estrous cycle through vaginal cytology, ultrasonography and hormone dosage / Monitoreo del ciclo estral de hembras equinas por medio de citología vaginal, ultrasonido y dosis hormonal

O ciclo estral é a sincronia entre eventos comportamentais, anatômicos e endócrinos que resultam na ovulação, e pode ser dividido em fase lútea e fase folicular. A identificação das fases do ciclo estral da égua pode ser acompanhada por meio de várias biotécnicas reprodutivas como, por exemplo, citologia vaginal classificando os diversos tipos de células do epitélio vaginal, ultrassonografia para avaliação da dinâmica folicular e a dosagem hormonal no plasma sanguíneo ou das fezes do animal para caracterizar a fase do ciclo estral que o animal possivelmente se encontra. Sendo assim, o objetivo desta revisão foi discutir a fisiologia do ciclo estral de éguas, a fim de favorecer novas pesquisas relacionadas à biotécnicas reprodutivas para equinos...

The estrous cycle is the synchrony of behavioral, anatomical and endocrine events that result in ovulation. It can be divided into luteal and follicular phases. The identification of the stages in the estrous cycle of mares can be accomplished through several reproductive biotechnologies, such as, for instance, vaginal cytology classifying the different types of cells in the vaginal epithelium, follicular dynamics evaluated through ultrasound examination, and hormone dosage in blood plasma or feces from the animal to characterize the likely estrous cycle phase. Thus, the objective of this review is to discuss the physiology of the estrous cycle in mares in order to encourage new research related to reproductive biotechnologies for horses...

El ciclo estral es la sincronía entre eventos de comportamiento, anatómicos y endocrinos que resultan en la ovulación, y se puede dividir en fase lútea y fase folicular. La identificación de las etapas del ciclo estral de la yegua puede ser acompañada a través de varias biotécnicas reproductivas como, por ejemplo, citología vaginal, clasificando los diferentes tipos de células del epitelio vaginal, ultrasonido para evaluación de la dinámica folicular y la dosificación hormonal en el plasma sanguíneo o de las heces del animal para caracterizar la fase del ciclo estral que el animal posiblemente se encuentra. Así, el objetivo de esta revisión ha sido examinar la fisiología del ciclo estral de yeguas, con el fin de fomentar nuevas investigaciones relacionadas con las biotecnologías reproductivas para equinos...