Eduardo Gutiérrez-Blanco

Postoperative analgesic effects of either a constant rate infusion of fentanyl, lidocaine, ketamine, dexmedetomidine, or the combination lidocaine-ketamine- dexmedetomidine after ovariohysterectomy in dogs

OBJECTIVE To evaluate the postoperative analgesic effects of a constant rate infusion (CRI) of either fentanyl (FENT), lidocaine (LIDO), ketamine (KET), dexmedetomidine (DEX), or the combination lidocaine-ketamine-dexmedetomidine (LKD) in dogs. STUDY DESIGN Randomized, prospective, blinded, clinical study. ANIMALS Fifty-four dogs. METHODS Anesthesia was induced with propofol and maintained with isoflurane. Treatments were intravenous (IV) administration of a bolus at start of anesthesia, followed by an IV CRI until the end of anesthesia, then a CRI at a decreased dose for a further 4 hours: CONTROL/BUT (butorphanol 0.4 mg kg(-1), infusion rate of saline 0.9% 2 mLkg(-1) hour(-1)); FENT (5 μg kg(-1), 10 μg kg(-1) hour(-1), then 2.5 μg kg(-1) hour(-1)); KET (1 mgkg(-1) , 40 μg kg(-1) minute(-1), then 10 μg kg(-1) minute(-1) ; LIDO (2 mg kg(-1), 100 μg kg(-1) minute(-1), then 25 μg kg(-1) minute(-1)); DEX (1 μgkg(-1), 3 μg kg(-1) hour(-1), then 1 μg kg(-1) hour(-1)); or a combination of LKD at the aforementioned doses. Postoperative analgesia was evaluated using the Glasgow composite pain scale, University of Melbourne pain scale, and numerical rating scale. Rescue analgesia was morphine and carprofen. Data were analyzed using Friedman or Kruskal-Wallis test with appropriate post-hoc testing (p < 0.05). RESULTS Animals requiring rescue analgesia included CONTROL/BUT (n = 8), KET (n = 3), DEX (n = 2), and LIDO (n = 2); significantly higher in CONTROL/BUT than other groups. No dogs in LKD and FENT groups received rescue analgesia. CONTROL/BUT pain scores were significantly higher at 1 hour than FENT, DEX and LKD, but not than KET or LIDO. Fentanyl and LKD sedation scores were higher than CONTROL/BUT at 1 hour. CONCLUSIONS AND CLINICAL RELEVANCE LKD and FENT resulted in adequate postoperative analgesia. LIDO, CONTROL/BUT, KET and DEX may not be effective for treatment of postoperative pain in dogs undergoing ovariohysterectomy.

Frequency and Type of Renal Lesions in Dogs Naturally Infected with Leptospira Species

The aim of this study was to determine the frequency and type of renal lesions associated with positive titers against Leptospira sp. in a stray dog population. Three hundred fifty pairs of kidneys and an equal number of serum samples were collected from dogs captured by the dog pound of Merida, Yucatan, Mexico. Euthanasia of dogs was performed following the regulations of the Official Mexican Health Ministry (NOM‐033‐ZOO‐1995). Serum samples were evaluated with the microscopic agglutination test, and tissue samples were processed and fixed in paraffin. After staining with hematoxylin and eosin, the frequency of renal lesions was determined and classified. As an additional evaluation, samples with interstitial nephritis were stained by the Warthin–Starry method in order to observe the presence of spirochete forms that could be morphologically compatible with Leptospira spp. We found that 98% of cases presented at least one type of lesion. The main histological lesions found were mesangial proliferative glomerulonephritis (MPGN) in 63.7% (n= 223), mesangial proliferative glomerulonephritis and interstitial nephritis (MPGN+IN) in 34% (n= 119), nephrosclerosis in 0.57% (n= 2), mesangial glomerulonephritis in 0.28% (n= 1), and interstitial nephritis (IN) in 0.28% (n= 1). Thirty‐four percent (n= 122) of the dogs were seropositive to Leptospira sp., mainly against serovar canicola. Among dogs with IN (alone or associated with MPGN) (n= 120), 49.1% were seropositive to Leptospira sp., but only 17% of them showed spirochete forms compatible with the bacteria. A statistical association between seropositive dogs and the presence of MPGN+IN was determined (P < 0.0001; odds ratio 2.7, confidence interval 1.7–4.5). We concluded that the frequency of renal lesions found in this study is high and L. canicola is probably the most common circulating serovar in dogs from this area. Dogs that have been in contact with Leptospira spp. have a higher risk of developing renal lesions of the type MPGN+IN.

Lidocaine, Dexmedetomidine and Their Combination Reduce Isoflurane Minimum Alveolar Concentration in Dogs

The effects of intravenous (IV) lidocaine, dexmedetomidine and their combination delivered as a bolus followed by a constant rate infusion (CRI) on the minimum alveolar concentration of isoflurane (MACISO) in dogs were evaluated. Seven healthy adult dogs were included. Anaesthesia was induced with propofol and maintained with isoflurane. For each dog, baseline MAC (MACISO/BASAL) was determined after a 90-minute equilibration period. Thereafter, each dog received one of the following treatments (loading dose, CRI): lidocaine 2 mg kg−1, 100 µg kg−1 minute−1; dexmedetomidine 2 µg kg−1, 2 µg kg−1 hour−1; or their combination. MAC was then determined again after 45- minutes of treatment by CRI. At the doses administered, lidocaine, dexmedetomidine and their combination significantly reduced MACISO by 27.3% (range: 12.5–39.2%), 43.4% (33.3–53.3%) and 60.9% (46.1–78.1%), respectively, when compared to MACISO/BASAL. The combination resulted in a greater MACISO reduction than the two drugs alone. Their use, at the doses studied, provides a clinically important reduction in the concentration of ISO during anaesthesia in dogs.

Effects of Lidocaine, Dexmedetomidine, or Their Combination on the Minimum Alveolar Concentration of Sevoflurane in Dogs

ABSTRACT The aim of this study was to determine the effects of lidocaine (LIDO) and dexmedetomidine (DEX) or their combination (LIDO–DEX), administered by constant-rate infusion (CRI), on the minimum alveolar concentration (MAC) of sevoflurane in dogs. Seven healthy mongrel dogs were used with a 2-week washout interval between treatments in this study. Anesthesia was induced with propofol and maintained with sevoflurane in oxygen, and MAC of sevoflurane was determined after 90 min equilibration period in the dogs (SEV-MACBASAL). Then, sevoflurane MAC was determined again in the dogs after 45 min equilibration period of one of the following treatments: an intravenous loading dose of lidocaine 2 mg/kg followed by 6 mg/kg/hr CRI (SEV-MACLIDO); an intravenous loading dose of dexmedetomidine 2 µg/kg followed by 2 µg/kg/hr CRI (SEV-MACDEX); or their combination (SEV-MACLIDO-DEX). These SEV-MACs were determined in duplicate. Data were analyzed using ANOVA and post hoc Tuckey test when appropriate. The SEV-MACBASAL was 1.82 ± 0.06%, SEV-MACLIDO was 1.38 ± 0.08%, SEV-MACDEX was 1.22 ± 0.10%, and SEV-MACLIDO-DEX was 0.78 ± 0.06%. The CRI administration of lidocaine, dexmedetomidine and their combination produced a significant reduction in the MAC of sevoflurane by 26.1 ± 9.0% (P<0.0001), 43.7 ± 11.8% (P<0.0002) and 54.4 ± 9.8% (P<0.0001), respectively. The MAC reduction was significantly greater after the CRI combination of lidocaine and dexmedetomidine when compared with lidocaine CRI (P<0.0001) or dexmedetomidine CRI treatments (P<0.025).

Common Lesions in the Female Reproductive Tract of Dogs and Cats

Reproductive lesions are commonly seen in small animal practice. Lesions in the ovaries, uterus, and vagina may seriously influence normal reproductive capacity of dogs and cats and may put at risk the general health of the patients. The objective of this article is to give the veterinary practitioner a current and concise guide to the clinical signs, intraoperative changes, diagnosis, and treatment/management of lesions in the reproductive tract of the bitch and queen commonly seen in practice.

Plant products and secondary metabolites with acaricide activity against ticks

The present review documents the results of studies evaluating the acaricidal activity of different plant products and secondary metabolites against ticks that are resistant and susceptible to conventional acaricides. Studies published from 1998 to 2016 were included. The acaricidal activity of plant extracts, essential oils and secondary compounds from plants have been evaluated using bioassays with ticks in the larval and adult stages. There is variable effectiveness according to the species of plant and the concentrations used, with observed mortalities ranging from 5 to 100% against the Rhipicephalus (Boophilus), Amblyomma, Dermacentor, Hyalomma, and Argas genera. A number of plants have been reported to cause high mortalities and/or affect the reproductive capacity of ticks in the adult phase. In the majority of these trials, the main species of plants evaluated correspond to the families Lamiaceae, Fabaceae, Asteraceae, Piperaceae, Verbenaceae, and Poaceae. Different secondary metabolites such as thymol, carvacrol, 1,8-cineol and n-hexanal, have been found to be primarily responsible for the acaricidal activity of different essential oils against different species of ticks, while nicotine, dibenzyldisulfide and dibenzyltrisulfide have been evaluated for plant extracts. Only thymol, carvacrol and 1,8-cineol have been evaluated for acaricidal activity under in vivo conditions. The information in the present review allows the conclusion that the secondary metabolites contained in plant products could be used as an alternative for the control of ticks that are susceptible or resistant to commercial acaricides.

Parasitic Zoonoses in Humans and Their Dogs from a Rural Community of Tropical Mexico

A cross-sectional study was made on 89 inhabitants and their dogs from a rural community of Yucatan, Mexico, to determine the serological prevalence of some zoonotic parasitic agents. Samples were taken to monitor the presence and intensity of infection with gastrointestinal parasites in dogs. In humans, the serological prevalence of T. canis, T. gondii, and T. spiralis was 29.2%, 91.0%, and 6.7%, respectively. No associations were found between positive cases and studied variables. From the total of blood samples taken from dogs, 87 (97.6%) were seropositive to T. gondii; only 52 viable fecal samples were collected from dogs of which 46.2% had the presence of gastrointestinal parasites with low to moderate intensity; from those, 12% had the presence of T. canis. This study demonstrates the presence of the studied zoonotic agents in the area particularly T. gondii which suggest a common source of infection in dogs and humans and a high number of oocyts present in the environment. Preventive measures must be designed towards good prophylactic practices in domestic and backyard animals (T. canis and T. spiralis). Contaminated sources with T. gondii (food and water) should be further investigated in order to design effective control measures.

Effects of papaya seeds extract on the sperm characteristics of dogs.

The effect of chloroform extracts from seeds of the papaya plant (Carica papaya) on the spermatic characteristics of dogs was evaluated at doses of 50, 100 and 150 mg/kg, Groups 1, 2, and 3, respectively. Structural and ultrastructural changes in sperm cells and testicular parenchyma were also evaluated, and possible side effects were noted. Significant reductions in sperm concentration and motility were observed starting from Days 60 and 75, respectively, in all treated groups (P<0.05), but no azoospermia was noted. A mild osmotic diarrhea occurred in dogs from Group 3 (150 mg/kg), although blood variables were within the normal range of a clinically healthy dog. Arrested spermatogenesis was observed in the seminiferous tubules of all treated groups, and vacuolization and signs of Sertoli cell degeneration were detected in all treated groups, particularly in Group 3 (150 mg/kg). Selective damage to Sertoli cells induced by the extract occurred in all treated groups independently of the extract concentration. Alteration of the epididymal environment may reduce the motility of sperm cells, considering that their structure was normal. Sperm characteristics in treated animals were considered to be similar to those of sub-fertile dogs. However, these effects may be temporary, and dogs may recover normal sperm characteristics when the extract is withdrawn.

Effects of Chloroformic Extracts from Washed and Unwashed Papaya Seeds (Carica papaya) on the Sperm Concentration of Dogs

Papaya seeds (Carica papaya Linn) have been found to have a significant effect on sperm characteristics in some mammals, including humans, but no studies have investigated the effects on dogs. In the present study, a significant decrease in sperm concentration was observed in a group of dogs treated with extracts from washed papaya seeds, but no decrease was observed in the group of dogs treated with non-washed seeds. An important effect of extract components from washed seeds such as fatty acids is probably involved in the reduction of sperm production because of Sertoli cell damage, as has been suggested for langur monkeys. Dilution of the active components in the non-washed papaya seeds or interference with some of the components may reduce the expected effect on spermatogenesis. This first report on the effects of a chloroformic extract of papaya seeds in dogs suggests that an increased dose is necessary to achieve azoospermia.

Stray Dog Population in a City of Southern Mexico and Its Impact on the Contamination of Public Areas

To assess the risk of zoonotic pathogen transmission as function of stray dog presence and health status, a cross-sectional study was carried out in a large city of southern Mexico that lacks comprehensive strategies for the control of stray canine populations. The photographic capture-recapture method was used to estimate the density of dogs/km2. In the same way, dog feces from 14 public parks of the city were collected to determine the prevalence and intensity of infection with gastrointestinal parasites. The canine population was estimated between 65 and 80 thousand dogs, with a population density of 1,081 dogs/km2, mostly males (71.4%). A high proportion of dogs (72.3%) were found to be in good body condition score (BCS 3). The person:dog ratio was 2.3. The likelihood of being in the BCS 2 category was lower in areas with a higher density of dogs. All feces collected from the parks contained eggs of intestinal parasites, most of them with a medium (42.9%) to high (35.7%) infection intensity, notably Ancylostoma caninum. It was recorded that cases with a low-intensity of GI infection showed polyparasitism (35.7%) associated with A. caninum. There is a large population of stray dogs that roam freely in the streets of Campeche city with access to sources of food, which is reflected by their good BCS, and dogs do not have access to preventive medicine programs (de-worming) and thus contaminate public parks with feces with significant parasitic egg loads of zoonotic importance.