牧草害虫优势天敌伞裙追寄蝇飞行中代谢相关酶活性的变化

昆虫在飞行过程伴随着较高的代谢速率和能源物质消耗.为明确伞裙追寄蝇飞行肌对能源物质的利用,测定了与能源物质代谢相关的5种酶,即3-磷酸甘油醛脱氢酶(GAPDH)、3-磷酸甘油脱氢酶(GDH)、3-羟酰辅酶A脱氢酶(HOAD)、乳酸脱氢酶(LDH)和柠檬酸合酶(CS)的活性变化.结果表明:GAPDH活性在吊飞过程中呈先升...     

Dose-response relationship of atracurium besylate in the halothaneana-esthetised pig

The dose response relationship for the intermediateacting non-depolarising muscle relaxant, atracurium besylate in the pig was determined using evoked electromyography. An incremental dose technique was used in seven Large White/Landrace crossbred pigs anaesthetised with nitrous oxide and halothane. ED50 and ED95 were 510 ± 87 μg kg⁻¹ and 1150 ± 270 μg kg⁻¹, respectively. Although these values may represent an overestimate, they provide a reasonable guideline for the use of atracurium by veterinary anaesthetists.     

Effects of inhibition of nitric oxide synthase on systemic arterial pressure and renal vascular resistance in cats

These studies were undertaken to examine the systemic and renal effects of the pharmacological inhibition of endothelium-derived nitric oxide (EDNO) in cats. In six healthy cats, the intravenous infusion of nitro-L-arginine at a dose of 100 μg kg⁻¹ bodyweight min⁻¹ resulted in a marked increase (P<0·001) in mean arterial pressure from the control value of 116·7 ± 4·6 mmHg to 154·2 ± 6·8 mmHg and an increase (P<0·05) in renal vascular resistance from the control value of 3·69 ± 0·33 mmHg min ml⁻¹ to 6·83 ± 1·15 mmHg min ml⁻¹. The increase in renal vascular resistance was generalised, with comparable increments in preglomerular and postglomerular vascular resistance. Mean values for glomerular capillary pressure (61·1 ± 61·9 vs 1·9 ± 1·6 mmHg), calculated from the sum of arterial colloid osmotic pressure plus proximal tubule stop-flow pressure, did not change in response to the infusion of nitro-L-arginine. However, there was a marked reduction in renal blood flow (29·4 ± 3·1 to 16·9 ± 2·3 ml min⁻¹, P<0·01) and glomerular filtration rate (5·22 ± 0·57 to 3·52 ± 0·45 ml min⁻¹, P<0·01). These results provide evidence that EDNO plays an important role in the basal regulation of systemic arterial blood pressure and renal haemodynamics in cats.     

Pharmacokinetics of doxycycline in sheep after intravenous and oral administration

The pharmacokinetics of doxycycline were investigated in sheep after oral (PO) and intravenous (IV) administration. The IV data were best described using a 2- (n = 5) or 3- (n = 6) compartmental open model. Mean pharmacokinetic parameters obtained using a 2-compartmental model included a volume of distribution at steady-state (V_ss) of 1.759 ± 0.3149 L/kg, a total clearance (Cl) of 3.045 ± 0.5264 mL/kg/min and an elimination half-life (t_1/2β) of 7.027 ± 1.128 h. Comparative values obtained from the 3-compartmental mean values were: V_ss of 1.801 ± 0.3429 L/kg, a Cl of 2.634 ± 0.6376 mL/kg/min and a t_1/2β of 12.11 ± 2.060 h. Mean residence time (MRT_0−∞) was 11.18 ± 3.152 h. After PO administration, the data were best described by a 2-compartment open model. The pharmacokinetic parameter mean values were: maximum plasma concentration (C_max), 2.130 ± 0.950 μg/mL; time to reach C_max (t_max), 3.595 ± 3.348 h, and absorption half-life (t_1/2k01), 36.28 ± 14.57 h. Non-compartmental parameter values were: C_max, 2.182 ± 0.9117 μg/mL; t_max, 3.432 ± 3.307 h; F, 35.77 ± 10.20%, and mean absorption time (MAT_0–∞), 25.55 ± 15.27 h. These results suggest that PO administration of doxycycline could be useful as an antimicrobial drug in sheep.     

Comparative pharmacokinetics of an injectable cephalexin suspension in beef cattle

This study describes and compares the pharmacokinetics of a single 7.5 mg/kg dose of cephalexin monohydrate oil-based 20% suspension after its administrations to six cows by the intramuscular (i.m.) and subcutaneous (s.c.) routes, and to five calves by the i.m. route. Significantly (P < 0.05) higher peak plasma concentrations (5.6 ± 0.79 μg/ml versus 3.93 ± 1.24 μg/ml) and lower half-life (1.81 ± 0.56 h versus 4.21 ± 0.82 h) and mean residence time (4.12 ± 1.07 h versus 6.63 ± 0.85 h) were obtained after i.m. administration when compared to the s.c. administration to cows. No differences were found between pharmacokinetic parameters calculated for cows and calves. Cephalexin plasma concentrations remained above 0.5–0.75 μg/ml for 11–14 h and 8–9 h after the s.c. and i.m. administrations, respectively. Thus, route of administration may be an important issue to be considered when calculating dosage schedules for successful treatments and safe withdrawal times for veterinary medicines.     

Reference Values on Serum Biochemical Parameters of Brazilian Donkey (Equus asinus) Breed

Seventeen serum biochemical variables were determined in 40 donkeys of the Brazilian breed (34 females and 6 males) aged from 3 to 19 years. Mean ± standard deviation (SD) (minimum–maximum) values, obtained by automated analysis, were as follows: glucose, 58.35 ± 10.40 (44.00–90.00) mg/dL; cholesterol, 88.41 ± 9.86 (73.58–124.26) mg/dL; serum protein, 6.82 ± 0.40 (6.00–7.52) g/dL; albumin, 3.13 ± 0.21 (2.65–3.69) g/dL; creatinine, 1.80 ± 0.14 (1.51–2.19) mg/dL; urea, 24.25 ± 5.37 (14.12–34.39) mg/dL; lactate, 20.10 ± 4.58 (12.99–33.47) mg/dL; aspartate aminotransferase (AST), 295.81 ± 62.79 (173.71–466.07) IU/L; creatine kinase (CK), 158.00 ± 76.94 (51.69–440.33) IU/L; γ-glutamil-transferase (GGT), 45.82 ± 13.34 (26.17–86.38) IU/L; lactate dehydrogenase (LDH), 576.02 ± 156.32 (213.53–1162.81) IU/L; alkaline phosphatase (AP), 345.36 ± 65.90 (227.25–490.16) IU/L; calcium (Ca), 8.54 ± 0.18 (8.19–8.90) mg/dL; phosphorus (P), 2.76 ± 0.38 (1.99–3.97) mg/dL; chloride (Cl), 106.05 ± 3.20 (99.00–112.00) mEq/L; sodium (Na), 121.50 ± 4.14 (116.00–132.00) mEq/L; and potassium (K), 3.70 ± 0.42 (2.80–4.40) mEq/L. Comparisons of biochemical ranges obtained for the Brazilian donkey breed with reference ranges for other donkey breeds suggested that most values were similar. Biochemical values determined in the present study serve as reference ranges for donkey populations and can be used for health control and diagnosis of diseases.     

Saliva collection and relationship between lactate concentration in blood and saliva of exercising horses

The aims of this study were to examine whether sufficient volumes of saliva can be collected for lactate analysis in exercising horses and to establish the relationship between blood and saliva lactate concentration. Saliva was collected for 30 seconds after exercise with a commercially available cotton swab Salivette^® from two sites: At the height of the 3rd premolar in the maxilla (upper site) and under the tongue at the level of the frenulum linguae (lower site). Blood was taken from the jugular vein. Horses were submitted to two types of standardized exercise on a treadmill: Continuous exercise and an incremental exercise step test.The average (± standard deviation) volume of saliva sampled at the upper site was 390±280 μl, and at the lower site 450±310 μl. The lactate concentration in saliva after continuous exercise sampled at the upper site was 2.21±1.97 mmol/l, and at the lower site it was 3.76±2.31 mmol/l. There was no significant correlation between lactate concentration in blood and upper site saliva, and blood and lower site saliva after continuous exercise and during incremental exercise step test.     

A Modified Screening Method for Estimating Erythrocyte Glucose Phosphate Isomerase

A fluorimetric method to estimate erythrocyte glucose phosphate isomerase is described. Five μl of blood is added to 100 μl of water. Ten μl of the resulting hemolysate is incubated with a reaction mixture (200 μl) containing Tris-HCl buffer pH 8.0, 20 μmoles, MgCl₂ 2 μmoles, nicotinamide adenine dinucleotide phosphate 0.08 μmoles, glucose-6-phosphate dehydrogenase 0.2 EU and fructose-6-phosphate 0.12 μmoles. After ten minutes of 25°C 20 μl of the mixture is added to 2 ml of 0.01 M phosphate buffer pH 7.4 and the nicotinamide adenine dinucleotide phosphate fluorescence determined. Two ml of water was added to the remaining reaction mixture and the hemoglobin concentration determined at 410 nm. The technique is primarily designed for use with small amounts of blood, of widely varying activity, from various animal species.     

Dose-related antinociceptive effects of intravenous buprenorphine in cats

The dose-related antinociceptive effects of intravenous (IV) buprenorphine were evaluated in cats. Thermal (TT) and mechanical threshold (MT) devices were used for nociceptive stimulation. After baseline threshold recordings, buprenorphine was administered IV (0.01, 0.02 or 0.04 mg/kg; B1, B2 and B4, respectively) in a randomised, blinded and cross-over study. Data were analysed by ANOVA (P < 0.05) using 95% confidence intervals (CI). TT increased 15, 30, 45 min and 1 (5.2 ± 2.7 °C), 2, 3 and 4 h after B1; 15, 30, 45 min and 1 (5.1 ± 3.9 °C) and 2 h after B2, and 15, 30, 45 min and 1 (5.4 ± 3.3 °C), 2, 3, 6 and 8 h after B4. MT increased 15 and 45 min after B2 (260 ± 171 mmHg), and 30 (209 ± 116 mmHg) and 45 min and 1 and 2 h after B4. At 45 min, MT values were significantly higher after B2 compared to B1 (P < 0.05). With MT, B2 and B4 produced more antinociception and longer duration of action than B1, respectively. No dose response to thermal stimulation was detected.     

Responses to condensed tannins of flowering sulla (Hedysarum coronarium L.) grazed by dairy sheep: Part 1: Effects on feeding behaviour, intake, diet digestibility and performance

The concentration of condensed tannins (CT) in sulla (Hedysarum coronarium L.) is moderate and overall regarded as beneficial. However, the intake of this forage can reduce diet digestibility, particularly during flowering phase. An experiment was run to assess the effect of CT on feeding behaviour, intake, diet digestibility and performance of dairy sheep rotationally grazing sulla at flowering phase. Twenty-four late-lactating sheep were blocked in two homogeneous groups and submitted to the following treatments: i) twice daily drenching with 200 g/day of a 50% w/v water solution of an anti-tannic substance, polyethylene glycol, group PEG; ii) twice daily drenching with 200 g/day of water, group CON (Control group). All the sheep rotationally grazed as a flock two sulla plots from April to June (8 weeks in total). Sward height, herbage mass, botanical and chemical composition of the herbage were measured at the beginning and the end of each grazing period. The feeding behaviour (3 sheep per group) was continuously monitored for 24 h in 6 weeks using the IGER behaviour recorders. Herbage DM intake (DMI), dietary DM digestibility (DMD) and apparent CP digestibility (CPD) were estimated on 8 sheep per group by the n-alkane method. On average, PEG group had longer total grazing (503 ± 12 vs 460 ± 12 min, P < 0.05) and eating time (425 ± 13 vs 391 ± 13 min, P < 0.07) than CON group. Moreover PEG group showed shorter inter-meal intervals (41 ± 3 vs 52 ± 3, min, P < 0.05) and higher number of daily meals than CT-exposed group (24 ± 1 vs 19 ± 1 min, P < 0.01). The herbage DMI was not affected by the treatment whereas DMD (74.60 ± 3.48 vs 58.30 ± 3.01%), and CPD (60.14 ± 4.83 vs 38.21 ± 4.83%) were both increased by PEG administration (P < 0.05) confirming the negative effect of sulla CT on these variables. Milk yield tended to be higher in PEG than CON (1331 ± 45 vs 1205 ± 59 ml, P < 0.11). Milk protein content was similar between groups while milk fat content was higher in CON than PEG ewes (6.61 ± 0.15 vs 6.11 ± 0.15%, P < 0.05), being the reverse true for milk urea (46.04 ± 1.27 vs 53.04 ± 0.76%, P < 0.001). To conclude, this experiment shows that when sulla is grazed at flowering as monoculture, dietary CT can exert negative effects on DM and CP apparent digestibility, in this study partially counterbalanced by a better metabolic utilisation of the nutrients up-taken.     

Differential responses in anterior pituitary luteinizing hormone (LH) content and LHβ- and α-subunit MRNA, and plasma concentrations of LH and testosterone, in bulls treated with the LH-releasing hormone agonist deslorelin

Anterior pituitary gland contents of LH and LHß- and α-subunit mRNAs, and circulating concentrations of LH and testosterone, were determined in bulls treated with the LH-releasing hormone (LHRH) agonist deslorelin. Brahman (Bos indicus) bulls (14-month-old) were allocated to two groups and received the following: Control (n = 5), no treatment; Deslorelin (n = 4), four deslorelin implants (approximately 200 μg total deslorelin/day) for 36 d. Plasma concentrations of LH were higher in bulls treated with deslorelin on Day 1, had returned to typical levels by Day 8, and did not differ for control bulls and bulls treated with deslorelin from Day 8 to Day 29. Pituitary content of LH on Day 36 was reduced (P < 0.001) in bulls treated with deslorelin (33 ± 4 ng/mg) compared with control bulls (553 ± 142 ng/mg). Relative pituitary content of LHß-subunit mRNA was also reduced on Day 36 in bulls treated with deslorelin (Control, 0.65 ± 0.10; Deslorelin, 0.22 ± 0.04; P = 0.003). However, α-subunit mRNA relative content did not differ (Control, 0.73 ± 0.15; Deslorelin, 1.06 ± 0.12; P > 0.05). Plasma concentrations of testosterone were increased over the period of the experiment in the bulls treated with deslorelin compared with control bulls. This is the first demonstration of reduced pituitary content of LHß-subunit mRNA and LH, and unaltered content of α-subunit mRNA, in bulls treated with LHRH agonist. This was associated with apparently typical plasma concentrations of LH and elevated plasma testosterone. The anterior pituitary in bulls treated with LHRH agonist, therefore, undergoes classical desensitization and downregulation, but plasma LH and testosterone are not suppressed.     

Morphometric study of the recurrent laryngeal nerve in young ‘normal’ horses

Quantitative measurements were made on cross-sectional preparations of the distal part of the recurrent laryngeal nerve (RLN) from nine young mixed-breed horses to establish reference values for the total number of myelinated fibres, mean fibre diameter and percentage of thickest fibres (over 9·5 gm) and to delineate diameter distribution curves. The total number of myelinated fibres, mean fibre diameter and percentage of thickest fibres for the left RLN were significantly lower than those of the right RLN (P<0–005). The distribution of fibres was unimodal. The fibre diameter ranged from 1 μm to 17 μm. Approximately, 95 per cent of fibres had a diameter larger than 5 μm.     

ATP loss with exercise in muscle fibres of the gluteus medius of the thoroughbred horse

Muscle ATP loss with exercise has implications both to the causes of fatigue and muscle damage. To study this at the single muscle fibre level, five trained thoroughbred horses performed consecutive 90 second gallops on an inclined treadmill followed by a final gallop to fatigue. Biopsies of the m. gluteus medius were taken at rest, post-exercise and during 24 hour recovery. Blood lactate was 20·0 mmol litre⁻¹ or more, and plasma NH₃ 300–800 μmol litre⁻¹, following the final gallop. Minimal changes occurred in the plasma markers, and . ATP loss with exercise was 32·2 ( 12·2) per cent. Following exercise single fibre contents showed a much broader distribution than at rest, with contents in some close to zero. Following five and 24 hour recovery, however, frequency distribution curves were close to those seen at rest. There was no difference in the ATP contents of types I, IIa and IIb at rest of with exercise or recovery. The results pointed to marked heterogeneity between individual fibres in their biochemical response with exercise, independent of fibre type.     

The cardiopulmonary effects of clenbuterol when administered to dorsally recumbent halothane-anaesthetised ponies - failure to increase arterial oxygenation

Clenbuterol (0·8 μg kg ⁻¹ intravenously) was investigated in ponies (small horses) anaesthetised with acepromazine, detomidine and thiopentone, then halothane in oxygen alone (hyperoxic group) or with nitrous oxide (hypoxic group). Following instrumentation, ponies were placed in dorsal recumbency for 60 minutes, clenbuterol (both groups) or a saline control (hyperoxic group) given, and cardiopulmonary parameters monitored for a further 60 minutes. In the hyperoxic group, clenbuterol administration resulted in a transitory (<five minutes) 15 per cent fall in arterial blood pressure and 78 per cent rise in intramuscular blood flow. Heart rate increased from a mean of 42 (SD 4) to 54 (12) beats per minute, the rise being significant for 15 minutes. Cardiac index increased from 2·1 (0·7) to 3·-9 (0·7) litres m⁻² and remained significantly elevated for the remainder of the measurement period. Cardiovascular changes in the hypoxic group were similar. 30 minutes after clenbuterol administration, PaO₂ had changed non-significantly from 32·.3 (19·2) to 33·.4 (17) kPa in the hyperoxic group and from 7·9 (1·8) to 8·.6 (1·3) kPa in the hypoxic group. The study concludes that under these experimental conditions, clenbuterol does not cause significant improvement in arterial oxygenation, but its cardiovascular effects are minimal or advantageous.     

Pathology and residues in veal calves treated experimentally with clenbuterol

Six veal calves were medicated with clenbuterol at 20 μg kg bodyweight⁻¹ day⁻¹ for 42 days before they were slaughtered, to evaluate the lesions and residues in target organs. Compared with six unmedicated calves the most noticeable changes were tracheal dilatation, decreased uterine weight, slight mucous hypersecretion in the uterus and vagina and depletion of liver glycogen. The highest concentrations of clenbuterol (62 to 128 ng/g⁻¹) were recorded in the choroid/retina, and the aqueous humour had the lowest concentration (0·5 to 2·4 ng ml⁻¹). The residue concentrations were higher than the maximum residue level set for clenbuterol (0·5 ng g⁻¹)     

Alternative methodologies to estimate ingestion of caecotrophes in growing rabbits

This study was carried out in order to estimate caecotrophe intake in growing rabbits by three existing procedures: caecotrophes collection after collar fitting, urinary purine derivatives (PD) excretion and microbial ¹⁵N-lysine incorporation. In a first experiment sixteen New Zealand White male rabbits were divided in three groups receiving the same diet, but supplemented with ¹⁵NH₄Cl in the first group (T₁: 6 rabbits). The second group (T₂: 6 rabbits) was also fed the labelled diet but only during the last ten days of the fattening period when animals were fitted a neck collar to prevent caecotrophy. The third group (T₃: 4 animals) received the basal diet and was used as control. In two additional trials the daily contribution to urinary excretion of endogenous purine compounds (469 ± 50.8 μmol/W^0.75) and creatinine excretion (807 ± 127.6 μmol/W^0.75) were determined. The highest estimation of microbial nitrogen recycling was obtained by the urinary PD method (0.79 ± 0.096 g/d), whereas caecotrophes collection and ¹⁵N-lysine incorporation methods showed similar values (0.49 ± 0.049 and 0.45 ± 0.015 g/d, respectively). Our results seem to indicate an overestimation of microbial nitrogen recycling in growing rabbits by PD methodology, while neck collar fitting procedure gave similar results, although more variable than microbial ¹⁵N-lysine incorporation.     

Lincomycin and spectinomycin in the treatment of breeding rams with semen contaminated with ureaplasmas

Ureaplasma species were isolated from semen samples collected sequentially from one Awassi and three Assaf breeding rams. Each ram was injected subcutaneously with an aqueous solution of lincomycin and spectinomycin for five consecutive days at a dose equivalent to 4·5 mg kg⁻¹ lincomycin and 9·0 mg kg⁻¹ spectinomycin daily. Serum and semen samples were collected at intervals during the treatment and assayed for lincomycin. No Ureaplasma species were isolated from semen samples collected during the course of the treatment and at intervals for 17 days after the last treatment. The concentration of lincomycin in semen ranged from 0·51 μg ml⁻¹ four hours after treatment to 0·08 μg ml⁻¹ 24 hours after treatment, and these levels were three to nine times higher than the corresponding serum concentrations.     

Generation of Airborne Particles from Different Bedding Materials Used for Horse Keeping

Among other factors (eg, feed), bedding material has an important effect on stable air quality with respect to airborne particle formation. This study was designed to establish which material is suited to create an improved stable environment for horses. First, the following materials were analyzed under standardized conditions in a laboratory experiment: wheat straw, dry wood shavings, hemp shives, linen shives, wheat straw pellets, paper cuttings (unprinted newspaper). The second investigation was carried out under in situ conditions in which three of these bedding materials (wheat straw, wood shavings, and straw pellets) were analyzed under practical conditions. In both experiments, airborne particle concentrations were detected online with the gravimetrically measuring analyzer TEOM 1400a (Rupprecht & Patashnick Co., Franklin, MA). In the laboratory experiment, the TEOM was equipped successively with different inlets to measure the particle fractions PM₁, PM_2.5, PM₁₀, and PM₂₀. During the in situ experiment, only the fraction PM₁₀ was detected. In the laboratory experiment, hemp and linen had the highest generation of airborne particles in all fractions. The lowest particle generation was detected with straw pellets. Results of the in situ investigation supported results of the laboratory experiment with respect to mean particle generation of straw pellets. With an average of 111.2 ± 149.2 μg/m³, it was significantly lower than the mean particle generation of wheat straw with 227.5 ± 280.8 μg/m³. The particle generation of wood shavings had an average of 140.9 ± 141.9 μg/m³ and also was significantly lower than the generation by wheat straw. An activity-correlated variation of particle concentrations was found. In conclusion, taking both experiments into consideration, straw pellets seemed to be suitable for horse stables, to promote an improvement in the stable climate in relation to airborne particle formation.     

Reference values on hematologic parameters of the Brazilian donkey (Equus asinus) breed

Thirteen hematologic measurements were performed on 38 healthy donkeys of the Brazilian breed (32 females and 6 males) aged 3 to 19 years. Mean ±SD (minimum-maximum) values were as follows: red blood cells (RBC) 6.82 ± 0.67 (5.46−8.17) × 10⁶/μL; packed cell volume (PCV) 37.63 ± 2.76 (32.00−44.00) %; hemoglobin (Hb) 12.87 ± 0.98 (10.70−14.50) g/dL; mean corpuscular volume (MCV) 55.45 ± 4.06 (48.90−62.70) fL; mean corpuscular hemoglobin (MCH) 18.85 ± 1.14 (17.40−21.60) pg; mean corpuscular hemoglobin concentration 34.20 ± 1.24 (31.50−36.40) g/dL; white blood cells (WBC) 8.22 ± 1.49 (4.60−11.50) × 10³/μL; bands 1.77 ± 2.00 (0.00−9.00) %; segmented neutrophils 41.18 ± 5.98 (30.50−53.20) %; lymphocytes 50.53 ± 6.25 (35.30−63.50) %; monocytes 1.57 ± 1.30 (0.00−4.60) %; eosinophils, 4.64 ± 2.17 (1.00−10.00) %; basophils 0.33 ± 0.58 (0.00−2.90) %. It was demonstrated that values of some blood parameters of the Brazilian donkey breed were similar to results obtained for other donkey breeds. The results of this study serve as reference ranges for donkey populations and can be useful for health control, which in turn helps in the diagnosis and prognosis of diseases.

Introduction

Blood examination has been performed for several reasons: as a screening procedure to assess general health; as an adjunct to patient's infection; and to evaluate the progress of certain disease states.[1] However, there are important differences in physiology, behavior, and management that influence the common diseases encountered in donkeys. Successful diagnosis and treatment often depend on recognizing these differences. [2] Unfortunately, a limited number of observations have been reported on the hematologic values for donkey breeds and populations and these studies are far from complete. [3, 4, 5, 6, 7, 8 and 9] Hematologic variation values for donkey breeds and populations should be associated with the age, sex, and the time of sampling in relation to exercise, geographic, and nutritional factors. Perhaps some of the variations observed among different authors were also associated with different techniques and methods. [4]Apart from the investigations by Perdigão de Oliveira et al,[3] Gacek et al, [10] and Mori et al, [11] we could find no published record of blood values of the Brazilian donkey breed. The aim of this investigation was to determine reference ranges for hematologic analyses in the Brazilian donkey breed to establish a baseline for further scientific and clinical use.

Materials and methods

The material for the present study consisted of 38 adult donkeys of the Brazilian breed (32 females and 6 males), ranging between 3 and 19 years of age (mean ±SD: 8.3 ± 3.5 years), from the Estação Experimental de Colina do Instituto de Zootecnia da Secretaria de Agricultura do Estado de São Paulo, and kept under similar feeding and management conditions. All animals were apparently healthy, and they were handled carefully to reduce any possible effects of stress on the parameters analyzed.Blood samples were draw from the jugular vein into 5 mL evacuated glass tubes containing EDTA as anticoagulant. Blood smears were prepared immediately after being collected from whole blood and then were air-dried. The collected blood samples were immediately stored at 4°C and processed within 6 hours.RBC and WBC counts were performed using an electronic counter (Serono Baker). Hb concentration was determined by the cyanmethemoglobin method. PCV was determined after the blood had been transferred to microhematocrit tubes and centrifuged at 10,000 g for 5 minutes. MCV, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were calculated from PCV, Hb concentration, and RBC count.[1] Blood smears were stained with modified May-Grunwald Giemsa stain for determination of the differential WBC count. At least 200 WBCs were counted for differential WBC determinations.All analyses were performed within the Departamento de Clinica Médica da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo.Data analysis was performed using a statistical software (Graph Pad InStat version 3.01, 32 bit for Windows 95/NT). Each parameter was tested for normality applying the Kolmogorov and Smirnov methods. The reference ranges for the hematologic analyses were given as mean ±SD and the interval from minimum and maximum values.Unpaired t-tests were used to determine the effect of sex (female versus male) on hematologic values, for data normally distributed. If data did not seem to be normally distributed, non-parametric tests (Mann-Whitney U test) were used. The level of statistical significance was set at P < .05.

Results

Reference ranges of hematologic constituents of the blood of the Brazilian donkey breed determined in the current study are shown in Table 1 and Table 2. Most of the values had Gaussian distribution (P < .10). Only basophils did not seem to be normally distributed (P < .05). Comparisons of hematologic ranges of the Brazilian donkeys with other donkey breeds and populations are shown in Table 1 and Table 2.     

Dextran sulfate protects porcine but not bovine cultured endothelial cells from free radical injury

Previous studies demonstrated that the polyanion dextran sulfate (DS) protects rat coronary and porcine aortic endothelium (PAE) from oxygen-derived free radical (OFR) injury due to hydrogen peroxide (H₂O₂) or xanthine/xanthine oxidase (X/XO). To determine if DS has a similar protective effect in bovine aortic endothelium (BAE) and bovine brain microvascular endothelium (BBME), H₂O₂ or X/XO was added to confluent cultures. Cell injury was assessed 1 d later by measuring the percentage of viable cells (by trypan blue exclusion) and the release of lactate dehydrogenase (LDH) into the medium. After H₂O₂ doses of 6.0 mM for BAE and BBME and 0.8 mM for PAE, and after X doses of 10 μM and XO doses of 0.3 U/mL for all cell types, approximately 50% of cells were viable. Cultures were pretreated with DS (0.001 to 500 μg/mL) 24 to 26 h prior to H₂O₂ or X/XO exposure. Pretreatment at concentrations of 0.5, 5, and 50 μg/mL significantly increased the percentage of viable cells and reduced LDH release in cultures of PAE, but not BAE or BBME, treated with H₂O₂. Similarly, pretreatment with DS concentrations of 5 and 50 μg/mL significantly increased the percentage of viable cells and reduced LDH release in cultures of PAE, but not BAE or BBME, treated with X/XO. Thus, DS protected porcine but not bovine endothelium. Catalase (10 U/mL) increased the percentage of viable cells and reduced LDH release in H₂O₂-treated BAE and BBME, suggesting that DS likely acts by a different mechanism and does not neutralize H₂O₂. These results suggest that the protective effect of DS on OFR-injured endothelium is species-dependent.