Measurement for breath concentration of hydrogen and methane in horses.

This study concerns the establishment of a simple testing method for breath concentration of hydrogen and methane in horses. Twenty-eight healthy thoroughbreds and 24 Arabians were used. Breath samples were collected using one-minute closed circulatory respiration through an aluminum bag filled with 10 liters of pure oxygen, which was mounted on the subjects by means of a face mask. Breath samples obtained, were analyzed by gas chromatography. A significant correlation in both hydrogen and methane levels was observed for samples collected at separate times. These findings confirmed the usefulness of our approach for testing breath concentrations of hydrogen and methane in horses.     

Evaluation of carbohydrate malassimilation and intestinal transit time in cats by measurement of breath hydrogen excretion

Techniques for the measurement of breath hydrogen excretion have been evaluated in dogs and the breath hydrogen test has been shown to be useful for clinical diagnosis and as a research tool. A simple method was developed for collection of expired air and measurement of breath hydrogen concentrations in cats, which enabled demonstration of carbohydrate malassimilation. Breath hydrogen concentrations were measured in healthy cats after food was withheld and after xylose and lactulose administration. Breath samples were collected by use of an open flow system with the cat confined in an acrylic plastic chamber. Breath hydrogen excretion did not exceed 0.53 ml of hydrogen/h in cats not fed. Breath hydrogen concentrations after the ingestion of xylose, a pentose sugar given orally at 0.75 g/kg of body weight, were not significantly higher from those of cats not fed. After ingestion of 3.35 g of lactulose, a nonabsorbable disaccharide, breath hydrogen excretion increased and breath hydrogen concentrations were significantly higher by 45 minutes (P less than 0.05) and 60 minutes (P less than 0.01) from breath hydrogen concentrations measured in cats not fed and after xylose administration. Administration of lactulose at an increased dosage resulted in further significant (P less than 0.01) increases in breath hydrogen excretion. In this study, mouth-to-cecum transit times were variable. A mean +/- SEM mouth-to-cecum transit time of 86 +/- 6 minutes was calculated from measurement of breath hydrogen excretion after oral administration of 3.35 g of lactulose.(ABSTRACT TRUNCATED AT 250 WORDS)     

Purification of cattle oviduct specific proteins and their effect on in vitro embryo development

The purpose of this study was to determine the effect of oviduct specific proteins as a media supplement for in vitro embryo development in cattle. The proteins were extracted from oviducts of cows and precipitated by ammonium sulfate (30%, 40%, 50% and 60%) followed by dialysis in 50 mM Tris–HCl (pH 7.0) buffer. The dialyzed proteins were fractionated into acidic, basic and neutral fractions using SP sephadex cation exchange and DEAE sephadex anion exchange column chromatography respectively. Cow oviduct specific proteins (cOSPs) constituting all the extracted proteins were used as media supplement in three different concentrations (10, 50 and 100 μg/ml) for in vitro maturation, fertilization and culture (IVMFC) of cow oocytes. Acidic, basic and neutral (unbound) fractions were also used as media supplement in three different concentrations (10, 30 and 50 μg/ml) for IVMFC. Cumulus oocytes complexes were collected from slaughterhouse ovaries, washed thoroughly and cultured in maturation media for 24 h in 5% CO₂ at 38.5 °C with maximum humidity. In vitro matured oocytes were co-incubated with in vitro capacitated sperm in Fert-BO media at 38.5 °C for 18 h in 5% CO₂. The fertilized oocytes were washed and cultured in embryo development media for cleavage. After 40–42 h cleavage was observed and embryos were put in the replacement media for further development. The cleavage rates (%) for cOSPs were observed as 68.24±2.46, 69.28±2.05, 61.77±0.93 and 42.62±1.31 at concentrations of 0, 10, 50 and 100 μg/ml respectively. Rates of blastocyst stage development were 14.49±3.61, 21.17±2.77, 14.66±1.06 and 11.98±1.84. These results indicate that addition of cOSP at10 μg/ml increased blastocyst formation as compared to other concentrations (0, 50 and 100 μg/ml). Although acidic, basic and neutral fractions seemed to have no major effect on cleavage rate, but both acidic and neutral fraction of oviduct specific proteins improved the cleavage rate at 30 μg/ml concentration and basic fraction improved the blastocyst formation at 10 μg/ml concentration.     

Current and future uses of breath analysis as a diagnostic tool

The analysis of exhaled breath is a potentially useful method for application in veterinary diagnostics. Breath samples can be easily collected from animals by means of a face mask or collection chamber with minimal disturbance to the animal. After the administration of a 13C-labelled compound the recovery of 13C in breath can be used to investigate gastrointestinal and digestive functions. Exhaled hydrogen can be used to assess orocaecal transit time and malabsorption, and exhaled nitric oxide, carbon monoxide and pentane can be used to assess oxidative stress and inflammation. The analysis of compounds dissolved in the aqueous phase of breath (the exhaled breath condensate) can be used to assess airway inflammation. This review summarises the current status of breath analysis in veterinary medicine, and analyses its potential for assessing animal health and disease.     

Insights into the mechanism by which kisspeptin stimulates a preovulatory LH surge and ovulation in seasonally acyclic ewes: Potential role of estradiol

We have previously demonstrated that a constant intravenous infusion of kisspeptin (Kp) for 48 h in anestrous ewes induces a preovulatory luteinizing hormone (LH) surge followed by ovulation in approximately 75% of animals. The mechanisms underlying this effect are unknown. In this study, we investigated whether Kp-induced preovulatory LH surges in anestrous ewes were the result of the general activation of the whole gonadotropic axis or of the direct activation of central GnRH neurons required for the GnRH/LH surge. In the first experiment, a constant iv infusion of ovine kisspeptin 10 (Kp; 15.2 nmol/h) was given to 11 seasonally acyclic ewes over 43 h. Blood samples were taken every 10 min for 15 h, starting 5 h before the infusion, and then hourly until the end of the infusion. We found that the infusion of Kp induced a well-synchronized LH surge (around 22 h after the start of the Kp infusion) in 82% of the animals. In all ewes with an LH surge, there was an immediate but transient increase in the plasma concentrations of LH, follicle-stimulating hormone (FSH), and growth hormone (GH) at the start of the Kp infusion. Mean (± SEM) concentrations for the 5-h periods preceding and following the start of the Kp infusion were, respectively, 0.33 ± 0.09 vs 2.83 ± 0.49 ng/mL (P = 0.004) for LH, 0.43 ± 0.05 vs 0.55 ± 0.03 ng/mL (P = 0.015) for FSH, and 9.34 ± 1.01 vs 11.51 ± 0.92 ng/mL (P = 0.004) for GH. In the first experiment, surges of LH were observed only in ewes that also had a sustained rise in plasma concentrations of estradiol (E₂) in response to Kp. Therefore, a second experiment was undertaken to determine the minimum duration of Kp infusion necessary to induce such a pronounced and prolonged increase in plasma E₂ concentration. Kisspeptin (15.2 nmol/h) was infused for 6, 12, or 24 h in seasonally acyclic ewes (N = 8), and blood samples were collected hourly for 28 h (beginning 5 h before the start of infusion), then every 2 h for the following 22 h. Kisspeptin infused for 24 h induced LH surges in 75% of animals, and this percentage decreased with the duration of the infusion (12 h = 50%; 6 h = 12.5%). The plasma concentration of E₂ was greater in ewes with an LH surge compared to those without LH surges; mean (± SEM) concentrations for the 5-h period following the Kp infusion were, respectively, 2.23 ± 0.16 vs 1.27 ± 0.13 pg/mL (P < 0.001). Collectively, our results strongly suggest that the systemic delivery of Kp induced LH surges by activating E₂-positive feedback on gonadotropin secretion in acyclic ewes.     

Pharmacokinetics and bioavailability of a long-acting formulation of cephalexin after intramuscular administration to cats

The pharmacokinetic profile and bioavailability of a long-acting formulation of cephalexin after intramuscular administration to cats was investigated. Single intravenous (cephalexin lysine salt) and intramuscular (20% cephalexin monohydrate suspension) were administered to five cats at a dose rate of 10 mg/kg. Serum disposition curves were analyzed by noncompartmental approaches. After intravenous administration, volume of distribution (V_z), total body clearance (Cl_t), elimination constant (λ_z), elimination half-life (t_½λ) and mean residence time (MRT) were: 0.33 ± 0.03 L/kg; 0.14 ± 0.02 L/h kg, 0.42 ± 0.05 h⁻¹, 1.68 ± 0.20 h and 2.11 ± 0.25 h, respectively. Peak serum concentration (C_max), time to peak serum concentration (T_max) and bioavailability after intramuscular administration were 15.67 ± 1.95 μg/mL, 2.00 ± 0.61 h and 83.33 ± 8.74%, respectively.     

Breath hydrogen concentration and small intestinal malabsorption in calves

Breath hydrogen concentrations were measured to assess intestinal carbohydrate malabsorption in preruminating calves. Oral administration of 1.25 g of lactulose (a nonabsorbable carbohydrate)/kg to calves produced breath hydrogen concentrations significantly (P less than 0.001) higher than values determined after calves were fed milk and before the treatment was given. This indicates that, in the calf, fermentation of nonabsorbed carbohydrates results in increased breath hydrogen values. To induce small intestinal malabsorption, chloramphenicol was administered orally at 50 mg/kg, 2 times a day, to 5 calves for 3 days. Before therapy was started, each calf was fitted with a duodenal cannula to facilitate collection of intestinal mucosal biopsy samples during treatment. Chloramphenicol therapy significantly (P less than 0.001) increased breath hydrogen concentrations from those values measured after calves were fed milk alone. Concurrently, chloramphenicol administration significantly decreased intestinal villous length (P less than 0.001) and D-xylose absorption (P less than 0.05), compared with those values before treatment was given. These results demonstrate that decreased intestinal absorptive capacity is associated with an increase in breath hydrogen concentrations and that breath hydrogen may be useful in evaluating malabsorption in calves with naturally occurring enteric disease.     

Pharmacokinetics and bioavailability of moxifloxacin in buffalo calves

The pharmacokinetics of moxifloxacin were investigated in buffalo calves following a single intravenous and intramuscular administration of moxifloxacin (5 mg kg⁻¹ body wt.). Moxifloxacin concentrations in plasma and urine were determined by microbiological assay. Pharmacokinetic analysis of disposition data indicated that intravenous administration data were best described by a two compartment open model, whereas intramuscular administration data were best described by a one compartment open model. Following intravenous administration, the elimination half life (t_1/2β), volume of distribution (Vd_(area)) and total body clearance were 2.69 ± 0.14 h, 1.43 ± 0.08 L kg⁻¹ and 371.2 ± 11.2 ml kg⁻¹ h⁻¹, respectively. Following intramuscular administration, the absorption half life (t_1/2ka) was 0.83 ± 0.20 h. The systemic bioavailability (F) of moxifloxacin in buffalo calves was 80.0 ± 4.08%. Urinary excretion of moxifloxacin was less than 14% after 24 h of administration of drug. In vitro binding of moxifloxacin to plasma proteins of buffalo calves was 28.4 ± 3.77%. From the data of surrogate markers (AUC/MIC, C_max/MIC), it was determined in the buffalo calves that when administered by intravenous or intramuscular route at 5 mg kg⁻¹, moxifloxacin is likely to be effective against bacterial isolates with MIC ? 0.1 μg ml⁻¹.     

Determination of lactose and xylose malabsorption in preruminant diarrheic calves.

In preliminary studies feeding the poorly absorbed carbohydrate sorbitol at 2.3 g/kg body weight as an indication of maximal fermentative capacity failed to produce the expected large increase in breath hydrogen excretion but did produce a transient diarrhea in five out of six control calves. Twelve healthy control and eighteen diarrheic calves were fed lactose or D-xylose on consecutive days at 1.15 g/kg body weight and a concentration of 46 g/L. Breath and blood samples were collected at 1 h intervals from 0 to 7 h. After administration of lactose, there was a significant increase in breath hydrogen excretion in diarrheic versus control calves. The increase in plasma glucose concentrations was delayed in diarrheic calves but the area under the absorption curve was similar in control and diarrheic calves. After administration of D-xylose, breath hydrogen excretion did not increase significantly but plasma D-xylose concentrations were significantly reduced in diarrheic calves. The pathogens commonly isolated from the feces were Cryptosporidium species, rotavirus and coronavirus. The number of pathogens and the severity of the calves' acid-base deficit were not related to the severity of carbohydrate malabsorption. Decreased absorption of lactose and D-xylose may be the result of intestinal villous atrophy caused by viral or parasite infection. It was concluded that carbohydrate malabsorption rather than a specific lactose maldigestion is a significant problem in diarrheic calves. Diarrheic calves appear to digest and absorb lactose when fed in small amounts.     

Combined subcutaneous administration of ivermectin and nitroxynil in sheep: Age/body weight related changes to the kinetic disposition of both compounds

The effect of age/body weight in the plasma disposition kinetics of ivermectin (IVM) and nitroxynil (NTX) after their co-administration as a combined formulation to sheep was studied. Sixteen (16) male sheep were allocated into two experimental groups (n = 8 each): (a) high body weight (high bw) (18-20 months old), and (b) low body weight (low bw) (6-8 months old). Animals in both groups were subcutaneously (sc) treated with IVM (200 μg/kg) and NTX (10 mg/kg) using a commercially available combined formulation (Nitromectin^®, Lab. Ovejero, Spain). Blood samples were taken by jugular venopuncture before (time 0), at 2, 4, 8, 12 h and at 1, 2, 3, 5, 7, 10, 15, 20, 25, 35, 40, 50 and 60 days after administration. Recovered plasma was analysed to quantify IVM and NTX by HPLC. Higher IVM plasma concentrations were measured until 20 days post-administration in “low bw” compared to “high bw” animals, where IVM was recovered up to 35 days post-treatment. The IVM absorption process greatly differed between experimental groups. A significantly higher (p < 0.01) C_max (36.7 ± 7.52 ng/ml) value was obtained at a delayed (p < 0.05) T_max (48.0 ± 0.0 h) in light compared to heavy (C_max: 8.0 ± 0.80 ng/ml; at 34.0 h) body weight sheep. IVM elimination half-life and mean residence time were significantly shorter in light compared to heavy (older) sheep. NTX mean plasma concentrations were lower in “low bw” compared to those measured in “high bw” sheep, with elimination phases declining up to 60 d post-administration in both experimental groups. The NTX AUC value in “low bw” (1188.5 ± 122.6 μg day/ml) was significantly lower (p < 0.05) than that obtained in the “high bw” (oldest) animals (1735.0 ± 155.8 μg day/ml). Shorter NTX elimination half-life and mean residence time (p < 0.01) were obtained in the youngest (“low bw”) compared to the oldest (high bw) sheep. The work reported here assessed for the first time the disposition of IVM and NTX after their combinated injection to sheep, demonstrating that animal body weight/development greatly affects the kinetic behaviour of both anthelmintic drugs.     

Zona-free and with-zona parthenogenetic embryo production in goat (Capra hircus) — effect of activation methods, culture systems and culture media

Studies on parthenogenetic activation of oocytes are important to improve the efficiency of nuclear transfer as artificial activation of oocytes is an essential component of nuclear transfer protocol. The present study was carried out to investigate the effects of different activation methods, culture systems and culture media on in vitro development of zona-free and with-zona parthenogenetic embryos in goat. In case of zona-free parthenogenesis, there was a significant (p < 0.05) increase in cleavage rate and blastocyst yield when oocytes were activated by electrical pulse (76.29 ± 0.52% and 19.07 ± 0.39% respectively) than when Ca-ionophore was used for activation (63.45 ± 0.73% and 14.09 ± 0.65% respectively). The quality of blastocysts was evaluated by determination of cell number and by expression profile of pluripotent related gene Oct-4. No significant (p < 0.05) difference was found in quality of blastocysts produced by different activation methods. In culturing of zona-free parthenogenetic embryos, flat surface (FS) was proved to be the best system. A significant (p < 0.05) decrease in cleavage rate and blastocyst yield was found in Microdrop culture of zona-free embryos (43.67 ± 2.08% and 0.72 ± 0.72% respectively) in comparison to WOW of zona-free embryos (73.88 ± 1.70% and 15.51 ± 1.34% respectively) and FS of zona-free (75.14 ± 0.81% and 23.93 ± 2.71% respectively) as well as with-zona (72.16 ± 1.55% and 18.16 ± 0.68%) embryos. Zona-free flat culture system yielded significantly (p < 0.05) higher blastocyst rate than zona-free WOW system as well as with-zona flat culture system. The zona-free and with-zona parthenogenetic embryos were cultured in three different media — Research Vitro Cleave media from Cook® Australia (RVCL), Embryo Development Medium (EDM) and Modified Synthetic Oviductal Fluid (mSOF). In case of zona-free parthenogenesis, significant (p < 0.05) increase was found in blastocyst development rate in RVCL medium (18.61 ± 1.52%) than EDM (11.29 ± 0.77%) or mSOF (11.53 ± 1.86%). In case of with-zona parthenogenesis, RVCL medium and EDM were found superior to mSOF. The results of the study will be helpful to improve the efficiency of nuclear transfer in goat.     

Disposition of marbofloxacin in vulture (Gyps fulvus) after intravenous administration of a single dose

The pharmacokinetics properties of marbofloxacin were studied in adult Eurassian Griffon vulture after single-dose intravenous (IV) administration of 2 mg/kg. Drug concentration in plasma was determined by high-performance liquid chromatography and the data obtained were subjected to compartmental and non-compartmental kinetic analysis. Marbofloxacin presented a volume of distribution at steady-state (Vdss) of 1.51 ± 0.22 L and total plasma clearance (Cl) of 0.109 ± 0.023 L/h kg. The permanence of this drug was long in vultures (T_1/2λ = 12.51 ± 2.52 h; MRT_∞ = 13.54 ± 2.29 h). The optimal dose of marbofloxacin estimated is 2.73 mg/kg per day for the treatment of infections in vultures with MIC₉₀ = 0.2 μg/mL.     

Endogenous ghrelin released in response to endothelin stimulates growth hormone secretion in cattle

The purpose of this study was to evaluate whether circulating ghrelin and growth hormone (GH) concentrations in cattle are regulated by endothelin-1 (ET-1), endothelin-3 (ET-3), and secretin. Six Holstein steers (242 ± 1 d old, 280.5 ± 4.4 kg body weight [BW]; mean ± SEM) were allocated randomly in an incomplete Latin square design to receive each of 4 treatment compounds (vehicle, ET-1, ET-3, and secretin) with 1-d intervals between successive treatments. The treatment compounds were injected intravenously via a catheter inserted into the external jugular vein of each steer. Blood was sampled from the indwelling catheter at -30, -15, 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 150, and 180 min. Plasma ghrelin and GH responses to the treatment compounds were measured by a double-antibody radioimmunoassay system. Data were analyzed by using a MIXED procedure of SAS, version 9.1. Plasma acyl ghrelin, total ghrelin, and GH concentrations were increased by both ET-1 and ET-3 injection (ET-1 injection: 311 ± 15 pg/mL vs 245 ± 15 pg/mL, 2.4 ± 0.2 ng/mL vs 1.61 ± 0.05 ng/mL, 4.73 ± 0.92 ng/mL vs 1.17 ± 0.09 ng/mL for acyl ghrelin, total ghrelin, and GH, respectively; ET-3 injection: 337 ± 27 pg/mL vs 245 ± 15 pg/mL, 2.6 ± 0.1 ng/mL vs 1.61 ± 0.05 ng/mL, 5.56 ± 0.97 ng/mL vs 1.17 ± 0.09 ng/mL for acyl ghrelin, total ghrelin, and GH, respectively; P < 0.01). Ghrelin and GH concentrations were not changed by secretin injection throughout the experimental periods. These results indicate that ET-1 and ET-3 stimulate ghrelin and GH secretion in cattle and demonstrate for the first time that endogenous ghrelin released in response to endothelin injection stimulates GH secretion in vivo in cattle.     

The(13)C-octanoic acid breath test for detection of effects of meal composition on the rate of solid-phase gastric emptying in ponies

The aim of this study was to apply the(13)C-octanoic acid breath test for detection of alterations in the rate of solid-phase gastric emptying, induced by changes in test meal composition, in ponies. After a 14 hour fast the ponies (n = 4) ingested a test meal with 0, 35 or 70 ml soya oil, and labelled with 250 mg(13)C-octanoic acid. Each pony was given each of the three test meals on three separate occasions, in a randomised order. Exhaled breath samples were collected for 12 hours after ingestion of the test meal. Breath samples were analysed by continuous flow isotope ratio mass spectrometry. Three indices of breath(13)C-enrichment were computed, half-dose recovery time (t 1/2), gastric emptying coefficient (GEC) and time to peak breath(13)C-excretion t(max). The(13)C-octanoic acid breath test was a reliable means of assessing the significantly decreased rate of gastric emptying in the pony, associated with addition of soya oil to the test meal.     

Naproxen in the horse: Pharmacokinetics and side effects in the elderly

It is well-known that old animals show physiologic and/or pathologic variation that could modify the pharmacokinetics of drugs and the related pharmacodynamic response. In order to define the most appropriate therapeutic protocol in old horses, pharmacokinetic profile and safety of naproxen were investigated in horses aged over 18 years after oral administration for 5 days at the dose of 10 mg/kg b.w./day. After the first administration, the maximum concentration (C_max 44.21 ± 9.21 μg/mL) was reached at 2.5 ± 0.58 h post-treatment, the harmonic mean terminal half-life was 6.96 ± 1.73 h, AUC_0–24h was 459.71 ± 69.95 h μg/mL, MRT was 7.44 ± 0.74 h and protein binding was 98.47 ± 2.72%. No drug accumulation occurred with repeated administrations. No clinical and laboratory changes were detected after administration of naproxen. Gastric endoscopies performed after the treatment did not show pathological changes of the gastric mucosa.     

Effect of rare earth elements (REE) supplementation to diets on the carry-over into different organs and tissues of fattening bulls

A dose response study was carried out to assess the influence of different levels of REE supplementation on the REE transfer into different organs and tissues of fattening bulls. For this purpose, 48 male German Holstein calves with an average initial live weight of 119 ± 13 kg were divided into four treatment groups (n = 12): one control group and three REE-treated groups fed a supplement of 100, 200 and 300 mg REE-citrate/kg dry matter (DM) containing mainly cerium (57.9%), lanthanum (34.0%) and praseodymium (6.5%). The feeding trial was divided into a growing period (8 ± 3 weeks) and a fattening period (39 ± 4 weeks). The growing diet consisted of concentrate, grass silage and grass hay, and the fattening diet consisted of concentrate and maize silage. After slaughtering of the bulls (556 ± 4 kg mean live weight), the concentrations of REE were measured in the liver, kidneys, Musculus longissimus and rib bone by inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of REE (lanthanum (La), cerium (Ce) and praseodymium (Pr)) in the liver, kidneys and rib bone showed a significant linear increase with increasing dietary REE-citrate supplementation, while the REE concentration in muscle tissue remained unaffected. The highest REE concentration was measured in the liver followed by the kidneys and rib bone. In the liver, the concentration amounted to 22-482 μg/kg DM for La, 37-719 μg/kg DM for Ce and 4-73 μg/kg DM for Pr. The muscle tissue, playing an important role to evaluate food safety, showed the lowest La, Ce and Pr concentrations with 3-5 μg/kg DM, 5-7 μg/kg DM and 0.5-0.7 μg/kg DM, respectively. The results demonstrate that the health risk to humans consuming edible tissues of REE supplemented animals is very low.     

Expression of Ki-67, PCNA,and p27kip1 in canine pituitary corticotroph adenomas

Pituitary-dependent hypercortisolism (PDH), which is caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas, is a common endocrinopathy in dogs. Dogs with non-enlarged pituitaries harboring a microadenoma have a better prognosis than those with enlarged pituitaries. The aim of this study was to investigate the expression of the proliferation markers Ki-67 and proliferating cell nuclear antigen (PCNA) and the cell-cycle inhibitor p27kip1 in corticotroph adenomas in enlarged and non-enlarged pituitaries. The expression of Ki-67, PCNA, and p27kip1 was analyzed by immunohistochemical staining of 17 pituitary adenoma samples harvested during pituitary surgery in dogs with PDH. The labeling index was calculated by counting the number of immunopositive cells per 1,000 cells. The mean (± standard deviation) labeling index for Ki-67 was 8.4% ± 14.2% for the group with enlarged pituitaries, and 8.8% ± 5.5% for the group with non-enlarged pituitaries; that for PCNA was 35.5% ± 12.2% and 37.0% ± 15.5%; and that for p27kip1 was 29.3% ± 22.6% and 42.5% ± 27.9%, respectively. No significant differences in Ki-67, PCNA, and p27kip1 labeling indices were found between enlarged and non-enlarged pituitaries. However, a trend toward significance was observed when comparing the expression of p27kip1 in enlarged pituitaries versus normal pituitary tissue. It is concluded that Ki-67 and PCNA are not useful as proliferative markers for studying the pathobiology of pituitary corticotroph adenomas in dogs.     

A comparison of the effects of hydromorphone HCl and a novel extended release hydromorphone on arterial blood gas values in conscious healthy dogs

The purpose of this study was to evaluate arterial blood gases in dogs that were given hydromorphone or extended release liposome-encapsulated hydromorphone (LEH). Dogs were randomly administered LEH, n = 6, (2.0 mg kg⁻¹), hydromorphone, n = 6, (0.2 mg kg⁻¹) or a placebo of blank liposomes, n = 3, subcutaneously on separate occasions. Arterial blood samples were drawn at serial time points over a 6-h time period for blood gas analysis. There was no change from baseline values in P_aCO₂, P_aO₂, (HCO₃-), pH, and SBEc in the dogs that received the placebo. Administration of hydromorphone resulted in significant increases in P_aCO₂ (maximum (mean + SD] 44.4 + 1.1 mm of Hg) and significant decreases in P_aO₂ (minimum (mean + SD) 82.4 + 4.7 mm of Hg) and pH (minimum (mean + SD) 7.31 + 0.01) compared with baseline. Administration of LEH resulted in significant increases in P_aCO₂ (maximum (mean + SD) 44.6 + 0.9 mm of Hg) and significant decreases in P_aO₂ (minimum (mean + SD) 84.8 + 2.6 mm of Hg) and pH (minimum (mean + SD) 7.34 + 0.02) compared with baseline. There was no significant difference between these two groups at any time point. The changes observed in P_aCO₂, P_aO₂, and pH, however, were within clinically acceptable limits for healthy dogs. LEH was determined to cause moderate changes in arterial blood gas values similar to those caused by hydromorphone.     

Cytotoxicity of Senecio in macrophages is mediated via its induction of oxidative stress

In Arunachal Pradesh and other sub-Himalayan areas of India, accidental consumption of Senecio plants by yaks is often fatal as the plant contains toxic alkaloids like Seneciophylline. The present investigation was undertaken to demonstrate the pro-oxidant effects of an ethanolic extract of Seneciochrysanthemoides (S-EtOH). S-EtOH impaired viability in macrophages, the IC₅₀ being 13.8 ± 1.11 μg/mL. The effect of S-EtOH (1 μg/mL) on generation of reactive oxygen species (ROS) in macrophages was measured by flow cytometry using 2′,7′-dichlorofluorescein diacetate (H₂DCFDA) where it caused a significant increase in the mean fluorescence channel (MFC) from 8.55 ± 0.03 to 47.32 ± 2.25 (p < 0.001). S-EtOH also effected a 3.8-fold increase in extracellular nitric oxide (NO) generation from 4.90 ± 0.72 μM to 18.79 ± 0.32 μM (p < 0.001), a 2.2-fold increase in intracellular NO production, the MFC increasing from 14.95 ± 0.48 to 33.34 ± 1.66 (p < 0.001), and concomitantly depleted non protein thiols as analyzed by flow cytometry using mercury orange, with a reduction in MFC from 632.5 ± 49.44 to 407.4 ± 12.61 (p < 0.01). Additionally, S-EtOH (14 μg/mL, 24 h) caused apoptosis as evident by increased Annexin V binding and terminal deoxynucleotidyl transferase mediated dUTP DNA nick end labeling. Taken together, the cytotoxicity of S-EtOH can be partly attributed to its capacity to inflict oxidative damage via generation of both reactive oxygen and nitrogen species culminating in apoptosis.     

Effects of a long distance transport and subsequent recovery in recently weaned crossbred beef calves in Southern Chile

In Chile, prolonged transport of cattle is an important issue due to geographical conditions. This study describes the variation of body weight and some blood constituents related to stress response during one long distance transport (63 h) of recently weaned calves for fattening in the Chilean Patagonia. Results concerning blood variables related to stress showed that the whole process of rounding up, weaning and transport was stressful for the calves and that animal welfare was impaired. Cortisol values were significantly lower after unloading (1.0±0.4 μg/dl), as compared to before loading (1.5±0.4 μg/dl). The significant body weight loss from before loading (240±26.9 kg) to after unloading (210±24.2 kg), and the long recovery time, adds economic losses to the producers at destiny. As transport period cannot be shortened due to the typical Chilean geography in the Patagonian region and the scarcity of proper routes, it is recommended that conditions of transported calves should be improved by using specialized livestock vehicles that can provide more comfort, as well as access to water and food during the journey.