Omega-3 Fatty Acid Supplementation Affects Selected Phospholipids in Peripheral White Blood Cells and in Plasma of Full-Sized and Miniature Mares

Dietary omega-3 fatty acids (n-3 PUFA), notably eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), impart health benefits in humans and animals. In horses, dietary n-3 PUFAs elevate EPA and DHA and may promote anti-inflammatory effects. No reports document effects of dietary n-3 PUFA on fatty acyl components of circulating and cellular phospholipids in horses nor whether responses to dietary n-3 PUFA are similar among horse breeds. Ten Quarter Horse and 10 American Miniature Horse mares were assigned to n-3 PUFA (64.4 mg· kg body weight [BW]⁻¹·d⁻¹) or control diet for 56 days. Blood was sampled at 0, 28, and 56 days. Apparent phospholipid molecular species from several classes (phosphatidylcholine [PC]; “ether-linked” phosphatidylcholine [i.e., alk(en)yl, acyl glycerophosphocholine] [ePC]; phosphatidylethanolamine [PE]; phosphatidylinositol [PI]; and phosphatidylserine [PS]) were determined in plasma and peripheral blood mononuclear cells (PBMC) by mass spectrometry. Statistical analysis showed that six phospholipid species had diet × day interactions (P < .05) for both plasma and PBMC. Further evaluation of these species demonstrated that the mole percentage of PC(38:6), PC(40:7), PC(42:10), PE(38:5), PE(40:6), and PE(40:7) (where x:y represents total acyl carbon:total carbon-carbon double bonds) in both plasma and PBMC phospholipids was elevated in horses fed n-3 PUFA (P < .001 for all). Analysis of the acyl product ions revealed that these contained an acyl chain of mass consistent with an n-3 PUFA. Thus, supplementation increased n-3 PUFA in selected plasma and PBMC phospholipids. The absence of breed effects suggests that miniature and full-size horses responded similarly to dietary treatment.     

Using the indicator amino acid oxidation technique to study threonine requirements in horses receiving a predominantly forage diet

Threonine has been reported to be the second limiting amino acid in typical equine diets, but its actual requirement has not been determined in horses. To evaluate amino acid metabolism and requirements, the indicator amino acid oxidation (IAAO) method has been successfully used in other species. The objective of this research was to estimate threonine requirements in mature horses fed timothy hay and concentrate in 4:1 ratio using the IAAO method. Six Thoroughbred mares (579.9 ± 46.7 kg) received each of 6 levels of threonine intake, 41, 51, 61, 70, 80 and 89 mg/kg BW/day, in a randomly determined order. Each study period was 7‐day long, and on day 6, blood samples were collected before and 90 min after feeding to measure amino acid concentrations using HPLC. On day 7, horses underwent IAAO procedures, which included a 2‐hr primed, constant intravenous infusion of [¹³C]sodium bicarbonate to measure total CO₂ production and a 4‐hr primed, constant oral administration of [1‐¹³C]phenylalanine to estimate phenylalanine oxidation to CO₂. Blood and breath samples were collected to measure blood [¹³C]phenylalanine, using GC‐MS analysis and breath ¹³CO₂ enrichment, using an infrared isotope analyser. Increasing threonine intake levels did not affect plasma phenylalanine oxidation by the ANOVA test (p > 0.05) but resulted in a linear decrease in phenylalanine oxidation (p = 0.04) without a breakpoint by the orthogonal linear contrast. This study is the first attempt to evaluate threonine requirements in horses by the IAAO method; however, threonine requirements are still unknown in mature horses at this time.     

Validation of the Lactate Plus Lactate Meter in the Horse and Its Use in a Conditioning Program

The equine industry has a need for a convenient, rapid, and reliable method of measuring blood lactate concentrations ([LA]). We hypothesized that the handheld Lactate Plus lactate meter (LPlus), developed and tested for use in humans, would provide dependable results when used in horses undergoing an exercise conditioning program and that horse's fitness would improve following individualized conditioning based on each horse's velocity at which [LA] = 4 mmol/L (V_LA4) was reached. Five adult horses underwent a 4-week training program that consisted of 3 exercise bouts/wk. Horses were subjected to an incremental step standardized exercise test (SET) before starting (SET-1) and after the completion of the program (SET-2). Blood samples were collected before each increase in speed until [LA] reached ≥4 mmol/L, and then the SET was terminated. The [LA] sample range in our study was 0–8 mmol/L. Blood was analyzed at the time of collection using a calibrated LPlus, and plasma was collected for [LA] determination using the lactate dehydrogenase–based enzymatic colorimetric method. Although the LPlus tended to significantly underestimate [LA] by 0.39 mmol/L (P < .001), the LPlus proved to be a dependable device for use in horses based on good correlation with the biochemical analysis (r = 0.978) and Bland–Altman limits of agreement and 95% confidence intervals. All horses showed an increase in V_LA4 from SET-1 to SET-2, consistent with improved fitness following our 3 exercise bout/wk training protocol. The LPlus can reliably be used in horses to determine [LA] ranging from 0–8 mmol/L. When determining serial [LA], analytical techniques should not be used interchangeably.     

Comparison of T-cell subpopulations in cats naturally infected with feline leukaemia virus or feline immunodeficiency virus

T-cell subsets were studied by flow cytometry in 58 feline leukaemia virus (FeLV)-positive cats with naturally acquired FeLV infection to determine whether the changes in CD4⁺ or CD8⁺ T cell populations differed from those observed in 55 feline immunodeficiency virus (FIV)-positive cats with naturally acquired FIV infection. The sole criterion for inclusion into the study was seropositivity. Mean (SD) CD4⁺ T cell values of FeLV positive cats were decreased to 31·1 (8·0) per cent and their CD8⁺ T cell values were increased to 22·8 (6·3) per cent in comparison with uninfected control cats (37·9 [9·5] per cent CD4⁺; 15·2 [6·3] per cent CD8⁺). The CD4⁺/CD8⁺ ratio was reduced to 1·5 (0·7), compared with 3·0 (1·5) in 39 FeLv- and FIV-negative control cats. Differences from control values were significant, but there was no significant difference between CD4⁺ and CD8⁺ lymphocytes of FeLV- versus FIV-infected cats. These findings indicate that FeLv and FIV have similar effects on T lymphocyte subsets. Both retrovirus infections can induce immunodeficiency, both viruses infect a broad range of lymphohaemopoietic cells, despite having different primary target cells, and can induce the killing of lymphocytic cells in vitro. It is concluded that a decreased CD4⁺/CD8⁺ ratio is not restricted to FIV infections but may also occur in FeLv infection.     

Venous Blood Acid-Base Status in Show Jumper Horses Subjected to Different Physical Exercises

The aim of this study was to assess whether acid-base profile exhibits changes in regularly trained show jumping horses undergoing increasing exercise workloads. Seven female Italian saddle horses were subjected to three different physical exercise trials of increasing workload identified as three exercise phases (EPs). During EP_I horses were subjected to a standardized exercise test consisting of 15 minutes of treadmill, during EP_II horses were subjected to a show jumping test (height, 0.9–1.1 m; course length, 300 m), during EP_III horses underwent two jumping sessions carried out over two consecutive days. Blood samples were collected at rest (T_PRE), after exercise (T_POST), and 30 minutes after the end of exercise (T_POST30). The values of pH, partial pressure of carbon dioxide (Pco₂), partial pressure of oxygen (Po₂), bicarbonate level (HCO₃⁻), hemoglobin (Hb), and hematocrit (Hct) were measured. A significant effect of exercise workload and time (P < .001) on Po₂, Pco₂, HCO₃⁻, Hb, and Hct values was found. The variation in the studied parameters resulted mostly reversible within T_POST30 in horses when subjected to EP_I and EP_II, whereas Po₂, Hb, and Hct remained higher at T_POST30 than T_PRE in horses when subjected to the second day of jumping section (EP_III) indicating a failure to recover. The results suggest that jumping sessions carried out over two consecutive days represent extra workload for horses, and this should be taken into account by veterinarian to prevent acid-base imbalance and for the maintenance of health and performance in equine athletes.     

Rapid calcitonin response to experimental hypercalcemia in healthy horses

Calcium has important physiological functions, and disorders of calcium homeostasis are frequent in horses. We have made important progress understanding equine calcium homeostasis; however, limited information on equine calcitonin (CT) is available, in part because of the lack of validated CT assays. To determine the CT response to high ionized calcium (Ca²⁺) concentrations in healthy horses, we induced hypercalcemia in 10 healthy horses using a calcium gluconate 23% solution (5 mg/kg; 120 mL/500 kg horse) infused over 4 min. Four horses were infused with 120 mL of 0.9% NaCl and used as controls. We validated a human-specific CT radioimmunoassay for use in horses. Serum Ca²⁺ concentrations increased from 6.2 ± 0.3 mg/dL to 9.9 ± 0.5 mg/dL (4 min; P < 0.01). Serum CT increased from 16.7 ± 8.0 pg/mL to 87.1 ± 55.8 pg/mL at 2 min, and 102.5 ± 51.1 pg/mL at 4 min (P < 0.01). Serum CT returned to baseline by 20 min, whereas serum Ca²⁺ returned to baseline by 40 min. Of interest, CT concentrations returned to baseline despite hypercalcemia, suggesting thyroid gland C-cell CT depletion. Resting CT values higher than 40 pg/mL were considered abnormally elevated. No significant changes in serum Ca²⁺ or CT concentrations were found in control horses. The coefficients of variation for the CT radioimmunoassay were lower than 11.9%. We conclude that the equine thyroid gland C-cell responds quickly to changes in extracellular Ca²⁺ concentrations by secreting large quantities of CT into the systemic circulation, indicating that CT is important in equine calcium homeostasis. The human CT radioimmunoassay can be used to measure changes in equine CT.     

To jump or not to jump? Strategies employed by leisure and sport horses

Show jumping is one of the most popular equestrian disciplines although strategic jumping per se is seldom used by free-living horses when negotiating obstacles that they might otherwise avoid. To establish if horses are naturally motivated to jump, we examined horses in a free-choice situation when negotiating various obstacles under test conditions. Eighteen leisure horses (LHs) and 16 sport horses (SHs) participated in a number of 2-choice tests. First, horses were presented with 2 optional routes during a “free-choice test” to reach a food stimulus. The choices were a shorter route (over an obstacle) or a longer route (around the obstacle). During 8 consecutive trials, the horses encountered an increase in obstacle height on every second trial as follows: 0, 20, 35, and 50 cm. In the “ridden test” after an initial conditioning period, the horses were tested with a Y-maze formation during 3 consecutive trials, where one element of the maze contained an obstacle arm (OA). The horses walked or trotted over the obstacle most frequently (59.9%) and jumped the obstacle in only 10.7% of the cases. For both the LH and SH groups, the horses' motivation to traverse the obstacle decreased as the obstacle height increased and only 44.1% of horses actually negotiated the 50-cm obstacle as compared with the 20-cm obstacle (85.3%). The LH group preferred to go around the obstacle significantly more often than the SH group (24 trials, 16.7% vs. 9 trials, 7.0%, for SH and LH, respectively; χ² = 6.81, N = 33, P = 0.0090). The LH group used a jumping strategy to clear the obstacle far less frequently (6 trials, 4.2%) than the SH group (23 trials, 18.0%; χ² = 9.96, N = 29, P = 0.0023). In the Y-maze trials, the LH group exhibited preference (40 per 54 trials, 74.1%; χ² = 12.5, P < 0.0001), and the SH group failed to exhibit any preference (20 per 48 trials; χ² = 1.33, P = 0.3123). There was no evidence of any correlation between the motivation to clear the obstacle and total number of OA choices in either the LH group (r_s = 0.13, P = 0.9594) or the SH group (r_s = ?0.25, P = 0.3492). The findings from the present study indicate that SHs are motivated and willing to jump obstacles more often than are LHs under similar conditions. However, the apparent reluctance of the horses overall to continue jumping as the obstacle height increases suggests that, in general, many horses could easily encounter excessive demands (overfacing) in sport. This issue should be carefully monitored in terms of equine training, competition, and welfare.     

Comparison of Chondrogenic Potential in Equine Mesenchymal Stromal Cells Derived from Adipose Tissue and Bone Marrow

Objective— To compare the chondrogenic potential of adult equine mesenchymal stem cells derived from bone marrow (MSCs) or adipose tissue (ASCs). Study Design— In vitro experimental study. Animals— Adult Thoroughbred horses (n=11). Methods— BM (5 horses; mean [±SD] age, 4±1.4 years) or adipose tissue (6 horses; mean age, 3.5±1.1 years) samples were obtained. Cryopreserved MSCs and ASCs were used for pellet cultures in stromal medium (C) or induced into chondrogenesis±transforming growth factor‐3 (TGFβ₃) and bone morphogenic factor‐6 (BMP‐6). Pellets harvested after 3, 7, 14, and 21 days were examined for cross‐sectional size and tissue composition (hematoxylin and eosin), glycosaminoglycan (GAG) staining (Alcian blue), collagen type II immunohistochemistry, and by transmission electron microscopy. Pellet GAG and total DNA content were measured using dimethylmethylene blue and Hoechst DNA assays. Results— Collagen type II synthesis was predominantly observed in MSC pellets from Day 7 onward. Unlike ASC cultures, MSC pellets had hyaline‐like matrix by Day 14. GAG deposition occurred earlier in MSC cultures compared with ASC cultures and growth factors enhanced both MSC GAG concentrations (P<.0001) and MSC pellet size (P<.004) after 2 weeks in culture. Conclusion— Equine MSCs have superior chondrogenic potential compared with ASCs and the equine ASC growth factor response suggests possible differences compared with other species. Clinical Relevance— Elucidation of equine ASC and MSC receptor profiles will enhance the use of these cells in regenerative cartilage repair.     

Assessment of Insulin and Glucose Dynamics by Using an Oral Sugar Test in Horses

Straightforward testing procedures are needed to facilitate the diagnosis of insulin dysregulation in horses because hyperinsulinemia and insulin resistance are associated with laminitis. Results of an oral sugar test (OST) were compared with those of the intravenous glucose tolerance test (IVGTT). We hypothesized that OST and IVGTT area under the curve values for glucose (AUCg) and insulin (AUCi) would be closely correlated, as defined by a correlation coefficient value ≥0.90. Both tests were performed in 10 horses meeting the criteria for equine metabolic syndrome (EMS) and 8 Quarter horse crossbred mares from a university teaching herd (control group). The OST was also performed in 21 Quarter horse crossbred mares from the same herd, and test repeatability was evaluated in 8 of these horses. All testing was performed under fasting conditions. Median AUCg and AUCi values were 1.3- and 9.0-fold higher, respectively, for the IVGTT and 1.3- and 6.8-fold higher, respectively, for the OST in the EMS group than those in the control group. AUCg (Spearman correlation coefficient [r_s] = 0.58; P = .012) and AUCi (r_s = 0.90; P < .001) values for the two tests were positively correlated. Mean ± SD coefficients of variation for repeated tests in 8 mares were 6.4% ± 3.1% and 45.1% ± 36.2% for AUCg and AUCi, respectively. We conclude that OST and IVGTT insulin results are closely correlated, so the OST warrants further consideration as a field test for insulin dysregulation in horses.     

Respiratory Characteristics of the Blood of Labeo Umbratus (SMITH) and Labeo Capensis (Smith)

Various respiratory characteristics of mudfish blood were investigated. Oxygen and carbon dioxide contents of mixed venous blood were 1,17±0,53 and 11,35±1,65 vol. % respectively. Blood oxygen dissociation curves showed P₅₀ values of 11,84±3,1; 13,77±2,0 and 18,05±4,7 mm Hg at CO₂, concentrations of 0-1%, 4-5% and 9-10%. A marked Bohr effect of —0,59 was observed and the Haldane effect was found to be relatively low. No differences could be observed between the characteristics of L. umbratus and L. capensis blood.     

Segment-dependent Expression of Muscarinic Acetylcholine Receptors and G-protein Coupling in the Equine Respiratory Tract

Muscarinic receptors are considered to be of comparable clinical importance in chronic obstructive pulmonary disease (COPD) in equines and in humans. At present, data are scarce on the expression and distribution of probable subtypes of these receptors and their signalling pathways in airway segments, including lung parenchyma and bronchial and tracheal epithelium with the underlying smooth muscle in horses. Specific [N-methyl-³H]scopolamine chloride ([³H]NMS) binding to all three tissues was saturable and of high affinity, with K _D values ranging between 1.6±0.7 and 1.9±0.3 nmol/L. [³H]NMS binding identified a higher density of total muscarinic receptors (fmol/mg protein) in the trachea (720±59 nmol/L) than in bronchi (438±48 nmol/L) or lung (22 ± 3 nmol/L). Competitive binding studies using [³H]NMS and the unlabelled subtype-selective antagonists pirenzepine and telenzepine (M₁), methoctramine and himbacine (M₂), 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) (M₃), tropicamide (M₄) and mamba toxin (MT-3) (M₄) indicated the presence of at least three muscarinic receptor subtypes in peripheral lung tissue (50:40:24–28%: M₂>M₃>M₁), whereas in bronchus and trachea M₂ subtypes (87–90%) predominated over M₃ (14–22%), and M₁ subtypes were lacking. No differences were found between tissues in high-affinity binding sites for carbachol in the absence (31–36%) or presence of guanosine 5^′-triphosphate (GTP) (∼100%). Western blotting for G-protein α-subunits showed a much more robust expression of G_αi1/2 in the trachea (with highest receptor density) than in the lung or bronchi, whereas G_αs-protein was dominantly expressed in bronchus. Concomitantly, carbachol inhibited isoproterenol- and GTP-stimulated adenylyl cyclase activity with increasing muscarinic receptor expression (trachea > bronchi > lung). We conclude that the expression and signalling pathways of muscarinic receptors in the equine respiratory tract are segment-dependent. These receptors might contribute to the pathogenesis of COPD in the horse and could provide potential drug targets for the therapeutic use of anticholinergics in this species.     

Arterial blood gases and acid-base balance in geriatric dogs

To compare arterial blood gas pressures and acid-base balance in geriatric and young adult dogs, 23 clinically healthy aged dogs (>10 years old) and 16 young adult dogs (two to four years old) were studied. Blood gases (PaO₂ and PaCO₂), pH, Na, K, Ca and Cl were measured in arterial blood samples using selective electrodes. Haemoglobin was quantified with a co-oximeter. Total proteins and phosphorus were measured by spectrophotometry in plasma. The alveolar to arterial PO₂ gradient (P(A-a)O₂), bicarbonate, anion gap and the base excess of blood were calculated. Quantitative analysis of acid-base balance was carried out by calculating unidentified anions. Old dogs had significantly higher P(A-a)O₂ than young dogs (2·5±0·3 versus 1·4±0·3 KPa). Although the differences were not significant, aged dogs also had a lower PaO₂. No differences were detected in PaCO₂, pH, Na, K, Ca, Cl, haemoglobin, phosphorus, bicarbonate and base excess of blood. Plasma proteins were higher in old dogs than in young dogs (7·1±0·2 versus 6·5±0·2 g dl⁻¹). Anion gap was increased in aged dogs; however, no changes were found in unidentified anions. In conclusion, an increase in P(A-a)O₂ has been identified in a group of geriatric dogs. No major changes have been found in the acid-base balance of aged dogs.     

Thromboelastography in healthy horses and horses with inflammatory gastrointestinal disorders and suspected coagulopathies

Objectives – To evaluate the use of citrated recalcified (nonactivated) thromboelastography (TEG) in healthy horses and horses with colitis and suspected coagulopathies. Design – Prospective, observational study conducted between October 2007 and June 2009. Setting – Veterinary Teaching Hospital. Animals – Forty‐five healthy adult horses and 12 sick adult horses with colitis and prolonged prothrombin time (PT) or activated partial thromboplastin time (aPTT). Interventions – None. Measurements and Main Results – Whole blood was collected on admission. Coagulation profile (PT, aPTT, platelet count, and fibrinogen concentration) and citrated recalcified whole blood TEG analysis (R‐time [R], K‐time [K], angle [α], maximum amplitude [MA], G value [G], lysis at 60 min [LY60]) were evaluated. Mean values (SD) for TEG parameters in healthy horses were: R=10.4 (3.1) minutes; K=3.5 (1.2) minutes; α=46.3 (11.0)°; MA=55.6 (5.1) mm; G=6,429 (1,341) dyn/cm², and LY60=5.1 (2.4)%. Mean coefficients of variation for intra‐assay/interindividual variability in healthy horses were: R=4.7%/30.7%, K=4.8%/35.3%, α=4.4%/23.8%, MA=1.4%/9.3%, G=3.4%/20.8%, and LY60=13.1%/47.7%, respectively. Horses with colitis and prolonged PT and/or aPTT had longer mean values for R (P<0.001) and K (P<0.001), narrower mean α (P<0.001), decreased mean MA (P=0.001), and smaller mean G (P=0.02); changes consistent with hypocoagulability. Conclusions – Citrated recalcified (nonactivated) TEG demonstrated changes consistent with hypocoagulability in horses with colitis that had preidentified coagulation abnormalities. This technique has high interindividual variability and low intra‐assay variability. TEG may be useful for detecting hypocoagulable states in horses with colitis and suspected coagulopathies.     

Studies on Blood and Serum Types of the Icelandic Horses

By means of isoimmunizations and heteroimmunizations 10 equine blood typing reagents were isolated. The specific antibodies were complete agglutinins, which were used in the direct agglutination test in saline medium. The reagents were designated A₂, C, D, E, G, H, I, K, Da₁, and Da₂ reagent. Da₁ and Da₂ are preliminary designations.The data obtained from blood typing of a family material and a population material of Icelandic horses showed that the occurrence of each blood type factor is controlled by a single, dominant gene. The family data tended to show that the blood factors under investigation belonged to 8 blood type systems. The A system contained the antigens A₂ and Da₂. These antigens are related to each other through a linear subgroup relationship. The D system had the factors D and J. The G, E, G, I, K, and Da₁ systems are one-factor, two-allele blood type systems. The H factor was not observed in Icelandic horses. In connection with the establishment of the 8 blood type systems it must be emphasized that the problem of allelism or nonallelism of 2 genes can only be solved by means of relevant family data. Because of the rare occurrence of some of the blood factors in the Icelandic horse such data were in some cases not available. Thus some conclusions were based on results from two-by-two contingency tables with the use of population data. This was used particularly for the D and G systems, and additional family data are necessary for a definite establishment of these systems.Exceptions to the genetic theory, apparently caused by erroneous registration, were presented.Finally, estimates were given of gene frequencies of the causative genes among Icelandic horses.Starch gel electrophoresis of sera from Icelandic horses revealed the existence of 21 transferrin phenotypes. The data obtained supported the theory advanced, that transferrin polymorphism in horses is controlled by 6 autosomal codominant alleles: Tf^D, Tf^F, Tf^H, Tf^M, Tf^O, and Tf^H.925 randomly selected Icelandic horses were typed for serum transferrin and the gene frequencies were estimated.Starch gel electrophoresis of about 100 horse serum samples did hot reveal individual variation of the equine haptoglobin and ceruloplasmin. Studies on approximately 300 sera showed an identical serum amylase pattern.     

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.     

Culture and characterisation of equine peripheral blood mesenchymal stromal cells

Although the use of mesenchymal stromal cells (MSCs) for the treatment of orthopaedic injuries in horses has been reported, no official guidelines exist that classify a particular cell as an equine MSC. Given the limited characterisation of peripheral blood (PB)-derived equine MSCs in particular, this study aimed to provide more detailed information in relation to this cell type. Mesenchymal stromal cells were isolated from equine PB samples and colony forming unit (CFU) assays as well as population doubling times (PDTs) (from P₀ to P₁₀) were performed.Two types of colonies, ‘fingerprint’ and dispersed, could be observed based on macroscopic and microscopic features. Moreover, after an initial lag phase (as indicated by a negative PDT at P₀ to P₁) the MSCs divided rapidly as indicated by a positive PDT at all further passages. Immunophenotyping was carried out with trypsin- as well as with accutase-detached MSC to evaluate potential trypsin-sensitive epitope destruction on particular antigens. Isolated MSC were positive for CD29, CD44, CD90 and CD105, and negative for CD45, CD79α, MHC II and a monocyte/macrophage marker, irrespective of the cell detaching agent used. Trilineage differentiation of the MSCs towards osteoblasts, chondroblasts and adipocytes was confirmed using a range of histochemical stains.     

The effect of storage on the P50 of feline blood

Objective: To determine the effect of storage on the P₅₀ of feline hemoglobin. Design: Prospective, in vitro, laboratory study. Subjects: Venous blood from 4 clinically healthy cats. Measurements: Blood was collected into CPDA‐1 anticoagulant/preservative and maintained at 4°C for 5 weeks. Measurements were made on Days 0, 2, 4, 7, 14, 21, 28, and 35. The blood samples were equilibrated in a tonometer to gas mixtures containing 2.5%, 4%, 5%, or 8% oxygen, with 5% carbon dioxide balance nitrogen; pH was adjusted to 7.4. Chloride, partial pressure of oxygen, and hemoglobin saturation were measured; P₅₀ was calculated. Results: Chloride decreased from 124.3±2.1 to 88.5±1.9 mEq/L immediately after dilution with CPDA‐1, and did not change for the 5 weeks thereafter. The P₅₀ decreased from an average of 35.0±1.2 to between 31 and 32 mmHg after 7 days, and did not change further for 4 weeks thereafter. Conclusions: The decrease in P₅₀ of feline hemoglobin was minor compared with that of blood from species in which 2,3‐diphosphoglycerate (2,3‐DPG) is a major modifier of hemoglobin affinity for oxygen. The decrease in P₅₀ in the present study was attributed to an initial decrease in chloride and a subsequent loss of modest quantities of red cell 2,3‐DPG.     

Laboratory Studies on the Transmission of Western Equine Encephalitis Virus by Saskatchewan Mosquitoes I. Culex tarsalis

A Saskatchewan strain of the mosquito Culex tarsalis, transmitted a local strain of western equine encephalitis virus from chick to chick, between four and 44 days after an infective blood meal. At incubation temperatures of 69 and 75°F, 120 transmissions occurred out of a possible 141, and all but seven of these were by single infected mosquitoes. At 75°F virus titers in individual mosquitoes were more uniform and transmission was more efficient, than at 69°F, although infection rates were similar at both temperatures. The minimum concentration of virus required to infect 50% of C.tarsalis was 10^2.5 intracerebral three-week old mouse LD₅₀ per 0.03 ml of donor blood. These findings provide direct evidence that C. tarsalis of Saskatchewan is a highly efficient vector of western equine encephalitis virus.     

Adverse effects of polymyxin B administration to healthy horses

BackgroundPolymyxin B (PolyB) is used to treat endotoxemia in horses; neurologic and nephrogenic adverse effects occur in humans.ObjectivesTo describe PolyB adverse effects in horses.AnimalsFive healthy horses (ataxia 0/5), 1 horse with cervical osteoarthritis (ataxia 1/5).MethodsProspective blinded randomized cross‐over trial; 3‐weeks wash out. Horses received PolyB (PolyB 6000 IU/kg IV, 7 doses q12h, n = 6) and PolyB/gentamicin (PolyB 6000 IU/kg IV, q12h 7 doses; gentamicin 10 mg/kg IV q24h 4 doses n = 4, or q12‐24 h 5 doses because of an additional erroneous dose, n = 2). Daily neurological examinations were video recorded, and ataxia graded by 3 observers. Urine status, urinary GGT/creatinine ratio, plasma creatinine, and urea were assessed every other day, EMG daily. Mixed model analysis was used to evaluate factors associated with ataxia grade and [PolyB].ResultsMedian ataxia score increased from 0/5 (range 0‐2/5) to 2/5 (range 1‐3/5) during administration and declined to 0.5/5 (range 0‐2/5) after cessation. Gentamicin co‐administration (P < .01, effect size: .8), number of PolyB doses (P < .001, effect size: .6), and time since last PolyB dose (P < .001, effect size: .5) had a significant effect on ataxia grades, while horse, day, [Genta], [PolyB], and [PolyB]_CSF did not. Gentamicin co‐administration and [Genta] C_peak had no effect on median [PolyB] C_peak (4.67 and 4.89 μg/ml for PolyB and PolyB/gentamicin, respectively). Urinary GGT/creatinine ratio was elevated in 3/6 horses receiving PolyB/gentamicin. The EMG remained unchanged.Conclusions and Clinical ImportancePolyB caused transient ataxia, worsening with cumulative PolyB doses and gentamicin co‐administration. Nephrotoxicity of PolyB was only evident when gentamicin was co‐administered.     

Acupuncture Needle Stimulation on Some Physiological Parameters After Road Transport and Physical Exercise in Horse

The aim of this study was to evaluate the effect of acupuncture (AG) treatment on some hematochemical parameters in five Thoroughbred horses after road transport and exercise. Horses competed in two official races. For each race, animals were transported from their stables to the racetrack. Horses transported and competed in the first race represent the control group. Two weeks later, the same horses competed in the second race. Before road transport, they were treated with AG. From animals, blood samples were collected at rest (T_PRE), after unloaded (T_POST), 30 minutes after unloaded (T_POST30), at rest in the transit stall (R_PRE), at the end of the race (R_POST), and 30 minutes after the race (R_POST30). The effect of transport, exercise, and AG was evaluated on blood lactate, glucose, red blood cell, hemoglobin, hematocrit, mean corpuscular volume, and erythrocyte osmotic fragility (EOF) values. A significant effect of transport (P < .05) and exercise (P < .01) was found on all studied parameters in both groups. A significant effect of AG on lactate, glucose, and EOF values was found in transported (P < .001) and exercised horses (P < .05). The results found in this study showed that transport and exercise are potential stressors for the athlete horse that may affect its welfare and physical performance. The data suggest that AG stimulation promoted the increase of blood glucose values and the reduction of lactate and EOF levels suggesting its role in the improvement of the physiological adaptation to stressful stimuli and of physical performance of Thoroughbred horses.