Distribution of cardiac output in anaesthetised horses

The radioactive microsphere method was used to determine the distribution of cardiac output in six anaesthetised ponies. Simultaneous measurements of cardiac output allowed calculation of the tissue perfusions (ml/min/100 g). Allowing for the fact that measurements were carried out on animals under halothane anaesthesia and which had respiratory acidosis, the results were comparable with published values for other species.     

Effect of histamine on blood flow to the adrenal glands of pigs

Blood flow to the adrenal glands was measured with radioactive microspheres labeled with⁸⁵Sr in 25–37 kg pigs following the intravenous infusion of physiological saline solution or histamine solution (2 ug/kg/min) for 60 minutes. Total blood flow averaged 2.28 ml/min/gland for control pigs and 4.38 ml/min/gland for histamine-treated pigs (P<.0005). Mean blood flow to the adrenal glands of histamine-treated pigs (3.15 ml/min/g) was 82% higher than that of control pigs (1.73 ml/min/g); the difference was highly significant (P<.0005). The result of this study showed that histamine caused an increased blood flow to the porcine adrenal glands.     

The effect of guaiphenesin on romifidine/ketamine anaesthesia in ponies

The purpose of this study was to investigate the effect of a single dose (50 mg/kg) of guaiphenesin on recumbency time, surgical conditions and the ‘quality’ of anaesthesia in ponies anaesthetised for castration. Sixteen ponies were sedated with romifidine 100 μg/kg and anaesthetised with ketamine (2.2 mg/kg). Ponies allocated to Group A received no treatment and those in Group B were given 50 mg/kg of a 15% guaiphenesin solution. Guaiphenesin was given as a rapid iv injection immediately after induction of anaesthesia. All ponies were subsequently castrated. The mean (± se) time of recumbency in Group A was 20.9 ± 1.37 min and in Group B 27.2 ± 2.1 min to (P<0.05). Subjective assessment scores for the quality of surgical conditions and anaesthesia itself were significantly greater (indicating better conditions) in ponies receiving guaiphenesin, although there was no difference between groups in the quality of recovery.     

Pharmacokinetics of intramuscularly administered pethidine in dogs and the influence of anaesthesia and surgery

The plasma concentration of pethidine was measured after it had been administered intramuscularly to fully conscious dogs, and to dogs in the postoperative period and during general anaesthesia. The absorption of the drug was erratic except in the anaesthetised animals and the plasma concentrations of the drug were also higher in this group. Correlation of plasma concentrations of the drug with its analgesic activity revealed a 'critical' concentration of pethidine of 0.4 micrograms/ml for complete analgesia; useful though not complete analgesia was achieved with concentrations above 0.2 micrograms/ml. These concentrations were maintained for 90 minutes after the administration of the drug at a dose of 2.0 mg/kg and for 120 minutes after a dose of 3.5 mg/kg.     

Comparison of cardiovascular function and quality of recovery in isoflurane‐anaesthetised horses administered a constant rate infusion of lidocaine or lidocaine and medetomidine during elective surgery

Reasons for performing study: The effects of lidocaine combined with medetomidine or lidocaine alone on cardiovascular function during anaesthesia and their effects on recovery have not been thoroughly investigated in isoflurane‐anaesthetised horses. Objectives: To determine the effects of an intraoperative i.v. constant rate infusion of lidocaine combined with medetomidine (Group 1) or lidocaine (Group 2) alone on cardiovascular function and on the quality of recovery in 12 isoflurane‐anaesthetised horses undergoing arthroscopy. Hypothesis: The combination would depress cardiovascular function but improve the quality of recovery when compared to lidocaine alone in isoflurane‐anaesthetised horses. Methods: Lidocaine (2 mg/kg bwt i.v. bolus followed by 50 µg/kg bwt/min i.v.) or lidocaine (same dose) and medetomidine (5 µg/kg bwt/h i.v.) was started 30 min after induction of anaesthesia. Lidocaine administration was discontinued 30 min before the end of surgery in both groups, whereas medetomidine administration was continued until the end of surgery. Cardiovascular function and quality of recovery were assessed. Results: Horses in Group 1 had longer recoveries, which were of better quality due to better strength and overall attitude during the recovery phase than those in Group 2. Arterial blood pressure was significantly higher in Group 1 than in Group 2 and this effect was associated with medetomidine. No significant differences in cardiac output, arterial blood gases, electrolytes and acid‐base status were detected between the 2 groups. Conclusions and potential relevance: The combination of an intraoperative constant rate infusion of lidocaine and medetomidine did not adversely affect cardiovascular function in isoflurane‐anaesthetised horses and improved the quality of recovery when compared to an intraoperative infusion of lidocaine alone.     

Hemodynamic,respiratory and sedative effects of progressively increasing doses of acepromazine in conscious dogs

ObjectiveTo evaluate the effects of progressively increasing doses of acepromazine on cardiopulmonary variables and sedation in conscious dogs.Study designProspective, experimental study.AnimalsA group of six healthy, adult, mixed-breed dogs weighing 16.5 ± 5.0 kg (mean ± standard deviation).MethodsDogs were instrumented with thermodilution and arterial catheters for evaluation of hemodynamics and arterial blood gases. On a single occasion, acepromazine was administered intravenously to each dog at 10, 15, 25 and 50 μg kg^–1 at 20 minute intervals, resulting in cumulative acepromazine doses of 10 μg kg^–1 (ACP₁₀), 25 μg kg^–1 (ACP₂₅), 50 μg kg^–1 (ACP₅₀) and 100 μg kg^–1 (ACP₁₀₀). Hemodynamic data and sedation scores were recorded before (baseline) and 20 minutes after each acepromazine dose.ResultsCompared with baseline, all acepromazine doses significantly decreased stroke index (SI), mean arterial pressure (MAP) and arterial oxygen content (CaO₂) with maximum decreases of 16%, 17% and 21%, respectively. Cardiac index (CI) decreased by up to 19% but not significantly. Decreases of 26–38% were recorded for oxygen delivery index (DO₂I), with significant differences for ACP₅₀ and ACP₁₀₀. Systemic vascular resistance index (SVRI) and heart rate did not change significantly. No significant difference was found among acepromazine doses for hemodynamic data. After ACP₁₀, mild sedation was observed in five/six dogs and moderate sedation in one/six dogs, whereas after ACP₂₅, ACP₅₀ and ACP₁₀₀, moderate sedation was observed in five/six or six/six dogs.Conclusions and clinical relevanceIn conscious dogs, acepromazine decreased MAP, SI, CaO₂ and DO₂I, but no significant dose effect was detected. SVRI was not significantly changed, suggesting that the reduction in MAP resulted from decreased CI. The ACP₂₅, ACP₅₀ and ACP₁₀₀ doses resulted in moderate sedation in most dogs; ACP₁₀ resulted in only mild sedation.     

Mitogen-induced transformation of sheep and goat peripheral blood lymphocytes in vitro: The effects of varying culture conditions and the choice of an optimum technique

Peripheral blood lymphocytes (PBL) prepared by centrifugation of heparinized sheep or goat jugular venous blood on Ficoll-Triosil were shown to incorporate methyl-[H³]-thymidine ([H³]-Tdr) in vitro in response to lymphocyte mitogens.Optimal conditions for transformation included the culture of 2.5 × 10⁵ viable cells per round bottomed culture well in 250μl medium RPMI-1640 supplemented with fetal calf serum (FCS) at 10% for goat or 15% for sheep lymphocytes. Optimum incorporation of [H³]-Tdr by sheep PBL was recorded after 3–5 days and was achieved in response to 100μg/ml phytohaemagglutinin (PHA), 20μl/ml pokeweed mitogen (PWM), 10μg/ml Concanavalin-A (Con-A) and 50μg/ml bacterial lipopolysaccharide (LPS). For goat PBL the optimum mitogen concentrations were 50μg/ml PHA, 20μl/ml PWM, 5μg/ml Con-A and 50μg/ml LPS. Optimum PHA concentrations were influenced by the level of FCS supplementation, higher concentrations of PHA being required for optimum response when the concentration of FCS was increased.While variability within preparations was small there was considerable variation in the magnitude of the response between preparations, which was sufficient to confound comparisons between different experiments and between animals. The variability between preparations could not be attributed to changes in sensitivity of PBL to mitogens or to the influence of erythrocyte contamination of the PBL preparations. While these results are in general agreement with previous reports of optimal conditions for the measurement of ruminant PBL to mitogens, there are some important differences which are discussed in the context of the available literature.     

The pharmacokinetics of cytarabine administered subcutaneously,combined with prednisone,in dogs with meningoencephalomyelitis of unknown etiology

The objective of this study was to describe the pharmacokinetics (PK) of cytarabine (CA) after subcutaneous (SC) administration to dogs with meningoencephalomyelitis of unknown etiology (MUE). Twelve dogs received a single SC dose of CA at 50 mg/m² as part of treatment of MUE. A sparse sampling technique was used to collect four blood samples from each dog from 0 to 360 min after administration. All dogs were concurrently receiving prednisone (0.5–2 mg kg^?1day^?1). Plasma CA concentrations were measured by HPLC, and pharmacokinetic parameters were estimated using nonlinear mixed‐effects modeling (NLME). Plasma drug concentrations ranged from 0.05 to 2.8 μg/ml. The population estimate (CV%) for elimination half‐life and Tmax of cytarabine in dogs was 1.09 (21.93) hr and 0.55 (51.03) hr, respectively. The volume of distribution per fraction absorbed was 976.31 (10.85%) ml/kg. Mean plasma concentration of CA for all dogs was above 1.0 μg/ml at the 30‐, 60‐, 90‐, and 120‐min time points. In this study, the pharmacokinetics of CA in dogs with MUE after a single 50 mg/m² SC injection in dogs was similar to what has been previously reported in healthy beagles; there was moderate variability in the population estimates in this clinical population of dogs.     

The effect of a 50% inspired mixture of nitrous oxide on arterial oxygen tension in spontaneously breathing horses anaesthetised with halothane

The effect of nitrous oxide (N₂O) on arterial partial pressure of oxygen (P_aO₂) was evaluated in 20 adult horses anaesthetised with halothane. A fresh gas flow rate of 20ml/kg/min, comprising a 1:1 N₂O/oxygen (O₂) mixture, was supplied via the rotameter flowmeters of an anaesthetic machine to a large animal breathing system. The horses breathed spontaneously from the circuit immediately after endotracheal intubation. Ten horses were subsequently positioned in lateral recumbency and ten in dorsal recumbency. A further twenty adult horses were anaesthetised with halothane and acted as controls; halothane in 20mls/kg/min of O₂ being supplied to the same breathing system. Fifty percent NO caused significant decreases in P_aO₂ for horses in lateral and dorsal recumbency. However when administered to horses in lateral recumbency it did not promote arterial hypoxaemia. There was a higher risk of intraopera- tive arterial hypoxaemia (P_aO₂ < 8.6kPa) associated with its use in spontaneously breathing horses in dorsal recumbency. Arterial hypoxaemia occurred in all horses during the first fifteen minutes of recovery but when N₂O was discontinued, halothane in oxygen supplied to the breathing circuit for five minutes at a flow rate of 20ml/kg/minute was sufficient to ensure that diffusion hypoxia did not occur. The magnitude of the hypoxaemia was not signficantly different between the groups. The time taken to adopt sternal recumbency was significantly shorter in the horses that had received N₂O.     

Recombinant Porcine Leptin Reduces Feed Intake and Stimulates Growth Hormone Secretion in Swine

Two experiments (EXP) were conducted to test the hypothesis that porcine leptin affects GH, insulin-like growth factor-I (IGF-I), insulin, thyroxine (T₄) secretion, and feed intake. In EXP I, prepuberal gilts received intracerebroventricular (ICV) leptin injections. Blood was collected every 15 min for 4 hr before and 3 hr after ICV injections of 0.9% saline (S; n = 3), 10 μg (n = 4), 50 μg (n = 4), or 100 μg (n = 4) of leptin in S. Pigs were fed each day at 0800 and 1700 hr over a 2-wk period before the EXP. On the day of the EXP, pigs were fed at 0800 hr and blood sampling started at 0900 h. After the last sample was collected, feeders were placed in all pens. Feed intake was monitored at 4, 20, and 44 hr after feed presentation. In EXP II, pituitary cells from prepuberal gilts were studied in primary culture to determine if leptin affects GH secretion at the level of the pituitary. On Day 4 of culture, 10⁵ cells/well were challenged with 10⁻¹², 10⁻¹⁰, 10⁻⁸, or 10⁻⁶ M [Ala¹⁵]-h growth hormone-releasing factor-(1-29)NH₂ (GRF), 10⁻¹⁴, 10⁻¹³, 10⁻¹², 10⁻¹¹, 10⁻¹⁰, 10⁻⁹, 10⁻⁸, 10⁻⁷, or 10⁻⁶ M leptin individually or in combinations with 10⁻⁸ and 10⁻⁶ M GRF. Secreted GH was measured at 4 hr after treatment. In EXP I, before injection, serum GH concentrations were similar. Serum GH concentrations increased (P < 0.01) after injection of 10 μg (21 ± 1 ng/ml), 50 μg (9 ± 1 ng/ml), and 100 μg (13 ± 1 ng/ml) of leptin compared with S (1 ± 2 ng/ml) treated pigs. The GH response to leptin was greater (P < 0.001) in 10 μg than 50 or 100 μg leptin-treated pigs. By 20 hr the 10, 50, and 100 μg doses of leptin reduced feed intake by 53% (P < 0.08), 76%, and 90% (P < 0.05), respectively, compared with S pigs. Serum IGF-I, insulin, T₄, glucose, and free fatty acids were unaffected by leptin treatment. In EXP II, relative to control (31 ± 2 ng/well), 10⁻¹⁰, 10⁻⁸, and 10⁻⁶ M GRF increased (P < 0.01) GH secretion by 131%, 156%, and 170%, respectively. Only 10⁻⁶ M and 10⁻⁷ M leptin increased (P < 0.01) GH secretion. Addition of 10⁻¹¹ and 10⁻⁹ M leptin in combination with 10⁻⁶ M GRF or 10⁻¹¹ M leptin in combination with 10⁻⁸ M GRF-suppressed (P < 0.05) GH secretion. These results indicate that leptin modulates GH secretion and, as shown in other species, leptin suppressed feed intake in the pig.     

Lymphocyte transformation test in veterinary clinical immunology

Lymphocyte transformation test is a powerful tool in laboratory testing of immunologic competence of animals. The impaired function of the lymphocytes or presence of mitogenesis suppressing factors in the patient serum were detected by comparing lymphocyte transformation (expressed as thymidine incorporation) obtained in media containing either autologous, homologous, or fetal calf serum additions. Most valuable results were obtained by using at least two, preferably three, different phytomitogens: concanavlin A (Con A), pokeweed mitogen (PWM), and pl ytohemagglutinin (PHA) at optimal concentrations (Con A, 15 μg/ml, PWM and PHA, 5 μg/ml) and decreased concentrations (Con A, 5 μg/ml, PWM and PHA, 1 μg/ml). Mitogenesis induced by lipopolysaccharide was considerably smaller and not used routinely. With 2 × 10⁵ lymphocytes/well, the background count of unstimulated lymphocytes in autologous serum in healthy dogs was usually between 100 and 400 counts/min (CPM), in clinically healthy cattle and horses from 200 to over 2000 CPM. Higher CPM were rarely detected without clinical disease. Increased background counts were often associated with viral infections, leukemias and lymphoreticular hyperplasias, decreased background counts were associated with various diseases. The stimulation indexes (SI) of healthy animals in autologous serum with Con A, (5 μg/ml) or PWM or PHA (1 μg/ml) were in the range from 100 to 1000 in the dogs, in the tens for Con A and in hundreds for PWM and PHA in horses and cattle. Increased SI were present during the incubation period of various diseases. Decreased SI were associated with numerous infectious and lymphoreticular diseases and were caused by any of the following: (1) the presence of serum immunosuppressive factor(s) in the patient serum, (2) the decreased response of lymphocytes to mitogens, or (3) increased mitogenicity of lymphocytes due to unidentified serum factors in absence of phytomitogens.     

Kinetics of intravenously administered lactose in cows

Four adult Norwegian Red cows were employed in an experiment designed to study the kinetics of lactose. The cows were given 50 g or 60 g of lactose by rapid intravenous injection of a 10 % lactose solution. Blood samples were taken at different intervals after injection, and lactose concentrations in the samples determined by an enzymatic/spectrophotometric method.The mean half-time for lactose elimination was 85.7 min, and for distribution 8.4 min. The mean apparent volume of distribution was calculated to be 0.189 1/kg, and total body clearance 1.55 ml min⁻¹ kg⁻¹.There was evidence to suggest that lactose mainly is eliminated renally from its distribution volume by glomerular filtration in the cow.     

A hematologic and blood chemical study of Swedish purchased calves.

The hemoglobin (Hb), packed cell volume (PCV), erythrocytes (R.G.), serum iron (SI) and unsaturated iron binding capacity (UIBG) were examined in a total of 386 purchased calves for the duration of 1 year. The calves were tested within 3 days of arrival at the buyer’s herd. The average age of the calves was 28 ± 10 days ().The results may be summarized as follows:

1. Approx. 35% of the calves had Hb values ≦ 10.0 g/100 ml.
2. Fifteen% of the calves had ≦ 6.0 × 10⁶ R.C. per µl.
3. Fifty-three calves or about 14% showed SI values ≦ 40 µg/100 ml and 131 calves or 34% ≦ 80 µg/100 ml.
4. Twenty-seven % of the calves had UIBG values > 501 µg/100 ml.
5. Almost half the calves (48%) had a saturation percentage of transferrin with iron below 20% and 138 calves (36%) below 15%.

These figures among others in the study indicate that 13–35% of the purchased calves suffered from iron deficiency anemia.     

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.     

Cerebral, renal, adrenal, intestinal, and pancreatic circulation in conscious ponies and during 1.0, 1.5, and 2.0 minimal alveolar concentrations of halothane-O2 anesthesia

Blood flow to the brain, kidneys, adrenal glands, pancreas, and small intestine was studied in 8 healthy ponies while awake (control) and during 1.0, 1.5, and 2.0 minimal alveolar concentrations (MAC) of anesthesia produced, using halothane vaporized in oxygen. During the anesthesia steps, intermittent positive-pressure ventilation was used to ensure isocapnia. Organ blood flow was determined with 15-micron (diameter) radionuclide-labeled microspheres, after allowing 30 minutes of equilibration at each of the 3 preestablished end-tidal halothane concentrations. The sequence of 1.0, 1.5, and 2.0 MAC levels of anesthesia (0.90, 1.35, and 1.80% end-tidal halothane) was randomized for every animal. In the awake ponies, cerebral blood flow in the cortical (106 +/- 15 ml/min/100 g) and deep gray (103 +/- 12 ml/min/100 g) matter was approximately 5-fold of that in the white matter (22 +/- 3 ml/min/100 g). In the brain stem, there was a decreasing gradient of blood flow from the cranial (thalamohypothalamus: 65 +/- 8 ml/min/100 g) to caudal regions (medulla: 34 +/- 5 ml/min/100 g). Vasodilatation occurred in all regions of the brain with halothane-O2 anesthesia; the decrease in vascular resistance reached its nadir at 1.5 MAC. In the medulla and pons, blood flow increased above control values, with each of the 3 concentrations of halothane, but in the midbrain and thalamohypothalamus, it remained similar to the control value. In the cerebral white matter and cerebellum, blood flow increased with 1.0 and 1.5 MAC of halothane anesthesia, whereas mean aortic pressure decreased to 91% and 74% of the control value. Blood flow in the cerebral cortex was not different from the control value, even at 2.0 MAC of halothane, despite a 49% reduction in perfusion pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Food intake and rumen motility in dwarf goats. Effects of some serotonin receptor agonists and antagonists

The serotonergic regulation of feeding behaviour has not so far been studied in ruminants. Therefore, the effects of some serotonin (5-HT) receptor agonists and antagonists on food intake and forestomach motility were studied in dwarf goats.Goats ate less food when treated intravenously (IV) with the 5-HT precursor 5-HTP (25 µg, 50 µg or 100 µg kg^–1 min^–1 over 15 min) than when they were treated with 5-HT (which does not pass the blood-brain barrier) or with saline. Accordingly, IV dexfenfluramine infusions (50 µg or 100 µg kg^–1 min^–1 over 15 min), which induces release of brain 5-HT, also led to dose-related reductions in food intake. In contrast, no anorectic effects were observed after IV infusions with the selective 5-HT reuptake inhibitor fluoxetine (100 µg kg^–1 min^–1 over 15 min), the selective 5-HT1A agonist 8-OH-DPAT (0.5 µg kg^–1 min^–1 over 15 min), or eltoprazine (4 or 8 µg kg^–1 min^–1 over 15 min), a mixed 5-HT1A/5HT1B receptor agonist. None of the 5-HT antagonists tested gave any increase in food consumption in this model. Interestingly, the non-selective 5-HT receptor antagonist methysergide (360 µg/kg IV) reduced food intake. This effect was most noticeable at 3 h after injection. The 5-HT3 receptor antagonist ondansetron (IV 10 µg kg^–1 min^–1 over 15 min) and the peripheral 5-HT2 receptor antagonist xylamidine (IV 100 µg kg^–1 min^–1 over 10 min) failed to modify food intake. These results provide evidence for central serotonergic involvement in the control of feeding. However, this control system differs markedly in goats and rodents.Dexfenfluramine, 5-HTP and eltoprazine administered at similar dose rates to those used in the food intake experiments induced some clinical signs including inhibition of forestomach contractions. These results, together with our earlierin vivo andin vitro observations, suggest that the inhibitory effects of serotonin receptor agonists on forestomach contractions are due to interactions with both peripheral and central serotonergic receptors. The change in smooth muscle tension, which leads to a change in the signals transmitted via vagal afferents to the central nervous system, appears not to modify feeding behaviour in dwarf goats.     

Efficacy of Chlorhexidine against Some Strains of Cultured and Clinically Isolated Microorganisms

The efficacy of chlorhexidine digluconate was determined against some strains of collected and clinically isolated bacteria and fungi. The efficacy was evaluated either by calculating a minimum inhibitory concentration (MIC) or by efficacy trials according to the guidelines of the European Committee for Standardization. The MIC values of chlorhexidine for Staphylococcus aureus, Microsporum gypseum, Microsporum canis and Trichophyton mentagrophytes were 0.625 g/ml, 12.5 g/ml, 50 g/ml and 6.25 g/ml, respectively. The in vitro efficacy of chlorhexidine was higher against ATCC strains of S. aureus and P. aeruginosa (0.5 mg/ml for 5 min and 0.5 mg/ml for 10 min, respectively) than against clinical isolates (0.5 mg/ml for 15 min and 1 mg/ml for 10 min, respectively). The antiseptic activity of aqueous solutions of chlorhexidine against spores of Bacillus subtilis, Bacillis sfericus and Clostridium perfringens required longer contact times than against the vegetative forms. Nevertheless, 5 mg/ml of chlorhexidine in water–ethanol 20:80 v/v was totally effective against the vegetative forms or spores of these microorganisms.     

The Use of Tannins to Control Salmonella Typhimurium Infections in Pigs

The aim of this study was to determine whether a hydrolysable tannin extract of sweet chestnut wood (Globatan^®) has an inhibitory effect on Salmonella Typhimurium survival both in vitro and in vivo in pigs. In a first experiment, the minimal inhibitory concentration of Globatan^® on 57 Salmonella Typhimurium isolates was determined. For all isolates, an MIC of 160–320 μg/ml was found. The second in vitro study revealed that Salmonella growth was strongly reduced using Globatan^® concentrations of 25–50 μg/ml and nearly completely inhibited at a concentration of 100 μg/ml Globatan^®. In an in vivo trial, two groups of six piglets, each group receiving feed with or without the addition of Globatan^® (3 g/kg), were orally inoculated with 10⁷ colony forming units of a Salmonella Typhimurium strain. Globatan^® had no effect on faecal excretion of Salmonella, and no differences in colonization of the intestines and internal organs were demonstrated in pigs euthanized at 4 days post‐inoculation. In conclusion, the hydrolysable tannin extract used in this study showed strong action against Salmonella Typhimurium in vitro but not in vivo.     

Resistance of Ovine,Caprine and Bovine Endothelial Cells to Clostridium perfringens Type D Epsilon Toxin In Vitro

Ovine, caprine and bovine endothelial cells were grown in vitro and challenged with Clostridium perfringens type D epsilon toxin to compare their susceptibility to this toxin. Madin Darby canine kidney (MDCK) cells, which are known to be susceptible to epsilon toxin, were used as a positive control. No morphological alterations were observed in any of the endothelial cell cultures tested, even after challenging with doses as high as 1200 MLD⁵⁰/ml of epsilon toxin. MDCK cells showed contour rounding and nuclear condensation as early as 30 min after exposure to 100 MLD⁵⁰/ml of epsilon toxin and after 60 min of exposure to 12.5 MLD⁵⁰/ml of the same toxin. All the MDCK cells were dead after 3 h of exposure to all concentrations of epsilon toxin. The results indicate that ovine, caprine and bovine endothelial cells are not morphologically responsive to the action of epsilon toxin in vitro.