High doses of methylprednisolone are required for the treatment of collagenase-induced intracerebral hemorrhage in rats

Methylprednisolone (MP) was evaluated for the treatment of intracerebral hemorrhage in a Sprague-Dawley rat model of cerebral hematoma induced by subcortical injection of collagenase. At 1 and 24 h after the injection, MP was administered intraperitoneally (IP) at a concentration of 10, 35, or 100 mg/kg. Control groups received saline IP at 1 and 24 h after the intracerebral injection of collagenase (positive controls) or saline (negative controls). Motor behaviour 24 h before and 24 h and 48 h after the intracerebral injection was evaluated by means of a neurologic exam and a rotarod treadmill test. The animals were euthanized at 48 h; brain water content was determined in half of the rats, and histopathological studies were done in the other half. Compared with the positive controls, the animals with collagenase-induced hematoma performed significantly better on the neurologic exam after treatment with 100 mg/kg of MP and on the rotarod test after treatment with 35 or 100 mg/kg of MP. The hematoma volume was significantly smaller (P < 0.002) after all doses of MP; however, the smallest volume was seen with 100 mg/kg. There were significantly fewer neutrophils (P < 0.01) within the hematoma in the MP-treated animals (maximum reduction with 100 mg/kg) than in the positive controls, but the numbers of reactive astrocytes did not differ significantly between the treatment groups. The number of necrotic neurons in the penumbra did not differ between the treatment groups; however, there were significantly fewer (P < 0.005) in the cerebral cortex in the group treated with 100 mg/kg of MP compared with the positive controls. These results suggest that high doses of MP administered shortly after occurrence of a cerebral hematoma are beneficial for the treatment of intracerebral hemorrhage.     

Evaluation of dexamethasone for the treatment of intracerebral hemorrhage using a collagenase-induced intracerebral hematoma model in rats

Dexamethasone was evaluated for the treatment of intracerebral hemorrhage using a rat model of cerebral hematoma induced by intracerebral injection of collagenase. The treatment group consisted of hematoma rats receiving dexamethasone 1 mg/kg intraperitoneal (i.p.) at 1 and 24 h following surgery. Controls included hematoma rats receiving saline i.p. and sham-operated animals receiving saline i.p. Each animal was evaluated neurologically prior to, as well as 24 and 48 h following surgery. After the last neurological evaluation, animals were deeply anesthetized and the brain was removed following perfusion for microscopic examination and glial fibrillary acidic protein immunohistochemistry. Behavioral scores were significantly improved in the treated group (P < 0.0001). The hematoma volume was significantly smaller (P < 0.02). Neutrophils and astrocytes were less numerous in the hematoma of dexamethasone-treated animals (P < 0.001), however the number of necrotic neurons in the penumbra was not changed by the treatment. The number of necrotic neurons in the cerebral cortex was less in treated than in nontreated animals (P < 0.01). Controls had many vascular changes including necrotic endothelium and fibrin deposits compared with treated animals. In conclusion, dexamethasone administered shortly after an intracerebral hematoma appears beneficial for the treatment of this condition.     

Long-term effects of meloxicam in the treatment of respiratory disease in fattening cattle

The long-term effects of a single dose of meloxicam (Metacam 20 mg/ml; Boehringer Ingelheim Vetmedica) in conjunction with antibiotic therapy in cattle with clinical signs of bovine respiratory disease (BRD) was evaluated in a blind, controlled, randomised study. Two hundred animals with clinical signs of brd received a single subcutaneous injection of 20 mg/kg oxytetracycline; 100 of them also received a subcutaneous injection of 0.5 mg/kg meloxicam, and the other 100 received an injection of isotonic saline. The animals were weighed before they were treated and seven, 35, 70 and 105 days later, and finally before they were slaughtered. The mean bodyweight of the meloxicam-treated animals was significantly higher from day 70 until slaughter, and the mean average daily weight gain until slaughter and the mean carcase weight of the animals treated with meloxicam were significantly higher. In the animals with lung lesions, significantly less lung tissue was affected in those that had been treated with meloxicam.     

Effects of dexamethasone on emesis in cats sedated with xylazine hydrochloride

OBJECTIVE: To determine antiemetic efficacy of prophylactic administration of dexamethasone and its influence on sedation in cats sedated with xylazine hydrochloride. ANIMALS: 6 healthy adult cats (3 males and 3 females). PROCEDURE: The prophylactic antiemetic effect of 4 doses of dexamethasone (1, 2, 4, and 8 mg/kg of body weight, IM) or saline (0.9% NaCl) solution (0.066 ml/kg, IM) administered 1 hour before administration of xylazine (0.66 mg/kg, IM) was evaluated. Cats initially were given saline treatment (day 0) and were given sequentially increasing doses of xylazine on days 7, 14, 21, and 28. After xylazine injection, all cats were observed for 30 minutes to allow assessment of frequency of emesis and time until onset of the first emetic episode.The influence of dexamethasone on xylazine-induced sedation in these cats also was evaluated. RESULTS: Prior treatment with 4 or 8 mg/kg of dexamethasone significantly reduced the frequency of emetic episodes and also significantly prolonged the time until onset of the first emetic episode after xylazine injection. Time until onset of the first emetic episode also was significantly prolonged for dexamethasone at a dose of 2 mg/kg. Time until onset of sedation after administration of xylazine was not altered by administration of dexamethasone. CONCLUSIONS AND CLINICAL RELEVANCE: Dexamethasone (4 or 8 mg/kg, IM) significantly decreased the frequency of emetic episodes induced by xylazine without compromising sedative effects in cats. Dexamethasone may be used prophylactically as an antiemetic in cats treated with xylazine.     

Efficacy of tulathromycin in the treatment of respiratory disease in pigs caused by Actinobacillus pleuropneumoniae

The efficacy of a single dose of tulathromycin, a novel triamilide antimicrobial of the macrolide class, given at 2.5 mg/kg or 5 mg/kg bodyweight, or three daily doses of ceftiofur, given at 3 mg/kg bodyweight, was evaluated in pigs with respiratory disease induced experimentally with Actinobacillus pleuropneumoniae. On day 0, 100 pigs with clinical signs of respiratory disease were randomly assigned to groups of 25 pigs, which were treated with either saline, one of the doses of tulathromycin, or ceftiofur. The pigs' rectal temperatures and clinical scores for respiratory signs and general attitude were recorded daily until day 10. Animals withdrawn from the study for welfare reasons were recorded. On day 10, the animals remaining in the study were weighed, euthanased and examined postmortem. Three of the animals treated with saline and one of those treated with 2.5 mg/kg tulathromycin were withdrawn from the study, but none of those treated with 5 mg/kg tulathromycin or ceftiofur were withdrawn. The least squares mean bodyweight gains of the pigs treated with the antimicrobial agents were significantly (P<0.05) higher than that of the saline-treated group, and the least squares mean percentages of the total lung involvement and incidence of respiratory disease associated with A. pleuropneumoniae were significantly (P<0.05) lower, but there were no significant differences between the three groups of pigs treated with the antimicrobial agents.     

Chemotherapy of porcine cysticercosis with albendazole sulphoxide

Cysticercosis is a zoonotic disease of humans produced by the larval stage of swine parasite, Taenia solium. Chemotherapy of infected pigs is a possible strategy for avoiding disease transmission and improving health programs in endemic areas of cysticercosis. In this preliminary study, seven naturally infected pigs from 6 to 12 months of age were allotted to treated (n = 4) and control groups (n = 3). The treated animals received a subcutaneous injection in their forelegs and thighs of 15 mg/kg per body weight of albendazole sulphoxide (ABZSO; Pisa, Mexico) once per day for 8 days. At the same time, the control group received a subcutaneous injection of saline solution (9% NaCl). After 12 weeks, all the animals were slaughtered and at least 200 metacestodes were isolated from the muscles and brain of each animal. Using histology and the metacestode viability criteria described in this study, treated animals had no viable cysts in their muscle (0/200), while 7 of 17 (41.1%) viable cysts were observed in those isolated from their brains. In the control group, 183/200 (91.5%) muscle metacestodes were viable and from brain, 22/29 (75.8%) metacestodes were viable. The 15 mg/kg per body weight dosage of ABZSO was 100% effective against muscular cysticercosis as shown by the lack of viable cysts and the micro-calcifications in meat from the treated pigs.     

Brain monoamine concentrations in turkey poults infected with Bordetella avium

Six hours post-hatch, large white turkey poults were inoculated intranasally with 5 X 10(7) organisms of the "W" isolate of Bordetella avium. Three hours after inoculation and subsequently on days 7, 10, 14, 21, and 28 postinoculation, 30 infected and 30 uninfected control poults were injected intramuscularly with alpha methylparatyrosine (AMPT, 250 mg/kg), and an additional 30 of each group received a saline vehicle. Three hours after AMPT injection, whole brains from treated and untreated poults from both infected and control groups were removed, weighed, and frozen until assayed for norepinephrine (NE), dopamine (DA), and serotonin (5-HT). B. avium-infected poults had a significant reduction in steady-state NE and Da and a greater depletion of NE and DA after AMPT treatment compared with control poults. Infected poults had significantly reduced whole brain 5-HT concentrations, which persisted through 21 days postinoculation. Altered brain NE, DA, and 5-HT concentrations suggest that the B. avium-infected poults may be less able to cope with additional stressors.     

Effects of extracorporeal shock wave therapy on desmitis of the accessory ligament of the deep digital flexor tendon in the horse

Objective: To evaluate the effects of extracorporeal shock wave therapy (ESWT) on collagenase‐induced lesions in the accessory ligament of the deep digital flexor tendon (ALDDFT) of horses. Study Design: Paired, blinded controlled study. Animals: Eight Thoroughbred horses (3 mares, 5 geldings; mean±SD weight, 464±26 kg, mean age, 8±1.7 years). Methods: Lesions were created in both ALDDFTs of all horses by injection of 2 × 10³ IU of collagenase type I. Percent lesion and structure (fiber alignment and echogenicity) were quantified with ultrasonographic imaging 3, 6, and 9 weeks after collagenase injection. After ultrasound examinations, ESWT (1000 shocks at 0.15 mJ/mm²) was applied to 1 ALDDFT in each horse. ALDDFT were harvested 15 weeks after collagenase injection and the microstructure, mRNA levels of collagen types I and III, and collagen and glycosaminoglycan content were evaluated. Results: There were no differences in percent lesion, echogenicity, or fiber alignment between control‐ and ESWT‐treated ligaments at each evaluation time; however, compared with 3‐week values, there was a significant increase in percent lesion and echogenicity for EWST treated ligaments at 6 weeks and significant decrease in both variables for treated and control ligaments at 12 weeks. Fiber alignment improved significantly at 9 weeks in controls and at 12 weeks in treated and control ligaments. Collagen type I mRNA levels were significantly higher in the ESWT treatment group compared with the control group 15 weeks after collagenase injection though differences in other mRNA levels, microstructure, and composition were not significant. Conclusions: Our results do not support an effect of ESWT on collagenase‐induced lesions in the equine ALDDFT.     

The effect of hypertonic saline solution on vasodilatation of the superior sagittal sinus using magnetic resonance imaging in normovolemic dogs

Several animal studies have demonstrated the beneficial effects of hypertonic saline (HSS) on cerebral blood flow, intracranial pressure and brain water content. This study aimed to investigate, using magnetic resonance imaging, whether a small volume of HSS is superior to dextran in vasodilatation of cerebral vessels and reduction of cerebrospinal fluids in dogs. HSS induced a significant expansion of the cross-section of the superior sagittal sinus in the axial transverse section of the pituitary and a decrease in cerebrospinal fluid area in the axial transverse section of the epencephalon more than dextran 40 did (p<0.001, respectively). However, the relative plasma volume in the dog which received dextran 40 was significantly higher after t=30min than in the HSS group (p<0.001). Therefore, it is suggested that HSS might be superior to colloid solutions in improving cerebral circulation, whereas dextran 40 is superior to HSS in enhancing systemic circulation in dogs.     

Effects of high CO2 level during early incubation and late incubation in ovo dexamethasone injection on perinatal embryonic parameters and post-hatch growth of broilers

1. A total of 1200 Cobb broiler breeder eggs were incubated under either standard conditions (C group) or high CO(2) levels (CO(2) group) during the first 10 d of incubation. The CO(2) level of the CO(2) incubator was attained gradually by a natural build-up of CO(2) due to air-tight closure of the incubator. From d 10 of incubation onwards, all eggs were incubated under standard incubation conditions. At d 18 of incubation, the eggs of both incubation groups (CO(2) and C group) were either injected with water-soluble dexamethasone (DEXA group) or with saline (0.9% NaCl; saline group) or were not injected (control). 2. Body weights, plasma hormonal concentrations (T(3), T(4) and corticosteroid) and glucose concentrations were measured regularly during the perinatal (at IP, internal pipping) and post-hatch period (at 1, 2, 4 and 6 weeks post-hatch). Additionally, hatchability and pattern of embryonic mortality were determined after hatch. 3. The results showed that high CO(2) levels during the first 10 d of incubation or dexamethasone injection at d 18 of incubation decreased embryo mortality, mainly because of a reduction in embryo malpositioning. However, a combination of a CO(2) incubation and a dexamethasone injection led to an increase in embryo mortality and therefore a decrease in hatchability. 4. Although dexamethasone injection at embryonic d 18 decreased body weight in the second week of the rearing period and CO(2) incubation increased body weight during the first 2 weeks of the rearing period, no consistent effect of both the incubation and injection treatments on body weight at slaughter age was observed.     

Effects of an extract of Gingko biloba on bromethalin-induced cerebral lipid peroxidation and edema in rats.

The effects of administration of a commercially available extract of Gingko biloba (EGB) on bromethalin-induced brain lipid peroxidation and cerebral edema in adult male Sprague-Dawley rats was determined. Gingko biloba extract was given (100 mg/kg) by gavage immediately after bromethalin (1.0 mg/kg) administration. Rats were euthanatized at 24 hours after dosing. Brain lipid peroxidation was determined by measurement of brain malonaldehyde-thiobarbituric acid chromophore (MDA-TBA) concentration, brain sodium concentration, and brain water content. Treatment of bromethalin-dosed rats (10/group) with EGB was associated with a statistically significant (P less than 0.05) decrease in clinical sign severity, compared with bromethalin-dosed saline solution-treated rats. All rats given bromethalin and saline solution developed clinical signs of toxicosis including CNS depression, hind limb weakness, ataxia, paralysis, and coma. Some rats given bromethalin and EGB developed clinical signs, however, none developed hind limb paralysis. The brain MDA-TBA concentration (2.4 +/- 0.5 delta MDA-TBA concentration/mg of protein), percentage of water in brain tissue (80.3 +/- 0.30%), and brain sodium concentration (6.68 +/- 0.21 mg/g of dry weight) were significantly increased in rats given bromethalin and saline solution, compared with control rats given saline solution (1.0 +/- 0.1 delta MDA-TBA concentration/mg of protein; 78.1 +/- 0.33% water in brain tissue; 4.83 +/- 0.30 mg of brain Na+/g of dry weight) and rats given bromethalin and EGB (1.6 +/- 0.2 delta MDA-TBA concentration/mg of protein; 79.3 +/- 0.31% water in brain tissue; 5.37 +/- 0.34 mg of brain Na+/g of dry weight).(ABSTRACT TRUNCATED AT 250 WORDS)     

山豆根多糖对感染PRRSV小鼠脾脏细胞因子水平的影响

探讨山豆根多糖对PRRSV感染小鼠脾淋巴细胞分泌细胞因子水平的影响。将70只昆明种小鼠随机分为7组(A组、B组、C组、D组、E组、F组、G组),每组10只,雌雄各半,依据前期已经建立氧化应激模型的感染条件,D组、E组、F组、G组小鼠于试验第1、2、3天分别采用口服、滴鼻和腹腔注射3种途径联合感染PRRSV病毒原液1.0mL/只,A组、B组、C组给予生理盐水1.0mL/只。第4、5、6天,A、D组小鼠分别腹腔注射生理盐水,0.2mL/10g。B组小鼠腹腔注射5.0mg/kg的脂多糖(LPS)溶液,C组、E组、F组、G组小鼠分别腹腔注射不同剂量的山豆根多糖(200、50、100、200mg/kg)。供试小鼠均于第14天处死,并取其脾脏制备匀浆。采用ELISA检测脾匀浆中TNF-α、IL-1β、IL-6、IL-8、IL-10和MCP-1等细胞因子的水平。结果显示,PRRSV感染小鼠后能升高小鼠脾脏匀浆内TNF-α、IL-1β、IL-6、IL-8、IL-10和MCP-1水平,50mg/kg~100mg/kg剂量的山豆根多糖能降低上述细胞因子的水平。结果表明,山豆根多糖能有效降低PRRSV感染小鼠脾脏细胞因子的水平。     

Evaluation of intraperitoneal and incisional lidocaine or bupivacaine for analgesia following ovariohysterectomy in the dog

Objective To determine if intraperitoneal (IP) and incisional (SC) lidocaine or bupivacaine provide analgesia following ovariohysterectomy (OHE). Study Design Prospective, randomized, controlled, blinded clinical trial. Animals Thirty dogs presenting to the Veterinary Teaching Hospital for elective OHE. Methods Dogs were pre‐medicated with acepromazine and butorphanol, induced with thiopental and maintained with isoflurane. They were randomly assigned to three groups: 10 received 8.8 mg kg^?1 2% lidocaine with epinephrine IP (LID); 10 received 4.4 mg kg^?1 0.75% bupivacaine IP (BUP); and 10 received 0.9% saline IP (SAL) upon completion of OHE. All IP doses were standardized to 0.88 mL kg^?1 with saline. An additional 2 mL of undiluted solution was placed SC prior to incisional closure. Dogs were scored at 0.5, 1, 2, 3, 6, 8 and 18 hours post‐extubation by one observer. Dogs were evaluated using a visual analogue scale (VAS) for pain and sedation, and a composite pain scale (CPS) that included physiologic and behavioral variables. Dogs were treated with 0.22 mg kg^?1 butorphanol + acepromazine if their VAS (pain) score was >50. Parametric variables were analyzed using Student's t‐test or repeated measures anova as appropriate. Non‐parametric variables were analyzed by χ²‐test. Results There were no significant differences in age, weight, incision length, surgery time, anesthesia time, or total thiopental dose among groups. Peak post‐surgical pain scores for all groups occurred at 0.5 hours and returned to baseline by 18 hours. Dogs in the BUP group had significantly lower VAS‐pain scores overall than dogs in the SAL group. Seven out of 10 dogs in the SAL group, 4/10 in the LID group and 2/10 in the BUP group were treated with supplemental acepromazine and butorphanol. No differences between groups were detected with the CPS. No adverse side‐effects were observed. Conclusions and clinical relevance Our findings support the use of IP and SC bupivacaine for post‐operative analgesia following OHE in the dog.     

Effect of repeated administration of tirilazad mesylate on healthy and endotoxemic calves: a pilot study.

Tirilazad mesylate (TM:U74006F), a nonglucocorticoid 21-aminosteroid (lazaroid), is beneficial in the treatment of experimentally-induced ischemic injury following brain and spinal cord trauma, subarachnoid hemorrhage, hypovolemic shock and endotoxemia. This study investigated the effects of TM following repeated administration in sixteen healthy and endotoxemic calves. Group A calves received TM 3 mg/kg IV; group B calves received Escherichia coli endotoxin in increasing doses (0.1 to 20 micrograms/kg IV); group C calves received TM and endotoxin and group D calves received sterile saline (10 mL). Endotoxin, TM and saline were given every eight hours for five days. Mild, transient tachypnea was observed following TM administration. The drug suppressed clinical signs of endotoxemia until larger doses of endotoxin were given. At necropsy no substantial lesions were observed in groups A and D. Groups B and C had lesions consistent with endotoxemia but only group C calves had evidence of abomasal and ruminal ulceration. Although TM may be of benefit in the treatment of endotoxemia, further studies are needed to determine the optimal dosage and potential side effects in the endotoxic bovine neonate.     

Efficacy of long-acting oxytetracycline for the prevention of tick-borne fever in calves

Twenty-six calves which had not previously grazed tick-infested pasture were divided into two equal groups. On May 26, 1988 (day 0) they were turned out into a field of rough grazing where cases of redwater fever had occurred the previous spring. Seven, 14, 21 and 28 days after the start of the trial the animals in one group each received an intramuscular injection of 20 mg/kg bodyweight of long-acting oxytetracycline. During the 60 days of the trial the animals received a severe tick-borne fever challenge, in some cases combined with a redwater fever challenge. An unforeseen complicating factor was the presence of animals persistently infected with bovine viral diarrhoea virus, present in almost equal numbers in both groups. At the end of the trial the treated group weighed on average 16 kg more than the control group, a difference which was attributed to the suppression of tick-borne fever by oxytetracycline.     

Inhibition of Angiotensin‐Converting Enzyme Increases Oestradiol Production in Ewes Submitted to Oestrous Synchronization Protocol

This study aimed at evaluating the effects of angiotensin‐converting enzyme inhibitor (enalapril) and angiotensin II antagonist (valsartan) on the oestradiol and progesterone production in ewes submitted to oestrous synchronization protocol. The animals were weighed and randomly divided into three groups (n = 7). A pre‐experiment conducted to verify the effectiveness and toxicity of enalapril (0.5 mg/kg LW) and valsartan (2.2 mg/kg LW) showed that, in the doses used, these drugs were effective in reducing blood pressure without producing toxic effects. In the experiment, all animals were subjected to oestrous synchronization protocol during 12 days. On D10, D11 and D12, animals received saline, enalapril or valsartan (same doses of the pre‐experiment), according to the group randomly divided. The hormonal analysis showed an increase in oestradiol on the last day of the protocol (D12) in animals that received enalapril (p < 0.05), but not in other groups, without changing the concentration of progesterone in any of the treatments. It is concluded that valsartan and enalapril are safe and effective subcutaneously for use in sheep and that the angiotensin‐converting enzyme (ACE) inhibition with enalapril leads to an increase in oestradiol production near ovulation without changing the concentration of progesterone. This shows that ACE inhibition may be a useful tool in reproductive biotechnologies involving induction and synchronization of oestrus and ovulation in sheep.     

Anti-inflammatory therapy in acute endotoxin-induced bovine mastitis

Acute mastitis was induced in lactating cows by intramammary challenge with 10 g of Escherichia coli lipopolysaccharide. The cows were monitored clinically prior to and for 96 hours after challenge. Milk production, complete blood counts, serum enzyme activities and milk indicators of inflammation were evaluated.Endotoxin challenge was in 7 groups of 3 cows each. Within the groups, cows were randomly assigned to 3 intravenous treatments: saline controls, steroid (one dose of dexamethasone at 0.44 mg/kg) and non-steroidal agent (two doses of flunixin meglumine at 1.1 mg/kg, 8 h apart).Anti-inflammatory therapy reduced rectal and mammary gland surface temperatures. Milk production was significantly reduced (p<0.05) in cows treated with dexamethasone. Although dexamethasone treatment produced significant increases (p<0.05) in blood leukocytes and segmented neutrophils, milk somatic cell concentrations were not significantly altered. Flunixin meglumine did not alter milk production or blood or milk leukocytes.     

Cell Response Associated to NaCI Effect in a Freshwater Telecost Epidermis

Sixteen adult fresh water teleosts ( Pimelodus maculatus) were used in an examination of the effect of salt water on the ultrastructure of the epidermis. Six animals were treated for 3 hours with 2% saline and six were treated with 1% saline for 8 hours. No diffrenences between treated groups were noted. Four animals served as untreated controls. Both transmission and freeze-facture electonmicroscopy was utilized in examining the epidermis.
The significant alterations in epidermis were observed within the superficial cell layer, in which a decreased density of micropolicae occurred, suggesting streching of the cell surface. An increased intercellular space was also observed in this layer. The cells demonstrated an increase in intracytoplasmic vesicles, and an enhancement of Golgi membranes in treated animals as compared to untreated animals.     

Selenium and vitamin E effect on antibody production of sheep vaccinated against enzootic abortion (Chlamydia psittaci)

The effect of selenium (Se) and vitamin E (vit E) on antibody production of sheep vaccinated against Chlamydia psittaci (ovis) was investigated. Thirty-two sheep, one year old, seronegative to Chlamydia infection, vaccinated against enterotoxemia and dewormed were used. Injectable sodium selenite (0.1 mg/kg b.w.) was given twice to animals of the first group (gSe), with a three week interval. The sheep of the second group (gE) received 1 g vit E each orally, six times at weekly intervals. The animals of the third group (gSeE) were given Se and vit E in doses and routes of administration as in gSe and gE. The animals of the fourth group served as controls (gC) and injected normal saline. The first vaccination was made at the time that the second Se injection was given. Revaccination was made two weeks later. The experiment lasted 29 weeks. The results indicated that Se alone led to a significant increase of Chlamydia antibody response (P < 0.05), but not when it was given in combination with vit E. Animals that received vit E (gE) had much lower titres, just above of those of the controls.     

Effects of low dosages of intravenous dexamethasone on serum cortisol concentrations in the normal cat

The suppressive effects of three different low dosages of dexamethasone (5, 10 and 15 micrograms kg-1) on serum cortisol concentrations were evaluated in 10 normal cats. On four different days, serum was collected before and at two, four, six and eight hours after the intravenous administration of saline or dexamethasone. Following the administration of saline, no significant difference in mean serum cortisol concentrations was noted between the basal or postinjection values. In contrast, mean serum cortisol concentrations decreased significantly (P less than 0.05) by two hours and remained significantly below mean basal values eight hours after injection of all three dosages of dexamethasone. The degree of cortisol suppression became progressively greater as the dosages of dexamethasone were increased. After administration of the highest dose of dexamethasone (15 micrograms kg-1), serum cortisol decreased to below 5 ng ml-1 by two to four hours and remained suppressed (under 5 ng ml-1) eight hours after injection in all cats. In contrast, two of the 10 cats showed a slight escape from cortisol suppression by eight hours after injection of dexamethasone at the dosage of 10 micrograms kg-1, whereas a dosage of 5 micrograms kg-1 failed to suppress cortisol concentrations below 10 ng ml-1 at any of the sampling times in one cat and was associated with increasing serum cortisol concentrations at eight hours after injection in three cats.(ABSTRACT TRUNCATED AT 250 WORDS)