The effects of ACTH, prednisolone and Escherichia coli endotoxin on some clinical haematological and blood biochemical parameters in dwarf goats

Serum alkaline phosphatase activity during zinc deficiency and long-term inflammatory stress

A decrease in serum zinc can be caused by a real zinc deficiency but can also be caused by an apparent zinc deficiency, e.g. in inflammatory stress. The aim of this study was to evaluate the diagnostic power of serum alkaline phosphatase (AP) activity in the discrimination between pathophysiologic states of "real" and "apparent" zinc deficiency. A decrease in serum zinc was induced in growing and adult rats, by providing a diet low in zinc and by causing inflammatory stress. AP activity was determined using reagents low or enriched in zinc. Serum AP was decreased in zinc-deficient adult rats (P < 0.01). In zinc-deficient growing rats AP activity was not different from normal rats but AP activity decreased rapidly. In the same growing rats a significant difference was found in AP activities determined using buffers low and enriched in zinc (P < 0.001) between both groups of rats. After inducing inflammatory stress a decrease in AP activity (P < 0.01) and serum zinc (P < 0.001) was seen during the first few days. After the initial phase of inflammation AP activity normalized, serum zinc showed a rise which after correction for the decrease in serum albumin reached the level of the control rats. A difference in AP activity in buffers low and enriched in zinc was observed only during the first few days after induction of inflammatory stress (P < 0.001). Probably the method of measurement of the difference in enzyme activity, using buffers low and enriched in zinc, can be used as an indication for zinc deficiency in situations with changing AP enzyme concentrations. AP activity is decreased during the initial phase of inflammatory stress due to a decrease in serum zinc.

Effects of flurbiprofen on recombinant human IL-1 alpha-induced fever and associated clinical, haematological and blood biochemical changes in the dwarf goat

Flurbiprofen, a potent NSAID, was given as an intravenous infusion (1 mg/kg) to dwarf goats. After drug administration, no significant changes were observed in heart rate and rumen motility, whereas rectal temperature increased slightly; mean plasma glucose and creatinine concentrations gradually increased during the observation period. Plasma iron concentration and the number of circulating lymphocytes were significantly lower after flurbiprofen infusion. Intravenous injection of recombinant human interleukin-1 alpha (r. HuIL-1 alpha: 0.5 microgram/kg) caused shivering, fever, inhibition of rumen contractions, tachycardia, hypoferraemia, hypozincaemia, hyperglycaemia followed by hypoglycaemia, changes in plasma urea and creatinine values, lymphopaenia and neutropaenia followed by neutrophilic leukocytosis. Pretreatment with flurbiprofen partly antagonized the febrile reactions to r.HuIL-1 alpha. The r.HuIL-1 alpha-induced tachycardia and inhibition of rumen contractions were only delayed. The drug prevented the initial hyperglycaemia but did not abolish the secondary hypoglycaemia. Furthermore, flurbiprofen delayed the decline in plasma zinc and iron concentrations, whereas plasma creatinine values were significantly lower. Finally, after drug pretreatment the changes in circulating neutrophils were more pronounced. These data demonstrate that most of the haematological, blood biochemical, and clinical effects of r.HuIL-1 alpha cannot be blocked by flurbiprofen, suggesting that an increased synthesis of prostaglandins is not involved in these r.HuIL-1 alpha-induced effects.

Effect of ambient temperature and E. coli endotoxin upon the plasma iron level in wild house mice in winter season

The effects of ambient temperatures of 10 degrees C and 30 degrees C and of E. coli endotoxin on brain temperature and plasma iron level were investigated in unrestrained wild house mice, Mus musculus. In control animals (i.p. saline-injected) exposed to cold environment the brain temperature decreased and plasma iron levels were lower than those observed under thermoneutral conditions (30 degrees C). Animals injected i.p. with endotoxin (0.5 micrograms.kg-1) and placed at 30 degrees C showed a drop in plasma iron level during the fever episode. The results provide strong evidence for a relationship between brain temperature and plasma iron level in control mice under thermoneutral conditions, and show that during cold exposure or after injection of endotoxin, there is no linear correlation between brain temperature and plasma iron. Moreover, it was found that cold stress influences plasma iron level and that this influence is not mediated by changes in brain temperature.

The influence of anti-inflammatory therapy on bacterial clearance following intramammary Escherichia coli challenge in goats

Coliform mastitis in dairy cattle frequently results in systemic disease with occasional deaths in association with endotoxic shock. Systemic anti-inflammatory therapy has been used to alter the course of endotoxic shock in severe cases. Use of anti-inflammatory therapy has been questioned on the basis that such treatment may compromise immune function and decrease clearance of bacteria from infected mammary glands. The purpose of this investigation was to determine whether anti-inflammatory therapy influenced bacterial clearance following intramammary challenge of lactating goats with Escherichia coli. Standardized quantities of a pathogenic coliform culture were infused through the teat canal into one half of the mammary gland in 18 goat does. The does were then randomly assigned to receive one of three intravenous treatments: saline (controls), one dose of steroid (dexamethasone), or two doses of a non-steroidal anti-inflammatory agent (flunixin meglumine). The clinical signs, milk production, complete blood counts, serum clinical chemistry values, milk bacterial cultures and milk somatic cell concentrations were monitored sequentially. Goats treated with anti-inflammatory agents exhibited some improvement in clinical response to challenge with E. coli (e.g. rectal temperature, degree of appetite suppression) as compared to saline controls. There were no significant differences between treatments in the degree of inflammation present in the mammary glands or supramammary lymph nodes examined at necropsy. The most important finding was that anti-inflammatory therapy did not adversely influence the clearance of E. coli from challenged glands.

Fever and changes in plasma zinc and iron concentrations in the goat. The effects of interferon inducers and recombinant IFN-alpha 2a

Inflammation or invasion by pathogenic micro-organisms induces systemic changes, collectively known as the acute phase response. Among the varied alterations that together produce this response are fever, hypoferraemia and hypozincaemia. It is likely that these responses are mediated, in part, by production and release of cytokines such as interleukin-1 (Il-1), interferons (IFN-alpha) and tumour necrosis factor (TNF). The present report describes a comparative study in dwarf goats on recombinant human IFN-alpha 2a (0.5 x 10(5) IU per kg intravenously (i.v.) and 0.5 x 10(6) IU per kg intramuscularly (i.m.], Poly I:Poly C (an interferon inducer; 30 micrograms per kg i.v.), Newcastle disease virus La Sota strain (an interferon inducer; 0.5 ml per kg i.v.) and Escherichia coli endotoxin (an Il-1 and TNF inducer; 0.1 microgram per kg i.v.). The i.v. injection of recombinant IFN-alpha 2a caused characteristic monophasic febrile reactions, but no significant changes in plasma zinc and iron concentrations. The temperature responses were not due to endotoxin contamination because polymyxin B, which blocks endotoxin, had no inhibitory effect on the pyrogenicity of IFN-alpha 2a. In contrast, the IFN-alpha 2a-induced fever was completely prevented by flurbiprofen pretreatment (1 mg per kg i.v.). In contrast to the i.v. administration, i.m. injection of IFN-alpha 2a caused fever, hypoferraemia and hypozincaemia. Similar results were obtained after E. coli endotoxin, NCD La Sota strain and Poly I:Poly C injection. However, the shapes of the temperature curves and the changes in trace metal concentrations were markedly different. These data support the theory that fever and the changes in plasma zinc and iron concentrations are regulated by different mechanisms.

Appetite-modulating drugs in dwarf goats, with special emphasis on benzodiazepine-induced hyperphagia and its antagonism by flumazenil and RO 15-3505

In dwarf goats fasted for 2 h, i.v. administration of the benzodiazepine (BZ) agonists diazepam (60 micrograms/kg), brotizolam (2 and 4 micrograms/kg) and climazolam (100 micrograms/kg) induced hyperphagic effects, whereas i.v. injections of the BZ-antagonist flumazenil (R degrees 15-1788; 0.5 mg/kg), the anthelmintic ivermectin (0.1 mg/kg), the 5-HT2 antagonist ritanserine (0.1 mg/kg), ACTH (10 micrograms/kg) and prednisolone (1 mg/kg) were inactive in a 30-min feeding test. Both the BZ-antagonist R degrees 15-3505 (greater than or equal to 0.1 mg/kg) and the opiate receptor antagonist naloxone (0.1 mg/kg) had anorectic effects in dwarf goats given 30 min access to a palatable pelleted concentrate. The hyperphagic effects of climazolam and brotizolam were not antagonized by flumazenil, whereas similar doses of this drug completely reversed muscle incoordination and ataxia induced by much higher doses of these BZ-agonists. In the combination experiments with naloxone and BZ-agonists, naloxone antagonized the hyperphagic effects of both diazepam and brotizolam. Similarly, in the diazepam-R degrees 15-3505 study, there was a significant effect of diazepam and a significant inhibition of this effect by R degrees 15-3505 (50 micrograms/kg). In the diazepam-ivermectin combination experiment no evidence for drug potentiation was found. These results and the mode of action of the above mentioned drugs are discussed in relation to feeding behaviour.

Effect of steroidal anti-inflammatory drugs on Escherichia coli endotoxin-induced mastitis in the cow

Effects of intramammary infusion of prednisolone (40 mg) or intramuscular injection of dexamethasone (30 mg) or flumethasone (5 mg) on local and systemic signs in Escherichia coli endotoxin-induced mastitis were studied. The effect of varying intervals (0, 2, and 4 h) between intramammary infusion of endotoxin and prednisolone in the same quarter was determined. Intramammary infusion of endotoxin (.01 mg lipopolysaccharide of E. coli) produced inflammation of the infused quarter, fever, tachycardia, and leukopenia followed by a neutrophilic leukocytosis in the blood and a decrease in plasma zinc and iron concentrations. All corticosteroid treatments, except intramammary administration of prednisolone 4 h after endotoxin infusion, enhanced leukocytosis and diminished local signs of inflammation. Intramuscular injection of dexamethasone or flumethasone together with intramammary infusion of endotoxin and intramammary administration of prednisolone 2 h after lipopolysaccharide infusion completely abolished the febrile response. Abolishment of fever and attenuation of several hematologic and blood biochemical changes may be explained by diminished synthesis of endogenous mediators within the inflamed quarters due to glucocorticosteroid action.

Effect of dexamethasone on experimental Escherichia coli mastitis in the cow

The effect of intramuscular administration of dexamethasone on milk production and on several clinical and hematologic indicators in cows with experimental Escherichia coli mastitis was studied. Two groups of three cows each were intramammarily inoculated with 20 x 10(5) cfu E. coli 0101 K99 F41 in rear quarters. Immediately after inoculation one groups received 30 mg dexamethasone intramuscularly, whereas the other group was injected similarly with pyrogen-free saline. Fourteen days later milk production losses were markedly less in the dexamethasone-treated group. Dexamethasone treatment reduced local clinical signs of inflammation, significantly increased rectal temperatures, and diminished inhibition of rumen amplitude during the acute phase of infection. Moreover, cows treated with dexamethasone showed diminished neutropenia, more pronounced hypozincemia, and delayed onset in the decrease in plasma iron concentrations. Possible mechanisms by which these changes are accomplished are discussed.

Fever, anorexia and forestomach hypomotility in ruminants

Acute febrile diseases are characterized by specific and non-specific symptoms. The non-specific responses include among other signs fever, dullness, anorexia and changes in gastric function. It is the purpose of this review to describe present concepts of fever and the associated reactions produced by bacterial pyrogens and the mechanisms of those reactions. The available data indicate that interleukin-1 is a key mediator of host responses to bacterial infections. However, many questions have not yet been clearly answered. In particular, more detailed studies of the processes within the CNS responsible for anorexia are still required.