The participation of soluble factors in the omega-oxidation of fatty acids in the liver of the sheep.

The removal of soluble components from an ovine hepatic microsomal preparation decreased the omega-hydroxylation of dodecanoic and hexadecanoic acids. The results suggest that one or more soluble components play a role in the microsomal omega-hydroxylation of fatty acids. The possible roles in the reaction of catalase (known to stimulate the microsomal desaturations of fatty acids and alkylglycerols) and superoxide dismutase were investigated. The addition of these enzymes to the complete (but not the washed) microsomal preparation stimulated both the initial omega-hydroxylation reaction and the subsequent dehydrogenation reactions of the omega-oxidation pathway. The similarity of the effects of catalase and superoxide dismutase and stimulation of two different steps of the omega-oxidation pathway suggest that these agents are acting indirectly by removing active oxygen species rather than directly on the enzymes of microsomal fatty acid omega-hydroxylation.

Primary suprasellar germ cell tumor in a dog.

A 5-year-old female Rottweiler was examined because of a history of progressive CNS depression and apparent blindness. Findings included retinal degeneration and cranial nerve deficits as well as pronounced hypercholesterolemia and bradycardia. At necropsy, a 3-cm soft, tan mass was found on the ventral surface of the rostral portion of the brain, encompassing the hypophysis and filling the sella tursica. Histologic examination of tumor sections identified 3 distinct cell types. The location and histologic features of the solitary tumor were most consistent with classification as a primary intracranial germ cell tumor.

Chinaberry poisoning in two dogs.

Two young dogs became acutely ill following ingestion of fallen fruit from a chinaberry tree (Melia azedarach). Clinical signs of poisoning developed within hours and were characteristic of gastrointestinal and CNS disturbances. Despite prompt and aggressive emergency treatment, neither dog survived longer than 36 hours after the onset of clinical signs of poisoning. Necropsy of 1 dog revealed severe renal congestion, moderate hepatic congestion, and a moderate amount of serosanguineous fluid in the abdominal cavity. To the best of our knowledge, previous reports of chinaberry poisoning of dogs are lacking. However, chinaberry poisoning is well documented in human beings and other animals. Therefore, we strongly recommend that dogs, in addition to other animals, have restricted access to chinaberry trees and their fruit to prevent potential poisoning.

Malignant hyperthermia-like reaction secondary to ingestion of hops in five dogs.

Five dogs, 4 of which were Greyhounds, suffered adverse effects secondary to the ingestion of spent hops. Mean time to onset of clinical signs was 3 hours, and clinical signs included marked hyperthermia, restlessness, panting, vomiting, signs of abdominal pain, and seizures. Four of the 5 dogs died despite aggressive therapeutic measures, and there was rapid onset of rigor mortis in 3. The overrepresentation of Greyhounds, coupled with the clinical signs, was suggestive of a malignant hyperthermia-like response to the ingestion of hops. It also is possible that hops contain an uncoupler of oxidative phosphorylation.

Fate of dietary perchlorate in lactating dairy cows: Relevance to animal health and levels in the milk supply.

Perchlorate is a goitrogenic anion that competitively inhibits the sodium iodide transporter and has been detected in forages and in commercial milk throughout the U.S. The fate of perchlorate and its effect on animal health were studied in lactating cows, ruminally infused with perchlorate for 5 weeks. Milk perchlorate levels were highly correlated with perchlorate intake, but milk iodine was unaffected, and there were no demonstrable health effects. We provide evidence that up to 80% of dietary perchlorate was metabolized, most likely in the rumen, which would provide cattle with a degree of refractoriness to perchlorate. Data presented are important for assessing the environmental impact on perchlorate concentrations in milk and potential for relevance to human health.

The effect of dietary methyl branched-chain fatty acids on aspects of hepatic lipid metabolism in the rat.

1. Rats were fed to appetite on a stock laboratory diet or on diets consisting of the stock diet and in addition 50 or 200 g triolein/kg, 50 g palmitic acid/kg or 50 g/kg of a concentrate mixture of methyl branched-chain fatty acids (Me-BCFA) which had been prepared from sheep adipose triacylglycerols. 2. No differences could be detected in the delta 9-desaturase activity or fatty acid synthetase activity of liver preparations from rats which had been fed on either the stock diet, the 50 g palmitic acid/kg or the 50 and 200 g triolein/kg diet; the palmitic acid diet was therefore taken as the control diet in subsequent experiments. 3. Rats consuming the 50 g Me-BCFA/kg diet exhibited a marked reduction in the capacity of their liver microsomes for delta 9-desaturation when compared with animals receiving the control diet. The delta 6-desaturase activity also showed an inhibitory trend with the Me-BCFA diet. 4. Microsomal omega-oxidation of fatty acids, mitochondrial succinate oxidation and the activity of cytosolic fatty acid synthetase (FAS) were unaffected by the ingestion of the Me-BCFA mixture compared with the diet which included palmitic acid. 5. There were no differences in the plasma concentration of thyroxin, insulin and glucagon between animals fed on the diets containing palmitic acid or the Me-BCFA. 6. For a given concentration of fatty acids the Me-BCFA had a greater inhibitory effect when added to incubations of liver microsomes from rats fed on the standard diet than did the addition of palmitic acid. 7. The observations in vivo and in vitro strongly suggested that the Me-BCFA were having a specific inhibitory effect on the desaturation reaction.

The effects of physiological state and plane of nutrition on the concentrations of microsomal cytochromes and the omega-oxidation of fatty acids in various tissues of the sheep (Ovis aries).

The omega-oxidation activities and electron transport components of the microsomal fractions of tissues from pregnant, non-pregnant and lactating sheep on different planes of nutrition have been examined. Differences from the rat system were found, and between the non-pregnant and late pregnant sheep. The hepatic microsomal activity of omega-oxidation was approximately doubled by fasting for 5 days, but was unaltered by pregnancy or lactation per se. This increase was not caused by an increase in the specific activity of the omega-hydroxy fatty acid dehydrogenases. The results are discussed in relation to the glucose stresses of pregnancy in ruminants.

Characterization of the bovine innate immune response to intramammary infection with Klebsiella pneumoniae.

Gram-negative bacteria are responsible for almost one-half of the clinical cases of mastitis that occur annually. Of those gram-negative bacteria that induce mastitis, Klebsiella pneumoniae remains one of the most prevalent. Detection of infectious pathogens and the induction of a proinflammatory response are critical components of host innate immunity. The objective of the current study was to characterize several elements of the bovine innate immune response to intramammary infection with Klebsiella pneumoniae. The inflammatory cytokine response and changes in the levels of soluble CD14 (sCD14) and lipopolysaccharide (LPS)-binding protein (LBP), 2 proteins that contribute to host recognition of gram-negative bacteria, were studied. The contralateral quarters of 7 late-lactating Holstein cows were challenged with either saline or K. pneumoniae, and milk and blood samples were collected. Initial increases in the chemoattractants C5a and IL-8, as well as TNF-alpha, were evident in infected quarters within 16 h of challenge and were temporally coincident with increases in milk somatic cells. Augmented levels of TNF-alpha and IL-8 were observed in infected quarters until >48 h postchallenge, respectively. Elevated levels of IL-12, IFN-gamma, and the antiinflammatory cytokine, IL-10, which were first detected between 12 and 20 h postinfection, persisted in infected quarters throughout the study (>96 h). Initial increases in milk LBP and sCD14 were detected 16 and 20 h, respectively, after challenge. Together, these data demonstrate that intramammary infection with K. pneumoniae elicits a host response characterized by the induction of proinflammatory cytokines and elevation of accessory molecules involved in LPS recognition.

Do patients with moderately impaired gastrointestinal function requiring enteral nutrition need a predigested nitrogen source? A prospective crossover controlled clinical trial.

This prospective double blind randomised seven day crossover controlled clinical trial was carried out to determine whether enterally fed patients with moderately impaired gastrointestinal function require a predigested nitrogen (N) source compared with whole protein. Twelve malnourished patients with varying gastrointestinal abnormalities, who required enteral feeding, received 2.25 l of one of two isocaloric isonitrogenous enteral diets (1 kcal/ml, 4.8 g nitrogen/l) containing either predominantly medium chain peptides (tetra or higher peptides) or whole protein as the nitrogen source. Nitrogen absorption and balance were calculated from dietary intake and analysis of 24 hour total urinary and faecal nitrogen for the last five days of each study period. There was no significant difference in either stool weight (110 (SEM) (49) v 111 (32) g/d), nitrogen absorption (91 (2) v 89 (2)%) or nitrogen balance (+1.0 (1.3) v +0.6 (1.4) g nitrogen/d) between the peptide and whole protein nitrogen sources when all patients are considered. There was, however, evidence to suggest a nutritional advantage from administering an enteral diet whose nitrogen source comprises oligopeptides, rather than whole protein, to a subgroup of patients with small bowel disease.