Pharmacokinetics of orally administered pirfenidone in male and female beagles.

Pirfenidone, a promising antifibrotic agent, was administered orally to dogs at 0, 40, 140, and 400 mg/kg/day. Serum was collected for pirfenidone assay at 0, 26 and 39 weeks of treatment. From the pirfenidone concentrations, pharmacokinetic parameters were determined for each dog at each treatment interval. The only significant differences because of gender were for concentration maxima. Unsurprisingly, there were many significant differences because of dose in concentration maximum and area under curve (AUC), and significant, positive linear correlations of both parameters with dose. There were few significant differences in time of maximal concentration and no correlation with dose. The mean +/- SE clearances were 1.99 +/- 0.13, 1.64 +/- 0.13 and 1.78 +/- 0.14 L/h/kg for doses of 40, 140, and 400 mg/kg, respectively, with no significant differences attributable to dose. There was an unexplained pattern in maximal concentration and AUC with regard to duration of treatment, with the parameters being highest at week 0, lowest at week 26, and intermediate at week 39. Clearance had the reverse pattern; time of maximal concentration had no pattern.

Mixed ruminal microbes of cattle produce isopropanol in the presence of acetone but not 3-D-hydroxybutyrate.

The objective was to evaluate the ability of mixed rumen microbes to synthesize isopropanol from acetone or 3-D-hydroxybutyrate. Rumen fluid from seven mature, nonpregnant, dry Holstein cows was incubated with starch or cellulose and additions of acetone, 3-D-hydroxybutyrate, or saline. Rumen fluid was analyzed for isopropanol after 0, 3, 6, and 9 h. No isopropanol was present in any sample at 0 h, and none was present in incubations containing saline or 3-D-hydroxybutyrate at any subsequent time. Incubations that included acetone produced small amounts of isopropanol from 0 to 3 and 3 to 6 h and significantly larger amounts from 6 to 9 h. With starch as the energy substrate, production from 6 to 9 h was 3.8 micromol/min per liter of rumen fluid and 3.7 micromol/min per liter with cellulose as the energy substrate; however, these values did not differ significantly. Mixed rumen microbes could synthesize isopropanol from acetone but not from 3-D-hydroxybutyrate, and rumen microbial metabolism of acetone was the likely source of plasma isopropanol seen in ketotic ruminants.

Effects of estrogen on whole animal and tissue glucose use in female and male rainbow trout.

Reports of changes in carbohydrate metabolism during vitellogenesis in fish prompted an investigation of the effects of estrogen on glucose utilization in rainbow trout. Estrogen pellets were implanted in both female and male fish, and a third group of male fish was given a sham operation. After cannulation of the dorsal aorta, D-[1-3H]glucose and 2-deoxy-D-[U-14C]glucose were injected into the fish to observe whole animal and tissue glucose use. We found that estrogen does not affect glucose turnover rate or transit time but causes a decrease in plasma glucose concentration and size of the glucose mixing pool. Adipose tissue in female fish utilized glucose at a higher rate than sham fish. Ovarian tissue used more glucose per kilogram of body weight than the testes of the male fish. Regardless of treatment, brain had the highest rate of glucose consumption per gram of tissue, followed by gonads and red blood cells. Muscle and adipose tissue utilized only small amounts (< 1 nmol.g tissue-1.min-1) of glucose. We conclude that an increase in the rate of whole body glucose use is not responsible for the fall in plasma glucose caused by estrogen and seen during vitellogenesis.

Role of eicosanoids in abortion and its prevention by treatment with flunixin meglumine in cows during the first trimester of pregnancy.

Intravenous infusion of E. coli endotoxin at a rate of 4.16 ng/kg/min over 6 hr (total dose 1.5 micrograms/kg) in 5 cows in the first trimester of gestation induced abortion between 60 and 72 hr in three cows. Plasma PGF2 alpha levels in the aborting cows increased significantly to 289% of the zero time control (ZTC) at 1 hr and remained elevated for 9 hr. The PGF2 alpha level remained unaffected in the non-aborting cows except at 2 hr. The plasma TxB2 levels were increased by 6 to 18 fold for 6 hr in both the aborting and non-aborting cows relative to their ZTC controls. The 6-keto-PGF1 alpha levels were significantly increased to 2 to 3 fold only in the aborting cows. Plasma cortisol levels were increased maximally to 1,500% of ZTC at 5 hr in the aborting cows. Thereafter, the levels gradually declined but remained significantly elevated for 24 hr. The increases in the cortisol levels in the non-aborting cows were only 280% of ZTC at 5 hr and returned to ZTC value by 12 hr. Plasma progesterone levels in the aborting cows remained unaffected until 12 hr followed by a progressive decline through 18 hr to extremely low levels at 3, 4, and 5 days. Endotoxin-infusion caused hyperglycemia in both aborting and non-aborting cows and lactic acidemia in the aborting cows. Treatment with two doses of flunixin meglumine (FM, 1.1 mg/kg), an inhibitor of cyclooxygenase, 1 hr prior to endotoxin infusion and then 13 hr later, completely prevented the endotoxin-induced abortion and increases in the plasma PGF2 alpha, TxB2 and 6-keto-PGF1 alpha concentrations. The PGE level remained unaffected. Although FM treatment failed to abolish endotoxin-induced increases in the plasma cortisol and lactic acid levels, it effectively prevented marked decreases in the progesterone and increases in the glucose concentrations. It was concluded that the use of FM offers therapeutic promise in preventing bovine abortion caused by endotoxin resulting from bacterial infection during the 1st trimester of gestation.

Effects of endotoxin infusion on circulating levels of eicosanoids, progesterone, cortisol, glucose and lactic acid, and abortion in pregnant cows.

The effects of Escherichia coli endotoxin infusions (1.0 or 2.5 micrograms kg-1 over 6 h) on pregnancy were investigated in cows in the first, second and third trimester of gestation. Endotoxin increased the plasma levels of prostaglandins (PGs), thromboxane B2 and cortisol, and decreased progesterone. The severity of the clinical signs and the magnitude of the increases in plasma PGs, thromboxane B2 and cortisol tended to depend on the dose of endotoxin, but were independent of the gestation period. There was hyperglycemia followed by hypoglycemia and lactic acidemia. Hyperglycemia and lactic acidemia were significant only at the high dose of endotoxin. Endotoxin infusion at both doses caused a preferential mobilization of oleic acid from adipose tissue, and also had some effects on the mobilization of palmitic and stearic acids during the post-infusion period. The cows in the first trimester of gestation were more sensitive to the abortifacient effect of endotoxin than cows in the second and third trimester of gestation. The results of this study indicate that the mechanism of endotoxin-induced abortion in cows initially involves a prolonged release of PGF2 alpha and its subsequent stimulant effect on uterine smooth muscle contraction and luteolytic effect leading to a gradual decline in the plasma levels of progesterone. It was concluded that pregnancy terminates in the absence of an adequate level of progesterone, especially during the first trimester of gestation, when progesterone of extraluteal origin is not yet available, coupled with the PGF2 alpha-induced propulsive contraction of the uterus. In addition, the metabolic and circulatory failures in severe cases of endotoxemia, especially at the high dose of endotoxin, resulting either directly or indirectly via the release of various autacoids, catecholamines and cortisol, may also contribute to the termination of pregnancy at any stage of gestation.

Effects of smooth and rough Pasteurella haemolytica lipopolysaccharides on plasma cyclic-nucleotides and free fatty acids in calves.

The present study examined the potency of smooth or rough Pasteurella haemolytica lipopolysaccharide infusion (LPS, 24 ng kg-1 min-1 for 500 min) on plasma cyclic-nucleotides and several free fatty acids (FFA) in calves. Both smooth or rough LPS increased plasma cAMP immediately to its maximum at 1 h of infusion, whereas plasma cGMP levels rose slowly and peaked 12 h later. The increases in cAMP levels were more prolonged for smooth LPS than rough LPS. The maximum plasma cAMP rise coincided with increases of several plasma FFA. Rough LPS increased plasma oleic greater than palmitic greater than stearic greater than linoleic acids in the second hour and reached their steady state levels between 2 h of infusion and 5 h post-infusion. Thereafter, oleic acid remained maximally elevated, while stearic acid decreased and other FFA returned to baseline. Smooth LPS had no effects on palmitic and stearic acids, but elevated oleic acid in an essentially similar manner to rough LPS and increased linoleic acid initially at 5 h, followed by decreases throughout post-infusion. These results demonstrate that endotoxemia produces early marked elevations in plasma cAMP, a gradual rise in plasma cGMP and disproportionate increases in several plasma FFA. The data also demonstrate that smooth and rough LPS differ in their abilities to increase plasma cAMP and FFA and these may be attributed to differences in their in vivo mechanisms of action. The study suggests that cAMP and cGMP may mediate actions of endotoxin at the cellular level and that differences exist in release and/or utilization of each FFA at different stages of endotoxemia.

Fatty infiltration of liver in spontaneously ketotic dairy cows.

The purpose of this study was to ascertain 1) fatty infiltration of the liver in spontaneously ketotic cows and 2) the most appropriate blood components to aid diagnosis of ketotic fatty liver. Liver biopsies and blood samples were obtained under field conditions. Cows were divided into three groups (healthy, mildly ketotic, and severely ketotic) by their blood ketone body concentrations. Severely ketotic cows had a greater percent fat in the liver than healthy cows. The mildly ketotic group fell between the other two groups and was significantly different from only the severely ketotic group. There was a positive correlation between fatty infiltration and blood ketone body concentrations but a negative correlation with glucose concentrations. Liver-specific enzymes were positively correlated with fatty infiltration. Only ornithine carbamoyltransferase and iditol (sorbitol) dehydrogenase could be used to separate healthy cows from those with severe ketosis. The best equation to explain the variation of percent fat in liver included concentration of beta-hydroxybutyrate (BHB) and logarithm of ornithine carbamoyltransferase concentration (Log-OCT): % Fat = -6.15 + 2.39 (BHB) + 11.7 (LogOCT) Although this equation explained 39.5% of the variation, it could not be used to predict reliably percent fat in the liver. Liver biopsy seems still to be the only reliable method of measuring of fatty infiltration in the liver.

Ectopic calcification in lambs from feeding the plant Cestrum diurnum.

Hypercalcemia and ectopic calcification were induced in 5 lambs by supplementing the diet with the dried leaves of the plant Cestrum diurnum, for 8 to 9 weeks. Lambs developed mineralization of blood vessels, heart, kidneys, and lungs. These tissues were examined by light and electron microscopy. In the vascular tissue there was calcification of elastic fibers in the hyperplastic intima and the media, along with mineralization of mitochondria of aortic smooth muscle cells. Myocardial cells and their mitochondria were mineralized. In the kidney, there was calcification of the epithelium of the distal convoluted tubules and collecting tubules, Bowman's capsule, and the mesangial cells of the glomeruli. In the lung, there was mineralization of the alveolar septal walls and the bronchi and bronchioles. Feeding of the calcinogenic plant to lambs caused extensive soft tissue calcification. Results of the study indicated that degeneration was the early soft tissue lesion in this plant toxicity.