Showing papers by "Animal Research Institute published in 1970"
TL;DR: The work indicated that, for the treatment of bovine babesiosis, imidocarb was highly effective in dosages at which no toxicity was observable.
Abstract: Summary The effect of 3, 3’-bis- (2-imidazolin-2-yl)-car- banilide dihydrochloride (imidocarb or 4A65) against Babesia argentinu was evaluated in 47 splenectomised calves and 18 intact steers and its effect against Babesia bigeminu in 19 splenect- omised calves. lmidocarb readily controlled very severe infections with B. argentina at dose rates of 20 mg/kg to 1 mg/kg. B. bigeminu infections were treated successfully with dose rates of 20 mg/kg to 0.4 mg/kg. The drug was effec tive by both subcutaneous and intravenous routes. Signs of toxicity were acute following intra- venous dosages of 20 mg/kg and 10 mg/kg, although the animals survived. Toxic signs were mild or absent for subcutaneous dosages of 10 mg/kg and less. The work indicated that, for the treatment of bovine babesiosis, imidocarb was highly effective in dosages at which no toxicity was observable. The compound completely cured (sterilised) infections with B. argentina in clinically recovered steers treated subcutaneously at dose rates from
46 citations
TL;DR: Results suggest that BYDV does not multiply in its vector M. avenae, and that the virus can accumulate in the gut was demonstrated by the increasing virus concentration in this organ with increasing acquisition access periods.
37 citations
TL;DR: Differences in milk acetylcarnitine and free carnitine are assumed to reflect similar alterations of these compounds in the mammary cell and are discussed in relation to decreased de novo synthesis of fatty acids and increased rate of acetoacetate synthesis which occur in mammary tissue of ketotic cows.
37 citations
TL;DR: The host-specific toxin of Helminthosporium carbonum Ullstrup has a molecular formula approximating C(32)H(50)N(6)O(10) and loss of activity appears to be associated with loss of nitrogen and with decreased solubility in water.
Abstract: The host-specific toxin of Helminthosporium carbonum Ullstrup has a molecular formula approximating C32H50N6O10. The compound has been crystallized and a crystalline hydrochloride derivative has been produced. The molecular weight, as determined by chromatography on Sephadex G-10, is slightly less than 700. The toxin appears to be a cyclic peptide, since, although it does not react with ninhydrin or dinitrofluorobenzene, it yields, on hydrolysis, compounds which react to these reagents. It is unstable in dilute acids, yielding ninhydrin-reacting products. Complete acid hydrolysis yields alanine, proline, and three other ninhydrin-reacting components. The infrared spectrum of the toxin reveals an ester band in addition to amide absorption. Its ultraviolet spectrum reveals the presence of unsaturation in the molecule. The toxin is relatively unstable and loses its specific toxicity. This loss of activity appears to be associated with loss of nitrogen and with decreased solubility in water.
37 citations
TL;DR: The piercing mouthparts of three species of mosquitoes were examined with a stereoscan scanning electron microscope and the stylets of Wyeomyia smithii appear functional despite the belief that this species does not take a blood meal.
Abstract: The piercing mouthparts of three species of mosquitoes were examined with a stereoscan scanning electron microscope. The structures observed are discussed in relation to existing morphological studies. Two pairs of peg-like organs were seen at the tip of the labrum and sensory-like structures measuring approximately 1.2 μ were shown at the tip of the hypopharynx of all species. Differences were observed in the numbers of maxillary teeth of different species. The stylets of Wyeomyia smithii appear functional despite the belief that this species does not take a blood meal.
32 citations
TL;DR: Electron microscopy of sections of intestine and salivary glands of leafhoppers Macrosteles fascifrons (Stal), which had been exposed to clover phyllody-affected plants, revealed the presence of a pleomorphic organism similar to Mycoplasma species.
32 citations
TL;DR: This chapter discusses the endogenous control of estrus and ovulation in sheep, cattle, and swine.
Abstract: Publisher Summary This chapter discusses the endogenous control of estrus and ovulation in sheep, cattle, and swine. For the continuance of the species, sexual receptivity and ovulation are two essential physiological events in the life of the adult female mammal. Of necessity, these events must generally be mutually interrelated and interdependent, and usually occur within a few hours of each other. Among those species regarded as being spontaneous ovulators, the rat and the human have perhaps received most attention; the former as a consequence of its availability in most laboratories, and the latter for obvious reasons. The extent of the basic knowledge, in certain areas of reproduction in domestic species—for example, the sheep—is rapidly catching up with what is known about the rat and the human. This has come about as a consequence of (1) economic pressures to make livestock production more efficient and (2) the realization not only that domestic animals make useful experimental animals, but also that comparative studies can lead to a better understanding of reproductive processes. The terms estrus and onset of estrus have often been loosely used without specifying whether they were being defined in terms of the histological state of the uterus or vagina, or in terms of sexual behavior.
29 citations
29 citations
TL;DR: Direct administration of vitamin E to the lambs completely prevented the occurrence of NMD, and plasma vitamin E concentrations in the treated lambs were significantly higher than in untreated lambs at weekly sampling over a 4-month period regardless of whether the Lambs were born from ewes treated with the vitamin or not.
Abstract: 1. The metabolism of tritium-labelled tocopherol was investigated in thirty-six wethers and forty-two ewes fed on hay known to produce nutritional muscular dystrophy (NMD).2. In one experiment, the effect of selenium or vitamin E or both on the metabolism of tritium-labelled tocopherol was studied. No difference was found in the incorporation rate of radioactivity in tissues due to the addition of either of these components.3. In a second experiment, significantly more radioactivity was found in the tissues of sheep dosed intramuscularly than of those dosed by stomach tube into the rumen. Excretion of radioactivity was rapid when labelled tocopherol was given into the rumen.4. In a third experiment, the efficiency of vitamin E in preventing NMD in lambs was tested. Supplementation with vitamin E of the diet consisting of NMD-producing hay and given to ewes was ineffective as a prophylactic treatment. Direct administration of vitamin E to the lambs completely prevented the occurrence of NMD. Plasma vitamin E concentrations in the treated lambs were significantly higher than in untreated lambs at weekly sampling over a 4-month period regardless of whether the lambs were born from ewes treated with the vitamin or not.
26 citations
TL;DR: Except when cultures were well aerated by shaking, Marasmius oreades (Bolt.) Fr.
Abstract: Except when cultures were well aerated by shaking,Marasmius oreades (Bolt.) Fr., the fairy ring mushroom, was able to utilize, in pure culture studies, fractions of humus from sources as divergent as the A horizon of a chernozemic soil and the Bh horizon of a Podzol. The importance of this ability to soil infestation was discussed and it was suggested that improved soil aeration be studied as a control measure.
26 citations
TL;DR: The intravenous infusion of solutions of ammonium salts into sheep produced a toxic condition in which the clinical signs, pathological findings and concentrations of ammonia in the venous blood were comparable with those found in urea poisoning, provided that the urea and ammonia toxicoses were induced over similar time intervals.
Abstract: The intravenous (i.v.) infusion of solutions of ammonium salts into sheep produced a toxic condition in which the clinical signs, pathological findings and concentrations of ammonia in the venous blood were comparable with those found in urea poisoning, provided that the urea and ammonia toxicoses were induced over similar time intervals. Our results indicate that urea toxicosis in ruminants is due to the toxic effects of ammonia. Although the clinical signs resulting from the i.v. infusion of ammonium chloride, acetate and hydroxide showed some relationship to the basicity of the compounds, alkalosis did not appear to be a necessary prerequisite for ammonia toxicosis.The tolerances of sheep to orally administered urea and i.v. infused ammonium salt solutionswere shown to be positively related to dietary nitrogen intake. These results and the observations reported by Payne & Morris (1969) that the concentrations of urea-cycle enzymes per unit of liver tissue were markedly affected by dietary nitrogen intake suggest that supplementation of ruminants grazing low-protein pastures with urea, occurs at a time when their tolerances to an over-dose of urea are minimal.The i.v. administration of arginine and of y-amino butyric acid plus glucose did not appear to be of practical value in preventing urea poisoning.
TL;DR: A state of non-equilibration of isotope exists for the acetyl-CoA and acetylcarnitine, citrate, malate, aspartate, glutamate and α-ketoglutarate pools distributed between cytoplasmic and mitochondrial compartments.
Abstract: Specific radioactivity curves of citrate, malate, glutamate and aspartate were measured in vivo in liver from normal, fat-fed and diabetic rats with [1-14C]acetate as precursor at time intervals of 0.1 to 20 min. A mathematical model of 14 pools and 40 interconnecting flux rates been constructed and by computer analysis on the Univac 1108 flux rates and intra- and extra-mitochondrial metabolite pool distribution calculated from the measured specific radioactivity curves. Flux rates and pool distributions were varied by using an automatic minimization routine to minimize the difference between observed and theoretical values until an acceptable fit of computer generated specific radioactivity time curves to experimentally observed specific radioactivities was obtained. Steady state kinetics were assumed, i.e. the model was fixed with no change in pool sizes over the measured time interval. The main conclusions were:
1
A state of non-equilibration of isotope exists for the acetyl-CoA and acetylcarnitine, citrate, malate, aspartate, glutamate and α-ketoglutarate pools distributed between cytoplasmic and mitochondrial compartments.
2
Cytoplasmic pools of citrate, acetyl-CoA and acetylcarnitine account for the slow rate of radioactivity decay observed for these metabolites in vivo.
3
Key flux rates were acetate entry into the citrate cycle of 0.36, 0.28 and 1.05 μmoles × min−1× g liver−1 in normal, fat-fed and diabetic rats. Citrate turnover rates were 1.21, 0.37 and 1.94 μmoles × min−1× g liver−1 for normal, fat-fed and diabetic rats. The acetate pool was 0.23 μmoles/g liver in normal, 0.44 μmoles/g liver in fat-fed and 0.38 μmoles/g liver in diabetic rats. Metabolite pool distribution was greater in the extra- than intramitochondrial space: the shift was most marked in the diabetic rat where the intra- to extramitochondrial malate distribution was in the ratio of 1:21.5.
TL;DR: High levels of vitamin A were administered daily to 8 kittens for 4 or 5 weeks after weaning, and they were destroyed after a further 6 to 15 weeks, and at necropsy most of the long bones were considerably shorter than those of litter mate controls and some showed abnormal morphology.
TL;DR: An adaptation of a widely used colorimetric procedure for the determination of hydrogen sulfide is reported to provide an improved method for unpurified biological materials and much less material is required for purified materials.
TL;DR: Mitochondria from rat heart, liver, and skeletal muscle, when isolated in a medium containing 10 mM EDTA, showed poor respiratory control and large volume changes in the presence of ATP or oxidizable substrates and may involve the same mechanism that brings about reversal of swelling.
Abstract: Mitochondria from rat heart, liver, and skeletal muscle, when isolated in a medium containing 10 mM EDTA, showed poor respiratory control and large volume changes in the presence of ATP or oxidizable substrates. Swelling required the presence of alkali metal cations and permeant anions and probably reflects ion transport. As shown previously for skeletal muscle mitochondria, addition of Mg2+ prevents major volume changes and also imposes control of respiration by phosphorylation. Addition of Mg2+ after ATP-energized swelling caused shrinkage of the mitochondria back to the original state. This reversal of swelling is energized by ATP, but not by substrate (when ATP synthesis is inhibited by oligomycin). Electron micrographs showed that the matrix space of mitochondria from all three sources expands during the swelling process. In addition, cristal membranes showed several three-dimensional arrangements. In the contracted state which existed in presence of ATP+Mg2+, cristae of muscle mitochondria appeared “sheetlike”, whereas in presence of substrates many of these cristae assumed a “tubular” appearance. The structural changes in liver mitochondria under these conditions appeared similar to those of muscle mitochondria, but because of the greater proportion of matrix in liver mitochondria, the terms “sheetlike” and “tubular” are less descriptive of the situation. A transition from tubular to sheetlike appearance occurred upon addition of either ATP or ADP to respiring mitochondria in presence of added substrates and phosphate. This transition required Mg2+ and may involve the same mechanism that brings about reversal ofswelling. The implications of these studies are discussed in relation to proposed mechanisms of odixative phosphorylation.
TL;DR: The results of these experiments suggest that tissues of the male leafhopper are less susceptible to CPrCA infection than are those of the female, and this hypothesis is fact it would explain the difference in transmission between the sexes.
Abstract: The ability of aster leafhoppers, Macrosteles fascifrons (Stal), to transmit clover proliferation causal agent (CPrCA) to aster, Callistephus chinensis Nees, plants depends on the sex and age of the insects at the time they are allowed to feed on infected plants. When adult leafhoppers were given acquisition access feeds for various times, transmission by females increased from 14% after a 3-day feed to 34% after a 21-day feed. With males, no transmission occurred after feeds of 3 and 7 days, and only 5% transmitted CPrCA after a 21-day feed. When nymphs were given acquisition access feeds of 7 days, 20% of the females and 11% of the males subsequently transmitted the causal agent. Prolonging the acquisition access period to 14 days increased the transmission by females (39%) but not by the males (12%). Injection of adult insects with inocula containing CPrCA resulted in 27% of the females but only 3% of the males becoming infective.
CPrCA could be recovered, using infectivity bioassays, from the alimentary canals of both male and female leafhoppers at various times after they had been exposed to diseased plants. CPrCA was first recovered from the alimentary canals of both male and female leafhoppers at day 14 after the start of a 7-day acquisition access feed. In males the relative concentration of causal agent decreased by day 21 and then remained at about the same level. In females, the concentration increased sharply by day 21 and then decreased by day 28. Increase in concentration of CPrCA in the alimentary canal suggests that the causal agent multiplies in this organ in both male and female leafhoppers but to a lesser extent in the males.
The results of these experiments suggest that tissues of the male leafhopper are less susceptible to CPrCA infection than are those of the female. If this hypothesis is fact it would explain the difference in transmission between the sexes.
TL;DR: A procedure has been devised for preserving mitochondrial function for prolonged periods of time by freezing rat liver mitochondria in a solution containing dimethyl sulfoxide and bovine plasma albumin and storing at liquid nitrogen temperature.
Abstract: A procedure has been devised for preserving mitochondrial function for prolonged periods of time. Rat liver mitochondria in a solution containing dimethyl sulfoxide and bovine plasma albumin are frozen and stored at liquid nitrogen temperature. Phosphorylation efficiency, respiratory control, and Mg2+ control of energized swelling are preserved by this method.
TL;DR: Pepsin is inactivated quickly by high pH when diluted with hard water at ambient temperatures in the cheese plant, explaining occasional problems in coagulating milk as discussed by the authors, but the results showed that rennet was relatively stable under these conditions.
TL;DR: Improvements to the polyacrylamide disc electrophoretic technique for the characterization of bacterial dehydrogenases are reported and gels without nonspecific background diformazan deposit were obtained.
TL;DR: In this article, the fatty acid uptake of bovine spermatozoa has been investigated, showing that myristic acid is the major component in the diglycerides.
TL;DR: Thiamine supplementation had no effect on the onset of nervous signs or on growth rate and milk replacer intake and plasma glucose, lactate, pyruvate, and magnesium appeared generally unrelated to the drug effects.
TL;DR: Certain fatty acids in the C(5) to C(18) range, at concentrations as low as 10(-5) M, were found to inhibit the germinations of spores of the sensitive fern, Onoclea sensibilis L, and the addition of Pteridium aquilinum (L.) Kuhn, containing antheridogen A, was found to overcome this inhibition.
Abstract: Certain fatty acids in the C(5) to C(18) range, at concentrations as low as 10(-5) M, were found to inhibit the germinations of spores of the sensitive fern, Onoclea sensibilis L. The addition of gametophytic culture flltrates of the bracken fern, Pteridium aquilinum (L.) Kuhn, containing antheridogen A, was found to overcome this inhibition and allow the spores to germinate and the gametophytes to develop in a normal fashion. Some fatty acids were found to increase the antheridium-inducing potency of antheridogen A as much as 10-fold. An effect similar to this may promote the diecious reproduction of ferns.