Joule heating calculations in capillary zone electrophoresis. Reply to "Recalculation of the temperature inside capillaries using high buffer concentrations" by Zhang et al.
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Buffers↗
Biomedical subjects
R F Cross
Publications and source records attributed to R F Cross.
Comparison of silver-ion high-performance liquid chromatographic quantification of free and methylated conjugated linoleic acids.
Silver-ion high-performance liquid chromatography was used to fractionate a mixture of conjugated linoleic acid (CLA) isomers (as the free fatty acids, CLAFFA) in commercial CLA mixtures and biological samples. Due to the unchanged retention mechanism, it was assumed that the elution order of the isomers remained the same as that of methyl esters separated on the same column. The most abundant isomers, cis/trans 10, 12-18:2 and cis/trans 9,11-18:2, were separated better as free acids on a single column than in the methyl ester form. Quantification of the CLA standard was used as the reference profile to evaluate different methylation methods commonly used to prepare CLA methyl esters for quantitation. Acid-and base-catalyzed derivatization methods resulted in CLA intraisomerization and losses in total conjugated dienes content. Acid (HCl and BF3) methylations significantly elevated the level of trans,trans isomers and significantly reduced the cis/trans isomers. Base methylation, tetramethylguanidine/methanol, resulted in loss of trans,trans isomers, and a substantial loss of total underivatized conjugated dienes. Other catalysts such as the trimethylsilyldiazomethane produced additional peaks of unidentified artifacts. The analysis of CLAFFA appears to provide more accurate quantification of CLA isomers in commercial and biological samples.
Adipose Tissue↗
Salt effects in capillary zone electrophoresis. IV. Resolution versus time and the effect of potassium phosphate and its concentration in the high ionic strength separation of sulphonamides.
The effects of potassium phosphate buffer and its concentration upon the capillary zone electrophoretic separation of 23 sulphonamides and a neutral marker were examined at pH 7. The resolution between the pairs was improved with the increased concentration of the buffer from 65 mM to 174 mM. Nineteen sulphonamides, a hydrolysis product and several unidentified minor components were baseline resolved in both 101 and 138 mM phosphate buffers. In 174 mM buffer all 21 ionised sulphonamides and the other compounds were separated. A simple relationship between the resolution of analyte pairs (Rs) and the square root of the mean analysis time for the pair (square root of tapp) was derived, but few of the pairs displayed this behaviour. For the majority of pairs of compounds, Joule heating appeared to cause a maximum in the Rs versus square root of tapp relationship, while non-ideality and shifts in ionisation with increasing salt concentration appeared dominant in other cases.
Buffers↗
Dietary conjugated linoleic acids increase lean tissue and decrease fat deposition in growing pigs.
Conjugated linoleic acids (CLA) decrease the body fat content of rodents; the aim of this study was to determine whether dietary CLA altered carcass composition of pigs. Female Large White x Landrace pigs (n = 66) were used in this study. To obtain initial body composition, six pigs were slaughtered at 57 kg live weight, whereas the remaining pigs were allocated to one of six dietary treatments (0, 1.25, 2.5, 5.0, 7.5 and 10.0 g/kg CLA, containing 55% of CLA isomers). The diets, containing 14.3 MJ digestible energy (DE) and 9. 3 g available lysine per kg, were fed ad libitum for 8 wk. Dietary CLA had no significant effect on average daily gain (861 vs. 911 g/d for pigs fed diets with and without CLA, P = 0.15) or feed intake (2. 83 vs. 2.80 kg/d, P = 0.74). The gain to feed ratio was increased by dietary CLA by 6.3% (0.328 vs. 0.348, P = 0.009). Fat deposition decreased linearly (-8.2 +/- 2.09 g/d for each gram per kilogram increase in CLA concentration; P < 0.001) with increasing inclusion of CLA. At the highest level of CLA inclusion, fat deposition was decreased by 88 g/d (-31%). Similarly, the ratio of fat to lean tissue deposition decreased linearly (-0.093 +/- 0.0216 for each gram per kilogram increase in CLA concentration; P < 0.001) with increasing dietary CLA. The carcass lean tissue deposition response to dietary CLA was quadratic in nature and was maximized (+25%) at 5. 0 g/kg dietary CLA. Overall, dietary CLA increased the gain to feed ratio and lean tissue deposition and decreased fat deposition in finisher pigs.
Adipose Tissue↗
Chromatographic separation of fluorescent thiol adducts of 4-chloro-7-sulphobenzofurazan. Use as substrates for enzymes of the mercapturic acid xenobiotic pathway.
Fluorescent adducts of 4-chloro-7-sulphobenzofurazan with cysteine, cysteinylglycine, reduced glutathione and N-acetylcysteine were prepared. Adducts were separated by HPLC on a 3-mm Nova-Pak C18 reversed-phase column using isocratic elution with a solvent of acetonitrile-0.15 M phosphoric acid (5:95) buffered at pH 2.5. The adducts were detected using a fluorescence detector set at an excitation wavelength of 365 nm and an emission wavelength of 510 nm and an ultraviolet detector at 254 nm. The adduct of reduced glutathione was also formed by the action of the enzyme glutathione-S-transferase. This adduct acted as a substrate for the enzyme gamma-glutamyltranspeptidase and the product of this reaction, the 4-chloro-7-sulphobenzofurazanyl derivative of cysteinylglycine, acted as a substrate for either dipeptidase or aminopeptidase M. The sequential enzymic effects could be detected by changes in the relative fluorescence intensity of the solutions to which the respective enzymes had been added but were more appropriately followed by changes in the HPLC elution profiles after enzymic treatment of solutions.
Acetylcysteine↗
The supercritical fluid extraction of polar drugs (sulphonamides) from inert matrices and meat animal products.
The objective of this study was to examine the extension of supercritical fluid extraction (SFE) to the extraction of polar drugs. The ultimate aim was to extract veterinary residues from food animal products and thereby demonstrate the versatility of SFE. This technique is shown to have many facets that require careful thought and understanding if it is to be successfully used. Our initial studies indicate that polar drugs may be readily solubilized from relatively inert matrices such as sand, with high recoveries and very little discrimination between related compounds while using only moderate extraction conditions and times. SFE of the same drugs from spiked chicken liver and swine muscle is significantly more difficult and requires more drastic conditions. Close to complete recoveries are achieved for some drugs, while considerably less is found in the worst case. For sulphamerazine, sulphamethizole, sulphamethazine, sulphamethoxypyridazine, sulphamethoxazole, and the major metabolite N4-acetyl-sulphamethoxazole, the recoveries are 97, 66, 94, 79, 53, and 65%, respectively, from spiked liver and 95, 27, 86, 91, 96 and 70%, respectively, from spiked swine muscle. Incurred sulphamethazine is recovered from swine muscle in good general agreement with the reference values provided.
Animals↗
Serial propagation of porcine group C rotavirus (pararotavirus) in a continuous cell line and characterization of the passaged virus.
The Cowden strain of porcine group C rotavirus (pararotavirus) was adapted to serial passage in a continuous monkey kidney cell line (MA104). Key factors in its successful adaptation included use of virus passaged in primary porcine kidney cells as the initial inoculum, use of roller tubes, and addition of pancreatin to the maintenance medium. A cell culture immunofluorescence test was used to quantitate the virus at each passage level, since a possible cytopathic effect was obscured by the effects of pancreatin. The virus titers dropped after initial passage into MA104 cells but increased thereafter, with peak titers evident after 16 passages (10(7) immunofluorescence U/ml). Immune electron microscopy and genome electropherotyping were used to identify group C rotavirus particles and confirm group C rotavirus double-stranded RNA gel migration patterns, respectively, from infected cell culture supernatants. The electropherotype of the cell culture-propagated group C rotavirus was identical to that of the gut virulent virus from which it was derived. The cell culture-passaged group C rotavirus also retained its infectivity for gnotobiotic pigs. No group A rotavirus was detected in the intestinal contents of the pigs or in cell culture fluids from group C rotavirus-inoculated monolayers with the two former techniques or the cell culture immunofluorescence test. This is the first verified report of serial propagation of a non-group A rotavirus in a continuous cell line.
Animals↗
Effect of age, weaning and postweaning diet on small intestinal growth and jejunal morphology in young swine.
The effect of age, weaning and postweaning diet on small intestinal growth and morphology were investigated in young swine. Small intestine weight and villus height, measured at the midpoint of the small intestine (i.e., jejunum), were determined in suckling and weaned pigs. Scanning electron microscopy was performed on jejunal specimens from suckling pigs killed at 2, 10, 21, 28 and 35 d of age and in 21-d and 35-d weaned pigs at various ages postweaning. A 2 X 2 factorial arrangement of postweaning diets also was used to investigate jejunal morphological measurements in a 21-d-old weanling pig group. These dietary treatments evaluated the effects of 0 or 25% added dried whey and 0 or 6% added corn oil. The morphology results demonstrated that jejunal villus height declined during the suckling period, with a marked reduction at 3 and 7 d postweaning for both 21-d-old and 35-d-old weaned pigs. Transmission electron microscopy also demonstrated long, uniform microvilli on the jejunal villi in suckling pigs at 2 and 21 d, with markedly reduced lengths upon weaning. Jejunal villi were shorter in weaned compared with suckling pigs at the same approximate chronological age. Scanning electron microscopy in suckling pigs at 2 and 10 d of age demonstrated long, thin, fingerlike villi with subsequently reduced heights and larger diameters by 35 d of age. At weaning, villi were in close apposition, resulting in an overall smoother villus luminal surface. Villus height subsequently increased by 14 d postweaning, coinciding with the appearance of morphologically tongue-shaped villi. Starter diet composition initially did not influence the villus height reduction response postweaning. Dietary corn oil addition was subsequently associated with shortened villus length (P less than .05) during the starter phase.
Aging↗
Etiology of ammoniated hay toxicosis.
Some animals consuming hay treated with anhydrous ammonia have developed neurological signs including hyperexcitability, circling and convulsions. A series of experiments was conducted to identify tentatively the toxin and determine its mode of action. Three out of four sheep fed ammoniated orchardgrass hay (approximately 4% ammonia on a dry basis) developed convulsions. Two of the three sheep died within 18 h of the onset of signs. The concentrations of blood lactate and pyruvate were elevated in the symptomatic sheep (P less than .05). A proposed toxin, 4-methyl imidazole, did not induce the syndrome when 750 mg/d (approximately 10 times the dietary amount) were administered orally. Four out of five calves that received milk from cows fed ammoniated oat hay (approximately 5% ammonia on dry basis) displayed hyperexcitability and circling. Concentrations of blood lactate and pyruvate were also elevated in the calves. The crude alkaloid fraction of the toxic milk produced neurological signs similar to those of the calves when injected into mice. A fluorescent compound was found in the alkaloid fraction of toxic milk and ammoniated hay, but not in control milk or untreated hay. The fluorescent compound was quite labile; hence, characterization has been unsuccessful thus far.
Ammonia↗
A rapid staining technic for cryptosporidia.
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Animals↗
Porcine pararotavirus: detection, differentiation from rotavirus, and pathogenesis in gnotobiotic pigs.
Some characteristics of a newly recognized porcine enteric virus are described. Tentatively, the virus was referred to as porcine pararotavirus (PaRV) because it resembled rotaviruses in respect to size, morphology, and tropism for villous enterocytes of the small intestine. However, it was antigenically distinct from porcine, human, and bovine rotaviruses and reoviruses 1, 2, and 3, and the electrophoretic migration pattern of PaRV double-stranded RNA was distinct from the electrophoretic migration patterns of the rotaviral and reoviral genomes. By passage in gnotobiotic pigs, PaRV was isolated from two suckling diarrheic pigs originating from two herds. After oral exposure of gnotobiotic pigs, villous enterocytes of the small intestines became infected as judged by immunofluorescence, resulting in villous atrophy and diarrhea. Mortality was high when gnotobiotic pigs less than 5 days old were infected. The C strain of this virus was serially passed 10 times in gnotobiotic pigs, and electron microscopy, immunofluorescence, and serological tests indicated no extraneous agents. The virus was serially passed five times in cell cultures which contained pancreatin in the medium, but replication was negligible or absent, as the number of immunofluorescent cells decreased with each passage. Since rotaviral infections are frequently diagnosed by direct electron microscopy of fecal specimens, the presence of other morphologically similar viruses, such as PaRV, should be considered. The use of immune electron microscopy is suggested as a means of helping recognize this situation.
Animals↗
Oral administration of zinc sulfate for control of ovine foot rot.
Zinc sulfate (ZnSO4) was added to the diet of adult ewes and lambs with contagious foot rot for periods of 4 weeks to 6 months and to the diet of lambs for 5 weeks before experimental exposure to foot rot. Intake averaged between 0.5 and 0.75 g/animal/day. A beneficial effect was demonstrated when lambs with foot rot were fed ZnSO4 and were maintained under dry conditions, but when conditions were wet, ZnSO4 did not reduce the number of infections or prevent new infections. When ZnSO4 was fed before exposure, the infection rate of medicated lambs in a wet environment was almost twice that of unmedicated lambs in the same pen.
Administration, Oral↗
Zinc sulfate foot bath for control of ovine foot rot.
A 10% zinc sulfate (ZnSO4) solution was used as a foot bath to control foot rot in pastured lambs. When the foot bath was placed where infected lambs would walk through it each day, clinical evidence of foot rot was greatly reduced within 15 days, and the total number of cases detected after thorough foot trimming was greatly reduced within 30 days. When the foot bath was placed under the salt feeding box, it was not effective. Feeding ZnSO4 at the rate of 0.5 to 0.75 g/head/day was not effective in controlling foot rot. Temperature and moisture conditions were favorable for foot rot transmission throughout the trials.
Administration, Topical↗
Rotavirus-like, calicivirus-like, and 23-nm virus-like particles associated with diarrhea in young pigs.
Virus particles morphologically similar to caliciviruses and rotaviruses were detected by electron microscopy (EM) in the intestinal contents of a 27-day-old diarrheic nursing pig. A third small spherical 23-nm virus-like particle was also observed. Calicivirus-like particles averaged 33 nm in diameter. Similar to rotaviruses, rotavirus-like particles were present as single-capsid 55-nm forms or double-capsid 70-nm particles. Most gnotobiotic pigs orally exposed to samples containing these three viruses developed diarrhea and villous atrophy of the small intestine, and all shed the three viruses in their intestinal contents. Attempts to propagate these viruses in cell culture were unsuccessful. The antigenic relationship of the rotavirus-like particles to known rotaviruses was explored by immune EM and immunofluorescent staining. By these techniques, the rotavirus-like particles did not cross-react with antisera to porcine, bovine, or human rotaviruses or to reovirus type 3. Antisera from gnotobiotic pigs exposed to all three viruses had enzyme-linked immunosorbent assay and virus neutralization titers of <4 against porcine rotavirus. Previous infection of gnotobiotic pigs with the mixture containing rotavirus-like particles failed to protect them against a subsequent challenge with porcine rotavirus. The antigenic relationship of the calicivirus-like particles to known caliciviruses was investigated by immune EM and virus neutralization. By these tests, the calicivirus-like particles did not react with antisera against feline calicivirus strain 255 or M-8. In a study conducted at Plum Island Animal Disease Center, antiserum against the three combined agents did not specifically neutralize any serotype of swine vesicular exanthema virus.
Animals↗
Influence of environmental factors on transmission of ovine contagious foot rot.
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Animals↗
Response of sheep to various topical, oral, and parenteral treatments for foot rot.
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Administration, Oral↗
Rotavirus as a cause of diarrhea in pigs.
A rotavirus (reovirus-like agent) was associated with diarrheal diseases occurring in 1- to 4-week-old suckling pigs in 8 herds and in weaned pigs in 2 herds. Transmissible gastroenteritis virus was also detected in 2 of these herds, as was enteropathogenic Escherichia coli in 5 herds. Morbidity was generally greater than 80% in pigs of the affected age group within these herds, and mortality from diarrhea ranged from 7 to 20%. The disease due to rotavirus in suckling pigs appeared similar to the syndrome commonly referred to as milk scours, white scours, or 3-week scours. Diarrhea and villous atrophy, resembling that seen in transmissible gastroenteritis, occurred in naturally infected pigs and in gnotobiotic pigs experimentally infected with rotavirus. Diagnosis was accomplished by immune electron microscopy of intestinal contents and by immunofluorescent staining of enterocytes. A massive infection of enterocytes with rotavirus was demonstrated by immunofluorescence, which helps explain the pathogenesis of this disease. The apparent rarity of clinical rotaviral infections in suckling pigs greater than 7 days old is probably due to the acquisition of passive immunity from immune sows.
Animals↗
Pathogenesis of porcine rotaviral infection in experimentally inoculated gnotobiotic pigs.
Porcine rotavirus was shown to infect gnotobiotic pigs and induce an acute enteric disease clinically characterized by diarrhea, anorexia, depression, and occasional vomition. Onset of clinical signs correlated closely with the appearance of lesions within the small intestinal mucosa, and recovery from infection was associated with the regeneration of normal, functional villous epithelium. Villous atrophy, especially in the caudal two-thirds of the small intestine, was the consistent lesion observed in pigs with clinical signs of rotaviral infection. Villi were often short, blunt, and covered with cuboidal epithelial cells. Immunofluorescent microscopy methods demonstrated that the principal site of rotaviral replication was the villous columnar epithelial cells in the small intestine.
Animals↗