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The effect of temperature and mobile phase composition (methanol-water) on the retention behaviour of an oligomeric series of n-octylsilyl bonded phases in reversed-phase liquid chromatography has been investigated. Plots of lnk against 1/T (van't Hoff plot) and the enthalpy of transfer (ΔHo) yields linear relationships under the conditions studied. The ΔHo values of the aromatic hydrocarbons and n-alkyl benzoates are higher than those of the polar compounds due to their higher level of interaction with the stationary phase. A linear plot of ΔHo vs. ΔSo suggest that the retention process, which is essentially controlled by non-specific (dispersive) interactions between the solutes and the bonded ligands, is identical for all cases evaluated. The existence of similar retention mechanisms is confirmed by the constant value of the enthalpy-entropy compensation temperature of the columns for a given class of componds. As expected, decreasing the methanol content (% v/v) of the mobile phase results in increased eluite retention times. The methylene and phenyl selectivities are found to be independent of the carbon content of the stationary phases and varied only with the eluent composition. In addition to their high stability under aggressive mobile phase conditions as previously reported, the results of this study generally showed that the solute retention process on oligomeric phases are similar to those exhibited by the conventional reversed phases.

The purity of alkylnitrile compounds has been investigated using gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). The investigation was carried out to supplement earlier reported work using the alkylnitrile compounds, hexanenitrile and valeronitrile, as mobile phase additives in HPLC. GC impurity profiling and GC-MS experiments showed the presence of low level nitrogenous impurities in the alkylnitrile compounds. Analytical interrogation and chemical isolation were employed to identify the impurities as alkylamines. Tri-n-butylamine (TBA) and di-n-pentylamine (DPA) impurities were found in batches of hexanenitrile and valeronitrile respectively and it was found that it was the amine impurities, at very low levels, which caused the observed chromatographic improvements for basic solutes when using the alkylnitrile compounds as mobile phase additives in reversed-phase HPLC. The amines themselves were subsequently used at extrem...

Thermogravimetric analysis of silica gel has shown that the loss in weight between 30° and 910°C can be quantitatively explained on the basis of water being lost from three distinct and different populations of sites on the silica gel surface. The results indicate that the site energies of the three different populations are randomly distributed and, consequently, the resulting weight loss steps from each population can be described by the integral of a simple normal distribution with temperature. The calculated weight loss obtained by assuming three different site-groups having randomly distributed adsorption energies is, within experimental error, coincident with the experimental data. It is also shown that the water evolved from the second population of sites originates from strongly bound water and may also contain water generated by the condensation of (geminal) silanol groups contained in the overlapping and neighbouring population.

The application of thermal and spectroscopic techniques in the characterisation of chemically modified materials is illustrated with several examples: ethylene vinyl acetate (EVA) copolymers which had been hydrolysed under alkaline conditions, amosite asbestos fibres which had been reacted with alkyldimethylchlorosilanes, and a polymeric composite material which had been affected by moisture.

The mechanism of mitochondrial extrusion from reticulocytes was studied in whole blood from dogs made anemic by treatment with phenylhydrazine hydrochloride. The initial stage of preparation for mitochondrial extrusion was attraction of vesicles to mitochondria. There was subsequent encirclement of the organelle and other bodies, such as ferritin, by coalesced vesicles forming double membrane-limited vacuoles. Large vacuoles were formed from the union of single vacuoles, and they were usually situated near the periphery of the cell. Fusion of the outer membrane of vacuoles with the plasmalemma of the reticulocyte provided a route for exposure and release of mitochondria and other material to an extracellular location. An extracellular mitochondrion, therefore, was confined by its original double membrane, and a third membrane was derived from the internal boundary of vacuoles.

The use of oligomeric synthesis for the preparation of reverse phases by a fluidized bed technique is described. Reverse phases comprising of one to ten oligomers were synthesized and the physical and chromatographic properties of each phase examined and the results reported. the nature of the interactions were investigated by measuring the excess free enthalpies of absorption of a homologous series of aromatic hydrocarbons and aromatic esters from retention measurements taken at different temperatures. It is shown that a reverse phase comprising at least five oligomers behaves as a true dispersive phase, has consistent and predictable retentive properties and is far more stable to acid conditions than the normal type of reverse phase.

The separation of enantiomers by gas chromatography has been investigated on a fused silica capillary column coated with octakis(3-O-trifluoroacetyl-2, 6-di-O-n-pentyl)-γ-cyclodextrin. The objective of this work is to propose possible mechanisms for the stereoselectivity of this stationary phase by rationalising the observed behaviour of relatively simple structurally-related compounds (alcohols and some of their fluoroacyl derivatives), characterising the cyclodextrin derivative and carrying out suitable molecular modeling experiments. Recent work on developing methods to characterise the stationary phase will be presented.

A previous study using intrapleural administration of surface-modified amosite asbestos showed a difference in the number of pleural mesotheliomas induced with C18-hydrocarbon derivatised fibres compared to native amosite asbestos. The study has been repeated with larger groups of animals (30) under specific pathogen free conditions, resulting in an increase in the mean animal survival time for both fibre-treated groups. Under these conditions there was no significant difference between the numbers of pleural mesotheliomas induced by C18 hydrocarbon-modified amosite asbestos and native amosite asbestos. The major difference between the two studies was the mean time to death from tumour of rats exposed to fibres. The C18 amosite treated rats in the first study may not have had a mean survival time long enough to allow mesotheliomas to develop.

Mobile phase additives, e.g., cyclodextrins and ion-pairing reagents, have been used for the specialist separation of enantiomers and ionic species. In this paper, the use of an additive for mediating the retention characteristics of general solutes on a reversed-phase is described. A C4 aliphatic compound, valeronitrile, has been investigated as a potential mobile phase additive in base solvents consisting of methanol–water mixtures. A range of test solutes have been chromatographed at various levels of valeronitrile concentration on a commercial C8 bonded reversed-phase, and their retention characteristics compared. The results obtained show that relatively small amounts of valeronitrile can cause a significant change in retention, and further, can significantly improve the chromatography of basic compounds.

Twelve Florida native wethers were given ammonium metavandate, calcium orthovanadate and calcium pyrovanadate by capsule in a study to examine the toxicity of the compounds. The initial daily dosage of 100 mg elemental vanadium was increased by 50 mg at 2-d intervals for an assessment not only of the toxic effects, but also to determined the amount that caused a decline in feed intake to 25% of that of control animals. The initial decline in feed intake was observed at 400 to 500 mg vanadium/d (9.6 to 12 mg/kg body weight, 310 to 350 ppm); a rapid decline in feed intake was accompanied by diarrhea. One sheep fed 550 mg vanadium as calcium orthovanadate died 3 d after dosing. One animal on each of the other three treatments was killed and necropsied for immediate comparison. Extensive mucosal hemorrhage of the small intestine and diffuse or petechial subcapsular hemorrhages of the kidneys were observed for sheep fed all compounds. The three vanadium compounds appeared to be similar in toxicity, as determined by abrupt declines in feed intake and pathological changes of the intestine and kidney. For a determination of acute toxicosis, three sheep were given 40 mg/kg body weight of vanadium as NH4VO3 in gelatin capsules and two sheep were included as controls. Two of the treated animals died within 80 h after administration and the other three were killed at 96 h. Vanadium content of kidney, liver, bone, spleen, lung and muscle was elevated by treatment.

The typical crescent and holly leaf forms of sickled erythrocytes from white-tailed deer were examined by transmission electron microscopy. These cellular aberrations were induced in those animals which are homozygous for the β3-chain and are reversibly related to elevations of pH and POO2. The internal structure of the typically sickled cell was organized into polymerized aggregates. At very high magnification, cross-sections of the cells revealed microtubules, with a diameter of 160-190 Å, which were compared to those which have been described in human sickle cells. The tubules beneath the plasmalemma or extending into protruding spicules were more or less parallel and oriented in a single direction, whereas the aggregates in the remainder of the cell cytoplasm were randomly dispersed. In view of the association of the sickling of deer erythrocytes with a specific hemoglobin β-chain and the marked similarity of the internal architecture of these cells to human sickle cells, the deer erythrocytes provide a model for hemoglobin polymerization which may lead to insights that are applicable to the human condition.

The matchstick cell is a unique form of sickled deer erythrocytes which is related to a specific β2-chain type in the white-tailed deer. Like the typical crescent form of sickled cell, it is an in vitro phenomenon which is induced by high pH and POO2 and reverses to the usual discoid form with deoxygenation and lowering of the pH. Transmission electron microscopy revealed a precise intracellular structure with polymerization of the hemoglobin into long filaments which were aligned in one axis of the cell, so that they appeared as long rods at relatively low magnification. A second feature, which contrasts to typical sickle forms of deer or man, is an absence of any type of microtubular structure. This suggests a different mode of intermolecular bonding related to primary structural variations of the β-chains which are associated with the matchstick cells and with typical sickle cells. Elucidation of the various structural differences between these β-chains may give additional clues to the mechanism of hemoglobin aggregation in the human sickle cell.

The effects of hydralazine on aortic rupture, hemodynamics and aortic ultrastructure were studied in turkeys fed B-aminopropionitrile (BAPN). A mortality rate of 24% due to hemopericardium and internal hemorrhage in turkeys fed only BAPN increased to 91% when turkeys were fed both BAPN and hydralazine, despite a significant reduction in blood pressure after both drugs. Death rates among turkeys fed BAPN and hydralazine were lowered by adding either dietary propranolol (53%), which lowered blood pressure and dP/dt max, or reserpine (67%), which reduced blood pressure and increased dP/dt max. Striking ultrastructural alterations of collagenous and elastic fibers of the aortic media, which were additive to the effects of BAPN alone, were induced by BAPN and hydralazine. This study demonstrates that a 6-week feeding of high levels of BAPN and hydralazine, which accumulates in vessel walls, can produce vascular injury and increase mortality from hemorrhage in lathyritic turkeys.

Two experiments were conducted with day-old Broad Breasted white turkey male poults to determine whether wet litter and supplemental biotin would influence the severity of foot pad dermatitis. Poults grown on wet litter had a significantly increased incidence of foot pad dermatitis. The addition of biotin to the corn-soy diet resulted in a decreased severity of foot pad dermatitis in poults maintained on dry litter; however, it did not influence the severity of the lesions when poults were maintained on wet litter. Histological examination of the foot pad tissue indicated that poults which received the control diet were deficient in biotin.

This paper describes a novel process for the production of chemically bonded phases using fluidised bed technology. Hitherto fluidisation of particles with the size range below 50 µm was considered impossible. In this study, particles with sizes as small as 7 µm have been successfully fluidised and subsequently reacted to produce bonded phases. The operating parameters of the fluidised bed system have been studied and their effect on the chromatographic properties of the products have been investigated. Advantages of the process are thein situ removal of fines, high batch to batch repeatability andin situ chemical post-treatments (end-capping).

Modern systems consist of 3 units: gas chromatography, mass spectrometry and data systems. The authors consider the operation of the 3 units independently and show the power of the combined system and its modes of operation.

Two experiments were conducted with aged laying hens to determine the influence of feeding 5,000 p.p.m. of iodine as potassium iodine (KI) and/or injecting 12 mg. of estradiol upon fat accumulation in the liver and serum cholesterol levels. The KI was fed for 8 days before making liver and blood determinations, and the estradiol was injected 3 days prior to making the determinations. The feeding of KI or injection of estradiol resulted in significantly increased liver weight. When the two treatments were combined a further significant increase in liver weights was obtained. The percent of fat in the liver was significantly increased by the injection of estradiol. However, the feeding of KI in the presence or absence of estradiol did not affect the percentage of fat in the liver. Neither of the treatments significantly affected the fatty acid composition of the liver fat. Feeding of KI or injection of estradiol significantly increased total serum cholesterol levels. When the two treatments were combined a further increase in serum cholesterol level was observed. Histological changes of the livers of hens treated with KI and estradiol were similar to those previously described for the "fatty liver syndrome."

The desorption–adsorption coefficients and distribution coefficients of a series of aliphatic alcohols, carboxylic acids and aldehydes between water and ODS2 reverse phase have been determined using a chromatographic procedure. The moderator concentrations over which the measurements were made were kept at sufficiently low levels so that moderator/moderator interactions in the mobile phase and moderator interactions with adsorbed moderator were kept minimal.It is shown that the desorption–adsorption coefficients decrease and the distribution coefficients between water and the reverse phase increase exponentially with the carbon number of the moderator confirming the system can be described by the Martin equation. As a result, substances having chains of five carbon atoms or more could produce complete coverage of the surface when present at a level of only a few percent in the mobile phase. Thus, the surface of the reverse phase can be strongly modified without significantly affecting the solvent characteristics of the mobile phase. It was shown that dispersive interactions between the reverse phase and the hydrocarbon chain of the moderator were the same for each moderator and from the slope of the log K against carbon-number curves, it was also shown that the logarithmic increment for each methylene group in the alkyl chain was the same for all moderators and independent of the functional group. The difference in the distribution coefficients between different moderators having alkyl chains of the same length depends solely on the dispersive interactions between the functional groups with the reverse phase and the functional group with any residual silanol groups that may be present. The method used can also determine the effective chromatographic surface area of a given reverse-phase column. It is suggested that the technique could also be used to determine the effective surface area of different types of bonded phases, give a measure of the residual polarity of the stationary phase and the magnitude of the interactive capacity of the hydrocarbon portion.

In High Voltage Capillary Zone Electrophoresis a field is applied across a narrow bore capillary filled with electrolyte solution. An electroendosmotic (EEO) flow is generated within this capillary which sweeps solutes along the tube. An absolute method of flow estimation is described, along with some operating parameter effects on the solute mobility. System parameters enabling flow direction reversal and a zero flow are described. The use of several capillaries simultaneously and the effect of pH on EEO flow rates are also shown. Effects of various operating parameters on solute resolution are also detailed.

SummaryA high vitamin D intake 1, 500,000 units/kg of diet) severely decreased weight gain, caused necrosis and calcification of blood vessels and kidneys, and decreased the suspension stability of the blood of rats. Chondroitin sulfate A and the flavonoids (rutin and hesperidin) showed no effect on weight loss, serum cholesterol, tissue calcifications, or hematocrits, but returned the suspension stability of the blood towards normal.

Methoxylated flavonoids containing one or three to seven methoxyl groups were compared for inhibitory activity on erythrocyte aggregation in vitro. A serial erythrocyte sedimentation procedure was used, in which the compounds are incubated in blood maintained in thermal and flow equilibria. All compounds tested (30 µmol/liter) significantly inhibited erythrocyte aggregation: hesperidin < tri-O-methylapigenin < tetra-O-methylscutellarein < tangeretin < heptamethoxyflavone < nobiletin < sinensetin. The most active compound, sinensetin, contained methoxyl groups at the 3',4',5,6,7 positions. Compounds with fewer methoxyl groups were significantly less active (P < 0.01), as were compounds with additional methoxyl groups at the 3 and 8 positions. On a molar basis, compounds containing five to seven methoxyl groups were several fold more active on erythrocyte aggregation than was low-molecular-weight dextran.

A high incidence of foot pad lesions and breast blisters were observed in broilers. Histological examination of foot pads indicated changes similar to those previously found when broilers were fed a biotin deficient diet. It is suggested that a marginal biotin deficiency in practical diets may be responsible for enlarged foot pads causing birds to rest on their breast resulting in increased breast blisters.

Visceral leishmaniasis was diagnosed in a dog which had been in Spain for 4 years before being brought to Florida. A bone marrow aspirate from the dog was examined by electron microscopy. Phagocytized amastigotes by macrophages had an electron-dense plasma membrane and contained ribosomes, rough endoplasmic reticulum, a well-developed Golgi apparatus, an intracellular flagellum, lipid, a kinetoplast, a row of microtubules immediately beneath the cell membrane, and a nucleus with marginated chromatin. Mean diameter and microtubule number of the dog isolate were similar to those reported for Leishmania donovani amastigotes of human origin. Plasma cells were congregated in the vicinity of parasitized macrophages.

The erythrocytes of 2 cats experimentally infected with Cytauxzoon felis were examined by light and electron microscopy. In stained blood smears, parasitized erythrocytes usually contained a single, roundish organism, but occasionally up to 4 were present in a cell. Chains of these roundish organisms also were seen. Elongated parasites, sometimes with ear-like projections, were present in a few erythrocytes. By electron microscopy, the parasite contained a poorly defined nucleus, rough endoplasmic reticulum, ribosomes, nonplicated mitochondria, food vacuoles, and a cytostome on its limiting membrane. Usually, the parasite was oval, but budding forms also were evident. Crystalloid inclusions were present in parasitized and nonparasitized erythrocytes.

Tumors of the breast musculature of 4 chickens with Marek's disease were examined by light and electron microscopy. By light microscopy, tumors were composed of lymphoid cells which had infiltrated and separated bundles of muscle fibers. By electron microscopy, there was margination of chromatin and duplication of the inner nuclear membrane in almost all neoplastic cells of breast tumors of all 4 chickens. In addition, in one chicken the nuclei of tumor cells contained naked herpesvirus-like particles.

The effects of feeding dietary cadmium (83 micrograms/g of diet) to young pigs on the distributions of copper, iron, and zinc in urine samples and in kidney, liver, and muscle tissues was determined. The diet with added Cd resulted in renal and hepatic tissue concentrations of 42.90 +/- 10.57 micrograms/g and 7.90 +/- 2.37 micrograms/g, respectively, at the 40th day of the experiment. Iron was found to decrease at the same time, which predisposed to the anemic condition of these pigs. The feeding of dietary CD to pigs prevented extensive fatty hepatocytic infiltration and severe jaundice, but not hydropic degeneration induced by aflatoxin B1. Cadmium increased the toxicity of warfarin with severe lameness, subcutaneous hematomas in the ventral surface of the neck, and death.

The morphologic features of Anaplasma marginale were determined after treatment of infected calves with oxytetracycline. By light microscopy, anaplasma bodies in erythrocytes of treated calves were enlarged and vacuolated, small and dense, or comma shaped. Several degenerated forms of anaplasma bodies were observed by electron microscopy. There was a blending of the 2 membranes surrounding initial bodies, aggregation of nucleoprotein at the periphery of the subunit, and vacuolation. A 2nd form of degeneration was coalescence of subunits in marginal bodies. A 3rd form of degeneration was unification of subunits of anaplasma bodies and clumping of nucleoprotein. A 4th form of degeneration was the persistence of an anaplasma body as a solitary, irregularly shaped mass containing electron-opaque clumps.

Equine protozoal myeloencephalitis (EPM) was diagnosed in 10 horses. By electron microscopy, schizonts were found in intact host cells of the spinal cords or, more frequently, free in the extracellular spaces. Developmental stages of schizonts differed morphologically, and the late stage of schizogony was characterized by endopolygeny. These findings permitted tentative identification of the protozoon as a Sarcocystis sp. Free merozoites were present in the extracellular spaces or in cells of the spinal cord. Pericytes of capillaries were most frequently parasitized by merozoites were present in the extracellular spaces or in cells of te spinal cord. Pericytes of capillaries were most frequently parasitized by merozoites, but the cytoplasm of neurons, macrophages, intravascular and tissue neutrophils, and axons of myelinated nerve fibers also contained these organisms. The presence of parasites in the cytoplasm of tissue and circulating neutrophils suggest that this putative Sarcocystis sp. may have a hematogenous phase of infection.

The light and electron microscopies of Tetrameres columbicola gravid females in sections of the parasitized proventriculus of pigeons were studied. By light microscopy, the most conspicuous structures in the sectioned parasite were the intestine, ovary, and especially the uterus that contained numerous eggs. By electron microscopy, there was a thick mat of pigment-coated microvilli on the surfaces of the intestinal epithelial cells. The germinal zone of the ovary contained nonmembrane-bound oocytes, but oocytes were confined by a membrane in the growth zone of the ovary. The core of the spermatheca contained oocytes and the periphery harbored sperm. In this location, the unfertilized oocyte had pseudopods; sperm had invaginations of the plasma membrane. After fertilization, there was proliferation of ribosomes within the oocyte. Embryonating eggs in the uterus had thick shells and were partially enveloped by elongations of the uterine epithelial cells. Surfaces of the epithelial cells were pleated and they had electron opaque areas at the points of the pleats. Larvae in eggs had a well developed annulated cuticle and muscular layer. Somatic muscle cells had tailed appendages that protruded into the pseudocoelom. The single layer of cells beneath the hypodermis had lateral processes at the base of the cells that interdigitated with similarly elongated processes of adjacent muscle cells. Striated fibers were present in the central portion of the cells.

Twelve Florida native wethers were given ammonium metavandate, calcium orthovanadate and calcium pyrovanadate by capsule in a study to examine the toxicity of the compounds. The initial daily dosage of 100 mg elemental vanadium was increased by 50 mg at 2-d intervals for an assessment not only of the toxic effects, but also to determined the amount that caused a decline in feed intake to 25% of that of control animals. The initial decline in feed intake was observed at 400 to 500 mg vanadium/d (9.6 to 12 mg/kg body weight, 310 to 350 ppm); a rapid decline in feed intake was accompanied by diarrhea. One sheep fed 550 mg vanadium as calcium orthovanadate died 3 d after dosing. One animal on each of the other three treatments was killed and necropsied for immediate comparison. Extensive mucosal hemorrhage of the small intestine and diffuse or petechial subcapsular hemorrhages of the kidneys were observed for sheep fed all compounds. The three vanadium compounds appeared to be similar in toxicity, as determined by abrupt declines in feed intake and pathological changes of the intestine and kidney. For a determination of acute toxicosis, three sheep were given 40 mg/kg body weight of vanadium as NH4VO3 in gelatin capsules and two sheep were included as controls. Two of the treated animals died within 80 h after administration and the other three were killed at 96 h. Vanadium content of kidney, liver, bone, spleen, lung and muscle was elevated by treatment.

Ten laying hens with low plasma cholesterol levels and no signs of fatty liver syndrome were examined at necropsy. Liver coloration and deposition of body fat were not abnormal in such hens. Eleven nonlaying hens had signs of fatty liver syndrome. They were out of production for 1 to 3 months and had elevate plasma cholesterol levels. At necropsy, such hens had yellow livers, heavy deposits of body fat, and several involuted egg yolks, which were dark yellow. Intimal plaques were observed by light microscopy in the abdominal aortas of hens with low plasma cholesterol levels; the plaques contained little or no lipid and were composed of three or four rows of modified smooth-muscle cells. Aortic intimal plaques of hens with high plasma cholesterol levels were composed of 16 to 18 rows of modified smooth-muscle cells when examined by light microscopy. The plaques contained intracellular and extracellular lipid, indicating aortic atherosclerosis. Electron-microscopic observations of the abdominal aortas of both groups of hens were similar to light-microscopic observations, except that lipid, including cholesterol clefts, was seen both intracellularly and extracellularly in the thickened tunica intima of hens with high plasma cholesterol values. Thus, the presence of aortic atherosclerosis was confirmed by electron microscopy. It is suggested that the endogenous hypercholesterolemia and cessation of egg production, characteristic of severe fatty liver syndrome, originated from the reabsorption of involuted egg yolks and that such reabsorption caused the development of aortic atherosclerosis and deposition of excess body fat.

A malignant giant cell tumor of bone in a cat is described. Numerous C-type particles were found budding from the neoplastic cells. Viruses have not previously been associated with malignant bone noeplasms in cats.