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Biomedical subjects

J E Bauer

Publications and source records attributed to J E Bauer.

At least 55 records · Page 3Linked to original sources
PubMed1990

Increased serum and liver lipid mass and hepatic 3-hydroxy-3-methylglutaryl CoA reductase activities in rabbits fed soy protein saturated fat diets.

Male New Zealand white rabbits were pair-fed high fat, soy protein-dextrose diets containing either hydrogenated coconut oil (HC) or safflower oil (SA) for 155 days. A third group was fed a low fat, soy protein-dextrose-corn oil diet (SD) previously shown to be normocholesterolemic in the rabbit. All animals gained similar amounts of weight during the feeding period. The HC group became significantly hypercholesterolemic after 28 days with peak elevations at 58 days. Although some adaptation in the response occurred thereafter, serum cholesterol concentrations remained significantly elevated. Serum triglyceride concentrations were similarly elevated in this group. Rabbits fed either the SD or SA diets remained normocholesterolemic. At the end of the feeding period significant elevations of serum total phospholipid and phosphatidyl inositol concentrations were seen in the HC group. Elevations of all other phospholipid classes were also observed but were not statistically significant. Lipid analysis of HC livers revealed significant elevations of free and esterified cholesterol and hepatic microsomal HMG-CoA reductase activities. Increased serum and hepatic cholesterol and sterol biosynthesis in rabbits can thus be induced solely as a result of dietary coconut oil. The elevation of certain serum phospholipids may reflect tissue changes and is consistent with either increased biosynthesis or the impairment of phospholipase activities. Whether dietary fatty acids can affect cell signaling through inhibition of phospholipid turnover remains to be elucidated.

Animals↗
PubMed1990

Serum lipid and lipoprotein changes in ponies with experimentally induced liver disease.

Alterations in serum lipid and lipoprotein concentrations in ponies with experimentally induced liver disease were investigated. Hepatocellular damage was induced, using a nonlethal dose of carbon tetrachloride. In a separate group of ponies, obstructive jaundice was induced by surgical ligation of the common bile duct. Over a 6-day period, blood samples were obtained from ponies after treatment with carbon tetrachloride and for 12 days in ponies subjected to surgery. Serum cholesterol and triglyceride concentrations were unaffected in both groups of ponies, except for significantly (P less than 0.01) high triglyceride concentration in ponies of the ligated group during the second postsurgical week. This increase was most likely attributable to anorexia observed during that period. Hyperbilirubinemia was observed early in ponies of the ligated group; most of the bilirubin was of the conjugated type. Using electrophoretic and ultracentrifugal methods, serum lipoprotein alterations were detected only in ponies of the ligated group. Increases of very low-density and low-density lipoprotein cholesterol concentrations and decrease in high-density lipoprotein cholesterol concentration were found. Although no changes were seen in total serum cholesterol concentration, a redistribution of lipoprotein cholesterol was observed in ponies of the ligated group. Similar alterations in lipoprotein distribution have been found in dogs, rats, and human beings with obstructive jaundice and cholestasis. The association between serum lecithin:cholesterol acyl transferase activities and these lipoprotein alterations remains to be elucidated.

Animals↗
PubMed1989

Nutritional management of hepatic disease.

The successful management of hepatic diseases of dogs and cats requires an understanding of hepatic metabolism and nutritional processes. General aspects of dietary therapy for hepatic diseases are described, along with specific recommendations for the promotion of tissue regeneration. Special considerations, including the role of diet in encephalopathy, hepatic lipidosis, and copper-associated hepatic toxicosis, are also discussed.

Animals↗
PubMed1989

Serum biochemical indicators of liver function in neonatal foals.

Serum biochemical indicators of liver function were determined in healthy, age-matched foals during the first 270 days of life. Values were compared with those of healthy adult horses and with those determined on the day of birth (less than 12 hours old). Serum alkaline phosphatase, gamma-glutamyl transferase, and L-iditol dehydrogenase activities were increased during the first 2 weeks of life. Serum cholesterol, triglyceride, and total and unconjugated bilirubin concentrations peaked during this same period. During the early neonatal period (less than 12 hours old), globulin concentrations (mainly beta 2 and gamma fractions) were low and albumin/globulin ratios were high. However, individual values for all analytes were varied.

Alkaline Phosphatase↗
PubMed1988

Effects of co-occurring aromatic hydrocarbons on degradation of individual polycyclic aromatic hydrocarbons in marine sediment slurries.

Rates of polycyclic aromatic hydrocarbon (PAH) degradation and mineralization were influenced by preexposure to alternate PAHs and a monoaromatic hydrocarbon at relatively high (100 ppm) concentrations in organic-rich aerobic marine sediments. Prior exposure to three PAHs and benzene resulted in enhanced [14C]naphthalene mineralization, while [14C]anthracene mineralization was stimulated only by benzene and anthracene preexposure. Preexposure of sediment slurries to phenanthrene stimulated the initial degradation of anthracene. Prior exposure to naphthalene stimulated the initial degradation of phenanthrene but had no effect on either the initial degradation or mineralization of anthracene. For those compounds which stimulated [14C]anthracene or [14C]naphthalene mineralization, longer preexposures (2 weeks) to alternative aromatic hydrocarbons resulted in an even greater stimulation response. Enrichment with individual PAHs followed by subsequent incubation with one or two PAHs showed no alteration in degradation patterns due to the simultaneous presence of PAHs. The evidence suggests that exposure of marine sediments to a particular PAH or benzene results in the enhanced ability of these sediments to subsequently degrade that PAH as well as certain other PAHs. The enhanced degradation of a particular PAH after sediments have been exposed to it may result from the selection and proliferation of specific microbial populations capable of degrading it. The enhanced degradation of other PAHs after exposure to a single PAH suggests that the populations selected have either broad specificity for PAHs, common pathways of PAH degradation, or both.

Adaptation, Physiological↗
PubMed1988

Substrate specificity studies of partially purified rabbit heart lipoprotein lipase.

Rabbit heart lipoprotein lipase (LPL) was partially purified by affinity chromatography. The purified enzyme was characterized by salt inhibition, the requirement of a serum co-factor and an alkaline pH optimum. Because of the known hypocholesterolemic effect of dietary polyunsaturated fat in this and other species, the fatty acyl substrate specificity of this lipase was also studied. Both saturated and unsaturated fatty acid chain hydrolysis were investigated using synacyl and mixed acyl triglyceride emulsion substrates. It was found that trans, monounsaturated and some saturated fatty acids were more favorably hydrolyzed than polyunsaturated cis fatty acids. Positional specificity was also observed. The physiological significance of these findings may relate to a) the production of lipoprotein remnant particles relatively enriched in polyunsaturated fatty acids, especially when consumed in the diet and b) the subsequent preferential delivery of these fatty acids to the liver.

Animals↗
PubMed1988

Lipids, lipoproteins and hepatic 3-hydroxy-3-methylglutaryl CoA reductase activities of rabbits during adaptation to atherogenic semi-purified diets.

Young adult, male, New Zealand white rabbits were pair-fed low fat, semi-purified diets containing either casein or soy-protein isolate and sucrose or dextrose for 174 days. While casein feeding resulted in hypercholesterolemia, adaptation occurred beginning between 90-120 days of feeding as evidenced by a reduction in mean serum cholesterol concentrations. At the end of the dietary period no atherosclerotic lesions were seen in aortas of rabbits in any of the dietary groups. Serum free and esterified cholesterol concentrations averaged two-fold greater with casein-feeding than those of rabbits fed the soy-protein paired diets. Differences due to carbohydrate type were minimal. Elevations of both free and esterified cholesterol in the low density lipoprotein fraction (1.011 less than d less than 1.031 g/ml, LDL1) and of free cholesterol in the high density fraction (1.079 less than d less than 1.19 g/ml, HDL) were observed. The major cholesterol carrying lipoprotein after adaptation was LDL1 although HDL free cholesterol was increased in the casein groups. Hepatic free cholesterol content was only moderately increased while cholesteryl ester concentrations were elevated three-fold. Hepatic 3-hydroxy-3-methylglutaryl CoA reductase activities were similar among all rabbits at this time. Gall bladder wet weights, including contents, were significantly different in the casein fed animals. Reasons for these differences may include alterations in hepatic acyl-CoA cholesterol acyl transferase (ACAT) activities, lipoprotein production and turnover and/or the rate or extent of gallbladder emptying.

Adaptation, Physiological↗
PubMed1986

Serum chemistry and evidence of renal failure in the North Atlantic fin whale population.

Serum electrolytes, urea nitrogen, creatinine, albumin and globulin were studied in fin whales (Balaenoptera physalus) caught by commercial whalers in the North Atlantic (Denmark Strait area). Blood samples were obtained by catchment or cardiac puncture within 5-15 min of death and analyzed using automated spectrophotometric methods and flame photometry. Osmolality was determined for two serum samples by a vapor pressure method. Linear regressions determined for each measured serum variable vs. chase time suggested that pursuit of the whales prior to capture had no substantive effect on measured serum chemistry. As in other cetaceans, serum sodium, chloride, urea nitrogen and osmolality were distinctly higher in the fin whale than in terrestrial mammals. The total concentration of serum proteins, however, was 1.4-1.8 g/dl lower, on average, than reported in small toothed whales, and was similar to that of domesticated animals. One animal in this population showed alterations in serum chemistry which were consistent with renal failure.

Animals↗
PubMed1985

Serum protein reference values in foals during the first year of life: comparison of chemical and electrophoretic methods.

Normal reference values for serum proteins of foals from birth to 1 year of age have been established. Chemical and electrophoretic/refractometric methods for total protein, albumin, total globulin and Albumin/Globulin (A/G ratio) have also been compared. The biuret total protein method and Bromcresol Green (BCG) method on the Technicon SMA 12/60 autoanalyzer were used and compared with total protein determined via refractometry and albumin determined by Cellulose Acetate (CA) electrophoresis/densitometry. Globulin and A/G ratios were calculated from the chemical method data and compared with that obtained electrophoretically. Total protein, albumin, total globulins and A/G ratios all were in agreement at all sample times studied. Data on the subfractionation of serum globulins via CA electrophoresis is also presented. Wide variations in alpha and beta globulin levels were noted among the foal sera early in life. As a result, two distinct populations of foals with respect to both globulin content and A/G ratio were identified. One of these populations (Group A) appeared to have obtained passive immunity more slowly than the other (Group B) animals. Comparison of these data with clinical cases of foals in which failure of passive transfer was a part suggests that the A/G ratio may be useful in assessing adequate colostral antibody levels in the newborn foal.

Journal Article↗
PubMed1985

Effects of four aromatic organic pollutants on microbial glucose metabolism and thymidine incorporation in marine sediments.

The metabolism of D-[U-14C]glucose and the incorporation of [methyl-3H]thymidine by aerobic and anaerobic marine sediment microbes exposed to 1 to 1,000 ppm anthracene, naphthalene, p,p'-dichlorodiphenyltrichloroethane, and pentachlorophenol were examined. Cell-specific rates of [14C]glucose metabolism averaged 1.7 X 10(-21) and 0.5 X 10(-21) mol/min per cell for aerobic and anaerobic sediment slurries, respectively; [3H]thymidine incorporation rates averaged 43 X 10(-24) and 9 X 10(-24) mol/min per cell for aerobic and anaerobic slurries, respectively. Aerobic sediments exposed to three of the organic pollutants for 2 to 7 days showed recovery of both activities. Anaerobic sediments showed little recovery after 2 days of pre-exposure to the pollutants. We conclude that (i) anaerobic sediments are more sensitive than aerobic sediments to pollutant additions; (ii) [3H]thymidine incorporation is more sensitive to pollutant additions than is [14C]glucose metabolism; and (iii) the toxicity of the pollutants increased in the following order: anthracene, p,p'-dichlorodiphenyltrichloroethane, naphthalene, and pentachlorophenol.

Anthracenes↗
PubMed1985

Degradation and mineralization of the polycyclic aromatic hydrocarbons anthracene and naphthalene in intertidal marine sediments.

The degradation of the polynuclear aromatic hydrocarbons (PAHs) anthracene and naphthalene by the microbiota of intertidal sediments was investigated in laboratory studies. No mineralization of either PAH was observed in the absence of oxygen. Both rates and total amounts of PAH mineralization were strongly controlled by oxygen content and temperature of the incubations. Inorganic nitrogen and glucose amendments had minimal effects on PAH mineralization. The rates and total amounts of PAH mineralized were directly related to compound concentration, pre-exposure time, and concentration. Maximum mineralization was observed at the higher concentrations (5 to 100 mug/g [ppm]) of both PAHs. Optimal acclimation to anthracene and naphthalene (through pre-exposures to the compounds) occurred at the highest acclimation concentration (1,000 ppm). However, acclimation to a single concentration (100 ppm) resulted in initial relative mineralization rates over a range of re-exposure concentrations (1 to 1,000 ppm) being nearly identical. Maximum mineralization of both PAHs occurred after intermediate periods (1 to 2 weeks) of pre-exposure. The fraction of the total heterotrophic population capable of utilizing anthracene or naphthalene as sole carbon source was also greatest after 2 weeks.

Journal Article↗
PubMed1984

The influence of protein and carbohydrate type on serum and liver lipids and lipoprotein cholesterol in rabbits.

The non-lipid portions of semi-synthetic diets appear to be important determinants of hypercholesterolemia and atherosclerosis in the rabbit. Serum and liver lipid concentrations were determined in rabbits which had been pair-fed various protein (casein or soy protein isolate) and carbohydrate (sucrose or dextrose) sources as part of low fat, low cholesterol, semi-synthetic diets. It was verified that casein-containing diets render rabbits hypercholesterolemic, while soy protein caused a degree of hypocholesterolemia. Additionally, sucrose, when fed in conjunction with casein, appears to augment this hypercholesterolemic effect. The distribution of total cholesterol among lipoprotein subclasses was increased in both the intermediate density lipoprotein (IDL) (1.006-1.019 g/ml) and low density lipoprotein (LDL) (1.019-1.063 g/ml) fractions and decreased in the high density lipoprotein (HDL) (1.063-1.21 g/ml) fraction when casein is fed. Soy protein feeding caused relatively more cholesterol to appear only in the IDL fraction when compared with commercial chow fed rabbits. Reasons for these differences may involve the saturation or suppression of endogenous lipoprotein hepatic receptors.

Animals↗
PubMed1984

Congenital lipoprotein lipase deficiency in hyperlipemic kitten siblings.

The nature of the hyperlipemia in two 3-week-old male kittens, one of which was presented with the owner's complaints of retarded growth and white streaks on its eyes, was studied. Hypertriglyceridemia, hyper-cholesterolemia, and reduced Post-Heparin Plasma Lipolytic Activities (PHPLA) were observed in both animals. One of the kittens, however, was more severely affected and in addition, had lipemia retinalis and a marked lactescent, hyperchylomicronemic serum in spite of a short-term fast before sampling. These findings are strikingly similar to those found in human Type I hyperlipoproteinemia due to familial Lipoprotein Lipase (LPL) deficiency. Diagnosis of persistent hyperlipemic syndromes in kittens should include the possibility of LPL deficiency as determined by PHPLA measurements.

Journal Article↗
PubMed1984

Haematology of foals up to one year old.

Packed cell volume, haemoglobin concentration, erythrocyte counts, erythrocyte indices, serum iron, iron binding capacities, total and differential leucocyte counts, platelet counts, total plasma protein, fibrinogen, haptoglobin and icterus index values were determined at 14 different ages in eight Thoroughbred and 14 Quarterhorse foals during the first year of life. Absolute neutrophil numbers in blood decreased and lymphocyte numbers increased during the first months. Absolute eosinophil numbers tended to increase until three months old. Haemoglobin concentration and packed cell volume decreased significantly during the first two weeks and generally stayed in the lower portion of adult horse normal ranges during the remainder of the first year. Mean cell volume decreased to minimum values at approximately four months and then gradually increased. Serum iron was high at birth and decreased rapidly to a minimum at three days old. Total iron-binding capacity increased to a maximum at one month. Serum haptoglobin was generally within the adult normal range at birth. A moderate, but significant, decrease occurred at one week old. Fibrinogen concentration increased to a maximum at five months. Icterus index values decreased rapidly during the first two weeks of life. Minor changes occurred in other parameters measured. Possible causes for the various changes in haematological parameters are discussed.

Animals↗
PubMed1983

Biometry and clinical characteristics of congenital cataracts and microphthalmia in the Miniature Schnauzer.

Forty-two Miniature Schnauzer pups and adults with congenital cataracts and microphthalmia were evaluated by serial ophthalmic examinations, slit lamp biomicroscopic photography, and A-scan ultrasonography. The cataracts were evident when the eyelids opened at 2 weeks, affecting predominantly the lens nucleus and posterior cortex. Lenticonus was evident in 19% of the cataractous lenses. Progression of the cataracts was variable and related to involvement of the equatorial and posterior cortices. Lens-induced uveitis developed in some adult dogs with advanced hypermature cataracts. The globe and lens were smaller than normal in the cataractous eyes, as ascertained by A-scan ultrasonography. Age-matched comparisons of clear lens carrier Miniature Schnauzers and normal Beagles with the cataractous Miniature Schnauzers indicated affected globes and cataractous lenses were reduced 10% to 20% in their anteroposterior lengths. The microphthalmia appeared related to the congenital microphakic cataract.

Animals↗
PubMed1983

Fatty acid composition of serum lipids in fasting ponies.

Alterations in the fatty acid distribution of total lipid extracts and 4 of the major lipid subclasses of serum in ponies fasted overnight and for 4 and 7 days were determined. Although increases in 16:0, 16:1, and 18:3 omega 3 were observed, decreased amounts of 18:0 and 18:2 omega 6 combined to cause no significant change in the saturated to unsaturated fatty acid ratio in the total extracts. Phospholipid became somewhat preferentially enriched in saturated fatty acids due to a decrease in 18:1, although this response was variable. The free fatty acid and triglyceride fractions both showed increases in relative amounts of 18:3 omega 3 and a decrease in 18:0 and a concomitant change in the saturated to unsaturated fatty acid ratio. This endogenous alteration was most likely due to the mobilization of an increased proportion of polyunsaturated fatty acids from tissue sites with their subsequent incorporation into triglyceride by the liver. It probably reflects the type of forage diet on which the animals had been maintained prior to the study. The fatty acid composition of the cholesteryl ester fractions was unchanged during fasting but contained appreciable amounts of the 18:2 omega 6 fatty acid.

Animals↗