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Biomedical subjects

L G Hansen

Publications and source records attributed to L G Hansen.

At least 109 records · Page 6Linked to original sources
PubMed1979

Comparison of the errors due to the use of gauze and the use of filter paper in the gravimetric chloride titration sweat test.

Potential sources of error in the Gibson and Cooke method of sweat testing using gauze and filter paper as collection media as described. The absolute chloride content of gauze was higher than that of filter paper; however, the variability of chloride contents between the two was insignificant. Complete chloride elution from filter paper requires more time than elution from gauze. A method of determining probability of a clinically acceptable measurement based on sweat sample size, chloride determination, and variability of chloride in collection media is also described.

Chlorides↗
PubMed1979

Cadmium from soil amended with sewage sludge: effects and residues in swine.

Liquid digested sewage sludge from a Chicago waste treatment plant was applied to experimental corn plots starting in 1968. The treatment plant received a high proportion of industrial effluent and the sludge averaged about 200 ppm Cd (dry weight). Corn grain harvested from the plots in 1974 was fed to growing swine for 56 days, and other swine were permitted to forage on the plots during the winters of 1975-76 and 1976-77. The sludge-fertilized corn contained higher concentrations of nutrient and toxic elements, but did not interfere with swine performance. Minor changes in hepatic microsomal oxidases and red blood cells accompanied significant increases in renal Cd and decreases in hepatic Fe. Swine foraging on these plots ingested considerable amounts of sludge soil and accumulated significantly higher concentrations of renal Cd. At lower rates of sludge application the swine outperformed those foraging both on control plots and those receiving heavy sludge applications in terms of weight gain, in-utero piglet survival, blood hemoglobin, and tissue Fe concentrations.

Animal Feed↗
PubMed1979

Residues and effects from feeding high concentrations of hexachlorobenzene to broiler cockerels.

Eight-day old broiler cockerels received 0, 1, 10, or 100 ppm dietary hexachlorobenzene (HCB) for 25, 38, or 52 days. Treated birds grew faster for the first 25 days, but the trend was reversed at later times so there was no net weight difference at 52 days. Birds receiving 100 ppm dietary HCB had significantly enlarged adrenal glands at 38 days and enlarged livers at 38 and 52 days. Equilibrium concentrations in adipose tissue 12 to 13 times the dietary concentration were reached by 23 days in birds receiving 10 or 100 ppm HCB. Birds receiving 1 ppm concentrated HCB more effectively in the fat and did not reach equilibrium until 23 to 38 days.

Animals↗
PubMed1978

An improved assay method for serum vitamins A and E using fluorometry.

A micromethod for assay of serum vitamins A and E with the use of fluorometry is described. The procedure is a modification of previously described methods eliminating two potentially hazardous reagents, hexane and lithium aluminum hydride, as major components. Comparison with previous methods using n-hexane shows good agreement, as well as satisfactory precision.

Fluorometry↗
PubMed1978

Measurement of chloride in sweat by use of a selective electrode and strip-chart recorder.

We describe a method for direct potentiometric measurement of sweat chloride by use of a chloride-selective electrode, with strip-chart recording of the measurement to facilitate interpretation of the measurement. Comparison of this method and the Gibson and Cooke method [Pediatrics 23, 545 (1959)] gave a correlation coefficient of 0.86. Recording of the same test at various pressures showed that different pressures had little effect if they were kept constant.

Chlorides↗
PubMed1977

Distribution, dilution and elimination of polychlorinated biphenyl analogs in growing swine.

Growing swine were given 15 mg/kg po of purified polychlorinated biphenyl analogs and a commercial mixture. Backfat biopsies for 16-18 weeks exhibited two-compartment elimination kinetics when based on concentration. Total body fat was estimated from potassium-40 abundance, and the calculated total fat load indicated that most of the decline in residue concentrations was due to dilution by growth and expansion of the fat compartment. Redistribution in the fat was apparent for various analogs at different times, and tissue distribution varied significantly among analogs.

Adipose Tissue↗
PubMed1977

Tissue distribution of PCB components in swine and sheep fed three different rations containing Aroclors 1242 and 1254.

Growing swine and sheep were fed three dietary variations containing 20 ppm of Aroclors 1242 or 1254 for 13 to 15 weeks. Generally, Aroclor 1254 residues were higher; higher 1242 residues in swine blood, spleen, and ovary are attributed to persistent major components of this Aroclors. Some minor differences in total PCB were observed with varying diets, but peak composition did not vary. Some lower chlorinated components maintained higher levels in the blood relative to other components; other components were selectively accumulated in tissues such as fat and muscle. Blood and fat residues in sheep declined during the last weeks of feeding. Microsomal oxidase levels were elevated in response to PCB and diet in both species, but the response was greater in sheep. Sheep liver microsomes were capable of metabolizing pure analogs and components of Aroclor 1242. Major differences in Aroclor profiles can be demonstrated between swine and sheep residues and total residues can be estimated by measuring selected peaks in blood and backfat. The peaks which provide the most reliable estimate of total PCB residue vary with species and Aroclor.

Animal Feed↗
PubMed1977

Effects and residues of dietary hexachlorobenzene in growing swine.

Crossbred weanling gilts were fed a standard ration containing 0, 1, 10, or 100 ppm purified hexachlorobenzene (HCB) for 13 wk. No mortalities, ill health, neurological disorders, or significant depressions in weight gain were observed. Postmortem examination revealed brightly fluorescent livers at all levels of HCB. The group receiving 100 ppm had a tendency for smaller spleens, larger livers with swollen hepatocytes, and decreased lymphocytes. HCB accumulated in the dissectable fat of growing swine to concentrations five- to sevenfold higher than the dietary concentration; residues in 11 other tissues examined were below the dietary concentration.

Adipose Tissue↗
PubMed1976

Apparent pharmacokinetics of PCB components in growing pigs and lambs when fed a ration containing Aroclor 1254.

Young growing lambs and pigs were fed a ration containing 200 ppm of Aroclor 1254 for 35 days and then switched to "clean" feed. Blood and fat samples were collected periodically throughout the experiment and analyzed for components of Aroclor 1254 and total PCB. Several components are apparently accumulated and eliminated at different rates within each species, as seen by comparing gas chromatograph tracings, accumulation ratios and apparent rate constants of elimination. Differences in accumulation and elimination of Aroclor components, some of which were apparently caused by differences in growth rates, were also seen between pigs and lambs. Variable growth rates of different species of food producing animals are an important factor to consider when dealing with tissue distribution and residues of polychlorinated biphenyls for determination of carcass disposition, as well as accumulation of toxic concentrations in the animal body.

Adipose Tissue↗
PubMed1976

Absorption of vitamin A in patients with cystic fibrosis. Absorption is best with emulsified vitamin A alcohol.

Vitamin A absorption tests using vitamin A palmitate and alcohol separately in oil and oil-water emulsions were done on 43 patients with cystic fibrosis. Patients were given 7,000 units of vitamin A per kilogram of body weight with a fatty breakfast. Pancreatic enzymes were not given with the test meal and were withheld for five hours from start of test. Blood was drawn before administration of the vitamin and at three and five hours after administration. Serum vitamin A levels were estimated using the Carr-Price technique. The percentages of patients with normal vitamin A absorption were 85 with vitamin A alcohol in oil-water emulsion, 61 with vitamin A alcohol dissolved in oil, 64 with vitamin A palmitate in oil-water emulsion, and 19 with vitamin A palmitate in oil. The number of stools per day is an inverse indicator of retention time in the intestine. Absorption of fat soluble vitamins is always abnormal when a patient has four or more stools a day. The observations that cystic fibrosis patients with abnormal liver biopsies have poor absorption of vitamin A were not statistically significant. The question of the effect of cirrhosis in cystic fibrosis on vitamin A absorption remains unresolved.

Adolescent↗
PubMed1976

Model ecosystem evaluation of the environmental impacts of the veterinary drugs phenothiazine, sulfamethazine, clopidol, and diethylstilbestrol.

Four veterinary drugs of dissimilar chemical structures were evaluated for environmental stability and penchant for bioaccumulation. The techniques used were (1) a model aquatic ecosystem (3 days) and (2) a model feedlot ecosystem (33 days) in which the drugs were introduced via the excreta of chicks or mice. The model feedlot ecosystem was supported by metabolism cage studies to determine the amount and the form of the drug excreted by the chicks or mice. Considerable quantities of all the drugs were excreted intact or as environmentally short-lived conjugates. Diethylstilbestrol (DES) and Clopidol were the most persistent molecules, but only DES bioaccumulated to any appreciable degree. Phenothiazine was very biodegradable; sulfamethazine was relatively biodegradable and only accumulated in the organisms to very low levels. Data from the aquatic model ecosystem demonstrated a good correlation between the partition coefficients of the drugs and their accumulation in the fish.

Animals↗
PubMed1976

Effects of feeding polychlorinated biphenyls to broiler cockerels in three dietary regimes.

Polychlorinated biphenyls (Aroclor 1242 and 1254) were fed at 20 p.p.m. to hybrid broiler cockerels between one and nine weeks of age in three dietary variations. The Aroclors did not affect growth or feed efficiency and no consistent histopathological lesions could be attributed to them. There was a low incidence of hydropericardium in birds receiving Aroclor 1254. Fatty liver was observed in some birds receiving Aroclor 1242 and a single bird receiving this PCB exhibited liver necrosis. Moderate increases in liver weight and mild decreases in the relative weight of the spleen were attributable to PCB.

Adipose Tissue↗
PubMed1976

Effects on growing swine and sheep of two polychlorinated biphenyls.

Dietary polychlorinated biphenyls in feeds at concentrations of 20 ppm given to swine and sheep between weaning and time of their reaching market weight reduced feed efficiency and rate of gain. These effects were of the same magnitude as those observed in swine and sheep fed sub-optimal diets, and in swine, there was a highly significant interaction between diet and polychlorinated biphenyl effects. Gross and microscopic lesions were few, consisting of increased frequency of pneumonia in swine and sheep and of increased frequency and severity of gastric lesions in swine. The gastric lesions in swine consisted of erosions of surface mucosa; these lesions were greater in the swine given the higher dose levels when they included hypertrophy, hyperplasia, and deep ulcerative lesions.

Animals↗