PubMed Health⌕ Search

Biomedical subjects

H H Casper

Publications and source records attributed to H H Casper.

15 recordsLinked to original sources
PubMed1995

Use of epidemiologic principles to identify risk factors associated with the development of diarrhea in calves in five beef herds.

The objective of the study reported here was to identify and measure risk factors associated with the incidence of diarrhea in calves in 5 beef herds in North Dakota. Risk factors associated with calves developing diarrhea during the 1992 calving season were used to develop the following intervention strategies that were implemented during 1993: heifers calved in a separate location, diarrheal calves and their dams were placed in a quarantine area, and pregnant cattle were fed a diet supplemented with protein and copper. The risk of calves developing diarrhea was 5 times higher during the first year, compared with the second year, suggesting that the management changes made during the second year were contributing factors in reducing the percentage of calves with diarrhea. The risk of diarrhea developing in calves born to heifers was 3.9 times greater than that in calves born to cows. Analysis of our data indicated that the use of an epidemiologic approach can identify risk factors, which can lead to the development of intervention procedures that may decrease the incidence of diarrhea in calves in beef herds.

Animals↗
PubMed1993

Two new modified trichothecenes from Fusarium sporotrichioides.

Two new modified trichothecenes, 2-deoxy-11-epi-3 alpha-hydroxysambucoin [1] and 2-deoxy-11-epi-12-acetyl-3 alpha-hydroxysambucoin [2], were isolated from Fusarium sporotrichioides culture. This is the first report of modified trichothecenes where the two six-membered rings are cis-fused. Structures were elucidated using gc-ms, nmr, X-ray crystallography, and other spectroscopic techniques. Compounds 1 and 2 were screened for relative cytotoxicity in cultured baby hamster kidney (BHK-21) cells and found to be non-toxic.

Animals↗
PubMed1991

Properties of a 4-ene-3-ketosteroid-5 alpha-reductase in cell extracts of the intestinal anaerobe, Eubacterium sp. strain 144.

When Eubacterium sp. 144 was grown in the presence of progesterone, extracts of these cells contained a 4-ene-3-ketosteroid-5 alpha-reductase (5 alpha-reductase). No evidence for the presence of a 5 beta-steroid-reductase or a 5 alpha to 5 beta-steroid-isomerase was found. 5 alpha-Reductase activity was dependent on reduced methyl viologen as the electron donor and this could be generated biologically by adding pyruvate or H2 to cell extracts or chemically by adding sodium dithionite. NADH or NADPH with or without flavin nucleotides were not electron donors for 5 alpha-reductase. Most of the 5 alpha-reductase activity (60-65%) of crude extracts was located in the membrane fraction and the enzyme was solubilized by treatment with 1% Triton X-100. Optimum 5 alpha-reductase activity occurred at pH 7.0-7.5 in potassium phosphate buffer but was stimulated by Tris-HCl buffer (pH 8.0-9.0). 5 alpha-Reductase activity was highest at 10% (v/v) methanol and was progressively inhibited by higher methanol concentrations. Sulfhydryl reagents strongly inhibited 5 alpha-reductase but the enzyme was not affected by other metabolic inhibitors. Extracts prepared from cells induced with 16-dehydroprogesterone and grown without hemin contained 5 alpha-reductase and 16-dehydroprogesterone-reductase activities equivalent to those found in extracts of induced cells grown with hemin. This indicates that hemin is not required for the synthesis of active steroid double bond-reductases in strain 144.

Cholestenone 5 alpha-Reductase↗
PubMed1991

Novel occurrence of cyclopiazonic acid in sunflower seeds.

Cyclopiazonic acid (CPA), a secondary metabolite produced by several species of Aspergillus and Penicillium, was detected in moldy sunflower seed screenings fed to sows who experienced conception problems and feed refusal. Tandem mass spectrometry confirmed the CPA which was estimated by thin-layer chromatography (TLC) to be present at 10 ppm. A Penicillium species was isolated from the moldy seeds, but in culture it did not produce CPA.

Animals↗
PubMed1989

Evaluation of vitamin K3 feed additive for prevention of sweet clover disease.

Sweet clover poisoning in cattle is caused by an anticoagulant (dicumarol) that is formed in moldy sweet clover hay. Previous experiments with vitamin K3 and vitamin K1 in therapy trials indicated that vitamin K1 was effective in reducing prothrombin times but vitamin K3 was not. As a possible alternative in the use of toxic sweet clover hays, vitamin K3 was evaluated to see if it would prevent hemorrhagic crises when fed to cattle consuming toxic sweet clover hay. Vitamin K3 levels of 0, 0.45, 4.5, 11, and 45 mg/kg body weight/day were fed to 173-235-kg steers consuming toxic (40-50 ppm dicumarol) sweet clover. The 45-mg K3/kg/day supplement was not palatable and had to be discontinued. The 0.45, 4.5, and 11-mg K3/kg/day supplements did not significantly reduce the prothrombin times as compared to the 0-mg K3/kg/day group.

Animals↗
PubMed1985

Vitamin K treatment of sweet clover poisoning in calves.

Dicumarol poisoning was reproduced by feeding naturally spoiled, sweet clover hay, which contained a minimum of 90 ppm dicumarol. Vitamin K1 administered IM was effective in treating the disease at dosages of 1.1, 2.2, and 3.3 mg/kg of body weight. Vitamin K3 treatment by various routes and dosages was ineffective.

Animals↗
PubMed1981

Occurrence and range of dicumarol concentrations in sweet clover.

The dicumarol concentration in 272 cured sweet clover samples from 4 counties in North Dakota was determined. Dicumarol concentrations ranged from 0 to 164.7 mg/kg of sweet clover, with 64.6% of the 272 samples containing less than 10 mg/kg. Round bales were significantly (P less than 0.05) higher in dicumarol concentration (mean of 22.9 +/- 3.10 mg/kg) than were stacks or silage (means of 1.8 +/- -6.3 mg/kg and 0.6 +/- 2.1 mg/kg, respectively). The outer section of core samples taken from round bales contained significantly (P less than 0.0021) higher concentrations of dicumarol than did the inner section of the core, with means of 30.8 mg/kg and 16.6 mg/kg, respectively. A significant (P less than 0.0001) correlation existed between crude protein and dicumarol values (r = 0.44).

Animal Feed↗
PubMed1981

Survey of North Dakota sunflower seeds for aflatoxin.

In a survey of oil-type sunflower seeds, 89 samples were collected from 32 storage bins in 10 counties of North Dakota in 1979. None of these survey samples exceeded the 20 ppb Food and Drug Administration aflatoxin guideline. Four research samples, from 2 grossly spoiled storages, contained 100-1100 ppb aflatoxin B1. This research is believed to be the first to document natural aflatoxin contamination in sunflower seeds.

Aflatoxins↗
PubMed1978

This layer chromatographic determination of aflatoxin B1 in corn silage.

A procedure is described for the purification and quantitation of aflatoxin B1 in corn silage. The toxin is extracted and partially purified using parts of the AOAC minicolumn detection method. The extract is further cleaned up on a 2-step minicolumn and is then analyzed by using thin layer chromatography. Essentially all interferences are removed when the procedure is applied to moldy and non-moldy corn silage. The estimated limit of detection is 5 microgram aflatoxin B1/kg corn silage, and 73 +/- 8% of the added aflatoxin B1 (20 and 85 microgram/kg) was recovered. No aflatoxin B1 was detected in 270 samples collected from 19 silage piles in late fall 1976 and early spring 1977. This procedure also removes interferences associated with moldy corn and mixed feeds.

Aflatoxins↗
PubMedDate not supplied

Two new trichothecenes from Fusarium sporotrichioides.

Two new trichothecenes, 8-n-pentanoylneosolaniol and 8-n-hexanoylneosolaniol, were isolated from corn grits cultured with Fusarium sporotrichioides. The structures of these compounds were elucidated using gc-ms, nmr, X-ray crystallography, and other spectroscopic techniques. Seven known trichothecenes were also isolated, and the relative cytotoxicity of these nine trichothecenes in cultured baby hamster kidney (BHK-21) cells was determined.

Animals↗
PubMedDate not supplied

Tissue fluoroacetate residues in prairie dogs dosed with low-level sodium monofluoroacetate.

A total of 83 black-tailed prairie dogs (Cynomys ludovicianus) from South Dakota were subjected to low-level treatment with sodium monofluoroacetate (Compound 1080) in the laboratory (0.01-0.30 mg 1080/kg). The acute oral median lethal dose (LD50) of 1080 administered by oral gavage was established at 0.173 mg/kg. To assay fluoroacetate residues, 8 kinds of tissue from each of 10 prairie dogs dead of low-level 1080 poisoning were analyzed by capillary gas chromatography-mass spectrometry. Of the total of 79 tissues analyzed, 73 contained less than 100 ppb fluoroacetate, and 67 contained less than 50 ppb fluoroacetate. To test the effect of secondary poisoning on non-target species, 8 European ferrets (Mustela furo) were fed ground whole carcasses of prairie dogs dead of low-level 1080 poisoning, with no observable ill effects on the ferrets.

Animals↗
PubMedDate not supplied

Fluoroacetate residues in ground squirrel and coyote tissues due to primary or secondary 1080 poisoning.

Fluoroacetate residues in various tissues of 1080-poisoned ground squirrels and coyotes are listed. The tissues (excluding the stomach) of squirrels poisoned with an average of 0.8 mg 1080/kg (low dose) contained from 182 to 1309 ppb fluoroacetate. In squirrels poisoned with an average of 4.8 mg 1080/kg (high dose), the tissue residues ranged from 535 to 9754 ppb fluoroacetate. Tissues from coyotes which died after consuming 1080-poisoned ground squirrels were also analyzed for fluoroacetate residues. Residues in these coyote kidneys and livers ranged from less than 10 ppb to 95 ppb fluoroacetate. The residue findings in this research indicate that a diagnostic assay for 1080 in tissues must be reliable at 10 ppb (or less) fluoroacetate.

Animals↗
PubMedDate not supplied

Capillary gas chromatographic-mass spectrometric determination of fluoroacetate residues in animal tissues.

A method for the quantitative determination of fluoroacetate (FAC) residues in animal tissues is described. The procedure involves tungstic acid extraction, partitioning into ethyl acetate, evaporation of ethyl acetate, derivatization with pentafluorobenzyl bromide (PFB), and analysis of the resulting derivative (PFB-FAC) by capillary gas chromatography-mass spectrometry (CGC-MS) with specific ion monitoring (SIM). The tungstic acid system extracted 96.8 +/- 4.2% of the endogenous 14C-1080 residues in rat tissues. Recovery of FAC during the extraction, purification, and derivatization procedures is established by use of a 14C-FAC spike. 1,2-Dibromobenzene is used as an internal standard for the CGC-MS analysis. PFB-FAC is identified on the basis of comparative retention times and the relative intensities of m/z 257.9 and 181.0. PFB-FAC is quantitated by comparing the response at m/z 257.9 to a PFB-FAC standard curve. Routine sensitivity of the method allows determination of 10 ppb fluoroacetate in tissue.

Animals↗
PubMedDate not supplied

Forage nitrate analysis: laboratory performance study.

Four forage samples were analyzed by 16 laboratories for KNO3 content. Individual reported KNO3 values varied widely for each sample; coefficients of variation for the 4 samples were 36.0, 51.0, 12.8, and 55.0%. Recovery of KNO3 from the spiked sample averaged 105%. The analytical results, as a group, were unacceptable both statistically and for use in feeding recommendations. Three values reported could have resulted in feeding potentially toxic forage to livestock.

Nitrates↗