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Biomedical subjects

D L Ferguson

Publications and source records attributed to D L Ferguson.

At least 19 recordsLinked to original sources
PubMed2001

Loading the problem loader: the effects of target training and shaping on trailer-loading behavior of horses.

The purpose of this study was to develop an effective method for trailer loading horses based on principles of positive reinforcement. Target training and shaping were used to teach trailer-loading behavior to 5 quarter horse mares in a natural setting. All 5 had been trailer loaded before through the use of aversive stimulation. Successive approximations to loading and inappropriate behaviors were the dependent variables. After training a horse to approach a target, the target was moved to various locations inside the trailer. Horses started training on the left side of a two-horse trailer. After a horse was loading on the left side, she was moved to the right side, then to loading half on the right and half on the left. A limited-hold procedure and the presence of a companion horse seemed to facilitate training for 1 horse. Inappropriate behaviors fell to zero immediately after target training, and all the horses successfully completed the shaping sequence. Finally, these effects were observed to generalize to novel conditions (a different trainer and a different trailer).

Animals↗
PubMed1997

Identification of a delta-TIP cDNA clone and determination of related A and D genome subfamilies in Gossypium species.

Tonoplast intrinsic proteins (TIPs) have been implicated in the process of cell elongation, such as occurs in the developing cotton fiber. We have isolated a cDNA clone (997 bp in length) from a cotton (Gossypium hirsutum L.) library which putatively encodes a protein of 248 residues (Mr 25079) with 85% identity to Arabidopsis delta-TIP. The derived amino acid sequence included two conserved sequences associated with major intrinsic proteins (SGxHxNPA at residues 78 to 85, NPA residues at 197 to 199) and a cysteine residue at 116 which is reported to bind mercury in Arabidopsis delta-TIP. The polymerase chain reaction was used to generate partial genomic clones of the cotton delta-TIP. In comparison to other genomic TIP sequences, the number (two) and position of the introns were conserved in cotton. Comparing the TIP sequences from cotton revealed two subfamilies, which were consistently distinguished by a Tsp45I restriction site polymorphism. This polymorphism was used to demonstrate that TIP subfamilies were specific to either the A or D genomes of Gossypium. When delta-TIP DNA fragments were amplified from cDNA of fiber 14 days after anthesis, the A and D were found, indicating the presence of delta-TIP transcripts in these elongating cells.

Amino Acid Sequence↗
PubMed1994

Is communication really the point? Some thoughts on interventions and membership.

This paper presents a brief account of communication interventions and describes recent developments in the field resulting in shifts in intervention focus, perspectives, and strategies. In examining communication interventions as one example of professional efforts to ameliorate the effects of disability, the author concluded that the real point of such efforts is not so much improved communication as membership in society. The concept of membership was explored, including the ways in which individuals construct stories that make the communication acts of individuals with severe disabilities commonplace and socially valuable. Efforts to foster communication (e.g., change behavior, adjust movement) should shift to ensuring that membership in society is achieved.

Adolescent↗
PubMed1993

Inhibition of tobacco NADH-hydroxypyruvate reductase by expression of a heterologous antisense RNA derived from a cucumber cDNA: implications for the mechanism of action of antisense RNAs.

Tobacco plants were genetically transformed to generate antisense RNA from a gene construct comprised of a full-length cucumber NADH-dependent hydroxypyruvate reductase (HPR) cDNA placed in reverse orientation between the cauliflower mosaic virus 35S promoter and a nopaline synthase termination/polyadenylation signal sequence. In vivo accumulation of antisense HPR RNA within eight independent transgenic tobacco plants resulted in reductions of up to 50% in both native HPR activity and protein accumulation relative to untransformed tobacco plants (mean transgenote HPR activity = 67% wild type, mean transgenote HPR protein = 63% wild type). However, in contrast to previous reports describing antisense RNA effects in plants, production of the heterologous HPR antisense RNA did not systematically reduce levels of native tobacco HPR mRNA (mean transgenote HPR mRNA level = 135% wild type). Simple regression comparison of the steady-state levels of tobacco HPR mRNA to those of HPR antisense RNA showed a weak positive correlation (r value of 0.548, n = 9; n is wild type control plus eight independent transformants; significant at 85% confidence level), supporting the conclusion that native mRNA levels were not reduced within antisense plants. Although all transgenic antisense plants examined displayed an apparent reduction in both tobacco HPR protein and enzyme activity, there is no clear correlation between HPR activity and the amount of either sense (r = 0.267, n = 9) or antisense RNA (r = 0.175, n = 9). This compares to a weak positive correlation between HPR mRNA levels and the amount of HPR activity observed in wild-type SR1 tobacco plants (r = 0.603, n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Dehydrogenases↗
PubMed1992

A new method of measuring protein-methionine-s-oxide reductase activity.

A new assay for measuring protein-methionine-S-oxide reductase is reported. The assay measures the conversion of N-(9-fluorenylmethoxycarbonyl)-methionine sulfoxide to N-(9-fluorenylmethoxycarbonyl)-methionine using fluorescence detection after high-performance liquid chromatography separation. Enzyme activity is linear over a 60-min period and the assay is sensitive enough to detect the consumption of only 1% of available substrate. Protein-methionine-S-oxide reductase activity was demonstrated in pea (Pisum sativum L.) chloroplasts, and enzyme levels in leaves of etiolated and light-grown seedlings were compared.

Journal Article↗
PubMed1991

Influence of Water and Temperature Stress on the Temperature Dependence of the Reappearance of Variable Fluorescence following Illumination.

The temperature dependence of the rate and magnitude of the reappearance of photosystem II (PSII) variable fluorescence following illumination has been used to determine plant temperature optima. The present study was designed to determine the effect of a plant's environmental history on the thermal dependency of the reappearance of PSII variable fluorescence. In addition, this study further evaluated the usefulness of this fluorescence technique in identifying plant temperature optima. Laboratory and greenhouse grown potato (Solanum tuberosum L. cv "Norgold M") plants had a thermal kinetic window between 15 and 25 degrees C. The minimum apparent K(m) of NADH hydroxypyruvate reductase for NADH occurred at 20 degrees C. This temperature was also the temperature providing maximal reappearance of variable fluorescence. Soybean (Glycine max [L.] Merrill cv "Wayne") plants had a thermal kinetic window between 15 and 30 degrees C with a minimum apparent K(m) at 25 degrees C. Maximal reappearance of variable fluorescence was seen between 20 and 30 degrees C. To determine if increasing environmental temperatures increased the temperature optimum provided from the fluorescence response curves, potato and soybean leaves from irrigated and dryland field grown plants were evaluated. Although the absolute levels of PSII variable fluorescence declined with increasing thermal stress, the temperature optimum of the dryland plants did not increase with increased exposure to elevated temperatures. Because of variability in the daily period of high temperature stress in the field, studies were initiated with tobacco plants grown in controlled environment chambers. The reappearance of PSII variable fluorescence in tobacco (Nicotiana tabacum L. cv "Wisconsin 38") leaves that had experienced continuous leaf temperatures of 35 degrees C for 8 days had the same 20 degrees C optima as leaves from plants grown at room temperature. The results of this study suggest that the temperature optimum for the reappearance of variable fluorescence following illumination is not altered by the plant's previous exposure to variable environmental temperatures. These findings support the usefulness of this procedure for the rapid identification of a plant's temperature optimum.

Journal Article↗
PubMed1991

Internal parasite levels and response to anthelmintic treatment by beef cows and calves.

Albendazole (methyl 5-propylthio-1 H-benzimidazol-2-yl carbamate) was used as an anthelmintic in a 3-yr study involving 578 beef cows and 438 nursing calves. Infection levels for nematodes, coccidia, and tapeworm were relatively low throughout the 3-yr period. Eggs per gram of feces in cows and calves were lower (P less than .01) 2 wk posttreatment but were not different 5 mo later, when calves were weaned. Cow weight gain, rate and time of conception, and adjusted calf weaning weights were not affected significantly by deworming of either cows or calves. Level of nematode infection measured as eggs per gram of feces was higher (P less than .01) in younger cows than in mature cows. Although deworming with Albendazole lowered (P less than .01) nematode infection levels, no responses were observed in cow or calf performance.

Age Factors↗
PubMed1990

Ubiquitin Pool Modulation and Protein Degradation in Wheat Roots during High Temperature Stress.

Ubiquitin, a key component in an ATP-dependent proteolytic pathway, participates in the response of various eucaryotic organisms to high temperature stress. Our objective was to determine if ubiquitin serves a similar capacity for metabolizing altered proteins in higher plants during stress. Degradation of total proteins was measured, and ubiquitin pools (free versus conjugated) were extracted with an improved protocol from wheat (Triticum aestivum L. cv Len) roots treated at 22, 27, 32, 37, and 42 degrees C for 1 hour and assayed by western blots and radioimmunoassays. Heat-shock protein synthesis was detected by in vivo labeling and autoradiography. Mean half-life of total root proteins decreased from 51 hours at 22 degrees C to 23 hours at 40 degrees C. Ubiquitin pools were extracted better and proteolysis was slowed more by the improved protocol than by a conventional procedure for plant proteins. Amounts of high molecular mass conjugates were elevated and levels of low molecular mass conjugates and free ubiquitin were depressed when roots were treated at 37 or 42 degrees C than at lower temperatures; the same high temperatures also induced synthesis of heat-shock proteins. We concluded that high temperatures increase breakdown of root proteins, which are degraded via the ubiquitin proteolytic pathway. A conjugate with an apparent molecular mass of 23 kilodaltons was tentatively identified as an ubiquitinated histone.

Journal Article↗
PubMed1986

HPLC separated fractions of 99mTc(NaBH4)-HEDP as myocardial infarct imaging agents.

Component fractions of 99mTc(NaBH4)-HEDP mixtures, isolated by anion exchange high performance liquid chromatography (HPLC), have been evaluated as myocardial infarct imaging agents in two animal models. Results from both the isoproterenol-induced myocardial infarction model, and the heat-induced myocardial necrosis model, show that the several HPLC isolated components exhibit significantly different abnormal/normal heart uptake ratios. In addition, the HPLC isolated component of shortest chromatographic retention time exhibits a higher abnormal/normal heart uptake ratio than does 99mTc(Sn)-PyP, the current agent of choice for clinical myocardial infarct imaging.

Animals↗
PubMed1982

In vivo distributions of some component fractions of Tc(NaBH4)-HEDP mixtures separated by anion exchange high performance liquid chromatography.

Anion exchange high performance liquid chromatography has been utilized to separate the component Tc-HEDP complexes of "carrier added" as well as "no carrier added" 99mTc(NaBH4)-HEDP reaction mixtures. The chromatographically separated "carrier added" Tc-HEDP components exhibit distinctly different biodistributions which are directly related to the chromatographic characteristics of the individual components. The Tc-HEDP complexes with shortest retention times, and therefore the lowest negative "charge density" have the maximum uptake on the bone, minimum uptake in the kidney, and fastest blood clearance.

Animals↗
PubMed1981

Anthelmintic activity of albendazole against adult Metastrongylus apri in artificially infected swine.

Three groups of five pigs experimentally infected with lungworm larvae (Metastrongylus apri) were treated with albendazole at 5, 7.5 or 10 mg/kg body weight at 35 days postinfection. The albendazole was administered in the feed. Anthelmintic efficacy, as determined by comparison of postmortem lungworm counts for the treated animals and five infected, untreated controls, was 32.6% at 5 mg/kg, 44.3% at 7.5 mg/kg and 60.7% at 10 mg/kg. The 60.7% reduction in lungworms was statistically different at the 5% level of significance. In a second experiment, three groups of five pigs experimentally infected with lungworm larvae (Metastrongylus apri) were treated continuously for 5 days with albendazole in the feed at 10, 20 or 30 ppm, starting at 35 days postinfection. The anthelmintic efficacy, again determined by comparison of postmortem lungworm counts for the treated pigs and five infected, untreated controls, was 99.2% at 10 ppm, 99.9% at 20 ppm and 100% at 30 ppm. These mean reductions from the control values were significant (P greater than .01).

Albendazole↗