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Biomedical subjects

E M Clark

Publications and source records attributed to E M Clark.

At least 37 records · Page 2Linked to original sources
PubMed1982

Association of an endophytic fungus with fescue toxicity in steers fed Kentucky 31 tall fescue seed or hay.

Previous research has implicated an endophytic fungus as being associated with fescue toxicity (summer syndrome) in cattle grazing Kentucky 31 tall fescue (Festuca arundinacea Schreb.) pastures. Hay and seed were harvested from Kentucky 31 pastures known to be either fungus-free or heavily infested with an endophytic fungus identified as Acremonium coenophialum Morgan-Jones and Gams. Four diets containing either 60% fungus-free seed, 60% fungus-infested seed, 85% fungus-free hay or 85% fungus-infested hay were group-fed to three steers each (avg wt 239 kg) in a 53-d feeding trial. Presence of the fungus reduced (P less than .05) daily gains (kg/d) in steers fed either the seed diets (.96 vs .20) or the hay diets (.66 vs .28). Feed intake was depressed 36% for the seed diets and 8% for the hay diets when the fungus was present. Rectal temperatures were elevated .6 C (P less than .05) for both groups receiving diets containing the fungus, but respiration rate was elevated only in the fungus-infested seed group. In vitro dry matter disappearance was not decreased by presence of the fungus. Steers receiving fungus from either seed or hay were nervous and highly excitable, which resulted in large variations in plasma epinephrine and norepinephrine concentrations. The results of this experiment further implicate an endophytic fungus as being associated with fescue toxicity.

Animals↗
PubMed1980

Data integrity in a general practice computer system (CLINICS).

The accuracy of computer held medical information may be of critical importance in patient care, therefore it is important not only to know the error rate in the stored data but also to know the effectiveness of error checking and detection programmes. This paper reports on the errors which were detected in the University of Southampton Primary Medical Care computer system (CLINICS) by checking the consistency between stored data and incoming data. Seven per cent of incoming data had important errors of kinds not normally detected by many medical record systems. The majority were traced either to the registration of new patients or to the doctors failing to pay adequate attention to detail in their record keeping (or to their legibility). They have been subsequently corrected, and it is calculated that the stored data contains less than 1% errors. We suggest ways of improving this; and conclude that certain items are essential to general practice information systems.

Computers↗
PubMed1980

Satellite DNA in large marker chromosomes of methotrexate-resistant mouse cells.

The additional segments of five large marker chromosomes of methotrexate-resistant mouse melanoma PG19T3 cells are shown to consist of C-banding material. In situ hybridization indicates that these additional segments also contain a high proportion of sequences that will cross hybridize with mouse satellite DNA. Analytical density gradient centrifugation suggests that up to 60% of the DNA in the additional segments may be in the form of satellite DNA. Incorporation of bromodeoxyuridine for one complete S phase and staining with the Hoechst 33258 fluorescence plus Giemsa technique reveals complex asymmetries within the additional segments. These asymmetries are interpreted as showing a large repeating unit, which is likely to be involved in the amplification of the dihydrofolate reductase gene.

Animals↗
PubMed1980

A new design concept for an audio dosimeter.

A design concept for a new audio dosimeter is presented which can be used to evaluate employee exposure to both continuous and impulsive noise more accurately. Unlike existing dosimeters, the instrument is capable of eliminating the influence of impulsive sounds upon the employee exposure or "dose." The concept relies upon an interpretation of the intent of existing and proposed U.S. Department of Labor regulations with regard to the evaluation of continuous and impulsive sounds. This paper presents the rationale for the design concept, the block diagram of the microprocessor-based instrument, and a summary of its intended operation.

Equipment and Supplies↗
PubMed1979

The development of resistance to methotrexate in a mouse melanoma cell line. I. Characterisation of the dihydrofolate reductases and chromosomes in sensitive and resistant cells.

PG19T3 mouse melanoma cells were selected for resistance to methotrexate. Nine sub-lines that are resistant to concentrations of methotrexate ranging from 1.27 x 10(-7) M, to 1 x 10(-4) M methotrexate were selected and characterised in terms of their content of dihydrofolate reductase activity and their chromosomes. The intracellular level of dihydrofolate reductase activity increases with increasing resistance such that at the highest level of resistance PG19T3:MTXR10(-4)M cells contain approximately 1,000 fold more enzyme activity than the parental PG19T3 cells. It is shown that the enhanced activity is due to an increase in the amount of the enzyme rather than any structural change to the enzyme in resistant cells. Comparisons of pH activity profiles, profiles under different activating conditions and titrations with methotrexate suggest that the sensitive and resistant cells contain identical dihydrofolate reductases. Analysis of the chromosomes of resistant cells shows the presence of up to 5 large marker chromosomes which contain homogeneously staining regions after G-banding. These same regions stain intensely after C-banding and fluoresce brightly after staining with Hoechst 33258. The size of homogeneously staining regions increases throughout the process of selection. For one marker chromosome this increase may have been mediated via a ring chromosome.

Animals↗
PubMed1979

Respiratory morbidity and exercise-induced bronchoconstriction in children.

A sample of 99 children had lung function tests before and after exercise. Sixteen had a decrease in lung function after exercise (forced expiratory flow) of more than 20 per cent, which indicated an important degree of exerciseinduced bronchospasm. Review of the medical records for the total sample revealed that those with exercise-induced bronchospasm had a higher consultation rate for respiratory symptoms, while their consultation rate for non-respiratory symptoms was the same as the remainder of the sample. These findings suggest that bronchial lability may be a predisposing factor in some respiratory diseases.

Bronchial Spasm↗
PubMed1976

Cholinomimetic teratogens. IV. Effects of the genotype for muscular dystrophy in chickens.

Embryos of a family of chickens homozygous for muscular dystrophy (md/md) reacted with a higher incidence of malformations to treatment with carbachol than did White Leghorn embryos. The same difference in response of embryos from the two stocks occurred after treatment with sulfanilamide. Embryos of reciprocal crosses between these two stocks differed greatly, however, in their response to carbachol, F1 embryos from dystrophic hens producing a much higher incidence of malformations than did those from Leghorn hens. In contrast, both F1 sibs reacted similarly to sulfanilamide, the teratogenic effects being intermediate between those of embryos from the parent stocks.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Weight locus of control and weight-related attitudes and behaviors in an overweight population.

Rotter's [Psychol. Monogr. 80 (1966)] construct of internal-external control of reinforcement led to the conceptualization of locus of control as a personality construct that can be used to predict behavior. More specific measures of locus of control in particular behavioral domains have followed. In the present study, the Weight Locus of Control Scale (WLOC) was used to predict weight-related attitudes and behaviors of overweight individuals, as well as their responses to health education materials (HEM) on weight loss. The WLOC scores predicted responses to baseline weight-related measures such as etiology of obesity, confidence in weight loss behaviors, and behavioral intention. In addition, WLOC scores predicted participants' reactions to the HEM, as well as the actual number of weight loss ideas from the HEM that the participants tried by the 1-month follow-up assessment. The results are discussed in terms of the validity of the WLOC and implications for future development of effective HEM.

Adult↗