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Biomedical subjects

J K Thompson

Publications and source records attributed to J K Thompson.

At least 109 records · Page 6Linked to original sources
PubMed1981

Generalization of frontalis electromyographic feedback to adjacent muscle groups: a critical review.

The widespread utilization of frontalis electromyographic feedback as a general relaxation strategy far preceded empirical evidence demonstrating its efficacy for this purpose. This article reviews parametric studies testing the association between frontalis reduction and concomitant EMG decreases in nontargeted muscle groups. The current research supports the contention that biofeedback reinforces discriminative responding to a specific muscle group and not generalized relaxation to adjacent muscle groups. Methodological problems are noted, and implications for future research are addressed.

Adolescent↗
PubMed1981

Novel patterns of ultraviolet mutagenesis and Weigle reactivation in Staphylococcus aureus and phage phi 11.

The effects of u.v. irradiation on the survival of Staphylococcus aureus and its phage phi 11 were studied. The recA and uvr mutations affected their survival in a similar way to synonymous mutations in Escherichia coli. Weigle reactivation (W-reactivation) of phi 11 occurred in wild-type S. aureus and in a uvr mutant but to a lesser extent than has been found for phage lambda in E. coli. Reactivation was recA-dependent and was accompanied by u.v.-induced mutagenesis in a temperature-sensitive mutant of phi 11. Bacterial mutation to streptomycin resistance was induced by u.v. and was also recA-dependent. In S. aureus, as in E. coli, u.v. was a more effective mutagen in the uvr genetic background. However, a dose-squared response for u.v.-induced mutation of wild-type and uvr strains of S. aureus to streptomycin resistance, and of a trp auxotroph to tryptophan independence, was found only with u.v. doses below 1 J m-2. We suggest that, in relation to the Uvr mechanism of DNA repair, u.v. mutagenesis in S. aureus involves both repairable and non-repairable lesions. As in E. coli, the uvr genetic background reduced the u.v. dose required for maximal W-reactivation of u.v.-irradiated phage. However, there was no enhancement of W-reactivation by post-irradiation broth incubation of S. aureus. Our results are compatible with a non-inducible mechanism for this phenomenon.

DNA Repair↗
PubMed1981

Mineral status of beef cows and sheep on spring pasture fertilized with kieserite.

The utilization of minerals in orchardgrass (Dactylis glomerata L.) fertilized with kieserite (2,240 kg/ha) was examined in spring with lactating beef cows and wether lambs. Kieserite increased the concentration of Mg in vegetative herbage from .22 to .29% ( P less than .01) and of S from .20 to .29% (P less than .01), with little effect on other minerals. Fertilization also increased (P less than .01) apparent absorptions of Mg and S by lambs fed cut orchardgrass, from 24.5 to 36.5% and from 58.6 to 66.9%, respectively, and increased (P less than .01) apparent Mg retention from +.16 to +.33 g/day. Fertilization did not affect dry matter digestibility or apparent absorption of N, Ca or P by lambs. composition of blood and saliva of beef cows grazing fertilized and unfertilized pastures was determined during a 2-week period in early spring. Cows grazing kieserite-treated pastures showed a small increase (P greater than .05) in serum Mg, ultrafiltrable Mg and red blood cell (RBC) Mg, and fewer cows on the fertilized pastures showed severe hypomagnesemia (less than 1.0 mg/100 ml) after the first day of grazing. The decline in blood Mg concentrations was not accompanied by hypocalcemia or by changes in serum Na or K concentrations, but serum inorganic P decreased (P less than .01) markedly during the first 10 days of grazing. Ultrafiltrable Ca in blood was affected by fertilizer and period, but it is questionable whether either ultrafiltrable Mg or Ca would provide a more sensitive index of mineral status than serum concentrations. Concentrations of K, NA and P in saliva were more susceptible to fertilizer and period effects than were concentrations in blood, although all values fell within a normal range. There was no evidence of an inverse relationship between serum Mg and concentration of K in saliva of cows after a change from a winter-type diet to spring herbage containing high levels of N and K.

Animal Feed↗
PubMed1980

The use of a new phage set for typing poultry strains of Staphylococcus aureus obtained from seven countries.

1. Eighty per cent of poultry strains of Staphylococcus aureus tested from French, Belgian, English, West German, Japanese and Argentinian sources were typable using a set of typing phages isolated in this laboratory. Strains from Bulgaria, however, with few exceptions were not typable with this phage set. 2. Strains isolated from lesions generally resembled those from apparently healthy poultry. 3. The existence of two distinct Staph. aureus biotypes on poultry was confirmed by isolates from six of the countries; one of these biotypes closely resembled Staph. aureus variety gallinae as described by Witte et al. (1977).

Animals↗
PubMed1980

Staphylococcus aureus in commercial laying flocks: incidence and characteristics of strains isolated from chicks, pullets and hens in an integrated commercial enterprise.

1. Staphylococcus aureus was able to colonise the surface of chicks as young as 1 d old. 2. The organism was detected in a hatchery particularly in the debris from the hatchers and on the working surfaces at the sexing and vaccination areas. 3. The degree of surface colonisation of chicks and pullets was low during rearing but rose to a maximum at mid-lay (50 weeks) when the organism was readily detectable on almost all hens. 4. Strains of Staphylococcus aureus were characterised by phage-typing and cultural characteristics and found to belong predominantly to poultry phage group B2 of Gibbs et al. (1978a). 5. A detailed description of poultry phage group B2 strains is presented; strains of this type can be considered as a second "live-bird" ecovar when compared with Staph. aureus var. gallinae of Witte et al. (1977).

Animals↗