PubMed HealthSearch

Biomedical subjects

D Porter

Publications and source records attributed to D Porter.

At least 37 records · Page 2Linked to original sources

Evaluation of reproductive function of female rats exposed to radiofrequency fields (27.12 MHz) near a shortwave diathermy device.

In recent years, there has been increased concern regarding effects of operator exposure to the electromagnetic (EM) field associated with shortwave diathermy devices. The present study was designed to investigate the effects, on rats, of repeated exposure to such an EM field. Following repeated exposure for 5 wk, a reduction in fertility occurred as indicated by a reduced number of matings in exposed rats compared to sham-irradiated rats and a reduction in the number of rats that conceived after mating. The data suggest that female operators could experience reduced fertility, if they remained close to the console for prolonged periods. This has particular significant for the physiotherapy profession.

Animals

The effect of footwear mass on the gait patterns of unilateral below-knee amputees.

This study reports an investigation into the effect of shoe mass on the gait patterns of below-knee (BK) amputees. Ten established unilateral BK, patellar-tendon-bearing prosthesis wearers were assessed using a VICON system of gait analysis. Incremental masses of 50g (up to 200g) were added to the subjects' shoes and data captured as they walked along a 15m measurement field. Coefficients of symmetry of various parameters of the swing phase (knee frequency symmetry, swing time symmetry) were measured and their correlation was tested with the patient's preferred shoe mass and also their own shoe mass, all expressed as a proportion of body mass. The subjects' 'preferred' shoe mass (139-318g) showed the greatest symmetry in all the parameters examined (correlations 0.78-0.81 p less than 0.01 and less than 0.005), whereas there was no correlation between the subjects' own shoe mass (121-325g) and the symmetry coefficients measured.

Amputation, Surgical

Progressive systemic sclerosis: Part 2--Nursing management.

Multiple body systems can be affected by scleroderma. Satisfactory coping and life-style alterations will depend on numerous factors, including the nature and extent of organ involvement, individual coping style, and health professional services provided. Because of the low incidence of this disease, nurses may have little knowledge about the nursing management. Because of the nature of the disease's complications, the nephrology or dialysis nurse may care for more scleroderma patients than other hospital nurses.

Adaptation, Psychological

Federal nutrition policies: impact on dietetic practice.

Current federal nutrition policies are likely to have a major impact on dietetic practice. Several examples have been selected to explain why and how members of the American Dietetic Association and other nutrition professionals should become involved in policy development and implementation.

Cholesterol

Self-service computerized bibliographic retrieval: a comparison of Colleague and PaperChase, programs that search the MEDLINE data base.

Colleague and PaperChase are the two most widely used computer systems designed specifically for clinicians and scientists who wish to search the National Library of Medicine's MEDLINE data base of references to the biomedical literature. The present study compares the performance of these two systems. Two matched groups of second-year medical students each received 3 hr of instruction, one group in Colleague, the other in PaperChase. Each student then attempted 10 test searches. The next day the groups were reversed, and each student attempted 5 additional searches. During 3 1/2 hr allocated for searching, users of Colleague attempted 64 test searches and retrieved 326 target references; users of PaperChase attempted 78 searches and retrieved 496. Users of Colleague took a mean of 2.2 min and spent a mean of $1.20 to find each target reference; users of PaperChase took 1.6 min and spent $0.92. We conclude that after limited training, medical students find more references faster and at lower cost with PaperChase than with Colleague.

Computer User Training

Specificity of amphibian and reptilian pituitaries for various forms of gonadotropin-releasing hormones in vitro.

In vitro perifusion was employed to compare the potencies of mammalian, avian, salmon, and lamprey gonadotropin-releasing hormones (GnRHs) on the release of luteinizing hormone (LH) from the pituitaries of an amphibian (Rana pipiens) and a reptile (Chrysemys picta). The chicken-I and salmon GnRH variants were equipotent with mammalian GnRH in both the frog and the turtle glands. By contrast, the lamprey GnRH was inactive (less than 1% as potent as the others). Lamprey GnRH also failed to stimulate LH release or to induce GnRH priming when administered chronically to the frog gland. These results support the hypothesis that the GnRH receptors on nonmammalian pituitary cells are much less specific than those of the mammal with regard to the amino acid at position 8 of the GnRH molecule. These data suggest that the native GnRH variant or the one most like that found in the brain of a species is not necessarily the most potent biologically in that species. However, the nonmammalian pituitary does show some specificity with regard to the structure of natural GnRHs in that none of the tetrapod species studied is responsive to lamprey GnRH.

Animals

Growth of bacteria with dimorphic vegetative cell cycles.

A mathematical model of the growth of bacteria with dimorphic cell cycles is described. In these bacteria motile swarmer cells differentiate to stalked reproductive cells and the proportions of these cell types change in a characteristic fashion during growth. The selection of parameters to fit the model to experimental data can result in the elucidation of the factors controlling the differentiation of swarmer cells.

Bacteria

Energy expenditure during front crawl swimming: predicting success in middle-distance events.

Male (n = 25) and female (n = 14) competitive swimmers were studied during tethered (breaststroke) and free (front crawl) swimming to determine the validity of calculating exercise oxygen uptake (VO2) from expired gas samples taken immediately after the activity. Based on a single 20-s recovery VO2, the swimmers' VO2 max was correlated with performance in a 400-yd (365.8-m) front crawl swim. The best predictors of VO2 max for trained swimmers were lean body weight and stroke index (r = 0.97). The single best predictor of performance in the 365.8-m front crawl swim was the distance per stroke (r = 0.88), whereas the combination of distance per stroke and VO2 max (ml/kg LBW/min) correlated 0.97 with performance in the swim. This study demonstrates that it is possible to accurately determine the VO2 during maximal and submaximal swimming using a single, 20-s expired gas collection taken immediately after a 4-7 min swim. These findings demonstrate the importance of stroke technique on the energy cost and variations in performance during competitive swimming.

Adolescent

E1a regions of the human adenoviruses and of the highly oncogenic simian adenovirus 7 are closely related.

Simian adenovirus 7 (SA7) is a highly oncogenic virus, capable of causing tumors in hamsters upon the direct injection of viral DNA. We determined the transcriptional organization of the transforming region and compared it with that of the human adenoviruses. This analysis demonstrated that there are two independently promoted transcription units similar to the E1a and E1b regions of the human adenoviruses. The nucleotide sequence of the SA7 E1a region demonstrated considerable homology with the human adenoviruses, both in the sequences that regulate E1a expression and in the encoded polypeptides. The amino acid homology was reflected in the ability of SA7 to complement the growth of human adenoviruses mutant in the E1a region. Furthermore, we found two regions of amino acid homology unique to SA7 and the highly oncogenic human adenovirus 12.

Adenoviridae

Successful operation of a regional scheme for the maintenance of automatic analysers.

The main operational and financial aspects of the maintenance service provided by the West of Scotland Health Boards' Department of Clinical Physics and Bio-Engineering (DCPB) to the clinical chemistry laboratories in the region are described. The scheme, in operation since March 1976, covers all breakdown servicing and engineering preventive maintenance for Technicon Auto-Analyzer equipment valued at pounds 1 1/4 million in terms of direct replacement costs. The engineering team works closely with the laboratory staffs to ensure that the performance of the equipment is maintained to specification. The direct economies for the Health Boards through savings in maintenance contract charges total around pounds 60,000 per year. In addition, considerable sums have been saved by servicing, modifying, and constructing other instruments for the laboratories outwith the immediate remit of Technicon maintenance. Other economic and operational benefits which result from the scheme are commercially disinterested advice on equipment obsolescence and replacement, and redistribution between the laboratories of old but useful equipment to meet specific needs of the service in the region.

Autoanalysis