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Biomedical subjects

D Porter

Publications and source records attributed to D Porter.

At least 55 records · Page 3Linked to original sources
PubMed1982

Rapid method for determining antimicrobial susceptibility of Haemophilus influenzae.

A method was developed to determine the susceptibility of Haemophilus influenzae to ampicillin, cefamandole, and chloramphenicol by using the MS-2 system (Abbott Laboratories) for determining minimum inhibitory concentrations (MIC). The MS-2 results for 132 strains of H. influenzae were compared with the results of agar disk diffusion, agar dilution, and beta-lactamase tests. Twenty-four strains (18.2%) of H. influenzae were resistant to ampicillin by the agar dilution method, as opposed to 25 strains by the MS-2 method. For a beta-lactamase-negative strain, the agar dilution MIC was 4 micrograms/ml, and the MS-2 MIC was 16 micrograms/ml. Twenty-one strains produced beta-lactamase; two beta-lactamase-negative strains were resistant by MS-2, agar dilution, and agar disk diffusion. In addition, one beta-lactamase-negative strain, for which the agar dilution MIC was 32 micrograms/ml and the MS-2 MIC was 16 micrograms/ml, was sensitive by agar disk diffusion. Overall, the MS-2 method compared favorably with the agar dilution method for determining the MIC of ampicillin, cefamandole, and chloramphenicol for H. influenzae.

Ampicillin↗
PubMed1979

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↗
PubMed1977

Daily relaxation response breaks in a working population: I. Effects on self-reported measures of health, performance, and well-being.

An experiment conducted at the corporate offices of a manufacturing firm investigated the effects of daily relaxation breaks on five self-reported measures of health, performance, and well-being. For 12 weeks, 126 volunteers filled out daily records and reported bi-weekly for additional measurements. After four weeks of baseline monitoring, they were divided randomly into three groups: Group A was taught a technique for producing the relaxation response; Group B was instructed to sit quiety; Group C received no instructions. Groups A and B were asked to take two 15-minute relaxation breaks daily. After an eight-week experimental period, the greatest mean improvements on every index occurred in Group A; the least improvements occurred in Group C; Group B was intermediate. Differences between the mean changes in Groups A vs C reached statistical significance (p < 0.05) on four of the five indices: Symptoms, Illness Days, Performance, and Sociability-Satisfaction. Improvements on the Happiness-Unhappiness Index were not significantly different among the three groups. The relationship between amount of change and rate of practicing the relaxation response was different for the different indices. While less than three practice periods per week produced little change on any index, two daily sessions appeared to be more practice than was necessary for many individuals to achieve positive changes. Somatic symptoms and performance responded with less practice of the relaxation response than did behavioral symptoms and measures of well-being. (Am. J. Public Health 67:946-953,1977)

Adult↗
PubMed1977

Collection of a clean voided urine specimen: a comparison among spoken, written, and computer-based instructions.

In an effort to compare different methods of instructing patients, 99 women 18-25 years of age were given computer, spoken, weitten, or no instructions for the collection of a clean voided urine specimen. The group who received computer instructions was the most uniform in its performance (P less than 0.002, F-test) and reported the fewest procedural problems (P less than 0.02, Fisher test). In addition, this group had fewer contaminating bacteria than the group who received written instructions (P less than 0.03 , Mann-Whitney test). The group who received no instructions had more bacteria (P less than 0.0001, Mann-Whitney test) than any of the other groups. The effectiveness of the computer instruction was probably related to numerous attributes, including the individualized quality of the dialogue, self-pacing, self-testing, and privacy.

Adolescent↗
PubMed1976

A computer-based dietary counseling system.

A computer-based dietary counseling system is described. Designed to interact directly with patients, the program interviews people about their dietary behavior and plans with them a weight-reducing diet of approximately 1,500 kcal. In a preliminary trial, twenty-five volunteers gave critical commentary en route through the interviews. The results provided insight into the process of dietary interviewing by computer and helped in the preparation of an experimental study (10). It is our hope that a revised and expanded version of the program will be helpful to both patients and nutritionists in the management of a variety of clinically important dietary problems.

Computers↗
PubMed1976

Dietary interviewing by computer. An experimental approach to counseling.

A computer-based dietary counseling system was tested by sixty-four volunteers from the Boston area. Most of the patients seemed to benefit from their interaction with the computer, and the two participating nutritionists frequently found that the program was useful as an antecedent to their own one-to-one sessions with the patients.

Adult↗
PubMed1975

Interaction of gamma-ray and neutron effects on the proliferative capacity of Chinese hamster cells.

The loss of reproductive capacity of Chinese hamster cells has been studied using 60Co gamma-rays and DT neutrons singly or combined in fixed proportions. Surviving fractions were measured down to 2 times 10-4. Interaction between the effects produced by neutrons and gamma-rays in the mixed irradiations has been demonstrated. The results are compared with those predicted by the cellular inactivation model developed by Katz and co-workers from their delta-ray theory of track structure.

Animals↗
PubMed1975

The response of the ferrous sulphate dosemeter to neutrons.

A semi-empirical method of calculating G-values for the ferrous sulphate dosemeter irradiated by neutrons up to 18 MeV has been developed. It utilizes published charged particle G-values along with particle spectra calculated for mono-energetic neutron interactions with the dosemeter medium. All available G-value measurements with neutrons have been evaluated and compared with values predicted by this method. The agreement was excellent for DT generator and cyclotron neutron beams in which the neutron spectra had been accurately determined. However, the predictions could not be completely confirmed for lower energy neutrons becuase of the large experimental uncertainties in the measured G-values and the lack of detailed information on the neutron spectra.

Evaluation Studies as Topic↗
PubMed1975

A novel fast neutron dosemeter based on fission chambers. Part I: Principles of operation and theoretical response in neutron therapy radiation fields.

A novel method is proposed of accurately measuring fast neutron doses of interest in radiotherapy. The technique, which utilizes calculated neutron fluence-to-kerma conversion factors, is based upon the combination of measurements with calibrated neptunium-237 and uranium-238 pulse fission chambers to obtain a response which matches the variation of kerma with neutron energy. The theoretical performance of a practical instrument has been assessed for a variety of neutron spectra to evaluate the spectrum dependence of the dosemeter. The overall systematic uncertainty using this absolute method of determining the neutron dose under charged particle equilibrium conditions is comparable to that encountered with ionization chamber techniques.

Hot Temperature↗