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Biomedical subjects

R H Grant

Publications and source records attributed to R H Grant.

16 recordsLinked to original sources
PubMed2001

Multi-waveband solar irradiance on tree-shaded vertical and horizontal surfaces: cloud-free and partly cloudy skies.

Irradiance measurements of short wave (SW), photosynthetically active (PAR), ultraviolet-A (UVA) and ultraviolet-B (UVB) solar radiations were made on horizontal and vertical surfaces in the shade of trees under cloud-free and partly cloudy skies. All measurements were referenced to the irradiance of a horizontal surface above the canopy. For horizontal shaded surfaces under cloud-free skies, the values of the ratio (Rh) of below- to above-canopy horizontal irradiance were similar for the UVA and UVB wavebands and for the SW and PAR wavebands. However, Rh for the UV wavebands differed from that for the PAR and SW wavebands. Overall, values of Rh in the shade typically varied as PAR < SW << UVA < UVB. The irradiance ratios for vertical surface in the shade typically varied as UVB > UVA = SW > PAR. In absolute terms, UVB irradiance (Ih) on tree-shaded horizontal surfaces increased relative to a cloud-free sky when a translucent cirroform cloud was in front of the sun, but decreased when the cloud was in a region of sky away from the sun. Translucent cirroform cloud cover also tended to decrease the UVB irradiance (Iv) for a shaded vertical surface (either facing the sun or south) relative to that under cloud-free skies, regardless of where the clouds were in the sky. In all other wavebands the shaded Ih and Iv increased under translucent cirroform cloud cover relative to cloud-free skies, regardless of where the clouds were in the sky.

Humans↗
PubMed1994

Aerosol transmission of a viable virus affecting swine: explanation of an epizootic of pseudorabies.

A Gaussian diffusion model was applied to an epizootic of pseudorabies in ten swine herds located in Decatur County, Indiana, USA to test the hypothesis that the virus can be spread via aerosol. The epizootic occurred during January to March, 1988, spreading through ten farms across an area of about 150 km2. The model included a receptor component that provided an estimate of viruses received by the pig within an enclosed barn. Results show that the diffusion model can explain the spread of the virus during the epizootic for all nine farms to which the virus spread.

Air Microbiology↗
PubMed1991

Epizootic of pseudorabies among ten swine herds.

An epizootic of pseudorabies in 10 swine herds located near Greensburg in Decatur County, Indiana was investigated. Records of Decatur County swine herds previously quarantined because of pseudorabies were obtained. For the 1988 epizootic, clinical findings were considered, location of each of the 10 swine herds in relation to the other herds was determined, and potential fomites were considered. Meteorologic data prior to, during, and after the epizootic were obtained, correlated, and analyzed. A source-receptor model, based on wind direction and speed data, was used to determine whether weather conditions in the Greensburg area enhanced the potential for aerosol spread of pseudorabies virus between herds. On the basis of lack of other modes of spread of pseudorabies and on meteorologic and source-receptor data, aerosol transmission of pseudorabies virus between the 10 herds was probable.

Air Microbiology↗
PubMed1988

Phenytoin-induced gum hypertrophy in patients with epilepsy.

One hundred and eight patients who had been taking phenytoin for a year or more, either alone or in combination with other drugs, were examined for gum hypertrophy by three observers independently. Approximately 90% of the patients showed either mild or no gum hypertrophy and severe swelling occurred in only 1%. The observed standards of oral hygiene were extremely poor. A tendency for higher serum phenytoin levels to be associated with greater gum hypertrophy was observed. Because the condition was causing no problems in over 90% of patients, it is considered that gum hypertrophy per se should not deter a physician from using phenytoin in the treatment of epilepsy.

Adolescent↗
PubMed1978

Individual variation in daily dosage requirements for phenytoin sodium in patients with epilepsy.

1 Ninety adult patients receiving phenytoin sodium were studied prospectively in an epileptic centre. Serum concentrations of phenytoin under steady state conditions were measured by gas liquid chromatography. When clinically indicated the daily dosage rate was adjusted by 50 mg steps until a serum concentration of 10--20 mg/l was produced. 2 Concentrations within the above range were obtained in 50 patients; the required dosage rate varied from 200--500 mg/day. Twenty-five clinical, biochemical and haematological attributes were recorded for each patient and tested for correlation with dosage requirement. 3 The dosage requirement correlated most strongly (r = 0.57, P less than 0.001) with body surface area. This relationship (approximately 200 mg/day per m2) accounted however for only one third of the total dosage variance. 4 Amongst 18 patients receiving simultaneous treatment with phenobarbitone, the effective plasma clearance of this drug taken in conjunction with body surface area accounted for a significantly greater proportion of the total dosage variance. Multiple regression analysis failed to reveal other, more widely applicable predictors of individual phenytoin dosage requirements.

Adult↗
PubMed1977

Family and self-help education in isolated rural communities.

Family and self-help education courses were developed to promote better personal health through more appropriate utilization of health services in underserved rural areas. Instructional target areas were health problems of young children and the elderly and emergency situations. Objectives and evaluation criteria were formulated after consultation with representatives of participating communities and expert advisors. Community advisory committees were identified or created to supervise program development and implementation. Local instructors were utilized and developed specific course content. An evaluation of one course showed that knowledge and decision-making skills significantly improved for participants.

Achievement↗
PubMed1970

Folic acid in folate-deficient patients with epilepsy.

A double-blind trial using folic acid 15 mg. daily and identical placebo was carried out in 51 epileptic patients having a serum folate level below 3.6 ng./ml. Treatment was for a minimum of six months and in 41 patients was for more than one year. There were no significant changes in the frequency of seizures, behaviour, and personality, or in a number of cognitive functions.

Adolescent↗