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Biomedical subjects

G D Allen

Publications and source records attributed to G D Allen.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

MODFIT: a pharmacokinetics computer program.

This paper presents a computer program, MODFIT, written in FORTRAN, primarily for use on the Digital Equipment Company VAX series computers for the mathematical analysis of concentration-time data. Drug data generated from biological fluids and tissues may be fitted by a variety of different models. For many models, parameter starting estimates are program generated prior to automatic nonlinear regression analysis using a modified Davidon-Fletcher-Powell algorithm. The output of results is extensive and plotting facilities are available. Explicit and differential equation models may be fitted to single dose data and simulations using all models (single or repeat dose) may be employed to generate drug concentration-time data with plotting output. The package has been tested on numerous data with no problems regarding local function minima. Some comparisons with existing programs have been made and MODFIT compares well with respect to robustness, efficiency, and ease of use.

Algorithms↗
PubMedDate not supplied

On the absorption of clavulanic acid.

It was not possible to computer fit oral clavulanic acid data using exponential or model equations incorporating a single exponential defining the absorption phase. Using the Loo-Riegelman method three phases of the absorption process became apparent, an initial slow phase, a more rapid phase and a final slow phase, contributing approximately 20, 70, and 5%, respectively, to the overall absorption process. Statistical moment analysis of clavulanic acid data following intravenous and oral solution administration gave mean values for the mean residence time, mean absorption time, and volume of distribution steady-state of 56 min, 43 min, and 14.01, respectively. Weibull analysis of the oral solution data gave mean values for lag-time and mean absorption time of 8 min and 46.8 min, respectively. Administration of clavulanic acid in a capsule formulation increased the lag-time before absorption but had no significant effect on the mean absorption time.

Administration, Oral↗
PubMedDate not supplied

Perceptual evidence against internal structure in American Sign Language syllables.

Syllables in spoken languages have been argued to have an internal structure which may cluster the consonants and vowels into subgroups. The most commonly used subgroups are the Onset (initial consonants) and Rhyme (vowel and remaining consonants), with the further possibility of dividing the Rhyme into Nucleus (the vowel and any on- or off-glides) and the Coda (the final consonants). Although linguistic debate continues about the exact formulation of such syllable models, the evidence is clear that listeners identify rhythmic beats at a particular point inside the syllable, namely at the release of the initial consonants into the following linguistically stressed vowels (referred to as the syllable peak, assumed to be part of the Nucleus). To determine whether such loci would be identified for syllables in American Sign Language, deaf native signers, hearing native signers, and hearing subjects unfamiliar with sign language were asked to tap to videotaped signed stimuli. Analysis of the tap locations in signed syllables revealed a relatively flat distribution across the syllable for all three groups and for individual subjects. The absence of syllable peak perception is discussed in relation to the motoric characteristics of sign production.

Adult↗
PubMedDate not supplied

Social influences on Pap smear screening frequency.

Incidence and mortality rates of cervical cancer among Native American women is two to five times that of comparable Whites. Social and cultural differences contribute to this problem. We studied thirty age 40 and older American Indian women, half of whom had obtained at least one Pap in the past three years, the other half of whom had not. We asked: Do the two groups differ in their attitudes concerning Pap tests and those with whom they interact concerning Pap tests? and: Do they interact differently with different social groups concerning Pap tests? Data were obtained from chart audits and Given's Health Belief Questionnaire. The groups did not differ as to who they discussed Pap tests with or whose opinions they respected. They respected healthcare professionals most, family/friends less, and co-workers/others least. These findings suggest that the advanced practice nurse has an opportunity to improve Pap screening rates in this population.

Adult↗