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Biomedical subjects

B J Morgan

Publications and source records attributed to B J Morgan.

48 records · Page 3Linked to original sources
PubMed1989

QUAD: a computer package for the analysis of QUantal Assay Data.

The computer package QUAD has been developed at the University of Kent, U.K. It is menu driven and written in Advanced BASIC. It runs on IBM PC compatible machines equipped with a suitable graphics facility such as CGA or simulated CGA. QUAD is available on a floppy disk, for a small handling charge. QUAD has four main functions: it performs a logit analysis of quantal assay data; it provides a flexible way of analysing the data, allowing dose transformations and providing alternative confidence intervals for EDp values; it produces a range of diagnostics for assessing the fit of models to data; it provides and fits two families of extended models, each containing the logit as a special case. The package makes use of the latest statistical research, and fitted models are displayed by means of the good graphics facilities available on microcomputers. This document describes the facilities available in detail, and provides and discusses, illustrations of the package at work. QUAD has been designed as a pilot package. Further additions and developments are planned and described later.

Animals↗
PubMed1988

Effects of age and training status on heart rate recovery after peak exercise.

Previous studies have shown that the kinetics of heart rate (HR) recovery are delayed in older individuals after exercise. This study was designed to determine whether this observation held when the variables of physical fitness and work intensity were controlled. Twenty male subjects were categorized into four groups (n = 5) according to age and fitness level (peak O2 consumption ml. kg-1.min-1): young trained (YT) 24 +/- 2 yr, 63 +/- 3 ml.kg-1. min-1; old trained (OT) 51 +/- 2 yr, 57 +/- 3 ml.kg-1.min-1; young untrained (YU) 25 +/- 3 yr, 44 +/- 2 ml.kg-1.min-1; old untrained (OU) 57 +/- 4 yr, 36 +/- 4 ml.kg-1.min-1. Bicycle ergometry exercise was performed in incremental stages to a maximally tolerated level of exertion, and HR was monitored continuously postexercise. Regression analysis of the fast (15-120 s) and initial slow (120-240 s) phases of recovery showed no effect of age on HR recovery when comparing YT vs. OT and YU vs. OU. Trained subjects, irrespective of age, demonstrated a significantly faster HR recovery than untrained subjects which was particularly marked during fast-phase recovery (P less than 0.005). These results indicate that the slower HR recovery previously reported in older subjects may be due to a failure to control for variables that influence recovery HR.

Adult↗
PubMed1985

A model for avian lung ventilation, and the effect of accelerating stimulation in Japanese quail embryos.

A simple stages model is proposed for the interval between the start of lung ventilation and the start of clicking in Japanese quail embryos. The model is extended to describe the effect of accelerating stimuli and is fitted to data sets from three different experiments. We see that the model provides a useful synthesis of the variety of results, and furnishes a framework for the analysis of further experiments.

Animals↗
PubMed1982

Effect of aerobic conditioning on cardiovascular response to isometric exercise.

The response to isometric handgrip exercise (IHE) and isometric quadriceps exercise (IQE) (30% maximum voluntary contraction held 3 min) was studied before and after 5 wk of aerobic training. Training exercises involved only the lower extremities. Seventeen healthy unconditioned males aged 21--35 yr were subjects. During training nine subjects received propranolol in doses that provided a high degree of beta-adrenergic blockade; eight received a placebo. All subjects were tested before training or drug and after training, 3--5 days off drug. With IGE after training, the placebo group had lower maximum heart rate (91 +/- 4 to 79 +/- 5 beats/min, P less than 0.05), systolic blood pressure (151 +/- 5 to 139 +/- 4 mmHg, P less than 0.05), and double product (heart rate x systolic blood pressure) (138 +/- 10 x 10(2) to 110 +/- 7 x 10(2), P less than 0.05). The response to IQE in the propranolol group was unchanged after training. Heart rate, systolic blood pressure, and double product with IHE was unchanged in either group after training. Aerobic conditioning can modify the hemodynamic response to isometric exercise. This effect is specific for the trained muscle group and is prevented by beta-adrenergic blockade.

Adult↗
PubMed1980

On modelling microbial infections.

Several models for the course of microbial infections during the incubation period are examined. Each model fits sore throat incubation data very well. Together with the lack of precision of the resulting parameter estimates, this suggests that incubation data alone are insufficient for elucidating the finer details of the development of diseases.

Bacteria↗