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Biomedical subjects

V A Spence

Publications and source records attributed to V A Spence.

48 records · Page 3Linked to original sources
PubMed1982

Why smoke fewer cigarettes?

Sixteen volunteers were tested when smoking their own brand of cigarettes normally and when smoking half their usual number of cigarettes. While smoking half their usual amount the subjects changed their inhalation behaviour. Over this period the percentages of carboxyhaemoglobin were not significantly different from steady-state values where plasma nicotine concentration rose significantly. With the reduction in cigarettes there were significant falls in haemoglobin concentration, packed cell volume, and red cell count. These findings suggest that the advice given to patients to smoke fewer cigarettes should be accompanied by a warning against increasing inhalation. Patients who say that they have reduced their smoking but who have unaltered carboxyhaemoglobin concentrations should not be discredited.

Adult↗
PubMed1981

Colonic mucosal-submucosal blood flow and the incidence of faecal fistula formation following colostomy closure.

Fistula formation following closure of a colostomy occurs most frequently when closure is carried out within the first few weeks of construction and may be related to an impaired local microcirculation. Using a recently described method for measuring colonic mucosal-submucosal blood flow, the variations in local flow which occur during the first month after colostomy construction were determined in 8 patients. Mean blood flow increased from 6.9 +/- 1.8 ml min-1 100 g-1 (s.d.) at 7 days to 31.1 +/- 12.5 ml min-1 100 g-1 (s.d.) at 28 days. In a further 40 consecutive patients undergoing colostomy closure, blood flow measurements were made before operation. Eight patients developed a faecal fistula, and in 5 of these patients mucosal-submucosal blood flow was found to be less than 15 ml min-1 100 g-1. In every successful colostomy closure blood flow was greater than 15 ml min-1 100 g-1. This study provides evidence that a subnormal blood flow is one of the factors associated with fistula formation following the operation of colostomy closure.

Colon↗
PubMed1981

Changes in human colonic mucosal-submucosal blood flow after body surface cooling.

Mucosal-submucosal blood flow in the human colostomy was measured by a radioisotopic washout technique. Changes in blood flow were recorded in 10 subjects after peripheral vasoconstriction evoked by surface cooling of the body. Accompanying the vasoconstriction was a rise in mucosal-submucosal blood flow of approximately 40%. An interpretation of the blood flow changes and the associated alterations in mean arterial blood pressure provide evidence for vasomotor and local regulatory control in the colostomy microcirculation. We believe, therefore that the colostomy is a suitable preparation for studying the human colonic microcirculation.

Cold Temperature↗
PubMed1981

Amputation of the ischemic limb: selection of the optimum site by thermography.

This report describes the value of infrared thermography in assessing the optimum level of amputation of an ischemic limb. Interpretation of thermograms and the factors that can significantly alter the thermal image of the lower limbs are detailed. Results from 104 patients demonstrate that the thermographic method is a reliable indicator of the level of a major limb amputation. A rationale for the inadequacy of the method when attempting to determine the outcome of a partial foot amputation is considered.

Adult↗
PubMed1980

The measurement of colonic mucosal-submucosal blood flow in man.

1. A method is described for the measurement of colonic mucosal-submucosal blood flow in man, by studying surgically created colostomies. 2. A local radioisotopic clearance technique utilizing a stable preparation of [125I]4-iodoantipyrine is employed. The indicator is injected directly into the colostomy under study and its gamma emission is recorded by a scintillation detector. 3. A radioautographic study was carried out at laparotomy in humans to facilitate the interpretation of the recorded washout curves. This demonstrated that the tracer was cleared from both the mucosa and submucosa throughout the period of study. 4. Mucosal-submucosal blood flow was calculated according to Kety (1949) from the monoexponential clearance curves obtained, and amounted to 31.7 +/- 11 ml./min. 100 g (S.D. of an observation, n = 30). 5. The results from two consecutive measurements in seventeen patients showed that the mean change between first and second readings was not significant (t test). In addition the between-patient variation (12.2) was significantly greater than the within-patient variation (2.6) for consecutive recordings (F test; P less than 0.01). 6. The within-patient between-days variation (12.9; n = 10) was found to be similar to the between-patient variation. 7. It is concluded that the technique permits measurement of local colonic blood flow in man and by consecutive measurements, it may be used to evaluate local changes in blood flow following reflex or pharmacological stimulation.

Autoradiography↗
PubMedDate not supplied

Serum thiocyanate levels in subjects who halve their cigarette consumption.

The serum thiocyanate levels were measured in sixteen volunteers who smoked their own brands of cigarettes normally. When their cigarette consumption was reduced by half, the serum thiocyanate levels remained unaltered. The most likely explanation of this finding is that the volunteers changed their inhalation behaviour.

Adult↗