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Biomedical subjects

J S Whamond

Publications and source records attributed to J S Whamond.

16 recordsLinked to original sources
PubMed1987

Effects of haemorrhage on wound strength and fibroblast function.

The impairment of healing in laparotomy wounds in rats with compensated oligaemia has been studied in two parallel investigations. Animals bled 1 ml/100 g body weight (bled) were compared with unbled animals undergoing the same operation (control). Firstly, wounds were assessed after 22 days for strength of skin and muscle layers (11 control: 9 bled). Both layers were significantly weaker in bled animals; by 36 per cent for skin (P less than 0.02) and by 22 per cent for muscle (P = 0.02). Secondly, wound fibroblast function was assessed after 10 days by quantitative histology and autoradiography (30 control: 31 bled). There were no significant differences between the two groups for fibroblast density, replication ([3H]thymidine), or general protein synthesis ([3H]leucine). Bled animals had less dense collagen packing by 21 per cent (P less than 0.01), but 33 per cent more incorporation of ([3H]proline) by fibroblasts (P less than 0.01) compared with control animals. The effect of compensated oligaemia on wound healing is more marked in skin than in muscle; it appears to be a specific increase in collagen turnover with the increase in reabsorption exceeding that in synthesis.

Animals↗
PubMed1977

The assessment of haemodynamic function of diseased and prosthetic heart valves in patients.

The paper deals with reasons why current methods of assessing the resistance to flow offered by heart valves in patients are unsatisfactory. A theoretical and simulation study suggested that a measure of energy or power loss per unit flow was likely to be of more use and subsequent clinical investigations have confirmed this. The computation can be readily carried out in a hard-wired parallel hybrid module for operating theatre or catheter laboratory use.

Electric Conductivity↗
PubMed1975

Reliability of human and machine measurements in patient monitoring.

In a study on 29 patients for 152 hours a continuous monitoring system has been shown to have a reliability of 90.53% for pulse rate and 82.20% for arterial blood pressure, but for approximately half of the period of unreliable monitoring a not obviously artifactual reading was being displayed. The relevance of this to possible incorrect diagnosis and management is discussed. The monitor and a nurse using traditional chart keeping methods gave equivalent charts with respect to average levels and trends, but the monitor assisted chart showed a much greater variability. The latter tended to obscure underlying trends and render clinical diagnosis from the chart more difficult.

Blood Pressure↗
PubMed1975

Short-term variability of pulse rate and blood pressure in cardiac surgery patients.

The magnitude and mathematical nature of short-term variations of pulse rate and mean arterial blood pressure has been studied in 27 post-operative cardiac surgical patients over a continuous period of 200 min in each case. Similar variability was observed in all patients. Short-term variations were composed predominantly of a series of rhythmic changes ranging from one synchronous with respiration to others between 2 and 5 min in cycle length. There was consistent variance of the beat-by-beat values for both variables about a continuously updating 5 min mean. The average standard deviation was 3.75 beats/min for pulse rate and 0.48 kPa (3.64 mm Hg) for mean arterial blood pressure. For both variables the distribution about the 5-min mean did not differ significantly from a normal distribution in 50 out of the 54 records. These findings have implications for the reproducibility of current methods of estimating mean pulse rate and blood pressure, and the change necessary before two estimates may be regarded as significantly different. The results are applicable both to the interpretation of Ward Charts by medical staff and to automated monitoring systems.

Adolescent↗