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Biomedical subjects

P Carson

Publications and source records attributed to P Carson.

At least 19 recordsLinked to original sources

Topical use of human recombinant epidermal growth factor (h-EGF) in venous ulcers.

A great deal of interest has been focused recently on the potential use of synthetic polypeptide growth factors to stimulate healing of chronic wounds. In this pilot double-blind randomized study conducted at a single center, we used human recombinant epidermal growth factor (h-EGF) to treat 44 patients with venous ulceration of the lower extremities. An aqueous solution (10 micrograms/mL) of h-EGF was applied topically to the ulcers twice a day until healing occurred or for a maximum of 10 weeks. Patients were evaluated weekly for measurements of ulcer size and for the formation of granulation tissue suitable for grafting. Nine patients were excluded from efficacy evaluation because of protocol violations. Therefore, 35 patients (17 h-EGF, 18 placebo) were evaluable for efficacy, and 44 patients (22 h-EGF, 22 placebo) were available for safety. The median baseline ulcer size for all patients was 18.5 cm2, and was not significantly different between h-EGF and placebo group (12.9 cm2 versus 19.2 cm2, respectively, P = .27). By study end, six (35%) of h-EGF treated patients and two (11%) in the placebo group had healed completely (P = .10). Another 6 patients (2 of 17 h-EGF, 4 of 18 placebo; P = .50) developed healthy granulation tissue that was suitable for grafting. The median ulcer size reduction was 7% for h-EGF versus 3% for placebo per week (P = .29), and 73% versus 33% at study end (P = .32). No untoward side effects were related to the application of h-EGF. We conclude that topical application of h-EGF, in the dose and manner used in this study, was safe but failed to significantly enhance re-epithelialization of venous ulcers. However, a greater reduction in ulcer size and a larger number of healed ulcers with the use of h-EGF are encouraging results.

Administration, Topical

Congestive heart failure and converting enzyme inhibition: failure of current prognostic criteria for predicting subsequent renal insufficiency.

Angiotensin-1-converting enzyme inhibitors have an effective and established role in the treatment of patients with congestive heart failure. However, a small number of such patients will subsequently develop renal insufficiency. These patients may be identified prior to, or shortly after, commencement of therapy by recognized criteria. This report describes 4 patients with congestive heart failure who developed severe renal insufficiency secondary to either enalapril or captopril therapy in the absence of any currently recognized predisposing factors. One patient died.

Aged

Cardiovascular and neurohormonal effects of atrial natriuretic peptide in conscious dogs with and without chronic left ventricular dysfunction.

Atrial natriuretic peptide (hANP 4-28) was infused for 1 h (0.3 microgram/kg/min) in 11 normal awake dogs and seven awake dogs with chronic left ventricular dysfunction, induced 16 weeks earlier by repetitive DC shock. The responses were similar in the two groups and included decreases in arterial pressure (107-99 mm Hg), heart rate (83-72 beats/min), and cardiac output (3.6-2.8 L/min), without changes in right or left ventricular filling pressures. Systemic vascular resistance (SVR) tended to rise during the infusion and was significantly increased (2,847-3,442 dyn s cm-5, p less than .05) during the postinfusion recovery period. Regional blood flows (microspheres) during infusion revealed a decrease in skin and splanchnic flow. Despite the apparent vasoconstrictor effect, plasma norepinephrine (PNE), renin activity (PRA), and arginine vasopressin (AVP) levels all fell during ANP infusion. These data suggest that ANP exerts a cardioinhibitory effect, possibly similar to that of arginine vasopressin (AVP), and that the net systemic vasoconstrictor effect of ANP in these dogs is mediated by a complex interrelationship between direct vascular effects, neurohormonal inhibition, and central reflex activation.

Animals

Bacteria and gallstone nucleation.

This preliminary study reports for the first time that there might be a possible association between bacteria and the aetiology of some cholesterol calculi. The gall-bladder biles from 225 cholecystectomy patients underwent bacteriological and microscopic study. Cholesterol calculi from 13 patients (10.2%) were observed to be associated with gall-bladder bile profusely infected with at least one bacterial species that was shown to possess beta-glucuronidase activity, an enzyme that is thought to promote calcium bilirubinate precipitation in bile. Concomitantly, the associated gall-bladder bile was 'high' in calcium bilirubinate precipitation and the precipitate was also detected in the centre of the gallstones. Moreover, in approximately half of these patients (six of 13), the cholesterol gallstones' nuclear areas also contained calcium palmitate, which is also thought to be due to bacterial activity. The results also support the hypothesis that bacteria with active beta-glucuronidase (for example, Escherichia coli) can significantly influence the aetiology of brown pigment gallstones. In contrast, bacteria were observed to have no role in black pigment gallstone formation, as their associated gall-bladder biles were always observed to be sterile.

Adult

Assessing the psychological effects of an exercise training programme for patients following myocardial infarction: a pilot study.

During a study investigating physiological and other effects of an exercise programme for coronary patients, a questionnaire was administered. Preliminary analysis had suggested some improvement in the patients' morale, but in view of the possible relevance of a number of psychological variables it was decided to carry out further analysis on the available data. The coefficient of discrimination was computed for 32 patients. For 19 patients correlations were computed between scores on subjective fitness, symptoms, anxiety, interest in sex, if at work, age, weight, and workload achieved at a given heart rate. The questionnaire appeared to have satisfactorily high internal and external validity. Patients with a high 'morale' score tended to achieve a greater increase in workload over the course. Although cause and effect cannot be unequivocally assigned, the association is felt to be important, and research is continuing.

Anxiety

The electromechanical interval in normal subjects and after myocardial infarction.

The electromechanical interval (EMI) was measured in 25 normal males, 56 male patients with a myocardial infarction and 6 patients with a ventricular aneurysm. In the normal subjects the EMI was found to be unrelated to the heart rate but the isovolumic contraction time was inversely related to the heart rate. The EMI was increased after myocardial infarction but this increase did not occur in patientswho had a non-transmural infarction when they had not had any previous myocardial infarction. The increase was more marked in the patients with a ventricular aneurysm. It is suggested that the prolongation of EMI is due to areas of abnormal left ventricular wall movement and that this effect may be a useful aid to the diagnosis of ventricular aneurysm.

Adult