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Biomedical subjects

R D Leach

Publications and source records attributed to R D Leach.

At least 19 recordsLinked to original sources
PubMed1991

Choline inhibition of prothrombin activation.

A computer-interfaced spectrophotometric kinetic assay for prothrombin activation was developed, coupling the production of thrombin to a thrombin-specific amidolytic chromogenic reaction. As thrombin accumulated initially at constant velocity, the simultaneous release from S-2238 of pNA conformed to an acceleration function. Adherence to the acceleration function of the temporally increasing A400 of pNA was evaluated after transforming the data into linear format which permitted linear regression analysis. High correlation coefficients, routinely greater than 0.99, verified linearity of thrombin production in individual assay mixtures. As prothrombin concentrations were varied, factor Xa exhibited Michaelis-Menten kinetics. Added choline produced a pattern of mixed-type inhibition. Replots of LB slopes and intercepts versus choline concentration gave apparent Ki and Ki' values (mM): 22 +/- 3 and 48 +/- 7 without factor Va, 25 +/- 4 and 41 +/- 4 with factor Va.

Aspirin↗
PubMed1989

Sutures for inguinal herniorrhaphy--a comparison of monofilaments with PTFE.

Polybutester (Novafil, Davis & Geck) and expanded polytetrafluoroethylene PTFE (Gore-tex, W L Gore) were compared with nylon (Ethilon, Ethicon UK) for elective inguinal herniorrhaphy. PTFE had the best handling characteristics, but is expensive, and increased wound sepsis attended its use. Polybutester had significantly better handling characteristics, and is an attractive alternative to nylon for hernia repair.

Adult↗
PubMed1987

Effect of a surgical day unit on waiting lists.

The effect of a surgical day unit (SDU) on the waiting lists of a busy district general hospital is reported over a 4-year period. During this time, 18 (15%) of the general surgical beds were closed for financial reasons. A real saving rather than an apparent one is reported due to the work expansion in the SDU.

Ambulatory Surgical Procedures↗
PubMed1986

The clearance of 125I-labelled fibrin from the subcutaneous tissue of limbs with lipodermatosclerosis.

The clearance of radioactive fibrin from the subcutaneous tissues has been measured in the rat and in the limbs of normal subjects, patients with varicose veins, and patients with lipodermatosclerosis. The animal experiments showed that the most effective way of producing a subcutaneous deposit of fibrin was by the simultaneous injection of labelled fibrinogen and thrombin. The clearance of these clots was delayed when fibrinolysis was depressed with epsilon-aminocaproic acid. Clearance of subcutaneous fibrin in man was significantly slower in the arms of patients with varicose veins and lipodermatosclerosis. Similarly clearance in the legs of patients with lipodermatosclerosis was significantly slower than that of the normal subjects and those with uncomplicated varicose veins. The clearance of fibrin from the legs of patients with lipodermatosclerosis was significantly slower than the clearance from their arms but there was no difference between arm and leg clearance in the normal subjects and those with uncomplicated varicose veins. The patients with lipodermatosclerosis had a significantly longer dilute blood clot lysis time. The inability to clear subcutaneous fibrin may be an aetological factor of lipodermatosclerosis.

Aminocaproates↗
PubMed1985

Effect of venous hypertension on canine hind limb lymph.

The effect of acute and chronic venous hypertension on the lymph draining from the hind limb has been studied in 10 dogs. Acute venous hypertension was produced by venous occlusion, and chronic venous hypertension by fashioning an arteriovenous fistula in the groin. Acute venous hypertension trebled the lymph flow and doubled its fibrinogen concentration thus increasing the net transport of fibrinogen across the interstitial space by 600 per cent. Chronic venous hypertension had a similar effect and caused the appearance of alpha-2-antiplasmin in the lymph. The fibrinolytic activity of the lymph did not change significantly in either group of experiments. These results suggest that the deposition of interstitial fibrin seen in the skin of the postphlebitic limb is related to an increased concentration of interstitial fluid fibrin, and to the appearance of the fibrinolytic inhibitor, alpha-2-antiplasmin, without a concomitant increase of fibrinolytic activator.

Acute Disease↗
PubMed1985

The changing trend in prostatectomy in a district general hospital.

The results of 600 prostatectomies performed at Kingston Hospital are reviewed with particular reference to morbidity and mortality. The indication for surgery was prostatism in 61% of patients and retention in 34.5%. Transurethral resection (TUR) was performed in 65.5% of the operations. The mean postoperative stay for TUR was 6 days but for open operation 10 days. The overall complication rate including urinary tract infections was 14.8%, with an overall mortality of 1.3%. The results show the trends and improvement in service achieved since an earlier report of 600 cases published in 1979.

Aged↗
PubMed1984

Venous ulceration, fibrinogen and fibrinolysis.

The effect of long and short-term venous hypertension upon lymph fibrinogen concentrations was studied in an attempt to explain the peri-capillary deposition of fibrin reported in patients with post-phlebitic syndromes. The clearance of radioactive fibrinogen/thrombin clots from the subcutaneous tissues of rats and human volunteers was also studied. Both long- and short-term venous hypertension were found to increase fibrinogen transport across the interstitial space by more than 600%. Not only was there evidence of fibrinolytic activity in the lymph but after long-term venous hypertension alpha 2 antiplasmin activity was also detectable. Skin biopsies from the venous hypertensive ankles showed deposition of interstitial fibrin. The clearance of radioactive fibrinogen/thrombin clots from the subcutaneous tissues of the rat was found to be delayed if the rats were given epsilon amino caproic acid but it could not be increased with stanozolol. In human subjects it was found that patients with lipodermatosclerosis had delayed clot clearance and retarded blood fibrinolytic activity when compared with normal volunteers and patients with uncomplicated varicose veins. The principle cause why tall men are more subject to ulcers than short men, Dr Young conceived to be then length of the column of blood in their veins; which by its pressure, renders the legs less able to recover when hurt by any violence.

Aminocaproic Acid↗
PubMed1982

The aetiology of perirectal sepsis.

Organisms that are present in the normal faecal flora, especially Bacteroides fragilis, were isolated significantly more often from perirectal abscesses associated with a fistula. Other organisms similar to those associated with infection of obstructed apocrine glands at other sites were isolated from abscesses without fistulas. These findings suggest that perirectal abscesses with and without fistulas may have a different aetiology and that appropriate bacteriological investigation may give an indication of the presence of an unsuspected fistula and thus provide useful guidance to the correct surgical management of the patient. Staphylococcus aureus and other skin organisms were found less frequently than in previous studies on perirectal sepsis and were equally common in cases with or without a fistula-in-ano.

Abscess↗
PubMed1982

The aetiology of scrotal sepsis.

The clinical findings and bacteriology of 30 abscesses of the scrotum and described. Anaerobic organisms were found in 27 abscesses (90 per cent), and in 3 cases in which they were not, the patients were receiving metronidazole at the time of drainage. Multiple anaerobic species were isolated, predominantly those found as commensals in the oropharynx and genital tract. "Gut specific' Bacteroides spp. were very uncommon and were found only in patients with necrotizing fasciitis. It is suggested that the severity of some infections, particularly after scrotal surgery, is associated with thrombosis of the scrotal vessels.

Abscess↗