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Biomedical subjects

G Clemenson

Publications and source records attributed to G Clemenson.

11 recordsLinked to original sources
PubMed1982

The effect of sustained venous hypertension on the skin capillaries of the canine hind limb.

An increased number of skin capillaries has been found in human skin subjected to sustained venous hypertension. To investigate this observation, venous hypertension was produced in the hind limb of Greyhounds by fashioning an arteriovenous (AV) fistula between the femoral vessels. This caused an increase in the number of capillaries in the skin of the lower leg. The capillary permeability of normal legs and legs subjected to chronic venous hypertension was then studied by observing the movement of radioactive molecules from the plasma to the fluid within Guyton capsules. Fibrinogen, a large molecule, leaked out of the capillaries significantly faster in the limbs with a high venous pressure and an enlarged capillary bed. It is suggested that the increase in the size and permeability of the dermal skin capillaries secondary to prolonged venous hypertension is the cause of lipodermatosclerosis and venous ulceration.

Animals↗
PubMed1981

The relationship between the number of capillaries in the skin of the venous ulcer-bearing area of the lower leg and the fall in foot vein pressure during exercise.

The changes in foot vein pressure during exercise have been measured in 30 normal legs and 109 legs with varicose veins or postphlebitic changes and correlated with the number of capillaries visible in a histological section of skin from the ulcer-bearing area. There was a significant correlation between the inability of the calf pump to reduce foot vein pressure during exercise and the number of capillaries in the skin. It is suggested that the increased number of capillaries secondary to venous hypertension during exercise may be the prime cause of the nutritional abnormalities that eventually cause a venous ulcer.

Adolescent↗
PubMed1980

Is the postphlebitic leg always postphlebitic? Relation between phlebographic appearances of deep-vein thrombosis and late sequelae.

One hundred and thirty legs of 67 patients were examined 5-10 years after the patient had suffered a phlebographically proved deep-vein thrombosis. Forty-seven of the limbs were normal at the time of the phlebogram, 83 contained thrombus. There was little correlation between the phlebographic severity of the thrombus and the late symptoms and signs: 32% of the legs with no thrombosis had symptoms, while 33% of the legs which had suffered severe thrombosis had no symptoms. Postphlebitic symptoms were more common in legs with aging thrombus at the time of phlebography, but upper limit of the thrombus, the age of the patient, and preexisting symptoms did not affect the incidence of late sequelae. The development of a "postphlebitic leg" does not depend solely on the extent of the initial thrombosis and can apparently develop in the absence of thrombosis.

Female↗
PubMed1980

Venous lipodermatosclerosis: treatment by fibrinolytic enhancement and elastic compression.

The value of fibrinolytic enhancement with an anabolic steroid (stanozolol) combined with elastic stockings in treating venous lipodermatosclerosis was assessed in a six-month double-blind cross-over trial. Thirty-four legs of 23 patients in whom other treatments had failed were studied. The patients were randomly divided into two groups who were treated with either stanozolol plus elastic stockings or placebo plus elastic stockings for three months, and then vice versa. Treatment with or without stanozolol caused the area of lipodermatosclerosis to decrease, but the rate of healing when patients took stanozolol was double that when they took the placebo, and this was assumed to be biologically important. Stanozolol also reduced the incidence of extravascular fibrin detected in skin biopsy specimens. The elastic stocking with placebo produced significant decreases in leg volume, ankle circumference, and skin thickness. Stanozolol is valuable in treating intractable lipodermatosclerosis, giving relief of pain and reducing induration, inflammation, tenderness, and pigmentation.

Adult↗
PubMed1978

Vein surgery during defibrinogenation.

The effect of defibrinogenation on thrombosis after thrombectomy and on the patency of Dacron femoral vein grafts has been studied in dogs. In all experiments the defibrinogenation significantly reduced thrombosis. Bleeding from suture lines and through the Dacron prostheses was not increased.

Animals↗
PubMed1977

Doppler examination vs clinical and phlebographic detection of the location of incompetent perforating veins: a prospective study.

Accuracy in excess of 80% has been claimed both for ultrasound and for phlebographic localization of incompetent perforating veins (ICPVs). To test these claims, a blind prospective study was carried out to compare three methods of simultaneous ICPV detection with operative findings. ICPV localization on the medial side of 39 legs was made by clinical examination, ultrasound, and ascending phlebography, each by a different observer. The ICPVs were confirmed at operation. All three methods were comparable in their accuracy in predicting the anatomical site of ICPVs. Phlebography produced fewer (seven) and ultrasound more (49) false-positive results than clinical examination did. There was no specific advantage of ultrasound over clinical examination. The advantages of phlebography, (1) fewer unnecessary explorations and (2) assessment of the status of the deep venous sytem, must be weighed against its cost and morbidity.

Humans↗
PubMed1976

Effect of intravenous dextran 70 and pneumatic leg compression on incidence of postoperative pulmonary embolism.

The incidence of pulmonary embolism and deep vein thrombosis was measured in 50 matched pairs of patients undergoing common surgical procedures with preoperative and postoperative ventilation-perfusion lung scans and the fibrinogen uptake test. One patient in each pair was treated with intravenous dextran 70 and pneumatic leggings. The incidence of pulmonary embolism among the treated patients was significantly reduced from 24% to 8%, but the incidence of deep vein thrombosis was not significantly reduced (34% to 24%).

Dextrans↗
PubMed1974

Sequelae of an 125I-fibrinogen detected thrombus.

Forty-four patients who had a deep vein thrombosis detected with the fibrinogen uptake test were followed up three to four years later. The mild aching pains and ankle swelling that were present at the time of the thrombosis persisted or got worse in many, but there was no increase in the incidence of varicose veins. The minor self-limiting thrombosis detected with the fibrinogen uptake test should not be considered innocuous, for it can cause long-lasting symptoms.

Female↗
PubMed1974

Fibrinogen-detectable thrombosis in the legs and pulmonary embolism.

Thrombosis in the deep veins of the legs commonly follows surgical operations but is often undiagnosed. The fibrinogen uptake test is an aid to its detection. Perfusion lung scanning after injection of labelled macroalbumin aggregates has advanced the diagnosis of pulmonary embolism.Studies were carried out on 40 patients undergoing surgical operation to determine whether the results of the fibrinogen uptake test were correlated with those of ventilation-perfusion lung scanning. A statistically significant relationship was found: 18% of patients had small, clinically silent emboli.

Albumins↗
PubMedDate not supplied

The relationship between venous pressure and vein wall fibrinolytic activity.

Vein wall fibrinolytic activity has been shown to be greater in the arms than the legs and it has been suggested that this difference is related to the greater hydrostatic venous pressure in the leg. Vein wall fibrinolytic activity and foot vein pressure has been measured in 40 legs from 30 patients, 25 with uncomplicated varicose veins and 15 with lipodermatosclerosis. No statistically significant correlation could be demonstrated between vein wall fibrinolytic activity and measured foot vein pressure.

Arm↗