Signet-ring cell cancer represents a rare but distinctive primary neoplasm of the large bowel. It is frequently diagnosed in an advanced tumor stage, thus showing an overall poorer prognosis than nonsignet colorectal carcinoma. Usually only palliative surgery is possible. A high incidence of peritoneal seeding and a low incidence of hepatic metastasis is characteristic of signet-ring cell cancer.

These results support the hypothesis of an association between low selenium level and advanced tumor disease. From our data, it cannot be decided whether this phenomenon is more likely to be a consequence or a causative factor for development and course of the disease.

The substitute "valve" operation by Technique II designed to overcome reflux in the popliteal vein was performed on 105 patients (119 limbs) with deep venous incompetence of the lower limb. There was a five-year follow-up on 101 of them (115 limbs) after operation by Technique II. Results were assessed clinically, by Doppler ultrasound, by venous pressure measurements, and by phlebography. Clinical improvement in 108 of 115 limbs was associated with a decrease in ambulatory venous pressure and prolongation of refilling time with interruption of the popliteal reflux by Doppler (96 limbs) and with phlebographic evidence of a functioning substitute "valve."

The substitute "valve" operation by Technique II using a silicone tendon designed to produce a valve-like mechanism on the popliteal vein is described. The results obtained in 55 limbs with chronic venous insufficiency due to reflux in the deep veins have been assessed by phlebography and by measurements of ambulatory venous pressure before and one week after the operation; 23 limbs were followed up two years after the operation. Clinical improvement in 50 of 55 limbs was associated with reduction in the ambulatory venous pressure and with phlebographic evidence of a functioning "substitute valve." After using the Doppler ultrasound the abolition of the popliteal reflux in 11 limbs after substitute valve operation by Technique II was studied; they had had a marked popliteal reflux and a high ambulatory venous pressure before the operation.

Investigation of the deep venous system of the lower limb must mainly aim to elucidate its capabilities. Because deep venous incompetence is necessarily con nected with a popliteal reflux accounted for by valvular incompetence of the popliteal vein, its presence must be clarified. An isolated valvular incompetence of the femoral vein without popliteal incompetence is of no clinical significance and should be disregarded. Only patients with popliteal reflux detected by Dop pler ultrasound require a further examination by venous pressure measure ments and by phlebography. An operation in the deep veins is admissible only when a popliteal reflux > 40%, and ambulatory venous pressure > 60 mmHg, a refilling time < 15 sec, a venous insufficiency > 20%, and a patency or recanalization of the deep venous > 70% have been confirmed. A correlation between venous pressure and Doppler recordings has been done.