No abstract

SUMMARYSixteen ulnar arteriovenous fistulae have been performed in 1 1 patients. Three immediate thromboses occurred in the same patient. Six late thromboses were observed: 2 after kidney transplantation and 4 after haemodialysis. Seven out of the 10 patients in whom the fistula was used were dialysed adequately from 5 weeks to 15 months. No adverse effect owing to the fistula was noted.THE creation of an arteriovenous fistula in the forearm allows haemodialysis to be carried out regularly and easily by simple venepuncture (Brescia, Cimino, Appel, and Hurwich, f966). The details and advantages of this technique have been described in many papers

A histological and radioautographic examination of 11 autologous fascia lata heart valves used in man is described. There was a significant decrease, exponential with time, in the number of fibroblasts per unit volume (P<0 001). The collagen bundles were grossly disorganized and separated, suggesting a breakdown of the cross-linkage in the tissue. Redundant connective tissue on the surface of the valve cusp became oedematous and contained many trapped cells. A pseudoendothelium was formed within 10 days. Incorporation of tritium-labelled thymidine in the nuclei of the fibroblasts showed a sixfold reduction over 9 to 12 weeks following implantation, suggesting a failure of metabolism in these cells. The suitability of fascia lata for human heart valve replacement is discussed.The construction of heart valve substitutes from autologous fascia lata using differing techniques has now become a well-established routine in many centres (Senning, 1967;Ionescu and Ross, 1969;Ionescu, Ross, Deac, Grimshaw, Taylor, Whitaker and Wooler, 1970). Probably the technique most commonly used is one where the fascia lata is sewn on to a supporting threepronged stent for ease of fabrication and insertion (Ionescu and Ross, 1969).In a recent review of 76 patients who had undergone mitral valve replacement with a framemounted fascia lata valve, concern was expressed at the finding of contraction of the cusps of three of these fascia lata valves, with ensuing incompetence (Lincoln, Balcon, Emanuel, McDonald, Muir, Ross, Somerville, and Taylor, 1970). Because of these findings, a study was carried out on frame-mounted fascia lata valves which, for a variety of reasons, had been removed from patients in whom they had been inserted. MATERIAL 1. Fascia lata taken from two patients, A and B, who were undergoing cardiac surgery was made into routine histological sections and stained with haematoxylin and eosin, and these were used as controls. From 11 patients, C to M, sections of valves which had been inserted for periods of time ranging from two days to 32 weeks were also made into histological sections and stained with haematoxylin and eosin.2. Fascia lata from patient B was divided into two parts. One part was immediately fixed in 10% formalin in 0-1 M phosphate buffer, and the other part was left unfixed. Parts of both were prepared for radioautography. Fascia lata from patient I, who had had a valve in situ for nine weeks, and from patient J, who had had a valve in situ for 12 weeks, was prepared for radioautography. The time lapse which occurred between removing the fascia lata from the patients and its special preparation for these studies never exceeded 30 minutes. METHODSRadioautography can give information regarding the growth rate of cells by their ability to incorporate tritium(H3)-labelled precursors of DNA.A modification of the radioautographic technique of Kopriwa and Leblond (1962) was used. This technique is as follows:1. Samples of fascia lata were incubated at 37°C for 48 hours in Eagles Minimum Essential Medium to which ...