Use of Teflon stents for lymphovenous anastomosis.

The treatment of lymphoedema is difficult; conservative and surgical management show variable results. Lymphovenous anastomoses (LVAs) in experimental animals and patients give poor results in the treatment of primary lymphoedema and variable results in that of secondary lymphoedema. Conventional sutured LVAs were compared with anastomoses using polytetrafluoroethylene (Teflon) stents; 32 sutured and 21 stented LVAs were constructed in 16 rabbits with normal lymphatics. Anastomoses were assessed for quality and patency at 1-16 weeks by direct exposure; 27 cases were further assessed using lymphangiography. Patency in stented and sutured LVAs was 71 and 38 per cent at 1 week, and 38 and 8 per cent at 3 weeks, respectively. After 4 weeks all anastomoses were occluded. The quality of stented LVAs seemed to be higher than that of sutured LVAs. Stented LVAs are feasible and probably superior to conventional sutured LVAs. However, the patency of LVAs is of short duration because of the disadvantageous pressure gradient from lymphatics to veins, and this limits their clinical application.

Instrumental carbon monoxide dosimetry.

Modern technology for the ambient monitoring of carbon monoxide has been developed to produce a portable electrochemical instrument capable of the personal exposure to carbon monoxide. The performance characteristics of this device have been studied so that the unambiguous interpretation of field data could be performed. A study of the carbon monoxide exposure in a light manufacturing facility illustrate that effective dosimetry can be performed with expectations of accuracy typically better than +/- 15%, and that voluntary carbon monoxide exposures such as smoking were a significant contribution to the individual's exposure. Significant definition of the carbon monoxide exposure profile can be achieved with an instrument approach to the collection of the dosimetric data.

The velocity of lymph flow in the canine thoracic duct.

1. The velocity and pattern of movement of lymph in the thoracic duct of anaesthetized and conscious dogs has been studied by observing the movement of droplets of ultrafluid lipiodol in the duct.2. The velocity of flow when anaesthetized varied from 0.1-2.0 cm/sec, to 5.0 cm/sec when conscious.3. The pattern of flow was affected by respiration and the cardiac cycle. Most movement occurred at the end of inspiration.4. The duct of five autopsy preparations was perfused with saline to assess the volume and velocity of flow produced by the level of pressure gradients previously observed in the duct. These studies show that the small gradients (2-5 mmHg) observed during life are more than sufficient to produce the normal volume and velocity of flow measured. The mean resistance of the duct was 0.5 mmHg/ml. min.