The microvascular anatomy of the calcaneal tendon was investigated in cadaver tendons by injection of barium sulphate and indian ink and a quantitative study of intratendinous blood supply was made, using a computer-assisted image analysis system. There was a reduction in both the number and the mean relative area of vessels in the mid-section of the tendon. This area of reduced vascularity may be of significance in the pathogenesis of rupture.

Over a period of twelve months, 116 cases of mallet finger were allocated randomly to treatment with either a Stack or Abouna splint. The two splints were equally effective, producing a cure or a significant improvement in approximately 50% of cases. However, the Stack splint was much preferred by the patients, who found it more comfortable, more robust and easier to keep clean.

No abstract

Modern casting materials are becoming available in an increasing and bewildering variety. A series of tests has been devised to investigate the properties of these materials. They have been tested for strength, flexibility, lamination, fatigue life and radiolucency. Their properties have been compared with those of plaster of Paris in order that the role of the newer materials can be defined. It is suggested that the tests described might form the basis of a standard from which user trials could be designed to appraise the value of these materials in clinical practice.

The effects of ion substitution, inhibitors and variations in transmural p.d. on the movements of sodium and chloride across an in vitro preparation of rat gastric mucosa have been studied. The tissue maintained net steady‐state transport of sodium in the mucosal‐to‐serosal direction in the absence of transmural gradients of electrochemical potential. Sodium transport was independent of the presence of chloride, and was abolished by 1 X 10(‐5) M‐amiloride. The inhibitor produced a decrease in short‐circuit current equivalent to the depression of sodium transport, indicating that the sodium transport process was electrogenic. Variations in transmural p.d. showed that the sodium transport process included two components: one that varied with p.d. and one that was independent of it. These findings have been interpreted in terms of a system for sodium transport composed of three components: two rate‐limiting entry mechanisms at the apical membrane, one of which can be represented as a conductive channel for sodium diffusion and the other as a neutral process possibly a sodium‐hydrogen exchanger, and a voltage‐independent pump at the basolateral membrane analogous to the constant‐current pump models described in some other epithelia. The tissue maintained a net secretory movement of chloride in the short‐circuited condition. The process responsible for net transport of chloride could be resolved into two components: one that was sodium dependent, electrogenic, and abolished by 8 X 10(‐3) M‐acetazolamide, and one that was independent of the presence of sodium, electrically silent and abolished by 5 X 10(‐4) M‐SITS (4‐acetamido‐4'‐isothiocyano‐2,2'‐disulphonic acid stilbene). Both components of the chloride transport process varied with p.d. These findings were interpreted in terms of a system of three components: two entry mechanisms at the basolateral membrane including a coupled sodium‐chloride influx process and a chloride‐bicarbonate exchanger in parallel, and a rate‐limiting conductive channel at the apical membrane. In addition, the studies on the effects of variations in transmural p.d. on chloride fluxes revealed a symmetrical voltage‐independent component, dependent on the presence of chloride in the trans compartment, and it was suggested that this component may reflect the presence of a chloride‐chloride exchange mechanism.