Tibial and fibular shaft fractures.
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Biomedical subjects
Publications and source records attributed to A J de Klerk.
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Total hip replacement was carried out on 22 patients under general anaesthesia. Of these, 10 were pretreated with methylprednisolone (30 mg/kg); 1 of these developed the adult respiratory distress syndrome (ARDS) and had high levels of thromboxane B2 (TXB2) 5 minutes after fixation of the femoral prosthesis and at the end of the operation. The other 12 patients served as controls; 5 of them developed ARDS and had statistically significant higher TXB2 levels than the other 7 control patients who remained well. All patients who did not develop ARDS had low TXB2 levels. TXB2 and beta-thromboglobulin levels followed the same trend and there was good correlation (r=0,6806; P less than 0,01) at the end of the operation in the control group patients who developed ARDS. There was no statistical difference in 6-keto-PGF1 alpha levels between the patients who developed ARDS and those in the control group who remained well. Steroids reduce arachidonic acid metabolism by inhibiting the release of substrate for cyclo-oxygenase and lipoxygenase activity. Patients prone to ARDS thus benefit from methylprednisolone administration.
Prostacyclin (PGI2) appears to be synthesized in the lungs of man and experimental animals. It has been stated that PGI2 must be regarded as a local hormone that inhibits platelet adhesion to vessel walls only very close to the site of synthesis. The wide range of normal values given for PGI2 may be related to the sensitivity and exclusiveness of the different assay techniques used. In animals hyperventilation increases PGI2 synthesis by the lung, but in agreement with other authors we demonstrated that hyperventilation did not influence PGI2 synthesis in man. We used a radio-immunoassay technique to estimate PGI2 levels.
The management of a severed tendon within the digital sheath continues to present a formidable challenge. The major problem is one of excessive scar tissue formation. It was found experimentally in severed and partially divided tendons that the source of the blood supply, i.e. the vasculature in the tendon proper, will promote healing through the primary tissue (tenoblast) of the tendon itself, whereas the blood supply and granulation tissue from the damaged area of the flexor sheath leads to fibrous (scar) tissue formation. In this study of tendon repair special attention was paid to a suturing procedure which would have the least effect on the intrinsic blood supply to the severed ends. It was found that the basic requirement in successful tendon repair was to approximate and not to strangulate, and to minimize trauma to the flexor sheath which is the main source of scar tissue.