Safety of computer-assisted surgery for cannulated hip screws.

Computer-assisted orthopaedic surgery has developed considerably during the past few years. Several manufacturers produce hardware and software for use in trauma surgery. Validation of these systems before clinical application is mandatory to be sure they work accurately and safely. The accuracy of surgical performance is highly correlated with the cut-out percentages of hip screws. In a standardized operative setting, three cannulated hip screws were inserted in each of 20 sawbones. The screws were positioned either by fluoroscopic navigation technique or by conventional operative technique depending on randomization. Our primary aim was to assess whether computer-navigated screw fixation is equally safe compared with conventional screw fixation using fluoroscopy. To determine safety, we investigated number of drilling attempts, screw position, and radiation time. Secondary to these safety parameters, we also compared the operating time between the two procedures to assess the efficiency of computer navigation. Statistical analysis showed no differences regarding accuracy of screw position. Computer-assisted surgery resulted in fewer drilling attempts and less radiation time, with a similar operation time. We believe the currently used navigation system is safe and accurate.

Congenital heart defects and maternal derangement of homocysteine metabolism.

Methionine loading tests and folate, vitamin B(6), and vitamin B(12) analyses were performed in 27 mothers of children with congenital heart defects. Median fasting plasma homocysteine concentrations were significantly higher in the study group as compared with 56 control subjects (P =.0001). Maternal hyperhomocysteinemia may be a risk factor for congenital heart defects.

Adsorption and uptake of the alkyllysophospholipid ET-18-OCH3 by HL-60 cells during induction of differentiation by dimethylsulfoxide.

The human leukemic cell line HL-60 is highly sensitive to the antineoplastic agent alkyllysophospholipid, 1-octadecyl-2-methyl-sn-glycerol-3-phosphocholine (ET-18-OCH3). We investigated the adsorption and uptake of radiolabeled ET-18-OCH3 in undifferentiated HL-60 cells and during differentiation to granulocytes induced by dimethylsulfoxide. HL-60 cells become less sensitive to the cytotoxic action of ET-18-OCH3 during differentiation. The decrease in sensitivity is correlated with a decrease in both adsorption and uptake of [3H]ET-18-OCH3 during differentiation. Binding studies revealed that the binding of ET-18-OCH3 to both undifferentiated and differentiated HL-60 cells is non-saturable which renders the existence of a specific binding place highly unlikely.