Liver mitochondria were exposed in vitro at 30 degrees C to microwave radiation (2.45 GHz) during the following states of respiration: resting, state 1; substrate dependent, state 2; ADP stimulated, state 3; and ADP depleted, state 4. At 10 or 100 mW/g, with succinate as substrate, no effect of exposure was observed on states 1-4 or the respiratory control index (state 3/state 4) of either tightly or loosely coupled mitochondria. When glutamate was used as substrate, no effects were observed at 10 mW/g. However, in the loosely coupled mitochondria the 100 mW/g exposure produced an increase in states 2 and 4 and a decrease in the respiratory control index. The results suggest that the function of loosely coupled mitochondria can be affected at high power levels of microwave radiation.

The chronotropic and inotropic effects of 2.45-GHz continuous wave (CW) microwave radiation were investigated in the isolated spontaneously beating rat atria. Isolated atria were placed in specially designed tubes inserted into a waveguide exposure system. The atria were then irradiated for a period of 30 min, followed by a 30-min recovery period. The control atria were prepared simultaneously and sham exposed. Experiments were conducted at two temperatures, 22 and 37 degrees C, and two specific absorption rates, 2 mW/g and 10 mW/g. At both temperatures the rate of atrial contraction was not altered by a 30-min exposure at either 2 or 10 mW/g. The average rate (beats per min) was approximately 100 for both the control and exposed atria at 22 degrees C and 215 beats per min for both the control and exposed atria at 37 degrees C. In addition, no inotropic effects on the spontaneously beating atria were noted at any exposure level. These data suggest that 2.45-GHz CW microwave radiation at these intensities has no overt effect on these variables in isolated rat atria.

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seem, therefore, that this technique would be detrimental to patients. However, when undertaken under controlled conditions for short periods of time (usually 2-3 h) and followed by careful resuscitation, it has produced, in our unit, excellent results in terms of minimal liver dysfunction, blood transfusion requirements and mortality. Volumes of local anaesthetic for sub-Tenon's anaesthesia vary between 2 ml and 11 ml. Lower volumes produce less akinesia, whilst higher volumes increase chemosis and intra-ocular pressures [1]. This randomised, blinded, sequential allocation study examined the effect of adding hyaluronidase on the minimum local anaesthetic volume (MLAV) required for a sub-Tenon's block, in patients having cataract extractions. MethodsFollowing Local Research Ethics Committee and Medicines and Healthcare products Regulatory Agency approval, 62 patients having sub-Tenon's blocks for cataract surgery were randomly assigned to two groups. The control group (n ¼ 31) received plain lidocaine 2% and the study group (n ¼ 31) received lidocaine 2% with 15 iu.mlhyaluronidase. Using parallel up-down sequential allocation, from a 4-ml starting point, the volumes in both groups changed by 1 ml according to the quality of globe akinesia, as judged by a blinded researcher using a standardised scoring system. The MLAV was calculated for both groups using Dixon and Massey formulae. Student's t-tests were used to compare the groups. ResultsThe groups were similar for age, sex and axial length. There was a difference in MLAV of 3.0 ml ( Fig. 1; control: 5.9 ml (95%CI 4.3-7.9 ml); hyaluronidase: 2.9 ml (95% CI 2.4-3.5 ml); p < 0.001). The hyaluronidase group showed less variability (p < 0.01).

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