7.2. Speckle control procedures

The experiments were conducted in a liquid thermostat of ЗЦ-1125М type with the optical device shown in Figure 5 inside. Monolayers of cultured virus-free and herpes simplex virusinfected cells were the research targets. Two identical optical cuvettes were prepared for the study. There were two identical substrates in each cuvette, one with the cells and the other cellfree with nutrient solution. The experiments used HSV-1 infectious titre 4.5 lg TCD 50/ml (tissue cytopathic doses) in a dilution of 10-3. Speckle dynamics films of frequency 25 Hz lasting 20–40 s were recorded in the first experiments for 18–20 h at half-hour intervals. Cells of L41 line were the research target. Typical joint dependences ηðtÞ for the nutrient solution and virus-free and virus-infected cells are shown in Figure 20.

Figure 20. Typical joint dependences ηðtÞ for the nutrient solution (1), virus-free cells (2), and virus-infected cells (3).

Analysis of dependences of ηðtÞ as well as σuðtÞ for virus-free and virus-infected cells shows that they have features agreeing with some phases of virus development in cultured cells, but they are reproduced in about 50% of the cases. The result obtained was probably related to two considerations. First, while dependences ηðtÞ were being recorded, the initial frame, starting from the second film, did not correspond to the experiment start. Second, the optical wave path variation could have been caused by several factors with relaxation times of the same order. Appearance and disappearance of these factors could have occurred in an unpredictable mode. To eliminate the detected flaw, we altered the experimental technique. In the new technique, the program for real-time recording of dependences <sup>~</sup>Iðt<sup>Þ</sup> and <sup>η</sup>ðt<sup>Þ</sup> was started 1 h after the administration of the virus. Values ~I were determined in preselected pixels, and value η was obtained by a segment of 10 × 10-pixel size in the neighborhood of the selected pixel. In 18–20 h, the program was switched off. The frame exposure time was taken as a value exceeding the radiation intensity correlation time found by the graphs in Figure 20 and equalled 9 s.
