Electron micrographs indicate, in harmony with previous findings, that the pneumococcal capsule is a gel of low density outside of and closely applied to the bacterial cell wall. Interaction with homologous immune rabbit serum greatly increases the thickness and density of this capsular gel; the increase in thickness of the specifically swollen pneumococcal capsule may exceed by 25-fold the thickness of the surface deposit caused by rabbit immune serum on the cell walls and flagella of homologous non-capsulated bacteria.
Conclusions drawn from these and earlier data are that homologous immune serum permeates the pneumococcal capsular gel; the specific antibody combines with the capsular polysaccharide; non-specific serum components are secondarily adsorbed to or combined with the specific antigen-antibody complex. The relatively low antibacterial titers characteristic of pneumococcal antisera can be explained in part by the permeation of the capsule by antiserum, in part by the high combining capacity of pneumococcal carbohydrate for antibody (17).
Ketamine-anesthetized female Sprague-Dawley rats were exposed individually to far-field 2.8 GHz continuous wave (CW) and pulsed (2 microseconds, 500 pps) radio-frequency radiation (RFR) at average power densities of 30, 45, and 60 mW/cm2 [specific absorption rates (SAR) of 8.4, 12.6, and 16.8 W/kg, respectively] and to pulsed RFR at 75 mW/cm2 (SAR = 21 W/kg). Intermittent exposures were conducted to repeatedly increase colonic temperature from 38.5 to 39.5 degrees C. Colonic, tympanic, and subcutaneous temperatures, electrocardiogram, respiratory rate, and arterial blood pressure were continuously monitored and recorded. The time required to effect a 1 degree C colonic temperature increase varied inversely with the average power density used during exposure; however, the rate of cooling was independent of the heating rate. During pulsed irradiation, heart rate increased significantly at average power densities above 30 mW/cm2; heart rate increase during CW exposure was not significant. Heart rate returned to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. Pulsed RFR exposure caused a significantly greater increase in subcutaneous and tympanic temperatures than did CW exposure; however, no significant difference was noted between the effects of CW or pulsed RFR upon the rats' colonic temperature responses (heating and cooling time), heart rate, blood pressure, and respiratory rate.
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