Ultrasonic cleaning devices are in widespread use for washing various instruments contaminated with blood or other body fluids. Tap water commonly employed as a medium in washing by sonication contains, at ordinary temperature, oxygen and nitrogen gasses at approximate concentrations of 8 and 14g/m^3, respectively. These dissolved gasses are known to cause ultrasound attenuation and scattering. This study was conducted to compare ultrasonic cleaning efficiency with tap water versus deaerated water, with the results demonstrating an improved effect with the latter sonication medium. Higher sound pressure levels and lesser ultrasound damping to the water surface were observed in deaerated water, compared with tap water. In addition, a cleaning effect with the use of deaerated water was evident even for the nut regions of scissors and hemostatic forceps which have been generally thought to be difficult to thoroughly clean in tap water medium. The present data indicate potential usefulness of deaerated water as a noticeably effective means for devising a more efficient ultrasonic cleaning system, despite the difficulty in handling of this medium into which a gradual dissolution of atmospheric gasses takes place on standing.

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In order to make chronic rabbit model to study transmyocardial laser revascularization(TMLR), we report intubation-free-rabbit-model with direct surgical procedure to the heart. All the surgical procedure was performed by sterilized fashion and no antibiotics was used. Anesthesia was done by intramuscle injection with 55mg/kg ketamine and 5mg/kg xylazine(KX1)in one group and 35mg/kg ketamine and 5mg/kg xylazine(KX2)in another group. Median sternotomy was used keeping intact of visceral pleura of both lung. Voluntary respiration was kept during surgery if visceral pleura of both lung is not injured. There were no wound infection. The mortality was 71%(5/7)in KX1-group and 24%(4/17)in KX2-group(p=0.0606 : Fisher's exact probability test). Among KX2-group, we performed arterial blood gas measurement. Arterial oxygen tension(PaO_2)decreased to 40mmHg from 90mmHg, during arterial carbondioxyde tension(PaCO_2)remains around 50mmHg under the room air. Inhalation of 200ml/min oxygen improved this abnormal decrease of PaO_2. PaO_2 has kept over 100mmHg and PaCO_2 remains the same level. The anesthesia we used and inhalation of oxygen made stable condition within 60minutes procedure. The rabbit model will be worthy for further investigation of TMLR.

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As the technology for leukoreduction from blood products is advanced, sensitive and reliable methods to count extremely low number of leukocytes are expected to be developed. we evaluated IMAGN 2000(IMAGN)for the measurement of residual leukocytes in leukoreduced blood products. IMAGN is an automated volumetric capillary cytometer utilizing dyelabeled antibodies and He-Ne laser. The performance of IMAGN was tested with samples adjusted to 0.1-100/μL leukocytes from platelet concentrates(PC)as well as PC samples derived from apheresis and compared with those of Nageotte hemocytometry and flow cytometry. The reproducibility, linearity and sensitivity of the IMAGN was comparable with the two other methods at 0.1-100/μL of leukocyte concentration. The correlation coefficient(r^2)between expected and observed number of leukocytes was 0.997, 0.993 and 1.000, respectively for IMAGN, Nageotte and flowcytemeter. The coefficient of variation with IMAGN was 38.6%, 26.6% and 12.5% at the concentration of 0.1, 1 and 10/μL of leukocytes, respectively. Clear linear relationships of the leukocyte counts were observed between IMAGN and the two other methods with apheresis sample. In addition, IMAGN is advantageous over the two other methods with respect to sample preparation, measuring time and easy operation. Since 3-10/μL of residual leukocytes or less are required as final concentration after leukoreduction and IMAGN showed good performance at 0.1-10/μL of leukocyte concentration, IMAGN is sensitive and reliable enough for the measurement of residual leukocytes in leukoreduced PC in routine work.

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