[The research on applications of diagnostic software in single photon emission computed tomography]

In this paper, the structure of software system, the principles of overlay programming and the running mechanism of the programs for the Single Photon Emission Computed Tomography(SPECT) made by French SOPHA MEDICAL Corp. are analyzed in detail. On this basis, a method of extending functions of the system is introduced too. All the results of the extension in software functions for organ volume determination and of the measurements for living animals have proved the correctness and reliability of the method.

Damaging effects of anal stretching on the external anal sphincter

PURPOSE

This study was undertaken to investigate the effects of anal stretching on anal pressures and damage to the external anal sphincter.

METHODS

This study was performed on 37 guinea pigs. Animals were divided into three groups: control group, quick stretching group, and continuous overstretching group. Anal stretching was conducted by an 8-F Foley catheter balloon.

RESULTS

It was found that if the muscle was stretched from 100 to 300 percent of its original length, anal resting pressure (ARP) kept relatively steady, but anal contracting pressure (ACP) gradually increased; from 300 to 370 percent, a sharp ARP increase was developed, but ACP gradually decreased to zero; beyond 370 percent, ARP remained unchanged (plateau phase). By histologic examination, it was revealed that when the muscle was stretched at the ARP plateau phase, an ischemic zone of necrosis and an edematous zone of necrosis could be clearly identified in the muscle.

CONCLUSION

This study shows that length of the external anal sphincter definitively influences muscle strengths, and severe anal stretching will result in muscle damage. These results imply that the sphincteric muscle complex in high or intermediate anorectal anomalies may be injured during present conventional surgical approaches.

Thrombus imaging in dogs with a monoclonal antibody (SZ-51) specific for activated human platelets

To specifically detect the localization of thrombus in vivo, we prepared a monoclonal antibody (McAb) SZ-51 specific for an alpha-granule membrane protein (GMP-140) on the surface of activated human platelets. The thrombus binding rate in vitro was 80 +/- 5% for 131I-SZ-51 and 4.4 +/- 0.5% for 131I-nonimmune IgG. Owing to the crossreaction of McAb SZ-51 with the activated platelets of dogs, thrombus in the femoral artery and vein of dogs was formed and imaged with single photon emission computerized tomography (SPECT). The ratio of thrombus to blood radioactivity (T/B) was 2.1, 4.8, 14.0 and 18.0 at 1, 2, 3 and 4 hours after injection of 131I-SZ-51 (0.6 mCi, 50 micrograms) into the arterial thrombus respectively, while the T/B ratio was 1.7, 2.2, 5.3 and 8.0 for venous one. The injection of 131I-nonimmune IgG at the same doses yielded a T/B ratio of 1.2 +/- 0.3 at each time period for both arterial and venous thrombi. These findings were in good agreement with the counting of removed thrombi 24 hours after the injection of radiotracer. The ratio was 21.7 and 2.6 for the 131I-SZ-51 in the arterial and venous thrombus, respectively. However, there were only 1.48 and 1.6 for the 131I-nonimmune IgG. These results indicate the great potentiality of McAb SZ-51 in application to detection of thrombi in vivo.