Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance

Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy.     

Molecular and mechanical property changes during aging of bone cement in vitro and in vivo

The changes in mechanical properties and free radical concentration of curing Simplex P Radiopaque Bone Cement in vivo and in vitro conditions were studied. Samples were prepared so that each in vivo sample that cured and aged in the canine femoral intramedullary cavities had an in vitro counterpart that was cured and aged in a constant-temperature saline bath at 37 degrees C. An electron paramagnetic resonance (EPR) spectrometer was used to measure the growth and decay (curing) of polymerization radicals. The results of EPR measurements showed that the curing (disappearance of free radicals) of in vivo samples takes a much longer time (more than 4 weeks) than in vitro curing (less than 2 weeks). The mechanical tests indicate that, whether aged in vivo or in vitro, the strength increased rapidly for the first 1-2 weeks and then slight increases were seen for up to 6 months.     

Retained intrahepatic stones: treatment with piezoelectric lithotripsy combined with stone extraction

Extracorporeal shock wave lithotripsy (ESWL) was performed in 11 patients with oriental cholangiohepatitis and intrahepatic stones associated with segmented strictures of intrahepatic ducts. All patients had previously undergone biliary surgery and basket extraction via a T-tube tract at the time of lithotripsy. The indication for ESWL was failure of, or anticipated difficulty with, basket extraction of the stones via a T-tube tract. A piezoelectric lithotriptor was used in all procedures. The average total number of shock waves administered was 29,756 (range, 10,000-61,395). The average number of treatment sessions was 3.1 (range, 1-6); the number of shock waves used in a single session ranged from 10,000 to 15,000 with a frequency of five shots per second and 30%-50% power. In six patients, the stones were successfully fragmented and completely removed; in three of the others of the stones were fragmented and removed. The overall success rate, including complete (54%) and incomplete (27%) success, was 82%. Difficulty in targeting stones, and severe strictures and deformities of intrahepatic ducts, were the factors responsible for failure. No significant complications were observed.     

Poly(L-lysine)-g-poly(D,L-lactic-co-glycolic acid) micelles for low cytotoxic biodegradable gene delivery carriers.

Poly(lactic-co-glycolic acid) (PLGA)-grafted poly(L-lysine) (PLL) (PLL-g-PLGA) was synthesized to demonstrate its micelle-forming property in an aqueous solution. The micelles were used as a gene delivery carrier. The hydrodynamic diameter of PLL-g-PLGA micelles in an aqueous solution was ca. 149 nm with a narrow size distribution. Critical micelle concentration (cmc) was 9.6 mg/l. The PLL-g-PLGA micelles could be used to produce compact nanoparticulate complexes with plasmid DNA, which could efficiently protect the complexed DNA from enzymatic degradation by DNase I. The micelle/DNA complexes had highly compacted structure sized between 200-300 nm with a positive surface charge value. The PLL-g-PLGA micelles exhibited much higher transfection efficiency with lower cytotoxicity than PLL. Here, we demonstrated that biodegradable and cationic PLL-g-PLGA micelles could be used as an effective DNA condensation carrier for gene delivery system.     

Ceftriaxone-associated gallbladder sludge. Identification of calcium-ceftriaxone salt as a major component of gallbladder precipitate

Ceftriaxone, a third-generation cephalosporin, is partially excreted into bile. With its clinical use, the formation of gallbladder sludge detected by ultrasonography has been reported. Four surgical specimens were examined and no gallstones were found. Instead, fine precipitates of 20-250 microns were present. Microscopically, there was a small number of cholesterol monohydrate crystals and bilirubin granules among an abundant amount of granular-crystalline material that was not morphologically cholesterol monohydrate crystals. The chemical composition of the precipitates (n = 4) was determined. There was a small amount of cholesterol (1.7% +/- 0.8%) and bilirubin (13.9% +/- 0.74%). The major component of the precipitate was a residue. On further analysis using thin-layer chromatography, high-performance liquid chromatography, and electron microprobe analysis, the residue was identified as a calcium salt of ceftriaxone. The residue also had identical crystal morphology and chromatographic elution profile as authentic calcium-ceftriaxone standards. It is concluded that ceftriaxone, after excretion and being concentrated in the gallbladder bile, can form a precipitate. The major constituent has been identified as a ceftriaxone-calcium salt.     

Doxorubicin-conjugated biodegradable polymeric micelles having acid-cleavable linkages.

Doxorubicin was chemically conjugated to the terminal end of a di-block copolymer composed of poly(L-lactic acid) (PLLA) and methoxy-poly(ethylene glycol) (mPEG) via two acid-cleavable linkages. A hydrazone bond and a cis-acotinyl bond were formed between doxorubicin and the terminal group of PLLA segment in the block copolymer. Doxorubicin-conjugated PLLA-mPEG di-block copolymers self-assembled to form micelles in aqueous solution. The doxorubicin-conjugated micelles were about 89.1 nm in diameter and their critical micelle concentration was 1.3 microg/ml. These values were comparable with those of unconjugated micelles. In an acidic condition, the conjugated doxorubicin in the hydrazone linkage was readily cleaved, releasing doxorubicin in an intact structure. Doxorubicin-conjugated PLLA-mPEG micelles were more potent in cell cytotoxicity than free doxorubicin, suggesting that they were more easily taken up within cells with concomitant rapid release of cleaved doxorubicin into the cytoplasm from acidic endosomes.     

Immunoscintigraphy in the detection of tuberculosis with radiolabelled antibody fragment against Mycobacterium bovis bacillus Calmette-Guérin: a preliminary study in a rabbit model.

Immunoscintigraphy with radiolabelled monoclonal antibodies is widely used to detect solid tumours, but only a few trials have been carried out concerning the specific in vivo localization of an inflammatory process. The purpose of this study was to investigate the detectability of tuberculous foci utilizing this method with radiolabelled bacillus Calmette-Guérin (BCG)-specific F(ab')2 in rabbits. All of the tuberculous lesions (n = 8) were clearly visualized on serial scintigraphy for up to 48 h after injection of the antibody. Immunohistochemical and Ziel-Neelson staining of the tuberculous lesions confirmed the presence of the tuberculous antigens and bacilli. It failed to demonstrate any sustained retention of the BCG-specific antibody fragment in the control group with syphilitic orchitis (n = 2). Therefore, the specific in vivo localization of tuberculosis is feasible by immunoscintigraphy.     

Partial mastectomy with axillary lymph node dissection and radiotherapy as a new treatment modality of breast cancer (I).

This is the first preliminary report among two consecutive papers. Partial mastectomy(PM), axillary lymph node dissection(AD) and radiotherapy (RT) were performed on seventeen operable breast cancer patients who had been admitted from April 1991 to March 1992 to the department of surgery, Yongdong Severance Hospital for improved cosmetic appearance and better survival rate. Of seventeen patients, 47% were T1 lesion and 76% were stage I and II. Extensive intraductal component(EIC) within or around the tumor was also analyzed. Twenty nine per cent of the patients were EIC positive. The mean number of axillary lymph nodes was 21.5 after PM with AD and 20.5 after mastectomy. For radiotherapy, 4,500 rad was delivered to the breast parenchyma and 1,600 rad of boost to the primary tumor site using the electron beam method after surgery. All patients have since been living well without any local recurrence and were satisfied with breast preservation for the one-year follow-up period. We concluded that the PM, AD and RT can be another surgical treatment modality of breast cancer. A longer follow-up data will be followed on the second paper.