Different patterns of angiogenesis in sarcomas and carcinomas.

Solid tumors depend on angiogenesis for growth and metastasis. It has been shown that blood vessel density, as determined by counting the number of capillaries in clustered bursts, is a significant prognostic factor in carcinomas. It is unclear, however, whether vessel density is a prognostic factor in sarcomas. In this study, we examined angiogenesis in sarcomas of various grades and compared their vascular patterns to those of carcinomas. Microvessels were identified by von Willebrand factor staining. The matrix of multiple sarcoma and breast carcinoma specimens were extracted and subjected to Western analysis of various angiogenic factors and inhibitors. Metalloproteinase inhibitor presence was also determined by in situ hybridization. In breast carcinomas, capillaries were clustered in bursts within the stroma of the tumor, whereas the sarcoma capillaries were homogeneously distributed in the tumor stroma. Random blood vessel density per high power field in sarcomas did not correlate with patient prognosis. The matrix of sarcomas and carcinomas contained both angiogenic stimulators and inhibitors. Tissue inhibitor of metalloproteinase-1 was found predominantly in fibroblasts and myofibroblasts in the matrix of carcinoma specimens. The difference in the pattern of angiogenesis in sarcomas and carcinomas may be attributable to the presence of fibroblasts and myofibroblasts in carcinomas, resulting in the compartmentalization of bursts of angiogenic factors. The homogeneous appearance of vessel density in sarcomas observed in the present study would be the consequence of the influence of a single compartment.

Feasibility of "limited" echo imaging: characterization of incidental findings.

To evaluate the feasibility of limiting the extent of the echocardiographic examination without omitting significant incidental findings, we reviewed consecutive reports from full echo studies performed in a tertiary medical center with the following referral questions: "rule-out pericardial effusion" (n = 40) and "rule-out source of embolus" (n = 132). Specific limited echo imaging protocols were formulated without unnecessary imaging (that is, unrelated to the diagnostic question) or use of Doppler. The percentage of full echo studies with significant incidental findings was determined, categorized by patient age, and then recalculated by whether the specific limited imaging protocol could potentially detect any or all of the incidental findings. The percentage of cases with significant incidental findings was 45% and 36% in the "rule-out" pericardial effusion and source of embolus groups, respectively. This percentage was dependent on age <65 years versus > or =65 years (22% vs 42%, p < 0.005). Limited imaging protocols could identify > or =85% of cases with significant incidental findings. These data suggest that limited echo imaging may be feasible in certain patient groups and referral diagnoses.

Noninterferometric optical subtraction using reflection-electroabsorption modulators.

A noninterferometric technique for optical subtraction is demonstrated that employs a multiple-quantum-well reflection-electroabsorption modulator and provides lower insertion loss, larger contrast ratio, and linearity over a larger dynamic range than similar techniques previously reported.

Potentiation of azidothymidine cytotoxicity in cisplatin-resistant human ovarian carcinoma cells.

The combination of cisplatin and AZT was synergistic in a subline (A2780DDP) of human ovarian carcinoma cells resistant to cisplatin, in contrast to the parental carcinoma cell line, A2780S. A2780DDP cells have elevated levels of enzymes necessary for DNA synthesis and repair. If A2780DDP cells respond to cisplatin with an increase in thymidine kinase activity, then AZT may chain terminate newly synthesized DNA. To test this hypothesis, a dual label [( 14C]-thymidine/[3H]-AZT) experiment was designed. A2780 cells were first incubated with [14C]-thymidine to label DNA and measure DNA degradation in response to cisplatin. These [14C]-thymidine labeled A2780 cells were then incubated for short intervals with [3H]-AZT to measure chain termination after cisplatin addition. A2780S cells responded to cisplatin with a modest increase in thymidine turnover and an increase in AZT incorporation. In contrast, A2780DDP cells initially responded to cisplatin treatment with a significant increase in thymidine turnover and a corresponding increase in [3H]-AZT incorporation. This was concomitantly associated with an increase in thymidine kinase mRNA within 2 hr after cisplatin treatment. Thus, the A2780DDP cells had the ability to rapidly turnover DNA, a property effectively exploited by the deoxythymidine analogue, AZT, utilizing the enhanced enzymes of the DNA synthesis and repair complex in A2780DDP cells.