Quantification of thermal energy deposited in silicon by multiple femtosecond laser pulses.

We report our study of deposited thermal energy in silicon induced by multiple-pulse femtosecond laser irradiation. Using infrared thermography, we quantified through in situ direct measurement of temperature fields that a significant portion of laser power (two-thirds or more) was deposited into the silicon substrate instead of being reflected or carried away with the ablated material. This is believed to be the first reported study of direct in situ measurement of temperature fields as the result of deposited thermal energy from multiple femtosecond laser pulses. Our simulation results support the measured data.

DNA fragments in the blood plasma of cancer patients: quantitations and evidence for their origin from apoptotic and necrotic cells.

Increased levels of DNA fragments have frequently been found in the blood plasma of cancer patients. Published data suggest that only a fraction of the DNA in blood plasma is derived from cancer cells. However, it is not known how much of the circulating DNA is from cancer or from noncancer cells. By quantitative methylation-specific PCR of the promoter region of the CDKN2A tumor suppressor gene, we were able to quantify the fraction of plasma DNA derived from tumor cells. In the plasma samples of 30 unselected cancer patients, we detected quantities of tumor DNA from only 3% to as much as 93% of total circulating DNA. We investigated possible origins of nontumor DNA in the plasma and demonstrate here a contribution of T-cell DNA in a few cases only. To investigate the possibility that plasma DNA originates from apoptotic or necrotic cells, we performed studies with apoptotic (staurosporine) and necrotic (staurosporine plus oligomycin) cells in vitro and with mice after induction of apoptotic (anti-CD95) or necrotic (acetaminophen) liver injury. Increasing amounts of DNA were found to be released in the supernatants of cells and in the blood plasma samples of treated animals. A clear discrimination of apoptotic and necrotic plasma DNA was possible by gel electrophoresis. The same characteristic patterns of DNA fragments could be identified in plasma derived from different cancer patients. The data are consistent with the possibility that apoptotic and necrotic cells are a major source for plasma DNA in cancer patients.

Capillary leak syndrome associated with elevated IL-2 serum levels after allogeneic bone marrow transplantation.

The pathophysiological mechanisms involved in the development of a spontaneous systemic capillary leak syndrome (CLS) are unknown. In contrast, CLS is a well-known side effect of high-dose interleukin-2 (IL-2) therapy in solid tumors. We report on a patient who developed CLS with high serum levels of endogenous IL-2 under immunosuppressive therapy for chronic graft-versus-host disease (GvHD) after allogeneic bone marrow transplantation (BMT). Generalized edema persisted for 10 weeks. The condition resolved after antibiotic therapy of a septic shock with beta hemolyzing streptococci group A. Thus, a latent infection may alter cytokine homeostasis and may cause CLS in BMT patients.