Real-time detection of NAD(P)H is particularly important for understanding physiological activities of neutrophils. We scrutinize the erformance of weak light detection systems with electron multiplying CCDs (EMCCDs) with regard to the feasibility of valid investigations by tofluorescence NAD(P)Hin single human neutrophils. The low-noise amplification facility of EMCCDs is indeed just adequate to permit detection at an irradiation level where neither quenching nor phototoxic effects occur. For demonstration, a neutrophil respiratory burst was triggered and observed in real time. Our low-intensity detection system fulfills all requirements for real-time investigations at high spatiotemporal resolution in the field of neutrophil physiology and pathology.

PMA-induced respiratory burst neutrophils were exposed to exogenous nitric oxide (NO) donor sodium nitroprusside (SNP) to study the effect of NO on calcium signaling. A sharp rise of cytosolic calcium concentration ([Ca2+]c) was triggered by 1 mM SNP with and without external calcium. We found that GF 109203X, a specific inhibitor of protein kinase C, DPI, a putative inhibitor of the respiratory burst-generating NADPH oxidase, and 2-DG, a non-metabolizable analog of glucose, completely inhibited the SNPinduced rise of [Ca2+]c in PMA-activated respiratory burst neutrophils. Meanwhile, 2-APB and TMB-8, two potent IP3 receptor inhibitors, prevented calcium increase respectively. Furthermore, N-ethylmaleimide (NEM), a specific cysteine alkylating agent, evidently abolished the [Ca2+]c elevation. In contrast, the sGC inhibitor NS2028 had little effect on the rise of [Ca2+]c. Taken together, these results indicated that exogenous NO induced the release of calcium from intracellular IP3 receptor-sensitive stores of neutrophils via S-nitrosylation in a respiratory burst-dependent manner.

Femtosecond laser ablation of silver plate placed in water is used to produce nanoparticle suspension. The method is easy to operate and the suspension is relatively stable. The optical properties and the size distribution of the suspension are studied with UV-vis absorption spectroscopy and dynamic light scattering, respectively. The shape of the nanoparticles is investigated by an atomic force microscope, which is near spherical. There are two kinds of nanoparticles, small particles with diameter about 35 nm, and large particles with diameter about 120 nm.

Normalized Mandel Parameter <Q> is introduced as a new measurement of photon statistics. Dependences of Mandel parameter and corresponding ormalized Mandel parameter<Q> on photon-counting time interval are experimentally investigated for pseudo-thermal light. We demonstrate that <Q> is more appropriate than to measure the statistical deviation from Poisson distribution, because <Q> presents clearly both the intrinsic statistical properties and measuring effects. The advantages of <Q> in charactering nonclassical emissions are also discussed.