Rational design of small indolic squaraine dyes with large two-photon absorption cross section.

Small organic dyes with large two-photon absorption (TPA) cross sections (δ) are more desirable in many applications compared with large molecules. Herein, we proposed a facile theoretical method for the fast screening of small organic molecules as potential TPA dyes. This method is based on a theoretical analysis to the natural transition orbitals (NTOs) directly associated with the TPA transition. Experimental results on the small indolic squaraine dyes (ISD) confirmed that their TPA cross sections is strongly correlated to the delocalization degree of the NTOs of the S2 excited states. Aided by this simple and intuitive method, we have successfully designed and synthesized a small indolic squaraine dye (ISD) with a remarkable δ value above 8000 GM at 780 nm. The ISD dye also exhibits a high singlet oxygen generation quantum yield about 0.90. The rationally designed TPA dye was successfully applied in both two-photon excited fluorescence cell imaging and in vivo cerebrovascular blood fluid tracing.

Netrin-1 protects against L-Arginine-induced acute pancreatitis in mice.

Acute pancreatitis (AP) is a common inflammatory disease mediated by damage to acinar cells and subsequent pancreatic inflammation with infiltration of leukocytes. The neuronal guidance protein, netrin-1, has been shown to control leukocyte trafficking and modulate inflammatory responses in several inflammation-based diseases. The present study was aimed toward investigating the effects of netrin-1 in an in vivo model of AP in mice. AP was induced in C57BL/6 mice by administration of two intraperitoneal injections of L-Arginine (4 g/kg). Mice were treated with recombinant mouse netrin-1 at a dose of 1 µg/mouse or vehicle (0.1% BSA) intravenously through the tail vein immediately after the second injection of L-Arginine, and every 24 h thereafter. Mice were sacrificed at several time intervals from 0 to 96 h after the induction of pancreatitis. Blood and tissue samples of pancreas and lung were collected and processed to determine the severity of pancreatitis biochemically and histologically. Immunohistochemical staining demonstrated that netrin-1 was mainly expressed in the islet cells of the normal pancreas and the AP model pancreas, and the pancreatic expression of netrin-1 was down-regulated at both the mRNA and protein levels during the course of AP. Exogenous netrin-1 administration significantly reduced plasma amylase levels, myeloperoxidase activity, pro-inflammatory cytokine production, and pancreas and lung tissue damages. Furthermore, netrin-1 administration did not cause significant inhibition of nuclear factor-kappa B activation in the pancreas of L-Arginine-induced AP. In conclusion, our novel data suggest that netrin-1 is capable of improving damage of pancreas and lung, and exerting anti-inflammatory effects in mice with severe acute pancreatitis. Thus, our results indicate that netrin-1 may constitute a novel target in the management of AP.

[The change of serum vascular endothelial growth factor and matrix metalloproteinases-9 in proliferative hemangioma treated with propranolol].

OBJECTIVE: To study the level of serum vascular endothelial growth factor, matrix metalloproteinases-9 in the proliferative hemangioma before and after propranolol treatment. METHODS: The serum VEGF, MMP-9 was detected with ELISA assay before treatment and after 4 weeks and 8 weeks of propranolol treatment. The relationship between the serum VEGF, MMP-9 and the prognosis was analyzed. RESULTS: The serum VEGF (295.4 +/- 158.1) pg/ml was high before treatment, then decreased after 4 weeks and 8 weeks of treatment (255.7 +/- 130.4) pg/ml, (224.2 +/- 120.6) pg/ml. The serum VEGF was significantly lower after 8 weeks of treatment (P < 0.05). The serum MMP-9 was also decreased after treatment, showing a positive relationship with VEGF. CONCLUSIONS: Propranolol can treat the proliferative hemangioma through decreasing the serum VEGF and MMP-9.