Chemosensitization of tumors via simultaneous delivery of STAT3 inhibitor and doxorubicin through HPMA copolymer-based nanotherapeutics with pH-sensitive activation.

We synthesized three novel STAT3 inhibitors (S3iD1-S3iD3) possessing oxoheptanoic residue enabling linkage to HPMA copolymer carrier via a pH-sensitive hydrazone bond. HPMA copolymer conjugates bearing doxorubicin (Dox) and our STAT3 inhibitors were synthesized to evaluate the anticancer effect of Dox and STAT3 inhibitor co-delivery into tumors. S3iD1-3 and their copolymer-bound counterparts (P-S3iD1-P-S3iD3) showed considerable in vitro cytostatic activities in five mouse and human cancer cell lines with IC50 ~0.6-7.9 µM and 0.7-10.9 µM, respectively. S3iD2 and S3iD3 were confirmed to inhibit the STAT3 signaling pathway. The combination of HPMA copolymer-bound Dox (P-Dox) and P-S3iD3 at the dosage showing negligible toxicity demonstrated significant antitumor activity in B16F10 melanoma-bearing mice and completely cured 2 out of 15 mice. P-Dox alone had a significantly lower therapeutic activity with no completely cured mice. Thus, polymer conjugates bearing STAT3 inhibitors may be used for the chemosensitization of chemorefractory tumors.

Alkylphenol ethoxylates and alkylphenols--update information on occurrence, fate and toxicity in aquatic environment.

Alkylphenols and their precursors, alkylphenol etoxylates, are a group of manmade chemicals used mainly as surfactants in domestic and industrial applications worldwide. It has been well established that they have endocrine disruption activity, hepatotoxic, genotoxic and other negative effects on animal and human health. In spite of the effort to reduce their use, they persist in the environment not only in industrial but also in remote regions, and were detected in the variety of natural matrices including air, water, soil as well as food products, and human blood and urine worldwide. This article summarizes their occurrence, fate in natural conditions, and toxicity including mode of action. A subject of our concern was the aquatic environment as the most important reservoir and target of their deleterious impact.

[Colorectal screening program--participation of general gynecologists]. / Screening kolorektálního karcinomu v ordinaci praktického gynekologa--který test je ten pravý?

AIM: Colorectal screening program in the Czech republic in 2011 offers faecal occult blood test (FOBT) yearly in the age of 50-54. Patient over 55 years of age chooses either a FOBT once in 2 years or primary screening colonoscopy once in 10 years without using FOBT. There are different types of FOBT in our screening program: quaiac tests, immunochemical tests unquantitative and quantitative tests. The role of general practitioners was enhanced by participation of the gynecologists in the colorectal cancer screening program due to low compliance of population. Alternative ways of distribution of FOBT to the patients are being considered as well. CONCLUSION: Participation of general gynecologists in the Czech colorectal cancer screening program is connected with a great expectation. We would like to achieve such compliance in colorectal cancer screening as there is in the screening of gynecological tumors. Using a right method of screening could play an important role in this process.

Microdomain structure in polylactide-block-poly(ethylene oxide) copolymer films.

Structured surface is an important property of polymer biomaterials for tissue engineering, for its capacity to expose domains with different surface energy and functional groups. For this purpose, amphiphilic A-B-A block copolymers with polylactide (PLA) as A blocks and poly(ethylene oxide) (PEO 3, Mn = 3090; PEO6, Mn = 6110) as B block were synthesized by ring-opening polymerization of either L-lactide (L-LA) or DL-lactide (DL-LA), using poly(ethylene glycol)s as macroinitiators and tin(II) octanoate (Sn(Oct)2) as a catalyst. Differential scanning calorimetry (DSC) and electron microscopy were used to study the phase separation of the hydrophobic (PLA) and hydrophilic (PEO) segments in films made of the copolymers and their blends with high-molecular-weight PLA homopolymers. Hydrophilic (PEO) and hydrophobic (PLA) domains were formed at the polymer film surface due to the separation of phases. The phase separation was affected by the copolymer composition and the stereoregularity of PLA blocks in the copolymers.