New biomedical devices with selective peptide recognition properties. Part 1: Characterization and cytotoxicity of molecularly imprinted polymers.

Molecular imprinting is a technique for the synthesis of polymers capable to bind target molecules selectively. The imprinting of large proteins, such as cell adhesion proteins or cell receptors, opens the way to important and innovative biomedical applications. However, such molecules can incur into important conformational changes during the preparation of the imprinted polymer impairing the specificity of the recognition cavities. The "epitope approach" can overcome this limit by adopting, as template, a short peptide sequence representative of an accessible fragment of a larger protein. The resulting imprinted polymer can recognize both the template and the whole molecule thanks to the specific cavities for the epitope. In this work two molecularly imprinted polymer formulations (a macroporous monolith and nanospheres) were obtained using the protected peptide Z-Thr-Ala-Ala-OMe, as template, and Z-Thr-Ile-Leu-OMe, as analogue for the selectivity evaluation, methacrylic acid, as functional monomer, and trimethylolpropane trimethacrylate and pentaerythritol triacrylate (PETRA), as cross-linkers. Polymers were synthesized by precipitation polymerization and characterized by standard techniques. Polymerization and rebinding solutions were analyzed by high performance liquid chromatography. The highly cross-linked polymers retained about 70% of the total template amount, against (20% for the less cross-linked ones). The extracted template amount and the rebinding capacity decreased with the cross-linking degree, while the selectivity showed the opposite behaviour. The PETRA cross-linked polymers showed the best recognition (MIP 2-, alpha=1.71) and selectivity (MIP 2+, alpha'=5.58) capabilities. The cytotoxicity tests showed normal adhesion and proliferation of fibroblasts cultured in the medium that was put in contact with the imprinted polymers.

[Left intraventricular thrombosis causing an embolism to the right leg during an acute myocardial infarct. A report of a case monitored echocardiographically with diagnostic and therapeutic comments]. / Trombosi endoventricolare sinistra embolizzante alla gamba destra in corso di infarto miocardico acuto. Descrizione di un caso monitorizzato ecocardiograficamente con considerazioni diagnostiche e terapeutiche.

Report of a case of a 54-year-old man who, during acute anterior myocardial infarction developed an apical thrombus and an embolism of the right leg. The serial echocardiographic study demonstrates how the original shape of the thrombus acutely changed at the same time of the embolic episode and how the new morphology of the thrombotic mass after embolism and thrombolytic plus anticoagulant therapy (performed for the acute ischaemic episode of the leg) was widely different from the initial one. The role of cross-sectional echocardiography is emphasized for the diagnostic value in case of intraventricular thrombi and for possible utilization also for therapeutic guidance.