Synthesis and cytotoxicity evaluation of some new 6-nitro derivatives of thiazole-containing 4-(3H)-quinazolinone.

Quinazolinones are a group of fused heterocyclic compounds which have valuable biological properties including cytotoxic, antibacterial and antifungal activities. Thiazole group-containing compounds have been also reported to have a wide range of biological activities such as antitumor, anti-inflammatory, analgesic and antibacterial effects. Due to valuable cytotoxic effects of both thiazole groups and quinazoline derivatives, in this study a series of quinazolinone-thiazole hybrids were synthesized and evaluated for their cytotoxic effects on three cell lines including MCF-7, HT-29, and PC-3. Among tested compounds (quinazolinones and three intermediates), k5 and k6 showed highest cytotoxic activities against PC3 cell line. K6 and C were most active compounds against MCF7 and K6 showed best cytotoxicity on HT-29 cell line.

Viscoelastic modeling of the contact interaction between a tactile sensor and an atrial tissue.

Modeling and parameter identification of soft tissue are essential in establishing an accurate contact model for tool-tissue interaction, which can be used in the development of high-fidelity surgical instruments. This paper discusses the interaction between a tissue and a tactile sensor in minimally invasive surgery, the focus being a novel technique for robotic-assisted mitral valve repair, in which tactile sensors are used to distinguish between different kinds of tissue by their relative softness. A discrete viscoelastic model is selected to represent the tissue behavior. To populate the model of the tissue with actual data, a set of tissue-testing experiments is designed and implemented on the atrial tissue of a swine heart by analyzing its dynamic response. By means of a genetic algorithm, data of the complex compliance are extracted and used to find the coefficients of the model. Further, a viscoelastic contact model is developed to model the interaction between the tissue and the tactile sensor with annular shape. Finally, the relation among the indentation displacement, the ratio of the radii, and the applied force is established parametrically.

A piezoresistive tactile sensor for tissue characterization during catheter-based cardiac surgery.

BACKGROUND: Currently, most of mitral valve annuloplasty surgeries are performed by using open heart surgery. However, if such operation would be performed by using minimally invasive surgery via catheter-based techniques (CBT), it offers various advantages for both surgeons and patients. METHODS: Two piezoresistive force sensors are used in the structure of the tactile sensor, which can easily be miniaturized and integrated into surgical catheters. The tactile sensor was fabricated and tested to characterize different elastomers, as the phantom of cardiac tissues. Based on a developed finite element analysis (FEA) of the elastomers, the interaction between the sensor and those materials were modelled to validate the output of the sensor. RESULTS: The results of the mechanical and psychophysical tests confirm the capability of the proposed sensor to measure the relative hardness/softness of different soft tissues. CONCLUSIONS: The proposed tactile sensor will help surgeons to characterize different types of cardiac tissues and would facilitate the use of CBT to perform mitral valve annuloplasty.