Hypoxia increases tumor cell shedding of MHC class I chain-related molecule: role of nitric oxide.

The MHC class I chain-related (MIC) molecules play important roles in tumor immune surveillance through their interaction with the NKG2D receptor on natural killer and cytotoxic T cells. Thus, shedding of the MIC molecules from the tumor cell membrane represents a potential mechanism of escape from NKG2D-mediated immune surveillance. Tumor hypoxia is associated with a poor clinical outcome for cancer patients.

Lymphokine-activated killer cell susceptibility and adhesion molecule expression of multidrug resistant breast carcinoma.

Reports showing susceptibility of multidrug resistant (MDR) cancer cells to immune effectors, together with P-glycoprotein (P-gp) expression in immune effector subsets, including immature natural killer (NK) cells, and some activated T cells, suggest P-gp or some changes associated with it, have implications in immune-mediated mechanisms. A series of experiments were done to determine the nature of alterations associated with susceptibility to immune effector cells of MDR tumor cells. A cell line isolated from the malignant pleural effusion of a breast cancer patient was transfected with human and murine MDR1 genes, and four variants with different levels of MDR were obtained.

Oxygen as a regulator of cellular phenotypes in pregnancy and cancer.

Cellular phenotype is determined by genetic and microenvironmental factors. There is evidence that tissue oxygenation status is one of the microenvironmental factors regulating cellular behaviour. Both normal and pathological processes such as blastocyst implantation in the uterus, placentation, and rapidly growing tumours occur under conditions characterized by relatively low oxygen levels.

[Effect of single alpha-particle on cells].

The mechanisms of biological effect of charged particles in space was studied through the inactivation effect of very low-density charged particles on very low-density cells at different impact parameters. A small type of microbeam facility with alpha-radioactive source and CN track detector were used. A diploid wild type Saccharomyces cerevisiae served as experimental eukaryotic cell.

Problems identified by tutors in a hybrid problem-based learning curriculum.

Problem-based learning (PBL) tutors (n = 27) were interviewed to identify problems they encountered in facilitating a hybrid PBL-lecture curriculum. Analysis of responses yielded six problems for students: "mini-lecturing," dysfunctional group dynamics, completing cases too quickly, superficial research, frustration with tutors who lack content expertise, and lack of support for PBL. These may arise because students lack problem-solving and interpersonal skills needed to benefit from PBL.