Evaluation of four elastomeric interocclusal recording materials

Background: The fabrication of dental prosthesis requires the transfer of interocclusal records from patient's mouth to semiadjustable articulators using different kinds of recording media. Any inaccuracy in these interocclusal records leads to occlusal errors in the final prosthesis. This study was conducted to evaluate the dimensional changes occurring in the interocclusal recording material over a given period of time and the material's resistance to compression during the cast mounting on the articulator.     

Integrin α6 expression in human prostate carcinoma cells is associated with a migratory and invasive phenotypein vitro andin vivo

Cell adhesion and migration are important features in tumor invasion, being mediated in part by integrins (extracellular matrix receptors). Integrins are significantly decreased in human prostate cancer. An exception is 6 integrin (laminin receptor) which persists during prostate tumor progression. We have selected high (DU-H) and low (DU-L) expressors of 6 integrin from a human prostate tumor cell line, DU145, to assess experimentally the importance of 6 integrin in tumor invasion. DU-H cells exhibited a four-fold increased expression of 6 integrin on the surface compared to DU-L cells. Both cell types contained similar amounts of 3 and 5 integrin. The DU-H cells contained 6 subunits complexed with both the 1 and 4 subunits whereas DU-L cells contained 6 complexed only with 4. DU-H cells were three times more mobile on laminin as compared to DU-L, but adhered similarly on laminin. Adhesion and migration were inhibited with anti-6 antibody. Each subline was injected intraperitoneally into SCID mice to test its invasive potential. Results showed greater invasion of DU-H compared to DU-L cells, with increased expression of a6 integrin on the tumor at the areas of invasion. These data suggest that 6 integrin expression is advantageous for prostate tumor cell invasion.     

Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos

In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture environment differs from in-vivo conditions in that the oxygen concentration is higher, and in such conditions the mouse embryos show a higher concentration of reactive oxygen species (ROS) in simple culture media. ROS are believed to cause damage to cell membranes and DNA fragmentation in somatic cells. This study was conducted to ascertain the level of H2O2 concentration within embryos and the morphological features of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31 fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was obtained from the IVF-embryo transfer programme. The relative intensity of H2O2 concentrations within embryos was measured using 2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence imaging and DNA fragmentation was observed with transmission electron microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/- SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed only in fragmented embryos, and was absent in non-fragmented embryos. Electron microscopic findings confirmed apoptotic bodies and cytoplasmic condensation in the fragmented blastomeres. We conclude that there is a direct relationship between increased H2O2 concentration and apoptosis, and that further studies should be undertaken to confirm these findings.      

A human xenograft model for testing early events of epithelial neoplastic invasion

We report on a model of human prostate tumor cell invasion using the SCID (severe combined immunodeficient) mouse diaphragm. Tumor cells were injected into SCID mice intraperitoneally and the diaphragms harvested three to five weeks later. Electron microscopy showed tumor cell penetration of the mesothelial cell layer and adhesion to the underlying basement membrane on the inferior surface of the mouse diaphragm, where colonies developed. Immunohistochemistry showed invasion by tumor cells through the basement membrane into the muscle of the diaphragm, presence of human tumor cells among the muscle cells and the presence of selected proteins on the invasion front of the tumor cells. Digital image analysis enabled quantitative comparison of events in the metastatic cascade by variants of the tumor cell line and evaluation of the effectiveness of a putative tumor inhibitor. Results suggest that the SCID mouse diaphragm model is a convenient, effective, easily oriented and reproducible in vivo model of the early events associated with human prostate tumor cell invasion.     

CLINICO-EPIDEMIOLOGICAL ALGORITHM FOR PREDICTING SYSTEMIC ARTERIAL HYPERTENSION AT HIGH ALTITUDE THROUGH MATHEMATICAL MODELLING

A population based hybrid design combining element of cohort and cross-sectional approach was used to develop a simple clinical algorithm to predict individual probability of developing hypertension (systolic BP > 140 mm Hg and/or diastolic BP > 90 mmHg). 3615 soldiers initially normotensive at the time of induction into high altitude, were studied by systematic random sampling. Multiple logistic regression analysis showed a high significant association between hypertension and age, body mass index (BMI), tobacco smoking and alcohol consumption. Using the constant/coefficient values obtained from the logistic model and the receiver operating characteristics (ROC) curve analysis, the following predictive rule was developed – To the age in years, add (BMIx 3.86); also add 5.53 if he is a smoker; and add 19.81 if he consumes alcohol. If the total exceeds 142, the individual is at high risk of developing hypertension. This algorithm carries a sensitivity of 68.2% and specificity of 78.5%.KEY WORDS: Hypertension, High altitude     

PREVALENCE OF MICROALBUMINURIA IN NON-INSULIN-DEPENDENT DIABETES MELLITUS

The prevalence of microalbuminuria was assessed in 50 patients of non-insulin dependent diabetes mellitus. The mean age of patients was 52.1 ± 11.6 years and the duration of diabetes was 8.3 ± 6.8 years. Twenty (40%) patients had microalbuminuria. Microalbuminuria was more common in patients with a longer duration of diabetes (more than 5 years), a poor glycaemic control, and higher systolic blood pressure.KEY WORDS: Microalbuminuria, Diabetes mellitus, Diabetic nephropathy, Chronic renal failure