Human whole-blood granulocyte aggregation invitro

1. Aggregation assays are a commonly used technique for the study of granulocyte activation. These studies are usually performed using a pure cell suspension in buffer. This necessitates a separation procedure which is time-consuming and may modify the function of the cells. Interaction between different cell types is precluded. 2. To avoid these disadvantages a method was developed which quantifies granulocyte aggregation in whole blood. Samples drawn from an incubated vessel before and after the addition of a chemotactic stimulus were fixed with formaldehyde to prevent disaggregation. Erythrocytes were then removed by chemical lysis and using an electronic cell-sizing device the number of single cells and aggregates could then be easily measured. 3. Results from a group of volunteers showed a rapid and reversible response to a chemotactic tripeptide, with a fall in single granulocyte count and the appearance of doublets and triplets. Lymphocytes were unaffected. Intra-assay reproducibility was better than ± 5%. 4. Using this assay, a significant elevation in aggregability was observed in blood from patients after acute myocardial infarction. 5. This novel technique, by avoiding the separation step, is faster, simpler and more physiological than previous methods, and as such is useful for both assays of drug action in vitro and the study of cell activation in disease states.</jats:p

Low level laser therapy and tissue engineered skin substitutes: effect on the proliferation rate of 3T3 mouse fibroblast cells

With the rapid development of tissue engineering and gene therapy, collagen-based biomaterials are frequently used as cell transplant devices; an example is tissue-engineered skin substitutes. In this study of low level laser therapy (LLLT) we determined the influence of the irradiation and treatment parameters on the proliferation rate of 3T3 mouse fibroblast cells cultured on collagen-glycosaminoglycan (GAG) lattices and Petri dishes for up to 4 and 7 days respectively. Helium-Neon (He-Ne) laser at 1 - 4 J/cm2 was used to irradiate the cells. Using 5-carboxyfluorescein diacetate (CFDA) fluorescence, studies on the proliferation rate of irradiated cells before and after cell attachment, and on different treatment days were conducted. The viability of cells on collagen-GAG lattices were assessed using the MTT assay. It was found that in terms of cell proliferation, the cells irradiated at different fluences and treatment modes (at 3 J/cm2) showed no statistically significant difference from the control cells. Control cells on collagen-GAG lattices were found to be more viable than the irradiated cells. It was concluded that with existing experimental conditions, LLLT was found to have no statistically significant effect on the post-cell attachment proliferation and viability of 3T3 mouse fibroblast cells

An assessment of red cell deformability using a simple filtration method.

We assessed the simple method of measuring red cell deformability described by Reid et al. The technique was found to be reproducible. The validity of the method as a measure of red cell deformation was confirmed by (a) marked reduction of the deformability index after fixation of red cells with glutaraldehyde, and (b) an inverse correlation of deformability index with high-shear blood viscosity (r = 0.4; P < 0.001). There was no correlation of deformability index with low-shear blood viscosity, plasma viscosity, fibrinogen, or the white cell count. In normal subjects, deformability index was similar in males and females, and in smokers and non-smokers. Patients with acute myocardial infarction, or intermittent claudication, had reduced deformability compared to controls (P < 0.01)