Kinetics, cell

Figure C3.1.2. Stopped-flow apparatus with motor-driven syringes. Syringe plungers force tire reactants A and B tlirough a mixing chamber into a spectral cell. Kinetic data collection begins when tire effluent syringe plunger is pushed out to contact an activation switch, about a millisecond after tire initiation of mixing. (Adapted from Pilling M J and Seakins P W 1995 Reaction Kinetics (Oxford Oxford University Press)...

Optically active molecules show circular dichroism. Their extinction coefficients f l and are different and change as a function of wavelength. Using a suitable spectroelectrochemical cell, Af = fl -which is usually small compared to conventional extinction coefficients, can be measured. Combined with the special properties of a thin layer cell kinetic data can be extracted from CD-data [01 Liu]. (Data obtained with this method are labelled CD.)... 

Low level activation of MPS Interleukin-I Amyloidosis Hyperplastic liver foci Altered stem cell kinetics Altered drug metabolism Altered response to drugs C Biotechnics For biotechnics (and specifically monoclonal antibodies), factors affecting safety include... 

Kaushal D, Bansal MR, Bansal MP. 1996. Cell kinetics of the rat seminiferous epithelium following lead acetate treatment. Journal of Trace Elements in Experimental Medicine 9(2) 47-56. 

Hoste, H. (1989) Trichostrongylus colubriformis epithelial cell kinetics in the small intestine of infected rabbits. Experimental Parasitology 68, 99-104. 

MacDonald, T.T. and Ferguson, A. (1977) Hypersensitivity reactions in the small intestine. III. The effects of allograft rejection and of graft-versus-host disease on epithelial cell kinetics. Cell and Tissue Kinetics 10, 301-312. 

N. L. Simmons, and B. H. Hirst. Functional expression of P-glycoprotein in apical membranes of human intestinal Caco-2 cells. Kinetics of vinblastine secretion and interaction with modulators, J. Biol. Chem. 1993, 268, 14991-14997... 

The present work aimed to investigate the estrogenicity of industrial pollutants discharged into water resources by studying modifications in the cell kinetics of MCF7 breast cancer cell cultures and effects on the... 

Breuer R, Zajicek G, Christensen TG, Lucey EC, Snider GL (1990) Cell kinetics of normal adult hamster bronchial epithelium in the steady state. Am J Respir Cell Mol Biol 2(1) 51—58. 

Hurtt ME, Thomas DA, Working PK, et al. 1988a. Degeneration and regeneration of the olfactory epithelium following inhalation exposure to methyl bromide Pathology, cell kinetics, and olfactory function. Toxicol AppI Pharmacol 94 311-328. 

Membrane Transport in Organelles Metabolite levels in specific cells and subcellular compartments of plant leaves, 174, 518 isolation of plant vacuoles and measurement of transport, 174, 552 transport in fungal cells kinetic studies of transport in yeast,... 

Johnson SJ, Hines JE, Burt AD. 1992. Macrophage and perisinusoidal cell kinetics in acute liver injury. J Pathol 166 351-358. 

In the design and operation of various bioreactors, a practical knowledge of physical transfer processes - that is, mass and heat transfer, as described in the relevant previous chapters - are often also required in addition to knowledge of the kinetics of biochemical reactions and of cell kinetics. Some basic concepts on the effects of diffusion inside the particles of catalysts, or of immobilized enzymes or cells, is provided in the following section. 

Immunohistochemical Detection of Bromodeoxyuridine-Labeled Nuclei for In Vivo Cell Kinetic Studies... 

Wynford-Thomas, D. and Williams, E. D. (1986) Use of bromodeoxyuridine for cell kinetic studies in intact animals. Cell Tissue Kinetics 19,179—182. 

Cell Kinetic Studies Using a Monoclonal Antibody to Bromodeoxyuridine... 

Cell kinetics is defined as the measurement of time parameters m biological systems. Traditionally, this has involved the use of radioactive precursors of DNA, such as tritiated thymidine (3HTdR), and autoradiography to detect their incorporation into DNA. This technique has provided detailed knowledge of cell kinetics in both in vitro and in vivo experimental systems. The technique, however, is time consuming and arduous and is not readily applicable to human tumor research because of ethical problems involved in incorporation of a radioisotope into DNA. 

The development of monoclonal antibodies which recognize halogenated pyrimidines such as 5-bromo-2-deoxyuridine (BrdU) incorporated into DNA (1) and of flow cytometric (FCM) techniques to simultaneously measure BrdU uptake and total DNA content (2) have led to a renaissance in cell kinetic studies. The speed and quantitative power of the flow cytometer, m conjunction with the specificity and sensitivity of monoclonal antibody techniques, provide the basis for the adoption and success of the BrdU technique in experimental and clinical investigations. 

The BrdU/FCM technique offers several advantages over 3HTdR/autorad-lography method in many cell kinetic studies. 

The results from a cell kinetic study can be obtained, literally, within 1 d using BrdU/FCM, whereas 3HTdR/autoradiography may take several weeks to obtain an answer. 

It is now possible to study routinely human tumor cell kinetic studies in vivo, because BrdU does not have to be a radioisotope as it is detected by a monoclonal antibody. BrdU shows no toxicity m the doses required for cell kinetic studies in humans. 

BrdU/DNA flow cytometry offers flexibility and diversity in the study of cell kinetics from cells in culture to human tumors in vivo. The essence of the procedure is to pulse label with BrdU by a short-term incubation in vitro or by a single injection in vivo samples are then taken at time intervals thereafter and stained after fixation in ethanol. The cells are then stained with a monoclonal antibody against BrdU that can be either directly conjugated to a fluoro-chrome (usually fluorescein isothiocyanate [FITC]) or, alternatively, bound to a second antibody conjugated with FITC. The cells are then counterstained with propidium iodide (PI) to measure the DNA content and analyzed on the flow cytometer. The results are displayed as linear-red fluorescence on the x-axis vs linear or log-green fluorescence on they-axis. 

To incorporate BrdU m vitro into monolayers or cell suspensions, the cells are incubated with 10-20 pM BrdU for 10—20 min Concentrations as small as 1 iM can be detected, whereas concentrations >50 xM may cause cell cycle perturbations. The BrdU is thoroughly washed out by two washes in PBS or medium. It is important to keep everything at 37°C for cell kinetic studies to avoid any perturbations caused by lowering the temperature. 

Wilson, G. D, McNally, N. J., Dische, S., Saunders, M. I., des Rochers, C, Lewis, A. A., and Bennett, M H. (1988) Measurement of cell kinetics in human tumours in vivo using bromodeoxyuridine incorporation and flow cytometry. Br J Cancer 58,423-431. 

If a certain process can produce a product, it is important to know how fast the process can take place. Kinetics deals with rate of a reaction and how it is affected by various chemical and physical conditions. This is where the expertise of chemical engineers familiar with chemical kinetics and reactor design plays a major role. Similar techniques can be employed to deal with enzyme or cell kinetics. To design an effective bioreactor... 

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