Non-invasive technique

Griffiths-Johnson, D.A. and Karol, M.H., Validation of a non-invasive technique to assess development of airway hyperreactivity in an animal model of immunologic pulmonary hypersensitivity, Toxicology, 65, 283, 1991. 

In summary, chemiluminescence is a sensitive, non-invasive technique that can measure reactive oxidant production by small numbers of neutrophils indeed, neutrophil-derived chemiluminescence can be detected in as little as 5 fA of unfractionated human blood. The assay is suitable for automation using either multichannel luminometers or luminescence microtitre plate readers. Many researchers, however, have questioned the usefulness of this technique because of the uncertainty of the nature of the oxidant(s) that are detected. Nevertheless, in view of the recent developments made towards the identification of the oxidants measured and the assay s ability to detect intracellular oxidant production, it is has an important place in the phagocyte research laboratory. 

Spectrometer can measure the amount of glycogen from the content of C-labelled glucose in glycogen in Uver or muscle of a volunteer (for description of isotopes, see Appendix 2.2). This is a non-invasive technique, but it gives similar results to the biopsy method (Chapter 16) (Appendix 2.3). 

Applicable to invasive (for example when the patient is already catheterized) or non-invasive techniques. 

Detailed description of a porous microstructure is an essential prerequisite for unveiling the influence of pore morphology on the underlying two-phase behavior. This can be achieved either by 3-D volume imaging or by constructing a digital microstructure based on stochastic reconstruction models. Non-invasive techniques, such as X-ray micro-tomography, are the popular methods for 3-D... 

In order to reduce the technical expenditure of processing, the use of pumps for the transport of process fluids should be avoided, and such transport should be simply based on peristalsis or gravity feed, hence eliminating moving parts. For product analysis, sophisticated non-invasive techniques are proposed. 

Serup, J. A double-blind comparison of two creams containing urea as the active ingredient. Assessment of efficacy and side-effects by non-invasive techniques and a clinical scoring scheme. Acta Derm. Venereol. (Stockh.) 1992 177 (Suppl.) 34-43. 

High resolution l3C n.m.r. spectroscopy is a non-invasive technique that can be used to study metabolic pathways in intact organisms, organs or cells. Metabolism of l3C-enriched substrates may be followed spectroscopically for a number of hours. The rates of formation of metabolites can be monitored and end-products identified. This procedure provides the biochemist with a complete overview of the metabolism of a given substrate without destruction of the biological material and it has the additional advantage of enabling the observer to follow the metabolism of specific carbon nuclei and their metabolites. 

By using non-invasive techniques, it is possible to determine the concentration and oxidation state of vanadium in living cells. In A. ceratodes, EXAFS (X-ray absorption fine structure) techniques showed that 90% of the vanadium is in the form of V(III), 10% is V(IV)84. In A. nigra, EPR (electron paramagnetic resonance) spectroscopy showed that 95% of the vanadium is in the V(III) form, and 5% is V(IV)85. ... 

In addition, we have probed hydrolyzed Estane sample with the NMR Mobile Universal Surface Explorer (NMR MOUSE) (10). This technique is a quick non-invasive technique to determine the effect that polymer degradation has on its physical properties. Polymer chain mobility can be detected by proton spin-spin relaxation time measurements of hydrolyzed Estane using the NMR MOUSE. The spin-spin relaxation time decay curve shows increased chain mobility upon hydrolysis (Figure 11). The decay curve is fitted with a biexponential decay function to give two T2 values. The T22 associated with the more mobile polymer chains shows an inverse relationship to the molecular weight decrease as would be expected. This technique shows promise as an in situ probe of hydrolysis in high explosives in a non-destructive manner. 

Modern monitoring by both invasive and non-invasive techniques is complex and is undertaken in units dedicated to and, equipped for, this activity. The present comment is an overview. Monitoring will normally require close attention to heart rate and rhythm, blood pressure, fluid balance and urine flow, pulmonary gas exchange and central venous pressure. The use of drugs in shock is secondary to accurate assessment of cardiovascular state (especially of peripheral flow) and to other essential management, treatment of infection and maintenance of intravascular volume. 

Solid-state nuclear magnetic resonance (SSNMR) spectroscopy is a powerful technique used in the analysis of solids, and is currently finding more and more applications, particularly in the analysis of pharmaceutical formulations. It is a non-destructive, non-invasive technique that can be employed to simultaneously examine the physical and chemical states of both the active pharmaceutical ingredient (API) and the excipients present as they exist within the formulation. It is also highly selective, as nuclei of the API often have different chemical shifts than do common excipients. 

Rahman, I. and Kelly, F. (2003). Biomarkers in breath condensate a promising new non-invasive technique in free radical research. Free Radio Res 37, 1253-66. 

PAULUHN, J. EBEN, A. (1991) Validation of a non-invasive technique to assess immediate or delayed onset airway hypersensitivity in guinea pigs. Journal of Applied Toxicology, 11,423-431. 

Another assumption needed to accept serum level determinations as useful, is that the degree of toxicity is linearly related to the trough level. Current evidence does not support this correlation, since the early data of Schentag and coworkers [163] clearly demonstrated that the extent of renal uptake - which in turns will trigger toxicity - may vary widely among patients. What we actually need is a direct estimation of the amount of drug retained in the kidney, but that information is not easy to obtain by non-invasive techniques. 

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