Diagnosis of cystic fibrosis

Gl. Gasparini, P., Novelli, G., Savoia, A., Dallapiccola, B., and Pignatti, P. R., First-trimester prenatal diagnosis of cystic fibrosis using the polymerase chain reaction Reports of eight cases. Prenatal Diagn. 9, 340-355 (1989). 

An important condition to be fulfilled in order to use the method for detection of sweat formation and its composition is that the electrodes are elec-trolytically in contact with each other. This is not a strict condition for urine detection and as an early-warning system for diabetes, because in these applications a qualitative detection is enough, and therefore one can start with dry electrodes. For diagnosis of cystic fibrosis, this is not possible because here a quantitative detection of salt concentration is expected. Therefore, one needs to start from a system with electrodes that are elec-trolytically in contact with each other right from the start of the experiment. For this purpose, water is immobilised in high-density cotton in which the conductive stainless-steel yarn electrodes are implemented. 

Carter, E.P., et al. 1984. Improved sweat test method for the diagnosis of cystic-fibrosis. Arch Dis Child 59 919. 

Q2 How is the sweat test for diagnosis of cystic fibrosis performed ... 

The analysis of sweat for increased electrolyte concentration is used to confirm the diagnosis of cystic fibrosis (CF). CF is recognized as a syndrome with a wide spectrum of clinical presentations associated with a defect in the cystic fibrosis transmembrane conductance regulator protein (CFTR), a protein that normally regulates electrolyte transport across epithelial membranes. (For a more detailed discussion of CF, see Chapter 40.) Several hundred mutations of CFTR have been identified. Although mutational analysis is available, it is not informative in all cases, and the sweat test remains the standard for diagnostic testing. ... 

Hammond KB, Turcios NL, Gibson LE. Clinical evaluation of the macroduct sweat collection system and conductivity analyzer in the diagnosis of cystic fibrosis. J Pediatr 1994 124 255-60. 

LeGrys VA. Sweat testing for the diagnosis of cystic fibrosis Practical considerations. J Pediatr 1996 129 892-7. 

Rosenstein BJ, Cutting GR. The diagnosis of cystic fibrosis A consensus statement. J Pediatr 1998 132 589-95. 

Webster HL. Laboratory diagnosis of cystic fibrosis. CRC Crit Rev Clin Lab Sci 1983 18 313-38. 

It is used in the diagnosis of cystic fibrosis. The chloridometer is also used in food and environmental laboratories. (Courtesy of Labconco Coip., Kansas City, MO.)... 

Some inherited disorders can be detected before birth. The prenatal diagnosis of cystic fibrosis is described on pages I.IS-1.19. 

Solid-state sensors for chloride, iodide, and fluoride are based on the solubility product of silver chloride or silver iodide particles in silicone rubber and a doped lanthanum fluoride single crystal, respectively. The fluoride-selective electrode was applied for the analysis of urine and bone tissue of people exposed to industrial sources as well as for control of therapeutic fluoride application for osteoporosis, whereas the chloride-selective sensor was applied to the analysis of sweat for the diagnosis of cystic fibrosis. In solid-state contact electrodes the solvent polymeric membrane is directly contacted to the solid field transducing element, although the reference electrode is separated from the ion-selective sensing pad. 

A proteolytic enzyme manufactured by the pancreas in the form of its zymogen, chjmiotrypsinogen. This is converted in the duodenum to chymotrypsin by another proteolytic enzyme, trypsin. Estimation of chymotrypsin in faeces can be of use in the diagnosis of cystic fibrosis, when enzyme secretion by the pancreas may be reduced. 

This is the migration of small ions in an electric field. The technique is used in the collection of sweat for the diagnosis of cystic fibrosis. The drug, pilocarpine, is made to migrate into the skin by means of electrodes placed on the skin. This drug stimulates sweat production which can be collected on filter paper and analysed for sodium or chloride. 

A drug that can be introduced into the skin by iontophoresis. It stimulates sweat secretion during the sweat test for the diagnosis of cystic fibrosis. 

A test that can be used for the diagnosis of cystic fibrosis (qv). In this condition there is a blockage in pancreatic and bronchial... 

The Use of Activation Analysis in Medicine.—The utilization of neutron activation techniques in medical and public health investigations has increased considerably in recent times. Reference was made earlier to the recent conferences devoted exclusively to applications in the investigation of environmental pollution and in the life sciences. The proceedings of the latter conference and the report of a panel meeting to discuss the uses of activation analysis in the study of mineral element metabolism give a good assessment of the current applications of activation techniques. Examples are the diagnosis of cystic fibrosis, the study of the role of trace elements in various diseases, and the measurement of iodine balance in man. The current in-... 

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