AMYLASE
Dotaz
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Acta Universitatis Carolinae. Medica. Monographia ; 1987/120
81 s. : obr.,tab.,bibliogr.
Total amylase activity in serum and urine is formed by pancreatic (P) and salivary (S) isoenzymes. The evaluation of isoamylases provides better information on enzyme changes during the disease than total activities alone. The resolution of pancreatic from extrapancreatic origin of hyperamylasemia may be clinically important. The experience obtained from the analysis of isoamylases in more than 1500 patients with different clinical diagnoses we compare with a contemporary knowledge of disturbances in amylase activities. We developed a method separating quantitatively both isoamylases on the mini-columns of ion-exchanger which we used in routine clinical investigation. In the first section we selected the findings on physiology and biochemistry of isoamylases. We described for the first time a significant decrease of P-isoamylase activity in serum during the intravenous infusions of hypertonic glucose, amino acids and during acute hypercalcaemia. We suggested that hypertonic glucose, amino acids and calcium may regulate directly or indirectly the amylase flux from acinar cells in the pancreas across basolateral membrane into blood. This endocrine secretion of amylase may be important in different clinical conditions in which changes of neurohumoral and/or hormonal regulation are developed. The isoamylase activities in patients with different diagnosis are analyzed in the clinical section. The results may be correctly evaluated only in connection with the pathogenesis of isoamylase changes. Disorders of the organs producing amylase (i.e. pancreas or salivary glands) may induce changes of isoamylases depending on their functional status. A progressive loss of amylase producing cells may be accompanied by a decrease of enzyme activity in serum as was described in chronic pancreatitis with exocrine insufficiency. However, the amylase activity in serum is significantly influenced by clearance mechanisms, too. Disorders of the liver or kidneys are accompanied predominantly with hyperamylasemia caused by the disturbed clearance mechanisms. The amylase activity in serum is a consequence of the result between input and output of the enzyme within the blood stream. Some humoral and hormonal regulations are able to modulate both processes in vivo. We suppose that pathogenetic standpoint has the main role for correct interpretation of isoamylase activities. The pathogenesis of hyperamylasemia is therefore discussed in single chapters. In conclusion, the isoamylase activities in serum and urine are influenced beside genetic background by many factors in health and disease which may be respected during the evaluation of the results.
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- chemie, klinická chemie
- biochemie
- patologie
- fyziologie
- MeSH
- amylasy krev MeSH
- elektroforéza MeSH
- izoenzymy analýza fyziologie MeSH
- karcinom enzymologie MeSH
- lidé MeSH
- nádory slinivky břišní enzymologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
Pancreatic α-amylase plays an important role in dietary starch hydrolysis in the small intestine and participates in enhanced glucose concentration after meals. It seems to be a problem for diabetic patients, who suffer from longer postprandial hyperglycemia after meal consumption than healthy people. There are commercially available drugs that inhibit α-amylase and thus reduce the postprandial hyperglycemia effect. However, these drugs may cause severe side effects. Conversely, some naturally occurring flavonoids were suggested to have an α-amylase-inhibiting effect without any side effects. There had been no rapid, undemanding method in terms of sample and reagent preparation that would enable screening of many potential inhibitors. Therefore, we developed an online capillary electrophoresis method to monitor α-amylase activity in the presence of an inhibitor. Each reaction constituent was introduced separately, directly into a capillary where the reagents were mixed by diffusion, which resulted in a 5-min analysis including conditioning of the capillary. We applied the method to test the inhibitory effect of flavonoid standards and their mixture and we investigated the inhibitory effect of ethanolic extract from Betula pendula bark. The developed method presents a faster and less expensive alternative to previously described offline methods. Graphical abstract Online CE screening of α-amylase inhibitors.
S rozvojom civilizačných chorôb, ako je diabetes mellitus, metabolický syndróm, prípadne obezita, rastie aj úsilie nachádzať nové liečivá predovšetkým z prírodných zdrojov. Patria medzi ne aj inhibítory α-amylázy, enzýmu, ktorý v tele zdravého človeka štiepi polysacharidy na jednoduchšie cukry. Vzhľadom k tomu, že toto štiepenie ovplyvňuje glykémiu, ktorú je snaha terapeuticky meniť, vzrastá aj záujem o tieto látky. Tento prehľadový článok mapuje druhy inhibítorov amylázy vrátane ich prírodných zdrojov.
Development of civilization diseases such as diabetes mellitus, metabolic syndrome or obesity, enforces the increasing effort to find new drugs, especially from natural sources. These include α-amylase inhibitors, which break down polysacharides into simple sugars in the body of a healthy person. As this cleavage affects the level of blood sugar, which is sought to be therapeutically influenced, there is a growing interest in these substances. This review maps the types of amylase inhibitors, including their natural resources.
- Klíčová slova
- rostlinné inhibítory, štěpení škrobu,
- MeSH
- alfa-amylasy antagonisté a inhibitory terapeutické užití MeSH
- amylasy * antagonisté a inhibitory terapeutické užití MeSH
- lidé MeSH
- škrob metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
- MeSH
- amylasy krev MeSH
- ductus thoracicus MeSH
- kardiopulmonální bypass MeSH
- lymfa enzymologie patofyziologie MeSH
- psi MeSH
- Check Tag
- psi MeSH
