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PubMed1983

Prevalence of normal serum amylase levels in patients with acute alcoholic pancreatitis.

Acute alcoholic pancreatitis is uncommonly diagnosed when the serum amylase level is normal. We defined acute alcoholic pancreatitis as a clinical syndrome in which hyperamylasemia was not a necessary component and sought support for the diagnosis by ultrasonography and computed tomography of the pancreas. In 68 episodes of acute alcoholic pancreatitis identified in a one-year period, the serum amylase level was normal at the time of hospital admission in 32%. In 40 episodes, we performed ultrasonography and computed tomography within 48 hr of admission. The diagnosis was supported by ultrasonography in 43%, by computed tomography in 68%. Ultrasonography and computed tomography supported the diagnosis as frequently in patients with normal serum amylase levels as in patients with hyperamylasemia. We conclude that patients with acute alcoholic pancreatitis frequently have normal serum amylase levels. The widespread clinical practice of relying solely on hyperamylasemia to establish the diagnosis of acute alcoholic pancreatitis is unjustified and should be abandoned.

Acute Disease↗

PubMed1986

Effect of somatostatin on amylase secretion from in vivo and in vitro rat pancreas.

In the present study the effect of somatostatin on amylase secretion was determined using in vivo cannulation and isolated acini from rat pancreas. In vivo somatostatin-14 inhibited amylase secretion in basal state and that stimulated with CCK8 and acetylcholine. Somatostatin-14 and somatostatin-28 failed to inhibit amylase secretion from isolated acini in basal state and that stimulated with CCK8 and bethanechol. Somatostatin-14 did not increase 45Ca uptake or efflux of label from acini preloaded with 45Ca. Cellular cyclic AMP levels were not significantly increased. Somatostatin-14 did not alter the synthesis of proteins in vitro, as judged by incorporation of a mixture of fifteen 14C-labeled amino acids. Somatostatin-14 stimulated phosphoprotein phosphatase in higher doses, whereas no effect was observed at lower doses. Inhibition of secretion in vivo and lack of stimulation of amylase secretion in isolated acini suggest that the somatostatin effect in vivo is mediated by an indirect effect similar to other peptides, for example, opiates and neurotensin. Stimulation of phosphoprotein phosphatase suggests that somatostatin may bind to the acinar cells and affect functions other than secretion and synthesis of enzymes.

Acetylcholine↗

PubMed1985

Effect of endorphins on amylase secretion from rat pancreas in vivo and in vitro.

The present study was done both in vivo by cannulating pancreatic duct of rats and in vitro using pancreatic slices and dissociated acini to determine the mode of action of endogenous opiate peptides on pancreatic acinar cell. Pancreatic slices were incubated with beta-endorphin or (Met)5-enkephalin alone and in combination with CCK8. Dissociated acini were incubated with naloxone, substance P, VIP, (Met)5- and (Leu)5-enkephalin and alpha-, beta-, and gamma-endorphin alone or in combination with CCK8. In vivo, both beta-endorphin and (Met)5-enkephalin did not alter basal secretion but inhibited CCK8-stimulated amylase secretion. This effect was not reversed by administration of naloxone. In the slices, neither beta-endorphin nor (Met)5-enkephalin altered basal or CCK8-stimulated secretion. In the dissociated acini, substance P and VIP significantly increased amylase secretion, whereas naloxone, enkephalins, and endorphins failed to alter amylase secretion. CCK8 increased amylase secretion greater than sixfold. In combination with enkephalins and endorphins, there was neither inhibition nor potentiation of CCK8 effect. These data indicate that the effect of opiate peptides on pancreatic acinar cells in the rat are nonspecific and appear not to be mediated by opiate receptors.

Amylases↗

PubMed1984

Regional assignment of human amylase (AMY) to p22----p21 of chromosome 1.

A human genomic DNA segment (lambda hal) which hybridizes with rat pancreatic amylase cDNA was used to regionally assign amylase genes in human-mouse somatic cell hybrids. The assignment of amylase genes to chromosome 1 was confirmed and regionally mapped to the short arm region p22.1----p21 using a cell hybrid retaining a translocation involving chromosome 1 [46,XX,t(1;2)(p21;q37)]. Restriction length polymorphisms at the amylase loci are reported for gene linkage studies.

Animals↗

PubMed1995

Recepto-secretory mechanism in histamine-stimulated amylase release from rat parotid gland.

The recepto-secretory mechanism in histamine-stimulated amylase release from rat parotid slices was studied using blockers of receptors and inhibitors of the intracellular messenger systems. Amylase release stimulated by histamine was inhibited by pyrilamine, an H1-receptor blocker, but not by cimetidine, an H2-receptor blocker. Atropine, prazosin and yohimbine had no effect on the release. Histamine-stimulated amylase release was inhibited by W-7, ML-9 and H-7, inhibitors of a calmodulin, a myosin light chain kinase (MLCK) and protein kinase C, respectively, while H-8, an inhibitor of protein kinase A, did not inhibit the release. These results suggest that histamine stimulation evokes amylase release via H1-receptors, followed by the Ca2+-dependent systems involving calmodulin, MLCK and protein kinase C.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1995

The effect of alpha-amylase on the acrosomal membrane of human sperm.

PURPOSE: Sperm capacitation and the acrosome reaction are prerequisites to accomplishing fertilization. The object of this research was to induce capacitation and the acrosome reaction of human sperm, comparing the acrosome status of fertile and infertile men, using alpha-amylase. METHODS: Acrosome status was measured using indirect immunofluorescence (IIF; monoclonal antibody GB24, Thèramex), hemizona assay (HZA), and transmission electron microscopy (TEM). RESULTS: Acrosome-reacted sperm without alpha-amylase treatment was significantly more abundant in the fertile versus the infertile group utilizing IIF, HZA, and TEM. alpha-Amylase-treated spermatozoa from the fertile and infertile groups showed a significant increase in the number of sperm bound to the hemizona (P < 0.05). CONCLUSIONS: The percentage of acrosome-reacted sperm in the infertile group was significantly enhanced by alpha-amylase, utilizing IIF and TEM.

Acrosome↗

PubMed1988

The amylase gene-enzyme system of chickens. I. Allozymic and activity variation.

Amylase allozymic and activity variation was studied in three flocks of chickens (Gallus domesticus). Individuals from one flock were studied to assess the effects of sex, tissue, and genotype on amylase activity. Additionally, the allozymes were purified and their specific activities compared. Variation was observed within and among the flocks. Two alleles were found to be segregating in the flocks, one flock being polymorphic and the other two monomorphic. Mean amylase activities among the three flocks were significantly different. The relationship of this activity variation to regulatory variation is discussed. There were no significant effects of sex or genotype on amylase activity and, in most cases, no correlation between activities in the various tissues. However, in heterozygotes one of the alloamylases had much lower activity than the other.

Amylases↗

PubMed1977

[The proteins of honey. III. Separation of honey amylase by hydrophobic partition chromatography (author's transl)].

Previous experiments to separate the amylase and "invertase" of honey by chromatography on sephadex-gels were unsuccesful. It was shown that honey-amylase, -like amylases form other sources -- has hydrophobic properties. Therefore it was possible to separate amylase-activity from other activities by means of hydrophobic affinity chromatography on phenyl-butylamine-Sepharose 4B.

Amylases↗

PubMed1996

Effects of saturated fatty acids on amylase release from exocrine pancreatic segments of sheep, rats, hamsters, field voles and mice.

Stimulatory effects of saturated fatty acids consisting of 4 (butyrate), 8 (octanoate), 12 (laurate) and 16 (palmitate) carbon atoms, as well as acetylcholine on pancreatic amylase release were assessed in tissue segments isolated from sheep, rats, hamsters, field voles and mice. The amount of amylase release induced by the fatty acids (1 mumol.l-1 to 10 mml.l-1) and by acetylcholine (10 nmol.l-1 to 100 mumol.l-1) increased in a concentration-dependent manner, and the maximum response in response to the fatty acids was obtained at the maximal dose used. The maximum increase in amylase release in response to butyrate or octanoate was highly and significantly (r = 0.974, P < 0.001) dependent on the log value of the mean body mass in the following order: sheep > rats > hamsters > field voles > mice. On the other hand, the response to laurate and palmitate was variable among animal species. Addition of atropine (1.4 mumol.l-1) to the medium did not reduce the responses to octanoate stimulation, but significantly reduced acetylcholine-induced responses, implying that the effects of the fatty acids were not mediated through activation of muscarinic acetylcholine receptors. Reduction of calcium ion concentration in the medium significantly inhibited the responses induced by the fatty acids and acetylcholine, suggesting that amylase release depends on extracellular calcium ions.

Acetylcholine↗

PubMed1991

Effect of protein kinase C on amylase secretion and cyclic AMP production in rat pancreatic acinar cells.

The authors examined the effects of protein kinase C on secretin-induced amylase release and cyclic AMP production in rat pancreatic acinar cells. Secretin (10(-6) M) and 12-O-tetradecanoyl-phorbol 13-acetate (TPA) (10(-6) M) induced 53% and 60% increase of amylase release from the basal level, respectively during 10 min. Simultaneous addition of TPA and secretin resulted in 42% amylase release from the basal level for 10 min. Suppression of secretin-induced amylase release was evident within 5 min of pretreatment with TPA. TPA showed the same effect on cyclic AMP production; secretin-induced increase of cyclic AMP was suppressed by pretreatment of TPA for 5 min. To explore the mechanism by which TPA inhibits secretin-induced cyclic AMP production, we also examined the effects of protein kinase C purified from rat brain on adenylate cyclase activity in pancreatic acinar membranes. Basal, forskolin- and secretin plus guanosine 5'-[gamma-thio]trisphosphate-stimulated adenylate cyclase activity were inhibited by protein kinase C in the presence of Ca++. These results suggest that protein kinase C might have a role in the inhibitory effect on adenylate cyclase in exocrine pancreas.

Adenylyl Cyclase Inhibitors↗

PubMed1995

Effect of protease inhibitors on peptide-stimulated amylase secretion from dispersed pancreatic acini.

Cholecystokinin (CCK) and bombesin stimulate dose-dependent amylase secretion from dispersed pancreatic acini. To establish whether cellular proteases can reduce secretion by degrading these regulatory peptides, the effect of protease inhibition on CCK and bombesin stimulated amylase secretion was investigated. A spectrum of protease inhibitors, including bacitracin, phenylmethylsulfonylfluoride, captopril, bestatin, phosphoramidon, and 1,10-phenanthroline, were investigated. Bacitracin (0.35 mM) increased the acinar amylase secretory response to CCK and bombesin substantially, suggesting that these two peptides are degraded by an endopeptidase from pancreatic acinar cells. In contrast, PMSF (1 mM) inhibited CCK and bombesin stimulated amylase release, suggesting a covalent interaction with this inhibitor and CCK or bombesin receptors. Other protease inhibitors either had minimal or no effects on acinar cell secretion. These results suggest bacitracin is a valuable enzyme inhibitor that can potentiate the effect of CCK and bombesin on acinar cells. In contrast, PMSF should be avoided when using these secretagogs to study pancreatic function.

Amylases↗

PubMed1994

Activation and stabilization of enzymes entrapped into reversed micelles. Studies on hydrolyzing enzymes--protease and alpha-amylase.

Observations of the activity of two hydrolyzing enzymes-protease and alpha-amylase--entrapped inside the reversed micelles formed by surfactants in hexane, benzene, and cyclohexane are reported. The surfactants chosen for this study are: Tween 80, a nonionic surfactant, Cetyl pyridinium chloride, a cationic surfactant, and two anionic surfactants, sodium lauryl sulfate and Aerosol OT. Tween 80 enhances the activity of both protease and alpha-amylase. Sodium lauryl sulfate and Aerosol OT, which are ionic surfactants, enhance the activity of protease, but inhibit the activity of alpha-amylase. Cetyl pyridinium chloride, however, enhances the activity of alpha-amylase, but inhibits the activity of protease. Enhanced activity is generally severalfold greater in comparison to the activity observed in the usual aqueous system in the absence of reversed micelles. It has also been observed that the enhanced activity of the enzymes entrapped inside the reversed micelles remains preserved for a much longer period of time in comparison to the activity in the usual aqueous systems. These observations, which support the view that with proper choice of surfactant and the organic solvent, reversed micelles act like a microreactor that provides a favorable aqueous micro-environment for enzyme activity, have biotechnological overtones.

Benzene↗

PubMed2001

Biochemical confirmation and characterization of the family-57-like alpha-amylase of Methanococcus jannaschii.

The gene encoding a family-57-like alpha-amylase in the hyperthermophilic archaeon Methanococcus jannaschii, has been cloned into Escherichia coli. Extremely thermoactive alpha-amylase was confirmed in partially purified enzyme solution of the recombinant culture. This enzyme activity had a temperature optimum of 120 degrees C and a pH optimum 5.0-8.0. The amylase activity is extremely stable against denaturants. Hydrolysis of large sugar polymers with alpha-1-6 and alpha-1-4 linkages yields products including glucose polymers of 1-7 units. Highest activity is exhibited on amylose. The catalyst exhibited a half-life of 50 h at 100 degrees C, among the highest reported thermostabilities of natural amylases.

Amino Acid Sequence↗

PubMed1989

Effects of CCK-8 in combination with natural or synthetic secretin on amylase, lipase, trypsin, and chymotrypsin secretion in rats.

In the present study, we examined the interaction between CCK-8 and natural or synthetic secretin on pancreatic enzyme secretion. On anaesthetized rats, a proximal duodenal segment was continuously perfused with saline and amylase, lipase, trypsin, and chymotrypsin were determined in the perfusate. Neither during iv saline nor during iv secretin (natural or synthetic) at doses of 0.01, 0.05, or 0.1 CU/kg/h, any of the four enzymes changed significantly from basal values over a period of 100 min. Iv CCK-8 at stepwise increasing doses of 5, 10, and 20 pmol/kg/h elicited a significant increase of all four enzymes at the medium dose, with a further increase of amylase and trypsin, but not lipase and chymotrypsin at 20 pmol/kg/h. The addition of secretin at all 3 doses potentiated CCK-induced trypsin output. The effects of natural secretin were more pronounced than those of the synthetic peptide. Secretin significantly increased amylase secretion over basal at the lowest dose of CCK-8 (5 pmol/kg/h) that by itself had no effect on amylase release. Only the higher doses of natural but not synthetic secretin augmented lipase secretion during the lowest dose of CCK-8. Both forms of secretin had no further stimulatory effect on CCK-induced chymotrypsin secretion. The present data demonstrate that, first, in rats a potentiation of CCK-8-induced enzyme secretion by low doses of secretin is different for the four enzymes, which suggests a differential regulatory action of these two intestinal hormones on pancreatic enzyme release. Second, the different effects of natural secretin may represent those of contaminants suggesting that only synthetic secretin should be employed in future studies of this peptide on pancreatic enzyme secretion.

Amylases↗

PubMed1994

The value of alpha-amylase and isoamylase determination in chronic renal failure patients.

Hyperamylasemia is a common finding in chronic renal failure (CRF) patients. It has been suggested that the diagnosis of acute pancreatitis in these patients is confirmed when serum amylase activities are greater than three times the upper normal limits. In order to evaluate the frequency, the type, and the hyperamylasemia levels in patients with various degree of chronic renal failure, the total serum amylase (Ta), the pancreatic (Pa) and salivary (Sa) types of serum isoamylases, as well as the urine isoamylases (Tu, Pu, Su, respectively) have been determined by the Phadebas method. Moreover, the levels of serum electrolytes and triglycerides were determined in order to study any relationship between serum electrolytes as well as triglycerides and alpha-amylase activities. We studied 102 patients of whom 33 (group A) had CRF with serum creatinine levels 8.5 +/- 3.1 mg/dL (mean +/- SD), 59 (group B) were receiving chronic hemodialysis, and 10 (group C) were on continuous ambulatory peritoneal dialysis as well as 47 normal individuals. None of the subjects studied had any clinical manifestation of acute pancreatitis. Our results showed that the Ta, Pa and Sa levels of groups A, B, and C were significantly elevated compared to normal subjects. Eighteen patients had Pa activities greater than three times the upper normal limits. In the present study, no relationship between serum electrolytes as well as triglycerides and alpha-amylases was found. In conclusion, hyperamylasemia was a much more common finding in CRF patients than previously reported in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed2005

Constitutive alpha-amylase producing mutant and recombinant haploid strains of thermophilic fungus Thermomyces lanuginosus.

Morphological, developmental and antimetabolite-resistant mutants of T. lanuginosus were characterized and used for screening with the aim to develop constitutive alpha-amylase-hyperproducing strains. The protoplast fusion of two spontaneous mutants of T. lanuginosus, characterized as asporulating and resistant to 2-deoxy-D-glucose (2DG), resulted in sporulating, 2DG sensitive heterokaryotic fusants. A recombinant haploid strain F64fB developed there from produced alpha-amylase constitutively in glucose-containing medium. Constitutive alpha-amylase-hyperproducing mutant (III8) obtained after cyclic mutagenesis and screening yielded approximately 20 fold more alpha-amylase in a glycerol-containing medium than the wild strain.

Ascomycota↗

PubMed2003

Highly variable polymorphism of the alpha-amylase gene family in Litopenaeus vannamei (Crustacea Decapoda).

Alpha-amylase from the tropical shrimp Litopenaeus vannamei presents a high degree of polymorphism and at least eight different electromorphs are detected by electrophoresis. Based on nucleotide sequences, three cDNAs have been previously characterized. In this paper we report on the organization and the evolution of corresponding alpha-amylase genes, determined after PCR amplification. Three AMY genes have been characterized, spanning over 3.3 kb and encoding mature proteins of 495 amino acids (aa), which are all expressed in the digestive gland. The existence of nine short introns, ranging from 86 to 454 bp, located at the same positions for each of the different genes, and presenting no similarity between them, is reported. Between 11 and 15% of changes are observed in the coding aa sequences of genes II and III compared to the gene I sequence respectively. One 5' putative promoter sequence has been sequenced and shows no classical TATA box upstream to the coding sequence. Based on the intron size difference, a single PCR (producing the S-R fragments) allows the separation of a partial gene I (750 bp), corresponding to cDNA 20, from the others (650-680 bp). Sequencing different S-R PCR fragments from one shrimp shows at least eight different haplotypes. A complex microsatellite repeat is present in intron 6 of gene II. Using size and sequence differences in this repeated portion, it is possible to characterize two gene subfamilies (IIa and IIb) encoding previously described cDNAs 28 and 37, respectively. For the gene II family, two to four alleles are present in one shrimp corresponding to these two genes. Within the Panama natural population, 35 different alleles are shown at this locus. Regarding alpha-amylase gene structure in the shrimp, many recombinants are present from a set of individuals and constitute an important mechanism of evolution of alpha-amylase function.

Amino Acid Sequence↗

PubMed2003

Studies on a thermostable alpha-amylase from the thermophilic fungus Scytalidium thermophilum.

An alpha-amylase produced by Scytalidium thermophilum was purified using DEAE-cellulose and CM-cellulose ion exchange chromatography and Sepharose 6B gel filtration. The purified protein migrated as a single band in 6% PAGE and 7% SDS-PAGE. The estimated molecular mass was 36 kDa (SDS-PAGE) and 49 kDa (Sepharose 6B). Optima of pH and temperature were 6.0 and 60 degrees C, respectively. In the absence of substrate the purified alpha-amylase was stable for 1 h at 50 degrees C and had a half-life of 12 min at 60 degrees C, but was fully stable in the presence of starch. The enzyme was not activated by several metal ions tested, including Ca(2+) (up to 10 mM), but HgCl(2 )and CuCl(2) inhibited its activity. The alpha-amylase produced by S. thermophilum preferentially hydrolyzed starch, and to a lesser extent amylopectin, maltose, amylose and glycogen in that order. The products of starch hydrolysis (up to 6 h of reaction) analyzed by thin layer chromatography, showed oligosaccharides such as maltotrioses, maltotetraoses and maltopentaoses. Maltose and traces of glucose were formed only after 3 h of reaction. These results confirm the character of the enzyme studied to be an alpha-amylase (1,4-alpha-glucan glucanohydrolase).

Ascomycota↗