Measurement of plasma amylase activity

Sewage Protein Information Mining: Discovery of Large Biomolecules as Biomarkers of Population and Industrial Activities

Wastewater-based epidemiology has been revealed as a powerful approach for surveying the health and lifestyle of a population. In this context, proteins have been proposed as potential biomarkers that complement the information provided by currently available methods. However, little is known about the range of molecular species and dynamics of proteins in wastewater and the information hidden in these protein profiles is still to be uncovered. In this study, we investigated the protein composition of wastewater from 10 municipalities in Catalonia with diverse populations and industrial activities at three different times of the year. The soluble fraction of this material was analyzed using liquid chromatography high-resolution tandem mass spectrometry using a shotgun proteomics approach. The complete proteomic profile, distribution among different organisms, and semiquantitative analysis of the main constituents are described. Excreta (urine and feces) from humans, and blood and other residues from livestock were identified as the two main protein sources. Our findings provide new insights into the characterization of wastewater proteomics that allow for the proposal of specific bioindicators for wastewater-based environmental monitoring. This includes human and animal population monitoring, most notably for rodent pest control (immunoglobulins (Igs) and amylases) and livestock processing industry monitoring (albumins).

α-Amylase assay with starch-iodine-sodium fluorescein-based fluorometric method in human serum samples

A new fluorometric method was developed for the determination of α-amylase activity in human serum samples. Firstly, a saturated starch-iodine complex (SI) was prepared. The SI complex was combined with sodium fluorescein to form a starch-iodine-sodium fluorescein complex (SIF). As the SIF complex decomposes with the α-amylase enzymatic hydrolysis of starch, the intensity of its fluorescence emission increases. The α-amylase activity is determined using the increased fluorescence emission intensity following hydrolysis of the SIF complex by α-amylase. The optimum pH, optimum buffer concentration, optimum temperature, and interference effect were identified for the developed fluorometric measurement method. Under the optimum conditions, a linear calibration curve was obtained between 0.18 and 9.00 U/L for α-amylase. The α-amylase activity in the human serum sample was also determined by our prepared measurement system and compared with the result from a medical center. Both methods are in good agreement with each other. Because this newly developed fluorometric method for α-amylase activity in serum samples is inexpensive, easy to use, and carried out to detect a very low amount of human serum α-amylase with sensitivity, it can be proposed this method for alpha-amylase activity assay in all other biological samples.

Determination of total and pancreatic alpha-amylase in human serum with 2-chloro-4-nitrophenyl-alpha-D-maltotrioside as substrate

A reagent and assay conditions for the determination of the catalytic concentration of alpha-amylase (E.C. 3.2.1.1) in serum with 2-chloro-4-nitrophenyl-alpha-D-maltotrioside as substrate are described. The selected reaction mixture contains 50 mmol/l 2-(N-morpholino)ethanesulfonic acid buffer at pH 6.1 (37 degrees C), 300 mmol/l sodium chloride, 5 mmol/l calcium chloride and 450 mmol/l potassium thiocyanate. The described method is suitable for the measurement of total as well as pancreatic alpha-amylase by including antibodies against the salivary isoenzyme. The method shows the absence of a lag phase period, is sensitive and precise, has a large analytical range and is free from interference by hemoglobin, bilirubin and triglycerides. Comparative studies showed good correlation with other well established methods.

Chromatographic methods for amylases

This review surveys recent developments in chromatographic methods for the separation of amylases from complex extracts, including the separation of isozymes. It contains two tables with the properties and molecular characteristics of alpha-and beta-amylases from different sources as well as an updated review of methods for the determination of amylase activity. The main subject of this review is a detailed evaluation of the application of newly developed chromatographic methods for the purification of amylases.

Measurement of bicarbonate output from the intact human oesophagus

Injury of the oesophageal mucosa can result from exposure to refluxed gastric acid and pepsin. Competence of the lower oesophageal sphincter and peristaltic activity serve to reduce contract time between luminal acid and oesophageal mucosa, but intraluminal neutralisation of residual acid by bicarbonate may also be important in preventing oesophageal mucosal injury. Whereas swallowed saliva contains bicarbonate, recent experiments have also demonstrated alkali secretion from the mammalian oesophagus. Bicarbonate secretion from the human oesophagus was therefore examined with an intubation technique and perfusion of the oesophagus with a non-absorbable marker. Saliva, gastric, and oesophageal aspirates were collected and bicarbonate concentrations determined by measurements of pH and pCO2 or by back titration. In 32 normal subjects (17 women, 15 men) median basal oesophageal bicarbonate secretion determined by a pH/pCO2 method was 416 (range 139-1050) mumol/hour/10 cm. In a subgroup of 15 experiments median oesophageal bicarbonate output was 489 (range 157-1033) mumol/hour/10 cm (pH/pCO2 method) compared with a median alkali output of 563 (range 135-799) mumol/hour/10 cm as determined by back titration. The difference was not significant. Salivary contamination of the oesophagus accounted for 25% of all bicarbonate measured within the oesophagus and refluxed gastric bicarbonate accounted for 2.5%. Bicarbonate secretion from the normal human oesophagus may, in combination with swallowed salivary bicarbonate, play a part in preventing oesophageal mucosal damage due to refluxed gastric acid and pepsin.

Serum enzymes and other laboratory tests in acute pancreatitis

This review evaluates selective enzymes and blood tests available for the diagnosis and prognosis of acute pancreatitis. It is concluded that serum amylase and lipase measurements represent the best available diagnostic methods. Newer alternative assays still require careful evaluation.

Acute pancreatitis and normoamylasemia. Not an uncommon combination

A consecutive series of 352 attacks of acute pancreatitis (AP) was studied prospectively in 318 patients. AP was ascertained by contrast-enhanced CT scan in all but four cases in which diagnosis was made at operation or autopsy. Sixty-seven of these cases (19%) had normal serum amylase levels on admission (i.e., less than 160 IU/L, a limit that includes 99% of control values), a figure considerably higher than generally admitted. When compared to AP with elevated serum amylase, normoamylasemic pancreatitis was characterized by the following: (1) the prevalence of alcoholic etiology (58% vs. 33%, respectively, p less than 0.01), (2) a greater number of previous attacks in alcoholic pancreatitis (0.7 vs. 0.4, p less than 0.01); and (3) a longer duration of symptoms before admission (2.4 vs. 1.5 days, p less than 0.005). In contrast AP did not appear to differ significantly in terms of CT findings, Ranson's score, and clinical course, when comparing normo- and hyperamylasemic patients, although there was a tendency for normoamylasemic patients to follow milder courses. Serum lipase was measured in 65 of these normoamylasemic cases and was found to be elevated in 44 (68%), thus increasing diagnostic sensitivity from 81% when amylase alone is used to 94% for both enzymes. A peritoneal tab was obtained in 44 cases: amylase concentration in the first liter of dialysate was greater than 160 IU/L in 24 cases (55%), and lipase was greater than 250 U/L in 31 cases (70%). Twelve of these 44 cases had low peritoneal fluid and plasma concentrations for both enzymes. Thus little gain in diagnostic sensitivity was obtained when adding peritoneal values (96%) to serum determinations. AP is not invariably associated with elevated serum amylase. Multiple factors may contribute to the absence of hyperamylasemia on admission, including a return to normal enzyme levels before hospitalization or the inability of inflamed pancreases to produce amylase. Approximately two thirds of cases with normal amylasemia were properly identified by serum lipase determinations. AP does not appear to behave differently when serum amylase is normal or elevated, and should therefore be submitted to similar therapeutic regimens in both conditions.