Amylase Excretion Research Articles

Perfusion imaging of pancreas allografts using technetium-99m hexamethyl propylene amine oxime.

The vascular integrity and major changes in perfusion can be determined by visual interpretation of radionuclide flow studies. We studied the potential of a new radiopharmaceutical technetium-99m hexamethyl propylene amine oxime (99mTc-HMPAO) in the particular setting of pancreas transplantation. Perfusion was measured by perfusion indices (PI). Changes in graft perfusion were estimated by three independent observers. A predefined scale from 0 to 4 was used, with 0 representing no visualisation of the graft and 4 denoting sharp countour delineation and distinct demarcation from the background. In order to investigate the relation between perfusion of the pancreas graft and its exocrine function, we measured the amylase excretion rate (AER) in the urine, expressed in units per hour. It is concluded that 99mTc-HMPAO is a suitable radiopharmaceutical for pancreas allograft imaging. For the assessment of the vascular integrity in the direct postoperative period, the scintigram is very reliable. Although a correlation between exocrine function of the graft and the perfusion score was not established, it is possible to make a clear sorting of AER measurements into different groups.

Increased urinary zinc excretion after thermal injury.

Urinary zinc excretion normally plays a minor role in zinc homeostasis; however, urinary zinc excretion is markedly elevated after trauma or surgery, and mechanism(s) for this zinc loss are poorly defined. In this study we evaluated multiple potential mechanisms for increased urinary zinc excretion in patients with thermal injury. We documented that patients with severe thermal injury had markedly elevated urinary zinc excretion. Above 20% total body surface area burn, however, the severity of thermal injury did not correlate with urinary zinc excretion. Serum zinc concentrations were depressed on initial evaluation and gradually increased during the hospital course, whereas peak urinary zinc excretion occurred 2 to 5 weeks after injury. Thus the depression in serum zinc concentration did not temporally relate to the observed pattern of hyperzincuria. Increased urinary zinc excretion also did not temporally relate to urinary excretion of the amino acids cysteine and histidine (both of which tightly bind zinc) nor to urinary 3-methylhistidine excretion, a marker of muscle breakdown. Urinary amylase excretion, a marker of renal tubular dysfunction, did follow the pattern of urinary zinc loss to some extent, although this correlation was not perfect. Increased oral intake of zinc via zinc supplements resulted in significantly increased urinary zinc excretion. Patients receiving total parenteral nutrition (TPN) did not have significantly increased urinary zinc excretion when compared with people receiving their total nutrient intake by mouth.(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary Kallikrein Excretion in Chronic Pancreatic Diseases

Variations in urinary kallikrein in pancreatic diseases were ascertained, and possible influencing factors were investigated. Serum amylase and urinary excretion of glandular kallikrein, pancreatic ribonuclease (RNase), gamma-glutamyltransferase (GGT) and amylase were measured in 24 control subjects, 39 patients with pancreatic cancer, 49 with pancreatitis and 63 with extra-pancreatic diseases. Urinary kallikrein was found to be elevated in a substantial number of patients with pancreatitis. Higher levels were detected in patients with a relapse, which was diagnosed using clinical and biochemical examinations. RNase was also increased in a high number of patients with pancreatic diseases, but was not correlated with pancreatic damage. In patients with pancreatitis, a correlation was found between urinary kallikrein and RNase excretions. No correlations were found between kallikrein and serum or urinary amylase and GGT. We can conclude that urinary kallikrein excretion increases in pancreatitis, especially when a phlogistic involvement of the pancreas is present; this condition may lead to a release of this ultrafiltrable enzyme in the circulation. Renal tubular damage, which determines a reduced reabsorption of this enzyme, seems to play a concomitant but minor role in this process.

Diabetic Strain (WBN/Kob) of Rat Characterized by Endocrine-Exocrine Pancreatic Impairment Due to Distinct Fibrosis

A spontaneously developed endocrine-exocrine pancreatic dysfunction was observed in the aged males of an inbred strain of Wistar rats, WBN/Kob. Nonobese male WBN/Kob rats developed glycosuria and hyperglycemia at around 9 months of age. Cumulative incidence of diabetes in male rats was 43% (33 of 76) at 12 months of age and reached 90% at the age of 21 months. In contrast, female rats did not become diabetic. Urinary excretion of amylase in WBN/Kob rats was significantly increased in comparison with control Wistar rats. Moreover, the exocrine pancreatic function test was impaired in WBN/Kob rats. Pathological examination of pancreata revealed infiltration of inflammatory cells, hemorrhage, deposition of hemosiderin, and fibrinous exudation around pancreatic ducts and blood vessels at 3 months of age. A gradual increase of fibrous tissue into the exocrine tissue and islets was observed with advancing age. The extremely enlarged interlobular lymph nodes were also observed. At the age of 12 months, the fibrous tissue replaced extensive areas of the pancreas and involved islets. The amylase content of pancreata in WBN/Kob rats was markedly decreased in comparison with that in Wistar rats at 12 months of age. Islets composed of few endocrine cells were detected. Immunohistochemical staining for insulin and glucagon showed a decreased number of not only B cells but also A cells. Moreover, both the pancreatic insulin and glucagon contents were markedly decreased in WBN/Kob rats in comparison with Wistar rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative evaluation of the diagnosis of acute pancreatitis based on serum and urine enzyme assays

We compared the diagnostic sensitivities of serum amylase, lipase (assayed enzymatically and immunologically), trypsinogen and elastase-1, the 2-h-timed urine amylase excretion and the ratio of amylase and creatinine clearances in the recognition of acute pancreatitis. Serial serum and urine findings from 39 patients with acute pancreatitis, and from 42 patients with non-pancreatic causes of abdominal pain (controls), as well as findings from 24 healthy subjects (normals) were studied. Decision thresholds were established for each parameter using either the control or the normal population, and the resulting diagnostic sensitivities determined. On hospital admission, all serum assays were equally sensitive, but on subsequent days lipase, trypsinogen and elastase-1 assays all significantly surpassed the sensitivity of the serum amylase assay. On the second and subsequent hospitalization days, determination of timed urine amylase excretion offered no advantage over the serum amylase, and the ratio of amylase and creatinine clearances lacked discrimination altogether.

DIFFERENTIAL DIAGNOSIS OF HYPOAMYLASURIA IN PANCREAS ALLOGRAFT RECIPIENTS WITH URINARY EXOCRINE DRAINAGE

We have studied the histopathologic correlates of a significantly decreased urinary amylase excretion rate (UAER) to determine its reliability in predicting the presence of cellular rejection within pancreas allografts drained via a duodenocystostomy. Significant hypoamylasuria in pancreas allograft recipients was defined as a diminution of greater than 50% in UAER sustained for greater than 36 hr and not associated with a decrease in serum amylase activity. We observed 18 such episodes of hypoamylasuria in 13 of 18 patients receiving pancreas allografts. Pancreaticoduodenal material was obtained during 11 of these episodes, one attempt failed, and for the remaining 6 episodes we obtained 3 renal allograft biopsy specimens. Histopathologic examination of the 14 specimens revealed cellular rejection in 9 (64%), fibrosis in 2 (14%), enzymatic necrosis in 1 (7%), cytomegaloviral pancreatitis in 1 (7%), and no abnormal features in 1 (7%). During these 14 episodes, a genetically identical renal allograft was present for 11 and showed signs of dysfunction in 9; however, the pancreatic histologic features suggested rejection in only 7 of the 9. Thus even the combination of hypoamylasuria and renal dysfunction in recipients of genetically identical organs was not fully reliable in predicting pancreas allograft rejection. In addition, the interval between organ implantation and onset of hypoamylasuria did not predict the histologic diagnosis. As with other solid-organ allografts, biopsy is a useful adjuvant for determining patient management in the presence of organ dysfunction.

Enzyme depletion in insect feeding experiments: Fact or artifact?

1. 1. Musca domestica larvae were fed polyacrylamide gels to induce starvation and subsequently were fed starch gels. 2. 2. Amylase activity decreased in midgut cells during starvation and increased on refeeding, whereas in midgut contents it decreased along the whole experiment. 3. 3. The majority of the luminal amylase is soluble, although in refed larvae there is a significant amount which is pelleted on centrifuging. 4. 4. The calculated values for amylase activity remaining in midgut content of starved and refed larvae, taking into account literature data for amylase excretion in M. domestica larvae, agreed with the experimental values. 5. 5. The results suggest that amylase excretion in the absence of amylase secretion is the main event causing the decrease of amylase activity on refeeding. 6. 6. Another important event is the co-sedimentation of amylase with starch during homogenate clearing by centrifugation. 7. 7. These explanations probably also hold for other luminal hydrolases, making unnecessary the misleading concept of “enzyme depletion by the substrate”.

APPEARANCE OF TYPE II DIABETES MELLITUS IN TYPE I DIABETIC RECIPIENTS OF PANCREAS ALLOGRAFTS

To determine the cause of hyperglycemia appearing after pancreas transplantation in type I diabetic recipients, we performed 65 oral glucose tolerance tests with serum insulin and C-peptide determinations in 32 patients with pancreas grafts functioning two or more months following transplantation. We correlated these results with estimates of graft size obtained by magnetic resonance imaging (MRI) and values of urinary amylase as a measure of pancreatic exocrine function. A total of 33 studies were obtained in 20 patients at times of normal glucose tolerance, and normal ranges for serum insulin and C-peptide levels were established; 32 studies in 17 patients during periods of glucose intolerance revealed values of serum insulin and C-peptide that were within the normal range, though the time to peak values was delayed to 2 hr, characteristic of type II diabetes. Only 3 of 17 patients examined by MRI had significant pancreatic allograft atrophy. These patients also had low urinary amylase excretion, and the only values for serum C-peptide that were below the normal range. The other 14 hyperglycemic patients had normalized pancreas grafts, normal urinary amylase excretion, and normal values for serum insulin and C-peptide. In our experience, then, in 76% of patients with hyperglycemia more than 2 months following pancreas transplantation, the cause was appearance of type II diabetes rather than destruction of the allograft with recurrence of type I diabetes. This observation has important implications for the definition of pancreas allograft failure and for the management of pancreas allograft recipients with hyperglycemia.

The Influence of Hydrochlorothiazide and Tripamide on Serum and Urinary Amylase

Pancreatitis and asymptomatic elevations of serum amylase have been reported after therapy with thiazide diuretics. In the current study, the effects of hydrochlorothiazide and tripamide treatment on serum and urinary amylase excretion were investigated in 12 hypertensive volunteers. Two patients developed modest elevations of the serum amylase above the normal range after 12 weeks of treatment with hydrochlorothiazide 50 mg daily, but the mean serum amylase did not change. Hydrochlorothiazide did not produce a statistically significant increase in urinary amylase excretion but did reduce the ratio of salivary amylase/creatinine clearance in a two-hour urine collection. Tripamide 10 mg daily had no effect on serum or urinary amylase.

Amylase in urine as measured by a single-step chromolytic method.

We studied a new single-step direct chromolytic method (Behring D.A.T.) for measuring urinary amylase (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) activity, comparing results with those by a similar, but two-step, procedure that requires an auxiliary (coupling) enzyme. The two methods gave virtually identical relative responses to purified human pancreatic and salivary amylases. Assay of four quality-control materials to evaluate the total (day-to-day) precision of the new method yielded CVs of 4 to 7%, similar to those of the comparison method for each of the four quality-control samples. Amylase activity was measured by both methods in 110 random (i.e., untimed) urine specimens. Linear regression analysis provided a slope and y-intercept of 0.947 and 4 U/L (x = comparison method, y = direct method), respectively, and a standard error of the estimate of 25 U/L for specimens in which the amylase activities ranged from 11 to 1465 U/L (mean = 358 U/L) by the comparison method. The mean rate of amylase excretion in 2-h timed urine specimens from 95 healthy volunteers, as measured by the new method, was 7.18 (SD = 3.18) U/h, and the nonparametric (95% confidence interval) reference interval was 1.6 to 15.2 U/h. We consider the new method a promising alternative to other kinetic assays that require the use of auxiliary enzymes.

Renal clearance of pancreatic and salivary amylase relative to creatinine clearance in patients with renal disease and proteinuria.

To study the charge-selective properties of the glomerular filter in renal disease, we measured the fractional clearance, relative to creatinine clearance (ECC), of the amylase isoenzymes pancreatic amylase and salivary amylase, which have identical size but different charge. In 63 healthy subjects the mean (and SD) fractional excretion of pancreatic amylase, 4.07% (1.24%), was fourfold that of salivary amylase: 1.02% (0.54%). For 29 patients with renal disease and proteinuria, the mean fractional excretion of pancreatic amylase was significantly lower, 3.31% (1.94%), and that of salivary amylase significantly higher, 2.06% (1.41%), than in controls. In these patients, fractional excretions of both these isoenzymes were negatively correlated with urinary excretion of beta 2-microglobulin and ECC. Evidently, differences in clearances of pancreatic and salivary amylase are a consequence of differences in charge-related glomerular filtration. The relative increase of salivary amylase clearance in patients with renal disease and proteinuria is most probably caused by a loss of the charge-selective properties of the glomerular basement membrane.

Effect of tannins on growth and amylase production by Calvatia gigantea

The effect of tannins was investigated on growth and α-amylase (α-1,4-glucan 4-glucanohydrolase, EC 3.2.1.1) production by the edible fungal species Calvatia gigantea, grown in a laboratory-scale fermenter on acorn starch media containing up to 2 g tannins l −1. No inhibition of both growth and amylase excretion was observed when the fungus was cultivated on media containing 40 to 100 times higher tannin concentration than that reported to inhibit microbial growth. Amylase excretion was enhanced when starch was dry sterilized but specific growth rate was higher when starch was wet sterilized. Biomass and amylase production increased with increasing substrate concentration and specific growth rate reached its maximum value at 20 g l −1 starch concentration. The optimum pH of biomass and amylase productionwas 5.0–5.5 and 6.0−6.5 respectively and that of temperature was 29–32 and 29–30°C respectively. Maximum yields of 68 250 U amylase and 0.58–0.60 g biomass g −1 acorn were obtained at optimum growth conditions. A plot of reciprocal growth rate vs. reciprocal starch concentration made it possible to calculate K s = 0.84 g acorn starch l −1 and μ max = 0.249 h −1.

Effect of amino compounds on alkaline amylase production by alkalophilic Bacillus sp.

Of the amino compounds investigated, β-alanine, dl-norvaline and d-methionine were effective for the production of alkaline amylase by alkalophilic Bacillus no. A-40-2. The addition of 0.5% dl-norvaline and 0.5% d-methionine to the culture medium increased amylase production 1.7-fold, while they repressed growth slightly or strongly. There was no relation between amylase yield and the extracellular protein amount. Because alkaline protease activity was negligible in the culture fluid, these compounds might change the regulation of amylase synthesis and/or make amylase excretion easier.

Amylase excretion after exercise.

Increase in amylase excretion in the urine in response to 8 days of aerobic running is delayed until after the athletes have rested for 24-48 h. In contrast, the amylase creatinine ratio is increased immediately after intense short-term exercise. The mechanism for these differences is unknown, but the timing of the amylase excretion pattern after long- and short-term exercise is similar to the urinary amylase after continuous and single bolus intravenous glucagon.

Proximal renal tubular dysfunction in severe burns.

Proximal renal tubular function was studied in 11 patients with severe burn injury. Creatinine clearance was normal or increased in ten patients. Fractional excretion of sodium was less than 1% in ten. Fractional excretion of uric acid and amylase were increased in all but four and two cases, respectively, while absolute clearances of lysozyme and beta 2-microglobulin were increased in all but one patient. Renal threshold phosphate concentration was reduced in four patients. Twenty-four-hour urine glucose excretion exceeded 1 g in five patients, aminoaciduria was noted in eight, and proteinuria, predominantly globulinuria, was present consistently. Metabolic acidosis was seen in one patient, and transient hypokalemia occurred in two. Abnormalities of proximal tubular function were more marked in the five patients with the greatest extent of third-degree burns who died. The cause of proximal tubular dysfunction is not clear and may be related to an adaptive response to severe injury.

Inhibitory action of thyrotropin-releasing hormone on serum amylase activity and its mechanism.

The effect of im administration of 500 micrograms TRH on serum amylase activity was studied in 34 normal women, 6 women with primary hypothyroidism, 1 woman with anorexia nervosa, 6 women with hyperthyroidism due to Graves' disease, and 5 women with renal failure on chronic hemodialysis. Serum amylase activity decreased significantly in 31 of 34 normal subjects 60 to 120 min after administration of TRH. However, amylase isoenzymes were not significantly affected after administration of TRH, suggesting that TRH equally affects pancreatic and salivary amylase activity. TRH was also effective in patients on chronic hemodialysis, indicating that TRH does not reduce serum amylase activity by increasing urinary excretion of amylase. Since TRH reduced serum amylase activity in hyperthyroid patients in whom TRH failed to stimulate TSH secretion, TRH does not reduce serum amylase activity through increased secretion of TSH. The action of TRH was not mediated by serum thyroid hormone levels since TRH was similarly effective in patients with hypothyroidism or hyperthyroidism. TRH did not inhibit or interfere with amylase determination when added in vitro to heparinized blood. Perfusion of the dog pancreas with TRH reduced amylase activity in pancreatic juice and pancreatic venous blood. The magnitude of the decrease was related to the dose of TRH used. Since decrease in amylase activity of the pancreatic juice preceded that in pancreatic venous blood, TRH probably directly acts on the pancreas to reduce amylase secretion. As a result, serum amylase activity decreased after administration of TRH.

Effect of intravenous fat emulsion on experimental acute pancreatitis.

The known relationship of hyperlipidemia and pancreatitis raises the question whether intravenous fat emulsion is detrimental in acute pancreatitis. Pancreatitis was induced in 52 male Sprague-Dawley rats followed by placement of a jugular catheter which was anchored to the back with a Teflon button. The animals were placed NPO in metabolic cages and continuously infused, initially with normal saline. The 37 animals surviving 24 hr were randomly assigned to group I (mean iv intake: glucose 222 kcal/kg/day; amino acids 13.1 g/kg/day) or group II (glucose 191 kcal/kg/day; intravenous fat emulsion 10% 47 kcal/kg/day; amino acids 12.9 g/kg/day). Nine animals were eliminated from the study because of mechanical problems leaving 14 in each group for analysis. Per cent survival on days 3, 5, and 7 was 64, 50 and 36 in group I, and 50, 36 and 36 in group II. Mean urinary amylase excretion was 244 +/- 185 units/day in group I and 262 +/- 127 units/day in group II. There was no significant difference in survival or urine amylase excretion nor in pancreatic histology or gross appearance of the animals between the two groups. In this model of acute pancreatitis, intravenous fat emulsion was not detrimental as measured by survival, urinary amylase excretion, and pancreatic histology.

Fate of circulating isoamylases in the rabbit.

Amylase purified from the pancreas and parotid gland of rabbits was labeled with 125I. Plasma disappearance was biexponential after bolus injection. Half-time of metabolic clearance was 97 and 95 min, respectively, for pancreatic and salivary 125I-amylase. About 20 and 30% of the injected pancreatic and salivary 125I-amylase, respectively, appeared intact in the urine within 24 h. Organs were assayed for radioactivity at specified times. No organ at any time contained more than 20% of injected radioactivity. At 24 h, more than 90% of radioactivity in organs was acid soluble. Bilateral nephrectomy significantly slowed plasma disappearance, although 90% hepatectomy did not. These studies in the rabbit indicate that 1) homologous isoamylases are cleared from plasma at rates comparable with those reported in primates; 2) in contrast to primates, urinary excretion of salivary amylase is greater than pancreatic amylase; and 3) within 24 h, virtually all of injected 125I-labeled isoamylases were catabolized or excreted.

Relation between respiration, excretion (ammonia and inorganic phosphorus) and activity of amylase and trypsin in different species of pelagic copepods from an Indian Ocean equatorial area

The relationship between respiration, nitrogen and phosphorus excretion and specific activity of amylase and trypsin was investigated from shipboard experiments with several species of copepods from the equatorial divergence area of the Indian Ocean, in June 1978. Statistical analysis of O:N ratios in 6 of the most common species revealed three main groups: a group displaying low O:N (Pontella fera, Candacia pachydactyla); a group with high O:N (Undinula darwini, Euchaeta marina, Temora discaudata); and a species displaying an intermediate O:N ratio: Scolecithrix bradyi. O:P and N:P did not differ significantly between species. There was a direct relationship between average O:N and the ratios of specific activity of the digestive enzymes amylase and trypsin. Species displaying low O:N and/or A:T ratios such as P. fera, C. pachydactyla and Oncaea venusta probably metabolize proteins more efficiently than they do plant carbohydrates (high nitrogen excretion and low amylase activity). Species displaying high O:N and A:T ratios, such as U. darwini, E. marina and T. dicaudata (low nitrogen excretion and high amylase activity) were assumed to use carbohydrates (starch) and proteins with equal efficiency. S. bradyi showed a large range of variations in trypsin activity and low amylase activity, resulting in a low average A:T ratio, but its O:N ratio was intermediate. Variations in O:N and O:P ratios were related to differences in the nutritional strategy of the different species, based on literature data concerning the anatomy of their mouth parts and their selectivity for animal material in mixed-food experiments.

Kidney ageing and renal excretion of amylase.

In a cross-sectional study, the amylase to creatinine clearance ratio (ACCR) was determined in 180 patients, age range 18-93 years. An inverse correlation was found between ACCR and creatinine clearance (r = -0.40, p less than 0.001) in keeping with the known inverse relationship between the sieving fraction of macromolecules and the glomerular filtration rate. The fractional clearance of amylase was not significantly affected by amylasemia nor by age when the creatinine clearance was also considered in a multiple regression analysis. No increase in ACCR was observed in patients with low molecular weight proteinuria or with induced urine dilution. The authors assume that the tubular reabsorption of amylase is minimal and that the enhancement of ACCR in the elderly mainly reflects modifications in the glomerular filtration dynamics.