Effect of an Emulsified Formulation on Vegetable Carotenoid Bioaccessibility.

We investigated the effect of neutral lipids, polar lipids, and an emulsified formulation (EMF) on carotenoid bioaccessibility in an in vitro digestion assay of vegetables. These reagents enhanced carotenoid bioaccessibility. Contrary to our previous report, they also exhibited effects on lutein. Bile extracts/pancreatin concentrations also participated in the bioaccessibility. The EMF, which consisted of lower amounts of oil, had the same effect on lutein as rapeseed oil. These reagents also showed effects in the aging model, with more reduced bile extract/pancreatin concentrations, suggesting that lipids and EMF contributed to carotenoid bioaccessibility in bile/pancreatic juice secretions due to aging and disease.

Pathogenesis of pancreatic encephalopathy in severe acute pancreatitis.

BACKGROUND: Pancreatic encephalopathy (PE) is a serious complication of severe acute pancreatitis (SAP). In recent years, more and more PE cases have been reported worldwide, and the onset PE in the early stage was regarded as a poor prognosis sign of SAP, but the pathogenesis of PE in SAP still has not been clarified in the past decade. The purpose of this review is to elucidate the possible pathogenesis of PE in SAP. DATA SOURCES: The English-language literature concerning PE in this review came from the Database of MEDLINE (period of 1991-2005), and the keywords of severe acute pancreatitis and pancreatic encephalopathy were used in the searching. RESULTS: Many factors were involved in the pathogenesis of PE in SAP. Pancreatin activation, excessive release of cytokines and oxygen free radicals, microcirculation abnormalities of hemodynamic disturbance, ET-1/NO ratio, hypoxemia, bacterial infection, water and electrolyte imbalance, and vitamin B1 deficiency participated in the development of PE in SAP. CONCLUSIONS: The pathogenesis of PE in SAP has not yet been fully understood. The development of PE in SAP may be a multi-factor process. To find out the possible inducing factor is essential to the clinical management of PE in SAP.

Agonist-induced localized Ca2+ spikes directly triggering exocytotic secretion in exocrine pancreas.

We investigated how agonist-induced patterned rises in cytosolic Ca2+ concentration ([Ca2+]i) regulate exocytotic secretion in the rat pancreatic acinar cell. The distribution of [Ca2+]i was visualized with a confocal microscope, which revealed that a Ca2+ ionophore, A23187, induced slow and homogeneous [Ca2+]i rises, while acetylcholine (ACh) always triggered primary Ca2+ spikes at the granular area which bears secretory granules. Secretion was monitored by measuring capacitance with the patch clamp method. Errors in the estimates of membrane capacitance (C) due to changes in conductance (G) were experimentally as well as theoretically evaluated to be one-tenth of the actual signals. We found that A23187 raised G without changing C at a low concentration, while it triggered asynchronous rises in G and C with lags in C, at a high concentration. By contrast, ACh triggered simultaneous rapid rises in G and C. Our results support the hypothesis that exocytotic secretion is less sensitive to Ca2+ than to ion channels and is directly caused by agonist-induced primary Ca2+ spikes at the granular area. It is therefore suggested that spatio-temporal patterns of Ca2+ oscillations could play a key role in exocytotic secretion from the exocrine acinar cell.

Human postprandial gastric emptying of 1-3-millimeter spheres.

Microspheres of pancreatin should empty from the stomachs of patients with pancreatic insufficiency as fast as food. The present study was undertaken in 26 healthy subjects to identify the size of spheres that would empty from the stomach with food and to determine whether different meals alter this size. Spheres of predefined sizes were labeled with 113mIn or 99mTc. Using a gamma-camera, we studied the concurrent gastric emptying of spheres labeled with 113mIn and of chicken liver labeled with 99mTc in 100-g, 154-kcal or 420-g, 919-kcal meals, or the concurrent emptying of 1-mm vs. larger spheres. One-millimeter spheres emptied consistently (p less than 0.01, paired t-test) faster than 2.4- or 3.2-mm spheres when ingested together with either the 420- or 100-g meals. Thus, in the 1-3-mm range of diameters, sphere size was a more important determinant of sphere emptying than meal size. Statistical analyses indicated that spheres 1.4 +/- 0.3 mm in diameter with a density of 1 empty at the same rate as 99mTc-liver. Our data indicate some commercially marketed microspheres of pancreatin will empty too slowly to be effective in digestion of food.

Messenger role of calcium in function of pancreatic acinar cells.

Enzyme secretion from the exocrine pancreas is elicited by a) cholinergic stimulants, b) hormones belonging to the family of pancreozymin, c) some amphibian peptides such as bombesin, eledoisin, and physalaemin, and d) secretin and vasoactive intestinal polypeptide. Whereas the mechanism of the group d hormones in stimulating enzyme secretion involves adenosine 3',5'-cyclic monophosphate, the others seem to use a common pathway involving Ca2+ as intracellular messenger and probably guanosine 3',5'-cyclic monophosphate as modulator of their action. Their effects can be ascribed to two processes. One pathway involves release of Ca2+ from an intracellular store that is most likely located in the plasma membrane. This phase is independent of extracellular Ca2+ and leads to a rise of guanosine 3',5'-cyclic monophosphate. The other pathway is characterized by an increased permeability of the plasma membrane for Ca2+ and is necessary for sustained secretion. Both pathways lead to an increase cytosolic-free Ca2+ concentration. Ca2+ is either directly involved in fusion of zymogen granules with the luminal cell membrane or triggers events that lead to exocytosis. Furthermore, augmented cytosolic-free calcium concentration a) increased the plasma membrane permeability for Na+, Cl-, and K+, which leads to depolarization of the cell, and b) induces uncoupling of neighboring acinar cells.

The potential role of protein in the absorption of fat.

Stabilization of triglyceride emulsions by proteins was studied in vitro using either chemical or optical methods to measure to amount of fat emulsified under standard conditions of emulsification. Concentrations, pH, and degree of digestion of protein emulsifiers were varied to determine how such manipulations affected emulsion stabilization. Proteins from endogenous as well as exogenous sources were capable of stabilizing triglyceride emulsions, and this effect varied with protein concentration. Peptic digests of a prototype protein retained the efficacy of the undigested protein, while further digestion of the protein in pancreatic proteases decreased, but did not abolish, the emulsifying power of the protein. Emulsion stabilization by peptic digests of protein still persisted despite alterations in pH from 1 to 7. Such emulsions were capable of being hydrolyzed by pancreatic lipase and could be absorbed from the gut of bile-deficient rats. These emulsions also speed the initial rates of fat absorption from animals with an intact bile supply. We conclude that stabilization of luminal emulsions by dietary or endogenous protein may facilitate fat absorption similar to the way that detergent-stabilized emulsions have been previously shown to have these effects.