Pancreatic Serine Proteases Research Articles

Marked difference in efficiency of the digestive enzymes pepsin, trypsin, chymotrypsin, and pancreatic elastase to cleave tightly folded proteins.

In order for the intestinal mucosa to absorb dietary proteins they have to be digested into single amino acids or very short peptides of a length of not more than four amino acids. In order to study the efficiency of the digestive endopeptidases to digest folded proteins we have analyzed several target proteins under different conditions, native proteins, heat denatured and acid treated. The three pancreatic serine proteases, trypsin, chymotrypsin, and pancreatic elastase, were found to be remarkable inefficient in cleaving native folded proteins whereas pepsin, which acts at a very low pH (pH1.2) was much more efficient, possibly due to the denaturing conditions and thereby better accessibility to internal cleavage sites at the low pH. Heat treatment improved the cleavage considerably by all three pancreatic enzymes, but acid treatment followed by return to neutral pH did not have any major effect. Cleavage at the low pH when the protein is in a denatured state, is apparently very efficient. This indicates that pepsin is the prime enzyme cleaving the properly folded native proteins and that the pancreatic enzymes primarily are involved in generating single amino acids or very short peptides for efficient uptake by the intestinal mucosa.

DEVELOPMENT AND VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR DETERMINATION OF BROMELAIN, TRYPSIN, RUTOSIDE AND DICLOFENAC IN BULK AND PHARMACEUTICAL DOSAGE FORM

Serine proteases are enzymes that cleave peptide bond in proteins in which serine serves as the nucleophilic amino acid at the active site. Tripsin is apancreatic serine protease with substrate specifically based upon positively charged lysine and arginine side chains. The selected dosage form trypsin, rutoside, bromelain contains natural pancreatic serine protease used to treat pain and inflammatory diseases. The objective of present research work is to develop a novel, simple, accurate and precise reversed phase High Performance Liquid Chromatography (HPLC) stability indicating method for rapid and simultaneous quantification of Bromelain, Trypsin, Rutoside and Diclofenac. Since this is a new combination of pharmaceutical dosage form and no HPLC methods were developed .There is a need to develop a chromatographic method which is cost effective. This chromatographic method is developed which can easily analyze mixture of compounds with less retention time and low solvent consumption. The chromatographic separation was achieved on Inertsil ODS (250x4.6mm, 5µ). Mobile phase contained a mixture of OPA buffer at pH 2.4 and Acetonitrile in the ratio of 50:50 v/v, flow rate 1.0 ml/min and UV detection at 257nm. The proposed method shows a good linearity in the concentration range of 22.5-135 µg/ml for Bromelain, 12-72µg/ml of Trypsin, 25-150µg/ml of Rutoside and 12.5-75 µg/ml for Diclofenac under optimised conditions. Precision and recovery study results are in between 98-102%. In the entire robustness conditions %RSD is below 2.0%. Degradation has minimum effect in stress condition and solutions are stable up to 24 hrs. This method is validated for different parameters. The study was determined according to the ICH Q2B guidelines. All the parameters of validation were found to be within the acceptance range of ICH guidelines. The developed chromatographic method can be used in routine analysis in pharmaceutical industry.

Overlapping Specificity of Duplicated Human Pancreatic Elastase 3 Isoforms and Archetypal Porcine Elastase 1 Provides Clues to Evolution of Digestive Enzymes

Chymotrypsin-like elastases (CELAs) are pancreatic serine proteinases that digest dietary proteins. CELAs are typically expressed in multiple isoforms that can vary among different species. The human pancreas does not express CELA1 but secretes two CELA3 isoforms, CELA3A and CELA3B. The reasons for the CELA3 duplication and the substrate preferences of the duplicated isoforms are unclear. Here, we tested whether CELA3A and CELA3B evolved unique substrate specificities to compensate for the loss of CELA1. We constructed a phage library displaying variants of the substrate-like Schistocerca gregaria proteinase inhibitor 2 (SGPI-2) to select reversible high affinity inhibitors of human CELA3A, CELA3B, and porcine CELA1. Based on the reactive loop sequences of the phage display-selected inhibitors, we recombinantly expressed and purified 12 SGPI-2 variants and determined their binding affinities. We found that the primary specificity of CELA3A, CELA3B, and CELA1 was similar; all preferred aliphatic side chains at the so-called P1 position, the amino acid residue located directly N-terminal to the scissile peptide bond. P1 Met was an interesting exception that was preferred by CELA1 but weakly recognized by the CELA3 isoforms. The extended substrate specificity of CELA3A and CELA3B was comparable, whereas CELA1 exhibited unique interactions at several subsites. These observations indicated that the CELA1 and CELA3 paralogs have some different but also overlapping specificities and that the duplicated CELA3A and CELA3B isoforms did not evolve distinct substrate preferences. Thus, increased gene dosage rather than specificity divergence of the CELA3 isoforms may compensate for the loss of CELA1 digestive activity in the human pancreas.

Adsorption isotherms, kinetics and thermodynamic studies towards understanding the interaction between cross-linked alginate-guar gum matrix and chymotrypsin.

The adsorption kinetics of chymotrypsin, a pancreatic serine protease, onto an alginate-gum guar matrix cross-linked with epichlorohydrin has been performed using a batch-adsorption technique. The effect of various experimental parameters such as pH, salt presence, contact time and temperature were investigated. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data which shows that the adsorption of the enzyme followed the pseudo-second-order rate expression. The Langmuir, Freundlich and Hill adsorption isotherm models were applied to describe the equilibrium isotherms, and the isotherm constants were determined. It was found that Hill model was more suitable for our data because the isotherm data showed a sigmoidal behavior with the free enzyme concentration increasing in equilibrium. At 8°C and at pH 5.0, 1g hydrate matrix adsorbed about 7mg of chymotrypsin. In the desorption process 80% of the biological activity of chymotrypsin was recovered under the condition of 50mM phosphate buffer, pH 7.00-500mM NaCl. When successive cycles of adsorption/washing/desorption were performed, it was observed that the matrix remained functional until the fourth cycle of repeated batch enzyme adsorption. These results are important in terms of diminishing of cost and waste generation.

Mesotrypsin Signature Mutation in a Chymotrypsin C (CTRC) Variant Associated with Chronic Pancreatitis

Human chymotrypsin C (CTRC) protects against pancreatitis by degrading trypsinogen and thereby curtailing harmful intra-pancreatic trypsinogen activation. Loss-of-function mutations in CTRC increase the risk for chronic pancreatitis. Here we describe functional analysis of eight previously uncharacterized natural CTRC variants tested for potential defects in secretion, proteolytic stability, and catalytic activity. We found that all variants were secreted from transfected cells normally, and none suffered proteolytic degradation by trypsin. Five variants had normal enzymatic activity, whereas variant p.R29Q was catalytically inactive due to loss of activation by trypsin and variant p.S239C exhibited impaired activity possibly caused by disulfide mispairing. Surprisingly, variant p.G214R had increased activity on a small chromogenic peptide substrate but was markedly defective in cleaving bovine β-casein or the natural CTRC substrates human cationic trypsinogen and procarboxypeptidase A1. Mutation p.G214R is analogous to the evolutionary mutation in human mesotrypsin, which rendered this trypsin isoform resistant to proteinaceous inhibitors and conferred its ability to cleave these inhibitors. Similarly to the mesotrypsin phenotype, CTRC variant p.G214R was inhibited poorly by eglin C, ecotin, or a CTRC-specific variant of SGPI-2, and it readily cleaved the reactive-site peptide bonds in eglin C and ecotin. We conclude that CTRC variants p.R29Q, p.G214R, and p.S239C are risk factors for chronic pancreatitis. Furthermore, the mesotrypsin-like CTRC variant highlights how the same natural mutation in homologous pancreatic serine proteases can evolve a new physiological role or lead to pathology, determined by the biological context of protease function.

Changes in extra- and intracellular pH in hepatocytes exposed to gabexate mesilate.

Gabexate mesilate (GM) is a synthetic inhibitor of plasmatic and pancreatic serine proteases licensed for the treatment of pancreatitis. Here we show that in suspensions of isolated hepatocytes, profound changes in extracellular, cytoplasmic, and vesicular pH occur after addition of GM. Isolated hepatocytes obtained by collagenase perfusion of rat liver were pre-incubated with 1, 2, and 4 mM GM. Extracellular pH (pH in the incubation medium) was measured by a conventional pH electrode, cytosolic and vesicular pH were measured by fluorescence changes of 2',7'-biscarboxyethyl-5,6-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and fluorescein dextran, respectively. Incubation of hepatocytes with GM resulted in a dose-dependent decrease of extracellular pH. Cytosolic pH decreased rapidly and markedly in a dose-dependent manner during the first minutes and gradually returned towards baseline. Simultaneously, GM induced a rapid alkalinization of acidic vesicles. The presence of bis-(p-nitrophelyl) phosphate (BNPP), an esterase inhibitor, reduced the extent of extracellular acidification. Incubation of hepatocytes in the presence of dimethylamiloride, an Na+/H+ exchanger inhibitor, or in a sodium-free medium, did not modify the rate and extent of extracellular acidification. GM, a commercially available pharmacological agent, could be useful to manipulate extra- and intracellular pH.

Obtainment of a highly concentrated pancreatic serine proteases extract from bovine pancreas by precipitation with polyacrylate

Serine proteases have wide application in leather, food, meat and soap powder industries, among others. There are a lot of methodologies to obtain them in large quantities but most of them are expensive or contaminating. We then propose an economical and environmentally friendly method in which proteases are separated from a crude fresh bovine pancreas homogenate using precipitation with polyacrylate, a commercially available negatively charged and weak polyelectrolyte. The zymogens of the serine proteases were activated prior to precipitation by the addition of trypsin. The proteases were precipitated by adding polyacrylate at pH 4.50 to the pancreas homogenate. Under these conditions, serine proteases are positively charged and form non-soluble complexes with the negatively charged polyacrylate. The purity of proteases was increased 5-fold with a recovery of 33% under the best conditions tested. The volume of the final product was decreased to 5% of the feedstock, in order to concentrate the sample up to 20times. The proposed method removed up to 96% of the contaminant proteins.

Long-range Electrostatic Complementarity Governs Substrate Recognition by Human Chymotrypsin C, a Key Regulator of Digestive Enzyme Activation

Human chymotrypsin C (CTRC) is a pancreatic serine protease that regulates activation and degradation of trypsinogens and procarboxypeptidases by targeting specific cleavage sites within their zymogen precursors. In cleaving these regulatory sites, which are characterized by multiple flanking acidic residues, CTRC shows substrate specificity that is distinct from that of other isoforms of chymotrypsin and elastase. Here, we report the first crystal structure of active CTRC, determined at 1.9-Å resolution, revealing the structural basis for binding specificity. The structure shows human CTRC bound to the small protein protease inhibitor eglin c, which binds in a substrate-like manner filling the S6-S5' subsites of the substrate binding cleft. Significant binding affinity derives from burial of preferred hydrophobic residues at the P1, P4, and P2' positions of CTRC, although acidic P2' residues can also be accommodated by formation of an interfacial salt bridge. Acidic residues may also be specifically accommodated in the P6 position. The most unique structural feature of CTRC is a ring of intense positive electrostatic surface potential surrounding the primarily hydrophobic substrate binding site. Our results indicate that long-range electrostatic attraction toward substrates of concentrated negative charge governs substrate discrimination, which explains CTRC selectivity in regulating active digestive enzyme levels.

Determinants of chymotrypsinC cleavage specificity in the calcium-binding loop of human cationic trypsinogen.

The pancreatic serine protease chymotrypsin C (CTRC) cleaves the Leu81-Glu82 peptide bond in the calcium-binding loop of human cationic trypsinogen and thereby promotes its degradation. This serves as a protective mechanism against ectopic trypsinogen activation in the pancreas. In the present study, we demonstrate that cleavage of the Leu81-Glu82 peptide bond by CTRC is highly specific, and other human pancreatic chymotrypsins (CTRB1, CTRB2 and CTRL1) and elastases (ELA2A, ELA3A and ELA3B) do not catalyze this reaction. To elucidate the mechanistic basis for CTRC specificity, we surveyed the primary (P1) cleavage preference of these pancreatic proteases on peptide substrates. We found that CTRC cleaved after a P1 Leu with at least tenfold higher catalytic efficiency than other enzymes tested. To assess extended sub-site interactions, we introduced Ala mutations into human cationic trypsinogen at the P3, P1' P3' and P4' amino acid positions, where P1-P1' corresponds to Leu81-Glu82. Interestingly, CTRC-mediated cleavage was stimulated threefold by mutation E82A and unaffected by mutations E79A and N84A, but all three mutations compromised specificity and resulted in increased cleavage by ELA2A. Mutation E85A decreased CTRC cleavage by twofold. Remarkably, other chymotrypsins and elastases did not cleave human cationic trypsinogen even with the L81F or L81A mutations, which introduced favorable P1 residues for these enzymes. We conclude that specific cleavage of the Leu81-Glu82 peptide bond in human cationic trypsinogen by CTRC is primarily determined by its distinctively high activity on leucyl peptide bonds, with the P1' Glu82, P3' Asn84 and P4' Glu85 residues serving as additional specificity determinants.

Adsorption and hydrolytic activity of trypsin on a carboxylate-functionalized cation exchanger prepared from nanocellulose

Immobilization of enzymes on polymer supports has been considered as a powerful technique in biomedical applications. In this study, a cellulose-based hydrogel, poly(acrylic acid)-modified poly(glycidylmethacrylate)-grafted nanocellulose (PAPGNC) was synthesized by graft copolymerization technique and well characterized. A pancreatic serine protease trypsin (TRY) was immobilized onto PAPGNC, under different optimized conditions. The optimum pH for TRY adsorption was found to be 6.5, and the adsorption attained equilibrium within 90min. The kinetic data were found to follow pseudo-first-order model, which is based on solid capacity. The well agreement of equilibrium data with Langmuir isotherm model confirms the monolayer coverage of TRY onto PAPGNC surface, and the maximum adsorption capacity was found to be 140.65mg/g at 30°C. The temperature dependence indicates an endothermic process. The relative activity of immobilized TRY in the hydrolysis of casein was higher than that of the free enzyme over broader temperature ranges. The immobilized TRY had high temperature and long-storage stability as compared to free TRY. Spent adsorbent was effectively degenerated using 0.1M KSCN with the retention in catalytic activity of 87% even after four cycles. The present investigation shows that PAPGNC is a valuable polymer support for the recovery of TRY from aqueous solutions and subsequent casein hydrolysis.

Pancreatic serine protease extraction by affinity partition using a free triazine dye

Affinity partitioning combines the partitioning behavior of biological macromolecules in aqueous two-phase systems with the principle of biorecognition. Among the numerous substances that have been evaluated as ligands, the reactive dyes constitute a group of low cost textile dyes which have proved to act as biomimetic ligands for many enzymes. The ability of reactive yellow 2 (RY2) to interact with trypsin (TRP) and chymotrypsin (ChTRP) and its behavior in aqueous two-phase systems formed by polyethylene glycol (PEG) and sodium citrate (NaCit) – were investigated. Different variables such as PEG molecular weight, tie line length and dye concentration were analyzed. RY2 showed to bind specifically to both TRP and ChTRP with affinity constants near to 103M−1. Its partition equilibrium is practically displaced to the top phase in systems formed by PEG of different molecular weight. Addition of this dye to PEG 8000/NaCit systems until a final concentration of 0.196% (w/w) induced an increase in TRP and ChTRP partition coefficients of at least 2 times over that in the absence of the ligand. These findings demonstrate that RY2 fulfils all the requirements to be considered as an affinity ligand in aqueous two-phase partitioning of TRP and ChTRP.

Impact of host proteases on reovirus infection in the respiratory tract.

Virion uncoating is an essential early event in reovirus infection. In natural enteric infections, rapid proteolytic uncoating of virions is mediated by pancreatic serine proteases. The proteases that promote reovirus disassembly and cell entry in the respiratory tract remain unknown. In this report, we show that endogenous respiratory and inflammatory proteases can promote reovirus infection in vitro and that preexisting inflammation augments in vivo infection in the murine respiratory tract.

A Fermented Infant Milk Formula Reduces Ileal Proteolytic Activity

Background and aims: Gastrointestinal (GI) proteases are best known for their function in protein digestion. However, GI luminal serine protease activity is also associated with inflammation, pain and visceral hypersensitivity via activation of protease-activated receptor-2 (PAR-2). An infant milk formula comprising product fermented by Streptococcus thermophilus 065 and Bifidobacterium breve C50 has previously been reported to improve gut comfort in infants with digestive problems. Here, the effect of this fermented formula (Lactofidus) on proteolytic activity was investigated at the terminal ileum. Methods: The fermented formula and a non-fermented standard formula were tested in three-week-old piglets (N=6) fitted with a T-cannula. Each formula was provided in a Latin square design. Ileal digesta were collected during eight hours and subsequently analyzed for total proteolytic activity and protein digestibility. Proteolytic activity was further characterized either by specific substrates or inhibitors as serine protease, trypsin, or chymotrypsin activity. Results: Fermented formula yielded a more than threefold lower total proteolytic activity at the terminal ileum compared to standard formula (477 ± 84 ·103 and 1599 ± 343 ·103 units/8h, respectively). This proteolytic activity was found to be mainly constituted by the pancreatic serine proteases trypsin and chymotrypsin. Despite lower proteolytic activity in the fermented formula, protein was fully digested. Conclusions: The fermented formula causes lower exposure of the small intestine to pancreatic serine proteases. This could contribute to improved gut comfort via diminished activation of PAR-2, which could be particularly beneficial in infants with digestive problems.

Escherichia coli EHEC Germany outbreak preliminary functional annotation using BG7 system

We have annotated the European outbreak E. coli EHEC genome sequenced by BGI (6-2-2011) and assembled with MIRA by Nick Loman (6-2-2011 ). Our system BG7, Bacterial Genome annotation of Era7 Bioinformatics, predicts ORFs and annotates them based on fragments of similarity with Uniprot proteins. We have predicted 6327 genes, 6156 encoding proteins y 171 corresponding to ribosomal and tRNA. Based on the preliminary results of our semi-automated method of annotation we have selected some predicted proteins with potential implications in pathogenicity and virulence.There are 33 predicted genes annotated as toxins and we have found three putative hemolysins: Hemolysin E, a putative hemolysin expression modulating protein and a channel protein, hemolysin III family. We have found 31 predicted genes that could be related to specific antibiotic resistance: beta-lactamic, aminoglycoside, macrolide, polymyxin, tetracycline, fosfomycin and deoxycholate, novobiocin, chloramphenicol, bicyclomycin, norfloxacin and enoxacin and 6-mercaptopurine. This strain is rich in adhesion, secretion systems, pathogenicity and virulence related proteins. It seems to have a restriction-modification system, many proteins involved in Fe transport and utilization (siderophores as aerobactin and enterobactin), lysozyme, one inhibitor of pancreatic serine proteases, proteins involved in anaerobic respiration, antimicrobial peptides, and proteins involved in quorum sensing and biofilm formation that could confer competitive advantage to this strain.

Escherichia coli EHEC Germany outbreak preliminary functional annotation using BG7 system

AbstractWe have annotated the European outbreak E. coli EHEC genome sequenced by BGI (6-2-2011) and assembled with MIRA by Nick Loman (6-2-2011 ). Our system BG7, Bacterial Genome annotation of Era7 Bioinformatics, predicts ORFs and annotates them based on fragments of similarity with Uniprot proteins. We have predicted 6327 genes, 6156 encoding proteins y 171 corresponding to ribosomal and tRNA. Based on the preliminary results of our semi-automated method of annotation we have selected some predicted proteins with potential implications in pathogenicity and virulence.There are 33 predicted genes annotated as toxins and we have found three putative hemolysins: Hemolysin E, a putative hemolysin expression modulating protein and a channel protein, hemolysin III family. We have found 31 predicted genes that could be related to specific antibiotic resistance: beta-lactamic, aminoglycoside, macrolide, polymyxin, tetracycline, fosfomycin and deoxycholate, novobiocin, chloramphenicol, bicyclomycin, norfloxacin and enoxacin and 6-mercaptopurine. This strain is rich in adhesion, secretion systems, pathogenicity and virulence related proteins. It seems to have a restriction-modification system, many proteins involved in Fe transport and utilization (siderophores as aerobactin and enterobactin), lysozyme, one inhibitor of pancreatic serine proteases, proteins involved in anaerobic respiration, antimicrobial peptides, and proteins involved in quorum sensing and biofilm formation that could confer competitive advantage to this strain.

Differential Effects of Serine Proteases on the Migration of Normal and Tumor Cells: Implications for Tumor Microenvironment

The supporting role of proteases in tumor progression and invasion is well known; however, the use of proteases as therapeutic agents has also been demonstrated. In this article, the authors report on the differential effects of exogenous serine proteases on the motility of tumor and normal cells. The treatment of normal and tumor cells with a single dose of pancreatic serine proteases, trypsin (TR) and chymotrypsin (CH), leads to a concentration-dependent response by cells, first accelerating and then slowing mobility. Tumor cells are 10 to 20 times more sensitive to exogenous TR/CH, suggesting that a single dose of proteases may cause discordant movements of normal and tumor cells within the tumor environment. The inhibitory effects of TR on cell motility are contradicted by thrombin (TH), particularly in the regulation of normal cells' migration. The purpose of this investigation was to ascertain the role of protease-activated receptors (PARs) in terms of normal and tumor cell motility. Duplicate treatments with proteases resulted in diminished mobility of both normal and tumor cells. Repeated application of TR and TH in 1-hour treatment intervals initially desensitizes cell surface PARs. However, cell surface PARs reappear regardless of subsequent protease treatments in both normal and tumor cells. The resensitization process is retarded in tumor cells when compared with normal cells. This is evidenced by lower expression of PARs as well as by their relocalization at the tumor cell surfaces. Under these conditions, normal cells remain responsive to exogenous proteases in terms of cell motility. Exogenous proteases do not modulate motility of repeatedly stimulated tumor cells, and consequently, the migration of tumor cells appears disconnected from the PAR signaling pathways. The use of activating peptides in lieu of the cognate proteases for a given PAR system indicated that proteases may act through additional targets not regulated by PAR signaling. We hypothesize that the divergent migration patterns of normal and tumor cells due to exposure to proteases is in part mediated by PARs. Thus, treatment with exogenous proteases may cause rearrangement of the tumor and stromal cells within the tumor microenvironment. Such topographical effects may lead to the inhibition of tumor progression and metastasis development.

Kinetic characterization of hydrolysis of camel and bovine milk proteins by pancreatic enzymes

As differences in protein composition between camel and bovine milk may influence their digestibility, hydrolysis of milk proteins of both species using two pancreatic serine proteases (trypsin and chymotrypsin) was studied. Caseins (CNs) were more rapidly hydrolyzed than whey proteins (WPs) because of their greater flexibility and open structures. The extent of hydrolysis by chymotrypsin of CNs in both species was significantly higher than that of hydrolysis by trypsin, which is due mainly to the greater number of potential hydrolytic sites present in the primary structures of CNs targeted by chymotrypsin than by trypsin. The extent of hydrolysis of camel WPs by each protease separately or by their mixture was less than that of bovine WPs, which can be explained by the greater stability of camel WPs compared with that of bovine WPs. The kinetic parameters ( K m and k cat) widely varied for different substrates, which results from differences in binding affinities and substrate turnovers, respectively.

The Crystal Structure of a Trypsin-like Mutant Chymotrypsin: The Role of Position 226 in the Activity and Specificity of S189D Chymotrypsin

The crystal structure of the S189D+A226G rat chymotrypsin-B mutant has been determined at 2.2 angstroms resolution. This mutant is the most trypsin-like mutant so far in the line of chymotrypsin-to-trypsin conversions, aiming for a more complete understanding of the structural basis of substrate specificity in pancreatic serine proteases. A226G caused significant rearrangements relative to S189D chymotrypsin, allowing an internal conformation of Asp189 which is close to that in trypsin. Serious distortions remain, however, in the activation domain, including zymogen-like features. The pH-profile of activity suggests that the conformation of the S1-site of the mutant is influenced also by the P1 residue of the substrate.

Development of a peptide-containing chewing gum as a sustained release antiplaque antimicrobial delivery system.

The objective of this study was to characterize the stability of KSL-W, an antimicrobial decapeptide shown to inhibit the growth of oral bacterial strains associated with caries development and plaque formation, and its potential as an antiplaque agent in a chewing gum formulation. KSL-W formulations with or without the commercial antibacterial agent cetylpyridinium chloride (CPC) were prepared. The release of KSL-W from the gums was assessed in vitro using a chewing gum apparatus and in vivo by a chew-out method. A reverse-phase high-performance liquid chromatography method was developed for assaying KSL-W. Raw material stability and temperature and pH effects on the stability of KSL-W solutions and interactions of KSL-W with tooth-like material, hydroxyapatite discs, were investigated. KSL-W was most stable in acidic aqueous solutions and underwent rapid hydrolysis in base. It was stable to enzymatic degradation in human saliva for 1 hour but was degraded by pancreatic serine proteases. KSL-W readily adsorbed to hydroxyapatite, suggesting that it will also adsorb to the teeth when delivered to the oral cavity. The inclusion of CPC caused a large increase in the rate and extent of KSL-W released from the gums. The gum formulations displayed promising in vitro/in vivo release profiles, wherein as much as 90% of the KSL-W was released in a sustained manner within 30 minutes in vivo. These results suggest that KSL-W possesses the stability, adsorption, and release characteristics necessary for local delivery to the oral cavity in a chewing gum formulation, thereby serving as a novel antiplaque agent.

Recurrent idiopathic pancreatitis in familial adenomatous polyposis: Report of a case-series and review of the literature

Familial adenomatous polyposis (FAP) is characterized by the development of multiple adenomatous polyps predominantly in the colon but also in the duodenum. Scattered case reports indicate that there is a risk for pancreatitis in FAP. The most likely cause of pancreatitis in FAP is obstructing ampullary adenomas. We describe 7 FAP patients who experienced one or more episodes of pancreatitis. Two patients experienced pancreatitis after endoscopic treatment of ampullary adenoma. The cause of the pancreatitis in 5 of 7 patients could not be determined, as none of the patients had obstruction of the ampulla. Furthermore, other risk factors for pancreatitis such as pancreatic serine protease inhibitor Kazal type I (SPINK1) gene mutations were ruled out. A review of literature identified 20 FAP patients who developed the first episode of pancreatitis at a mean age of 45 years (range 23-72 years). Some 55% had recurrent episodes of pancreatitis. Eight patients had (peri) ampullary adenomas or carcinomas. In most cases, the course of pancreatitis was mild with an uneventful outcome, but one patient died after an episode of acute pancreatitis.