Pepsin Concentration Research Articles

Chemical and biophysical properties of gelatins extracted from the skin of octopus (Octopus vulgaris)

Gelatins from alkali-pre-treated skin of Octopus (Octopus vulgaris) were extracted with different concentrations of pepsin at pH 2.0. The resulting octopus skin gelatins OSG0, OSG5, OSG10 and OSG15, extracted, respectively, without enzyme treatment or with 5, 10 and 15 U of pepsin/g alkaline treated skin were evaluated for gel strength, textural parameters, thermal and gelling properties. The yield of gelatin extracted without enzymatic pretreatment was only 3.21% and the addition of pepsin (15 U/g) increased the yield of gelatin extraction to 7.78%. Molecular weight distribution of gelatins indicates that OSG10 and OSG15 contain peptides with molecular weights less than 10 kDa (>40%). In addition, Fourier transform infrared (FTIR) spectra of extracted gelatins were slightly different, indicating that the triple helical structure of gelatins was affected by pepsin treatment. Compared to OSG0, pepsin gelatins exhibited lower gel strength, hardness, adhesiveness, transition, gelling and melting temperatures and all of the values decreased with increasing enzyme concentration. In addition foam expansion (FE) was affected by enzyme treatment, and the values decreased as pepsin increased. However, the emulsifying activity index (EAI) values of all gelatins were the same. Further, FE and EAI increased with increasing concentrations (1–3%, w/v). The results showed that octopus skin can be a good source for gelatin.

Exhaled Breath Condensate Pepsin: Potential Noninvasive Test for Gastroesophageal Reflux in COPD and Bronchiectasis.

Acid gastroesophageal reflux is a common problem in non-cystic fibrosis bronchiectasis and COPD. Invasive methods are used to diagnose gastroesophageal reflux, but the ability to detect pulmonary microaspiration of gastric contents using this method is unclear. A noninvasive option to detect pulmonary microaspiration is to measure pepsin in exhaled breath condensate (EBC), but this has not been related to esophageal pH monitoring in these lung conditions. This study aimed to measure pepsin concentrations and pH in EBC and to determine the relationship to gastroesophageal reflux in bronchiectasis or COPD. Subjects with bronchiectasis (n=10) or COPD (n=10) and control subjects (n=10) completed 24-h esophageal pH monitoring for detection of acid gastroesophageal reflux, measuring the percentage of reflux time in the proximal esophagus and the DeMeester score (DMS). Concurrently, 3 samples of EBC were collected from each subject, and pH was measured and pepsin concentrations were analyzed by enzyme-linked immunosorbent assay. EBC pepsin was detected in subjects with bronchiectasis (44%) or COPD (56%) and in control subjects (10%). A diagnosis of gastroesophageal reflux was not associated with a higher concentration of EBC pepsin in bronchiectasis (P=.21) or COPD (P=.11). EBC pepsin concentration did not correlate with DMS (rs=0.36) or proximal reflux index (rs=0.25) in subjects with bronchiectasis or with DMS (rs=0.28) or proximal reflux index (rs=0.21) in patients with COPD. EBC and sputum pepsin concentrations were moderately correlated in bronchiectasis (rs=0.56) and in COPD (rs=0.43). Pepsin is detectable in EBC samples in bronchiectasis and COPD. Although no association was found between pepsin concentrations and a diagnosis of gastroesophageal reflux, a moderate relationship between sputum and EBC pepsin concentrations suggests that EBC pepsin may be a useful noninvasive marker of pulmonary microaspiration.

Pepsin deteriorates prognosis of children with otitis media with effusion who undergo myringotomy or tympanostomy tube insertion

ObjectiveTo investigate the concentrations of pepsin and pepsinogen within the middle ear cavity and determine whether pepsin and pepsinogen affect the prognosis of children with otitis media with effusion (OME). MethodsAll middle-ear lavage fluid from patients with OME undergoing myringotomy (M subgroup) or tympanostomy tube insertion (T subgroup) was collected and pepsin and pepsinogen were detected using enzyme-linked immunosorbent assay. After close follow-up over 2 years, the effects of pepsin and pepsinogen on the prognosis of the patients with OME in the M and T subgroups were analyzed. ResultsThe average pepsin and pepsinogen concentrations were significantly lower in the M subgroup (n=54; 24.38±16.10mg/mL and 286.49±91.95mg/mL, respectively) than in the T subgroup (n=55; 45.56±16.60mg/mL and 664.92±107.06mg/mL; t=2.484, P=0.018 and t=2.670, P=0.011, respectively). In the M subgroup, the average time to tympanic membrane healing and tympanic pressure restoration to normal was much longer in pepsin(+) patients (17.0±2.0 days and 26.0±2.5 days, respectively) than in pepsin(−) patients (14.0±1.1 days and 22.0±1.0 days; t=3.871, P=0.001 and t=5.734, P=0.000, respectively), and the hearing level of pepsin(+) patients with OME ascended to 13.08±1.19dB, which was much lower than that of pepsin(−) patients (18.29±1.27dB; t=11.001, P=0.000). In the T subgroup, the complication rate including otorrhea and myringosclerosis was much higher in patients with high pepsin concentrations than in those with low pepsin concentrations (P<0.05). Finally, in both subgroups, the recurrence rates of OME in pepsin(+) or patients with high pepsin concentrations (34.6% [9/26] and 28.6% [10/35]) were significantly higher than those in pepsin(−) or low pepsin concentrations (10.7% [3/28] and 5.0% [1/20]; χ2=4.456, P=0.035 and χ2=4.420, P=0.036). However, pepsinogen had no significant effect on OME prognosis or recurrence. ConclusionPepsin but not pepsinogen could postpone tympanic membrane healing and pressure restoration in children with OME undergoing myringotomy and increase the incidence of recurrence and complications including otorrhea and myringosclerosis for those undergoing tympanostomy tube insertion. Therefore, pepsin could be considered a poor prognostic factor for OME, further emphasizing the important role of pepsin in OME pathogenesis.

Modelling of pepsin digestibility of myofibrillar proteins and of variations due to heating

Digestibility of myofibrillar proteins by pepsin was determined by in vitro trials and mathematical modelling. A primary model was developed to predict in vitro digestion kinetics, and a secondary model based on the mechanisms of protein denaturation was then added to take into account the effect of meat heating. Model predictions agreed with measurements in the pH and pepsin concentration ranges 1.8–3.8 and 6–50Umg−1 respectively. The utility of the model is illustrated by a simple example where meat is assumed to be heated homogeneously, and myofibrillar proteins to be directly in contact with pepsin. The combined effects of heating time, temperature, enzyme concentration and pH modified the digestibility value, which also depends on residence time in the stomach.

The Influences of Pepsin Concentrations and pH Levels on the Disinfective Activity of Ozone Nanobubble Water against Helicobacter pylori

Aims: To investigate the utility of ozone nanobubble water (NBW3) for the treatment of Helicobacter pylori in the stomach, we tested the influence of pepsin concentrations and pH levels on the disinfective activity of NBW3, and the cytotoxicity of NBW3 against mammalian cells and mucosa. Methods: Different concentrations of pepsin were dissolved in NBW3, and the bactericidal activity was tested on H. pylori. NBW3 was adjusted to different pH levels (2.0-7.4) and the bactericidal activity on H. pylori was also tested. To examine the cytotoxicity of NBW3, AGS cells, human gastric epithelial cells, were treated with NBW3 and the viability of the cells was evaluated in vitro. Furthermore, NBW3 was administered to mice and gastric mucosal damage was evaluated by histology. Results: Pepsin reduced the disinfective activity of NBW3 on H. pylori in a pepsin concentration-dependent manner. NBW3 showed stable disinfective activity at all pH levels examined. Cytotoxicity of NBW3 against human gastric epithelial cells and gastric mucosa was not observed in our experimental setting. Conclusions: NBW3 can sustain its disinfective activity in wide range of pH levels and show no cytotoxicity on mammalian cells and tissue. Pepsin can inhibit NBW3 activity in a dose-dependent manner.

PTU-152 Pepsin In Saliva For The Diagnosis Of Gastro-esophageal Reflux Disease

IntroductionCurrent diagnostic tests for GORD have moderate sensitivity/specificity and can be invasive and expensive. Pepsin detection in saliva has been proposed as an “office-based” method for GORD diagnosis. The aims...

Pepsin in saliva for the diagnosis of gastro-oesophageal reflux disease

ObjectiveCurrent diagnostic methods for gastro-oesophageal reflux disease (GORD) have moderate sensitivity/specificity and can be invasive and expensive. Pepsin detection in saliva has been proposed as an ‘office-based’ method for GORD...

LRP1-dependent pepsin clearance induced by 2′-hydroxycinnamaldehyde attenuates breast cancer cell invasion

2′-Hydroxycinnamaldehyde inhibits breast cancer cell invasion. This study examined whether 2′-hydroxycinnamaldehyde, acting as a Michael acceptor, interferes with the ligand binding of low-density lipoprotein receptor-related protein 1 to mediate breast cancer cell invasion. Low-density lipoprotein receptor-related protein 1, one of the direct molecular targets of 2′-hydroxycinnamaldehyde, is a multifunctional endocytic receptor. Changes in the thiol oxidation status of cell surface receptor proteins may function as a molecular switch, influencing ligand(s) binding. The oxidation status of extracellular cysteine thiol groups in MCF-7 and MDA-MB-231 cells was examined using a fluorescence-activated cell sorter with thiol-specific fluorescent probes; Matrigel invasion and wound-healing assays were performed to determine the effects of 2′-hydroxycinnamaldehyde on in vitro cell migration. The molecular mechanisms by which 2′-hydroxycinnamaldehyde acts were evaluated by transient knockdown using siRNA or inhibition of low-density lipoprotein receptor-related protein 1 by receptor-associated protein treatment. 2′-Hydroxycinnamaldehyde increased α-2-macroglobulin binding to low-density lipoprotein receptor-related protein 1, which was alleviated by pretreatment of cells with N-acetylcystein. 2′-Hydroxycinnamaldehyde decreased the extracellular pepsin concentration significantly in a low-density lipoprotein receptor-related protein 1- and α-2-macroglobulin-dependent manner. The anti-invasive effect of 2′-hydroxycinnamaldehyde was mitigated with receptor-associated protein pretreatment, suggesting that low-density lipoprotein receptor-related protein 1 is essential for the effects of 2′-hydroxycinnamaldehyde. From these data, we suggest that 2′-hydroxycinnamaldehyde increases the cysteine thiol oxidation status of low-density lipoprotein receptor-related protein 1 extracellular domains, which results in α-2-macroglobulin ligand binding stimulation. Therefore, pepsin clearance in a low-density lipoprotein receptor-related protein 1-α-2-macroglobulin-dependent manner might be an important molecular mechanism in 2′-hydroxycinnamaldehyde exerting its anti-invasive action on breast cancer cells. Furthermore, our data may provide an opportunity to promote the importance of the thiol oxidation status of cell surface receptor proteins for regulating cellular signaling pathways that are important in cancer progression.

Effects of Concentration and Reaction Time of Trypsin, Pepsin, and Chymotrypsin on the Hydrolysis Efficiency of Porcine Placenta.

This study investigated the effects of three proteases (trypsin, pepsin and chymotrypsin) on the hydrolysis efficiency of porcine placenta and the molecular weight (Mw) distributions of the placental hydrolysates. Because placenta was made up of insoluble collagen, the placenta was gelatinized by applying thermal treatment at 90 ℃ for 1 h and used as the sample. The placental hydrolyzing activities of the enzymes at varying concentrations and incubation times were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel permeation chromatography (GPC). Based on the SDS-PAGE, the best placental hydrolysis efficiency was observed in trypsin treatments where all peptide bands disappeared after 1 h of incubation as compared to 6 h of chymotrypsin. Pepsin hardly hydrolyzed the placenta as compared to the other two enzymes. The Mw distribution revealed that the trypsin produced placental peptides with Mw of 106 and 500 Da. Peptides produced by chymotrypsin exhibited broad ranges of Mw distribution (1-20 kDa), while the pepsin treatment showed Mw greater than 7 kDa. For comparisons of pre-treatments, the subcritical water processing (37.5 MPa and 200 ℃ of raw placenta improved the efficiency of tryptic digestions to a greater level than that of a preheating treatment (90 ℃ for 1 h). Consequently, subcritical water processing followed by enzymatic digestions has the potential of an advanced collagen hydrolysis technique.

Особливості періодичної активності шлунка за умов дисбалансу NO-ергічної системи

Nitric oxide is the main inhibitory mediator of the gastrointestinal smooth muscles’ relaxation which stimulates duodenal mucus and bicarbonate secretion. More recent studies have demonstrated that NO also protected the gastrointestinal tract by inhibiting gastric acid secretion. In this study we investigated gastric secretory and motor activity considering the NO imbalance condition. The experiments were carried out on male white laboratory rats (200–230 g). The control group was treated with 0.9% NaCl solution. The injections of NO donator (1.5 mg/kg of 0.1% (Sigma-Aldrich) sodium nitroprusside solution) were made in the second and the third groups during 6 and 12 days. The fourth and the fifth group were treated with NO synthesis inhibitor (40 mg/kg of 1% solution (Sigma-Aldrich) Nω-nitro-L-arginine) during 6 and 12 days respectively. Recording of gastric myoelectric activity (GMA) and gastric juice collection were carried out under anesthesia (ketamine, 110 mg/kg). Next, its volume, pH, glycoprotein and pepsin were measured. Within 6-days stimulation of NO excess decreased gastric juice volume by 47% and increased pH compared to control samples. Pepsin level increased by 62% and glycoprotein level decreased by 68% compared to the checkpoint. After 6 days of L-NNA injections we observed the increase of gastric juice secretion volume (78%) and pH level, however, pepsin concentration remained unchanged. Glycoprotein level increased by 21% compared to control samples. After 12 day NO synthesis inhibitor injections gastric secretion volume increased by 85%. Gastric juice pH level was 200% higher than the control value and exceeded gastric juice pH level (62%) in the third group. In addition, pepsin level tended to decrease when NO deficiency simulation was prolonged. Glycoprotein level decreased by 41% compared to control samples and by 51% compared to the third group. Pepsin level decreased after 12 day NO-inhibitor injections as gastric juice pH level increased. After 12 day Na-nitroprusside treatment, gastric myoelectric index decreased by 42% compared to the checkpoint. The type of contractions is typical to the I phase of the basic electrical rhythm (BER). Also, retrograde entrainment of duodenal rhythm took place. After 6 day L-NNA injections, GMA was the same as the period between II and III phase of BER. Late second and early third phases predominated, while the I phase wasn’t detected during the recording. In case of long-lasting disorder of NO-system, motor index value significantly differed from the control group samples and depended on the duration of NO-synthase blocking. On the 6th day of L-NNA treatment, the level of motor index increased 1.5 times. GMA phases could be identified only on the basis of motor index values. Stomach’s own rhythms disappeared and duodenogastric reflux resulted in domination of duodenal rhythms. After 12 day L-NNA injections, duration of the II and III phases increased while the I phase of gastric BER disappeared; gastric motor index decreased by 27%. After considering the results of the current investigation, it can be stated that NO system imbalance leads to desynchronization of gastric active phases and, perhaps, reassigns the influence of different compensatory-adaptive mechanisms. The longer is the L-NNA treatment, the more gastric functions are imbalanced and the stronger is the process of destruction.

Variation in gastric pH may determine kiwifruit's effect on functional GI disorder: an in vitro study.

Consumption of kiwifruit is reported to relieve symptoms of functional gastrointestinal (GI) disorder. The effect may be related to the proteases in kiwifruit. This in vitro study aimed to measure protein hydrolysis due to kiwifruit protease under gastric and duodenal conditions. A sequence of experiments incubated meat protein, with and without kiwifruit, with varying concentrations of pepsin and hydrochloric acid, at 37 °C for 60 min over the pH range 1.3–6.2 to simulate gastric digestion. Duodenal digestion was simulated by a further 120 min incubation at pH 6.4. Protein digestion efficiency was determined by comparing Kjeldahl nitrogen in pre- and post-digests. Where acid and pepsin concentrations were optimal for peptic digestion, hydrolysis was 80% effective and addition of kiwifruit made little difference. When pH was increased to 3.1 and pepsin activity reduced, hydrolysis decreased by 75%; addition of kiwifruit to this milieu more than doubled protein hydrolysis. This in vitro study has shown, when gastric pH is elevated, the addition of kiwifruit can double the rate of hydrolysis of meat protein. This novel finding supports the hypothesis that consumption of kiwifruit with a meal can increase the rate of protein hydrolysis, which may explain how kiwifruit relieves functional GI disorder.

Role of pepsin and pepsinogen: Linking laryngopharyngeal reflux with otitis media with effusion in children

To analyze the relationship between laryngopharyngeal reflux (LPR) represented by pepsin and pepsinogen, and pathogenesis of otitis media with effusion (OME). Prospective case-control study. Children with OME who required adenoidectomy and tympanostomy/tympanostomy tubes placement were enrolled in OME group, whereas children with adenoid hypertrophy (AH) who required adenoidectomy and individuals who required cochlear implantation (CI) were enrolled in AH and CI groups, respectively. Pepsinogen mRNA and protein levels were assessed by real-time fluorescence-based quantitative polymerase chain reaction and immunohistochemistry in adenoid specimens from the OME and AH groups. Pepsin and pepsinogen concentrations were evaluated by enzyme-linked immunosorbent assay in middle ear fluid and plasma from the OME and CI groups. The levels of pepsinogen protein expressed in cytoplasm of epithelial cells and clearance under epithelial cells in adenoid specimens from the OME group were significantly higher than those in the AH group. Furthermore, the concentrations of pepsin and pepsinogen in the OME group were 51.93±11.58 ng/mL and 728±342.6 ng/mL, respectively, which were significantly higher than those in the CI group (P<.001). In addition, the concentrations of pepsin in dry ears were significantly lower than those in serous and mucus ears in the OME group (F=22.77, P<.001).Finally, the concentration of pepsinogen in middle ear effusion was positively correlated with the expression intensity of pepsinogen protein in cytoplasm of epithelial cells (r=0.73, P<.05) in the OME group. Pepsin and pepsinogen in middle ear effusion are probably caused by LPR and may be involved in the pathogenesis of OME. 3b.

Prediction of crude protein digestibility of animal by-product meals for dogs by the protein solubility in pepsin method.

Animal by-product meals have large variability in crude protein (CP) content and digestibility. In vivo digestibility procedures are precise but laborious, and in vitro methods could be an alternative to evaluate and classify these ingredients. The present study reports prediction equations to estimate the CP digestibility of meat and bone meal (MBM) and poultry by-product meal (PM) using the protein solubility in pepsin method (PSP). Total tract CP digestibility of eight MBM and eight PM samples was determined in dogs by the substitution method. A basal diet was formulated for dog maintenance, and sixteen diets were produced by mixing 70% of the basal diet and 30% of each tested meal. Six dogs per diet were used to determine ingredient digestibility. In addition, PSP of the MBM and PM samples was determined using three pepsin concentrations: 0·02, 0·002 and 0·0002%. The CP content of MBM and PM ranged from 39 to 46% and 57 to 69%, respectively, and their mean CP digestibility by dogs was 76 (2·4) and 85 (2·6) %, respectively. The pepsin concentration with higher Pearson correlation coefficients with the in vivo results were 0·0002% for MBM (r 0·380; P=0·008) and 0·02% for PM (r 0·482; P=0·005). The relationship between the in vivo and in vitro results was better explained by the following equations: CP digestibility of MBM=61·7+0·2644×PSP at 0·0002% (P=0·008; R (2) 0·126); and CP digestibility of PM=54·1+0·3833×PSP at 0·02% (P=0·005; R (2) 0·216). Although significant, the coefficients of determination were low, indicating that the models were weak and need to be used with caution.

The role of gastro-esophageal reflux (GER) in systemic sclerosis and lung fibrosis

Systemic sclerosis (SSc) is an autoimmune condition characterized by tissue fibrosis of the skin and internal organs. A significant subgroup of SSc patients develops progressive interstitial lung disease(ILD) leading to pulmonary fibrosis similar to IPF (idiopathic pulmonary fibrosis). Gastro-esophageal reflux (GER) has been suggested as a driving factor in the pathogenesis of both SSc-ILD and IPF. The esophagus is affected in 50-82% of patients with SSc. Gastric reflux may be liquid, gaseous, or particulate; acid or nonacid; distal (localized to the distal oesophagus) or proximal (reaching the proximal oesophagus and pharynx). Reflux to the proximal oesophagus, which is intuitively linked to microaspiration into the lungs, appears to be quite common in patients with ILD-SSc and IPF. Importantly, a significant proportion of GER reflux is asymptomatic. Concentration of pepsin and bile acids in broncho-alveolar lavage (BAL) and exhaled breath condensate (EBC) have been investigated as biomarkers of microaspiration in various respiratory diseases. The confirmation of a causative link of microaspiration in the genesis and progression of lung fibrosis would have a major impact in the management of ILD-SSc patients. It is likely that proteases such as pepsin, and not the acidity, are the primary target for future therapies. Potent inhibitors specific for proteases, e.g. pepstatin, are available and have been tested in phase-III clinical trials.

Management of experimental hypochlorhydria with iron deficiency by the composite extract of Fumaria vaillantii L. and Benincasa hispida T. in rat

The aim of the present study was to search the effective ratio of whole plant of Fumaria vaillantii Loisel (Fumaria vaillantii L.) and fruit of Benincasa hispida Thunb. (Benincasa hispida T.) in composite form, namely “FVBH” for the management of hypochlorhydria along with iron deficiency in male albino rats. Hypochlorhydria refers to suppression of hydrochloric acid secretion by the stomach. Hypochlorhydria was induced by ranitidine in this study. We used four composite extracts of the mentioned plant and fruit with different ratios (1:1, 1:2, 2:1, and 3:2) for searching the most effective composite extract for the correction of hypochlorhydria. Gastric acidity is an important factor for iron absorption. Thus, hypochlorhydria causes iron deficiency in rat and it was prevented significantly by the extract treatment at the ratio of 1:1 of the said plant and fruit. The correction of iron deficiency by the composite extract was compared with iron supplementation to hypochlorhydric rat. It was found that preadministration followed by coadministration of FVBH-1 (1:1) able to prevent the ranitidine-induced hypochlorhydria and iron deficiency. The composite extract, FVBH-1 (1:1) significantly (P<0.05) increased the pepsin concentration, chloride level in gastric juice, iron levels in serum and liver along with blood hemoglobin level than other ratios used here. Hence, it can be concluded that FVBH-1 (1:1) is an effective herbal formulation for the management of hypochlorhydria and related iron deficiency.

Chemical and biophysical properties of gelatins extracted from alkali-pretreated skin of cuttlefish (Sepia officinalis) using pepsin

Gelatins from alkali-pretreated skin of cuttlefish (Sepia officinalis) were extracted with different concentrations of pepsin at pH2.0 and characterized. The increase of enzyme concentration increased the yield of gelatin extraction. The yields of gelatins G5, G10 and G15, extracted, respectively, with 5, 10, and 15U of pepsin/g of alkali-treated skin of cuttlefish, were 6.59%, 7.69% and 9.22%, respectively, while in the absence of pepsin (G0) the yield was only 2.68%. Nevertheless, the extraction of gelatin from alkali-pretreated skin of cuttlefish with pepsin at pH2.0 affected the molecular weight, biophysical and functional properties of resulting gelatins. Gelatin extracted without pepsin showed the higher gel strength, and transition, gelling and melting temperatures, which are slightly higher than G5. All of these values decreased with increasing enzyme concentration. In addition, foam expansion (FE) was affected by enzymatic treatment, and the values decreased as pepsin increased. Nevertheless, the partially hydrolyzed gelatins showed the same emulsifying properties.

Pepsin concentrations are elevated in the bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis after lung transplantation

BackgroundAspiration of gastroesophageal refluxate has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF) and the progression of bronchiolitis obliterans syndrome after lung transplantation. The goals of the present study were to identify lung transplant patients at the greatest risk of aspiration and to investigate the causative factors. Materials and methodsFrom September 2009 to November 2011, 252 bronchoalveolar lavage fluid (BALF) samples were collected from 100 lung transplant patients. The BALF pepsin concentrations and the results of transbronchial biopsy, esophageal function testing, barium swallow, and gastric emptying scan were compared among those with the most common end-stage lung diseases requiring lung transplantation: IPF, chronic obstructive pulmonary disease, cystic fibrosis, and α1-antitrypsin deficiency. ResultsPatients with IPF had higher BALF pepsin concentrations and a greater frequency of acute rejection than those with α1-antitrypsin deficiency, cystic fibrosis, or chronic obstructive pulmonary disease (P = 0.037). Moreover, the BALF pepsin concentrations correlated negatively with a lower esophageal sphincter pressure and distal esophageal amplitude; negatively with distal esophageal amplitude and positively with total esophageal acid time, longest reflux episode, and DeMeester score in those with chronic obstructive pulmonary disease; and negatively with the upright acid clearance time in those with IPF. ConclusionsOur results suggest that patients with IPF after lung transplantation are at increased risk of aspiration and a greater frequency of acute rejection episodes, and that the risk factors for aspiration might be different among those with the most common end-stage lung diseases who have undergone lung transplantation. These results support the role of evaluating the BALF for markers of aspiration in assessing lung transplant patients as candidates for antireflux surgery.

Factors affecting the bioaccessibility of fluoride from seafood products

Fluoride is considered important for health because of its beneficial effect on the prevention of dental caries and on bone development in the child population. However, excessive intake has negative effects. The main pathway for exposure is oral, through consumption of drinking water, and some food products. Therefore its bioaccessibility (quantity of the element solubilized during the digestive process) is a parameter to be considered when estimating the risk/benefit associated with this element. The aim of the present study was to evaluate the influence of the digestion phase, gastrointestinal digestion factors (pH, pepsin and bile salt concentrations) and the presence of cations on the bioaccessibility of fluoride from seafood products. The results show that the solubilization of fluoride takes place entirely during the gastric phase. Its bioaccessibility is strongly influenced by conditions that favor the formation of insoluble complexes of fluoride with other elements present in the matrix. The factors that are most influential in reducing its bioaccessibility are the increase in pH in the gastric phase, the presence of cations, especially in the intestinal phase, and a low concentration of bile salts.

Airway Pepsin Levels in Otherwise Healthy Surgical Patients Receiving General Anesthesia With Endotracheal Intubation

Airway pepsin has been increasingly used as a potentially sensitive and quantifiable biomarker for gastric-to-pulmonary aspiration, despite lack of validation in normal control subjects. This study attempts to define normal levels of airway pepsin in adults and distinguish between pepsin A (exclusive to stomach) and pepsin C (which can be expressed by pneumocytes). We performed a prospective study of 51 otherwise healthy adult patients undergoing elective extremity orthopedic surgery at a single tertiary-care academic medical center. Lower airway samples were obtained immediately following endotracheal intubation and just prior to extubation. Total pepsin and pepsin A concentrations were directly measured by an enzymatic activity assay, and pepsin C was subsequently derived. Pepsinogen/pepsin C was confirmed by Western blot analyses. Baseline characteristics were secondarily compared. In all, 11 (22%; 95% CI = 9.9%-33%) had detectable airway pepsin concentrations. All 11 positive specimens had pepsin C, without any detectable pepsin A. Pepsinogen/pepsin C was confirmed by Western blot analyses. In a multivariate logistic regression, men were more likely to have airway pepsin (OR, 12.71, P = .029). Enzymatically active pepsin C, but not the gastric-specific pepsin A, is frequently detected in the lower airways of patients who otherwise have no risk for aspiration. This suggests that nonspecific pepsin assays should be used and interpreted with caution as a biomarker of gastropulmonary aspiration, as pepsinogen C potentially expressed from pneumocytes may be detected in airway samples.

Detection of Key Factors Affecting Lycopene in Vitro Accessibility

On the basis of a Plackett-Burman experimental design for a resolution IV level obtained via a foldover strategy, the effect of 11 factors on lycopene in vitro accessibility was investigated. The selected factors were thermal treatment (X1), olive oil addition (X2), gastric pH (X3), gastric digestion time (X4), pepsin concentration (X5), intestinal pH (X6), pancreatin concentration (X7), bile salts concentration (X8), colipase addition (X9), intestinal digestion time (X10), and intestinal digestion speed (X11). Tomato passata was used as a natural source of lycopene. Samples were collected after gastric and intestinal digestion, and from the micellar phase, to quantify the (all-E)-lycopene and its (Z)-isomers by HPLC. Except for X3, X6, X7, and X11, the other factors studied explained lycopene in vitro accessibility, mainly regarding intestinal digestion, with R(2) values ≥ 0.60. Our results showed that the accessibility of lycopene is influenced by the conditions applied during in vitro intestinal digestion.