Comparison of in vitro erosion protocols in bovine teeth to simulate natural erosion lesion: analysis of mechanical properties and surface gloss

Abstract Objective The aim of this study was to compare two in vitro erosion protocols, in which one simulates in vivo conditions experienced by patients with gastroesophageal disorders or bulimia (HCl-pepsin protocol), and the other simulates the diet of an individual who consumes a high volume of erosive beverages (citric acid protocol). In addition, the mechanical properties and surface gloss of eroded human dentin were compared with those of sound human dentin. Materials and Methods Blocks of cervical dentin were used: sound human dentin (n=10), human dentin with erosive lesions (n=10), and bovine dentin (n=30). Twenty bovine blocks were subjected to either of two erosion protocols (n=10/protocol). In the first protocol, samples were demineralized using HCl-pepsin solution, then treated with trypsin solution. In the second protocol, samples were demineralized with 2% citric acid. Toothbrushing was performed in both protocols using a toothbrushing machine (15 s with a 150 g load). Ten bovine dentin blocks were not subjected to any erosive treatment. All samples of bovine and human dentin were analyzed to obtain Martens hardness values (MH), elastic modulus (Eit*) and surface gloss. One-way ANOVA and Tukey's test were performed to analyze the data (α=0.05). Results Sound human and eroded human dentin groups showed similar MH and Eit* values (p>0.05); however, sound human dentin showed a higher surface gloss value when compared to eroded human dentin (p<0.05). Sound bovine dentin and HCl-pepsin-treated bovine dentin treatments resulted in similar values for both MH and Eit* (p>0.05), but HCl-pepsin-treated bovine dentin and citric acid-treated bovine dentin resulted in lower surface gloss than sound bovine dentin (p<0.05). Conclusions The HCl-pepsin protocol modified bovine dentin properties that could be similar to those that occur on human dentin surfaces with erosive lesions.

Cross-sectional study of Trichinella spp in pigs in CDR, Nepal using pepsin digestion and ELISA serology.

This epidemiological cross-sectional study was conducted in five major pig-producing districts of CDR, Nepal from November 2006 to April 2007. A total of 576 slaughtered pigs were randomly selected and diaphragmatic crus muscles (n = 551), corresponding sera (n = 487) and sera only (n = 25) were collected from them. Meat samples were examined by pepsin digestion to evaluate for larvae of Trichinella spp. The sera were investigated using ELISA to evaluate for antibodies against T. spiralis. The doubtful and positive sera from the ELISA test were investigated by end-point ELISA, and the Western blot was used for confirmatory diagnosis. Pepsin digestion did not detect the larvae of Trichinella spp. AB-ELISA showed 2 positive and 14 doubtful results, out of 344 sera analyzed. End-point ELISA and the Western blot had revealed that all 16 samples were truly negative. A questionnaire revealed no rodent control (70%), left over feeding practices (65%), dumping of farm waste (82.5%) and uncooked meat was being used as feed (100%). This study reveals that Trichinella spp has a low prevalence.

Role of pepsin in modifying the allergenicity of bhetki (Lates calcarifer) and mackerel (Rastrelliger kanagurta) fish.

The effect of pepsin digestion on the allergenicity of raw and thermally processed (boiled and fried) fish muscle extracts of two widely consumed fishes bhetki (Lates calcarifer) and mackerel (Rastrelliger kanagurta) was studied. Sere were collected from 110 patients who were hypersensitive to fish, as evidenced by their clinical history, symptoms and positive skin-prick test results. The various extracts after digestion with pepsin at different times of incubation were tested for specific IgE-binding activity by ELISA and immunoblotting with patients' sera. All the extracts of both the fishes retained their allergenicity as evidenced by ELISA and immunoblotting. In bhetki, maximum allergenicity was found in the pepsin-digested fried extract, whereas similar treatment decreased the allergenicity in fried mackerel. Results showed that raw as well as thermally processed allergens of both the fishes maintained strong allergenicity, even after digestion with pepsin for different time periods. The study revealed that the fish proteins played an important role in manifestation of allergy, due to their stable structure, which was retained even after pepsin and heat treatment.

Taurine prevents collagen abnormalities in high fructose-fed rats.

BACKGROUND & OBJECTIVE: Accumulation of collagen and changes in its physiochemical properties contribute to the development of secondary complications of diabetes. We undertook this study to see the effects of taurine on the content and characteristics of collagen from tail tendon of rats fed with high fructose diet. METHODS: The rats were divided into four groups of six each: control group (CON), taurine-supplemented control group (CON+TAU), taurine supplemented (FRU+TAU) and not supplemented fructose-fed group (FRU). The physico-chemical properties of collagen isolated from the tail tendon were studied. RESULTS: Fructose administration caused accumulation of collagen in tail tendon. Enhanced glycation and advanced glycation end products (AGE)-linked fluorescence together with alterations in aldehyde content, solubility pattern, susceptibility to denaturing agents and shrinkage temperature were observed in fructose-fed rats. Elevated b component of type I collagen was evidenced from the SDS gel pattern of collagen from the fructose-fed rats. Simultaneous administration of taurine alleviated these changes. INTERPRETATION & CONCLUSION: Taurine administration to fructose-rats had a positive influence on both quantitative and qualitative properties of collagen. The results of the present study suggested a role for the action of taurine in delaying diabetic complications and the possible use of taurine as an adjuvant therapeutic measure in the management of diabetes and its complications.