Pulp Sections Research Articles

Dental pulp stones and their correlation with metabolic diseases.

Dental pulp calcifications or pulp stones are calcified structures found in dental pulp, mostly around or enclosing a blood vessel. The formation of these calcifications begins with concentric layers of calcified tissue within which remnants of necrotic and calcified cells may be present. The calcifications of thrombi in blood vessels, called phleboliths, may also serve as nidi for denticles. In metabolic diseases such as diabetes, hypertension or poor periodontal health, there are obvious changes in blood vessels and vascularization. In our study, we observed histopathological sections of dental pulp and correlated systemic diseases such as diabetes and hypertension with poor periodontal health and dental pulp stones. The aim of our study was to evaluate the histopathology of dental pulp stones, their distribution among various age groups and sexes and to identify any correlations between pulp stone formation and systemic diseases such as type II diabetes and hypertension. Samples from 100 patients with metabolic diseases such as type II diabetes and hypertension were collected. The pulp was extirpated from the teeth that were undergoing root canal treatment, and the teeth were extracted. The collected pulp sample was fixed in 10% formaline neutral buffer, subjected to routine histopathological procedures and stained with haematoxylin and eosin. The pulp of teeth extracted for orthodontic treatment was considered a control for patients with no metabolic disease. There was a definite relationship between increased pulp stones and metabolic diseases such as type II diabetes and hypertension; likewise, poor periodontal health was significantly related to pulp stones.

The Effect of Household Food Processing on Pesticide Residues in Oranges (Citrus sinensis)

In this study, the effect of various household food-processing methods (washing, peeling, processing into jam and fruit juice, freezing, storage) on pesticide residues (abamectin, buprofezin, ethoxazole, imazalil, and thiophanate-methyl) in oranges was investigated. Residue analyses were performed by quick-easy-cheap-efficient-rugged-safe (QuEChERS) extraction and liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS) analysis. The limit of quantification of the method for each pesticide was 10 µg/kg. Physicochemical properties of the pesticides and the type of the food process had a considerable effect on the fate of pesticide residue. Pesticide residues were mostly dispersed on orange peels and washing with tap water decreased the residue levels by 26-84%. The amount of residue in oranges was reduced by 63-100% during fruit juice processing, while residues were removed by 90-100% after jam processing. Pesticides with a high octanol-water coefficient were absorbed by the wax of the orange peel, therefore they remained on the peel and could not easily be removed by washing. Moreover, pesticides with lower water solubility did not diffuse easily through the fruit juices from the pulp section of the fruit. The processing factor was greater than 1 for the separation of the orange peel and less than 1 for the washing step and jam and fruit juice productions.

Thermodynamic analysis of a cogeneration system in pulp and paper industry under singular and hybrid operating modes

In the present study, a thermodynamic analysis of a cogeneration system in a pulp and paper industry under different operating modes i.e., singular and hybrid with a variable ambient temperature is conducted according to actual operating data. For singular operating mode, the power boiler is only employed using natural gas while for hybrid operating mode, the power boiler with the recovery boiler is employed using natural gas and black liquor as main fuels, respectively. The results show that for hybrid operating mode in comparison with the singular one, the thermal efficiency of turbine and condenser is enhanced by 1.36 and 7.7%, respectively while it is reduced by 2.8% for the power boiler. In addition, the overall thermal efficiency under singular and hybrid operating modes is 87.4 and 53.7%, respectively. For hybrid operating mode, the exergy destruction of power boiler decreases by almost 10% compared with that for the singular operating mode. Also, at hybrid operating mode, the soda is recovered with a mass flow rate of 33 tons/hour that is required for the cooking process in the chemical pulp section and additionally the consumption of natural gas in the power boiler is reduced by 11.8%.

Transcriptomics‐based identification and characterization of genes related to sugar metabolism in ‘Hongshuijing’ pitaya

Sugar composition not only affects fruit flavor but is also an important determinant of fruit taste and consumer preference. In this study, changes in the sugar content and sugar-metabolizing enzymes were investigated from different sections of various fruit development phases of ‘Hongshuijing’ pitaya (Hylocereus monacanthus). Genes related to sugar metabolism were also screened by transcriptome analyses. The results indicated that glucose was the major sugar in mature pitaya fruit, and was mainly regulated by vacuolar acid invertase (VAI) and sucrose synthase (SS) (degradative direction). Sugar accumulation varied in pulp between different sections of the pitaya fruit. VAI, neutral invertase (NI) and SS (degradative direction) are crucial enzymes for sugar accumulation in pitaya. The expression of 17 genes related to sucrose metabolism obtained from seven databases [NCBI non-redundant protein database (Nr), NCBI non-redundant nucleotide sequence database (Nt), EuKaryotic Orthologous Groups (KOG), The Protein Families (Pfam), Kyoto Encyclopedia of Genes and Genomes (KEGG), Swiss-prot, and Gene Ontology (GO)] were analyzed in different pitaya pulp sections. HpVAI1 had the highest relative expression level on the 29th day after pollination (DAP). Positive correlations were found between HpVAI1 expression and VAI activity; HpNI4 and NI activity; HpSS2, HpSS5, and SS activity (synthetic direction), indicating that HpVAI1, HpNI4, and HpSS2 and HpSS5 were involved in the regulation of VAI, NI, and SS (synthetic direction), respectively. HpVAI1 and HpNI4 regulated sucrose degradation and the accumulation of glucose and fructose, while HpSS2 and HpSS5 regulated sucrose synthesis. These results suggest that HpVAI1 plays a key role in sugar metabolism during fruit development of ‘Hongshuijing’ pitaya. The results of this study provide new information about sugar metabolism in pitaya fruit that could help improve fruit quality and the breeding of new cultivars.

C5L2 Regulates DMP1 Expression during Odontoblastic Differentiation

The presence of stem cells within the dental-pulp tissue as well as their differentiation into a new generation of functional odontoblast-like cells constitutes an important step of the dentin-pulp regeneration. Recent investigations demonstrated that the complement system activation participates in 2 critical steps of dentin-pulp regeneration: pulp progenitor’s recruitment and pulp nerve sprouting. Surprisingly, its implication in odontoblastic differentiation has not been addressed yet. Since the complement receptor C5a receptor-like 2 (C5L2) is expressed by different stem cells, the aim of this study is to investigate if the dental pulp stem cells express C5L2 and if this receptor participates in odontoblastic differentiation. Immunohistochemistry performed on human third molar pulp sections showed a perivascular co-localization of the mesenchymal stem cell markers STRO1 and C5L2. In vitro immunofluorescent staining confirmed that hDPSCs express C5L2. Furthermore, we determined by real-time polymerase chain reaction that the expression of C5L2 is highly modulated in human dental pulp stem cells (hDPSCs) undergoing odontoblastic differentiation. Moreover, we showed that this odontogenesis-regulated expression of C5L2 is specifically potentiated by the proinflammatory cytokine TNFα. Using a C5L2-siRNA silencing strategy, we provide direct evidence that C5L2 constitutes a negative regulator of the dentinogenic marker DMP1 (dentin matrix protein 1) expression by hDPSCs. Our findings suggest a direct correlation between the odontoblastic differentiation and the level of C5L2 expression in hDPSCs and identify C5L2 as a negative regulator of DMP1 expression by hDPSCs during the odontoblastic differentiation and inflammation processes. This work is the first to demonstrate the involvement of C5L2 in the biological function of stem cells, provides an important knowledge in understanding odontoblastic differentiation of dental pulp stem cells, and may be useful in future dentin-pulp engineering strategies.

Staining Power of Natural and Artificial Dyes after At-home Dental Bleaching

Bleached enamel surfaces may undergo changes and retain more dye, which is a reason to recommend the reduction/suspension of foods with dyes during dental bleaching. Evaluate the effects of the action of natural and artificial dyes on the bleached enamel of extracted human teeth. Fifty human premolars were used, which were distributed in 5 groups (n = 10) according to the following staining solutions: GW (distilled water); GB (beet); Gca (caramel); GC (carmine); and GR (red 40). After the removal of the root and pulp section, the teeth were embedded in acrylic resin blocks, stored in artificial saliva, and kept at 37°C. At-home bleaching was performed using 16% carbamide peroxide (CP) for 3 hours daily for 3 weeks. After each daily session of bleaching, the specimens were exposed to the dye solution twice a day for 5 min; one of these exposures was performed immediately after bleaching. The color was recorded using a spectrophotometer according to the CIE Lab system (Δ E) for the following periods: baseline, during bleaching (after 1st, 2nd, and 3rd week) and post-bleaching (after 1 week and 1 month). The color was evaluated by two-way analysis of variance and Tukey's test (α=0.05). There was effective dental bleaching for all groups: GW (18.5 ± 6.1), GB (19.9 ± 4.4), Gca (18.9 ± 6.1), GC (20.2 ± 4.6), and GR (19.3 ± 4.2), p <0.01. No color rebound was observed after 1 week and 1 month (p >0.05). The exposure to beet, carmine, caramel, and red 40 dyes did not interfere with the effectiveness of dental bleaching using 16% CP. Dyes consumption during bleaching did not affect the effectiveness of dental bleaching.

Analysis of proteoglycan expression in human dental pulp

Proteoglycans are glycosylated proteins which have covalently attached highly anionic glycosaminoglycans. They can be located on the extracellular matrix, cell membrane or intracellular granules. To date, few studies have reported the presence of proteoglycans in human dental pulp. ObjectiveThe aim of this study was, therefore, to analyze the expression of lumican, versican and glypican proteoglycans in deciduous and permanent human dental pulp by real-time polymerase chain reaction (q-PCR) and immunofluorescence. DesignHealthy human dental pulps were used: 13 from permanent teeth (group 1) and eight from deciduous teeth (group 2). Versican, lumican and glypican (glypican-1 to 6) gene expressions were quantitatively evaluated by real-time PCR technique, using the expression of the endogenous gene GAPDH as control. Pulp sections were submitted to immunostaining procedure with fluorescence labelling, the tissues being fixed and incubated with well-characterized monoclonal and polyclonal antibodies against proteoglycan epitopes, including anti-versican and anti-lumican. Comparisons among the groups of the quantitative scores for each proteoglycan were analyzed using the t-test and ANOVA (P < 0.05). ResultsThe real-time PCR analysis showed expression of versican and lumican proteoglycans in the two groups, with significant predominance of lumican gene (P = 0.03). Considering the glypican genes, glypican-3 was the proteoglycan most significantly expressed in permanent pulps (P < 0.001), while glypican-2 was not expressed in this tissue. The immunofluorescence quantification exhibited no significant differences between lumican and versican among the pulps and groups. ConclusionsThe lumican gene was more expressed than versican and glypican-3 was the isoform more expressed in permanent pulp compared to deciduous.

Teneurin-2 presence in rat and human odontoblasts.

Teneurins are transmembrane proteins consisting of four paralogues (Ten-1-4), notably expressed in the central nervous system during development. All teneurins contain a bioactive peptide in their carboxyl terminal named teneurin C-terminal associated peptide (TCAP). The present study analyzed the detailed distribution of teneurin-2-like immunoreactive (Ten-2-LI) cells in developing and mature rat molar teeth, as well as in mature human dental pulps. Ten-2 and TCAP-2 genic expressions were also evaluated in rat and human dental pulps. Finally, Ten-2-LI cells were analyzed during the repair process after dentin-pulp complex injury in rat lower molar teeth. For this, histological sections of rat molar teeth and human dental pulps were submitted to immunohistochemical techniques, while total RNA from developing rat teeth and mature human dental pulps were submitted to conventional RT-PCR. Ten-2-LI cells were evident in the initial bell stage of rat molar teeth development, especially in ectomesenchymal cells of the dental papilla. Ten-2-LI odontoblasts showed strong immunoreactivity in rat and human mature teeth. Ten-2 and TCAP-2 genic expressions were confirmed in rat and human dental pulps. Dentin-pulp complex injury resulted in a decrease of Ten-2-LI odontoblasts after traumatic injury. Interestingly, Ten-2-LI cells were also evident in the pulp cell-rich zone in all postoperative days. In conclusion, Ten-2-LI presence in rat and human odontoblasts was demonstrated for the first time and Ten-2/TCAP-2 genic expressions were confirmed in rat and human dental pulps. Furthermore, it was revealed that Ten-2-LI rat odontoblasts can be modulated during the regenerative process.

Overcoming the caking phenomenon in olive mill wastes

The use of olive mill wastes (orujillo) within coal fired power stations in the UK has led to unexpected difficulties with material caking within the fuel handling plant. This study replicated orujillo caking on a laboratory scale using a planetary ball mill and explored the impact of mill parameters (speed, volume, and duration) on the caking phenomenon. The impact of orujillo composition was examined for 4 sections of fresh and dried orujillo (whole, pulp 0–850μm, pulp 850–3350μm, and cluster 3350μm+) for set milling conditions. Caking was induced by heat generation within the mill and was most prevalent in the pulp section of orujillo. Caking was brought on by a glass transition step, which was measured to be around 97–98°C for a moisture content of 6–7% in a differential scanning calorimeter (DSC). Caking was the result of the bulk moisture content (14–18%) being higher than the standard moisture content of orujillo (<12%), and can be mitigated through drying. Thus the key to overcoming orujillo caking in fuel handling plants is through moisture content control. Additionally, as the caking issue is most prevalent in the pulp section, all fines below the required combustion particle size (typically <1mm) should be removed prior to comminution and sent directly to the burner. This would also reduce the comminution load by nearly 50%, increase the energy potential of the fuel, and remove the most problematic section of orujillo from the fuel handling plant.

Survival of the Apical Papilla and Its Resident Stem Cells in a Case of Advanced Pulpal Necrosis and Apical Periodontitis

IntroductionApical papilla represents a source of an enriched mesenchymal stem cell (MSC) population (stem cells of the apical papilla [SCAPs]) that modulates root development and may participate in regenerative endodontic procedures in immature teeth with pulp necrosis. The characteristics and phenotype of this tissue in the presence of inflammation are largely unknown. The purpose of this study was to characterize a human apical papilla sample that was isolated from an immature tooth with pulp necrosis and apical periodontitis. MethodsInflamed periapical tissue that included part of the apical papilla (apical papilla clinical sample [CS]) was collected from an immature mandibular premolar previously diagnosed with pulp necrosis and apical periodontitis during an apexification procedure. Harvested cells from this tissue (SCAP CS) were compared with inflamed periapical progenitor cells (IPAPCs) and normal SCAP (SCAP-RP89) in flow cytometry and quantitative osteogenesis experiments. Part of the issue was further processed for immunohistochemistry and compared with apical papilla and coronal pulp sections from normal immature teeth as well as inflamed periapical tissues from mature teeth. ResultsSimilar to SCAP-RP89, 96.6% of the SCAP CS coexpressed the MSC markers CD73, CD90, and CD105, whereas only 66.3% of IPAPCs coexpressed all markers. The SCAP CS showed a significantly greater mineralization potential than both SCAP-RP89 and IPAPCs. Finally, immunohistochemical analysis revealed moderate infiltration of cells expressing the inflammatory markers CD45/68 in the apical papilla CS and prominent CD24, CD105, and von Willebrand factor expression. ConclusionsUnder inflammatory conditions, human apical papilla was found moderately inflamed with retained SCAP vitality and stemness and increased osteogenic and angiogenesis potential.

Technology selection and evaluation in Iran's pulp and paper industry using 2-filterd fuzzy decision making method

In recent years, the pulp and paper industry has changed a lot and products have been constructed in quite different methods using new technologies. It can be due to the emergence of challenges and constraints such as shortage of raw materials, energy consumption (fossil fuels, electric, etc.), management of the resulting pollutants, environmental issues, ongoing legal requirements and cleaner production strategies. In Iran, the pulp and paper industry's technological development is not keeping pace with global growth. Iran's pulp and paper mills supply a small fraction of domestic market. The reasons can be due to old technologies being used in factories, aging machinery, low productivity of production systems and lack of coordination with modern technologies. It leads to low-quality of paper products and willingness to buy local products. The aim of this study is to select the most appropriate technologies in the pulp section, due to high impact of pulp quality on the quality of final paper. Using a 2-filterd fuzzy decision-making, hierarchical structure of research is designed to assess technological alternatives according to the selected criteria. Findings show that after passing through two filters, Kraft method was chosen as the most appropriate method. The Kraft process has still many advantages like the high quality of the produced pulp and self-sufficiency in energy supply. This framework offers an appropriate procedure for identifying and selecting technologies that has not been used in past researches. Using this framework facilitates using a clear procedure for evaluating and selecting technology and prevents future losses for organizations.

Study on the quantitative measurement of firmness distribution maps at the pixel level inside peach pulp

Firmness is a major quality index for peaches and many other fruits. Because firmness varies among different parts of the pulp, maps of the firmness distribution inside peach pulp can be used as an important indicator for deeply understanding and evaluating the ripening process of fruit and for further optimizing planting patterns and postharvest storage strategies. However, the commonly used Magness-Taylor firmness tester cannot provide the firmness distribution at the pixel level, because it measures only one or a few sampling points where the probe is located. In this study, a laboratory-based hyperspectral imaging system in the wavelength range of 380–1030nm was developed to detect and visualize the firmness distributions for different cross sections of peach pulp. Two calibration methods based on partial least squares regression (PLSR) and least squares support vector machines were applied to establish firmness calibration models. In addition, the successive projections algorithm, uninformative variable elimination, and competitive adaptive reweighted sampling (CARS) were applied separately to select the optimal wavelengths to improve the models’ accuracy and robustness. CARS-PLSR without preprocessing was determined to be the best model for determining the firmness of peach pulp, yielding prediction results with a correlation coefficient of 0.852 and a residual predictive deviation of 1.739. Using this model, the firmness distributions for different cross sections of peach pulp were quantitatively visualized at the pixel level. The firmness histogram revealed the existence of a wide range of firmnesses inside peach pulp. The overall results demonstrated that hyperspectral imaging shows great potential for visualizing the spatial variations in the firmness distribution inside peach pulp at the pixel level, which can provide a more detailed understanding of the ripening process of peach fruits during the preharvest and postharvest periods.

Enzymes, dentinogenesis and dental caries: a literature review.

ABSTRACTObjectivesSearch in PubMed with keywords “enzymes, dentinogenesis, and dental caries” revealed only 4 items, but when combined with “enzymes, osteogenesis, and osteoporosis” as high as 404 items resulted. Dental caries was associated with an order of magnitude fewer studies than the chronic bone disease, osteoporosis. This observation motivated this review.Material and MethodsA comprehensive review of the available literature on role of enzymes in dentinogenesis and dental caries was undertaken using MEDLINE (PubMed) and Scopus. Keywords for the search were: enzymes and odontoblasts, enzymes and different forms of dentinogenesis as well as dental caries.ResultsSearch revealed studies which described odontoblasts harbouring numerous enzymes (hydrolases, including metalloproteinases, transaminases and dehydrogenases) during primary dentinogenesis. Alkaline phosphatase activity sharply decreased when odontoblasts turned into quiescent odontoblasts. Tertiary dentinogenesis was characterized first by reactionary dentine formation when alkaline phosphatase was highly reactivated. Then later some of these odontoblasts may die out and be replaced by other progenitor cells of pulpal origin. This tertiary dentine was called reparative dentine. Pulpal progenitor/stem cells revealed alkaline phosphatase activity in areas encircling inflamed pulp sections. Soft carious dentine revealed high hydrolase, transaminase and dehyrogenase activities that may have originated from invading microbes, saliva or were endogenous. Proteolytic activity was especially demonstrable using histochemical and biochemical means. Specifically, matrix metalloproteases may have originated partly from activated proenzymes of host origin.ConclusionsThough dental studies are scanty when compared to bone, the active role of large spectrum of enzymes in healthy and carious dentine was given support.

A Case Study to Assess the Sample Preparation Error in Pesticide Residue Analysis

In the scope of this study, pesticide residue distribution within a fruit and the possible error deriving from sample preparation step were demonstrated with the analysis of benomyl residues in peel, pulp, and seeds of papaya fruits treated post-harvest. Benomyl residue, measured as carbendazim, in corresponding sections of peel and pulp of papaya fruits ranged from 0.178 to 1.325 mg/kg and 0.025 to 0.087 mg/kg, respectively. Residue concentration decreased in a range between 41 and 83 % by peeling of papaya. All seeds contained residue value below limit of quantification. As the residues are unevenly distributed among the peel, pulp, and seed, pesticide residue analysis should be carried out accurately according to proper sample preparation protocol in peel, pulp, or in whole fruit and evaluated correctly taking into consideration the purpose of the analysis. The proportion of peel and pulp after their separation significantly affected the residues measured in the peel and pulp. It shows how peeling operation can affect the results and how important it is to remove the peel without significant portion of pulp attached to it. Thus, the selected test system could be well used to demonstrate the possible variability of measured residues depending on the uniformity of sample preparation.

Pulpal status of human primary molars with coexisting caries and physiological root resorption

This study sought to investigate the effect of caries, in association with physiological root resorption, on the pulpal status of human primary molars. Fifty-three mandibular primary molars were obtained from children requiring extractions under general anaesthesia. Following extraction, teeth were split longitudinally and placed in Zamboni's fixative. Teeth were categorised according to i) the depth of caries (less than or greater than halfway through dentine thickness) and ii) the degree of physiological root resorption (<33%, 34-66% or >67% of the root length). Ten-micrometre pulp sections were subject to indirect immunofluorescence using a combination of PGP 9.5 (a general neuronal marker), CD45 (a general neuronal marker), and Ulex europaeus agglutinin I (a marker of vascular endothelium). Image analysis was used to determine the percentage area of staining (PAS) for innervation and immune cells. Marked differences were seen between different samples, but there were no significant differences in mean PAS for PGP 9.5 or CD45 according to the degree of caries or extent of physiological root resorption (two-way anova, P > 0.05). Findings suggest that even if primary molars are undergoing exfoliation, they show comparable caries-induced changes to teeth without physiological root resorption, thus retaining potential for healing and repair.

Pulp Progenitor Cell Recruitment is Selectively Guided by a C5a Gradient

It recently became evident that activation of the complement system also contributes to tissue regeneration after infection/injury. The complement-derived fragment C5a induces vascular modifications and attracts cells expressing its receptor (C5aR/CD88) to the site of infection and tissue injury. Besides inflammatory cells, various tissue cells express this receptor. We hypothesized that pulp progenitor cells, being exposed to local complement activation in caries lesions, may respond to C5a via the C5aR. Our work aimed at evaluating the ability of C5a to induce pulp progenitor cell migration that may link complement activation to dentin regeneration. Immunofluorescence analysis of third molar pulp sections showed perivascular localization of the mesenchymal stem cell markers STRO-1 and C5aR. RT-PCR on STRO-1-sorted pulp progenitor cells, co-expressing both STRO-1 and C5aR, revealed high C5aR mRNA levels. Experiments with the C5aR antagonist W54011 revealed that C5a specifically bound to progenitor cells via C5aR, inducing their selective migration toward the C5a gradient. Since we could also demonstrate C5b-9 formation by immunohistochemistry in carious teeth, our findings suggest that, upon local complement activation, C5a induces pulp progenitor cell migration, which may be critical in initiating the regenerative process after dentin/pulp injury.

Quantitative Ultrastructural Analysis of the Neurofilament 200–Positive Axons in the Rat Dental Pulp

Introduction Previous studies have suggested that myelinated axons lose their myelin and become thinner in their peripheral course to the target organ. In this study, we investigated the morphologic changes of pulpal myelinated axons between their root portion (radicular pulp) and their terminal area (peripheral pulp). Methods Sections of pulp of the rat upper molar teeth were immunostained for the marker of myelinated axons neurofilament (NF) 200. The proportion of NF200+ myelinated and unmyelinated fibers and their sizes were analyzed by using quantitative electron microscopy. Results The axon area, myelin thickness, and fraction of NF200+ myelinated axons of all NF200+ axons were significantly lower in peripheral than in radicular pulp. In addition, large unmyelinated axons were frequently observed in peripheral pulp. Conclusions These results suggest that pulpal innervation originates predominantly from myelinated axons, and the myelinated axons undergo extensive morphologic changes during their course from the radicular to the peripheral pulp.

Pulpal status of human primary teeth with physiological root resorption

The overall aim of this study was to determine whether any changes occur in the pulpal structure of human primary teeth in association with physiological root resorption. The experimental material comprised 64 sound primary molars, obtained from children requiring routine dental extractions under general anaesthesia. Pulp sections were processed for indirect immunofluorescence using combinations of: (i) protein gene product 9.5 (a general neuronal marker); (ii) leucocyte common antigen CD45 (a general immune cell marker); and (iii) Ulex europaeus I lectin (a marker of vascular endothelium). Image analysis was then used to determine the percentage area of staining for each label within both the pulp horn and mid-coronal region. Following measurement of the greatest degree of root resorption in each sample, teeth were subdivided into three groups: those with physiological resorption involving less than one-third, one-third to two-thirds, and more than two-thirds of their root length. Wide variation was evident between different tooth samples with some resorbed teeth showing marked changes in pulpal histology. Decreased innervation density, increased immune cell accumulation, and increased vascularity were evident in some teeth with advanced root resorption. Analysis of pooled data, however, did not reveal any significant differences in mean percentage area of staining for any of these variables according to the three root resorption subgroups (P > 0.05, analysis of variance on transformed data). This investigation has revealed some changes in pulpal status of human primary teeth with physiological root resorption. These were not, however, as profound as one may have anticipated. It is therefore speculated that teeth could retain the potential for sensation, healing, and repair until advanced stages of root resorption.

Co-Expression of Cyclooxygenase-2 and Vascular Endothelial Growth Factor in Inflamed Human Pulp: An Immunohistochemical Study

Recent data from the medical literature indicates that cyclooxygenase-2 (COX-2) plays a key role in the production of vascular endothelial growth factor (VEGF), a glycoprotein that has the ability to increase the permeability of blood vessels and to induce angiogenesis. This study was undertaken to investigate the immunohistological co-expression of COX-2 and VEGF in inflamed human pulp, in conjunction with the expression of CD34, a transmembrane glycoprotein expressed in endothelial cells. Pulp tissue of extracted carious human third molars with a recent history of spontaneous pain were collected and processed for immunostaining of COX-2, VEGF, and CD34 using the biotin-streptoavidin method. Healthy pulp samples served as controls. COX-2 expression was not observed in healthy pulps, whereas all inflamed pulps demonstrated COX-2-expressing cells. Similarly, VEGF was not expressed in normal pulp tissue, but was strongly positive in inflamed pulps. CD34 was expressed in the endothelium of both normal and inflamed pulp tissues. Co-expression of COX-2 and VEGF in all consecutive sections of inflamed pulps could be suggestive of a possible release of VEGF via a COX-2-dependent pathway.

The microstructure and tannin content of banana fruit and their likely influence on juice extraction

AbstractExtraction of banana juice using the traditional physical method is limited to Mbidde banana cultivars. Most other banana cultivars (including Matooke cultivars) do not produce juice by this method. A study of the microstructure and tannin content of banana fruit (Mbidde and Matooke cultivars) was carried out in order to understand the underlying factors in the juice extraction process and develop a working hypothesis to explain the mechanism of juice separation. Microscopic examination of pulp sections of Mbidde bananas revealed that their microstructure contained many more intensely stained and larger laticifer cells than pulp tissues of Matooke cultivars. On ripening, the intensity of staining of laticifer cells in Mbidde fruit appeared to increase, while there was limited or no staining in fruit of Matooke cultivars. There was also higher tannin content in Mbidde than in Matooke bananas at both unripe and ripe stages. The high tannin concentration corresponding to the unique presence of high numbers of laticifer cells in fruit of Mbidde cultivars suggests that the ability of the bananas to release juice is linked to tannins. During juice extraction the physical working of the banana pulp ruptures the laticifer cells, resulting in the release of tannins that interact with celluloses, hemicelluloses, proteins and, most importantly, pectins to form insoluble complexes, thus facilitating juice release. Copyright © 2006 Society of Chemical Industry