Influence of Isolation Temperature on Isolating Diverse Lactic Acid Bacteria from Kimchi and Cultural Characteristics of Psychrotrophs

Kimchi is a traditional Korean fermented vegetable that is stored and fermented at low temperatures. However, kimchi lactic acid bacteria (LAB) are typically isolated under mesophilic conditions, which may be inappropriate for isolating the diverse LAB. Therefore, this study investigated the suitable conditions for isolating various LAB from kimchi. Here, LAB were isolated from four kimchi samples using MRS, PES, and LBS media and varying isolation temperatures (30, 20, 10, and 5°C). Then, MRS was selected as the suitable medium for LAB isolation. A comparison of culture-dependent and culture-independent approaches indicated that 5°C was not a suitable isolation temperature. Thus, the number and diversity of LAB were determined at 30, 20, and 10°C using 12 additional kimchi samples to elucidate the effect of isolation temperature. With the exception of two samples, most samples did not substantially differ in LAB number. However, Leuconostoc gelidum, Leuconostoc gasicomitatum, Leuconostoc inhae, Dellaglioa algida, Companilactobacillus kimchiensis, Leuconostoc miyukkimchii, Leuconostoc holzapfelii, and Leuconostoc carnosum were isolated only at 10 and 20°C. The growth curves of these isolates, except Leu. holzapfelii and Leu. carnosum, showed poor growth at 30°C. This confirmed their psychrotrophic characteristics. In Weissella koreensis, which was isolated at all isolation temperatures, there was a difference in the fatty acid composition of membranes between strains that could grow well at 30°C and those that could not. These findings can contribute to the isolation of more diverse psychrotrophic strains that were not well isolated under mesophilic temperatures.

Effects of duck fat and κ-carrageenan as replacements for beef fat and pork backfat in frankfurters (R)

Objective

Frankfurters are emulsion-type sausages that are widely consumed worldwide. However, some concerns regarding negative health effects have been raised because of the high fat content and the type of fat. This study aimed to evaluate the effects of duck fat and κ-carrageenan as replacements for beef fat and pork backfat in frankfurters.

Methods

The different formulations for the frankfurters were as follows: 20% beef fat (BF), 20% pork backfat (PBF), 20% duck fat (DF), 20% soybean oil (SO), 20% duck fat/1% κ-carrageenan (DFC), and 20% soybean oil/1% κ-carrageenan (SOC). Physicochemical (fatty acid profile, color, rheological properties, cooking loss, water holding capacity, emulsion stability, and texture profile analysis), oxidative stability and sensory properties of frankfurters were evaluated.

Results

Duck fat and κ-carrageenan improved rheological properties of meat batter, and physicochemical properties (emulsion stability, cooking loss, and hardness) of frankfurters. Moreover, duck fat added-frankfurters (DF and DFC) had higher oxidative stability than that of soybean-added frankfurters (SO and SOC) during refrigerated storage for 28 days. In sensory evaluation, flavor, texture, and overall acceptability of DFC were acceptable to untrained panelists.

Conclusion

Our data suggest that duck fat and κ-carrageenan can replace beef fat and pork backfat in frankfurters. Duck fat and κ-carrageenan contributed to improve the physicochemical properties and oxidative stability while maintaining sensory properties. Therefore, the use of duck fat and κ-carrageenan may be a suitable alternative for replacing beef fat or pork backfat in frankfurters.

Biological activity and processing technologies of edible insects: a review

The burgeoning global population growth has raised concerns regarding the expected increase in the demand for food, which could be partially tackled by identifying novel food sources. To this end, edible insects have recently attracted research interest. Several technologies for utilizing edible insect-derived proteins have been introduced; however, research into their functional utilization is insufficient. Herein, we reviewed the relevant literature on the importance of insects as food sources, extraction of edible insects, the nutritional value of insects, biological activities of components, and their applications in food industries. We summarized the studies primarily focused on the functional utilization of edible insects, suggesting that for successful incorporation and growth of edible insects in food and pharmaceutical industries, strategies to improve the extraction methods are required to explore the biological activity of edible insects. Furthermore, the awareness of edible insects with a focus on their allergens warrants consideration.

In Vitro and In Vivo Study on the Toxic Effects of Propiconazole Fungicide in the Pathogenesis of Liver Fibrosis

Propiconazole (PCZ) is a hepatotoxic triazole fungicide. There are insufficient data on how PCZ induces liver fibrosis in humans. This study aimed to investigate the effect of PCZ on liver fibrosis and its underlying mechanisms. HepG2 cells and Sprague-Dawley rats were exposed to PCZ at doses of 0-160 μM (3-72 h) and 0.5-50 mg/kg body weight/day (28 days), respectively. PCZ-treated cells activated intracellular oxidative stress via cytochrome P450 and had higher mRNA levels of interleukin-1β, tumor necrosis factor-α, matrix metalloproteinase (MMP)-2, MMP-9, and transforming growth factor-β (TGF-β) than the control. PCZ treatment in cells induced a morphological transition with E-cadherin decrease and vimentin and Snail increase via the oxidative stress and TGF-β/Smad pathways. PCZ administration in rats induced liver fibrosis through pathological changes, epithelial-mesenchymal transition, and collagen deposition. Thus, our data suggest that exposure of PCZ to humans may be a risk factor for the functional integrity of the liver.

Physicochemical properties and oxidative stability of duck fat-added margarine for reducing the use of fully hydrogenated soybean oil

Soybean oil (SBO) and fully hydrogenated soybean oil (FHSBO) have been used for margarine production. However, SBO-based margarine requires a considerable amount of trans fatty acid-containing FHSBO due to its low melting point. We aimed to reduce the FHSBO content in margarine by employing duck fat, which has a higher melting point than SBO. Margarines were prepared using different ratios of duck fat and reduced levels of SBO and FHSBO. Physicochemical, sensory, and oxidative properties of the margarines were evaluated. The quality characteristics of margarine improved when duck fat replaced SBO and FHSBO. Furthermore, the lipid oxidation parameters were lower in duck fat-added margarines than the control during storage at 60 °C for 28 days. The margarine containing 80% duck fat showed the best sensory properties. Collectively, duck fat can replace SBO in margarine while reducing the use of FHSBO and maintaining desirable physicochemical properties, oxidative stability, and sensory properties.

Quality characteristics of yogurts fermented with short-chain fatty acid-producing probiotics and their effects on mucin production and probiotic adhesion onto human colon epithelial cells

Probiotics can ferment nondigestible carbohydrates and produce short-chain fatty acids (SCFA; acetate, propionate, and butyrate) in the human colon. In this study, the levels of SCFA were determined in the following yogurts fermented with different combinations of probiotics: (1) cocultures of Streptococcus thermophilus and Lactobacillus bulgaricus (control, C); (2) S. thermophilus, L. bulgaricus, and Bifidobacterium bifidum (C-Bb); (3) S. thermophilus, L. bulgaricus, and Lactobacillus acidophilus (C-La); and (4) S. thermophilus, L. bulgaricus, and Lactobacillus gasseri (C-Lg). Results showed that the acetate levels were significantly higher in C-Bb, C-La, and C-Lg yogurts than in C yogurt. Fermentation and physicochemical characteristics of all yogurts were identical. Treatment of mucus-secreting colon epithelial cells (HT29-MTX) with C-Bb, C-La, and C-Lg yogurt supernatants resulted in an increase in the expression of MUC2 and CDX2 and the production of mucin proteins. The adhesion of probiotics onto HT29-MTX cells increased following treatment with C-Bb, C-La, and C-Lg yogurt supernatants. Our data suggest that a yogurt diet rich in acetate improves the protective function of the intestinal epithelium.

Evaluation of gels formulated with whey proteins and sodium dodecyl sulfate as a fat replacer in low-fat sausage

Consumers are increasingly interested in low-fat meat products. Therefore, there is demand for new fat replacers that improve the quality of low-fat meat products. Whey protein isolate (WPI; 10% (w/v)) and sodium dodecyl sulfate (SDS; 0-0.09% (w/v)) were used to produce WPI-SDS gel as a fat replacer of low-fat meat products. Characteristics of WPI-SDS gel were evaluated using SDS-PAGE, FT-IR, viscometer, and texture analyzer. Addition of SDS to WPI increased gelation while reducing aggregation. Addition of 0.06% SDS to WPI-SDS gel has the highest viscosity and hardness, while 0.09% SDS decreased the heat stability of WPI. Quality characteristics including cooking loss, emulsion stability, hardness, and chewiness were significantly improved in WPI-SDS gel-supplemented low-fat sausages. Particularly, the highest hardness and chewiness were obtained in the low-fat sausage added with WPI-SDS gel containing 0.06% SDS. Our results suggest that WPI-SDS gel can be used as a fat replacer in low-fat meat products.

Short communication: Effects of moringa extract on adhesion and invasion of Escherichia coli O55 in bovine mammary epithelial cells

The objective of this study was to evaluate the antibacterial activities of extract derived from moringa leaves. In particular, the effect of moringa extract (Mor) on adhesion and invasion of Escherichia coli O55, Enterococcus faecalis, Staphylococcus simulans, and Serratia liquefaciens was evaluated in bovine mammary epithelial cells (MAC-T). Broth microdilution method, minimum inhibitory concentration and minimum bactericidal concentration assays, adhesion and invasion assays, and real-time PCR were performed. The minimum inhibitory concentration and minimum bactericidal concentration of Mor ranged from 12.5 to 50 mg/mL on 18 out of 27 tested isolates. Treatment of E. coli O55 with Mor (100 and 200 μg/mL) inhibited the adhesion and invasion on MAC-T cells via downregulation of adhesion factors (i.e., papC, f17c-A, and eaeA). Also, when MAC-T cells were pretreated with Mor (200 μg/mL, 12 h) and incubated with E. coli O55, Enterococcus faecalis, Staphylococcus simulans, or Serratia liquefaciens, both E. coli O55 and Enterococcus faecalis showed a significant decrease in adhesion and invasion. Staphylococcus simulans exhibited decreased adhesion and increased invasion. Serratia liquefaciens showed increased adhesion and decreased invasion. In addition, Mor increased mRNA expression of antioxidant enzymes (e.g., heme oxygenase-1, NAD(P)H:quinone oxidoreductase-1, and thioredoxin reductase 1) in MAC-T cells. In conclusion, 12.5 to 50 mg/mL of Mor exhibited antibacterial activity against 18 out of 27 tested isolates. Also, pretreatment of 200 μg/mL of Mor to MAC-T cells modulated adhesion and invasion of E. coli O55 and other mastitis-associated pathogens. Furthermore, Mor increased antioxidant capacities in MAC-T cells, but further in vivo studies are needed.

Aluminum exposure promotes the metastatic proclivity of human colorectal cancer cells through matrix metalloproteinases and the TGF-β/Smad signaling pathway

Human exposure to aluminum (Al) mainly occurs through food intake. However, influences of Al on the gastrointestinal tract have been rarely reported. In particular, the effect of Al on the metastasis and angiogenesis of colorectal cancer cells has not been studied. Thus, we investigated the effect of Al on the metastatic proclivity using the human colorectal cancer cell line, HT-29. Cells were exposed to 1-16 mM AlCl₃ for 3-72 h. The effects of AlCl₃ on HT-29 cells for migration/invasion/adhesion, and metastasis-associated protein and gene expression were evaluated. AlCl₃ promoted cell migration and invasion, whereas it suppressed cell adhesion. AlCl₃-exposed cells showed decreased E-cadherin and increased vimentin and Snail. AlCl₃ increased transforming growth factor-beta (TGF-β) mRNA expression and Smad2/3 nuclear translocation. AlCl₃-treated cells had a higher mRNA expression of matrix metalloproteinase (MMP)-7 and -9 than the control. Particularly, AlCl₃-treated HT-29 cells promoted the angiogenesis of endothelial cells via increasing the secretion of vascular endothelial growth factor. Taken together, AlCl₃ can promote the metastatic proclivity of colorectal cancer cells through MMP-7, -9, and TGF-β/Smad2/3 pathway. Our data suggest that Al exposure of the gastrointestinal tract may be a risk factor for metastasis initiation in colorectal cancer cells.

Effects of Aluminum on the Integrity of the Intestinal Epithelium: An in Vitro and in Vivo Study

BACKGROUND

Aluminum (Al) is the most abundant and ubiquitous metal in the environment. The main route of human exposure to Al is through food and water intake. Although human exposure to Al is common, the influence of Al on the gastrointestinal tract remains poorly understood.

OBJECTIVES

We aimed to further understand the toxic effect of Al and to elucidate the underlying cellular mechanisms in the intestinal barrier.

METHODS

The human intestinal epithelial cell line HT-29 and C57BL6 mice were exposed to AlCl3 at 0-16 mM (1-24h) and 5-50mg/kg body weight (13 weeks), respectively. In cell culture experiments, intracellular oxidative stress, inflammatory protein and gene expression, and intestinal epithelial permeability were measured. In animal studies, histological examination, gene expression, and myeloperoxidase (MPO) activity assays were conducted.

RESULTS

Cellular oxidative stress level (superoxide production) in AlCl3-treated cells (4 mM, 3h) was approximately 38-fold higher than that of the control. Both protein and mRNA expression of tight junction (TJ) components (occludin and claudin-1) in AlCl3-treated cells (1-4 mM, 24h) was significantly lower than that of the control. Transepithelial electrical resistance (TEER) decreased up to 67% in AlCl3-treated cells (2 mM, 24h) compared with that of the control, which decreased approximately 7%. Al activated extracellular signal-regulated kinase 1/2 and nuclear factor-kappa B (NF-κB), resulting in mRNA expression of matrix metalloproteinase-9, myosin light-chain kinase, and inflammatory cytokines [tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and IL-6] in HT-29 cells. Moreover, oral administration of AlCl3 to mice induced pathological alteration, MPO activation, and inflammatory cytokine (TNF-α, IL-1β, and IL-6) production in the colon.

CONCLUSION

Al induced epithelial barrier dysfunction and inflammation via generation of oxidative stress, down-regulation of the TJ proteins, and production of inflammatory cytokines in HT-29 cells. In addition, Al induced toxicity in the colon by increasing the levels of inflammatory cytokines and MPO activity and induced histological damage in a mouse model. Our data suggest that Al may be a potential risk factor for human intestinal diseases. https://doi.org/10.1289/EHP5701.

Zearalenone Induces Endoplasmic Reticulum Stress and Modulates the Expression of Phase I/II Enzymes in Human Liver Cells

Zearalenone (ZEN) is a mycotoxin produced by Fusarium species; however, its mechanisms of action in human livers have not been fully elucidated. Thus, we investigated the toxic mechanisms of ZEN in human liver cells. HepG2 cells were treated with ZEN (0-40 μg/mL) for up to 24 h. A significant decrease in cell viability was observed after treatment with 20 and 40 μg/mL of ZEN, including a significant increase in apoptosis and reactive oxygen species production. ZEN increased GRP78 and CHOP, and eIF2α phosphorylation, indicating ER stress; elevated transcription of the autophagy-associated genes, beclin1 and LC3, and translation of LC3; and increased phase I metabolism by increasing PXR and CYP3A4. The protein expression level of CYP3A4 was higher with ZEN treatment up to 20 μg/mL, but remained at the control level after treatment with 40 μg/mL ZEN. In phase II metabolism, Nrf2 activation and UGT1A expression were increased with ZEN treatment up to 20 μg/mL. Treating cells with an ER stress inhibitor alleviated ZEN-induced cell death and autophagy, and inhibited the expression of phase I/II enzymes. Overall, high ZEN concentrations can modulate the expression of phase I/II enzymes via ER stress and reduced protein levels in human liver cells.

Technical Functional Properties of Water- and Salt-soluble Proteins Extracted from Edible Insects

The amino acid composition, protein quality, and protein functionality of protein solution extracted from three edible insect species were investigated. We used 0.02% ascorbic acid and 0.58 M saline solution to extract water-soluble and salt-soluble proteins from the three insect species. Extracted protein solutions of Tenebrio molitor (TM), Allomyrina dichotoma (AD), and Protaetia brevitarsis seulensis (PB) were divided into six groups, according to species and solubility: WTM, WAD, WPB (water-soluble), and STM, SAD, and SPB (salt-soluble). Defatted TM had the highest protein content, but its protein solubility was the lowest, for both water and saline solutions. Amino acid composition differed by edible insect species and buffer type; SPB had the highest protein quality, followed by WPB. PB had a higher pH than the other species. Color values also differed among species. SPB had abundant high molecular weight proteins, compared with other treatments; and also had the highest foaming capacity, foam stability, and emulsifying capacity. In conclusion, PB is a good source of functional protein compared with the other studied species. Additionally, protein extraction using saline solution is promising as a useful method for improving edible insect protein functionality.

Moringa Extract Attenuates Inflammatory Responses and Increases Gene Expression of Casein in Bovine Mammary Epithelial Cells

Bovine mastitis is a common inflammatory disease in the udder of dairy cows that causes economic loss to dairy industries. The development of alternative strategies, especially the utilization of natural products, e.g. Moringa oleifera, has gained a lot of interests. The objective of the current study was to investigate the protective effects of moringa extract (ME) in bovine mammary epithelial cells (MAC-T) in in vitro settings. Radical scavenging capacities and anti-inflammatory properties of ME were examined using lipopolysaccharide (LPS)-challenged MAC-T cells. ME showed significant radical scavenging activities. In addition, ME decreased reactive oxygen species produced by LPS in cells. ME also attenuated inflammatory cyclooxygenase-2 expression induced by LPS by down-regulating NF-κB signaling cascade. Moreover, ME ameliorated LPS-induced pro-inflammatory cytokines including tumor necrosis factor-, interleukin-1, and interleukin-6. Furthermore, ME up-regulated mRNA expression levels of heme oxygenase-1, NAD(P)H: quinone oxidoreductase-1, and thioredoxin reductase 1. Importantly, ME promoted differentiated MAC-T cells by increasing mRNA expression levels of α-casein S1, α-casein S2, and β-casein. In conclusion, ME has beneficial effects in bovine mammary epithelial cells through its anti-inflammatory, antioxidant, and casein production properties. Our study provides evidence that ME could be a good candidate for a feed supplement to decrease inflammatory responses due to bovine mastitis.

Bee Venom Decreases LPS-Induced Inflammatory Responses in Bovine Mammary Epithelial Cells

The world dairy industry has long been challenged by bovine mastitis, an inflammatory disease, which causes economic loss due to decreased milk production and quality. Attempts have been made to prevent or treat this disease with multiple approaches, primarily through increased abuse of antibiotics, but effective natural solutions remain elusive. Bee venom (BV) contains a variety of peptides (e.g., melittin) and shows multiple bioactivities, including prevention of inflammation. Thus, in the current study, it was hypothesized that BV can reduce inflammation in bovine mammary epithelial cells (MAC-T). To examine the hypothesis, cells were treated with LPS (1 μg/ml) to induce an inflammatory response and the anti-inflammatory effects of BV (2.5 and 5 μg/ml) were investigated. The cellular mechanisms of BV against LPS-induced inflammation were also investigated. Results showed that BV can attenuate expression of an inflammatory protein, COX2, and pro-inflammatory cytokines such as IL-6 and TNF-α. Activation of NF-κB, an inflammatory transcription factor, was significantly downregulated by BV in cells treated with LPS, through dephosphorylation of ERK1/2. Moreover, pretreatment of cells with BV attenuated LPS-induced production of intracellular reactive oxygen species (e.g., superoxide anion). These results support our hypothesis that BV can decrease LPS-induced inflammatory responses in bovine mammary epithelial cells through inhibition of oxidative stress, NF-κB, ERK1/2, and COX-2 signaling.

Green tea powder supplementation enhances fermentation and antioxidant activity of set-type yogurt

Yogurt is a fermented dairy food produced by growth of lactic acid bacteria (LAB). Green tea is associated with beneficial health effects. Thus, the aim of this study was to evaluate the effects of green tea powder (GTP) on the fermentation and bioactive properties of yogurt. Yogurt was supplemented with 0-3% GTP (w/v), and effects on fermentation were determined. In addition, antioxidant and anti-inflammatory effects of GTP supplemented yogurts were determined in HT-29 colon cells. GTP (1-3%) supplementation significantly increased the acidification rate and growth of LAB during yogurt fermentation. Removal of free radicals and cellular H₂O₂, and an increase of antioxidant Nrf2 and HO-1 proteins were observed in the 1-3% GTP groups. Yogurt extracts with 0-3% GTP showed decreased expression of TNF-α and IL-1β in cells. In summary, addition of GTP can enhance the beneficial health effects of yogurt by increasing its antioxidant activity, LAB growth and anti-inflammatory effects.

Piperlongumine decreases cell proliferation and the expression of cell cycle-associated proteins by inhibiting Akt pathway in human lung cancer cells

Piperlongumine (PL) is an alkaloid of a pepper plant found in Southeast Asia. PL is known to induce selective toxicity towards a variety of cancer cell types. To explore the possible anti-lung cancer effects of PL, A549 cells were treated with PL (0-40 μM) for 24 h. Alterations in the expression of cell cycle-associated proteins (cyclin D1, cyclin-dependent kinase 4 (CDK4), CDK6 and retinoblastoma (Rb)) and intracellular signaling molecules (extracellular signal receptor-activated kinase 1/2 (ERK1/2), Akt, p38 and nuclear factor-κB (NF-κB)) were examined in cells following treatment of PL using Western blot analysis. Results showed that proliferation of cells were significantly decreased by PL in a dose-dependent manner. Flow cytometry results demonstrated increased number of cells in G1 phase in PL (40 μM)-treated group. Reactive oxygen species was significantly increased in cells treated with PL at 20-40 μM. The expression of cyclin D1, CDK4, CDK6 and p-Rb were markedly decreased in cells treated with PL at 40 μM. Treatment of cells with PL suppressed phosphorylation of Akt but increased ERK1/2 phosphorylation. Treatment of PL significantly decreased nuclear translocation of NF-κB p65 in cells. These results suggest that PL possesses antiproliferative properties in A549 cells.

Sorption of hydrophobic organic compounds onto organoclays

The behavior and fate of nonionic hydrophobic organic compounds (HOCs) in the environment are mainly controlled by their interactions with various components of soils and sediments. Due to their large surface area and abundance in many soils, smectites may greatly influence the fate and transport of the contaminants in the environment. In our experiments, HOC sorption by hexadecyltrimethylammonium (HDTMA)-modified smectite linearly increased with the amount of HDTMA added to the clay. However, tetramethylammonium (TMA)- and dodecyltrimethylammonium (DTMA)-modified smectites showed not only inferiority in their sorption of HOC compared with the HDTMA-smectite, but also a partially decreased HOC sorption at specific surfactant loading levels. This means that the sorption of organoclays for organic contaminants was significantly influenced by the amount and size of the surfactants added on the clay. In addition, it seems that the interlayer structure (e.g., pore size) formed at each surfactant loading level plays an important role to adsorb HOC in different amount.

Determination of hypoxic region by hypoxia marker in developing mouse embryos in vivo: a possible signal for vessel development

Hypoxia is a well-known signal for angiogenesis, but the recent proposal that hypoxia exists in developing embryonic tissues and that it induces vascular development remains to be proven. In the present study, we demonstrate the presence of hypoxia in normal developing embryos by means of a hypoxia marker, pimonidazole, and its associated antibody. Our data clearly show that hypoxia marker immunoreactivity was highly detected in developing neural tubes, heart, and intersomitic mesenchyme at an early stage of organogenesis, suggesting that hypoxia may exist in the early stages of embryo development. We also found that hypoxia inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) were spatiotemporally co-localized with possible hypoxic regions in embryos. Investigation of platelet endothelial cell adhesion molecule (PECAM) expression provides evidence that endothelial cells proliferate and form the vessels in the hypoxic region in developing organs. Furthermore, we found that hypoxia induced both HIF-1alpha and VEGF in F9 embryonic stem and differentiated cells. Thus, we suggest that hypoxia may exist widely in developing embryonic tissues and that it may act as a signal for embryonic blood vessel formation in vivo.

Mineralogical and hydrochemical effects on adsorption removal of cesium-137 and strontium-90 by kaolinite

Adsorption characteristics of the nuclides onto kaolinite were investigated by batch experiment under various pH conditions and concentrations of groundwater cations (Ca2+, Mg2+, K+ and Na+) and anions (HCO3-, CO3(2-) and SO4(2-). Adsorption removal of 137Cs and 90Sr by kaolinite greatly increased as the concentration of groundwater cations increased from 10(-5) to 10(-1) M. In contrast, the pH exerted a small effect on the adsorption of 137Cs and 90Sr onto kaolinite. The zeta potential of kaolinite particles showed a negative increase of amphoteric surface charge with increasing pH. The adsorption behavior of 90Sr was also highly dependent on the concentration of bicarbonate. The thermodynamic saturation index indicated that bicarbonate exerts great effect on strontium adsorption by the precipitation of a strontianite (SrCO3) and a change in pH.

Effects of topical nasal decongestants on histology of nasal respiratory mucosa in rabbits

The aim of this study was to evaluate histologic changes after long-term administration of the topical nasal decongestants phenylephrine and oxymetazoline. Ninety healthy rabbits were divided into 3 groups for topical administration for 1 week, 2 weeks, and 4 weeks. Each group was subdivided into 3 subgroups by topical administration of phenylephrine. oxymetazoline, and physiologic saline as controls. Each study group thus consisted of 10 rabbits. Phenylephrine was administered by 2 puffs in the left nostril 5 times daily and oxymetazoline by 2 puffs twice a day using metered sprayers giving 0.10 ml in each puff with a dosage used in clinical practice. For statistical significance the Kolmogorov-Smirnov test was used. Light and electron microscopic examination were performed after obtaining nasal respiratory mucosa from the nasal septum of the rabbits. Administration of phenylephrine and oxymetazoline for more than 2 weeks caused histologic changes including ciliary loss, epithelial ulceration, inflammatory cell infiltration and subepithelial edema, and the changes were more pronounced with increasing administration duration of the decongestants. Ciliary loss was prominent in the 4-week phenylephrine and oxymetazoline groups. There were significantly severer changes in the morphologic variables in the decongestant groups compared with the control group according to administration duration (p < 0.05). Dilatation or vacuolization of mitochondria and endoplasmic reticula and vesicles ill the cytoplasm were observed in the 2- and 4-week phenylephrine groups as well as the 2- and 4-week oxymetazoline groups. Mild widening of the intercellular space was observed in the 4-week phenylephrine group. Purulent maxillary sinusitis developed in 6 of 10 rabbits treated for 4 weeks with phenylephrine. The results of this study suggest that the administration of decongestants may cause ciliary loss with subsequent inflammatory changes in the nasal respiratory mucosa.