Substantivity of zinc salts used as rinsing solutions and their effect on the inhibition of Streptococcus mutans

The antimicrobial efficacy of zinc (Zn) salts (sulfate and acetate) against Streptococcus mutans (S. mutans) present in the oral cavity was tested in this study. The substantivity of Zn salts was assessed by determining the concentration of Zn in whole, unstimulated saliva and by measuring the magnitude of suppression of salivary S. mutans, 2h after rinsing. The concentration of Zn was measured by atomic absorption spectrometry (AAS) with electrothermal atomization (ET AAS) in saliva sampled before (basal) and 24h after mouth rinsing with different concentrations of Zn (0.1%, 0.5% and 1%) administrated as sulfate and acetate. The estimation of Zn levels in samples collected 30, 60, 90 and 120 min after rinsing was carried out by AAS with flame atomization (FAAS). Immediately after rinsing, the concentration of Zn in saliva sharply increased with respect to the baseline values (0.055+/-0.017 mg/L), followed by a sustained decrease, probably due to clearance of salivary flow or swallowing during sampling. A significant reduction (>87%) in the total mean S. mutans counts was found 2h after rinsing either with sulfate or acetate solutions, as evidence of the high substantivity and effectiveness of the Zn salts tested. A statistically significant inverse relationship (p<0.001 and the Pearson correlation coefficients between -34% and -50%) was found between Zn levels and the respective pH values measured in the samples collected 60 and 120 min after rinsing, sustaining the theory of bacterial glycolysis inhibition.     

EFFECTIVENESS OF RINSES IN ALLEVIATING BITTERNESS AND ASTRINGENCY RESIDUALS IN MODEL SOLUTIONS1,2

A two‐part study determined the effectiveness of gum‐based rinses with or without oil for alleviating residuals of a bitter (0.8 g/L caffeine solution) and an astringent (1g/L alum solution) stimuli in serial responses using a sip and spit method. In Experiment 1, rinsing with deionized water was compared to rinsing with 0.3% xanthan gum in water alone or with 5% corn oil and 0.55% carboxymethyl cellulose (CMC) in water alone or with 5% or 10% corn oil. The 0.3% xanthan gum and 5% corn oil mixture resulted in the highest stimulus intensity difference before and after rinsing, whereas 0.55% CMC had a value of nearly zero for residual effect. Results of a two‐alternative forced choice test used in Experiment 2 indicated that both were equally effective for reducing bitterness residuals, but 0.55% CMC solution resulted in the lowest (p=0.007) residual effect for astringency. Therefore, the 0.55% CMC rinse was considered an effective interstimulus rinse to use for assessing both bitterness and astringency in model solutions.     

Effects of sample collection and storage conditions on DNA damage in buccal cells from agricultural workers

Buccal cells are becoming a widely used tissue source for monitoring human exposure to occupational and environmental genotoxicants. A variety of methods exist for collecting buccal cells from the oral cavity, including rinsing with saline, mouthwash, or scraping the oral cavity. Buccal cells are also routinely cryopreserved with dimethyl sulfoxide (DMSO), then examined later for DNA damage by the comet assay. The effects of these different sampling procedures on the integrity of buccal cells for measuring DNA damage are unknown. This study examined the influence of the collection and cryopreservation of buccal cells on cell survival and DNA integrity. In individuals who rinsed with Hank's balanced salt solution (HBSS), the viability of leukocytes (90%) was significantly (p<0.01) greater than that of epithelial cells (12%). Similar survival rates were found for leukocytes (88%) and epithelial cells (10%) after rinsing with Listerine(?) mouthwash. However, the viability of leukocytes after cryopreservation varied significantly (p<0.01) with DMSO concentration. Cell survival was greatest at 5% DMSO. Cryopreservation also influenced the integrity of DNA in the comet assay. Although tail length and tail moment were comparable in fresh or cryopreserved samples, the average head intensity for cryopreserved samples was ～6 units lower (95% CI: 0.8-12 units lower) than for fresh samples (t(25)=-2.36, p=0.026). These studies suggest that the collection and storage of buccal samples are critical factors for the assessment of DNA damage. Moreover, leukocytes appear to be a more reliable source of human tissue for assessing DNA damage and possibly other biochemical changes.     

The mycoflora of the subhuman primates

Summary Culture studies revealed that 54.3 % of 70 mouth samples and 15.1 % of 371 throat samples from captive male and female baboons contained yeasts.Candida albicans was found to be the highest single species isolated from the oral cavity of both sexes, with the exception ofTrichosporon, which was slightly higher in the mouths of female baboons.There is a slight indication that the yeast flora of the female oral cavity is higher than that of the male. Similarly, there is a close parallelism between the oral mycoflora of human beings and that of the baboons studied.     

EFFECTIVENESS OF PALATE CLEANSERS FOR EVALUATING SOURNESS

The objective of this study was to compare four palate cleansing strategies (crackers, carrots, water and nothing) for their effectiveness in evaluating the sourness of a fruit-flavored beverage. Forty panelists rated the sourness intensity of five orange drink samples that varied in citric acid content. Each subject participated in four sessions, one for each palate cleanser. As expected, sourness increased with increasing citric acid content. There were no significant differences between any of the palate cleansers for the discrimination among the sourness levels. Sourness neither increased (buildup) nor decreased (adaptation) during the session with any of the palate cleansing strategies. Using carrots or water provided similar discrimination to crackers, but the panelists rated the sourness higher after using carrots or water as a palate cleanser than after using the cracker.

PRACTICAL APPLICATIONS

Palate cleansers are widely used during sensory evaluation of foods. We suspect that part of the reason people use them is because they lower the intensity of residual flavors, leading people to believe the flavors have been removed from their mouth. Our results show that residual cleansers can produce changes in the flavor of subsequently tasted products. Because the nature and extent of these changes will logically depend on the specific product and the specific palate cleansing strategy, experiments need to be conducted to provide these measures.     

Self- and cross-desensitization of oral irritation by menthol and cinnamaldehyde (CA) via peripheral interactions at trigeminal sensory neurons

Menthol and cinnamaldehyde (CA) are plant-derived spices commonly used in oral hygiene products, chewing gum, and many other applications. However, little is known regarding their sensory interactions in the oral cavity. We used a human psychophysics approach to investigate the temporal dynamics of oral irritation elicited by sequential application of menthol and/or CA, and ratiometric calcium imaging methods to investigate activation of rat trigeminal ganglion (TG) cells by these agents. Irritancy decreased significantly with sequential oral application of menthol and CA (self-desensitization). Menthol cross-desensitized irritation elicited by CA, and vice versa, over a time course of at least 60 min. Seventeen and 19% of TG cells were activated by menthol and CA, respectively, with ～50% responding to both. TG cells exhibited significant self-desensitization to menthol applied at a 5, but not 10, min interval. They also exhibited significant self-desensitization to CA at 400 but not 200 μM. Menthol cross-desensitized TG cell responses to CA. CA at a concentration of 400 but not 200 μM also cross-desensitized menthol-evoked responses. The results support the argument that the perceived reductions in oral irritancy and cross-interactions between menthol and CA and menthol observed (at least at short interstimulus intervals) can be largely accounted for by the properties of trigeminal sensory neurons innervating the tongue.     

The influence of rinsing routines on fluoride retention after toothbrushing

Objective: An important determinant of the anticaries effect of brushing with a fluoride dentifrice is the retention of fluoride in the oral fluids. This study measured the influence of various post‐brushing rinsing routines on fluoride retention. Setting: The Faculty of Odontology, Göteborg University, Sweden. Subjects: Twenty‐one healthy dental students, aged 23±2 yr. Desing: A randomised, cross‐over protocol, comparing various post‐brushing rinsing procedures, with the following variables: volume of rinsing water (5 mL vs. 10×3mL) and duration of rinsing (10 vs. 60 s). Samples of whole saliva, interdental fluid and interdental plaque were analysed for fluoride content. Results: The duration of rinsing did not influence fluoride retention in whole saliva, interdental fluid or interdental plaque. Rinsing with a higher volume of water substantially decreased fluoride retention in all samples. Conclusion: Brushing with a fluoride dentifrice should be followed by rinsing procedures which enhance the retention of fluoride. Rinsing with large volumes of water decreases fluoride retention in the oral fluids, and should be discouraged.     

Identification of Epstein-Barr virus strain variants in hairy leukoplakia and peripheral blood by use of a heteroduplex tracking assay

Epstein-Barr virus (EBV) strains can be distinguished by specific sequence variations in the LMP1 gene. In this study, a heteroduplex tracking assay (HTA) specific for LMP1 was developed to precisely identify the prototypic undeleted strain B958, other undeleted strains (Ch2, AL, NC, and Med-), and strains with the 30-bp deletion (Med+ and Ch1). This technique also provides an estimate of the relative abundance of strains in patient samples. In this study, EBV strains were identified in 25 hairy leukoplakia (HLP) biopsies and six matched peripheral blood samples and throat washes with the LMP1-HTA. To investigate the relationship of the virus found in the peripheral blood to that in the HLP lesion, the strain variants in the peripheral blood B lymphocytes and those present within the epithelial cells in the HLP lesion and in throat washes were identified. In many of the subjects, compartmental differences in the EBV strain profiles in the oral cavity and peripheral blood were readily apparent. The throat wash specimens usually had a strain profile similar to that within the corresponding HLP sample, which was distinct from the strain profile detected in the peripheral blood. These analyses reveal that the nature of EBV infection can be very dynamic, with changes in relative strain abundance over time as well as the appearance of new strains. The patterns of abundance in the blood and oral cavity provide evidence for compartmentalization and for the transmission of strains between the blood and oropharynx.     

The correlation between the number of polymorphonuclear leukocytes in human oral cavity and the counts of some bacteria

The aim of the study was to evaluate the relationship between the number of polymorphonuclear leukocytes (PMNL) and the number of selected bacteria in human oral cavity. Sixty one healthy people (periodontal index of Russel's did not exceed 0.2), aged 22-26 were investigated. PMNL were isolated by rinsing oral cavity with isotonic, buffered NaCl solution. Nonstimulated whole saliva was bacteriologically examined. The number of PMNL, which was obtained from mouth of examined people was between 100,000 and 4,200,000 in 100 mL of rinsings. Usually, i.e. in 34% of cases, the number was between 500,000-1,000,000. Streptococci were isolated from all tested people and their number was the biggest. Almost in all cases there were isolated cariogenic bacteria--Streptococcus mutans (95%) and lactobacilli (93%). Haemophili, staphylococci, including Staphylococcus aureus, were found relatively often (in 86%, 86% and 52% respectively). Gram-negative enteric rods were rarely isolated (33%) and were the least numerous group of all. It has been stated, that there is a comparatively strong negative correlation between the number of PMNL in oral cavity and the number of streptococci (r=-0.55; p<0.0001), haemophili (r=-0.564; p<0.0001), staphylococci (r=-0.538; p<0.0001), lactobacilli (r=-0.407; p=0.0017) and Streptococcus mutans (r=-0.483; p=0.0002). The results suggest that PMNL are one of the factors controlling the number of some bacteria in human oral cavity.     

Effects of ozone nano-bubble water on mucositis induced by cancer chemotherapy

No effective, reliable treatment for stomatitis associated with cancer therapy has been established. This study focused on the its effectiveness of ozone nano-bubble water (ONBW) for the treatment of chemotherapy-induced stomatitis. Oral mucositis was induced in 14-week-old male Sprague-Dawley rats (N = 21). The animals were randomly divided into 3 groups: 7 without treatment (control); 7 treated with physiological salt solution (saline); and 7 treated with ONBW. Animals were weighed on Days 7, 9, 11, and 16. Stomatitis grade evaluation and bacterial count measurements were performed before rinsing in all animals 3, 5, and 10 days after acetic acid irritation (Days 9, 11, and 17 respectively). Weight loss after stomatitis creation was observed in all groups, with significant differences between the control and ONBW groups and between the saline and ONBW groups on Day 16. The stomatitis grade did not worsen during the experimental period in any group, with the lowest grades in the ONBW group on Days 11 and 16. Significant differences were identified between the control and ONBW groups and between the saline and ONBW groups on Days 11 and 16. Oral bacterial counts tended to decrease over time in all three groups, with the greatest decrease in the ONBW group, followed by the saline group. The decrease in the bacterial count was steepest in the ONBW group. Rinsing out the oral cavity with ONBW decreased bacterial counts and encouraged the healing of oral chemotherapy-induced stomatitis. ONBW may be an effective treatment for chemotherapy-induced stomatitis.     

TASTE DISCRIMINATION BY THE 3-AFC METHOD: TESTING SENSITIVITY PREDICTIONS REGARDING PARTICULAR TASTING SEQUENCES BASED ON THE SEQUENTIAL SENSITIVITY ANALYSIS MODEL

3-AFC discrimination tests between'threshold'concentration NaCl solutions and purified water stimuli were performed using a variety of interstimulus rinsing regimes to test predictions of test sensitivity based on the Sequential Sensitivity Analysis model. Superior performance on triads with NaCl as the'odd'stimulus, over triads with water as the'odd'stimulus, confirmed earlier research. It was possible, using SSA predictions, to find the right combination of rinses, to arrange for either set of triads to elicit strongly superior performance from judges. This manipulation was predicted by SSA but not by an unequal variance Thurstonian model. Failure of some SSA predictions highlighted the notion of stimulus enhancement by adaptation, leading to a modification of the model. Such manipulation of interstimulus rinses could form the basis for increasing or decreasing test sensitivity.     

Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation

Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6 g/kg by oral gavage. In parallel experiments, free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 h. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 h. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive glial fibrillary acidic protein-positive astrocytes and activated CD11b-positive microglia by 40-50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of choline acetyltransferase (ChAT)-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model.     

种植盐地碱蓬改良滨海盐渍土对土壤微生物区系的影响

利用盐生植物盐地碱蓬对天津河口滨海盐碱地进行生物修复,研究了其对土壤微生物区系的影响.结果表明,种植区碱蓬根系土壤的可溶性盐分与对照土壤相比下降了41%（重量法）和37%（电导法）;根系土壤的微生物数量明显增加,其中细菌、放线菌和真菌分别较对照增加了2.3倍、4.3倍和71倍,与对照相比均为显著性差异.根系微生物的耐盐性结果显示,随着土壤盐分的降低,根系微生物生长的最适盐度也随之降低,耐盐性较低的微生物种群已逐渐成为优势种群.系统发育分析表明,枯草杆菌属成为植物修复后土壤中的优势种群.     

Bacteria in the oral mucosa and its effects on the measurement of cortisol, dehydroepiandrosterone, and testosterone in saliva

Bacteria load in saliva was experimentally manipulated, and the consequences for the measurement of salivary testosterone (T), dehydroepiandrosterone (DHEA), and cortisol (C) were examined. Healthy adults (n = 19) donated the first saliva sample upon rising after which they rinsed their mouths with water, waited 10 min, and donated a second sample. Samples were either left untreated or passed through a 0.22-microm filter and then frozen at -80 degrees C or incubated at room temperature (RT) for 10 days. Aliquots of each sample were cultured on agar to determine baseline and post-incubation (or freezing) bacteria load. Bacteria counts were not significantly influenced by rinsing (with water), were substantially reduced by filtration, and increased by incubation at RT. Average levels of salivary T and C, but not DHEA, were significantly lower in samples stored at RT than samples frozen the day of collection. The change in bacteria count induced by storing samples at RT was associated with a change in testosterone but not cortisol or DHEA. When samples were passed through a 0.22-microm filter bacteria counts were reduced, and the association between bacteria and testosterone was reduced to non-significant. These findings contribute to a growing body of literature revealing that the process of sample collection, storage, and handling can dramatically influence the accuracy of information generated when salivary biomarkers are integrated into research and clinical diagnostics.     

运动后补充肉碱可提升骨骼肌糖原合成代谢

本研究旨在探讨单次口服肉碱是否有利于促进人体运动后骨骼肌糖原恢复。本研究为交叉实验设计,选取20名受试者,随机分为肉碱试验(实验组)和安慰剂试验(安慰剂组),两次实验间隔至少7 d。所有受试者接受单次60 min 70%VO_2max功率车测试,运动后立即给予高碳水化合物饮食补充和肉碱胶囊或安慰剂淀粉胶囊口服补充,同时观察运动后3 h恢复期内的生理反应。功率车运动后第0、第3小时从股外侧肌采集肌肉样本,同期间隔每30 min收集血液样本,每60 min收集10 min气体样本。研究发现,实验组肌糖原含量增加率显著增加,在血液生化值方面,两组的血糖浓度在各时间点均无显著差异,但实验组的胰岛素反应显著低于安慰剂组。同时在运动恢复期间,实验组呼吸交换率明显低于安慰剂组,这代表运动恢复期口服肉碱后,身体以脂肪为主要能量来源。研究表明,运动后立即补充肉碱能显著提升人体运动后肌糖原恢复,具备临床进一步推广应用的价值。     

Light interference and melatonin affects digestion and glucocorticoid metabolites in striped mouse

Animals secrete glucocorticoids to deal with daily stressors. Studies have found that supplemental melatonin decreases glucocorticoid metabolite levels in stressed animals. We determined the effect of light interference (LI) and supplemental melatonin on (1) body mass, (2) food intake and (3) glucocorticoid metabolite levels of the striped mouse (Rhabdomys pumilio). Experiment was split into three phases: 8 L: 16 D; 8 L: 16 D with a 15 min light interruption every 4 h; and 8 L: 16 D with a 15 min light interruption every 4 h and melatonin (0.2 μg/ml) added to the water. Body mass was significantly different between phases with lowest body mass (89.17 ± 6.56 g) occurring during standard 8 L: 16 D. LI and melatonin significantly increased body mass. LI increased and melatonin decreased glucocorticoid metabolite levels. LI significantly increased and melatonin significantly decreased assimilation efficiencies possibly due to changes in energetic demands.     

Comamonas acidovorans contamination of dental unit waters

A study was carried out to evaluate the extent of the colonization of dental water systems by Comamonas acidovorans and to investigate how the occurrence of these bacteria is related to certain water characteristics. The 152 water samples were collected from the oral rinsing cup, air-water syringe, turbine and supply lines to dental units. Comamonas acidovorans was found most frequently and in greatest quantities in samples taken from water entering the units and in samples with a lower total bacterial count at 22 degrees C, higher temperature, lower content of organic matter and, in general, higher concentrations of residual chlorine.     

Buffering effect of a prophylactic gel on dental plaque in institutionalised elderly

Objectives: The effect of multiple daily applications of a prophylactic gel, with buffering substances, on plaque acidogenicity in elderly institutionalised individuals was evaluated. Background: Many elderly suffer from reduced salivary flow, poor oral hygiene and increased levels of cariogenic bacteria and are considered to be at an increased risk for coronal and root caries. Reinforcing the buffering capacity of dental plaque by the addition of substances such as bicarbonate and phosphates may decrease their caries activity. Materials and methods: Fourteen elderly, with subjective dry mouth, were treated for 16‐day‐periods at random with: (i) Profylin fluoride gel with buffering components; (ii) Profylin fluoride gel without buffering components and (iii) rinsing with water. Applications were made four times a day and each period was followed by a 2‐week wash‐out period. The plaque pH was registered after a carbohydrate challenge and the following were recorded before and after each test period: stimulated salivary secretion rate, buffer capacity, number Colony Farming Units (CFU) mutans streptococci, lactobacilli and a sample of Candida albicans on oral mucosa. Results: Eleven participants (mean age 76.6 years) fulfilled the study. Changes in plaque pH measurements, when calculated as area under the curve (AUC_6.2 and AUC_5.7) values (pH × min), before and after each of the three treatments, showed no significant differences. A tendency to a higher plaque acidogenicity and amount of cariogenic microorganisms was found after the gel treatments. C. albicans was found in low levels. Conclusion: Frequent applications of the gel did not result in an improved neutralising effect in the elderly. This may be caused by a combination of several factors, such as the level of oral dryness of the individuals and low solubility, release and retention of the gel substances in plaque. Instead, an increased plaque acidogenicity was noted.