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Objective Four fluorine-containing borneol ester were synthesized and analyzed for structure characterization and activity.Methods Four fluorine-containing borneol ester derivatives were synthesized by the reaction of fluorinated carboxylic acid and borneol by using p-toluenesulfonic acid as catalyst,and the structures of borneol esters were characterized by 1HNMR and 13CNMR.Molecular docking of the four fluorine-containing borneol ester with P-glycoprotein was carried out by Autodock Vina software.Results Four fluorine-containing borneol ester,bornyl 2-chloro-4-trifluoromethyl benzoate,bornyl 2-chloro-5-fluoro benzoate,bornyl 2-chloro-5-trifluoromethyl benzoate,bornyl 3-trifluoromethyl benzoate,were synthesized.The structures of the borneol ester were confirmed by 1HNMR and 13CNMR.4 fluorine-containing borneol ester had good binding ability with P-glycoprotein.Conclusion Four borneol ester compounds were synthesized,and the borneol ester enriched the types of borneol derivatives,which is of reference value for expanding the application range of borneol.
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Objective:To investigate the relationship between plasma fluoride content, daily calcium intake and blood cell parameters in children and adolescents.Methods:This study was based on the National Health and Nutrition Examination Survey (NHANES) database of the United States from 2013 to 2016, with 3 684 children and adolescents aged 6 - 19 as the research subjects. Information on plasma fluoride content, daily calcium intake and blood cell parameters from the database were collected. Non-linear relationships between plasma fluoride content, daily calcium intake and blood cell parameters were analyzed using restricted cubic splines. If there was a non-linear relationship, the optimal inflection point was calculated using threshold/saturation effect analysis method. Subsequently, multiple linear regression models were used to analyze the associations among the three, and the modification effect of daily calcium intake (binary classification, stratified by median daily calcium intake) on the association between plasma fluoride content and blood cell parameters was analyzed.Results:There was no non-linear relationship between plasma fluoride content and white blood cell count, hemoglobin content and platelet count ( Pnon-linear > 0.05), but there was a non-linear relationship between plasma fluoride content and erythrocyte count and hematocrit ( Pnon-linear < 0.001). After adjusting for confounding factors, the optimal inflection points of the effects of plasma fluoride content on erythrocyte count and hematocrit were 0.54 and 0.31 μmol/L, respectively. There was no non-linear relationship between daily calcium intake and blood cell parameters ( Pnon-linear > 0.05). After adjusting for confounding factors, for every 1 μmol/L increase in plasma fluoride content, the white blood cell count increased by 0.49 × 10 9/L ( P = 0.009). There was a saturation effect in the association between plasma fluoride content, erythrocyte count and hematocrit: when plasma fluoride content was < 0.54 μmol/L, the erythrocyte count decreased by 0.46 × 10 12/L for every 1 μmol/L increase ( P < 0.001). When plasma fluoride content was < 0.31 μmol/L, the hematocrit decreased by 6.29% for every 1 μmol/L increase ( P = 0.006). The above associations were not statistically significant when plasma fluoride content was higher than the optimal inflection points ( P > 0.05). After stratification according to the median daily calcium intake, in the low-calcium group (daily calcium intake < 0.87 g), for every 1 μmol/L increase in plasma fluoride content, the white blood cell count increased by 0.77 × 10 9/L ( P = 0.001). When plasma fluoride content was < 0.54 μmol/L, the erythrocyte count decreased by 0.41 × 10 12/L for every 1 μmol/L increase ( P = 0.002). When plasma fluoride content was ≥0.54 μmol/L, erythrocyte count decreased by 0.47 × 10 12/L for every 1 μmol/L increase ( P < 0.001). When the plasma fluoride content was < 0.31 μmol/L, the hematocrit decreased by 8.29% for every 1 μmol/L increase ( P = 0.011). The above associations were not statistically significant in the high-calcium group (daily calcium intake ≥0.87 g, P > 0.05). There was an interaction of daily calcium intake and plasma fluoride content on platelet count ( Pinteraction = 0.070), as demonstrated by an increase in platelet count of 12.68 × 10 9/L ( P = 0.013) in the low-calcium group and a decrease in platelet count of 9.05 × 10 9/L ( P = 0.035) in the high-calcium group for every 1 μmol/L increase in plasma fluoride content. Conclusions:The blood cell parameters of children and adolescents are closely related to plasma fluoride content, but not directly related to daily calcium intake. However, the correlation between plasma fluoride content and blood cell parameters varies among different calcium intake populations, and daily calcium intake can modify the association between plasma fluoride content and platelet count.
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Objective:To investigate the effect of melatonin (MEL) on learning and memory abilities of fluoride-exposed offspring rats and the role of gut microbiota.Methods:Twelve 8-week-old Sprague-Dawley (SD) rats (8 females and 4 males) with a body weight ranging from 180 to 220 g were selected and divided into control group 1 and fluoride-exposed group 1 using a random number table method, with 6 rats in each group (female ∶ male = 2 ∶ 1). They were free to drink purified water or purified water containing 100 mg/L sodium fluoride, respectively. After 2 months, male and female rats were raised together in cages, and the first postnatal day (PND) of the offspring rats was recorded as PND0. In PND21, the offspring rats of fluoride-exposed group 1 were divided into fluoride-exposed group (Group F, n = 6) and fluoride + MEL group (Group FM, n = 6) using a group design, and continued to be exposed to fluoride through drinking water. The offspring rats of control group 1 were divided into control group (Group C, n = 6) and MEL group ( n = 6). The groups FM and MEL were given 20 mg/kg MEL by gavage, while the groups C and F were given the same dose of normal saline by gavage. In PND60, novel object recognition and Morris water maze tests were used to observe the learning and memory abilities of the offspring rats. Western blotting (WB) was used to detect the expression level of brain derived neurotrophic factor (BDNF) in the hippocampus of the offspring rats. And 16S rDNA sequencing technology was used to detect the changes in the structure and composition of gut microbiota in fecal samples. Results:The results of novel object recognition test showed that there was a statistically significant difference in the discrimination index (DI) among the four groups of offspring rats ( F = 3.95, P = 0.024). The DI in groups C and FM was higher than that of Group F ( P < 0.05). The results of Morris water maze test showed that compared with Group C, the platform-crossing time of the offspring rats of Group F were less and they had a longer time to reach the platform for the first time ( P < 0.05). Compared with Group F, the platform-crossing time of the offspring rats of Group FM were increased and they had a shorter time to reach the platform for the first time ( P < 0.05). The WB results showed that compared with Group C (1.00 ± 0.07), the expression level of BDNF protein in Group F (0.68 ± 0.26) was lower ( P < 0.05). Compared with Group F, the expression level of BDNF protein in Group FM (0.99 ± 0.14) was higher ( P < 0.05). Anosim similarity analysis showed significant differences in the structure and composition of gut microbiota in the four groups of offspring rats ( R = 0.395 062, P = 0.002). The distribution characteristics of gut microbiota species showed that at the phylum level, compared with Group C, the relative abundance of Bacteroidetes in Group F increased from 14.26% to 37.00%, and the relative abundance of Firmicutes decreased from 68.78% to 45.95%. Compared with Group F, the relative abundance of Firmicutes in Group FM increased from 45.95% to 65.26%, and the relative abundance of Bacteroidetes decreased from 37.00% to 23.00%. At the genus level, compared with Group C, the relative abundance of Lactobacillus, Dubosiella, HT002 and UCG-005 in Group F was lower, while the relative abundance of unclassified Muribaculaceae was higher. Compared with Group F, the relative abundance of Lactobacillus, Dubosiella, HT002 and UCG-005 in Group FM was higher, while the relative abundance of unclassified Muribaculaceae was lower. The results of linear discriminant analysis revealed that the Candidatus-Saccharimonas and Incertae-Sedis were significantly enriched in Group C, unclassified Muribaculaceae and Muribaculum were significantly enriched in Group F, and Allorhizobium- Neorhizobium- Pararhizobium- Rhizobium were significantly enriched in Group FM. Conclusion:MEL can improve the learning and memory impairment of offspring rats induced by fluoride exposure by changing the structure and composition of gut microbiota.
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Objective:To study the effects of fluoride on apoptosis and oxidative stress levels of spinal cord nerve cells in rats.Methods:A total of 54 6-week-old Sprague-Dawley female rats, weighing 150 - 200 g, were selected and fed for 1 week. They were divided into a control group [given deionized water containing 0 mg/L sodium fluoride (NaF)], a low fluoride group (given deionized water containing 50 mg/L NaF), and a high fluoride group (given deionized water containing 100 mg/L NaF) using a random number table method, with 18 rats in each group. All groups received standard feed. After 4, 8, and 12 weeks of fluoride exposure, six rats were selected from each group to observe the occurrence of dental fluorosis, and the motor function of hind limbs in rats was evaluated based on the Basso-Beattie-Bresnahan (BBB) score. Then the rats were anesthetized with 5% chloral hydrate via intraperitoneal injection and euthanized by cardiac puncture. Spinal cord tissue of the rats was collected to detect the activities of oxidative stress factors such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as the contents of malondialdehyde (MDA) and catalase (CAT). After 12 weeks of fluoride exposure, morphologic changes in rat spinal cord neurons were observed using Nissl staining, and apoptosis of spinal cord nerve cells was detected using the TdT mediated dUTP nick end labeling (TUNEL) cell apoptosis detection kit. The Western blotting was used to detect the expression of B-lymphoblastoma-2 (Bcl-2) gene related X protein (Bax), Bcl-2 promoter (Bad), and Bcl-2 protein in rat spinal cord tissue; immunofluorescence staining was used to observe the expression of Bax and Bcl-2 protein in spinal cord neurons.Results:After 12 weeks of fluoride exposure, rats in both the low fluoride and high fluoride groups developed varying degrees of dental fluorosis; the differences of BBB scores of rats in the control, low fluoride, and high fluoride groups were statistically significant ( F = 14.09, P < 0.001). The differences of SOD [(124.04 ± 4.87), (96.66 ± 15.01), (91.12 ± 15.87) U/mg prot] and GSH-Px activitives [(561.92 ± 59.65), (456.83 ± 29.51), (385.07 ± 74.87) U/mg prot], MDA [(9.96 ± 1.50), (16.64 ± 2.05), (20.80 ± 3.37) nmol/mg prot] and CAT contents [(8.97 ± 1.05), (6.39 ± 0.97), (6.42 ± 0.83) nmol/mg prot] among the control, low fluoride, and high fluoride groups were statistically significant ( F = 11.17, 14.19, 30.12, 14.52, P < 0.05). Among them, the SOD, GSH-Px activities, and CAT content in the low fluoride and high fluoride groups were lower than those in the control group, while the MDA content was higher than that in the control group ( P < 0.05). The GSH-Px activity in the high fluoride group was lower than that in the low fluoride group, and MDA content was higher than that in the low fluoride group ( P < 0.05). The intact neuronal structures and clear visible nuclei were seen, and Nissl bodies were uniformly stained in the spinal cord neurons of the control group rats, with more numbers, and no apoptotic cells were observed; the staining of Nissl bodies in the spinal cord neurons of rats was uneven in the low fluoride and high fluoride groups, with fewer numbers, and more apoptotic cells. There were statistically significant differences in the apoptosis rate of spinal cord nerve cells and the expression levels of Bax, Bad, and Bcl-2 protein in the spinal cord tissues of rats in the control, low fluoride, and high fluoride groups ( F = 272.81, 35.53, 17.57, 92.50, P < 0.05). The results of immunofluorescence staining showed that there were statistically significant differences in the fluorescent intensity of Bax and Bcl-2 proteins in the spinal cord neurons of rats in the control, low fluoride, and high fluoride groups ( F = 12.67, 22.14, P < 0.05). Conclusion:Chronic fluorosis induces a decrease in antioxidant enzyme activity, an increase in lipid peroxidation levels, and an increase in neuronal apoptosis in the spinal cord of rats.
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Objective:To study the relationship between adult fluoride exposure and grip strength in rural areas of China with fluorosis, as well as the roles of basal metabolic rate (BMR) and body fat percentage (BFP) in the association between fluoride exposure and grip strength.Methods:From April to May 2017, a cluster sampling method was used to conduct a questionnaire survey, physical examination, and biological sample collection on residents aged 18 - 60 in Tongxu County, Kaifeng City, Henan Province (epidemic areas of drinking-water-borne fluorosis). A total of 1 168 subjects were included in the study, including 427 males and 741 females. The fluoride ion selective electrode method and the picric acid method were used to determine the concentrations of urine fluoride and urine creatinine, and the adjusted urine fluoride concentration (CUF) was calculated. BMR and BFP were measured by a bioelectrical impendence method, and the grip strength was measured by a Jamar grip dynamometer. The relationship between CUF, BMR, BFP and grip strength were analyzed using a generalized linear model regression. The mediation effect model was used to assess the mediating effect of BMR and BFP on the association between CUF and grip strength.Results:Female grip strength decreased by 0.28 kg ( P = 0.043) for every 1.00 mg/L increment in CUF. No similar association was found between the two in males ( P = 0.744). Regardless of gender stratification, BMR was positively correlated with grip strength ( P < 0.001). For every 1.00% increase in BFP, female grip strength decreased by 0.18 kg ( P = 0.043). The mediation effect model analysis results showed that the mediation effect ratios of BMR and BFP in the association between CUF and grip strength in female were 65.1% ( P < 0.001) and 8.4% ( P = 0.111), respectively. Conclusion:Fluoride exposure is associated with changes in female grip strength, and BMR changes play a partial mediating role in the association between fluoride exposure and female grip strength.
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Objective:To investigate the distribution of physical and chemical water improvement areas of drinking water-borne endemic fluorosis in Inner Mongolia Autonomous Region, as well as the use of household water purifiers.Methods:From April to October 2021, a survey was conducted in a drinking water-borne endemic fluorosis areas in Inner Mongolia Autonomous Region where physical and chemical water improvement was carried out. The survey included the basic situation of the affected villages (number of permanent households, number of permanent residents, historical water fluoride content) and the use of residential water purifiers. Household peripheral water samples were collected to test the water fluoride content. Water purifier installation rate, normal usage rate, qualified water fluoride rate in normal usage, and the proportion of households covered by filter replacement departments were calculated.Results:In Inner Mongolia Autonomous Region, the physical and chemical water improvement areas of drinking water-borne endemic fluorosis were distributed in 2 735 villages in 11 leagues (cities) throughout the region, with 192 950 permanent households and 540 216 permanent residents. The average historical water fluoride content in all leagues (cities) was 2.18 mg/L, and the current average water fluoride content was 0.40 mg/L. A total of 134 763 water purifiers were installed, with an installation rate of 69.84% (134 763/192 950). A total of 10 773 households were surveyed, with 10 396 households using water purifiers normally and a normal usage rate of 96.50% (10 396/10 773). Among them, 10 158 households had qualified water fluoride of normal usage, with a qualified water fluoride rate of 97.71% (10 158/10 396). Of the 10 396 households using water purifiers normally, 3 974 households (38.23%) had filter cartridges used within one year, and 3 961 households had qualified water fluoride, with a qualified rate of water fluoride of 99.67% (3 961/3 974). Six thousand four hundred and twenty-two households (61.77%) had filter cartridges used for more than one year, with 6 197 households had qualified water fluoride and a qualified rate of water fluoride of 96.50% (6 197/6 422). There was a statistically significant difference in the qualified rate of water fluoride between purifiers with different filter cartridge usage times (χ 2 = 110.73, P < 0.001). Among the 10 773 surveyed households, the filter cartridges replacement department covered 10 470 households, accounting for 97.19% (10 470/10 773). Conclusions:In Inner Mongolia Autonomous Region, the physical and chemical water improvement areas of drinking water-borne endemic fluorosis are widely distributed, and the normal usage rate of household water purifiers is relatively high. The qualified rate of water fluoride in household water purifiers with filter cartridges used for more than one year is low.
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Objective:To investigate the control situation of drinking water-type endemic fluorosis (hereinafter referred to as drinking water fluorosis) in Xinjiang Production and Construction Corps (hereinafter referred to as the Corps), identify weak links in prevention and control, and provide reference for precise prevention and control of drinking water fluorosis in the Corps.Methods:Monitoring data of drinking water fluorosis areas in the Corps from January to December 2022 were collected from the Corps Center for Disease Control and Prevention, the level of fluoride in drinking water and the prevalence of dental fluorosis in children aged 8 - 12 were analyzed retrospectively.Results:In 2022, the qualified rate of water fluoride in the disease affected TuanChang of the Corps was 100.00% (62/62), and the qualified rate of water fluoride in the disease affected company was 99.44% (705/709). The prevalence of dental fluorosis in children aged 8 - 12 in the disease affected TuanChang was 3.38% (1 412/41 714), and there was no statistically significant difference in the prevalence of dental fluorosis among different age groups (χ 2 = 6.07, P = 0.194). The prevalence of dental fluorosis in children aged 8 - 12 in the TuanChang where the company with water fluoride exceeding standard was located (6.00%, 106/1 768) was higher than that in the TuanChang where the company with qualified water fluoride was located (3.27%, 1 306/39 946, χ 2 = 38.47, P < 0.001). Conclusion:In 2022, the drinking water fluorosis in the Corps has reached the control standard, but attention still should be paid to the water improvement situation and maintenance of water improvement projects in some water fluoride exceeding standard companies, in order to prevent sustained dental fluorosis damage to children in the affected areas, and consolidate the achievements of prevention and control.
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Endemic fluorosis refers to an endemic disease caused by excessive intake of fluoride in the body of residents living in high fluoride environment due to natural or man-made pollution. Dental fluorosis and bone fluorosis are common symptoms of endemic fluorosis. In addition, long-term exposure to fluorine can cause damage to multiple systems such as the central nervous system, cardiovascular system, urinary system, ultimately leading to chronic lesions and functional impairments of multiple organs throughout the body. At present, endemic fluorosis remains one of the serious public health problems in China and even the world. Therefore, this article reviews the research progress on the damage of endemic fluorosis to the human body from both bone and non-bone systems, in order to provide reference for the continuous prevention and control of endemic fluorosis in the future.
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Objective:To analyze the external quality control assessment results of fluoride testing laboratories in endemic disease prevention and control institutions nationwide from 2006 to 2023, investigate the quality control capabilities of these laboratories in various provinces, prefectures, cities, and counties nationwide, and ensure the accuracy and reliability of surveillance data on endemic fluorosis nationwide.Methods:Using retrospective analysis, the external quality control assessment results of all participating fluoride testing laboratories of national endemic disease prevention and control institutions from 2006 to 2023 were summarized and analyzed. The assessment results from 2006 to 2008 were tested for outliers using Grubbs method, homogeneity of variance using Cochran method, excluding the assessment data of unqualified laboratories, calculating the total mean and total standard deviation, Z-score method was used to test the assessment of laboratories, and statistical analysis and judgment were done when the result of │Z│ < 3. The assessment results from 2009 - 2023 were obtained from all laboratories. In 2010, two tests were conducted in the first and second half of the year, and the Z-ratio scores of each laboratory were calculated using robust statistics. When │Z│≤2, the assessment was qualified; when 2 < │Z│ < 3, the assessment was basically qualified; when│Z│≥3, the assessment was unqualified, and the consensus value came from all participating laboratories in the assessment.Results:From the beginning of quality control operation in 2006 to 2023, the number of laboratories participated in external quality control assessments had significantly increased. The number of laboratories participated in water fluoride assessment increased from 30 in 2006 to 1 277 in 2023, and the number of laboratories participated in urine fluoride assessment increased from 29 to 497. The number of laboratories participated in the brick tea fluorine assessment had increased from 43 in 2014 to 193 in 2023. The assessment results showed that when │Z│ < 3, the total qualified rate of fluoride external quality control in fluoride testing laboratories of national endemic disease control institutions was 95.2%, with the lowest being 87.1% (27/31) in 2008 and the highest being 100.0% (394/394) in 2014. When │Z│≤2, the total feedback pass rate was 88.4%, with the lowest being 79.3% (288/363) in the first half of 2010 and the highest being 99.5% (392/394) in 2014. The assessment results showed that when │Z│ < 3, the total pass rate of urine fluoride external quality control in fluoride testing laboratories of national endemic disease control institutions was 98.0%, with the lowest being 86.2% (25/29) in 2006 and 2007, respectively, and the highest being 100.0% (68/68) in 2014. When │Z│≤2, the total qualification rate was 93.7%, with the lowest being 86.5% (64/74) in the second half of 2010 and the highest being 100.0% (68/68) in 2014. The assessment results showed that when│Z│ < 3, the total pass rate of extra-fluoride quality control of brick tea in fluoride testing laboratories of national endemic disease control institutions was 95.4%, with the lowest being 85.0% (164/193) in 2023, and the highest being 100.0% (43/43, 51/51, 79/79) in 2014, 2015 and 2016, respectively. When │Z│≤2, the total pass rate was 89.2%, with the lowest being 72.7% (32/44) in 2017 and the highest being 100.0% (43/43) in 2014. From 2009 to 2023, there were a total of 21 provincial-level laboratories that passed the water fluoride detection assessment, including 3 provinces where all prefecture level and county-level laboratories were qualified. The assessment results of urinary fluorine showed that there were 11 qualified provincial-level laboratories and 1 prefecture-level laboratory. From 2014 to 2023, the assessment results of brick-tea fluorine showed that there were 5 provincial-level laboratories that passed the tea fluorine testing assessment and no prefecture-level laboratory.Conclusions:Conclusion: From 2006 to 2023, the number of fluoride testing laboratories participating in external quality control assessment has increased year by year, and most provincial, municipal and county-level laboratories have good fluoride testing capabilities, which can meet the testing needs of endemic disease prevention and monitoring. For some laboratories with problems, targeted rectification should be carried out to improve the quality of detection, in order to provide better technical support for the monitoring of endemic fluorosis areas.
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La fluorosis dental se caracteriza por una hipomineralización de la estructura dental causada por ingesta excesiva de flúor sistémico. En la dentición decidua, su diagnóstico precoz es importante, dado que será un predictor para la aparición de lesiones en la dentición permanente. El objetivo de esta revisión fue describir la evidencia científica sobre la fluorosis dental en dentición decidua reportando su etiología y factores relacionados, prevalencia, diagnóstico y tratamiento. Se realizaron búsquedas electrónicas en las bases de datos Pub-Med/Medline, EbscoHost y ScienceDirect (noviembre/2020), utilizando las palabras clave "dental fluorosis", "deciduous teeth", "primary tooth", "primary teeth". El desarrollo de fluorosis dental en dentición decidua se relacionó con la ingesta de múltiples fuentes de flúor principalmente, agua potable, alimentos de la dieta, fórmulas infantiles, suplementos y uso de dentífricos fluorados en dosis inadecuadas. Algunos factores prenatales, como vivir en terrenos montañosos o de gran altitud y habitar en lugares cercanos a minas de combustión de carbón, también fueron asociados. La prevalencia de fluorosis dental reportada en los estudios varió entre 6,2 y 96,6 %, dependiendo principalmente de la concentración de flúor en agua potable. Para el diagnóstico de la fluorosis dental en la dentición decidua se deben considerar características como la localización, aspecto, extensión y color de la lesión, realizando diagnóstico diferencial con otro tipo de defectos en esmalte y dentina. Así mismo, el tratamiento de las lesiones dependerá de la severidad del defecto y condiciones individuales del paciente.
Dental fluorosis is characterized by a hypomineralization of the tooth structure caused by excessive intake of systemic fluoride. In the deciduous dentition, its early diagnosis is important since it will be a predictor for the appearance of lesions in the permanent dentition. The objective of this review was to describe the scientific evidence on dental fluorosis in deciduous dentition, reporting its etiology and related factors, prevalence, diagnosis and treatment. Electronic searches were conducted PubMed / Medline, EbscoHost and ScienceDirect (November / 2020) databases, using the keywords "dental fluorosis", "deciduous teeth", "primary tooth", "primary teeth". The development of Dental fluorosis in deciduous dentition was related to the intake of multiple sources of fluoride mainly; drinking water, diet foods, infant formulas, supplements and the use of luoridated toothpastes in inadequate doses. Some prenatal factors such as living in mountainous or high altitude terrain and living in places near coal-burning mines were also associated. The prevalence of dental fluorosis in early childhood reported in the studies varied between 6.2% and 96.6%, depending mainly on the concentration of fluoride in drinking water. For the diagnosis of dental fluorosis in the deciduous dentition, characteristics such as the location, appearance, extension and color of the lesion must be considered, making a differential diagnosis with other types of enamel and dentin defects. Evenly, the treatment of lesions will depend on the severity defects and individual patient conditions.
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Chemicals possessing reactive electrophiles can denature innate proteins leading to undesired toxicity, and the overdose-induced liver injury by drugs containing electrophiles has been one of the major causes of non-approval and withdraw by the US Food and Drug Administration (FDA). Elucidating the associated proteins could guide the future development of therapeutics to circumvent these drugs' toxicities, but was largely limited by the current probing tools due to the steric hindrance of chemical tags including the common "click chemistry" labels. Taking the widely used non-steroidal anti-inflammatory drug acetaminophen (APAP) as an example, we hereby designed and synthesized an APAP analogue using fluorine as a steric-free label. Cell toxicity studies indicated our analogue has similar activity to the parent drug. This analogue was applied to the mouse hepatocellular proteome together with the corresponding desthiobiotin-SH probe for subsequent fluorine-thiol displacement reactions (FTDRs). This set of probes has enabled the labeling and pull-down of hepatocellular target proteins of the APAP metabolite as validated by Western blotting. Our preliminary validation results supported the interaction of APAP with the thioredoxin protein, which is an important redox protein for normal liver function. These results demonstrated that our probes confer minimal steric perturbation and mimic the compounds of interest, allowing for global profiling of interacting proteins. The fluorine-thiol displacement probing system could emerge as a powerful tool to enable the investigation of drug-protein interactions in complex biological environments.
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Objective:To learn about the detection quality and external quality control assessment of fluoride and arsenic in laboratories at all levels in Qinghai Province.Methods:The Z-score method was used to analyze and evaluate the evaluation results of 1 provincial, 8 municipal and 43 county level laboratories of disease prevention and control institutions participating in the external quality control assessment of water fluoride and brick tea fluoride in Qinghai Province in 2021, as well as 1 provincial, 1 municipal and 2 county level laboratories of disease prevention and control institutions participating in the external quality control assessment of water arsenic and urine arsenic. The feedback rate and qualification rate of external quality control of each assessment laboratory were calculated.Results:In 2021, the feedback rate of external quality control of water fluoride, brick tea fluoride, water arsenic and urine arsenic in provincial and municipal level laboratories of Qinghai Province were 100.00%; except that the qualified rate of water fluoride was 7/9, the qualified rate of external quality control of other projects was 100.00%. The feedback rate of external quality control of water fluoride, brick tea fluoride, water arsenic and urine arsenic in county level laboratories was 100.00%; except that the qualified rate of water fluoride was 86.05% (37/43), the qualified rate of external quality control of other projects was 100.00%. In the specific assessment results of the laboratory, the assessment results of water fluoride sample FS20210101 from 1 provincial, 1 municipal and 2 county level laboratories, and FS20210102 from 1 county level laboratory were suspicious; the assessment results of water fluoride sample FS20210101 from 3 county level laboratories were not satisfactory; the assessment results of fluoride and arsenic sample in other laboratories were satisfactory.Conclusions:The qualified rate of external quality control of fluoride and arsenic in laboratories at all levels in Qinghai Province is relatively high, but some county level laboratories are still dissatisfied with the assessment results of water fluoride. Therefore, it is necessary to strengthen the detection level of water fluoride in laboratories.
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Objective:To learn about the levels of 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) in bone tissue of rats with different types of skeletal fluorosis and analyze their correlation.Methods:Thirty 4-week-old SPF grade healthy SD rats were selected. After adaptive feeding for 1 week, the rats were divided into control group (4 ml·kg -1·bw deionized water + standard maintenance diet), osteosclerosis group [20 mg·kg -1·bw sodium fluoride (NaF) + standard maintenance diet], and osteoporosis/osteomalacia group (20 mg·kg -1·bw NaF + low-calcium and low-protein partial diet) according to their body weight (100 - 120 g) by random number table method, with 10 rats in each group, half male and half female; gavaged 6 days each week and the experimental period was 5 months. At the end of the experiment, samples of rat heart blood and lower limb femur were collected. The contents of serum methyl donor S-adenosylmethionine (SAM) and its metabolite S-adenosylhomocysteine (SAH) in serum, and the levels of 5-mC and 5-hmC in bone tissue were measured by enzyme-linked immunosorbent assay (ELISA). Western blot was used to determine the expression of DNA methyltransferase (DNMTs) and DNA hydroxymethylase (TETs) in bone tissue of rats. The correlation between serum SAM content, SAM/SAH ratio and bone tissue 5-mC level, and between the bone tissue 5-mC level and 5-hmC level was analyzed. Results:Serum SAM [11.03 (7.06, 18.63), 3.96 (2.32, 9.09), 3.91 (2.35, 4.46) nmol/L], SAH content [(4.69 ± 0.55), (5.41 ± 1.13), (13.90 ± 1.09) ng/L], SAM/SAH ratio [2.58 (1.54, 4.12), 0.62 (0.52, 1.69), 0.14 (0.13, 0.15)] and bone tissue 5-mC [103.39 (97.37, 109.35), 52.50 (50.19, 68.13), 55.03 (49.97, 59.57) ng/L], 5-hmC levels [(32.61 ± 8.84), (56.96 ± 8.48), (20.34 ± 6.22) ng/L] in the control group, osteosclerosis group and osteoporosis/osteomalacia group were compared, and the differences were statistically significant beween three groups ( H/ F = 12.81, 284.24, 21.85, 19.37, 55.23, P < 0.01). Compared with the control group, the content of SAM, the ratio of SAM/SAH, the level of 5-mC in the osteosclerosis group and osteoporosis/osteomalacia group, and the level of 5-hmC in the osteoporosis/osteomalacia group were lower ( P < 0.05), while the content of SAH in the osteoporosis/osteomalacia group and the level of 5-hmC in the osteosclerosis group were higher ( P < 0.05). Compared with the osteosclerosis group, the content of SAH in the osteoporosis/osteomalacia group was higher, while the ratio of SAM/SAH and the level of 5-hmC were lower ( P < 0.05). Western blot showed that there were statistically significant differences in the expression levels of DNMT1, DNMT3A, DNMT3B, TET1 and TET2 protein in bone tissue of rats in the control group, osteosclerosis group, and osteoporosis/osteomalacia group ( F = 285.45, 345.58, 239.83, 311.52, 318.24, P < 0.001). Among them, the expression levels of DNMT1, DNMT3A and DNMT3B protein in the osteosclerosis group and osteoporosis/osteomalacia group were lower than those in the control group, and the expression levels of DNMT1, DNMT3A and DNMT3B protein in the osteosclerosis/osteomalacia group were lower than those in the osteosclerosis group ( P < 0.05); the expression levels of TET1 and TET2 protein in osteosclerosis group were higher than those in the control group and osteoporosis/osteomalacia group, and the expression levels of TET1 and TET2 protein in the osteoporosis/osteomalacia group were lower than those in the control group ( P < 0.05). The results of Spearman rank correlation analysis showed that the content of SAM and the ratio of SAM/SAH in the control group, osteosclerosis group and osteoporosis/osteomalacia group were positively correlated with the level of 5-mC in bone tissue ( rs = 0.89, 0.92, 0.81, 0.73, 0.87, 0.73, P < 0.05). The levels of 5-mC and 5-hmC in bone tissue of rats in each group were negatively correlated ( rs = - 0.69, - 0.68, - 0.72, P < 0.05). Conclusions:The level of 5-mC in bone tissue of osteosclerotic fluorosis rats is low, and the level of 5-hmC is high, while those of osteoporosis/osteomalacia fluorosis rats are lower. The difference of 5-mC level in bone tissue of rats with different types of skeletal fluorosis is not significant, which may be related to the difference of 5-hmC level in bone tissue.
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Objective:To investigate the effects of fluoride exposure on autophagy and the expression levels of adenosine monophosphate activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and Unc-51-like kinase 1 (ULK1) in mouse neuroblastoma and rat glioma fusion cells (NG108-15 cells).Methods:NG108-15 cells were cultured in vitro and divided into control group (0 mg/L), low fluoride group (20 mg/L), medium fluoride group (40 mg/L) and high fluoride group (80 mg/L) according to the final concentration of sodium fluoride, and the cells were collected after 24 h of treatment for standby. NG108-15 cells autophagy was detected by immunofluorescence/immunocytochemistry (IF/ICC method, the autophagy positive control group was treated with chloroquine phosphate); the mRNA expression levels of AMPK, mTOR and ULK1 in each group were detected by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR); the protein expression levels of autophagy related protein microtubule-associated protein 1 light chain 3B (LC3B), AMPK, mTOR, ULK1, phosphorylation (p)-AMPK, p-mTOR, p-ULK1 in each group were detected by Western blotting. Results:No autophagosome was detected in the control group, and autophagosomes were detected in all the fluoride groups. The protein expression level of LC3B in the low, medium and high fluoride groups (1.80 ± 0.59, 2.16 ± 0.60, 2.30 ± 0.57) was significantly higher than that in the control group (1.00 ± 0.29, P < 0.05). The results of qRT-PCR showed that compared with the control group, the mRNA expression levels of AMPK in medium and high fluoride groups were higher (2.30 ± 0.57, 4.41 ± 1.05 vs 1.00 ± 0.01, P < 0.05); the mRNA expression levels of mTOR in the low, medium and high fluoride groups were lower (0.79 ± 0.04, 0.76 ± 0.09, 0.64 ± 0.10 vs 1.00 ± 0.01, P < 0.05), and the mRNA expression levels of ULK1 were higher (1.81 ± 0.39, 1.96 ± 0.35, 4.22 ± 1.03 vs 1.00 ± 0.01, P < 0.05). The results of Western blotting showed that compared with the control group, the protein expression levels of AMPK (1.21 ± 0.05, 1.20 ± 0.04, 1.30 ± 0.07 vs 1.00 ± 0.03), p-AMPK (1.12 ± 0.05, 1.20 ± 0.06, 1.49 ± 0.07 vs 1.00 ± 0.02), ULK1 (1.16 ± 0.05, 1.26 ± 0.05, 1.15 ± 0.05 vs 1.00 ± 0.04) and p-ULK1 (1.19 ± 0.04, 1.17 ± 0.02, 1.24 ± 0.05 vs 1.00 ± 0.05) in the low, medium and high fluoride groups were higher ( P < 0.05), and the protein expression levels of mTOR were lower (0.77 ± 0.03, 0.60 ± 0.03, 0.55 ± 0.04 vs 1.00 ± 0.04, P < 0.05); the protein expression levels of p-mTOR in the medium and high fluoride groups were lower (0.93 ± 0.05, 0.48 ± 0.02 vs 1.00 ± 0.02, P < 0.05). Conclusion:Fluoride exposure can induce autophagy in NG108-15 cells, and the expression of AMPK and ULK1 are up-regulated, while the expression of mTOR is down-regulated.
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Objective:To observe the changes of serum C-terminal peptide of type Ⅰ collagen (CTX-1) and N-terminal lengthening peptide of type Ⅰ collagen (P1NP) in adult patients with skeletal fluorosis in the tea-drinking-borne endemic fluorosis area in Qinghai Province, and to find sensitive indicators for diagnosis of skeletal fluorosis.Methods:From April to August 2019, a case-control study was carried out in tea-drinking-borne endemic fluorosis area in Zhiduo County, Yushu Tibetan Autonomous Prefecture, and Gangcha County, Haibei Tibetan Autonomous Prefecture of Qinghai Province. According to the Diagnostic Standard for Endemic Skeletal Fluorosis (WS/T 192-2008), the clinical diagnosis and X-ray examination of skeletal fluorosis were carried out for permanent residents ≥25 years old and living for more than 10 years in the area, combined with face-to-face inquiry and investigation of past disease history, lifestyle and clinical manifestations. The patients with skeletal fluorosis and healthy people were selected as skeletal fluorosis group and control group, respectively. Randomized urine samples and fasting venous blood from the two groups were collected. The content of fluoride in urine was determined by ion selective electrode method, and the contents of CTX-1 and P1NP in serum were determined by enzyme-linked immunosorbent assay (ELISA).Results:A total of 127 people in the disease area were investigated, including 63 cases in skeletal fluorosis group and 64 cases in control group. There was no statistically significant difference in age and sex ratio between the two groups ( t = 0.42, χ 2 = 0.07, P > 0.05). The X-ray examination results showed that the patients with skeletal fluorosis were mainly mild, accounting for 71.43% (45/63); X-ray changes were mainly ossification of interosseous membrane and tendon. The urinary fluoride in control group and skeletal fluorosis group was 1.62 (1.12, 1.95) and 3.22 (2.38, 4.89) mg/L, respectively, with statistically significant difference between the two groups ( Z = 7.07, P < 0.001). The difference of serum CTX-1 and P1NP contents between the two groups was statistically significant ( Z = 2.00, 4.89, P < 0.05). Conclusions:The levels of serum CTX-1 and P1NP in patients with skeletal fluorosis are higher than those in healthy people. Serum CTX-1 and P1NP may be used as sensitive indicators for diagnosis of skeletal fluorosis.
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Fluoride has dual health effects. Proper amount of fluoride plays an important role in bone development, prevention of dental caries and nervous system activity. Excessive fluoride causes chronic systemic diseases with dental fluorosis and skeletal fluorosis as the main symptoms. Fluorosis causes morphological and structural changes and function damage in skeletal muscle. Low concentration of fluoride induces muscle canal hypertrophy in skeletal muscle, while high concentration of fluoride leads to skeletal muscle atrophy by causing a series of signal pathway abnormalities. Abnormal changes in phosphatidylinositol-3-hydroxykinase/protein kinase B (PI3K/Akt) signal pathway, oxidative stress, and ubiquitin-proteasome pathway all play important roles in skeletal muscle injury caused by fluorosis. In this paper, the effect of fluoride on skeletal muscle and its related molecular mechanisms are reviewed.
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Objective:To analyze the types and distribution characteristics of elements in drinking water from endemic fluorosis areas with water improvement in Xi'an City, understand the relationship between fluoride and various elements, and conduct health risk assessment on potential high-risk elements.Methods:From May to June 2017, one endemic fluorosis area with water improvement (Gaoling District, Huyi District, Lintong District) was selected according to the northeast, the southwest and the due east directions of Xi'an City as the survey area. Sixteen endemic fluorosis villages were selected from each endemic area, and 2 water samples were collected from each endemic village to detect fluoride and 12 elements such as chromium, manganese, ferrum, copper, zinc, arsenic, selenium, molybdenum, cadmium, antimony, barium, and lead. Hygienic evaluation was conducted according to national standards, and the potential high-risk elements (arsenic, molybdenum) were assessed for health risk through the health risk assessment model recommended by the National Environmental Protection Agency of the United States.Results:The water samples from the endemic fluorosis areas in Xi'an City mainly contained seven elements: barium, ferrum, molybdenum, arsenic, zinc, manganese, and chromium. The content of copper and selenium was relatively low, while the content of cadmium, antimony, and lead was extremely low. The fluoride content in water samples from Gaoling District and Lintong District was relatively high, and the fluorine, arsenic, molybdenum elements was pairwise positively correlated ( P < 0.05). The molybdenum element in water samples from Lintong District exceeded 9.38% (3/32). The fluoride in the water samples of Huyi District was relatively low, and the arsenic, molybdenum elements was positively correlated ( r = 0.84, P < 0.001), and the arsenic element exceeded the standard by 25.00% (8/32). The main health risk of drinking water in endemic fluorosis areas with water improvement in Xi'an City was arsenic exposure, with children at a higher risk than adults, and the areas of Huyi District, Lintong District, and Gaoling District declined, the risk of cancer (CR) of Gaoling District was < 10 -4 and hazard quotient (HQ) was < 1. However, in the areas of Huyi District and Lintong District (except HQ of adults), there was a higher risk (CR > 10 -4, HQ > 1). Children in one endemic fluorosis village in Lintong District had a higher non carcinogenic risk of molybdenum (HQ > 1). Conclusions:The drinking water in endemic fluorosis areas with water improvement in Xi'an City mainly contains 7 elements, especially arsenic and molybdenum, which need to be regularly monitored. Some areas have high health risks of arsenic in water, and monitoring, management, and related epidemiological investigations need to be strengthened. At the same time, it is necessary to actively monitor other toxic and harmful substances that may be introduced during the water improvement process to prevent the occurrence of secondary health problems.
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Objective:To investigate the effects of different labeling conditions on the yield of Al 18F-labeled 1, 4, 7-triazacylononane-1, 4, 7-triaceticacid (NOTA)-prostate specific membrane antigen (PSMA)-137, and to determine the experimental condition for obtaining Al 18F-PSMA-137 probe in high yield. Methods:The effects of different pH values, buffer systems (acetic acid-sodium acetate buffer system and potassium hydrogen phthalate (KHP) buffer system), AlCl 3-ligand ratios, ligand amounts, ethanol volumes and reaction temperatures on the labeling rate were investigated in detail. Results:The pH value of the reaction solution had a significant effect on the labeling rate, and the optimal range was 4.0-4.5. When the pH value was higher than 4.5, the labeling rate decreased significantly. Both the acetic acid-sodium acetate buffer system and the KHP buffer system could be used to label NOTA-PSMA-137 with Al 18F, and the KHP buffer system obtained higher labeling rate. The ratio of AlCl 3-ligand affected the labeling rate, and the highest labeling rate could be obtained when the ratio of AlCl 3-ligand was 0.54-0.62. When the ratio of AlCl 3-ligand was fixed, increasing the amount of ligand could improve the labeling yield. Adding hydrophilic organic solvent ethanol to the reaction system could significantly increase yield, with the highest labeling rate being achieved at a volume of 100 μl ethanol. The most suitable reaction temperature was 100 ℃, and when the temperature raised to 110 ℃, the labeling rate decreased significantly. The most suitable labeling conditions for NOTA-PSMA-137 were as following: 25 μl KHP buffer (0.50 mol/L, pH=4.0), 7.0 μl AlCl 3 solution (20 mmol/L), 200 μl Na 18F solution (74-80 MBq) and 230 μg ligand NOTA-PSMA-137 were mixed in a vial, then stood for 5 min and 100 μl ethanol was added, and all reagents were heated at 100 ℃ for 10 min. The yield of Al 18F-PSMA-137 under above conditions were 85.7%-88.5%. Conclusion:Optimization of labeling condition can improve the yield of Al 18F-PSMA-137 and the stability of the labeling.
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Objective:To prepare a novel targeted prostate specific membrane antigen (PSMA) molecular probe Al 18F-PSMA-136, and evaluate the effects of the change in linker on the biological behavior and tumor targeting ability. Methods:Al 18F-PSMA-136 was prepared by replacing the phenyl of Al 18F-PSMA-137 with cyclohexyl in 1, 4, 7-triazacylononane-1, 4, 7-triaceticacid (NOTA). The inhibition abilities of PSMA of NOTA-PSMA-136 and NOTA-PSMA-137 were determined by N-acetylated-α-linked acidic dipeptidase (NAALADase) method. The radiochemical purity and in vitro stability of the labeled products were analyzed by radio-high-performance liquid chromatography. The PSMA specificity and tumor targeting capability of the probes were investigated in 22Rv1 (PSMA positive-expressing) cells and mouse models. Independent-sample t test was used to analyze the data. Results:The Ki values of NOTA-PSMA-136 and NOTA-PSMA-137 were 3.41 and 0.30 nmol/L, respectively. The labeling yield of Al 18F-PSMA-136 was (30.1±8.4)% and the specific activity was (18.7±5.3) GBq/μmol. The radiochemical purities of the two probes were both greater than 95% and the stabilities in vitro were both good. Both probes showed PSMA-specific in 22Rv1 cells, but the uptake of Al 18F-PSMA-137 was significantly higher than that of Al 18F-PSMA-136 (1 h: (1.67±0.24) vs (1.00±0.01) percentage injected activity per 1×10 5 cells (%IA/1×10 5 cells): t=4.78, P=0.003; 2 h: (2.11±0.06) vs (1.03±0.06) %IA/1×10 5 cells; t=19.90, P<0.001). MicroPET/CT imaging showed that Al 18F-PSMA-136 and Al 18F-PSMA-137 had similar distribution in vivo, mainly concentrated in kidneys, intestine, gallbladder, bladder and tumor. However, the uptake of Al 18F-PSMA-137 in tumor was significantly higher than that of Al 18F-PSMA-136 (1 h: 1.78±0.10 vs 0.54±0.08; t=13.29, P<0.001; 2 h: 1.95±0.01 vs 0.52±0.11; t=18.53, P<0.001). Conclusion:Changes in the NOTA-conjugated linker can significantly affect the PSMA inhibition ability and tumor targeting, and the imaging effect of Al 18F-PSMA-137 with strong lipophilicity is superior.
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The application of isotope exchange can realize radiolabeling in partially aqueous media, proceed under mild reaction conditions, and exclude complex purification procedure. It is suitable for one-step labeling of sensitive biomolecules with clinical application potential. This review systematically introduces the 18F/ 19F isotope exchange reactions based on carbon and those non-carbon-based reaction centers including silicon, boron, phosphorus, sulfur, gallium and iron. Discussions of the effects on isotope exchange radiochemical yields and molar activities by different reaction types, and labeling conditions and substitute groups on classic labeled substrate are held where possible, as well as recent applications in using these methodologies to develop PET probes.