adam, Author at IAOMT Library

Sodium fluoride exposure exerts toxic effects on porcine oocyte maturation

Excessive long-term fluoride intake is associated with several health problems, including infertility. However, limited information is available on the toxic effects of fluoride exposure on the female reproductive system, especially oocyte maturation. In this study, we investigated the toxic effect of sodium fluoride (NaF) exposure on porcine oocyte maturation and its possible underlying mechanisms. Our results showed that NaF exposure during porcine oocyte maturation inhibited cumulus cell expansion and impaired polar body extrusion. Cell cycle analysis showed that NaF exposure blocked meiotic resumption, disturbed spindle dynamics, disrupted chromosome separation, and increased aneuploidy in porcine oocytes. Moreover, NaF exposure disturbed mitochondrial function, triggered DNA damage response, and induced early apoptosis in porcine oocytes. NaF exposure also induced oxidative stress, decreased GSH level, and increased cathepsin B activity in and impaired the further development potential of porcine oocytes, as indicated by a decrease in blastocyst formation rate, increase in apoptosis, and inhibition of cell proliferation. Together, these results indicate that NaF exposure impairs the maturation capacity of porcine oocytes by inhibiting cumulus cell expansion, disturbing cytoskeletal dynamics, and blocking nuclear and cytoplasmic maturation, thus decreasing the quality and affecting the subsequent embryonic development potential of porcine oocytes.

By Liang S, Nie ZW, Zhao M, Niu YJ, Shin KT, Cui XS.|2018-08-09T20:45:57+00:00January 1st, 2017|Fluoride|

The association between mercury levels and autism spectrum disorders: A systematic review and meta-analysis.

BACKGROUND & AIMS:
The relationship between mercury and autism spectrum disorders (ASD) has always been a topic of controversy among researchers. This study aimed to assess the relationship between ASD and mercury levels in hair, urine, blood, red blood cells (RBC), and brain through a meta-analysis.

METHODS:
A systematic search was performed in several databases including PubMed, ISI Web of Science, Cochrane register of controlled trials, Google Scholar, Scopus, and MagIran until June 2017. Case-control studies evaluating concentration of total mercury in different tissues of ASD patients and comparing them to the healthy subjects (control group) were identified. Necessary data were extracted and random effects model was used to calculate overall effect and its 95% corresponding confidence interval (CI) from the effect sizes.

RESULTS:
A total of 44 studies were identified that met the necessary criteria for meta-analysis. The mercury level in whole blood (Hedges=0.43, 95% CI: 0.12, 0.74, P=0.007), RBC (Hedges=1.61, 95% CI: 0.83, 2.38, P<0.001), and brain (0.61ng/g, 95% CI, 0.02, 1.19, P=0.043) was significantly higher in ASD patients than healthy subjects, whereas mercury level in hair (-0.14mg/g, 95% CI: -0.28, -0.01, P=0.039) was significantly lower in ASD patients than healthy subjects. The mercury level in urine was not significantly different between ASD patients and healthy subjects (0.51mg/g creatinine, 95% CI: -0.14, 1.16, P=0.121).

CONCLUSIONS:
Results of the current meta-analysis revealed that mercury is an important causal factor in the etiology of ASD. It seems that the detoxification and excretory mechanisms are impaired in ASD patients which lead to accumulation of mercury in the body. Future additional studies on mercury levels in different tissues of ASD patients should be undertaken.

By Jafari T, Rostampour N, Fallah AA, Hesami A.|2018-08-08T20:36:24+00:00January 1st, 2017|Mercury|

Reduced mastication impairs memory function.

Mastication is an indispensable oral function related to physical, mental, and social health throughout life. The elderly tend to have a masticatory dysfunction due to tooth loss and fragility in the masticatory muscles with aging, potentially resulting in impaired cognitive function. Masticatory stimulation has influence on the development of the central nervous system (CNS) as well as the growth of maxillofacial tissue in children. Although the relationship between mastication and cognitive function is potentially important in the growth period, the cellular and molecular mechanisms have not been sufficiently elucidated. Here, we show that the reduced mastication resulted in impaired spatial memory and learning function owing to the morphological change and decreased activity in the hippocampus. We used an in vivo model for reduced masticatory stimuli, in which juvenile mice were fed with powder diet and found that masticatory stimulation during the growth period positively regulated long-term spatial memory to promote cognitive function. The functional linkage between mastication and brain was validated by the decrease in neurons, neurogenesis, neuronal activity, and brain-derived neurotrophic factor (BDNF) expression in the hippocampus. These findings taken together provide in vivo evidence for a functional linkage between mastication and cognitive function in the growth period, suggesting a need for novel therapeutic strategies in masticatory function-related cognitive dysfunction.

By Fukushima-Nakayama Y, Ono T, Hayashi M, Inoue M, Wake H, Ono T, Nakashima T.|2019-02-10T21:14:51+00:00January 1st, 2017|Other|

Current progress on understanding the impact of mercury on human health.

Mercury pollution and its impacts on human health is of global concern. The authors of this paper were members of the Plenary Panel on Human Health in the 12th International Conference on Mercury as a Global Pollutant held in Korea in June 2015. The Panel was asked by the conference organizers to address two questions: what is the current understanding of the impacts of mercury exposure on human health and what information is needed to evaluate the effectiveness of the Minamata Convention in lowering exposure and preventing adverse effects. The authors conducted a critical review of the literature published since January 2012 and discussed the current state-of-knowledge in the following areas: environmental exposure and/or risk assessment; kinetics and biomonitoring; effects on children development; effects on adult general populations; effects on artisanal and small-scale gold miners (ASGM); effects on dental workers; risk of ethylmercury in thimerosal-containing vaccines; interactions with nutrients; genetic determinants and; risk communication and management. Knowledge gaps in each area were identified and recommendations for future research were made. The Panel concluded that more knowledge synthesis efforts are needed to translate the research results into management tools for health professionals and policy makers.

By Ha E, Basu N, Bose-O’Reilly S, Dórea JG, McSorley E, Sakamoto M, Chan HM.|2018-07-22T19:48:12+00:00January 1st, 2017|Mercury|

Metal allergy as a cause of implant failure in shoulder arthroplasty.

Metal allergy is an uncommon and poorly understood cause of failure of orthopedic implants. To the authors’ knowledge, there have been no reports of the management of shoulder arthroplasty patients with metal allergy. The authors present their experience with the diagnosis and management of patients with metal allergy. Patients with metal allergy undergoing shoulder arthroplasty were identified through retrospective chart review from January 1, 2012, to January 31, 2015. Case characteristics collected included patient risk factors (age, sex, prior cutaneous reactions to metal), metal allergy factors (type of metal allergy, method of diagnosis), and surgery factors (implant type, primary/revision, type of shoulder arthroplasty). Outcomes measured included American Shoulder and Elbow Surgeons score, Penn Shoulder Score, and Single Assessment Numeric Evaluation score. Eleven patients were identified with metal allergy. Five were diagnosed prior to the index arthroplasty, and 6 were diagnosed after shoulder replacement. The diagnosis was made through skin patch testing, memory lymphocyte immunostimulation assay, or clinical history. Patients identified after implantation presented with progressive pain and stiffness, but none had cutaneous manifestations. Patients with metal allergy had better results undergoing primary shoulder arthroplasty than undergoing revision. Metal allergy is rare but may be a clinically significant cause of unsatisfactory shoulder arthroplasty. Given the superior results of primary shoulder arthroplasty compared with revision, screening for metal allergy by clinical history is recommended. [Orthopedics. 2017; 40(5):e844-e848.].

By Ko JW, Nicholson TA, Hoffler CE, Williams Jr G, Getz C.|2018-07-24T20:04:01+00:00January 1st, 2017|Other|

Ingredients in children’s fluoridated toothpaste: a literature review.

Children’s fluoridated toothpastes are supplemented with ingredients intended to increase appeal. A comprehensive list of children’s toothpastes and their ingredients was compiled from nine pharmacies in New York City. A broad literature review was then conducted to describe the purpose of the ingredient and the known contamination risks associated with chronic consumption of each ingredient. The final sample size comprised 26 children’s toothpastes and 45 unique ingredients. The purpose and known contamination risks of the 45 identified ingredients were documented. A proportion of ingredients (28.9% [n = 13]) were found to be both unnecessary to improving the oral health of children and solely used to increase their appeal. Of this list of unnecessary ingredients, 69.2% (n = 9) were shown to have contamination risks associated with chronic consumption, including enamel demineralization. The authors recommend that toothpaste manufacturing practices be limited to include only ingredients that are necessary for improved oral health and care and only using natural flavorings when needed.

By Basch CH, Kernan WD.|2018-07-18T19:45:24+00:00January 1st, 2017|Fluoride|

Mercury transmitted from mother’s with amalgam dental fillings to fetus.

With great interest, we have read the article by Findik et al. entitled “Mercury concentration in maternal serum, cord blood, and placenta in patients withamalgam dental fillings: effects on fetal biometricmeasurements” that is published in the J Matern Fetal Neonatal Med, Early Online: 1–5, DOI: 10.3109/14767058.2016. 1140737. Findik et al. investigated the extent to which mercury is transmitted from the mother to fetus via the umbilical cord in patients with amalgam dental fillings, and its effect on fetal biometric measurements.

By Mortazavi SM, Mortazavi G, Paknahad M.|2018-07-26T20:33:21+00:00January 1st, 2017|Mercury|

Mercury: The Quintessential Anti-Nutrient.

The chronic effects of cumulative, low-dose mercury exposure are underrecognized by both mainstream and alternative health authorities and, consequently, by the public. Mercury can cause or contribute to most chronic illnesses, including neurological disorders, cardiovascular disease, metabolic syndrome, chronic fatigue, fibromyalgia, adrenal and thyroid problems, autoimmunity, digestive disorders, allergies, chemical sensitivities, mental illness, sleep disorders, and chronic infections such as Lyme and Candida. Mercury toxicity should be suspected in individuals experiencing multiple health problems.
Diagnosis of chronic mercury toxicity is often difficult because the body’s natural defenses may mask or delay symptoms. Natural defenses are a function of genetic susceptibility, epigenetic factors, micronutrient status, and allostatic load (cumulative wear and tear on the body). Furthermore, individuals who retain mercury may counterintuitively show low levels in blood, urine, and hair.
The developmental window from conception through early childhood is one of extreme vulnerability to mercury. Mercury is an epigenetic toxicant (affecting future gene expression) as well as a neurotoxicant. Damage may be permanent; therefore, prevention is key.
For most people mercury is the most significant toxicant in the body. By promoting oxidative stress and depleting antioxidant defenses, including the glutathione system, mercury impairs the body’s response to toxicants in general including mercury itself.
Mercury toxicity creates a need for extra nutrition, both to repair damage and to provide ample enzyme cofactors that can push blocked enzymes. Carbohydrate intolerance can be a symptom of mercury toxicity, and fat can be a preferred fuel. Many people with chronic mercury toxicity have found a nutrient-dense diet to be a useful starting point for symptom relief. Individualized supplementation may also be helpful to overcome the extreme nutritional depletion and unnatural toxic state.

By Russell S, Homme K.|2018-07-30T19:17:42+00:00January 1st, 2017|Mercury|

Prenatal mercury exposure, maternal seafood consumption and associations with child language at five years.

RESULTS:
Median maternal blood mercury concentration was 1.03μg/L, dietary mercury exposure was 0.15μg/kgbw/wk, and seafood intake was 217g/wk. Blood mercury concentrations were not associated with any language and communication scales. Increased dietary mercury exposure was significantly associated with improved SLAS scores when mothers had a seafood intake below 400g/wk in the adjusted analysis. Sibling matched analysis showed a small significant adverse association between those above the 90th percentile dietary mercury exposure and the SLAS scores. Maternal seafood intake during pregnancy was positively associated with the language and communication scales.

CONCLUSION:
Low levels of prenatal mercury exposure were positively associated with language and communication skills at five years. However, the matched sibling analyses suggested an adverse association between mercury and child language skills in the highest exposure group. This indicates that prenatal low level mercury exposure still needs our attention.

By Vejrup K, Brandlistuen RE, Brantsæter AL, Knutsen HK, Caspersen IH, Alexander J, Lundh T, Meltzer HM, Magnus P, Haugen M.|2018-08-13T20:34:08+00:00January 1st, 2017|Mercury|

Prenatal fluoride exposure and cognitive outcomes in children at 4 and 6–12 years of age in Mexico.

BACKGROUND:

Some evidence suggests that fluoride may be neurotoxic to children. Few of the epidemiologic studies have been longitudinal, had individual measures of fluoride exposure, addressed the impact of prenatal exposures or involved more than 100 participants.

OBJECTIVE:

Our aim was to estimate the association of prenatal exposure to fluoride with offspring neurocognitive development.

METHODS:

We studied participants from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) project. An ion-selective electrode technique was used to measure fluoride in archived urine samples taken from mothers during pregnancy and from their children when 6-12 y old, adjusted for urinary creatinine and specific gravity, respectively. Child intelligence was measured by the General Cognitive Index (GCI) of the McCarthy Scales of Children’s Abilities at age 4 and full scale intelligence quotient (IQ) from the Wechsler Abbreviated Scale of Intelligence (WASI) at age 6-12.

RESULTS:

We had complete data on 299 mother-child pairs, of whom 287 and 211 had data for the GCI and IQ analyses, respectively. Mean (SD) values for urinary fluoride in all of the mothers (n=299) and children with available urine samples (n=211) were 0.90 (0.35) mg/L and 0.82 (0.38) mg/L, respectively. In multivariate models we found that an increase in maternal urine fluoride of 0.5mg/L (approximately the IQR) predicted 3.15 (95% CI: -5.42, -0.87) and 2.50 (95% CI -4.12, -0.59) lower offspring GCI and IQ scores, respectively.

CONCLUSIONS:

In this study, higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6-12 y. https://doi.org/10.1289/EHP655.

By Bashash M, Thomas D, Hu H, Angeles Martinez-Mier E, Sanchez BN, Basu N, Peterson KE, Ettinger AS, Wright R, Zhang Z, Liu Y.|2020-01-12T19:18:45+00:00January 1st, 2017|Fluoride|

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About Liang S, Nie ZW, Zhao M, Niu YJ, Shin KT, Cui XS.