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About Komárek A, Lesaffre E, Härkänen T, Declerck D, Virtanen JI.

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So far Komárek A, Lesaffre E, Härkänen T, Declerck D, Virtanen JI. has created 1044 blog entries.

A Bayesian analysis of multivariate doubly-interval-censored dental data.

“A Bayesian survival analysis is presented to examine the effect of fluoride-intake on the time to caries development of the permanent first molars in children between 7 and 12 years of age using a longitudinal study conducted in Flanders. Three problems needed to be addressed. Firstly, since the emergence time of a tooth and the time it experiences caries were recorded yearly, the time to caries is doubly interval censored. Secondly, due to the setup of the study, many emergence times were left-censored. Thirdly, events on teeth of the same child are dependent. Our Bayesian analysis is a modified version of the intensity model of Härkänenet al. (2000, Scandinavian Journal of Statistics 27, 577–588). To tackle the problem of the large number of left-censored observations a similar Finnish data set was introduced. Our analysis shows no convincing effect of fluoride-intake on caries development. “

Neurotoxic effects of postnatal thimerosal are mouse strain dependent.

“The developing brain is uniquely susceptible to the neurotoxic hazard posed by mercurials. Host differences in maturation, metabolism, nutrition, sex, and autoimmunity influence outcomes. How population-based variability affects the safety of the ethylmercury-containing vaccine preservative, thimerosal, is unknown. Reported increases in the prevalence of autism, a highly heritable neuropsychiatric condition, are intensifying public focus on environmental exposures such as thimerosal. Immune profiles and family history in autism are frequently consistent with autoimmunity. We hypothesized that autoimmune propensity influences outcomes in mice following thimerosal challenges that mimic routine childhood immunizations. Autoimmune disease-sensitive SJL/J mice showed growth delay; reduced locomotion; exaggerated response to novelty; and densely packed, hyperchromic hippocampal neurons with altered glutamate receptors and transporters. Strains resistant to autoimmunity, C57BL/6J and BALB/cJ, were not susceptible. These findings implicate genetic influences and provide a model for investigating thimerosal-related neurotoxicity.”

By |2018-05-30T23:12:03+00:00January 1st, 2004|Mercury|

Amalgam studies: disregarding basic principles of mercury toxicity.

“Dental amalgam, which has been used for over 150 years in dental practice, consists of about 50% metallic mercury. Studies on animal and humans show that mercury is continuously released from dental amalgam and absorbed by several body tissues. It is widely accepted that the main source of mercury vapor is dental amalgam and it contributes substantially to mercury load in human body tissues. There is still a controversy about the consequences of this additional mercury exposure from amalgam to human health. Many studies were performed to evaluate possible adverse effects. In this comment, these studies were analyzed with regard to their methodical quality by considering the newest findings on mercury toxicity and metabolism. In sum, a number of studies are methodically flawed drawing inaccurate conclusions as to the safety of dental amalgam.”

By |2018-06-28T20:04:49+00:00January 1st, 2004|Mercury|

Alzheimer disease: mercury as pathogenetic factor and apolipoprotein E as a moderator.

“The etiology of most cases of Alzheimer’s disease (AD) is as yet unknown. Epidemiological studies suggest that environmental factors may be involved beside genetic risk factors. Some studies have shown higher mercury concentrations in brains of deceased and in blood of living patients with Alzheimer’s disease. Experimental studies have found that even smallest amounts of mercury but no other metals in low concentrations were able to cause all nerve cell changes, which are typical for Alzheimer’s disease. The most important genetic risk factor for sporadic Alzheimer’s disease is the presence of the apolipoprotein Ee4 allele whereas the apolipoprotein Ee2 allele reduces the risk of developing Alzheimer’s disease. Some investigators have suggested that apolipoprotein Ee4 has a reduced ability to bind metals like mercury and therefore explain the higher risk for Alzheimer’s disease. Therapeutic approaches embrace pharmaceuticals which bind metals in the brain of patients with Alzheimer’s disease. In sum, both the findings from epidemiological and demographical studies, the frequency of amalgam application in industrialized countries, clinical studies, experimental studies and the dental state of AD patients in comparison to controls suggest a decisive role for inorganic mercury in the etiology of AD.”

Dose-response study of thimerosal-induced murine systemic autoimmunity.

“The organic compound ethylmercurithiosalicylate (thimerosal), which is primarily present in the tissues as ethylmercury, has caused illness and several deaths due to erroneous handling when used as a disinfectant or as a preservative in medical preparations. Lately, possible health effects of thimerosal in childhood vaccines have been much discussed. Thimerosal is a well-known sensitizing agent, although usually of no clinical relevance. In rare cases, thimerosal has caused systemic immune reactions including acrodynia. We have studied if thimerosal might induce the systemic autoimmune condition observed in genetically susceptible mice after exposure to inorganic mercury. A.SW mice were exposed to 1.25-40 mg thimerosal/l drinking water for 70 days. Antinucleolar antibodies, targeting the 34-kDa protein fibrillarin, developed in a dose-related pattern and first appeared after 10 days in the two highest dose groups. The lowest observed adverse effect level (LOAEL) for antifibrillarin antibodies was 2.5 mg thimerosal/l, corresponding to an absorbed dose of 147 microg Hg/kg bw and a concentration of 21 and 1.9 microg Hg/g in the kidney and lymph nodes, respectively. The same LOAEL was found for tissue immune-complex deposits. The total serum concentration of IgE, IgG1, and IgG2a showed a significant dose-related increase in thimerosal-treated mice, with a LOAEL of 5 mg thimerosal/l for IgG1 and IgE, and 20 mg thimerosal/l for IgG2a. The polyclonal B-cell activation showed a significant dose-response relationship with a LOAEL of 10 mg thimerosal/l. Therefore, thimerosal induces in genetically susceptible mice a systemic autoimmune syndrome very similar to that seen after treatment with inorganic mercury, although a higher absorbed dose of Hg is needed using thimerosal. The autoimmune syndrome induced by thimerosal is different from the weaker and more restricted autoimmune reaction observed after treatment with an equipotent dose of methylmercury.”

Occupational risk factors for the development of systemic lupus erythematosus.

“OBJECTIVE:

There have been few studies of occupational exposures and systemic lupus erythematosus (SLE). We examined the association between the risk of SLE and occupational exposures (mercury, solvents, and pesticides), specific jobs (ever worked in teaching, healthcare, and cosmetology), and working night or rotating shifts.

METHODS:

Patients with recently diagnosed SLE (n = 265) were recruited through 4 university based and 30 community based rheumatology practices in North Carolina and South Carolina, USA. Controls (n = 355) were identified through driver’s license records and were frequency matched to patients by age, sex, and state. Data collection included an in-person interview with detailed farming and work histories.

RESULTS:

Associations were seen with self-reported occupational exposure to mercury (OR 3.6, 95% CI 1.3, 10.0), mixing pesticides for agricultural work (OR 7.4, 95% CI 1.4, 40.0), and among dental workers (OR 7.1, 95% CI 2.2, 23.4). Although these associations were fairly strong and statistically significant, the prevalence of these exposures was very low and thus these estimates are based on a small number of exposed cases and controls. Weaker associations were seen between SLE and shift work (OR 1.6, 95% CI 0.99, 2.7) and among healthcare workers with patient contact (OR 1.7, 95% CI 0.99, 2.9). There was no association of SLE with use of solvents or among teachers or cosmetologists.

CONCLUSION:

This study reveals the potential contribution of occupational exposures to the development of SLE, and highlights some exposures and experiences that should be examined in other studies using more extensive exposure assessment techniques and in experimental studies of autoimmunity.”

Contact dermatitis to metals.

“Metals are in close contact with skin and mucous membranes on a repeated, if not constant, basis. Nickel and mercury, well-recognized causes of contact dermatitis; gold and palladium, recently gaining acceptance as patch test allergens on standard screening trays; and cobalt are reviewed in this article. Sensitization to nickel, the most frequently identified allergen on patch testing, is associated with ear piercing. Contact with this potential allergen is ubiquitous. Mercury may be encountered as organic mercury in thimerosal, used as an antiseptic and a preservative in topical medications and vaccines, and metallic mercury found in dental amalgam and thermometers. Both forms may cause contact dermatitis. Gold, recognized as a frequent sensitizer, has been implicated in some cases of eyelid, patchy diffuse and oral lichenoid dermatitis. Cobalt allergy, found frequently in patients who are nickel allergic, also has been associated with ear piercing. Palladium sensitivity is often associated with nickel allergy. However, the incidence of clinical relevance is yet to be established.”

By |2018-04-21T17:26:41+00:00January 1st, 2004|Mercury|

An uncertain risk and an uncertain future: assessing the legal implications of mercury amalgam fillings.

“Trying to buy a mercury thermometer at the local pharmacy these days will result in a deluge of information regarding the risks of mercury and the proper disposal protocol for mercury thermometers as hazardous waste.  Yet, inquiring about the risks of placing mercury in one’s mouth, in the form of a dental filling, is likely to meet with resounding assurances of safety from the dental profession.”

By |2018-04-10T21:20:37+00:00January 1st, 2004|Mercury|

A comparative evaluation of the effects of MMR immunization and mercury doses from thimerosal-containing childhood vaccines on the population prevalence of autism.

“BACKGROUND:
The purpose of the study was to evaluate the effects of MMR immunization and mercury from thimerosal-containing childhood vaccines on the prevalence of autism.

MATERIAL/METHODS:
Evaluations of the Biological Surveillance Summaries of the Centers for Disease Control and Prevention (CDC), the U.S. Department of Education datasets, and the CDC’s yearly live birth estimates were undertaken

RESULTS:
It was determined that there was a close correlation between mercury doses from thimerosal–containing childhood vaccines and the prevalence of autism from the late 1980s through the mid-1990s. In contrast, there was a potential correlation between the number of primary pediatric measles-containing vaccines administered and the prevalence of autism during the 1980s. In addition, it was found that there were statistically significant odds ratios for the development of autism following increasing doses of mercury from thimerosal-containing vaccines (birth cohorts: 1985 and 1990-1995) in comparison to a baseline measurement (birth cohort: 1984). The contribution of thimerosal from childhood vaccines (>50% effect) was greater than MMR vaccine on the prevalence of autism observed in this study.

CONCLUSIONS:
The results of this study agree with a number of previously published studies. These studies have shown that there is biological plausibility and epidemiological evidence showing a direct relationship between increasing doses of mercury from thimerosal-containing vaccines and neurodevelopmental disorders, and measles-containing vaccines and serious neurological disorders. It is recommended that thimerosal be removed from all vaccines, and additional research be undertaken to produce a MMR vaccine with an improved safety profile.”

By |2018-04-23T23:08:20+00:00January 1st, 2004|Mercury|

Neurodevelopmental disorders following thimerosal-containing childhood immunizations: a follow-up analysis.

“The authors previously published the first epidemiological study from the United States associating thimerosal from childhood vaccines with neurodevelopmental disorders (NDs) based upon assessment of the Vaccine Adverse Event Reporting System (VAERS). A number of years have gone by since their previous analysis of the VAERS. The present study was undertaken to determine whether the previously observed effect between thimerosal-containing childhood vaccines and NDs are still apparent in the VAERS as children have had a chance to further mature and potentially be diagnosed with additional NDs. In the present study, a cohort of children receiving thimerosal-containing diphtheria-tetanus-acellular pertussis (DTaP) vaccines in comparison to a cohort of children receiving thimerosal-free DTaP vaccines administered from 1997 through 2000 based upon an assessment of adverse events reported to the VAERS were evaluated. It was determined that there were significantly increased odds ratios (ORs) for autism (OR = 1.8, p < .05), mental retardation (OR = 2.6, p < .002), speech disorder (OR = 2.1, p < .02), personality disorders (OR = 2.6, p < .01), and thinking abnormality (OR = 8.2, p < .01) adverse events reported to the VAERS following thimerosal-containing DTaP vaccines in comparison to thimerosal-free DTaP vaccines. Potential confounders and reporting biases were found to be minimal in this assessment of the VAERS. It was observed, even though the media has reported a potential association between autism and thimerosal exposure, that the other NDs analyzed in this assessment of the VAERS had significantly higher ORs than autism following thimerosal-containing DTaP vaccines in comparison to thimerosal-free DTaP vaccines. The present study provides additional epidemiological evidence supporting previous epidemiological, clinical and experimental evidence that administration of thimerosal-containing vaccines in the United States resulted in a significant number of children developing NDs.”

By |2018-04-21T18:05:58+00:00January 1st, 2004|Mercury|
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