[Life quality in individuals having occupational diseases caused by various occupational factors].

The article presents main results of studies concerning life quality in individuals having chronic occupational diseases of important social value. Life quality in patients with chronic mercurial intoxication and dust bronchitis appeared to result from personal, social and psychologic features.

[Quantitative estimation of the health status dynamics of persons occupationally exposed to mercury vapor: a remote period of intoxication].

The article presents the results of the dynamic clinical observation for persons suffered from occupational chronic mercury intoxication in the remote post-exposure period of the disease. The estimation of the dynamics of syndrome manifestations of chronic mercury intoxication and co-morbidity are presented. The important role of mercury exposure load as a predictor of deterioration of actual health of the patients in the remote period of intoxication is demonstrated.

[Morphologic and neurochemical effects in long-term period of mercurial intoxication (experimental data)].

The article deals with influence of longstanding inhalation of mercurial vapors on behavior of white rats, on morphologic and functional disorders in nervous system, on peculiarities of neuromediators metabolism in brain homogenate over the post-contact period.

Dental amalgam and psychosocial status: the New England Children's Amalgam Trial.

High-dose exposures to elemental mercury vapor cause emotional dysfunction, but it is uncertain whether the levels of exposure that result from having dental amalgam restorations do so. As part of the New England Children's Amalgam Trial, a randomized trial involving 6- to 10-year-old children, we evaluated the hypothesis that restoration of caries using dental amalgam resulted in worse psychosocial outcomes than restoration using mercury-free composite resin. The primary outcome was the parent-completed Child Behavior Checklist. The secondary outcome was children's self-reports using the Behavior Assessment System for Children. Children's psychosocial status was evaluated in relation to three indices of mercury exposure: treatment assignment, surface-years of amalgam, and urinary mercury excretion. All significant associations favored the amalgam group. No evidence was found that exposure to mercury from dental amalgams was associated with adverse psychosocial outcomes over the five-year period following initial placement of amalgams.

[Behavioral activity of white rats under inhalation of metallic mercury].

Prolonged inhalation of metallic mercury vapors by white rats appeared to result in toxic encephalopathy manifesting in disorders of orientative and investigatory, emotional behavior - increased anxiety, aggressiveness, negative e motionalism, higher locomotion activity. Throughout the experiment the animals had increased aggressiveness and muscular tone.

Emotional and motor symptoms in riverside dwellers exposed to mercury in the Amazon. / Manifestações emocionais e motoras de ribeirinhos expostos ao mercúrio na Amazônia.

INTRODUCTION:: The investigation of clinical and neurological impactations associated with exposure to mercury levels in exposed populations is necessary in the Amazon. OBJECTIVE:: To analyze emotional and motor symptoms of riverside dwellers exposed by diet in the municipalities of Itaituba and Acará, in Pará, Brazil. METHODS:: Hair samples were collected to assess the total mercury (HgT). Demographic data as well as emotional (depression, anxiety and insomnia) and motor (paresthesia, muscle weakness, loss of balance when walking, tremors, limb pain and dysarthria) symptomatology data were obtained. RESULTS:: Mean levels of HgT in Itaituba were significantly higher (p < 0.0001) than in Acará. Emotional symptoms were identified in 26 (26.5%) participants from Itaituba and in 24 (52.2%) from Acará. Specific motor complaints in Itaituba occurred in 63 (64.3%) volunteers; the most frequently mentioned afflictions were limb pain (36.7%), paresthesia (32.6%) and muscle weakness (27.5%). In Acará, 33 (71.7%) participants had motor symptoms, the majority of which complained of paresthesia (54.3%), limb pain (52.2%) and tremors (34.8%). Average HgT levels in Itaituba in those with emotional and motor symptoms were above the tolerable levels (6 µg/g) determined by the World Health Organization. CONCLUSION:: Results showed that mercury levels in emotional and motor symptoms in Itaituba are higher than in riverside dwellers in Acará. Further studies, including the application of specific qualitative and/or quantitative standard tests, as well as the investigation of other clinical signs are necessary.

Effects of prenatal exposure to mercury on cognitive and psychomotor function in one-year-old infants: epidemiologic cohort study in Poland.

PURPOSE: The aim of the study is to assess the cognitive and psychomotor status of 1-year-old infants whose mothers were exposed to low, but varying, amounts of mercury during pregnancy. METHODS: Mercury levels in cord and maternal blood at delivery were used to assess prenatal environmental exposure to mercury. Bayley Scales of Infant Development were used to assess neurobehavioral health outcomes. The cohort consisted of 233 infants who were born at 33 to 42 weeks of gestation between January 2001 and March 2003 to mothers attending ambulatory prenatal clinics in the first and second trimesters of pregnancy. Enrollment included only nonsmoking women with singleton pregnancies between the ages of 18 and 35 years who were free from chronic diseases. RESULTS: The geometric mean (GM) for maternal blood mercury level for the group of infants with normal neurocognitive performance was lower (GM = 0.52 mug/L; 95% confidence interval [CI], 0.46-0.58) than that observed in the group with delayed performance (GM = 0.75 mug/L; 95% CI, 0.59-0.94), and this difference was significant (p = 0.010). The GM of cord blood mercury level in the normal group also was lower (GM = 0.85 mug/L; 95% CI, 0.78-0.93) than that observed in the group with delayed performance (GM = 1.05 mug/L; 95% CI, 0.87-1.27), and this difference was of borderline significance (p = 0.070). The relative risk (RR) for delayed performance increased more than threefold (RR = 3.58; 95% CI, 1.40-9.14) if cord blood mercury level was greater than 0.80 mug/L. Risk for delayed performance in the group of infants with greater maternal mercury levels (>0.50 mug/L) also was significantly greater (RR = 2.82; 95% CI, 1.17-6.79) compared with children whose mothers had mercury levels less than 0.50 mug/L. CONCLUSIONS: The results may be of public health importance because delayed psychomotor or mental performance in infants is assumed to be an indicator of later neurocognitive development in children, which may persist into adult life.

Behavioral changes in metallothionein-null mice after the cessation of long-term, low-level exposure to mercury vapor.

The neurobehavioral changes in wild-type and metallothionein (MT)-null mice after the cessation of long-term, low-level exposure to Hg0 were investigated. MT-null and wild-type females were continuously (24 h/day) exposed to mercury vapor (Hg0) at 0.055 mg/m3 (range: 0.043-0.073 mg/m3), which was similar to the current threshold limit value (TLV), for 29 weeks. The effects on behavior, such as locomotor activity in the open field (OPF), learning ability in the passive avoidance response (PA) and spatial learning ability in the Morris water maze (MM) were examined immediately and 12 weeks after the cessation of exposure. Immediately after the exposure had ceased, total locomotor activity in OPF was decreased in the both strain of mice, although the MT-null mice appeared to show more distinct effect. In the PA test, the exposed animals of both strains showed learning impairment as compared to un-exposed mice. Twelve weeks after the cessation of exposure, the locomotor activity in OPF was elevated in the exposed mice of both strains, while the learning ability in the PA test appeared normal in both strains. Spatial learning ability was not affected at all. Immediately after the exposure had ceased, the brain mercury concentration of the exposed wild-type mice was 1.75 microg/g, twofold of that in the MT-null mice. In 12 weeks, brain mercury levels decreased to approximately 1/20 of those in immediately after the exposure in both of the strains. These results for the first time indicated that long-term, low-level exposure to Hg0 could exert neurobehavioral effects, which were not reversible even after a long exposure-free period. Whereas the effects on learning ability were presumably transient, the effects on spontaneous behavior as evaluated in OPF were persistent. Finally, the MT-null mice seemed more susceptible to Hg0-induced neurotoxicity than the wild-type mice, confirming our previous results.

Psychiatric manifestations of mercury poisoning.

Mercury and its compounds are toxic substances that are widely used in industry and agriculture. Mercury poisoning is an uncommon but important clinical entity that often presents with psychiatric disturbances as a prominent part of the clinical picture. In this paper, a case of mercury poisoning in a 12-year-old girl with prominent psychiatric manifestations is presented. Relevant literature concerning the psychiatric manifestations of mercury poisoning is discussed. The importance of considering mercury poisoning, and toxic conditions in general, in the differential diagnosis of psychiatric disorders is emphasized.

Widespread neuronal degeneration in rats following oral administration of methylmercury during the postnatal developing phase: a model of fetal-type minamata disease.

The neurotoxicity of methylmercury (MeHg) treatment during the postnatal developing phase in rats was studied. Rats on postnatal day 1 were orally administered 5 mg/kg/day methylmercury chloride (MMC) for more than 30 consecutive days. Body weight loss began 26 days after MMC was administered, and severe paralysis of the hind-limbs and unsteadiness appeared subsequently. Histopathologically, the widespread neuronal degeneration was observed in the cerebral neocortex, neostriatum, red nucleus, brainstem, cerebellum and spinal dorsal root ganglia on day 32. The widespread distribution of the lesions was quite similar to that in fetal cases of MeHg intoxication in Minamata, Japan. These findings suggest that MMC treatment during the postnatal development phase in rats produce a good model of fetal-type Minamata disease.

Acute mercury intoxication examined with coordination ability and tremor.

At a mercury spill, several workers were exposed to mercury vapour concentrations up to 0.15 mg/m3. Two weeks after, 38 exposed workers were examined. Fourteen had a Hg in urine concentration above 25 nmol/l. Two exposed groups (n = 7) and an unexposed control group (n = 15) were formed, based on Hg in urine: a HI group with mean = 106.5 nmol/l (range: 49.5-249); a LO group with mean = 35.2 nmol/l (range: 28.8-48.0), and control group with mean = 10.5 nmol/l (range: 4.5-14.1). The groups were reexamined 3 and 16 months later. The groups were examined with two computer-based portable test systems. CATSYS quantifies hand pronation/supination, finger tapping, and reaction time. TREMOR records and analyses tremor at the finger tips. The results showed reduced coordination ability in the HI group at the first examination compared to the control group. Tremor intensity was very high in the HI group and decreased only slightly during the follow-up period. The study indicates that quantification of coordination ability and tremor intensity can be used within occupational medicine for the assessment of the impact of acute mercury intoxication.

Serotonin production in lymphocytes and mercury intolerance.

Patients with suspected illness due to mercury in dental amalgam were classified as tolerant or intolerant depending on their psychosomatic responses following in vivo epicutaneous provocation with low doses (patch test doses) of metallic mercury and phenylmercuric acetate. Ten intolerant patients and nine tolerant patients plus seven healthy amalgam-free and metal non-allergic controls were recruited to the study. Peripheral blood lymphocytes were exposed in vitro to three concentration of mercuric chloride (0.92, 1.83 and 3.68 microM) with and without 10 microg phytohaemagglutinine (PHA)/ml and the release of serotonin into the supernatant was measured. Lymphocytes exposed only to HgCl(2) showed no significant dose-dependent increase of serotonin, but the response of the tolerant patients was significantly higher compared with the controls. No other differences were found. Co-culture with mercuric chloride and PHA showed a statistically significant dose-dependant release of serotonin, but no differences between the three clinical groups could be detected. Thus, our results could not validate the concept of mercury tolerance and intolerance.

Psychological performance and long-term exposure to mercury vapors.

In a cross-sectional study the psychological test performances of a group of 36 male chlorine-alkali workers were compared with the level of exposure to mercury and to the corresponding results of referents. The mercury exposure had lasted for at least 10 years and had been controlled by regular health examinations and urine analyses. Several dose indicators were calculated. The more heavily exposed workers performed more poorly on the verbal intelligence test (Similarities) than the referents did. Impairments in the memory tests showed a statistically significant correlation with the actual exposure level, especially with the actual concentration of mercury in blood. The monitoring of mercury in blood can be useful in health surveillance programs. The level of mercury in the air was calculated from the dose indicators. The results support the recommended exposure limit of 25 micrograms/m3 for metallic mercury vapor in the air as a level avoiding adverse effects in exposed workers.

Experiences from the amalgam unit at Huddinge hospital--somatic and psychosomatic aspects.

The "amalgam unit" at the Huddinge University Hospital in Sweden examined 379 of 1300 patients referred for health problems which the patients related to amalgam tooth fillings. Toxicologic, clinical, odontological, and psychiatric examinations were performed. More than 30% had medical causes for their complaints; 7% had severe diseases which had been unrecognized. The most common symptoms were diffuse pain, general weakness, fatigue, headache, and difficulties in concentrating. Anxiety and depression were the most prevalent psychiatric complaints. The psychological examination revealed a high prevalence of somatization. The treatment was information about mercury and amalgam, appropriate odontological routines without removal of intact amalgam fillings, medical therapy when necessary, and strengthening of the patients' social networks. Ninety percent were satisfied with the treatment. The results indicate that there are various explanations for the complaints of patients fearing "amalgam disease". No cases of mercury intoxication were found.

Occupational and environmental toxicology of mercury and its compounds.

Mercury exists in various chemical forms. The important forms from a toxicological viewpoint are the metallic form, also called the elemental form, the divalent inorganic forms and methylmercury compounds. Elemental (Hg0) mercury has a high vapor pressure and the vapor causes a number of cases of poisoning via inhalation. Classical mercury poisoning is characterized by a triad of signs, namely tremors, erethism and gingivitis. Mercurial erethism, which is characterized by behavioral and personality changes such as extreme shyness, excitability, loss of memory, and insomnia are also observed. Recently, the effects of mercury exposure at levels around 0.05 mg/m3 or lower have been of concern and may include minor renal tubular damage, increased complaints of tiredness, memory disturbance and other symptoms, subclinical finger tremor, abnormal EEG by computerized analysis and impaired performance in neurobehavioral or neuropsychological tests. Abnormal gait, dysarthria, ataxia, deafness and constriction of the visual field are typical of the symptoms of methylmercury poisoning observed in Minamata and Iraqi outbreaks, as well as in occupational methylmercury poisoning cases. Furthermore, an infant born to a mother with excessive methylmercury consumption showed various neurological disturbances and delayed development. Since several populations are believed to be still exposed to methylmercury through the consumption of fish and sea mammals, neurobehavioral deviations in children of these populations have recently been investigated.

Chronic insomnia in workers poisoned by inorganic mercury: psychological and adaptive aspects.

Insomnia is one of the symptoms of inorganic mercury poisoning (IMP). The objective of this study is to analyze the chief psychological aspects in the adjustment of workers with chronic insomnia associated with IMP. For this purpose the Preventive Clinical Interview and the Ryad Simon Operational Adaptive Diagnostic Scale (Escala Diagnóstica Adaptativa Operacionalizada-EDAO) were utilized. Fifteen subjects with mean age of 40 years (10 males and 5 females) were studied. Nine were diagnosed with High Adaptive Inefficacy, five with Moderate Inefficient Adaptation and only one with Mild Inefficient Adaptation. Impairment occurred in four adaptive sectors: affective relationship, social-cultural, productivity and organic. Adaptive efficiency indicated that in all the 15 subjects studied the adaptive solutions were frustrating and led to psychic suffering and/or environmental conflict confirming the severity of the involvement in chronic IMP.

[Clinico-neuro-psychological evaluation of workers exposed to metallic mercury in the electric lamp industry]. / Avaliação clinico-neuro-psicológica de trabalhdores expostos a mercúrio metálico em indústria de lâmpadas elétricas.

This research project was undertaken for the purpose of studying poisoning by metallic mercury among workers of an electric lamp factory located in S. Paulo (Brazil). 71 workers were investigated, of whom 61 (85.92%) were chronically poisoned. Exposure period ranged from 4 months to 30 years. The 57 (80.30%) of chronically poisoned workers showed poor psychomotor co-ordination, 56 (78.88%) showed neurological impairments, 51 (71.83%) decreases in memory capacity, 47 (66.20%) pathological findings in the clinical exam, 45 (63.38%) psychiatric disturbances and 37 (52.10%) poor performance in the concentration test.

Psychometric evidence that mercury from silver dental fillings may be an etiological factor in depression, excessive anger, and anxiety.

Scores on the Beck Depression Inventory were compared for 25 women who had silver dental fillings (amalgams) and for 23 women without amalgams. Women with amalgams had significantly higher scores and reported more symptoms of fatigue and insomnia. Anger scores from the State-Trait Anger Expression Inventory showed that the women with amalgams had statistically significantly higher mean scores on expressing anger without provocation and experiencing more intense angry feelings. The women without amalgams scored significantly higher on controlling anger, which suggested they invested more energy in monitoring and preventing the experience and expression of anger. Anxiety scores from the State-Trait Anxiety Inventory showed the women with amalgams scored significantly less pleasant, satisfied, happy, secure, and steady, and had a more difficult time making decisions. They had significantly higher Trait Anxiety scores. The women with amalgams also had significantly higher levels of mercury in the oral cavity before and after chewing gum. The study suggests that amalgam mercury may be an etiological factor in depression, excessive anger, and anxiety because mercury can produce such symptoms perhaps by affecting the neurotransmitters in the brain.

A comparison of mental health of multiple sclerosis patients with silver/mercury dental fillings and those with fillings removed.

In this study was compared the mental health status of 47 multiple sclerosis patients with silver/mercury tooth fillings (amalgams) to that of 50 patients with their fillings removed. On the Beck Depression Inventory the multiple sclerosis subjects with amalgams suffered significantly more depression while their scores on the State-Trait Anger Expression Inventory indicated the former group also exhibited significantly more anger. On the SCL-90 Revised, subjects with amalgam fillings had significantly more symptoms of depression, hostility, psychotism, and were more obsessive-compulsive than the patients with such fillings removed. On a questionnaire containing 18 mental health symptoms multiple sclerosis subjects with amalgam fillings reported a history of 43% more symptoms than those without amalgam fillings over the past 12 months. These data suggested that the poorer mental health status exhibited by multiple sclerosis subjects with dental amalgam fillings may be associated with mercury toxicity from the amalgam.