Delayed cerebellar disease and death after accidental exposure to dimethylmercury.
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Cerebellar Diseases↗
Biomedical subjects
T Clarkson
Publications and source records attributed to T Clarkson.
Methylmercury and fish consumption: weighing the risks.
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Animals↗
Health effects of metals: a role for evolution?
Metals have been mined and used since ancient times. The industrial era has seen a sharp increase in both the amounts and variety of metals that find applications in industry. The inadvertent release of metals, such as from fossil fuel consumption, also adds to the global burden. A number of catastrophic outbreaks have alerted us to the occupational and environmental health risks. Life on this planet has evolved in the presence of metals. Cells learned to make use of the more abundant metals in the Archean oceans as an integral component in their structure and function. Today, we inherit these as the essential metals. At the same time, evolving life must have developed means of coping with the potentially toxic actions of metals. The appearance of oxygen in the atmosphere in the Precambrian period also resulted in cells both using and developing protective mechanisms against what must have been a highly toxic, reactive gas. Atmospheric oxygen must have increased the solubility of many metals as insoluble metal sulfides were oxidized to the more soluble sulfates. It may be no coincidence that the protective mechanisms for oxygen are also used to protect against a number of toxic metals. Selected examples are given on the role of evolution in metal toxicology, specifically, examples where the normal function of essential metals is deranged by competition with nonessential metals. Examples are also given of protective mechanisms that involve enzymes or cofactors involved in the oxygen defense system.
Biological Evolution↗
Analysis of data on delayed development from the 1971-72 outbreak of methylmercury poisoning in Iraq: assessment of influential points.
In this paper we report additional results from the analysis of dose-response data on delayed development from the outbreak of methylmercury poisoning in rural Iraq during the winter of 1971-72. The discussion is focused on the importance of four influential points for the estimation of the population threshold for the effects of methylmercury. The point is made that while this study was important for establishing a dose-response relationship in humans, the uncertainty in the parameters of this relationship is large, and further human studies are needed.
Child Development↗
Space exploration and toxicology: a new frontier.
Results of the microbial and immunological studies discussed above clearly illustrate an in-flight or post-flight blunting of the cellular immune mechanism in humans and test animals, coincident with a relative increase in pathogenic microorganisms. This situation predicts an increased incidence of in-flight infectious disease events. To prevent this from occurring, most observers agree that a robust program of preflight and in-flight immunological and microbiological monitoring, combined with an effective countermeasures program, are required for optimally successful long-duration spaceflight.
Animals↗
Methylmercury.
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Dose-Response Relationship, Drug↗
The clinical features of children with malrotation of the intestine.
A review was performed of the 37 cases of malrotation of the intestine which occurred in previously healthy children during a 12-year period. There were 33 patients (89%) younger than eight weeks of age, with 17 patients (46%) aged less than one week. Symptoms included bilious vomiting in 36 patients (97%) and constipation in 33 patients (89%). On initial examination, 35 patients (95%) appeared to be well (including 23/25 patients [92%] with volvulus of the midgut), and 28 patients (76%) exhibited no abnormal physical findings on abdominal examination (including 15/25 patients [60%] with volvulus of the midgut). In all, 25 cases (68%) of malrotation were accompanied by volvulus of the midgut; in 21 of these cases, torsion of the bowel was greater than or equal to 360 degrees. There were four patients (11%) with gangrenous bowel requiring surgical resection. The mortality rate associated with this disorder was 5%; both patients who died were neonates with volvulus who presented in shock and had extensively gangrenous bowel. Malrotation of the intestine usually presents in the young infant, is almost always associated with bilious vomiting, and is commonly accompanied by few if any abnormal physical findings suggestive of a serious underlying intraabdominal disease process. An emergent radiographic contrast study of the upper gastrointestinal tract should be performed to delineate the anatomy of the proximal bowel in all young infants with bilious vomiting.
Child↗
Impact of maternal seafood diet on fetal exposure to mercury, selenium, and lead.
Umbilical cord blood from 1,023 consecutive births in the Faroe Islands showed a median blood-mercury concentration of 121 nmol/l (24.2 micrograms/l); 250 of those samples (25.1%) had blood-mercury concentrations that exceeded 200 nmol/l (40 micrograms/l). Maternal hair mercury concentrations showed a median of 22.5 nmol/g (4.5 micrograms/g), and 130 samples (12.7%) contained concentrations that exceeded 50 nmol/g (10 micrograms/g). Frequent ingestion of whale meat dinners during pregnancy and, to a much lesser degree, frequent consumption of fish, and increased parity or age were associated with high mercury concentrations in cord blood and hair. Blood-mercury levels were slightly lower if the mother had occasionally ingested alcoholic beverages. Mercury in blood correlated moderately with blood selenium (median, 1.40 mumol/l). Increased selenium concentrations were associated with intake of whale meat, alcohol abstention, delivery after term, and high parity. Lead in cord blood was low (median, 82 nmol/l), particularly if the mothers had frequently had fish for dinner and had abstained from smoking.
Alcohol Drinking↗