Assessment of baseline ecotoxicity of sediments from a prospective mining area enriched in light rare earth elements.

Rare earth elements (REEs) disperse from indigenous rocks to the environment, thus making sediments one of the major sinks and sources of metal pollution. The emerging use of REEs and the subsequent opening of new mining areas may contribute to their release into surrounding ecosystems. For this reason, this study was performed in a natural area with geological material abundant in ferrocarbonatites and light REE. The aim of this work was to assess the natural REE availability and (eco)toxicity in freshwater sediments. Sediments showed high REE concentrations in samples with fine grain size fractions, and low in organic-rich sediments. The enrichment in LREE was mostly from rocks and the obtained enrichment factors (EF) confirmed that the sediments are not anthropogenically polluted. To assess REE availability and ecotoxicity, four toxicity tests were performed. REEs measured as the dissolved concentration in the test media were very low compared to the potentially available total REE in sediments and showed positive or negative correlations with fine or coarse grain sizes, respectively, and positive correlations with the content in Mg, Fe and Al. In tests performed in media supplemented with salts, the availability of REEs decreased considerably. Only some toxic effects could be linked to the REE contents in the ostracodtox and luminotox tests. However, measurement of toxicity could be influenced by the sediment properties and lead to a potential overestimation of ecotoxicity if only REE are regarded. Our study reveals that the physicochemical properties of sediments are a key factor controlling both REE availability and toxicity, whereas the determination of REE effects from toxicity tests using liquid media with salt addition will decrease REE availability and could mask toxic effects. Our findings provide new knowledge about REE behaviour in sediments and are a starting point for understanding potential REE pollution around prospective mining areas.

Does nitrate co-pollution affect biological responses of an aquatic plant to two common herbicides?

Aquatic systems in agricultural landscapes are subjected to multiple stressors, among them pesticide and nitrate run-off, but effects of both together have rarely been studied. We investigated possible stress-specific and interaction effects using the new OECD test organism, Myriophyllum spicatum, a widespread aquatic plant. In a fully factorial design, we used two widely applied herbicides, isoproturon and mesosulfuron-methyl, in concentration-response curves at two nitrate levels (219.63 and 878.52mg N-NO3). We applied different endpoints reflecting plant performance such as growth, pigment content, content in phenolic compounds, and plant stoichiometry. Relative growth rates based on length (RGR-L) were affected strongly by both herbicides, while effects on relative growth rate based on dry weight (RGR-DW) were apparent for isoproturon but hardly visible for mesosulfuron-methyl due to an increase in dry matter content. The higher nitrate level further reduced growth rates, specifically with mesosulfuron-methyl. Effects were visible between 50 and 500µgL(-1) for isoproturon and 0.5-5µgL(-1) for mesosulfuron-methyl, with some differences between endpoints. The two herbicides had opposite effects on chlorophyll, carotenoid and nitrogen contents in plants, with values increasing with increasing concentrations of isoproturon and decreasing for mesosulfuron-methyl. Herbicides and nitrate level exhibited distinct effects on the content in phenolic compounds, with higher nitrate levels reducing total phenolic compounds in controls and with isoproturon, but not with mesosulfuron-methyl. Increasing concentrations of mesosulfuron-methyl lead to a decline of total phenolic compounds, while isoproturon had little effect. Contents of carbon, nitrogen and phosphorus changed depending on the stressor combination. We observed higher phosphorus levels in plants exposed to certain concentrations of herbicides, potentially indicating a metabolic response. The C:N molar ratio decreased strongly with isoproturon and increased with mesosulfuron-methyl. The C:P and N:P ratios did not vary for most herbicide concentrations, indicating homeostasis. Nitrate level had no effect on the C:N ratio, but the N:P ratio increased in high nitrate level treatments, indicating that the former is more strictly regulated by the plant than the latter. We conclude that the multi-stress impacts caused to aquatic primary producers by herbicides and nitrate enrichment, as often observed in agricultural run-off, not only affected growth and pigment content, but also structural traits (dry matter content) and other physiological traits (elemental stoichiometry, phenolic compounds). Changes in those might have indirect effects on biotic interactions and elemental cycles. We suggest considering some of these endpoints in future studies in environmental risk assessment for agricultural run-off.

Light-emitting electrochemical processes.

Electrochemical processes leading to light emission are reviewed, with emphasis on aspects of this subject relevant to the understanding and optimization of electrogenerated luminescence (EL) in organic thin-film materials. The basic energetic requirements of light emission from electrochemically initiated solution redox reactions [electrogenerated chemiluminescence (ECL)] are reviewed first. This review is followed by a discussion of light-emitting electrochemical processes that have been observed in hybrids of ionically conducting polymers and electronically conducting polymers. Finally, the features of EL in insulating polymers and molecular thin films are reviewed, along with recent electrochemical and ECL studies of the small-molecule components of certain organic light-emitting diodes. These studies provide a conceptual framework for understanding and optimizing these materials and the EL process.

Irreversible sensorineural hearing loss as a result of azithromycin ototoxicity. A case report.

Azithromycin, an azalide antibiotic, rarely causes ototoxicity. According to the few reports in existence, azithromycin-induced ototoxicity occurred following prolonged high-dose therapy in patients with acquired immunodeficiency syndrome and resulted in a reversible sensorineural hearing loss. We present a case of irreversible sensorineural hearing loss due to azithromycin ototoxicity in an otherwise healthy woman following low-dose exposure to azithromycin.

Intractable benign paroxysmal positional vertigo in patients with Meniere's disease.

OBJECTIVE: To provide a detailed description of the coexistence of benign paroxysmal positional vertigo (BPPV) and Meniere's disease in individuals and to offer a possible mechanism that explains the findings in these patients. STUDY DESIGN: Retrospective. METHODS: Chart review. RESULTS: Of 162 patients diagnosed with Meniere's disease between January 1998 and January 1999, 9 were found to have both "definite" Meniere's disease and "certain" BPPV. Meniere's symptoms preceded the onset of BPPV in all of our patients. Seven of the 9 patients were female. Except for one patient who experienced BPPV bilaterally, BPPV was limited to the same ear as the Meniere's disease. All patients presented with intractable BPPV that did not respond completely to otolith repositioning procedures. A detailed description of five patients is presented. CONCLUSION: Our data, in conjunction with that of others, suggest that Meniere's disease may predispose patients to intractable BPPV. Hydropically induced damage to the maculae of the utricle and saccule or partial obstruction of the membranous labyrinth may be possible mechanisms that explain the coexistence of Meniere's disease and BPPV.

Quality assurance responsibilities as defined by the EPA Good Automated Laboratory Practices (GALPs).

In December 1990, the Environmental Protection Agency's (EPA) Office of Information Resources Management (OIRM) issued a draft of the Good Automated Laboratory Practices (GALP). The GALPs developed from a union of existing Federal and EPA regulations and policies, including: the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) & Toxic Substance Control Act (TSCA), Good Laboratory Practices (GLP), the EPA Information Resources Management Policy (IRMP), and the Computer Security Act of 1987. The GALPs consolidate the regulations and policies to provide a single source of reference, and sever as an extension of the GLP standards (40 CFR 160 & 792). Whereas the GLPs describe acceptable laboratory management practices, the GALPs describe acceptable automated data management practices, and give guidance for standardizing and implementing procedures to ensure the quality and integrity of automated data collection and storage. The GALPs have been formatted to parallel the structure of the GLPs. Just as the GLPs define the responsibilities of the Quality Assurance Unit (QAU) in maintaining good laboratory practices, the GALPs define the responsibilities of the QAU in maintaining good automated data practices. The QAU is charged with (i) maintaining copies of written procedures for the automated data collection system, (ii) performing inspections of laboratory operations utilizing the automated data collection system and reporting findings, (iii) ensuring authorization and documentation of deviations from written procedures, (iv) auditing data and reports from the automated data collection system to ensure they accurately represent the raw data, and (v) maintaining records of the above-defined QAU functions.(ABSTRACT TRUNCATED AT 250 WORDS)

The epidemiology of echinococcosis in Israel.

Shifts in population and employment patterns in Israel since 1948 have been accompanied by profound changes in the distribution of echinococcal disease. Formerly, it was most commonly imported with the mass immigration of Jews after 1948 from the Arab countries of North Africa and Asia Minor, and appeared to be relatively uncommon in Israel-born Jews and Arabs. In 1980 the disease was made notifiable, and this paper presents a review of the years 1981-1989. The prevalence pattern that prevailed after the end of mass immigration has reversed so that cases are now twice as common in Arabs as in Jews. Among the Arabs the disease appears most commonly in the north of the country, especially among the Druze, less commonly among Christians and least in Muslims. We suggest that this prevalence pattern is related largely to home slaughter of sheep, to differing attitudes to dogs, and possibly also to the hunting of wild pig. Targetted education and better enforcement of existing regulations can lead to a reduction in disease.

Milkborne gastroenteritis due to Staphylococcus aureus enterotoxin B from a goat with mastitis.

Three children developed Staphylococcus aureus food poisoning due to enterotoxin type B following ingestion of milk from a goat with overt mastitis.

Increased risk of suicide in persons with AIDS.

The rate of suicide has been reported to be higher in persons with chronic and life-threatening illnesses (eg, cancer, Huntington's disease, and renal failure). We studied the rate of suicide in 1985 in New York City residents diagnosed with the acquired immunodeficiency syndrome (AIDS). There were 668 suicides in New York City residents in 1985, yielding a rate of 9.29 per 100,000 person-years. In men aged 20 to 59 years without a known diagnosis of AIDS, the rate was 18.75 per 100,000 person-years. There were 3828 individuals who lived with the diagnosis of AIDS for some part, or all, of 1985. There were 12 suicides in men aged 20 to 59 years from this group who lived 1763.25 person-years with a diagnosis of AIDS. This yields a suicide rate of 680.56 per 100,000 person-years. Thus, the relative risk of suicide in men with AIDS aged 20 to 59 years was 36.30 times (95% confidence limits, 20.45 to 64.42) that of men aged 20 to 59 years without this diagnosis, and 66.15 times (95% confidence limits, 37.38 to 117.06) that of the general population. We conclude that AIDS represents a significant risk factor for suicide.

Comparison of two dosage schedules of doxycycline in children with rickettsial spotted fever.

We carried out a randomized clinical trial with oral doxycycline in children with Israel rickettsial spotted fever. Our purpose was to investigate whether an abbreviated course of therapy with this drug (until the patient was afebrile plus one day) would be as effective as a one-week regimen of therapy. Results with 50 pediatric patients during this three-year study indicated that the abbreviated treatment regimen was as effective. This clinical trial may serve as a model for determining shorter durations of therapy for other diseases.

Israeli rickettsial spotted fever in children. A review of 54 cases.

We observed and recorded clinical and laboratory data from 54 children with fever and a maculo-papular rash admitted to Soroka Medical Center, Beersheva, Israel suffering from serologically confirmed rickettsial spotted fever. The rash generally began on the palms and soles and extended centripetally to the torso. Other clinical findings included myalgia, headache, hepatomegaly, and splenomegaly. None had a "tache noire". A left shift in the white cells, leucopenia, thrombocytopenia, hyponatraemia and impaired liver function tests were common laboratory abnormalities. All recovered following oral doxycycline therapy. Serious sequelae such as myocarditis, encephalitis, and disseminated intravascular coagulation, as reported in Rocky Mountain spotted fever, did not occur.

A study of homicides in Manhattan, 1981.

There were 573 persons murdered in Manhattan (New York) during 1981 for an overall rate of 40.5 per 100,000 population. The male, young, and Black or Latino populations were at higher risk of being homicide victims. For male victims, the homicides were the result of disputes in 37.6 per cent of the cases, drug-related activities in 37.6 per cent, and robbery and other criminal activities in 24.8 per cent of cases. For female victims, homicides resulted from disputes in 62.2 per cent of cases, drug-related activities in 13.8 per cent, and robberies in 20.0 per cent of cases. The observed proportion of homicides related to drug and other criminal activities was higher than has been reported previously in the United States. The role of alcohol continued to be important in homicides related to disputes. The authors stress the importance of differentiating drug-related homicides from those associated with other criminal activities.

Post-exposure rabies prophylaxis: establishing effectiveness of abbreviated treatments.

Several publications have reported recently the apparently successful use of human diploid cell rabies vaccine (HDCV) in volumes of less than the 6 X 1.0 cm3 dosage schedule currently recommended by the World Health Organization for post-exposure rabies prophylaxis. The newer proposed treatments are advocated to economize on an expensive product that may be available rarely in many Third World areas.