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Alzheimer's disease (AD) is the most common neuronal disorder that leads to the development of dementia. Until nowadays, some therapies may alleviate the symptoms, but there is no pharmacological treatment. Microdosing lithium has been used to modify the pathological characteristics of the disease, with effects in both experimental and clinical conditions. The present work aimed to analyze the effects of this treatment on spatial memory, anxiety, and molecular mechanisms related to long-term memory formation during the aging process of a mouse model of accelerated aging (SAMP-8). Female SAMP-8 showed learning and memory impairments together with disruption of memory mechanisms, neuronal loss, and increased density of senile plaques compared to their natural control strain, the senescence-accelerated mouse resistant (SAMR-1). Chronic treatment with lithium promoted memory maintenance, reduction in anxiety, and maintenance of proteins related to memory formation and neuronal density. The density of senile plaques was also reduced. An increase in the density of gamma-aminobutyric acid A (GABAA) and α7 nicotinic cholinergic receptors was also observed and related to neuroprotection and anxiety reduction. In addition, this microdose of lithium inhibited the activation of glycogen synthase kinase-3beta (GSK-3ß), the classical mechanism of lithium cell effects, which could contribute to the preservation of the memory mechanism and reduction in senile plaque formation. This work shows that lithium effects in neuroprotection along the aging process are not related to a unique cellular mechanism but produce multiple effects that slowly protect the brain along the aging process.

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It was already shown that microdoses of lithium carbonate (Li2CO3) promoted memory stabilization in humans and mice. Prolonged treatment also reduced neuronal loss and increased the density of the neurotrophin BDNF in transgenic mice for Alzheimer's disease. The aim of this study was to evaluate whether lithium ions affect inflammatory profiles and neuronal integrity in an animal model of accelerated senescence (SAMP-8). Organotypic hippocampal cultures obtained from 11 to 12-month-old SAMP-8 mice were treated with 2 µM, 20 µM and 200 µM Li2CO3. 2 µM Li2CO3 promoted a significant reduction in propidium iodide uptake in the CA2 area of hippocampus, whereas 20 µM promoted neuroprotection in the CA3 and GrDG areas. 200 µM caused an increase in cellular death, showing toxicity. Measured with quantitative PCR, IL-1α, IL-6 and MIP-1B/CCL-4 gene expression was significantly reduced with 20 µM Li2CO3, whereas IL-10 gene expression was significantly increased with the same concentration. In addition, 2 µM and 20 µM Li2CO3 were also effective in reducing the activation of NFkB and inflammatory cytokines densities, as evaluated by ELISA. It is concluded that very low doses of Li2CO3 can play an important role in neuroprotection as it can reduce neuronal loss and neuroinflammation in older individuals.

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A simple and green technique named polymer-supported ionic liquid solid phase extraction (PSIL-SPE) was developed for mercury (Hg) species determination. Inorganic Hg (InHg) species was complexed with chloride ions followed by its introduction into a flow injection on-line system to quantitatively retain the anionic chlorocomplex (HgCl4(2-)) in a column packed with CYPHOS(®) IL 101-impregnated resin. The trapped InHg was then reduced with stannous chloride (SnCl2) and eluted with the same flow of reducing agent followed by cold vapor atomic absorption spectrometry (CV-AAS) detection. Organic mercury species (OrgHg) did not interact with the impregnated resin and were not retained into the column. Total concentration of OrgHg was evaluated by difference between total Hg and InHg concentration. A 95% extraction efficiency was achieved for InHg when the procedure was developed under optimal experimental conditions. The limit of detection obtained for preconcentration of 40 mL of sample was 2.4 ng L(-1) InHg. The relative standard deviation (RSD) was 2.7% (at 1 µg L(-1) InHg and n=10) calculated from the peak height of absorbance signals (Gaussian-shape and reproducible peaks). This work reports the first polymer-supported IL solid phase extraction approach implemented in a flow injection on-line system for determination of Hg species in mineral, tap and river water samples.

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Photocatalytic degradation of phenylmercury was studied using TiO2 in aqueous suspension assisted by UV-A irradiation. Reaction conditions, such as pH and amount of TiO2 were set using a factorial design of experiments resulting in a greater influence of pH on phenylmercury degradation. Hg (II) reduction and simultaneous oxidation of aromatic group was observed. Optimum reaction conditions were obtained under nitrogen atmosphere at pH 10 and 0.35 g/L(-1) TiO2. Under these conditions almost 100% reduction of mercury was reached after 30 min UV irradiation. Total mercury reduction was achieved after 40 min reaction under saturated oxygen. Furthermore, phenol and diphenylmercury were identified as intermediate products of oxidation. It was observed that a major fraction of the reduced mercury was removed as metallic vapor by gas stripping, whereas a minor fraction was adsorbed on the catalyst surface, probably as Hg(OH)2. Under optimal conditions obtained by multivariable analysis, total mineralization of organic matter was achieved after about 60-min irradiation.

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This paper describes a preconcentration method for Hg(2+) and MeHg(+) in water samples using sodium diethyldithiocarbamate immobilized in polyurethane foam (PU-NaDDC) and an extraction method for several mercury species in sediment samples, including MeHg(+), EtHg(+) and PhHg(+), which is simple, rapid, and uses a single organic solvent. Separation and measurement were done by high-performance liquid chromatography on-line with inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Initially, the test of recovery was applied using procedures compatible with HPLC. Under the optimum extraction conditions, recoveries of 96.7, 96.3 and 97.3% were obtained for MeHg(+), EtHg(+), and PhHg(+), respectively, from n=4 spiked sediment samples. This study also demonstrates that the combination of solid-phase extraction on PU-NaDDC with HPLC separation and ICP-MS detection is an effective preconcentration procedure for simultaneous measurement of Hg(2+) and MeHg(+) at ultra-trace levels in water samples. The application of the proposed procedure to the determination of mercury species in drinking water sample was investigated. The proposed method clearly gave satisfactory average recoveries between 93.7 and 101.5%.

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UV/TiO(2) photocatalysis of phenylmercury salts in aqueous solutions has been performed starting from both acetate (C(6)H(5)HgCH(3)CO(2), PMA) and chloride (C(6)H(5)HgCl, PMC) salts, in the presence or the absence of oxygen at acidic pH. Removal of Hg(II) in solution took place with the simultaneous deposit of dark or pale gray solids on the photocatalyst, identified as metallic Hg (when starting from PMA) or mixtures of Hg(0) and Hg(2)Cl(2) (when starting from PMC). Partial mineralization of the organic part of both compounds has also been achieved. Hg(II) removal and mineralization were enhanced in the absence of oxygen. PMA photocatalysis followed a saturation kinetics, going from first order at low concentration to zero order at higher concentrations (>0.5mM). For PMA, reaction was faster at high pH (11) with formation of mixtures of Hg and HgO. Phenol was detected as a product of the reaction in both cases, PMA and PMC, and no formation of dangerous methyl- or ethylmercury species was observed in the first case. A mechanism for the photocatalytic reaction has been proposed. The fact that calomel was found as a deposit when starting from PMC under nitrogen suggests that the mechanism of Hg(II) transformation proceeds through successive one-electron transfer reactions passing by mercurous forms.

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The mutans group of streptococci is considered to play a key role in the etiology of dental caries. We have evaluated the ability of different substances to prevent dental plaque formation without affecting Streptococcus sobrinus viability. Viable organisms were detected as CFU/mL in agar plates and bacterial adherence was assessed by dry weight. We studied 23 compounds and we demonstrated that phenyl salicylate, phenylmercuric nitrate and potassium iodate are more effective to inhibit adhesion without showing antibacterial activity.

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We have studied the effects of the sulfhydryl reagents on contractile responses, using either electrically stimulated single muscle fibers or short muscle fibers that were voltage-clamped with a two-microelectrode voltage-clamp technique that allows the fiber tension in response to membrane depolarization to be recorded. The sulfhydryl inhibitors para-chloromercuribenzoic acid (PCMB) and parahydroximercuriphenyl sulfonic acid (PHMPS), at concentrations from 0.5 to 2 mM, cause loss of the contractile ability; however, before this effect is completed, they change the fiber contractile behavior in a complex way. After relatively short exposure to the compounds, < 20 min, before the fibers lose their contractile capacity, secondary tension responses may appear after electrically elicited twitches or tetani. After losing their ability to contract in response to electrical stimulation, the fibers maintain their capacity to develop caffeine contractures, even after prolonged periods (120 min) of exposure to PHMPS. In fibers under voltage-clamp conditions, contractility is also lost; however, before this happens, long-lasting (i.e., minutes) episodes of spontaneous contractile activity may occur with the membrane polarized at -100 mV. After more prolonged exposure (> 30 min), the responses to membrane depolarization are reduced and eventually disappear. The agent DTT at a concentration of 2 mM appears to protect the fibers from the effects of PCMB and PHMPS. Furthermore, after loss of the contractile responses by the action of PCMB or PHMPS, addition of 2 mM DTT causes recovery of tension development capacity.

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A gret number of children (1507) were seriously affected by the use of diapers processed with phenylmercury acetate, in order to obtain bacteriostatic effect. The cytogenetic study was performed in 38 children whose age ranged from 1 month to 5 years. Sister chromatid exchange (SCE) was analysed in peripheral blood. The exposed children were classified in groups taking into account the period in which they were in touch with diapers and the time elapsed from the interruption of the diapers used until cytogenetic study. The value of SCE in the control group (presurgical children) was: Mean ñ SE = 5.9 ñ 0.6. Exposed children from 3 to 15 months with 9 months of interruption lapse of the use of diapers showed a significative increase in SCE frequency (Mean ñ SE = 7.9 ñ 1.8) respect to the group of children with a period of interruption was more than 9 months (Mean ñ SE = 5.9 ñ 0.9) and the controls (p < 0.001). This study suggests that the lymphocyte may be susceptible to phenyl-mercure acetate clastogenic effect. If the agent is clastogenic it may have carcinogenic effects the these children should be considered as a risk population

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Phenylmercury absorbed through the skin from contaminated diapers affected urinary excretion in infants in Buenos Aires. The effects were reversible and quantitatively related to the concentration of urinary mercury. Excretion of gamma-glutamyl transpeptidase, an enzyme in the brush borders of renal tubular cells, increased in a dose-dependent manner when mercury excretion exceeded a "threshold" value. Urine volume also increased but at a higher threshold with respect to mercury. The results support the threshold concept of the systemic toxicity of metals. gamma-Glutamyl transpeptidase is a useful and sensitive marker for preclinical effects of toxic metals.

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PIP: The incidence of sexually transmitted diseases (STD), especially gonorrhea, has risen dramatically in the past 2 decades. The population at greatest risk is also at high risk for unwanted pregnancies. Since currently employed treatment methods are failing to curb the problem, a search was instituted for an available vaginal contraceptive that would have a prophylactic effect against these diseases. In vitro studies have indicated that a vaginal contraceptive made of phenylmercuric acetate is an effective chemoprophylactic against Neisseria gonorrheae, Treponema pallidum, Candida albicans, Trichomonas vaginalis, and herpes simplex virus type 2. 2 clinical trials have shown that phenylmercuric acetate offered significant protection against gonorrheal infection. Although further testing is needed, the investigators concluded that phenylmercuric acetate was effective in reducing the incidence of gonorrheal infection and that the use of this agent could thus be of great value in combating a major health problem. The alarming increase in the incidence of STD throughout the world has resulted in a serious problem. The greatest increase has been in gonorrhea, with its incidence grown by 200% since 1958. Infections attributed to the other bacteria have also increased, although to a lesser extent. It is obvious that current treatment practices are failing to control the venereal disease epidemic. Considerable morbidity remains and the cost of combating these infections is high. Women with untreated gonococcal infections are at risk of developing salpingitis, with the possible sequelae of infertility due to tubal occlusion. This inability to bear children could be especially tragic as many of those who are at greatest risk are in their teens and early 20s. An agent which would provide both protection against these STD and contraceptive efficacy would be of great value. Since many of those in the high risk group do not have access to medical care, a vaginal contraceptive widely available without prescription would be likely to be used. This agent, made with phenylmercuric acetate is highly effective against these bacteria and trials have shown it to be good at reducing the incidence of gonorrheal infections in women. (author's)^ieng

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