Global mercury concentrations in biota: their use as a basis for a global biomonitoring framework.

An important provision of the Minamata Convention on Mercury is to monitor and evaluate the effectiveness of the adopted measures and its implementation. Here, we describe for the first time currently available biotic mercury (Hg) data on a global scale to improve the understanding of global efforts to reduce the impact of Hg pollution on people and the environment. Data from the peer-reviewed literature were compiled in the Global Biotic Mercury Synthesis (GBMS) database (>550,000 data points). These data provide a foundation for establishing a biomonitoring framework needed to track Hg concentrations in biota globally. We describe Hg exposure in the taxa identified by the Minamata Convention: fish, sea turtles, birds, and marine mammals. Based on the GBMS database, Hg concentrations are presented at relevant geographic scales for continents and oceanic basins. We identify some effective regional templates for monitoring methylmercury (MeHg) availability in the environment, but overall illustrate that there is a general lack of regional biomonitoring initiatives around the world, especially in Africa, Australia, Indo-Pacific, Middle East, and South Atlantic and Pacific Oceans. Temporal trend data for Hg in biota are generally limited. Ecologically sensitive sites (where biota have above average MeHg tissue concentrations) have been identified throughout the world. Efforts to model and quantify ecosystem sensitivity locally, regionally, and globally could help establish effective and efficient biomonitoring programs. We present a framework for a global Hg biomonitoring network that includes a three-step continental and oceanic approach to integrate existing biomonitoring efforts and prioritize filling regional data gaps linked with key Hg sources. We describe a standardized approach that builds on an evidence-based evaluation to assess the Minamata Convention's progress to reduce the impact of global Hg pollution on people and the environment.

Sensitive Detection of Nitrite and Nitrate in Seawater by 222 nm UV-Irradiated Photochemical Conversion to Peroxynitrite and Ion Chromatography-Luminol Chemiluminescence System.

Sensitive detection methods for nitrite (NO2-) and nitrate (NO3-) ions are essential to understand the nitrogen cycle and for environmental protection and public health. Herein, we report a detection method that combines ion-chromatographic separation of NO2- and NO3-, on-line photochemical conversion of these ions to peroxynitrite (ONOO-) by irradiation with a 222 nm excimer lamp, and chemiluminescence from the reaction between luminol and ONOO-. The detection limits for NO2- and NO3- were 0.01 and 0.03 µM, respectively, with linear ranges of 0.010-2.0 and 0.10-3.0 µM, respectively, at an injection volume of 1 µL. The results obtained by the proposed method for seawater analysis corresponded with those of a reference method (AutoAnalyzer based on the Griess reaction). As luminol chemiluminescence can measure ONOO- at picomolar concentrations, our method is expected to be able to detect NO2- and NO3- at picomolar concentrations owing to the high conversion ratio to ONOO- (>60%), assuming that contamination and background chemiluminescence issues can be resolved. This method has the potential to emerge as an innovative technology for NO2- and NO3- detection in various samples.

Development and optimization of a triple quadrupole ICP-MS-based system for the quantification of pre-concentrated gaseous elementary mercury.

Understanding the redox reactions and transformation rates of mercury (Hg) species in the environment is important for predicting future gaseous elemental Hg (Hg0) levels and assessing the impacts of anthropogenic Hg0 emissions on human health. Stable Hg isotope tracers are a promising tool for estimating Hg0 production rates; however, traditional analytical approaches for quantifying Hg0, such as atomic fluorescence spectroscopy or atomic absorption spectrometry, cannot differentiate between Hg isotopes, and alternative approaches, such as inductively coupled plasma mass spectrometry (ICP-MS) with a typical aqueous sample introductory system, have relatively higher detection limit of Hg. Here, we developed and evaluated a custom-made thermal desorption unit coupled directly to a triple quadrupole ICP-MS (ICP-QQQ) for the quantification of Hg0 pre-concentrated on Au traps. The performance of the system was validated with measurements of a Hg standard gas and of Hg0 generated from aqueous Hg standards. Using our system, we were able to detect ultra-trace amounts of Hg0 and obtain precise Hg isotope measurements with an analytical error of ≤ 3.5%. Calibration curves with superb linearity (r2 > 0.999) were obtained for the Hg concentration range of 0-300 pg. The method detection limit was approximately 0.01-0.03 pg of Hg. Using the latest ICP-QQQ instrument (Agilent 8900; Agilent Technologies Ltd.) was far superior to using a previous model (Agilent 8800), with the Agilent 8900 showing approximately five times higher sensitivity than the Agilent 8800 as well as the ability to precisely and simultaneously analyze up to five Hg isotopes by time-resolved analysis.

4G/5G Polymorphism of the plasminogen activator inhibitor-1 gene is associated with multiple organ dysfunction in critically ill patients.

OBJECTIVE: Impaired fibrinolysis is associated with a higher incidence of both multiple organ dysfunction and mortality in the intensive care unit (ICU). Plasminogen activator inhibitor (PAI)-1 is the chief inhibitor of fibrinolysis. We investigated the influence of the 4G/5G polymorphism (rs1799768) of the PAI-1 gene on the plasma PAI-1 level and the outcome of critically ill patients. METHODS: In 41 consecutive patients admitted to the ICU, PAI-1 gene polymorphism was assessed, plasma PAI-1 and arterial lactate concentrations were measured and clinical severity scores were recorded. RESULTS: Homozygotes for the 4G allele had higher plasma levels of PAI-1 antigen. The mean ± SD PAI-1 antigen level was 193.31 ± 167.93 ng/ml for the 4G/4G genotype, 100.67 ± 114.16 ng/ml for the 4G/5G genotype and 0.43 ± 0.53 ng/ml for the 5G/5G genotype. There was a significant correlation between plasma PAI-1 and arterial lactate concentrations, as well as between PAI-1 and severity scores. The mortality rate was 63, 33 and 0% for patients with the 4G/4G, 4G/5G and 5G/5G genotypes, respectively. CONCLUSIONS: These results demonstrate that the 4G/5G polymorphism of the PAI-1 gene affects the plasma PAI-1 concentration, which could impair fibrinolysis and cause organ failure, and thus the presence of the 4G allele increases the risk of death.

Nitrospina-like Bacteria Are Dominant Potential Mercury Methylators in Both the Oyashio and Kuroshio Regions of the Western North Pacific.

Highly neurotoxic methylmercury (MeHg) accumulates in marine organisms, thereby negatively affecting human and environmental health. Recent studies have revealed that oceanic prokaryotes harboring the hgcAB gene pair are involved in Hg methylation. Presently, little is known about the distribution and phylogeny of these genes in distinct oceanic regions of the western North Pacific. In this study, we used metagenomics to survey the distribution of hgcAB genes in the seawater columns of the subarctic Oyashio region and the subtropical Kuroshio region. The hgcAB genes were detected in the MeHg-rich offshore mesopelagic layers of both the Oyashio region, which is a highly productive area in the western North Pacific, and the Kuroshio region, which has low productivity. Comparative analysis revealed that hgcAB genes belonging to the Nitrospina-like lineage were dominant in the MeHg-rich mesopelagic layers of both regions. These results indicate that Nitrospina-like bacteria are the dominant Hg methylators in the mesopelagic layers throughout the western North Pacific. IMPORTANCE MeHg is highly neurotoxic and accumulates in marine organisms. Thus, understanding MeHg production in seawater is critical for environmental and human health. Recent studies have shown that microorganisms harboring mercury-methylating genes (hgcA and hgcB) are involved in MeHg production in several marine environments. Knowing the distribution and phylogeny of hgcAB genes in seawater columns can facilitate assessment of microbial MeHg production in the ocean. We report that hgcAB genes affiliated with the microaerophilic Nitrospina lineage were detected in the MeHg-rich mesopelagic layers of two hydrologically distinct oceanic regions of the western North Pacific. This finding facilitates understanding of the microbial Hg methylation and accumulation in seawater columns of the western North Pacific.

Nitrospina-Like Bacteria Are Potential Mercury Methylators in the Mesopelagic Zone in the East China Sea.

In natural environments, the production of neurotoxic and bioaccumulative methylmercury (MeHg) is mediated by microorganisms carrying the genes hgcA and hgcB. However, the contribution of these microorganisms to mercury (Hg) methylation or MeHg accumulation in the ocean is poorly understood. Here we determined the total Hg (THg) and MeHg concentrations in seawater samples and conducted a metagenomic survey of the hgcAB genes and functional modules involved in metabolic pathways in the East China Sea (ECS). In the metagenomic analyses, we used paired-end reads and assembled contigs for hgcAB enumeration and phylogenetic analyses in the seawater column. To evaluate the relative abundance of hgcAB in the metagenomic data, we estimated the abundance of recA (single-copy gene of bacteria) as well and then compared them. Moreover, the profiles of prokaryotic community composition were analyzed by 16S rRNA gene (V4 region) deep-sequencing. In the mesopelagic layers, the hgcA sequences were detected, and there was a positive correlation between hgcA abundance relative to the recA and MeHg concentrations. Thus, the quantification of the hgcA sequences could provide valuable information to evaluate the potential environments of microbial MeHg accumulation in the seawater column. A phylogenetic analysis using the assembled contigs revealed that all of the hgcA sequences in the mesopelagic layers were affiliated with Nitrospina-like sequences. The 16S rRNA gene analysis revealed that Nitrospinae were abundant in the mesopelagic layers. Although the lineages of Deltaproteobacteria, Firmicutes, and Spirochaetes were detected in the seawater column, their hgcAB sequences were not detected in our metagenomes, despite the fact that they are closely related to previously identified Hg methylators. The metabolic pathway analysis revealed that the modules related to sulfur and methane metabolism were prominent in the mesopelagic layers. However, no hgcA sequences affiliated with sulfate-reducing bacteria (SRB) or methanogens were detected in these layers, suggesting that these bacteria could not be strongly involved in the Hg accumulation in the seawater column. Our results indicate that Nitrospina-like bacteria with hgcAB genes could play a critical role in microbial Hg accumulation in the oxygenated mesopelagic layers of the ECS.

Before-after study of a restricted fluid infusion strategy for management of donor hepatectomy for living-donor liver transplantation.

PURPOSE: Intraoperative fluid infusion strategy remains controversial. Many animal model studies have shown that restricted fluid infusion reduces blood loss, though reports on this topic in humans are rare. The purpose of this study was to determine the effects on volume of blood loss of a restricted fluid infusion strategy for hepatectomy in donors for living donor liver transplantation. METHODS: A before-after study design was used with prospective consecutive data collection. A total of 22 patients who underwent living-donor hepatectomy were enrolled. Eleven patients who were managed before the implementation of restricted-volume fluid administration comprised the standard-volume group, and 11 who were evaluated after the implementation of the restricted-volume infusion strategy comprised the restricted-volume group. In the standard-volume group, the donors were given 10 ml x kg(-1) x h(-1) of lactated Ringer's solution and additional plasma expander corresponding to blood loss. In the restricted-volume group, the donors received 5 ml x kg(-1) x h(-1) of lactated Ringer's solution until the resection of the hepatic graft, followed by 15 ml x kg(-1) x h(-1) of lactated Ringer's solution after the completion of resection until the end of the operation. RESULTS: Intraoperative blood loss was less in the restricted-volume group (445 +/- 193 ml) than in the standard-volume group (1331 +/- 602 ml; P < 0.01). Intraoperative fluid infusion was also less in the restricted-volume group (4130 +/- 563 ml) than in the standard-volume group (5634 +/- 1260 ml; P < 0.01). There were no differences in length of hospital stay or side effects between the two groups. CONCLUSION: Our restricted-volume strategy reduced blood loss and had no adverse effects during living-donor hepatectomy.

A simple, lightweight CPAP-delivery device, composed of a three-way stopcock, for the nondependent lung.

PURPOSE: We aimed to introduce a simple, lightweight continuous positive airway pressure (CPAP)-delivery device for the nondependent lung during one-lung ventilation, to investigate how the type of three-way stopcocks, and the compliance and resistance of a test lung affect the relationship between the oxygen flow rate and CPAP level produced, and to examine how the device works in a clinical setting. METHODS: In the test lung study, the bronchial blocker of a Univent tube was connected to a test lung. The effects of oxygen-flow rate, types of three-way stopcocks, and compliance and resistance of the test lung on the CPAP levels were studied. In the clinical study, the lightweight device was used to treat hypoxia in seven patients during one-lung ventilation with the bronchial blocker. RESULTS: In the test lung study, the CPAP level produced by the device was proportional to the oxygen-flow rate, dependent on the type of three-way stopcock used, and independent of the compliance or resistance of the test lung. There was no discrepancy between the plateau pressures of the test lung and the monitoring port of an additional stopcock at any degree of compliance or resistance of the test lung at any oxygen-flow rate. Therefore, the relationship between the oxygen-flow rate and CPAP level can be ensured in advance before application to the lung, with an additional three-way stopcock of which the distal end is occluded. In the clinical study, peripheral oxygen sataration Sp(O2) improved while the CPAP level ranged from 2.8 to 5.4 cmH2O. CONCLUSION: The lightweight CPAP delivery-device can provide variable CPAP levels by adjusting the oxygen-flow rate without real-time monitoring of the pressure.

Skin-traction method prevents the collapse of the internal jugular vein caused by an ultrasound probe in real-time ultrasound-assisted guidance.

PURPOSE: Real-time ultrasound-assisted guidance for catheterization of the internal jugular vein (IJV) is known to be useful, especially for a small-sized vein, which is difficult to catheterize. However, one of the problems with real-time ultrasound-assisted guidance is that the ultrasound probe itself can collapse the vein. We have developed a novel "skintraction method (STM)", in which the puncture point of the skin over the IJV is stretched upwards with several pieces of surgical tape in the cephalad and caudal directions with the aim being to facilitate catheterization of the IJV. We examined whether this method increased the compressive force required to collapse the IJV. METHODS: In ten volunteers, the compressive force required to collapse the right IJV, and the cross-sectional area and anteroposterior and transverse diameters of the IJV were measured with ultrasound imaging in the supine position (SP) with or without the STM or in the Trendelenburg position of 10 degrees head-down (TP) without the STM. RESULTS: The compressive force to required to collapse the vein was increased significantly with the STM, while the crosssectional area and anteroposterior diameter of the vein in the SP with STM were similar to those in the TP without the STM. CONCLUSION: With the STM, not only the cross-sectional area but also the compressive force required to collapse the IJV increased. Thus, the STM may facilitate real-time ultrasoundassisted guidance for catheterization of the IJV by maintaining the cross-sectional area of the vein during the guidance.

Three decades of environmental specimen banking at the National Institute for Environmental Studies, Japan.

After two decades operation of the initial environmental specimen banking, a new program, Environmental Time Capsule Program, started in 2002 as a government-supported long-term program to construct a firm scientific basis for various environmental research studies. The program consists of long-term environmental specimen banking activity and specimen collection of endangered wildlife and is based on cryogenic sample preservation facility called Environmental Time Capsule building, which completed construction in 2004. After 9 years of extensive research, research focuses have been selected and the program was reorganized to the environmental sample collection part and endangered wildlife collection part in 2011. Due to huge environmental disaster caused by the Great East Japan earthquake and the tsunami as well as subsequent nuclear power plant accident at Fukushima, a new sampling and monitoring program started at affected areas in collaboration with the reorganized environmental sample collection and archiving program. Outlines of the quality assurance and quality control (QA/QC) activities in the program and future perspective under related international activities, particularly Stockholm Convention, are reported.

Effect of mild hypothermia on the expression of aquaporin family in cultured rat astrocytes under hypoxic condition.

Aquaporins (AQPs) are a family of water-selective transporting proteins with homology to the major intrinsic protein (MIP) of lens, that increase plasma membrane water permeability in secretory and absorptive cells. In this study, we investigated the effect of mild hypothermia on the expression of AQP4, AQP5 and AQP9 in rat astrocytes cultured under hypoxic conditions. At 37 degrees C, a marked decrease in the expression of AQP4, AQP5 and AQP9 mRNAs was observed. However, at 32 degrees C (mild hypothermia), the expression of AQP5 mRNA was restored to its basal level. Interestingly, under mild hypothermia AQP4 mRNA expression transiently decreased and then increased about two-fold; while AQP9 mRNA expression decreased the same as at 37 degrees C. The changes in the expression of AQP4 and AQP9 proteins were confirmed by Western blot analysis. The restoration of the AQP4 and AQP5 expression at 32 degrees C from the hypoxia-induced decrease at 37 degrees C may play an important role in the reduction of brain edema under hypothermic conditions.

Status of Red Stingray (Dasyatis akajei) Livers for Japanese Specimen Banking at National Institute for Environmental Studies, Unscathed by the 2011 Tohoku Earthquake.

It is important to have a resource of environmental specimens in order to investigate changes in contaminant exposure and accumulation over time. At the National Institute for Environmental Studies in Japan, red stingray livers have been archived and the banking activity has expanded successfully since 2003. The developed standard operating procedure helps to maintain quality of the archived homogenized liver samples, and the risk management plan has helped to prevent thawing them from any incidents, including the catastrophic 2011 Tohoku earthquake. The cryogenically homogenized powdered livers will be stored in a cryogenic environment in liquid nitrogen vapor containers at -160 °C and will be analyzed when new pollutants are identified in the future.

Flavopiridol inhibits interferon-γ-induced nitric oxide production in mouse vascular endothelial cells.

Flavopiridol (FP), a synthetic flavone, is a cyclin-dependent kinase inhibitor and possesses an anti-cancer activity. The effect of FP on interferon (IFN)-γ-induced nitric oxide (NO) production in mouse vascular endothelial cell line END-D was examined. FP significantly inhibited IFN-γ-induced NO production in END-D cells via reduced expression of an inducible NO synthase. FP inhibited the activation of STAT1, and subsequently IRF1 as a downstream molecule of STAT1, which is essential for IFN-γ-induced NO production. FP did not affect the cell surface expression of IFN-γ receptor. Taken together, FP was suggested to inhibit IFN-γ-induced NO production in vascular endothelial cells via preventing intracellular IFN-γ signaling. FP might be useful as an immunomodulatory drug as well as an anti-cancer drug.

Cardiac output increases the rate of carbon monoxide elimination in hyperpneic but not normally ventilated dogs.

PURPOSE: The very high solubility of carbon monoxide (CO) in blood suggests that its elimination depends predominantly on ventilation and not perfusion. Nevertheless, hyperventilation is not used for CO elimination because of the adverse effects of hypocapnia. With isocapnic hyperpnea (IH), ventilation can be increased considerably without hypocapnia. This raises the issue of whether CO elimination is limited by perfusion during IH. We studied the effect of increasing cardiac output on t1/2, the half-time of decline of blood carboxyhemoglobin concentration ([COHb]), during normal ventilation (NV) and during IH. METHODS: After ethics approval was received, 13 pentobarbital-anesthetized ventilated dogs were exposed to CO to increase their [COHb]. They were then ventilated with NV or IH. At each level of ventilation, dogs were randomly assigned to treatment with dobutamine (to increase cardiac output) or to no dobutamine treatment. After the return of [COHb] to control levels, each dog was re-exposed to CO and treated with the same ventilatory mode, but the alternative inotropic treatment. RESULTS: Gas exchange, [COHb], and hemodynamic measures were recorded during the study. Cardiac index values in the IH group were 4.1 +/- 0.5 and 8.2 +/- 1.2 l.min(-1).m(-2) without and with dobutamine infusion, respectively. Dobutamine infusion was associated with a reduction in t1/2 from 20.3 +/- 3.6 to 16.9 +/- 2.4 min (P = 0.005) in the IH group, but no change in the NV group. CONCLUSION: These findings suggest that CO elimination during IH treatment is limited at least partly by pulmonary blood flow and may therefore be further augmented by increasing cardiac output.

Postextubation airway management with nasal continuous positive airway pressure in a child with Down syndrome.

We describe our experience with use of variable-flow nasal continuous positive airway pressure (NCPAP) to manage postextubation stridor in a 31-month-old child with Down syndrome (DS). Although it has been recognized that children with DS tend to develop obstruction of the upper airway postoperatively, little is known concerning appropriate management of this situation. Although there are surprisingly few reports of use of variable-flow NCPAP for children older than preterm infants, we successfully treated postextubation ventilatory complications by providing variable-flow NCPAP without complications such as pneumothorax.

Inadvertent intrathecal cannulation in an infant, demonstrated by three-dimensional computed tomography: a rare complication of internal jugular vein catheterization.

We describe a case of inadvertent intrathecal cannulation with a central venous catheter in an infant, confirmed by three-dimensional computed tomography, which clearly demonstrated the track of the catheter. We believe that this complication could have been related to two major factors: depth of needle insertion and penetration of the vein by a straight-tip guidewire. To avoid this complication, the depth of needle insertion must be carefully checked, a "J"-tipped rather than a straight-tipped guidewire should be used, and puncture should be guided by ultrasound.

Anesthetic and airway management of general anesthesia in a patient with Meckel-Gruber syndrome.

Meckel-Gruber syndrome, characterized by occipital encephalocele, microcephaly, polydactyly, cleft lip or palate, mandibular micrognathism, and anatomical abnormality of the larynx and tongue, along with other associated malformations, is in the list of diseases associated with difficult airway. However, there has been no report on the management of general anesthesia and airway management for such patients. A 2-year-old girl with Meckel-Gruber syndrome was scheduled for cardioplasty and gastrostomy for gastroesophageal reflux under general anesthesia. Preoperative examination revealed obesity, microgenia, dysspondylism, proteinuria, hypoplastic kidneys, and stenosis of the anal canal. Although we anticipated some difficulty with the intubation and prepared several alternative methods for intubation, such as a bronchofiberscope and a laryngeal mask airway, tracheal intubation was completed without difficulty using conventional laryngoscopy after inhalational induction with sevoflurane. Because most patients with this syndrome die before and shortly after delivery, those who survive to some age might have less severe deformities.

Normocapnia improves cerebral oxygen delivery during conventional oxygen therapy in carbon monoxide-exposed research subjects.

STUDY OBJECTIVE: We determine whether maintaining normocapnia during hyperoxic treatment of carbon monoxide-exposed research subjects improves cerebral oxygen delivery. METHODS: This experiment used a randomized, single-blinded, crossover design. We exposed 14 human research subjects to carbon monoxide until their carboxyhemoglobin levels reached 10% to 12%. We then treated each research subject with 60 minutes of hyperoxia with or without normocapnia. Research subjects returned after at least 24 hours, were reexposed to carbon monoxide, and were given the alternate treatment. Relative changes in cerebral oxygen delivery were calculated as the product of blood oxygen content and middle cerebral artery velocity (an index of cerebral blood flow) as measured by transcranial Doppler ultrasonography. RESULTS: Maintaining normocapnia during hyperoxic treatment resulted in significantly higher cerebral oxygen delivery compared with standard oxygen treatment (P <.05; 95% confidence interval at 60 minutes 2.8% to 16.7%) as a result of the prevention of hypocapnia-induced cerebral vasoconstriction and more rapid elimination of carbon monoxide due to increased minute ventilation. CONCLUSION: If severely poisoned patients respond like our research subjects, maintaining normocapnia during initial hyperoxic treatment of carbon monoxide poisoning may lead to increased oxygen delivery to the brain. Determining the effect of such a change in conventional treatment on outcome requires clinical studies.