Characteristics of compounds with strong or weak nitrification inhibition in sewage

To clarify the characteristics of compounds with strong or weak nitrification inhibition in sewage, 64 organic compounds including compounds registered in Pollutant Release and Transfer Register (PRTR) were evaluated in terms of their chemical structures and molecular weights. Nineteen compounds showed strong nitrification inhibition by testing with Nitrosomonas europaea. Compounds with thioamide structures had the lowest median value of EC50 (0.017 mg/L), followed by those with alkyne structures (0.121 mg/L), chlorophenol structures (0.300 mg/L), and then azole structures (0.365 mg/L). In contrast, 33 of the 64 compounds showed weak nitrification inhibition at a concentration of 10 mg/L, 27 of which were categorized into three main groups: long-chain alcohol structures, alkyne structures with a phenyl group, and aromatic structures. Most compounds with strong nitrification inhibition had a low molecular weight (MW) from 50 to 200. Meanwhile, the proportion of compounds with weak nitrification inhibition tended to be greater with increasing MW and such compounds were predominant at higher molecular weights above 300. The correlations of results derived from tests of nitrification inhibition based on ISO 9509 and N. europaea showed that 24 out of 30 compounds provided results that were highly correlated between these tests (R = 0.85), while 4 compounds with chlorophenol structures and 2 compounds with alkyne structures showed weaker inhibition rates in the ISO 9509 test than in the N. europaea test. Our results indicate that the magnitude of nitrification inhibition depends on MW in addition to the chemical structure, which is helpful in the search for the cause of nitrification inhibition in wastewater treatment plants.

Summary of reference chemicals evaluated by the fish short-term reproduction assay, OECD TG229, using Japanese Medaka, Oryzias latipes

Under the Organisation for Economic Co-operation and Development (OECD), the Ministry of the Environment of Japan (MOE) added Japanese medaka (Oryzias latipes) to the test guideline fish short-term reproduction assay (FSTRA) developed by the United States Environmental Protection Agency (US EPA) using fathead minnow (Pimephales promelas). The FSTRA was designed to detect endocrine disrupting effects of chemicals interacting with the hypothalamic-pituitary-gonadal axis (HPG axis) such as agonists or antagonists on the estrogen receptor (Esr) and/or the androgen receptor (AR) and steroidogenesis inhibitors. We conducted the FSTRA with Japanese medaka, in accordance with OECD test guideline number 229 (TG229), for 16 chemicals including four Esr agonists, two Esr antagonists, three AR agonists, two AR antagonists, two steroidogenesis inhibitors, two progesterone receptor agonists, and a negative substance, and evaluated the usability and the validity of the FSTRA (TG229) protocol. In addition, in vitro reporter gene assays (RGAs) using Esr1 and ARβ of Japanese medaka were performed for the 16 chemicals, to support the interpretation of the in vivo effects observed in the FSTRA. In the present study, all the test chemicals, except an antiandrogenic chemical and a weak Esr agonist, significantly reduced the reproductive status of the test fish, that is, fecundity or fertility, at concentrations where no overt toxicity was observed. Moreover, vitellogenin (VTG) induction in males and formation of secondary sex characteristics (SSC), papillary processes on the anal fin, in females was sensitive endpoints to Esr and AR agonistic effects, respectively, and might be indicators of the effect concentrations in long-term exposure. Overall, it is suggested that the in vivo FSTRA supported by in vitro RGA data can adequately detect effects on the test fish, O. latipes, and probably identify the mode of action (MOA) of the chemicals tested.

Utility of transcranial color flow imaging for detecting high risk morphology of patent foramen ovale in patients with cerebral infarction

Background

Micro-bubble test by using transcranial color flow imaging (TCCFI) is important as a screening evaluation for diagnosis of paradoxical cerebral embolism which requires the proof of right to left shunt at atrial septum. In addition, high risk features of patent foramen ovale (PFO) that may allow thrombus to easily pass through the PFO itself were previously reported. However, little is known about the association between the degrees on micro-bubble test by TCCFI and the features of high risk PFO.

Purpose

Our aim is to clarify the relationship between the degree of micro-bubble test in TCCFI and the morphology of PFO from transesophageal echocardiography (TEE).

Methods

Seventy-seven patients in whom cardiogenic embolism was strongly suspected by neurologists in Showa University from April to December in 2019 were retrospectively studied. 55 patients underwent both TCCFI and TEE with sufficient Valsalva stress. TCCFI grade of micro-bubble test was classified into 3 groups (A: none, B: small, and C: massive), in which signified “none” is no sign of micro-embolic signals (MES) within 30 seconds, “small” is 1 or more MES, and “massive” is so much MES look like a curtain (Figure). Evaluated high risk characteristics of PFO for cerebral embolism as previously reported were as follows; (1) tunnel height, (2) tunnel length, (3) total excursion distance into right and left atrium, (4) existence of Eustachian valve or Chiari network, (6) angle of PFO from inferior vena cava (7) large shunt (20 or more micro-bubbles).

Results

Of all TCCFI-positive patients (n=32; Group B=19, Group C=13) with cerebral embolism, PFOs were detected in 23 patients in TEE. Therefore, the sensitivity and specificity of TCCFI to PFO were 87% and 63% (AUC=0.75, p<0.001, respectively). Interestingly, all 13 patients (Group C) had manifest PFOs. Moreover, group C include 2 patients with platypnea orthodeoxia syndrome in which hypoxia in the sitting position becomes apparent. Among PFO-positive patients, tunnel height, length, total excursion distance into right and left atrium, and large shunt in TEE were significantly larger in Group C than Group B (p<0.05).

Conclusions

Micro-bubble test by using TCCFI may have screening advantages in predicting paradoxical cerebral embolism, high-risk morphology of PFO, and platypnea orthodeoxia syndrome.

Figure 1

Funding Acknowledgement

Type of funding source: None

[Effect sites of anesthetics in the central nervous system network--looking into the mechanisms for natural sleep and anesthesia]

We showed the effect sites of anesthetics in the central nervous system (CNS) network. The thalamus is a key factor for loss of consciousness during natural sleep and anesthesia. Although the linkages among neurons within the CNS network in natural sleep are complicated, but sophisticated, the sleep mechanism has been gradually unraveled. Anesthesia disrupts the link-ages between cortical and thalamic neurons and among the cortical neurons, and thus it loses the integration of information derived from the arousal and sleep nuclei. It has been considered that anesthesia does not share the common pathway as natural sleep at the level of unconsciousness, because anesthetics have multiple effect sites within CNS network and may induce disintegration among neurons. Recent literatures have shown that the effects of anesthetics are specific rather than global in the brain. It is interesting to note that thalamic injection of anti-potassium channel materials restored consciousness during inhalation anesthesia, and that the sedative components of certain intravenous anesthesia may share the same pathway as natural sleep. To explore the sensitivity and susceptibility loci for anesthetics in the thalamocortical neurons as well as arousal and sleep nuclei within CNS network may be an important task for future study.

Application of a larval medaka assay to evaluate the fish safety level in Sagami River, Japan

Despite of the increasing concern on aquatic life preservation from water pollution, few methods are available to evaluate the fish safety level of river water. In this study, a principal urban river of Japan, Sagami River, was investigated the geographical and seasonal changes in the fish safety level using an efficient larval medaka (Oryzias latipes) assay. Then combined with topography and land-use character of the catchment, the influence of human activity was discussed. The results revealed the highest fish safety levels and the lowest dissolved organic carbon (DOC) concentrations in the preserved region of the upstream. In the lower mainstream and the west tributaries, catchments of which were developed regions with high sewerage diffusion rates, the fish safety levels slightly decreased although the DOC concentrations were low. By comparison, the east tributaries, which were allocated in highly developed regions without sufficient sewerage service, showed not only high DOC concentrations but also greatly decreased fish safety levels. Two small east tributaries showed three to four times increase in the toxicity in winter, as influenced by the irrigation activity on the bank. The safety level did not closely depend on the common water quality indicator of DOC, although extremely high DOC concentrations tended to relate to low safety levels. The data is useful for better management of the river studied, and the approaches used in this paper will give a hint to the management of other rivers.

BRAF mutation predicts MEK-dependence in non-small cell lung cancer (NSCLC)

10523

Background: Constitutive ERK signaling is common in human cancer and is often the result of activating mutations in BRAF, RAS and upstream receptors. Missense BRAF kinase domain mutations are frequently observed in melanoma, colon and thyroid cancers and less frequently in lung and other cancer types. The vast majority (>90%) involve a glutamic acid for valine substitution at codon 600 (V600E), which results in elevated BRAF kinase activity. BRAF kinase domain mutations with intermediate and impaired kinase activity have also been identified, most frequently in NSCLC. We have previously reported that tumors with V600E BRAF mutation are selectively sensitive to MEK inhibition. Methods: Using the potent and selective MEK1/2 inhibitor PD0325901 (Pfizer), we examined a panel of NSCLC cell lines with mutant EGFR, KRAS, and/or low, intermediate and high-activity BRAF kinase domain mutations, with regard to MEK dependence. In all but one case, EGFR, KRAS and BRAF mutations were mutually exclusive. Results: Consistent with our prior results, NSCLC cells with V600E BRAF mutation were exquisitely sensitive to MEK inhibition (PD0325901 IC50 of 2nM). The proliferation of cells with non-V600E mutations, including those with high (G469A), intermediate (L597V) and impaired (G466V) kinase activities, was also MEK dependent with IC50's ranging between 2.7 and 80 nM. Inhibition of MEK in these cells resulted in downregulation of cyclin D1 and G1 growth arrest, with variable induction of apoptosis. Despite high basal ERK activity, NSCLC tumor cells with EGFR mutation were uniformly resistant to MEK inhibition (at doses of up to 500nM), despite effective inhibition of ERK phosphorylation. Tumor cells with RAS mutation had a more variable response, with some cell lines demonstrating sensitivity, while others were completely resistant. There was no correlation between basal ERK activity and sensitivity to MEK inhibition. A strong inverse correlation between AKT phosphorylation/ activity and PD0325901 sensitivity was observed. Conclusions: These results suggest that MEK inhibition may be useful therapeutically in tumors with V600E and non-V600E BRAF kinase domain mutations. The results also suggest that inhibition of both MEK and AKT signaling may be required in NSCLC tumors with high basal AKT activity.

No significant financial relationships to disclose.

Evaluating the fish safety level of river water and wastewater with a larval medaka assay

A larval medaka (Oryzias latipes) assay was proposed to evaluate the fish safety level of river waters and wastewaters. Organic toxicants were 10-100 times concentrated with adsorption cartridges from 4 l of river water or 1-10 times concentrated from 400 ml of wastewater. Toxicity of these concentrated solutions was determined by exposing 48-72 h post-hatch age larvae for 48 h. The method effectively revealed a variation of the median lethal concentration ratio (LCR50) from 13 to >100 in 125 river water samples, and from <1 to >10 in five typical wastewater samples. Ayase River, which takes water mostly from agricultural or household discharge, showed significantly (P<0.001) lower LCR50 than Sagami River that takes natural water as the source. Safety Levels in both Sagami River and Ayase River were influenced by the irrigation activity, LCR50 at some sites showing a seasonal-specific decrease in winter. Pollution from pulp and paper industries contributed to the low LCR50 in several tributaries of Ayase River. Required little manpower in sampling, pretreatment and testing, the proposed larval medaka assay was proved as an efficient tool for screening those high risk sites for priority management.

V600E B-Raf requires the Hsp90 chaperone for stability and is degraded in response to Hsp90 inhibitors

The Raf family includes three members, of which B-Raf is frequently mutated in melanoma and other tumors. We show that Raf-1 and A-Raf require Hsp90 for stability, whereas B-Raf does not. In contrast, mutated, activated B-Raf binds to an Hsp90-cdc37 complex, which is required for its stability and function. Exposure of melanoma cells and tumors to the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin results in the degradation of mutant B-Raf, inhibition of mitogen-activated protein kinase activation and cell proliferation, induction of apoptosis, and antitumor activity. These data suggest that activated mutated B-Raf proteins are incompetent for folding in the absence of Hsp90, thus suggesting that the chaperone is required for the clonal evolution of melanomas and other tumors that depend on this mutation. Hsp90 inhibition represents a therapeutic strategy for the treatment of melanoma.

A larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction to efficiently determine the toxicity of organic contaminants in river water

Using a larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction, we proposed a method for efficiently determining the fish toxicity of organic contaminants in river water. Organic toxicants were 10, 20, 50 and 100-fold concentrated from 4 L of the sample with adsorption cartridges. The lethal effect was observed by exposing every ten individuals of 48-72 h old larval medaka to 20 mL of each solution for 48h. The median lethal concentration rate (LCR50) was used as an indicator for the toxicity. With the developed toxicity test method, more than seven times difference was found in the LCR50 of the river water samples. LCR50 distribution profiles were compared with 125 samples in two typical rivers. The result revealed a lower toxicity level in the mainstream than in the confluences, and a lower toxicity level in Sagami River than in Ayase River. LCR50 proved unique as a toxicity indicator, which was impossible to speculate from the conventional water quality indicator of the dissolved organic carbon concentration. As an effective screening test for priority settings, the method can help us with an efficient planning for the environmental investigation and management.