Acquired methemoglobinemia in a third trimester puerpera and her premature infant with sodium nitrite poisoning:A case report

BACKGROUND The common cause of sodium nitrite poisoning has shifted from previous accidental intoxication by exposure or ingestion of contaminated water and food to recent alarming intentional intoxication as an employed method of suicide/exit.The subsequent formation of methemoglobin(MetHb)restricts oxygen transport and utilization in the body,resulting in functional hypoxia at the tissue level.In clinical practice,a mismatch of cyanotic appearance and oxygen partial pressure usually contributes to the identification of methemoglobinemia.Prompt recognition of characteristic mismatch and accurate diagnosis of sodium nitrite poisoning are prerequisites for the implementation of standardized systemic interventions.CASE SUMMARY A pregnant woman was admitted to the Department of Critical Care Medicine at the First Affiliated Hospital of Harbin Medical University due to consciousness disorders and drowsiness 2 h before admission.Subsequently,she developed vomiting and cyanotic skin.The woman underwent orotracheal intubation,invasive mechanical ventilation(IMV),and correction of internal environment disturbance in the ICU.Her premature infant was born with a higher-than-normal MetHb level of 3.3%,and received detoxification with methylene blue and vitamin C,supplemental vitamin K1,an infusion of fresh frozen plasma,as well as respiratory support via orotracheal intubation and IMV.On day 3 after admission,the puerpera regained consciousness,evacuated the IMV,and resumed enteral nutrition.She was then transferred to the maternity ward 24 h later.On day 7 after admission,the woman recovered and was discharged without any sequelae.CONCLUSION MetHb can cross through the placental barrier.Level of MetHb both reflects severity of the sodium nitrite poisoning and serves as feedback on therapeutic effectiveness.

Bone marrow-derived mesenchymal stem cells ameliorate sodium nitrite-induced hypoxic brain injury in a rat model

Sodium nitrite（Na NO2） is an inorganic salt used broadly in chemical industry. Na NO2 is highly reactive with hemoglobin causing hypoxia. Mesenchymal stem cells（MSCs） are capable of differentiating into a variety of tissue specific cells and MSC therapy is a potential method for improving brain functions. This work aims to investigate the possible therapeutic role of bone marrow-derived MSCs against Na NO2 induced hypoxic brain injury. Rats were divided into control group（treated for 3 or 6 weeks）, hypoxic（HP） group（subcutaneous injection of 35 mg/kg Na NO2 for 3 weeks to induce hypoxic brain injury）, HP recovery groups N-2 w R and N-3 w R（treated with the same dose of Na NO2 for 2 and 3 weeks respectively, followed by 4-week or 3-week self-recovery respectively）, and MSCs treated groups N-2 w SC and N-3 w SC（treated with the same dose of Na NO2 for 2 and 3 weeks respectively, followed by one injection of 2 × 106 MSCs via the tail vein in combination with 4 week self-recovery or intravenous injection of Na NO2 for 1 week in combination with 3 week self-recovery）. The levels of neurotransmitters（norepinephrine, dopamine, serotonin）, energy substances（adenosine monophosphate, adenosine diphosphate, adenosine triphosphate）, and oxidative stress markers（malondialdehyde, nitric oxide, 8-hydroxy-2′-deoxyguanosine, glutathione reduced form, and oxidized glutathione） in the frontal cortex and midbrain were measured using high performance liquid chromatography. At the same time, hematoxylin-eosin staining was performed to observe the pathological change of the injured brain tissue. Compared with HP group, pathological change of brain tissue was milder, the levels of malondialdehyde, nitric oxide, oxidized glutathione, 8-hydroxy-2′-deoxyguanosine, norepinephrine, serotonin, glutathione reduced form, and adenosine triphosphate in the frontal cortex and midbrain were significantly decreased, and glutathione reduced form/oxidized glutathione and adenosine monophosphate/adenosine triphosphate ratio were significantly increased in the MSCs treated groups. These findings suggest that bone marrow-derived MSCs exhibit neuroprotective effects against Na NO2-induced hypoxic brain injury through exerting anti-oxidative effects and providing energy to the brain.

Selective oxidation of biomass derived 5-hydroxymethylfurfural to 2,5-diformylfuran using sodium nitrite

A mild and simple process for the effective oxidation of 5-hydroxymethylfurfural（HMF） into 2,5-diformylfuran（DFF） has been developed using Na NO2 as the oxidant. Some important reaction parameters were investigated to optimize the oxidation of HMF into DFF. It was found that the reaction solvent was very crucial for this reaction. Trifluoroacetic acid was the best solvent for the oxidation of HMF into DFF by Na NO2.Under the optimal reaction condition, almost quantitative HMF conversion and high DFF yield of 90.4% were obtained after 1 h at room temperature.

Solvent extraction and separation of cobalt from leachate of spent lithium-ion battery cathodes with N263 in nitrite media

To effectively separate and recover Co(Ⅱ) from the leachate of spent lithium-ion battery cathodes,we investigated solvent extraction with quaternary ammonium salt N263 in the sodium nitrite system.NO_(2)^(-)combines with Co(Ⅱ) to form an anion [Co(NO_(2))_(3)]^(-),and it is then extracted by N263.The extraction of Co(Ⅱ) is related to the concentration of NO_(2)^(-).The extraction efficiency of Co(Ⅱ) reaches the maximum of99.16%,while the extraction efficiencies of Ni(Ⅱ),Mn(Ⅱ),and Li(Ⅰ) are 9.27%-9.80% under the following conditions:30vol% of N263 and15vol% of iso-propyl alcohol in sulfonated kerosene,the volume ratio of the aqueous-to-organic phase is 2:1,the extraction time is 30 min,and1 M sodium nitrite in 0.1 MHNO_(3).The theoretical stages require for the Co(Ⅱ) extraction are performed in the McCabe–Thiele diagram,and the extraction efficiency of Co(Ⅱ) reaches more than 99.00% after three-stage counter-current extraction with Co(Ⅱ) concentration of 2544mg/L.When the HCl concentration is 1.5 M,the volume ratio of the aqueous-to-organic phase is 1:1,the back-extraction efficiency of Co(Ⅱ)achieves 91.41%.After five extraction and back-extraction cycles,the Co(Ⅱ) extraction efficiency can still reach 93.89%.The Co(Ⅱ) extraction efficiency in the actual leaching solution reaches 100%.

Toxicity detection of sodium nitrite,borax and aluminum potassium sulfate using electrochemical method

Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an anaiyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose- glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions （solution pH 7.0, 37℃ and reaction for 3 hr）. The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be： sodium nitrite 〉 borax 〉 aluminum potassium sulfate 〉 blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives.

Synthesis of bis-ANS fluorescence probe in ionic liquids

A new application of ionic liquids in the preparation of fluorescence probe 5,51-bis-8-phenylamino-l-naphthylsulfonate （bisANS） is represented. The method for the preparation of fluorescence probe bis-ANS in alkyl imidazolium cationic liquids under acidic conditions is described. The effects on reaction yields under different concentration of sodium nitrite and different ionic liquid were studied and good yields were achieved.

A Gas Chromatography-Mass Spectrometry‑Based Metabonomic Study on Estimation of Toxicant in Rats

The aim of this study was to develop a gas chromatography‑mass spectrometry(GC‑MS)‑based metabolomics method to distinguish different kinds of poisons in the blood.We examined the changes in blood metabolites using GC‑MS following administration of four different poisons(paraquat,dichlorvos,aconitine,and sodium nitrite).The data were analyzed with orthogonal partial least squares.Then,total and single differential metabolite profiles were evaluated with support vector machine(SVM)models.The results showed that various metabolites(5‑ketone proline,1,5‑anhydrohexitol,lactic acid,glycine 2,2‑furoic acid,and 3‑hydroxybutyric acid)were differential between the experimental groups and the control groups.The accuracy rates of the SVM models established using total and single differential metabolites were 80%and 100%,respectively.In conclusion,we successfully developed a poison screening method.The established SVM models can distinguish four kinds of poisons and could be used to establish a complete poison metabonomic information database.Furthermore,some of the metabolites could be biomarkers of these poisons.Finally,both the models and potential biomarkers may reduce the time required for poison detection and provide direction for solving cases and auxiliary diagnosis.