顶空气相色谱-质谱法测定布南色林原料药中遗传毒性杂质

目的：建立顶空气相色谱-质谱法测定布南色林原料药中甲磺酸甲酯、甲磺酸乙酯和甲磺酸异丙酯3种遗传毒性杂质含量的方法。方法：采用顶空气相色谱-质谱法，以甲磺酸丁酯为内标，按内标标准曲线法进行甲磺酸甲酯、甲磺酸乙酯和甲磺酸异丙酯的含量测定。色谱条件：DB-WAX毛细管色谱柱（30 m×0.25 mm×0.25 μm）；程序升温，初始柱温为40℃，维持3 min，升温速率为30℃·min^-1，终止温度150℃，保持2 min；进样口温度为110℃；载气（He）流速为0.6 mL·min^-1；进样量为1 mL；进样方式为分流进样，分流比为20：1。质谱条件：电子轰击离子源（EI），扫描方式为选择性离子检测；离子源温度为200℃；接口温度为150℃；电子能量为70 eV；溶剂延迟1 min。结果：3种杂质成分之间的分离度均大于2.0；甲磺酸甲酯、甲磺酸乙酯、甲磺酸异丙酯检测质量浓度线性范围均为0.025~3.0 μg·mL^-1（r ≥ 0.998 5）；精密度、稳定性、重复性试验的RSD<5%；加样回收率分别为93.40%~101.40%（RSD为3.2%，n=9）、92.80%~99.70%（RSD为2.5%，n=9）和96.30%~100.75%（RSD为1.6%，n=9）。结论：该方法简便、准确、灵敏、迅速，可用于布南色林原料药中3种遗传毒性杂质的测定。     

Glutamate hypothesis in schizophrenia

Schizophrenia is a chronic and severe psychiatric disorder that has profound impact on an individual’s life and on society. Thus, developing more effective therapeutic interventions is essential. Over the past quarter‐century, an abundance of evidence from pharmacologic challenges, post‐mortem studies, brain imaging, and genetic studies supports the role of glutamatergic dysregulation in the pathophysiology of schizophrenia, and the results of recent randomized clinical trials based on this evidence have yielded promising results. In this article, we review the evidence that alterations in glutamatergic neurotransmission, especially focusing on the N‐methyl‐d ‐aspartate receptor (NMDAR) function, may be a critical causative feature of schizophrenia, how this contributes to pathologic circuit function in the brain, and how these insights are revealing whole new avenues for treatment development that could reduce treatment‐resistant symptoms, which account for persistent disability.     

Nano-curcumin therapy,a promising method in modulating inflammatory cytokines in COVID-19 patients

BackgroundAs an ongoing worldwide health issue, Coronavirus disease 2019 (COVID–19) has been causing serious complications, including pneumonia, acute respiratory distress syndrome (ARDS), and multi-organ failure. However, there is no decisive treatment approach available for this disorder, which is primarily attributed to the large amount of inflammatory cytokine production. We aimed to identify the effects of Nano-curcumin on the modulation of inflammatory cytokines in COVID-19 patients.MethodForty COVID-19 patients and 40 healthy controls were recruited and evaluated for inflammatory cytokine expression and secretion. Subsequently, COVID-19 patients were divided into two groups: 20 patients receiving Nano-curcumin and 20 patients as the placebo group. The mRNA expression and cytokine secretion levels of IL-1β, IL-6, TNF-α and IL‐18 were assessed by Real‐time PCR and ELISA, respectively.ResultOur primary results indicated that the mRNA expression and cytokine secretion of IL-1β, IL-6, TNF-α, and IL-18 were increased significantly in COVID-19 patients compared with healthy control group. After treatment with Nano-curcumin, a significant decrease in IL-6 expression and secretion in serum and in supernatant (P = 0.0003, 0.0038, and 0.0001, respectively) and IL-1β gene expression and secretion level in serum and supernatant (P = 0.0017, 0.0082, and 0.0041, respectively) was observed. However, IL-18 mRNA expression and TNF-α concentration were not influenced by Nano-curcumin.ConclusionNano-curcumin, as an anti-inflammatory herbal based agent, may be able to modulate the increased rate of inflammatory cytokines especially IL-1β and IL-6 mRNA expression and cytokine secretion in COVID-19 patients, which may cause an improvement in clinical manifestation and overall recovery.     

Methyl mercury: loaves versus fishes

Large numbers of individuals suffered severe neurological effects from poisoning with methyl mercury from the consumption of fish contaminated by industrial discharge in Minamata in the 1950s and 1960s and from bread made from fungicide-treated wheat in the early 1970s in Iraq. In both episodes, infants exposed in utero showed developmental delays. Data from Iraq permitted the estimation of dose-response relationships and provided evidence of greater sensitivity of the foetal brain compared to adult. Studies in a number of communities regularly consuming fish have sought to determine whether and at what level of prenatal exposure neurodevelopment defects may be detected, but the findings do not present a consistent picture. Benchmark analysis using data from Iraq and the three largest studies (New Zealand, Faroes, and Seychelles) suggest an overlap in estimated dose corresponding to a 10% increase in prevalence of adverse effects above background level. However, the Seychelles study, examining children up to 9 years of age, has not found a consistent pattern of adverse developmental effects; a possible explanation may be the presence of micronutrients in the ocean fish diet that enhance brain development and/or counter the toxic effects of methyl mercury.     

Principles of studying low-level neurotoxic exposures in children: using the Seychelles Child Development Study of methyl mercury as a prototype

Epidemiological studies to determine the impact of low level toxic exposure on child development are important in guiding clinical and public health action. However, carrying out such studies and interpreting their findings presents a number of significant challenges to the investigators. First, they must find a cohort with suitable exposure, select a biomarker that will accurately determine the level of exposure and determine the endpoints that are most likely to detect subtle differences in neurodevelopment. Following that, the logistics of the study must be organised and collaboration established with the local population and health authorities. To accurately interpret the data, they must also accurately determine covariates that impact child development. After the data are collected, interpreting the findings presents a further challenge. Throughout this process, the study must adhere to fundamental epidemiological principles and clearly defined statistical approaches. This paper discusses those principles and uses the Seychelles Child Development Study to show how one epidemiological study addressed them.     

The Seychelles Child Development Study of methyl mercury from fish consumption: analysis of subscales from the Child Behaviour Checklist at age 107 months in the main cohort

Methyl mercury (MeHg) is neurotoxic and all fish contain at least trace amounts. Consequently, prenatal or fetal exposure occurs when pregnant women consume fish and children are exposed postnatally when they breastfeed or consume fish. However, the level of exposure at which toxicity occurs is presently unknown. Since behavioural endpoints can be sensitive indicators of toxic exposure, we administered the Child Behaviour Checklist (CBCL) to measure behaviour as part of a prospective, longitudinal, double blind study (n = 779) of prenatal MeHg exposure, the Seychelles Child Development Study (SCDS). The CBCL Total T score was a primary endpoint at 66 and 107 month evaluations of the cohort and showed no association with prenatal or postnatal MeHg exposure. This paper reports the results of a secondary analysis of the CBCL subscales to see if specific aspects of behaviour might show associations. The SCDS main cohort was enrolled in 1989-90 and evaluated on five occasions through 107 months of age. The child's primary caregiver completed the CBCL at the 107 month evaluation. Prenatal exposure was determined by measuring total mercury (THg) in maternal hair growing during pregnancy and recent postnatal exposure by analysing the child's hair taken at the 107 month evaluation. Analysis included linear and nonlinear multiple regression models. For prenatal MeHg exposure, the Social Problems subscale was significantly associated and the Somatic Complaints subscale was marginally associated. Both were beneficial associations. For postnatal exposure the Thought Problems subscale was associated in an adverse direction. This secondary analysis identified a small number of subtle beneficial and adverse associations with prenatal and postnatal MeHg exposure for specific CBCL subscales. These analyses provide no evidence for an adverse effect of prenatal exposure. The adverse postnatal association is difficult to interpret because we measured only recent (about one month) exposure and no adjustment was made for the multiplicity of endpoints.     

Deciphering the role of Rhodnius prolixus CYP4G genes in straight and methyl‐branched hydrocarbon formation and in desiccation tolerance

Insect cuticle hydrocarbons are involved primarily in waterproofing the cuticle, but also participate in chemical communication and regulate the penetration of insecticides and microorganisms. The last step in insect hydrocarbon biosynthesis is carried out by an insect‐specific cytochrome P450 of the 4G subfamily (CYP4G). Two genes (CYP4G106 and CYP4G107) have been reported in the triatomines Rhodnius prolixus and Triatoma infestans. In this work, their molecular and functional characterization is carried out in R. prolixus, and their relevance to insect survival is assessed. Both genes are expressed almost exclusively in the integument and have an expression pattern dependent on the developmental stage and feeding status. CYP4G106 silencing diminished significantly the straight‐chain hydrocarbon production while a significant reduction – mostly of methyl‐branched chain hydrocarbons – was observed after CYP4G107 silencing. Molecular docking analyses using different aldehydes as hydrocarbon precursors predicted a better fit of straight‐chain aldehydes with CYP4G106 and methyl‐branched aldehydes with CYP4G107. Survival bioassays exposing the silenced insects to desiccation stress showed that CYP4G107 is determinant for the waterproofing properties of the R. prolixus cuticle. This is the first report on the in vivo specificity of two CYP4Gs to make mostly straight or methyl‐branched hydrocarbons, and also on their differential contribution to insect desiccation.     

Microspheres of essential oil in polylactic acid and poly(methyl methacrylate) matrices and their blends

This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains.

The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5–9.5?µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10?±?10.0?wt. % for PLA system and 76.0?±?3.3?wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same.     

Dibucaine in Ionic-Gradient Liposomes: Biophysical,Toxicological, and Activity Characterization

Administration of local anesthetics is one of the most effective pain control techniques for postoperative analgesia. However, anesthetic agents easily diffuse into the injection site, limiting the time of anesthesia. One approach to prolong analgesia is to entrap local anesthetic agents in nanostructured carriers (e.g., liposomes). Here, we report that using an ammonium sulphate gradient was the best strategy to improve the encapsulation (62.6%) of dibucaine (DBC) into liposomes. Light scattering and nanotracking analyses were used to characterize vesicle properties, such as, size, polydispersity, zeta potentials, and number. In vitro kinetic experiments revealed the sustained release of DBC (50% in 7 h) from the liposomes. In addition, in vitro (3T3 cells in culture) and in vivo (zebrafish) toxicity assays revealed that ionic-gradient liposomes were able to reduce DBC cyto/cardiotoxicity and morphological changes in zebrafish larvae. Moreover, the anesthesia time attained after infiltrative administration in mice was longer with encapsulated DBC (27 h) than that with free DBC (11 h), at 320 μM (0.012%), confirming it as a promising long-acting liposome formulation for parenteral drug administration of DBC.