The Role Of Electro-Physiological Tests in the Diagnosis of Non-Organic Hearing Loss

Today it is possible, by the use of newly developed tests, to diagnose cases of non-organic hearing loss with reasonable certainty. Having once decided that there may be non-organic elements, it is useful to supplement routine pure-tone and speech audiometry with a neurophysiological test like an ERA by means of which the auditory threshold can be established without the patients subjective judgement. A hearing loss which is apparent by routine pure-tone audiometry, but which is not evident after ERA is almost certainly non-organic, although confirmation of this state of affairs by other reliable tests is advisable. Measurement of the acoustic reflex thresholds and delayed speech feedback tests are both useful in this respect and rarely cause any confusion, except in some cases of true hearing loss in strongly recruiting ears.     

检测乙酰胆碱酯酶的双光子荧光探针的设计、合成及生物学评价

目的 设计并合成用于检测乙酰胆碱酯酶（acetylcholinesterase，AChE）的双光子荧光探针，并考察探针对AChE的成像检测性能。方法 经酯化、取代等多步有机反应合成探针，并通过¹H-NMR、¹³C-NMR和ESI-MS确认结构。考察探针与AChE发生响应后的荧光信噪比、灵敏度、特异性、酶动力学和双关子吸收截面积数值等指标；研究探针可否用于AChE抑制剂的体外筛选；利用单-双光子成像试验考察探针在细胞和组织水平上对AChE活力变化的检测能力。结果 通过¹H-NMR、¹³C-NMR和ESI-MS确认了产物的结构。体外试验表明探针与AChE响应后的荧光信噪比为15倍，检测限达到0.23 U·mL^–1，并具有很强的特异性和优良的酶亲合能力，在波长820 nm有最优的双光子吸收；探针可用于AChE抑制剂的体外筛选；探针通过单-双光子成像技术可对细胞和组织水平上的AChE活力变化进行成像检测，并且组织成像检测深度可达110 μm。结论 本研究成功开发了可用于AChE检测的双光子荧光探针，有潜力成为可用于活体中检测AChE活力的双光子成像试剂。     

卡培他滨中有机残留溶剂的检测

目的建立气相色谱法测定卡培他滨原料药中二氯甲烷、乙醇、甲醇和乙酸乙酯4种有机溶剂。方法采用DB-624毛细管柱,FID检测器,以DMSO为溶剂。结果各有机溶剂的平均加样回收率为93.7%～97.6%,RSD为2.5%～3.7%。结论该方法稳定准确,可用于卡培他滨中有机溶剂残留的检测。     

Recent Chemical Exposures and Blood Volatile Organic Compound Levels in a Large Population-Based Sample

Little is known about factors that influence blood levels of volatile organic compounds in nonoccupationally exposed populations. The authors examined the possible relationship between recent self-reported chemical exposures and elevated blood volatile organic compound levels among 982 adult participants in the Third National Health and Nutrition Examination Survey. A strong dose-response effect was indicated (p < .001) for increasing lifetime pack-years of cigarettes smoked for elevated levels of toluene, styrene, and benzene. A positive dose-response effect was indicated for daily alcohol consumption with respect to elevated blood levels of 2-butanone and acetone. For volatile organic compounds typically found in 10-75% of the population, the establishment of a link with specific environmental exposures is relatively easy because there is less effect of confounding in this group. Some volatile organic compounds, however, are seen in less than 10% of the general population; finding these compounds at any level may warrant a search for a particular exposure.     

A new antioxidant compound from Capparis spinosa

An activity-directed fractionation and purification process was used to isolate 1,1-diphenyl-2-picrylhydrazyl radical (DPPH?) scavenging components from fruits of Capparis spinosa L. (Capparaeae). Ethyl acetate and aqueous fractions showed greater DPPH? scavenging activities compared to the petroleum ether fractions. The ethyl acetate fraction was subjected to purification using column chromatography. A new antioxidant cappariside (4-hydroxy-5-methylfuran-3-carboxylic acid, 1), together with seven known organic acids (2–8) for the first time from plants of genus Capparis and four known organic acids (9–12) were isolated from C. spinosa. The structures were elucidated by extensive analysis of 1D- and 2D-NMR spectroscopic. In addition, compounds 1, 2, 4, 5, 9, 10 and 12 indicated strong scavenging capacity for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals with a SC₅₀ value of 0.204?±?0.002, 0.007?±?0.0, 0.011?±?0.0, 0.044?±?0.0016, 0.032?±?0.0, 0.090?±?0.001, and 0.350?±?0.017?mM, respectively.     

An evaluation of the RNase H inhibitory effects of Vietnamese medicinal plant extracts and natural compounds

Context: Acquired immune deficiency syndrome (AIDS) is a severe pandemic disease especially prevalent in poor and developing countries. Thus, developing specific, potent antiviral drugs that restrain infection by human immunodeficiency virus type 1 (HIV-1), a major cause of AIDS, remains an urgent priority.

Objective: This study evaluated 32 extracts and 23 compounds from Vietnamese medicinal plants for their inhibitory effects against HIV-1 ribonuclease H (RNase H) and their role in reversing the cytopathic effects of HIV.

Materials and methods: The plants were air-dried and extracted in different solvent systems to produce plant extracts. Natural compounds were obtained as previously published. Samples were screened for RNase H inhibition followed by a cytopathic assay. Data were analyzed using the Microsoft Excel.

Results and discussion: At 50?μg/mL, 11 plant extracts and five compounds inhibited over 90% of RNase H enzymatic activity. Methanol extracts from Phyllanthus reticulatus and Aglaia aphanamixis leaves inhibited RNase H activity by 99 and 98%, respectively, whereas four extracts showed modest protection against the cytopathic effects of HIV.

Conclusion: The screening results demonstrated that the butanol (BuOH) extract of Celastrus orbiculata leaves, methanol (MeOH) extracts of Glycosmis stenocarpa stems, Eurya ciliata leaves, and especially P. reticulatus leaves showed potential RNase H inhibition and protection against the viral cytopathic effects of HIV-1. Further chemical investigations should be carried out to find the active components of these extracts and compounds as potential anti-HIV drug candidates.     

Applications for regulatory region of nitric oxide synthase isoforms

This patent application focuses on new regulatory sites found in the flavin mononucleotide (FMN) binding domain of endothelial nitric oxide synthase (eNOS) and neuronal nitric oxide synthase (nNOS), the two constitutive nitric oxide synthases (cNOS). The new regulatory sites differ on the two enzymes. The inducible nitric oxide synthase (iNOS) lacks this extra polypeptide insert. It is alleged that this insert acts as an autoinhibitory control by limiting calcium-calmodulin (CaM) binding to the enzyme.     

Biomarkers in Occupational Volatile Organic Chemical Exposure

Evidence exists that in certain groups of workers exposed to volatile organic chemicals, there is subclinical renal damage and dysfunction. Also, there is activation of biological mechanisms that are suggested links between volatile organic chemical exposure and renal disease. Notably, the workers studied are employed in factories where exposures are considered controlled, with on-site professional health and safety management. Recent studies continue to indicate an increased risk of renal disease in those exposed to volatile organic chemicals.     

Characterization of indoor air contaminants in a randomly selected set of commercial nail salons in Salt Lake County,Utah, USA

Air samples were collected in 12 randomly selected commercial nail salons in Salt Lake County, Utah. Measurements of salon physical/chemical parameters (room volume, CO₂ levels) were obtained. Volatile organic compound (VOC) concentrations were collected using summa air canisters and sorbent media tubes for an 8-h period. Multivariate analyses were used to identify relationships between salon physical/chemical characteristics and the VOCs found in the air samples. The ACGIH^® additive mixing formula was also applied to determine if there were potential overexposures to the combined airborne concentrations of chemicals monitored. Methyl methacrylate was detected in 58% of the establishments despite having been banned for use in nail products by the state of Utah. Formaldehyde was found above the NIOSH REL^® (0.016?ppm) in 58% of the establishments. Given the assortment of VOCs to which nail salon workers are potentially exposed, a combination of engineering as well as personal protective equipment is recommended.     

A Ca2+ chelator ameliorates chromium (VI)-induced hepatocyte L-02 injury via down-regulation of voltage-Dependent anion channel 1 (VDAC1) expression

Hexavalent chromium could result in cell malfunctions. Intracellular Ca²⁺ ([Ca²⁺]_i) content and VDAC1 expression are both important features related to cell survial. This study aimed to explore the mechanism of cell injury induced by Cr(VI) and tentatively offer clues to repairing this cell damage using [Ca²⁺]_i and VDAC1. L-02 hepatocytes were treated with Cr(VI)/BAPTA, and the levels of [Ca²⁺]_i and cell injury associated with Cr(VI) were determined in addition to the effect of BAPTA. The expression of VDAC1 in Cr(VI)-induced cells was evaluated. The results showed a dose-dependent elevation of the level of VDAC1 and the mRNA level of the VDAC1 biogenesis-related gene Sam50. BAPTA could ameliorate less severe damage induced by 4 μM Cr(VI) via reducing VDAC1 and Sam50. Additionally, cell injury caused by less than 4 μM Cr(VI) could be ameliorated by VDAC1 knockdown. Taken together, the findings of this study suggest that inhibition of intracellular Ca^2± overload could protect cells from damage and that VDAC1 plays a considerable role in Cr(VI)-induced liver injury.