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The membrane phospholipid composition in mammalian brain can be modified either by nutrients such as dietary fatty acids, or by certain toxic substances such as methylmercury (MeHg), leading to various biological and toxic effects. The present study evaluated the effects of eicosapentaenoic acid (EPA) and MeHg on the composition of the two most abundant membrane phospholipid classes, i.e., phosphatidylcholines (PtdCho) and phosphatidylethanolamines (PtdEtn), in mouse brain by using a two-level factorial design. The intact membrane PtdCho and PtdEtn species were analyzed by liquid chromatography-mass spectrometry. The effects of EPA and MeHg on the PtdCho and PtdEtn composition were evaluated by principal component analysis and ANOVA. The results showed that EPA and MeHg had different effects on the composition of membrane PtdCho and PtdEtn species in brain, where EPA showed strongest impact. EPA led to large reductions in the levels of arachidonic acid (ARA)-containing PtdCho and PtdEtn species in brain, while MeHg tended to elevate the levels of ARA-containing PtdCho and PtdEtn species. EPA also significantly increased the levels of PtdCho and PtdEtn species with n-3 fatty acids. Our results indicate that EPA may to some degree counteract the alterations of the PtdCho and PtdEtn pattern induced by MeHg, and thus alleviate the MeHg neurotoxicity in mouse brain through the inhibition of ARA-derived pro-inflammatory factors. These results may assist in the understanding of the interaction between MeHg, EPA and phospholipids, as well as the risk and benefits of a fish diet.

The Paleogene and Neogene oil and gas in the western Qaidam basin have a regular distribution in three concentric zones from the edge to the center of the basin. Natural gas mainly occurs in the inner zone, and the gas-oil ratio of the northern area of the basin is significantly higher than that of the southern area. Large amounts of carbon isotope data of natural gas, plotted in X-shaped and comprehensive identification diagrams for the southern area and northern area, respectively, were used to identify the types of natural gas. The large-scale distribution of natural gas is highly consistent with the Ro values of major source rocks, but is poorly correlated with the type of organic matter. This indicates that the main controlling factor of natural gas distribution is organic matter maturity, and the kerogen types act as the basis for the formation of different types of natural gas. Paleouplifts and squeezed anticlines near hydrocarbon generation depression centers, which are major natural gas-rich regions, control the migration directions of natural gas, while hydrocarbon migration pathways and fault systems connecting gas sources are the most important factors for natural gas reservoir formation in the inner basin. Therefore, favorable zones for natural gas distribution can be predicted on the basis of the distribution of thermal evolution and the gas generation intensity of major source rocks as well as the structural map. The Shizigou-Youshashan-Yingdong-Dawusi, Youquanzi –Kaitemilike – Youdunzi, and Xiaoliangshan – Nanyishan – Dafengshan structural belts are favorable zones for natural gas accumulation. This study has important theoretical and practical significance for future natural gas exploration.

Ionic liquids (ILs) are attractive stationary phases to broaden selectivity in gas chromatography (GC). The rational design, selection and application of ILs in comprehensive two-dimensional GC is a desirable goal. In this study, methods to predict two-dimensional chromatograms of fatty acid methyl esters (FAMEs) starting from given structures of IL stationary phases and their interactions with FAME solutes are described. Molecular parameters of the dipole moment, lowest unoccupied molecular orbital energy and molar volume of different ILs were calculated by using Gaussian 09. With established correlations between molecular simulation and linear solvation energy relationships, molecular parameters were converted to s, e and l values for stationary phase descriptors. This allowed reliable prediction of the equivalent chain length of FAMEs on each IL column (with the correlation R2=0.98). Isovolatility curves in GC×GC space of reference saturated FAMEs were then determined for each IL column to take into account the dependence of retention time on temperature in temperature-programmed separation. The resulting predicted GC×GC chromatograms were compared with previously reported experimental results. Correlations with R2 values of 0.99 and 0.98 were achieved for the first- and second-dimension retention times, respectively.

Key Clinical Message High index of suspicion for adenovirus infection is required in renal graft dysfunction, especially in the setting of hematuria. Histology can mimic acute rejection, which creates a diagnostic dilemma. Tissue adenovirus immunostains, though usually reliable, may not be always positive like in our case.

Key Clinical Message Antiglomerular basement membrane (GBM) antibody disease is a vasculitis affecting glomerular capillaries, pulmonary capillaries, or both, with GBM deposition of autoantibodies. It can be both life‐ and organ‐threatening and delayed diagnosis may be detrimental. Alveolar hemorrhage and microscopic hematuria should be excluded in anybody who is suspected of this disease.

Key Clinical Message Cyst infection is a common complication of autosomal dominant polycystic kidney disease. It presents with vague clinical features and imaging findings which make the diagnosis challenging. Imaging findings can be misinterpreted as renal cell carcinoma, and biopsy of the lesion is often required for definitive diagnosis.

Key Clinical Message Membranoproliferative glomerulonephritis associated with mixed cryoglobulinemia is the most common form of kidney disease observed in relation to hepatitis C virus (HCV) infection. Rituximab, a monoclonal antibody against CD20, is an effective treatment for severe and/or refractory HCV‐related vasculitis and may evade the need for dialysis as in our patient.

Fatty acid methyl ester (FAME) profiling in complex fish oil and milk fat samples was studied using integrated comprehensive 2D GC (GC × GC) and multidimensional GC (MDGC). Using GC × GC, FAME compounds--cis- and trans-isomers, and essential fatty acid isomers--ranging from C18 to C22 in fish oil and C18 in milk fat were clearly displayed in contour plot format according to structural properties and patterns, further identified based on authentic standards. Incompletely resolved regions were subjected to MDGC, with Cn (n = 18, 20) zones transferred to a (2)D column. Elution behavior of C18 FAME on various (2)D column phases (ionic liquids IL111, IL100, IL76, and modified PEG) was evaluated. Individual isolated Cn zones demonstrated about four-fold increased peak capacities. The IL100 provided superior separation, good peak shape, and utilization of elution space. For milk fat-derived FAME, the (2)D chromatogram revealed at least three peaks corresponding to C18:1, more than six peaks for cis/trans-C18:2 isomers, and two peaks for C18:3. More than 17 peaks were obtained for the C20 region of fish oil-derived FAMEs using MDGC, compared with ten peaks using GC × GC. The MDGC strategy is useful for improved FAME isomer separation and confirmation.

GABAergic synaptic responses were studied by direct, monosynaptic activation of GABAergic interneurons in the CA1 region of in vitro hippocampal slices from rats made tolerant to the benzodiazepine, flurazepam. Monosynaptic IPSPs were elicited in CA1 pyramidal neurons, following 1 week oral flurazepam administration, by electrical stimulation at the stratum oriens/stratum pyramidale or stratum radiatum/ stratum-lacanosum border # 0.5 mm from the recording electrode plane. Excitatory input to pyramidal cells and interneurons was eliminated by prior superfusion of the glutamate receptor antagonists, APV (50 µM) and DNQX (10 µM). GABAA receptor- mediated early IPSPs were further isolated by perfusion of the GABAB antagonist, CGP 35348 (25 µM) or by diffusion of Cs 1 from the recording electrode. GABAB receptor- mediated late IPSPs were pharmacologically isolated by perfusion of the GABAA antagonist, picrotoxin (50 µM). There was a significant decrease in the amplitude of pharmacologically isolated early and late IPSPs in FZP-treated neurons without a change in passive membrane properties. A shift of the early IPSP, but not the late IPSP, reversal potential in FZP-treated neurons suggested that a change in the driving force for anions, presumably Cl 2 , in CA1 neurons was one important factor related to the decreased early IPSP amplitude after prolonged activation of GABAA receptors by flurazepam. A decreased early IPSP amplitude accompanied by a decreased late IPSP amplitude suggested that presynaptic GABA release onto FZP-treated pyramidal cells may also be reduced. We conclude from these data that an impairment of GABAergic transmission in CA1 pyramidal neurons associated with the development of tolerance during chronic benzodiazepine treatment may be related to the regulation of both pre- and postsynaptic mechanisms at the GABA synapse. Synapse 25:125-136, 1997. r 1997 Wiley-Liss, Inc.