Effects of the anion transport inhibitor,SITS, on the proximal straight tubule of the rabbit perfusedin vitro

Summary Conventional microelectrodes were used to study the effects of SITS (4-acetamido-4-isothiocyanostilbene-2,2-disulfonate) on the basolateral membrane potentialVbl of the superficial proximal straight tubule (PST) of the rabbit kidney perfusedin vitro. Addition of 0.1mm SITS to the bathing solution resulted in a slow and irreversible hyperpolarization ofVbl from –42.5±1.17 (37) mV to –77.3±0.83 (52) mV. The new steady-state potential was reached in 10 to 15 min and was accompanied by visible cell swelling. Associated with thisVbl hyperpolarization was: 1) an increased steady-state depolarization (from 6.2±0.77 (17) mV to 25.7±0.83 (29) mV) in response to increasing bath potassium concentration from 5 to 16.7mm (HK); 2) a decreased transient depolarization (from 19.8±1.88 (8) mV to 0.43±0.37 (8) mV) in response to decreasing bath bicarbonate concentration from 22 to 6.6mm at constant bath pH (L-HCO₃); and 3) inhibition of a depolarizing overshoot and a decreased steady-state depolarization (from 35.9±1.84 (12) mV to 4.7±1.37 (13) mV) in response to reducing bath sodium concentration from 144 to zero (0-Na). Sodium, chloride and NMDG (N-methyl-d-glucamine) were used as the substituting ions, respectively. These results are consistent with the presence of a coupled sodium-bicarbonate carrier in the basolateral membrane which is electrogenic and SITS inhibitable. Comparison of the time course of SITS effects on these ion-substitution responses suggests that the inhibition of the bicarbonate exit pathway(s) is the primary event and that the changes inVbl and in the steady-stateVbl responses to HK and 0-Na are secondary events which may be related to changes in intracellular composition and/or basolateral membrane properties.     

Building Electron/Proton Nanohighways for Full Utilization of Water Splitting Catalysts

Low electron/proton conductivities of electrochemical catalysts, especially earth‐abundant nonprecious metal catalysts, severely limit their ability to satisfy the triple‐phase boundary (TPB) theory, resulting in extremely low catalyst utilization and insufficient efficiency in energy devices. Here, an innovative electrode design strategy is proposed to build electron/proton transport nanohighways to ensure that the whole electrode meets the TPB, therefore significantly promoting enhance oxygen evolution reactions and catalyst utilizations. It is discovered that easily accessible/tunable mesoporous Au nanolayers (AuNLs) not only increase the electrode conductivity by more than 4000 times but also enable the proton transport through straight mesopores within the Debye length. The catalyst layer design with AuNLs and ultralow catalyst loading (≈0.1 mg cm^?2) augments reaction sites from 1D to 2D, resulting in an 18‐fold improvement in mass activities. Furthermore, using microscale visualization and unique coplanar‐electrode electrolyzers, the relationship between the conductivity and the reaction site is revealed, allowing for the discovery of the conductivity‐determining and Debye‐length‐determining regions for water splitting. These findings and strategies provide a novel electrode design (catalyst layer + functional sublayer + ion exchange membrane) with a sufficient electron/proton transport path for high‐efficiency electrochemical energy conversion devices.     

Oxylipin formation in Nostoc punctiforme (PCC73102)

The dioxygenation of polyunsaturated fatty acids is mainly catalyzed by members of the lipoxygenase enzyme family in flowering plants and mosses. Lipoxygenase products can be metabolized further and are known as signalling substances that play a role in plant development as well as in plant responses to wounding and pathogen attack. Apart from accumulating data in mammals, flowering and non-flowering plants, information on the relevance of lipid peroxide metabolism in prokaryotic organisms is scarce. Thus we aimed to isolate and analyze lipoxygenases and oxylipin patterns from cyanobacterial origin. DNA isolated from Nostoc punctiforme strain PCC73102 yielded sequences for at least two different lipoxygenases. These have been cloned as cDNAs and named NpLOX1 and NpLOX2. Both proteins were identified as linoleate 13-lipoxygenases by expression in E. coli. NpLOX1 was characterized in more detail: It showed a broad pH optimum ranging from pH 4.5 to pH 8.5 with a maximum at pH 8.0 and alpha-linolenic acid was the preferred substrate. Bacterial extracts contain more 13-lipoxygenase-derived hydroperoxides in wounded than in non-wounded cells with a 30-fold excess of non-esterified over esterified oxylipins. 9-Lipoxygenase-derived derivatives were not detectable. 13-Lipoxygenase-derived hydroperoxides in esterified lipids were present at almost equal amounts compared to non-esterified hydroperoxides in non-wounded cells. These results suggest that 13-lipoxygenases acting on free fatty acids dominate in N. punctiforme strain PCC73102 upon wounding.     

Lipoxygenases during Brassica napus seed germination

The peroxidation of polyunsaturated fatty acids is mostly catalyzed by members of the lipoxygenase enzyme family. Lipoxygenase products can be metabolized further in the oxylipin pathway and are known as signalling substances that play a role in plant development as well as in plant responses to wounding and pathogen attack. Apart from accumulating data in model plants like Arabidopsis, information on the relevance of lipid peroxide metabolism in the crop plant oilseed rape is scarce. Thus we aimed to analyze lipoxygenases and oxylipin patterns in seedlings of oilseed rape. RNA isolated from 3 day etiolated seedlings contains mRNAs for at least two different lipoxygenases. These have been cloned as cDNAs and named Bn-Lox-1fl and Bn-Lox-2fl. The protein encoded by Bn-Lox-2fl was identified as a 13-lipoxygenase by expression in Escherichia coli. The Bn-Lox-1fl yielded an inactive protein when expressed in E. coli. Based on Bn-Lox-1fl active site determinants and on sequence homology the Bn-Lox-1fl is most likely a 9-lipoxygenase. Both genes are expressed in light-grown and etiolated cotyledons as well as in leaves. Bn-Lox-2fl protein is more abundant in cotyledons of etiolated seedlings than in cotyledons of green seedlings. Both 13- and 9-lipoxygenase-derived hydroperoxides can be detected during germination. Etiolated seedlings contain more lipoxygenase-derived hydroperoxides in non esterified fatty acids than green seedlings. The 13-lipoxygenase derivatives are 6-8-fold more abundant than the 9-derivatives. Lipoxygenase-derived hydroperoxides in esterified lipids are almost not present during germination. These results suggest that 13-lipoxygenases acting on free fatty acids dominate during B. napus seed germination.     

Developmental control of inositol phosphate biosynthesis is altered in the brain of both curly and phenotypically normal straight tail mutant mice

BACKGROUND : Altered levels of inositol phosphate in the central nervous system (CNS) are hypothesized to produce distorted brain signaling and lead to numerous neurologic maladies. Little is known of mechanisms controlling the complex metabolic flux of inositol phosphate. Less is known of controls that regulate inositol‐phosphate biosynthesis in the mammalian brain. The expression of 1L‐myo‐inositol?1 phosphate synthase (MIP), the only enzyme known to synthesize inositol phosphate, was studied in the brain of normal (CBA) and curly tail (CT) mutant mice. The CT strain exhibits a neural tube defect, spina bifida, responsive to inositol supplementation, but not to folic acid treatment. METHODS : Utilizing enzyme assays to determine the specific activity of MIP, Western blotting to detect expression, gas chromatography/mass spectrometry to measure inositol concentration, and statistical analyses to evaluate quantitative data, MIP expression was analyzed in newborn, young, and adult brains of CBA and CT (curly tail [ct‐CT] and straight tail [st‐CT]) mutant mice. RESULTS : Data analyses suggest there is a significant difference in MIP activity in the brain of CBA mice as compared to that of CT mutant mice and that temporal and spatial control of MIP expression and inositol concentrations are altered in the brain of both the ct‐CT and phenotypically normal st‐CT mutant. Moreover, two differentially expressed forms of MIP were identified in the adult mouse brain. CONCLUSIONS : These findings implicate a role for MIP in the maturation of the CNS and evoke a hypothesis regarding the regulation of inositol phosphate biosynthesis in brain development. Birth Defects Research (Part A), 2009. © 2009 Wiley‐Liss, Inc.     

中医正骨手法改善桡骨远端伸直型骨折患者腕关节功能的临床研究及疗效的影响因素分析

摘要 目的：观察中医正骨手法在桡骨远端伸直型骨折中的临床应用价值,并分析疗效的影响因素。方法：选择四川省骨科医院2020年1月~2022年1月期间收治的桡骨远端伸直型骨折患者152例,按照治疗方式的不同将患者分为对照组（给予石膏固定）和研究组（应用中医正骨手法治疗）,例数分别为77例和75例。对比两组优良率、临床指标、腕关节活动度和X线相关影像学指标。同时采用多因素Logistic回归分析影响研究组腕关节功能疗效的相关因素。结果：治疗后,研究组的优良率明显高于对照组（P<0.05）。研究组手背消肿时间、疼痛缓解时间、骨折愈合时间均短于对照组（P<0.05）。两组治疗后12周掌屈、背伸、桡偏、尺偏、旋前、旋后活动度均扩大,且研究组均大于对照组（P<0.05）。两组治疗后12周掌倾角、尺偏角、桡骨高度均增加,且研究组均大于对照组（P<0.05）。单因素分析显示,研究组腕关节功能优良率与年龄、性别、骨质疏松、功能锻炼、掌倾角、尺偏角、桡骨高度、骨折端稳定性、受伤能量、利手情况有关（P<0.05）,而与体质量指数、就诊时间、基础疾病、骨折类型、固定时间无关（P>0.05）。多因素Logistic回归分析显示：性别为女、骨质疏松、无功能锻炼、掌倾角偏小、桡骨高度偏短、骨折端不稳定、受伤能量为高能量、利手是影响腕关节功能优良率的危险因素（P<0.05）。结论：中医正骨手法可有效改善桡骨远端伸直型骨折患者腕关节功能,减少骨折愈合及疼痛缓解时间。此外,患者腕关节功能的优良率还受到性别、骨质疏松、功能锻炼、掌倾角、桡骨高度、骨折端稳定性、受伤能量、利手情况的影响,值得引起临床重视。     

Structural aspects of pathology in Alzheimer's disease

The characteristic lesions of Alzheimer's disease, neurofibrillary tangles and neuritic plaques, are the sites of accumulation of abnormal fibrillar material. The structure of the paired helical filament from tangles has been analysed by electron microscopy and biochemical studies have shown that it contains microtubule associated protein tau as a component. Fibrils of β-amyloid in the neuritic plaque arise by polymerization of a small proteolytic fragment of a much larger precursor protein. It is not yet clear what triggers the events that lead to assembly of the abnormal structures nor why the structures once formed are so resistant to turnover.