Oxidative stress-induced apoptosis is associated with alterations in mitochondrial caspase activity and Bcl-2-dependent alterations in mitochondrial pH (pHm)

Oxidative stress, the result of cellular production of reactive oxygen species (ROS), has been implicated in a number of diseases of the eye. Exposure of eye tissues (e.g. the cornea and retina) to oxidative stress over time has been hypothesized to underlie the development of age-related macular degeneration (AMD) and maturity onset cataract formation. Light-induced free radicals can damage the eye, and alterations in the antioxidant defenses of the eye have been suggested to play a role in the etiology of glaucoma. Mitochondria are both a major endogenous source and target of ROS, and oxidative stress has been shown to induce apoptotic cell death by targeting the mitochondria directly. Mitochondrial-dependent apoptosis has been shown to require release of cytochrome c from mitochondria and subsequent activation of a specific class of cytoplasmic proteases known as caspases. Bcl-2, an anti-apoptotic protein localized to mitochondria, has been shown to inhibit cytochrome c release and protect against oxidative stress-induced apoptosis. Here we demonstrate that oxidative stress causes activation of mitochondrial matrix caspase-2 and -9 activity that is associated with Bcl-2-inhibitable acidification of mitochondrial pH (pH(m)). In conjunction with recent reports that caspase activation is maximal at acidic pH, these findings have led us to hypothesize that Bcl-2 may modulate cytochrome c release following oxidative stress by modifying the pH-dependent activation of mitochondrial caspase activity. These studies provide an increased understanding of the mechanism(s) by which oxidative stress damages tissues, and may have important therapeutic implications for treatment of opthamological diseases.     

Using human extra-cortical local field potentials to control a switch

Individuals with profound paralysis and mutism require a communication channel. Traditional assistive technology devices eventually fail, especially in the case of amyotrophic lateral sclerosis (ALS) subjects who gradually become totally locked-in. A direct brain-to-computer interface that provides switch functions can provide a direct communication channel to the external world. Electroencephalographic (EEG) signals recorded from scalp electrodes are significantly degraded due to skull and scalp attenuation and ambient noise. The present system using conductive skull screws allows more reliable access to cortical local field potentials (LFPs) without entering the brain itself. We describe an almost locked-in human subject with ALS who activated a switch using online time domain detection techniques. Frequency domain analysis of his LFP activity demonstrates this to be an alternative method of detecting switch activation intentions. With this brain communicator system it is reasonable to expect that locked-in, but cognitively intact, humans will always be able to communicate.     

Dorsolateral prefrontal cortical pathology in generalized anxiety disorder: a proton magnetic resonance spectroscopic imaging study

OBJECTIVE: Few neuroimaging studies of generalized anxiety disorder have been conducted. The present study used proton magnetic resonance spectroscopy to assess concentrations of N-acetylaspartate, often considered a marker of neuronal viability, in generalized anxiety disorder patients. METHOD: N-Acetylaspartate/creatine resonance ratios were measured in the left and right dorsolateral prefrontal cortex and hippocampus of 15 medication-free generalized anxiety disorder patients and 15 age- and sex-matched healthy volunteers. RESULTS: Generalized anxiety disorder patients had a 16.5% higher N-acetylaspartate/creatine ratio in the right dorsolateral prefrontal cortex compared with healthy participants; 13 of 15 matched patient-comparison subject pairs displayed a difference in this direction. In addition, generalized anxiety disorder patients reporting childhood abuse had lower N-acetylaspartate/creatine ratios in the right dorsolateral prefrontal cortex than did nonabused patients. Metabolite differences were not detected in other regions. CONCLUSIONS: Generalized anxiety disorder is associated with asymmetric increases in the N-acetylaspartate/creatine ratio, a suggested marker of neuronal viability, in the prefrontal cortex. The findings also support prior research linking childhood abuse to reduced neuronal viability.     

Distinct expression of phosphorylated N-methyl-D-aspartate receptor NR1 subunits by projection neurons and interneurons in the striatum of normal and amphetamine-treated rats

N-methyl-D-aspartate (NMDA) receptors are heteromeric assemblies of subunits (NR1 and NR2A-D), and are enriched in the striatum. Receptor phosphorylation has recently been demonstrated on the NR1 subunit at three serine residues, 897, 896, and 890, which appear to correspond to the level of receptor activity. In this study, expression of phospho-specific NR1 subunits at serine 897 (pNR1S897), serine 896 (pNR1S896), or serine 890 (pNR1S890) in neurochemically identified neurons of the adult rat striatum was detected by using double-immunofluorescent labeling or combined in situ hybridization and immunohistochemistry. In both the dorsal and ventral striatum, pNR1S897 was expressed at high levels in projection neurons containing >55% dynorphin (striatonigral) and >90% enkephalin (striatopallidal) and in interneurons that were 100% positive for choline, >90% positive for parvalbumin, and >45% positive for somatostatin (co-containing neuropeptide Y and neuronal nitric oxide synthase). Low levels of pNR1S896 were present in a small portion of projection neurons (<15% for both populations of projection neurons) and were almost lacking in the three types of interneurons. Interestingly, pNR1S890 was exclusively expressed in most parvalbumin-containing interneurons (70-80%). Acute administration of a psychostimulant, amphetamine, increased the number of dynorphin-containing projection neurons and parvalbumin interneurons showing detectable levels of pNR1S896 and pNR1S890, respectively. These results demonstrate the distinct expression of phospho-NR1 subunits in different populations of striatal projection neurons and interneurons at variable levels in normal rats; they also demonstrate that phosphorylation of NR1, at least on serine 896 and 890 sites, is sensitive to drug exposure.     

Four new stilbenoids from the lianas of Gnetum montanum f. megalocarpum

From the lianas of Gnetum montanum Markgr. f. megalocarpum Markgr., four new stilbenoids, gnetumontanins A - D ( 1 - 4) were obtained together with 16 known compounds. Gnetumontanin A ( 1) is the first oligostilbene dimerized from two oxyresveratrol units, gnetumontanin B ( 2) is a new stilbene trimer oligomerized from two oxyresveratrol and one resveratrol units, gnetumontanin C ( 3) is a new stilbenoid with a novel skeleton having a delta-lactone moiety and gnetumontanin D ( 4) is a glucoside of 3. Their structures were determined by means of spectroscopic evidence, especially 2D NMR techniques. Gnetumontanin B showed potent inhibition of TNF-alpha with an inhibitory ratio of 58.1 % (P < 0.05) at a concentration of 10 ( - 5) mol L (-1) and the IC (50) was 1.49 x 10 ( - 6) mol L (-1).     

中性粒细胞粘附分子CD11b表达对新生儿败血症早期诊断价值的研究

目的　观察新生儿败血症中性粒细胞粘附分子CD11b表达的规律 ,并评价其在新生儿败血症早期诊断中的价值。方法　将 5 1例临床疑似败血症的新生儿根据其临床表现及WBC、PLT、血浆CRP和未成熟中性粒细胞数与中性粒细胞总数比值 (I/T)四项指标 ,分为败血症和可疑败血症两组。采用全血流式细胞术检测患儿和 15例正常对照组新生儿中性粒细胞CD11b的平均荧光强度 (MFI)。结果　败血症组 2 3例 ,可疑败血症组 2 8例。两组中性粒细胞CD11b分别为 (32 0± 189)、(4 5 6± 2 13)MFI,均显著低于正常对照组的 (10 90± 338)MFI(t分别为 - 9 0 1、- 7 5 6 ,P均 <0 0 0 1) ,败血症组又低于可疑败血症组 ,差异有显著性 (t=- 2 39,P <0 0 5 )。高CRP组患儿CD11b为 (2 11± 16 4 )MFI,低于低CRP组的 (5 0 5± 2 6 5 )MFI,差异有显著性 (t=2 6 4 ,P <0 0 5 )。中性粒细胞CD11b≤ 6 0 0MFI对疑似败血症新生儿诊断的敏感性、特异性、阳性和阴性预测值分别为 86 3%、10 0 %、10 0 %、6 8 2 % ,CD11b检测阳性率为 86 3% ,高于血培养的阳性率 (17 6 % ) ,差异有显著性 (χ2 m=31 2 ,P <0 0 5 )。结论　新生儿败血症中性粒细胞粘附分子CD11b表达下调 ,其下调与感染严重程度有一定关系。中性粒细胞CD11b的动态检测对早期     

Genetic alterations in primary cutaneous CD30+ anaplastic large cell lymphoma

Primary cutaneous CD30+ anaplastic large cell lymphoma (C-ALCL) represents a distinct clinical subtype of CD30+ anaplastic large cell lymphomas. The etiology and underlying molecular pathogenesis of C-ALCL remain unclear. This study aimed to investigate genetic changes in C-ALCL. Comparative genomic hybridization (CGH) analysis of 23 DNA samples from 15 C-ALCL cases identified chromosome imbalances (CI) in 10 samples from eight cases (43%). The mean number of CI per sample was 2.09 +/- 3.86, with gains (2.00 +/- 3.85) more common than losses (0.09 +/- 0.29). The most frequent CI were gains of 1/1p and 5 (50%) and 6, 7, 8/8p, and 19 (38%). Microarray-based CGH analysis of six DNA samples from five cases with CI revealed genomic imbalances (GI) in all of the cases studied. This included oncogene copy number gains of FGFR1 (8p11) in three cases, and NRAS (1p13.2), MYCN (2p24.1), RAF1 (3p25), CTSB (8p22), FES (15q26.1), and CBFA2 (21q22.3) in two cases. Real-time PCR analysis of nine DNA samples from eight cases with CI and GI detected amplifications of CTSB and RAF1 in seven cases (88%), REL (2p13p12) and JUNB (19p13.2) in six cases (75%), and MYCN and YES1 (18p11.3) in four cases (50%). Immunohistochemical staining of paraffin sections from six cases demonstrated expression of JUNB protein in five cases and BCL2 in three cases. These results reveal a consistent pattern of genetic alterations in C-ALCL and provide the molecular basis for further investigation of this disease.     

Microcapsules with improved mechanical stability for hepatocyte culture

Packed-bed or fluidized-bed bioreactor filled with microencapsulated hepatocytes has been proposed as one of the promising designs for bioartificial liver assist device (BLAD) because of potential advantages of high mass transport rate and optimal microenvironment for hepatocyte culture. Recently, we have developed a microcapsule system for the encapsulation of hepatocytes. The microcapsules consist of an inner core of modified collagen and an outer shell of terpolymer of methyl methacrylate, methacrylate and hydroxyethyl methacrylate. Cells encapsulated in these microcapsules exhibit enhanced cellular functions. Improving the mechanical stability of the microcapsules to withstand the shear stress induced by high perfusion rate would be crucial to the success of BLAD applications. In this study, we investigated the effects of terpolymer molecular weight (M(w)) on the mechanical property of these microcapsules and the differentiated functions of encapsulated hepatocytes. Six terpolymers with different M(w) were synthesized using radical polymerization in solution by adjusting the reaction temperature and the initiator concentration. All the terpolymers formed microcapsules with the methylated collagen. While the terpolymer M(w) had little effect on the capsule membrane thickness and permeability of serum albumin, the mechanical property of the microcapsules was significantly improved by the higher M(w) of the terpolymer. Differentiated functions of the hepatocytes cultured in the microcapsules, including urea synthesis, albumin synthesis and cytochrome P450 metabolic activity, were not significantly affected by the terpolymer M(w).