Contribution of different somatosensory afferent input to subcortical somatosensory evoked potentials in humans

ObjectivesTo investigate the subcortical somatosensory evoked potentials (SEPs) to electrical stimulation of either muscle or cutaneous afferents.MethodsSEPs were recorded in 6 patients suffering from Parkinson’s disease (PD) who underwent electrode implantation in the pedunculopontine (PPTg) nucleus area. We compared SEPs recorded from the scalp and from the intracranial electrode contacts to electrical stimuli applied to: 1) median nerve at the wrist, 2) abductor pollicis brevis motor point, and 3) distal phalanx of the thumb. Also the high-frequency oscillations (HFOs) were analysed.ResultsAfter median nerve and pure cutaneous (distant phalanx of the thumb) stimulation, a P1-N1 complex was recorded by the intracranial lead, while the scalp electrodes recorded the short-latency far-field responses (P14 and N18). On the contrary, motor point stimulation did not evoke any low-frequency component in the PPTg traces, nor the N18 potential on the scalp. HFOs were recorded to stimulation of all modalities by the PPTg electrode contacts.ConclusionsStimulus processing within the cuneate nucleus depends on modality, since only the cutaneous input activates the complex intranuclear network possibly generating the scalp N18 potential.SignificanceOur results shed light on the subcortical processing of the somatosensory input of different modalities.     

Out of the boxes,out of the silos: The need of interdisciplinary collaboration to reduce poor-quality medical products in the supply chain

In this paper, we argue that understanding and addressing the problem of poor-quality medical products requires a more interdisciplinary approach than has been evident to date. While prospective studies based on rigorous standardized methodologies are the gold standard for measuring the prevalence of poor-quality medical products and understanding their distribution nationally and internationally, they should be complemented by social science research to unpack the complex set of social, economic, and governance factors that underlie these patterns. In the following sections, we discuss specific examples of prospective quality surveys and of social science studies, highlighting the value of cross-sector partnerships in driving high-quality, policy-relevant research in this area.     

Immunogenicity of next-generation HPV vaccines in non-human primates: Measles-vectored HPV vaccine versus Pichia pastoris recombinant protein vaccine

Human papillomavirus (HPV) infection is the most common sexually transmitted disease worldwide. HPVs are oncogenic small double-stranded DNA viruses that are the primary causal agent of cervical cancer and other types of cancers, including in the anus, oropharynx, vagina, vulva, and penis. Prophylactic vaccination against HPV is an attractive strategy for preventing cervical cancer and some other types of cancers. However, there are few safe and effective vaccines against HPV infections. Current first-generation commercial HPV vaccines are expensive to produce and deliver.The goal of this study was to develop an alternate potent HPV recombinant L1-based vaccines by producing HPV virus-like particles into a vaccine that is currently used worldwide. Live attenuated measles virus (MV) vaccines have a well-established safety and efficacy record, and recombinant MV (rMV) produced by reverse genetics may be useful for generating candidate HPV vaccines to meet the needs of the developing world.We studied in non-human primate rMV-vectored HPV vaccine in parallel with a classical alum adjuvant recombinant HPV16L1 and 18L1 protein vaccine produced in Pichia pastoris. A combined prime-boost approach using both vaccines was evaluated, as well as immune interference due to pre-existing immunity against the MV.The humoral immune response induced by the MV, Pichia-expressed vaccine, and their combination as priming and boosting approaches was found to elicit HPV16L1 and 18L1 specific total IgG and neutralizing antibody titres. Pre-existing antibodies against measles did not prevent the immune response against HPV16L1 and 18L1.     

肝细胞癌TACE术后病灶存活或复发18F-FDGPET/CT和增强CT诊断价值Meta分析

目的采用Meta分析方法评价¹⁸F-脱氧葡萄糖正电子发射计算机体层摄影(¹⁸F-FDG PET/CT)和增强CT(CECT)诊断经导管肝动脉化疗栓塞术(TACE)术后存活或复发病灶的临床价值。方法根据PRISMA报告规范开展Meta分析。检索PubMed、Embase、Cochrane Library、Web of Science、中国知网、万方和维普数据库中¹⁸F-FDG PET/CT和CECT诊断TACE术后存活或复发病灶的临床研究,时间至2019-04。由2位研究人员独立筛选文献、提取资料,根据诊断准确性研究质量评价工具-2(QUADAS-2)评价纳入研究的偏倚风险后,采用Stata 12.0软件进行Meta分析,计算其汇总敏感度(Sen)和特异度(Spe),绘制受试者工作特征曲线(SROC)并计算曲线下面积(AUC)。结果共纳入10篇¹⁸F-FDG PET/CT及13篇CECT诊断TACE术后存活或复发病灶的原始研究,分别包括322例患者的467个病灶和748例患者的943个病灶。Meta分析显示,¹⁸F-FDG PET/CT诊断TACE术后存活或复发病灶的Sen=0.92(95%CI为0.87~0.94)、Spe=0.95(95%CI为0.82~0.99)、AUC=0.97(95%CI为0.93~0.99);CECT诊断TACE术后存活或复发病灶的Sen=0.72(95%CI为0.66~0.78)、Spe=0.99(95%CI为0.93~1.00)、AUC=0.87(95%CI为0.83~0.89)。此外,CECT诊断TACE术后存活或复发Sen(Z=2.34,P=0.02)和AUC(Z=2.21,P=0.03)值低于¹⁸F-FDG PET/CT,差异有统计学意义。结论相比于CECT,¹⁸F-FDG PET/CT对TACE术后存活或复发病灶具有较高诊断效能,可视为TACE术后存活或复发病灶有效的影像学诊断方法。     

Dietary n-3 long chain PUFA supplementation promotes a pro-resolving oxylipin profile in the brain

The brain is highly enriched in long chain polyunsaturated fatty acids (LC-PUFAs) that display immunomodulatory properties in the brain. At the periphery, the modulation of inflammation by LC-PUFAs occurs through lipid mediators called oxylipins which have anti-inflammatory and pro-resolving activities when derived from n-3 LC-PUFAs and pro-inflammatory activities when derived from n-6 LC-PUFAs. However, whether a diet rich in LC-PUFAs modulates oxylipins and neuroinflammation in the brain has been poorly investigated. In this study, the effect of a dietary n-3 LC-PUFA supplementation on oxylipin profile and neuroinflammation in the brain was analyzed. Mice were given diets deficient or supplemented in n-3 LC-PUFAs for a 2-month period starting at post-natal day 21, followed by a peripheral administration of lipopolysaccharide (LPS) at adulthood. We first showed that dietary n-3 LC-PUFA supplementation induced n-3 LC-PUFA enrichment in the hippocampus and subsequently an increase in n-3 PUFA-derived oxylipins and a decrease in n-6 PUFA-derived oxylipins. In response to LPS, n-3 LC-PUFA deficient mice presented a pro-inflammatory oxylipin profile whereas n-3 LC-PUFA supplemented mice displayed an anti-inflammatory oxylipin profile in the hippocampus. Accordingly, the expression of cyclooxygenase-2 and 5-lipoxygenase, the enzymes implicated in pro- and anti-inflammatory oxylipin synthesis, was induced by LPS in both diets. In addition, LPS-induced pro-inflammatory cytokine increase was reduced by dietary n-3 LC-PUFA supplementation. These results indicate that brain n-3 LC-PUFAs increase by dietary means and promote the synthesis of anti-inflammatory derived bioactive oxylipins. As neuroinflammation plays a key role in all brain injuries and many neurodegenerative disorders, the present data suggest that dietary habits may be an important regulator of brain cytokine production in these contexts.     

miR-21对视网膜母细胞瘤细胞增殖的影响及作用机制

目的　探讨MicroRNA-21（miR-21）对视网膜母细胞瘤(RB)细胞增殖的影响及作用机制。方法　采用Real-time PCR技术检测miR-21在正常视网膜组织和确诊RB组织中的表达情况；然后在转染的基础上运用MTT检查RB细胞存活率、流式细胞仪检测细胞凋亡率。Western blot法检测与细胞凋亡相关蛋白PDCD4、Bax、Bcl-2的表达。结果　与正常视网膜组织miR-21表达 （0.703±0.071）相比，RB组织miR-21为高表达（2.214±0.162），差异有统计学意义（P<0.01）。在Weri-Rb-1细胞中，与NC组(2.245±0.213)相比，miR-21抑制剂转染后明显降低了miR-21的表达水平，miR-21 inhibitor组为0.683±0.075,差异有统计学意义 （P<0.01）。两组细胞转染后24 h、48 h、72 h、96 h，MTT测定法检测细胞活力结果显示:两组24 h的A值比较，差异无统计学意义 （P>0.05），miR-21 inhibitor 组在 48 h、72 h、 96 h的A值均低于 NC 组，差异均有统计学意义 （均为P<0.01）。流式细胞术检测结果显示:NC组凋亡细胞在总细胞中百分比为（3.045±0.301）%和（4.832±0.493）%，miR-21 inhibitor组凋亡细胞在总细胞中百分比为（2.593±0.257）%和（40.167±4.014）%，miR-21 inhibitor组Weri-Rb-1细胞的凋亡率明显高于miR-21 NC组(P<0.01)。Western blot检测结果显示:NC组PDCD4表达（0.192±0.045）相比miR-21 inhibitor组（0.683±0.091）表达明显减少，NC组Bax的蛋白表达水平（0.143±0.036）相比miR-21 inhibitor组（1.192±0.054）也明显减少，差异均有统计学意义（P<0.01)，NC组Bcl-2蛋白表达（0.864±0.038）相比miR-21 inhibitor组（0.257±0.026）明显增多，差异有统计学意义（P<0.05)。结论　miR-21是RB的促癌基因，miR-21抑制剂可以通过降低miR-21表达抑制肿瘤细胞的增殖、促进细胞凋亡，这一过程与PDCD4、Bax、Bcl-2等凋亡相关蛋白有关。     

膀胱癌的~(18)F-FDG PETCT显像诊断价值研究

目的研究~(18)F-FDG PETCT显像对膀胱癌的诊断价值。方法选取我院核医学科2013年3月-2015年2月收治的34例可疑膀胱癌患者,术前分别采用增强CT和~(18)F-FDG PETCT显像进行诊断,通过参考手术病理结果回顾性分析~(18)F-FDG PETCT显像诊断的效果。结果该34例经手术病理观察均确诊为移行细胞癌,增强CT、~(18)F-FDG PETCT显像诊断准确度分别为91.18%、94.12%,差异无统计学意义(P0.05);术中共有11例膀胱肿瘤出现盆腔淋巴结或邻近组织转移、浸润,~(18)F-FDG PETCT显像诊断准确度为72.73%,明显高于增强CT(27.27%),具有统计学意义(P0.05)。结论 ~(18)F-FDG PETCT显像和增强CT均是临床诊断膀胱癌的有效方法,但~(18)F-FDG PETCT显像在观察膀胱肿瘤病灶的转移和对邻近组织的浸润效果较好,对指导临床诊断和了解肿瘤病变具有重要参考价值。     

Carboxylesterase catalyzed 18O-labeling of carboxylic acid and its potential application in LC-MS/MS based quantification of drug metabolites

LC-MS quantification of drug metabolites is sometimes impeded by the availability of internal standards that often requires customized synthesis and/or extensive purification. Although isotopically labeled internal standards are considered ideal for LC-MS/MS based quantification, de novo synthesis using costly isotope-enriched starting materials makes it impractical for early stage of drug discovery. Therefore, quick access to these isotope-enriched compounds without chemical derivatization and purification will greatly facilitate LC-MS/MS based quantification. Herein, we report a novel ¹⁸O-labeling technique using metabolizing enzyme carboxylesterase (CES) and its potential application in metabolites quantification study. Substrates of CES typically undergo a two-step oxygen exchange with H₂¹⁸O in the presence of the enzyme, generating singly- and doubly-¹⁸O-labeled carboxylic acids; however, unexpected hydrolytic behavior was observed for three of the test compounds – indomethacin, piperacillin and clopidogrel. These unusual observations led to the discovery of several novel hydrolytic mechanisms. Finally, when used as internal standard for LC-MS/MS based quantification, these in situ labeled compounds generated accurate quantitation comparable to the conventional standard curve method. The preliminary results suggest that this method has potential to eliminate laborious chemical synthesis of isotope-labeled internal standards for carboxylic acid-containing compounds, and can be developed to facilitate quantitative analysis in early-stage drug discovery.