促炎因子介导的体外培养人主动脉血管平滑肌细胞凋亡

目的 :探讨促炎因子对体外培养的人主动脉平滑肌细胞有无致凋亡作用。　　方法 :体外原代培养人主动脉平滑肌细胞 ,用免疫组化方法鉴定 ;肿瘤坏死因子 α (TNF α)和白细胞介素 1β (IL 1β)分别以浓度 2 0 μg/ml单独或二者共同与平滑肌细胞培养 3 6h ,实验分 4组 :TNF α组 (T组 )、IL 1β组 (I组 )、TNF α+IL 1β组 (TI组 )及对照组 ,采用流式细胞仪分析细胞凋亡及细胞周期。　　结果 :①细胞凋亡分析显示 :TI组两种因子的联合作用诱导人平滑肌细胞凋亡与对照组比明显增加 ,有显著性差异 (P <0 0 5 ) ,而二者单独作用未能诱导人平滑肌细胞凋亡。②细胞周期分析发现TI组在TNF α +IL 1β刺激下 ,细胞增殖能力与其他组比有明显下降 ,有显著性差异 (P <0 0 5 ) ,生长逐渐停滞 ,而二者单独作用对细胞增殖有轻微刺激作用 ,但与对照组无显著性差异。　　结论 :促炎因子TNF α和IL 1β的相互作用 ,可以诱导人平滑肌细胞凋亡。     

Analysis of T helper cell responses during infection with Leishmania amazonensis

Most inbred strains of mice are susceptible to Leishmania amazonensis infection and develop progressive cutaneous lesions. However, the role of Th subsets in the disease and the molecular basis of pathogenesis are unclear. To address this issue, we examined the frequency of cytokine-producing CD4+ T cells and the profile of alphabeta T cell receptor (TCR) usage in infected BALB/c mice. At different infection stages, CD4+ cells of draining lymph nodes contained comparable frequencies of Th1 and Th2 cells, produced comparable levels of interleukin-4 (IL-4) and interferon-gamma in vitro, and showed no significant bias in aalphabetaTCR usage. However, T cells became highly polarized to a Th2 phenotype (IL-4+, IL-10+) within a few cycles of in vitro restimulation. These Th2 cells preferentially expressed Valpha2, Vbeta4, or Vbeta8.1/8.2, and significantly exacerbated disease in cell-transferred mice. Thus, unlike a Th2-dominant phenotype seen in L. major infection, a mixed Th1/Th2 response can be maintained in L. amazonensis-infected mice via an as-yet-unidentified mechanism.     

Measuring oxygen saturation in retinal and choroidal circulations in rats using visible light optical coherence tomography angiography

Visible light optical coherence tomography (vis-OCT) has demonstrated its capability of measuring vascular oxygen saturation (sO₂) in vivo. Enhanced by OCT angiography, the signal from microvasculature can be further isolated and directly used for sO₂ extraction. In this work, we extended the theoretical formulation for OCT angiography-based oximetry by incorporating the contribution from motion contrast enhancement. We presented a new method to eliminate the associated confounding variables due to blood flow. First, we performed in vitro experiments to verify our theory, showing a stable spectral derivative within the selected wavelength bands for sO₂ extraction. Then, we tested our method in vivo to measure retinal sO₂ in rats inhaling different gas mixtures: normal air, 5% CO₂, pure O₂, and 10% O₂. Absolute sO₂ values in major arterioles and venules in the retinal circulation can be accurately measured. In addition, we demonstrated the relative changes of sO₂ can be measured non-invasively from choriocapillaris immediately underneath the retinal pigmented epithelium (RPE) in rodents.OCIS codes: (110.4500) Optical coherence tomography, (170.1460) Blood gas monitoring, (170.2655) Functional monitoring and imaging, (170.6480) Spectroscopy, speckle     

Coal fly ash is a major carbon flux in the Chang Jiang (Yangtze River) basin

Fly ash—the residuum of coal burning—contains a considerable amount of fossilized particulate organic carbon (FOC_ash) that remains after high-temperature combustion. Fly ash leaks into natural environments and participates in the contemporary carbon cycle, but its reactivity and flux remained poorly understood. We characterized FOC_ash in the Chang Jiang (Yangtze River) basin, China, and quantified the riverine FOC_ash fluxes. Using Raman spectral analysis, ramped pyrolysis oxidation, and chemical oxidation, we found that FOC_ash is highly recalcitrant and unreactive, whereas shale-derived FOC (FOC_rock) was much more labile and easily oxidized. By combining mass balance calculations and other estimates of fly ash input to rivers, we estimated that the flux of FOC_ash carried by the Chang Jiang was 0.21 to 0.42 Mt C⋅y⁻¹ in 2007 to 2008—an amount equivalent to 37 to 72% of the total riverine FOC export. We attributed such high flux to the combination of increasing coal combustion that enhances FOC_ash production and the massive construction of dams in the basin that reduces the flux of FOC_rock eroded from upstream mountainous areas. Using global ash data, a first-order estimate suggests that FOC_ash makes up to 16% of the present-day global riverine FOC flux to the oceans. This reflects a substantial impact of anthropogenic activities on the fluxes and burial of fossil organic carbon that has been made less reactive than the rocks from which it was derived.

Fossil particulate organic carbon (FOC) is a geologically stable form of carbon that was produced by the ancient biosphere and then buried and stored in the lithosphere; it is a key player in the geological carbon cycle (1–7). Uplift and erosion liberate FOC from bedrock, delivering it to the surficial carbon cycle. Some is oxidized in sediment routing systems, but a portion escapes and can be transported by rivers to the oceans (5, 8–10). Oxidation of FOC represents a long-term atmospheric carbon source and O₂ sink, whereas the reburial of FOC in sedimentary basins has no long-term net effect on atmospheric CO₂ and O₂ (1, 9, 11). Exhumation and erosion of bedrock provide a natural source of FOC (2, 8), which we refer to as FOC_rock. Human activities have introduced another form of FOC from the mining and combustion of coal. Burning coal emits CO₂ to the atmosphere but also leaves behind solid waste that contains substantial amounts of organic carbon (OC) that survives high-temperature combustion (12–14). This fossil-fuel-sourced carbon represents a poorly understood anthropogenic flux in the global carbon cycle; it also provides a major source of black carbon, which is a severe pollutant and climate-forcing agent (12–15).Previous studies sought to quantify black carbon in different terrestrial and marine environments and to distinguish fossil fuel versus forest fire sources (14–18). In this study, we focused on fly ash—the material left from incomplete coal combustion. As a major fossil fuel, coal supplies around 30% of global primary energy consumption (19, 20). Despite efforts to capture and utilize fly ash, a fraction enters soils and rivers; the resulting fossil OC from fly ash (FOC_ash) has become a measurable part of the contemporary carbon cycle (14). FOC_ash is also referred to as “unburned carbon” in fly ash (21–25); it provides a useful measure of combustion efficiency and the quality of fly ash as a building material (e.g., in concrete) (23–26). Industrial standards of FOC_ash content in fly ash have been established for material quality assurance (23, 24, 26, 27). However, the characteristics and fluxes of FOC_ash released to the environment, and how these compare to FOC_rock from bedrock erosion, remain less well understood.To fill this knowledge gap, we examined the Chang Jiang (Yangtze River) basin in China—a system that allowed us to evaluate the influence of FOC_ash on the carbon cycle at continental scales. In the 2000s, China became the largest coal-consuming country in the world, with an annual coal consumption of over 2,500 Mt, equating to ∼50% of worldwide consumption (19, 20, 28). Coal contributed over 60% of China’s national primary energy consumption through the 2000s. A significant portion of this coal (approximately one-third) was consumed in the Chang Jiang (CJ) basin, where China’s most populated and economically developed areas are located (29). Significant amounts of fly ash and FOC_ash continue to be produced and consumed in the CJ basin. To determine the human-induced FOC_ash flux, we investigated the FOC_ash cycle in the CJ basin. We characterized OC in a series of samples including fly ash, bedrock sedimentary shale, and river sediment through multiple geochemical analyses. We then estimated the CJ-exported FOC_ash flux and evaluated how human activities modulated FOC transfer at basin scales. We found that in the CJ basin, coal combustion and dam construction have conspired to boost the FOC_ash flux and reduce the FOC_rock flux carried by the CJ; as a result, these two fluxes converged over an interval of 60 y.     

无醋酸盐血液透析临床应用研究

本文对18例常规透析患者进行了无醋酸盐透析(AFHD)治疗研究,并以同期18例醋酸盐透析(AHD)患者作为对照组。结果表明,AFHD对中小分子物质以及β_2-m的清除与AHD比较无差异(P>0.05).应用KT/V,PCR,TACurca评价透析效果,证明透析充分.AHD后TNF及IL-6基因表达显著高于AFHD,TGF-β组间无差异,AHD后CD_4升高,而AFHD后CD_(?)降低。两组患者透析后SOD均降低。AFHD对磷的清除、无低氧血症,以及纠正代谢性酸中毒均优于AHD,副作用少.     

Antimicrobial Activity of Platelet‐Rich Plasma and Other Plasma Preparations Against Periodontal Pathogens

Background: In addition to releasing a pool of growth factors during activation, platelets have many features that indicate their role in the anti‐infective host defense. The antimicrobial activities of platelet‐rich plasma (PRP) and related plasma preparations against periodontal disease–associated bacteria were evaluated. Methods: Four distinct plasma fractions were extracted in the formulation used commonly in dentistry and were tested for their antibacterial properties against three periodontal bacteria: Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum. The minimum inhibitory concentration of each plasma preparation was determined, and in vitro time‐kill assays were used to detect their abilities to inhibit bacterial growth. Bacterial adhesion interference and the susceptibility of bacterial adherence by these plasma preparations were also conducted. Results: All plasma preparations can inhibit bacterial growth, with PRP showing the superior activity. Bacterial growth inhibition by PRP occurred in the first 24 hours after application in the time‐kill assay. PRP interfered with P. gingivalis and A. actinomycetemcomitans attachment and enhanced exfoliation of attached P. gingivalis but had no influences on F. nucleatum bacterial adherence. Conclusions: PRP expressed antibacterial properties, which may be attributed to platelets possessing additional antimicrobial molecules. The application of PRP on periodontal surgical sites is advisable because of its regenerative potential and its antibacterial effects.     

The influences of position and forced respiratory maneuvers on spinal stability muscles

[Purpose] The purposes of this study were to investigate the influences of position on %MVIC of spinal stability muscles to establish for the most effective breathing pattern for activation of spinal stability muscles in order to provide an additional treatment method for use in spinal stability exercise programs. [Subjects and Methods] Thirty-three healthy subjects performed quiet breathing and four different forced respiratory maneuvers (FRM); [pursed lip breathing (PLB), diaphragmatic breathing (DB), combination breathing (CB) and respiration muscle endurance training (RMET)] in both standing and sitting positions. %MVIC of them (the multifidus (MF), erector spinae (ES), internal oblique/transversus abdominis (IO/TrA), external oblique (EO), rectus abdominis (RA) measured. [Results] IO/TrA, MF and EO showed greater activation in standing than in sitting, while RA and ES showed greater activation in sitting than in standing. RMET induced significantly greater activation of spinal stability muscles then other breathing patterns. %MVIC changes of muscle activities induced by FRM were independent of position with a few exceptions. [Conclusion] The increased respiratory demands of FRM induced greater activation of spinal stability muscles than QB. RMET was found to be the most effective breathing pattern for increasing the activation of the spinal stability muscles.Key words: Spinal stability muscles, Position, Forced respiratory maneuvers     

Osteocytic Sclerostin Expression in Alveolar Bone in Rats With Diabetes Mellitus and Ligature‐Induced Periodontitis

Background: Osteocytic sclerostin inhibits bone formation, and its expression is stimulated by tumor necrosis factor (TNF)‐α. This study investigates sclerostin and TNF‐α expression in rats with diabetes mellitus (DM) and periodontitis. Methods: Rats were divided into control (C), periodontitis (P), and DM + periodontitis (DP) groups. After induction of DM by streptozotocin, periodontitis was induced by ligature. At day 0 (control) and at days 3 and 20 after induction of periodontitis, alveolar bone, osteoclasts, osteoid area, and TNF‐α and sclerostin expression were evaluated. Results: The distance between the cemento‐enamel junction and the alveolar bone crest of the DP group was longer than that of the P group at day 20 after induction of periodontitis, but the number of osteoclasts was not different. Osteoid area decreased in both the P and DP groups by day 3, but whereas sustained osteoid suppression was observed in the DP group at day 20, osteoid formation was increased in the P group. The number of sclerostin‐positive osteocytes increased in both groups at day 3, but the increased number of sclerostin‐positive osteocytes was maintained only in the DP group through day 20. The number of TNF‐α–positive cells increased more in the DP group than in the P group. Conclusions: Enhanced alveolar bone loss, suppressed bone formation, and prevalent TNF‐α expression were characteristic of the DP group compared with the P group. Suppressed bone formation in the DP group was observed simultaneously with increased sclerostin and TNF‐α expression. These results suggest that upregulated osteocytic sclerostin expression in periodontitis accompanied by DM may play a role in suppressed bone formation.     

The Canadian clinician-scientist training program must be reinstated

Clinical investigators within the Canadian and international communities were shocked when the Canadian Institutes of Health Research (CIHR) announced that their funding for the MD/PhD program would be terminated after the 2015–2016 academic year. The program has trained Canadian clinician-scientists for more than two decades. The cancellation of the program is at odds with the CIHR’s mandate, which stresses the translation of new knowledge into improved health for Canadians, as well as with a series of internal reports that have recommended expanding the program. Although substantial evidence supports the analogous Medical Scientist Training Program in the United States, no parallel analysis of the MD/PhD program has been performed in Canada. Here, we highlight the long-term consequences of the program’s cancellation in the context of increased emphasis on translational research. We argue that alternative funding sources cannot ensure continuous support for students in clinician-scientist training programs and that platform funding of the MD/PhD program is necessary to ensure leadership in translational research.The clinician-scientist community was shocked in June when the Canadian Institutes of Health Research (CIHR) announced that its funding for the MD/PhD program would be terminated. In a letter to MD/PhD program directors at Canadian medical schools, the CIHR cited budgetary constraints as the primary motivation for the cancellation of the program, which, at $1.8 million (all figures are in Canadian dollars), constitutes approximately 0.15% of the agency’s 2015 budget. Despite several internal reports that have recommended expanding clinical and translational research programs, and contrary to the CIHR’s own mandate, the CIHR has not yet outlined a new approach to clinician-scientist trainee program funding. Moreover, despite substantial evidence supporting American MD/PhD programs, no parallel evaluation of the MD/PhD program has been performed within Canada that would justify this funding decision (1). The cancellation of this program represents a blow to Canadian and international medical research.     

Case-Control Study of the Risk Factors for Acquisition of Pseudomonas and Proteus Species during Tigecycline Therapy

Tigecycline is an important agent in clinical practice because of its broad-spectrum activity. However, it has no activity against Pseudomonas or Proteus species. We conducted a case-control study to analyze risk factors for the acquisition of Pseudomonas or Proteus spp. during tigecycline therapy. Placement of suction drainage at infected wound sites, ICU stay, and neurologic disease were identified as independent risk factors for the acquisition of Pseudomonas and Proteus spp.