Variations in chlorophyll content, stomatal conductance, and photosynthesis in Setaria EMS mutants

Chlorophyll (Chl) content,especially Chl b content,and stomatal conductance (G_s) are the key factors affecting the net photosynthetic rate (P_n).Setaria italica,a diploid C_4 panicoid species with a simple genome and high transformation efficiency,has been widely accepted as a model in photosynthesis and drought-tolerance research.The current study characterized Chl content,G_s,and P_n of 48 Setaria mutants induced by ethyl methanesulfonate.A total of 24,34,and 35 mutants had significant variations in Chl content,G_s,and P_n,respectively.Correlation analysis showed a positive correlation between increased G_s and increased P_n,and a weak correlation between decreased Chl b content and decreased P_n was also found.Remarkably,two mutants behaved with significantly decreased Chl b content but increased P_n compared to Yugu 1.Seven mutants behaved with significantly decreased G_s but did not decrease P_(n )compared to Yugu 1.The current study thus identified various genetic lines,further exploration of which would be beneficial to elucidate the relationship between Chl content,G_s,and P_n and the mechanism underlying why C_4 species are efficient at photosynthesis and water saving.

模拟增温对植物叶片δ^(13)C值的影响:全球Meta分析

温室气体大量排放导致的全球变暖是最为关注的环境问题之一,这会直接影响植物的生长与发育进而影响群落组成乃至生态系统的结构和功能。水分利用效率作为植物叶片通过光合作用调节水分生理过程的指标,是联系生态系统碳循环与水循环关系的关键,反映了植被生态系统对立地环境快速调整和资源变化的适应策略,是当前全球变化研究中的重点。植物叶片碳稳定同位素比值(δ^(13)C)是反映植物长期水分利用效率的关键指标,但全球气候变暖对植物叶片δ^(13)C值的影响仍存在较大争议。该研究利用Meta分析整合全球范围内51份相关研究文献中的371组数据,较为系统地评估模拟增温对植物叶片δ^(13)C及其生理生态指标的影响。结果表明,模拟增温能够使叶片δ^(13)C值显著升高0.6%(P<0.001),同时对叶片呼吸速率R_(d)、气孔导度G_(s)、净光合作用速率P_(n)、碳C的效应值分别为0.237、0.062、-0.140、-0.019 (P<0.05)。模拟增温处理在增强植物光合作用的同时提高了叶片呼吸速率(R_(d)),导致光合产物不断被消耗、叶片碳(C)降低,最终使叶片P_(n)降低并且叶片δ^(13)C产生富集现象。通过进一步对影响因素分析发现,叶片δ^(13)C值对增温的响应主要受增温时间、高程和年均气温等控制(相对重要性指数分别为1.00、0.97和0.92)。另外,模拟增温时选用不同的增温模式对叶片δ^(13)C值也具有显著不同的影响,采用红外线加热、土柱置换和电缆增温等方法对叶片δ^(13)C值具有正向促进作用(效应值分别为0.70、0.44和0.35),而采用遮阳屏与开顶箱增温等方法具有负向作用(效应值分别为-0.17和-0.09)。研究结论对于深入理解全球变化背景下植物水分利用的响应特征具有重要的理论意义,以期为今后该领域的植物生长研究提供理论依据和有效支撑。

Response of stomatal conductance of two tree species to vapor pressure deficit in three climate zones

Stomatal behavior is a central topic of plant ecophysiological research under global environmental change. However, the physiological mechanism controlling the response of stomata to vapor pressure deficit （VPD） or relative humidity （RH） has been inadequately understood till now. In this study, responses of stomatal conduc- tance （gs） to VPD in two species of trees （Fraxinus chinensis Roxb., Populus alba L. var. pyramidalis Bge.）in three different climate zones （Jinan with typical warm humid/semi-humid climate, Urumqi with temperate continental arid climate and Turpan with extreme arid desert climate） were measured. Levels of two phytohormones （abscisic acid, ABA; indole-3-acetic acid, IAA） in the leaves of the two tree species at these three sites were also measured by high performance liquid chromatography. The results showed that the responses of gs to an increasing VPD in these two tree species at the three sites had peak curves which could be fitted with a Log Normal Model （gs=a.exp（-O.5（In（DIc）lb）2）. The VPD/RH values corresponding to the maximum g, can be calculated using the fitting models for the two tree species in the three sites. We found that the calculated g, -VPD correlated nega- tively with relative air humidity in the three sites during the plant growth period （April to October 2010）, which showed the values of g,-max-VPD were related to the climate conditions. The prevailing empirical stomatal model （Leuning model） and optimal stomatal behavior model could not properly simulate our measured data. The water use efficiency in the two tree species did not show obvious differences under three very different climatic conditions, but the highest gs, photosynthetic and transpiration rates occurred in P. alba var. of Turpan. The sensitivity in re- sponse of g~ to VPD in leaves of the two trees showed positive correlations with the concentration of ABA, which implied that ABA level could be used as an indicator of the sensitivity of stomatal response to VPD. Our results confirmed that the prediction of the response of gs to VPD might be incomplete in the two current popular models. Therefore, an improved g, model which is able to integrate the results is needed. Also, the stomatal response mechanism of single peak curves of g~ to VPD should be considered.

Gas flaring cause shifts in mesophyll and stomatal functional traits of Betula pubescens Ehrh.

In petroleum-producing territories of West Siberia(Russia),oil well gas flares have a thermal effect on nearby plant communities.Such communities can be used as models for studying plant acclimation to global warming.In the present study on the effect of the hydrothermal regime at the flare sites on mesophyll and stomatal functional traits of Betula pubescens,leaves were collected from trees at250 m(control site[CS]),200,150 and 100 m(maximum impact site[MIS])from a flare.From the CS to MIS site,the average annual air temperature increased by 0.5℃and bog water level decreased by 17 cm.On plants from the MIS,stomata were 16%smaller and density was 20%lower compared to those at the CS,resulting in lower maximum stomatal conductance in plants from the MIS(mean±SE:MIS 0.84±0.05 mol·m^(-2)s^(-1),CS 1.24±0.06 mol·m^(-2)s^(-1);F=12.6,P<0.01).Mesophyll cell volume was 1.9 times lower at MIS than at CS.Chloroplast numbers per cell also declined with distance from the flares,from 21(MIS)to18(CS;F=15.6,P<0.001),and chloroplast volume was 24%higher at the CS,whereas the number of mesophyll cells and chloroplasts numbers per unit leaf area were 1.9 and 1.8 times higher at the MIS than at the CS,respectively.As a result,leaves from the MIS had a large total mesophyll cell(Ames/A)and chloroplast(Achl/A)surface area per unit leaf area,resulting in a 46%increase in mesophyll conductance in plants from the MIS.Thus,structural changes in leaf epidermis consisted of a decrease in stomatal size and number,could lower transpiration losses with higher temperatures and less water.To compensate for the reduction in leaf conductance due to a decrease in stomatal conductance under these conditions,an increase in the number of mesophyll cells and chloroplasts per unit area provides a greater gas-exchange area and mesophyll conductance.

Drought-Induced Changes in Xylem Sap pH, ABA and Stomatal Conductance

Upstream signals potentially regulating evaporation and stomatal conductance wereinvestigated using 6-8-leaf-old maize (Zea may L.) seedlings which were grown in agreenhouse. Pressure chamber was used to measure leaf water potential and to collectxylem sap. The pH of xylem sap in stems was higher than that in root, and the abscisicacid (ABA) concentration in stems was the highest in well-watered seedlings. The ABAconcentration and pH of xylem sap in roots, stems and leaves increased, and the ABAconcentration in leaves reached the maximum during drought stress. The treatment ofroots with exogenous ABA solution (100molL-1) increased xylem sap ABA concentration inall organs measured, and induced stomatal closure, but did not change ABA distributionamong organs of maize seedlings. The combined effects of external pH buffer on pH, ABAof xylem sap and stomatal behavior indicated that pH, as a root-source signal to leavesunder drought stress, regulated stomatal closure through accumulating ABA in leaves orguard cells.

Hydraulic role in differential stomatal behaviors at two contrasting elevations in three dominant tree species of a mixed coniferous and broad-leaved forest in low subtropical China

Quantifying the variation in stomatal behavior and functional traits of trees with elevation can provide a better understanding of the adaptative strategies to a changing climate. In this study, six water-and carbon-related functional traits were examined for three dominant tree species, Schima superba, Pinus massoniana and Castanopsis chinensis, in a mixed coniferous and broad-leaved forest at two elevations(70 and 360 m above sea level,respectively) in low subtropical China. We hypothesized that trees at higher elevations would develop more efficient strategies of stomatal regulations and greater water transport capacity to cope with more variable hydrothermal conditions than those at lower elevations. Results show that the hydraulic conductivity did not differ between trees at the two elevations, contrary to our expectation. The C. chinensis trees had greater values of leaf mass per unit area(LMA), and the S. superba and C. chinensis trees had greater values of wood density(WD),relative stem water content(RWC), and ratio of sapwood area to leaf area(Hv) at the 360-m elevation than at 70-m elevation. The mean canopy stomatal conductance was greater and more sensitive to vapor deficit pressure at360 m than at 70 m for both S. superba and C. chinensis, while stomatal sensitivity did not differ between the two contrasting elevations for P. massoniana. The midday leaf water potential(ψL) in P. massoniana was significantly more negative at 360 m than at 70 m, but did not vary with increasing elevation in both S. superba and C. chinensis.Variations in Hvcan be related to the differential stomatal behaviors between the two elevations. The variations of stomatal behavior and ψLwith elevation suggested the isohydric strategy for the two broad-leaved species and the anisohydric strategy for the conifer species. The species-specific differences in LMA, WD, RWC, and Hvbetween the two elevations may reflect conservative resource use strategies at the higher elevation. Our findings revealed a close relationship between hydraulic and stomatal behavior and may help better understand the functional responses of forests to changing environmental conditions.

Study on Transpiration and Stomatal Conductance Characteristics of C3 and C4 Plant

The transpiration experiment was done under greenhouse conditions with a C3 plant sweet pepper （Capsicum annuum Linn.） and two C4 plants, sorghum （Sorghum bicolor L.Moench） and maize （Zea mays Linn.）. Three species were irrigated with three different water treatment levels of 100%, 66% and 33% which gave a comparison of tolerance and adaptation to irrigation and two different levels of water stress. The measurements of transpiration rate and stomatal conductance were done between 8.00 a.m. and 16.00 p.m. with measurements about each 1.5 h with an infrared gas analyzer. The results showed that Z. mays probably due to a higher leaf area had very low values and was significantly different （LSD pairwise comparison） from C. annuum and S. bicolor. The hypotheses that C4 plants and C3 plants have different transpiration rates and stomatal conductance could not be shown with the results. However, the hypotheses that for the same species, the highest values in transpiration rate and stomatal conductance were with the 100% irrigation treatment and the lowest values were with the 33% irrigation treatment could be accepted due to the results of this trial.

Comparison of the S-, N- or P-Deprivations’ Impacts on Stomatal Conductance, Transpiration and Photosynthetic Rate of Young Maize Leaves

Seven-day-old maize (Zea mays) plants were grown hydroponically for ten days in deprived nutrient solutions against the corresponding control grown under full nutrition;the effects of S-, N- or P-deprivation on laminas’ mean stomatal conductance (gs), transpiration rate (E) and photosynthetic rate (A) were monitored, along with the impact on the laminas’ total dry mass (DM), water amount (W), length and surface area (Sa). Furthermore, a time series analysis of each parameter’s response ratios (Rr), i.e. the treatment’s value divided by the corresponding control’s one, was performed. Under S-deprivation, the Rr of laminas’ mean gs, E, and A presented oscillations within a ±15% fluctuation zone, notably the “control” zone, whilst those of laminas’ total DM, water amount, surface area, and length included oscillation during the first days and deviation later on, presenting deviation during d10. Under the N-deprivation conditions all Rr time courses except the A one, included early deviations from the control zone without recovering. The deviation from the control zone appeared at d4. Under P-deprivation, all Rr time courses represented oscillations within the control zone. P-deprivation’s patterns resembled those of S-deprivation. Compared to the one of the S-deprivation, the P-one’s oscillations took place within a broader zone. Linear relationships among the various Rr patterns were found between gs-E, gs-A, E-A, DM-W and DM-Sa. In conclusion, the impact of P-deprivation appeared in an early stage and included an alleviation action, the one of N-deprivation appeared early with no alleviation action, whilst that of S-deprivation appeared later, being rather weaker when compared to the impact of the P-deprivation’s impact.

Responses of leaf stomatal and mesophyll conductance to abiotic stress factors

Plant photosynthesis assimilates CO_(2)from the atmosphere,and CO_(2)diffusion efficiency is mainly constrained by stomatal and mesophyll resistance.The stomatal and mesophyll conductance of plants are sensitive to abiotic stress factors,which affect the CO_(2)concentrations at carboxylation sites to control photosynthetic rates.Early studies conducted relevant reviews on the responses of stomatal conductance to the environment and the limitations of mesophyll conductance by internal structure and biochemical factors.However,reviews on the abiotic stress factors that systematically regulate plant CO_(2)diffusion are rare.Therefore,in this review,the rapid and long-term responses of stomatal and mesophyll conductance to abiotic stress factors(such as light intensity,drought,CO_(2)concentration and temperature)and their physiological mechanisms are summarized.Finally,future research trends are also investigated.

AuNP@Co_(3)(HITP)_(2)-CNT纳米结构的制备及电化学传感性能

利用一步水热法和化学还原法制备了基于金纳米颗粒负载Co_(3)(HITP)_(2)-碳纳米管(AuNP@Co_(3)(HITP)_(2)-CNT)的纳米复合材料。利用X射线光电子能谱仪(XPS)和扫描电子显微镜(SEM)对其表面微观形貌和元素组成进行表征。构建了前列腺特异性抗原(PSA)/牛血清蛋白(BSA)/PSA抗体(Ab)/AuNP@Co_(3)(HITP)_(2)-CNT/玻碳电极(GCE)电化学免疫传感器,并对PSA进行了检测,用循环伏安法(CV)、差分脉冲伏安法(DPV)和电化学阻抗谱(EIS)对其进行电化学性能分析测试。实验结果表明:基于AuNP@Co_(3)(HITP)_(2)-CNT纳米复合材料的电化学免疫传感器对PSA有较宽的检测范围,可达40 fg/mL~100 ng/mL,同时具有较好的特异性、稳定性和可重复性。

A Modification of LiMn2O4 by Ionic Conductive Agent and Electronic Conductive Agent Coating

Carbon was used as electronic conductive agent, and metasilicic acid lithium (Li2SiO3) as ionic conductive agent, the two factors were investigated cooperatively. We evaluated their effect by using spherical spinel LiMn2O4 which prepared ourselves as cathode material. Then Li2SiO3/carbon surface coating on LiMn2O4 (LMO/C/LSO) which Li2SiO3 inside and carbon/Li2SiO3 coated LiMn2O4 (LMO/LSO/C) were prepared, All of materials were characterized by X-ray diffraction (XRD) and electrochemical test;spherical LiMn2O4 was characterized by scanning electron microscopy (SEM);and coated materials were characterized by transmission electron microscopy (TEM). While uncoated spinel LiMn2O4 maintained 72% of capacity in 60 cycles by the rate of 0.2C, and LMO/LSO/C showed the best electrochemical performance, 89% of the initial capacity remained after 75 cycles at 0.2C. Furthermore, the rate performance of LMO/LSO/C also improved obviously, about 30 mAh·g-1 of capacity attained at the rate of 5C, higher than LMO/C/LSO and bare LiMn2O4.

Distribution Profiles and Interrelations of Stomatal Conductance, Transpiration Rate and Water Dynamics in Young Maize Laminas under Nitrogen Deprivation

Seven-day-old maize (Zea mays) plants were grown hydroponically for ten days in N-deprived nutrient solution. The distribution profiles according to the position on the stem of the –N laminas stomatal conductance, transpiration rate, photosynthetic rate (1st-group) were monitored, along with the corresponding profiles of dry mass, water amount, water content, length, surface area, and specific surface area (2nd-group), relative to control. In the uppermost –N laminas, the changes within a parameter of the 1st-group were significantly higher and of the 2nd-group significantly lower than the control, respectively. Correlations of the corresponding values among the parameters of the 1st-or 2nd-group were linear. The parameters between groups correlated non-linearly. Transpiration rate was divided by the lamina’s dry mass correlated with surface area in a power-type function. The slopes of the response ratios linear relations between the various pairs of parameters could be used for simulation of a lamina’s response to the deprivation.

维生素C对聚合物/金属导电复合材料电磁屏蔽稳定性的影响

采用熔融共混法制备了动态硫化热塑性弹性体(TPV)/镀镍(Ni)玻璃纤维(NCGF)/维生素C(VC)导电复合材料TPV/NCGF_(VC),系统研究了VC对该复合材料老化前后的微观形貌、分子结构及力学性能的影响,探讨了VC对Ni金属网络的选择性保护作用机制。结果表明,在TPV/NCGF复合材料中添加VC能够有效抑制老化过程中Ni导电网络的氧化,从而使复合材料表现出稳定的导电性和电磁屏蔽性能,其中电磁屏蔽效能保持率超过90%;在纯TPV基体中引入VC后,VC能有效抑制老化后TPV分子链的断裂;在TPV/NCGF_(VC)复合材料的老化过程中,VC优先与Ni网络发生还原反应,将NCGF表面Ni层因氧化生成的Ni离子(Ni^(2+))还原为单质Ni(Ni^(0)),表明VC对Ni金属网络具有选择性保护作用。

Verification of the stomatal conductance of Nebbiolo grapevine

Wine is one of the most important Italian export products,and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007,a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza d’Alba,near Cuneo,Italy. Using a gauge of trade gases and some other instruments,we recorded the stomatal conductance and also some physiological parameters useful for estimating the dependence of stomatal conductance on environmental variables. The goal of this experiment was improving the parameterization of grapevine evapotranspiration through the assessment of the stomatal conductance and,in particular,of the functional dependence of the stomatal conductance on the following variables:the photosynthetically active radiation,the atmospheric temperature,the atmospheric moisture deficit,and the carbon dioxide concentration. The observations allowed us to check and,in some cases,to adapt the existing general parameterizations found in literature. The results showed some significant differences with the existing parameterizations concerning the atmospheric temperature,the atmospheric moisture deficit,and the carbon dioxide concentration. The parameterizations obtained in this experiment,although referring to a specific plant and site(namely the Nebbiolo at Vezza d’Alba),could allow assessment of the best environmental conditions under which the Nebbiolo grapevine production is the best,and in future could be tested for other grapevines or climates.

闪光法测量C/C复合材料导热系数影响因素研究

C/C复合材料已在航空航天领域及原子能领域得到了广泛的应用,其工作温度可达1000℃以上。为对C/C复合材料导热系数进行测定,使用闪光法测定了C/C复合材料25℃至1000℃的热扩散系数和比热容,并对石墨喷敷、样品厚度、参比样品和修正模型的影响进行了研究。研究结果表明,为提高C/C复合材料热扩散系数测试准确度,样品应不喷敷石墨,测试结果使用渗射模型修正;为提高C/C复合材料比热容测试准确度,样品应均匀喷敷石墨,并使用石墨标准样品作为参比样品,测试结果使用Cowan模型修正。

Stomatal response of Pinus sylvestriformis to elevated CO2 concentrations during the four years of exposure

Four-year-old Pinus sylvestriformis were exposed for four growing seasons in open top chambers to ambient CO2 concentration (approx. 350 μmol·mol-1) and high CO2 concentrations (500 and 700 μmol·mol-1) at Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences at Antu Town, Jilin Province, China (42oN, 128oE). Stomatal response to elevated CO2 concentrations was examined by stomatal conductance (gs), ratio of intercellular to ambient CO2 concentration (ci/ca) and stomatal number. Reciprocal transfer experiments of stomatal conductance showed that stomatal conductance in high-[CO2]-grown plants increased in comparison with ambient-[CO2]-grown plants when measured at their respective growth CO2 concentration and at the same measurement CO2 concentration (except a reduction in 700 μmol·mol-1 CO2 grown plants compared with plants on unchambered field when measured at growth CO2 concentration and 350 μmol·mol-1CO2). High-[CO2]-grown plants exhibited lower ci/ca ratios than ambient-[CO2]-grown plants when measured at their respective growth CO2 concentration. However, ci/ca ratios increased for plants grown in high CO2 concentrations compared with control plants when measured at the same CO2 concentration. There was no significant difference in stomatal number per unit long needle between elevated and ambient CO2. However, elevated CO2 concentrations reduced the total stomatal number of whole needle by the decline of stomatal line and changed the allocation pattern of stomata between upper and lower surface of needle.

C/C多孔体的高温热处理对C/C-SiC复合材料摩擦磨损行为的影响

低密度C/C多孔体的结构与性能调控是制备具有优异摩擦磨损性能的C/C-SiC复合材料的关键。本研究采用化学气相渗积法制备了C/C多孔体,并对其进行2100℃高温热处理,再通过反应熔渗法制备了C/C-SiC复合材料,研究了C/C多孔体高温热处理对C/C-SiC复合材料微观结构、导热性能和摩擦磨损性能的影响。结果表明,经2100℃热处理的C/C多孔体孔隙率和石墨化程度增加,用其制备的C/C-SiC复合材料比C/C多孔体未经热处理的密度更大(2.22 g/cm^(3)),孔隙率由5.1%降低至3.4%, SiC陶瓷相含量比热处理前提高11.9%。石墨化程度越高,声子的平均自由程越大,因此其室温的导热率提升到3.1倍, 1200℃导热率提升到1.2倍。经过热处理的热解炭更软,摩擦面易形成连续且稳定的摩擦膜,因此摩擦系数更稳定,并且在测试载荷为3、6和9 N下磨损率均显著降低,下降幅度达到47.8%、41.9%和11.7%,平均摩擦系数分别为0.47、0.38和0.39。综上所述,对C/C多孔体进行高温热处理可使C/C-SiC复合材料的导热性能提升,更耐磨并且表现出更稳定的摩擦系数。

CO_2, H_2O exchange and stomatal regulation of regenerated Camptotheca acuminata plantlets during ex vitro acclimatization

For finding the changes in CO2, H20 exchange and their stomatal regulation during ex vitro acclimatization of regenerated Camptotheca acuminata plantlets, the net photosynthesis rate （Pn）, respiration rate （Ro）, light compensation point （Lc） and light saturation point （Ls）, transpiration rate （Tr）, stomatal conductance （gs） and water use efficiency（WUE） were measured during 37 days of ex vitro acclimatization. The results showed that Pn sharply increased until 29 days, then slightly decreased. A substantial decrease in Lc and a substantial increase of Ls in the former two weeks were observed, indicating the light regime enlargement for effective leaf photosynthesis. Tr and gs abruptly decreased during the first week then linearly increased until 29days ex vitro acclimatization, reflecting the strong regulation effect of stomata on water changes of ex vitro acclimating plantlets. Stomatal regulation effect on CO2 exchange was different from that on water exchange, i.e. P, was almost independent of gs during the first week, while P. was significantly correlated with gs thereafter （i.e. dual patterns）. Different from dual patterns of gs-Pn relation, the Tr monotonously linearly increased with gs. Furthermore, WUE was almost independent on gs during the first week, while a marked decreasing tendency with gs was found thereafter. At the beginning of the acclimatization, WUE was mainly determined by photosynthetic capacity, while transpiration becomes a main determinant factor for WUE from 7 to 37 days＇ acclimatization.

糖尿病肾病合并糖尿病周围神经病变患者血清C肽水平及其与肾功能、神经传导速度的相关性

目的探讨糖尿病肾病(DN)合并糖尿病周围神经病变(DPN)患者血清C肽水平及其与肾功能、神经传导速度的相关性。方法选取121例DN患者,根据其是否合并DPN将其分为合并DPN组56例和单纯DN组65例,另选取同期40例健康体检者作为健康组。比较3组研究对象的空腹C肽(FCP)水平、餐后2 h C肽(2hPCP)水平、肾功能指标[血清尿素氮、血清肌酐、24 h尿蛋白]水平、右腓总神经运动神经传导速度(MNCV)和感觉神经传导速度(SNCV)。分析合并DPN组患者血清C肽水平与肾功能指标水平、神经传导速度的关系。结果合并DPN组的FCP、2hPCP水平均低于单纯DN组与健康组,单纯DN组的2hPCP水平低于健康组(均P<0.05),而健康组与单纯DN组的FCP水平差异无统计学意义(P>0.05)。合并DPN组的24 h尿蛋白、血清尿素氮、血清肌酐水平均高于单纯DN组与健康组,单纯DN组的上述指标均高于健康组(均P<0.05)。合并DPN组的MNCV、SNCV均慢于单纯DN组与健康组(均P<0.05),而健康组与单纯DN组的MNCV、SNCV差异均无统计学意义(均P>0.05)。合并DPN组患者的FCP、2hPCP水平与24 h尿蛋白、血清尿素氮、血清肌酐水平均呈负相关,与MNCV、SNCV均呈正相关(均P<0.05)。结论相比于单纯DN患者,合并DPN的DN患者的血清C肽水平降低、肾功能障碍程度更明显,且存在周围神经传导功能障碍。DN合并DPN患者的血清C肽水平与肾功能及周围神经传导障碍程度相关。

2型糖尿病合并周围神经病变病人血清Cys-C水平与神经传导参数的相关性

目的:分析血清胱抑素C(Cys-C)表达水平与2型糖尿病(T2DM)合并周围神经病变(DPN)病人神经传导参数的相关性。方法:选取2021年1月—2021年11月广汉市人民医院收治的118例T2DM病人,根据DPN并发情况将其分为合并DNP组(61例)和单纯T2DM组(57例)。比较两组一般资料、血清Cys-C水平及神经传导参数,分析血清Cys-C与神经传导参数的相关性,评估Cys-C与神经传导参数对T2DM病人DPN并发情况的预测效能。结果:两组性别、年龄、体质指数(BMI)、舒张压比较差异均无统计学意义(P>0.05),合并DNP组糖尿病病程明显长于单纯T2DM组(P<0.05),收缩压明显大于单纯T2DM组(P<0.05);合并DNP组血清Cys-C水平均明显高于单纯T2DM组(P<0.05),正中神经感觉传导速度(SCV)、正中神经运动传导速度(MCV)、腓总神经SCV、腓总神经MCV均明显低于单纯T2DM组(P<0.05)。Pearson相关性分析表明,T2DM合并DNP病人血清Cys-C水平与正中神经SCV、正中神经MCV、腓总神经SCV、腓总神经MCV均呈负相关(P<0.05);受试者工作特征(ROC)曲线分析显示,血清Cys-C、正中神经SCV、正中神经MCV、腓总神经SCV、腓总神经MCV预测T2DM病人并发DPN的AUC分别为0.749,0.819,0.872,0.821,0.836,联合诊断AUC可达到0.977,联合诊断价值更高。结论:T2DM合并DPN病人血清Cys-C水平呈明显上升,且存在上下肢感觉、运动神经传导受损情况,血清Cys-C及神经传导参数可作为T2DM病人并发DPN的参考指标。