The Association Between Phosphorylated Neurofilament Heavy Chain (pNF-H) and Small Fiber Neuropathy (SFN) in Patients with Impaired Glucose Tolerance.

INTRODUCTION: Small fiber neuropathy (SFN)-the early stage of diabetic peripheral neuropathy (DPN)-progresses gradually and is difficult to diagnose using neurophysiological tests. To facilitate the early diagnosis of SFN, biomarkers for SFN must be identified. The purpose of this study was to investigate the characteristics of SFN in prediabetic patients and the relationship between pNF-H and SFN. METHODS: 44 IGT patients (inpatients and outpatients) were selected at random. 33 healthy subjects served as controls. Data on clinical characteristics and laboratory parameters were collected. Quantitative sensory testing (QST), electromyography (EMG), and Sudoscan were performed, and pNF-H was measured by ELISA. RESULTS: 24 of the 44 patients with impaired glucose tolerance (IGT) were diagnosed with SFN according to the modified Toronto Diabetic Neuropathy Expert Group consensus criteria. The thermal sensory thresholds of the IGT-SFN group were significantly different from those of the CTRL group (p < 0.05), except for the heat pain threshold. The sensory nerve action potential (SNAP) of the sural nerve was 12.39 in the IGT-SFN group, which was significantly lower than those in the other groups. No significant difference in nerve conduction velocity (NCV) was observed among the three groups. The electrochemical skin conductance (ESC) in the IGT-SFN group was 69.78 ± 14.03uS, which was significantly lower than that in the CTRL group. The pNF-H in the IGT-SFN group was 170.6 (140.0, 223.6) pg/ml, which was significantly higher than those in the CTRL and IGT-non-SFN groups (76.55 and 64.7 pg/ml, respectively). Multivariate regression analysis demonstrated that pNF-H and 2h plasma glucose were independently correlated with SFN; the ORs (95% CI) were 1.429 (1.315, 1.924) and 2.375 (1.157, 4.837), respectively. CONCLUSIONS: Serum pNF-H may be associated with SFN in IGT patients, and serum pNF-H could therefore serve as a sensitive biomarker for the detection of SFN.

Correction to: The Association Between Phosphorylated Neurofilament Heavy Chain (pNF-H) and Small Fiber Neuropathy (SFN) in Patients with Impaired Glucose Tolerance.

In the original article, there was some error in Table 2. The correct table is given below.

[Effects of Short-term Exogenous Nitrogen and Carbon Input on Soil Respiration Under Changing Precipitation Pattern].

The responses of soil respiration to exogenous carbon (C) and nitrogen (N) inputs under changing precipitation patterns were explored via in-situ field experiments. In 2014, a typical temperate grassland on the Xilin River of Inner Mongolia was taken as the research site, and soil respiration was measured in the following treatments:addition of water alone (CK), addition of water + N fertilizer[CN, 2.5 g·(m2·a)-1], addition of water + labile C[CG, 24 g·(m2·a)-1], and addition of water + N fertilizer+ labile C[CNG, 2.5 g·(m2·a)-1+24 g·(m2·a) -1], and the correlations of soil respiration with soil temperature, soil moisture, soil dissolved organic C (DOC), and soil microbial biomass C (MBC) were analyzed. During the first water application event (FWE) with the frequency of natural precipitation, cumulative CO2 efflux over 168 hours significantly increased in the CG and CNG treatments, whereas there was no such change in the CN treatment. In addition, soil MBC contents in the CG and CNG treatments were significantly higher than that in the CK and CN treatments, and the correlation of average soil respiration rate with soil MBC content among these treatments was positively significant (P<0.05). In contrast with during the FWE, cumulative CO2 efflux over 168 hours and soil MBC content significantly decreased during the second water application event (SWE) with no natural precipitation (P<0.05), whereas soil DOC content significantly increased (P<0.05). The cumulative CO2 efflux over 168 hours significantly decreases in the CN and CG treatments (P<0.05).During both the water application events, soil respiration rate had a positive relationship with soil temperature and soil volume water content (P<0.05). Therefore, it is proposed that the distribution of natural precipitation influences soil water content, which controls the effects of exogenous C and N on soil respiration in semiarid grassland ecosystems.

[Effect of Irrigation Patterns on Soil CO2 and N2O Emissions from Winter Wheat Field in North China Plain].

The water-saving irrigation is the trend of modernized agriculture. This paper aimed to study the effect of water-saving irrigation on soil CO2 and N2O emissions. The field experiments were conducted under micro sprinkler irrigation of integrated water and fertilizer (MSI) and conventional flooding irrigation (FI) in winter wheat growth season in the west of North China Plain during 2013- 2014 using the static chamber method. This paper analyzed the seasonal variation of soil CO2and N2O emissions under MSI and FI, and then compared the soil CO2 and N2O emissions from treatments located in different vertical distance away from micro sprinkler pipe. Root exclusion was used to estimate the components of soil respiration and agricultural carbon sequestration intensity under MSI and FI in winter wheat field. The results indicated that: (1) The average soil CO2 emissions under MSI and FI were 418.19 mg (m² · h)⁻¹ and 372.14 mg · (m² · h)⁻¹ respectively with no significant difference, and cumulative CO2 emissions under MSI and FI were 2 150.6 g · m⁻² and 1 904.6 g · m⁻², respectively. (2) During returning green stage to harvest stage of winter wheat, the highest soil CO2 cumulative emissions were found at the closest site to the micro sprinkler irrigated pipes under MSI. However, there were no significant differences among spatial treatments. (3) Under MSI and FI, soil heterotrophic respiration (C) was 468.49 g · m⁻² and 427.31 g · m⁻², and the net primary productivity (3) was 1988.21 g · m⁻² and 1770.54 g · m⁻²; the carbon sink (C) during winter wheat growing season was 1 519.72 g · m⁻² and 1 343.24 g · m⁻², respectively. (4) The average N2O emissions under MSI and FI were 50.77 µg · (m² · h)⁻¹ and 28.81 µg · (m² · h)⁻¹ respectively with no significant difference. Cumulative N2O emission under MSI and FI was 272.67 mg · m⁻² and 154.08 mg · m⁻², respectively. (5) During returning green stage to harvest stage of winter wheat, the farther the distance away from the micro sprinkler irrigated pipes, the smaller the soil N2O emissions. Moreover, there were no significant differences among sptial treatment under MSI. Therefore, despite of the increase of soil CO2and N2O emissions, the intensity of carbon sink increased during the transformation from traditional flood irrigation to micro sprinkler irrigation in winter wheat fields.

[Responses of ecosystem carbon budget to increasing nitrogen deposition in differently degraded Leymus chinensis steppes in Inner Mongolia, China].

Based on a field manipulative nitrogen (N) addition experiment, the effects of atmospheric N deposition level change on the plant biomass and net primary productivity (NPP), soil respiration (Rs) and net ecosystem exchange (NEE) were investigated respectively in 2009 and 2010 in two differently degraded Leymus chinensis steppes in Inner Mongolia of China, and the difference in the response of NEE to equal amount of N addition [10 g x (M2 x a)(-1), MN] between the two steppes was also discussed. The results indicated that for the light degraded Leymus chinensis steppe (site A) , the average plant aboveground biomass (AGB) in MN treatment were 21.5% and 46.8% higher than those of CK in these two years. But for the moderate degraded Leymus chinensis steppe (site B), the N addition decreased the plant AGB and ANPP in 2009, while showed positive effects in 2010. N addition increased the belowground biomass (BGB) of the both sites and belowground NPP (BNPP) of site B in both years, but decreased the BNPP of site A in 2010. The increase of N input in the two steppes did not change the seasonal variation of Rs. The cumulative annual soil C emissions in MN treatment in site A showed an increase of about 14.6% and 25.7% of those in the CK respectively for these two years, while were decreased by about 10.4% and 11.3%, respectively in site B. The NEE of MN treatments, expressed by C, for the two steppes were 59.22 g x (m2 x a)(1) and 166.68 g x (m2 x a)(-1), as well as 83.27 g x (m2 x a)(-1) and 117.47 g x (m2 x a)(-1), respectively in these two years. The increments in NEE originated from N addition for these two years were 15.79 g x (M2 x a)(-1) and 82.94 g x (M2 x a)(-1) in site A and 74.54 g x (M2 x a)(-1) and 101.23 g x (M2 x a)(-1) in site B. The N input per unit could obtain greater C sink effect in the steppe with lower initial N level.

[Effects and mechanism of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem].

As a widespread natural phenomenon in the soil of middle and high latitude as well as high altitude, freeze-thawing cycles have a great influence on the nitrogen cycle of terrestrial ecosystem in non-growing season. Freeze-thawing cycles can alter the physicochemical and biological properties of the soil, which thereby affect the migration and transformation of soil nitrogen. The impacts of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem found in available studies remain inconsistent, the mechanism is still not clear, and the research methods also need to be further explored and innovated. So it is necessary to sum up and analyze the existing achievements in order to better understand the processes of soil nitrogen cycle subjected to freeze-thawing cycles. This paper reviewed the research progress in China and abroad about the effects and mechanisms of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem, including mineralization, immobilization, nitrification and denitrification, N leakage and gaseous loss, and analyzed the deficiencies of extant research. The possible key research topics that should be urgently paid more attention to in the future were also discussed.

[Microbial response mechanism for drying and rewetting effect on soil respiration in grassland ecosystem: a review].

As one of the most important and wide distribution community type among terrestrial ecosystems, grassland ecosystem plays a critical role in the global carbon cycles and climate regulation. China has extremely rich grassland resources, which have a huge carbon sequestration potential and are an important part of the global carbon cycle. Drying and rewetting is a common natural phenomenon in soil, which might accelerate soil carbon mineralization process, increase soil respiration and exert profound influence on microbial activity and community structure. Under the background of the global change, the changes in rainfall capacity, strength and frequency would inevitably affect soil drying and wetting cycles, and thus change the microbial activity and community structure as well as soil respiration, and then exert important influence on global carbon budget. In this paper, related references in recent ten years were reviewed. The source of soil released, the trend of soil respiration over time and the relationship between soil respiration and microbial biomass, microbial activity and microbial community structure during the processes of dry-rewetting cycle were analyzed and summarized, in order to better understand the microbial response mechanism for drying and rewetting effecting on soil respiration in grassland ecosystem, and provide a certain theoretical basis for more accurate evaluation and prediction of future global carbon balance of terrestrial ecosystems and climate change.

Facilitating effects of berberine on rat pancreatic islets through modulating hepatic nuclear factor 4 alpha expression and glucokinase activity.

AIM: To observe the effect of berberine on insulin secretion in rat pancreatic islets and to explore its possible molecular mechanism. METHODS: Primary rat islets were isolated from male Sprague-Dawley rats by collagenase digestion and treated with different concentrations (1, 3, 10 and 30 micromol/L) of berberine or 1 micromol/L Glibenclamide (GB) for 24 h. Glucose-stimulated insulin secretion (GSIS) assay was conducted and insulin was determined by radioimmunoassay. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate cytotoxicity. The mRNA level of hepatic nuclear factor 4 alpha (HNF4alpha) was determined by reverse transcription polymerase chain reaction (RT-PCR). Indirect immunofluorescence staining and Western blot analysis were employed to detect protein expression of HNF4alpha in the islets. Glucokinase (GK) activity was measured by spectrophotometric method. RESULTS: Berberine enhanced GSIS rather than basal insulin secretion dose-dependently in rat islets and showed no significant cytotoxicity on islet cells at the concentration of 10 mumol/L. Both mRNA and protein expressions of HNF4alpha were up-regulated by berberine in a dose-dependent manner, and GK activity was also increased accordingly. However, GB demonstrated no regulatory effects on HNF4alpha expression or GK activity. CONCLUSION: Berberine can enhance GSIS in rat islets, and probably exerts the insulinotropic effect via a pathway involving HNF4alpha and GK, which is distinct from sulphonylureas (SUs).

[Effects of berberine on expression of hepatocyte nuclear factor 4alpha and glucokinase activity in mouse primary hepatocytes].

OBJECTIVE: To observe the expression of hepatocyte nuclear factor 4alpha (HNF4alpha) and the activity of key enzyme glucokinase (GK) in glucose metabolism, and further to investigate the possible mechanism of berberine in treating type 2 diabetes. METHOD: Mouse primary hepatocytes were isolated by an improved single two-step perfusion method. The murine hepatocytes were cultured and incubated with berberine (0, 1, 3, 10, 30, 100 micromol x L(-1)) and 1 mmol x L(-1) metformin for 24 h respectively. The mRNA expression of HNF4alpha were quantified by RT-PCR and the protein expression of HNF4alpha were quantified by Western-blot. And the activity of GK were detected with enzyme kinetics method. RESULT: As compared with the negative control group, at a certain concentration range, the expression of HNF4alpha mRNA and protein and the activity of GK were promoted by berberine. Both of them reached the top at the concentration of 30 micromol x L(-1) (P<0.01). But the metformin made no difference with the negative control group on the expression of HNF4alpha and the activity of GK. CONCLUSION: It is suggested that the effects of berberine on improving glucose metabolism can be mechanically associated with its up-regulating the HNF4a expression and inducing the activity of hepatic glucokinase.