Altered gut microbiota is associated with feeding intolerance in preterm infants.

BACKGROUND: Feeding intolerance (FI) is a common complication that may cause great harm to preterm infants. The mechanism of FI remains unclear, but probiotics may help prevent and alleviate its symptoms. We hypothesized that the alteration in gut microbiota may be associated with the development of FI. Our study aimed to investigate the association between gut microbiota and FI in preterm infants. METHODS: Ninety-seven preterm infants were divided into the FI group (N=42) and the feeding tolerance (FT) group (N=55) depending on whether the infants were diagnosed with FI. The fecal samples of each infant were collected on the 7th day after birth. Fecal microbiota was analyzed by 16S rRNA sequencing. Plasma motilin were detected on day-1, 7, 14, and 21. RESULTS: The microbial diversity of the FI group was significantly lower than that of the FT group. The abundance levels of phylum Proteobacteria, class Gammaproteobacteria, genera such as Escherichia/Shigella were higher in the FI group than in the FT group. The abundance levels of phylum Firmicutes, class Negativicutes, and genus Veillonella were higher in the FT group than in the FI group. The motilin levels on days 7 and 14 were negatively correlated with the FI-enriched genera Planomicrobium and Vibrio, respectively. Our study also found gut microbiota was correlated with FI clinical characteristics, including gestational age, birth weight, age of FI diagnosis, age of FI disappearance, and FI duration. CONCLUSIONS: Altered gut microbiota is associated with FI in preterm infants. FI cases typically have lower microbial diversity, a decreased abundance of beneficial bacteria, and an increased abundance of pathogenic bacteria. Gut microbiota is correlated with the clinical characteristics of FI. The decrease in motilin secretion caused by some bacteria may lead to the occurrence of FI.

T-lymphocyte subsets and Th1/Th2 cytokines in convalescent patients with Epstein-Barr virus-associated aplastic anemia.

Objective: The aim of this study was to analyze T-lymphocyte subsets and Th1/Th2 cytokines in convalescent patients with Epstein-Barr virus (EBV)-associated aplastic anemia (AA).Methods: Sixty AA patients were enrolled, who were in remission following immunosuppressive therapy, including 34 EBV-negative cases and 26 EBV-positive cases. Their complete blood count (CBC), T-lymphocyte subsets, Th1/Th2 cytokines were analyzed. The correlation between EBV-DNA and T-lymphocyte subsets was evaluated, as well as the relationship between EBV-DNA and Th1/Th2 cytokines. The presence of EBV-DNA in peripheral blood mononuclear cells (PBMCs) was also assessed in 60 normal controls.Results: EBV-DNA was detected in 26/60 (43.33%) patients and 21/60 (35.00%) controls. EBV-DNA copy number in AA patients was higher than in controls (Z = -2.138, P = 0.033). The percentage of CD3+CD4+ T-lymphocytes and the ratio of CD4+/CD8+ T-lymphocytes in the EBV-negative group were higher than in the EBV-positive group (P = 0.001 and 0.001, respectively). EBV was positively correlated with CD3+CD8+ T-lymphocyte percentages (Pearson R: 0.496, P = 0.009). Moreover, EBV was positively correlated with IL-10 and IFN-γ levels (Pearson R: 0.559, P = 0.002 and Pearson R: 0.621, P = 0.001, respectively).Conclusions: EBV-DNA copy number in AA patients was higher than in normal controls. Both AA and EBV infection may cause changes in the levels of T-lymphocyte subsets. We recommend monitoring the changes in the immune function and EBV infection simultaneously in AA patients, especially following immunosuppressive therapy.

Synergistic Effect of Ultrasound and Polyethylene Glycol on the Mechanism of the Controlled Drug Release from Polylactide Matrices.

In this paper, the synergistic effect of ultrasound and polyethylene glycol (PEG) on the controlled release of a water soluble drug from polylactide (PLA) matrices was studied. When ultrasound was used following the hot melt extrusion (HME) of the PLA/model drug release system, the release of the model drug (Methylene Blue (MB)) from the PLA when immersed in phosphate buffered saline (PBS) was affected by the variation of the parameters of ultrasound. It was found that no more than 2% PLA dissolved during the in-vitro release study, and the release of the MB from the PLA was diffusion controlled and fit well with the Higuchi diffusion model. Polyethylene glycol (PEG), which has high hydrophilicity and rapid dissolution speed, was blended with the PLA during the melt extrusion to enhance the release of the MB. The analysis of the structure and properties of the in-vitro release tablets of PLA/PEG/MB indicated that the ultrasound could improve the dispersion of MB in the PLA/PEG blends and it could also change the structure and properties of the PLA/PEG blends. Due to the dissolution of the PEG in PBS, the release of the MB from the PLA/PEG drug carrier was a combination of diffusion and erosion controlled release. Thus a new mechanism combining of diffusion and erosion models and modified kinetics model was proposed to explain the release behavior.

[Spectroscopic Study on a Direct-Current Driving Plasma Jet in Argon at Atmospheric Pressure].

With a discharge device in a hollow-needle and plate electrode configurations, an atmospheric pressure uniform plasma plume is generated by DC voltage excitation in the ambient air with argon as working gas. The plasma plume is a pulsed discharge despite a direct current voltage is applied through measurements by optical and electrical methods. In order to explain the formation mechanism of the pulse, spatially resolved signals emitted from the plume were detected. It was found that the plasma plume denoted as the luminous layer propagates (a plasma bullet) from the hollow needle to the plate electrode except for the corona discharge in the vicinity of the hollow needle tip. Optical emission spectroscopy is used to investigate the excited electron temperature of the plasma plume as a function of the applied voltage or the spatial distribution of the excited electron temperature. The results show that the excited electron temperature (about 3 eV) increases with increasing applied voltage. Moreover, it increases with the increasing distance along the gas flow under constant voltage.

[Investigation on the Spectral Characteristics of a Plasma Jet in Atmospheric Argon Glow Discharge].

Plasma jet is a kind of important plasma source at atmospheric pressure. In recent years, it becomes an important hot topic in the field of low temperature plasma. In this paper, using a tungsten needle and a tungsten wire mesh, a direct-current excited jet is developed to operate in argon at atmospheric pressure. In the atmospheric pressure argon, the plasma jet can produce a stable plasma plume. By using the method of emission spectroscopy, the parameters of the plasma plume are investigated. The discharge emits dazzling white light from the area between the tungsten needle electrode and the wire mesh electrode. A plasma plume with a flame shape appears outside the tungsten wire mesh electrode. For a constant value of voltage (U = 13.5 kV), the length of the plasma plume increases with the gas flow rate. For a constant value of the gas flow rate(10 L · min⁻¹), the length of the plasma plume increases with the voltage. The voltage is inversely proportional to the current under the constant gas flow rate. In other words, the voltage decreases with the discharge current, which indicates that a glow discharge is formed in the plasma jet. Optical emission spectrum in 300 to 800 nm is collected from the direct-current excited plasma jet. By Boltzmann plot method, the excited electron temperature of the plasma plume is investigated as a function of the applied voltage or the gas flow rate. Results show that the excited electron temperature increases with decreasing applied voltage under the constant gas flow. Moreover, it increases with decreasing the gas flow under the constant voltage. Based on the discharge theory, these experimental phenomena are explained qualitatively. These results are of great importance to the development of atmospheric pressure uniform discharge plasma source and its application in industrial field.

[Investigation of a jet operated in atmospheric pressure argon by optical emission spectroscopy].

A uniform plasma plume was generated in a coaxial dielectric barrier discharge jet through blowing argon into the ambient air at atmospheric pressure. The plasma plume was uniform along the direction of the gas flow. The length of the plasma plume was investigated as a function of the peak voltage, the driving frequency and the gas flow rate. It was found that with increasing the gas flow rate, the plume length increases when the flow rate is lower than 4 L x min(-1), and decreases when it is higher than 4 L x mic(-1). Under constant gas flow rate, the length of the plasma plume increases with the increase in the peak value of the applied voltage and the driving frequency. According to the discharge theory and based on the analysis of the turbulence and the advection, a qualitative explanation was given for the variance of plume length as functions of the experimental parameters. Results also show that there is a discharge pulse for the plasma plume in every positive half cycle, while there is no pulse in negative half cycle. The coaxial dielectric barrier discharge shows two pulses in every positive half cycle and a pulse in every negative half cycle. Analyzing these experimental phenomena mentioned above, a formation mechanism of the plasma plume was proposed. The optical emission spectra were obtained for both the coaxial dielectric barrier discharge and the plasma plume. There was no apparent difference except that some emission lines from reactive species such as OH and N2 were found in the plasma plume. Using the first negative band of, the rational temperature of the plasma plume was measured. Results show that the rational temperature of the plasma plume decreases away from the jet nozzle, and increases with increasing the peak value of the applied voltage.

[Spectroscopic characteristics of DC excited atmospheric pressure glow discharges generated in a needle-plate electrode device and a needle-water electrode one].

Glow discharge characteristics in two discharge devices, i.e. in a needle-plate electrode geometry and a needle-water electrode one were compared by using spectroscopic method. Results show that the different emission regions were found in both discharges generated by the two devices. From the cathode to the anode, there are a cathode glow region, cathode dark glow, a positive column, and an anode glow region. The anode dark region can be clearly discerned in the glow discharge in the needle-plate electrode device, while it almost cannot be found in the needle-water electrode discharge. Comparing the current-voltage characteristics of the two glow discharges, it was found that the voltage across the electrodes decreases with increasing the discharge current in both discharge devices, while the voltage in the needle-water glow discharge is higher than that of the needle-plate one at the same current value. The current-voltage curves have a negative slope and their current densities lie in the range from 10-5 to 10-4 A? cm-2, which indicates that a normal glow discharge mechanism was involved in the two discharges. Comparing the optical spectra scanning from 300nm to 800nm and emitted from the whole normal glow discharge in the two electrode devices, similar spectral lines from the two discharges can be found on the optical emission spectrum, including the second positive system of nitrogen molecules (337.1nm) and the first negative system of nitrogen molecular ions (391.4nm). However, the intensity ratio of spectral lines is different. The intensity ratio (391.4nm to 337.1nm) and vibrational temperature were investigated at different locations. It was found that the intensity ratio of the needle-water electrode discharge is larger than that of the needle-plate electrode discharge at the same location. Furthermore, the vibrational temperature in the needle-water electrode discharge is higher than that of the needle-plate one at the same location.

[Vibrational temperature of plasma plume in atmospheric pressure air].

A tri-electrode discharge device was designed in a dielectric barrier discharge configurations to generate a fairly large volume plasma plume in atmospheric pressure air. The discharge characteristics of the plasma plume were investigated by an optical method. The discharge emission from the plasma plume was collected by a photomultiplier tube. It was found that the number of discharge pulse per cycle of the applied voltage increased with increasing the peak value of the applied voltage. The emission spectra of the plasma plume were collected by a spectrometer. The vibrational temperature was calculated by fitting the experimental data to the theoretical one. Results showed that the vibrational temperature of the plasma plume decreases with increasing the U(p). Spatially resolved measurement of the vibrational temperature was also conducted on the plasma plume with the same method. Results showed that the vibrational temperature increases firstly and then decreases with increasing distance from the nozzle. The vibrational temperature reachs its maximum when the distance is 5.4 mm from the nozzle. These experimental phenomena were analyzed qualitatively based on the discharge theory. These results have important significance for the industrial applications of the plasma plume in atmospheric pressure air.