ABSTRACT
Gelatin is a biocompatible biomaterial composed of a variety of amino acids that provides a possibility to regulate the interaction between cationic amino acids and neural cells. Based on our first finding that the neuron viability was improved as the lysine on the gelatin was converted into a guanidine structure, a three-dimensional (3D) gelatin hydrogel composed of gelatin and poly(allylguanidine) (PAG) was prepared to investigate neural cell behaviors. As expected, improved neuron viability, neurite outgrowth, synaptogenesis, and inhibited glial cell growth were simultaneously observed in the gelatin cross-linked with the PAG hydrogel (G-PAG) but not in the gelatin hydrogel cross-linked with poly-d-lysine (PDL) or polyethylenimine (PEI). In addition, in vivo tests also illustrated that G-PAG could provide an environment for neural culture, with improving neuron viability and neurite outgrowth. Several hydrogel characteristics-including the swelling ratio, mechanical strength, and electric property-that theoretically can influence neural cell response showed no significant difference among them. Therefore, the guanidine structure of PAG was proposed to determine the behaviors of neural cells within the gelatin-polycation hydrogels, and we proposed that the neural cell behavior is regulated by a specific gelatin-neuron relationship. The information found in this study provides a concept to design and modify gelatin-based hydrogels for neural tissue engineering applications.
ABSTRACT
BACKGROUND: In vitro three-dimensional (3D) hepatic spheroid culture has shown great promise in toxicity testing because it better mimics the cell-cell and cell-matrix interactions found in in vivo conditions than that of the traditional two-dimensional (2D) culture. Despite embedding HepaRG spheroids with collagen type I (collagen I) extracellular matrix (ECM) revealed a much better differentiation capability, almost all the collagen utilized in in vitro hepatocytes cultures is animal-derived collagen that may limit its use in human toxicity testing. METHOD: Here, a preliminary investigation of HepaRG cells cultured in different dimensionalities and with the addition of ECM was performed. Comparisons of conventional 2D culture with 3D spheroid culture were performed based on their functional or structural differences over 7 days. Rat tail collagen (rtCollagen) I and recombinant human collagen (rhCollagen) I were investigated for their ability in promoting HepaRG spheroid differentiation. RESULTS: An immunofluorescence analysis of the hepatocyte-specific functional protein albumin suggested that HepaRG spheroids demonstrated better hepatic function than spheroids from 2D culture, and the function of HepaRG spheroids improved in a time-dependent manner. The fluorescence intensities per unit area of spheroids formed by 1000 cells on days 7 and 10 were 25.41 and 45.38, respectively, whereas almost undetectable fluorescence was obtained with 2D cells. In addition, the embedding of HepaRG spheroids into rtCollagen and rhCollagen I showed that HepaRG differentiation can be accelerated relative to the differentiation of spheroids grown in suspension, demonstrating the great promise of HepaRG spheroids. CONCLUSIONS: The culture conditions established in this study provide a potentially novel alternative for promoting the differentiation of HepaRG spheroids into mature hepatocytes through a collagen-embedded in vitro liver spheroid model. This culture method is envisioned to provide insights for future drug toxicology.
ABSTRACT
BACKGROUND: Few studies have investigated the difference in bacterial contamination between conventional reused ventilator systems and disposable closed ventilator-suction systems. The aim of this study was to investigate the bacterial contamination rates of the reused and disposable ventilator systems, and the association between system disconnection and bacterial contamination of ventilator systems. METHODS: The enrolled intubated and mechanically ventilated patients used a conventional reused ventilator system and a disposable closed ventilator-suction system, respectively, for a week; specimens were then collected from the ventilator circuit systems to evaluate human and environmental bacterial contamination. The sputum specimens from patients were also analyzed in this study. RESULTS: The detection rate of bacteria in the conventional reused ventilator system was substantially higher than that in the disposable ventilator system. The inspiratory and expiratory limbs of the disposable closed ventilator-suction system had higher bacterial concentrations than the conventional reused ventilator system. The bacterial concentration in the heated humidifier of the reused ventilator system was significantly higher than that in the disposable ventilator system. Positive associations existed among the bacterial concentrations at different locations in the reused and disposable ventilator systems, respectively. The predominant bacteria identified in the reused and disposable ventilator systems included Acinetobacter spp., Bacillus cereus, Elizabethkingia spp., Pseudomonas spp., and Stenotrophomonas (Xan) maltophilia. CONCLUSIONS: Both the reused and disposable ventilator systems had high bacterial contamination rates after one week of use. Disconnection of the ventilator systems should be avoided during system operation to decrease the risks of environmental pollution and human exposure, especially for the disposable ventilator system. TRIAL REGISTRATION: ClinicalTrials.gov PRS / NCT03359148.
Subject(s)
Bacteria , Equipment Contamination , Ventilators, Mechanical/microbiology , Adult , Aged , Aged, 80 and over , Bacteria/isolation & purification , Female , Humans , Male , Middle Aged , Respiration, Artificial/adverse effects , Risk , Young AdultABSTRACT
BACKGROUND: It is unknown whether the bronchodilation and anti-inflammatory effects of inhaled salmeterol and fluticasone (SF) are better than those of traditionally inhaled ipratropium, terbutaline and budesonide (ITB) in mechanically ventilated patients with chronic obstructive pulmonary disease (COPD). METHODS: Nineteen stable COPD patients with respiratory failure were randomly enrolled into two groups. Patients were treated with inhaled SF delivered by a metered-dose inhaler with a spacer or with inhaled nebulized ITB. Respiratory parameters were measured for 7 days and plasma cytokine levels were measured on days 1 and 7. RESULTS: The kinetic curve of the rapid shallow index (RSI) from day 1 to day 7 was significant lower in the SF group than that in the ITB group. There were no significant differences in minute ventilation, intrinsic positive end expiratory pressure, and airway resistance between the ITB and SF groups from day 1 to day 7. There were no differences in plasma interleukin (IL)-6, IL-10, IL- 12, and transforming growth factor-beta1 levels between day 1 and day 7 in the ITB or SF group. CONCLUSIONS: Patients with inhaled SF treatment had a lower RSI. The effects of bronchodilators and anti-inflammation were similar between inhaled SF and ITB in COPD patients with ventilator support.