Collagen Tubular Airway-on-Chip for Extended Epithelial Culture and Investigation of Ventilation Dynamics.

The lower respiratory tract is a hierarchical network of compliant tubular structures that are made from extracellular matrix proteins with a wall lined by an epithelium. While microfluidic airway-on-a-chip models incorporate the effects of shear and stretch on the epithelium, week-long air-liquid-interface culture at physiological shear stresses, the circular cross-section, and compliance of native airway walls have yet to be recapitulated. To overcome these limitations, a collagen tube-based airway model is presented. The lumen is lined with a confluent epithelium during two-week continuous perfusion with warm, humid air while presenting culture medium from the outside and compensating for evaporation. The model recapitulates human small airways in extracellular matrix composition and mechanical microenvironment, allowing for the first time dynamic studies of elastocapillary phenomena associated with regular breathing and mechanical ventilation, as well as their impacts on the epithelium. A case study reveales increasing damage to the epithelium during repetitive collapse and reopening cycles as opposed to overdistension, suggesting expiratory flow resistance to reduce atelectasis. The model is expected to promote systematic comparisons between different clinically used ventilation strategies and, more broadly, to enhance human organ-on-a-chip platforms for a variety of tubular tissues.

Preparation of copper nanoparticles fluorescent probes and detection of hydrogen peroxide and glucose.

Fluorescent copper nanoparticles (CuNPs) was synthesized by one-step chemical reduction method using ascorbic acid (AA) and copper sulfate (CuSO4⋅5H2O) as raw materials, which had good water solubility and fluorescence properties. A green, simple and safe CuNPs@Fe2+ fluorescence probe was developed for the detection of hydrogen peroxide and glucose using Fe2+ as a bridge. The prepared CuNPs could obtain the maximum fluorescence emission wavelength at 440 nm when the excitation wavelength was 360 nm. The average particle size of CuNPs was 10 nm, which had good photobleach resistance, stability and salt tolerance. The fluorescence intensity was quenched due to electron transfer (ET) process when hydrogen peroxide was added to CuNPs@Fe2+ system. This result was mainly because Fenton reaction occured between hydrogen peroxide and Fe2+, producing hydroxyl free radicals (OH) and Fe3+. Since glucose could be catalyzed by specific glucose oxidase (GOX) to produce H2O2 and corresponding oxidation products, the quantitative analysis of glucose was realized when glucose oxidase was introduced into the CuNPs@Fe2+ sensor system. Therefore, a novel CuNPs@Fe2+ fluorescent probe sensor study was constructed to further achieve quantitative detection of H2O2 and glucose. Under the optimized experimental conditions, the linear ranges for H2O2 and glucose were 28.219-171.562 µM and 1.237-75.771 µM, respectively. And the detection limits for H2O2 and glucose were 7.169 µM and 0.540 µM, respectively. In addition, the mechanism of fluorescence probe quenching caused by the interaction between H2O2 and CuNPs@Fe2+ was also discussed. The proposed sensing system had been applied successfully to the detection of glucose in human serum samples.

One-Step Formation of Protein-Based Tubular Structures for Functional Devices and Tissues.

Tubular biological structures consisting of extracellular matrix (ECM) proteins and cells are basic functional units of all organs in animals and humans. ECM protein solutions at low concentrations (5-10 milligrams per milliliter) are abundantly used in 3D cell culture. However, their poor "printability" and minute-long gelation time have made the direct extrusion of tubular structures in bioprinting applications challenging. Here, this limitation is overcome and the continuous, template-free conversion of low-concentration collagen, elastin, and fibrinogen solutions into tubular structures of tailored size and radial, circumferential and axial organization is demonstrated. The approach is enabled by a microfabricated printhead for the consistent circumferential distribution of ECM protein solutions and lends itself to scalable manufacture. The attached confinement accommodates minute-long residence times for pH, temperature, light, ionic and enzymatic gelation. Chip hosted ECM tubular structures are amenable to perfusion with aqueous solutions and air, and cyclic stretching. Predictive collapse and reopening in a crossed-tube configuration promote all-ECM valves and pumps. Tissue level function is demonstrated by factors secreted from cells embedded within the tube wall, as well as endothelial or epithelial barriers lining the lumen. The described approaches are anticipated to find applications in ECM-based organ-on-chip and biohybrid structures, hydraulic actuators, and soft machines.

[A survey of the long-term incidence rate of benign prostate hyperplasia after vasectomy].

OBJECTIVE: To study the relationship of the long-term incidence rate of benign prostate hyperplasia (BPH) after vasectomy to age and time after operation. METHOD: Questionnaire survey, physical examination, and ultrasonography were conducted among 850 healthy males, aged 55 - 76 who underwent vasectomy more than 20 years before and 390 healthy males, aged 53 - 75, who had not undergone vasectomy in Yichang, Hubei province, selected by randomized cluster sampling. The data such as international prostate symptom scoring (IPSS), quality of life (QOL) index, maximum urine flow rate (MFR), and average flow rate (AFR), digital rectal examination (DRE), volume of prostate gland (V), and residual urine (R) were analyzed. RESULTS: The general BPH incidence rate of the vasectomy group was 10.8%, significantly lower than that of the control group (40.8%, P < 0.01). The age-specific BPH incidence rates in the vasetomy group were all significantly lower than those of the control group, especially that of the subjects aged over 70 (10.8% vs. 56.5%, P < 0.001). The BPH incidence rate of those who had undergone vasectomy 25 years or over before was 7.8%, significantly lower than that of those who had undergone vasectomy 20 years before (13.2%, P < 0.05), but not significantly difference from that of those who had undergone vasectomy 30 years or over before (5.5%, P > 0.05). The volumes of prostate gland in all age subgroups were significantly smaller in the vasectomy group than in the control group. CONCLUSION: Vasectomy reduces the incidence rate of BPH significantly.

[Expression of survivin protein in prostatic carcinoma tissues and its correlation with apoptosis of cancer cells].

OBJECTIVE: To investigate the expression of survivin protein in the tissues of prostatic carcinoma and its correlation with apoptosis of cancer cells. METHODS: Expression of survivin protein and apoptosis index(AI) were detected by immunohistochemical and terminal deoxynucleotidyl transterase-mediated dUTP biotin nich end labeling(TUNEL) technique in the tissues of 42 cases of prostatic carcinima (PCa) and 10 cases of normal prostate (NP). RESULTS: Survivin prosteins were expressed in 34 of the 42 (80.59%) cases of PCa. The positive rate of survivin was strongly associated with pathological grades, clinical stages and lymphmetastasis in PCa(P < 0.05). In contrast, NP did not express survivin. Survivin protein expression was negatively correlated with AI in PCa(r = -0.679, P < 0.001). CONCLUSIONS: Apoptosis inhibition by survivin may participate in the onset and progression of PCa, and the detection of survivin protein and AI in PCa may help to evaluate the degree of cell differentiation, decide therapeutic strategies and estimate prognosis.

[Experimental study of vasoligation in the treatment and prevention of benign prostatic hyperplasia].

OBJECTIVES: To investigate the possibility and efficacy of vasoligation and deferent vein ligation in treating and preventing benign prostatic hyperplasia(BPH). METHODS: 40 male pooches were divided into A, B, C and D groups randomly. Each group has 10 pooches group A and B were made into the model of BPH. Two years later, the pooches in group A and C accepted the operation of vasoligation and deferent vein ligation on both sides. Group B and D only accepted the operation of dissection and relieving its deferent duct. Then continuing to feed the 40 pooches after the operation, they were killed another two years later. After taking out their prostates and calculating their volume and weight, the sections of the prostates were checked by microscope to observe their histology and pathology changes. RESULTS: There were significant differences of weight and volume as well as the changes of histology and pathology between group A and group C (P < 0.01). It was the same with group B and D (hyperplasia changes). CONCLUSIONS: Vasoligation and deferent vein ligation before benign prostatic hyperplasia at pooches grow-up stage can reduce the extent of BPH at old age, and treatment after benign prostatic hyperplasia can make prostatic tissue appear different degrees of atrophy.