Ultrasound Microbubble-Facilitated Inner Ear Delivery of Gold Nanoparticles Involves Transient Disruption of the Tight Junction Barrier in the Round Window Membrane

The application of ultrasound microbubbles (USMBs) enhances the permeability of the round window membrane (RWM) and improves drug delivery to the inner ear. In this study, we investigated the efficiency of USMB-aided delivery of chitosan-coated gold nanoparticles (CS-AuNPs) and the mechanism of USMB-mediated enhancement of RMW permeability. We exposed mouse inner ears to USMBs at an intensity of 2 W/cm² and then filled the tympanic bulla with CS-AuNPs or fluorescein isothiocyanate-decorated CS-AuNPs (FITC-CS-AuNPs). The membrane uptake of FITC-CS-AuNPs and their depth of permeation into the three-layer structure of the RWM, with or without prior USMB treatment, were visualized by z-stack confocal laser scanning microscopy. Ultrastructural changes in the RWM due to USMB-mediated cavitation appeared as sunburn-like peeling and various degrees of depression in the RWM surface, with pore-like openings forming in the outer epithelium. This disruption of the outer epithelium was paralleled by a transient reduction in tight junction (TJ)-associated protein levels in the RWM and an enhanced delivery of FITC-CS-AuNPs into the RWM. Without prior USMB exposure, the treatment with CS-AuNPs also caused a noticeable reduction in TJ proteins of the RWM. Our findings indicated that the combined treatment with USMBs and CS-AuNPs represents a promising and efficient drug and gene delivery vehicle for a trans-RWM approach for inner ear therapy. The outer epithelial layer of the RWM plays a decisive role in controlling the transmembrane transport of substances such as CS-AuNPs following the administration of USMBs. Most importantly, the enhanced permeation of AuNPs involved the transient disruption of the TJ-created paracellular barrier in the outer epithelium of the RWM.

[Predictive factors of mortality in extremely preterm infants]

Objective: To investigate the predictive factors of mortality in extremely preterm infants. Methods: The retrospective case-control study was accomplished in the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University. A total of 268 extremely preterm infants seen from January 1, 1999 to December 31, 2015 were divided into survival group (192 cases) and death group (76 cases). The potential predictive factors of mortality were identified by univariate analysis, and then analyzed by multivariate unconditional Logistic regression analysis. The mortality and predictive factors were also compared between two time periods, which were January 1, 1999 to December 31, 2007 (65 cases) and January 1, 2008 to December 31, 2015 (203 cases). Results: The median gestational age (GA) of extremely preterm infants was 27 weeks (23⁺³-27⁺⁶ weeks). The mortality was higher in infants with GA of 25-<26 weeks (OR=2.659, 95% CI: 1.211-5.840) and<25 weeks (OR=10.029, 95% CI: 3.266-30.792) compared to that in infants with GA> 26 weeks. From January 1, 2008 to December 31, 2015, the number of extremely preterm infants was increased significantly compared to the previous 9 years, while the mortality decreased significantly (OR=0.490, 95% CI: 0.272-0.884). Multivariate unconditional Logistic regression analysis showed that GA below 25 weeks (OR=6.033, 95% CI: 1.393-26.133), lower birth weight (OR=0.997, 95% CI: 0.995-1.000), stage Ⅲ necrotizing enterocolitis (NEC) (OR=15.907, 95% CI: 3.613-70.033), grade Ⅰ and Ⅱ intraventricular hemorrhage (IVH) (OR=0.260, 95% CI: 0.117-0.575) and dependence on invasive mechanical ventilation (OR=3.630, 95% CI: 1.111-11.867) were predictive factors of mortality in extremely preterm infants. Conclusions: GA below 25 weeks, lower birth weight, stage Ⅲ NEC and dependence on invasive mechanical ventilation are risk factors of mortality in extremely preterm infants. But grade ⅠandⅡ IVH is protective factor.

Multiplex polymerase chain reaction assay for the detection of minute virus of mice and mouse parvovirus infections in laboratory mice

Mouse parvoviruses are among the most prevalent infectious pathogens in contemporary mouse colonies. To improve the efficiency of routine screening for mouse parvovirus infections, a multiplex polymerase chain reaction (PCR) assay targeting the VP gene was developed. The assay detected minute virus of mice (MVM), mouse parvovirus (MPV) and a mouse housekeeping gene (α-actin) and was able to specifically detect MVM and MPV at levels as low as 50 copies. Co-infection with the two viruses with up to 200-fold differences in viral concentrations can easily be detected. The multiplex PCR assay developed here could be a useful tool for monitoring mouse health and the viral contamination of biological materials.

Rodent models for investigating the dysregulation of immune responses in type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease mediated by T cells that selectively destroy the insulin-producing β cells. Previous reports based on epidemiological and animal studies have demonstrated that both genetic factors and environmental parameters can either promote or attenuate the progression of autoimmunity. In recent decades, several inbred rodent strains that spontaneously develop diabetes have been applied to the investigation of the pathogenesis of T1D. Because the genetic manipulation of mice is well developed (transgenic, knockout, and conditional knockout/transgenic), most studies are performed using the nonobese diabetic (NOD) mouse model. This paper will focus on the use of genetically manipulated NOD mice to explore the pathogenesis of T1D and to develop potential therapeutic approaches.

Use and outcomes of venous thromboembolism prophylaxis after spinal fusion surgery

BACKGROUND

The number of spinal fusion operations in the USA is rapidly rising, but little is known about optimal venous thromboembolism prophylaxis after spinal surgery.

OBJECTIVES

To examine the use of and outcomes associated with venous thromboembolism prophylaxis after spinal fusion surgery in a cohort of 244 US hospitals.

PATIENTS/METHODS

 We identified all patients with a principal procedure code for spinal fusion surgery in hospitals participating in the Premier Perspective database from 2003 to 2005, and searched for receipt of pharmacologic prophylaxis (subcutaneous unfractionated heparin, low molecular weight heparin, or fondaparinux) and/or mechanical prophylaxis (compression devices and elastic stockings) within the first 7 days after surgery. We also searched for discharge diagnosis codes for venous thromboembolism and postoperative hemorrhage during the index hospitalization and within 30 days after surgery.

RESULTS

Among 80,183 spinal fusions performed during the time period, cervical fusions were the most common (49.0%), followed by lumbar fusions (47.8%). Thromboembolism prophylaxis was administered to 60.6% of patients within the first week postoperatively, with the most frequent form being mechanical prophylaxis alone (47.6%). Of the 244 hospitals, 26.2% provided prophylaxis to ≥ 90% of their patients undergoing spinal fusion; however, 33.2% provided prophylaxis to fewer than 50% of their patients. The rate of diagnosed venous thromboembolism within 30 days after surgery was 0.45%, and the rate of postoperative hemorrhage was 1.1%.

CONCLUSIONS

 Substantial variation exists in the use of thromboembolism prophylaxis after spinal fusion surgery in the USA. Nevertheless, overall rates of diagnosed thromboembolism after spinal fusion appear to be low.

Kinetics of adaptive immunity to Haemophilus influenzae type b meningitis in transgenic mice: evidence from diverse expression of double T1/T2 transgenes and Th1/Th2-related cytokines

To investigate the kinetic changes in adaptive immunity during experimental Haemophilus influenzae type b (Hib) meningitis, we established a murine meningitis model based on T1/T2 doubly transgenic mice. These mice carry two transgenes that express two distinct cell-surface markers: a human Thy1 transgene (hThy1) under the control of the murine IFN-gamma promoter, and a murine Thy1.1 transgene (mThy1.1) under the control of the murine IL-4 promoter, designated T1 and T2, respectively. Mice infected with Hib displayed severest symptoms and lowest total splenocyte counts on day 3 after infection. Simultaneously, we examined the significantly low percentage of CD19+ B cells, the relatively high level of CD4+ T cells and significantly high percentage of CD8+ T cells in Hib-infected mice. Furthermore, we observed the early induction of both Th1 and Th2 responses, in terms of the augmentation of Th1 cells (IFN-gamma-producing CD4+ T cells) and Th2 cells (IL-4-producing CD4+ T cells) in Hib-infected mice. On day 7 after infection, the Th1 response gradually declined and the Th2 response rather sustained. Two weeks after infection, both Th1 and Th2 cells were barely detectable. Moreover, we demonstrated using an antigen-specific re-stimulation test to analyze the effector function of lymphocyte subsets that CD8+ T cells contributed to more predominantly production of IFN-gamma than CD4+ T cells did; and CD4+ T cells partly contributed to the secretion of IL-4 from flowcytometry of intracellular cytokine staining. Our results support that these transgenic mice provide an available model to dissect the complex kinetic change of adaptive immunity in bacterial infectious diseases.