Peabody运动发育量表及配套运动训练方案在运动发育落后患儿中的应用

目的探讨Peabody运动发育量表（PDMS-2）评估方法对发育落后患儿各运动能区发育水平的判断，评价其配套训练方案在改善这些患儿运动技能中的应用价值。方法选取0～5岁运动发育落后患儿56例进行运动发育水平评估（用PDMS-2量表），结果显示单纯粗大运动发育落后患儿12例，单纯精细运动发育落后患儿5例，整体运动功能发育落后患儿39例，随机将这56例患几分为干预组（26例）与对照组（30例），根据PDMS-2评估结果运用其配套训练方案对干预组进行干预，对照组不给任何干预，6个月后再次对两组患儿各运动能区发育水平进行评估（用PDMS-2）。结果干预前对照组粗大运动商（GMQ）、精细运动商（FMQ）和总运动商（TMQ）与干预组之间差异无显著性（P〉0．05）；干预后评估显示两组患儿运动技能都有所提高，但干预组GMQ、FMQ和TMQ均显著大于对照组（P〈0．05）。结论PDMS-2评估方法对发育落后患儿各运动能区发育水平有很好的评估作用，其配套训练方案对提高这些患儿的运动技能是很有价值的。     

Cell Culture in 3-Dimensional Microfluidic Structure of PDMS (polydimethylsiloxane)

In this paper, a device with 3-dimensional microfluidic structure composed of two stacked layers of PDMS (polydimethylsiloxane) is fabricated for mammalian cell culture. This microdevice is tested with Hepatocarcinoma liver cells (Hep G2 cells). The purpose of this study is to understand to what extent cell culture in a PDMS microdevice is available. The experimental protocols for Hep G2 cell culture in the microdevice, such as sterilization steps, collagen pre-coating, etc. have been investigated and established. The oxygen supply could be achieved thanks to the high gas permeability of the PDMS material without any external oxygen supplying system. The cells could be kept in good condition for several days with the present set-up as far as the culture medium is periodically changed. Morphological observations of the cells have shown that they could successfully attach, spread and grow until they reached the confluence over the microfluidic structure. By measuring the glucose consumption and albumin production, the activity of the cells was monitored, and those values had increased gradually along the term of the culture. Those encouraging results illustrate the good cell response to the microfluidic structure, in other words, the culture environment made of PDMS material. In future work, this culture system will be extended to non-cancerous liver cells like normal hepatocytes or endothelial cells.     

A SU-8/PDMS Hybrid Microfluidic Device with Integrated Optical Fibers for Online Monitoring of Lactate

A microfluidic device with integrated optical fibres was developed for online monitoring of lactate. The device consists of a SU-8 waveguide, microfluidic channels and grooves for the insertion of optic fibres. It was fabricated by one-step photolithography of SU-8 polymer resist. Different channel widths (50–300 μm) were tested in terms of detection sensitivity. A wide range of flow rates were applied to investigate the influence of flow rate on signal fluctuations. The separation between optical fibre sensor and microfluidic channel and the width of fluidic channel have been optimized to maximize the detection sensitivity. It was revealed that 250 μm of channel width is the optimum light path length for a compromise between detection sensitivity and interference of ambient light. The independence of detection signals on flow rates was demonstrated within the range of flow rate (0.5–5 ml/hr) tested. Compared with conventional lactate detection, the device is proved to have high accuracy, relatively low limit of detection (50 mg/L) and reasonably fast response time (100 sec). The fabrication of device is simple and low cost. The present work has provided some fundamental data for further system optimization to meet specific detection requirements.     

Real Time PCR on Disposable PDMS Chip with a Miniaturized Thermal Cycler

This paper presents the design and implementation of a low-cost miniature PCR device consisting of a disposable reactor chip and a miniature thermal cycler. The simple fabrication of the PCR chip by PDMS (Polydimethylsiloxane) does not need micro-machining or photolithography processes. The thermal cycler was built with a thin film heater for heating and a fan for rapid cooling. This device can perform PCR tests in a single well chip or a multiple-well chip. It can run PCR reactions of different volumes to meet specific application requirements. The smallest reaction volume tested in this work is 0.9 μL. In addition, this device fits any standard fluorescence microscope for real time detection, which makes real time PCR affordable for most research labs and clinics with a fluorescence microscope. Real-time PCR of E. coli stx1 has been demonstrated with the device described.     

In vitro skin penetration of fragrances: Trapping the evaporated material can enhance the dermal absorption of volatile chemicals

This study compared the evaporation and skin absorption profiles of four fragrance chemicals in in vitro skin penetration studies performed in conditions of airflows of low velocity with and without trapping of the evaporated volatiles. The presence of a trapping chamber above the skin surface slowed down the evaporation of the chemicals, possibly due to formation of a gaseous stagnant layer of greater thickness than the one existing at the skin surface in the real-life conditions of multidirectional and/or turbulent flows. In addition, the use of a trapping chamber considerably influenced the distribution of the fragrance chemicals in the skin layers and resulted in 2- to 8-fold increase of the doses available for systemic absorption. Such unrealistic overestimation of the percutaneous absorption can significantly impact the risk assessment of topically applied volatile chemicals and can lead to defining unrealistic margins of safety.     

The emerging role of forces in axonal elongation

An understanding of how axons elongate is needed to develop rational strategies to treat neurological diseases and nerve injury. Growth cone-mediated neuronal elongation is currently viewed as occurring through cytoskeletal dynamics involving the polymerization of actin and tubulin subunits at the tip of the axon. However, recent work suggests that axons and growth cones also generate forces (through cytoskeletal dynamics, kinesin, dynein, and myosin), forces induce axonal elongation, and axons lengthen by stretching. This review highlights results from various model systems (Drosophila, Aplysia, Xenopus, chicken, mouse, rat, and PC12 cells), supporting a role for forces, bulk microtubule movements, and intercalated mass addition in the process of axonal elongation. We think that a satisfying answer to the question, “How do axons grow?” will come by integrating the best aspects of biophysics, genetics, and cell biology.     

Determination of morphine and codeine in urine using poly(dimethylsiloxane) microchip electrophoresis with electrochemical detection

In this paper, a poly(dimethylsiloxane) (PDMS) microchip with electrochemical (EC) detection was developed for rapid separation and detection of morphine and codeine. It was found that morphine and codeine were well separated within 140 s in phosphate buffer solution (PBS) (pH 6.6, 40 mM)-beta-cyclodextrin (beta-CD) (20 mM)-acetonitrile (30%, v/v). The detection limit was 0.2 microM for morphine and 1 microM for codeine. The protocol was successfully applied to monitoring the amount of morphine and codeine in human urine. Compared with the conventional methods, the presented method had many advantages such as lower instrument cost, less reagent consumption and shorter analysis time.     

Cyclic loading of fractured cadaveric femurs after elastomer femoroplasty: An in vitro biomechanical study

Background

Elastomer femoroplasty is a novel and experimental approach in the prevention of hip fracture surgery. Previously, we published the results of an in vitro cadaveric experiment in which we showed a significant reduction of fracture displacement in treated femurs. The aim of the present study was to establish the failure loads and inter‐fragmentary movement of fractured, elastomer femoroplasty treated femurs during cyclic loading.

Methods

16 cadaveric femurs were treated with elastomer femoroplasty and fractured in a simulated fall configuration. Each specimen underwent 10 cycles with a preload of 50 N, starting with a peak load of 250 N followed by 10 cycles of 500 N and continued with 500 N increments. The crosshead speed was 2 mm/s. The failure load, the number of completed cycles, and crosshead extensions were recorded.

Findings

The mean failure load was 2709 N (SD 1094). The number of completed cycles until failure was 60 (SD 22). The mean translation during maximum loading was 5.25 mm (SD 0.9). At 1500 N (two times the bodyweight of a 75 kg individual) the extension was 3.16 mm.

Interpretation

Preventive elastomer femoroplasty leads to the stabilization of the proximal femur after fracture. In a single leg stance configuration, cyclic loading with mean failure loads that well exceed the peak loads during normal gait is feasible.     

Feasibility of osteosynthesis of fractured cadaveric hips following preventive elastomer femoroplasty

Background

In vitro cadaveric studies showed that elastomer femoroplasty prevents displacement of fracture parts after proximal hip fracture allowing for conservative treatment. In the event that secondary displacement does occur, the purpose of this present study was to determine the feasibility of performing osteosynthesis of a fractured hip after preventive treatment with elastomer femoroplasty.

Methods

Ten pairs of human cadaveric femurs were fractured in a simulated fall configuration. From each pair, one femur was randomly selected for elastomer femoroplasty prior to fracture generation and the contralateral femur was used as control. Following hip fracture generation, osteosynthesis was performed in all femurs. The operative time per case, technical difficulties during the procedure, and postoperative energy-to-failure load were recorded.

Results

The mean (SD) time to perform osteosynthesis was 20 (6) minutes in the control-group and 19 (5) minutes in the elastomer femoroplasty-group (P = 0.69). During osteosynthesis of the fractured hip in the elastomer femoroplasty-group, no difficulties including the need for additional instruments to remove elastomer from the proximal femur were recorded. Postoperative energy-to-failure load was similar in the control-group and the elastomer femoroplasty-group.

Conclusion

Fixation with routine osteosynthesis of displaced cadaveric hip fractures is not hindered by the presence of previously injected elastomer.