氧分压在体监测仪的研制

作者报道一种稳定性较高的氧分压在体监测，为医学研究、临床诊断提供一种新的可靠的测试方法及设备，具有较大的应用价值。     

How accurate are TheraMon® microsensors at measuring intraoral wear-time? Recorded vs. actual wear times in five volunteers

Background: The TheraMon® microsensor is the most recent device developed to measure the wear-time of removable appliances. The accuracy has not been validated intraorally.

Objectives: To determine 1) if the TheraMon® microsensor accurately records time when fixed intraorally, and 2) the effect of the intraoral location on the recorded time.

Methods: A prospective pilot study, using a convenience sample, was carried out in a UK hospital orthodontic department. Five non-patient volunteers wore microsensors positioned palatal to an upper molar, and buccal to a lower molar for 7 days. Differences between actual amount of wear and the wear recorded by each device were calculated. Differences between sites were also examined.

Results: The mean daily wear-time recorded by the upper and lower microsensors combined was 23 hours (95% CI 22.6–23.4), which is a mean under-recording of 4% (CI 2.5–5.8%). The maximum daily under-reporting of wear times was 5.5 hours. Microsensors in the lower buccal sulcus recorded wear-times that were closer to actual wear-times.

Conclusions: Assumptions made by the TheraMon® microsensors software lead to under-reporting of intraoral wear-time, particularly when placed palatally. These discrepancies could be significant in both clinical practice and research. Adjustment of the microsensor software parameters would improve accuracy, irrespective of the intraoral location.     

Molecularly imprinted poly[tetra(o-aminophenyl)porphyrin] as a stable and selective coating for the development of voltammetric sensors

Molecularly Imprinted poly[tetra(o-aminophenyl)porphyrin] is presented as an electrosynthesized coating for the development of selective microsensors. A carbon fiber microelectrode has been modified with this covering by cyclic voltammetry in the potential range from −0.15 to 1.0 V (scan rate 50 mV s⁻¹) obtaining a microsensor able to recognize the template molecule. To carry out this study dopamine was chosen as model to work with, since this molecule presents electroactivity as it can be oxidized on carbon electrodes. The MIP sensor presented a linear response to the dopamine concentration in the range from 10⁻⁶ to 10⁻⁴ M with good repeatability (RSD 6.22%). The selectivity shown by the microsensor was found to be excellent as it was able to differentiate between different catecholamines. A method has been developed for the determination of dopamine in brain tissue samples using the MIP microsensor.     

腰后关节紊乱症的病机和手法治疗生物力学研究

用微型传感器埋入法，测定腰椎后关节在不同姿势下的位移和受力情况，结果表明：其位移程度和方向受关节突形态的影响，脊柱活动时关节内压力集中在小关节的上端和下端，当某段关节失稳时，较邻近的小关节内压力增大８倍左右。对模拟旋转手法测定表明：后关节内压力呈波浪状变化，其下关节突出现向上→前→下→后的全方位移动。作者从生物力学的角度对腰后关节紊乱症的病机和手法治疗原理进行了探讨。     

In vivo monitoring of extracellular glutamate in the brain with a microsensor

Recent discoveries have revealed that glutamatergic neurotransmission in the central nervous system is mediated by a dynamic interplay between neurons and astrocytes. To enhance our understanding of this process, the study of extracellular glutamate is crucial. At present, microdialysis is the most frequently used analytical technique to monitor extracellular glutamate levels directly in the brain. However, the neuronal and physiological origin of the detected glutamate levels is questioned as they do not fulfil the classical release criteria for exocytotic release, such as calcium dependency or response to the sodium channel blocker tetrodotoxine (TTX). It is hypothesized that an analytical technique with a higher spatial and temporal resolution is required. Glutamate microsensors provide a promising analytical solution to meet this requirement. In the present study, we applied a 10 micro m diameter hydrogel-coated glutamate microsensor to monitor extracellular glutamate levels in the striatum of anesthetized rats. To explore the potential of the microsensor, different pharmacological agents were injected in the vicinity of the sensor at an approximate distance of 100 micro m. It was observed that KCl, exogenous glutamate, kainate and the reuptake inhibitor DL-threo-beta-benzyloxyaspartate (DL-TBOA) increased the extracellular glutamate levels significantly. TTX decreased the basal extracellular glutamate levels approximately 90%, which indicates that the microsensor is capable of detecting neuronally derived glutamate. This is one of the first studies in which a microsensor is applied in vivo on a routine base, and it is concluded that microsensor research can contribute significantly to improve our understanding of the physiology of glutamatergic neurotransmission in the brain.     

Comparison of objective wear time between monoblock and twin-block appliances measured by microsensor

ObjectivesTo assess the objective compliance levels in skeletal Class II patients with mandibular retrognathia wearing monoblock and twin-block appliances.Materials and MethodsA prospective clinical study was conducted with 30 patients between 10 and 15 years old who were equally divided into two study groups. Group 1 was treated with monoblock, and group 2 was treated with twin-block appliances. The patients were instructed to wear their appliance for 15 hours per day. Wear times were monitored by a microsensor. (TheraMon; MCTechnology, Hargelsberg, Austria) for an average of six appointments. Patients were also instructed to record their wear times on a chart, and this record was admitted as subjective wear time. Statistical analysis was performed with the data derived from both the patients'' charts and the monitoring records.ResultsThe mean wear time by the patients was 10.67 ± 3.93 hours, which was less than the 15 hours prescribed by the orthodontist, with no difference between the two appliances (P > .05). The regular use rate, which included the days with a wear time of 8 hours or more per day, was 75%. Compliance levels decreased by 35% throughout the six control appointments. Patients declared that their wear time was more than their objective wear time by an average of 3.76 hours.ConclusionsDespite their different designs, there was no significant difference between the monoblock and twin-block appliances in terms of compliance.     

Improving the reproducibility of hydrogel-coated glutamate microsensors by using an automated dipcoater

Hydrogel-coated microsensors based on carbon fiber electrodes (CFEs) are promising tools for in vivo analysis of endogeneous compounds such as glutamate. However, their construction generally depends on manual fabrication, which often results in poor reproducibility. The aim of this study was to improve the reproducibility and performance of glutamate microsensors. CFEs (10 microm diameter, 300-500 microm long) were coated with a cross-linked redox-polymer hydrogel containing l-glutamate oxidase, horseradish peroxidase and ascorbate oxidase. Various parameters that are likely to influence the reproducibility of the glutamate microsensors were studied. It appeared that the most crucial step in determining the microsensor performance is the manual hydrogel-application procedure. To control this procedure an automated dipcoater was constructed, which allowed mechanical application of the hydrogel on the CFE under standardized conditions. Significant improvements in performance were seen when the CFEs were dipcoated for 10 min at 37 degrees C. Further improvements were obtained when the automated hydrogel application was combined with other cross-link methods, such as electrodeposition and electrostatic complexation. A crucial factor in determining the microsensor performance is the hydrogel thickness. Microscopic observations revealed that, despite the use of an automated dipcoater, the layer thickness was not constant. By combining the automated dipcoat technique with amperometry, the layer thickness could be indirectly monitored and controlled, which resulted in significant improvements of the reproducibility of the sensors.     

Effect of red light on the development and quality of mammalian embryos

Purpose

To assess irradiance and total energy dose from different microscopes during the in-vitro embryonic developmental cycle in mouse and pig and to evaluate its effect on embryonic development and quality in pig.

Method

Spectral scalar irradiance (380–1050 nm) was measured by a fiber-optic microsensor in the focal plane of a dissection microscope, an inverted microscope and a time-lapse incubation system. Furthermore, the effect of three different red light levels was tested in the time-lapse system on mouse zygotes for 5 days, and on porcine zona-intact and zona-free parthenogenetically activated (PA) embryos for 6 days.

Results

The time-lapse system used red light centered at 625 nm and with a lower irradiance level as compared to the white light irradiance levels on the dissection and inverted microscopes, which included more energetic radiation <550 nm. Even after 1000 times higher total energy dose of red light exposure in the time-lapse system, no significant difference was found neither in blastocyst development of mouse zygotes nor in blastocyst rates and total cell number of blastocysts of porcine PA embryos.

Conclusions

Our results indicate that red light (625 nm, 0.34 W/m²) used in the time-lapse incubation system does not decrease the development and quality of blastocysts in both mouse zygotes and porcine PA embryos (both zona-intact and zona-free).