Limits of colour vision in dim light

Humans and most vertebrates have duplex retinae with multiple cone types for colour vision in bright light, and one single rod type for achromatic vision in dim light. Instead of comparing signals from multiple spectral types of photoreceptors, such species use one highly sensitive receptor type thus improving the signal‐to‐noise ratio at night. However, the nocturnal hawkmoth Deilephila elpenor, the nocturnal bee Xylocopa tranquebarica and the nocturnal gecko Tarentola chazaliae can discriminate colours at extremely dim light intensities. To be able to do so, they sacrifice spatial and temporal resolution in favour of colour vision. We review what is known about colour vision in dim light, and compare colour vision thresholds with the optical sensitivity of the photoreceptors in selected animal species with lens and compound eyes.     

高血压脑出血患者血浆超敏C反应蛋白及脂联素与apelin的相关性研究

目的探讨高血压脑出血患者血浆超敏C反应蛋白、脂联素和apelin之间的相关性。方法选择在徐州医学院附属医院门诊或神经外科住院的75例原发性高血压病患者，分为高血压组30例，高血压脑出血组45例；对照组为同期该院体检中心健康体健者，共40例。分别采用化学发光法和酶联免疫吸附法测定血浆超敏C反应蛋白、脂联素、apelin含量，并分析三者之间相关性。结果超敏C反应蛋白：高血压组显著高于对照组（P〈0．01），高血压脑出血组显著高于高血压组（P〈0．01）与对照组（P〈0．01）；脂联素：高血压组显著低于对照组（P〈0．01），高血压脑出血组显著低于高血压组（P〈0．01）与对照组（P〈0．01）；apelin：高血压组显著低于对照组（P〈0．01），高血压脑出血组显著低于高血压组（P〈0．01）与对照组（P〈0．01）。结论血浆超敏C反应蛋白、脂联素和apelin水平的变化与原发性高血压病情程度密切相关，可能对观察病情变化以及评估原发性高血压患者的预后具有重要的临床意义。     

Detection of hidden visual loss in multiple sclerosis

The detection of hidden visual loss is important in establishing the diagnosis of multiple sclerosis, especially in patients who have neurologic symptoms of the disease. Both visual evoked potentials and contrast sensitivity have been used for this purpose. We compared the sensitivities of pattern-reversal visual evoked potentials and contrast sensitivity, measured with the Vistech VCTS 6500 chart, in detecting hidden visual loss in 18 patients with multiple sclerosis whose visual acuity was correctable to 20/20 (6/6) or better in the examined eye. Thirteen patients had delayed visual evoked potential latencies. An additional four patients had reduced P100 amplitudes without prolonged latencies. Nine patients had abnormal contrast sensitivity. The visual evoked potential was more sensitive than contrast sensitivity at detecting hidden visual loss in patients with multiple sclerosis (p < 0.01).Abbreviations MS multiple sclerosis - ON optic neuritis on leave from the Department of Ophthalmology, West Virginia University Health Sciences Center, Morgantown, WVa, USA     

Sensitivity of the Montgomery Asberg Depression Rating Scale to response and its consequences for the assessment of efficacy

An increasing body of evidence is available suggesting that the Hamilton Depression Rating Scale (HAMD) is not a sensitive measure of treatment effect. In this investigation, we explore the sensitivity of the individual items of the Montgomery Asberg Depression Rating Scale (MADRS) and compare the consequences of selecting a different scale as primary endpoint in the analysis of efficacy. A graphical approach is proposed for the evaluation of the sensitivity of individual items to response, using data from randomised, placebo-controlled clinical trials in which HAMD and MADRS were measured concurrently. Subsequently, we illustrate the impact of differences in the sensitivity of the primary endpoint for the detection of statistical significance in treatment effect. In contrast to the HAMD, our item-by-item analysis of the MADRS reveals that all individual items are sensitive to response, irrespective of treatment type. However, some HAMD subscales still outperform MADRS in the detection of treatment effect. The selection of these subscales as primary endpoints in clinical trials could save over 1/3 in patients compared to the full HAMD whilst keeping the same statistical power.     

Deficits in peroneal latency and electromechanical delay in patients with functional ankle instability

The purpose of this study was to compare alterations in peroneal latency and electromechanical delay (EMD) following an inversion perturbation during walking in patients with functional ankle instability (FAI) and with a matched control group. Peroneal latency and EMD were measured from 21 patients with unilateral FAI and 21 controls. Latencies were collected during a random inversion perturbation while walking. EMD measures were collected during stance using a percutaneous stimulus. Two‐way ANOVAs were used to detect differences between leg (affected, unaffected) and group (FAI, Control). Functionally unstable ankles displayed delayed peroneus longus (PL) latencies and EMD when compared to the unaffected leg and a matched control group. Peroneal latency and EMD deficits could contribute to recurrence of ankle injury in FAI subjects. How these deficits are associated with the chronic symptoms associated with FAI remains unclear, but gamma activation and subsequent muscle spindle sensitivity likely play a role. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1541–1546, 2009     

Improved sensitivity in caries clinical trials by selection on the basis of baseline caries experience

As caries prevalence in some countries declines, and panel sizes for discriminating anti-caries clinical trials inevitably increase, the need for participant pre-selection grows to avoid escalating cost and manpower problems. Hence, retrospective analyses of data were undertaken, from a 3-yr double-blind caries clinical trial where a linear fluoride dose-response had been obtained. As a result, it was demonstrated that the eruption status of permanent second molars, in 3005 participants aged 11-12 yr at outset, when coupled with their baseline clinical DMFT values, provided a sound basis for panellist size prediction without loss of sensitivity. Thus, had only those subjects with DMFT greater than 4, with at least three of their permanent second molars erupted been selected following clinical baseline examination, the same sensitivity would have been achieved with 52% fewer subjects. Furthermore, using these criteria, selection can be made on site, in real time, and a child informed whether its immediate participation in a trial is possible.     

Electroretinographic off-response in congenital red-green color deficiency and its genetic carrier

The spectral sensitivity of the rapid off-response in the electroretinogram is found to be abnormal in all protans and deutans so far tested, and in some of their genetic carriers. The rapid off-response is an objective means of assessing the x-linked recessive color deficiencies and their carrier state.     

A review of the active agents available for treatment of dentinal hypersensitivity

Abstract Currently available for treatment of dentinal hypersensitivity are a number of active agents with various degrees of effectiveness. Some of these agents are suitable only for professional application while others can be used by individuals personally in settings outside the dental office. Mechanisms by which these active agents might modify dentin to decrease sensitivity are explored in this review. Published data on the efficacy of various agents, much of it conflicting, is critically examined. Many clinical investigations report a large placebo effect. No single agent has yet been shown to provide all of the desirable qualities of an ideal desensitizer.     

Plasma esterase activity in patients with aspirin-sensitive asthma or urticaria

Summary Plasma aspirin esterase activity and cholinesterase activity were reduced in patients with aspirin sensitive asthma and aspirin sensitive urticaria compared to asthmatic and dermatological controls. Phenylacetate (non specific) esterase activities, were however unaltered in these patients.The reason for the lower activity is uncertain but it does not appear to be due to genetically determined lower cholinesterase or due to the avoidance of aspirin by sensitive patients.A low aspirin esterase activity may be a contributory factor in precipitating these aspirin sensitive reactions.     

Sensitivity of LR115 detector in diffusion chamber to Rn in the presence of Rn

Determination has been made of the sensitivity of LR115 type 2-track detectors (in units of m) to ²²²Rn, measured in the presence of ²²⁰Rn. Measurements have been made by means of a widely used diffusion chamber while Monte Carlo simulations have also been conducted. The experimentally derived sensitivities for ²²²Rn and ²²⁰Rn were found to be 0.470±0.022 and 0.486±0.042 m, respectively. For Monte Carlo simulations, the sensitivities to ²²²Rn gas were found to range from 0.618×10^–2 m (assuming that all ²¹⁸Po progeny decay before deposition onto the internal walls of the diffusion chamber) to 0.405×10^–2 m (assuming that all ²¹⁸Po progeny are deposited on the internal walls of the same containment vessel before decaying). The sensitivity to ²²⁰Rn gas of 0.465×10^–2 m found from Monte Carlo simulations agrees to within uncertainty with experimental findings. The experimentally derived sensitivity value for ²²²Rn indicates that 30% of the ²¹⁸Po progeny decay before deposition onto the internal walls of the diffusion chamber.