某市无偿献血者ALT标准改变前后检测结果的对比分析

目的统计无偿献血者丙氨酸转氨酶(ALT)的报废阈值改变前后ALT报废率的改变,评价ALT报废阈值变化的意义。方法初筛采用干化学法,复检采用速率法进行ALT检测,统计ALT的报废阈值变化前后的ALT阳性率的改变。结果 ALT的报废阈值改变前,14493例无偿献血者中ALT阳性435例,阳性率为3.00%。ALT的报废阈值改变后,12477例无偿献血者中ALT阳性243例,阳性率为1.95%。结论 ALT的报废阈值的提高有效的降低了血液报废率,节省了血液资源。     

正常青年人多频稳态听觉诱发电位阈值的测试

目的探讨用ASSR阈值预测听力正常耳听力状况和缩短ASSR测试时间的可行性。方法选取28名听力正常的青年人作为受试者（56耳）,对其进行纯音听阈和ASSR阈值测试,记录500、1000、2000和4000Hz四个频率纯音阈值、ASSR阈值出现时的搜索时间和ASSR阈值,根据ASSR阈值均数推测纯音听阈均值,分析ASSR阈值与其纯音听阈的关系和最大搜索时间对ASSR阈值检出率的影响。结果 ASSR在500、1000、2000和4000Hz四个频率的反应阈值分别是29±8、29±8、28±9和30±10dBHL,各频率反应阈值无明显差异（P〉0.05）,各频率ASSR反应阈值与纯音听阈阈值之差在13～15dB之间,各频率ASSR反应阈值与纯音听阈阈值无明显相关性（P〉0.05）,PTA预测值和PTA实测值相差8dB,四个频率最大搜索时间为6和9min时ASSR阈值检出率无明显差异（P〉0.05）。结论听力正常青年人ASSR反应阈值与纯音听阈阈值相差在15dB之内,但两者相关性较差,不宜直接用ASSR阈值预测听力正常人纯音听阈阈值;对于ICSChartrEP系统来说,将最大搜索时间设置为6min可以既不改变ASSR阈值的检出率又缩短ASSR的测试时间。     

时间信息在话题检测中的应用研究

为了克服话题检测中使用静态阈值的缺点,我们提出了基于时间信息的动态阈值模型.在该模型中,探索了一种比值法来选择与某个特定报道最相似的话题.实验结果表明,动态阈值模型很好地改善了话题检测系统的性能.     

对我国成本效果阈值确定方法的思考

目的:对成本效果阈值现有的主要确定方法进行分析,寻找适合我国的阈值确定方法,为我国成本效果阈值的确定及应用奠定基础。方法:通过文献综述的方法,对目前主要的成本效果阈值确定方法进行回顾分析和归纳总结,在此基础上找出适合我国的成本效果阈值确定方法。结果:社会意愿支付法、阈值寻找者模式、人均GDP法均对我国成本效果阈值的确定有重要的借鉴意义。结论:建议以阈值寻找者模式为主、以人均GDP法(社会意愿支付法)为参考来确定我国的成本效果阈值,在寻找我国的成本效果阈值期间,可暂时先借鉴人均GDP法确定的经济性评价标准。     

从多国视角看成本效果阈值的应用现状

目的通过各国成本效果阈值的横向比较,为我国的成本效果阈值设定提供一定的经验与启示。方法归纳总结药物经济学利用程度较高的国家和地区成本效果阈值及其相关规定的现状。结果各国成本效果阈值都不尽相同,成本效果阈值的设定受很多因素的影响。结论不能简单地借鉴国外经验,必须在充分考虑我国具体情况的基础上设定科学合理的成本效果阈值。     

成本效果阈值确定方法分类研究进展(英文)

成本效果分析在卫生保健领域的决策制定当中所起的作用越来越重要。成本效果阈值是成本效果分析的重要决策标准。本文将对成本效果阈值的定义进行回顾,并对现有的成本效果阈值确定方法进行分类介绍,同时对这些现有方法各自的优缺点进行比较分析。在预算具有相对灵活性,即易于改变(增加)既定预算的情况下,成本效果阈值的确定方法主要包括:从过去的决策当中推测阈值、将特殊卫生保健项目的ICER值作为成本效果阈值或借鉴其他公共领域中生命/健康的价值、社会意愿支付法、借助人均GDP确定成本效果阈值法、以及经验确定法。在难以改变既定预算限制的情况下,即当预算具有相对固定性时,能够用于确定成本效果阈值的方法包括:影子价格法、机会成本法和阈值寻找者模型法。现有的八种方法具有其各自的优缺点和适用条件,本文对这些现有方法进行介绍和比较分析,以期能够为我国的成本效果阈值确定方法的选择提供信息储备和支持。     

传染病的数学模型及其动力学特征研究

目的:探讨几类传染病的传播与流行规律.方法:利用微分方程理论建立传染病的数学模型并对模型进行动力学分析.结果:建立了传染病的几个数学模型,并获得了模型的一些动力学特征.结论:某些传染病存在区分传染病是否会流行的阈值.当有关参数值不超过该阈值时,传染病不会流行.当有关参数值大于该阈值时,传染病会流行.     

抑郁症患者的定量感觉研究

目的研究抑郁症患者定量感觉检查（QST）温度觉阈值的特点以及抗抑郁治疗后对QST的影响。方法选择有主观感觉障碍的31例抑郁症患者和30名正常对照组的感觉阈值,分别用包括反应时间在内的Limits法和不包括反应时间在内Levels法测定四肢的冷觉（CS）、温觉（WS）、热痛觉（HP）、冷痛觉（CP）阈值,并进行比较分析。抑郁症组抗抑郁治疗8周后复查QST,治疗前后比较QST阈值结果。结果两种方法所测CS、WS、HP、CP阈值,正常人四肢差异无统计学意义（P〉0.05）;抑郁症组用Limits法所测定的感觉阈值明显较Levels法的阈值增高。两组比较：抑郁症组Limits法所测阈值较对照组增高（P〈0.05）;而Levels法显示两组的阈值接近于正常对照组（P〉0.05）。抗抑郁治疗后,抑郁症组Limits法增高的阈值明显下降（P〈0.05）。结论抑郁症患者存在QST的异常,抑郁症的感觉障碍可能与中枢反应时间延长有关。     

信息价值分析与成本效果阈值

本文介绍了信息价值分析,明确信息价值分析与成本效果阈值之间的关系,指出在我国医药领域引进信息价值分析的必要性,从而进一步论证确定成本效果阈值的理论与现实意义。本文另阐述了信息价值分析的含义、指标及方法,深入分析并举例说明其与成本效果阈值的关系。信息价值分析可视为对不确定性分析的深化,能够定量计算降低不确定性所带来的期望价值;成本效果阈值对信息价值分析意义重大,其取值对信息价值分析起着决定性作用。引进信息价值分析有助于提高行业整体效率。     

从净收益视角探讨成本-效果阈值的意义

目的:旨在从净收益法视角出发,明确成本-效果阈值在药物经济学中的重要意义。方法:分类介绍净收益法的4种情况,从理论方法层面分析4种情况下成本-效果阈值与净收益法的内在联系。结果:净收益法4种情况中的任何一种都要受到成本-效果阈值的影响。结论:净收益法的4种情况均是成本-效果阈值的函数,成本-效果阈值的取值直接决定净收益计算结果。     

盐阈测定在脑卒中患者个性化饮食指导中的应用研究

目的：研究盐阈测定在脑卒中患者个性化饮食指导中的应用。方法选取2012年10月∽2013年10月本院收治的360例脑卒中患者,根据盐阈将360例患者分为高盐阈组（盐阈≥0.68%）210例,中盐阈组（盐阈=0.45%）100例,低盐阈组（盐阈≤0.23%）50例,并对分组患者分别给予统一低盐低脂饮食和个性化的选择性低盐低脂饮食。结果低盐阈组与中盐阈组患者入院时与出院前的盐阈值比较差异无统计学意义（P〉0.05）。高盐阈组出院前的盐阈值明显低于入院时（P〈0.05）。低盐阈组与中盐阈组患者对两种饮食的满意度比较差异无统计学意义（P〉0.05）。高盐阈组对选择性低盐饮食的满意度明显高于统一低盐饮食（P〈0.05）。合计患者对于选择性低盐饮食的满意度明显高于统一低盐饮食（P〈0.05）。结论根据盐阈测定结果,为脑卒中患者进行个体化的低盐低脂饮食指导,既保证了患者的食欲,补充了营养,又得到了患者的认可,积极配合治疗,值得推广应用。     

Asymptotics for threshold regression under general conditions

The inference of the threshold point in threshold models critically depends on the assumption that the density of the threshold variable at the true threshold point is continuous and bounded away from zero and infinity. However, violation of this assumption may arise in several econometric contexts such as treatment effects evaluation. This paper presents a thorough characterisation of the asymptotic distributions in the least‐squares estimation of such abnormal cases. First, the asymptotic results on the threshold point are different from the conventional case. For example, any convergence rate between zero and infinity is possible; the asymptotic distribution can be discrete, continuous or a mixture of discrete and continuous; the weak limits of the localised objective functions can be non‐homogeneous instead of homogeneous compound Poisson processes. Second, this paper distinguishes threshold regression from structural change models by studying a problem unique in threshold regression. Third, the asymptotic distributions of regular parameters are not affected by estimation of the threshold point irrespective of the density of the threshold variable. Numerical calculations and simulation results confirm the theoretical analysis, and the density of the threshold variable in an application is checked to illustrate the relevance of the study in this paper.     

Changing the sensory threshold of elderly people through low-frequency, high-voltage acupoint electrical stimulation

It is widely known that acupoint of electrotherapy decreases the threshold of pain and release of catecholamine by mechanical and chemical stimulation. However, there have been no studies to find the change in the sensory threshold and time-dependent stimulus generated by acupoint electrical stimulation (AES) on the different body regions. The present study was conducted to examine the differences in sensory threshold between elderly and youthful subjects, as well as the sensory threshold by electrical stimulation in the lower back, shoulder, and knee joint regions in the elderly. The sensory threshold was increased in subjects over age 60 compared with 20 year olds. In relation to age, the sensory threshold was increased in the 60 s, 70 s, and 80 s, respectively, compared with during the 20 s. The sensory threshold was significantly increased in the lower back region compared with the shoulder and knee joint regions. The result of the analysis of the sensory threshold in response to the application of electrical stimulation revealed a time-dependent response, with the sensory threshold little changed. However, the change in the sensory threshold was significantly associated with time, increasing after AES from 10 and 15 min compared with 0 min for all ages. It was most pronounced in both the shoulder and knee joint region. Therefore, these results at least partially suggest that the change in sensory threshold is associated with age, and suggest the need to develop specialized physiotherapy to enable seniors to lead healthy lives.     

Convulsive properties of lindane, lindane metabolites, and the lindane isomer alpha-hexachlorocyclohexane: effects on the convulsive threshold for pentylenetetrazol and the brain content of gamma-aminobutyric acid (GABA) in the mouse.

The threshold for pentylenetetrazol-induced convulsions in the mouse is affected by lindane in two opposite ways. Following the administration of a single dose of lindane, the threshold first decreases and then, after 2 days, increases above the normal level. None of the tested metabolites of lindane altered the convulsive threshold. When lindane elevates the convulsive threshold it also elevates the content of γ-aminobutyric acid (GABA) in the brain. The lindane isomer α-hexachlorocyclohexane elevates both convulsive threshold and the GABA content. The smallest single oral dose of lindane lowering the convulsive threshold for pentylenetetrazol in the mouse, 3 hr after administration, corresponds to a lindane concentration of 56 ppb in whole blood.     

Analysis of high-frequency transcutaneous electrical nerve stimulation-induced sensory threshold from the elderly people for healthy life

It is generally known that transcutaneous electrical nerve stimulation (TENS) decreases the threshold of pain and release of catecholamine by mechanical and chemical stimulation. However, there have been no studies to find the change in the sensory threshold and time-dependent stimulus by TENS on the body regions. The present study was to examine the difference of sensory threshold by electrical stimulation at low back and scapulodorsal and knee joint regions in the elderly people. The sensory threshold was significantly increased in the lower back compared with the shoulder and knee joint regions. The sensory threshold tended to increase in the older age group, increasing particularly in subjects in their 80s. The change of the sensory threshold was significantly associated with a time-dependent manner, increasing after stimulation from 5, 10, and 15 min compared with 0 min for all ages. Furthermore, the sensory threshold in response to the application of TENS revealed a time-dependent response, with the sensory threshold tending to increase with age, in particular, in the lower back region. Therefore, these results at least partially suggest that the change of sensory threshold is associated with age, and that needed of the development of senile specialized physical therapy for healthy life.     

The Tobit model with a non‐zero threshold

Summary The standard Tobit maximum likelihood estimator under zero censoring threshold produces inconsistent parameter estimates, when the constant censoring threshold γ is non‐zero and unknown. Unfortunately, the recording of a zero rather than the actual censoring threshold value is typical of economic data. Non‐trivial minimum purchase prices for most goods, fixed cost for doing business or trading, social customs such as those involving charitable donations, and informal administrative recording practices represent common examples of non‐zero constant censoring threshold where the constant threshold is not readily available to the econometrician. Monte Carlo results show that this bias can be extremely large in practice. A new estimator is proposed to estimate the unknown censoring threshold. It is shown that the estimator is superconsistent and follows an exponential distribution in large samples. Due to the superconsistency, the asymptotic distribution of the maximum likelihood estimator of other parameters is not affected by the estimation uncertainty of the censoring threshold.     

The NICE cost-effectiveness threshold: what it is and what that means

The National Institute for Health and Clinical Excellence (NICE) has been using a cost-effectiveness threshold range between pound20 000 and pound30 000 for over 7 years. What the cost-effectiveness threshold represents, what the appropriate level is for NICE to use, and what the other factors are that NICE should consider have all been the subject of much discussion. In this article, we briefly review these questions, provide a critical assessment of NICE's utilization of the incremental cost-effectiveness ratio (ICER) threshold to inform its guidance, and suggest ways in which NICE's utilization of the ICER threshold could be developed to promote the efficient use of health service resources.We conclude that it is feasible and probably desirable to operate an explicit single threshold rather than the current range; the threshold should be seen as a threshold at which 'other' criteria beyond the ICER itself are taken into account; interventions with a large budgetary impact may need to be subject to a lower threshold as they are likely to displace more than the marginal activities; reimbursement at the threshold transfers the full value of an innovation to the manufacturer.Positive decisions above the threshold on the grounds of innovation reduce population health; the value of the threshold should be reconsidered regularly to ensure that it captures the impact of changes in efficiency and budget over time; the use of equity weights to sustain a positive recommendation when the ICER is above the threshold requires knowledge of the equity characteristics of those patients who bear the opportunity cost. Given the barriers to obtaining this knowledge and knowledge about the characteristics of typical beneficiaries of UK NHS care, caution is warranted before accepting claims from special pleaders; uncertainty in the evidence base should not be used to justify a positive recommendation when the ICER is above the threshold. The development of a programme of disinvestment guidance would enable NICE and the NHS to be more confident that the net health benefit of the Technology Appraisal Programme is positive.     

The effect of p-bromomethamphetamine (V-111), a selective serotoninergic amphetamine, on the convulsive seizure excitability threshold in mice

The effect of p-bromomethamphetamine (V-111), a selective serotoninergic amphetamine analogue, on convulsive seizure excitability threshold was evaluated in male albino mice. It was found to be most effective in subcutaneous doses of 15 mg/kg and intracerebroventricular doses of 25 fig per mouse. In a single dose of 15mg/kg, V-111 elevated the pentylenetetrazol threshold when the latter was applied at 30 min, 1 hr or 3 hr; after this time V-111 decreased the threshold. The effect of V-111 on the pentylenetetrazol threshold was changed by drugs which influence serotoninergic synaptic transmission.

p-Chlorophenylalanine decreased the threshold while 5-hydroxytryptophan, imipramine and the combination of 5-hydroxytryptophan and imipramine increased it. Nialamide caused no change in the threshold. The changes in the convulsive seizure excitability threshold are considered to be due to inhibition of intraneuronal 5-hydroxytryptamine and dopamine uptake and alteration of the brain level of 5-hydroxytryptamine induced by V-111.