Differences in acquired knowledge and attitudes achieved with traditional,computer-supported and virtual laboratory biology laboratory exercises

This paper reports on the contribution to biological knowledge of three different laboratory technologies and also endeavours to discover which technology students prefer the most. To examine differences in knowledge gained and learners’ preferences for different technologies in biology laboratory work, we prepared three variants (triplets) of three laboratory exercises. Each laboratory variant in a triplet was prepared as a classical laboratory work, a computer-supported laboratory and an interactive virtual simulation. A group of 670 learners at a school for all genders, aged between 11 and 15 (6th to 9th grade) of lower secondary Slovenia schools performed three well-known and easy to perform laboratory exercises that are included in their curriculum (‘Gas Exchange’, ‘Activity of Yeast’ and ‘Heart Rate’) as a traditional, computer-supported laboratory and computer simulation. The data indicated that there were no statistical differences pertaining to students’ knowledge gain between these laboratory technologies with regard to grade, gender or school score. In this study, students preferred a computer-supported laboratory mostly followed by a classic laboratory with a computer simulation in last place, regardless of students’ grade, gender or academic scores.     

Serum-free media for cultures of primitive and mature hematopoietic cells

The in vitro culture of human hematopoietic cells has many research and therapeutic applications. Traditionally, human hematopoietic cultures have been conducted using serum-containing media. The disadvantages inherent in the use of serum could be eliminated by the use of serum-free media. In this review, we summarize and discuss the current status of serum-free media for both mature and immature human hematopoietic cells. The mature hematopoietic cells discussed are of lymphoid (e.g., lymphokine activated killer cells and tumor infiltrating lymphocytes) and myeloid origin (e.g., monocytes/macrophages). The cultures of immature hematopoietic cells discussed are clonogenic and long-term cultures. In addition, we briefly review the types of human hematopoietic cells, their clinical applications, and the basic strategies and components used to formulate serum-free media, Finally, we outline future requirements and directions in the development of serum-free media for primitive hematopoietic cells.     

Pollen capture media: a comparative study

Research laboratories, part of international aerobiological networks are often using different collection media on their exposed tape (or slides). However, their relative pollen capture efficiency has rarely been tested. A single Hirst-trap was used, in Bologna, in February and March 1993, for this experiment. Melinex tapes were divided longitudinally in two equal parts, so that two different media could be tested simultaneously. The tested media were: gelatine/glycerine, hexane/vaseline, silicone/carbon tetrachloride, and paraffin. Each comparisons were repeated on 4 different days. At the time of the sampling, the dominant airborne particles were Cupressaceae andCladosporium. The differences between the different media were non-significant (meanF of different days of 1.720, mean probability of 0.241 (min. of 0.077, max. of 0.356)). The highest probabilities of a significative difference all involved glycerine/gelatine either in comparison with paraffin (0.76), with silicone (0.75), or with vaseline (0.75), while the lowest was for the couple silicone-vaseline (0.59). In general, even if these differences were non-significant, gelatine underestimated spore counts in comparison to silicone, but overestimated them if compared to vaseline or paraffin. However, vaseline looked more efficient then silicone for spore capture. For pollen counts, the same ratios were found, except for the couple silicone-gelatine, which has given similar results. The lowest differences were found withAlternaria andDreschlera, while the highest were found withCladosporium andEpicoccum. The relationship between spore diameter and differences between media was highly significant (τ=?0.786,P=0.027). This was not the case for pollen, withPopulus andAlnus giving the highest differences, andBetula andUlmus the lowest (τ=0.048,P=0.873).     

Efficient callus induction and plant regeneration from filaments with anther in lily (Lilium longiflorum Thunb.)

Bulb scale propagation makes it difficult to obtain a large number of bulblets from disease-free stocks in a short time. The establishment of improved micropropagation procedures by in vitro culture is therefore desirable. Easter lily (Lilium longiflorum Thunb.) filaments with and without anther were excised and cultured in vitro with different media and culture conditions. In cultures of filaments with anther, callus developed and led to bulb, shoot, and root formation, whereas in cultures of filaments lacking anther, callus development did not occur. Among the various media tested, the B5 medium combined with darkness and the N6 medium combined with darkness or light, both supplemented with 9% sucrose, proved to be superior. A total of 1260 plants were regenerated from callus, acclimatized under a mist, and transferred to the greenhouse with a 100% success rate. No morphological abnormalities were observed among plants regenerated from filament-derived callus and all plants displayed isozyme banding patterns identical to the original cultivar. Chromosome observations revealed that all callus-regenerated plantlets tested were diploid (2n=24). The results suggest that in vitro culture of filaments with anther can be cultured for mass propagation. Received: 5 February 1997 / Revision received: 12 May 1997 / Accepted: 2 June 1997     

GLP-1 receptor agonists and reduction of cardiometabolic risk: Potential underlying mechanisms

Type 2 diabetes mellitus (T2DM) is a metabolic condition with an elevated impact on cardiovascular (CV) risk. The innovative therapeutic approaches for T2DM - incretin-based therapies (IBTs), including glucagon-like peptide 1 (GLP-1) receptor agonists, have become popular and more widely used in recent years. The available scientific data from clinical studies and clinical practice highlights their beyond glucose-lowering effects, which is achieved without any increase in hypoglycaemia. The former effects include reduction in body weight, lipids, blood pressure, inflammatory markers, oxidative stress, endothelial dysfunction, and subclinical atherosclerosis, thus reducing and potentially preventing CV events. In fact, the introduction of IBTs is one of the key moments in the history of diabetes research and treatment. Such therapeutic strategies allow customization of antidiabetic treatment to each patient's need and therefore obtain better metabolic control with reduced CV risk. The aim of the present paper is to provide a comprehensive overview of the effects of GLP-1RA on various cardiometabolic markers and overall CV risk, with particular attention on recent CV outcome studies and potential mechanisms. In particular, the effects of liraglutide on formation and progression of atherosclerotic plaque and mechanisms explaining its cardioprotective effects are highlighted.     

Cholesterol ester hydrolase inhibitors reduce the production of synaptotoxic amyloid-β oligomers

The production of amyloid-β (Aβ) is the key factor driving pathogenesis in Alzheimer's disease (AD). Increasing concentrations of Aβ within the brain cause synapse degeneration and the dementia that is characteristic of AD. Here the factors that affect the release of disease-relevant forms Aβ were studied in a cell model. 7PA2 cells expressing the human amyloid precursor protein released soluble Aβ oligomers that caused synapse damage in cultured neurons. Supernatants from 7PA2 cells treated with the cholesterol synthesis inhibitor squalestatin contained similar concentrations of Aβ₄₂ to control cells but did not cause synapse damage in neuronal cultures. These supernatants contained reduced concentrations of Aβ₄₂ oligomers and increased concentrations of Aβ₄₂ monomers. Treatment of 7PA2 cells with platelet-activating factor (PAF) antagonists had similar effects; it reduced concentrations of Aβ₄₂ oligomers and increased concentrations of Aβ₄₂ monomers in cell supernatants. PAF activated cholesterol ester hydrolases (CEH), enzymes that released cholesterol from stores of cholesterol esters. Inhibition of CEH also reduced concentrations of Aβ₄₂ oligomers and increased concentrations of Aβ₄₂ monomers in cell supernatants. The Aβ monomers produced by treated cells protected neurons against Aβ oligomer-induced synapse damage. These studies indicate that pharmacological manipulation of cells can alter the ratio of Aβ monomer:oligomer released and consequently their effects on synapses.     

光通过散射介质聚焦的空间位相逐个单元调节方法

本研究在分析现有散射介质聚焦方法的基础上,提出一种利用单元裂解进行波前位相调制,将经过强散射介质的散射光聚焦的快速收敛方法.文中详细地描述了这一新方法的原理,并同现有逐个单元调节方法进行运行对比.单元裂解方法的物理本质,即为实现空间光调制器的调制各单元光波之间同位相干涉.本方法具有更高的信噪比,并且聚焦收敛的速度快.这一新方法为进一步开展生物成像的光学理论研究提供了新思路.     

鼓室内注射地塞米松联合盐酸氨溴索对分泌性中耳炎患者听力水平及免疫功能的影响

目的:探讨鼓室内注射地塞米松联合盐酸氨溴索对分泌性中耳炎(SOM)患者听力水平及免疫功能的影响。方法:选取2017年5月-2017年11月期间我院收治的SOM患者240例为研究对象。根据随机数字表法将患者分为对照组(n=120)与研究组(n=120),对照组给予鼓室内注入地塞米松治疗,研究组在此基础上联合盐酸氨溴索治疗。比较两组患者临床疗效,比较两组患者治疗前后0.5KHz、1.0KHz、2.0KHz频率下的气导听力水平、鼓室压及CD4+、CD8+、CD4+/CD8+水平,同时观察两组不良反应发生情况。结果:治疗后研究组患者总有效率为86.67%(104/120),高于对照组的70.83%(85/120)(P0.05)。两组患者治疗后0.5KHz、1.0KHz、2.0KHz的气导听力水平以及鼓室压均较治疗前升高,且研究组高于对照组(P0.05)。两组患者治疗后CD4+、CD4+/CD8+均较治疗前升高,且研究组高于对照组(P0.05);两组患者治疗后CD8+较治疗前降低(P0.05),但研究组与对照组比较无差异(P0.05)。两组患者在治疗期间均未发生严重的不良反应。结论:地塞米松联合盐酸氨溴索治疗SOM患者疗效确切,对患者的免疫功能及听力水平均有一定的改善作用,安全性好,具有一定的临床应用价值。