Conservation of the chromatophore pigment response

Toxicant sensing technology has evolved to include biological sensors, such as cell‐based biosensors, which rely on viable cells to convey a measurable physiological signal. Chromatophores are a class of pigment cells that have been investigated as cell‐based biosensors. We report the characterization of Oncorhynchus tshawytscha melanophores and describe the melanophore pigment response to neurotransmitters in terms of pigment area occupied. Compared with the previously described model, Betta splendens erythrophores, O. tshawytscha melanophores responded similarly, indicating that pigment responses are biologically conserved between these two species. Additionally, melanophores responded to mercuric chloride and sodium arsenite, similar to B. splendens erythrophores, suggesting that melanophores can be used as detectors for environmental toxicants. This report highlights the potential of O. tshawytscha melanophores to be used as cell‐based biosensors to address environmental toxicity, and warrants a continued investigation to strengthen this technology and its applications.     

体外细胞培养检验“方证对应”关系的方法学研究

目的通过在体外细胞培养中加入中药复方粗提制剂对具有典型的中医证型的肺癌患者的外周血淋巴细胞NK活性的影响，探索能否在体外实验中反映“方证对应”关系。方法以水煎醇沉法制备两种中药复方（益气养阴和健脾化痰）的粗提制剂，取具有典型的中医证型（气阴两虚或脾虚痰湿证型）的肺癌患者的外周血淋巴细胞，将同一个患者的标本分为四个体外实验组，即空白对照组，中药5mg／ml组及10mg／ml组，自细胞介素2（250^u/ml，阳性对照）组。按“辨证论治”原则加入相应的中药复方制剂。体外培养22h或94h，以MTT法检测各组的NK活性。结果无论培养22h或94h，中药组的NK活性与对照组比较皆无显著性差异（P〉0．05），而白细胞介素2（阳性对照）组的NK括性均明显升高（P〈0．05）。结论两种中药复方制剂都未能在体外反应出“方证对应”的效果，说明中药粗提制剂直接用于体外细胞培养，其结果的可靠性差。     

Transmitter Release Associated with Long-term Synaptic Depression in Rat Corticostriatal Slices

Using a corticostriatal slice preparation, we have recently shown that tetanic stimulation of the corticostriatal pathway produces long-term depression (LTD) of striatal excitatory synaptic transmission. In the present study we have analysed the relationship between LTD and the striatal release of different endogenous transmitters. Samples of perfusate were collected via a small cannula placed just above the surface of the striatal slice close to the recording electrode, and were analysed by HPLC. The high-frequency stimulation (100 Hz, three trains, 3 s duration, 20 s intervals) used to induce LTD caused a significant but transient increase in the release of both excitatory (aspartate and glutamate) and inhibitory (glycine and GABA) amino acid transmitters. Tetanic stimulation also produced a significant, but transient increase in the release of endogenous dopamine. We conclude that the tetanic stimulation of the corticostriatal pathway is able to induce a large but transient release of excitatory amino acids and of dopamine, whose participation in the induction of striatal LTD has been demonstrated previously. Moreover, the maintenance of this form of synaptic plasticity does not seem to require a sustained change in transmitter release.     

Validity of a hinged constant force probe and a similar, immobilised probe in untreated periodontal disease

The validity of a hinged constant force probe (0.25 N) was compared with that of a similar but immobilised instrument, using the same interchangeable tip for both (0.64 mm diameter; 2 mm divisions). 60 sites were measured on teeth which were extracted subsequently, in patients with untreated periodontal disease, and the connective tissue attachment level was used as validity criterion. The clinical measurements of both probes correlated well with each other, but they differed significantly from the post-extraction connective tissue attachment level measurements, indicating a point 1.2 mm coronally to this, on average. A companion investigation of intra-operator probing depth reproducibility with the 2 probes, was undertaken in 14 patients, at 2 visits separated by 1 week in each case. All patients had untreated periodontal disease. A difference between probes was found at the first visit, but not at the second; the immobilised probe showed a difference between visits, reducing mean probing depth slightly at the second; when the immobilised probe was used first, there was a difference between probes. Further analysis of the results indicated that there was greatest agreement between probes when the constant force probe had been used before the immobilised probe at the second visit. The results suggested that these probes indicated a point above the connective tissue attachment level, related to pocket morphology, and that there was a moderate learning effect due to operator use of the constant force probe, which modified use of the immobilised probe.     

Remodeling Adult Nursing

This article describes a nursing education experience in which a critical thinking approach was planned and implemented. Background discussion on critical thinking concepts and related research provides a foundation for presentation of the Mackie teaching model. The model uses a community-based, family-centered scenario as the basis for developing problemfocused nursing intervention skills from a holistic viewpoint. Role expectations of students and faculty are outlined, and related implementation difficulties, together with their resolution strategies, are described. Evaluation methods and outcomes are reviewed in the conclusion.     

以问题为中心的病案教学法在临床核医学中的实践

目的 设计以问题为中心的病案小组讨论教学法，在临床核医学核素治疗见习的教学实践中进行验证和评价。方法 总结近几年在临床核医学见习带教中的问题与缺陷；以病案引入问题，教师引导，进行小组讨论；评价教学效果。结果 临床核医学及其教学具有不同于其它临床学科的鲜明特点和规律；经改革的教案，收到学生和教师的良好反馈。结论 以问题为中心的病案小组讨论教学法，切合临床核医学见习实际，有效可行。     

Basic sciences in problem-based learning and conventional curricula: students' attitudes

The purpose of this study was to compare the attitudes toward basic sciences of students in a preclinical problem-based curriculum and a conventional lecture-based curriculum at the end of their second year of medical school. The results showed that the PBL class had more positive attitudes toward basic sciences than students in the conventional class. These results may reflect a learning environment where students meet many scientist role models as teachers and where basic science is learnt in the context of clinical problems.     

Brain dysfunction in social drinkers

Thirty-four social drinkers who had referred themselves to the Regional Brain Damage Unit for assessment of the effects of drinking alcohol were compared with 42 volunteer control subjects of equivalent age but with low alcohol intake, using two 'learning' tests — the Rey Auditory Verbal Learning Test (RAVLT) and the Austin Button Maze. The Maze Test gave no evidence of disorder, but the two groups were significantly different on the RAVLT. No abnormalities in standard cognitive tests were apparent. These results suggest that a deficit in learning ability may be an early feature of the brain dysfunction associated with excessive alcohol consumption.     

A questionnaire examining learning in general practice

Vocational training is a key element of professional development in general practice. Learner-centred approaches to teaching bring a need for greater understanding of the individual learning styles and preferences of trainees. This paper reports the findings of a pilot study undertaken to determine factors that may influence learning among general practice trainees. A questionnaire survey of 261 trainees in six regions in the UK was carried out to explore attitudes to a series of themes identified in semi-structured interviews with trainees at the end of their training. Six distinct subscales were identified using principal components analysis. These are named 'Learning from Patients', 'Openness to Criticism', 'Negative Attitudes', 'Desire for Clear Guidelines', 'Peer Support', and 'Academic Approach'. Males scored significantly higher on 'Academic Approach' (   P < 0.05  ). Each of the subscales reflects themes that permeate the atmosphere of general pratice training. Further work is required to establish relationships between the subscales and the outcomes of learning and to explore the implications for continuing professional development. The questionnaire is an instrument that may prove useful in the future investigation of learning in general practice.