Immunological changes among workers occupationally exposed to styrene

The functional status of the immune system was investigated in a group of 71 workers exposed to styrene and in 65 control subjects, recruited according to the same selection criteria and comparable as to sex, age, and confounding variables. Air and biological monitoring were used to characterize styrene exposure (median of the main urinary metabolites in the next-morning spot samples: 106 mg/g creatinine). Phenotypic analysis of peripheral blood lymphocytes (PBL) by automated flow cytometry revealed a reduced proportion of T lymphocyte subsets (CD3⁺, CD4⁺ and CD4⁺45⁺), with no changes in CD8⁺, and a higher proportion of B lymphocytes (CD19⁺) among styrene-exposed workers. The exposed workers showed a higher proportion of activation markers, namely DR and interleukin-2 receptors (CD25). Immunoglobulin subclasses were comparable in the two groups. An increased prevalence of abnormally low values was apparent for CD2⁺, CD3⁺, CD4⁺, CD4⁺45⁺ and CD11b subsets among workers exposed to styrene, whereas CD19⁺, DR⁺ and CD25⁺ showed an increased prevalence of abnormally high values. Natural killer-related phenotypes (CD56⁺, CD56+16⁺, and CD56⁺16^–) were more expressed among styrene workers, with average increase of 30%. However, the frequency distribution of the lytic activity of natural killer cells against K-562 target cells was shifted towards lower values in the exposed workers as compared to control subjects. Dose-response relationships between indices of internal dose and prevalence of abnormal values were detectable for T lymphocyte subsets, NK phenotypes, and activation markers. These findings suggest that moderate exposure to styrene is associated with an altered distribution of lymphocyte subsets. The decreased proportion of T lymphocytes, mainly of T helper-inducer cells, could hamper regulatory functions, thus suggesting a negative modulation by styrene exposure. Since a proper balance between immunocycte subsets is important for immunological responses, such changes should be regarded as adverse effects.     

Einfluß des operationstraumas auf die NK-zell-aktivität beim ösophaguskarizinom nach transmediastinaler dissektion vs. transthorakaler en-bloc-resektion

Zusammenfassung Um den Einfluß des chirurgischen Traumas beim Ösophaguskarzinom auf das zelluläre Immunsystem zu erfassen, wurden perioperativ in einer prospektiven Studie die Aktivität der natürlichen Killerzellen sowie die Serumkonzentrationen von Interleukin-2, Interleukin-6 un TNF- bei transmediastinaler Dissektion (n=12) vs. transthorakaler En-bloc-Resektion (n=10) der Speiserörhre im Vergleich zu einer Kontrollgruppe mit thorakoabdominalen chirurgischen Eingriffen bei nicht maligner Grunderkrankung erfaßt. Die Bestimmung der NK-Zell-Aktivität erfolgte präoperativ sowie am 4. und 10. Tag postoperativ durch einen standardisierten Europiumchlorid-release-Assay unter Verwendung von K-562-Targetzellen, die Lymphokine Interleukin-2, Interleukin-6 und TNF- wurden zusätzlich am 1. und 7. Tag postoperativ mit stadardisierten ELISA-Assays bestimmt.In unserem Patientengut sank die NK-Zellaktivität am 4. postoperrativen Tag sowohl in der Kontrollgrupe al auch bei beiden Operations verfahren zur Speiseröhrenresektion signifikant (p<0,05) zum Ausgangswert: in der Kontrollgruppe durchschnittlich um 45%, nach transmediastinaler Speriseröhrendissektion (1-Höhlen-Eingriff) durchschnittlich um 34%, nauch transthorakaler En-bloc-Resektion (2-Höhlen-Eingriff) im Mittel um 63% zum präoperativen Wert. Die transthorakale En-bloc-Resektion der Speiseröhre führte durch das größere chirurgische Trauma zu einer stäkeren Abnahme der zytotoxischen Aktivität der natürlichen Killerzellen. Eine Suppression der immunologischen Tumorabwehr insbesondere in der vulnerablen perioperativen Phase kann damit indirekt das Risiko der Manifestation von hämatogene Metastasen auf dem Boden einer intraoperativen Tumorzelldissemination u. a. bedingt durch Tumormanipulation begünstigen und damit prognostisch relevant werden.

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Influence of surgical trauma on natural killer cell activity in esophageal carcinoma following transmediastinal dissection compareed with transthoracic en bloc resection

In order to assess the impact of surgical trauma involved in the therapy of esophageal carcinoma on the cellular immune system, a perspective study was performed involving perioperative hematological parameters. The activity of natural killer cells and the serum concentrations of interleuin-2, interleukin-6 and TNF- were measured in 12 cases of transmediastinal dissection and 10 cases of transthioracic en bloc esophageal resection and compared to values of a control group of thoracic and abdominal surgical patients with non-malignant maladies. Natural killer cells assume a central role in the non-specific immunological response in tumor patients. Their main function is the destruction of tumor cells via cytotoxic activities amplified by the release of interleukin-2 and TNF-. Natural killer cell activity was measured prior to surgery and on postoperative days 4 and 10 using a standardized europium chloride release assay, utilizing K 562 target cells. Lymphokines interleukin-2, interleukin-6, and THF- were also measured on postoperative days 1 and 7 using standardized ELISA assays. The activity of natural killer cells in our patient group sank significantly (P<0.05) on postoperative day 4 and likewise in the control group and both study groups, activity sank to the original values. In the control groups, natural killer cell activity averaged 45% of preoperative values, in comparison with an average of 63% following transmediastinal esophageal carcinoma resection (one cavity procedure), and transthoracic en bloc resection patients only reached 61% of preoperative values, transmediastinal dissection patients assumed 75%, and 77% was achieved by control group members. Transthoracic en bloc resection of the esophagus led to a more extreme reduction in cytotoxic cellular activity owing to the greater surgical trauma. Suppression of the immunological tumor resistance, especially in the vulnerable perisurgical pahse, can have an indirect negative effect on the manifestation risk of hematogenic metastases owing to intraoperative tumor cell dissemination resulting from tumor manipulation and may thus be prognostically relevant.

     

High-dose naloxone affects task performance in normal subjects

Increasing intravenous doses of naloxone (0.3 mg/kg, 1 mg/kg, and 2 mg/kg) were administered to normal subjects. Naloxone at 2 mg/kg, but not at lower doses, impaired aspects of memory as measured by a verbal learning task which assessed the direct free recall and recognition of presented versus non-presented words of a single category (effortful processing) and the monitoring of the frequency of such presentations (automatic processing). At the same time "working" memory was left unaffected. The results suggest a role for the opioid system in some memory processes in man.     

Depressed natural killer cell activity due to decreased natural killer cell population in a vitamin E-deficient patient with Shwachman syndrome: reversible natural killer cell abnormality by α-tocopherol supplementation

Natural Killer (NK) cell activity was examined in a 16-month-old Japanese boy with Shwachman syndrome associated with severe vitamin E deficiency. As evaluated by ⁵¹Cr-release assay from K562 cells, NK cell activity was constantly decreased. After 8 weeks of oral α-tocopherol (α-Toc) supplementation (100 mg/day), NK cell activity had normalised. When α-Toc supplementation was interrupted for 16 weeks, NK cell activity again decreased. Flow cytometry of peripheral lymphocytes revealed a lowered number of CD16⁺ CD 56⁻ fraction, which has the most potent NK cell activity. Single cell-in-agarose assay, to investigate the binding and cytolytic activity of NK cell at the single cell level, revealed that the number of NK cells which bind to K562 cell was decreased, but that the cytolytic activity of the individual binding cell was relatively unaffected. A second supplementation of α-Toc for 8 weeks successfully restored NK cell activity, the number of cells expressing NK cell markers and the number of K562-binding cells as compared to the age-matched normal range. Conclusion These results indicate that severe vitamin E deficiency caused impaired NK cell activity due to a decrease in the number of CD16⁺ CD56⁻ NK cells and that this abnormality is reversible with α-Toc supple‐mentation. Received: 30 January 1996 and in revised form: 19 November 1996 / Accepted: 22 November 1996     

Can Young People with Autism Refer to Knowledge States? Evidence from Their Understanding of "Know" and "Guess"

A number of studies have reported that most individuals with autism have difficulty in attributing mental states. The primary aim of the present study was to compare the ability of children with autism to refer to knowledge states with that of mainstream school children and children with Down's syndrome. The second aim was to investigate the role of verbal mental age in referring to knowledge states. The third aim was to compare the ease with which the children referred to their own mental state and to that of others. The results suggest that some individuals with autism are able to attribute knowledge to themselves and others but that they need to have higher verbal skills than is necessary in normal individuals. The level of language skill predicted the performance of the individuals with autism, but not that of the children in the other groups. There was no good evidence that referring to one's own mental states was easier than referring to another person's, a finding which supports representational theory rather than the simulationist position.     

论谓项量化、主项质化理论在语言逻辑中的价值与影响

哈米尔顿的谓项量化理论揭示了量化命题中的简单换位规律 ,突破了原有三段论的规则 ,增加了大量新的三段论式。德摩根的主项质化理论给传统的逻辑方阵增添了新的内容 ,八个命题之间存在着紧密的内在联系 ,谓项量化、主项质化命题有着广泛的思维空间和运用价值 ,且语言表达灵活多样。哈米尔顿和德摩根都对联项“是”作了深入研究、赋予新的内涵 ,给逻辑注入了新的活力。     

High-resolution magnetic resonance and volume rendering of the labyrinth

Our aim was to verify the feasibility of volume rendering (VR) of high-resolution magnetic resonance (HR-MR) data sets of the labyrinth. We retrospectively reviewed the HR-MR data sets of 16 consecutive patients with no MR evidence of labyrinthine pathology. High-resolution MR data sets were obtained by means of a 3D T2-weighted FSE sequence with the use of a 3-in. circular surface coil for signal reception, and processed with a high-end workstation. Two reviewers performed separately VR of the labyrinth by selecting the signal intensity interval for attribution of opacity and transparency. Concerning the time taken for definition of the volume of interest, the two observers needed, respectively, 28.9 and 33.1 min (SD ± 8.7–9.5 min), whereas the time taken for VR was respectively, 26 and 33.2 min (SD ± 8.8–8.9 min). Concerning the selection of the signal intensity interval, the two observers had, respectively, 86.4 and 88.7 mean lower threshold (SD ± 34.5–33.5), 488.9 and 495.4 mean upper threshold (SD ± 56.3–53.8). In our experience, we have found VR of HR-MR to offer a reliable and reproducible technique for producing 3D representations of the labyrinth. The VR algorithms use all data within the imaging volume and optimize the dynamic range ascribed to the object being visualized. Received: 9 October 1998; Revised: 14 January 1999; Accepted: 30 June 1999     

Multiple representations of information in the primary auditory cortex of cats. II. Stability and change in early (<32 ms), rapid components of activity after conditioning with a click conditioned stimulus

Activity was recorded from single units of the A(I) cortex of awake animals to identify early (<32 ms) components of the population response to a 70 dB click and establish if they changed after using the click as a CS for conditioning. A 70 dB hiss was used as a discriminative stimulus. Responses to these stimuli were compared before and after a forward order of pairing that produced conditioning and a backward order of pairing that produced weak sensitization (backward conditioning). Averages of discharges in 2 and 4 ms bins distinguished primary (8-12 ms) from secondary (12-16 ms) temporal components of response to the click, and confirmed that the onset of the response was shorter in A(I) (8 ms, mean of 647 units) than in the adjacent, A(II) cortex (16 ms, mean of 95 units). (All times include a 1.6 ms transmission delay in sound arrival.) Primary and secondary components of A(I) responses to click did not change uniformly after changes in behavioral state, and were affected differently by both conditioning and backward conditioning. The percentage of cells with onsets of response to the click at secondary latencies (and to the hiss at tertiary latencies) increased after backward conditioning but not after conditioning, as did the magnitude of activity in response to the click. (The latter had a lesser degree of increase after conditioning.) The primary response to the click did not show these increases. The non-uniform changes suggested that temporal processing of the click was conducted differently in the 8-12 ms post stimulus period than in the 12-16 ms period. Within the total population of cells, it was possible to identify a small subgroup (13%) of highly auditory-responsive units that showed an increased primary response to the click as a CS selectively after conditioning and not after backward conditioning. The secondary component of response in these cells increased after both conditioning and backward conditioning. The percentages of cells responding to the click and hiss at primary latencies did not change significantly after conditioning, even in the subgroup of highly responsive cells. The results characterize differently timed components of rapid responses to acoustic stimuli in the A(I) cortex, disclose significant temporal differences in primary, secondary and tertiary information processing that affect the representations of the transmitted acoustic message across different behavioral states, and find one representation in a small subgroup of cells that supports the hypothesis that cells of the A(I) cortex have a selectively potentiated response to the CS after conditioning.     

兔角膜损伤面积测量的图像处理方法

目的：研究兔角膜前板层切除模型中，定量分析损伤面积的图像处理方法。方法：新西兰兔6只，切除双眼角膜前板层，直径8mm，约1／3角膜厚度。每日滴1％荧光素染色，裂隙灯钴蓝光下拍摄照片，放大16倍，连续7天。将照片用联想Mustek扫描仪以100dpi扫入计算机，Photoshop软件描绘损伤边缘并剪切，保存为jpg文件。在CPAS软件中打开该文件，阈值化后进行人工调整，达到全部阈值化的目的。利用CPAS的计算功能算出该面积的像素数，并转化为实际面积mm^2。对6张损伤1小时角膜照片做面积分析，与实际面积比较。对1～7天的角膜损伤照片任选12张，做3名不同操作人员之间的损伤面积比较。结果：对6张角膜损伤1小时的面积做图像分析，平均值为51．14mm^2，实际损伤面积为50．24mm^2，相差仅为0．2％，两组之间无显著性差异(P=0．12)。对12张角膜损伤照片3名操作人员测量的损伤面积平均值分别为18．26mm^2、19．81mm^2和18．85mm^2，三组之间均无显著性差异(F=0．044，P=0．957)。结论：利用CPAS软件和Photoshop软件进行兔角膜损伤面积的定量分析，方法可靠、准确，但在图像处理过程中须对阈值化进行人工调整。     

谈日语二外教学中实际运用能力的培养

学习外语的第一目的是与人交流，二外亦是如此。特别是当前中国经济快速发展，对日语人才的需求越来越大的环境下，如何提高日语二外学习者的语言实际运用能力成为一个重要课题。结合笔者的实践，本文着重从听、说以及跨文化交际三方面探讨了日语实际运用能力的培养。