Discontinuities in technological and natural systems caused by exotic species

This discussion focuses on discontinuities in both natural and technological systems caused by the introduction of exotic species into areas which they would not have been able to reach without human assistance or other alterations to native communities. The case histories of both the Asian clam and the zebra mussel are particularly instructive because of their recent introductions and the dramatic impact they have had on both natural and technological systems. Control of these mollusc species in technological systems (e.g. water intake systems) is effective to a degree but requires constant attention and utilization of resources. If control is neglected there could be extremely serious consequences. At present, no inexpensive means exist for controlling their effects, and further geographical distribution in North America is highly probable. The mollusc case histories do not appear to be linear and, in some instances, may not be continuous. Some importations of exotic species were deliberate (such as the gypsy moth, Porthetria dispar), but their escape into natural systems has often been accidental or, a less charitable person might say, careless. A viable strategy for coping with discontinuities is elusive. Discontinuities will, undoubtedly, have a major effect on the possibility of sustainable use of the planet or, to use the currently popular term, sustainable development.     

An evaluation of the micronuclei test using triethylenemelamine,trimethylphosphate, hycanthone and niridazole

To determine the feasibility of the micronuclie procedure for cytogenetic studies, a comparatively weak chromosome breaking agent, trimethylphosphate (TMP) and the potent alkylating agent, triethylenemelamine (TEM) were evaluated. The procedure followed was that of Matter and Schmid with the following modifications: (a) direct flushing of bone marrow with 0.2 ml calf fetal serum, (b) air drying slides for a period of only 1 h, and (c) the use of pH 6.0 phosphate buffer to dilute both the Wright and Giemsa stains.With this technique a dose-response curve was generated for both TMP and TEM, using mice as the experimental animal. With TMP, a doubling over background was found when a concentration of 0.5 g/kg per day for five days was administered. To establish a statistically significant doubling dose over the control, a minimum of five animals must be used woth 2000 polychromatic cells being analyzed per animal.Of the two antischistosomal agents tested, hycanthone yielded an increase of 20-fold in the number of mircronuclei over control at 40 mg/kg administered i.p. for five days, while with niridazole no increase in micronuclei at several concentrations tested both by single and multiple injection was found.The results obtained with these compounds compare favorably woth what has been reported for the standard in vivo metaphase analysis.     

An in situ study of rock bass (Ambloplites rupestris) physiology: effect of season and mercury contamination

Selected physiological and biochemical variables were examined in rock bass, Ambloplites rupestris, which were collected on five different sampling dates from an area of chronic mercury contamination and a reference site on the South River, Virginia.The onset of spawning represented the most significant seasonal influence in the physiological profile of the fish, with elevations in hematocrit, hemoglobin, plasma protein, and plasma glucose. Sex-related differences in plasma calcium, liver glycogen and liver ascorbic acid were also unique to the period. Female rock bass had significantly higher levels of liver glutathione than did males on all but one of the sampling dates, although the cause of this difference is not clear.Rock bass from the mercury contaminated site had an average muscle mercury concentration of 1.37 mg Hg g^–1, and an average liver mercury concentration of 2.86 mg Hg g^–1. These levels were approximately an order of magnitude greater than those found in the tissues of the reference fish which averaged 0.165 and 0.101 mg Hg g^–1 in muscle and liver respectively. In July 1987, mercury concentrations in the liver of both reference and contaminated fish increased significantly, possibly the result of greater uptake of the metal through increased feeding or changes in the mercury level of selected prey items. Rock bass collected from the two sites in July also had significantly different levels of liver glutathione: reference fish exhibited an elevation and contaminated fish a depression. When fish from the two sampling stations received a 96-hr exposure to 150 µg HgCl₂ in the laboratory, both groups exhibited elevated liver mercury and decreased liver glutathione. Mercury levels in the gall bladders of the exposed fish were also elevated, suggesting that glutathione may have been lost through excretion with the metal in the bile.On the whole, physiological differences between the two groups of rock bass were limited, indicating that exposure to the mercury is not having a significant impact on the rock bass from the contaminated area. This is further supported by field examination of the fish and comparison of condition indices from rock bass previously taken from the same two stations.Those factors which significantly altered the physiology of the rock bass were unique to certain times of the year, indicating that the most appropriate sampling approach in future studies is one which examines a number of variables over a range of environmental conditions.     

Visualization, fate, and pathogenicity of antigen-specific CD8+ T cells in the graft-versus-host reaction.

To follow the fate of alloreactive T cell effectors in graft-vs-host disease, Ld-specific CD8+ T cells from C57BL/6 2C TCR-transgenic donors were transplanted into sublethally irradiated (750 cGy) Ld+ or Ld- recipients. In Ld- C57BL/6 or (BALB/c-dm2 x C57BL/6)F1 recipients, naive 2C T cells engrafted and survived long term, but did not acquire effector function. In Ld+ (BALB/c x C57BL/6)F1 recipients, 2C T cells engrafted, expanded, became cytolytic, destroyed host B cells and double-positive thymocytes, and later disappeared. Despite marked damage to lymphoid and hemopoietic cells by 2C T cells, no significant pathology was detected in other organs, and recipients survived. Ld+ (BALB/c x C57BL/6)F1 recipients died when LPS/endotoxin was administered on day 7 after cell transfer, while Ld- (BALB/c-dm2 x C57BL/6)F1 recipients survived. Our findings show that under certain conditions, a CD8+ T cell population recognizing an extremely limited repertoire of Ags can initiate graft-vs-host disease.     

H－ras在颊粘膜正常、良性、癌前及恶性变上皮中的表达：免疫组织化学定量研究

本文通过建立图象分析方法对免疫组织化学反应结果进行定量,检测观察Ｈ－ｒａｓ在口腔颊粘膜上皮在正常（Ｎ）、慢性炎症（ＩＦ）、癌旁上皮（ＥＡＣ）和鳞癌（ＳＣＣ）的变化过程中的表达并进行分析。结果显示Ｈ－ｒａｓ在ＳＣＣ组中,以中等分化的ＳＣＣ无论是Ｈ－ｒａｓ表达的量还是细胞阳性率都较高。此外,组织学观察显示,Ｈ－ｒａｓ在处于分化末期但尚未角化的正常上皮细胞中有较高的表达。本文结果显示了Ｈ－ｒａｓ的过表达与上皮细胞的会化程度密切相关。本研究还显示,所采用的阳性区域透光值、平均总透光值及阳性反应区域与阴性反应区域比值可靠并有相关性。这进一步说明了用免疫组化定量方法检测Ｈ－ｒａｓ癌基因表达的精确和可靠性。     

Effects of aerobic exercise therapy and cognitive behavioural therapy on functioning and quality of life in amyotrophic lateral sclerosis: protocol of the FACTS-2-ALS trial

Background

Neuropathic pain must be correctly diagnosed for optimal treatment. The questionnaire named Neuropathic Pain Symptom Inventory (NPSI) was developed in its original French version to evaluate the different symptoms of neuropathic pain. We hypothesized that the NPSI might also be used to differentiate neuropathic from non-neuropathic pain.

Methods

We translated the NPSI into German using a standard forward-backward translation and administered it in a case-control design to patients with neuropathic (n = 68) and non-neuropathic pain (headache and osteoarthritis, n = 169) to validate it and to analyze its discriminant properties, its sensitivity to change, and to detect neuropathic pain subgroups with distinct profiles.

Results

Using a sum score (the NPSI-G score), we found sensitivity to change (r between 0.37 and 0.5 for pain items of the graded chronic pain scale) and could distinguish between neuropathic and other pain on a group basis, but not for individual patients. Post hoc development of a discriminant score with optimized diagnostic properties to distinguish neuropathic pain from non-neuropathic pain resulted in an instrument with high sensitivity (91%) and acceptable specificity (70%). We detected six different pain profiles in the patient group with neuropathic pain; three profiles were found to be distinct.

Conclusions

The NPSI-G potentially combines the properties of a diagnostic tool and an instrument to identify subtypes of neuropathic pain.