批判医学人类学的历史与理论框架

回顾20世纪70年代以来逐步形成,并在现实社会问题研究中越来越彰显重要性的批判医学人类学的产生和发展,并解释了在批判医学人类学理论体系下的其核心概念,指出:在人类学的框架内,用批判的眼光解决医疗体制中所存在的问题是非常有意义的;在政治经济发展全球化的今天,致力于建立一个多元文化批判的完整体系可以促使人们更深刻地了解医疗和医疗护理。     

Exotoxin A-eEF2 complex structure indicates ADP ribosylation by ribosome mimicry

The bacteria causing diphtheria, whooping cough, cholera and other diseases secrete mono-ADP-ribosylating toxins that modify intracellular proteins. Here, we describe four structures of a catalytically active complex between a fragment of Pseudomonas aeruginosa exotoxin A (ETA) and its protein substrate, translation elongation factor 2 (eEF2). The target residue in eEF2, diphthamide (a modified histidine), spans across a cleft and faces the two phosphates and a ribose of the non-hydrolysable NAD+ analogue, betaTAD. This suggests that the diphthamide is involved in triggering NAD+ cleavage and interacting with the proposed oxacarbenium intermediate during the nucleophilic substitution reaction, explaining the requirement of diphthamide for ADP ribosylation. Diphtheria toxin may recognize eEF2 in a manner similar to ETA. Notably, the toxin-bound betaTAD phosphates mimic the phosphate backbone of two nucleotides in a conformational switch of 18S rRNA, thereby achieving universal recognition of eEF2 by ETA.     

Preparation of monoaminoxydase

Zusammenfassung Eine einfache Methode zur Gewinnung eines Extraktes (Pulver) von starker Monoaminoxydase-Aktivität aus Hunde- oder Kaninchennieren wird beschrieben. Differentiales Zentrifugieren und rasches Einfrieren sind die wichtigsten Schritte dieser Methode. Die enzymatische Aktivität des Präparates bleibt über mehrere Monate erhalten.

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This investigation was supported in part by the United States Public Health Service, Grant H 444 (C 9) and by United States Army Grant DA-49-007-MD-429.     

Time-activity budgets of drake Gadwall and Northern Shovelers on industrial cooling ponds during late winter and early spring in central Utah

Time-activity budgets of drake Gadwall and Northern Shoveler ducks were studied in the winter of 1985. Total duck numbers peaked in mid-March. Gadwall numbers increased from late January to mid-March and then declined, while Northern Shoveler numbers declined from late January to mid-February and then increased to mid-March before declining. Behavior categories considered in the time-activity budgets were flying, preening, swimming, courtship, feeding, and resting. Time allocated to these different activities varied for both duck species, with feeding being the only behavior pattern wherein differences were significant. Gadwalls spent 58% of their time feeding. Northern Shovelers only 26%. Possible reasons for these differences are suggested.     

Frequent mutation of histone-modifying genes in non-Hodgkin lymphoma

Follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) are the two most common non-Hodgkin lymphomas (NHLs). Here we sequenced tumour and matched normal DNA from 13 DLBCL cases and one FL case to identify genes with mutations in B-cell NHL. We analysed RNA-seq data from these and another 113 NHLs to identify genes with candidate mutations, and then re-sequenced tumour and matched normal DNA from these cases to confirm 109 genes with multiple somatic mutations. Genes with roles in histone modification were frequent targets of somatic mutation. For example, 32% of DLBCL and 89% of FL cases had somatic mutations in MLL2, which encodes a histone methyltransferase, and 11.4% and 13.4% of DLBCL and FL cases, respectively, had mutations in MEF2B, a calcium-regulated gene that cooperates with CREBBP and EP300 in acetylating histones. Our analysis suggests a previously unappreciated disruption of chromatin biology in lymphomagenesis.     

Stimulation of oligodendroglial proliferation and maturation by interleukin-2

There exists considerable evidence that the growth of glial cells can be influenced by T-cell-derived lymphokines and monokines. Astrocytes proliferate in the presence of mitogen- or antigen-stimulated T-cell supernatants, supernatants from human T-lymphotropic virus (HTLV)-transformed T cells, and purified human interleukin-1 (IL-1; ref. 4). Oligodendrocytes proliferate and differentiate when incubated with supernatants from mitogen-activated or HTLV-transformed T cells. In addition, we have recently purified a T-cell-derived lymphokine of relative molecular mass 30,000, termed glial growth promoting factor (GGPF), which specifically stimulates the proliferation of oligodendrocytes. The traditional role of interleukins 1 and 2 is in the initiation, propagation and regulation of the immune response. IL-1, released by a variety of cells including monocytes, stimulates T cells to produce IL-2; IL-2 in turn induces the expansion of T cells that is critical for immune responsiveness. Recently, IL-2 has been shown to induce B-cell proliferation and immunoglobulin secretion, indicating that its action is not restricted to T cells. We now report that recombinant human IL-2 influences the growth of glial cells--specifically, the proliferation and differentiation of oligodendrocytes. IL-2 may have a role in the inflammatory neural lesions of multiple sclerosis patients and in the growth of brain glia during injury or disease.     

Factors controlling structural and floristic variation of riparian zones in a mountainous landscape of the western United States

We examined landscape patterns in the physical conditions and vegetative composition of montane riparian zones to identify their most important sources of variation. Information on plant species cover and on physical characteristics that occur at coarse, medium, and fine scales was collected for 144 riparian plots located throughout the Lake Tahoe Basin, which straddles the California-Nevada border in the western United States. Constrained and unconstrained ordination analyses were used to identify the most important correlates of physical form and plant species composition. Through multivariate analysis of environmental variables (principal components analysis), vegetation data (detrended correspondence analysis), and the combined relationship between the environmental and vegetation data (canonical correspondence analysis), we consistently found that the greatest variation occurred along a gradient of decreasing valley width, decreasing stream sinuosity, and increasing stream slope. Although surface characteristics reflected a 2nd important source of variation in physical conditions, plant species distribution was not strongly correlated with riparian surface conditions. Strong correlations among physical variables that occur at different scales, such as between valley form and geofluvial surface and between geofluvial surface and surface conditions, support the use of a physically based hierarchical framework for organizing riparian zones within the landscape. Such a hierarchical framework would be useful for interpreting patterns in riparian structure and process at different scales and could be applied to riparian zones in other mountain landscapes of the western United States and elsewhere. Moreover, our finding that riparian plant species composition is most strongly correlated with environmental variables that occur at coarse to moderate scales, most of which can be derived from existing data, supports the idea that modeling montane riparian community distribution using topographic and remotely sensed data could be useful; however, a large degree of species variation, unexplained by the variables we collected, indicates that other variables, perhaps disturbance regime, should be included in such a venture. Nomenclature: Hickman (1993).     

社区外展:广州吸毒者的个案研究

通过描述发现和接近吸毒者群体的过程 ,分析广州地区静脉注射吸毒者的类型和特点以及他们大致的分布地点 ,总结了在艾滋病研究中如何应用人类学知识从事“社区外展活动”。最后 ,文章总结了这次外展活动的经验和教训 ,对今后研究隐藏在社区中的静脉吸毒的招募方法提出了建议。