Hämatologische Störungen bei Intensivpatienten

This final issue of the series "Emergency and intensive care therapy for hematooncological diseases" reviews cytopenias in intensive care patients who do not offer any oncological or haematological problems in their medical history. Anaemia is a very common problem in the intensive care setting. We highlight aetiological aspects of anaemia in critically ill patients and discuss therapeutical options like substitution of blood and application of erythropoietin, respectively. The second paragraph focuses on leukocytopenia and agranulocytosis, their causation and therapy and among other things the application of G-CSF (Granulocyte colony-stimulating factor). Last but not least, we deal with thrombocytopenia, especially heparin-induced thrombocytopenia.     

LPS resistance in monocytic cells caused by reverse signaling through transmembrane TNF (mTNF) is mediated by the MAPK/ERK pathway

The transmembrane form of tumor necrosis factor (mTNF), expressed on activated monocytes (MO) and macrophages (MPhi), is able to induce apoptosis in human endothelial cells (EC). Apoptosis is mediated by two distinct mechanisms: direct cell contact and a yet-unidentified soluble protein, death factor X. In addition, mTNF acts as a receptor that transduces a "reverse signal" into MO/MPhi when bound to the TNF receptor on EC. Reverse signaling by mTNF confers resistance to bacterial lipopolysaccharide (LPS). Stimulation of reverse signaling by mTNF blocks the ability of MO/MPhi to produce death factor X and proinflammatory cytokines. We have investigated which signaling pathways are used by mTNF acting as receptor. Reverse signaling triggers two independent pathways that can be distinguished by protein kinase C (PKC) inhibitors. The suppression of LPS-induced death factor X is dependent on PKC, whereas the suppression of LPS-mediated cytokine release is not. LPS and reverse signaling stimulate the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway. It is interesting that the activation of reverse signaling by mTNF renders MO/MPhi refractory to a subsequent activation of the MAPK/ERK pathway by LPS. Thus, reverse signaling achieves LPS resistance in monocytic cells through interference with key signal-transduction pathways.     

TCRs with high affinity for foreign pMHC show self-reactivity

T cells with high-affinity T cell receptors (TCRs) for a foreign peptide-major histocompatibility complex (pMHC) appear to be negatively selected, even though they have never seen the foreign antigen. To examine how this process operates, we used in vitro yeast display to isolate high-affinity TCRs from the T cell clone 2C. The TCRs showed fast on-rates, which were consistent with reduced CDR (complementarity determining region) flexibility, and cross-reactivity with other cognate pMHCs. T cell hybridomas transfected with a high-affinity TCR were stimulated by endogenous self-pMHC, which suggested that T cells bearing the TCR would be negatively selected. The immune system appears to maintain a repertoire of flexible, low-affinity TCRs at the expense of more effective high-affinity TCRs.     

Low incidence of transplant-related complications in patients with chronic release of tumor necrosis factor-alpha before admission to bone marrow transplantation: a clinical correlate of cytokine desensitization?

To investigate the role of tumor necrosis factor-alpha (TNF-alpha) released by activated macrophages, sequential serum samples of 120 patients undergoing bone marrow transplantation (BMT) were analyzed by enzyme-linked immunosorbent assay. De novo increases in serum TNF-alpha levels were correlated with the development of acute endothelial complications as well as acute graft-versus-host disease. In addition, the analysis of time courses revealed a different capacity of TNF-alpha regulation at various phases of BMT. While patients with acute TNF-alpha release in the first 2 weeks of BMT had a significantly enhanced incidence of complications, a subgroup of 9 patients with chronic asymptomatic release of TNF-alpha before admission to BMT was observed. These patients were protected from complications in the course of the first 6 months of BMT. Our observations indicate the occurrence of desensitization for TNF-alpha, as it is also reported after repeated injections of TNF-alpha or endotoxin in experimental models.     

Exploiting T cell receptor genes for cancer immunotherapy

Adoptive antigen-specific immunotherapy is an attractive concept for the treatment of cancer because it does not require immunocompetence of patients, and the specificity of transferred lymphocytes can be targeted against tumour-associated antigens that are poorly immunogenic and thus fail to effectively trigger autologous T cell responses. As the isolation and in vitro expansion of antigen-specific lymphocytes is difficult, 'conventional' adoptive T cell therapy can only be carried out in specialized centres in small numbers of patients. However, T cell receptor (TCR) genes isolated from antigen-specific T cells can be exploited as generic therapeutic molecules for 'unconventional' antigen-specific immunotherapy. Retroviral TCR gene transfer into patient T cells can readily produce populations of antigen-specific lymphocytes after a single round of polyclonal T cell stimulation. TCR gene modified lymphocytes are functionally competent in vitro, and can have therapeutic efficacy in murine models in vivo. TCR gene expression is stable and modified lymphocytes can develop into memory T cells. Introduction of TCR genes into CD8(+) and CD4(+) lymphocytes provides an opportunity to use the same TCR specificity to produce antigen-specific killer and helper T lymphocytes. Thus, TCR gene therapy provides an attractive strategy to develop antigen-specific immunotherapy with autologous lymphocytes as a generic treatment option.     

Patterns of canal and otolith afferent input convergence in frog second-order vestibular neurons

Second-order vestibular neurons (2 degrees VN) were identified in the isolated frog brain by the presence of monosynaptic excitatory postsynaptic potentials (EPSPs) after separate electrical stimulation of individual vestibular nerve branches. Combinations of one macular and the three semicircular canal nerve branches or combinations of two macular nerve branches were stimulated separately in different sets of experiments. Monosynaptic EPSPs evoked from the utricle or from the lagena converged with monosynaptic EPSPs from one of the three semicircular canal organs in ~30% of 2 degrees VN. Utricular afferent signals converged predominantly with horizontal canal afferent signals (74%), and lagenar afferent signals converged with anterior vertical (63%) or posterior vertical (37%) but not with horizontal canal afferent signals. This convergence pattern correlates with the coactivation of particular combinations of canal and otolith organs during natural head movements. A convergence of afferent saccular and canal signals was restricted to very few 2 degrees VN (3%). In contrast to the considerable number of 2 degrees VN that received an afferent input from the utricle or the lagena as well as from one of the three canal nerves (~30%), smaller numbers of 2 degrees VN (14% of each type of 2 degrees otolith or 2 degrees canal neuron) received an afferent input from only one particular otolith organ or from only one particular semicircular canal organ. Even fewer 2 degrees VN received an afferent input from more than one semicircular canal or from more than one otolith nerve (~7% each). Among 2 degrees VN with afferent inputs from more than one otolith nerve, an afferent saccular nerve input was particularly rare (4-5%). The restricted convergence of afferent saccular inputs with other afferent otolith or canal inputs as well as the termination pattern of saccular afferent fibers are compatible with a substrate vibration sensitivity of this otolith organ in frog. The ascending and/or descending projections of identified 2 degrees VN were determined by the presence of antidromic spikes. 2 degrees VN mediating afferent utricular and/or semicircular canal nerve signals had ascending and/or descending axons. 2 degrees VN mediating afferent lagenar or saccular nerve signals had descending but no ascending axons. The latter result is consistent with the absence of short-latency macular signals on extraocular motoneurons during vertical linear acceleration. Comparison of data from frog and cat demonstrated the presence of a similar organization pattern of maculo- and canal-ocular reflexes in both species.     

Exchange lists: revised 1986

A committee composed of members of The American Dietetic Association and the American Diabetes Association has revised Exchange List for Meal Planning. Changes were made, as deemed necessary, on the basis of nutritional recommendations for persons with diabetes as understood in 1986. Major changes include rewriting the text to make it more useful in the education of persons with diabetes; changing the order of the exchange lists to emphasize a high-carbohydrate, high-fiber diet, as well as to better reflect the order of foods in menu planning; adding symbols to foods high in fiber and sodium; changing nutritive values for the starch/bread and fruit lists; adding lists of combination foods, free foods, and foods recommended only for occasional use; developing a data base; and initiating a plan for field testing and evaluation. The committee also developed a simplified meal planning tool, Healthy Food Choices, to be used for initial or "survival" level education. In poster format, foods are grouped by calories into six food groups. Approximate portion sizes of commonly used foods are listed. Blank lines are provided for the nutrition counselor to write in a suggested menu or meal plan for the client. Because the booklet does not use the word "diabetes" specifically, it is appropriate as a general teaching tool.     

Autotrophy as a predominant mode of carbon fixation in anaerobic methane-oxidizing microbial communities

The methane-rich, hydrothermally heated sediments of the Guaymas Basin are inhabited by thermophilic microorganisms, including anaerobic methane-oxidizing archaea (mainly ANME-1) and sulfate-reducing bacteria (e.g., HotSeep-1 cluster). We studied the microbial carbon flow in ANME-1/ HotSeep-1 enrichments in stable-isotope–probing experiments with and without methane. The relative incorporation of ¹³C from either dissolved inorganic carbon or methane into lipids revealed that methane-oxidizing archaea assimilated primarily inorganic carbon. This assimilation is strongly accelerated in the presence of methane. Experiments with simultaneous amendments of both ¹³C-labeled dissolved inorganic carbon and deuterated water provided further insights into production rates of individual lipids derived from members of the methane-oxidizing community as well as their carbon sources used for lipid biosynthesis. In the presence of methane, all prominent lipids carried a dual isotopic signal indicative of their origin from primarily autotrophic microbes. In the absence of methane, archaeal lipid production ceased and bacterial lipid production dropped by 90%; the lipids produced by the residual fraction of the metabolically active bacterial community predominantly carried a heterotrophic signal. Collectively our results strongly suggest that the studied ANME-1 archaea oxidize methane but assimilate inorganic carbon and should thus be classified as methane-oxidizing chemoorganoautotrophs.     

Public health decisions: Actions and consequences

The goal of public health is to promote the best possible health for the whole population. Public health issues are numerous and can be unbelievably complex in form, scope, and possible consequence. Most public health decisions involve assessing several different options, weighing the respective benefits and risks of those options, and making difficult decisions that hopefully provide the greatest benefit to the affected populations. Many risk management decisions involve a variety of societal factors which modify risk assessment choices. The purpose of this paper is to point out difficulties in making decisions that impact public health. The intent of such decisions is to improve public health, but as illustrated in the paper, there can be unintended adverse consequences. Such unplanned issues require continued attention and efforts for responsible officials in the protection of environmental public health. This article presents examples of such events, when in the past, it was necessary to assess and regulate a number of potentially hazardous chemicals commonly used as insecticides, gasoline additives, and wood preservatives.     

Proteomics applied to the clinical follow-up of patients after allogeneic hematopoietic stem cell transplantation

A phase 1 diagnostic study was performed to evaluate a novel technology for clinical proteomic research based on capillary electrophoresis and mass spectrometry. Urine from 40 patients after hematopoietic stem cell transplantation (HSCT; 35 allogeneic, 5 autologous) and 5 patients with sepsis was collected for a period of 100 days and analyzed. More than 1000 different polypeptides could be detected in individual samples. Polypeptide patterns excreted in the urine of patients were significantly different from those of healthy volunteers. No significant differences were detected comparing different conditioning regimens. The aim of this study was to identify polypeptide patterns functioning as early indicators of graft-versus-host disease (GVHD). Eighteen patients developed GVHD after allogeneic HSCT. Sixteen differentially excreted polypeptides formed a pattern of early GVHD markers, allowing discrimination of GVHD from patients without complications with 82% specificity and 100% sensitivity, cross-validated. Inclusion of 13 sepsis-specific polypeptides allowed us to distinguish sepsis from GVHD with a specificity of 97% and a sensitivity of 100%. Sequencing 2 prominent GVHD-indicative polypeptides led to the identification of a peptide from leukotriene A4 hydrolase and a peptide from serum albumin. The data reveal that capillary electrophoresis and mass spectrometry allow identification of biomarkers for a variety of diseases or related complications.