E.U. paediatric MOG consortium consensus: Part 4 - Outcome of paediatric myelin oligodendrocyte glycoprotein antibody-associated disorders.

There is increasing knowledge on the role of antibodies against myelin oligodendrocyte glycoprotein (MOG-abs) in acquired demyelinating syndromes and autoimmune encephalitis in children. Better understanding and prediction of outcome is essential to guide treatment protocol decisions. Therefore, this part of the Paediatric European Collaborative Consensus provides an oversight of existing knowledge of clinical outcome assessment in paediatric MOG-ab-associated disorders (MOGAD). The large heterogeneity in disease phenotype, disease course, treatment and follow-up protocols is a major obstacle for reliable prediction of outcome. However, the clinical phenotype of MOGAD appears to be the main determinant of outcome. Patients with a transverse myelitis phenotype in particular are at high risk of accruing neurological disability (motor and autonomic), which is frequently severe. In contrast, having a single episode of optic neuritis any time during disease course is broadly associated with a lower risk of persistent disability. Furthermore, MOG-ab-associated optic neuritis often results in good functional visual recovery, although retinal axonal loss may be severe. The field of cognitive and behavioural outcome and epilepsy following demyelinating episodes has not been extensively explored, but in recent studies acute disseminated encephalomyelitis (-like) phenotype in the young children was associated with cognitive problems and epilepsy in long-term follow-up. In conclusion, main domains of importance in determining clinical outcome in paediatric MOGAD are visual, motor, autonomic and cognitive function. A standardised evaluation of these outcome domains in all children is of importance to allow adequate rehabilitation and follow-up.

E.U. paediatric MOG consortium consensus: Part 1 - Classification of clinical phenotypes of paediatric myelin oligodendrocyte glycoprotein antibody-associated disorders.

Over the past few years, increasing interest in the role of autoantibodies against myelin oligodendrocyte glycoprotein (MOG-abs) as a new candidate biomarker in demyelinating central nervous system diseases has arisen. MOG-abs have now consistently been identified in a variety of demyelinating syndromes, with a predominance in paediatric patients. The clinical spectrum of these MOG-ab-associated disorders (MOGAD) is still expanding and differs between paediatric and adult patients. This first part of the Paediatric European Collaborative Consensus emphasises the diversity in clinical phenotypes associated with MOG-abs in paediatric patients and discusses these associated clinical phenotypes in detail. Typical MOGAD presentations consist of demyelinating syndromes, including acute disseminated encephalomyelitis (ADEM) in younger, and optic neuritis (ON) and/or transverse myelitis (TM) in older children. A proportion of patients experience a relapsing disease course, presenting as ADEM followed by one or multiple episode(s) of ON (ADEM-ON), multiphasic disseminated encephalomyelitis (MDEM), relapsing ON (RON) or relapsing neuromyelitis optica spectrum disorders (NMOSD)-like syndromes. More recently, the disease spectrum has been expanded with clinical and radiological phenotypes including encephalitis-like, leukodystrophy-like, and other non-classifiable presentations. This review concludes with recommendations following expert consensus on serologic testing for MOG-abs in paediatric patients, the presence of which has consequences for long-term monitoring, relapse risk, treatments, and for counselling of patient and families. Furthermore, we propose a clinical classification of paediatric MOGAD with clinical definitions and key features. These are operational and need to be tested, however essential for future paediatric MOGAD studies.

Neuronal autoantibodies associated with cognitive impairment in melanoma patients.

BACKGROUND: Cancer-related cognitive impairment is an important complication in cancer patients, yet the underlying mechanisms remain unknown. Over the last decade, the field of paraneoplastic neurological syndromes has been dramatically changed by the discovery of new neuronal autoantibodies, some of them associated with cognitive impairment. We aimed to assess the prevalence of neuronal autoantibodies in melanoma patients and their association with neurological and cognitive dysfunction. PATIENTS AND METHODS: A total of 157 consecutive melanoma patients with a median age of 63 years were recruited at the Department of Dermatology, Charité-Universitätsmedizin Berlin and tested for neuronal autoantibodies. A comprehensive neuropsychological assessment was carried out in a selected subgroup of 84 patients after exclusion of patients with confounding factors for a cognitive dysfunction, including brain metastases, relevant medication, and neurological disorders. RESULTS: Neuronal autoantibodies were found in 22.3% of melanoma patients. The most frequent antibodies were IgA/IgM anti-NMDAR antibodies. Applying the International Cognition and Cancer Task Force criteria, 36.9% had cognitive impairment, however, with a threefold higher odds in antibody-positive compared with antibody-negative patients (57.1% versus 30.2%, OR = 3.1, 95% CI: 1.1 to 8.6; P = 0.037). In patients with anti-NMDAR antibodies, this impairment increased with higher antibody titers (P = 0.007). Antibody-positive patients had a significantly impaired overall cognitive performance (z-value: -0.38 ± 0.69 versus 0.00 ± 0.56; P = 0.014) as well as significant impairments in tests of memory, attention, and executive function. In a multiple linear regression analysis, autoantibodies were an independent risk factor for cognitive impairment (B = -0.282; 95% CI: -0.492 to -0.071; P = 0.009). Autoantibody seropositivity was associated with immune checkpoint inhibitor treatment and a history of autoimmune diseases. CONCLUSIONS: A large number of melanoma patients harbor neuronal autoantibodies that are associated with significant cognitive impairment affecting memory, attention, and executive function. Neuronal autoantibodies might represent a pathophysiological factor and possible biomarker in the development of cancer-related cognitive impairment.

Theoretical analysis of single-molecule force spectroscopy experiments: heterogeneity of chemical bonds.

We show that the standard theoretical framework in single-molecule force spectroscopy has to be extended to consistently describe the experimental findings. The basic amendment is to take into account heterogeneity of the chemical bonds via random variations of the force-dependent dissociation rates. This results in a very good agreement between theory and rupture data from several different experiments.

Theoretical analysis of dynamic force spectroscopy experiments on ligand-receptor complexes.

The forced rupture of single chemical bonds in biomolecular compounds (e.g. ligand-receptor systems) as observed in dynamic force spectroscopy experiments is addressed. Under the assumption that the probability of bond rupture depends only on the instantaneously acting force, a data collapse onto a single master curve is predicted. For rupture data obtained experimentally by dynamic AFM force spectroscopy of a ligand-receptor bond between a DNA and a regulatory protein we do not find such a collapse. We conclude that the above mentioned, generally accepted assumption is not satisfied and we discuss possible explanations.

[Quality of diagnostic procedures and frequency of endoscopically defined diseases of the upper gastrointestinal tract]. / Zur Qualität der Diagnostik und zur Häufigkeit endoskopisch definierter Erkrankungen des oberen Gastrointestinaltraktes.

The aim of this clinical investigation was to register the frequency of endoscopically defined diseases of the upper intestinal tract in a given region (Münster and Münsterland) within the period of one year (1.8.1999-31.7.2000). Furthermore, we tried to get an impression on the quality of the upper intestinoscopies by standardised conditions which had been developed by a steering committee (endoscopists and pathologists). 20 physicians (internal specialists and gastroenterologists) examined non-preselected patients and registered all relevant findings in the upper intestinal tract. The following items were of special interest: sex, age, operations in the past, indication, way of preparation, local findings (in the upper intestinal tract), and histological assessment. The examination forms were gathered, checked for completeness and evaluated statistically. Within the given period 8859 examinations forms (45.2% male and 54% female) could be evaluated. In 16% of the patients a reflux oesophagitis was diagnosed, three times more frequently than could have been expected anamnestically regarding the patients' complaints. In 274 patients (3%) the endoscopist suspected a Barrett's oesophagus; the according histological examination confirmed this suspicion in only 125 cases. Furthermore 17 adenocarcinomas and 13 squamous cell carcinomas were found. Macroscopically 44 polyps were registered but not all of them were biopsied. In 257 patients oesophageal varices (of varying degrees) were described. Only in 30.7% of the patients a H. pylori infection (diagnosed by urease test and by histological examination) was detected in the mucosa of the stomach. In 172 patients a gastritis was macroscopically suspected but the following histological assessments were not sufficient. The prevalence of gastric ulcers was 10 %, higher than the prevalence of duodenal ulcers. Only in 50% of the patients with a duodenal ulcer a H. pylori infection could be detected. In 51 cases carcinomas (diagnosis histologically confirmed) were found with the same ratio of the diffuse type and the intestinal type. In 18 patients a carcinoma could be detected in the neighbouring area of gastric ulcers. The endoscopic findings in this investigation do not differ significantly from the results found in literature. It is important that there are more gastric ulcers than duodenal ulcers. This can be explained by the frequent use of PPIs which are prescribed additionally to NSARs and ASS. The deficits of histological diagnostics on Barett's oesophagus and gastritis were remarkable. An improvement of the endoscopic and histologic assessment quality by valid standards systematically applied should be aimed at in future. Furthermore it could be helpful to use the same nomenclature for pathologic findings to intensify the co-operation between the physicians in hospitals and the practitioners.

The essential HupB and HupN proteins of Pseudomonas putida provide redundant and nonspecific DNA-bending functions.

A protein mixture containing two major components able to catalyze a beta-recombination reaction requiring nonspecific DNA bending was obtained by fractionation of a Pseudomonas putida extract. N-terminal sequence analysis and genomic data base searches identified the major component as an analogue of HupB of Pseudomonas aeruginosa and Escherichia coli, encoding one HU protein variant. The minor component of the fraction, termed HupN, was divergent enough from HupB to predict a separate DNA-bending competence. The determinants of the two proteins were cloned and hyperexpressed, and the gene products were purified. Their activities were examined in vitro in beta-recombination assays and in vivo by complementation of the Hbsu function of Bacillus subtilis. HupB and HupN were equally efficient in all tests, suggesting that they are independent and functionally redundant DNA bending proteins. This was reflected in the maintenance of in vivo activity of the final sigma54 Ps promoter of the toluene degradation plasmid, TOL, which requires facilitated DNA bending, in DeltahupB or DeltahupN strains. However, hupB/hupN double mutants were not viable. It is suggested that the requirement for protein-facilitated DNA bending is met in P. putida by two independent proteins that ensure an adequate supply of an essential cellular activity.

Occurrence and expression of glutathione-S-transferase-encoding bphK genes in Burkholderia sp. strain LB400 and other biphenyl-utilizing bacteria.

The gene bphK of Burkholderia sp. strain LB400 has previously been shown to be located within the bph locus, which specifies the degradation of biphenyl (BP) and chlorobiphenyls, and to encode a glutathione S-transferase (GST) which accepts 1-chloro-2,4-dinitrobenzene (CDNB) as substrate. The specific physiological role of this gene is not known. It is now shown that the gene is expressed in the parental organism and that GST activity is induced more than 20-fold by growth of the strain on BP relative to succinate when these compounds serve as sole carbon source. Approximately the same induction factor was observed for 2,3-dihydroxybiphenyl 1,2-dioxygenase activity, which is encoded by the 5'-adjacent bphC gene. This suggests that the expression of bphK is coregulated with the expression of genes responsible for the catabolism of BP. A bphK probe detected only a single copy of the gene in strain LB400. A spontaneous BP- mutant of the organism neither gave a signal with the bphK probe nor showed CDNB-accepting GST activity, suggesting that this activity is solely encoded by bphK. Complementation of the mutant with a bph gene cluster devoid of bphK restored the ability to grow on BP, indicating that bphK is not essential for utilization of this carbon source. BphK activity proved to be almost unaffected by up to 100-fold differences in proton concentration or ionic strength. The enzyme showed a narrow range with respect to a variety of widely used electrophilic GST substrates, accepting only CDNB. A number of established laboratory strains as well as novel isolates able to grow on BP as sole carbon and energy source were examined for BphK activity and the presence of a bphK analogue. CDNB assays, probe hybridizations and PCR showed that several, but not all, BP degraders possess this type of GST activity and/or a closely related gene. In all bacteria showing BphK activity, this was induced by growth on BP as sole carbon source, although activity levels differed by up to 10-fold after growth on BP and by up to 60-fold after growth on succinate. This resulted in a variation of induction factors between 2 and 30. In the majority of bphK+ bacteria examined, the gene appeared to be part of LB400-like bph gene clusters. DNA sequencing revealed almost complete identity of bphK genes from five different bph gene clusters. These results suggest that bphK genes, although not essential, fulfill a strain-specific function related to the utilization of BPs by their host organisms. The usefulness of BphK as a reporter enzyme for monitoring the expression of catabolic pathways is discussed.

Expression of intercellular adhesion molecule-1 is regulated by the actin network in epidermoid carcinoma cells.

Expression of the cell surface protein intercellular adhesion molecule-1 (ICAM-1) is a prerequisite for the interaction of a large variety of cells with leukocytes. Constitutive expression of ICAM-1 in human epidermoid carcinoma cells is low, but is inducible through inflammatory cytokines including interferon gamma (INF gamma). Disruption of the actin cytoskeleton with dehydrocytochalasin B (CB) increased constitutive and potentiated INF gamma-induced ICAM-1 cell surface expression, but did not alter formation of soluble ICAM-1. Actinomycin D inhibited CB-induced ICAM-1 surface expression and CB increased the steady-state levels of ICAM-1 transcripts. However, CB did not alter the glyceralaldehyde-3-phosphate dehydrogenase mRNA levels and the ICAM-1 mRNA half-life. These studies indicate that in human epidermoid carcinoma cells the actin cytoskeleton regulates ICAM-1 transcription and cell surface expression.

[Incidents, events and complications in the perioperative period in normal and malnurished patients--results of 23,056 patients]. / Zwischenfälle, Ereignisse und Komplikationen in der perioperativen Phase bei normal- und fehlernährten Patienten--Ergebnisse von 23,056 Anästhesien.

AIM: Prevalence of cardiovascular risk factors in anaesthetic patients and perioperative pitfalls, events and complications (PECs) in different nutritional states were examined. The results should contribute to a current project of the German Society of Anaesthesiology and Intensive Care, established for quality assurance. METHOD: Preoperative data (age, sex, defined preexisting diseases, nutritional state, grade of urgency and ASA-class) were integrated in an automatically readable paper record, as well as the perioperative interventions and events, type of anaesthesia, and kind of operation. The records were routinely in use for every patient. After control and correction the data were stored in a modern data base. Data of patients under 16 years of age and incomplete sets of data were excluded from analysis. MAIN RESULTS: From July 1, 1992 to December 31, 1993 23,056 anaesthesias were recorded, 5,852 (25.4%) of them with a total of 8,107 PECs. 17,255 patients had normal body weight and 23% of them PECs. 4,484 obese (but not extremely) patients had a PEC rate of 31.2%, 330 extremely obese patients had a PEC rate of 38.2%, 966 patients with underweight (but not extremely) had a PEC rate of 36.1% and 21 with extreme underweight had a PEC rate of 38.1%. Obese patients had a higher prevalence of preexisting cardiovascular disturbances (angina pectoris, myocardial infarction and hypertension) and tended to a higher incidence of perioperative hypertensive, bronchospastic and hypoxic events as well as more difficulties in application of regional anaesthesia. Young adult patients (16-39 years) had a PEC rate of 14% in case of normal nutritional state but of 20% in case of obesity. The incidence of respiratory PECs and of PECs of higher severity was almost double in obese young patients compared to normal weight patients of the same age. When preoperative cardiovascular disease was known there was little difference between the different states of nutrition in respect of perioperative PECs. CONCLUSIONS: Nutritional disorder is an important epidemiological factor in anaesthesia. Particularly in younger patients without defined preoperative cardiovascular disturbance but with obesity the anaesthesist may be surprised by a remarkable incidence of relevant problems during and immediately after anaesthesia. We should consider the possible phenomenon that we are underestimating the anaesthetic challenge in young obese patients in a "healthy" cardiovascular state.

IgA protease from Neisseria gonorrhoeae inhibits exocytosis in bovine chromaffin cells like tetanus toxin.

When tetanus toxin from Clostridium tetani or IgA protease from Neisseria gonorrhoeae is translocated artificially into the cytosol of chromaffin cells, both enzymes inhibit calcium-induced exocytosis, which can be measured by changes in membrane capacitance. The block of exocytosis caused by both proteases cannot be reversed by enforced stimulation with increased calcium concentration. This effect differs from the botulinum A neurotoxin-induced block of exocytosis that can be overcome by elevation of the intracellular calcium concentration. Tetanus toxin is about 50-fold more potent than IgA protease in cells stimulated by carbachol. In this case, the release of [3H]noradrenaline was determined. Trypsin and endoprotease Glu-C are hardly effective and only at concentrations that disturb the integrity of the cells. Like tetanus toxin, IgA protease also splits synaptobrevin II, though at a different site of the molecule. However, unlike tetanus toxin, it does not cleave cellubrevin. It is concluded that the membranes of chromaffin vesicles contain synaptobrevin II, which, as in neurons, appears to play a crucial part in exocytosis.

Processing of tetanus and botulinum A neurotoxins in isolated chromaffin cells.

Tetanus and botulinum A neurotoxins were introduced into the cytosol of chromaffin cells by means of an electric field in which the plasma membrane is forced to form pores of approximately 1 micron at the sites facing the electrodes. As demonstrated by electron microscopy, both [125I] and gold-labelled tetanus toxin (TeTx) diffuse through these transient openings. Dichain-TeTx, with its light chain linked to the heavy chain by means of a disulfide bond, causes the block of exocytosis to develop more slowly than does the purified light chain. The disulfide bonds, which in both toxins hold the subunits together, were cleaved by the intrinsic thioredoxin-reductase system. Single chain TeTx, in which the heavy and light chains are interconnected by an additional peptide bond, was far less effective than dichain-TeTx at blocking exocytosis, which indicates that proteolysis is the rate-limiting step. The toxins were degraded further to low-molecular weight fragments which, together with intact toxins and subunits, were released by the cells. The intracellular half-life of [125I] dichain-TeTx was approximately three days. The number of light-chain molecules required to maintain exocytosis block in a single cell, as calculated by two different methods, was less than 10. The long duration of tetanus poisoning may result from the persistence of intracellular toxin due to scarcity of free cytosolic proteases. This may also hold for the slow recovery from botulism.

Specific antibodies against the Zn(2+)-binding domain of clostridial neurotoxins restore exocytosis in chromaffin cells treated with tetanus or botulinum A neurotoxin.

Although tetanus and botulinum A neurotoxins are ineffective in cultured chromaffin cells, they will inhibit carbachol-induced release of noradrenaline provided they gain access to the cytosol either through artificial pores generated in the plasma membrane or by binding to incorporated exogenous gangliosides. The block of exocytosis persists for weeks followed by a slow recovery of cell function. When specific anti-botulinum A toxin antibodies are introduced into cells through pores after manifestation of the block by botulinum A neurotoxin, restoration of exocytotic function is accelerated and fully reestablished within 4 days. The same time course of restoration is seen with anti-tetanus toxin antibodies in cells poisoned by tetanus toxin. Since the light chains of the toxins are enzymatically active, we have introduced polyclonal and monoclonal anti-light chain antibodies into the cytosol. Of all light chain antibodies tested, only those directed against the peptide homologous to the zinc-binding sequence, which is present in both neurotoxins, restored exocytosis regardless of which toxin caused the block. These results indicate that the zinc-binding domain is directly involved in the interaction of the light chains with their substrates and that the toxins have to be present continuously to maintain the block.

Cyclosporin A inhibits T cell receptor-induced interleukin-2 synthesis of human T lymphocytes by selectively preventing a transmembrane signal transduction pathway leading to sustained activation of a protein kinase C isoenzyme, protein kinase C-beta.

Stimulation of human peripheral blood lymphocytes via T cell receptor/CD3 complex resulted in a bimodal activation of protein kinase(s) C (PKC). Within 10 min of stimulation PKC-alpha was translocated to, and thus activated in, the plasma membranes of human lymphocytes, followed by a fast dissociation of this isotype from the plasma membrane. This short term activation and translocation PKC-alpha proved to be cyclosporin A (CsA) insensitive. After 90 min of stimulation PKC-beta was translocated to and remained bound to the plasma membranes for up to 4 h. Preincubation of human lymphocytes with 200 ng/ml CsA specifically and completely abolished the sustained activation of PKC-beta. Neither the phorbol ester-induced direct activation of PKC nor the specific activity of the plasma membrane-bound enzyme was influenced by CsA, suggesting that a signal transduction pathway leading to sustained activation of PKC-beta was influenced by the immunosuppressive agent. In fact, CsA inhibited, in a concentration-dependent manner, the activation of lysophosphatid acyltransferase-catalyzed elevated incorporation of cis-polyunsaturated fatty acids into plasma membrane phospholipids. While interleukin-2 (IL-2) synthesis and cellular proliferation were completely inhibited by 200 ng/ml CsA in BMA 030- or BMA 031-stimulated cells, expression of high-affinity IL-2 receptors was not influenced by the immunosuppressive drug. These results suggest that synthesis and expression of high-affinity IL-2 receptors might be regulated by a signal-transducing pathway involving activation and translocation of PKC-alpha. Lysophosphatid acyltransferase-catalyzed incorporation of cis-polyunsaturated fatty acids might represent another mechanism of signal transduction implicated in the activation and translocation of PKC-beta, which is specifically inhibited by CsA. Neutralization of PKC-beta by introducing anti-PKC-beta antibodies prevented IL-2 synthesis and proliferation in stimulated human lymphocytes. The results suggest a possible link between activation of PKC-beta and regulation of IL-2 synthesis in activated human lymphocytes. Thus, inhibition of the activation and translocation of PKC-beta by CsA may result in inhibition of IL-2 gene expression in human lymphocytes.

Restoration of exocytosis occurs after inactivation of intracellular tetanus toxin.

Tetanus toxin blocks carbachol-stimulated release of noradrenaline from bovine adrenal chromaffin cells in culture, provided it can gain access to the cells. This can be achieved by electropermeabilization of the plasma membrane or by enriching the membrane with exogenous gangliosides which serve as carriers of the toxin. The inhibition of noradrenaline release persists for at least 6 days, even in the presence of specific anti-tetanus toxin antibodies in the culture medium. However, the block is preventable, for the most part, when antibodies enter chromaffin cells during electropermeabilization, before the uptake of the toxin is facilitated by inserting exogenous gangliosides into the plasma membrane 2 days later. This indicates that the antibodies pass into the cells through the physically induced pores and that these intracellular antibodies neutralize incoming tetanus toxin. If, on the other hand, exocytosis has been inhibited by tetanus toxin, it will recover within 3 days, provided specific anti-tetanus toxin antibodies are introduced into the cells by electropermeabilization. The recovery is not linked to a specific route of entry of the toxin. It is concluded that the restoration of noradrenaline release requires not only the intracellular neutralization of tetanus toxin but also the reconstitution of the as yet unknown target molecule of the toxin.

Distinct targets for tetanus and botulinum A neurotoxins within the signal transducing pathway in chromaffin cells.

Tetanus and botulinum A neurotoxins inhibited exocytosis evoked by various secretagogues in intact and permeabilized chromaffin cells. The block of exocytosis in intact chromaffin cells due to botulinum A neurotoxin could partially be overcome by enhancing nicotine- and veratridine-induced stimulation, whereas the block due to tetanus toxin persisted under the same conditions. The receptor-mediated restoration of 3H-noradrenaline release was specific for nicotinic stimulation, because exocytosis did not occur during muscarinic stimulation. Depolarization of intact chromaffin cells with increasing concentration of K+ failed to restore exocytosis that had been blocked by either toxin. When chromaffin cells, treated with tetanus or botulinum A neurotoxins, were exposed to the Ca2(+)-ionophore A 23187 or permeabilized by staphylococcal alpha-toxin, Ca2(+)-stimulated exocytosis was also inhibited. The inhibition was unaffected by increasing concentrations of free Ca2+. Activation of proteinkinase C and of G-proteins by phorbolester and GMPPNHP, respectively, increased Ca2(+)-induced exocytosis in control cells as well as in cells treated with tetanus and botulinum A neurotoxins. The block, however, could not be relieved by these manipulations, and it could not be relieved by activating the cGMP or cAMP pathways with analoga of cyclic nucleotides, phosphodiesterases inhibitors, and forskolin either. It is concluded that nicotine and veratridine trigger a mechanism within the sequence of events leading to exocytosis that is located beyond the increase in intracellular Ca2(+)-concentration. This pathway may not be affected by botulinum A neurotoxin. The target of tetanus toxin is probably located even closer to the fusion process, i.e. beyond the step upon which botulinum A neurotoxin acts.

[Peripheral vein requirement-adjusted parenteral feeding: renaissance of maltose?]. / Peripher-venöse bedarfsadaptierte parenterale Ernährung: Renaissance der Maltose?

A requirement-adapted peripheral-venous parenteral nutrition was developed by exchanging the conventional carbohydrates like glucose, etc., for disaccharide maltose in combination with a fat emulsion (650 mosm/l; 2,000 kcal). In a clinical randomised study, we compared this nutrition regimen with a common requirement-adapted parenteral nutrition regimen, which was applicated by central-venous catheter (2,000 mosm/l; 2,000 kcal). All results, including the results of tracer-investigations with the strable isotope 13C-leucine, showed no metabolic difference between these two nutrition regimens.

Clinical evaluation of diagnostic hemoperfusion for in vivo enrichment of bacteria and fungi in comparison with a conventional blood culture technique.

The hemoperfusion module, a newly developed technique for recovering pathogenic microorganisms from patients suffering from septicemia, was compared with conventional blood cultures. The module was interconnected with the extracorporeal circulation of 92 predominantly hemodialyzed patients. Nearly 12 liters of flowing blood (up to 200 ml min-1; mean running time, 60 min) came in contact with the coated charcoal. Of 99 modules examined, 44 (44.7%) yielded positive cultures and contained 54 potentially pathogenic bacteria or fungi (22 species). Only 32 of 190 (16.8%) conventional blood cultures were positive and contained 37 microorganisms (10 species). Even when patients were receiving antibiotic treatment, the frequency of isolation was significantly higher in hemoperfusion (21 of 44 modules positive, 47.7%) than in conventional blood cultures (10 of 88 cultures positive, 11.4%). In contrast, 23 of 55 modules (41.8%) and 22 of 102 conventional blood cultures (21.6%) were positive when patients were not treated with antibiotics prior to blood sampling. Altogether, hemoperfusion modules appeared to be superior to and more sensitive than the conventional blood cultures used and seemed to be a valuable tool for detecting septicemia.

Dominance of one T-cell receptor in the H-2Kb/TNP response.

T-cell receptors (TCRs) recognize foreign antigens in the context of major histocompatibility complex (MHC)-encoded cell surface proteins. These receptors are heterogeneous, dimeric glycoproteins composed of disulphide linked alpha- and beta-chains. We analysed the diversity of TCRs in a collection of H-2Kb-restricted, 2,4,6-trinitrophenyl (TNP)-specific (H-2Kb/TNP) cytotoxic T-cell (Tc) clones from C57BL/6 mice. Investigation of the beta-chain messenger RNAs revealed that nearly half of these independent clones expressed an identical beta-chain gene. We show here that almost all the Tc clones expressing the predominant beta-chain gene also express an identical alpha-chain gene. These results show that a strong selective pressure acted on the Tc population, resulting in a skewing of the TCR repertoire for H-2Kb/TNP and in the dominant expression of one TCR with this specificity. Possible explanations for this skewing include antigen-driven clonal expansion and network interactions.