End-tidal control vs. manually controlled minimal-flow anesthesia: a prospective comparative trial.

BACKGROUND: To ensure safe general anesthesia, manually controlled anesthesia requires constant monitoring and numerous manual adjustments of the gas dosage, especially for low- and minimal-flow anesthesia. Oxygen flow-rate and administration of volatile anesthetics can also be controlled automatically by anesthesia machines using the end-tidal control technique, which ensures constant end-tidal concentrations of oxygen and anesthetic gas via feedback and continuous adjustment mechanisms. We investigated the hypothesis that end-tidal control is superior to manually controlled minimal-flow anesthesia (0.5 l/min). METHODS: In this prospective trial, we included 64 patients undergoing elective surgery under general anesthesia. We analyzed the precision of maintenance of the sevoflurane concentration (1.2-1.4%) and expiratory oxygen (35-40%) and the number of necessary adjustments. RESULTS: Target-concentrations of sevoflurane and oxygen were maintained at more stable levels with the use of end-tidal control (during the first 15 min 28% vs. 51% and from 15 to 60 min 1% vs. 19% deviation from sevoflurane target, P < 0.0001; 45% vs. 86% and 5% vs. 15% deviation from O2 target, P < 0.01, respectively), while manual controlled minimal-flow anesthesia required more interventions to maintain the defined target ranges of sevoflurane (8, IQR 6-12) and end-tidal oxygen (5, IQR 3-6). The target-concentrations were reached earlier with the use of end-tidal compared with manual controlled minimal-flow anesthesia but required slightly greater use of anesthetic agents (6.9 vs. 6.0 ml/h). CONCLUSIONS: End-tidal control is a superior technique for setting and maintaining oxygen and anesthetic gas concentrations in a stable and rapid manner compared with manual control. Consequently, end-tidal control can effectively support the anesthetist.

Safety and efficacy of healthy volunteer stem cell mobilization with filgrastim G-CSF and mobilized stem cell apheresis: results of a prospective longitudinal 5-year follow-up study.

BACKGROUND AND OBJECTIVES: G-CSF-mobilized peripheral blood stem cells have long replaced marrow as the major source for allogeneic transplants. Conclusive evidence questioning the long-term safety of G-CSF for donors has not been provided, but the cumulative number of followed donors remains insufficient to rule out rare adverse events. A long-term active follow-up study of G-CSF-mobilized healthy volunteer donors was therefore performed. PATIENTS AND METHODS: Two hundred and three successive donors were evaluated pre-apheresis, subjected to G-CSF-mobilization/apheresis, and actively followed for 5 years by the same physicians and laboratories. Follow-up laboratory work included standard biochemical/haematological tests and T-cell phenotyping. RESULTS: Donor epidemiology was typical for reported stem cell donor cohorts. Acute adverse effects of G-CSF and apheresis were mild and transient, consistent with the previous reports. Mean circulating CD34(+) cells after nine doses of G-CSF were 124 per µl. Other biochemical/haematological parameters were also altered, consistent with G-CSF treatment. Spleen enlargement was modest. At first follow-up, all clinical and laboratory parameters had normalized. Leucocyte/lymphocyte counts and CD4/CD8 ratios were the same as during premobilization work-up and remained unchanged throughout. A single severe but likely unrelated adverse event, a case of papillary thyroid carcinoma, was reported. CONCLUSION: The studies add an observation time of almost 500 donor years to the growing body of evidence of the long-term safety of G-CSF for allogeneic donor stem cell mobilization.

Oxygen measurements in platelet fluids - a new non-invasive method to detect bacterial contaminations in platelets.

BACKGROUND: The residual risk for bacterial contamination in blood components especially in platelets is one to two orders of magnitude higher than for transfusion relevant viral infections. The majority of all bacterial transmitted fatalities occurred at the end of platelet shelf life. Therefore, the maximum shelf life of platelet concentrates (PC) was reduced to 4 days after blood donation in Germany in 2008. METHODS: A new continuous non-invasive bacterial detection method was developed by O(2) measurements in the platelet fluids and tested with 10 transfusion relevant bacteria species. RESULTS: The bacterial concentration at the time point of a positive signal of PreSense O(2) ranged between 10(2) and 10(5) CFU mL(-1) . Harmful transfusion-transmitted bacterial infection would have probably been prevented by this novel technology. Only strict anaerobic bacteria strains like Clostridium perfringens were not detected within the study period of 72 h. CONCLUSIONS: The described non-invasive bacterial detection method represents a new approach to prevent transmission of bacterial infection in platelets. The method is characterised by the advantage that all investigations can be performed until right up to the time of transfusion, and therefore, reduce the risk for sample errors to a minimum.

How much blood is needed?

Demographic changes in developed countries as their populations age lead to a steady increase in the consumption of standard blood components. Complex therapeutic procedures like haematopoietic stem cell transplantation, cardiovascular surgery and solid organ transplantation are options for an increasing proportion of older patients nowadays. This trend is likely to continue in coming years. On the other hand, novel aspects in transplant regimens, therapies for malignant diseases, surgical procedures and perioperative patient management have led to a moderate decrease in blood product consumption per individual procedure. The ageing of populations in developed countries, intra-society changes in the attitude towards blood donation as an important altruistic behaviour and the overall alterations in our societies will lead to a decline in regular blood donations over the next decades in many developed countries. Artificial blood substitutes or in vitro stem cell-derived blood components might also become alternatives in the future. However, such substitutes are still in early stages of development and will therefore probably not alleviate this problem within the next few years. Taken together, a declining donation rate and an increase in the consumption of blood components require novel approaches on both sides of the blood supply chain. Different blood donor groups require specific approaches and, for example, inactive or deferred donors must be re-activated. Optimal use of blood components requires even more attention.

Blood transfusion in Europe: basic principles for initial and continuous training in transfusion medicine: an approach to an European harmonisation.

Over the past few decades, transfusion medicine and haemotherapy have evolved into complex medical disciplines comprising a broad field of subspecialties such as immunohaematology, blood component production, haemapheresis and haemostaseology. Transfusion medicine is thus an important qualification at the interfaces of analytical laboratory medicine, pharmaceutical production and clinical disciplines such as internal medicine, anaesthesiology or surgery. Physicians specialising in transfusion medicine are valuable and competent partners for these related disciplines when it comes to safe, effective and tailored haemotherapy. Why has transfusion medicine become so complex? On the one hand, one can discern problems such as infectious diseases like the HIV disaster in the past century, resulting in guidelines, directives and laws such as the transfusion law in Germany. Thereby, we now enjoy the highest level of blood product safety ever regarding viral transmission thanks to the broad implementation of PCR testing. On the other hand, there are numerous positive reasons for the increasing complexity of transfusion medicine: Modern medical therapies like stem cell transplantation, cellular therapy, transplantation of solid organs, regenerative medicine and surgery cannot exist without a safe supply of blood products and high quality standard as well as special blood products and laboratory services provided by blood banks and transfusion medicine specialists. Good laboratory practice (GLP), good manufacturing practice (GMP), quality management systems and quality control on the pharmaceutical manufacturer's level are only few examples of the standards in today's blood banking. European directives in the field of blood products, stem cell preparations and tissue have led to higher uniform quality standards for biological preparations in a unified Europe, which is the desired outcome, but which also increases the complexity of this field. In contrast, directives 93/16/EEC and 2001/19/EC, the directives of the European Parliament and of the Council on the mutual recognition of professional qualifications of European doctors currently in force, as well as the impending directive 2005/36/EC, which has to be translated into national law until October 2007, do not include transfusion medicine, blood transfusion or immunohaematology at all. Other medical specialities, which like our field, are not common to all member states of the European Union, are listed in the above mentioned directives with the minimum length of training and minimal requirements for the qualifications. Examples include clinical biology, biological haematology, microbiology-bacteriology, biological chemistry, immunology, thoracic, paediatric or vascular surgery as well as physiotherapy, stomatology, neuro-psychiatry, dermato-venerology, occupational medicine, allergology, geriatrics, gastro-enterological surgery, community medicine, nuclear medicine, pharmacology, accident and emergency medicine or tropical medicine. Most of the above are medical specialities in some member states, but not in all. A concerted initiative inaugurated by the European Network of Transfusion Medicine Societies (EuroNet-TMS) and the European Blood Alliance (EBA) aims to compile the situation of the transfusion medicine speciality throughout Europe. A preliminary summary of the current situation in 15 European states was prepared in 2005 after a first set of questions, which was sent out by us via the EBA platform. The authors appreciate Clair Watts' compilation of the answers provided by the 15 European colleagues. A summary of these answers is depicted in Table 1. However, the initiative aims at a more complex analysis of the different requirements and constituent parts of the qualification in transfusion medicine in different countries. A long-term objective of this initiative might be to introduce the transfusion medicine specialisation into the above mentioned EC directives in order to facilitate mutual recognition of transfusion medicine qualifications throughout Europe.

Soluble factors involved in glioma invasion.

Recent studies using molecular and cellular techniques of the factors regulating the invasion process have revealed a crucial role for a number of growth factors and cytokines. Their function lies on the one hand in the autocrine stimulation of the tumor cells themselves, resulting in the stimulation of protease expression and an enhancement of migratory potential. On the other hand, the growth factors and cytokines seem to play a major role in the paracrine activation of the tumor surrounding stroma. Through stimulation of the strong angiogenic response that is characteristic for gliomas and also of the expression of proteases in the stromal cells, they contribute critically to the generation of a stromal environment that is permissive or even inductive for tumor cell invasion. Understanding of the mechanisms by which soluble factors modulate glioma cell invasion therefore will help to determine targets for the modification of existing therapies and lead to the development of novel therapeutic strategies in the management of gliomas.

Tumor progression of skin carcinoma cells in vivo promoted by clonal selection, mutagenesis, and autocrine growth regulation by granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor.

Tumor microenvironment is crucial for cancer growth and progression as evidenced by reports on the significance of tumor angiogenesis and stromal cells. Using the HaCaT/HaCaT-ras human skin carcinogenesis model, we studied tumor progression from benign tumors to highly malignant squamous cell carcinomas. Progression of tumorigenic HaCaT-ras clones to more aggressive and eventually metastatic phenotypes was reproducibly achieved by their in vivo growth as subcutaneous tumors in nude mice. Their enhanced malignant phenotype was stably maintained in recultured tumor cells that represented, identified by chromosomal analysis, a distinct subpopulation of the parental line. Additional mutagenic effects were apparent in genetic alterations involving chromosomes 11 and 2, and in amplification and overexpression of the H-ras oncogene. Importantly, in vitro clonal selection of benign and malignant cell lines never resulted in late-stage malignant clones, indicating the importance of the in vivo environment in promoting an enhanced malignant phenotype. Independently of their H-ras status, all in vivo-progressed tumor cell lines (five of five) exhibited a constitutive and stable expression of the hematopoietic growth factors granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, which may function as autocrine/paracrine mediators of tumor progression in vivo. Thus, malignant progression favored by the in vivo microenvironment requires both clonal selection of subpopulations adapted to in vivo growth and mutational events leading to stable functional alterations.

Functional assessment of hand flapping in a general education classroom.

A functional assessment of hand flapping exhibited by a 5-year-old boy was conducted in a general education classroom. After a descriptive analysis ruled out several potential variables maintaining hand flapping, an experimental analysis was used to test the hypothesis that teacher-delivered task demands were functionally related to hand flapping. Results of the experimental analysis were used to develop a simple intervention for hand flapping.

Antecedent manipulations in a tangible condition: effects of stimulus preference on aggression.

After a functional analysis indicated that aggression of an 8-year-old boy with autism was maintained by access to preferred items, antecedent manipulations involving the relative preference of restricted and noncontingently available stimuli were conducted. Restricting highly preferred items evoked the highest rates of aggression regardless of the preference level of the noncontingently available alternative items. Restricting less preferred stimuli was associated with moderate rates of aggression even when the alternative items were more preferred.

Effect of mycophenolate mofetil therapy on inosine monophosphate dehydrogenase induction in red blood cells of heart transplant recipients.

BACKGROUND: Mycophenolic acid is reported to provide effective immunosuppression by inhibiting inosine monophosphate dehydrogenase. In an attempt to monitor the biological effects of long-term therapy with mycophenolate mofetil, we measured levels of guanosine 5' triphosphate and adenosine 5' triphosphate in red blood cells (RBCs) of patients after heart transplantations. METHODS: Fifty-two patients enrolled in the study were randomly assigned to one of two groups. Patients in the control group (n = 27) received cyclosporine A (INN, ciclosporin), azathioprine, and prednisone. Patients in the study group (n = 25) were switched from azathioprine to mycophenolate mofetil 3 months after the heart transplantation. Adenosine 5' triphosphate and guanosine 5' triphosphate levels were determined by means of HPLC. The activities of inosine monophosphate dehydrogenase and hypoxanthine-guanine phosphoribosyltransferase, which are responsible for guanine nucleotide formation, were measured in RBCs by radiochemical methods. RESULTS: Adenosine 5' triphosphate levels were unchanged in patients treated with mycophenolate mofetil, whereas those of the control group who received azathioprine (from 142 +/- 26 pmol/10(6) RBCs to 165 +/- 25 pmol/10(6) RBCs; P <.001) increased. As the length of mycophenolate mofetil therapy increased, patients in the study group showed significantly elevated guanosine 5' triphosphate levels (15.6 +/- 6.1 pmol/10(6) RBCs versus 6.6 +/- 2.1 pmol/10(6) RBCs; P <.001) and a 5-fold increase in inosine monophosphate dehydrogenase activity (108.6 +/- 13.3 pmol/mg of protein per hour versus 22.5 +/- 1.7 pmol/mg of protein per hour; P <.001) compared with the control group. In addition, a slight but significant enhancement of hypoxanthine-guanine phosphoribosyltransferase activity was seen in the mycophenolate mofetil group. CONCLUSIONS: Our studies have shown that long-term administration of mycophenolate mofetil is associated with increasing guanosine 5' triphosphate levels in RBCs as the result of an induction of inosine monophosphate dehydrogenase and hypoxanthine-guanine phosphoribosyltransferase activities in erythrocytes.

The uPA/uPA receptor system as a target for tumor therapy.

Invasiveness of a variety of tumors depends on the regulated expression of proteolytic enzymes that degrade the surrounding extracellular matrix and dissociate cell-cell and/or cell-matrix attachments. The tumor cell surface-associated urokinase-type plasminogen activator (uPA) system plays an especially important role in tumor cell invasion and metastasis. It consists of the serine protease uPA, its membrane-bound receptor (uPAR, CD87) and one of the natural inhibitors PAI-1 or PAI-2. There are strong indications based on animal experiments that interference with this system by inhibiting the enzymatic activity of uPA and/or antagonizing its binding to the receptor is of therapeutic relevance. With the recent solution of various X-ray structures of uPA/inhibitor complexes, structural information is available for optimizing existing lead compounds in their affinity and selectivity for uPA. Furthermore, peptide compounds capable of mimicking the structural epitope of uPA responsible for binding to the receptor efficiently antagonize this recognition process. Thus, both approaches prove to be well suited for the design of highly promising drugs in human medicine.

The effectiveness of contingency-specific and contingency-nonspecific prompts in controlling bathroom graffiti.

This study replicates and extends the work of Watson (1996) in which a sign eliminated graffiti when posted on bathroom walls. The present study investigated the effects of three different signs on walls in six men's bathrooms located on a university campus. Posting the signs was followed by the elimination or sharp reduction of graffiti. Removal of the signs was followed by a resurgence of graffiti.

Recombinative generalization of within-syllable units in prereading children.

This study demonstrates recombinative generalization of within-syllable units in prereading children. Three kindergarten children learned to select printed consonant-vowel-consonant words upon hearing the corresponding spoken words. The words were taught in sets; there were six sets, presented consecutively. Within sets, the four words that were taught had overlapping letters, for example, sat, mat, sop, and sug. Tests for recombinative generalization determined whether the children selected novel words with the same components as the trained words (e.g., mop and mug). Two children demonstrated recombinative generalization after one training set, and the 3rd demonstrated it after two training sets. In contrast, 2 other children, who received tests but no training, showed low accuracy across six sets. The 3 experimental children then demonstrated highly accurate printed-word-to-picture matching, and named the majority of the printed words. These findings are a promising step in the development of a computerized instructional technology for reading.

Constitutive expression of G-CSF and GM-CSF in human skin carcinoma cells with functional consequence for tumor progression.

Tumor progression is characterized by an increasing escape of tumor cells from the growth control of their microenvironment, often caused by aberrant expression of growth factors. In the human skin carcinoma model system, based on the HaCaT keratinocyte line, tumor progression to high-grade malignant cells is associated with constitutive expression and secretion of the hematopoietic growth factors G-CSF and GM-CSF in vitro and in vivo. All HaCaT keratinocyte variants express the G-CSF and the GM-CSF receptors at levels comparable to normal keratinocytes. Consequently, they exhibit a stimulation of cell proliferation and migration in culture when treated with these factors. Moreover, both proliferation and migration of the high-grade malignant cells were strongly inhibited by neutralizing antibodies to G-CSF and GM-CSF, respectively. This demonstrates the functional role of these factors in high-grade malignant HaCaT cells through an autocrine mechanism in vitro and implies their significance in tumor progression in vivo. In light of the increasing use of G-CSF and GM-CSF in adjuvant tumor therapy, our data, as well as those discussed for head-and-neck tumors and gliomas, warrant a careful re-evaluation of the clinical application of both factors.

Autocrine growth regulation by granulocyte colony-stimulating factor and granulocyte macrophage colony-stimulating factor in human gliomas with tumor progression.

Granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) and/or their receptors are increasingly detected in solid human tumors, although little is known about their function in tumor growth and invasion. We analyzed RNA and protein expression of both factors and their receptors in 22 human gliomas (WHO grade II, III, and IV) and derived cell cultures. G-CSF, GM-CSF, and/or their receptors were expressed in all tumors and derived cell cultures, but coexpression of both factors and receptors was almost exclusively found in grade IV glioblastomas and thus correlated with advanced tumor stage. The functional significance of G-CSF and GM-CSF as regulators for glioma cells was demonstrated by 1) stimulation of proliferation and migration in tumor cells expressing one or both receptors by the corresponding factor; 2) inhibition of growth and migration of glioma cells expressing G-CSF, GM-CSF, and their receptors by neutralizing antibodies to both factors. These results indicate a significant role for both factors in the autocrine regulation of growth and migration in late-stage malignant gliomas and suggest a shift from paracrine to autocrine regulation with tumor progression. The implication of G-CSF and GM-CSF in glioblastoma growth regulation could make these factors further prognostic indicators and raises questions concerning their use in cancer therapy.

[Functional expression of vascular endothelial growth factor receptor Flt-1 on squamous cell carcinoma of the head and neck]. / Funktionelle Expression des VEGF-Rezeptors Flt-1 auf Plattenepithel- karzinomzellen.

Vascular endothelial growth factor (VEGF) is one of the most potent factors in tumor-induced neoangiogenesis. After binding to its specific receptors KDR and FLT-1 on the endothelial cell surface cell proliferation and migration are stimulated. Recently there has been some evidence for the expression of these receptors on tumor cells. We investigated the protein and mRNA expression of KDR and FLT-1 in native tissues and tumor cell cultures from squamous cell carcinomas of the head and neck (HNSCC) and analyzed their in vitro functional significance for tumor cell proliferation and migration. Apart from the expected expression of VEGF receptors on endothelial cells we observed a tumor cell-specific localization of FLT-1 in 29 tumors and KDR in 16 of 37 tumors analyzed. Functional studies in vitro revealed that the addition of VEGF to HNSCC cells inhibited the proliferation and migration of these cells in a dose-dependent manner. Our data suggest a potential negative regulatory loop for VEGF and FLT1 when tumor cells have an insufficient blood supply.

Azathioprine and 6-mercaptopurine alter the nucleotide balance in endothelial cells.

Graft vascular disease after solid organ transplantation is a main complication that limits long-term survival of the graft. An injury of the endothelium and subsequent vascular response is considered to be responsible for smooth muscle cell hyperplasia with resulting luminal narrowing. What is less certain are the precise steps leading to endothelial injury and subsequent vessel disease. Since the immunosuppressive drug azathioprine is in clinical use due to its antiproliferative effect on lymphocytes, we were interested in how far it exerts effects on the vascular endothelium. Azathioprine and its metabolite 6-mercaptopurine, a potent inhibitor of purine salvage pathway enzymes, dose dependently led to decreased endothelial cell proliferation as well as to decreases in intracellular purine nucleotides adenosine-triphosphate and guanosine-triphosphate. By increasing the formation of the pyrimidine nucleotide uridine-triphosphate within 24 hours, azathioprine and its metabolite altered the endothelial nucleotide balance. Since not only the formation of toxic thio- and methylthiopurines (thio-guanosine-monophosphate, methyl-thio-inosine-monophosphate) was measured, the activity of the enzyme thiopurinemethyltransferase was induced (3.21+/-2.04 U per 10(9) cells, mean+/-SD). These findings indicate that the vascular endothelium plays an active role in the metabolization of the established immunosuppressant azathioprine that then exerts specific toxic effects on endothelial cells.

Expression and functional significance of vascular endothelial growth factor receptors in human tumor cells.

Vascular endothelial growth factor (VEGF) is one of the key factors in tumor neoangiogenesis, acting through its receptors KDR (VEGFR-2) and fit-1 (VEGFR-1) expressed on endothelial cells. Our data demonstrate that VEGFR-1 and to a lesser extent VEGFR-2 are expressed in a number of human tumor tissues and derived cells in culture. VEGFR-1 protein is expressed in 26 of 42 glioma tissues, 22 of which show a coexpression of VEGFR-1 with VEGFR-2; 1 glioma tissue expresses exclusively VEGFR-2. In the derived glioma cell cultures, we found VEGFR-1 mRNA expression in 6 of 11 cultures, with one coexpressing VEGFR-1 and VEGFR-2. Of four established glioma cell lines, two expressed VEGFR-1. In addition VEGFR-1 protein expression was demonstrated in 30 of 37 tumor tissues of squamous cell carcinomas of the head and neck, with VEGFR-2 coexpression in 15 tissues and an expression of VEGFR-2 alone in 1 tissue. Derived tumor cell cultures showed mRNA expression of VEGFR-1 alone in seven of seven cases. Established melanoma cell lines expressed VEGFR-1 mRNA in four of five lines, with VEGFR-2 coexpression in two lines. Concerning the functional significance of VEGF receptor expression, VEGF treatment of VEGFR-1-expressing tumor cells induced the inhibition of cell proliferation by 25 to 55% and the inhibition of tumor cell migration by 29 to 55%. Thus our data indicate that the coexpression of VEGF and VEGFR-1 in tumor cells could have an inhibitory effect on tumor cell proliferation and migration, a mechanism possibly induced as a response to a deficiency in nutrient and oxygen supply.