Specific inhibition of interleukin-13 activity by a recombinant human single-chain immunoglobulin domain directed against the IL-13 receptor alpha1 chain

Interleukin-13 (IL-13) is a T-cell-derived pleiotropic cytokine of particular medical importance because of its critical role in the development of allergic asthma. The effects of IL-13 on its target cells are mediated through a dimeric transmembrane receptor (IL-13R), which shares the IL-4Ralpha subunit with the IL-4R system, but contains as a specific component the IL-13Ralpha1 chain. We have generated a set of single-chain Fv fragments with specific binding capacity to the extracellular domain of the human IL-13Ralpha1 receptor. Bacteriophage clones displaying receptor-binding antibody domains were selected from both naive and synthetic libraries by repetitive panning on recombinant and cell surface-expressed recombinant IL-13Ralpha1. Their specific reactivity with native human IL-13Ralpha1 expressed on the surface of transfected cells was demonstrated by flow cytometry. One binder that specifically interfered with cell activation by IL-13 was extensively characterized. This scFv inhibited IL-13-driven gene transcription and cell proliferation in test cell lines, as well as IL-13-induced activation of primary human monocytes in a dose-dependent manner, with an IC(50) below 300 nM. This novel reagent thus constitutes a valuable tool for the further elucidation of IL-13 function in disease and offers potential therapeutic perspectives.

Semantic interoperability--HL7 Version 3 compared to advanced architecture standards

OBJECTIVES

To meet the challenge for high quality and efficient care, highly specialized and distributed healthcare establishments have to communicate and co-operate in a semantically interoperable way. Information and communication technology must be open, flexible, scalable, knowledge-based and service-oriented as well as secure and safe.

METHODS

For enabling semantic interoperability, a unified process for defining and implementing the architecture, i.e. structure and functions of the cooperating systems' components, as well as the approach for knowledge representation, i.e. the used information and its interpretation, algorithms, etc. have to be defined in a harmonized way. Deploying the Generic Component Model, systems and their components, underlying concepts and applied constraints must be formally modeled, strictly separating platform-independent from platform-specific models.

RESULTS

As HL7 Version 3 claims to represent the most successful standard for semantic interoperability, HL7 has been analyzed regarding the requirements for model-driven, service-oriented design of semantic interoperable information systems, thereby moving from a communication to an architecture paradigm. The approach is compared with advanced architectural approaches for information systems such as OMG's CORBA 3 or EHR systems such as GEHR/openEHR and CEN EN 13606 Electronic Health Record Communication.

CONCLUSION

HL7 Version 3 is maturing towards an architectural approach for semantic interoperability. Despite current differences, there is a close collaboration between the teams involved guaranteeing a convergence between competing approaches.

Renal response to acute acid loading--an organ physiological approach

OBJECTIVE

In previous studies of the renal response to acute NH4Cl acidosis no correlation was found between systemic acid-base status and the traditionally used quantity, renal net acid excretion (NAE). If NAE is to be considered a physiologically meaningful quantity then this is surprising, as the extracellular acid-base status would be expected to be the key physiological trigger for renal NAE. The object of this study was to investigate the renal response to acute non-carbonic acid loading using a quantitative organ physiological approach.

MATERIAL AND METHODS

Five-h NH4Cl loading studies were performed in 10 healthy men using a randomized, placebo-controlled, crossover design. Arterialized capillary blood, serum and urine were collected hourly during the loading studies for the measurement of electrolytes and acid-base status. Concentrations of non-metabolizable base (NB) and acid (NA) were calculated from measured concentrations of non-metabolizable ions according to Kildeberg.

RESULTS

In the steady state (placebo) the rate of renal excretion of NA (=-NB) was close to zero, indicating that the net extrarenal input of NA (endogeneous production, gastrointestinal absorption. skeletal release, etc.) was likewise about zero. An inverse correlation was found between blood pH and the rate of renal excretion of NA. Only a small amount of the acid load (approximately 8%) was excreted during the 5-h study period and this was accompanied by massive calciuria, indicating that mobilization of NB from bone contributed substantially to the current net extrarenal NA input.

CONCLUSION

From a physiological point of view, NB can be regarded as the actual substrate for renal acid-base control, and measurement of renal turnover of NB may give a more precise description of renal acid-base metabolism during acid loading than previously described methods.

Plasma glutamine and glutamate concentrations in Gabonese children with Plasmodium falciparum infection

BACKGROUND

Low plasma glutamine levels in critical illness, neonates and burns patients are associated with poor outcome and increased risk of intercurrent infection.

AIM

To investigate the relationship between plasma glutamine/glutamate levels and severity/outcome of malaria.

DESIGN

Two-hospital prospective study, with both febrile and healthy controls.

METHODS

We measured plasma glutamine and glutamate concentrations in 239 Gabonese patients: 145 children with malaria (86 with severe, 36 with moderate and 23 with uncomplicated disease), 42 healthy children, 44 febrile controls and eight healthy adults, and related findings to conventional markers of disease severity such as plasma lactate.

RESULTS

Median (IQR) plasma glutamine was lower in uncomplicated falciparum malaria and in moderate malaria than in healthy controls: 353 (287-474) and 379 (293-448) vs. 485 (428-531) micromol/l, respectively; p<0.01 for both malaria groups vs. controls. In contrast, plasma glutamine was within the normal range in those with severe malaria and in febrile control children: 431 (342-525) and 472 (338-547) micromol/l, respectively. Furthermore, plasma glutamine was significantly higher in the children who died with malaria than in survivors: 514 (374-813) (n=12) vs. 399 (316-475) micromol/l (n=133), respectively; p=0.001. There were no significant differences in plasma glutamate concentrations between any of the study groups.

DISCUSSION

In severe malaria, there was a positive correlation between plasma glutamine and lactate levels (p=0.009, r=0.281). This correlation may reflect impaired gluconeogenesis. Glutamine supplementation is probably not justified in severe P. falciparum infection.

Securing interoperability between chip card based medical information systems and health networks

Health information systems supporting shared care are going to be distributed and interoperable. Dealing with sensitive personal medical information, such information systems have to provide appropriate security services, allowing only authorised users restricted access rights to the patients' data according to the 'need to know' principle. Especially in healthcare, chip card based information systems occur in the shape of patient data cards providing informational self determination and mobility of the users as well as quality, integrity, accountability, and availability of the data stored on the card, thus improving the shared care of patients. The DIABCARD project aims at the implementation and evaluation of a chip card based medical information system (CCMIS) for facilitating communication and co-operation between health professionals in different organisations or departments caring the same patient with diabetes as an example. In co-operation with the EC-funded TrustHealth(2) project, communication and application security services needed are provided like strong authentication as well as the derived services such as authorisation, access control, accountability, confidentiality, etc. The solution is based on Health Professional Cards and Trusted Third Party services. In addition to the secure handling of the patient's chip card and data in DIABCARD workstations, the secure communication between these workstations and related departmental systems has been implemented. Based on the results of this feasibility study, an enhanced security services specification for the DIABCARD example of a CCMIS is provided which will be implemented in the framework of a health network being established in the German federal state Bavaria. Beside the preferred solution of a combination of Patient Identification Card and Patient Data Card, lower level alternatives using card-verifiable certificates are explained in some details. Finally, a few legal issues, future trends like the XML standard set and their implications for the solution presented as well as for distributed health information systems in general are shortly discussed.

Local and remote visualization techniques for interactive direct volume rendering in neuroradiology

The increasing capabilities of magnetic resonance (MR) imaging and multisection spiral computed tomography (CT) to acquire volumetric data with near-isotropic voxels make three-dimensional (3D) postprocessing a necessity, especially in studies of complex structures like intracranial vessels. Since most modern CT and MR imagers provide limited postprocessing capabilities, 3D visualization with interactive direct volume rendering requires expensive graphics workstations that are not available at many institutions. An approach has been developed that combines fast visualization on a low-cost PC system with high-quality visualization on a high-end graphics workstation that is directly accessed and remotely controlled from the PC environment via the Internet by using a Java client. For comparison of quality, both techniques were applied to several neuroradiologic studies: visualization of structures related to the inner ear, intracranial aneurysms, and the brainstem and surrounding neurovascular structures. The results of pure PC-based visualization were comparable with those of many commercially available volume-rendering systems. In addition, the high-end graphics workstation with 3D texture-mapping capabilities provides visualization results of the highest quality. Combining local and remote 3D visualization allows even small radiologic institutions to achieve low-cost but high-quality 3D visualization of volumetric data.

Comparison of methods for the rapid laboratory assessment of children with malaria

Rapid diagnosis and accurate quantification of Plasmodium falciparum parasitemia are important for the management of malaria. The assessment of disease severity also depends on evaluation of metabolic indexes such as blood glucose and lactate concentrations. Here we describe an accurate and rapid alternative to conventional thick film examination (Lambaréné method). We also assess near-patient methods for measuring blood glucose (OneTouch) and lactate (Accusport). The accuracy of the Lambaréné method is similar to that of thin films. Results from the OneTouch glucose meter also are in good agreement with a YSI 2300 reference meter. Overall, the Accusport lactate meter agrees poorly with the YSI 2300 reference meter. However, the sensitivity and specificity to detect hyperlactatemia (blood lactate > or = 5 mmol/L) are 0.94 and 0.98, respectively.

Expression of the gap junction connexins Cx43, Cx45 and Cx26 in human uterine leiomyomata

Uterine leiomyomata of 34 premenopausal women undergoing leiomyomectomy or hysterectomy, and in four cases the corresponding myometrium, were collected at laparotomy or laparoscopy to investigate the ability of these benign smooth muscle cell tumors to express different connexins. Immunohistochemical and Northern blot analyses were performed for the characterization of the expression of connexins Cx43, Cx45, Cx26 and Cx32. Immunofluorescence revealed the presence of Cx43 in most leiomyomata. Only seven leiomyomata lacked Cx43 expression. Cx45 was expressed in 13, a weak Cx26 immunostaining was found in seven cases, whereas Cx32 could not be detected. No correlations between the 17 beta-estradiol or progesterone serum levels and the expression patterns of the connexins Cx43, Cx45 and Cx26 could be observed. Gonadotropin-releasing hormone (GnRH)-agonist or progestin treatment did not influence the connexin expression pattern. Northern blot analyses confirmed these results; however, transcripts of Cx26 were not detectable. Connexin transcripts between myomata and the corresponding myometrium showed no obvious differences. Our data show that uterine leiomyomata are capable of expressing different connexins comparable to the corresponding myometrium, but do not respond to different hormonal conditions. The ability to express the appropriate connexins could explain why these tumors, though developing independently of hormonal levels, are still differentiated benign smooth muscle tumors.

Secure interoperability of patient data cards in health networks

In the healthcare area, chip card based information systems occur in the shape of patient data cards providing informational self determination and mobility of the users as well as quality, integrity, accountability, and availability of the data stored on the card, thus improving the shared care of patients. Dealing with sensitive personal medical information, shared care information systems have to provide appropriate security services, only authorized users allowing restricted rights to the patients' data according to the "need to know" principle. The DIABCARD project aims the implementation and evaluation of a chip card based medical information system (CCMIS) for facilitating communication and co-operation between health professionals in different organisations or departments caring the same patient with Diabetes as an example. In co-operation with the EC-funded TrustHealth project, the communication and application security services needed are provided as strong authentication and the derived services like authorization, access control, accountability, confidentiality etc. The solution is based on Health Professional Cards and Trusted Third Party services. Besides the secure handling of the patient's chip cart in DIABCARD workstations, also the secure communication between these workstations and related departmental systems has been implemented. Finally, a few legal issues, future trends like the XML standard set and their implications for the solution presented as well as for distributed health information systems in general are shortly discussed.

Enhanced security services for enabling pan-European healthcare networks

Establishing the Shared Care environment, communication and co-operation between healthcare establishments involved must be provided in a trustworthy way. This challenge is even more important for health networks using the Internet. In that context, services assuring both communication security and application security must be provided. Especially in the e-health environment, additionally to identity-related services certifying data or properties of principals, trustworthiness or authorisation for objects, components and functions must be established by Trusted Third Parties (TTP). Within the European Commission's Information Society Technologies (IST) Programme, the HARP project provides the "HARP Cross-Security Platform (HCSP)" needed in the open Web environment of pan-European networks. The solutions are under implementation and evaluation in the German ONCONET enabling a trustworthy framework for both health professionals and patients as well as supporting clinical studies.

E- and P-selectin expression in endometriotic tissues and the corresponding endometria

Endometriosis is one of the most frequent diseases in gynecology. It is histologically defined as a non-malignant pathology in which endometrial-like tissue is found outside the uterus. The pathogenesis and mechanisms involved in the development of endometriosis-associated pain symptoms are still under investigation. A local peritoneal inflammation seems to play an important role in the origin of these symptoms. Selectins belong to a group of cell adhesion molecules that mediate the localization of circulating leukocytes on the endothelium at the sites of inflammation. The aim of this study was to investigate the expression of E- and P-selectins in endometriotic tissues and the corresponding endometria. Thirty endometriotic samples, 13 corresponding endometria and six endometria of patients without endometriosis were analyzed using an immunohistochemical technique. Just two endometriotic tissues expressed E-selectin, while five samples were positive for P-selectin. The selectin expression of the corresponding endometria was also very weak. No correlations between the revised American Fertility Society (rAFS) score or the hormonal situation of the patients at the time of biopsy and the selectin expression could be found. In conclusion, the selectin expression in endometriotic glands does not play an important role in the initiation of inflammatory processes caused by endometriosis. This inflammation must be considered as a secondary reaction after the implantation of the endometriotic glands, so that endometriotic tissues are not able to induce, by the expression of selectins, a direct inflammation.

Communication security in open health care networks

Fulfilling the shared care paradigm, health care networks providing open systems' interoperability in health care are needed. Such communicating and co-operating health information systems, dealing with sensitive personal medical information across organisational, regional, national or even international boundaries, require appropriate security solutions. Based on the generic security model, within the European MEDSEC project an open approach for secure EDI like HL7, EDIFACT, XDT or XML has been developed. The consideration includes both securing the message in an unsecure network and the transport of the unprotected information via secure channels (SSL, TLS etc.). Regarding EDI, an open and widely usable security solution has been specified and practically implemented for the examples of secure mailing and secure file transfer (FTP) via wrapping the sensitive information expressed by the corresponding protocols. The results are currently prepared for standardisation.

MAPKAP kinase 2 phosphorylates serum response factor in vitro and in vivo

Several growth factor- and calcium-regulated kinases such as pp90(rsk) or CaM kinase IV can phosphorylate the transcription factor serum response factor (SRF) at serine 103 (Ser-103). However, it is unknown whether stress-regulated kinases can also phosphorylate SRF. We show that treatment of cells with anisomycin, arsenite, sodium fluoride, or tetrafluoroaluminate induces phosphorylation of SRF at Ser-103 in both HeLa and NIH3T3 cells. This phosphorylation is dependent on the kinase p38/SAPK2 and correlates with the activation of MAPKAP kinase 2 (MK2). MK2 phosphorylates SRF in vitro at Ser-103 with similar efficiency as the small heat shock protein Hsp25 and significantly better than CREB. Comparison of wild type murine fibroblasts with those derived from MK2-deficient mice (Mk(-/-)) reveals MK2 as the major SRF kinase induced by arsenite. These results demonstrate that SRF is targeted by several signal transduction pathways within cells and establishes SRF as a nuclear target for MAPKAP kinase 2.

Leptomycin B-sensitive nuclear export of MAPKAP kinase 2 is regulated by phosphorylation

To study the intracellular localization of MAPKAP kinase 2 (MK2), which carries a putative bipartite nuclear localization signal (NLS), we constructed a green fluorescent protein-MAPKAP kinase 2 fusion protein (GFP-MK2). In transfected cells, this protein is located predominantly in the nucleus; unexpectedly, upon stress, it rapidly translocates to the cytoplasm. This translocation can be blocked by the p38 MAP kinase inhibitor SB203580, indicating its regulation by phosphorylation. Molecular mimicry of MK2 phosphorylation at T317 in GFP-MK2 led to a mutant which is located almost exclusively in the cytoplasm of the cell, whereas the mutant T317A shows no stress-induced redistribution. Since leptomycin B, which inhibits the interaction of exportin 1 with the Rev-type leucine-rich nuclear export signal (NES), blocks stress-dependent translocation of GFP-MK2, it is supposed that phosphorylation-induced export of the protein causes the translocation. We have identified the region responsible for nuclear export in MK2 which is partially overlapping with and C-terminal to the autoinhibitory motif. This region contains a cluster of hydrophobic amino acids in the characteristic spacing of a leucine-rich Rev-type NES which is necessary to direct GFP-MK2 to the cytoplasm. However, unlike the Rev-type NES, this region alone is not sufficient for nuclear export. The data obtained indicate that MK2 contains a constitutively active NLS and a stress-regulated signal for nuclear export.

KEYWORDS

nuclear export/nuclear import/protein phosphorylation/signal transduction/stress response

PMA-induced activation of the p42/44ERK- and p38RK-MAP kinase cascades in HL-60 cells is PKC dependent but not essential for differentiation to the macrophage-like phenotype

The signaling mechanisms leading to phorbol ester myristate (PMA)-induced differentiation of HL-60 cells to the macrophagelike phenotype were investigated by using different protein kinase inhibitors. The protein kinase C inhibitor Ro 31-8220 specifically blocks PMA-induced differentiation, activation of the p42/44ERK- and p38RK-MAP kinase cascades and Hsp27-phosphorylation in HL-60 cells. Because Ro 31-8220 does not inhibit activation of the MAP kinase cascades by protein kinase C (PKC)-independent signals such as epidermal growth factor (EGF), heat shock, or anisomycin in these cells, only PMA-induced activation of the MAP kinases can be downstream of PKC. The MEK1 inhibitor PD 098059 and the p38RK inhibitor SB 203580 also were used to analyze whether the PMA-induced PKC-dependent activation of MAP kinases is involved in the differentiation process. Under certain conditions, PD 098059 can completely block the PMA-induced activation of the p42ERK as monitored by immunoprecipitation kinase assay by using the substrate myelin basic protein. SB 203580 specifically inhibits activation of p38RK as judged by MAPKAP kinase 2 activity against the substrate Hsp27 and also blocks Hsp27 phosphorylation in the cells. In contrast, neither PD 098059 nor SB 203580 nor both inhibitors together prevent PMA-induced differentiation of the HL-60 cells to the macrophagelike phenotype. The results suggest the existence of a diversification of PMA-induced signaling in HL-60 cells downstream of PKC, leading to activation of MAP kinases that are not essential for differentiation and to phosphorylation of other, so far unidentified, targets responsible for differentiation.

Optical properties of deep ice at the South Pole: absorption

We discuss recent measurements of the wavelength-dependent absorption coefficients in deep South Pole ice. The method uses transit-time distributions of pulses from a variable-frequency laser sent between emitters and receivers embedded in the ice. At depths of 800-1000 m scattering is dominated by residual air bubbles, whereas absorption occurs both in ice itself and in insoluble impurities. The absorption coefficient increases approximately exponentially with wavelength in the measured interval 410-610 nm. At the shortest wavelength our value is approximately a factor 20 below previous values obtained for laboratory ice and lake ice; with increasing wavelength the discrepancy with previous measurements decreases. At ~415 to ~500 nm the experimental uncertainties are small enough for us to resolve an extrinsic contribution to absorption in ice: submicrometer dust particles contribute by an amount that increases with depth and corresponds well with the expected increase seen near the Last Glacial Maximum in Vostok and Dome C ice cores. The laser pulse method allows remote mapping of gross structure in dust concentration as a function of depth in glacial ice.

CREB is activated by UVC through a p38/HOG-1-dependent protein kinase

Changes in environmental conditions such as the addition of growth factors or irradiation of cells in culture first affect immediate response genes. We have shown previously that short wavelength UV irradiation (UVC) elicits massive activation of several growth factor receptor-dependent pathways. At the level of the immediate response gene c-fos, these pathways activate the transcription factor complex serum response factor (SRF)-p62TCF which mediates part of the UV-induced transcriptional response. These studies have, however, suggested that more that one pathway is required for full UV responsiveness of c-fos. Using appropriate promoter mutations and dominant-negative cAMP response element (CRE)-binding protein (CREB), we now find that UVC-induced transcriptional activation depends also on the CRE at position -60 of the c-fos promoter and on the functionality of a CREB. Upon UV irradiation, CREB and ATF-1 are phosphorylated at serines 133 and 63, respectively, preceded by and dependent on activation of p38/RK/HOG-1 and of a p38/RK/HOG-1-dependent p108 CREB kinase. Although p90RSK1 and MAPKAP kinase 2 are also activated by UV, p90RSK1 does not, at least not decisively, participate in this signalling pathway to CREB and ATF-1 as it is not p38/RK/HOG-1 dependent, and CREB is a poor substrate for MAPKAP kinase 2 in vitro. On the basis of resistance to the growth factor receptor inhibitor suramin and of several types of cross-refractoriness experiments, the UVC-induced CREB/ATF-1 phosphorylation represents an as yet unrecognized route of UVC-induced signal transduction, independent of suramin-inhibitable growth factor receptors and different from the Erk 1,2-p62TCF pathway.

The protein kinase inhibitor SB203580 uncouples PMA-induced differentiation of HL-60 cells from phosphorylation of Hsp27

HL-60 cells are an attractive model for studies of human myeloid cell differentiation. Among the well-examined parameters correlated to differentiation of HL-60 cells are the expression and phosphorylation of the small heat shock protein Hsp27. Here we demonstrate that PMA treatment of HL-60 cells stimulates different MAP kinase cascades, leading to significant activation of ERK2 and p38 reactivating kinase (p38RK). Using the protein kinase inhibitor SB 203580, we specifically inhibited p38RK and, thereby, activation of its target MAP kinase-activated protein kinase 2 (MAPKAP kinase 2), which is the major enzyme responsible for small Hsp phosphorylation. As a result, PMA-induced Hsp27 phosphorylation is inhibited in SB 203580-treated HL-60 cells indicating that p38RK and MAPKAP kinase 2 are components of the PMA-induced signal transduction pathway leading to Hsp27 phosphorylation. We further demonstrate that, although PMA-induced phosphorylation is inhibited, SB 203580-treated HL-60 cells are still able to differentiate to the macrophage-like phenotype as judged by decrease in cell proliferation, induction of expression of the cell surface antigen CD11b and changes in cell morphology. These results indicate that, although correlated, Hsp27 phosphorylation is not required for HL-60 cell differentiation. However, the results do not exclude that increased Hsp27 expression is involved in HL-60 cell differentiation.