Osseointegration of dental implants in ectopic engineered bone in three different scaffold materials

The in vivo regeneration of bone flaps might be an alternative to autogenous bone grafting. The first human case of mandibular reconstruction using the greater omentum as a bioreactor was reported in 2016. However, whether engineered bone will support the osseointegration of dental implants has not yet been investigated. In this study, bone tissue engineering was performed in the greater omentum of nine miniature pigs using bone morphogenetic protein 2, bone marrow aspirate, and three different scaffolds: hydroxyapatite, biphasic calcium phosphate (BCP), and titanium. After 8 weeks, two implants were placed in each scaffold; after another 8 weeks, the bone blocks were harvested for radiographic, histological, and histomorphometric analysis. All implants exhibited sufficient primary stability, and the success rate was 100%. The bone-to-implant contact ratios (BICs) were 38.2%, 68.5%, and 42.9%; the inter-thread bone densities were 29.4%, 64.9%, and 33.5%; and the peri-implant bone-scaffold densities were 56.4%, 87.6%, and 68.6% in the hydroxyapatite, BCP, and titanium groups, respectively. The BIC showed a strong correlation (r = 0.76) with the peri-implant bone-scaffold density. This study shows that de novo engineered bone leads to successful osseointegration and therefore may allow implant-based prosthodontic rehabilitation.

[Anterior approach liver resection with the liver hanging maneuver. Technique and indications]

The anterior approach liver resection has advantages compared to conventional liver resection. Mobilization during conventional liver resection may cause local pressure on the tumor which could lead to tumor cell dissemination or even to tumor rupture. Furthermore, hemodynamic parameters tend to deteriorate during mobilization due to compression or twisting of the inferior vena cava. In addition, the left liver lobe often is compressed which can lead to tissue damage of the residual parenchyma. The risk of these complications can be reduced by the anterior approach technique which is facilitated by the so-called liver hanging maneuver. Appropriate indications for this technique are large tumors of the right liver lobe, tumors with infiltration of the right hepatic vein and infiltration of the vena cava from the right side, tumors with infiltration of the diaphragm and tumors of the right lobe after previous resections of the right lobe.

CCL21 (SLC) improves tumor protection by a DNA vaccine in a Her2/neu mouse tumor model

Secondary lymphoid-tissue chemokine (SLC/CCL21) is a CC chemokine that is constitutively expressed in various lymphoid tissues and binds to chemokine receptor CCR7 on mature dendritic cells (DCs) and distinct T-and B-cell sub-populations. In vivo, CCL21 regulates the encounters between DC and T cells and thus is a key regulator of adaptive immune responses. We asked whether CCL21 is able to augment immunogenicity of a DNA-based vaccine against Her2/neu in a Balb/c mouse model with syngeneic Her2/neu+ tumor cells (D2F2/E2). Mice were vaccinated intramuscularly with plasmid DNA (pDNA) on day 1 and boosted on day 15; tumor challenge was performed subcutaneously on day 25. Coexpression of CCL21 and Her-2/neu resulted in induction of a TH1-polarized immune response and substantial improvement of the protective effect of the DNA vaccine. Coexpression of tumor antigen pDNA(Her2/neu) with both pDNA(GM-CSF) and pDNA(CCL21) as adjuvants led to further improvement of protection by the vaccine (70% tumor-free mice on day 35 vs 40% with either adjuvant alone vs 5-10% with tumor antigen alone). Our results show that CCL21 is a potent adjuvant for DNA vaccination, particularly in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF). Clinical use of a pDNA(Her2/neu/CCL21/GM-CSF) vaccine might be particularly promising in minimal residual Her2/neu+ breast cancer.

CCL19 (ELC) as an adjuvant for DNA vaccination: induction of a TH1-type T-cell response and enhancement of antitumor immunity

Coexpression of tumor antigens together with immunomodulatory molecules is a strategy in DNA vaccination aiming at an amplification of the antitumor immune response. Epstein-Barr virus-induced-molecule-1-ligand-chemokine (ELC/CCL19) is a CC chemokine that binds to the chemokine receptor CCR7. CCR7 is expressed on mature dendritic cells (DC) and distinct T- and B-cell subpopulations. CCL19 (ELC) is mainly expressed in secondary lymphoid organs and plays a central role in regulating the encounters between DC and T cells. We asked whether CCL19 is able to augment immunogenicity of a DNA vaccine in a C57BL/6 mouse model with syngeneic MCA205 (beta-gal) tumor cells. Mice were vaccinated twice intramuscularly on days 1 and 15 and tumor challenge was performed subcutaneously on day 25. Coadministration of plasmid DNA (pDNA) (beta-gal) plus pDNA (CCL19) was compared with pDNA (beta-gal), pDNA (CCL19), mock vector and phosphate-buffered saline (PBS) alone. Coexpression of CCL19 resulted in enhancement of a Th1-polarized immune response with substantial improvement of the protective effect of the DNA vaccine. Immunohistochemical staining revealed an increased CD8+ T-cell infiltration in the tumor tissue of mice that had been immunized with pDNA (beta-gal) plus pDNA (CCL19). We conclude that CCL19 is an attractive adjuvant for DNA vaccination able to augment antitumor immunity and that this effect is partially caused by enhanced CD8+ T-cell recruitment.

Enhanced tumorigenicity of fibroblasts transformed with human herpesvirus 8 chemokine receptor vGPCR by successive passage in nude and immunocompetent mice

The human herpes virus 8 (HHV-8)-encoded G protein-coupled chemokine receptor (vGPCR) has been implicated in the pathogenesis of Kaposi's sarcoma (KS), particularly because of its high constitutive signaling activity. Here, we used retroviral transduction to generate vGPCR-expressing 3T3 fibroblasts that are tumorigenic in nude mice, but as expected fail to induce tumors in their immunocompetent counterparts. However, tumor fragments obtained from nude mice grow progressively in immunocompetent BALB/c mice. Unexpectedly, vGPCR-expressing cells established from grafted tumor fragments gave rise to tumors in immunocompetent mice. These tumors exhibit a striking histological resemblance to KS including plump spindle cell morphology, a high degree of vascularization and brisk mitotic activity. High expression of vGPCR was confirmed in the cell lines and tumors using a newly developed vGPCR-specific monoclonal antibody. Finally, short interfering RNA directed at vGPCR abrogated or significantly delayed tumorigenesis in mice, demonstrating that the tumor development is specifically driven by vGPCR. This novel model for vGPCR-mediated oncogenesis will contribute to our understanding of the role of vGPCR in the pathogenesis of HHV-8 and may even be important in identifying critical molecular and epigenetic changes during tumor progression in vivo.

Shaping up adaptive immunity: the impact of CCR7 and CXCR5 on lymphocyte trafficking

The effective onset of adaptive immune responses requires that naïve antigen-specific lymphocytes, being inherently rare throughout the body, rapidly encounter foreign antigens. This problem has been elegantly solved in evolution by inventing secondary lymphoid tissues as intersections in the migratory pathway of antigen-presenting dendritic cells and antigen-specific lymphocytes. Chemokines play a central role in guiding cell movements in the course of immune responses and in lymphoid system homeostasis. In particular, the chemokine receptors CCR7 and CXCR5 are key molecules for the entry of lymphocytes and dendritic cells into secondary lymphoid organs and their homing to T-cell and B-cell zones therein. CCR7 and CXCR5 are differentially expressed on the cell surface of lymphocytes and dendritic cells depending of the stage of cellular differentiation and activation, thus allowing these cells to change their homing capacity and prospective traffic routes.

CD4+CD3- cells induce Peyer's patch development: role of alpha4beta1 integrin activation by CXCR5

CD4+CD3- cells are the predominant hematopoietic cells found in mouse fetal intestine. We prove their role as Peyer's patch (PP)-inducing cells by transfer into neonatal PP-deficient mice. To test the requirement of chemokines and adhesion molecules in induction of PP, we studied mice deficient in CXCR5 and/or alpha4beta1 integrin-mediated adhesion. CXCR5-/- mice have CD4+CD3- cells, which are inefficient in inducing PP formation. We show here that CXCR5/CXCL13 signaling activates alpha4beta1 integrin on CD4+CD3- cells. Blocking of beta1 integrin or VCAM-1, the ligand of alpha4beta1 integrin, inhibits PP formation. This study demonstrates the link between chemokine receptors and adhesion molecules that regulates stromal/hematopoietic cell interaction leading to PP formation.

CC chemokine receptor 7-dependent and -independent pathways for lymphocyte homing: modulation by FTY720

Cognate interaction of chemokine receptor CCR7 on lymphocytes with its ligands CCL19 and CCL21 expressed on high endothelial venules (HEVs) is essential for effective migration of T and B cells across HEVs into secondary lymphoid organs. Plt mice, which lack expression of CCL19 and CCL21-ser, both ligands for CCR7 on HEVs, as well as CCR7-deficient mice, have a defective cell migration and reduced homing of lymphocytes. FTY720, a novel immunosuppressant, causes a reduction of lymphocytes in peripheral blood and tissues and their sequestration into lymphoid tissues. In this study we demonstrate that FTY720 rescues the homing defect in both CCR7(-/-) mice and plt mice. After FTY720 treatment, the number of CD4(+) and CD8(+) T cells as well as B cells in peripheral blood is reduced while pertussis toxin-sensitive homing into peripheral lymph nodes, mesenteric lymph node, and Peyer's patches is increased. Immunohistology demonstrates that FTY720 enables these cells to enter lymphoid tissue through HEVs. Thus, our data suggest an alternative G-alpha(i)-dependent, CCR7-CCL19/CCL21-independent mechanism for lymphocyte homing through HEVs which is strongly augmented in the presence of FTY720.

Tumorigenesis induced by the HHV8-encoded chemokine receptor requires ligand modulation of high constitutive activity

ORF74 (or KSHV-vGPCR) is a highly constitutively active G protein-coupled receptor encoded by HHV8 that is regulated both positively and negatively by endogenous chemokines. When expressed in transgenic mice, this chemokine receptor induces an angioproliferative disease closely resembling Kaposi sarcoma (KS). Here we demonstrate that several lines of mice carrying mutated receptors deficient in either constitutive activity or chemokine regulation fail to develop KS-like disease. In addition, animals expressing a receptor that preserves chemokine binding and constitutive activity but that does not respond to agonist stimulation have a much lower incidence of angiogenic lesions and tumors. These results indicate that induction of the KS-like disease in transgenic mice by ORF74 requires not only high constitutive signaling activity but also modulation of this activity by endogenous chemokines.

The T cell chemokine receptor CCR7 is internalized on stimulation with ELC, but not with SLC

ELC and SLC are potent agonists for CCR7, a receptor of up-most importance for the regulation of the homing and traffic of lymphocytes into and within secondary lymphoid tissues. We have studied the effects of both chemokines on receptor re-distribution in T lymphocytes and other CCR7-bearing cells by flow cytometry and by assessing receptor mediated functions. In this paper we show that ELC and SLC differ fundamentally in the ability to induce the internalization of their receptor. ELC induced a rapid time- and concentration-dependent internalization of CCR7 and markedly decreased the ability of CCR7-bearing cells to respond to a second stimulation. No receptor internalization, by contrast, was observed on stimulation with SLC. Receptors that were internalized on stimulation with ELC were re-expressed when the cells were washed. Re-expression of receptors and consequent re-activation of the cells was prevented in the presence of ELC, but was not affected in the presence of SLC. These findings could explain how T lymphocytes that enter lymphoid tissues in response to SLC produced by high-endothelial venules can subsequently migrate in response to SLC and ELC expressed within the T cell areas.

Signal transduction by the chemokine receptor CXCR5: structural requirements for G protein activation analyzed by chimeric CXCR1/CXCR5 molecules

The human chemokine receptors CXCR5 and CXCR1 activate signaling pathways via pertussis toxin-sensitive as well as insensitive G proteins. CXCR5 induces Ca2+ signaling and chemotaxis independently of inhibitory G proteins, whereas the same signaling pathways are entirely dependent on inhibitory G proteins for CXCR1. In contrast, activation of the MAP kinase cascade via ERK1/2 is a pertussis toxin-sensitive signaling event for both receptors. Using chimeric CXCR1/CXCR5 receptors we investigated structural requirements for the activation of signal transduction pathways by CXCR5. Individual or multiple intracellular domains of CXCR1 were exchanged for the corresponding sequences of CXCR5, leading to receptors resembling CXCR5 at the cytoplasmic surface to a varying extent. Replacing the second intracellular domain of CXCR1 had a major influence on signaling mediated by inhibitory G proteins, whereas the exchange of the third or carboxy-terminal intracellular domain had only minor effects on signal transduction. Activation of the MAP kinase cascade via ERK1/2 and chemotaxis are largely reduced in chimeras comprising the second intracellular domain of CXCR5, although coupling to inhibitory G proteins is retained in all chimeric receptors. In summary, these data characterize the contribution of the intracellular domains of CXCR5 to receptor signaling, thereby disclosing unique structural requirements that modulate G protein coupling by the receptor.

The poliovirus receptor CD155 mediates cell-to-matrix contacts by specifically binding to vitronectin

The human receptor for poliovirus (CD155) is an immunoglobulin-like molecule with unknown normal function(s). Here we provide evidence that CD155 binds specifically to vitronectin with a dissociation constant (K(d)) of 72 nM as determined by surface plasmon resonance. Based on sequence homology to the CD155 gene, three poliovirus receptor-related genes (PRR1, PRR2, and PRR3) were cloned recently. PRR proteins were reported by others to mediate homophilic cell adhesion. Neither PRR1 nor PRR2 binds poliovirus and it is assumed that their physiological functions differ from that of CD155. Indeed, mPRR2 was found to bind to vitronectin only weakly, while its self-adhesion activity is characterized by a K(d) of 310 nM. Moreover, there is no evidence for CD155 self-adhesion. Both CD155 and vitronectin colocalize to follicular dendritic cells and B cells inside the germinal centers of secondary lymphoid tissue (tonsils)-an observation suggesting that the CD155/vitronectin interaction is required for the establishment of a proper immune response in this particular context.

Involvement of inhibitory NKRs in the survival of a subset of memory-phenotype CD8+ T cells

Inhibitory natural killer receptors (NKRs) such as killer cell immunoglobulin-like receptors (KIRs) in humans and Ly49 molecules in mice are expressed on NK cells and recognize multiple major histocompatibility (MHC) class I proteins. In humans and mice, a subset of CD8+ T cells also expresses NKRs and harbors a memory phenotype. Using mice that are transgenic for KIR2DL3 and its cognate HLA-Cw3 ligand, we show that engagement of inhibitory NKRs selectively drives the in vivo accumulation of a subset of memory-phenotype CD8+ T cells that express the beta chain of the interleukin 2 receptor. In vitro, recognition of MHC class I molecules by inhibitory NKRs on T cells down-regulated activation-induced cell death. These results unveil an MHC class I-dependent pathway that promotes the survival of a subset of memory-phenotype CD8+ T cells and also reveal an unexpected biological function for inhibitory NKRs on T cells.

Skewed maturation of memory HIV-specific CD8 T lymphocytes

Understanding the lineage differentiation of memory T cells is a central question in immunology. We investigated this issue by analysing the expression of the chemokine receptor CCR7, which defines distinct subsets of naive and memory T lymphocytes with different homing and effector capacities and antiviral immune responses to HIV and cytomegalovirus. Ex vivo analysis of the expression of CD45RA and CCR7 antigens, together with in vitro analysis of the cell-division capacity of different memory CD8+ T-cell populations, identified four subsets of HIV- and CMV-specific CD8+ T lymphocytes, and indicated the following lineage differentiation pattern: CD45RA+ CCR7+ --> CD45RA- CCR7+ --> CD45RA- CCR7- --> CD45RA+ CCR7-. Here we demonstrate through analysis of cell division (predominantly restricted to the CCR7+ CD8+ T-cell subsets) that the differentiation of antigen-specific CD8+ T cells is a two-step process characterized initially by a phase of proliferation largely restricted to the CCR7+ CD8+ cell subsets, followed by a phase of functional maturation encompassing the CCR7- CD8+ cell subsets. The distribution of these populations in HIV- and CMV-specific CD8+ T cells showed that the HIV-specific cell pool was predominantly (70%) composed of pre-terminally differentiated CD45RA- CCR7- cells, whereas the CMV-specific cell pool consisted mainly (50%) of the terminally differentiated CD45RA+ CCR7- cells. These results demonstrate a skewed maturation of HIV-specific memory CD8+ T cells during HIV infection.

Urokinase stimulates human vascular smooth muscle cell migration via a phosphatidylinositol 3-kinase-Tyk2 interaction

Janus kinases Jak1 and Tyk2 play an important role in urokinase-type plasminogen activator (uPA)-dependent signaling. We have recently demonstrated that both kinases are associated with the uPA receptor (uPAR) and mediate uPA-induced activation of signal transducers and activators of transcription (Stat1, Stat2, and Stat4) in human vascular smooth muscle cells (VSMC). Janus kinases are not only required for Stat activation but may also interfere with other intracellular signaling pathways. Here we report that in VSMC, Tyk2 interacts with a downstream signaling cascade involving phosphatidylinositol 3-kinase (PI3-K). We demonstrate that uPA induces PI3-K activation, which is abolished in VSMC expressing the dominant negative form of Tyk2. The regulatory subunit p85 of PI3-K co-immunoprecipitates with Tyk2 but not with Jak1, Jak2, or Jak3, and uPA stimulation increases the PI3-K activity in Tyk2 immunoprecipitates. Tyk2 directly binds to either of the two Src homology 2(SH2)p85 domains in a uPA-dependent fashion. We provide evidence that the Tyk2-mediated PI3-K activation in response to uPA is required for VSMC migration. Thus, two unrelated structurally distinct specific inhibitors of PI3-K, wortmannin and LY294002, prevent VSMC migration induced by uPA. No migratory effect of uPA was observed in VSMC expressing the dominant negative form of Tyk2. Our results underscore the versatile function of Tyk2 in uPA-related intracellular signaling and indicate that PI3-K plays a selective role in the regulation of VSMC migration.

CXC chemokine receptor 5 expression defines follicular homing T cells with B cell helper function

Leukocyte traffic through secondary lymphoid tissues is finely tuned by chemokines. We have studied the functional properties of a human T cell subset marked by the expression of CXC chemokine receptor 5 (CXCR5). Memory but not naive T cells from tonsils are CXCR5(+) and migrate in response to the B cell-attracting chemokine 1 (BCA-1), which is selectively expressed by reticular cells and blood vessels within B cell follicles. Tonsillar CXCR5(+) T cells do not respond to other chemokines present in secondary lymphoid tissues, including secondary lymphoid tissue chemokine (SLC), EBV-induced molecule 1 ligand chemokine (ELC), and stromal cell-derived factor 1 (SDF-1). The involvement of tonsillar CXCR5(+) T cells in humoral immune responses is suggested by their localization in the mantle and light zone germinal centers of B cell follicles and by the concomitant expression of activation and costimulatory markers, including CD69, HLA-DR, and inducible costimulator (ICOS). Peripheral blood CXCR5(+) T cells also belong to the CD4(+) memory T cell subset but, in contrast to tonsillar cells, are in a resting state and migrate weakly to chemokines. CXCR5(+) T cells are very inefficient in the production of cytokines but potently induce antibody production during coculture with B cells. These properties portray CXCR5(+) T cells as a distinct memory T cell subset with B cell helper function, designated here as follicular B helper T cells (T(FH)).

A shift in the phenotype of melan-A-specific CTL identifies melanoma patients with an active tumor-specific immune response

In a significant proportion of melanoma patients, CTL specific for the melan-A(26/7-35) epitope can be detected in peripheral blood using HLA-A2/peptide tetramers. However, the functional capacity of these CTL has been controversial, since although they prove to be effective killers after in vitro expansion, in some patients they have blunted activation responses ex vivo. We used phenotypic markers to characterize melan-A tetramer(+) cells in both normal individuals and melanoma patients, and correlated these markers with ex vivo assays of CTL function. Melanoma patients with detectable melan-A tetramer(+) cells in peripheral blood fell into two groups. Seven of thirteen patients had a CCR7(+) CD45R0(-) CD45RA(+) phenotype, the same as that found in some healthy controls, and this phenotype was associated with a lack of response to melan-A peptide ex vivo. In the remaining six patients, melan-A tetramer(+) cells were shifted toward a CCR7(-) CD45R0(+) CD45RA(-) phenotype, and responses to melan-A peptide could be readily demonstrated ex vivo. When lymph nodes infiltrated by melan-A-expressing melanoma cells were examined, a similar dichotomy emerged. These findings demonstrate that activation of melan-A-specific CTL occurs in only some patients with malignant melanoma, and that only patients with such active immune responses are capable of responding to Ag in ex vivo assays.

Salvage surgery after failure of nonsurgical therapy for carcinoma of the larynx and hypopharynx

BACKGROUND

For larynx preservation, radiotherapy is gaining popularity for primary treatment of laryngeal and hypopharyngeal cancer, reserving surgery for salvage.

OBJECTIVE

To analyze the outcome of salvage surgery after failure of primary radiotherapy.

DESIGN

Nine-year retrospective outcome analysis.

SETTING

University referral center.

PATIENTS

Fifty-four patients with squamous cell carcinoma of the larynx (n = 39) or hypopharynx (n = 15).

RESULTS

For laryngeal cancer, mean interval from radiation to detection of recurrence was 14.5 months (range, 2-66 months). Twenty-three patients (59%) presented with a more advanced tumor stage after radiation than at the initial evaluation. Total laryngectomy was needed in 36 patients (92%). Disease-specific 5-year survival rate was 63%. Survival of patients with small recurrent tumors was statistically significantly better than those with advanced tumors (P =.004). For hypopharyngeal cancer, mean interval from radiation to detection of the recurrence was 10.6 months (range, 3-40 months). Total laryngopharyngectomy was needed in 8 of 9 patients with local recurrrence; neck dissection, in 6 patients with regional recurrence. Disease-specific 5-year survival rate was only 20%. Recurrent tumor and node stages did not influence the outcome. Patients with regional recurrences did no better than those with local ones.

CONCLUSIONS

Salvage surgery in laryngeal cancer achieves good results, especially for small recurrences. Because of tumor progression, larynx preservation is seldom possible at the time of salvage. Salvage surgery in hypopharyngeal cancer shows poor survival regardless of tumor stage and despite radical surgical procedures, and can be recommended only for carefully selected patients. Arch Otolaryngol Head Neck Surg. 2000;126:1473-1477

Sciatic nerve blockade with lipid-protein-sugar particles containing bupivacaine

PURPOSE

To assess the efficacy of lipid-protein-sugar particles (LPSPs) in providing prolonged duration local anesthesia by percutaneous injection.

METHODS

Bupivacaine-containing LPSPs were characterized and optimized in vitro. Male Sprague-Dawley rats were given sciatic nerve blocks with bupivacaine-containing LPSPs. Sensory and motor nerve blockade were measured in the hindpaw, as were contralateral functional deficits (a measure of systemic drug distribution). Poly(lactic-co-glycolic) acid (PLGA) microspheres were used as a reference.

RESULTS

10% (w/w) bupivacaine LPSPs (60% dipalmitoylphosphatidylcholine) were 4.4+/-0.39 microm in diameter, with a tap density of 0.11 +/-0.04 g/ml. These LPSPs and 50% (w/w) PLGA microspheres had comparable durations of sensory blockade (468+/-210 min vs. 706+/-344 min, p = 0.08), although the LPSPs produced a much lesser duration of motor blockade (508+/-258 min vs. 1062+/-456 min, p = 0.005). Systemic toxicity was minimal in both groups.

CONCLUSIONS

LPSPs provide sensory blockade durations comparable to those from PLGA microspheres, with a smaller amount of drug loading. Motor blockade is shorter with LPSPs than with PLGA microspheres. LPSPs appear to be suitable for extended nerve blockade. Given their size and low density, they may be useful for topical anesthesia of the airway.

A chemokine-driven positive feedback loop organizes lymphoid follicles

Lymphoid follicles are B-cell-rich compartments of lymphoid organs that function as sites of B-cell antigen encounter and differentiation. CXC chemokine receptor-5 (CXCR5) is required for B-cell migration to splenic follicles, but the requirements for homing to B-cell areas in lymph nodes remain to be defined. Here we show that lymph nodes contain two types of B-cell-rich compartment: follicles containing follicular dendritic cells, and areas lacking such cells. Using gene-targeted mice, we establish that B-lymphocyte chemoattractant (BLC/BCA1) and its receptor, CXCR5, are needed for B-cell homing to follicles in lymph nodes as well as in spleen. We also find that BLC is required for the development of most lymph nodes and Peyer's patches. In addition to mediating chemoattraction, BLC induces B cells to up-regulate membrane lymphotoxin alpha1beta2, a cytokine that promotes follicular dendritic cell development and BLC expression, establishing a positive feedback loop that is likely to be important in follicle development and homeostasis. In germinal centres the feedback loop is overridden, with B-cell lymphotoxin alpha1beta2 expression being induced by a mechanism independent of BLC.

"Recommendations for uniform reporting of data following major trauma--the Utstein style" (as of July 17, 1999). An International Trauma Anaesthesia and Critical Care Society (ITACCS)

Basic and advanced care of trauma patients has always been an important aspect of prehospital and immediate in-hospital emergency medicine, involving a broad spectrum of disciplines, specialties and skills delivered through Emergency Medical Services Systems which, however, may differ significantly in structure, resources and operation. This complex background has, at least in part, hindered the development of a uniform pattern or set of criteria and definitions. This in turn has hitherto rendered data incompatible, with the consequence that such differing systems or protocols of care cannot be readily evaluated or compared with acceptable validity. Guided by previous consensus processes evolved by the ERC, the AHA and other International Organizations--represented in ILCOR--on 'Uniform reporting of data following out-of-hospital and in-hospital cardiac arrest--the Utstein style' an international working group of ITACCS has drafted a document, 'Recommendations for uniform reporting of data following major trauma--the Utstein style'. The reporting system is based on the following considerations: A structured reporting system based on an "Utstein style template" which would permit the compilation of data and statistics on major trauma care, facilitating and validating independent or comparative audit of performance and quality of care (and enable groups to challenge performance statistics which did not take account of all relevant information). The recommendations and template should encompass both out-of-hospital and in-hospital trauma care. The recommendations and template should further permit intra- and inter-system evaluation to improve the quality of delivered care and identification of the relative benefits of different systems and innovative initiatives. The template should facilitate studies setting out to improve epidemiological understanding of trauma; for example such studies might focus on the factors that determine survival. The document is structured along the lines of the original Utstein Style Guidelines publication on 'prehospital cardiac arrest'. It includes a glossary of terms used in the prehospital and early hospital phase and definitions, time points and intervals. The document uses an almost identical scheme for illustrating the different process time clocks--one for the patient, one for the dispatch centre, one for the ambulance and, finally, one for the hospital. For clarity, data should be reported as core data (i.e. always obtained) and optional data (obtained under specific circumstances). In contrast to the graphic approach used for the Utstein template for pre- or in-hospital cardiac arrest, respectively, the present template introduces, for the time being, at least, a number of terms and definitions and a semantic rather than a graphic report form. The document includes the following sections: The Section Introduction and background The Section on Trauma Data Structure Development: presents a general outline of the development of structured data using object-orientated modelling (which will be discussed in due course) and includes a set of explanatory illustrations. The Section on Terms and Definitions: outlines terms and definitions in trauma care, describing different types of trauma (blunt, penetrating, long bone, major/combined, multiple/polytrauma and predominant trauma). The Section on Factors relating to the circumstances of the injury describes the following items: cause of injury (e.g. type of injury (blunt or penetrating), burns, cold, crush, laceration, amputation, radiation, multiple, etc. Severity of Injury e.g. prehospital basic abbreviated injury score developed by the working group. The score contains anatomical and physiological disability data, with the anatomical scale ranging ordinally from 1. Head to 9. External; the physiological disability scale ranging ordinally from 0--unsurvivable. Mechanism of injury recording for transportation incidents etc. e.g. the type of impact, po

Validation of an immunoassay for detection and quantitation of a genetically modified soybean in food and food fractions using reference materials: interlaboratory study

An immunoassay for detection of a specific genetically modified soybean (Roundup-Ready) was validated on dried soybean powder in an interlaboratory study. Different percentages of genetically modified soybeans in nonmodified soybean matrix were evaluated in a blind study. Thirty-eight laboratories from 13 countries participated. The immunoassay was evaluated for 2 endpoints: (1) To give a semiquantitative result, i.e., determination of a given sample above or below a given threshold, or (2) to compute a quantitative result, i.e., percentage of genetically modified soybeans in the sample. Semiquantitative results showed that a given sample which contained <2% genetically modified soybeans was identified as below 2% with a 99% confidence level. Quantitative use of the assay resulted in a repeatability (r) and reproducibility (R) that were computed to be RSDr = 7% and RSDR = 10%, respectively, for a sample containing 2% genetically modified soybeans. Application of this method depends on availability of appropriate reference materials for a specific food matrix. Only matrix-matched reference materials can be used for analysis of food or food fractions.

NKX2.3 is required for MAdCAM-1 expression and homing of lymphocytes in spleen and mucosa-associated lymphoid tissue

Targeted disruption of the transcription factor NKX2.3 gene in mice results in anatomical defects of intestine and secondary lymphoid organs. Here, we report that spleen and Peyer's patches of NKX2. 3-deficient mice are considerably reduced in size and lack the ordered tissue architecture. T and B cells are misplaced within the spleen and mesenteric lymph nodes and fail to segregate into the appropriate T and B cell areas. Furthermore, splenic marginal zones, characterized by specific B cells and various types of macrophage-derived cells around the marginal sinus, are absent in mutants. Homozygous NKX2.3 mutants lack the mucosal addressin cell adhesion molecule-1 (MAdCAM-1) that is normally expressed in mucosa-associated lymphoid tissue (MALT) and spleen. We provide evidence that NKX2.3 can activate MAdCAM-1 transcription directly, suggesting that MAdCAM-1 is at least partly responsible for the migration and homing defects of lymphocytes and macrophages in mutants. Therefore, expression of MAdCAM-1 seems to be required for building functional structures in spleen and MALT, a prerequisite for unimpaired migration and segregation of B and T cells to and within these organs.

CCR6 mediates dendritic cell localization, lymphocyte homeostasis, and immune responses in mucosal tissue

Chemokine-directed migration of leukocyte subsets may contribute to the qualitative differences between systemic and mucosal immunity. Here, we demonstrate that in mice lacking the chemokine receptor CCR6, dendritic cells expressing CD11c and CD11b are absent from the subepithelial dome of Peyer's patches. These mice also have an impaired humoral immune response to orally administered antigen and to the enteropathic virus rotavirus. In addition, CCR6(-/-) mice have a 2-fold to 15-fold increase in cells of select T lymphocyte populations within the mucosa, including CD4+ and CD8+ alphabeta-TCR T cells. By contrast, systemic immune responses to subcutaneous antigens in CCR6(-/-) mice are normal. These findings demonstrate that CCR6 is a mucosa-specific regulator of humoral immunity and lymphocyte homeostasis in the intestinal mucosa.

Identification of a nuclear respiratory factor-1 binding site within the core promoter of the human polio virus receptor/CD155 gene

In this report we describe a cis-acting element within the core promoter of the CD155 gene specifying the polio virus receptor that is bound by the nuclear respiratory factor-1 (NRF-1) transcription factor. DNase I footprint analysis identified a nuclear protein binding site from -282 to -264 nucleotides upstream of the translation initiation codon of the CD155 gene, which we have called foot print IV (FPIV). Linker scanning mutagenesis revealed that a tandem repeat motif, GCGCAGGCGCAG, located within FPIV was essential for the basal activity of the CD155 core promoter. The results of the electrophoretic mobility shift assay experiments suggested that identical FPIV binding activities were present in a variety of nuclear extracts and that the tandem repeat was essential for binding. A one-hybrid screen was then carried out using FPIV as bait to clone the cDNA of the FPIV binding factor. The sequences of the cDNAs that were cloned from the screen were identical to NRF-1, a result that was confirmed by further electrophoretic mobility shift assay experiments. Overexpression of full-length NRF-1 and a dominant-negative form of NRF-1 modulated reporter gene expression driven by the core promoter. Remarkably, CD155 is the first gene shown to be regulated by NRF-1 that possesses an expression profile during embryogenesis correlating with this factor's proposed role in the development of the vertebrate optic system. We propose that NRF-1, which has been shown by others to be expressed during embryogenesis in animal systems, may be involved in regulating the expression of CD155 at specific stages of central nervous system development.

Sphingosine-1-phosphate is a ligand for the G protein-coupled receptor EDG-6

EDG-6 is a recently cloned member of the endothelial differentiation gene (EDG) G protein-coupled receptor family that is expressed in lymphoid and hematopoietic tissue and in the lung. Homology of EDG-6 to the known sphingosine-1-phosphate (SPP) receptors EDG-1, EDG-3, and EDG-5 and lysophosphatidic acid (LPA) receptors EDG-2 and EDG-4 suggested that its ligand may be a lysophospholipid or lysosphingolipid. We examined the binding of [(32)P]SPP to HEK293 cells, transiently transfected with cDNA encoding EDG-6. Binding of [(32)P]SPP was saturable, demonstrating high affinity (K(D) = 63 nmol/L). Binding was also specific for SPP, as only unlabeled SPP and sphinganine-1-phosphate, which lacks the trans double bond at the 4 position, potently displaced radiolabeled SPP. LPA did not compete for binding of SPP at any concentration tested, whereas sphingosylphosphorylcholine competed for binding to EDG-6, but only at very high concentrations. In addition, SPP activated extracellular signal-regulated kinase (Erk) in EDG-6 transfected cells in a pertussis toxin-sensitive manner. These results indicate that EDG-6 is a high affinity receptor for SPP, which couples to a G(i/o) protein, resulting in the activation of growth-related signaling pathways. (Blood. 2000;95:2624-2629)

Phosphorylation of Oct-2 at sites located in the POU domain induces differential down-regulation of Oct-2 DNA-binding ability

We compared the effects of phosphorylation of Oct-2 protein on its binding to the consensus octamer sequence (ATGCAAAT) and two non-canonical sequences present in human (AAGCAAAT) and murine (AAACAAAT) promoters of the BLR1 (Burkitts' lymphoma receptor 1) gene encoding chemokine receptor CXCR5 (CXC-chemokine receptor 5). The latter cis-acting elements represent low-affinity recognition sequences for the octamer transcription factors. Okadaic acid was found to induce hyperphosphorylation of Oct-2 specifically in cells of lymphoid lineage. Potentially phosphorylated amino acid residues localized to the POU-specific domain of Oct-2. Whereas binding of Oct-2 to the octamer site from the human BLR1 promoter or to the consensus octamer sequence was unaffected by phosphorylation of this factor, a strong reduction of Oct-2 binding to the octamer site from the murine BLR1 promoter was observed. This finding correlates well with the down-regulation of expression of the BLR1 gene in murine splenic cells but not in lymphoid cells of human origin treated with okadaic acid. These data support the hypothesis that phosphorylation of Oct-2 may be a mechanism by which activities of the promoters containing non-canonical octamer sequences are differentially regulated in response to extracellular stimuli.

CXCR5-deficient mice develop functional germinal centers in the splenic T cell zone

The chemokine receptor CXCR5 is thought to be essential for the migration of B cells into the network of follicular dendritic cells in the spleen. However, as shown here, B cells and follicular dendritic cells do co-localize, albeit aberrantly, even in the absence of CXCR5. In mice lacking CXCR5 both cell types are found in a broad ring around the sinuses of the marginal zones. Upon immunization with the T cell-dependent antigen 2-phenyl-oxazolone, ectopic germinal centers develop in the periarteriolar lymphocyte sheath. A network of follicular dendritic cells forms in the vicinity of the central arteriole within which the antigen-activated B cells proliferate. The analysis of the expressed V gene repertoire revealed that during B cell proliferation, hypermutation is activated and V region genes accumulate somatic mutations. The pattern of somatic mutations suggests that affinity selection may occur. This analysis confirms that in CXCR5-deficient mice, the organization of splenic primary follicles is severely impaired. However, within the T cell zone a micro-environment is built up, which provides all requirements needed for the affinity maturation to take place.

The murine chemokine receptor CXCR4 is tightly regulated during T cell development and activation

We have characterized the murine homolog of the HIV-co-receptor CXCR4 during T cell development and activation. Our data demonstrate that this chemokine receptor, although highly conserved between human and mouse, is differently expressed and regulated in both species. Mitogenic activation resulted in an increase of surface CXCR4 on murine T cells within 2 days, whereas the receptor was strongly down-regulated on human T cells during this period. Furthermore, intraperitoneal immunization of mice resulted in a strong increase of splenic and mesenteric cytotoxic T cells co-expressing CXCR4. It is interesting that, on thymocytes, expression of CXCR4 is restricted to CD4+CD8+ cells. Stromal cell-derived factor-1alpha, a natural ligand of CXCR4, induced chemotaxis of thymocytes and was found to counteract dexamethasone-induced apoptosis to a certain extent in these cells. Thus, our data show that expression of CXCR4 is tightly controlled on murine T cells and indicate that this highly conserved chemokine receptor might serve different functions in humans and mice.

Two subsets of memory T lymphocytes with distinct homing potentials and effector functions

Naive T lymphocytes travel to T-cell areas of secondary lymphoid organs in search of antigen presented by dendritic cells. Once activated, they proliferate vigorously, generating effector cells that can migrate to B-cell areas or to inflamed tissues. A fraction of primed T lymphocytes persists as circulating memory cells that can confer protection and give, upon secondary challenge, a qualitatively different and quantitatively enhanced response. The nature of the cells that mediate the different facets of immunological memory remains unresolved. Here we show that expression of CCR7, a chemokine receptor that controls homing to secondary lymphoid organs, divides human memory T cells into two functionally distinct subsets. CCR7- memory cells express receptors for migration to inflamed tissues and display immediate effector function. In contrast, CCR7+ memory cells express lymph-node homing receptors and lack immediate effector function, but efficiently stimulate dendritic cells and differentiate into CCR7- effector cells upon secondary stimulation. The CCR7+ and CCR7- T cells, which we have named central memory (TCM) and effector memory (TEM), differentiate in a step-wise fashion from naive T cells, persist for years after immunization and allow a division of labour in the memory response.

CCR7 coordinates the primary immune response by establishing functional microenvironments in secondary lymphoid organs

The proper function of immune surveillance requires well-coordinated mechanisms in order to guide the patrolling immune cells through peripheral tissues and into secondary lymphoid organs. Analyzing gene-targeted mice, we identified the chemokine receptor CCR7 as an important organizer of the primary immune response. CCR7-deficient mice show severely delayed kinetics regarding the antibody response and lack contact sensitivity and delayed type hypersensitivity reactions. Due to the impaired migration of lymphocytes, these animals reveal profound morphological alterations in all secondary lymphoid organs. Upon activation, mature skin dendritic cells fail to migrate into the draining lymph nodes. Thus, in order to bring together lymphocytes and dendritic cells to form the characteristic microarchitecture of secondary lymphoid organs, CCR7 is required to rapidly initiate an adoptive immune response.