Typical values of z-resolution for different Digital Breast Tomosynthesis systems evaluated in a multicenter study

PURPOSE

The aim of the present study, conducted by a working group of the Italian Association of Medical Physics (AIFM), was to define typical z-resolution values for different digital breast tomosynthesis (DBT) models to be used as a reference for quality control (QC). Currently, there are no typical values published in internationally agreed QC protocols.

METHODS

To characterize the z-resolution of the DBT models, the full width at half maximum (FWHM) of the artifact spread function (ASF), a technical parameter that quantifies the signal intensity of a detail along reconstructed planes, was analyzed. Five different commercial phantoms, CIRS Model 011, CIRS Model 015, Modular DBT phantom, Pixmam 3-D, and Tomophan, were evaluated on reconstructed DBT images and 82 DBT systems (6 vendors, 9 models) in use at 39 centers in Italy were involved.

RESULTS

The ASF was found to be dependent on the detail size, the DBT angular acquisition range, the reconstruction algorithm and applied image processing. In particular, a progressively greater signal spread was observed as the detail size increased and the acquisition angle decreased. However, a clear correlation between signal spread and angular range width was not observed due to the different signal reconstruction and image processing strategies implemented in the algorithms developed by the vendors studied.

CONCLUSIONS

The analysis led to the identification of typical z-resolution values for different DBT model-phantom configurations that could be used as a reference during a QC program.

Ligand-independent oligomerization of TACI is controlled by the transmembrane domain and regulates proliferation of activated B cells

In mature B cells, TACI controls class-switch recombination and differentiation into plasma cells during T cell-independent antibody responses. TACI binds the ligands BAFF and APRIL. Approximately 10% of patients with common variable immunodeficiency (CVID) carry TACI mutations, of which A181E and C172Y are in the transmembrane domain. Residues A181 and C172 are located on distinct sides of the transmembrane helix, which is predicted by molecular modeling to spontaneously assemble into trimers and dimers. In human B cells, these mutations impair ligand-dependent (C172Y) and -independent (A181E) TACI multimerization and signaling, as well as TACI-enhanced proliferation and/or IgA production. Genetic inactivation of TACI in primary human B cells impaired survival of CpG-activated cells in the absence of ligand. These results identify the transmembrane region of TACI as an active interface for TACI multimerization in signal transduction, in particular for ligand-independent signals. These functions are perturbed by CVID-associated mutations.

Surface Ig variable domain glycosylation affects autoantigen binding and acts as threshold for human autoreactive B cell activation

The hallmark autoantibodies in rheumatoid arthritis are characterized by variable domain glycans (VDGs). Their abundant occurrence results from the selective introduction of N-linked glycosylation sites during somatic hypermutation, and their presence is predictive for disease development. However, the functional consequences of VDGs on autoreactive B cells remain elusive. Combining crystallography, glycobiology, and functional B cell assays allowed us to dissect key characteristics of VDGs on human B cell biology. Crystal structures showed that VDGs are positioned in the vicinity of the antigen-binding pocket, and dynamic modeling combined with binding assays elucidated their impact on binding. We found that VDG-expressing B cell receptors stay longer on the B cell surface and that VDGs enhance B cell activation. These results provide a rationale on how the acquisition of VDGs might contribute to the breach of tolerance of autoreactive B cells in a major human autoimmune disease.

Rapid Antigen and Antibody-Like Molecule Discovery by Staphylococcal Surface Display

Ever since the discovery of antibodies, they have been generated by complicated multi-step procedures. Typically, these involve sequencing, cloning, and screening after expression of the antibodies in a suitable organism and format. Here, a staphylococcal nanobody display is described that omits many the abovementioned intermediate steps and allows for simultaneous screening of multiple targets without prior knowledge nor expression of the binders. This paper reports a detailed, general step-by-step protocol to achieve nanobodies of high affinity. Apart from its focus on radioactive and fluorescent targets, it gives options for various other target formats and additional applications for the staphylococcal library; including flow cytometry and immunoprecipitation. This provides a system for antibody engineers that can be easily adopted to their specific needs.

Antibodies and B cells recognising citrullinated proteins display a broad cross-reactivity towards other post-translational modifications

OBJECTIVE

Autoantibodies against antigens carrying distinct post-translational modifications (PTMs), such as citrulline, homocitrulline or acetyllysine, are hallmarks of rheumatoid arthritis (RA). The relation between these anti-modified protein antibody (AMPA)-classes is poorly understood as is the ability of different PTM-antigens to activate B-cell receptors (BCRs) directed against citrullinated proteins (CP). Insights into the nature of PTMs able to activate such B cells are pivotal to understand the 'evolution' of the autoimmune response conceivable underlying the disease. Here, we investigated the cross-reactivity of monoclonal AMPA and the ability of different types of PTM-antigens to activate CP-reactive BCRs.

METHODS

BCR sequences from B cells isolated using citrullinated or acetylated antigens were used to produce monoclonal antibodies (mAb) followed by a detailed analysis of their cross-reactivity towards PTM-antigens. Ramos B-cell transfectants expressing CP-reactive IgG BCRs were generated and their activation on stimulation with PTM-antigens investigated.

RESULTS

Most mAbs were highly cross-reactive towards multiple PTMs, while no reactivity was observed to the unmodified controls. B cells carrying CP-reactive BCRs showed activation on stimulation with various types of PTM-antigens.

CONCLUSIONS

Our study illustrates that AMPA exhibit a high cross-reactivity towards at least two PTMs indicating that their recognition pattern is not confined to one type of modification. Furthermore, our data show that CP-reactive B cells are not only activated by citrullinated, but also by carbamylated and/or acetylated antigens. These data are vital for the understanding of the breach of B-cell tolerance against PTM-antigens and the possible contribution of these antigens to RA-pathogenesis.

A new branched proximity hybridization assay for the quantification of nanoscale protein-protein proximity

Membrane proteins are organized in nanoscale compartments. Their reorganization plays a crucial role in receptor activation and cell signaling. To monitor the organization and reorganization of membrane proteins, we developed a new branched proximity hybridization assay (bPHA) allowing better quantification of the nanoscale protein-protein proximity. In this assay, oligo-coupled binding probes, such as aptamer, nanobody, and antibodies, are used to translate the proximity of target proteins to the proximity of oligos. The closely positioned oligos then serve as a template for a maximum of 400-fold branched DNA (bDNA) signal amplification. The amplified bPHA signal is recorded by flow cytometer, thus enabling proximity studies with high throughput, multiplexing, and single-cell resolution. To demonstrate the potential of the bPHA method, we measured the reorganization of the immunoglobulin M (IgM)- and immunoglobulin D (IgD)-class B cell antigen receptor (BCR) on the plasma membrane and the recruitment of spleen tyrosine kinase (Syk) to the BCR upon B lymphocyte activation.

Continuous signaling of CD79b and CD19 is required for the fitness of Burkitt lymphoma B cells

Expression of the B-cell antigen receptor (BCR) is essential not only for the development but also for the maintenance of mature B cells. Similarly, many B-cell lymphomas, including Burkitt lymphoma (BL), require continuous BCR signaling for their tumor growth. This growth is driven by immunoreceptor tyrosine-based activation motif (ITAM) and PI3 kinase (PI3K) signaling. Here, we employ CRISPR/Cas9 to delete BCR and B-cell co-receptor genes in the human BL cell line Ramos. We find that Ramos B cells require the expression of the BCR signaling component Igβ (CD79b), and the co-receptor CD19, for their fitness and competitive growth in culture. Furthermore, we show that in the absence of any other BCR component, Igβ can be expressed on the B-cell surface, where it is found in close proximity to CD19 and signals in an ITAM-dependent manner. These data suggest that Igβ and CD19 are part of an alternative B-cell signaling module that use continuous ITAM/PI3K signaling to promote the survival of B lymphoma and normal B cells.

Cell Kinetics Analysis in Patients Affected by Squamous Cell Carcinoma of the Head and Neck Treated with Primary Surgery and Adjuvant Radiotherapy

BACKGROUND

The increasing complexity of management strategies for patients with head and neck squamous cell carcinoma (HN-SCC) calls for the investigation of new objective prognostic parameters to subdivide patients according to the tumor's biological aggressiveness.

METHODS

We evaluated in 35 HN-SCC patients the pretreatment cell kinetics parameters and DNA ploidy after in vivo infusion of bromodeoxyuridine and flow cytometric analysis. Patients were treated with radical surgery followed by conventional radiation therapy. Locoregional control data are available for follow-up times above five years.

RESULTS

We found that the likelihood of locoregional control for patients with rapidly proliferating HN-SCC characterized by a short potential doubling time (Tpot <5 days) was significantly smaller than for HN-SCC patients with slow tumor proliferation (Tpot >5 days). Moreover, when patients were stratified according to DNA ploidy and Tpot value, we found that the locoregional failure rate for rapidly proliferating tumors was significantly higher for diploid HN-SCCs than for aneuploid HN-SCCs.

CONCLUSION

The present data suggest that patients with resectable HN-SCC characterized by fast growth might have a worse prognosis after surgery and adjuvant conventional radiotherapy and might benefit from more aggressive radiotherapeutic modalities.

Immediate loading of three (fixed-on-3) vs four (fixed-on-4) implants supporting cross-arch fixed prostheses: 1-year results from a multicentre randomised controlled trial

PURPOSE

To evaluate the outcome of three (fixed-on-3 = Fo3) vs four (fixed-on-4 = Fo4) implants immediately restored with metal-resin screw-retained cross-arch prostheses in fully edentulous jaws.

MATERIALS AND METHODS

Forty-eight edentulous or to be rendered edentulous patients were randomised in six centres (eight patients per centre) to the Fo3 group (24 patients: 12 maxillae and 12 mandibles) and to the Fo4 group (24 patients: 12 maxillae and 12 mandibles) according to a parallel group design. To be immediately loaded, implants had to be inserted with a minimum torque of 40 Ncm. Outcome measures were prosthesis and implant failures, complications and peri-implant marginal bone level changes evaluated up to 1 year post-loading.

RESULTS

One maxillary prosthesis per group was delayed loaded because implants could not be placed with a torque of at least 40 Ncm. Ten patients in the Fo3 group and four in the Fo4 group had implants placed flapless. One year after loading no drop out occurred. One patient of the Fo3 group lost three implants vs three patients of the Fo4 group who lost four implants, the difference being no statistically significant (risk difference = -0.08; 95% CI: -0.27 to 0.10; Fisher's exact test P = 0.609). One mandibular Fo3 and one maxillary Fo4 prosthesis failed. Six Fo3 patients were affected by complications vs three Fo4 patients (risk difference = 0.12; 95% CI: -0.10 to 0.34; Fisher's exact test; P = 0.461). Both groups lost marginal bone in a statistically significant way (0.22 ± 0.20 mm for Fo3 patients and 0.40 ± 0.21 mm for Fo4 patients), with Fo3 group showing less marginal peri-implant bone loss than Fo4 group (estimate of the difference = -0.18 (standard error: 0.06) mm; 95% CI: -0.30 to -0.06; P = 0.005). There were no differences in clinical outcomes between the six operators.

CONCLUSIONS

These preliminary results suggest that immediately loaded cross-arch prostheses of both jaws can be supported by only three dental implants at least up to 1 year post-loading, though longer follow-ups are definitively needed.

Rapid and Direct VHH and Target Identification by Staphylococcal Surface Display Libraries

Unbiased and simultaneous identification of a specific antibody and its target antigen has been difficult without prior knowledge of at least one interaction partner. Immunization with complex mixtures of antigens such as whole organisms and tissue extracts including tumoral ones evokes a highly diverse immune response. During such a response, antibodies are generated against a variety of epitopes in the mixture. Here, we propose a surface display design that is suited to simultaneously identify camelid single domain antibodies and their targets. Immune libraries of single-domain antigen recognition fragments from camelid heavy chain-only antibodies (VHH) were attached to the peptidoglycan of Gram-positive Staphylococcus aureus employing its endogenous housekeeping sortase enzyme. The sortase transpeptidation reaction covalently attached the VHH to the bacterial peptidoglycan. The reversible nature of the reaction allowed the recovery of the VHH from the bacterial surface and the use of the VHH in downstream applications. These staphylococcal surface display libraries were used to rapidly identify VHH as well as their targets by immunoprecipitation (IP). Our novel bacterial surface display platform was stable under harsh screening conditions, allowed fast target identification, and readily permitted the recovery of the displayed VHH for downstream analysis.

The use of 18F-2-fluorodeoxyglucose (FDG) to label antibody fragments for immuno-PET of pancreatic cancer

We generated ¹⁸F-labeled antibody fragments for PET imaging using a sortase-mediated reaction to install a transcyclooctene (TCO)-functionalized short peptide onto proteins of interest, followed by reaction with a tetrazine-labeled-¹⁸F-2-deoxyfluoroglucose (FDG). The method is rapid, robust, and site-specific (radiochemical yields >25%, not decay corrected). The availability of ¹⁸F-2-deoxyfluoroglucose avoids the need for more complicated chemistries used to generate carbon-fluorine bonds. We demonstrate the utility of the method by detecting heterotopic pancreatic tumors in mice by PET, using anti-Class II MHC single domain antibodies. We correlate macroscopic PET images with microscopic two-photon visualization of the tumor. Our approach provides easy access to ¹⁸F-labeled antibodies and their fragments at a level of molecular specificity that complements conventional¹⁸F-FDG imaging.

Butyrophilin 3A1 binds phosphorylated antigens and stimulates human γδ T cells

Human T cells that express a T cell antigen receptor (TCR) containing γ-chain variable region 9 and δ-chain variable region 2 (Vγ9Vδ2) recognize phosphorylated prenyl metabolites as antigens in the presence of antigen-presenting cells but independently of major histocompatibility complex (MHC), the MHC class I-related molecule MR1 and antigen-presenting CD1 molecules. Here we used genetic approaches to identify the molecule that binds and presents phosphorylated antigens. We found that the butyrophilin BTN3A1 bound phosphorylated antigens with low affinity, at a stoichiometry of 1:1, and stimulated mouse T cells with transgenic expression of a human Vγ9Vδ2 TCR. The structures of the BTN3A1 distal domain in complex with host- or microbe-derived phosphorylated antigens had an immunoglobulin-like fold in which the antigens bound in a shallow pocket. Soluble Vγ9Vδ2 TCR interacted specifically with BTN3A1-antigen complexes. Accordingly, BTN3A1 represents an antigen-presenting molecule required for the activation of Vγ9Vδ2 T cells.

Peroxisome-derived lipids are self antigens that stimulate invariant natural killer T cells in the thymus

The development and maturation of semi-invariant natural killer T cells (iNKT cells) rely on the recognition of self antigens presented by CD1d restriction molecules in thymus. The nature of the stimulatory thymic self lipids remains elusive. We isolated lipids from thymocytes and found that ether-bonded mono-alkyl glycerophosphates and the precursors and degradation products of plasmalogens stimulated iNKT cells. Synthetic analogs showed high potency in activating thymic and peripheral iNKT cells. Mice deficient in the peroxisomal enzyme glyceronephosphate O-acyltransferase (GNPAT), essential for the synthesis of ether lipids, had significant alteration of the thymic maturation of iNKT cells and fewer iNKT cells in both thymus and peripheral organs, which confirmed the role of ether-bonded lipids as iNKT cell antigens. Thus, peroxisome-derived lipids are nonredundant self antigens required for the generation of a full iNKT cell repertoire.

IL-8-mediated angiogenic responses of endothelial cells to lipid antigen activation of iNKT cells depend on EGFR transactivation

iNKT cells are a unique T cell subset, which is CD1d-restricted and specific for glycolipid antigens. In advanced atherosclerotic plaques, focal collections of inflammatory cells correlate with areas of intraplaque neovascularization. We reported recently that iNKT cells might facilitate intraplaque neovascularization by enhancing EC migration and sprouting in an IL-8-dependent manner. This study investigated the participating effector mechanisms. In ECs, CM, derived from antigen-stimulated human iNKT cells (CM+), induced up-regulation of IL-8R CXCR2 and the phosphorylation of EGFR and of multiple intracellular signaling effectors, including FAK, Src, Erk, Jnk, p38-MAPK, and STAT1 and -3. We found that a cascade of events, which were IL-8-dependent and involved EGFR activation, was responsible for signaling through FAK and Src kinases and necessary for acquisition of angiogenic morphology, migration in a two-dimensional wound assay, and sprout outgrowth in a three-dimensional model of angiogenesis in vitro. The data support that IL-8-dependent activation of angiogenic behavior in ECs, in response to activated iNKT, involves CXCR2, transactivation of EGFR, and subsequent FAK/Src signaling. We found too that activated iNKT increased VEGFR2 expression in ECs. Functional studies confirmed that EGF is the motogenic-enhancing factor in CM+ and is necessary, together with an exogenous source of VEGF, for iNKT-promoted sprout formation. EGFR inhibition may represent a novel therapeutic modality aimed at plaque stabilization through control of neovascularization within developing atherosclerotic plaques.

Invariant natural killer T cells: linking inflammation and neovascularization in human atherosclerosis

Atherosclerosis, a chronic inflammatory lipid storage disease of large arteries, is complicated by cardiovascular events usually precipitated by plaque rupture or erosion. Inflammation participates in lesion progression and plaque rupture. Identification of leukocyte populations involved in plaque destabilization is important for effective prevention of cardiovascular events. This study investigates CD1d-expressing cells and invariant NKT cells (iNKT) in human arterial tissue, their correlation with disease severity and symptoms, and potential mechanisms for their involvement in plaque formation and/or destabilization. CD1d-expressing cells were present in advanced plaques in patients who suffered from cardiovascular events in the past and were most abundant in plaques with ectopic neovascularization. Confocal microscopy detected iNKT cells in plaques, and plaque-derived iNKT cell lines promptly produced proinflammatory cytokines when stimulated by CD1d-expressing APC-presenting α-galactosylceramide lipid antigen. Furthermore, iNKT cells were diminished in the circulating blood of patients with symptomatic atherosclerosis. Activated iNKT cell-derived culture supernatants showed angiogenic activity in a human microvascular endothelial cell line HMEC-1-spheroid model of in vitro angiogenesis and strongly activated human microvascular endothelial cell line HMEC-1 migration. This functional activity was ascribed to IL-8 released by iNKT cells upon lipid recognition. These findings introduce iNKT cells as novel cellular candidates promoting plaque neovascularization and destabilization in human atherosclerosis.

Early recycling compartment trafficking of CD1a is essential for its intersection and presentation of lipid antigens

A major step in understanding differences in the nature of Ag presentation was the realization that MHC class I samples peptides transported to the endoplasmic reticulum from the cytosol, whereas MHC class II samples peptides from lysosomes. In contrast to MHC class I and II molecules that present protein Ags, CD1 molecules present lipid Ags for recognition by specific T cells. Each of the five members of the CD1 family (CD1a-e) localizes to a distinct subcompartment of endosomes. Accordingly, it has been widely assumed that the distinct trafficking of CD1 isoforms must also have evolved to enable them to sample lipid Ags that traffic via different routes. Among the CD1 isoforms, CD1a is unusual because it does not have a tyrosine-based cytoplasmic sorting motif and uniquely localizes to the early endocytic recycling compartment. This led us to predict that CD1a might have evolved to focus on lipids that localize to early endocytic/recycling compartments. Strikingly, we found that the glycolipid Ag sulfatide also localized almost exclusively to early endocytic and recycling compartments. Consistent with colocalization of CD1a and sulfatide, wild-type CD1a molecules efficiently presented sulfatide to CD1a-restricted, sulfatide-specific T cells. In contrast, CD1a:CD1b tail chimeras, that retain the same Ag-binding capacity as CD1a but traffic based on the cytoplasmic tail of CD1b to lysosomes, failed to present sulfatide efficiently. Thus, the intracellular trafficking route of CD1a is essential for efficient presentation of lipid Ags that traffic through the early endocytic and recycling pathways.

4,5,6-Trisubstituted piperidinones as conformationally restricted ceramide analogues: synthesis and evaluation as inhibitors of sphingosine and ceramide kinases and as NKT cell-stimulatory antigens

The conformationally based piperidinone sphingosine analogues 7, 8, 15, and 16 were synthesized from allylic alcohol 34 via lactams 31 and 32. The L-arabino diol 7 and the L-ribo diol 8 were transformed into the amino alcohols 17-24. The L-gluco ceramide analogues 43, 46a, and 47, and the L-altro ceramide analogues 51a and 52 were synthesized from either 31 or 32. The L-ribo diols 8 and 16, and the amino alcohols 19 and 20 inhibit sphingosine kinase 1 (SPHK1), while the L-arabino analogues 7, 15, 17, and 18 are inactive. The L-arabino and the L-ribo dimethylamines 21-24, the L-gluco ceramide analogues 43, 46a, and 47, and the L-altro ceramide analogues 51a and 52 did not block SPHK1. Neither the L-arabino diol 7 nor the L-ribo diol 8 inhibited SPHK2 or ceramide kinase. The L-arabino diols 7 and 15 stimulate invariant natural killer T (iNKT) cells when presented by living antigen-presenting cells (APC) and also by plate-bound human CD1d, whereas the L-ribo diols 8 and 16, the L-arabino amino alcohols 17-18, and the dimethylamines 21-22 did not activate iNKT cells. The L-gluco ceramide analogues 43, 46a, and 47 had strongly stimulatory effects on iNKT cells when presented by living APC and also by plate-bound human CD1d, whereas the L-altro ceramide analogue 52 activated only weakly. All activatory compounds induced preferentially the release of pro-inflammatory cytokines, indicating the formation of a stable CD1d--lipid--T-cell receptor complex.

Uncoupling between CD1d upregulation induced by retinoic acid and conduritol-B-epoxide and iNKT cell responsiveness

Gaucher disease (GD) is associated with upregulation of CD1d and MHC-class II expression by monocytes. While the physiological impact of CD1d upregulation remains uncertain, it has been proposed that MHC-class II upregulation is associated with inflammation. Hereby, we show that the decrease in MHC-class II expression seen in GD patients under therapy correlates positively with chitotriosidase activity, a marker of inflamed macrophages. We also show that retinoic acid (RA) and the beta-glucocerebrosidase inhibitor conduritol-B-epoxide (CBE) lead to upregulation of CD1d expression by THP-1 cells, which correlated with an increase in mRNA expression. In vitro co-culture experiments showed that RA treated THP-1 cells were more stimulatory for CD4(+) than for CD8(+) T cells, as determined by CFSE loss, in comparison to untreated THP-1 cells. Interestingly, even though addition of exogenous isoglobotrihexosylceramide (iGb3), a physiological CD1d ligand, augmented the percentage of dividing CD4(+) T cells, we could not detect a significant expansion of CD4(+)Valpha24(+) invariant Natural Killer T (iNKT) cells. In contrast, addition of alpha-galactosylceramide (alpha-GC) induced expansion of Valpha24(+) iNKT cells as determined by using alpha-GC-loaded human CD1d dimers. These results strengthen the existence of a cross-talk between monocyte lipid accumulation, inflammation and changes in cell surface CD1d and MHC-class II in monocytes, which may result in inappropriate recognition events by immune cells and perpetuate chronic inflammation.

Synthesis and evaluation of sphingolipid analogues: modification of the hydroxy group at C(1) of 7-oxasphingosine, and of the hydroxy group at C(1) and the amide group of 7-oxaceramides

The analogues 7-9 of 7-oxaceramide and 7-oxasphingosine were synthesized from the known azidosphingosine 21. The 1,4-disubstituted 1,2,3-triazole analogues 10-16 of ceramides were synthesized by the click reaction of the known azide 24. None of the analogues 7-15 was active as inhibitor of SPHK type 1 and of acid sphingomyelinase, whereas 16 is a weak inhibitor of SPHK1. Triazoles 10, 11, and 15 did not inhibit ceramide phosphorylation by CerK, and none of 7, 8, and 10-15 activated invariant natural killer T (iNKT) cell clones when presented by human CD1d-transfected antigen-presenting cells (APC) or by plate-bound human CD1d [55]. Triazoles 14 and 15 prevent binding of alpha-galactosylceramide (alpha-GalCer) to plate-bound human CD1d and subsequent T-cell response to alpha-GalCer. Only 15 reduced activation by alpha-GalCer significantly and independently of the cytokine measured.

CD1a and MHC class I follow a similar endocytic recycling pathway

CD1 proteins are a family of major histocompatibility complex (MHC) class I-like antigen-presenting molecules that present lipids to T cells. The cytoplasmic tails (CTs) of all human CD1 isoforms, with the exception of CD1a, contain tyrosine-based sorting motifs, responsible for the internalization of proteins by the clathrin-mediated pathway. The role of the CD1a CT, which does not possess any sorting motifs, as well as its mode of internalization are not known. We investigated the internalization and recycling pathways followed by CD1a and the role of its CT. We found that CD1a can be internalized by a clathrin- and dynamin-independent pathway and that it follows a Rab22a- and ADP ribosylation factor (ARF)6-dependent recycling pathway, similar to other cargo internalized independent of clathrin. We also found that the CD1a CT is S-acylated. However, this posttranslational modification does not determine the rate of internalization or recycling of the protein or its localization to detergent-resistant membrane microdomains (DRMs) where we found CD1a to be enriched. We also show that plasma membrane DRMs are essential for efficient CD1a-mediated antigen presentation. These findings place CD1a closer to MHC class I in its trafficking and potential antigen-loading compartments among CD1 isoforms. Furthermore, we identify CD1a as a new marker for the clathrin- and dynamin-independent and DRM-dependent pathway of internalization as well as the Rab22a- and ARF6-dependent recycling pathway.

Regulation of CD1a surface expression and antigen presentation by invariant chain and lipid rafts

In immature dendritic cells (DCs), CD1a is almost exclusively expressed at the cell surface and its membrane organization is poorly understood. In this study, we report that MHC class II, invariant chain (Ii), and CD9 molecules are coimmunoprecipitated with CD1a in immature DCs, and that CD1a/Ii colocalization is dependent on lipid raft integrity. In HeLa-CIITA cells CD1a expression leads to increased Ii trafficking to the cell surface, confirming the relevance of this association. Furthermore, silencing of Ii in DCs induces significant CD1a accumulation on the plasma membrane whereas the total CD1a expression remains similar to that of control cells. These data suggest that CD1a recycling is facilitated by the association with the Ii. The CD1a localization in lipid rafts has functional relevance as demonstrated by inhibition of CD1a-restricted presentation following raft disruption. Overall, these findings identify Ii and lipid rafts as key regulators of CD1a organization on the surface of immature DCs and of its immunological function as Ag-presenting molecule.

Synthesis and evaluation of human T cell stimulating activity of an alpha-sulfatide analogue

A concise synthesis of alpha-sulfatide 1, an analogue of natural glycolipid antigens with potential anti-tumor activity, was performed. Two different approaches to the alpha-glycosidic bond were explored, resulting in a high yield and excellent stereoselectivity. Compound 1 combines the structural features of sulfated beta-GalCer (sulfatide) and alpha-GalCer, which activate specific T cells. alpha-Sulfatide 1 was stimulatory for CD1d-restricted semi-invariant Natural Killer T (iNKT) cell clones, although less potent than alpha-GalCer, while it was not recognized by CD1a-restricted sulfatide-specific T cells.

Stereoselective Synthesis and Immunogenic Activity of the C-Analogue of Sulfatide

[Structure: see text] The C-sulfatide 1b was synthesized through a [2,3]-Wittig sigmatropic rearrangement and a Horner-Wadsworth-Emmons olefination as the key steps. The C-analogue 1b is less immunogenic than natural sulfatide 1a, but induces a preferential secretion of the proinflammatory cytokine IFN-gamma.

Impact of chemotherapy dose-density on radiotherapy dose-intensity after breast conserving surgery

PURPOSE

To evaluate if chemotherapy (CT) dose-intensification jeopardizes radiotherapy (RT) dose-intensity (DI).

PATIENTS AND METHODS

From 1992 to 1997, 247 stage I-II breast cancer patients, treated with conserving surgery, were treated at the National Cancer Institute of Genoa in a randomized study comparing the same CEF regimen delivered every two weeks (CEF14) or three weeks (CEF21). RT was applied to the residual breast at a total dose of 50 Gy in five weeks. Allowance was made for treatment at 2.3 Gy per fraction in order to compensate for gaps (hypofractionation). Radiotherapy DI was expressed as the average total dose received each week, i.e., 'weekly dose-rate' (WDR). The effect of various tumour, treatment and patient-related factors on the endpoint (a delivered WDR of RT < 9.5 Gy) was investigated by univariate analysis. Factors found to have P-value < or = 0.20 were entered in multivariate analysis.

RESULTS

All but three patients (244 of 247, 98.8%) received a cumulative total dose of RT within +/- 10% of that planned. Moreover, most of them (197 of 247, 79.8%) received an average WDR of > or = 9.5 Gy/wk. With univariate analysis the probability of WDR < 9.5 Gy/wk significantly correlated with age, menopausal status, concomitant administration of RT and CT, and white blood cell toxicity. Moreover, a positive effect on WDR was found in patients treated at 2.3 Gy per fraction. The type of treatment (CEF14 vs. CEF21) did not affect the probability of WDR < 9.5 Gy/wk. With multivariate analysis, age (< or = 55 vs. > 55 years, RR = 3.99, 95% CI: 1.89-8.42, P = 0.0003), RT fractionation (conventional vs. hypofractionation, RR = 0.32, 95% CI: 0.15-0.68, P = 0.017) and WBC toxicity (none vs. some, RR = 1.54, 95% CI: 1.06-2.22, P = 0.027) were independent predictors of WDR < 9.5 Gy. Regarding the CT-RT overlap, patients receiving more than two cycles of chemotherapy during radiotherapy had an increased risk of RT delay compared to other patients (RR = 3.74, 95% CI: 1.44-9.48, P = 0.0063).

CONCLUSIONS

There is no evidence of a direct effect of CT dose-density on dose-intensity of RT. However, the concomitant use of CT and RT reduces the possibility of giving a full dose-intensity of RT.

Measurement of ultrashort pulse durations by interferometric autocorrelation: influence of various parameters

The interferometric autocorrelation technique for the measurement of ultrashort pulse durations is studied in detail. Effects of group velocity mismatch, group velocity dispersion, fundamental depletion, and pulse shape are carefully examined. A simple semianalytical calculation is developed that takes group velocity mismatch into account that can be used to predict the validity of this technique with real experimental parameters. A more complete calculation is also presented to analyze the effects of fundamental depletion or phase mismatch. Finally, the influence of the pulse shape is considered and a simple experimental procedure is proposed to determine whether a pulse is transform limited.

Concomitant administration of two standard regimens of chemotherapy and radiotherapy in advanced squamous carcinoma of the head and neck: a feasibility study

BACKGROUND

In advanced squamous cell carcinoma of the head and neck, the superiority of a chemo-radiotherapy combination over radiotherapy alone has been strongly suggested. However, the best modality to combine the two treatments has still to be determinated. A pilot study was designed, testing a combination of two standard chemo- and radiotherapy regimens concomitantly administered.

MATERIALS AND METHODS

26 patients, with unresectable squamous cell carcinoma of the head and neck, were treated with three cycles of chemotherapy (cisplatin 20 mg/m2/day and fluorouracil 200 mg/m2/day as an intravenous bolus, for 5 consecutive days, every 21) simultaneously delivered with radiation (66-70 Gy/33-35 fractions/7 weeks). In order to reduce the mucoseal toxicity. observed in the first 15 patients, 1 week of pause was inserted after the third week of treatment in the subsequent 11 patients.

RESULTS

Grade III-IV mucositis was detected in 40% of patients treated without pause after the third week of treatment and in 9% of those treated with. Complete responses were obtained in 13/26 patients (50%) and partial responses in 8/26 (31%). 1 stable disease, 3 early deaths (1 because of toxicity) and 1 lost before being evaluated were considered as treatment failures (19%).

CONCLUSIONS

This concomitant chemo-radiotherapy approach showed a good antitumour activity but mucoseal toxicity is too high if no pause is planned during the treatment.

Sub-20-fs tunable pulses in the visible from an 82-MHz optical parametric oscillator

We have produced pulses tunable in the 590-666-nm range, with durations down to 13 fs, using an 82-MHz Ti:sapphire second-harmonic-pumped, high-bandwidth, beta-barium borate optical parametric oscillator in a fused-silica prism group-delay-dispersion-compensated, six-mirror folded ring cavity.

[Sulodexide in the prevention of post-mastectomy lymphedema]

Post-mastectomy lymphedema of the upper limb, that can be noticed by 10 to 20 percent of patients with breast cancer, is usually related to some risk factors: use of radiotherapy on the axilla, obesity, venous outflow obstruction, delayed wound healing or infection. The most important contributing factor to postsurgical edema is the development of lymphangitis in the upper limb. Although literature contains numerous accounts on the use of pharmacological agents for the treatment of postmastectomy lymphedema, the results are not satisfactory in term of clinical response and side effects. In the present study we investigate tolerability and feasibility of the use of suledexide in patients, submitted to mastectomy for breast cancer, with an initial lymphedema of the limb omolateral to surgery or other risk factors for the development of a clinical remarkable lymphedema. Our results show that sulodexide is a very satisfactory therapy in term of lack of side effects and good compliance.

Intensified chemotherapy with granulocyte-monocyte colony stimulating factor protection in advanced, relapsed squamous cell carcinoma of the head and neck. A phase I study

BACKGROUND

The administration of granulocyte-monocyte colony stimulating factor (GM-CSF) should allow an increase in the doses of chemotherapy for patients with advanced cancers of the head and neck.

PATIENTS AND METHODS

Eleven patients with histologically proven relapsed squamous cell carcinoma of the head and neck entered this Phase I study based on the combination of cisplatin (20 mg/m2/day for 5 days), escalating doses of 5-fluorouracil, both given by intravenous injection from day 1 to 5, and GM-CSF, 5 micrograms/kg from day 8 to day 19.

RESULTS

The maximum tolerated 5-fluorouracil dosage was 300 mg/m2 i.v. bolus for 5 consecutive days q. 3 weeks. Thrombocytopenia was the limiting factor to further increase of 5-fluorouracil dosage. Moderate to severe stomatitis were quite rare despite the increased dose of the antimetabolite. GM-CSF was well tolerated: no significant local or systemic side effects attributable to this drug were recorded.

CONCLUSIONS

Adding GM-CSF to the combination of cisplatin and 5-fluorouracil allowed to increase 5-fluorouracil dose up to 50% over the conventional dosage. Further increase of the dose was precluded by the development of severe thrombocytopenia.

Chemotherapy in head and neck cancer

Chemotherapy has been used for many years as a palliative approach to advanced squamous cell carcinoma of the head and neck. Regimens employed have slowly evolved during this time, and the combination of cisplatin and 5-fluorouracil is still standard chemotherapy for such a tumour. However, clinical approaches to advanced squamous cell carcinoma of the head and neck are changing dramatically as physicians become increasingly familiar with multidisciplinary treatments. Integrating chemotherapy and radiotherapy, neo-adjuvant or adjuvant treatments and organ preservation are stimulating fields of investigation involving chemotherapy which definitely warrant further investigation.

Concomitant alpha-interferon and chemotherapy in advanced squamous cell carcinoma of the head and neck

The combination of chemotherapy and interferons has been tested in several human tumors but, until now, no clinical data have been reported in head and neck cancer. At the Istituto Nazionale per la Ricerca sul Cancro of Genoa, 14 patients with previously treated SCC-HN underwent the following regimen: cisplatin, 20 mg/m2/day, 5-fluorouracil, 200 mg/m2/day i.v. bolus and recombinant interferon-alpha-2b (r-IFN-alpha-2b) (Intron-A, Shering-Plough), 3 MIU/day i.m., for 5 consecutive days. Recombinant IFN-alpha-2b was also administered, at the same dosage, 3 times per week during the 2 weeks interval among cycles. Grade III-IV hematological toxicity was recorded in 43% of patients. Increasing fatigue, anorexia, and flu-like symptoms were experienced by most patients. For these reasons 9 of 14 patients needed a chemotherapy delay and a r-IFN-alpha-2b discontinuation. Therefore, due to the heavy toxicity observed, accural was terminated early. The overall response rate was 54% (31% CR, 23% PR). Among the 5 patients who never delayed chemotherapy and discontinued r-IFN-alpha-2b, all but one responded. In conclusion, a synergistic activity between chemotherapy and r-IFN-alpha-2b in head and neck cancer cannot be excluded, but, in our opinion, further investigations should consider less aggressive regimens and/or more selected patients.

Oral lesions in children born to HIV-1 positive women

A cohort of 69 children born to HIV-1 positive women was studied to evaluate types, prevalences and relationships to clinical stages of HIV-1-related oral lesions. In addition, relationships among C. albicans biotypes, clinical features of oral candidiasis and HIV-1 disease were investigated. C. albicans biotypes did not correlate with clinical features of oral lesions, disease stages and CD4+ lymphocyte count. Of 8 patients with recurrent oral candidiasis, 4 changed clinical features and 5 changed biotype. Our study pointed out the high frequency (28.9%) of oral lesions, especially caused by fungi and the importance of the examination of the oral cavity in children born to HIV-1 positive women.

Treatment of advanced squamous-cell carcinoma of the head and neck with alternating chemotherapy and radiotherapy

BACKGROUND

For patients with advanced, unresectable squamous-cell carcinoma of the head and neck, radiotherapy is the standard treatment but has poor results. We therefore designed a randomized trial to determine whether alternating chemotherapy with radiotherapy would improve the survival of such patients.

METHODS

Patients in the trial had biopsy-confirmed unresectable, previously untreated Stage III or IV, squamous-cell carcinoma of the oral cavity, pharynx, or larynx. They were randomly assigned to chemotherapy consisting of four cycles of intravenous cisplatin (20 mg per square meter of body-surface area per day for five consecutive days) and fluorouracil (200 mg per square meter per day for five consecutive days) alternating with radiotherapy in three two-week courses (20 Gy per course; 2 Gy per day, five days per week), or to radiotherapy alone (up to 70 Gy; 2 Gy per day, five days per week).

RESULTS

The 80 patients given chemotherapy alternating with radiotherapy and the 77 given radiotherapy alone were comparable in terms of age, sex, performance status, disease stage, and site of the primary tumor. Complete responses were obtained in 42 percent of the patients in the combined-therapy group and 22 percent of those in the radiotherapy group (P = 0.037). The median survival was 16.5 months in the combined-therapy group and 11.7 months in the radiotherapy group (P less than 0.05); the 3-year survival was 41 percent and 23 percent, respectively. Severe mucositis occurred in 19 percent of the patients in the combined-therapy group and 18 percent of those in the radiotherapy group.

CONCLUSIONS

In patients with advanced unresectable squamous-cell carcinoma of the head and neck, chemotherapy alternating with radiotherapy increases the median survival and doubles the probability of survival for three years as compared with radiotherapy alone. However, since local disease cannot be controlled in over half the patients who receive the combined treatment and since almost two thirds die within three years, further improvements in management are necessary.

Combined chemotherapy and radiation therapy in advanced inoperable squamous cell carcinoma of the head and neck. The final report of a randomized trial

Between 1983 and 1986, the National Institute for Cancer Research in Genoa and affiliated institutions conducted a randomized study to compare two different ways of combining chemotherapy (CT) and radiation therapy (RT). One hundred sixteen patients were randomized to receive neoadjuvant CT followed by definitive RT (treatment arm A) or alternating CT and RT. In treatment arm A, RT consisted of 70 Gy to the involved areas and 50 Gy to the uninvolved neck at 2 Gy/fraction, five fractions per week. In treatment arm B, RT consisted of 60 Gy to involved areas and 50 Gy to the uninvolved neck in three courses of 20 Gy each, 2 Gy/fraction, ten fractions/2 weeks alternated with four courses of CT. CT consisted of vinblastine 6 mg/m2 intravenously followed 6 hours later by bleomycin 30 IU intramuscularly, day 1; methotrexate 200 mg intravenously, day 2; leucovorin rescue, day 3. CT was repeated every 2 weeks up to four courses. The same CT was used in both treatment arms of the study. Fifty-five patients were entered in treatment arm A and 61 in treatment arm B. Complete responses were 7/48 and 19/57 in treatment arms A and B, respectively (P less than 0.03). Four-year progression-free survival was 4% in treatment arm A and 12% in treatment arm B (P less than 0.02), and four-year survival was 10% in A and 22% in B (P less than 0.02). Mucosal tolerance was significantly worse in treatment arm B (P less than 0.00004). The subgroup analysis shows the major improvement of alternating CT and RT in patients with the worst prognostic characteristics.

[Lymphoma of the Waldeyer's ring: experience at the National Institute for Cancer Research of Genoa]

Malignant lymphomas account for 3% of all malignant disease in the head and neck area. Twenty-five to fifty percent of all lymphomas arising in this region develop in extra-nodal structures, mostly in the Waldeyer ring. Lymphomas of the Waldeyer ring are comparable to any other lymphomas and prognosis is strictly related to stage and histology. The present paper reports 51 patients with malignant lymphomas arising in the head and neck (25 patients with Waldeyer ring involvement) recorded at the National Institute for Cancer Research, Genoa, Italy, from 1985 to the present. The characteristics of patients with Waldeyer ring involvement are comparable to those reported in the literature. Differences can be found in the median age (older in the present series) and in the incidence of Hodgkin's disease (8%). Patients were treated according to stage: stage I and II received radiation therapy and, in a few selected patients, this was combined with chemotherapy; stage III-IV received chemotherapy followed, in a few selected patients, by radiation therapy. In the present series, survival was related to the involvement of the Waldeyer ring: analysis has shown that survival is better in those patients with only nodal involvement. Nevertheless, these patients usually have a more advanced stage (p = less than 0.03). This finding is quite surprising since all the known prognostic factors are better in the Waldeyer group.