Carbon dots, a powerful non-toxic support for bioimaging by fluorescence nanoscopy and eradication of bacteria by photothermia.

Carbon Dots (CDs) are innovative materials which have potential applications in many fields, including nanomedicine, energy and catalysis. Here CDs were produced by the alkali-assisted ultrasonic route and characterized by several techniques to determine their composition and properties. Fluorescence nanoscopy using single-molecule localization microscopy shows that they have very good photophysical properties and a remarkable blinking behaviour at 405 nm. Moreover, these CDs are a safe material, non-toxic towards different cell lines (cancer and non-cancer cells) even at very high concentration, reflecting an excellent biocompatibility. Photothermia, i.e. their heating capacity under laser irradiation, was evaluated at two wavelengths and at several power densities. The resulting temperature increment was high (5 < ΔT < 45 °C) and appropriate for biomedical applications. Bioimaging and photothermia were then performed on E. coli, a Gram(-) bacterium, incubated with CDs. Remarkably, by photothermia at 680 nm (0.3, 1 and 1.9 W cm-2) or 808 nm (1.9 W cm-2), CDs are able to eradicate bacteria in their exponential and stationary phases. Images obtained by 3D super-resolution microscopy clearly show the different CD distributions in surviving bacteria after mild photothermal treatment. These results confirm that CDs are multifunctional materials with a wide range of biomedical applications.

Expanding conceptualizations of harm reduction: results from a qualitative community-based participatory research study with people who inject drugs.

BACKGROUND: The perspectives of people who use drugs are critical in understanding why people choose to reduce harm in relation to drug use, what practices are considered or preferred in conceptualizations of harm reduction, and which environmental factors interfere with or support the use of harm reduction strategies. This study explores how people who inject drugs (PWID) think about harm reduction and considers the critical imperative of equity in health and social services delivery for this community. METHODS: This community-based participatory research study was conducted in a Canadian urban centre. Using a peer-based recruitment and interviewing strategy, semi-structured qualitative interviews were conducted by and with PWID. The Vidaview Life Story Board, an innovative tool where interviewers and participant co-construct a visual "life-scape" using a board, markers, and customized picture magnets, was used to facilitate the interviews. The topics explored included injection drug use and harm reduction histories, facilitators and barriers to using harm reduction strategies, and suggestions for improving services and supports. RESULTS: Twenty-three interviews with PWID (14 men and 9 women) were analysed, with a median age of 50. Results highlighted an expanded conceptualization of harm reduction from the perspectives of PWID, including motivations for adopting harm reduction strategies and a description of harm reduction practices that went beyond conventional health-focused concerns. The most common personal practices that PWID used included working toward moderation, employing various cognitive strategies, and engaging in community activities. The importance of social or peer support and improving self-efficacy was also evident. Further, there was a call for less rigid eligibility criteria and procedures in health and social services, and the need to more adequately address the stigmatization of drug users. CONCLUSIONS: These findings demonstrated that PWID incorporate many personal harm reduction practices in their daily lives to improve their well-being, and these practices highlight the importance of agency, self-care, and community building. Health and social services are needed to better support these practices because the many socio-structural barriers this community faces often interfere with harm reduction efforts. Finally, "one size does not fit all" when it comes to harm reduction, and more personalized or de-medicalized conceptualizations are recommended.

Molecular cytogenetic characterization of a 4p15.1-pter duplication and a 4q35.1-qter deletion in a recombinant of chromosome 4 pericentric inversion.

To date, 10 cases of recombinant of chromosome 4 pericentric inversion involving sub-bands p14p15 and q35 have been described. We report on the first case analyzed using array-CGH in a female infant presenting psychomotor and growth retardation, facial anomalies, axial hypotonia, short neck, wide spaced nipples and cardiac defects. Conventional karyotype associated to FISH revealed a recombinant chromosome 4 with partial 4p duplication and 4q deletion derived from a paternal pericentric inversion. Array-CGH allowed us to precise rec4 breakpoints: the proposita carried a small 4.82-4.97 Mb 4q35.1 terminal deletion and a large 35.3-36.7 Mb 4p15.1 terminal duplication. Duplications of the distal 2/3 of short arm of chromosome 4 give rise to recognizable craniofacial features but no specific visceral malformation. A contrario small terminal 4q deletions are associated with cardiac defects. This case and review of literature suggest that two genes ArgBP2 and PDLIM3, located at 4q35.1 and both involved in cardiac and muscle development, could be responsible for cardiac defects observed in terminal 4q35.1 deletions.

Pure and complete trisomy 18p due to a supernumerary marker chromosome associated with moderate mental retardation.

Trisomy for the short arm of chromosome 18 or trisomy 18p, is rarely described. We report on a 13-year-old boy with minor facial anomalies, mental retardation, bilateral cryptorchidism associated with a de novo supernumerary marker chromosome (SMC). Using fluorescence in situ hybridization and comparative genomic hybridization analyses, this SMC corresponded to the p arm of chromosome 18 associated with a centromere of either chromosome 13 or 21 and nucleolus organizing regions (NORs). We report here the first case of a pure and complete trisomy 18p due to a SMC. This report and review of literature confirm that the main phenotypic anomaly associated with trisomy 18p is moderate mental retardation.

Comparison of four serum-free, cytokine-free media for analysis of endogenous erythroid colony growth in polycythemia vera and essential thrombocythemia.

INTRODUCTION: The assay of endogenous erythroid colony formation (EEC), a characteristic of polycythemia vera and essential thrombocythemia, is not standardized. In this multicentric study, we tested four semisolid, serum-free, cytokine-free media based on either methylcellulose (M1, M2) or collagen (C1, C2) commercialized for the EEC assay. MATERIALS AND METHODS: Bone marrow mononuclear cells (BMMC) from 73 individuals (62 patients with either polycythemia vera (26), essential thrombocythemia (19), secondary polyglobuly (17) or chronic myeloid leukemia (2) and 11 healthy donors) were grown in parallel in the four media without, or with 0.01 U/ml erythropoietin (EPo). RESULTS: In all four media EEC formation was specific, as it was not observed in cultures of patients with secondary polyglobuly or chronic myeloid leukemia, nor of healthy donors. Analysis of fresh or MGG-stained collagen gel cultures allowed detection of EEC formation significantly more frequently than methylcellulose-based media; addition of 0.01 U/ml of EPo had little or no effect on EEC formation. Collagen-based medium C1 gave better results than the other media tested: the 'C1' EEC assay was positive for 68.2% of polycythemia vera cultures with significantly higher median EEC numbers (6.5/10(5) BMMC for patients with one major criteria of polycythemia vera and 19 and 21/10(5) BMMC for patients with two or three major criteria, respectively). Medium C1 was also better for essential thrombocythemia cultures with 47.4% of positive results but with a low median EEC number (6.7/10(5) BMMC). When associated with the ELISA dosage of serum EPo, the 'C1' EEC assay allowed confirmation or elimination of the diagnosis of polycythemia vera for 91% (20/22) of polyglobulic patients. CONCLUSION: We propose that serum-free collagen-based culture systems be considered to standardize the EEC assay, now part of the new criteria of polycythemia vera.

Use of pathology-specific peripheral blood CD34 thresholds to predict leukapheresis CD34 content with optimal accuracy: a bicentric analysis of 299 leukaphereses.

CD34+ cell counts in peripheral blood (PB) and corresponding numbers of CD34+ cells and colony-forming units-granulocyte/macrophage (CFU-GM) in 299 leukapheresis products of 209 patients undergoing PB progenitor cell (PBPC) mobilization for autologous transplantation in two different centers were analyzed and compared according to diagnosis: non-Hodgkin lymphoma (NHL, 94 leukaphereses), multiple myeloma (MM, 75), Hodgkin's disease (HD, 37), solid tumors (35), and chronic myeloid leukemia (CML, 32). Without separating disease entities, correlations between PB CD34+ cell counts and leukapheresis content of CD34+ cells (r>0.83, P<0.01) and CFU-GM (r>0.81, P<0.01) were excellent. In both centers, a PB CD34 threshold ensuring a leukapheresis yield > 10(6) CD34/kg was determined. This threshold was higher in center 1 than in center 2, and its predictive accuracy (91.4%, i.e., prediction correct 91.4% of the time) was significantly lower than in center 2 (98.4%, P=0.02). When data were analyzed by pathology, PB CD34+ cell counts and leukapheresis content of CD34+ cells and CFU-GM remained well correlated, and in both centers PB CD34 thresholds predictive of a yield > 10(6) CD34/kg per leukapheresis could be determined for each pathology. For most patients, pathology-specific PB CD34 thresholds could be obtained directly from the equation of the PB CD34/leukapheresis CD34 correlation curve; they varied depending on both pathology and center (range: 7-20 x 10(6) CD34/l). Pathology-specific thresholds predicted a leukapheresis yield > or = 10(6) CD34/kg accurately 100% of the time for MM patients in center 2 and HD and solid tumor patients of both centers, resulting in overall rates of accurate prediction of sufficient graft CD34 content of 96.6% in center 1 and 98.9% in center 2.

CD130 rather than CD126 expression is associated with disease activity in multiple myeloma.

We analysed the expression of both components of IL-6R, CD126 the ligand binding protein and CD130 the signal transducing protein, on plasma cells from MGUS and multiple myeloma (MM) cases using flow cytometry. CD126 was detectable in 50% of either MGUS or MM patients without any change of expression during disease progression. In contrast, CD130 expression was up-regulated during tumoural expansion (43% of MM patients at diagnosis versus 88% at relapse). Finally, combining CD126 and CD130 expression we found a significant increase of the percentage of CD126+ CD130+ patients at relapse, underlying the crucial role of IL-6 response in the late stage of MM.

Reactive plasmacytoses are expansions of plasmablasts retaining the capacity to differentiate into plasma cells.

Circulating plasma cells in 10 cases of reactive plasmacytosis had a shared phenotype with early plasma cell (CD19(+) CD38(+) CD138(+) CD40(+) CD45(+) CD11a+ CD49e- CD56(-)). In most cases, a minor subpopulation of CD28(+) plasma cells was also detected. Reactive plasma cells were highly proliferative, suggesting the presence of circulating progenitors (plasmablasts). After CD138(+) plasma cell removal, highly proliferative CD138(-) plasmablasts differentiated into CD138(+) plasma cells within a few days. This differentiation, which was associated with increased CD38 and decreased HLA-DR expression, was further confirmed by a large increase in intracellular Ig content (associated with Ig secretion) and was concomitant with extensive secretion of interleukin-6 (IL-6). The addition of neutralizing anti-IL-6 and anti-CD126 (IL-6 receptor) monoclonal antibodies totally prevented Ig secretion and cell differentiation by inducing apoptosis of plasmablasts, which indicates that IL-6 is an essential survival factor for plasmablasts. This report provides the first characterization of normal plasmablasts and shows that their phenotype is not exactly that of multiple myeloma cells.

Interleukin-8: an autocrine/paracrine growth factor for human hematopoietic progenitors acting in synergy with colony stimulating factor-1 to promote monocyte-macrophage growth and differentiation.

We previously reported that alteration of the function of heterotrimeric Gi2 proteins altered proliferation of murine macrophages in response to colony stimulating factor-1 (CSF-1). Here we show that a Gi2 agonist, C-X-C chemokine interleukin-8 (IL-8), regulates monocyte-macrophage growth and differentiation. In the absence of serum, IL-8 (10 ng/mL) synergized with CSF-1 to stimulate murine monocyte-macrophage proliferation, enhanced proliferation of purified human CD34+ cells and increased the number and size of CSF-1-induced monocyte-macrophage colonies formed by purified CD34+ cells in semisolid medium. Next, as both CD34+ cells and monocyte-macrophages can produce IL-8, we used an anti-human IL-8 antibody to block an eventual activation of IL-8 receptors by autocrine IL-8. Preincubation with anti-human IL-8 antibody (20-40 microg/mL) inhibited the proliferation as well as the monocyte-macrophage colony clonogenicity of purified human CD34+ cells. Hence, in addition to being a powerful neutrophil chemoattractant, IL-8 also acts as an autocrine/paracrine growth factor for human hematopoietic progenitors, promoting the growth and differentiation of cells of monocytic lineage.

Endogenous erythroid and megakaryocytic colony formation in serum-free, cytokine-free collagen gels.

We studied the suitability of collagen-based semisolid medium for assay of endogenous erythroid colony formation performed in myeloproliferative disorders. Bone marrow (BM) mononuclear cells (MNC) from 103 patients suspected of having polycythemia vera (PV, 76 patients) or essential thrombocythemia (ET, 27 patients) were grown in collagen-based, serum-free, cytokine-free semisolid medium. Colony analysis at day 8 or 10 showed that this collagen assay is specific, as endogenous growth of erythroid colonies was never observed in cultures of 16 healthy donors and 6 chronic myelogenous leukemia (CML) patients. Endogenous erythroid colony formation was observed in 53.3% of patients suspected of PV, with only 15.4% of positive cultures for patients with 1 minor PV criterion and 72% (p = 0.009) of positive cultures for patients with > or =2 minor or 1 major PV criterion. Similarly, endogenous growth of erythroid colonies was found in 44.4% of patients suspected of ET, with 31.6% of positive cultures for patients with 1 ET criterion versus 75% for patients with > or =2 ET criteria. In addition, we found that in collagen gels, tests of erythropoietin (EPO) hypersensitivity in the presence of 0.01 or 0.05 U/ml of EPO and tests of endogenous colony-forming units-megakaryocyte (CFU-MK) formation cannot be used to detect PV or ET, as these tests were positive for, respectively, 21.4% and 50% of healthy donors and 83% and 50% of CML patients. A retrospective analysis suggests that collagen assays are more sensitive than methylcellulose assays to assess endogenous growth of erythroid colonies. In summary, serum-free collagen-based colony assays are simple and reliable assays of endogenous growth of erythroid colonies in myeloproliferative diseases. They also appear to be more sensitive than methylcellulose-based assays.

The absence of CD56 (NCAM) on malignant plasma cells is a hallmark of plasma cell leukemia and of a special subset of multiple myeloma.

In this study, we show that malignant plasma cells from patients with either primary (n=12) or secondary (n=15) plasma cell leukemia (PCL) do not express CD56 at all, neither in the bone marrow nor the peripheral blood in 81% of cases. On the other hand, multiple myeloma (MM) at diagnosis overexpress it in 63 of 94 (67%) cases (P=0.0001). In three secondary PCL evaluated serially, CD56 was also lacking at diagnosis showing that CD56 is not downregulated at the end stage of the disease but rather not upregulated in this subset of patients. This last concept is strengthened by the observation that 29% of MM patients lacking CD56 or weakly expressing it at diagnosis present a detectable leukemic phase vs 11% only in CD561 MM (P=0.06). Forty percent of all the CD56(-/weak) malignant plasma cell disorders present or develop a leukemic phase vs only 15% of CD56+ cases (P < 0.008). CD56(-/weak) MM subset is also associated with a significantly less aggressive osteolytic potential (P=0.012). We conclude that the lack or weak expression of CD56 is a characteristic feature of PCL but also delineates a special subset of MM at diagnosis mainly characterized by a lower osteolytic potential and a trend for malignant plasma cells to circulate in the peripheral blood more overtly.

CD28, a marker associated with tumoral expansion in multiple myeloma.

CD28 expression was thoroughly investigated on plasma cells of monoclonal gammopathy of undetermined significance, multiple myeloma (MM), and human myeloma cell lines. CD28+ plasma cells were detected in 19% of 31 monoclonal gammopathy of undetermined significance, 41% of 116 MM, and 100% of 13 human myeloma cell lines. CD28+ myeloma cells were detected in 21 of 79 (26%) MM cases at diagnosis, 13 of 22 (59%) at medullary relapse (P < 0.009), and 14 of 15 (93%) at extramedullary relapse (P = 0.05), including 10 of 10 (100%) secondary plasma cell leukemias (P = 0.05). Serial studies in individual patients confirmed the emergence of CD28+ myeloma cells with tumoral expansion and treatment failure. This was significantly correlated with the expression of CD28 ligand, i.e., CD86 (but not CD80), and with an increase in the proliferative activity (labeling index) of myeloma cells in bone marrow. Whereas the expression of CD56 defines a particular subset of myeloma patients, CD28 is the only antigen for which expression correlates with tumor progression. Our data show that an aggressive compartment of CD28+ and CD86+ myeloma cells emerges during the course of MM in vivo, indicating that CD28 could be aberrantly expressed on highly malignant (possibly mutated) myeloma cells. Conversely, a subset of proliferative plasmablasts coexpressing CD28 and CD86 could be the normal counterpart of the clonogenic myeloma stem cell because a subset of CD28+ plasma cells was observed in 6 of 6 cases of reactive plasmocytosis.

Analysis of platelet recovery after autologous transplantation with G-CSF mobilized CD34+ cells purified from leukapheresis products.

We studied platelet recovery in relation to graft content in CFUs and CD34+ cells in 31 patients with multiple myeloma (21) or non-Hodgkin lymphoma (10) receiving marrow-ablative therapy followed by autologous transplantation with G-CSF mobilized CD34+ cells purified from leukapheresis products. Twelve patients had prolonged post-transplantation thrombopenia (> or = 14 days): their graft contents in CD34+ cells, CFU-GM and BFU-E were significantly inferior to those of patients with rapid platelet recovery. Although numbers of infused CD34+ cells and CFU-GM or BFU-E were well correlated, the graft content in CD34+ cells was the only parameter predictive of platelet recovery (r = -0.38, p = 0.04), with a threshold of 2.5 x 10(6) CD34+ cells/kg. However, because rapid platelet reconstitution was obtained for 4 of 16 patients re-infused with < 2.5 x 10(6) CD34+ cells/kg, we investigated whether the graft CFU-MK content might be a better predictor of platelet reconstitution than the CD34+ cell content. Eighteen CD34 grafts were studied for CFU-MK content: CD34 and CFU-MK contents were weakly correlated (r = 0.52, p = 0.03), but there was no correlation between numbers of infused CFU-MK and time to platelet recovery. We conclude that, for autologous CD34 grafts, CFU-MK assays, like CFU-GM or BFU-E assays, cannot be used to predict platelet recovery. A CD34+ cell content > or = 2.5 x 10(6)/kg remains the only reliable indicator of the platelet reconstitution capacity of a CD34 graft.

Ex vivo expansion of hematopoietic progenitors from CD34+ cells selected from leukapheresis products of lymphoma and myeloma patients: feasibility and enhancement by fibronectin.

The feasibility of ex vivo expansion of hematopoietic progenitors selected from leukapheresis products of patients treated for multiple myeloma (MM) was studied and compared with progenitor expansions from patients with nodular non-Hodgkin's lymphoma (NHL) or healthy donors. After positive selection, CD34+ cells from leukapheresis products of 4 MM and 5 NHL patients and CD34+ cells from bone marrow (BM) of 3 healthy donors were grown in IMDM plus 12.5% horse serum, 12.5% fetal calf serum, IL-1alpha, IL-3, IL-6, SCF, GM-CSF, G-CSF (10 ng/ml each), and EP (4 UI/ml). Outputs of CD34+ cell cultures from MM and NHL patients were similar. Day 14 mean increases in CD34+, CFU-GM, and total cell numbers were, respectively, 5.3-fold, 19.8-fold, and 1173-fold for MM patients and 4.3-fold, 15.6-fold, and 1659-fold for NHL patients, with at least 40% of day 14 cells being of granulocytic lineage. Patient CD34+ cell culture output was found to be related to the CFU-GM/CD34+ cell ratio of selected CD34+ cells, not to underlying pathology. When the initial CFU-GM/CD34+ cell ratio was above 0.025, MM and NHL CD34+ cell culture outputs were always above 1000-fold. Moreover, in all but one CD34+ cell culture, the use of fibronectin (FN)-coated dishes improved CFU-GM and total cell expansion. In patient CD34+ cultures carried out in FN-coated dishes, mean day 14 CFU-GM and total cell outputs were increased, respectively, 2.1-fold and 1.9-fold. We conclude that if the CFU-GM/CD34+ cell ratio is sufficient (>0.025), ex vivo expansion of hematopoietic progenitors from CD34+ cells selected from leukapheresis products is possible for both MM and NHL patients and that using FN-coated flasks is a simple and reliable way to improve both CFU-GM and total cell output.

In vitro expansion of CD34+ cells from peripheral blood of myeloma and lymphoma patients.

We studied the feasibility of in vitro expansion of CD34+ cells from patients with multiple myeloma (MM) or follicular non Hodgkin lymphoma (NHL). CD34+ cells were selected from peripheral blood (PB) using avidinbiotin immunoadsorption columns: purified CD34+ cells from three MM and five NHL patients were expanded. First, CD34+ cells (2 MM, 4 NHL) were grown for 14 days in 5 ml of IMDM plus 12.5% horse serum (HS), 12.5% fetal calf serum (FCS) and a commonly used combination of cytokines: IL1alpha, IL3, IL6, SCF, GM-CSF, G-CSF (10 ng/ml each) and EP (4 UI/ml). In these conditions, at day 14, average increase in CD34+, CFU-GM and total cell numbers were, respectively: x 6.0 x 23 and x 2,113 fold with 20 to 35% of granulocytic cells. In terms of CD34+ cell, CFU-GM and total cell outputs, MM cultures were comparable to NHL cultures, but MM cultures seemed to produce less granulocytic cells than NHL cultures. Next, in vitro expansion of PB CD34+ cells was tested in culture media suitable for clinical use. Two cultures (1 MM, 1 NHL) were carried out for 14 days in 20 ml of X-Vivo 10 medium, 2% human serum, IL1alpha, IL3, IL6, SCF, GM-CSF, G-CSF (6 ng/ml each) and EP (2 UI/ml). Increase in CD34+, CFU-GM and total cell numbers in these conditions were, respectively: x 5.7 and x 19.7, x 11.9 and x 40.9, x 424 and x 408 fold, with at least 75% of granulocytic cells in both cultures. We conclude that, although further improvements are necessary, in vitro expansion of PB CD34+ cells can presumably be carried out successfully for MM patients as well as for NHL patients, including in conditions suitable for clinical use.

[Alexander's disease in adults and diffuse cerebral gliomatosis in 2 members of the same family]. / Maladie d'Alexander de l'adulte et gliomatose cérébrale diffuse chez deux membres d'une famille.

A 31-year old woman died after 10 years of progressive dysautonomia and cerebellar and pyramidal symptoms. CT scan showed pontine, bulbar and cerebellar atrophy. Post-mortem examination revealed Rosenthal's fibers widespread throughout the CNS, but especially in the subependymal and perivascular regions. White matter cavitations involving peri-ventricular regions, hilum of dentate nuclei and pons were observed, leading to a diagnosis of adult form of Alexander's disease. At the age of 5, the patient had been operated upon for a chiasmatic tumor. Microscopic examination revealed a pilocytic astrocytoma without Rosenthal's fibers. No complementary radiotherapy had been done. Her mother has been operated upon in 1972, for a high-grade glioma and is still alive 20 years later. This suggests diffuse cerebral gliomatosis. This family history may suggest a relation between these different diseases. They might be the result of a transmissible astrocytic abnormality with varying expression.