Recurrent symmetrical bendings cause dwarfing in Hydrangea through spatial molecular regulation of xylem cell walls

Environmental prejudices progressively lead to the ban of dwarfing molecules in agriculture, and alternatives are urgently required. Mechanical stimulation (MS) is a promising, eco-friendly, and economical technique, but some responses to mechanical stimulation vary from one plant species to another. Additionally, as more frequent and violent wind episodes are forecasted under global climate change, knowledge of plant responses to stimuli mimicking wind sways is decisive for agriculture. However, little is known about plant mechanosensitive responses after long-term, recurrent MS. Here, the effects of 3-week, recurrent, symmetrical bendings (1 or 12 per day) in Hydrangea macrophylla stems are examined. Bendings repressed internode elongation and leaf area development, whereas the diametrical growth of the basal internode is increased. Responses were dose-dependent, and no desensitization was observed during the 3 weeks of treatment. MS was almost as efficient as daminozide for plant dwarfing, and it improved stem robustness. Histological and molecular responses to MS were spatially monitored and were concordant with ongoing primary or secondary growth in the internodes. Our molecular data provide the first knowledge on the molecular paths controlled by mechanical loads in Hydrangea and revealed for the first time the involvement of XYP1 in thigmomorphogenetic responses. MS still had a transcriptional impact 48 h after the last bending session, promoting the expression of XYP1, FLA11, and CAD1 while repressing the expression of EXP3 and XTH33 homologs in accordance with xylogenesis, cell wall thickening, and lignin deposition in the xylem of basal internodes. In upper elongating internodes, repression of XYP1, CAD1, SAMS1, and CDC23 homologs is correlated with ongoing primary, even though stunted, growth. For producers, our findings highlight the potential of MS as a sustainable and economical option for controlling plant compactness in Hydrangea and show valuable reinforcement of stem strength.

Unraveling the dataset transcriptomic response of Hydrangea macrophylla stem to mechanical stimulation: De novo assembly and functional annotation

A crucial attribute of potted ornamental plants is compactness characterized by well branched plants with rather short stems bearing numerous flowers. To gain plant compactness, producers use plant growth regulators (PGRs), in particular growth retardants during culture. However, due to their negative environmental impacts, growth retardants are progressively withdrawn from the market. As a response, eco-friendly alternative methods to chemicals need to be developed. One method consists in mimicking mechanical stimulation (MS) imposed by wind on plants which causes reduction in stem elongation, an increase in stem diameter and an increase in branching, all contributing to plant compactness. So far, few plant species were studied under MS and little is known on molecular response mechanisms to MS. This first transcriptomic data after MS in Hydrangea macrophylla will contribute unravelling how plants respond to mechanical stimuli. RNAseq data were obtained from total mRNA of stems collected 15 min before MS and 1, 3, 24 and 72 h after MS treatment. RNA from non-MS treated plants were used as control. MS treatment consisted in 12 consecutive bendings (i.e. 6 forth and 6 back) applied at 9 a.m. during 1 h and for a single day. From RNAseq data a de novo assembly of the transcriptome was produced and 78,398 transcripts functionally annotated. These transcriptomic data also contribute to a better knowledge of how outdoor crop respond to the increasing frequency of strong harmful winds under climate change.

Biochemical and functional characteristics of stored (double-dose) buffy-coat platelet concentrates treated with amotosalen and a prototype UVA light-emitting diode illuminator

BACKGROUND

Pathogen reduction of platelet concentrates (PCs) using amotosalen and broad-spectrum UVA illumination contributes to the safety of platelet transfusion by reducing the risk of transfusion-transmitted infections. We evaluated the in vitro quality of stored buffy-coat (BC) PCs treated with amotosalen and a prototype light-emitting diode (LED) illuminator.

METHODS

Double-dose BC-PCs collected into PAS-III/plasma or SSP+ /plasma (55/45%) were treated with amotosalen in combination with either conventional UVA lamps (INT100 Illuminator 320-400 nm) or LED illuminators at 350 nm. Platelet quality and function were evaluated over 7 days.

RESULTS

Platelet counts were conserved during storage in all groups, as was platelet swirling without appearance of macroscopic aggregates. Integrin αIIbβ3 and glycoprotein (GP) VI expression remained stable, whereas GPIbα and GPV declined similarly in all groups. UV lamp- and LED-treated PCs displayed similar glucose consumption, lactate generation, and pH variation. Comparable spontaneous and residual P-selectin and phosphatidylserine exposure, activated αIIbβ3 exposure, mitochondrial membrane potential, lactate dehydrogenase release, and adhesive properties under flow conditions were observed during storage. The use of SSP+ /plasma compared with PAS-III/plasma better preserved most of these parameters, especially during late storage, irrespective of the type of illuminator.

CONCLUSION

Replacing the UVA lamp for photochemical treatment by LED illuminators had no impact on platelet metabolism, spontaneous activation, apoptosis or viability, or on the in vitro function of BC-PCs stored for 7 days in SSP+ or PAS-III/plasma. These findings support improved procedures for the pathogen reduction and storage of PCs, to ensure transfusion safety and retention of platelet functional properties.

Matrix stiffness controls megakaryocyte adhesion, fibronectin fibrillogenesis, and proplatelet formation through Itgβ3

Megakaryocytes (MKs) are the precursor cells of platelets, located in the bone marrow (BM). Once mature, they extend elongated projections named proplatelets through sinusoid vessels, emerging from the marrow stroma into the circulating blood. Not all signals from the microenvironment that regulate proplatelet formation are understood, particularly those from the BM biomechanics. We sought to investigate how MKs perceive and adapt to modifications of the stiffness of their environment. Although the BM is one of the softest tissue of the body, its rigidification results from excess fibronectin (FN), and other matrix protein deposition occur upon myelofibrosis. Here, we have shown that mouse MKs are able to detect the stiffness of a FN-coated substrate and adapt their morphology accordingly. Using a polydimethylsiloxane substrate with stiffness varying from physiological to pathological marrow, we found that a stiff matrix favors spreading, intracellular contractility, and FN fibrils assembly at the expense of proplatelet formation. Itgb3, but not Itgb1, is required for stiffness sensing, whereas both integrins are involved in fibrils assembly. In contrast, soft substrates promote proplatelet formation in an Itgb3-dependent manner, consistent with the ex vivo decrease in proplatelet formation and the in vivo decrease in platelet number in Itgb3-deficient mice. Our findings demonstrate the importance of environmental stiffness for MK functions with potential pathophysiological implications during pathologies that deregulate FN deposition and modulate stiffness in the marrow.

Discriminating young platelets on human leukocyte antigen-I expression highlights their extremely high reactivity potential

Background

The platelet population is heterogeneous, with different subsets that differ on the basis of their function and reactivity. An intrinsic factor participating in this difference of reactivity could be the platelet age. The lack of relevant tools allowing a formal identification of young platelets prevents so far to draw solid conclusions regarding platelet reactivity. We recently reported that human leukocyte antigen-I (HLA-I) molecules are more expressed on human young platelets.

Objectives

The aim of this study was to assess platelet reactivity according to their age based on HLA-I expression level.

Methods

Platelet activation was assessed by flow cytometry (FC) for different platelet subsets based on their HLA-I expression. These populations were further cell sorted and their intrinsic properties were determined by FC and electron microscopy (EM). Statistical analyses were performed with GraphPad Prism 5.02 software using two-way ANOVA followed by a Tukey post hoc test.

Results

HLA-I expression level allowed the identification of 3 platelet subpopulations regarding to their age (HLA low, dim, and high). HLA-I was reliable to guide platelet cell sorting and highlighted the features of young platelets in the HLA-I^high population. In response to different soluble agonists, HLA-I^high platelets were the most reactive subset as shown by the level of P-selectin secretion and fibrinogen binding assessed by flow cytometry. Moreover, the highest capacity of HLA-I^high platelets to simultaneously express annexin-V and von Willebrand factor or activated αIIbβ3 after coactivation with TRAP and CRP indicated that the procoagulant feature of platelets was age-related.

Conclusion

The young HLA-I^high population is the most reactive and prone to become procoagulant. These results open up new perspectives to investigate deeply the role of young and old platelets.

Isolation of Mouse Megakaryocyte Progenitors

Bone marrow megakaryocytes are large polyploid cells that ensure the production of blood platelets. They arise from hematopoietic stem cells through megakaryopoiesis. The final stages of this process are complex and classically involve the bipotent Megakaryocyte-Erythrocyte Progenitors (MEP) and the unipotent Megakaryocyte Progenitors (MKp). These populations precede the formation of bona fide megakaryocytes and, as such, their isolation and characterization could allow for the robust and unbiased analysis of megakaryocyte formation. This protocol presents in detail the procedure to collect hematopoietic cells from mouse bone marrow, the enrichment of hematopoietic progenitors through magnetic depletion and finally a cell sorting strategy that yield highly purified MEP and MKp populations. First, bone marrow cells are collected from the femur, the tibia, and also the iliac crest, a bone that contains a high number of hematopoietic progenitors. The use of iliac crest bones drastically increases the total cell number obtained per mouse and thus contributes to a more ethical use of animals. A magnetic lineage depletion was optimized using 450 nm magnetic beads allowing a very efficient cell sorting by flow cytometry. Finally, the protocol presents the labeling and gating strategy for the sorting of the two highly purified megakaryocyte progenitor populations: MEP (Lin^-Sca-1^-c-Kit⁺CD16/32^-CD150⁺CD9^dim) and MKp (Lin^- Sca-1^-c-Kit⁺CD16/32^-CD150⁺CD9^bright). This technique is easy to implement and provides enough cellular material to perform i) molecular characterization for a deeper knowledge of their identity and biology, ii) in vitro differentiation assays, that will provide a better understanding of the mechanisms of maturation of megakaryocytes, or iii) in vitro models of interaction with their microenvironment.

Cytokinins Are Initial Targets of Light in the Control of Bud Outgrowth

Bud outgrowth is controlled by environmental and endogenous factors. Through the use of the photosynthesis inhibitor norflurazon and of masking experiments, evidence is given here that light acts mainly as a morphogenic signal in the triggering of bud outgrowth and that initial steps in the light signaling pathway involve cytokinins (CKs). Indeed, in rose (Rosa hybrida), inhibition of bud outgrowth by darkness is suppressed solely by the application of CKs. In contrast, application of sugars has a limited effect. Exposure of plants to white light (WL) induces a rapid (after 3-6 h of WL exposure) up-regulation of CK synthesis (RhIPT3 and RhIPT5), of CK activation (RhLOG8), and of CK putative transporter RhPUP5 genes and to the repression of the CK degradation RhCKX1 gene in the node. This leads to the accumulation of CKs in the node within 6 h and in the bud at 24 h and to the triggering of bud outgrowth. Molecular analysis of genes involved in major mechanisms of bud outgrowth (strigolactone signaling [RwMAX2], metabolism and transport of auxin [RhPIN1, RhYUC1, and RhTAR1], regulation of sugar sink strength [RhVI, RhSUSY, RhSUC2, and RhSWEET10], and cell division and expansion [RhEXP and RhPCNA]) reveal that, when supplied in darkness, CKs up-regulate their expression as rapidly and as intensely as WL Additionally, up-regulation of CKs by WL promotes xylem flux toward the bud, as evidenced by Methylene Blue accumulation in the bud after CK treatment in the dark. Altogether, these results suggest that CKs are initial components of the light signaling pathway that controls the initiation of bud outgrowth.

Integrin-Alpha IIb Identifies Murine Lymph Node Lymphatic Endothelial Cells Responsive to RANKL

Microenvironment and activation signals likely imprint heterogeneity in the lymphatic endothelial cell (LEC) population. Particularly LECs of secondary lymphoid organs are exposed to different cell types and immune stimuli. However, our understanding of the nature of LEC activation signals and their cell source within the secondary lymphoid organ in the steady state remains incomplete. Here we show that integrin alpha 2b (ITGA2b), known to be carried by platelets, megakaryocytes and hematopoietic progenitors, is expressed by a lymph node subset of LECs, residing in medullary, cortical and subcapsular sinuses. In the subcapsular sinus, the floor but not the ceiling layer expresses the integrin, being excluded from ACKR4⁺ LECs but overlapping with MAdCAM-1 expression. ITGA2b expression increases in response to immunization, raising the possibility that heterogeneous ITGA2b levels reflect variation in exposure to activation signals. We show that alterations of the level of receptor activator of NF-κB ligand (RANKL), by overexpression, neutralization or deletion from stromal marginal reticular cells, affected the proportion of ITGA2b⁺ LECs. Lymph node LECs but not peripheral LECs express RANK. In addition, we found that lymphotoxin-β receptor signaling likewise regulated the proportion of ITGA2b⁺ LECs. These findings demonstrate that stromal reticular cells activate LECs via RANKL and support the action of hematopoietic cell-derived lymphotoxin.

Expression of a surface antigen (MA6) by peripheral blood CD34+ cells is correlated with improved platelet engraftment and may explain delayed platelet engraftment following cord blood transplantation

CD34(+) cell dose provides a measure of hematopoietic tissue that predicts the rate of engraftment upon transplant. It is positively correlated with multiple measures of hematopoietic recovery, including platelet engraftment. Here we identify a subpopulation of CD34(+) cells that coexpress a surface antigen--MA6, which is more positively correlated with platelet engraftment in a clinical setting than CD34(+) alone. The specific identity and function of MA6 remain to be determined, however, it is expressed by primitive megakaryocyte (MK) progenitors, but is lost with differentiation and is not expressed by platelets. Commitment of CD34(+)MA6(+) cells to the MK lineage was confirmed by in vitro assays and their significance in hematopoietic transplantation explored by flow cytometric analysis of cryopreserved samples of granulocyte colony stimulating factor-mobilized peripheral blood progenitor cell (PBPC) products along with a retrospective analysis of platelet engraftment data. Platelet engraftment by day 21 was predicted by receipt of ≥ 6 × 10(6) CD34(+) cells/kg or ≥ 0.3 × 10(6) CD34(+)MA6(+) cells/kg. Subsequent analysis of cord blood (CB) CD34(+) cells revealed <0.2% coexpressed MA6(+), compared to 8% of PBPC CD34(+) cells. This low proportion of CD34(+)MA6(+) cells may be responsible, at least in part, for the delayed platelet engraftment associated with CB transplantation. However, platelet engraftment is markedly improved in recipients of ex vivo-expanded CB. This may be a consequence of an increased proportion of CD34(+)MA6(+) cells present in the ex vivo-expanded product and also suggests that optimizing ex vivo culture conditions to generate CD34(+)MA6(+) cells might further improve platelet engraftment in CB recipients.

Ex vivo fucosylation improves human cord blood engraftment in NOD-SCID IL-2Rγ(null) mice

Delayed engraftment remains a major hurdle after cord blood (CB) transplantation. It may be due, at least in part, to low fucosylation of cell surface molecules important for homing to the bone marrow microenvironment. Because fucosylation of specific cell surface ligands is required before effective interaction with selectins expressed by the bone marrow microvasculature can occur, a simple 30-minute ex vivo incubation of CB hematopoietic progenitor cells with fucosyltransferase-VI and its substrate (GDP-fucose) was performed to increase levels of fucosylation. The physiologic impact of CB hematopoietic progenitor cell hypofucosylation was investigated in vivo in NOD-SCID interleukin (IL)-2Rγ(null) (NSG) mice. By isolating fucosylated and nonfucosylated CD34(+) cells from CB, we showed that only fucosylated CD34(+) cells are responsible for engraftment in NSG mice. In addition, because the proportion of CD34(+) cells that are fucosylated in CB is significantly less than in bone marrow and peripheral blood, we hypothesize that these combined observations might explain, at least in part, the delayed engraftment observed after CB transplantation. Because engraftment appears to be correlated with the fucosylation of CD34(+) cells, we hypothesized that increasing the proportion of CD34(+) cells that are fucosylated would improve CB engraftment. Ex vivo treatment with fucosyltransferase-VI significantly increases the levels of CD34(+) fucosylation and, as hypothesized, this was associated with improved engraftment. Ex vivo fucosylation did not alter the biodistribution of engrafting cells or pattern of long-term, multilineage, multi-tissue engraftment. We propose that ex vivo fucosylation will similarly improve the rate and magnitude of engraftment for CB transplant recipients in a clinical setting.

[Despite corrective measures, will there still be a lack of anaesthetists and intensive care physicians in France by 2020?]

OBJECTIVES

the demographic decline in the Anaesthesia and Intensive Care practitioners predicted for 2020 may bring into question the speciality's vocation, and indeed peri-operative care as a whole in France. The objective of this study is to assess the French Anaesthetist and Intensive Care physicians' demographics in 2010, and predicted numbers for 2020 taking into account recently initiated corrective measures.

METHODS

data originating from the CFAR-SFAR-INED French medical demographics survey(1), the French General Medical Council, and various studies and projections published by the INED and the DREES(2) were collected and analysed. Factors were then identified that were likely to affect personnel numbers, speciality training requirements and the demand for patient care.

RESULTS

french General Medical Council data is the most reliable and reports 9692 Anaesthetists and Intensive Care physicians practising regularly in France on the 1(st) of January 2009. Of those, 9,391 (96.9 %) were practising on the mainland. Personnel growth reduced due to the effect of specialist training selection procedures: the percentage of doctors entering Anaesthesia and Intensive Care training dropped from 12.7 % per year in 1960 to 1.5 % in 1990. Since 2002, personnel in regular practice dropped by 1.1 % per year. Relatively few doctors were leaving the profession, the decrease was due to the reduction in the numbers entering practice: 222 per year on average from 1988 through 2004, compared to 355 per year for the two preceding decades (1971 to 1987). Anaesthetists and Intensive Care physicians are growing older; the average age increased from 42.8 years of age in 1989 to 51 on the 1(st) of January 2009. Further evidence of this trend is that the number of practitioners less than fifty years of age continues to decrease; just 47.5 % in 2005 compared with 80 % in 1989. 5,139 anaesthetists between 50 and 64 years of age will leave the profession before 2020, over half (52.3 %) of the total practising in 2005. Practitioner density increased from 13.1 Anaesthetists and Intensive Care physicians per 100,000 inhabitants in 1989 to 16.2 in January2006. If only those in regular practice are considered, density is stable at 15.3 per 100,000 inhabitants as of 1(st)January2009. The most recent 2009 projections predict a 13 % decrease in the number of practitioners between 2006 and 2015, and a 16 to 20 % decrease by 2020. Initial projections in 1991 and further projections in 1999 predicted 50 % and 35 to 50 % decreases by 2020. Numerous factors could amplify this reduction in the absence of increased training efforts. These factors include population growth (+6 to 7 % by 2020), the increasing health care demands of an ageing population (+15 %), medical progress, the increasing feminisation of the medical workforce, projected retirements and reductions in migratory flows.

CONCLUSION

despite increasing training throughput and increasing medical immigration, Anaesthetists and Intensive Care physicians in France are ageing noticeably and reducing in number. This foreshadows further personnel reductions in the future. A demographic catastrophe may well have been avoided; a more moderate reduction in personnel persists for 2020 with an ongoing risk of numerical inadequacy with respect to needs. This situation justifies a further increase in training throughput, along with adaptations in the provision of care, so as to ensure maintained care standards.

Predictive factors of long-term mortality of persons with tetraplegic spinal cord injury: an 11-year French prospective study

STUDY DESIGN

Longitudinal study with mortality follow-up.

OBJECTIVE

Identify predictive factors for long-term mortality following tetraplegic spinal cord injury (TSCI).

SETTING

The Tetrafigap survey is a multi-centre epidemiological survey on the long-term outcome of persons with TSCI, initiated in France in 1995 with the participation of 35 rehabilitation centres.

METHODS

The mortality follow-up involves 1241 persons with TSCI who were admitted to one of the study rehabilitation units at the initial phase and who completed the initial self-administered questionnaire. There were 226 observed deaths (18.2%) during an 11-year period. Logistic regression methods, with estimates of odds ratios (ORs), incorporating clinical, functional and social participation data were used to determine the factors related to mortality. This was followed by multivariate analysis to determine the best predictive factors for long-term mortality.

RESULTS

Risk of death increases significantly with age but not with the time elapsed since the accident. The risk of death is higher in men. Interestingly, clinical variables are not the best predictors of long-term mortality. Instead, the significant effect of poor social participation (being single, infrequent contact with friends) and functional limitations (full assistance required with dressing or eating) persists after adjustment for other variables.

CONCLUSION

Once the medical situation becomes more stable, factors related to the long-term mortality of persons with TSCI are not exactly identical to those observed in the short acute-phase and during the first year after the accident. Social participation has a significant effect on mortality.

Noninvasive bioluminescent imaging demonstrates long-term multilineage engraftment of ex vivo-expanded CD34-selected umbilical cord blood cells

The use of umbilical cord blood (UCB) grafts for hematopoietic stem cell transplantation (HSCT) is a promising technique that permits a degree of human leukocyte antigen mismatch between the graft and the host without the concomitant higher rate of graft-versus-host disease that would be observed between an adult marrow graft and a mismatched host. A disadvantage to the use of UCB for HSCT is that immune reconstitution may be significantly delayed because of the low stem cell dose available in the graft. Ex vivo expansion of UCB CD34 cells would provide a greater number of stem cells; however, there are persistent concerns that ex vivo-expanded CD34 cells may lose pluripotency and the ability to contribute meaningfully to long-term engraftment. To address this issue, we transduced CD34-selected UCB cells with a lentiviral construct expressing luciferase, and determined homing and engraftment patterns in vivo by noninvasive bioluminescent imaging in sublethally irradiated NOD/SCID/IL-2Rgamma(-/-) (NSG) mice. Graft contribution to multilineage commitment was also confirmed by analysis of primary and secondary transplants by flow cytometry and immunohistochemistry. Our results demonstrate that, other than a mild delay at the onset of engraftment, there were no significant differences in lineage repopulation or in long-term or secondary engraftment between culture-expanded and unexpanded UCB CD34-selected cells. The results suggest that multipotent stem cells can be expanded ex vivo and can contribute meaningfully to long-term hematopoietic engraftment.

A role for pericytes as microenvironmental regulators of human skin tissue regeneration

The cellular and molecular microenvironment of epithelial stem and progenitor cells is poorly characterized despite well-documented roles in homeostatic tissue renewal, wound healing, and cancer progression. Here, we demonstrate that, in organotypic cocultures, dermal pericytes substantially enhanced the intrinsically low tissue-regenerative capacity of human epidermal cells that have committed to differentiate and that this enhancement was independent of angiogenesis. We used microarray analysis to identify genes expressed by human dermal pericytes that could potentially promote epidermal regeneration. Using this approach, we identified as a candidate the gene LAMA5, which encodes laminin alpha5, a subunit of the ECM component laminin-511/521 (LM-511/521). LAMA5 was of particular interest as we had previously shown that it promotes skin regeneration both in vitro and in vivo. Analysis using immunogold localization revealed that pericytes synthesized and secreted LAMA5 in human skin. Consistent with this observation, coculture with pericytes enhanced LM-511/521 deposition in the dermal-epidermal junction of organotypic cultures. We further showed that skin pericytes could also act as mesenchymal stem cells, exhibiting the capacity to differentiate into bone, fat, and cartilage lineages in vitro. This study suggests that pericytes represent a potent stem cell population in the skin that is capable of modifying the ECM microenvironment and promoting epidermal tissue renewal from non-stem cells, a previously unsuspected role for pericytes.

BMP inhibition stimulates WNT-dependent generation of chondrogenic mesoderm from embryonic stem cells

WNT and bone morphogenetic protein (BMP) signaling are known to stimulate hemogenesis from pluripotent embryonic stem (ES) cells. However, osteochondrogenic mesoderm was generated effectively when BMP signaling is kept to a low level, while WNT signaling was strongly activated. When mesoderm specification from ES cells was exogenous factor dependent, WNT3a addition supported the generation of cardiomyogenic cells expressing lateral plate/extraembryonic mesoderm genes, and this process involved endogenous BMP activities. Exogenous BMP4 showed a similar effect that depended on endogenous WNT activities. However, neither factor induced robust chondrogenic activity. In support, ES cell differentiation in the presence of either WNT3a or BMP4 was associated with elevated levels of both Bmp and Wnt mRNAs, which appeared to provide sufficient levels of active BMPs and WNTs to promote the nonchondrogenic mesoderm specification. The osteochondrogenic mesoderm expressed PDGFRalpha, which also expressed genes that mark somite and rostral presomitic mesoderm. A strong WNT signaling was required for generating the mesodermal progeny, while approximately 50- to 100-fold lower concentration of WNT3a was sufficient for specifying axial mes(end)oderm. Thus, depending on the dose and cofactor (BMP), WNT signaling stimulates the generation of different biological activities and specification of different types of mesodermal progeny from ES cells.

Healthy working life expectancies at age 50 in Europe: a new indicator

OBJECTIVES

The absence of disease or disability and active involvement in society are considered as essential dimensions of successful ageing. To assess these concepts, we propose a new indicator the Healthy Working Life Expectancy (HWLE) that associates health status and productive engagement, in order to compare various situations in Europe.

DESIGN

The study population is drawn from the European Community Household Panel (ECHP) which is the unique source of longitudinal data, providing comparable information between 1995 and 2001 on health and work statuses for a sample of some 60,000 household's representative of the population of: Austria, Belgium, Denmark, Finland, France, Germany, the United Kingdom, Greece, Italy, the Netherlands, Portugal, and Spain. Based on the multi-state life table approach conventionally used for calculating healthy life expectancies, the HWLE corresponds to the number of years spent between the ages of 50 and 70 both in good health and at work.

RESULTS

In average, among the 20 years available between age 50 and age 70, the HWLE is 7.5 years for men and 4.8 years for women, ie, one half and one third respectively of the number of years spent in good health (14.1 and 13.5 years). The countries where the healthy working life expectancy of seniors is the highest are also the countries where the levels of employment of seniors are higher. Conversely, health status has only a weak influence on the HWLE indicator.

CONCLUSION

These findings suggest the existence of a reservoir of healthy years which can be used to increase the length of the working life expectancy. They underline also the essential role that employment maintenance and retirement policies should have to increase the number of healthy years spent at work, and therefore guarantee a successful ageing for the seniors in Europe.

Greater bone formation of Y2 knockout mice is associated with increased osteoprogenitor numbers and altered Y1 receptor expression

Germ line or hypothalamus-specific deletion of Y2 receptors in mice results in a doubling of trabecular bone volume. However, the specific mechanism by which deletion of Y2 receptors increases bone mass has not yet been identified. Here we show that cultured adherent bone marrow stromal cells from Y2(-/-) mice also demonstrate increased mineralization in vitro. Isolation of two populations of progenitor cell types, an immature mesenchymal stem cell population and a more highly differentiated population of progenitor cells, revealed a greater number of the progenitor cells within the bone of Y2(-/-) mice. Analysis of Y receptor transcripts in cultured stromal cells from wild-type mice revealed high levels of Y1 but not Y2, Y4, Y5, or y6 receptor mRNA. Interestingly, germ line Y2 receptor deletion causes Y1 receptor down-regulation in stromal cells and bone tissue possibly due to the lack of feedback inhibition of NPY release and subsequent overstimulation of Y1 receptors. Furthermore, deletion of Y1 receptors resulted in increased bone mineral density in mice. Together, these findings indicate that the greater number of mesenchymal progenitors and the altered Y1 receptor expression within bone cells in the absence of Y2 receptors are a likely mechanism for the greater bone mineralization in vivo and in vitro, opening up potential new treatment avenues for osteoporosis.

Demography of French anaesthesiologists. Results of a national survey by the French College of Anaesthesiologists (CFAR) and the French National Society of Anaesthesia and Intensive Care (SFAR), supported by the National Institute for Demographic Studies (INED)

BACKGROUND AND OBJECTIVE

The perception of a looming manpower shortage led the French College of Anaesthesiologists (CFAR) and the French Society of Anaesthesia and Intensive Care (SFAR), with assistance from the National Institute for Demographic Studies (INED), to conduct a national survey of French anaesthesiologists in order to determine precise physician characteristics data, analyse professional practices and project future service provision.

METHODS

The survey was based on self-administered individual questionnaires, approved by the National Committee on Informatics and Freedom (CNIL). The survey was carried out at the end of 1998 among 1484 hospitals (590 public and 894 private), under the supervision of local referees and regional co-ordinators.

RESULTS

Of 9741 anaesthesiologists' posts, 5694 (58%) are in public hospitals, 3569 (37%) in private practice and 478 (5%) in private hospitals within the National Health Service, i.e. the participant au service public hospitalier (PSPH). Complex validation of the results was necessary to account for the missing responses and multiple sites of activity. The survey identified 8876 specialists practising anaesthesia and intensive care in France at the beginning of 1999, including 216 in French overseas territories. This figure is consistent with that published by the Medical Council (Ordre des Médecins) on 1 January 1999, identifying 8950 anaesthesiologists in France, including 234 in the overseas territories. Annual growth in the anaesthesiologist population has fallen from 9% pre-1989 to 0% in 1999. Male anaesthesiologists outnumber females (35.7%). The average age has risen from 42.8 yr in 1989 to 45.9yr in 1999. The age distribution of anaesthesiologists has become bell shaped, reflecting reduced numbers of younger practitioners. There are currently 14.75 anaesthesiologists per 100 000 people (compared to 12.9 in 1989), a figure slightly above the European average, but there is considerable geographical inequality between the north and south of France, with increased concentrations in large cities that contain university hospitals.

CONCLUSIONS

Future service provision must take account of falling numbers of new anaesthesiologists and an increase in retirements, but must also include changes in working practices, such as the European Working Time Directive. If anaesthesia manpower shortages are to be avoided, there must be a restructuring of the work-place, a redefinition of tasks and improved management of working time.

Mesenchymal stem cells

It has become clear that adult mammalian bone marrow contains not one but two ostensibly discrete populations of adult stem cells. The first and by far the most fully characterized are the hematopoietic stem cells responsible for maintaining lifelong production of blood cells. The biological characteristics and properties of the second marrow resident population of stem cells, variously termed bone marrow stromal cells or mesenchymal stem cells, are in contrast much less well understood. In vitro, cultures established from single-cell suspensions of bone marrow from a wide range of mammalian species generate colonies of adherent marrow stromal cells, each derived from a single precursor cell termed a colony-forming unit-fibroblast (CFU-F). Culture conditions have been developed to expand marrow stromal cells in vitro while maintaining the capacity of these cells to differentiate into bone, fat, and cartilage. A significant portion of our current knowledge of this population of cells is based on analysis of the properties of these culture expanded cells, not on the primary colony-initiating cells. In this article, we will focus on methodologies to prospectively isolate stromal progenitors from mouse and human bone marrow and will review current data that suggest stromal progenitors in the bone marrow in situ are associated with the outer surfaces of blood vessels and may share identity with vascular pericytes.

[Anesthesiologists in France. First results of the national survey conducted in 1999 by the French College of Anesthesiologist, The French National Society of Anesthesia and Intensive Care with the scientific support of the National Institute for Demographic Studies]

OBJECTIVES

Fears related to the future of anaesthesia manpower in France have led the French College of Anaesthesiologists (Cfar) and the French Society of Anaesthesia and Intensive Care (Sfar), in scientific partnership with the National Institute for Demographic Studies (Ined), to set-up a national survey among French anaesthetists (MAR) practicing in France, to describe their demographic evolution and to analyse their professional activities.

METHODS

The survey was based on a personal questionnaire, filled by each individual, approved by the National Commission on Informatics and Freedoms (CNIL). The survey was conducted in November 1998, in the 1484 hospitals, public (590) and private (894) where anaesthetics are performed, under the control of local and regional referents.

RESULTS

The anaesthesiologists positions count gave a total of 9741 positions shared between 5694 in public practice (58%), 3569 in private practice (37%) and 478 in private hospitals taking part to the national health service-PSPH (5%). The evaluation of the number of anaesthesiologists from the number of positions has made necessary a methodology of rectification of the survey to take in account the lack of response and the multiple sites of activity. The survey allows an evaluation of around 8876 physicians practising anaesthesia and intensive care in France at the beginning of 1999, among them 216 overseas. This census is in concordance with the count made by the Medical Council--Ordre des médecins--which published a number of 8716 anaesthesiologists in France, and 234 overseas, at the 1st January 1999, corresponding to a total of 8950. The annual demographic growth has felt from 9% per year, before 1989, to reach the level zero, in 1999. The masculinisation of the speciality is growing with a proportion of 35.7% of females, as well as ageing, the overage of age increasing from 42.8 in 1989 to 45.9 years in 1999. The pyramid of ages does not correspond to a growing population but to ageing people due to a decrease of the youngest classes. The medical density of 14.75 anaesthesiologists for 100,000 inhabitants in 1999, compared to 12.9 in 1989, is slightly above the European average, but the geographic distribution is very unequal between north and south, the large cities, centre of a university hospital, and the smaller one even if a reduction of differences is observed. The study and the analysis of professional activities bring important data to take in account side of demographic evolution.

CONCLUSION

The demographic evolution must integrate non-only the reduction of the entries in the speciality, of the retirements, but also the sociological evolutions linked to the working time reduction. The solutions face to the promised shortcut of manpower consist of a reorganisation of the structures, a new definition of tasks and managements, without the possibility to avoid and adjustment of the anaesthesiologists population.

Transplantation of gene-modified human bone marrow stromal cells into mouse-human bone chimeras

Transplantation of BM stromal cells engineered to secrete therapeutic factors could represent a treatment for a large array of hematologic disorders. The aim of this study was to evaluate the susceptibility of human BM stromal cell precursors to retroviral gene transfer, then the ability of those to be transplanted in vivo. We have transduced a recombinant retrovirus encoding the mouse CD2 antigen into STRO-1+ cells selected from adult and fetal BM. Gene-modified stromal cells were injected intravenously into NOD-SCID mice engrafted previously with pieces of human fetal hematopoietic bone. Using nested PCR, transgenic human cells were detected both in the marrow of human bone grafts and in the BM, liver, and spleen of host mice 7 weeks after grafting. These data indicate that BM stromal progenitor cells are targets for retrovirus-mediated gene transfer and can home to hematopoietic tissues on engraftment through the bloodstream of nonconditioned hosts.

Targeted transfection of the IL-3 gene into primary human hematopoietic progenitor cells through the c-kit receptor

We recently showed that an antibody-mediated gene transfer procedure termed antifection can be used for targeted gene delivery into lymphoid cells in vitro and in vivo. We here report that antifection also is effective for targeted gene transfer to immature hematopoietic cells. A human IL3-expressing plasmid was chemically linked to an anti-human CD117 antibody. Delivery of the IL3 plasmid into IL-3-dependent myeloid TF-1 cells (bearing the CD117 antigen) was specific and resulted in the transient proliferation of the targeted cells in the absence of exogenous IL-3. Transfection of primary human CD34+ hematopoietic stem/progenitor cells led to transient production of IL-3 and transient proliferation of the target cells. Interestingly, by using a semisolid progenitor cell assay, we found that transfected primary CD34+ cells were able to generate normal numbers of cell colonies in the absence of exogenous IL-3. Polymerase chain reaction analysis confirmed the presence and expression of the IL-3 transgene in the progenitor-derived colonies. In conclusion, our data show that CD117 is a suitable cell surface target to specifically transfer gene by antifection into primary CD34+ cells and that delivery of IL-3 gene in these cells resulted in the expression of a functional IL-3 able to support cell growth in absence of exogenous cytokine. Thus, antifection may provide new therapeutic modality relying on the transient production of appropriate growth factors acting via autocrine and/or paracrine mechanisms.

Contribution of AIDS to the general mortality in Central Africa: evidence from a morgue-based study in Brazzaville, Congo

OBJECTIVE

To accurately measure AIDS-related mortality relative to other causes and its impact on life expectancy in Brazzaville, Congo.

DESIGN

Investigation of all deaths during a 1-month period in Brazzaville.

METHODS

From 10 July to 9 August 1996, all bodies handled by Brazzaville's three morgues were examined by a physician. Relatives were interviewed on the circumstances of death, while additional clinical data were gathered from hospital files. Blood samples were systematically drawn from the bodies in two of the three morgues and tested for HIV antibodies.

RESULTS

Amongst the 756 bodies examined at the three morgues, 149 (19.7%) AIDS cases were identified. HIV-1 prevalence was 26.2% (38 out of 145) amongst the subjects in the two morgues where HIV serology was systematically performed. AIDS was the leading cause of death in adults (age > or = 15 years), with 25.1% (122 out of 487) of the adults diagnosed with AIDS. The proportion of adult female AIDS cases was significantly higher than the proportion of male cases (30.2 versus 21.0%; P < 0.05). Moreover, female AIDS cases were significantly younger than male cases (median age, 32 versus 42 years; P < 0.00001). Overall AIDS mortality rate amongst adults was 2.8 per 1000 for men and 3.2 per 1000 for women. The impact of AIDS on life expectancy at birth is 4.3 years for women and 3.3 years for men.

CONCLUSION

Our study provides a direct measure of AIDS contribution to mortality relative to other causes, using a rapid, low cost, reliable and replicable method. Clearly, the impact of AIDS is strongest on female life expectancy.

Transplantation of stromal cells transduced with the human IL3 gene to stimulate hematopoiesis in human fetal bone grafts in non-obese, diabetic-severe combined immunodeficiency mice

The non-obese diabetic-severe combined immunodeficiency (NOD-SCID) mouse is a convenient host for human hematopoietic tissues and cells. Human fetal bone fragments engrafted subcutaneously in NOD-SCID mice sustain human hematopoiesis for several months. MS5 murine bone marrow stromal cells were transfected by electroporation with a plasmid containing the human interleukin-3 gene. As expected, stably transfected hu-IL3-MS5 cells supported human hematopoiesis in vitro more efficiently than MS5 cells. hu-IL3-MS5 cells were then injected intravenously into hu-NOD-SCID mice to test their ability to home to the mouse and/or human bone marrow, and to evaluate the role of hu-IL3 secretion on human hematopoiesis in vivo. hu-IL3 was detected in the mouse serum for up to an observation time of 8 weeks. hu-IL3-MS5 cells engrafted the bone marrow, spleen, liver and lungs of the mice but also the human bone graft. The presence of hu-IL3-MS5 cells in the human bone significantly stimulated local human hematopoiesis. This setting could be used to model the bone marrow homing of intravenously injected stromal cells or stromal cell precursors. The same experimental principle could also be applied in a therapeutic perspective to malignant human bone marrow hematopoiesis.

Functional studies of maturing myeloid cells during ex vivo expansion for treatment of aplasia: feasibility of ex vivo expansion from cryopreserved bone marrow cell samples

Ex vivo expanded CD34+ progenitor cells from fresh or cryopreserved primate bone marrow, induced to granulocytic differentiation with growth factors, were investigated to determine whether myeloid cells produced in liquid cultures have the normal biologic functions needed for the treatment of patients with neutropenia following high-dose chemotherapy or therapeutic or accidental radiation exposure. Human and simian (baboons or macaques) CD34+ cells were cultured with granulocyte-colony stimulating factor (G-CSF), stem cell factor (SCF), interleukin-1 (IL-1), IL-3, and IL-6, and assessed at 14 days of culture for their capacity to respond to different functional tests. Immunostaining revealed that human ex vivo expanded cells contained myeloperoxydase (MPO, 82% +/- 8%) and lactoferrin (LF, 30% +/- 6%) in their granules. Maturation of cultured cells was associated with stimulated chemotactic responsiveness and respiratory burst activity (superoxide anion and hydrogen peroxide production) in expansions from human, baboon, and macaque CD34+ progenitor cells. Mature cells obtained from ex vivo expansion of selected cryopreserved human bone marrow CD34+ cells presented reduced but significant functional activities (chemotactic responsiveness and hydrogen peroxide production) when compared with human peripheral blood neutrophils. The validation of nonhuman primate ex vivo expansion systems may permit their use as models of irradiation. The feasibility of ex vivo expansion from cryopreserved bone marrow cell samples may offer considerable opportunity for banking bone marrow for autologous transfusion.

Characterization of prosomes in human lymphocyte subpopulations and their presence as surface antigens

Prosomes, also called "multicatalytic proteinase" (MCP) or "proteasomes," are a new type of ubiquitous RNP particle present in some archeobacteria and in all eukaryotic cells tested from yeast to human. They were discovered as subcomplexes of untranslated messenger-ribonucleoproteins (mRNP) and later found to have a MCP activity putatively involved in antigen processing. Being composed of variable sets of characteristic proteins and associating small RNAs (pRNA), families of individual "mosaic" prosome particles seem to characterize the differentiation type and physiological state of individual cells and tissues. Here, prosomes from human lymphocytes, isolated and characterized biochemically and by Western blot analysis, were found to differ in their subunit composition compared to other human prosomes. Surprisingly, prosomal antigens were discovered at the outer surface of blood cells monitored by flow cytometry with monoclonal antibodies to individual prosomal proteins. It was observed that human T and B lymphocytes have variable and characteristic prosomal antigens at their surface according to their CD classification. Interestingly, the lymphocyte subpopulations most strongly labeled by the anti-p25K and anti-p27K mAbs were the NK and B cells.

How reporting delay, duration of follow-up and number of cases affect the estimates of the incubation time of transfusion-associated AIDS cases

The authors discuss the impact of reporting delay, duration of follow-up, and number of cases in a sample on estimates of the incubation time of transfusion-associated AIDS cases. "This article comes to the conclusion that the accuracy of the incubation time estimate would depend on the sample size rather than on the duration of follow-up." (SUMMARY IN FRE)

Incubation time for AIDS from French transfusion-associated cases

Although incubation time is a key parameter of the epidemiology of AIDS, statistical estimates based on transfusion-associated AIDS cases have, up to now, used only the single dataset provided by the AIDS program of the Centers for Disease Control (CDC) in Atlanta. Using a new dataset provided by the Direction Générale de la Santé (DGS), of the French Ministry of Health1, we estimate the mean incubation time for AIDS (median in brackets) to be 5.3 years (5.3 years) with a 90% confidence interval ranging from 4.4 to 8.9 years (4.4 to 8.8 years), when a Weibull distribution is postulated for incubation time. The previously encountered problem of very large confidence intervals (range larger than 100 years), is not observed, indicating that an accurate estimate for mean incubation time will be obtainable in the near future.