Proliferating dendritic cell progenitors in human blood.

CD34+ cells in human cord blood and marrow are known to give rise to dendritic cells (DC), as well as to other myeloid lineages. CD34+ cells are rare in adult blood, however, making it difficult to use CD34+ cells to ascertain if DC progenitors are present in the circulation and if blood can be a starting point to obtain large numbers of these immunostimulatory antigen-presenting cells for clinical studies. A systematic search for DC progenitors was therefore carried out in several contexts. In each case, we looked initially for the distinctive proliferating aggregates that were described previously in mice. In cord blood, it was only necessary to deplete erythroid progenitors, and add granulocyte/macrophage colony-stimulating factor (GM-CSF) together with tumor necrosis factor (TNF), to observe many aggregates and the production of typical DC progeny. In adult blood from patients receiving CSFs after chemotherapy for malignancy, GM-CSF and TNF likewise generated characteristic DCs from HLA-DR negative precursors. However, in adult blood from healthy donors, the above approaches only generated small DC aggregates which then seemed to become monocytes. When interleukin 4 was used to suppress monocyte development (Jansen, J. H., G.-J. H. M. Wientjens, W. E. Fibbe, R. Willemze, and H. C. Kluin-Nelemans. 1989. J. Exp. Med. 170:577.), the addition of GM-CSF led to the formation of large proliferating DC aggregates and within 5-7 d, many nonproliferating progeny, about 3-8 million cells per 40 ml of blood. The progeny had a characteristic morphology and surface composition (e.g., abundant HLA-DR and accessory molecules for cell-mediated immunity) and were potent stimulators of quiescent T cells. Therefore, large numbers of DCs can be mobilized by specific cytokines from progenitors in the blood stream. These relatively large numbers of DC progeny should facilitate future studies of their Fc epsilon RI and CD4 receptors, and their use in stimulating T cell-mediated resistance to viruses and tumors.

Simplified structure of a new model to describe urinary excretion of plutonium after systemic, liver or pulmonary contamination of rats associated with Ca-DTPA treatments.

This study validates, by targeted experiments, several modeling hypotheses for interpretation of urinary excretion of plutonium after Ca-DTPA treatments. Different formulations and doses of Ca-DTPA were administered to rats before or after systemic, liver or lung contamination with various chemical forms of plutonium. The biokinetics of plutonium was also characterized after i.v. injection of Pu-DTPA. Once formed, Pu-DTPA complexes are stable in most biological environments. Pu-DTPA present in circulating fluids is rapidly excreted in the urine, but 2-3% is retained, mainly in soft tissues, and is then excreted slowly in the urine after transfer to blood. Potentially, all intracellular monoatomic forms of plutonium could be decorporated after DTPA internalization involving slow urinary excretion of Pu-DTPA with half-lives varying from 2.5 to 6 days as a function of tissue retention. The ratio of fast to slow urinary excretion of Pu-DTPA depends on both plutonium contamination and Ca-DTPA treatment. Fast urinary excretion of Pu-DTPA corresponds to extracellular decorporation that occurs beyond a threshold of the free DTPA concentration in circulating fluids. Slow excretion corresponds mostly to intracellular decorporation and depends on the amount of intracellular DTPA. From these results, the structure of a simplified model is proposed for interpretation of data obtained with Ca-DTPA treatments after systemic, wound or pulmonary contamination by plutonium.

In vitro complement binding on cytoplasmic structures in normal human skin: immunoelectronmicroscopic studies.

We have previously provided evidence that suggests that exposure of cryostat skin sections to normal human serum (NHS) results in the antibody-independent Clq binding to cytoplasmic structures of various cell types, leading to classical complement pathway activation as evidenced by cytoplasmic C3 deposition. In the present study, we have employed immunoelectronmicroscopic methods to clarify the exact nature of cytoplasmic C3 binding structures. Incubation of cryostat skin sections with NHS followed by peroxidase-labeled rabbit anti-human C3 serum (HRP-R/Hu C3) revealed that intracytoplasmic binding of C3 occurred in suprabasal keratinocytes, melanocytes, fibroblasts, smooth muscle cells, endothelial cells, pericytes, Schwann cells, and nerve axons, but not in basal keratinocytes, Langerhans cells, and other cellular constituents of the skin. C3 binding, as revealed by the deposition of HRP reaction product, was exclusively confined to intermediate-sized filaments (ISF), which can therefore be considered to represent the subcellular site for classical complement pathway activation. Under experimental conditions that do not allow classical complement pathway activation, ISF were not decorated. Our observation that ISF of ontogenetically different cell types share the capacity of complement fixation is in accordance with the recent finding that different ISF types, despite their biochemical and antigenic heterogeneity, have common alpha-helical domains and may provide a clue to the mechanism and site of interaction between complement components and ISF.

Increased pachyonychia congenita severity in patients with concurrent keratin and filaggrin mutations.

Pachyonychia congenita (PC), a rare autosomal-dominant keratin disorder caused by mutations in keratin genes KRT6A/B, KRT16 or KRT17, is characterized by painful plantar keratoderma and hypertrophic nail dystrophy. Loss-of-function mutations in the filaggrin (FLG) gene underlie the most prevalent skin disorder of cornification, ichthyosis vulgaris (IV), which presents with generalized scaling and is also associated with atopic dermatitis. Recently, FLG mutations have been reported to increase phenotype severity of X-linked ichthyosis and alopecia areata. We report a parent-child trio in which the mother and the son have PC and the father has IV. Both the mother and the son are carriers for the KRT16 mutation p.Leu132Pro. The son, who is much more severely affected than his mother, in addition carries the heterozygous FLG mutation p.R2447X, which was inherited from the father. This observation suggests that coinheritance of mutations in KRT16 and FLG may aggravate the PC phenotype and that FLG could serve as a genetic modifier in PC.

In vitro and in vivo assessment of plutonium speciation and decorporation in blood and target retention tissues after a systemic contamination followed by an early treatment with DTPA.

This study identifies the main sources of systemic plutonium decorporated in the rat after DTPA i.v. at the dose recommended for humans (30 mumol kg(-1)). For this purpose, standard biokinetic approaches are combined to plasma ultrafiltration for separation of plutonium complexes according to their molecular weight. In vitro studies show that at the recommended DTPA dose, less than 5% of the plasma plutonium of contaminated rats can be displaced from high-molecular-weight ligands. After i.v. administration of Pu-DTPA, early ultrafiltrability of plutonium in plasma decreases with total DTPA dose, which is associated with an increase in plutonium bone retention. This demonstrates the instability of Pu-DTPA complexes, injected in vivo, below the minimal Ca-DTPA dose of 30 mumol kg(-1). Plutonium biokinetics is compared in rats contaminated by plutonium-citrate i.v. and treated or not with DTPA after 1 h. No significant decrease in plasma plutonium is observed for the first hour after treatment, and the fraction of low-molecular-weight plutonium in plasma is nearly constant [5.4% compared with 90% in Pu-DTPA i.v. (30 mumol kg(-1)) and 0.7% in controls]. Thus plutonium decorporation by DTPA is a slow process that mainly involves retention compartments other than the blood. Plutonium-ligand complexes formed during plutonium deposition in the retention organs appear to be the main source of decorporated plutonium.

Direct lung delivery of a dry powder formulation of DTPA with improved aerosolization properties: effect on lung and systemic decorporation of plutonium.

DTPA, an actinide chelating agent, has demonstrated its ability to complex plutonium (Pu) and to facilitate its urinary excretion after internal contamination. This process, known as decorporation is crucial to diminish the burden of Pu in the body. The ability to deliver a chelating agent directly to the alveolar region may increase its local concentration as compared to systemic delivery and therefore increase the extent of decorporation. Second, inhalation offers the potential for needle-free, systemic delivery of small molecules and would be convenient in case of nuclear accident as a first pass emergency treatment. To benefit from the improvement of inhalation technology, we have formulated DTPA into porous particles by spray-drying with dl-Leucine, DPPC and ammonium bicarbonate. The optimized particles possess a volume mean geometric diameter around 4.5 mum and crumpled paper morphology. The in vitro aerodynamic evaluation shows that about 56% of the powder should deposits in the lungs, with about 27% in the alveolar region, an improvement as compared with the micronized powder available with the Spinhaler. After pulmonary administration to rats contaminated with PuO(2), a 3-fold increase of the Pu urinary excretion was observed, but the dissolution of PuO(2) in the lungs was not enhanced.

Uncertainties in doses calculated according to ICRP recommendations after inhalation of 239PUO2 and early chest monitoring.

This study estimates uncertainties in Pu biokinetics and effective doses calculated after an acute inhalation exposure to 239PuO2 according to ICRP recommendations (default values for aerosols size and PuO2 dissolution parameters). This was performed using the most recently reported variations in model parameters and simulations after a Monte Carlo approach. Without chest monitoring, uncertainties in thoracic retention and plutonium excretion was 8-10 (95% confidence interval as the ratio between 97.5 and 2.5 percentiles of the lognormal distributions) up to 900 d after exposure. Early chest monitoring reduces significantly the uncertainties in plutonium biokinetics and doses which remain within a 95% confidence interval of 2.3 as compared with 6.6, without monitoring. Analysis of bioassay data previously reported shows that the dose delivered to some individuals can be out of the confidence interval, which was mostly due to an inhibition of the late mechanical clearance of the alveolar interstitium.

The distribution of the number of alpha hits per target cell: a new parameter to improve risk assessment for cancer induction using ICRP models.

Doses are calculated from the total energy deposited within the different target regions of the organism. After inhalation exposure, only a few particles can be deposited within the respiratory tract that induces a heterogeneous dose distribution. A decrease in risk for lung tumours induction associated to the presence of hot spots has been reported. This was partly explained by a decrease in the transformation rate per gray when cells received more than one alpha hit. This study provides an estimate of the distribution of alpha hits per target cell of the extra thoracic region (ET2), after inhalation exposure to 238UO2, 239PuO2 or 238PuO2, obtained by a stochastic application of the biokinetic and dosimetric ICRP models. After exposure to one annual limit of intake, homogeneous irradiation of the target cells is observed for 238UO2, whereas, for PuO2, most of the dose is due to cells receiving daily tens or even hundreds of alpha hits. This underlines the uncertainties in risk assessment associated with a dose rate effect.

Uncertainties in committed equivalent doses to the thyroid after ingestion or inhalation of different chemical forms of 125-129-131I.

The aim of this study is to reanalyse uncertainties in committed equivalent doses to the thyroid after ingestion of 125-129-131I using the last variability reported for anatomical and physiological parameters of the different ICRP age groups, and to estimate uncertainties after inhalation exposure to different chemical forms of iodine (elemental and organic iodine vapours, iodine loaded particles (study limited to workers for activity median aerodynamic diameters of 1 and 5 microm)). The 95% confidence interval appears in the range of 7-18 (ratio of 97.5 versus 2.5 percentile values of the log-normal distribution: GSD4). The largest uncertainties are observed for 129I which is due to its long half-life. Because of the small range of beta rays of 125-129I when compared with that of 131I, and the preferential location of iodine within the colloid of the thyroid follicles, the use of calculated doses for a realistic risk assessment is discussed.

Limits of DPUI application associated with the number of particles within actinide aerosols.

Dose per unit intake (DPUI) of radionuclides is obtained using International Commission on Radiological Protection (ICRP) models. After inhalation exposure, the first model calculates the fraction of activity deposited within the different regions of the respiratory tract, assuming that the aerosol contains an infinite number of particles. Using default parameters for workers, an exposure to one annual limit of intake (ALI) corresponds to an aerosol of 239PuO2 containing approximately 1 x 10(6) particles. To reach such an exposure, very low particle number might be involved especially for compounds having a high specific activity. This study provides examples of exposures to actinide aerosols for which the number of particles is too low for a standard application of the ICRP model. These examples, which involve physical studies of aerosols collected at the workplace and interpretation of bioassay data, show that the number of particles of the aerosol can be the main limit for the application of DPUI after inhalation exposure.

Modelling of bioassay data from a Pu wound treated by repeated DTPA perfusions: biokinetics and dosimetric approaches.

The aim of this study is to model plutonium (Pu) excretion from the analysis of a well-documented Pu wound case involving repeated diethylene-triamine-penta-acetic acid (DTPA) perfusions up to 390 d and monitoring up to 3109 d. Three modelling approaches were simultaneously applied involving: (1) release of soluble Pu from the wound, estimated with the ICRP66 dissolution model, (2) systemic behaviour of Pu by using ICRP67 model, but also two new models recently reported and (3) additional 'Pu-DTPA' compartments which transfer Pu directly to urinary compartment from blood, interstitial fluids and liver. The best fit of simulations to biological data was obtained by using the new Leggett's systemic model and assuming the presence of three DTPA compartments. Calculations have shown that DTPA treatments have contributed to a 3-fold reduction of the effective dose. Thus, reduction of doses associated with the DTPA treatments can be estimated by modelling which is useful to improve the efficacy of a DTPA treatment schedule based on a diminution of risk.

Decorporation of plutonium by pulmonary administration of Ca-DTPA dry powder: a study in rat after lung contamination with different plutonium forms.

This study evaluates the decorporation efficacy of a pulmonary administration of a new Ca-DTPA (diethylenetriaminepentaacetic acid) dry powder (18 micromol kg(-1) of body mass) after pulmonary contamination of rats with different Pu compounds. After inhalation of PuO2, a delayed intratracheal administration of DTPA cannot reduce significantly the retention of Pu in the lungs but limits its transfer in liver and skeleton. After pulmonary contamination by Pu nitrate, early insufflation of the DTPA powder appears twice as more efficient than an i.v injection of DTPA (30 micromol kg(-1)) to reduce Pu retention in the lungs and is as effective as i.v. injection to limit the extrapulmonary deposit. In contrast, a delayed administration of DTPA cannot reduce the lung or extrapulmonary retention. In conclusion, the improvement of aerodynamic properties of DTPA powder leads to an increase of DTPA amount deposited in the lungs and enhances the body decorporation.

MEDOR, a didactic tool to support interpretation of bioassay data after internal contamination by actinides.

A didactic software, MEthodes DOsimètriques de REférence (MEDOR), is being developed to provide help in the interpretation of biological data. Its main purpose is to evaluate the pertinence of the application of different models. This paper describes its first version that is focused on inhalation exposure to actinide aerosols. With this tool, sensitivity analysis on different parameters of the ICRP models can be easily done for aerosol deposition, in terms of activity and particle number, actinide biokinetics and doses. The user can analyse different inhalation cases showing either that dose per unit intake cannot be applied if the aerosol contains a low number of particles or that an inhibition of the late pulmonary clearance by particle transport can occur which contributes to a 3-4 fold increase in effective dose as compared with application of default parameters. This underlines the need to estimate systematically the number of deposited particles, as well as to do chest monitoring as long as possible.

Thrombin generation in factor VIII-depleted neonatal plasma: nearly normal because of physiologically low antithrombin and tissue factor pathway inhibitor.

BACKGROUND: Bleeding in hemophilic neonates has a low incidence. A possible explanation for this could be the peculiarities of the neonatal hemostatic system, especially low levels of the inhibitors tissue factor pathway inhibitor (TFPI) and antithrombin (AT). OBJECTIVE: We investigated the influence of an elevation of these inhibitors to adult levels on the thrombin generation (TG) in normal neonatal plasma and factor (F) VIII-depleted neonatal plasma by means of incubation with anti-FVIII-antibodies. PATIENTS/METHODS: TG was measured after activation with low amounts of tissue factor (TF) by using Calibrated Automated Thrombography. RESULTS: TG in FVIII-depleted neonatal plasma was nearly as high as in normal neonatal plasma. TG decreased after elevation of AT in both neonatal plasmas. After elevation of TFPI TG decreased much more in FVIII-depleted neonatal plasma than in normal neonatal plasma. After elevation of both inhibitors their synergistic effect led to a stronger decrease of TG in FVIII-depleted neonatal plasma. TG measured in plasma of one hemophilic newborn showed the same pattern as in FVIII-depleted neonatal plasma. CONCLUSION: Our observation provides a biochemical basis for the rare bleeding in hemophilic neonates and shows the important role of the natural inhibitors in the hemostatic system of hemophilic patients.

Uncertainties in aerosol deposition within the respiratory tract using the icrp 66 model: a study in workers.

This study estimates uncertainties in aerosol deposition within the main regions of the human respiratory tract calculated using the ICRP 66 model. Uniform, triangular, normal, or lognormal distributions were assigned to the model parameters, which involve physical properties of aerosols, their inhalability, their thermo- and aerodynamic deposition efficiencies, and the anatomy, physiology, and exertion level of the individuals. Calculations were performed over a range of aerosol sizes from 0.01 to 50 mum. Monodispersed aerosols were characterized by their aerodynamic diameter (dae). Polydispersed aerosols were characterized by their activity median aerodynamic diameters (AMADs) and the geometric standard deviation (GSD) in diameter. Lognormal distributions of particle deposition were generally observed with low GSD (< 2). The highest uncertainties were observed within the deep lung for the smallest and the largest aerosol sizes, which were mainly due either to particle density or to aerodynamic deposition efficiencies and anatomical and physiological variability, respectively. In the case of diameters larger than 5 mum, uncertainties in the deep lung deposition were much more important for monodispersed than for polydispersed aerosols. This was explained both by the size distribution of the deposited aerosol, the median of which corresponded to a maximal dae value of about 7 and 5 in bronchioles and alveoli, respectively, and by the absence of deposition, which occurs for dae equal to or larger than 50 mum, depending on the exertion level. Thus, in the range of AMADs considered, for the four default workers proposed by ICRP 66, uncertainties in aerosol deposition remain low, with GSD smaller than 3.

[Xanthoma disseminatum: a rare case involving the upper extremity]. / Xanthoma disseminatum -- ein seltener Befall an der oberen Extremität.

We describe a dramatic case of class II non-Langerhans cell histiocytosis, xanthoma disseminatum, in a 30-year-old male patient with progressive involvement of the skin, vocal cords, eyes, bones and nerves in spite of chemotherapy with Vespesid and immunotherapy with interferon-gamma. At the age of 43 years, the patient required surgical clearance of airways, eyelids and peripheral nerves, but at present exhibits stable disease on a combination of lipid-lowering drugs including thiazolidinedione.

Design and functionalities of the MADOR® software suite for dose-reduction management after DTPA therapy.

A software suite on biokinetics of radionuclides and internal dosimetry intended for the occupational health practitioners of nuclear industry and for expert opinions has been developed under Borland C++ Builder™. These computing tools allow physicians to improve the dosimetric follow-up of workers in agreement with the French regulations and to manage new internal contaminations by radionuclides such as Pu and/or Am after diethylene triamine penta-acetic acid treatments. In this paper, the concept and functionalities of the first two computing tools of this MADOR(®) suite are described. The release 0.0 is the forensic application, which allows calculating the derived recording levels for intake by inhalation or ingestion of the main radioisotopes encountered in occupational environment. Indeed, these reference values of activity are convenient to interpret rapidly the bioassay measurements and make decisions as part of medical monitoring. The release 1.0 addresses the effect of DTPA treatments on Pu/Am biokinetics and the dose benefit. The forensic results of the MADOR(®) suite were validated by comparison with reference data.

Adjuvant interferon alfa-2a treatment in resected primary stage II cutaneous melanoma. Austrian Malignant Melanoma Cooperative Group.

PURPOSE: Patients with primary cutaneous melanoma with a Breslow thickness > or = 1.5 mm have only a 30% to 70% probability of survival after surgery, and no adjuvant therapy has so far improved this outcome. Since interferon alfa-2a (IFNalpha2a) exhibits antitumor activity in metastatic melanoma, we investigated whether adjuvant IFNalpha2a diminishes the occurrence of metastases and thus prolongs disease-free survival in melanoma patients after excision of the primary tumor. PATIENTS AND METHODS: In a prospective randomized study, 311 melanoma patients with a Breslow thickness > or = 1.5 mm were assigned to either adjuvant IFNalpha2a treatment (n = 154) or observation (n = 157) after excision of the primary tumor. IFNalpha2a was given daily at a dose of 3 mIU subcutaneously (s.c.) for 3 weeks (induction phase), after which a dose of 3 mIU s.c. three times per week was given over 1 year (maintenance phase). RESULTS: Prolonged disease-free survival was observed in patients treated with IFNalpha2a versus those who underwent surgery alone. This difference was significant (P = .02) for all patients enrolled onto the study (intention-to-treat analysis) at a mean observation time of 41 months. Subgroup analysis showed that Breslow tumor thickness had no influence on treatment results in the groups of patients investigated. CONCLUSION: Adjuvant IFNalpha2a treatment diminishes the occurrence of metastases and thus prolongs disease-free survival in resected primary stage II cutaneous melanoma patients.

Mechanism of allergic cross-reactions--II. Cross-stimulation, by chemically unrelated ligands, of rat basophilic leukemia cells sensitized with an anti-DNP IgE antibody.

Serotonin release from rat basophilic leukemia (RBL) cells, sensitized with a DNP-binding monoclonal IgE, was stimulated with solid surface (polystyrene)-bound DNP-amino acids. The stimulatory potency of DNP-amino acids was dependent on the structure of amino acid attached to DNP. Generally, DNP-amino acids with high affinities to the sensitizing IgE (I(50) less than 10 microM) were stimulatory in polystyrene-bound form; DNP-amino acids with lower affinities (Pro, Cys, Trp), and aliphatic aromatic DNP-amino acid derivatives were inactive. In addition to structural analogues of DNP, lymecycline, that is chemically unrelated to DNP but was found to have high affinity to IgE(aDNP), was also stimulatory in this system. This drug, and various quinones (e.g. acenaphthene-quinone) in BSA-conjugated forms also stimulated serotonin release from RBL cells sensitized with IgE(aDNP). These studies suggest that (1) There is a threshold of intrinsic ligand binding affinities at approximately I(50) = 10-100 microM; ligands with lower affinities do not stimulate mediator release even if they are presented in multivalent forms; (2) The above affinity threshold for mediator cell stimulation is valid for various ligands, irrespective of their chemical similarity to the immunogen; (3) Multispecific stimulation of mediator release may contribute to the frequently observed allergic cross-reactions, false positive tests for allergies, and anaphylactic reactions to drugs upon first exposure.