[Venous ulcer on lateral edge of foot].
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Biomedical subjects
Publications and source records attributed to T Matthes.
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Sideroblastic anemias are a heterogenous group of disorders characterized by the presence of sideroblasts in the bone marrow aspirate. Current classification schemes distinguish between diseases of the heme synthesis pathway and diseases of other mitochondrial pathways which can either be of primary origin (defects in mitochondrial DNA) or of secondary origin (defects in nuclear DNA). Although several distinct hereditary forms exist, sideroblastic anemias are most frequently acquired diseases and belong to the group of myelodysplastic syndromes with the propensity to develop into overt leukemia. Treatment is mainly supportive (vitamins, blood transfusions, cytokines) and only rarely are bone marrow transplantations performed. The molecular defects of a few hereditary forms have already been elucidated, but the genes involved in the acquired forms are still largely unknown.
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We report on a patient with terbinafine-induced SCLE covering clinical, histopathological and serological findings. Positive serological results included ANA, SS-A (Ro)-antibodies and anti-histone-antibodies with specificity for H1 and H3. The literature on terbinafine-induced SCLE is reviewed. We discuss H1- and H3-specific anti-histone antibodies as a possible diagnostic criterion of drug-induced SCLE.
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Acute normovolaemic haemodilution (ANH) is used to avoid perioperative blood loss and consists of the withdrawal of whole blood just before or just after anaesthesia induction and its simultaneous replacement by synthetic colloids and crystalloid solutions. In an attempt to improve the efficiency of this technique while at the same time avoiding cardiovascular complications, we set up a pilot study to test the association of rHuEpo/ANH during elective surgery for total hip replacement. Five patients (3 males, 2 females) were included in this study. The amount of whole blood drawn was 3 x 450 ml from the men and 2 x 450 ml from the women. Before blood was taken, the mean increase in haemoglobin was 1.2 +/- 0.9 g/dl and mean increase in reticulocytes 106 +/- 34 G/l. No patient received homologous transfusion during the perioperative period; 3 patients received the totality of predonated blood and one patient 2 of the 3 units taken. The mean fall in haemoglobin at day 1 post-surgery was 3.6 g/dl. In conclusion, the stimulation of erythropoiesis by rHuEpo in the pre-surgery phase led on average to a 1 g/dl gain in haemoglobin, permitting an isovolaemic withdrawal of 900 to 1350 ml of blood depending on body weight without the development of severe anaemia. It was thus possible to perform total hip replacement in all the patients without homologous blood support and with a post-surgery haemoglobin value of > 10 g/dl. This protocol should be further tested in a prospective randomised study (rHuEpo versus placebo) in order to assess the real benefit of rHuEpo.
Less is known about the cytokine expression and regulation of normal plasma cells compared to that of activated B cells or myeloma cells. This study shows that nonproliferating (hydroxyurea-treated), immunoglobulin (Ig)-secreting cells generated from human B cells in the EL-4 culture system no longer express interleukin (IL)-6 mRNA, progressively lose IL-10 mRNA, but continue to express transforming growth factor (TGF)-beta 1 mRNA. Secretion of TGF-beta 1 protein was demonstrated. On the other hand, and in contrast to the suppression of B cell proliferation and Ig secretion, the basal or the IL-6/IL-10 stimulated Ig secretion of nonproliferating cells was not inhibited by recombinant TGF-beta 1. Plasma cells isolated from human bone marrow expressed neither IL-6 nor IL-10 mRNA; only TGF-beta 1 mRNA was detected by reverse transcription-polymerase chain reaction analysis. Such plasma cells may be on average more "aged" cells than those generated in vitro. Thus, plasma cells persistently express TGF-beta 1, a known suppressor of various lymphoid and hemopoietic cell activities, but do not limit their own Ig secretion via this cytokine.
While Epstein-Barr virus (EBV)-immortalized B cell lines have been shown to secrete interleukin (IL)-2 after stimulation with either teleocidin or phorbol myristate acetate (PMA) and ionomycin, experimental conditions leading to IL-2 production by normal human B cells have not been reported. In the present study we investigated various B cell activating conditions, including--by analogy to EBV-immortalized B lymphocytes--stimulation of B cells that are already proliferating (in cultures with IL-4 and immobilized anti-CD40 monoclonal antibody; the anti-CD40 system). This approach showed that B lymphocytes secreted IL-2 in the culture medium, but only if they were first activated for more than 24 h in the anti-CD40 system before exposure to PMA plus ionomycin. The production rate of IL-2 by B lymphocytes reached a maximum after 6 days of priming in such cultures followed by 48 h of stimulation with PMA plus ionomycin, corresponding to 7% or 15% of that of fresh CD4+ T cells activated, respectively, with phytohemagglutinin plus PMA, or with PMA plus ionomycin for 48 h. This IL-2 production could not be attributed to T cell contamination nor to EBV-infected B cells according to flow cytometric and reverse transcriptase-polymerase chain reaction analysis of cultured B cells. Lower IL-2 expression (detected only as mRNA synthesis) was also induced in the cultured B lymphocytes after incubation with cross-linking anti-IgM antibodies instead of PMA plus ionomycin. The appearance of IL-13 mRNA, but not IL-4 mRNA, was detected under the same stimulation conditions as for IL-2 mRNA. These results show that the production of IL-2 by normal B lymphocytes occurs as a late event relative to their activation and proliferation, and is in this respect subject to regulation different to that found in T lymphocytes.
SEQ DATA who developed polyclonal hypergammaglobulinaemia: 38.3 milligrams polyclonal IgG, 0.97 milligram IgA and 0.33 milligram IgM. Immunophenotyping showed a monoclonal lymphocytic population CD19+ CD5+ CD40+ CD23+, low sIg+ (95%), kappa type in the great majority (96%). RT-PCR of immunoglobulin genes gave evidence of monoclonal rearrangement of the IgM type. Our tests showed that IL-2 was produced when leukaemic B cells were stimulated with phorbol myristate acetate, ionomycin and lipopolysaccharide. In addition, transfections with the full IL-2 promoter or elements thereof revealed that IL-2 expression is inducible and mediated through the NF-kB-promoter element. Finally, the amount of IL-2 secreted by these cells is about 39 ng/ml/10(6) cells, which is remarkably high for non-T cells. These results suggest that the large amounts of polyclonal IgG seen in this case of B-CLL are secreted by normal B cells which are in turn stimulated by IL-2 produced by proliferating monoclonal (leukaemic) B cells. Under cyclosporin A treatment, immunoglobulin secretion and B cell count remained low.
Quantification of mRNA is important for studies of gene expression and gene regulation. We investigated the utility of the reverse transcriptase polymerase chain reaction (RT-PCR) approach in the quantification of mRNA from small cell numbers. To take into account the complex kinetics of the PCR amplification process and the nonlinear signal development during detection of PCR products, calibration curves were established on the basis of different, known, starting concentrations of cDNA fragments, different PCR cycle numbers, and different signal intensities. Detection of digoxigenin-labeled PCR products via an enzymatically generated chemiluminescent signal was found to give a reproducible and wider range of signal intensities compared to simple ethidium bromide staining. We applied this methodology to the quantification of immunoglobulin M (IgM) mRNA levels in human B cells. Using an in vitro culture system in which B cells differentiate into plasma cells, the kinetics of IgM mRNA expression were established during a 10-day culture period and a 180-fold mRNA increase was found.
Expression of mRNA for eight cytokines was analyzed in an in vitro response-proliferation and Ig-secretion--of normal human B lymphocytes. This was made possible by the use of murine thymoma cells as helper cells in conjunction with human T cell supernatant, and the design of human DNA sequence-specific primers for RT-polymerase chain reaction. mRNAs for interleukin (IL)2 and IL-4, but also for IL-1 alpha and IL-1 beta remained undetectable during the whole culture period in highly purified B cells prepared by a three-step purification protocol. However, tumor necrosis factor alpha and IL-6 mRNAs peaked during days 1-3 after culture start and became undetectable after 5-6 d, shortly before bulk B cell proliferation started to decline. In contrast, transforming growth factor beta 1 mRNA, after a progressive increase during the first few days, and IL-10 mRNA, after a peak on days 1-3, remained detectable in immunoglobulin (Ig)-secreting cultures throughout the observation period of 22 d. Clonal analysis on 8-d cultures that had been seeded with single B cells by autocloning with the cell sorter, revealed that 85% of 77 B cell clones studied, expressed TGF-beta 1 mRNA, and only 19% IL-10 mRNA. These findings show a differentiation stage-related cytokine program during a B cell response, whereby (a) B cells can become activated without IL-1 alpha or IL-1 beta expression; (b) mRNA for positive (IL-10) and negative (TGF-beta 1) autoregulatory factors coexists in cell populations during the later phase of the response, although not necessarily in all B cell clones; and (c) normal Ig-secreting cells cease IL-6 expression in contrast to their malignant counterparts, myeloma cells.
Clones of human B lymphocytes, obtained after immortalization with Epstein-Barr virus (EBV) of single CD19+ B cells and expansion in the absence of human T lymphocytes, produced mRNA for the T cell cytokines interleukin(IL)-2, IL-4, and interferon (IFN)-gamma. As detected by reverse transcriptase-polymerase chain reaction, IL-2 mRNA was expressed only after stimulation with the combination of phorbol 12-myristate 13-acetate (PMA) plus ionomycin. IL-4 mRNA was constitutively detectable in all (10/10) EBV-transformed B cell clones, and the mRNA for IFN-gamma was constitutively present in half of the clones. In contrast to IL-2 mRNA, the expression of IL-4 and IFN-gamma mRNA could be increased by PMA alone. Most of the clones produced IL-2 bioactivity and immunoreactive protein, but neither IL-4 nor IFN-gamma protein secretion was detected. The intriguing question raised by these results is whether IL-2 secretion could contribute to the immune control of EBV-infected B lymphocytes by cytolytic T cells, and whether normal B lymphocytes can potentially be induced to express certain cytokines including IL-4 in response to the appropriate activation signals.
In accordance with results obtained in another culture system, it has previously been shown that human B cells frequently switch to immunoglobulin E (IgE) when they are co-cultured with irradiated mutant EL4 thymoma cells (which provide a CD40 ligand-mediated B cell activation signal), T cell supernatant and recombinant interleukin (IL)-4. However, because of the potentially severe side effects of IgE, such as anaphylaxis, B cells could have a limited capacity to produce this isotype. The IgE secretion rate of plasma cells is not known. In the present study, we compared the secretion rates for different Ig classes by means of limiting dilution analysis of plasmocytic cells that were harvested after 8 to 9 days from primary EL4/B cell cultures and titrated into secondary cultures in the presence of a cell proliferation-blocking concentration of hydroxyurea. These cells secreted Ig at constant rates for periods of up to 2 weeks; IgE secretion was IL-4 independent. The mean cellular secretion rates were similarly high for IgE (150 pg/cell/24 h) and other isotypes (IgM 273 pg, IgG 112 pg, IgA 136 pg/cell/24 h). In terms of molecules per min this represents 3.3 x 10(5) for IgE versus 1.2 x 10(5) for IgM, 3.1 x 10(5) for IgG and 3.6 x 10(5) for IgA. The relative frequency of IgE-secreting cells was only 0.3% of the total number of Ig-secreting cells, suggesting a small size of IgE-producing clones in this in vitro system. Whether this is relevant regarding an in vivo response is not known. Clearly, the Ig secretion capacity of plasma cells would not limit an IgE response in the absence of extrinsic control.
Natural and induced antitubulin antibodies were compared for their epitope recognition on alpha- and beta-tubulin subunits by immunoenzymatic assays and Western blot techniques on partially digested tubulin molecules. Our results indicated that natural autoantibodies recognized different epitopes from those recognized by induced antibodies, because: 1) all polyspecific natural autoantibodies tested so far recognized the same or very overlapping epitopes in the central part of both alpha- and beta-subunits (between positions 100 and 300 on the tubulin amino acid sequence) and that this epitope differed from the various epitopes recognized by induced antitubulin antibodies on the amino-terminal or carboxy-terminal parts of the tubulin subunits; 2) one human myeloma protein (monoclonal (m)IgA, kappa) with a monospecific antitubulin activity bound to an epitope around position 310 on both alpha- and beta-subunits and a second human mIg (mIgM, kappa) with a monospecific anti-beta activity bound to an epitope on the carboxy-terminal part of the subunit around amino acid position 350. Both epitopes differed from epitopes recognized by induced antitubulin antibodies. These results thus confirmed our previous findings indicating that natural and induced antitubulin antibodies do not share cross-reactive idiotopes.
Two monoclonal anti-idiotopic antibodies (anti-Id) were raised in mice against a human monoclonal IgA,K displaying a monospecific anti-tubulin (anti-alpha- and anti-beta-tubulin) activity. One anti-Id (IgG,K) recognized a private idiotope, TID 3.2, present only on the IgA,K immunogen, close to or within the antigen-combining site. The other anti-Id (IgM,K) recognized a recurrent idiotope, TID 7.1, outside the paratope and present in normal human and BALB/c mouse serum, on 2 of 11 polyspecific human monoclonal immunoglobulins and on 6 of 11 murine natural monoclonal auto-antibodies exhibiting a widespread anticytoskeletal protein-binding activity. Both the idiotopes were absent on two induced anti-tubulin antibodies exhibiting a monospecific anti-alpha- and anti-beta-tubulin specificity. Utilizing competitive and additivity immunoassays, we could show that the polyspecific human and mouse anticytoskeletal antibodies tested, whether bearing the TID 7.1 Id or not, appeared to compete in variable degrees for epitopes on the tubulin molecule recognized by the monoclonal IgA,K but distinct from the epitopes recognized by the induced monospecific anti-tubulin antibodies. The high incidence of the recurrent TID 7.1 idiotope in man and mouse suggests an important physiologic and perhaps regulatory function of this idiotope. Furthermore our data suggest that a restricted family of germ-line genes, highly conserved during phylogeny, may encode for these idiotope-bearing Ig molecules.
The methods of statistical physics have been applied to the analysis of cell movement. Human polymorphonuclear leukocytes were exposed to different surfaces possessing parallel oriented physical structures (scratched glass surface, machine drilled aluminum surface, optical grid and stretched polyethylene foil) and cell migration was observed using time-lapse photography. We demonstrate that in cell migration along physical structures, referred to as contact guidance, two subgroups can be distinguished: 1) The nematic type where the cell size is large in relation to the grid distance of the undulate surface. 2) The smectic type where the cell size is small in relation to the grid distance of the substrate. Nematic contact guidance is characterized by an anisotropic random walk. In all substrates investigated the diffusion process parallel to the lines was faster than the diffusion process perpendicular to them. The angular dependent diffusion coefficient was described by an ellipse. Deviation from a circle defined an apolar order parameter, whose value was about 0.3. The amount of information which the cells collected from, the undulate surface was very low, between 0.1 and 0.2 bits. We demonstrate that cells do not recognize all the details of their surroundings and that their migration can be compared to the "groping around" of a short sighted man. The blurred environment can be described by a mean field whose strength is proportional to the apolar order parameter. It is argued that the anisotropic surface tension is the basic source for nematic contact guidance. Smectic contact guidance is characterized by an anisotropic random walk and is quantified by a density order parameter which is 0.28 in the case of the scratched glass surface of a Neubauer counting chamber. The information which the cells collect from their environment is very low (0.03 bits). The lines seen by the cell can be described by a mean field whose strength is proportional to the density oder parameter. Finally, we demonstrate that the locomotion of granulocytes is governed by an internal clock and internal programs. After migrating for a certain time (32 s) in a particular direction, a new direction of locomotion is determined by an internal program. The cell decides basically between left or right, thereby preferring a turn angle such that the cell migrates either parallel or perpendicular to the lines. The angles are nearly equally probable but the cell moves, in the case of nematic guidance, with different velocities in the + or - direction. The cell also has directional memories with characteristic times of 32 s and greater than 100 s.
Polyspecific natural autoantibodies (NAAb) are antibodies present in normal unimmunized animals and are able to react with very dissimilar antigens (Ag). To better delineate the characteristics of polyspecificity, we subjected monoclonal NAAb to four different immunochemical studies: (1) Two-dimensional gel electrophoresis performed on eight NAAb did not reveal any obvious relationship between charge and antigen specificities; (2) NAAb widely polyspecific on proteins and nucleic acid were reactive with lipids bearing either phosphate, sulfate or carboxyl polar groups; (3) pepsin digestion of polyspecific IgM NAAb yielded Fab'2 fragments which maintained their multireactivities, but exhibited a decrease in reactivity as compared to that seen with monospecific mAb (induced); (4) two different assays were used to analyse the complement fixation ability of IgM NAAb. While very weak or no complement fixation was observed with a classical complement fixation test (fluid phase), when a complement enzyme immunoassay was used where Ag is immobilized on a solid phase, polyspecific NAAb fixed reproducible and easily detectable amounts of complement.
Natural autoantibodies (NAAbs) are an important constituent of circulating immunoglobins. Some demonstrate polyspecific reactivity and high idiotypic connectivity. For example, they are reactive with DNA and cytoskeleton protein; others exhibit restricted binding specificity. Among several hypotheses, we have explored the possibility that NAAbs constitute a physiologic system in the organism that participates in the elimination of dead tissues and cellular debris by opsonization and phagocytosis.