[Necrotic leg ulcers induced by vitamin K antagonists: five cases]. / Ulcères de jambe nécrotiques induits par les anti-vitamines K : à propos de cinq cas.

BACKGROUND: Vitamin K antagonists (VKAs) are widely used in thromboembolic diseases. We report five cases of necrotic leg ulcers having a particularly severe course and in which withdrawal of VKA treatment alone enabled healing. CASE REPORTS: Five patients presented with necrotic leg ulcers clinically evocative of necrotic angiodermatitis or vasculitis. Histological features were variable, including inconstantly inflammatory lesions (leukocytoclastic vasculitis) and microthrombosis. None of the patients had laboratory signs of autoimmune disease. Healing occurred in all patients only after withdrawal of VKA therapy (fluindione or acenocoumarol). Associated vascular diseases included superficial venous, distal arterial insufficiency and postphlebitic disease. In three cases, thrombotic factors were observed: hyperhomocysteinaemia or heterozygous Factor V Leiden mutation. DISCUSSION: Although the causative role of VKAs is based solely on chronological criteria, this potential side effect deserves publication because of its practical therapeutic consequences. The physiopathological mechanisms accounting for the role of VKAs, including immunoallergic phenomena and, above all, microcirculatory thrombotic processes, are hypothetical and not universally accepted.

[Polymorphic eruption of pregnancy and acquired hemophilia A]. / Éruption polymorphe de la grossesse associée à une hémophilie acquise A.

BACKGROUND: Acquired haemophilia A (AHA) is a rare and serious disease, and instances of association with skin diseases have been described. We report a case of postpartum AHA associated with atypical polymorphic eruption of pregnancy (PEP). PATIENTS AND METHODS: Following delivery of her second child, a 27-year-old woman developed a generalised pruritic erythematous papular and vesicular rash in plaques. The diagnosis of pemphigoid gestationis was ruled out on the basis of negative immunopathology results and a diagnosis of PEP was made. Lengthening of activated cephalin time was observed, without correction by addition of control plasma, and prothrombin time was normal. AHA was confirmed by the very low levels of factor VIII and the presence of antifactor VIII antibody. The patient was given intravenous activated recombinant factor VII for epistaxis and gingival bleeding, followed by an infusion of polyvalent immunoglobulins and systemic corticosteroids. Both diseases regressed within a few weeks. DISCUSSION: This case is original in terms of the atypical presentation of AHA associated with severe PEP. AHA was associated with the presence of antifactor VIII Ab. Although the disease generally occurs alone, it has already been reported during pregnancy and the postpartum period, and in association with various forms of dermatosis, including bullous pemphigoid, although to our knowledge, never in association with PEP or pemphigoid gestationis. However, neither the underlying mechanisms of this association of PEP and AHA, which was probably not a chance occurrence, nor the risks of relapse of these conditions during subsequent pregnancies have been elucidated.

Induction of neural differentiation in cultures of amphibian undetermined presumptive epidermis by cyclic AMP derivatives.

Induction of neural differentiation in cultures of undetermined presumptive epidermis from three amphibian species was achieved by the addition of 1 millimolar dibutyryl adenosine 3',5'-monophosphate, 8-bromadenosine 3',5'-monophosphate, or adenosine C',E'-monophosphate together with theophylline. Adenosine 5'-monophosphate, adenosine 2',3'-monophosphate, dibutyryl guanosine 3',5'-monophosphate, and butyrate at 1 millimolar are ineffective. These results suggest that the action of the primary inductor or inductors may be mediated via adenosine 3',5'-monophosphate.

Induction of melanized cells from a goldfish erythrophoroma: isolation of pigment translocation variants.

Melanization was induced in some cells of a goldfish tumor cell line (GEM-81) by cultivating the cells in autologous serum. The melanized cells continued to proliferate in vitro and several clones were isolated that differed with respect to cell morphology and intracellular distribution of pigment. Some of the clones consisted of cells able to translocate their melanosomes in response to epinephrine, melatonin, or adenosine 3', 5'-monophosphate.

Common origin of pigment cells.

The fundamentally diverse vertebrate pigment cells, melanophores, xanthophores, and iridophores, contain pigmentary organelles known, respectively, as melanosomes, pterinosomes, and reflecting platelets. Their pigments are mealanins pteridines, and purines. Mosaic pigment cells containing more than one type of organelle have been observed and mosaic organelles containing more than one type of pigment have been discovered. It is proposed that the various pigment cells are derived from a stem cell that contains a primordial organelle of endoplasmic reticular origin. This primordial organelle can differentiate into any of the known pigmentary organelles.

[Efficacy of rituximab in a case of refractory bullous pemphigoid]. / Efficacité du rituximab dans une pemphigoïde bulleuse en échec thérapeutique.

BACKGROUND: The mainstay in the treatment of bullous pemphigoid (BP) is corticosteroids. Immunosuppressive agents might be used for steroid-sparing effect. We report the case of a patient with refractory BP successfully treated with rituximab. PATIENTS AND METHODS: An 83-year-old woman was hospitalized in January 2005 for severe BP. She was initially treated with 30 g/day of clobetasol propionate 0.05% and methotrexate (20 mg/week), with partial remission. However, every attempt to reduce topical corticosteroids resulted in a relapse of the patient's BP. Subsequently, mycophenolate mofetil, azathioprine, dapsone, intravenous immunoglobulins, topical tacrolimus and systemic glucocorticoids (steroid-dependency at 20 mg/day) failed to induce complete remission. In December 2005, we decided to treat the patient with four infusions of rituximab 375 mg/m(2) at 1-week intervals, and this led to a dramatic reduction of the severity of BP. In May 2006, a second course of rituximab was given. One month later, for the first time in 18 months, complete clinical and immunological remission of BP was noted. The patient remains in complete remission, without treatment, 2 years after the last infusion of rituximab. DISCUSSION: The B cell-modulating effect of rituximab has encouraged its use in a variety of autoimmune diseases including pemphigus. Only five cases of refractory BP, treated with rituximab (including two paediatric cases), have so far been reported. In three of these cases, follow-up was too short to allow detection of any relapse and the other two patients had lymphocytic leukaemia requiring rituximab infusions every 2 months. In our case, the two courses of rituximab were well tolerated, induced complete clinical and immunological remission and enabled discontinuation of local and systemic corticosteroids. CONCLUSION: Rituximab could offer a safe and effective therapeutic alternative for refractory BP.

Purification and properties of a four iron-four sulfur protein from a Pseudomonas species.

We have isolated an iron-sulfur proteins from a Pseudomonas species grown on glucose. This protein has different properties from the two known iron-sulfur proteins isolated from other Pseudomonas species: rubredoxin and putidaredoxin. The iron-sulfur protein was purified to homogeneity by DEAE-cellulose column chromatography and Sephadex G-75 gel filtration. The absorption spectrum of the oxidized iron-sulfur protein shows a peak at 283 nm with shoulders at about 290, 320, and 410 nm. The protein contains 4 g atoms of iron and 4 moles of labile sulfur per mole of protein, and has a molecular weight of approximately 14,000. The amino acid composition of the protein shows a predominance of acidic amino acids. The Pseudomonas protein was found to be active for both photosynthetic nicotinamide nucleotide reduction by chloroplasts and cytochrome c reduction by spinach ferredoxin-NADP+ reductase [EC 1.6.7.1]. On the basis of these results, this protein appears to be unique among all known ferredoxins. From an evolutionary point of view, it appears to be more closely related to Azotobacter ferredoxin than to Desulfovibrio ferredoxin.

Tropic effect of dexamethasone on goldfish melanocytoma cells: induction of calcium-dependent but protein synthesis-independent morphological changes.

Treatment of melanocytoma cells of goldfish origin with dexamethasone leads to rapid morphological changes, flattening of cell body and extension of dendrites. This effect is independent of protein synthesis but requires the presence of extracellular calcium, indicating that it is a "tropic effect" distinct from the typical "trophic effects" of steroid hormones that involve de novo protein synthesis.

Nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate-linked succinic semialdehyde dehydrogenases in a Pseudonomas species.

A Pseudomonas species grown on polyamines was found to have the following enzymes that can dehydrogenate succinic semialdehyde: a constitutive nicotinamide adenine dinucleotide phosphate (NADP)-linked dehydrogenase, an inducible NAD-linked dehydrogenase specific for succinic semialdehyde (EC 1.2.lb), and more than one inducible NAD-linked aminoaldehyde dehydrogenase which can act on succinic semialdehyde, 3-aminopropanal, and 4-aminobutanal. These enzymes have been separated from each other by ammonium sulfate precipitation, column chromatography on diethylaminoethyl-Sephadex, and electrophoresis on polyacrylamide gel. The level of NAD-linked succinic semialdehyde dehydrogenase in cells grown on various C and N sources has been determined and found to be as expected of an inducible enzyme with, however, two slight variations: the basal level of the enzyme in cells grown on Casamino Acids is relatively high and readily detectable, and the level of this enzyme is the same when the cells are grown on gamma-aminobutyrate with or without glucose and is, therefore, not subject to the classical glucose effect.

The activation of adrenal cortex mitochondrial malic enzyme by Ca2+ and Mg2+.

Adrenal cortex mitochondria prepared by a standard method do not exhibit malic enzyme activity. Addition of physiological concentrations of Ca2+ and Mg2+ enables these mitochondria to reduce added NADP+ by malate to form free NADPH. Half-maximum activation of the mitochondrial malic enzyme requires 0.3 mM Ca2+ and 1 mM Mg2+. Solubilized mitochondrial malic enzymes is independent of Ca2+ and has a K M of 0.2 mM for Mg2+. The Ca2+ effect is dependent on an initial period of active Ca2+ uptake which also causes other changes in respiratory properties similar to those observed with mitochondria from other tissues. After Ca2+ accumulation has taken place, free Ca2+, but not additional accumulation, is still required for malic enzyme activity. The requirement for Mg2+ can be met by Mn2+ (1 mM). This concentration of Mn2+ alone yielded only a slight activation of mitochondrial malic enzyme while higher concentrations of Mn2+ alone gave good activation of the mitochondrial malic enzy.e The NADPH generated by the Ca2+-Mg2+ activated malic enzyme effectively supports the 11beta-hydroxylation of deoxycorticosterone, whereas in the presence of malate, or malate plus Mg2+ but absence of Ca2+, the energy linked transhydrogenase supplies all the required NADPH. The activated malic enzyme appears to be more efficient than transhydrogenase in generating NADPH to support 11beta-hydroxylation. Cyanide and azide have been found to inhibit solubilized mitochondrial malic enzyme.

Turnover of putrescine in a Pseudomonas species.

A Pseudomonas species was found to readily take up labeled putrescine added in trace amounts to any of four growth media, bis-(3-aminopropyl)-amine, 4-aminobutyrate, glucose-NH(3), and Casamino Acids, although the rate of uptake varied considerably from one medium to another. Putrescine degradation, as well as excretion and conversion to hydroxyputrescine, was demonstrated in all four media, indicating that this organism has a constitutive putrescine degradation pathway. The extents of putrescine degradation, excretion, and conversion to hydroxyputrescine are shown for these four growth media through an incubation period of 1 hr. These results document more fully the experimental details behind a previous communication which postulated that the constitutive degradation of putrescine participates in the regulation of intracellular putrescine concentration. The significance of this apparent violation of the general concept that synthetic end products are normally not degraded is discussed.

An association of actin isoforms with the expression of motile response in pigmentation variants induced from goldfish erythrophoroma cells.

Comparison of actin isoforms in unpigmented goldfish cells (a normal dermal fibroblast-like cell line, and an unpigmented erythrophoroma cell line capable of being induced to undergo melanization) and in normal and neoplastic melanized goldfish cells shows that the melanized phenotype is accompanied by the presence of multiple actin isoforms. In contrast, the unpigmented cells have only beta-actin. The possible significance of this to pigment organelle translocation is discussed.

Immunofluorescence evidence for cytoskeletal rearrangement accompanying pigment redistribution in goldfish xanthophores.

Immunofluorescence and phase-contrast microscopic studies of goldfish xanthophores with aggregated or dispersed pigment show two unusual features. First, immunofluorescence studies with anti-actin show punctate structures instead of filaments. These punctate structures are unique for the xanthophores and are absent from both goldfish dermal non-pigment cells and a dedifferentiated cell line (GEM-81) derived from a goldfish xanthophore tumor. Comparison of immunofluorescence and phase-contrast microscopic images with electron microscopic images of thin sections and of Triton-insoluble cytoskeletons show that these punctate structures represent pterinosomes with radiating F-actin. The high local concentration of actin around the pterinosomes results in strong localized fluorescence such that, when the images have proper brightness for these structures, individual actin filaments elsewhere in the cell are too weak in their fluorescence to be visible in the micrographs. Second, whereas immunofluorescence images with anti-tubulin show typical patterns in xanthophores with either aggregated or dispersed pigment, namely, filaments radiating out from the microtubule organizing center, immunofluorescence images with anti-actin or with anti-intermediate filament proteins show different patterns in xanthophores with aggregated versus dispersed pigment. In cells with dispersed pigment, the punctate structures seen with anti-actin are relatively evenly distributed in the cytoplasm, and intermediate filaments appear usually as a dense perinuclear band and long filaments elsewhere in the cytoplasm. In cells with aggregated pigment, both intermediate filaments and pterinosomes with associated actin are largely excluded from the space occupied by the pigment aggregate, and the band of intermediate filaments surrounds not only the nucleus but also the pigment aggregate. The patterns of distribution of the different cytoskeleton components, together with previous results from this laboratory, indicate that formation of the pigment aggregate depends at least in part on the interaction between pigment organelles and microtubules. The possibility that intermediate filaments may play a role in the formation/stabilization of the pigment aggregate is discussed.

Epinephrine-induced pigment aggregation in goldfish melanophoroma cells: apparent involvement of an unknown second messenger.

Using a goldfish-derived melanized cell line, we attempted to determine the identity of the signal transduction system/second messenger for epinephrine-induced aggregation of melanosomes in a goldfish cell line. The results show that the second messenger is unknown. It is not 1) influx of extracellular calcium, 2) release of intracellular stored calcium via the phosphoinositide pathway, 3) cGMP, or 4) decrease of cAMP. These results suggest that there is an unknown second messenger for this activity of epinephrine.

Purification of anterogin, a protein factor necessary for the dispersion of carotenoid droplets in permeabilized xanthophores of goldfish.

We reported previously that the dispersion of carotenoid droplets in permeabilized xanthophores requires cAMP, ATP, and a cytosolic factor present in several secretory tissues as well as in xanthophores. We have now purified this factor from beef liver to apparent/near homogeneity. It appears to be a heterodimer with Mr approximately 125,000. The purified factor has little or no ATPase activity, with or without the presence of actin. Nor does it stimulate the ATPase activity of carotenoid droplets. Its exact function in carotenoid droplet dispersion is thus unclear. Since dispersion of carotenoid droplets is an anterograde translocation, we propose the name anterogin for this protein. We also report that yeast cytosol has anterogin activity.

Actin-dependent carotenoid droplet dispersion in permeabilized cultured goldfish xanthophores.

Organelle translocations are essential cellular processes. Although much progress has been made with regards to microtubule-dependent organelle translocations, little is known about actin-dependent organelle translocation(s) except cytoplasmic streaming in Nitella. On the other hand, there is indirect evidence that actin-dependent organelle translocation may be involved in secretion. We now present evidence that the dispersion of the pigment organelles carotenoid droplets in goldfish xanthophores is apparently actin dependent and that this process may be related to secretory processes. We show that, in digitonin-permeabilized goldfish xanthophores, the pigment organelles can be induced to disperse by a combination of cAMP, ATP, and xanthophore cytosol. This induced dispersion is inhibited by DNase I, phalloidin, or anti-actin, but not by anti-tubulin or anti-intermediate filament proteins, suggesting a dependence on F-actin. Since the dispersion of carotenoid droplets and secretion both involve outward translocation of organelles, we tested the possibility that cytosols of secretory tissues have similar activity. Such activity was indeed found in different tissues, apparently in parallel with the secretory activity of the tissues, suggesting that pigment dispersion in xanthophores and some secretory processes may share a common component.

Unusual responses of cultured Fundulus heteroclitus melanophores to epinephrine and ions, paradox of K+ versus Na+.

Fundulus heteroclitus melanophores were successfully cultured and maintained in culture for up to 2 months. Compared to other teleost melanophores in the fin, scale, or split fin preparation, the cultured melanophores show unusual responses to both epinephrine and ion solutions. First, they aggregated their melanosomes in response to concentrations of epinephrine as low as 10(-12) M. Second, the melanophores in a 6-day, or older, culture aggregated their melanosomes in response to both sodium and potassium ion solutions. This is in contrast to 4-day-old cultures (and reports of noncultured melanophores) where melanosomes are aggregated in response to potassium but dispersed in sodium ion solutions.