Severe type I plasminogen (PLG) deficiency has been causally linked to a rare chronic inflammatory disease of the mucous membranes that may be life threatening. Here we report clinical manifestations, PLG plasma levels, and molecular genetic status of the PLG gene of 50 patients. The most common clinical manifestations among these patients were ligneous conjunctivitis (80%) and ligneous gingivitis (34%), followed by less common manifestations such as ligneous vaginitis (8%), and involvement of the respiratory tract (16%), the ears (14%), or the gastrointestinal tract (2%). Four patients showed congenital occlusive hydrocephalus, 2 with Dandy-Walker malformation of cerebellum. Venous thrombosis was not observed. In all patients, plasma PLG levels were markedly reduced. In 38 patients, distinct mutations in the PLG gene were identified. The most common genetic alteration was a K19E mutation found in 34% of patients. Transient in vitro expression of PLG mutants R134K, delK212, R216H, P285T, P285A, T319_N320insN, and R776H in transfected COS-7 cells revealed significantly impaired secretion and increased degradation of PLG. These results demonstrate impaired secretion of mutant PLG proteins as a common molecular pathomechanism in type I PLG deficiency. IntroductionPlasminogen (PLG) plays an important role in intra-and extravascular fibrinolysis, wound healing, cell migration, angiogenesis, and embryogenesis. 1 Plg is primarily synthesized by liver tissue. 2 However, other minor sources identified in mice include adrenal gland, kidney, brain, testis, heart, lung, uterus, spleen, thymus, and gut tissue. 3 In humans, the cornea has been described as an extrahepatic site of PLG synthesis. 4 Inherited PLG deficiency in humans can be divided into 2 types: true PLG deficiency (type I, or hypoplasminogenemia) and dysplasminogenemia (type II). In the former, both immunoreactive PLG level and functional activity are reduced, while the latter shows a normal or slightly reduced level of immunoreactive PLG while functional activity is significantly decreased. It has been shown by several authors since 1995 that homozygous or compound-heterozygous type I PLG deficiency is a major cause of a rare inflammatory disease affecting mainly mucous membranes in different body sites. 5,6 The most common clinical manifestation is ligneous conjunctivitis, characterized by development of fibrin-rich, woodlike ("ligneous") pseudomembranous lesions. Involvement of the cornea may result in blindness. Other, less common manifestations are ligneous gingivitis, otitis media, ligneous bronchitis and pneumonia, involvement of the gastrointestinal or female genital tract, juvenile colloid milium of the skin, and congenital occlusive hydrocephalus. 6 In severely affected patients, prognosis is poor and treatment options are few. Worldwide, more than 150 patients with this disease have been reported since 1847, the date of first description. 6,7 From the Hospital for Children and Adolescents, University of Leipzig, Leipzig, Germany; For personal use o...

Summary.  Plasminogen deficiency has emerged as a well‐recognized disorder in which reduced levels of plasminogen lead to the development of pseudo membranes on mucosal surfaces, with subsequent end‐organ damage of the affected tissue. Ligneous conjunctivitis is the most recognizable, well‐documented, and common presentation of the clinical syndromes associated with plasminogen deficiency, although numerous other organs have been reported to be affected. Interestingly, while plasminogen deficiency was initially believed to be related to development of venous thromboembolic disease, more recent data suggest that decreased plasminogen levels may not, in and of themselves, increase the risk of thrombosis. Two types of plasminogen deficiency have been described in the literature. Type I represents a quantitative deficiency and type II a qualitative deficiency. It appears that hypoplasminogenaemia (type I deficiency) is the type most associated with pseudomembrane disease. A variety of genetic mutations has been identified recently and is reported to lead to these disorders. These defects have been identified in diverse populations, with no specific ethnic predilection. However, this disorder may have increased prevalence in areas and communities where consanguinity is more common. Despite the fact that the characteristic lesions are now better recognized and plasminogen levels are accurately and easily measured, adequate treatment of the clinical manifestations of this disorder is lacking. For ligneous conjunctivitis, a plasminogen concentrate formulated into an ophthalmologic preparation has been found to be an effective local therapy. Unfortunately, no plasminogen concentrate is currently available commercially for either systemic or local therapy.

Summary.  Plasminogen activator inhibitor type 1 (PAI‐1) is an important component of the coagulation system that down‐regulates fibrinolysis in the circulation. Reduced PAI‐1 levels may result in increased fibrinolysis and an associated bleeding diathesis. Clear documentation of PAI‐1 deficiency as a cause of a bleeding disorder has been rare. PAI‐1 was initially identified in the 1980s, and the first reported case of PAI‐1 deficiency appeared in 1989. Several reports followed, although only two identified an underlying genetic defect. These reports of PAI‐1 deficiency suggest that affected individuals exhibit mild to moderate bleeding symptoms, including epistaxis, menorrhagia, and delayed bleeding after trauma or surgical procedures. Affected individuals rarely exhibit spontaneous bleeding events commonly seen in other procoagulant deficiencies. The majority of bleeding events are controlled with antifibrinolytic agents, such as tranexamic acid and ε‐aminocaproic acid. A major issue that contributes to difficulty in establishing an accurate diagnosis of PAI‐1 deficiency is that the activity assay is accurate in detection of elevated levels but not at the lowest range. Reported normal ranges begin at zero, thereby making a deficiency state because of a dysproteinaemia difficult to distinguish from that of a normal unaffected individual. Although the antigen assay may be helpful in some circumstances, it assists only with complete quantitative disorders. Because of lack of standardized commercially available PAI‐1 activity assay sensitive in the lowest range, the true prevalence of this rare condition has not been established.

Recent work has indicated that sigma receptor ligands can modulate potassium channels. However, the only sigma receptor characterized at the molecular level has a novel structure unlike any other receptor known to modulate ion channels. This 26-kDa protein has a hydropathy profile suggestive of a single membranespanning domain, with no apparent regions capable of G-protein activation or protein phosphorylation. In the present study patch clamp techniques and photoaffinity labeling were used in DMS-114 cells (a tumor cell line known to express sigma receptors) to investigate the role of the 26-kDa protein in ion channel modulation and probe the mechanism of signal transduction. The sigma receptor ligands N-allylnormetazocine (SKF10047), ditolylguanidine, and (؎)-2-(N-phenylethyl-N-propyl)-amino-5-hydroxytetralin all inhibited voltage-activated potassium current (I K ). Iodoazidococaine (IAC), a high affinity sigma receptor photoprobe, produced a similar inhibition in I K , and when cell homogenates were illuminated in the presence of IAC, a protein with a molecular mass of 26 kDa was covalently labeled. Photolabeling of this protein by IAC was inhibited by SKF10047 with half-maximal effect at 7 M. SKF10047 also inhibited I K with a similar EC 50 (14 M). Thus, physiological responses to sigma receptor ligands are mediated by a protein with the same molecular weight as the cloned sigma receptor. This indicates that ion channel modulation is indeed mediated by this novel protein. Physiological responses were the same when cells were perfused internally with either guanosine 5 -O-(2-thiodiphosphate) or GTP, indicating that signal transduction is independent of G-proteins. These results demonstrate that ion channels can be modulated by a receptor that does not have seven membrane-spanning domains and does not employ G-proteins. Sigma receptors thus modulate ion channels by a novel transduction mechanism.Sigma receptors are widely distributed in neuronal and nonneuronal tissue and are distinguished by their ability to bind a broad range of chemically unrelated ligands, including (ϩ)-opiates, neuroleptic drugs, ditolylguanidine (DTG), 1 and phencyclidine-related compounds (1-3). Although the biological activity of ligands suggests that sigma receptors may be involved in behavioral, psychological, and motor functions (1-3), the cellular actions of sigma receptors are poorly understood. Recent studies in melanotrophs (4) and the neurohypophysis (5) showed that sigma receptor ligands inhibit voltage-activated potassium current (I K ), but the signal transduction pathways associated with sigma receptor activation remain unknown.Molecular characterization of sigma receptors has raised intriguing questions about how these receptors generate cellular responses. The high affinity sigma receptor photoprobe iodoazidococaine (IAC) has labeled a 26-kDa protein in rat liver, rat brain, and human placenta (6). Cloning studies have confirmed that both human and rodent sigma receptor cDNAs encode a 25.3-kDa protein (7-10). The protein ...

Despite significant advances in the treatment of haemophilia, including availability of recombinant coagulation factor replacement products and the use of prophylactic infusion regimens, the segment of haemophilic patients who develop inhibitory antibodies remain at higher risk for morbidity and mortality associated with recurrent or uncontrolled bleeding events. Bypassing agents represent the mainstay of treatment and prevention of bleeding. The most commonly used of the currently available therapeutic agents are a plasma-based therapy, factor eight inhibitor bypassing activity, vapour heated, and a recombinant therapy, NovoSeven (recombinant activated factor VIIa). A substantial body of literature exists to document efficacy and adverse event profiles for these two products. There is, however, a paucity of data arising from adequately powered prospective trials to determine optimal treatment and dosing in various clinical situations. Certain clinical circumstances, patient profiles, individual responses, or provider predilection may lead to preferential use of one of these products over the other; however, the continued presence of both agents in the therapeutic armamentarium remains critically important to this fragile population. The historical use, clinical practice concerns, published comparative studies and methods for optimization of these two bypassing agents are reviewed.