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Volker Schuster

Publications and source records attributed to Volker Schuster.

11 recordsLinked to original sources
PubMed2003

Ligneous conjunctivitis, hydrocephalus, hydrocele, and pulmonary involvement in a child with homozygous type I plasminogen deficiency.

UNLABELLED: Ligneous conjunctivitis is a rare and unusual form of chronic pseudomembranous conjunctivitis which usually starts in early infancy. Plasminogen deficiency has recently been associated with ligneous conjunctivitis. The disease may be associated with pseudomembranous lesions of other mucous membranes in the mouth, nasopharynx, trachea, and female genital tract and also with congenital hydrocephalus. In this report, a 1-month-old Turkish boy who had pseudomembranous conjunctivitis, occlusive hydrocephalus, and hydrocele is presented. After surgery for ventriculo-peritoneal shunt establishment, he developed inspiratory stridor, respiratory distress, and pulmonary atelectasis. Tracheal pseudomembranes were also demonstrated by bronchoscopy. Plasminogen antigen level and plasminogen activity were very low. Genomic DNA from the patient was screened for mutations in the plasminogen gene and a homozygous L650fsX652 mutation (deletion of 2081C) was detected. Both of his parents were heterozygous for this mutation. He died due to respiratory failure during follow-up. CONCLUSION: Ligneous conjunctivitis related to type I plasminogen deficiency is relatively common in the Turkish population, however, mutations are heterogeneous and a common founder is unlikely.

Chromosome Deletion↗
PubMed2003

Mutation spectrum of human SLC39A4 in a panel of patients with acrodermatitis enteropathica.

Acrodermatitis enteropathica is rare autosomal recessive disorder characterized by a severe nutritional zinc deficiency. We and others have recently identified the human gene encoding an intestinal zinc transporter of the ZIP family, SLC39A4, as the mutated gene in acrodermatitis enteropathica (AE). A first mutation screening in 8 AE families (15 patients out of 36 individuals) revealed the presence of six different mutations described elsewhere. Based on these results, we have evaluated the involvement of SLC39A4 in 14 patients of 12 additional AE pedigees coming either from France, Tunisia, Austria or Lithuania. A total of 7 SLC39A4 mutations were identified (1 deletion, 2 nonsense, 2 missense, and 2 modifications of splice site), of which 4 are novel: a homozygous nonsense mutation in 3 consanguineous Tunisian families [c.143T>G (p.Leu48X)], a heterozygous nonsense mutation (c.1203G>A (p.Trp401X)) in a compound heterozygote from Austria also exhibiting an already known missense mutation, and distinct homozygous mutations in families from France or Tunisia [c.475-2A>G and c.184T>C (p.Cys62Arg)]. Furthermore, two other potential mutations [c.850G>A (p.Glu284Lys) and c.193-113T>C] were also observed at homozygous state in a French family formerly described. This study brings to 21 the number of reported SLC39A4 mutations in AE families.

Acrodermatitis↗
PubMed2003

A K19E missense mutation in the plasminogen gene is a common cause of familial hypoplasminogenaemia.

The prevalence of familial plasminogen deficiency in Scotland has recently been calculated at 2.9/1000. However, little is known of the molecular genetic background and the frequency of plasminogen gene mutations in most cases of inherited plasminogen deficiency. Having previously identified 28 unrelated subjects with familial plasminogen deficiency from a cohort of 9611 blood donors, we have now reviewed 19 of these 28 subjects and screened the plasminogen gene in 15 subjects with hypoplasminogenaemia (plus five relatives) and four subjects with dysplasminogenaemia for mutations and polymorphisms. A missense mutation K19E in the plasminogen gene was found in 13 of the 15 propositi with hypoplasminogenaemia, in one of these in a homozygous manner. In two subjects with hypoplasminogenaemia, two new mutations (P353A and R471X) were identified. These three different mutations, if inherited in a homozygous or compound-heterozygous manner, may be associated with the development of ligneous conjunctivitis. In four subjects with dysplasminogenaemia, three heterozygous mutations (C548G, n = 1; A601T, n = 1; G693R, n = 2) were found. None of the propositi with plasminogen deficiency developed venous thrombosis at any time. In conclusion, the K19E mutation in the plasminogen gene is a common cause of hypoplasminogenaemia in Scotland, with an estimated prevalence of around 0.14%.

Amino Acid Sequence↗
PubMed2002

Unimpaired activation of c-Jun NH2-terminal kinase (JNK) 1 upon CD40 stimulation in B cells of patients with X-linked agammaglobulinemia.

X-linked agammaglobulinemia (XLA) is caused by mutations in the gene encoding the cytoplasmic Bruton's tyrosine kinase (Btk). Btk has been shown to play an essential role in the development of B1 (CD5+) and conventional circulating mature B cells (B2) in mouse and man. It has been shown in earlier studies that Btk is involved in both the BCR- and CD40-mediated signaling pathways. In this study, we analyzed the responsiveness of Epstein-Barr virus (EBV) transformed B cells from nine XLA patients to CD40 stimulation, particularly the CD40 induced activation of c-Jun N-terminal kinase (JNK). In eight XLA patients the JNK activation was unimpaired and in one case INK could not be activated by anti-CD40 stimulation. Btk protein expression was detectable by Western blotting in six cases, in one case Btk expression was drastically reduced, and in three cases no Btk expression could be observed. Btk kinase activity was found in three cases and it was reduced in one and not detectable in five cases. Furthermore, in one female patient with an agammaglobulinemia, Btk expression and function as well as JNK activation by CD40 stimulation was unimpaired. Our findings demonstrate that INK activation via the CD40 signaling pathway is intact in EBV-transformed B cells of most if not all XLA patients, independent of the mutation and its effect on Btk expression and kinase activity. We suggest that Btk is not necessary for the activation of INK upon CD40 stimulation, at least in the B cell subpopulation we had studied. We cannot exclude that these B cells belong to a "leaky" B-cell subpopulation in which the CD40 signaling pathway has become independent of Btk function.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed2002

Bruton's tyrosine kinase is activated upon CD40 stimulation in human B lymphocytes.

Bruton's tyrosine kinase (Btk) is known to be involved in a broad array of signal transduction pathways necessary for the proliferation, survival and development of B cells. Mutations in the Btk gene are causually linked to the development of X-linked agammaglobulinemia (XLA) in humans. We show here, that CD40 ligation leads to tyrosine phosphorylation of Btk in the human immature B cell line MHH-PREB-1. Even though the CD40-mediated tyrosine phosphorylation of Btk is less efficient than that mediated through the B cell receptor, CD40 stimulation results in a marked and continous activation of Btk in MHH-PREB-1 cells and, to a lesser extent, in a transient Btk activation in Daudi cells. Furthermore, in Daudi cells we observed that tyrosine phosphorylation and activation of Btk is correlated with its translocation from the cytosolic to the membraneous fraction. These data suggest that, in addition to the BCR, CD40 is a surface receptor through which the activity of Btk can be stimulated in human B cells.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed2002

A season of aseptic meningitis in Germany: epidemiologic, clinical and diagnostic aspects.

OBJECTIVE: We assessed epidemiologic, clinical and laboratory features of aseptic meningitis during one season of multiserotype enteroviral meningitis in East Germany in 70 consecutive patients with aseptic meningitis admitted to the Children's University Hospital Leipzig. RESULTS: Patients, age 1 to 16 years, typically presented with headache, emesis and fever, whereas signs of meningeal irritation were only moderately expressed in one-half of the patients. The median number of leukocytes in the CSF was 151 cells/mm(3) (range, 2 to 1,820) with a high percentage of polymorphonuclear cells (PMNs). Initial blood counts showed mild leukocytosis and pronounced PMN predominance (78.9 +/- 1.3%). The percentage of PMNs in the peripheral blood decreased in favor of mononuclear cells after 3 days to a pattern more compatible with viral infection as opposed to that suggestive for bacteria in the beginning. Mean cerebrospinal fluid values of protein, glucose and lactate and the C-reactive protein were mildly elevated or normal. Nonpolio enteroviruses were detected in 30 of 70 patients. Subsequent serotyping revealed echovirus type 13 (13 patients), type 6 (2), type 30 (1) and coxsackie B virus type 5 (2). There were no differences in demographic or clinical data between enterovirus positive and negative patients. CONCLUSIONS: Even though individual laboratory values do not solely allow discrimination between viral and bacterial meningitis, the combined epidemiologic, clinical and laboratory data facilitate the diagnosis of aseptic meningitis in most cases. Viral diagnostics, identifying echovirus type 13 that thus far has not been associated with epidemics of meningitis, adds important epidemiologic information.

Adolescent↗
PubMedDate not supplied

Ligneous conjunctivitis.

Ligneous conjunctivitis (McKusick 217090) is a rare form of chronic conjunctivitis characterized by the development of firm fibrin-rich, woody-like pseudomembraneous lesions mainly on the tarsal conjunctivae. Less frequently, similar lesions may occur on other mucous membranes of the body indicating that these manifestations are part of a systemic disease. Histopathological findings from affected humans and (plasminogen-deficient) mice indicate that wound healing, mainly of injured mucosal tissue, is impaired due to markedly decreased (plasmin-mediated) extracellular fibrinolysis. Pseudomembraneous lesions of the eyes and other mucosal tissue mainly contain clotted fibrin(ogen). Actually, systemic plasminogen deficiency has been linked to ligneous conjunctivitis in humans and mice. In one case, ligneous conjunctivitis has been induced by antifibrinolytic treatment with tranexamic acid. Further rare associated disorders of ligneous conjunctivitis are congenital occlusive hydrocephalus and juvenile colloid milium. This review outlines the historical background, clinical characteristics of ligneous conjunctivitis and its associated complications, histological abnormalities of pseudomembraneous lesions, inheritance, hemostasiologic and molecular genetic findings in affected patients, current treatment approaches, and the plasminogen-deficient mouse as an animal model.

Animals↗