Abnormalities of erythrocyte glycoconjugates are identical in two families with congenital dyserythropoietic anemia type II with different chromosomal localizations of the disease gene.

We analyzed erythrocyte glycoconjugates in two families with congenital dyserythropoietic anemia type II (CDA-II): family 2 with the typical localization of the disease gene to chromosome 20q11.2 and family 1 in which this localization was excluded. Despite the different genetics, the erythrocyte glycoconjugate abnormalities in the two families were identical suggesting a complex inheritance of CDA-II. We also found that erythrocyte anion exchanger 1 protein is decreased in CDA-II homozygotes and obligate carriers alike.

Molecular analysis of three novel G6PD variants: G6PD Pedoplis-Ckaro, G6PD Piotrkow and G6PD Krakow.

We present three novel mutations in the G6PD gene and discuss the changes they cause in the 3-dimensional structure of the enzyme: 573C-->G substitution that predicts Phe to Leu at position 191 in the C-terminus of helix alphae, 851T-->C mutation which results in the substitution 284Val--> -->Ala in the beta+alpha domain close to the C-terminal part of helix alphaj, and 1175T-->C substitution that predicts Ile to Thr change at position 392.

Expression of platelet surface receptors and early changes in platelet function in patients with STEMI treated with abciximab and clopidogrel versus clopidogrel alone.

BACKGROUND: Platelets play a crucial role in the pathogenesis of acute coronary syndromes (ACS). The efficacy of antiplatelet treatment is pivotal in the success of percutaneous coronary intervention (PCI) performed in patients with ACS. OBJECTIVE: The aim of the study was to investigate the effects of clopidogrel with or without abciximab on the expression of platelet surface receptors and platelet function in patients with ST-segment elevation myocardial infarction (STEMI) undergoing PCI. MATERIALS AND METHODS: Thirty patients with STEMI were included in the study. During acute primary coronary intervention, patients received aspirin (acetylsalicylic acid) and clopidogrel in a loading dose of 300mg. Clopidogrel was the only antiplatelet therapy used by nine patients (group B). Twenty-one patients (group A) received additional abciximab. Blood samples were collected and analyzed twice: before and up to 22 hours after administration of antiplatelet therapy. The platelet aggregation was established as primary platelet-related hemostasis (closure time [CT] assessed using the PFA100 system). The absolute number of platelet surface antigens as CD41a, CD42a, CD42b, CD61, and CD62P were determined by flow cytometry analysis. RESULTS: The study revealed a statistically significant increase in CT induced by adenosine diphosphate and adrenaline (epinephrine) +130 seconds (p < 0.0001) and +94 seconds (p < 0.0001), respectively, in group A patients post-therapy. While in group B the parameters of CT did not change after treatment. In addition, the absolute number of CD41a antigens (glycoprotein [GP] IIb/IIIa) increased significantly after treatment in group A. No significant changes were observed after treatment in the expression of CD62P (P-selectin) antigens in either treatment group. There was a significant reduction in the percentage of CD62P-positive platelets in group B after antiplatelet therapy. CONCLUSIONS: The absolute number of GP IIb/IIIa receptors increases and platelets are not activated up to 12 hours after cessation of abciximab therapy. Treatment of STEMI patients undergoing PCI with a loading dose of clopidogrel reduces the percentage of active platelets but does not influence the CT.

[Beta-Thalassemia in Poland. I. Mediterranean mutations in beta-thalassemia]. / Beta-talasemia w Polsce. I. Mutacje sródziemnomorskie.

UNLABELLED: The aim of the present investigation was to verify a common view that thalassemia in Poland is a very rare disease. MATERIAL AND METHODS: 600 patients (270 male and 330 female) aged 2-85 years with microcytosis and no evidence of iron deficiency were examined for beta-thalassemia. Hemoglobin A2 and hemoglobin F and bilirubin were evaluated. Patients with elevated A2 hemoglobin concentration were examined for 8 common Mediterranean mutations. RESULTS: Hemoglobin A2 was increased in 106 patients. In 48 patients there was also an elevation of hemoglobin F and in 42 - of serum bilirubin. 7 different mutations were detected in 46 heterozygous patients (numbers of patients with a particular mutation are in square brackPis): IVS1-6(T>C) [15], IVS2-745(C>G) [14], IVS2-1(G>A) [10], IVS1-1(G>A) [2], CD6-A [2], CD39(C>T) [2], IVS1-110(G>A) [1]. CONCLUSIONS: Frequencies of individual mutations in Poland were different from those encountered in Mediterranean and some Central European countries. Our data indicate that fl-thalassemia in Poland is not a rare disease and should be considered in differential diagnosis of hypochromic anemia.

[Thalassemia beta in children from Pomerania Region]. / Thalassemia beta u dzieci z Województwa Pomorskiego.

The thalassemias are inherited disorders resulting from deficient synthesis of one or more polypeptide chains of normal haemoglobin. There are two main groups of thalassemia: alpha and more common beta. The carriage of thalassemia genes are widely spread and the disease is considered the most common genetic disorder worldwide. Thalassemias are particularly prevalent in inhabitants of Italy, Greece, Spain, Mediterranean Islands, West Africa and some parts of Asia. The most common thalassemia beta cases are characterized from asymptomatic to severe microcytic anaemia with hepatosplenomegaly and physical development disturbances. The authors present eight unrelated children from the Pomerania Region of Poland complaining of chronic microcytic anaemia with normal iron level. Elevated level of haemoglobin A2 and in some of them haemoglobin F revealed thalassemia beta.

[Local complications during nasal continuous positive airway pressure method therapy]. / Powiklania miejscowe podczas terapii metoda nosowego ciaglego dodatniego cisnienia w drogach oddechowych.

A review of the current knowledge about local complications during nasal continuous positive airway pressure method therapy in the neonate with respiratory failure is the subject of this article. In the authors' conviction, local damages make up one of the main causes of failure of therapy, or its interruption, especially in the newborn with extremely low birth weight. Apart from review of the literature, the authors describe the causes of the most frequent damages as well as methods of their prevention and treatment, developed during many years of using of this form of ventilation.

Dissecting the role of dolichol in cell wall assembly in the yeast mutants impaired in early glycosylation reactions.

Evidence is presented that temperature-sensitive Saccharomyces cerevisiae mutants, impaired in dolichol kinase (Sec59p) or dolichyl phosphate mannose synthase (Dpm1p) activity have an aberrant cell wall composition and ultrastructure. The mutants were oversensitive to Calcofluor white, an agent interacting with the cell wall chitin. In accordance with this, chemical analysis of the cell wall alkali-insoluble fraction indicated an increased amount of chitin and changes in the quantity of beta1,6- and beta1,3-glucan in sec59-1 and dpm1-6 mutants. In order to unravel the link between the formation of dolichyl phosphate and dolichyl phosphate mannose and the cell wall assembly, we screened a yeast genomic library for a multicopy suppressors of the thermosensitive phenotype. The RER2 and SRT1 genes, encoding cis-prenyltransferases, were isolated. In addition, the ROT1 gene, encoding protein involved in beta1,6-glucan synthesis (Machi et al., 2004) and protein folding (Takeuchi et al., 2006) acted as a multicopy suppressor of the temperature-sensitive phenotype of the sec59-1 mutant. The cell wall of the mutants and of mutants bearing the multicopy suppressors was analysed for carbohydrate and mannoprotein content. We also examined the glycosylation status of the plasma membrane protein Gas1p, a beta1,3-glucan elongase, and the degree of phosphorylation of the Mpk1/Slt2 protein, involved in the cell wall integrity pathway.

Glycoprotein hypersecretion alters the cell wall in Trichoderma reesei strains expressing the Saccharomyces cerevisiae dolichylphosphate mannose synthase gene.

Expression of the Saccharomyces cerevisiae DPM1 gene (coding for dolichylphosphate mannose synthase) in Trichoderma reesei (Hypocrea jecorina) increases the intensity of protein glycosylation and secretion and causes ultrastructural changes in the fungal cell wall. In the present work, we undertook further biochemical and morphological characterization of the DPM1-expressing T. reesei strains. We established that the carbohydrate composition of the fungal cell wall was altered with an increased amount of N-acetylglucosamine, suggesting an increase in chitin content. Calcofluor white staining followed by fluorescence microscopy indicated changes in chitin distribution. Moreover, we also observed a decreased concentration of mannose and alkali-soluble beta-(1,6) glucan. A comparison of protein secretion from protoplasts with that from mycelia showed that the cell wall created a barrier for secretion in the DPM1 transformants. We also discuss the relationships between the observed changes in the cell wall, increased protein glycosylation, and the greater secretory capacity of T. reesei strains expressing the yeast DPM1 gene.

Heterozygosity of CDAN II (HEMPAS) gene may be detected by the analysis of erythrocyte membrane glycoconjugates from healthy carriers.

BACKGROUND AND OBJECTIVES: Congenital dyserythropoietic anemia (CDA) type I, II, and III, is associated with abnormalities of erythrocyte membrane glycoconjugates that are most pronounced in type II CDA or hereditary erythroblastic multinuclearity with a positive acidified-serum test (HEMPAS). The abnormalities consist in hypoglycosylation of polylactoaminoglycans linked to proteins (as in band 3 glycoprotein) and ceramides (known under the name of polyglycosylceramides) as well as in accumulation of some oligoglycosylceramides: lactotriaosylceramide, neolactotetraosylceramide, and sometimes globotetraosylceramide. Glycophorin A is partially unglycosylated with respect to O-linked glycans. Types I and II of the disease are inherited in an autosomal recessive fashion. The aim of the present study was to investigate a possibility that heterozygosity with respect to CDAN2 gene in healthy carriers could be detected by analysis of erythrocyte membrane glycoconjugates. DESIGN AND METHODS: We examined a family which consisted of heterozygous parents and their two sons, one of whom was afflicted with CDA II (proband) while the other was healthy. In all family members the glycosylation status of band 3 glycoprotein, polyglycosylceramides and glycophorin A was evaluated from their carbohydrate molar composition. In addition we determined erythrocyte membrane contents of oligo- and polyglycosylceramides, and agglutinability of erythrocytes by anti-i antibody. RESULTS: We found that the heterozygous parents showed, but about 50% less pronounced, most of the typical abnormalities of erythrocyte membrane glycoconjugates that were present in the proband. These abnormalities included: hypoglycosylation of band 3, accumulation and hypoglycosylation of polyglycosylceramides, and accumulation of lactotriaosylceramide. The level of neolactotetraosylceramide in the erythrocyte membranes of the parents was, however, normal. Globotetraosylceramide content was elevated in erythrocytes from the proband and, surprisingly, even more so in the parents. Glycophorin A in the proband was only slightly abnormal. Erythrocytes from both the parents and the proband expressed increased agglutinability with anti-i antibody. All glycoconjugates examined were normal in erythrocytes from the healthy son. INTERPRETATION AND CONCLUSIONS: Individuals heterozygous with respect to CDAN2 gene can be identified through determination of the carbohydrate molar composition of band 3 and polyglycosylceramides as well as by an elevated erythrocyte content of polyglycosylceramides. In the parents these abnormalities show dosage effects. Determination of the carbohydrate molar composition of glycophorin A and of oligoglycosylceramides seems to be less promising. These findings indicate that the analysis of erythrocyte membrane glycoconjugates may be a valuable addition to the repertoire of methods used in studies on the genetics of CDA.

Quantitative analysis of LacCer/CDw17 in human myelogenous leukaemic cells.

LacCer/CDw17 is the most abundant GSL in neutrophils. The cell-surface and intracellular presence of LacCer was determined quantitatively using anti-CDw17 mAbs in a flow cytometry assay. The quantified alterations in the level of CDw17 antigen expression are consistent with alterations in LacCer content, determined chemically. Our results show that CDw17 antigen expression defines successive stages in the maturation of the myeloid cell. The assessment of cell-surface and intracellular CDw17 expression may be useful in evaluating neutrophil physiological status.

Abnormal glycosylation of red cell membrane band 3 in the congenital disorder of glycosylation Ig.

A description is provided of the clinical presentation in an infant of the recently described congenital disorder of glycosylation type Ig, and the changes affecting glycosylation of red cell membrane band 3, the anion exchanger. It has been shown that the condition stems from a homozygous mutation within the human ortholog of yeast ALG12 gene, which encodes a dolichol-P-mannose:Man7GlcNAc2-PP-dolichol alpha,1-6 mannosyltransferase of the endoplasmic reticulum. The clinical phenotype included prominent central and peripheral manifestations in the CNS. Although the infant studied had no anemia, band 3 abnormally separated into two fractions upon electrophoresis. The chemical composition of the glycans of both fractions was analyzed in detail. The fraction with low electrophoretic mobility was moderately hypoglycosylated (by 27%) and its mannose content was normal. The fraction with high electrophoretic mobility was deeply carbohydrate deficient (by 64%) and had 1 mol mannose in excess but only three residues of N-acetylglucosamine. Glycophorin A was hypoglycosylated with respect to O-linked glycans. Glycosphingolipids of red cells were normal. We suggest that the incomplete biosynthesis of the N-linked glycan of band 3 was largely caused by the persistence of the 3-linked mannose residue on the 6-mannose arm of the trimannosyl moiety of the glycoprotein. It is remarkable that the changes recorded in band 3 have no clinical consequences. Band 3 alteration might serve as an additional indicator (some serum N-glycoproteins of hepatic origin are also indicative) of the congenital disorder of glycosylation type Ig.

Overexpression of the gene encoding GTP:mannose-1-phosphate guanyltransferase, mpg1, increases cellular GDP-mannose levels and protein mannosylation in Trichoderma reesei.

To elucidate the regulation and limiting factors in the glycosylation of secreted proteins, the mpg1 and dpm1 genes from Trichoderma reesei (Hypocrea jecorina) encoding GTP:alpha-D-mannose-1-phosphate guanyltransferase and dolichyl phosphate mannose synthase (DPMS), respectively, were overexpressed in T. reesei. No significant increases were observed in DPMS activity or protein secretion in dpm1-overexpressing transformants, whereas overexpression of mpg1 led to a twofold increase in GDP-mannose (GDPMan) levels. GDPMan was effectively utilized by mannnosyltransferases and resulted in hypermannosylation of secreted proteins in both N and O glycosylation. Overexpression of the mpg1 gene also increased the transcription of the dpm1 gene and DPMS activity. Our data indicate that the level of cellular GDPMan can play a major regulatory role in protein glycosylation in T. reesei.

Ceramides and glycosphingolipids in maturation process: leukemic cells as an experimental model.

Leukemic cells were used as experimental material to demonstrate changes in the content of GSLs during the development and maturation of neutrophils. The most abundant cellular GSL is LacCer. An elevation in the LacCer level occurs twice during the maturation process: initially, on formation of azurophil granules, and subsequently, (a more significant rise) on formation of specific granules. The formation of the latter is accompanied by an increase in the level of GalGalCer. During the maturation of myeloblasts, there is a simultaneous growth in the content of LacCer and GM3 as well as that of their common precursors, that is, free ceramides. Like other tumor cells, GM3 rich myeloblasts in the peripheral blood from patients with AML are characterized by shedding of gangliosides. The quantitative Cer/GlcCer ratio in these cells seems to be advantageous for the efficacy of chemotherapy in the induction of apoptosis. Myelo- and metamyelocytes achieve the highest level of GSLs. Their entry into the full maturity stage is accompanied by a decrease in the level of GSLs. Patterns of GSLs expression change greatly during development and maturation. However, with respect to the composition and content of GSLs, there are no significant differences between normal and leukemic mature neutrophils. At each stage of the development and maturation of myelogenous leukemic cells, as well as in normal mature neutrophils, there occurs the synthesis of the same molecular species both free ceramides and ceramide portions of LacCer, precursor of more complex GSLs.