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A Iolascon

Publications and source records attributed to A Iolascon.

At least 19 recordsLinked to original sources
PubMed2006

Estrogen-induced proliferation in cultured hepatocytes involves cyclin D1, p21(Cip1) and p27(Kip1).

The purpose of this study was to establish if estrogen-induced hepatocyte proliferation in vitro involves the cell cycle regulators cyclin D1, p21(Cip1), and p27(Kip1). Male rat hepatocytes were cultured in presence of 17-beta-estradiol (E2) +/- ICI-182780, a pure estrogen antagonist, and [3H]-thymidine, as required. DNA synthesis as well as p21(Cip1), p27(Kip1), and cyclin D1mRNA and protein levels were evaluated at different times (12, 24, 36, and 48 hours) of incubation. E2-increased DNA synthesis was correlated with cyclin D1 and p21(Cip1) (mRNA and protein) variations that were reversed by the addition of ICI-182780. p27(Kip1) protein levels progressively increased regardless of the presence of E2 or ICI-182780. Our data confirm that estrogens' stimulatory effect is related to their ability to increase cyclin D1 levels. The increase of p21(Cip1) is probably related to the reentry of hepatocytes in the quiescent state. p27(Kip1) protein is not able to arrest hepatocyte proliferation.

Animals↗
PubMed2005

The polymorphisms -318C>T in the promoter and 49A>G in exon 1 of CTLA4 and the risk of aplastic anemia in a Caucasian population.

Aplastic anemia (AA) is a rare disease with a major autoimmune pathogenetic component. CTLA4 is a T-lymphocyte surface molecule involved in the maintenance of immune tolerance. Some polymorphisms associated with a reduced expression of CTLA4, and thus presumably with increased tendency to autoimmunity, have been associated with various autoimmune diseases. In this study, we evaluated the distribution of the low expression polymorphisms -318C > T and 49A > G of CTLA4 in a population of 67 patients with acquired AA and in 100 normal controls. There was no difference in the distribution of the tested polymorphism between patients and controls and, within the patient group, between those who responded to immunosuppression vs those who did not respond. This study indicates that the polymorphisms -318C > T and 49A > G of CTLA4 do not affect the risk of developing AA and do not influence the response to immunosuppression.

Adolescent↗
PubMed2002

Cell division cycle control in embryonal and alveolar rhabdomyosarcomas.

In this study, we investigated the mRNA level of several genes involved in cell cycle regulation in alveolar (ARMS) and embryonal rhabdomyosarcomas (ERMS). p21(Cip1), Cyclin D1, Cyclin D2, Cyclin D3, CDK2, and CDK4 were evaluated by RT-PCR. All (13 out of 13) ERMS expressed the p21(Cip1) gene compared with only 40% (4 out of 10) of the ARMS. Moreover, the amount of p21(Cip1) mRNA was noticeably higher in the ERMS samples than in the positive ARMS specimens. p27(Kip1) protein were analysed by immunohistochemical and immunoblotting. A noticeable difference was observed, in that ERMS had higher amounts of the cell cycle inhibitor compared with the ARMS. Finally, treatment of two rhabdomyosarcoma cell lines, RH-30 and RD, with butyrate, resulted in complete growth inhibition and in the upregulation of the p21(Cip1) and p27(Kip1) levels. Our results demonstrate that ERMS have a much higher level of p27(Kip1) and p21(Cip1) than the alveolar types, explaining, at least in part, the distinct features and outcomes (i.e. a poor prognosis of the alveolar type) of the two forms of this childhood solid cancer. Moreover, the data on butyrate-treated cell lines suggest that the two genes are potential novel therapeutic targets for the treatment of rhabdomyosarcomas.

CDC2-CDC28 Kinases↗
PubMed2001

Natural history of congenital dyserythropoietic anemia type II.

Congenital dyserythropoietic anemia type II (CDA-II) is an autosomal recessive disease characterized by anemia, jaundice, splenomegaly, and erythroblast multinuclearity. The natural history of the disease is unknown. The frequency, the relevance of complications, and the use of splenectomy are poorly defined. This study examined 98 patients from unrelated families enrolled in the International Registry of CDA-II. Retrospective data were obtained using an appropriate questionnaire. The mean age at presentation was 5.2 +/- 6.1 years. Anemia was present in 66% and jaundice in 53.4% of cases. The mean age at correct diagnosis was 15.9 +/- 11.8 years. Twenty-three percent of patients for whom data were available developed anemia during the neonatal period, and 10 of these individuals required transfusions. Splenectomy produced an increased hemoglobin (P <.001) and a reduced bilirubin level (P =.007) in comparison with values before splenectomy. Preliminary data indicate that iron overload occurs irrespective of the hemochromatosis genotype. (Blood. 2001;98:1258-1260)

Adolescent↗
PubMed2001

Autosomal dominant macrothrombocytopenia in Italy is most frequently a type of heterozygous Bernard-Soulier syndrome.

A form of autosomal dominant macrothrombocytopenia is characterized by mild or no clinical symptoms, normal platelet function, and normal megakaryocyte count. Because this condition has so far received little attention, patients are subject to misdiagnosis and inappropriate therapy. To identify the molecular basis of this disease, 12 Italian families were studied by linkage analysis and mutation screening. Flow cytometry evaluations of platelet membrane glycoproteins (GPs) were also performed. Linkage analysis in 2 large families localized the gene to chromosome 17p, in an interval containing an excellent candidate, the GPIbalpha gene. GPIbalpha, together with other proteins, constitutes the plasma von Willebrand factor (vWF) receptor, which is altered in Bernard-Soulier syndrome (BSS). In 6 of 12 families, a heterozygous Ala156Val missense substitution was identified. Platelet membrane GP studies were performed in 10 patients. Eight were distinguished by a reduction of GPs comparable to that found in a BSS heterozygous condition, whereas the other 2, without the Ala156Val mutation, had a normal content of platelet GPs. In conclusion, the current study provides evidence that most (10 of 12) patients with an original diagnosis of autosomal dominant macrothrombocytopenia shared clinical and molecular features with the heterozygous BSS phenotype. The remaining 2 affected subjects represented patients with "true" autosomal dominant macrothrombocytopenia; the GPIb/IX/V complex was normally distributed on the surface of their platelets. Thus, the diagnosis of heterozygous BSS must always be suspected in patients with inherited thrombocytopenia and platelet macrocytosis.

Adolescent↗
PubMed2001

Bone marrow transplantation in a case of severe, type II congenital dyserythropoietic anaemia (CDA II).

Type II congenital dyserythropoietic anaemia (CDA-II or HEMPAS) is an autosomal recessive disorder, representing the most frequent form of congenital dyserythropoiesis. It is characterised by normocytic anaemia, variable jaundice and hepato-splenomegaly. Gallbladder disease and secondary haemochromatosis are frequent complications. We report a case characterised by severe transfusion-dependent anaemia. The proband inherited CDA-II in association with beta-thalassaemia trait. Splenectomy did not abolish the transfusion dependence and this, in association with poor compliance to iron-chelation therapy, prompted us to consider bone marrow transplantation (BMT) from his HLA-identical sibling. The preparative regimen included busulfan, thiotepa and fludarabine, and graft-versus-host disease prophylaxis consisted of cyclosporin A and short-term methotrexate. Engraftment of donor cells was prompt and the post-transplant course uncomplicated. The patient is alive and transfusion-independent 36 months after allograft. This is the first case of severe CDA-II to undergo BMT. Analysis of this pedigree suggests that interaction with beta-thalassaemia enhanced the clinical severity of CDA-II, making BMT an attractive therapy for patients with transfusion dependence.

Adult↗
PubMed2001

Reversible erythrocyte skeleton destabilization is modulated by beta-spectrin phosphorylation in childhood leukemia.

The erythrocyte skeleton plays an essential role in determining the shape and deformability of the red cell. Disruption of the interaction between components of the red cell membrane skeleton may cause loss of structural and functional integrity of the membrane. Several observations based on studies in vitro strongly suggest that phosphorylation may modify interactions between proteins, leading to a reduced affinity. In particular, increased phosphorylation of beta-spectrin decreases membrane mechanical stability. In order to investigate the presence of membrane protein defects we investigated the erythrocyte membrane protein composition and phosphorylation in 22 children with leukemia at diagnosis and during the remission phase. Sixteen children had acute lymphoblastic leukemia (ALL), three had chronic myeloid leukemia (CML) and three had acute myeloid leukemia (AML). Ten patients (eight ALL and two CML) displayed elliptocytosis and poikilocytosis, an increase of spectrin dimers (41.8 +/- 15.6) and an enhanced phosphorylation of beta-spectrin (108 +/- 15%) at diagnosis. These alterations disappeared during the remission phase. This is the first demonstration of a reversible erythrocyte membrane alteration in leukemia. Since the beta-spectrin phosphate sites are located near the C-terminal region and close to the head of the beta-chain that is involved in dimer-dimer interaction, we supposed that the beta-chain phosphorylation has an effect upon the interactions between spectrin dimers, ie the tetramerization process. The weakening of this process should be responsible for the presence of elliptocytes and poikilocytes as reported in hereditary elliptocytosis and pyropoikilocytosis.

Acute Disease↗
PubMed2001

Clinical and molecular evaluation of non-dominant hereditary spherocytosis.

About 75% of hereditary spherocytosis (HS) patients have the autosomal dominant form of the disease, whereas both parents of the remaining HS patients are clinically and haematologically normal. These patients could have either the autosomal recessive form of the disease or a de novo mutation. We studied 80 randomly chosen, Italian HS children with normal parents. They had different clinical phenotypes (16 mild, 40 moderate, 16 moderately severe and eight severe). These patients were screened for the occurrence of ankyrin or beta-spectrin de novo mutations. To search for ankyrin de novo mutations affecting mRNA accumulation, we studied a (AC)(n) microsatellite located in the non-coding sequence of the last exon of the ankyrin gene, and four different exonic polymorphisms in the beta-spectrin gene were utilized for the detection of de novo mutations influencing beta-spectrin mRNA stability. They were also screened for the presence of alpha-spectrin(LEPRA) as well as for the mutation -108T-->C in the ankyrin promoter, two variants previously found in some cases of genuinely recessive HS. Twenty-five patients showed ankyrin de novo mutations and 10 HS subjects had beta-spectrin de novo mutations. Furthermore, we found five patients to be heterozygous for alpha-spectrin(LEPRA) and one heterozygous for the mutation in the ankyrin promoter. Therefore, a molecular diagnosis was achieved in about 50% of the cases. Our data demonstrate that, among HS patients with normal parents, de novo dominant mutants are six times more common than recessive mutations. These results should be considered in view of the genetic counselling of a normal couple with a HS child.

Adolescent↗
PubMed2001

Flow-cytometric analysis of erythrocytes and reticulocytes in congenital dyserythropoietic anaemia type II (CDA II): value in differential diagnosis with hereditary spherocytosis.

Congenital dyserythropoietic anaemia type II (CDA II) is the most common congenital dyserythropoietic anaemia. CDA II is frequently misdiagnosed as Hereditary Spherocytosis (HS) due to the presence of mild chronic haemolytic anaemia with splenomegaly, increased osmotic fragility, and presence of microspherocytes. Accurate diagnosis of CDA II is important to prevent severe iron overload. Erythrocyte and reticulocyte indices were assessed in 10 patients from six families with CDA II, 18 patients from eight families with HS, and 50 normal controls. Characteristic increases in distribution width were present in CDA II for cell volume (RDW, anisocytosis) and in HS for cell haemoglobin concentration (HDW, anisochromia), resulting in an RDW/HDW ratio which was significantly greater in CDA than HS (P < 0.0002). A cut-off value for RDW/HDW of 5.34 resulted in 89% sensitivity and 70% specificity in distinguishing CDA II from HS. Distribution width for cell haemoglobin content of reticulocytes (CHDWr) was characteristically increased in CDA II, resulting in a CHDW/CHDWr ratio significantly lower in CDA II than HS (P < 0.0002). A cut-off value of 0.98 provided 89% sensitivity and 80% specificity in distinguishing CDA II from HS. These differences in distribution widths of flow-cytometric parameters of reticulocytes and mature erythrocytes reflect the different pathogeneses of the two diseases and are helpful for the differential diagnosis of these two conditions.

Adolescent↗
PubMed2001

Renal vein thrombosis in a newborn with prothrombotic genetic risk factors.

Environmental and genetic risk factors interact to cause venous thromboembolism. Renal vein thrombosis in the newborn has been frequently associated with "risk factors" as catheters, surgery or trauma, but it has also been demonstrated a pathogenetic role of genetic prothrombotic risk factors, i.e. activated protein C resistance and FV Leiden. The treatment of neonatal venous thrombosis varies worldwide and different approaches have been proposed. We present a case of renal vein thrombosis in a female newborn with normal plasma levels of protein C, protein S and antithrombin III, but with her genotype characterized by the presence of three prothrombotic risk factors: factor V Leiden, methylentetrahydrofolate reductase and platelet glycoprotein IIIa polymorphisms. The treatment with recombinant tissue plasminogen determined complete thrombus dissolution.

Factor V↗
PubMed2000

Pleiotropic syndrome of dehydrated hereditary stomatocytosis, pseudohyperkalemia, and perinatal edema maps to 16q23-q24.

Dehydrated hereditary stomatocytosis (DHS) is a rare genetic disorder of red cell permeability to cations, leading to a well-compensated hemolytic anemia. DHS was shown previously to be associated in some families with a particular form of perinatal edema, which resolves in the weeks following birth and, in addition, with pseudohyperkalemia in one kindred. The latter condition was hitherto regarded as the separate entity, "familial pseudohyperkalemia." DHS and familial pseudohyperkalemia are thought to stem from the same gene, mapping to 16q23-q24. This study screened 8 French and 2 American families with DHS. DHS appeared to be part of a pleiotropic syndrome in some families: DHS + perinatal edema, DHS + pseudohyperkalemia, or DHS + perinatal edema + pseudohyperkalemia. If adequately attended to, the perinatal edema resolved spontaneously after birth. Logistic regression showed that increased mean corpuscular volume and mean corpuscular hemoglobin concentration were the parameters best related to DHS. In patients in whom cation fluxes were investigated, the temperature dependence of the monovalent cation leak exhibited comparable curves. Specific recombination events consistently suggested that the responsible gene lies between markers D16S402 and D16S3037 (16q23-q24). The 95% confidence limits (Z(max) >/= 3.02) spanned almost the complete 9-cM interval between these 2 markers.

Adolescent↗
PubMed2000

p27Kip1 accumulation is associated with retinoic-induced neuroblastoma differentiation: evidence of a decreased proteasome-dependent degradation.

Development of human neuroblastoma is due to an arrest in the differentiation program of neural crest sympathoadrenal progenitor cells. However, neuroblastomas, as well as their derived cell lines, maintain the potentiality of terminal differentiation. We investigated the molecular mechanisms by which retinoic acid, a molecule introduced in clinical trials for chemotherapy, induces differentiation in neuroblastoma cell lines. Our findings demonstrate that the retinoic acid-dependent growth arrest of LAN-5 neuroblastoma cell line is associated to a very large accumulation (>tenfold) of p27Kip1 protein, a cyclin-dependent kinase inhibitor; the protein binds and inhibits cyclin-dependent kinase 2, 4 and 6 activities, thus hampering pRb and p107 phosphorylation. p27Kip1 build-up was observable as an early phenomenon (12 - 24 h) after retinoic exposure and resulted in a time-dependent accumulation of high quantities of a free p27Kip1 form. Furthermore, retinoic treatment causes an increase of cyclin-dependent kinase 5 level and activity; however, immunoprecipitation studies proved the absence of interaction with p27kip1. No noticeable variation of other components of G1 phase cell cycle engine was observed. Pulse-chase experiments showed a remarkable elongation of p27Kip1 half-life in retinoic-treated LAN-5, while no enhancement of p27Kip1 gene expression and of the translational efficiency of its messenger RNA were demonstrated. In vivo degradation of p27Kip1 was sensitive to two highly specific proteasome inhibitors, LLnL and lactacystin, while the calpain inhibitor II ALLM and the cysteine protease inhibitor E64 did not modify the level of the protein. LLnL treatment caused a very rapid (2 h) build-up of the Cdk inhibitor content and the accumulation of higher molecular weight anti-p27Kip1 immunoreactive bands, which probably represent ubiquitinated forms of the protein. Finally, in vitro experiments demonstrated that extracts prepared from retinoic-treated LAN-5 cells degraded recombinant p27Kip1 at a rate remarkably slower than the untreated cells. Our results indicate that retinoic acid strongly increases p27Kip1 levels by down-regulating the ubiquitin-proteasome p27Kip1 degrading pathway.

Cell Cycle↗
PubMed2000

Characterization of the CYP21 gene 5' flanking region in patients affected by 21-OH deficiency.

In order to test the hypothesis that mutations in the 5' non-coding region of CYP21 gene could contribute to the various spectrum of disease presentation due to 21-OH deficiency, the 400bp nucleotide sequence upstream of the ATG codon of CYP21 gene has been characterized in 28 CAH patients who have previously been genotyped by screening for the ten most frequent CYP21 mutations. Six specific sequence variations (-4C-->T, -73C-->T, -295T-->C, -294A-->C, -283A-->G, -281T-->G) have been identified in this region of CYP21 gene in 3 out of 28 21-OH deficient patients for whom the coding region mutations have been previously identified. Three of these mutations, -295T-->C, -294A-->C, -283A-->G, are apparently generated by a gene-conversion event, thus giving first evidence that this mechanism also applies to the 5' untranslated region of CYP21 gene in 21-OH deficiency. Four other sequence changes, identified at nucleotide position -279, -331, -350 and -353, could be referred to as normal since they are present also in healthy subjects. It may not be excluded that some of the newly-identified single nucleotide changes in the regulatory region could have a modulatory effect on the CYP21 gene transcriptional activity thus affecting the clinical outcome.

5' Untranslated Regions↗
PubMed2000

Gilbert's syndrome accounts for the phenotypic variability of congenital dyserythropoietic anemia type II (CDA-II).

The molecular basis for the considerable variation of serum bilirubin levels and the incidence of gallstone formation in patients with congenital dyserythropoietic anemia (CDA) type II are unknown. We show that the combined effect of an increased bilirubin load caused by dyserythropoiesis in CDA II and decreased bilirubin conjugation caused by reduced expression of uridine diphosphate glucuronosyl transferase (UGT1A) would increase the risk of hyperbilirubinemia (P <.005) and gallstone formation (chi(2): P <. 001). The rate of gallstone formation in patients with CDA II is 4. 75-fold the rate of patients without Gilbert's syndrome, and gallstone diagnosis occurs at a younger age (P < 0.01). These findings should be considered during the follow-up of patients with CDA II.

Adolescent↗
PubMed2000

Transfusion-dependent congenital dyserythropoietic anaemia with intraerythroblastic inclusions of a non-globin protein.

The congenital forms of dyserythropoiesis comprise a group of hereditary disorders characterized by ineffective erythropoiesis as the predominant mechanism of anaemia and morphologically abnormal erythroblasts. Up to now three major forms and four variants have been described. Group VII is characterized by dyserythropoiesis with intraerythroblastic precipitation of a non-globin protein. Here we described a case of dyserythropoietic anaemia presenting neonatally and requiring regular blood transfusions. Optical and electronic microscopy studies confirmed that this case was very similar to those in two previously reported transfusion-dependent patients with an unusual type of congenital dyserythropoietic anaemia.

Anemia, Dyserythropoietic, Congenital↗
PubMed2000

Mutations in MYH9 result in the May-Hegglin anomaly, and Fechtner and Sebastian syndromes. The May-Heggllin/Fechtner Syndrome Consortium.

The autosomal dominant, giant-platelet disorders, May-Hegglin anomaly (MHA; MIM 155100), Fechtner syndrome (FTNS; MIM 153640) and Sebastian syndrome (SBS), share the triad of thrombocytopenia, large platelets and characteristic leukocyte inclusions ('Döhle-like' bodies). MHA and SBS can be differentiated by subtle ultrastructural leukocyte inclusion features, whereas FTNS is distinguished by the additional Alport-like clinical features of sensorineural deafness, cataracts and nephritis. The similarities between these platelet disorders and our recent refinement of the MHA (ref. 6) and FTNS (ref. 7) disease loci to an overlapping region of 480 kb on chromosome 22 suggested that all three disorders are allelic. Among the identified candidate genes is the gene encoding nonmuscle myosin heavy chain 9 (MYH9; refs 8-10), which is expressed in platelets and upregulated during granulocyte differentiation. We identified six MYH9 mutations (one nonsense and five missense) in seven unrelated probands from MHA, SBS and FTNS families. On the basis of molecular modelling, the two mutations affecting the myosin head were predicted to impose electrostatic and conformational changes, whereas the truncating mutation deleted the unique carboxy-terminal tailpiece. The remaining missense mutations, all affecting highly conserved coiled-coil domain positions, imparted destabilizing electrostatic and polar changes. Thus, our results suggest that mutations in MYH9 result in three megakaryocyte/platelet/leukocyte syndromes and are important in the pathogenesis of sensorineural deafness, cataracts and nephritis.

Alleles↗
PubMed2000

Localisation of the gene responsible for fechtner syndrome in a region <600 Kb on 22q11-q13.

Fechtner syndrome is an autosomal dominant disorder which has been thought to be a variant of Alport syndrome. It is characterised by nephritis, sensorineural hearing loss and eye abnormalities, as well as by macrothrombocytopenia and polymorphonuclear inclusion bodies. Recently, the Fechtner syndrome has been mapped in a 5.5 Mb region on the long arm of chromosome 22 by linkage analysis in an extended Israeli family. We describe here the genetic refinement of the Fechtner critical interval to a region less than 600 Kb by linkage analysis performed in a large Italian pedigree. The presence of several recombination events allowed the disease gene to be localised between markers D22S278 and D22S426, in a region containing only two non-recombinant markers, D22S1173 and D22S283. This interval, spanning <600 Kb on genomic DNA, has been entirely sequenced and contains six known and three putative genes.

Abnormalities, Multiple↗