Biomedical subjects

G Basso

Publications and source records attributed to G Basso.

At least 55 records · Page 3Linked to original sources

PubMed1998

The guanine triphosphatase (GTPase) activating protein (GAP)-related domain of the neurofibromatosis type 1 gene is not mutated in neural crest-derived sporadic tumours.

We conducted a mutation analysis of the most conserved region of the neurofibromatosis type 1 (NF1) gene, the guanine triphosphatase (GTPase) activating protein (GAP)-related domain (NF1 GRD), to which the function of tumour suppressor is attributed. Sixty primary neuroectodermal tumours were analysed. The rationale for the study was based on the likelihood of finding structural alterations resulting in loss of function of this region in tumours of neuroepithelial tissues, where the activity of neurofibromin seems to be crucial in regulating the mechanisms of signal transduction and cell transformation mediated by p21 ras. Following analysis of the whole NF1 GRD sequence, no mutations were identified in the tumours analysed. We conclude that the loss of NF1 gene tumour suppressor function, that might lead or contribute to the development of malignancies in neuroectodermal tissues, is not due to structural abnormalities of the region of the gene which interacts with p21 ras.

Base Sequence↗

PubMed1998

Autologous bone marrow transplantation for treatment of isolated central nervous system relapse of childhood acute lymphoblastic leukemia. AIEOP/FONOP-TMO group. Associzione Italiana Emato-Oncologia Pediatrica.

The purpose of this study was to assess the role of ABMT in children with ALL who are in 2nd CR after an early isolated CNS relapse. All children experiencing an isolated CNS relapse at 10 AIEOP centers (Associazione Italiana Emato-Oncologia Pediatrica) from 1986 to 1992 were eligible for this study. The series included 69 patients who relapsed within 3 years from diagnosis: 19 underwent ABMT, nine patients underwent ALLO-BMT from an HLA-identical sibling, and 41 received conventional chemotherapy (CHEMO). Statistical analysis was performed using a Cox's regression model, adjusting for the waiting time before transplantation and prognostic factors. The 5 years DFS was 56.3% (s.e. 12.3) for patients in the ABMT group. This compared favorably with the poor result (12.6% (s.e. 5.9)) seen in the CHEMO group. The risk of failures was reduced by one-third in the ABMT group as compared to the CHEMO group in the multivariate analysis (P < 0.01). In the ALLO group four out of nine patients were in CCR 4-5 years post-transplant. This study suggests that ABMT may also represent a valuable therapeutic choice for patients lacking a matched familiar donor in 2nd CR after an early isolated CNS relapse.

Adolescent↗

PubMed1998

Autologous bone marrow transplantation for childhood acute lymphoblastic leukaemia in Italy. AIEOP/FONOP-TMO Group. Italian Association of Paediatric Haemato-Oncology.

From January 1984 to December 1994, ABMT was performed on 154 children (101 males, 53 females; median age 10, range 3-21 years) with ALL and registered for BMT by the AIEOP (Italian Association of Paediatric Haemato-Oncology). All patients were in CR: 98 were in 2nd CR and 56 were in >2nd CR. Fifteen children (9.7%) died of transplant-related mortality. Ninety-five patients (61.6%) relapsed at a median of 5 (range 1-42) months after ABMT. The 8-year EFS according to pre-BMT status was 34.6% (s.e. 4.9) for 2nd CR patients and 10.6% (s.e. 5.6) for patients in >2nd CR. By univariate analysis, site of relapse (isolated extramedullary (IE) vs BM: EFS = 68.5% vs 18.2%; P < 0.0001) and TBI containing regimen (TBI vs no TBI: EFS = 48.1 vs 15.4%; P = 0.0023) were significant factors for 2nd CR patients. When the 2nd CR subset with BM involvement was analysed, TBI became insignificant (EFS = 25.4 vs 11.8%). No factors influenced EFS in patients in >2nd CR. By multivariate analysis, site of relapse was the only significant factor in 2nd CR patients (P < 0.0001). In conclusion, ABMT is an effective treatment after one early IE relapse. Few patients can be rescued after BM relapse.

Adolescent↗

PubMed1998

Immunophenotype of adult and childhood acute promyelocytic leukaemia: correlation with morphology, type of PML gene breakpoint and clinical outcome. A cooperative Italian study on 196 cases.

Acute promyelocytic leukaemia (APL), characterized by a specific PML-RARalpha fusion gene resulting from translocation t(15;17) and by a high response rate to differentiation therapy with all-trans retinoic acid, presents clinical (varying WBC counts, age and treatment outcome), morphological (hypergranular M3 and hypogranular M3V) and molecular (three isoforms of PML breakpoint) heterogeneity. We correlated leukaemic immunophenotype with these aspects in 196 molecularly confirmed APLs (63 children and 133 adults) in Italy. The bcr3 isoform (P = 0.05) and FAB M3V (P = 0.05) were more frequent in children. We confirmed in APL an immunophenotype characterized by frequent expression of CD13, CD33 and CD9 and rare expression of HLA-DR, CD10, CD7 and CD11b. However, we recognized CD2 in 28%, CD34 in 23% and CD19 in 11% of cases and demonstrated by double labelling that CD34 and CD2 may be co-expressed. CD2, CD34 and CD19 were significantly intercorrelated, and variably associated to other features: CD2 and CD34 with PML bcr3 (P < 0.001 and P < 0.001, respectively) and with M3V (P < 0.001 and P = 0.002), whereas only CD19 was directly correlated with WBC counts and only CD2 positively influenced CR rate (logistic model) and event-free survival (Cox model). We conclude that immunophenotype plays a role in the determination of the biological and clinical heterogeneity of childhood and adult APL.

Adolescent↗

PubMed1998

Hepatoblastoma: DNA nuclear content, proliferative indices, and pathology.

Hepatoblastoma (HB) is the most frequent malignant liver tumor in infancy, and both its biological features and its prognostic behavior are still under investigation. DNA content and proliferative activity of the tumor have been considered as biological parameters related to the tumor's aggressiveness. The present study attempts to investigate the possible association between histologic subtype, DNA content, and proliferative indices in HB. DNA content and the proportion of cells in the S-phase were assessed by flow cytometry in 34 cases of HB (14 prior to chemotherapy, 20 after chemotherapy), using formalin-fixed, paraffin-embedded archival samples. The proliferative cell nuclear antigen (PCNA) labeling index was also evaluated by immunohistochemistry, and both the flow cytometry (FC) and the immunohistochemical data were correlated with tumor pathology. A significant association was found between histological type, DNA content and the percentage of cells in the S-phase, with aneuploidy and the highest proportions of S-phase cells significantly associated with embryonal tumors. The PCNA labeling index was found to be significantly higher in embryonal than in fetal phenotype. The biological heterogeneity of HB is Confirmed by the different nuclear content of the fetal (diploid) and embryonal (aneuploid) epithelial components of the tumor, also ruling out the likelihood of fetal (diploid) clones deriving from the embryonal (aneuploid) neoplastic cells. Since the highly proliferative neoplastic clones (i.e., embryonal) are thought to be more sensitive to antimitotic drugs, further studies are indicated to determine the relationship between ploidy, proliferative indices and chemoresponsiveness.

Child↗

PubMed1998

Microsatellite analysis in childhood acute lymphoblastic leukemia.

BACKGROUND AND OBJECTIVE: Genetic alterations, including genomic instability, represent possible steps towards a malignant transformation. One approach to delineate replication errors in cancer cells is to determine alterations of microsatellites that are short tandem repeat sequences dispersed throughout the human genome. We have investigated whether genomic instability may be a possible event in the leukemogenic process by evaluating the pattern of instability in 41 cases of childhood acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS: Eighty-two samples of genomic DNA (41 at diagnosis and 41 at remission) were analyzed by PCR with microsatellite markers chosen on five different chromosomes (2, 10, 11, 13, 18) known to be frequently involved in tumors of various origins. Since deletions of the short arm of chromosome 12 are relatively common in children with ALL, we also analyzed one region flanked by the microsatellite marker D12S308 on 12p. This area encompasses a genetic locus which contains the putative suppressor gene KIP1. RESULTS: A pattern of MI at one or two loci on different chromosomes could be documented in 4 of the 41 cases analyzed (9.7%). Three were common ALL and 1 was a T-ALL. One case showed two concomitant sites of instability, while 1 revealed two additional bands by using simultaneously microsatellite markers D2S123 and D18S58. INTERPRETATION AND CONCLUSIONS: These results indicate that genetic instability of microsatellite repeat sequences occurs in a proportion of childhood ALL. Mismatched repair errors documented in hereditary and sporadic solid tumors may thus be involved in hematological malignancies. While in such cases the pattern of genomic instability appears indicative of a mutator phenotype and of a potential predisposition towards a leukemic transformation, other genomic loci close to cytogenetic and molecular alterations known to occur in ALL need to be investigated in depth in cases with an apparently non mutated phenotype.

Child↗

PubMed1998

Use of recombinant granulocyte colony-stimulating factor in Fanconi's anemia.

BACKGROUND AND OBJECTIVE: Granulocyte colony-stimulating factor (G-CSF) has been shown to improve the neutropenic status of patients with bone marrow failure. The side effects in prolonged treatment still need to be determined. DESIGN AND METHODS: We have studied the efficacy and the long-term side effects of G-CSF in four patients with Fanconi's anemia and severe neutropenia. RESULTS: Three patients responded with an increase in their absolute neutrophil count; neither improvement in platelet count and hemoglobin concentration nor effect on transfusion requirements was seen. CFU-GM and BFU-E were undetectable before, during and after treatment. Responders showed an important reduction in number and severity of infections, with a marked improvement of clinical status. The fourth patient developed acute myeloid leukemia after 4 weeks of G-CSF treatment. During maintenance, one patient was treated with G-CSF for 18 months, until she received bone marrow transplantation, without presenting side effects. In the second responding patient G-CSF treatment was stopped because of appearance of immature cells in peripheral blood and myeloid blasts in bone marrow. The third responding patient presented immature peripheral myeloid cells during the third year of G-CSF treatment: disappearance of immature cells was observed after G-CSF reduction. In two cases FISH analysis revealed monosomy 7 after G-CSF treatment. INTERPRETATION AND CONCLUSIONS: G-CSF use results in an improvement of clinical status, but long term administration may cause adverse experiences and requires a close hematological monitoring.

Adolescent↗

PubMed1998

Increased levels of a chromosome 21-encoded tumour invasion and metastasis factor (TIAM1) mRNA in bone marrow of Down syndrome children during the acute phase of AML(M7).

Children with Down syndrome (DS) have a 10-20-fold increased risk of acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML), compared to non-DS children. The myeloid leukemia that accounts for nearly 50% of DS leukemias is usually the otherwise uncommon megakaryoblastic type (AML-M7). Though an etiological role of trisomy 21 in leukemogenesis has been suggested, the expression of genes on chromosome 21 in relation to trisomy, DS, and specific DS phenotypes such as leukemia is poorly understood. We used a heterologous-mimic competitive RT-PCR technique to measure the mRNA levels of a chromosome 21 tumour invasion and metastasis factor (TIAM1) directly in bone marrow samples of DS leukemic patients. In the limited number of cases analysed so far, we found TIAM1 mRNA levels in the DS AML-M7 samples of bone marrow taken in the acute phase of the disease (presentation or relapse, n=8) to be highly significantly raised, nearly threefold, compared to that measured in the remission samples or normal individuals (normals + remissions, n=10).

Acute Disease↗

PubMed1998

Intensive BFM chemotherapy for childhood ALL: interim analysis of the AIEOP-ALL 91 study. Associazione Italiana Ematologia Oncologia Pediatrica.

BACKGROUND AND OBJECTIVE: Since 1988 the AIEOP has used BFM-based chemotherapy for childhood ALL. Current organization and results and role of cranial irradiation in the AIEOP-ALL 91 study are reported. DESIGN AND METHODS: From 1991 to 1995, 1194 children (< 15 years) with non-B ALL, were enrolled and assigned to the standard risk [SR: age > 1 year, non-T-ALL, BFM risk factor (RF) < 0.8], intermediate risk (IR: RF > or = 0.8 but < 1.7, or with RF < 0.8 and age < 1 year, or T-ALL), or high risk [HR: RF > or = 1.7, or t(9;22), or t(4;11) or prednisone poor response or late response or CNS involvement] groups. All patients received initially protocol Ia. Thereafter SR patients received HD-MTX 2 g/m2, a modified protocol II, and continuation therapy with triple intrathecal chemotherapy (TIT); IR patients received protocol Ib, HD-MTX 5 g/m2, protocol II and continuation therapy with TIT; HR patients received 9 polychemotherapy blocks, cranial irradiation and continuation therapy. Duration of treatment was 24 months. A randomized study was conducted to evaluate the impact of high-dose asparaginase in non high risk patients: the results of this study cannot be disclosed yet. RESULTS: One thousand one hundred and fifty-two (96.5%) patients achieved CR. Overall EFS (SE) at 5-years was 71.0% (1.4), with a survival of 80.3% (1.3). Relapse occurred in 262 children (21.9%), either in the marrow (n = 192 isolated and 32 with other sites, 18.7%), in the CNS (n = 18, 1.5%), or elsewhere (n = 20, 1.7%). 5-year EFS (SE) was 83.3% (2.4) in SR, 74.7% (1.8) in IR, and 39.7% (3.5) in HR groups, respectively. INTERPRETATION AND CONCLUSIONS: Overall cure rate was higher than in the previous AIEOP-ALL 88 study. Treatment intensification with polychemotherapy blocks did not improve results in HR. Cranial irradiation can be safely omitted in over 80% of children treated with BFM based chemotherapy.

Adolescent↗

PubMed1998

Softgel capsule technology as an enhancer device for the absorption of natural principles in humans. A bioavailability cross-over randomised study on silybin.

In order to evaluate if a patented soft gelatine capsule could improve the bioavailability of silybin (CAS 22888-70-6) in comparison to a hard shell capsule, an open, single dose, two-way, balanced cross-over study, was performed. The study was conducted on 12 healthy subjects (6 M and 6 F). 80 mg of silybin in a 1:2 complex with phosphatidylcholine was administered. Blood was sampled from the subjects in two occasions at the following times after drug administrations: 0 (sample before dosing), 1, 2, 3, 4, 6 and 8 h. The pharmacokinetic parameters calculated from the results of the plasma analyses demonstrated that the mean values of both Cmax and AUC0-1 were increased when the patented soft gelatine capsule formulations were administered (i.e. Cmax more than 3-fold and AUC0-1 more than 2-fold).

Adolescent↗

PubMed1998

American cutaneous leishmaniasis in the State of São Paulo, Brazil--epidemiology in transformation.

American cutaneous leishmaniasis, a disease of great worldwide importance, especially on the American continent, has had its epidemological modifications. These are revised and discussed in view of the current situation of recent increase in its incidence in regions with low morbidity since 1950, where no apparent cause that would justify an epidemic outbreak could be found. We analysed the causes of these alterations and the profile now seen in the State of Sao Paulo, Brazil.

Animals↗

PubMed1998

Clinical relevance of CD10 expression in childhood ALL. The Italian Association for Pediatric Hematology and Oncology (AIEOP).

BACKGROUND AND OBJECTIVE: Previous studies have considered the prognostic significance of CD10 expression in childhood acute lymphoblastic leukemia (ALL) and showed its linkage to a more favorable prognosis. The aim of this study was to assess the independent significance of CD10 expression in a large population of ALL patients. DESIGN AND METHODS: We revised the independent clinical relevance of CD10 expression in 2038 children with acute lymphoblastic leukemia (ALL), who were consecutively entered in 4 sequential trials of the Italian Association for Pediatric Hematology and Oncology (i.e. AIEOP studies 82, 87, 88, 91); 1142 were males and 896 females, age ranged between 1 and 14 years (yrs) at diagnosis. Of the whole group, 1471 children (72.2%) were defined as having standard risk, 567 (27.8%) as having a high risk. RESULTS: CD10 was detected in blast cells from 1706 of 1784 (95.6%) patients with B-lineage ALL and 46 of 254 (18.1%) with T-cell ALL. In the B-lineage subgroup CD10 expression was associated with presenting features such as age < 9 yrs and inclusion in the standard risk category. No significant differences were found between CD10+ and CD10- cases in T-lineage ALL, concerning presenting features, except for FAB L2 in the former group. We compared the event-free survival (EFS) rates for patients with T-ALL or B-lineage ALL, regarding CD10 positivity, overall and by individual study. Patients with T-ALL fared worse than those with B-lineage ALL (5 and 10 yrs EFS: 46.8% vs. 68.5% and 44.5% vs. 63.7% respectively, p = 0.0001). In multivariate analysis of B-lineage subgroup poorer EFS was associated with male sex, higher WBC (> or = 20 x 10(9)/L), age > 9 yrs. Only WBC > or = 20 x 10(9)/L and age > 9 yrs were parameters linked to poorer EFS in the T-lineage subgroup. Finally, we compared EFS rates for four groups of patients categorized as having high or standard risk, and according to CD10+ and CD10- expression. High-risk patients fared statistically worse than standard risk patients both in the CD10- and in the CD10+ groups (42% vs. 50.7% and 63.6% vs. 66.8%, respectively). INTERPRETATION AND CONCLUSIONS: CD10 expression does not have independent prognostic significance in either the larger subgroup of B-ALL patients or in T-cell ALL.

Adolescent↗

PubMed1998

Cytofluorimetric analysis of CD34 cells.

The cytofluorimetric enumeration of CD34-positive cells is a useful method for measuring haematopoietic stem cells. The large variation of results between different laboratories, in multicenter quality control studies, could be due to multiple technical problems. CD34 analysis must be performed in whole blood and the NH4Cl or the NH4Cl-derived reagents give the best results in the lysis procedure. The monoclonal antibody for CD34 detection must be a class III, if possible PE-conjugated. Any differences were found in the absolute CD34 count using different analysis protocols: Milan, ISHAGE, Dutch, or a commercial kit, when the sample is fresh and in good viable condition. The multiparametric approach, using three or four colours simultaneously, could be required in scoring apheresis products from patients with CD34-positive blast cells (ie ALL of B cell origin) and in deciding the optimum time to start the leukapheresis, choosing, with an equal CD34 number, the moment at which the highest number of more immature progenitor cells (CD38-negative or dim, CD90-positive) is present.

Antigens, CD34↗

PubMed1997

Incidence and clinical relevance of TEL/AML1 fusion genes in children with acute lymphoblastic leukemia enrolled in the German and Italian multicenter therapy trials. Associazione Italiana Ematologia Oncologia Pediatrica and the Berlin-Frankfurt-Münster Study Group.

The molecular approach for the analysis of leukemia associated chromosomal translocations has led to the identification of prognostic relevant subgroups. In pediatric acute lymphoblastic leukemia (ALL), the most common translocations, t(9;22) and t(4;11), have been associated with a poorer clinical outcome. Recently the TEL gene at chromosome 12p13 and the AML1 gene at chromosome 21q22 were found to be involved in the translocation t(12;21)(p13;q22). By conventional cytogenetics, however, this chromosomal abnormality is barely detectable and occurs in less than 0.05% of childhood ALL. To investigate the frequency of the molecular equivalent of the t(12;21), the TEL/AML1 gene fusion, we have undertaken a prospective screening in the running German Berlin-Frankfurt-Münster (BFM) and Italian Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) multicenter ALL therapy trials. We have analyzed 334 unselected cases of pediatric ALL patients consecutively referred over a period of 5 and 9 months, respectively. The overall incidence of the t(12;21) in pediatric ALL is 18.9%. The 63 cases positive for the TEL/AML1 chimeric products ranged in age between 1 and 12 years, and all but one showed CD10 and pre-B immunophenotype. Interestingly, one case displayed a pre-pre-B immunophenotype. Among the B-lineage subgroup, the t(12;21) occurs in 22.0% of the cases. Fifteen of 61 (24.6%) cases coexpressed at least two myeloid antigens (CD13, CD33, or CDw65) in more than 20% of the gated blast cells. DNA index was available for 59 of the 63 TEL/AML1 positive cases; a hyperdiploid DNA content (> or = 1.16) was detected in only four patients, being nonhyperdiploid in the remaining 55. Based on this prospective analysis, we retrospectively evaluated the impact of TEL/AML1 in prognosis by identifying the subset of B-lineage ALL children enrolled in the closed German ALL-BFM-90 and Italian ALL-AIEOP-91 protocols who had sufficient material for analysis. A total of 342 children were investigated for the presence of TEL/AML1 fusion gene and 99 cases (28.9%) were positive. The patients expressing the TEL/AML1 fusion mRNA appeared to have a better event-free survival (EFS) than the patients who lacked this chimeric product. Whereas three of the TEL/AML1 positive cases (3.0%) have relapsed to date, 27 patients without TEL/AML1 rearrangement (11.1%) suffered from relapse. To date, the only subset of B-lineage ALL with a favorable prognosis has been the hyperdiploid group (DNA index > or = 1.16 < 1.6). Our findings reinforce the need to include the molecular screening of the t(12;21) translocation within ongoing prospective ALL trials to prove definitively its prognostic impact.

Adolescent↗

PubMed1997

Diencephalic syndrome and disseminated juvenile pilocytic astrocytomas of the hypothalamic-optic chiasm region.

BACKGROUND: Diencephalic syndrome (DS) is a complex of signs and symptoms related to hypothalamic dysfunction; its main features are emaciation, despite a normal or slightly diminished caloric intake, and an alert appearance. DS has been almost exclusively described in association with space-occupying lesions of the hypothalamic-optic chiasm region, mainly juvenile pilocytic astrocytoma (JPA). A systematic diagnostic approach, including contrast-enhanced magnetic resonance imaging (MRI) of the child's head, is rapidly expanding our knowledge of this syndrome. METHODS: The MRI findings for three children affected by DS associated with biopsy-proven JPA, consecutively referred to the Pediatric Neuro-Oncology Program of the Department of Pediatrics at the University of Padua between September 1991 and January 1996, are presented in this article. The children were boys, ages 6, 7, and 18 months, respectively. RESULTS: In all three patients, the initial contrast-enhancing MRIs of the head showed evidence of tumor dissemination. This finding prompted a study of the spine, which in turn showed tumor deposits in all three subjects. Among the 43 patients younger than 16 years with low grade astroctyoma who consecutively entered the Neuro-Oncology Program during the study period, these 3 patients were the only ones who had disseminated tumors. CONCLUSIONS: In this study, the hypothesis was formulated that DS and disseminated hypothalamic-optic chiasm JPA tend to be more commonly associated than previously stated. This study suggests that the initial contrast-enhanced MRI of the head of a child affected by DS and hypothalamic JPA must be looked at carefully for evidence of tumor dissemination, and that the spine must also be examined if the findings are positive.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1997

Chronic myelomonocytic leukemia in childhood: a retrospective analysis of 110 cases. European Working Group on Myelodysplastic Syndromes in Childhood (EWOG-MDS)

Chronic myelomonocytic leukemia (CMML) is a rare hematopoietic malignancy of childhood. To define the clinical and hematologic characteristics of the disease, we performed a retrospective analysis of 110 children given the diagnosis CMML irrespective of karyotype. Median age at diagnosis was 1.8 years. Neurofibromatosis type 1 was known in 14% and other clinical abnormalities in 7% of the children. At presentation, the medium white blood count was 35 x 10(9)/L, with a median monocyte count of 7 x 10(9)/L. Karyotypic abnormalities in bone marrow cells were noted in 36% of the patients, whereas 26% of the children had monosomy 7. Children with monosomy 7 did not differ from those with normal karyotype with respect to their clinical presentation. However, they did display some characteristic hematologic features. Of 110 children, 38 received an allogeneic bone marrow transplant (BMT). The probability of survival at 10 years was 0.39 (standard error [SE] = 0.10) for the BMT group and 0.06 (SE = 0.4) for the 72 patients of the non-BMT group. Platelet count, age, and hemoglobin F at diagnosis were the main predicting factors for the length of survival in the non-BMT group. There is a strong need for a broad agreement on nomenclature in children with myelodysplastic syndromes (MDS). We propose here to use the French-American-British classification for MDS in childhood.

Bone Marrow Transplantation↗

PubMed1997

Expression and parental imprinting of the H19 gene in human rhabdomyosarcoma.

The expression of Insulin-like Growth Factor 2 (IGF-2) and H19, two genes located on human chromosome 11p15 and provided with cell growth modulating activity, is regulated by parental imprinting, in that the activity of their alleles is dependent on the parental origin. Parental bias in the genetic alterations of chromosome 11p15 observed in several pediatric cancers suggests the involvement of imprinted genes in tumor development. We have previously reported that the number of functional IGF-2 alleles is frequently increased in rhabdomyosarcoma (RMS), as a consequence of either relaxation of imprinting (LOI) or gene duplication. Here we show that the expression of the H19 gene is significantly suppressed with respect to normal muscle tissue in 13 out of 15 rhabdomyosarcomas with embryonal histology (ERMS) and in three out of 11 rhabdomyosarcomas classified as alveolar subtype (ARMS). Since a growth-inhibitory activity has been found associated with the H19 gene, the extinction of its expression can contribute to RMS development. Parental imprinting of the H19 gene was found conserved in all informative RMSs, including those whose ICF-2 imprinting was relaxed, indicating that LOI is a gene-specific event. Seven ERMSs and one ARMS displaying low H19 RNA levels showed an underrepresentation of the expressed allele in their genotype. This result is consistent with the paternal imprinting of the H19 gene and with the preferential loss of the maternal 11p15 alleles in these neoplasms. Low H19 expression was also found in four out of eight RMSs retaining the heterozygosity at 11p15, but showing IGF-2 LOI. These findings suggest that the genetic and epigenetic alterations affecting chromosome 11p15 in a high number of RMSs cause deregulation of more than one imprinted gene, possibly affecting tumor growth, including the extinction of H19 expression and an increase in the number of active IGF-2 alleles.

Alleles↗

PubMed1997

Spatial extinction on double asynchronous stimulation.

Despite the fact that visual extinction is widely considered a space-based disturbance of selective attention, there has been little theoretical consensus about the nature of its pathogenic mechanism. A specific disruption in the ability to disengage attention from ipsilesional stimuli, or a loss of weight with which contralesional objects compete for visual selection, have been hypothesized to account for the disorder. We tested the merits of these two explanations in a right-hemisphere-lesioned patient, FB, who failed to recognize a contralesional target only when it was shown concurrently to an ipsilesional target (i.e. visual extinction). His task was to report two target letters presented in rapid succession to the left and right of the fixation point. The order of stimulus presentation (Left-First vs Right-First), and the intertarget interval (stimulus onset asynchrony) were varied systematically. We showed that contralesional extinction may occur for successively presented targets, not just for stimuli displayed at the same time. Of most importance, FB was seriously and equally impaired in dealing with a contralesional stimulus when this either preceded the ipsilesional stimulus or followed it by an interval less than about 600 msec. The data appear to contradict the disengagement hypothesis, which predicted a substantial reduction of extinction when a stimulus was displayed first into the lesioned side of space. We suggest that a competitive model of visual selective attention fits the data quite well.

Aged↗