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M Robledo

Publications and source records attributed to M Robledo.

At least 55 records · Page 3Linked to original sources
PubMed1995

Somatic stability in chorionic villi samples and other Huntington fetal tissues.

We have studied different tissues from two affected fetuses with Huntington's disease (HD). In the first case the analysis was performed at 11 weeks of pregnancy; CAG repeats from seven different tissues were compared with the results obtained in the chorionic villi sample (CVS). We found 42 CAG repeats in all samples. In the second case the study was done at 12 weeks; eight tissues (including brain) were studied and compared with the CVS; in all of them, 44 CAG repeats were obtained. Our results show a somatic stability in the different analyzed tissues and suggest that mitotic instability can be a secondary consequence of neuronal degeneration and gliosis. Likewise, our data show great viability in the prenatal diagnosis (PD) of Huntington's disease using samples from any tissue.

Abortion, Therapeutic↗
PubMed1995

[Large-cell anaplastic lymphomas: a genetic and immunophenotypic study].

PURPOSE: To characterize from a genetic point of view a group of non-Hodgkin's anaplastic large-cell lymphomas (ALCL) by Southern blot and PCR methods with different probes (molecular study) and with direct or post 24-78 hours cultures with GTC banding techniques (cytogenetic). To correlate the results to the immunophenotype performed with a complete panel of monoclonal antibodies (MoAb) according to avidin-biotine and alkaline phosphatase (APAAP) methods. MATERIAL AND METHODS: Sixty cases of ALCL were reviewed and only 19 selected (with frozen or fresh material) because a complete immunohistologic and genotypic correlation had been done. According to CD15 expression two groups were considered, CD15+ (the so-called Hodgkin's related or Hodgkin's like) and CD15- or classical type. RESULTS: Only 26.5% of cases showed immuno -genotypic correlation. Immunohistochemistry is an accurate method for activation, proliferation and B-cell nature, but T-cell cases were not stained because T-cell paraffin markers are not completely specific. CD15 group had only 30% rearranged cases with scarce cytogenetic abnormalities, as it occurs in Hodgkin's disease (HD). ALCL classical type showed 66% rearranged cases, and one of the T-cell cases showed an incomplete t (2:5) translocation or polyploid cell lines. CONCLUSIONS: Both groups have different genetic and immunophenotypic behaviour which resembles HD or NHL. CD15 positive cases or ALCL HD-related constitute a borderline entity which has to be recognized because of the different therapy and clinical behaviour.

Hodgkin Disease↗
PubMed1995

[Characterization of mutation of the P53 gene in lymphomas].

PURPOSE: To analyze P53 mutations in a series of NHL and to determine its implication in the inactivation of the tumor suppressor function. MATERIAL AND METHODS: We analyzed 18 lymphomas by SSCP (exons 5 to 9) and subsequent sequencing technics to detect and characterize mutations on this gene. Loss of heterozigosity (LOH) was also studied with a VNTR near the p53 gene and with a intragenic microsatellite, comparing tumor and normal tissue. RESULTS: We found altered bands by SSCP in 5 cases, 4 of them have been described by sequencing analysis. One case was a polymorphism and the others were missense mutations. All mutations appeared in high grade lymphomas. Only one case showed LOH in both VNTR and microsatellite. CONCLUSIONS: This results suggest that p53 mutations may be associated with more malignant lymphomas.

Base Sequence↗
PubMed1995

Genetic instability of microsatellites in hematological neoplasms.

Genetic instability has been recently related to point mutations on genes involved in DNA repair pathway of errors produced during replication. These molecular alterations have been described in hereditary and sporadic colon carcinomas and related tumors. To examine genetic instability on lympho- and myeloproliferative processes, we analyzed the behaviour of 10 microsatellite markers and one VNTR on different chromosomes in 10 patients with non-Hodgkin lymphomas (NHL), one patient with acute lymphoblastic leukemia (ALL) and 10 patients with acute myeloid leukemia (AML). Mobility shifts were found in three of those cases. One of them showed genetic instability for several markers--microsatellites and VNTR- and the other two showed differences for only one marker. As a correlation between point mutations in MSH2 gene and the presence of genetic instability in hereditary non-polyposis colon cancer (HNPCC) and related tumors has been found, we analyzed the sequence of a conversed region of this gene in the cases showing this phenomenon. We only found a polymorphism, previously described, in 669 codon from cDNA.

Burkitt Lymphoma↗
PubMed1995

Polymorphic variations in peripherin-RDS gene in the Spanish population.

The authors report a study of polymorphisms in the peripherin-RDS gene in 21 Spanish families affected with Autosomal Dominant Retinitis Pigmentosa and 56 unrelated normal individuals. We found 3 variants in first exon and nine variants in the third exon in an SSCP analysis, all corresponding to different previously described polymorphisms.

Base Sequence↗
PubMed1995

[T-cell-rich B-cell lymphoma: multifactorial study of 4 cases].

PURPOSE: With the correlational study of four cases in several areas (clinic, morphoimmunologycal, ultrastructural and genetic) we try to valorate the still controversial entity known as T-cell rich B-cell lymphoma (TRBL), and stablish some useful clues in order to settle down the differential diagnosis between TRBL, Hodgkin's disease (HD), and T-cell non-Hodgkin's lymphomas (TNHL). PATIENTS AND METHODS: Cases proceeded from Oncology Department, and had been firstly misdiagnosed either as HD (3 cases) or as TNHL (1 case). Biopsies were processed and stained in routine way, H&E, Giemsa and Wilder. Immunohystological study, using monoclonal antibodies against B-cells, T-cells, histiocytes, activation and proliferation markers, was also performed with avidin biotine peroxidase (ABC) method. Ultrastructural study was performed in three of the cases; two patients were studied by PCR and Southern blot. RESULTS: All of the cases showed a diffuse hystological pattern, with variable fibrosis, and proliferation of venules and capillaries. Small lymphoid cells, being positive for CD3, were dominant. Large blastic cells, positive for CD20, some of them with a Sternberg-like appearance, could be found, in a spitty pattern. Histiocytes were abundant and positive to CD68. Proliferation index (Ki-67) ranged between 13 and 24.5% being the stain mainly positive for B-cells and in a certain extent, also for T-cells. Ultrastructural features were closer to those of the NHL than to the ones found in HD. Molecular study failed to prove any rearrangement. CONCLUSIONS: TRBL is a rare entity between B-cell NHL group. Diagnosis and differential diagnosis (mostly with HD and T-cell NHL) have to be properly made, because of the very distinct prognosis and therapy.

Adult↗
PubMed1994

Trinucleotide (CAG) repeat expansion in chromosomes of Spanish patients with Huntington's disease.

Huntington's disease (HD) is a neurodegenerative and hereditary disease characterized by progressive movement disorders and mental and behavioral abnormalities. The HD gene is an expanding and unstable trinucleotide repeat (CAG repeat sequences). We studied 77 individuals from 38 families with HD in an attempt to obtain information for genetic counselling and differential diagnosis. Our results indicate that individuals with more than 40 repeats will be affected by the disease, whereas those with fewer than 30 will be healthy. There can be some overlap between 30 and 40 repeats, and one should be careful when interpreting these results.

Adolescent↗
PubMed1994

DNA content in non-Hodgkin's lymphoma. Comparison between flow cytometry and cytogenetics in fresh and paraffin-embedded tissue.

DNA content of 36-non-Hodgkin's lymphomas was analyzed by flow cytometry (FCM) and cytogenetics (CG), 21 in fresh and 15 in paraffin-embedded tissue. The results of both techniques were coincident in 60% of the fresh tissue samples and in 45% of the paraffin-embedded ones, the reason for this difference could be the poor resolution of DNA histograms from paraffin-embedded tissue. All samples judged as aneuploid by FCM were aneuploid also by CG. Some samples with a hyperdiploid population by CG gave a diploid population by FCM with a 'false' high DNA-synthesis (S) fraction. From a technical point of view, CG and FCM have to be performed on the same fresh tissue.

Cell Cycle↗
PubMed1994

[The gene responsible for Huntington's disease in Spanish families: its diagnostic value and the relation between trinucleotide expansion and the clinical characteristics].

We have studied 77 patients from 38 families with Huntington's disease (HD) analyzing the genes trinucleotide repeats (CAG)n; we have compared the results with those of 154 chromosomes from control population. Patients with HD range from 39 to 70 repeats while healthy patients have between 12 and 36 repeats. These results show the great feasibility of this genetic test. We do not have found a correlation between expansion's repeats and age of onset except for young people with the disease; in these cases we have found high level of expansions (more than 65) that could be a prognostic parameter of the disease.

Adolescent↗
PubMed1994

[Detection of monoclonality in non-Hodgkin's B-cell lymphomas using PCR].

PURPOSE: To evaluate the reliability of a PCR technique for the detection of monoclonal B-cell non-Hodgkin's lymphoma (NHL) in a group of patients previously showing monoclonal gene rearrangement with Southern Blot techniques. PATIENTS AND METHODS: A group of 22 cases of NHL were studied with immunocytochemical techniques by means of a complete monoclonal antibody panel after previous demonstration of monoclonal rearrangement with the JH probe. Specific Fr2 and Fr3 priming of the variable regions of the IgH genes was used. One positive and two negative controls were used on each PCR test. RESULTS: Monoclonal lymphoma was detected in 18 cases (82%), seven of them with Fr2 and Fr3, whereas five cases had Fr2 and the remainders had only Fr3. CONCLUSION: PCR seems a good alternative for detecting monoclonal lymphoproliferative syndromes instead of Southern Blot due to both its specificity and high sensitivity. The hypotheses to explain false negative results are discussed.

Antibodies, Monoclonal↗
PubMed1992

Correlation between cytogenetic and molecular analysis of t(14;18) in follicular lymphomas.

A comparison between cytogenetic and molecular results of t(14;18) has been performed in 12 patients with follicular lymphomas: five nodular and seven diffuse. Ten cases showed cytogenetic alterations with different markers, including a 14q+ in eight: in four it was the result of a t(14;18). Molecular analysis by Southern blotting with bcl2 probes from major and minor cluster regions, and PCR with primers from major and minor regions showed differences versus the cytogenetic results. The correlation found between cytogenetic and molecular results suggests other factors, such as geographical differences or different pathogenetic mechanisms, more than methodologic aspects, to explain the different frequencies of this marker among countries.

Adult↗
PubMed1992

A multiparametric study of malignant lymphoma of mucosa associated lymphoid tissue (MALT).

A morphological, immunophenotypic and ultrastructural study, cell cycle estimation, DNA and cytogenetic analysis were performed in ten cases of B-MALT lymphomas. Five had low grade lymphoma and five had high grade. Low and high grade cases showed the same cells but in different percentages: These included centrocyte-like cells with occasional monocytoid cytoplasmic changes, and centroblast-like cells. However, in high grade cases more dysplastic and large cells were present. All cellular types showed an important development of rough endoplasmic reticulum. In all cases a large panel of monoclonal antibodies was employed to study the B-cell immunophenotype. Ki-67 positivity ranged from 5% to 30% in low-grade cases and from 50% to 70% in high-grade cases. Gene rearrangement analysis showed rearrangement with Jh probe and half of the cases were also rearranged with the Kde probe (Kappa constant chain gene). A rearrangement banding pattern with TCR genes was not present in any of the cases. Cytogenetic study showed complex alterations in high grade cases and a normal karyotype in low grade lymphomas. Only one case had rearrangement for the bcl-2 probe.

Female↗
PubMed1991

[Cytogenetic and molecular aspects in MALT lymphomas].

Cytogenetic and molecular results in 10 patients with extranodal lymphoma (MALT): 5 low grade and 5 high grade, were compared with the results observed in nodal lymphomas. This study suggests that there are cytogenetic differences between extranodal and nodal low grade lymphomas. Both molecular analysis by conventional Southern blot with probes for the major and minor regions of bcl-2 gene, and PCR analysis with primers from these regions, showed that t (14; 18) is a sporadic event in MALT lymphomas.

Aneuploidy↗
PubMed1991

[Molecular analysis in 23 patients with T-lymphomas].

Gene rearrangement analysis has been performed in 23 patients with T-cell lymphoproliferative diseases: 4 cases with T-gamma lymphocytosis, one case of a Sezary's syndrome, one case of T-cell angioimmunoblastic lymphoma, two cases of T-cell lymphoepitheloid lymphoma, 11 patients with T-cell pleomorphic lymphoma, 3 cases of large anaplastic T-cell lymphoma and one case of T-cell lymphoblastic lymphoma. Rearranged banding patterns have been observed for at least one of the T-cell receptors (TCR) in 19 of the cases, and germ line configuration of the TCR and Ig genes in the other four. Likewise, both Ig and TCR rearrangements have been observed in three cases (one case of T-cell pleomorphic lymphoma, one case of large anaplastic T-cell lymphoma and one case of T-cell lymphoblastic lymphoma). Molecular genetic techniques have been used in order to direct monoclonal proliferations of T cell in the tumoral tissues, to determine the T- or B-cell lineage of the neoplasia and also to outline the molecular characteristics of each group that constitutes the complex classification of T-cell malignancies.

Gene Rearrangement, B-Lymphocyte↗