Publications by authors named "Karelis Urdaneta"

8 Publications

  • Page 1 of 1

[Utility of chromosome banding with ALU I enzyme for identifying methylated areas in breast cancer].

Invest Clin 2012 Dec;53(4):331-41

Instituto de Investigaciones Genéticas, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Cancer is a group of disorders characterized by uncontrolled cell growth which is produced by two successive events: increased cell proliferation (tumor or neoplasia) and the invasive capacity of these cells (metastasis). DNA methylation is an epigenetic process which has been involved as an important pathogenic factor of cancer. DNA methylation participates in the regulation of gene expression, directly, by preventing the union of transcription factors, and indirectly, by promoting the "closed" structure of the chromatine. The objectives of this study were to identify hypermethyled chromosomal regions through the use of restriction Alu I endonuclease, and to relate cytogenetically these regions with tumor suppressive gene loci. Sixty peripheral blood samples of females with breast cancer were analyzed. Cell cultures were performed and cytogenetic spreads, previously digested with Alu I enzyme, were stained with Giemsa. Chromosomal centromeric and not centromeric regions were stained in 37% of cases. About 96% of stained hypermethyled chromosomal regions (1q, 2q, 6q) were linked with methylated genes associated with breast cancer. In addition, centromeric regions in chromosomes 3, 4, 8, 13, 14, 15 and 17, usually unstained, were found positive to digestion with Alu I enzime and Giemsa staining. We suggest the importance of this technique for the global visualization of the genome which can find methylated genes related to breast cancer, and thus lead to a specific therapy, and therefore a better therapeutic response.
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December 2012

Trisomy 19 and t(9;22) in a patient with acute basophilic leukemia.

Case Rep Pathol 2011 13;2011:269491. Epub 2011 Sep 13.

Genetic Medical Unity, Faculty of Medicine, University of Zulia, Maracaibo, Venezuela.

We report a case of acute basophilic leukemia with two coexisting clonal abnormalities, t(9;22) and trisomy 19. The blast showed positive reaction with myeloperoxidase but negative reaction with chloroacetate esterase and acid phosphatase. Metachromatic features of the blast were observed with toluidine blue stain. Ultrastructure study showed the presence of azurophilic granules in basophils and blast mast cells. Conventional and molecular cytogenetic studies revealed, t(9;22) with BCR/ABL positive and trisomy 19 in all metaphase cells. To our knowledge, this paper here is the first to present acute basophilic leukemia with trisomy 19 and t(9;22).
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http://dx.doi.org/10.1155/2011/269491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3420414PMC
August 2012

Petty-Laxova-Wiedemann progeroid syndrome: further phenotypical delineation and confirmation of a rare syndrome of premature aging.

Am J Med Genet A 2009 Oct;149A(10):2200-5

Medical Genetics Unit, Faculty of Medicine, University of Zulia, Zulia, Bolivarian Republic of Venezuela.

A 10-year-old boy with manifestations of Petty-Laxova-Wiedemann progeroid syndrome (PLWPS), a rare neonatal progeroid condition, is described and compared with those previously reported. Clinical manifestation include: severe pre- and postnatal growth retardation, "progeroid" face, large open fontanelle in infancy, umbilical hernia at birth, pseudomacrocephaly, wide calvaria, sparse scalp hair, markedly diminished subcutaneous fat, scoliosis, partial cutaneous syndactyly, aplastic and hypoplastic distal phalanges with aplasia and hypoplasia of nails, undescended testes, and normal cognitive and motor development. This appears to be one of only a handful of cases of PLWPS reported in an older child or adult.
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http://dx.doi.org/10.1002/ajmg.a.32884DOI Listing
October 2009

[Frequency and clinicopathological associations of K-ras mutations in Venezuelan patients with colo-rectal cancer].

Invest Clin 2009 Mar;50(1):55-63

Universidad Centro Occidental Lisandro Alvarado, Barquisimeto, Venezuela.

Mutations in the K-ras oncogene are common in colo-rectal cancer, which affect the biological behaviour and may influence the susceptibility to therapy in these tumors. The objective of this work was to identify the types of K-ras mutations observed in referred patients with colo-rectal cancer and to relate them to their degree of histological differentiation and clinical stage. Histopathological and clinical data were obtained from medical records. DNA was obtained from both, fresh tissue and tumor tissue embedded in paraffin. The K-ras gene was amplified through the polymerase chain reaction (PCR) and the amplified fragments were digested with restriction enzymes. We found mutations in codons 12 and 13 of the K-ras oncogene in 23.33% of patients. Of these, 28.57% were located at codon 12, 57.14% were at codon 13 and 14.29% at both codons. They were more frequent in tumors located in the left hemicolon and, according to their histological type, were more frequent in well differentiated adenocarcinomas (58.70%) and in mucinous (28.57%). The identified mutations were more frequent in advanced stages (C2) of Dukes' classification. The molecular analysis of the K-ras oncogene made mutations evident, which could be useful in the diagnosis and prognosis of colorectal tumors. The frequency of mutations found in this work is similar to some of those reported worldwide; however, they differ in the more frequent type of mutation, which, in our study, was located at codon 13 in more than 50% of the cases.
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March 2009

Prospective prenatal serum screening for Down syndrome in Venezuela.

Int J Gynaecol Obstet 2008 Dec 25;103(3):241-5. Epub 2008 Sep 25.

Unidad de Genética Médica, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Objective: To assess the usefulness of triple-marker screening for Down syndrome in Venezuela.

Method: Maternal serum concentrations of alpha fetoprotein (AFP), beta human chorionic gonadotropin (beta-hCG), and unconjugated estriol (uE3) were measured weekly in 3895 women from the 15th to the 20th week of pregnancy. Population-specific likelihood ratios were determined and used to calculate the risk of fetal Down syndrome for each pregnancy.

Results: The median multiple of the median values for AFP, beta-hCG, and uE3 concentrations were 0.69, 2.10, and 0.67 for the affected pregnancies. The likelihood ratio for a positive result was 1:19. The detection and false-positive rates were 69.23% and 5.8%.

Conclusion: These findings were consistent with reported data and therefore confirmed triple-marker serum screening as effective and suitable for prenatal care in Venezuela. Latin American governments and Health Agencies should recommend offering this screening method to all pregnant women.
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http://dx.doi.org/10.1016/j.ijgo.2008.07.017DOI Listing
December 2008

[Relationship of oncogene C-erbB-2 amplification in breast cancer with pathological parameters and disease free survival].

Rev Med Chil 2005 Feb 7;133(2):151-7. Epub 2005 Apr 7.

Unidad de Genética Médica, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Background: Proto-oncogene c-erbB-2 is located in chromosome 17 region q21 and codifies a 185 Kd protein, with tyrosine kinase activity. The amplification of this gene is associated with relapse and lower survival in breast cancer. Overexpression of this gene can be detected by immunohistochemistry (IHC). However, fluorescence in situ hybridization (FISH) and chromogenic in situ hybridization (CISH) allow the simultaneous analysis of morphology and overexpression of the gene.

Aim: To evaluate the relationship of c-erbB-2 oncogene amplification measured by FISH with histological graduation, presence of positive Iymph nodes and evolution of breast cancer.

Patients And Methods: One hundred and ten tissue samples of invasive ductal or lobulillar breast cancer, positive for c-erbB-2 oncogene by IHC were analysed. The presence of c-erbB-2 oncogene amplification was subsequently analyzed by FISH.

Results: There was a significant association of c-erbB-2 amplification by FISH with pathological graduation of the tumor, number of regional Iymph nodes involved and disease free survival.

Conclusions: Proto-oncogene c-erbB-2 amplification is a good indicator of bad prognosis in invasive breast cancer.
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http://dx.doi.org/10.4067/s0034-98872005000200001DOI Listing
February 2005

[Chromosome anomalies in Venezuelan patients with multiple myeloma].

Invest Clin 2003 Dec;44(4):327-35

Escuela de Bioanálisis, Unidad de Genética Médica, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

The cytogenetic study is an important prognostic factor in Multiple Myeloma (MM). The chromosomal analysis has demonstrated to be essential for the genetic advise in relation to the diagnosis, prognosis and might suggest precociously, the most appropriate treatment for the majority of hematological malignancies. The objective of this investigation was to identify the chromosomal abnormalities in samples of bone marrow (BM) from patients with diagnosis of MM. The chromosomal studies were carried out in BM cultures, following the technique described by Yunis. Without exception the analysis was carried out previous to any treatment with cytostatics. Twenty two samples of BM were received for chromosomal studies in the Unit of Medical Genetics of the University of the Zulia (UGM-LUZ). In 19 out of 22 samples (86%) appropriate material was obtained by cytogenetic analysis; 6 (32%) showed normal karyotype and 13 (68%) presented numeric and structural chromosomal abnormalities. Eight (62%) of the chromosomal anomalies detected were numerics, three cases (38%) with hyperdiploidy involving chromosomes 3, 5, 7, 15, 17, 18, 19 and four cases (50%) with hypodiploidy involving the chromosomes 8, 16, 17, 18, X and Y. Triploidy was found in one case (12%). Structural abnormalities were present in 4 cases (31%) such as deletions 5p11, 11p14, 14q32, 17p11 and 1 case (7%) presented structural and numeric anomalies. This study shows that the majority of patients with multiple myeloma have several chromosomal abnormalities with some differences from other reports.
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December 2003

[Clonal chromosomal anomalies in colorectal tumors].

Invest Clin 2002 Dec;43(4):263-70

Unidad de Genética Médica, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Colorectal tumors constitute a reason of frequent consultation in gastroenterology services in the world. They constitute the second cause of mortality in the world and the fourth cause of mortality for cancer in Venezuela. It usually begins as a polyp that becomes malignant due to a mutation at the level of the genetic code that controls the growth and the repair of cells. The present work reports the clonal chromosomal abnormalities observed in 15 samples from benign tumors as well as malignant colorectal tumors and to relate these findings. There were clonal chromosomal anomalies in 11/15 (73.33%), 4 corresponded to carcinomas and 7 to adenomatous polyps. In 7/11 (63.6%) there were anomalies of the monosomy type in the chromosomes 8 and 22, other anomalies corresponded to trisomy of the chromosomes 11 and 18, and a single case with a structural anomaly that corresponded to a del(17p). The chromosomal anomalies in adenomatous polyposis have been related with the beginning of malignant disease and, in the case of carcinomas, it has been related with progression of the illness toward metastasis and death. The use of this tool could be used as a prognostic factor for patients with non familial adenomatous polyposis.
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December 2002