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V Orphanos

Publications and source records attributed to V Orphanos.

14 recordsLinked to original sources
PubMed1999

Apoptosis in patients with myelodysplastic syndromes: differential involvement of marrow cells in 'good' versus 'poor' prognosis patients and correlation with apoptosis-related genes.

Apoptosis has been implicated in the pathogenesis of marrow failure in MDS and the coexistence of marrow hypercellularity along with blood cytopenias was seen as evidence of extreme cell death of mainly mature cells in the marrow (ineffective hematopoiesis). We investigated apoptosis in 53 patients with MDS, by using single-step DNA extraction and gel electrophoresis and then by separating fresh marrow mononuclear cells in CD34+ and CD34- populations and in situ single cell evaluation of the process. We also studied the expression of apoptosis-related genes, in total and separated mononuclear marrow cells and correlated the findings with clinical and laboratory characteristics. Patients with apoptosis had increased marrow cellularity, longer overall survival and a longer period for transformation to AML. In 'good' prognosis MDS patients, total mononuclear marrow cells, as well as isolated populations of CD34+ and CD34- cells showed significant degrees of apoptosis; in 'poor' prognosis cases, however, apoptosis was evident only in a large percentage of CD34+ marrow cells and not in total or CD34- cells. Absence of expression of both c-myc and p53 in total marrow cells was associated with significant degrees of apoptosis and in isolated CD34+ and CD34- marrow cells the phenomenon was inversely correlated with the level of bcl-2 expression. In conclusion, marrow apoptosis is detected in both CD34+ and CD34- cells in early MDS and seems to be restricted to CD34+ cells in advanced MDS cases.

Aged↗
PubMed1999

Transcriptional map of chromosome region 6q16-->q21.

We present the transcription map of chromosome region 6q16-->q21 by mapping fifteen known genes within this region. Five genes lay in the subregion containing a tumor suppressor gene, eight genes are located in the subregion harboring a senescence gene, and two genes are distal to the latter region. The precise location of the genes was obtained using a previously described translocation and deletion mouse/human hybrid panel. An even more accurate definition was possible for the genes spanning the senescence gene region, since a previously described YAC contig with its restriction map was available. From this transcription map it is possible to derive a large region of synteny with mouse chromosome 10.

Animals↗
PubMed1997

Increased endothelin-1 content in the platelets of hemodialysed patients.

Patients undergoing hemodialysis, present platelets (PLTs) with physiological dysfunction. Aggregated PLTs stimulate endothelin-1 (ET-1) secretion from endothelial cells. In turn, ET-1 abolishes PLT aggregation. The aim of this study was to determine any presence of ET-1 in the PLTs of hemodialysed patients and to compare its levels with normal subjects. Platelets, isolated from hemodialysed patients, revealed lower aggregation (76 +/- 13%) compared with healthy subjects (96 +/- 2%). Plasma ET-1 was increased in hemodialysed patients 23.5 +/- 3.2 fmol/ml, vs. 10.9 +/- 1.6 fmol/ml in normal subjects. Immunoreactive endothelin-1 was detected in the platelets of both groups. The intraplatelet ET-1 of hemodialysed patients was 13.8 +/- 3.1 fmol/mg protein, vs. 7.9 +/- 1.3 fmol/mg protein in normal individuals. Total RNA was isolated from platelets and reverse transcriptase-mediated polymerase chain reaction (RT-PCR) revealed no presence of the preproET-1 mRNA in either normal or hemodialysed platelets. This suggests that ET-1 is internalized from the plasma. In summary, platelets contain but do not express ET-1. The increased levels of ET-1 in the platelets of the hemodialysed patients may be partly responsible for their lower aggregation.

Adult↗
PubMed1995

A radiation hybrid panel for human chromosome 6q.

A panel of 63 radiation-reduced hybrids has been derived from a mouse cell line containing a neo-marked human Chromosome (Chr) 6, primarily to provide a resource for higher resolution localization of new markers. Hybrids were generated with radiation doses of 40-400 Gy, selected in G418, and were shown by PCR to contain the neo gene. PCR was also used to score the retention of 15 loci that map from 6q13 to q25.2 of the current consensus map, plus six other loci assigned to 6q26-q27. An average retention frequency of 27.8% was observed, with the highest frequencies at D6S313 and D6S280 (63.5%) located near the centromere at 6q13, and at D6S283 (68.5%) at 6q16.3-q21, presumably close to the neo integration site. Lowest frequencies (4.8%) were observed for telomeric markers. All markers segregated independently except D6S297 and D6S193. Agreement and some improvement to the current consensus map of 6q was made by mapping 12 loci by the non-parametric statistical method of Falk. In addition, deletion mapping with informative hybrids allowed the ordering of six loci from 6q26 to q27 and permitted some integration of maps of this region.

Animals↗
PubMed1995

Allelic imbalance of chromosome 6q in ovarian tumours.

Previous work has implicated putative tumour-suppressor (ts) genes at 6q27 and a broad region at 6p12-q23. Here we report the results of a coded, randomised study of allelic imbalance at 12 loci on 6q on 40 pairs of coded tumour-blood pairs from patients with ovarian tumours. Our results provide clear evidence for the involvement of different regions of 6q in tumours of different histological subtypes. The involvement in serous tumours of a ts gene at the distal site is confirmed. However, proximal 6q presents a complex picture, with possibly three further ts genes: one at 6q21-23.3 involved at high frequency in benign and endometrioid tumours, another at 6q14-q15, also involved in endometrioid tumours, and a third suggested by a smallest region of deletion at 6q16.3-q21, between D6S275 and D6S300, that appears to be involved in early stage tumours. These observations point the way to a statistical study of the involvement of 6q in tumours of different histological type and staging performed on larger cohorts of samples.

Adenocarcinoma, Mucinous↗
PubMed1995

Proximal 6q, a region showing allele loss in primary breast cancer.

To define regions of deletion of chromosome 6q in breast cancer, we scored 18 (CA)n microsatellites for allelic imbalance (AI) in 42 paired blood/tumour samples. Heterozygosity frequencies of the markers in the sample population ranged from 31% to 92% (mean 68%). Two regions of the chromosome arm showed AI values greater than the background range of 10-22% (mean 17%) of informative cases that was observed with five markers spanning 6q21-q25.2. Firstly, seven markers gave AI values that averaged 35% in a region flanked by D6S313 (AI = 10%) at 6q13 and D6S283 (AI = 17%) at 6q16.3-21. The second region showed marginally increased AI at 6q25.2-q27 and included D6S193, previously shown to be close to a tumour-suppressor gene involved in ovarian carcinoma. Since AI of 6q in breast cancer was shown previously to be due predominantly to loss of heterozygosity, our results suggest the presence of at least two tumour-suppressor genes on 6q that are involved in breast cancer. The proximal region has not been recognised in breast cancer before and is involved in a higher frequency of tumours than the distal region.

Alleles↗
PubMed1994

Physical mapping of 43 STSs to human chromosome 6.

We have localized 43 sequence-tagged sites by deletion mapping using a chromosome 6 panel of 18 translocation hybrids. Thirty-four loci were mapped to the long arm of chromosome 6, and 9 were mapped to 6p. Many of the loci contain (CA)n dinucleotide repeated sequences and therefore will be useful markers for mapping genes on chromosome 6.

Alleles↗
PubMed1994

Deletion of a common region on the long arm of chromosome 6 in acute lymphoblastic leukaemia.

We have characterised a region of deletion on the long arm of chromosome 6 (6q) in six cases of acute lymphoblastic leukaemia, by fluorescence in situ hybridisation, using a series of YAC clones which map to 6q. Conventional cytogenetic analysis of four of these cases had been interpreted as showing terminal deletions of 6q. We demonstrated by FISH that in all cases the deletions were interstitial. D6S246 (6q16.3) was the only marker which was missing in all six cases, indicating a common region of deletion between the markers M6P1 at 6q14-15 and FYN at 6q21. Our results suggest the presence of a tumour suppressor gene within this interval.

Adolescent↗
PubMed1994

Common region of deletion on the long arm of chromosome 6 in non-Hodgkin's lymphoma and acute lymphoblastic leukaemia.

We have used fluorescence in situ hybridisation (FISH) with a series of yeast artificial chromosome (YAC) clones that map to the long arm of chromosome 6 (6q) to define the region(s) of deletion in seven cases of non-Hodgkin's lymphoma (NHL), in which a deletion of 6q had been detected by conventional cytogenetics. The FISH analysis detected two regions of deletion: (i) A proximal region flanked by M6P1 (6q14-15) and FYN (6q21), containing D6S246, which was missing in all seven cases. This locus was also found to be deleted in all six cases of acute lymphoblastic leukaemia (ALL) studied previously. (ii) A second region of 6q, which was distal to 6q23.1 (D6S238) and included ESR (6q25.1) and D6S281 (6q27), which was shown to be present in all our cases of ALL, was found to be deleted in 4 of the 7 cases of NHL. Our results support the suggestion that tumour suppressor genes, involved in the pathogenesis of lymphoid malignancies, may be present within these regions.

Adult↗
PubMed1994

Glomerular expression and cell origin of transforming growth factor-beta 1 in anti-glomerular basement membrane disease.

The glomerular expression (mRNA levels) of transforming growth factor-beta 1 (TGF-beta 1) was assessed in two forms of rat anti-glomerular basement membrane (GBM) disease, a macrophage-independent and a macrophage-dependent variant. After a single intravenous injection of rabbit anti-rat GBM immune serum, significant proteinuria and histopathologic changes developed in both variants. Increased TGF-beta 1 mRNA levels were found in isolated glomeruli of the macrophage-dependent variant only in which glomerular infiltration by macrophages also occurred. Macrophages isolated from glomeruli of animals with this variant demonstrated TGF-beta 1 mRNA levels comparable to those found in glomeruli isolated at the same time point after injection of the anti-GBM serum. The observations indicate that in anti-GBM disease, enhanced glomerular TGF-beta 1 expression occurs in the macrophage-dependent variant and suggest that infiltrating macrophages account for this event.

Animals↗
PubMed1993

Detection of gene rearrangements in reactive lymphoid processes.

We report the immunohistologic and the genotypic analysis of lymph node biopsies from 23 cases of reactive processes, and two cases of atypical lymphoproliferations (AL). Clonal gene rearrangements were detected in 5 cases of proven reactive processes as well as in both AL, in which no signs of malignancy were detected during the phenotypic analysis. No patient, apart from the two AL cases, showed any progression to malignancy during a follow-up period of 28-43 months after the initial biopsy.

Antigens, CD↗
PubMedDate not supplied

Cytokine gene expression in the marrow stromal cells of patients with giant cell arteritis.

OBJECTIVE: Anemia of chronic disease is a common feature of giant cell arteritis (GCA). It has been shown that constitutive hematopoiesis is regulated in the bone marrow microenvironment by direct cell-to-cell contact between hematopoietic progenitor cells and marrow stromal cells. Since cytokines are of crucial significance in this process, we decided to examine the role of stem cell factor (SCF), granulocyte macrophage colony stimulating factor (GM-CSF), interleukin 3 (IL-3), granulocyte colony stimulating factor (G-CSF), and interleukin 1 alpha (IL-1 alpha), known for their stimulatory effects on in vitro hematopoiesis; and transforming growth factor beta (TGF beta), interferon gamma (IFN gamma) and tumor necrosis factor alpha (TNF-alpha), known for their inhibitory effect, in the anemia of GCA. METHODS: The expression of these cytokines was examined in the marrow stromal cells from 6 GCA patients with anemia of chronic disease and in 6 healthy individuals by the reverse transcription mediated polymerase chain reaction (RT-PCR). RESULTS: Consistent constitutive gene expression was detected in the marrow stromal cells of all control samples for SCF, GM-CSF, IL-1 alpha, TGF beta and TNF-alpha, while only 2/6 expressed IFN gamma. None of the controls expressed either IL-3 or G-CSF. In all GCA patients SCF, TGF beta and TNF-alpha were expressed, but the level of expression was reduced compared to the control group. IL-1 alpha was expressed in 3/6 patients, and IFN gamma in 2/6. More importantly, GM-CSF expression was not detected in any patient, in marked contrast with the controls. CONCLUSION: The combination of the defective expression of SCF and GM-CSF, cytokines with a known stimulatory effect on in vitro hematopoiesis, may contribute to the pathogenesis of anemia in GCA.

Anemia↗