CHROMOSOME ABNORMALITIES IN MULTIPLE MYELOMA.
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OBJECTIVE: To analyze variables affecting couples' decision making about prenatal cytogenetic diagnosis in patients with no access to legal termination of pregnancy (TOP). METHODS: Patients undergoing invasive prenatal diagnosis were anonymously surveyed after counseling and before the procedure. The questionnaire enquired about sociodemographic features, medical history, knowledge of and attitudes toward genetic testing and TOP. RESULTS: Two genetic units distributed 372 questionnaires. Mean maternal age was 36 +/- 4 years. Access to prenatal genetic counseling was mainly patient's own initiative, or 'self-referral'. Most self-referred patients (87%) considered that 'receiving accurate information' was the main issue. Eighty-one per cent of all couples knew that TOP because of fetal anomalies was not legal. In case of a serious anomaly, 68.2% of patients would contemplate TOP, in spite of the risk of being exposed to an unsafe abortion. CONCLUSIONS: In many countries, prenatal genetic testing is offered, but TOP is not available. In the present study, although most of the couples who decided to undergo prenatal genetic testing were aware of this, they still chose to perform prenatal diagnosis. The main reason given was to obtain reliable information about fetal condition. Finally, if a fetal chromosomal abnormality were detected, most of them would consider TOP.
Tumor specific chromosomal abnormalities have been identified in several histologic subtypes of benign and malignant bone tumors. These anomalies have proven to be useful diagnostically. Characterization of recurrent chromosomal abnormalities also has provided direction for molecular investigations of pathogenetically important genes. Cytogenetic reports of chondroblastoma, a rare benign bone tumor, are few. Cytogenetic analysis of a benign and a malignant chondroblastoma in this study revealed the following abnormal chromosomal complements: 47,XY,+5,t(5;5)(p10;q10) and 45, XY,del(2)(p23),del(3)(q23q27),dup(8)(q12q21.), del(11) (q14q23), -13, add (17) (q25) x 2, respectively. Although a specific chromosomal abnormality has not yet emerged for chondroblastoma, abnormalities of chromosomes 5 and 8 have been reported previously in this neoplasm, suggesting preferential involvement of these two chromosomes.
Resistance to the lethal effects of ionizing radiation has been demonstrated in a wide variety of cell types with defects in the p53 gene (thymocytes, splenic B and T cells, in vitro hemopoietic colony-forming cells and intestinal cells of the mouse, embryo cells of the rat, and human Burkitt's lymphoma cells). In contrast, Slichenmeyer et al. (Cancer Res. 53, 4164-4167, 1993) found no evidence of resistance in fibroblasts derived from p53 null mice. The aim of our study was to compare the radiation response of hemopoietic colony-forming cells (in vitro CFC) and of fibroblastoid colony-forming cells or units (CFU-F) within the same tissue (marrow) in p53 null mice (-/-), heterozygotes (+/-) and wild-type animals (+/+). We have also tested the hypothesis that, in proliferating cells, radiation-induced cell killing is mediated through chromosome damage by examining the relationship between these end points in hemopoietic cells of the three mouse types. Both in vitro CFC and CFU-F of -/- mice were resistant to cell killing compared with +/+ and +/- mice whose cellular sensitivities were indistinguishable. The resistance was characterized by a broader "shoulder" on the cell survival curve, i.e. a higher extrapolation number but similar D0 values using the multitarget model or a lower alpha coefficient using the linear-quadratic model. The frequency of chromosomally abnormal marrow cells after irradiation was similar for the three genotypes. However, marrow cells with aberrations carried more aberrations in -/- mice than in +/+ or +/- mice such that the total number of aberrations per 100 cells was higher in -/- mice. Since there were no differences in the yields of aberrations between genotypes in spleen lymphocytes or in CFU-F (both noncycling at the time of irradiation) and less mitotic inhibition in -/- marrow cells than in +/+ or +/- cells, the chromosomal radiosensitivity of -/- marrow hemopoietic cells might be related to reduced cell cycle delay allowing insufficient time for repair, but other explanations have been considered. We postulate that the radiation resistance of both hemopoietic CFC and CFU-F in -/- mice is a consequence of the failure of DNA/chromosome damage to trigger apoptosis or permanent cell cycle arrest to the same extent as in the +/+ or +/- mice: hence the lack of correlation between chromosome damage and cell death in the three mouse types.
Recent studies suggest that leptin, the product of the obese gene, is produced by the placenta during pregnancy. The present study addressed the question whether second trimester maternal serum leptin could be altered by fetal Down syndrome or Edwards syndrome. Maternal serum leptin concentrations were measured in 18 pregnancies complicated with Down syndrome, six pregnancies complicated with Edwards syndrome and 183 uncomplicated pregnancies during the second trimester of pregnancy. The present results demonstrate that leptin concentrations in uncomplicated pregnancies slightly decrease from the 16th week of pregnancy, reaching a minimum of 18.8 ng/ml around the 20th week, and then rapidly increase to 28.2 ng/ml by the 24th week. Leptin correlation with maternal body weight decreases from r=0.695 at 16-17 week of gestation to r=0.544 at >22 weeks of gestation. There was no significant difference between the mean MoMs of Down syndrome- (0.926) or Edwards syndrome- (0.960) affected pregnancies and normal pregnancies (1.002). A weak correlation (r=0.18, p<0.02) was observed between corrected leptin MoMs and human chorionic gonadotrophin (hCG) MoMs in normal pregnancies. It is assumed that around the 20th week of pregnancy placental leptin production is activated or at least is accelerated and it is added to the amount of leptin produced by maternal adipose tissue. Fetal Down syndrome or Edwards syndrome does not seem to alter maternal leptin concentration and therefore leptin cannot be used as a marker for these chromosomal abnormalities in the early second trimester of pregnancy.
Myelodysplastic syndrome (MDS) is believed to be a stem-cell disorder involving cytopenia and dysplastic changes in three hematopoietic lineages. However, the involvement of pluripotent stem cells and progenitor cells has not been clarified conclusively. To address this issue, we used fluorescence in situ hybridization (FISH) of blood and bone marrow (BM) smears for mature cells and FISH of cells sorted by fluorescence-activated cell sorting for progenitor cells. Seven patients with MDS associated with trisomy 8 were studied. FISH showed +8 in granulocytes, monocytes, and erythroblasts, but not in lymphocytes. Sorted cells of T (CD3(+)), B (CD19(+)), and NK cells (CD3(-)CD56(+)) from peripheral blood did not contain +8, nor did CD34(+) subpopulations from BM including B (CD34(+)CD19(+)), T/NK (CD34(+)CD7(+)) progenitors, and pluripotent stem cells (CD34(+)Thy1(+)). The +8 chromosome abnormality was identified in stem cells only at the level of colony-forming unit of granulocyte-erythrocyte-macrophage-megakaryocyte (CFU-GEMM; CD34(+)CD33(+)). It may thus be concluded that cells affected by trisomy 8 in the context of MDS are at the CFU-GEMM level and that cells of lymphoid lineage are not involved. These results provide new insights into the biology of MDS and suggest that intensive chemotherapy and autologous BM transplantation may become important therapeutic strategies.
The karyotype of nine of 11 Wilms' tumors was successfully analyzed using chromosome banding techniques. Peripheral lymphocytes had a normal karyotype in all six analyzed cases. Cultured cells from one tumor had a normal karyotype; however, they appeared to be fibroblasts. A chromosome 11 deletion, del(11)(p13p14), similar to that seen in patients with sporadic aniridia, was found as the sole abnormality in cells from one tumor. Abnormalities of chromosome 1 resulting in trisomy for the long arm (q21-q31) were found in five cases. Two of them had a translocation involving 1q and 16q, although the breakpoints in each chromosome appeared to differ in the two cases. Two patients had an isochromosome of the long arm, i(1q), and a fifth case had a duplication of the long arm as a result of karyotypic evolution. Chromosome 16 abnormalities were found in three cases, resulting in the partial monosomy of the long arm, sharing q22 as a common deletion. The same three cases also had trisomy 1q due to an unbalanced translocation of 1q or an i(1q). Trisomy for both chromosomes 9 and 12 were present in three cases. Two patients each had whole or partial trisomy of chromosomes 6, 7, 8, 17, and 18. Our data show that although an 11p deletion can occur as a mutation confined to tumor cells, the most common changes are trisomy for 1q, and less often a deletion of 16q.
The purpose of this study was to determine whether continuing experience in prenatal diagnosis of conotruncal malformations (CTMs) has resulted in improved diagnostic accuracy and outcome. Previous reports have demonstrated particular difficulty with ascertainment of the spatial relationship of the great arteries in patients with CTM. The prognosis for fetuses with CTM was poor. Medical records of 113 consecutive fetuses in whom a CTM (tetralogy of Fallot [TOF], double-outlet right ventricle [DORV], type B aortic arch interruption, transposition of the great arteries [TGA], and persistent truncus arteriosus [TA]) was diagnosed antenatally between 1994 and 2003 were reviewed. The diagnosis of the 91 fetuses with CTM included TOF (n = 32), TGA (n = 29), DORV (n = 22), and TA (n = 8). The great arterial spatial relationship was diagnosed accurately in 84 of the 91 (92%) live-born infants. In the other seven infants with DORV, the great arterial spatial relationship was identified inaccurately. The overall survival to 30 days was 85 of 91 (93%). Twenty-three of 91 (25%) patients had extracardiac anomalies. Genetic diagnosis (amniocentesis) was obtained in 63 of 94 patients; 11 (17%) had chromosomal abnormalities. Maternal glucose tolerance results were obtained in 65 of the 91 patients and were abnormal in 25 of 65 (38%). Prenatal diagnostic accuracy of conotruncal malformations is excellent; the arterial spatial relationship of DORV remains problematic. The populations of fetuses with CTMs who continue to develop to term have an excellent prognosis.
We have investigated the chromosomal location, inheritance, and expression of a cloned rabbit beta-globin gene introduced into the mouse germ line by microinjection into mouse eggs. Experiments utilizing in situ hybridization to metaphase chromosomes show that the gene has integrated into one or two different chromosomal loci in each of five mouse lines analyzed. Each locus contains between three and forty copies of the foreign DNA sequence arranged in a tandem array, and the sequences at each locus are stably inherited as a single Mendelian marker. Neither globin mRNA nor polypeptides encoded by the rabbit beta-globin gene are detected in erythroid cells in the seven transgenic lines examined, indicating that the expression of the foreign gene is not correctly regulated. However, in two of the mouse lines, rabbit beta-globin transcripts are found at a low level in specific, although inappropriate, tissues: skeletal muscle in one line and testis in another line. These unusual patterns of beta-globin gene transcription are heritable traits in the two mouse lines and may result from the beta-globin gene's integration at abnormal chromosomal positions.
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BACKGROUND: Screening for trisomy 21 by a combination of maternal age, fetal nuchal translucency (NT) thickness and maternal serum free beta-hCG and pregnancy associated plasma protein-A (PAPP-A) at 11-13(+6) weeks of gestation is associated with a detection rate of 90%, for a false-positive rate of 5%. Recent evidence suggests that in about 70% of fetuses with trisomy 21 the nasal bone is not visible at the 11-13(+6) week scan and that the frequency of absence of nasal bone differs in different ethnic groups. In addition, there is a relationship between absent nasal bone and nuchal translucency thickness. In a preliminary study we showed that while PAPP-A levels were lower and free beta-hCG levels were higher in trisomy 21 fetuses with an absent nasal bone, this difference was not statistically different. In fetuses with trisomy 13 and trisomy 18, there is also a high (57 and 67%) incidence of an absent nasal bone. The aim of this present study was to extend our examination of whether the level of maternal serum biochemical markers is independent of the presence or absence of the nasal bone in cases with trisomy 21 and to ascertain if any differences exist in cases with trisomies 13 and 18. METHODS: This study data comprised 100 trisomy 21 singleton pregnancies at 11-13(+6) weeks of gestation from our previous study and an additional 42 cases analysed as part of routine OSCAR screening. A total of 34 cases with trisomy 18 and 12 cases with trisomy 13 were also available. Ultrasound examination was carried out for measurement of fetal NT and assessment of the presence or absence of the fetal nasal bone. Maternal serum free beta-hCG and PAPP-A were measured using the Kryptor rapid random access immunoassay analyser (Brahms Diagnostica AG, Berlin). The distribution of maternal serum free beta-hCG and PAPP-A in chromosomally abnormal fetuses with absent and present nasal bone was examined. RESULTS: The nasal bone was absent in 29 and present in 13 of the new trisomy 21 cases and in 98 (69%) and 44 respectively in the combined series. For the trisomy 18 cases, the nasal bone was absent in 19 (55.9%) cases and in 3 (25%) of cases of trisomy 13. There were no significant differences in median maternal age, median gestational age, NT delta, free beta-hCG MoM and PAPP-A MoM in trisomy 21 fetuses with and without a visible nasal bone, and similarly for those with trisomies 13 or 18. For a false-positive rate of 5%, it was estimated that screening with the four markers in combination with maternal age would be associated with a detection rate of 96% of cases with trisomy 21. For a false-positive rate of 0.5%, the detection rate was 88%. CONCLUSIONS: There is no relationship between an absent fetal nasal bone and the levels of maternal serum PAPP-A or free beta-hCG in cases with trisomies 13, 18 or 21. An integrated sonographic and biochemical test at 11-13(+6) weeks can potentially identify about 88% of trisomy 21 fetuses for a false-positive rate of 0.5%.
Lymphocytes from 33 out of 63 patients with B-cell chronic lymphocytic leukaemia (B-CLL) were successfully stimulated for cytogenetic analysis by means of two B-cell mitogens: pokeweed mitogen and lipopolysaccharide-B, used after pretreatment of the cells with neuraminidase and galactose oxidase. All patients had abnormal clones in 30-100% of the cells analysed. Chromosomes more frequently involved were Nos. 1, 3, 6, 11, 12, 13 and 14. The most common abnormality was a marker 14q+ (breakpoint 14q32) seen in 17 cases; trisomy 12 was observed in seven cases. A clinical scoring system was used to investigate the correlation of chromosome abnormalities with prognosis. The group with 14q+ was often associated with features of progressive disease, namely; prolymphocytoid or Richter transformation, refractoriness to therapy, high WBC and advanced staging. A significant difference in survival was observed between patients with 14q+ and the rest: median survival from diagnosis being 45 months and over 64 months, respectively (P less than 0.05); when survival was calculated from the time of chromosome analysis the values were 8 months and more than 41 months, respectively (P less than 0.01). It is suggested that 14q+ is acquired during the evolution of CLL and that this development may be a key event in the clinical progression of B-CLL. Other abnormalities, including trisomy 12, were not found to be associated with a worse prognosis.
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Lymphocytes from a patient with chronic lymphocytic leukaemia, in whom therapy was ineffective, were defined as thymus-derived (T) cells by membrane markers (sheep erythrocyte rosettes, complement rosettes, surface immunoglobulin). The lymphocytes responded weakly to two mitogens, phytohaemagglutinin and the calcium ionophore A23187, but not to concanavalin A. Cytogenetic studies of leukaemic cells from unstimulated and mitogen-stimulated cultures revealed an abnormal karyotype with 45 chromosomes and multiple rearrangements. The T cell variant of classical chronic lymphocytic leukaemia is relatively rare; additional reports are needed to determine if the clinical course is typically less benign than in the common B cell variety, or whether this patient simply represented a late, unresponsive phase of the disease.