Activity satellite association and polymorphism of Ag stained nucleolus organizer regions (Ag+ NORs) in lymphocytes from women with cervical uterine cancer.

Thirty five female patients with different stages of neoplastic lesions: cervical intraepithelial neoplasia (CIN) or dysplasia (CIN I and CIN II), in situ carcinoma (CIS), and adenocarcinoma, and 27 healthy women (controls) were studied to determine the activity, satellite association, and polymorphism of Ag stained nucleolus organizer regions (Ag+ NORs) in acrocentric chromosomes in metaphases obtained from peripheral blood lymphocytes. For each person, 25 to 50 metaphases stained with ammoniacal silver technique were scored. The average number of Ag+ NORs was higher in women with adenocarcinoma (7.66 +/- 0.72) than in controls (6.65 +/- 0.74). Non-associated chromosomes showing Ag+ NORs were found more frequently in patients (5.85 +/- 0.88) than in controls (4.81 +/- 0.67). Patients aged 30-39 and 60 or more had an increase of Ag+ NORs (7.99 +/- 1.04, and 7.81 +/- 0.71) with respect to their controls (6.36 +/- 0.052 and 6.17 +/- 0.88), but the frequency of satellite association showed lower values in 50-59 year-old patients (0.75 +/- 0.08) than in controls (1.02 +/- 0.19). The most frequent association in patients was the large type (patients = 38.96%, controls = 30.49%). The partial association showed higher values (6.49%) than controls (2.44%). Otherwise, the spherical association was more frequent for controls (37.80%) than for patients (28.57%). All these differences were statistically significant (p < 0.05). The frequency of Ag+ NORs and the type of polymorphism of satellite association could be related to the neoplastic process, while the frequency of satellite association and of polymorphism of Ag+ NORs seems to be irrelevant.

Activity satellite association and polymorphismo of Ag stained nucleolus organizer regions (Ag+ NORs) in lymphocytes from women with cervical uterine cancer

Thirty five female patients with different stages of neoplastic lesions: cervical intraepithelial neoplasia (CIN) or dysplasia (CIN I and CIN II), in situ carcinoma (CIS), and adenocarcinoma, and 27 healthy women (controls) wee studied to determine the activity, satellite association, and jpolymorphism of Ag stained nucleolus organizer regions (Ag+NORs) in acrocentric chromosomes in metaphases obtained from peripheral blood lymphocytes. For each person, 25 to 50 metaphases stained with ammoniacal silver technique were scored. The average number of Ag+ NORs was higher in women with adenocarcinoma (7.66 ñ 0.72) than in controls (6.65 ñ 0.74). Non-associated chromosomes showing Ag+ NORs were found more frequently in patients (5.85 ñ 0.88) than in controls (4.81 ñ 0.67). Patients aged 30-39 and 60 or more had an increase of Ag+ NORs (7.99 ñ 1.04, and 7.81 ñ0.71) with respect to their controls (6.36 ñ 0.052 and 6.17 ñ 0.88), but the frequency of satellite association showed lower values in 50 -59 year-old patients (0.75 ñ 0.08) than in controls (1.02 ñ 0.19). The most frequent association in patients was the large type (patients = 38.96 perecent, controls 30.49 ). The partial association showed higher values (6.49 percent) than controls (2.44 percent). Otherwise, the spherical association was more frequent for controls (37.80 percent) than for patients (28.57 percent). All these differences were statistically significant (p<0.05). The frequency of Ag+ NORs and the type of polymorphism of satellite association could be related to the neoplastic process, while the frequency of satellite association and of polymorphism of Ag+ NORs seems to be irrelevant

Double in situ hybridization in combination with digital image analysis: a new approach to study interphase chromosome topography.

Double in situ hybridization with mercurated and biotinylated chromosome specific DNA probes in combination with digital image analysis provides a new approach to compare the distribution of homologous and nonhomologous chromosome targets within individual interphase nuclei. Here we have used two DNA probes representing tandemly repeated sequences specific for the constitutive heterochromatin of the human chromosomes 1 and 15, respectively, and studied the relative arrangements of these chromosome targets in interphase nuclei of human lymphocytes, amniotic fluid cells, and fibroblasts, cultivated in vitro. We have developed a 2D-image analysis approach which allows the rapid evaluation of large numbers of interphase nuclei. Models to test for a random versus nonrandom distribution of chromosome segments are discussed taking into account the three-dimensional origin of the evaluated 2D-distribution. In all three human diploid cell types the measurements of target-target and target-center distances in the 2D-nuclear image revealed that the labeled segments of the two chromosomes 15 were distributed both significantly closer to each other and closer to the center of the nuclear image than the labeled chromosome 1 segments. This result can be explained by the association of nucleolus organizer regions on the short arm of chromosome 15 with nucleoli located more centrally in these nuclei and does not provide evidence for a homologous association per se. In contrast, evaluation of the interphase positioning of the two chromosome 1 segments fits the random expectation in amniotic fluid and fibroblast cells, while in experiments using lymphocytes a slight excess of larger distances between these homologous targets was occasionally observed. 2D-distances between the labeled chromosome 1 and 15 segments showed a large variability in their relative positioning. In conclusion our data do not support the idea of a strict and permanent association of these homologous and nonhomologous targets in the cell types studied so far.

Intensity heteromorphisms of human chromosome 15p by DA/DAPI technique.

We suggest that the short arms of human chromosome 15 (15p) exhibit intensity heteromorphisms by DA/DAPI technique. A method for classification of variable intensities is proposed. The different intensities can be classified into at least five classes. They are: negative, pale, medium, intense, and brilliant. Therefore we suggest that 15p is not always positive by DA/DAPI technique. The present findings reveal that the heteromorphism on 15p is far greater than previously thought.

High resolution chromosome analysis of constitutional and acquired t(15;17) maps c-erbA to subband 17q11.2.

High resolution chromosome analysis was performed on bone marrow cells from four patients with acute promyelocytic leukemia and t(15;17), and in lymphocytes from two unrelated, phenotypically normal persons with an apparently identical constitutional translocation. Scrutiny of prophase-prometaphase chromosomes localized the breakpoints in all six cases to subbands 15q22.3 and 17q11.2. Molecular genetic studies have localized the oncogene c-erbA to chromosome #17 between the breakpoints of the constitutional and the acquired anomaly. The present results, therefore, map c-erbA to subband 17q11.2.

Amplification and rearrangement of Hu-ets-1 in leukemia and lymphoma with involvement of 11q23.

The Hu-ets-1 oncogene was found to be rearranged and amplified 30-fold in one case of acute myelomonocytic leukemia in which a homogeneously staining region occurred on 11q23; the oncogene was rearranged and amplified approximately tenfold in a case of small lymphocytic cell lymphoma with an inverted insertion that also involved band 11q23. This work suggests that Hu-ets-1 is an unusual oncogene that can help explain the common involvement of chromosome band 11q23 in various subtypes of hematopoietic malignancies.

Retinoblastoma in Lebanon.

The data on 58 patients with retinoblastoma managed at the American University of Beirut, Medical Center over the last 35 years is reviewed. The epidemiology, genetics and clinical features of this tumor appear to be the same in the Middle-East as well as the rest of the world. The notable difference between the data in this study and that from other studies is the marked delay in diagnosis of the tumor in this part of the world leading to a higher incidence of extraocular extension, a more advanced stage of the disease and poorer survival rates. This seems to be a feature of medically underdeveloped societies. Increased public awareness of the early signs and symptoms of the disease, as well as routine fundoscopy on all infants are advocated to improve early detection, leading to improved survival rates and prevention of unnecessary enucleations.

Proximal duplications of chromosome 15: clinical dilemmas.

The apparently rare cytogenetic abnormality of partial trisomy 15 was diagnosed by the authors in a patient presenting with developmental retardation, macrocephaly with ventricular enlargement and prominent subarachnoid spaces, hypotonia, low-set ears, hyperextensible wrists and hands, high arched palate, tapering fingers, right esotropia, and bilateral metatarsus adductus. Clinical findings in this case are similar to previously reported cases of proximal duplications of chromosome 15 and bear some similarity to the Prader-Willi syndrome. However, our patient did not have the severe hypotonia, early failure to thrive, or genital abnormalities seen in classical Prader-Willi syndrome. This case supports the theory that a variety of cytogenetic aberrations in proximal 15q can cause a "Prader-Willi-like" syndrome. Increased clinical suspicion is needed when patients are seen with hypotonia, retarded development and mild dysmorphism if the variety of phenotypes are to be delineated.

Familial transmission of a non-Robertsonian translocation dicentric.

A second family showing transmission of a dicentric through three generations involving chromosomes 13 and 18 is presented. Features of non-Robertsonian dicentric chromosomes are presented and discussed.

High resolution pattern of an inverted duplication (15).

The nature and the origin of a supernumerary marker chromosome in a mentally retarded boy were determined by various staining techniques on metaphase chromosomes and by GBG high resolution technique. The karyotype was found to be 47,XY, + inv dup(15) (pter----q13: :q13----pter) and the supernumerary chromosome was of maternal origin.

Nonrandom chromosomal changes in retinoblastomas.

The analysis of the karyotype in 76 retinoblastomas (24 our cases and 52 described in the literature) has revealed nonrandom changes of Iq, 6p, 13, 16 and the sex chromosomes. Complete or partial trisomy Iq was observed in 44 out of 76 tumours. Tetra-or trisomy 6p was found in 35 and 6 cases respectively. Chromosome 13 monosomy or its long arm deletion was described in 11 tumours. Monosomy 16 and loss of the X or Y--in 18 and 12 cases. The specific feature of retinoblastoma karyotype is presence (along with two normal homologues of the pair 6) of the marker chromosome i (6p). Possible causes of unexpectedly rare abnormalities of chromosome 13 in retinoblastoma cells were discussed in the light of well known data on predisposing role of constitutional deletion 13q14, and recent molecular genetic studies showing the significance of recessive tumour genes in carcinogenesis. The cytological signs of gene amplification (HSRs, DMs) were revealed in few retinoblastomas. However, the recent data on N-myc gene amplification and its elevated expression in several retinoblastomas indicate that amplification of the oncogene(s) might be involved in the genesis of this tumour. Further studies are needed to understand the correlative role of specific chromosome rearrangements, gene(s) amplification and action of recessive rb gene, located at 13q14 in initiation and progression of retinoblastoma.

Fusion of an immunoglobulin variable gene and a T cell receptor constant gene in the chromosome 14 inversion associated with T cell tumors.

An inversion of chromosome 14, inv(14)(q11,q32), is frequently observed in human T cell tumors; the cytogenetic breakpoints are of interest because the T cell receptor alpha-chain and immunoglobulin heavy chain genes reside on chromosome bands 14q11 and 14q32, respectively. We have investigated the structure of the alpha-chain genes in a T cell line harboring the chromosome 14 inversion. On the normal chromosome 14, a V alpha segment has rearranged nonproductively with a J alpha segment. In contrast, the inverted chromosome features an unprecedented rearrangement in which an immunoglobulin heavy chain variable gene segment (VH) on chromosome band 14q32 has joined with a J alpha segment from band 14q11. The VH-J alpha C alpha rearrangement is productive at the genomic level and therefore may encode a hybrid immunoglobulin/T cell receptor polypeptide.

Nucleotide sequence of a t(14;18) chromosomal breakpoint in follicular lymphoma and demonstration of a breakpoint-cluster region near a transcriptionally active locus on chromosome 18.

The t(14;18)(q32;21) chromosomal translocation characteristic of follicular lymphomas is the most common cytogenetic abnormality known to be associated with any specific type of hematolymphoid malignancy. A fragment of DNA containing the crossover point between chromosomes 14 and 18 was cloned from the tumor cells of a patient with a follicular lymphoma carrying this translocation. Nucleotide sequence analysis of the breakpoint DNA revealed that the break in chromosome 14 occurred in joining region 4(J4) of the nonfunctional immunoglobulin heavy chain allele. This finding and other structural similarities of the breakpoint with the functional diversity region-joining region (D-J) joint in this lymphoma suggest that D-J recombination enzymes played a role in the mechanism of the t(14;18) translocation. Hybridization analysis of DNA from 40 follicular lymphomas showed that the majority of t(14;18) translocations occur on chromosome 18 DNA within 4.2 kilobases of the cloned breakpoint. A DNA probe from this breakpoint-cluster region detects transcription products in the tumor cells from which it was cloned and in a B-lymphoma cell line containing a t(14;18) translocation.

The t(14;18) chromosome translocations involved in B-cell neoplasms result from mistakes in VDJ joining.

In this study, the joining sequences between chromosomes 14 and 18 on the 14q+ chromosomes of a patient with pre-B-cell leukemia and four patients with follicular lymphoma carrying a t(14;18) chromosome translocation were analyzed. In each case, the involved segment of chromosome 18 has recombined with the immunoglobulin heavy-chain joining segment (JH) on chromosome 14. The sites of the recombination on chromosome 14 are located close to the 5' end of the involved JH segment, where the diversity (D) regions are rearranged with the JH segments in the production of active heavy-chain genes. As extraneous nucleotides (N regions) were observed at joining sites and specific signal-like sequences were detected on chromosome 18 in close proximity to the breakpoints, it is concluded that the t(14;18) chromosome translocation is the result of a mistake during the process of VDJ joining at the pre-B-cell stage of differentiation. The putative recombinase joins separated DNA segments on two different chromosomes instead of joining separated segments on the same chromosome, causing a t(14;18) chromosome translocation in the involved B cells.

Light and scanning electron microscopy of the same human metaphase chromosomes.

A technique has been developed to examine the same G-banded human metaphase chromosomes, first in the light microscope and then in the scanning electron microscope (SEM). A structural involvement in chromosome banding was confirmed by a positional correlation between the G-positive bands observed in the light microscope and the circumferential grooves between the quaternary coils of the metaphase chromosomes, observed in the SEM. In further support of this the regions between the grooves showed a positional relationship with the G-negative or reverse (R) bands. The examination of slightly extended metaphase chromosomes in the light microscope demonstrated that the G-banding pattern corresponded to that described by the Paris nomenclature for metaphase chromosomes. The arrangement of the circumferential grooves of the same chromosomes, observed in the SEM, was shown to relate to that described by the Paris nomenclature for prometaphase chromosomes. Therefore, using the SEM it is possible to demonstrate the details of prometaphase banding in metaphase chromosomes.