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Biomedical subjects

M C Baker

Publications and source records attributed to M C Baker.

At least 37 records · Page 2Linked to original sources
PubMed1991

Small metacentric marker chromosomes in unbanded archival material from carcinomas of the cervix uteri.

Since a small metacentric marker chromosome, probably an isochromosome for the short arm of chromosome 5, was found in about three-quarters of carcinomas of the cervix in recent studies using chromosome banding techniques, 36 tumours from the prebanding era which yielded excellent chromosome spreads were reviewed: it was found that a similar proportion of these tumours had a small metacentric marker, on average 38% longer than the chromosomes 19 and 20, often in two copies. The marker was also seen in one of two cervical carcinomas in situ. This study on archival material lends support to the view that the marker represents a characteristic and significant finding in this class of tumour.

Chromosome Aberrations↗
PubMed1990

Chromosome changes in 43 carcinomas of the cervix uteri.

A summary of the chromosome changes in 43 carcinomas of the cervix studied by a direct technique showed that the most common anomaly was a small metacentric [in 77%, often in two copies: an i(5p) or possibly an i(4p)]. Others commonly involved in structural changes were: chromosome 1 (60%; most commonly an i(1q), 1p-, or translocation of part of 1q onto another chromosome); chromosome 17 (47%; translocations onto the short arm or long-arm isochromosomes), chromosome 11 (37%; translocations onto the short arm); chromosome 3 (26%; including 3p- and 31-); and chromosomes 2, 6, and 9 (each in 19%). Considering the four most frequent categories of markers--small metacentrics and markers derived from chromosomes 1, 17, and 11, none of which is specific for cervical carcinoma--almost any combination of these four might be present in a tumor (and at least one was present in all tumors) so that they were not mutually exclusive. Estimates of the average numbers of normal chromosomes based on representative karyotypes from 35 of the tumors showed that three chromosomes in particular were underrepresented (chromosomes 4, 11, and 14; 72-73% of the expected values), while chromosomes 3, 19, and 20 were those most highly represented (99-103%).

Adenocarcinoma↗
PubMed1989

Chromosome 17p loss in carcinoma of the cervix uteri.

Markers derived from chromosome 17 were present in 13 (42%) of 31 carcinomas of the cervix uteri. Altogether, 14 such markers were present, ten of which were 17p+ chromosomes with a small amount of additional material, probably of variable origin, while three were i(17q)s. The significance of the chromosome 17 aberrations in cervical carcinoma may lie in the loss of recessive genes on 17p.

Carcinoma↗
PubMed1989

Value of aceto-orcein squash preparations in the cytogenetic study of solid tumours.

The value of aceto-orcein squash preparations as a routine initial step in the cytogenetic study of solid tumours is pointed out. This simple procedure allows a rapid evaluation to be made of various characteristics of the tumour, including the ploidy level, as well as a definitive assessment of nuclear phenomena including the incidence of X-chromatin bodies. Evaluation of the latter in normal as well as tumour cells led to the discovery of unsuspected congenital sex chromosome anomalies in two patients in this laboratory.

Adenocarcinoma↗
PubMed1989

A comparison of the number of X-chromatin bodies and of X chromosomes in carcinomas of the cervix uteri.

The number of X-chromatin bodies in interphase cells was compared with the number of X chromosomes in metaphases in nineteen carcinomas of the cervix uteri. This is the first time that such a direct comparison has been made. Nine tumours had a single X-chromatin body, four had two bodies and six were X-chromatin negative. Thus, a total of seventeen X-chromatin bodies was present in these tumours which collectively had forty-seven X chromosomes. Surprisingly, three tumours with near diploid complements were X-chromatin negative although they had two X chromosomes. The findings suggest that duplication of the active X is advantageous during tumour development while the inactive, X-chromatin forming, X chromosome tends to be lost.

Adult↗
PubMed1988

Small metacentric marker chromosomes, particularly isochromosomes, in cancer.

At least two types of small metacentrics, which are isochromosomes for 12p and either 4p or 5p, respectively, are significantly associated with certain types of cancer and their formation may represent important stages in the development of these tumours. The specificity of the i(12p) for testicular cancer is now well established (it may also be present, however, in dysgerminomas and mixed Müllerian tumours of the ovary). This review is therefore mainly concerned with another marker, probably an i(5p) although an i(4p) should also be considered. Recent data suggest that this marker represents a significant chromosomal change occurring with a fairly high frequency in a variety of cancers, including carcinomas of the cervix, ovary, breast, bladder and bronchus (excluding small-cell carcinomas). These isochromosomes may contribute to tumour development through gene amplification; consistent with this is the frequent presence of these markers in two or more copies.

Chromosome Aberrations↗
PubMed1988

Squamous cell carcinoma of the skin with an unusual marker chromosome.

Chromosome studies were undertaken on uncultured material from a primary anaplastic squamous cell carcinoma of the skin from a female aged 81. The modal chromosome number was 42. Four marker chromosomes were present in most metaphases: a der (1) which resulted in tetrasomy for most of 1q, a giant chromosome consisting of most of a chromosome 2 and 4q, a small metacentric which was probably an isochromosome for 4p or 5p, and a small chromosome, considered to be an 18q+. The latter was conspicuous in unbanded orcein-stained preparations owing to the presence of a virtually nonstaining region on its long arm. These findings are of interest in the light of the paucity of data on this type of tumour.

Aged↗
PubMed1987

Abnormal chromosomes including small metacentrics in 14 ovarian cancers.

In direct preparations of 14 ovarian cancers including 11 primary tumors, chromosomes #1 (12 tumors), #3 (12 tumors, including 3q- chromosomes in five), #6 [eight tumors, including six with a 6q- and two with an i(6p)], #11 (11p + in seven tumors), and #14 (14q+ in at least seven tumors) were most frequently involved in structural aberrations. Also, abnormal small metacentrics were seen in 11 tumors. In ten of these the chromosome appeared to be an i(4p) or i(5p) and in one of these, a mixed Müllerian tumor, there was also an i(12p); the latter anomaly was also present (in duplicate) in a dysgerminoma.

Adult↗
PubMed1986

Radiation damage in patients treated by total-body irradiation, bone marrow grafting, and cyclosporin.

The bone marrow (BM) and peripheral blood (PB) from 63 patients were assessed for the presence of chromosomal aberrations after bone marrow transplantation (BMT) following total body irradiation (TBI) for leukemia. Forty-one patients showed no abnormalities in either BM or PB, and 22 had aberrations in either BM or PB or both. Only stable aberrations were found in the BM, but both stable and unstable abnormalities were present in the PB, the majority showing only unstable aberrations. Among the 25 patients who had a leukemic relapse, clonal chromosomal abnormalities were found in the BM of 12 out of the 16 cases for whom marrow was studied at the time of the relapse. A statistically significant negative correlation between leukemic relapse and graft versus host disease (GvHD) was found, but the relationships between chromosome damage and leukemic relapse, GvHD, and the pretransplant radiation dose and between the radiation dose and both leukemic relapse and GvHD were not significant.

Adolescent↗
PubMed1985

Cytogenetic study of ten carcinomas of the bladder: involvement of chromosomes 1 and 11.

In direct preparations of ten untreated transitional cell carcinomas of the bladder, chromosomes #1 and #11 were most frequently involved in structural changes (in at least seven tumors each). Three tumors had one or two 11p- chromosomes, and, in other tumors, chromosome #11 had taken part in translocations or isochromosome formation, which, except in one tumor, resulted in a loss of short arm material. Also, there was a tendency for the presence of fewer than expected normal chromosomes #11. Chromosome #1 anomalies are common in most types of tumor; however, chromosome #11 abnormalities, particularly the loss of short arm material, are not common and may thus characterize carcinoma of the bladder, a finding that is of interest in view of the location of an oncogene, c-Ha-ras1, on 11p. Translocations probably involved chromosome #17 in four tumors. Structurally changed chromosomes #3 were seen in four tumors, including one or two 3q- chromosomes in two or possibly three tumors.

Adult↗