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Biomedical subjects

U Bonk

Publications and source records attributed to U Bonk.

At least 19 recordsLinked to original sources
PubMed1996

A fibroadenoma with a t(4;12) (q27;q15) affecting the HMGI-C gene, a member of the high mobility group protein gene family.

An intracanalicular fibroadenoma of the breast showing a clonal chromosomal aberration t(4;12) (q27;q15) as the sole cytogenetic abnormality is described. In order to narrow down the breakpoint region on chromosome 12 on the molecular level we performed fluorescence in situ hybridization (FISH) analysis with a cosmid pool originating from a YAC-contig overspanning part of the region 12q14-15. We were able to narrow down the breakpoint to an approximately 230kb fragment belonging to the HMGI-C gene which maps within an area recently designated as MAR (Multiple Aberration Region). The chromosomal breakpoints of other frequent benign solid tumors, i.e. lipomas, uterine leiomyomas, and pleomorphic adenomas are clustered within the third intron of that gene.

Adolescent↗
PubMed1996

Significance of clonal chromosome aberrations in breast fibroadenomas.

Despite the high frequency of fibroadenomas of the breast, cytogenetic results are relatively limited. We describe our cytogenetic findings in 30 fibroadenomas. Of these, three showed clonal chromosome abnormalities, i.e., 46,XX,der(6)t(1;6)(q25;p21.3); 48,XX,del(6)(q21),r(11)(?),der(14)t(6;14)(q21;q32),+2mar; and 47,XX,+5.

Adolescent↗
PubMed1996

Structural aberrations of chromosome 6 in three uterine smooth muscle tumors.

Clonal karyotypic alterations of chromosome 6 in three uterine smooth muscle tumors are reported. In all cases an apparently identical breakpoint on the short arm of chromosome 6 was found. Two cases displayed the histologic features of cell-rich myomas with severe nuclear atypia but no clear evidence for malignancy. The remaining case was a primary uterine leiomyosarcoma of an 80-year-old patient showing an apparently balanced reciprocal chromosomal translocation, t(1;6)(p32-33;p21.3), as the sole karyotypic abnormality. This type of aberration has not been reported before in leiomyosarcomas. Because of the nuclear atypia in the other myomas with a breakpoint involving the short arm of chromosome 6 we feel that this cytogenetically recognizable but rare subgroup of uterine smooth muscle tumors warrants a careful clinical follow-up.

Adult↗
PubMed1995

Telomere repeat fragment sizes do not limit the growth potential of uterine leiomyomas.

We have compared the length of telomere repeat fragments (TRF's) in 19 uterine leiomyomas from 6 patients with the corresponding myometrium. The advantage of this study of TRF length is that cells from uterine leiymyoma and cells from corresponding myometrium do not contain any considerable proportions of other cells as revealed by analysis of clonality. In all tumor samples a loss of TRF length ranging from 1120 to 4690 bp was noted. There was no correlation between tumor volume or size of tumor population as revealed by histological examination and loss of TRF length. From the obtained TRF length data (an average myometrial TFR length of 13 kb and an average loss of TRF length in myoma cells of 83 bp per cell division) we concluded that TRF length reduction does not limit the growth potential of uterine leiomyomas.

Base Sequence↗
PubMed1995

Trisomy 8 and 18 as frequent clonal and single-cell aberrations in 185 primary breast carcinomas.

For cytogenetic investigations short-term cultures of 185 breast carcinomas (135 invasive ductal, 21 invasive lobular, 12 invasive ductal with intraductal components, seven heterogeneous, six intraductal, four invasive ductal and lobular) were prepared. Cytogenetic examinations revealed clonal abnormalities in 39 cases with a predominance of simple numerical chromosome changes, i.e., trisomies of chromosomes 7, 8, and 18. One hundred forty-six tumors did not show clonal abnormalities, but single-cell aberrations other than monosomies occurred in 79 of these tumors. Compared to cells of epithelial hyperplasia of the breast, amniotic fluid cells, and cells from pleomorphic adenomas cultivated using the same medium, the frequency of single-cell trisomies was significantly higher. Trisomy 8 was not only found as a clonal aberration in 10 cases but was also the most frequent non-clonal aberration. Trisomy 7 and 18 were also frequent clonal as well as non-clonal cytogenetic deviations.

Adult↗
PubMed1994

Evidence that metacentric and submetacentric chromosomes in canine tumors can result from telomeric fusions.

We have hypothesized that metacentric and submetacentric chromosomes frequently observed in malignant canine tumors are a result of telomeric fusions. Therefore cells from a canine mammary pleomorphic adenoma were transformed with a plasmid containing the SV40 'early region', known to cause telomeric associations. Compared with non-transformed adenoma cells, the cells had a higher proliferative capacity and expressed the large SV40-T-antigen. Karyotype studies showed the conversion from a normal to an aberrant karyotype with an increase of bi-armed chromosomes resulting from fusions of acrocentric chromosomes. In addition, the length of the telomeric repeats (TTAGGG) was determined for an early and a late passage of the transformed cells by Southern hybridization. The length of the telomeric repeats was apparently longer in the 5th than in the 38th passage. In situ hybridization with a telomere-specific DNA revealed interstitial telomeric repeats in the bi-armed chromosomes. We have concluded that these findings reflect the clonal expansion of head-to-head-telomeric fusions of canine acrocentric chromosomes leading to dicentric chromosomes with a very short distance between the two centromeres. Our results support the idea that the apparent centric fusions that have been described in some canine tumors may in fact be the cytogenetic products of head-to-head-telomeric fusions.

Adenoma, Pleomorphic↗
PubMed1993

Trisomy 8 as a recurrent clonal abnormality in breast cancer?

The results of cytogenetic investigations on one benign and 15 malignant breast tumors are described. Trisomy 7, 8, 18, and 21 and monosomy X occurred as clonal numerical aberrations, and inv(7)(q21q31) and t(4;12)(q21;p13) occurred as clonal structural aberrations. Only trisomy 8 was a recurrent karyotypic abnormality, however. Thus, we assumed that trisomy 8 as an early genetic change characterizes a subtype of ductal breast carcinomas.

Adult↗
PubMed1987

Standardizing microcolposcopy. Assessing the criteria for evaluating the presence and degree of cervical intraepithelial neoplasia.

We established criteria for the detection and grading of cervical intraepithelial neoplasia with microcolposcopy. These criteria were assessed for their accuracy through comparison with the histologic evaluation of cone biopsy or hysterectomy specimens in 26 highly selected cases. There was a positive correlation of 88.5% and no false-negative cases. Microcolposcopy, performed in a standardized manner, may be a valuable adjuvant to colposcopy.

Biopsy↗
PubMed1980

Double appendix.

A case of appendix duplication is described. A normal appendix was present in the usual position while a rudimentary second appendix was found to arise separately from the cecum.

Adult↗
PubMed1979

[Tissue compatibility of gentamycin PMMA beads and chains (author's transl)].

In chronic bone tissue infections a very effective local antibiotic therapy can be achieved by temporary implantation of Gentamycin-PMMA beads. Eight weeks later the chains were removed and the surrounding specimens of bone were subjected to histological examination. On the basis of the results, it was established that the beads were encapsulated in neutrophile granulocytes, collagen fibers and foreign giant cells.

Acrylic Resins↗
PubMed1976

[Adenomatoid tumors in myometrium (author's transl)].

In 6000 cases of hysterectomy nine adenomatoid tumors of myometrium were observed. Macroscopically, the adenomatoid tumour appears as a round or ovoid mass of grey or whitegrey colour about the size of a hazel-nut. Microscopically, four types are distinguished: solid, angiomatoid, macrotubular and mixed types. The cytoplasma of the cells tends to be vacuolated, the glandlike spaces being probably derived by confluence of these vacuoles. The interstitial tissue contains cells of the same type and often lymphocytes. Several hypotheses concerning the histogenesis of adenomatoid tumors are reviewed. The adenomatoid tumor is more frequent in the myometrium than it has been hitherto known. Probably the tumor is often misinterpreted as leiomyoma of the uterus on the basis of macroscopical appearance only.

Adenoma↗