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Biomedical subjects

S Heim

Publications and source records attributed to S Heim.

At least 343 records · Page 19Linked to original sources
PubMed1985

Telomeric association in a malignant fibrous histiocytoma.

In a malignant soft-tissue fibrous histiocytoma 50-56 chromosomes were found in the majority of the metaphases. The most frequent numerical aberrations were one or two extra copies of chromosomes 4, 5, 18, 20, 22, and a missing chromosome 15. Structural rearrangements encountered were 11p+ and 1-5 unidentifiable markers. The most conspicuous feature was pairs of chromosomes intimately associated or fused at their telomeres, observed in 20 out of 22 metaphases. Although the telomeres of 6p, 11p, 16q, 20q, and 21p were involved most frequently, no preferential pattern of associations was detectable. This peculiar chromosomal behavior is compared to similar observations recently reported in a case of a B-cell lymphoid leukemia.

Chromosome Aberrations↗
PubMed1985

Constitutional C-band pattern in patients with adenomatosis of the colon and rectum.

The pattern of polymorphism in the C-band-positive constitutive heterochromatin of chromosomes #1, #9, and #16 was studied in fibroblasts from 23 unrelated patients with adenomatosis of the colon and rectum and in peripheral lymphocytes from 78 control persons. The parameters of the heterochromatic regions analyzed were relative size, symmetry-asymmetry within homologous chromosome pairs, and frequency of inversions. The polyposis coli patients had a significantly higher frequency (p less than 0.05) of partial and total heterochromatin inversion on chromosome #9 than the control group (37.0% compared with 21.8%). In the other parameters studied, no significant differences were found between patients and controls.

Chromosome Banding↗
PubMed1985

Variant Ph translocations in chronic myeloid leukemia.

Variant translocations were found in eight of 142 consecutive patients with Ph-positive, chronic myeloid leukemia encountered in our laboratory during the last decade. Two patients had simple, two-way variant translocations: t(17;22)(p13;q11) and t(16;22)(q24;q11). Both of these patients had an additional translocation involving chromosomes #9: t(7;9)(q22;q34) and t(9;17)(q34;q21), respectively. Complex variant translocations were found in four cases: t(2;9;22)(p23q12;q34;q11), t(3;9;22)(p21;q34;q11), t(9;12;22)(q34;q13;q11q13), and t(13;17;22)(p11;p11q21;q11). In two cases, the only discernable cytogenetic aberration was del(22)(q11). A review of the chromosomal breakpoints involved in this series and in 185 cases of variant Ph translocations previously reported in the literature reveals that a disproportionately large number of breakpoints are located in light-staining regions of G-banded chromosomes. Furthermore, the breakpoints in simple variant translocations are more often located in terminal chromosomal regions, whereas, the breakpoints in complex translocations typically affect nonterminal bands. No obvious correlation was detected between variant Ph translocation breakpoints and either fragile sites, oncogene locations, or consistent chromosome breakpoints in other malignancies.

Adult↗
PubMed1985

Increased levels of spontaneous and mutagen-induced chromosome aberrations in skin fibroblasts from patients with adenomatosis of the colon and rectum.

Fibroblast cell strains were established from skin biopsies taken from patients with adenomatosis of the colon and rectum (ACR) and their relatives. A total of 57 different strains (33 from patients and 24 from healthy members of ACR families not at an increased risk for colon polyposis) were tested for their frequencies of spontaneous structural chromosome aberrations, i.e., chromatid and isochromatid gaps, breaks, and interchanges. In 47 strains (27 from patients, 20 from controls), the frequencies of structural chromosome aberrations were also determined after exposing the cells to N-methyl-N'-nitro-N-nitroso-guanidine (MNNG). Both spontaneously and after mutagen treatment, the group of patient strains exhibited, on average, approximately twice the number of chromosome aberrations found in the control group. This increase was highly significant (p less than 0.001), even though there was a considerable overlap between patient and control strains. Treatment with MNNG led to a marked increase in chromosome aberrations in both patients and controls. The small differences in aberration frequencies seen between Gardner and other patient strains were clearly insignificant.

Adolescent↗
PubMed1985

Sister chromatid exchange with and without in vitro mutagen induction in cultured skin fibroblasts from patients with adenomatosis of the colon and rectum.

Fibroblast cell strains were obtained from skin biopsies taken from patients with adenomatosis of the colon and rectum (ACR), and their relatives. A total of 50 different fibroblast strains were tested for their frequencies of sister chromatid exchange (SCE) in vitro. These strains included nine from patients with the Gardner syndrome, 21 from patients with non-Gardner ACR, and 20 cell strains from healthy relatives who were not at an increased risk for ACR. In 23 strains, the SCE frequencies after in vitro exposure to N-methyl-N'-nitro-N-nitroso-guanidine (MNNG) were also determined. Both with and without MNNG induction, SCE values in the Gardner strains were found to be significantly higher than in the control strains (p less than 0.02 and p less than 0.03, respectively). Non-Gardner ACR strains differed only slightly from controls, thus making the difference between the control group and the pooled Gardner + non-Gardner ACR group not significant. In all groups, there was a significant increase in SCE after MNNG exposure, and those strains which had low SCE values spontaneously, also tended to have relatively moderate SCE values after MNNG induction. There was no significant difference between the ratios of SCE values with and without MNNG exposure in the different groups.

Adolescent↗
PubMed1985

Chromosome analysis in 100 cases of first trimester trophoblast sampling.

The cytogenetic findings in 20 experimental and 80 diagnostic cases of first trimester trophoblast biopsy are presented. All samples were obtained between the 8th and 13th week of gestation with the direct vision, trans-cervical technique. Except when fetal sexing because of X-linked disease was the issue, long-term culture with in situ preparation was the method routinely employed in processing the biopsies for cytogenetic analysis. In 78 of the 80 clinical cases and in all reported experimental cases we were successful in establishing a karyotype from the sampled tissue. Unbalanced karyotypes were found in two experimental and six clinical cases. Tetraploidy was found in one clinical case, but was not confirmed in subsequently sampled amniotic fluid cells. In another clinical case, we were unable to confirm in the aborted placenta the trisomy 18 found in the trophoblast biopsy. In the rest of the induced abortions in the clinical series, the karyotype arrived at prenatally has been confirmed, and the 27 babies so far born have been healthy and with phenotypic sex corresponding to the prenatal findings. Six women have miscarried after sampling; in one of these cases the fetus had the karyotype 47,XX, + 13.

Adult↗
PubMed1985

Trophoblast samples suitable for long-term culture.

Chorionic villi were obtained by a direct vision technique. Villi without vessels (38 cases) failed to grow in vitro, irrespective of the amount of tissue. Vascular villi with an estimated weight exceeding 5 mg (71 cases) grew in vitro--with two exceptions.

Biopsy↗
PubMed1983

In vitro growth characteristics of skin fibroblasts from patients with adenomatosis of the colon and rectum and their relatives.

Sub-epidermal biopsies from normal-appearing skin of the upper arm were obtained from patients with adenomatosis of the colon and rectum (ACR) and their relatives. A total of 78 different fibroblast cell strains were tested for their in vitro growth characteristics (plating efficiency, cloning efficiency, growth rate, ability to grow in low-serum medium, cultural morphology, anchorage dependency, contact inhibition at saturation density). The cell strains included 6 from patients with Gardner's syndrome, 25 from patients with ACR without Gardner's syndrome, 9 from "at risk" relatives, and 38 from healthy relatives who were not at an increased risk for ACR. No consistent growth differences were found between the cell strains from the different groups. Instead, this material provides a "normal standard" for in vitro growth characteristics of human skin fibroblasts.

Adolescent↗
PubMedDate not supplied

Evaluation of 1p losses in primary carcinomas, local recurrences and peripheral metastases from colorectal cancer patients.

Cytogenetic and molecular genetic analyses of colorectal adenomas and carcinomas have shown that loss of the distal part of chromosome arm 1p is common, particularly in tumors of the left colon. Because the importance of 1p loss in colorectal cancer metastases is unknown, we compared the frequency, exact site and extent of 1p deletions in primary carcinomas (n=28), local recurrences (n=19) and metastases (n=33) from 67 colorectal cancer patients using 14 markers in an allelic imbalance study. Loss of 1p was found in 50% of the primary carcinomas, 33% of the local recurrences, and 64% of the metastases, revealing a significant difference between the local recurrences and the metastases (P=.04). The smallest region of 1p deletion overlap (SRO) defined separately for each group of lesions had the region between markers D1S2647 and D1S2644, at 1p35-36, in common. The genes PLA2G2A (1p35.1-36) and TP73 (1p36.3) were shown to lie outside this consistently lost region, suggesting that neither of them are targets for the 1p loss. In the second part of the study, microdissected primary carcinomas and distant metastases from the same colorectal cancer patients (n=18) were analyzed, and the same 1p genotype was found in the majority of patients (12/18, 67%). The finding that primary carcinoma cells with metastatic ability usually contain 1p deletions, and that some cases lacking 1p alterations in the primary tumor acquire such changes during growth of a metastatic lesion, supports the notion that 1p loss may be important both early and late in colorectal carcinogenesis, with the apparent exception of local recurrences.

Adenocarcinoma↗
PubMedDate not supplied

Evaluation of breast cancer polyclonality by combined chromosome banding and comparative genomic hybridization analysis.

Cytogenetically unrelated clones have been detected by chromosome banding analysis in many breast carcinomas. Because these karyotypic studies were performed on short-term cultured samples, it may be argued that in vitro selection occurred or that small clones may have arisen during culturing. To address this issue, we analyzed 37 breast carcinomas by G-banding and comparative genomic hybridization (CGH), a fluorescent in situ hybridization--based screening technique that does not require culturing or tumor metaphases. All but two of the 37 karyotypically abnormal cases presented copy number changes by CGH. The picture of genomic alterations revealed by the two techniques overlapped only partly. Sometimes the CGH analysis revealed genomic imbalances that belonged to cell populations not picked up by the cytogenetic analysis and in other cases, especially when the karyotypes had many markers and chromosomes with additional material of unknown origin, CGH gave a more reliable overall picture of the copy number gains and losses. However, besides sometimes revealing cell populations with balanced chromosome aberrations or unbalanced changes that nevertheless remained undetected by CGH, G-banding analysis was essential to understand how the genomic imbalances arose in the many cases in which both techniques detected the same clonal abnormalities. Furthermore, because CGH pictures only imbalances present in a significant proportion of the test sample, the very detection by this technique of imbalances belonging to apparently small, cytogenetically unrelated clones of cells proves that these clones must have been present in vivo. This constitutes compelling evidence that the cytogenetic polyclonality observed after short-term culturing of breast carcinomas is not an artifact.

Breast Neoplasms↗
PubMedDate not supplied

Cytogenetic analysis in the examination of solid tumors in children.

Although pediatric solid tumors are cytogenetically less well characterized than childhood leukemias, an understanding of the role of chromosomal changes in the development of these neoplasms is emerging. The major clinical importance of chromosome analysis today is diagnostic. Especially in small cell round cell tumors of childhood, the unique karyotypic patterns that characterize some of the differential diagnostic entities make it possible to determine with a high degree of certainty which type of cancer the child has. Molecular studies have revealed that almost all retinoblastomas show homozygous loss of function of the RB1 gene in 13q14. At the cytogenetic level, however, aberrations of 13q are seen in less than 25% of retinoblastomas; instead, the presumably progression-related i(6p) and aberrations leading to gain of 1q predominate, each being present in one-third of the tumors. Twenty percent of cytogenetically aberrant Wilms' tumors show structural rearrangements, often deletions, of 11p13 and 11p15, where the WT1 and WT2 genes map. Other frequent changes are trisomy 12 and duplication of 1q. The most common (80%) cytogenetic abnormality in neuroblastoma is loss of distal 1p, a chromosome segment thought to harbor at least two tumor-suppressor genes of importance in tumorigenesis. Double minute chromosomes or homogeneously staining regions are present in one-third of all neuroblastomas and are associated with MYCN amplification. Loss of 1p material or MYCN amplification predicts a poor outcome. The most common (30%) chromosomal aberration in primitive neuroectodermal tumors of the central nervous system is i(17q). The formation of this isochromosome may help inactivate a tumor-suppressor gene located distal to the TP53 locus on 17p. No specific chromosome abnormality has been detected in gliomas, but monosomy 22 and rearrangements leading to loss of 1p and gain of 1q are recurrent. Few hepatoblastomas with chromosomal changes have been reported, but several potential primary aberrations have been described, including +2, +20, and duplication 8q. In Ewing's sarcoma, t(11;22)(q24;q12) is the primary aberration, with trisomy 8 and gain of 1q being frequent secondary changes. Fibrosarcomas in children often carry only numeric aberrations, especially trisomy for chromosomes 11, 20, 17, and 8. Most osteosarcomas are cytogenetically complex, and no specific abnormality has been detected; the single most common change is loss of chromosome 13, which is observed in half the tumors. In contrast, the low-malignancy parosteal osteosarcomas often display supernumerary ring chromosomes as the sole karyotypic deviation. The cytogenetic profiles of rhabdomyosarcomas differ among the various morphologic subtypes.(ABSTRACT TRUNCATED AT 400 WORDS)

Child↗