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Biomedical subjects

S Heim

Publications and source records attributed to S Heim.

At least 19 recordsLinked to original sources
PubMed1999

Dual function of the selenoprotein PHGPx during sperm maturation.

The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) changes its physical characteristics and biological functions during sperm maturation. PHGPx exists as a soluble peroxidase in spermatids but persists in mature spermatozoa as an enzymatically inactive, oxidatively cross-linked, insoluble protein. In the midpiece of mature spermatozoa, PHGPx protein represents at least 50 percent of the capsule material that embeds the helix of mitochondria. The role of PHGPx as a structural protein may explain the mechanical instability of the mitochondrial midpiece that is observed in selenium deficiency.

Animals↗
PubMed1999

Combined RxFISH/G-banding allows refined karyotyping of solid tumors.

Chromosome banding analysis of solid tumors often yields incomplete karyotypes because of the complex rearrangements encountered. The addition of fluorescence in situ hybridization (FISH) methods has helped improve the accuracy of solid tumor cytogenetics, but the absence of screening qualities from standard FISH approaches has proved a severe limitation. We describe the cytogenetic analysis of ten solid tumors using G-banding followed by cross-species color banding (RxFISH), a FISH-based screening technique giving a chromosome-specific banding pattern based on the genomic homologies between humans and gibbons. The addition of RxFISH analysis in all cases led to the identification of previously unidentified intra- as well as interchromosomal rearrangements, thus giving a much more certain and detailed karyotype. In two gastric stromal sarcomas, a tumor type for which no cytogenetic data were hitherto available, numerical chromosomal aberrations dominated, but one of the tumors also carried an unbalanced 7;17-translocation with the same breakpoint in chromosome 17 as that seen in endometrial stromal sarcomas.

Chromosome Aberrations↗
PubMed1999

Karyotypic findings in tumors of the vulva and vagina.

Neoplasms of the vulva and vagina together account for less than 5% of all female genital tract cancers, and very few cases have been analyzed using chromosome banding techniques. We report the karyotypic findings in a consecutive series of ten tumors of the vulva and vagina; in addition to five squamous cell carcinomas of the vulva, we present the first cytogenetic analysis of two malignant melanomas and a Paget disease of the vulva, as well as an adenocarcinoma and a squamous cell hyperplasia of the vagina. Whereas no clonal karyotypic changes were found in the squamous cell hyperplasia of the vagina, the remaining nine malignant tumors showed clonal chromosome abnormalities. An inverse correlation was found between the degree of histologic differentiation and karyotypic complexity in the squamous cell carcinomas of the vulva. The malignant melanomas had chromosomal aberrations that have previously been described in malignant melanomas occurring elsewhere, but were less karyotypically complex. Cytogenetically unrelated clones were detected in the Paget disease of the vulva but not in any of the other tumors; this finding is consonant with the interpretation that at least a proportion of Paget disease of the vulva arises multicentrically within the epidermis from pluripotent stem cells.

Adenocarcinoma↗
PubMed1999

Karyotypic evolution in breast carcinomas with i(1)(q10) and der(1;16)(q10;p10) as the primary chromosome abnormality.

The pattern of clonal karyotypic evolution in breast carcinomas carrying an i(1q) or a der(1;16)(q10;p10) as the primary chromosome abnormality was assessed in a series of 42 tumors, including 8 described here for the first time, with either or both (3 tumors) of them defining cytogenetic features. Evidence of clonal evolution was seen in somewhat more than half of all cases in both subgroups. The secondarily acquired aberrations appeared to be nonrandom in distribution. This was especially so for structural rearrangements of 11q leading to loss of material from this arm, which were clearly more common in both subgroups than in karyotypically abnormal breast carcinomas in general. Other deviations from random were less certain but seemed to include the frequent occurrence of +20 in tumors with i(1q) and +7 in tumors with der(1;16)(q10;p10). That differences were observed between i(1q) carcinomas and der(1;16)(q10;p10) carcinomas with regard to their patterns of clonal evolution hints that the pathogenetic effect of the primary change in these two situations may be more than the mere gain of an extra copy of 1q.

Breast Neoplasms↗
PubMed1999

Development of an automated microbial sensor system.

An automated whole cell biosensor system was developed by integration of immobilized microbial cells in a flow-through system with screen-printed flow-through electrodes as detectors. The detectors used were thick-film Pt-electrodes in a 3-electrode configuration constructed as sandwich flow-through cells with a volume of about 36 microliters polarized at -900 mV. The measuring principle was the determination of oxygen consumption due to the microbial metabolism. Fructose was used as model analyte. The microorganisms were immobilized on cellulose-acetate membranes and integrated into a newly created reaction chamber (membrane reactor). The microbial cells used were Rhodococcus erythropolis and Issatchenkia orientalis known to be suitable for the determination of biological oxygen demand.

Biosensing Techniques↗
PubMed1999

Cytogenetic monoclonality in multifocal uroepithelial carcinomas: evidence of intraluminal tumour seeding.

Twenty-one multifocal urinary tract transitional cell carcinomas, mostly bladder tumours, from a total of six patients were processed for cytogenetic analysis after short-term culturing of the tumour cells. Karyotypically related, often identical, cytogenetically complex clones were found in all informative tumours from each case, including the recurrent tumours. Rearrangement of chromosome 9, leading to loss of material from the short and/or the long arm, was seen in all cases, indicating that this is an early, pathogenetically important event in transitional cell carcinogenesis. The presence of related clones with great karyotypic similarity in anatomically distinct tumours from the same bladder indicates that multifocal uroepithelial tumours have a monoclonal origin and arise via intraluminal seeding of viable cancer cells shed from the original tumour. Later lesions may develop also from cells shed from the so called second primary tumours. The relatively complex karyotypes seen in all lesions from most cases argue that the seeding of tumour cells is a late event that succeeds the acquisition by them of multiple secondary genetic abnormalities.

Aged↗
PubMed1999

Cross-species color banding characterization of chromosomal rearrangements in leukemias with incomplete G-band karyotypes.

Karyotype analysis has depended on chromosome banding techniques since their introduction in about 1970, and the information thus obtained is indispensable for the clinical management of patients with hematologic malignancies. Sometimes, however, chromosomal rearrangements involve segments too small, too similarly banded, or too complex to be described adequately or even to be detected by G-banding. Cross-species color banding is a new FISH-based screening technique that enables the generation of a specific color banding pattern for each human chromosome based on the genomic homologies between man and various species of apes. We report the first application of cross-species color banding (RxFISH) to characterize the chromosomal rearrangements of 10 leukemia samples the G-band karyotypes of which were incomplete. The combination of G-banding and RxFISH in every case yielded additional information beyond that obtained by either technique used alone, determining the identity of even the most complex, inter- as well as intrachromosomal, rearrangements. Genes Chromosomes Cancer 26:13-19, 1999.

Adolescent↗
PubMed1998

Cytogenetic analysis of colorectal adenomas: karyotypic comparisons of synchronous tumors.

The phenotypic progression of colorectal tumors is driven by their step-by-step acquisition of genomic alterations. These pathogenetically important mutations are at the same time markers of tumor clonality. The aim of this study was to describe the clonal relation among synchronous colorectal adenomas. Twenty-four colorectal adenomas from 11 patients were subjected to chromosome banding analysis. Clonal chromosome abnormalities were found in 20 tumors. Recurrent structural rearrangements involved chromosomes 1, 13, 17, and 18. The most common numerical changes were gain of chromosomes 7, 13, 20, and 3 and loss of chromosome 18. Eight adenomas had subclones as evidence of clonal evolution. Similar clones in separate polyps were seen in tumors from 6 patients; these adenomas were always located in the same part of the large bowel. In 2 patients, both with one rectal adenoma and one adenoma in the colon, no karyotypic similarity between the lesions was found. Our findings indicate that whereas close, but macroscopically distinct, synchronous colorectal adenomas usually have a common pathway of progression, perhaps even the same clonal origin, large bowel adenomas at a considerable distance from one another exhibit karyotypic differences, indicating that they arise independently.

Adenoma↗
PubMed1998

Cytogenetic findings in invasive breast carcinomas with prognostically favourable histology: a less complex karyotypic pattern?

Seventeen invasive primary breast carcinomas of histological types usually considered to be prognostically favourable (2 medullary, 3 papillary, 3 tubular, and 9 mucinous carcinomas) were analysed as part of an ongoing study of the cytogenetics of breast cancer. Thirteen of the tumours (7 mucinous, 2 medullary, 2 papillary, and 2 tubular carcinomas) showed clonal chromosome aberrations. Trisomy 7 and i(1q) were present as sole and recurrent aberrations in the mucinous tumours. The 2 tubular carcinomas and I papillary carcinoma had simple numerical changes only, whereas the second papillary tumour had a balanced translocation as the sole anomaly. Both medullary carcinomas had chromosome numbers in the triploid range, with clones displaying structural and numerical changes. Our data, especially when collated with information on previously published cases of mucinous, papillary, tubular, and medullary breast carcinomas, show that the former 3 histological types, in keeping with their recognised prognostic advantage, appear to exhibit relatively simple karyotypic changes, i.e., numerical aberrations, balanced translocations, and near-diploid chromosome numbers. Medullary carcinomas on the other hand, appear to have more complex karyotypes, similar to those described for the more common ductal and lobular subtypes of breast carcinoma.

Adenocarcinoma, Mucinous↗
PubMed1998

[Molecular genetic diagnosis of leukemias and lymphomas].

Leukemias and lymphomas are genetically characterized by pathogenetically important, disease-specific mutations in the malignant cells. Many of the mutations arise through balanced chromosomal rearrangements, often translocations, that fuse oncogenes with other gene loci. In some instances, this leads to the formation of a qualitatively new hybrid gene encoding a leukemogenic or lymphomogenic protein product, whereas on other occasions the result is deregulation of an otherwise normal gene. The demonstration of such gene rearrangements is of both diagnostic and prognostic value and hence serves as an important supplement to the more traditional phenotype-based investigative techniques. All available methods to detect neoplasia-specific, acquired mutations have both advantages and disadvantages, depending partly on the level of resolution at which they operate (chromosomes, nucleic acids, proteins), but also on the specific characteristics of each individual technique. Ideally, the initial genetic diagnosis of a given tumor should be reached by means of an open-framed screening technique, whereas less labour-intensive, specific techniques may be used during the subsequent follow-up of the patient. The most reliable and complete information is always obtained by combining cytogenetic, molecular cytogenetic, and strictly molecular genetic investigations. However, such an approach may be too cumbersome and expensive to be taken routinely.

B-Lymphocytes↗
PubMed1998

Chromosomal abnormalities in two bladder carcinomas with secondary squamous cell differentiation.

Two secondary squamous cell carcinomas of the bladder (i.e., tumors that originated from primary transitional cell carcinomas) were examined cytogenetically. Both tumors showed complex karyotypes with many of the same aberrations that have formerly been described in transitional cell carcinomas. Monosomy 9, trisomy 7, and rearrangements of chromosomes 3, 8, 10, 13, and 17 were common to both tumors. Among other changes that have been implicated in bladder carcinogenesis, an isochromosome for 5p was seen in one tumor and loss of 11p material in the other. Our findings indicate that secondary squamous cell carcinomas of the bladder are karyotypically indistinguishable from advanced transitional cell carcinomas of the same organ. The putative genetic changes that steer the differentiation of the neoplastic epithelium in the direction of squamous cells thus remain unknown.

Aged↗
PubMed1998

Thiol:fumarate reductase (Tfr) from Methanobacterium thermoautotrophicum--identification of the catalytic sites for fumarate reduction and thiol oxidation.

Most methanogenic Archaea contain an unusual cytoplasmic fumarate reductase which catalyzes the reduction of fumarate with coenzyme M (CoM-S-H) and coenzyme B (CoB-S-H) as electron donors forming succinate and CoM-S-S-CoB as products. We report here on the purification and characterization of this thiol:fumarate reductase (Tfr) from Methanobacterium thermoautotrophicum (strain Marburg). The purified enzyme, which was composed of two different subunits with apparent molecular masses of 58 kDa (TfrA) and 50 kDa (TfrB), was found to catalyze the following reactions: (a) the reduction of fumarate with CoM-S-H and CoB-S-H (150 U/mg); (b) the reduction of fumarate with reduced benzyl viologen (620 U/mg); (c) the oxidation of CoM-S-H and CoB-S-H to CoM-S-S-CoB with methylene blue (95 U/mg); and (d) the reduction of CoM-S-S-CoB with reduced benzyl viologen (250 U/mg). The flavoprotein contained 12 mol non-heme iron and approximately the same amount of acid-labile sulfur/mol heterodimer. The genes encoding TfrA and TfrB were cloned and sequenced. Sequence comparisons with fumarate reductases and succinate dehydrogenases from Bacteria and Eucarya and with heterodisulfide reductases from M. thermoautotrophicum and Methanosarcina barkeri revealed that TfrA harbors FAD-binding motifs and the catalytic site for fumarate reduction and that TfrB harbors one [2Fe-2S] cluster and two [4Fe-4S] clusters and the catalytic site for CoM-S-H and CoB-S-H oxidation.

Amino Acid Sequence↗
PubMed1998

Allelic imbalance and cytogenetic deletion of 1p in colorectal adenomas: a target region identified between DIS199 and DIS234.

Both cytogenetic and molecular genetic analyses have shown that many colorectal adenomas carry an acquired deletion distally in the short arm of one chromosome 1, but the two methods have never been brought to bear on the same tumors. The major part of this study was the analysis of 53 previously short-term cultured and karyotyped colorectal adenomas for allelic imbalance at eight microsatellite loci in 1p. Allelic imbalances were detected in seven of the 12 adenomas that had cytogenetically visible abnormalities of chromosome 1, as well as in four adenomas that either had a normal karyotype (one case) or had clonal chromosome abnormalities that did not seem to involve chromosome 1 (three cases); i.e., 30% of the adenomas had abnormalities involving 1p by the combined approach. A minimal region of overlap seemed to map to between DIS199 and DIS234, suggesting that this is a relevant target region. This genomic area contains the human homologue of the tumor modifier gene Mom1 (1p35-36.1), which, in mice, modifies the number of intestinal tumors in multiple intestinal neoplasia (Min)-mutated animals. To evaluate whether the imbalances corresponded to interstitial deletions of 1p material, we performed fluorescence in situ hybridization with a pericentromeric probe (15 adenomas) and a telomeric probe (6 adenomas) on uncultured cells from the 16 adenomas with chromosome 1 abnormalities. Except for three adenomas that had already been shown by banding analysis to have a trisomic pattern, two centromere 1 signals were invariably found. In the cases hybridized with the 1p-telomeric probe, we found the same frequencies of telomeric and centromeric signals, in agreement with the interpretation that the deletions were interstitial. One of the 53 adenomas had genomic instability, seen as new alleles at five of eight microsatellite loci. A comparison of the genetic findings with clinicopathologic data indicated that adenomas in the rectum have 1p abnormalities more often than do adenomas of the sigmoid colon, and that adenomas with 1p changes are larger than adenomas without abnormalities of chromosome 1.

Adenoma↗
PubMed1998

Chromosome banding analysis of gynecomastias and breast carcinomas in men.

Male breast cancer is 100 times less frequent than its female counterpart and accounts for less than 1% of all cancers in men. Although men with breast cancer also often have gynecomastia, it is still unknown whether gynecomastia per se predisposes the male breast to malignant disease. We describe the cytogenetic analysis of three gynecomastias and four breast cancers in men. No chromosome abnormalities were detected in two cases of gynecomastia, with no other concomitant breast disease. The third gynecomastia sample, taken from a site where a breast carcinoma had previously been removed, had a t(2;11)(p24;p13) as the sole chromosome change; this is the first time that an abnormal karyotype has been described in gynecomastia. All four cancers had clonal chromosome abnormalities. Several cytogenetically unrelated clones were found in the breast tumor and in a metastasis from case 1. In the carcinoma of case 2, a single abnormal clone was found, characterized by loss of the Y chromosome, monosomy 17, and a deletion of the long arm of chromosome 18. In the carcinoma of case 3, a clone with loss of the Y chromosome as the sole change dominated, accompanied by the gain of an X chromosome in a subclone. In the lymph node metastasis examined from case 4, a single clone carrying trisomies for chromosomes 5 and 16 was detected. Our findings, especially when collated with data on the six karyotypically abnormal breast carcinomas in men described previously, indicate that gain of the X chromosome, gain of chromosome 5, loss of the Y chromosome, loss of chromosome 17, and del(18)(q21) are nonrandom abnormalities in male breast carcinomas.

Adult↗
PubMed1998

Nonrandom numerical chromosome abnormalities in basal cell carcinomas.

Clonal chromosome abnormalities were found in 22 of 23 short-term cultured basal cell carcinomas (BCC) of the skin. The karyotypic abnormalities were nonrandom and in several cases included evidence of clonal evolution. Especially in cultures showing an epithelial growth pattern, simple numerical changes, most commonly +18, +9, +20, +7, and +5, predominated and presumably constitute pathogenetically important aberrations present in the neoplastic parenchyma. Also, several structural rearrangements of chromosome arm 9q were seen, which may be of particular interest against the background that a gene for familial BCC (Gorlin syndrome), the PTCH gene, maps to this region. Finally, most of the clonal aberrations detected in predominantly fibroblast-like cultures are likely to reflect changes acquired by cells of the tumor stroma, which raises the question whether mutations also of this tumor component may play a pathogenetic role in BCC development.

Adult↗
PubMed1998

Translocation (3;3)(p14;q29) as the primary chromosome abnormality in a peritoneal mesothelioma.

Mesothelioma is a relatively rare malignant neoplasm arising from the serosal lining of the pleural, peritoneal, and pericardial cavities. Mesotheliomas are known to be associated with asbestos exposure. The karyotypes of these tumors have mostly been so complex as to preclude the identification of primary chromosome abnormalities. We present the cytogenetic analysis of two macroscopically distinct abdominal tumors, both diagnosed as peritoneal mesothelioma, occurring in a woman with a history of heavy asbestos exposure. Both tumors contained the same three karyotypically abnormal but cytogenetically related clones, with a balanced t(3;3)(p14;q29) as the primary chromosomal change. The fact that several chromosome abnormalities were common to both tumors strongly indicates that they arose through intraperitoneal spreading of a single neoplastic process; that is, they were not pathogenetically independent lesions. Our findings, taken together with previously published cytogenetic data on peritoneal mesotheliomas, indicate that a proportion of these tumors may be characterized by simple, balanced chromosomal rearrangements. At least a subset of peritoneal mesotheliomas arises through the same pathogenetic mechanisms that are involved in the pleural forms of this disease.

Aged↗
PubMed1998

Cytogenetic heterogeneity in a second primary radiation-induced bladder carcinoma: ten karyotypically unrelated clones.

Cytogenetic analysis of a transitional cell carcinoma (TCC) of the bladder, the tumor having developed 32 years after the patient received pelvic irradiation and interstitial radium implantation for an endometrial carcinoma, revealed the presence of 10 cytogenetically abnormal, unrelated clones. Although the tumor was poorly differentiated, all clones were pseudo- or near-diploid with rather simple balanced or unbalanced structural rearrangements or both. The chromosomes involved in structural changes more than once were chromosomes 8, 9, and 11, which were rearranged in three clones, and chromosomes 3 and 17, both rearranged in two clones. No previous TCC of the bladder with cytogenetically unrelated clones has been reported, nor has any such radiation-induced tumor with chromosomal abnormalities been described. The distinct karyotypic and clonal pattern of the case presented here is probably indicative of a carcinogenic field effect due to the previous pelvic irradiation. Postradiation bladder carcinomas thus seem to be distinct cytogenetically in addition to their known unique etiological and clinical features.

Aged↗