Biomedical subjects

Hans-Helge Seifert

Publications and source records attributed to Hans-Helge Seifert.

15 recordsLinked to original sources

PubMed2006

In situ detection of global DNA hypomethylation in exfoliative urine cytology of patients with suspected bladder cancer.

Global DNA hypomethylation is a common phenomenon in bladder cancer. Therefore we investigated whether it is possible to detect and assess global DNA hypomethylation in bladder cancer using a specific monoclonal antibody for 5-methyl-cytosine. Cytospins from exfoliative urine cytology specimens of patients with bladder cancer or a history of bladder cancer, control patients with benign urological diseases and of young healthy volunteers were analyzed. Urothelial carcinoma (UC) cells showed various degrees of nuclear destaining indicating global DNA hypomethylation whereas all specimens from healthy volunteers showed granular nuclear staining indicating regular methylation of repeated DNA sequences. Lowest 5-methylcytosine immunostaining scores were observed in carcinoma cells and a statistically significant difference was observed between urothelial cells of healthy controls or patients with benign disease compared to bladder cancer patients (p<0.01, p<0.05, respectively). In UC cases even morphologically normal urothelial cells often displayed evident hypomethylation. Likewise, in patients with a history of UC, but no cystoscopic evidence of recurrence, morphologically non-malignant urothelial cells presented with some degree of demethylation. Our results strongly support the hypothesis of early global demethylation in bladder cancer. Immunocytochemical staining with the 5-methylcytosine antibody allows simultaneous individual assessment of nuclear morphology and methylation status of a given sample.

5-Methylcytosine↗

PubMed2006

Photoselective vaporization of the prostate: subgroup analysis of men with refractory urinary retention.

OBJECTIVES: The purpose of this study was to evaluate the feasibility and efficacy of photoselective vaporization of the prostate (PVP) in patients with refractory urinary retention (RUR) secondary to benign prostate hyperplasia (BPH). METHODS: Perioperative data, postoperative outcomes, and adverse events within 24 months in 70 patients with RUR were compared to 113 men with no urinary retention (NUR) before surgery. RESULTS: Follow-up for the two groups was as follows (RUR vs. NUR at 1, 3, 6, 12, and 24 months): peak urinary flow rate: 16.9 vs. 19.4 ml/s, 16.3 vs. 20.9 ml/s, 17.7 vs. 19.7 ml/s, 18.2 vs. 21 ml/s, and 19.4 vs. 23.3 ml/s; International Prostate Symptom Score: 7.6 vs. 10.7, 7 vs. 7.5, 5.7 vs. 6.2, 5.5 vs. 6.5, and 4.4 vs. 6.5, respectively. Postoperative urinary retention and complication rates were comparable for the two groups. In five patients (2.7%), a reoperation with PVP or transurethral resection of the prostate was necessary. Bladder neck contracture and urethral stricture developed in 0.5% (n=1) and 4.9% (n=9), respectively. CONCLUSION: PVP seems to be a safe and effective surgical tool in patients with RUR caused by prostatic enlargement. The complication rate is comparable to that of patients with NUR before PVP.

Adult↗

PubMed2006

Ureteral obstruction after dextranomer/hyaluronic acid copolymer injection for treatment of secondary vesicoureteral reflux after renal transplantation.

Ureteral obstruction after transurethral injection therapy for primary vesicoureteral reflux is known to occur in less than 1% of cases. We report the first case of a ureteral obstruction after transurethral injection of dextranomer/hyaluronic acid copolymer (Deflux) for the treatment of secondary vesicoureteral reflux after renal transplantation. Loss of transplant function made reimplantation of the ureter necessary. A periureteral phlebitis and moderate foreign body reaction was found histologically, although the patient had received immunosuppressive therapy. Endoscopic therapy of secondary vesicoureteral reflux in patients after renal transplantation is a reasonable minimally invasive treatment option; however, severe complications may occur.

Dextrans↗

PubMed2006

Laparoscopic extended pelvic lymph node dissection for high-risk prostate cancer.

INTRODUCTION: Recently, some controversy has arisen as to whether pelvic lymphadenectomy is still necessary for patients with prostate cancer who are undergoing radical prostatectomy. We prospectively evaluated the results and morbidity of laparoscopic extended pelvic lymph node dissection in patients with high-risk prostate cancer defined as a serum prostate-specific antigen (PSA) level greater than 10 ng/mL or preoperative biopsy Gleason score of 7 or more. TECHNICAL CONSIDERATIONS: In 123 consecutive patients with clinically organ-confined high-risk prostate cancer, laparoscopic extended pelvic lymphadenectomy was performed before laparoscopic radical prostatectomy. The boundaries of the pelvic lymph node dissection were the bifurcation of the common iliac artery superiorly, the node of Cloquet inferiorly, the external iliac vein laterally, and the bladder wall medially. Preparation was done with bipolar forceps and scissors, with meticulous coagulation of all lymphatic tissue. The mean PSA level was 14.8 ng/mL (range 1.5 to 43.4). The mean number of lymph nodes removed was 21 (range 9 to 55). A total of 21 patients (17%) had lymph node metastases. The overall complication rate was 4%. CONCLUSIONS: Laparoscopic extended pelvic lymph node dissection is safe and effective. The results and morbidity are equivalent to those of open surgery, with the advantage of a minimally invasive operative technique.

Feasibility Studies↗

PubMed2005

Photoselective vaporization (PVP) versus transurethral resection of the prostate (TURP): a prospective bi-centre study of perioperative morbidity and early functional outcome.

OBJECTIVES: To compare the early follow-up and perioperative morbidity of photoselective vaporization (PVP) and transurethral resection of the prostate (TURP) in patients (pts.) suffering from lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). MATERIAL AND METHOD: 101 pts. underwent PVP (n = 64) and TURP (n = 37) in a prospective, non-randomized bi-centre trial. Inclusion criteria were identical at both centres. Primary outcome parameters were maximum urinary flow rate (Q(max)), post-void residual volume (V(res)), International Prostate Symptom Score (IPSS). Secondary outcomes included intraoperative surgical parameters and perioperative and post-discharge morbidity. RESULTS: Baseline characteristics of both groups were similar. Operating time was slightly shorter in the TURP group (p = 0.047). During TURP significant more irrigation solution was used (p < 0.001). Decrease of serum haemoglobin (p = 0.027) and serum sodium (p = 0.013) was larger after TURP. Catheter drainage was removed significant earlier after PVP than after TURP (p < 0.001). Outcome of Q(max), and IPSS were similar in both groups within 6 months. The sort of perioperative complications was different in both groups, however overall cumulative perioperative morbidity was comparable (PVP 39.1% versus TURP 43.2.1%; ns). CONCLUSION: PVP provides excellent intraoperative safety, instant tissue removal, and immediate relief from obstructive voiding symptoms, similar to TURP. Early outcomes 6-months after PVP and TURP are comparable.

Aged↗

PubMed2005

Multiple mechanisms downregulate CDKN1C in human bladder cancer.

Expression of the imprinted CDKN1C gene at chromosome 11p15.5 encoding the cell cycle inhibitor p57(KIP2) is disturbed in Beckwith-Wiedemann syndrome and in several human cancers by different mechanisms. Many advanced urothelial cancers (TCC) display downregulation of CDKN1C expression. The responsible mechanisms were investigated in TCC cell lines, with cultured normal urothelial cells (UEC) as controls. CDKN1C mRNA expression was diminished in 12/15 TCC lines and p57(KIP2) protein was decreased accordingly. Because CDKN1C is expressed from the maternal allele only, LOH at 11p15.5 represents one mechanism of downregulation. In 3 cell lines, several polymorphic markers flanking CDKN1C were homozygous compatible with this mechanism. Hypermethylation of the CDKN1C promoter, a reported cause of downregulation in other cancers, was detected by bisulfite sequencing in several cell lines and appeared associated with downregulation in at least one cell line. The methylation inhibitor 5-aza-2'deoxycytidine induced CDKN1C expression in this cell line and others. A third reported mechanism involves a switch of both alleles toward a paternal imprinting pattern, indicated by hypomethylation of a differentially methylated region (DMR) in the imprinting center (IC2). This hypomethylation was detected in most TCC lines, and was associated with re-expression of the non-coding LIT1 RNA and with downregulation of CDKN1C in several. Thus, CDKN1C downregulation in TCC seems to occur by several different mechanisms. This finding and the ability of p57(KIP2) to induce senescence in urothelial cells make CDKN1C a good candidate for a tumor suppressor at 11p in TCC.

Carcinoma, Transitional Cell↗

PubMed2005

Hedgehog signaling in normal urothelial cells and in urothelial carcinoma cell lines.

Constitutive activation of hedgehog signaling, often caused by PTCH1 inactivation and leading to inappropriate activation of GLI target genes, is crucial for the development of several human tumors including basal cell carcinoma of the skin and medulloblastoma. The PTCH1 gene at 9q22 is also considered as a candidate tumor suppressor in transitional cell carcinoma (TCC), of which >50% show LOH in this region. However, only rare mutations have been found in PTCH1. We have therefore investigated GLI-dependent promoter activity and expression of hedgehog pathway components in TCC cell lines and proliferating normal urothelial cells. Normal urothelial cells cultured in serum-free medium, but not TCC lines exhibited low, but significant promoter activity under standard growth conditions. Accordingly, GLI1-3 and PTCH1 mRNAs were expressed at moderate levels, and sonic hedgehog (SHH) mRNA expression was low to undetectable. In co-transfection experiments GLI1 increased promoter activity significantly in one TCC line and further in normal urothelial cells, but less strongly in other TCC lines. Expression patterns of GLI factor mRNAs did not correlate with inducibility. No significant effects of SHH or cyclopamine on proliferation were observed, ruling out autocrine effects. However, SHH induced GLI-dependent promoter activity in normal urothelial cells. Taken together, our data suggest that the hedgehog pathway is weakly active in normal adult urothelial cells and of limited importance in TCC.

Carcinoma, Transitional Cell↗

PubMed2004

Denaturing high-performance liquid chromatography (DHPLC) as a reliable high-throughput prescreening method for aberrant promoter methylation in cancer.

Aberrant promoter hypermethylation of CpG dinucleotides is a frequent and significant mechanism of tumor suppressor gene (TSG) silencing in cancer. As increasing numbers of downregulated putative TSGs are emerging from large-scale expression profiling studies, high-throughput techniques are needed to screen for hypermethylation. DHPLC has been established as a reliable, highly sensitive technique for mutation analysis. In this study, the use of DHPLC as a prescreening method for the identification of CpG methylation was developed by analyzing DNA samples with different, well-characterized methylation patterns of the CDKN2A/p16 promoter. Bisulfite treatment of genomic DNA was followed by PCR-amplification of unmethylated as well as methylated CDKN2A/p16 promoter sequences. PCR products were denatured and renatured, permitting the formation of heteroduplex DNA detectable by DHPLC. Methylation of all CpG-sites results in a single peak (homoduplex) with a shift in retention time, whereas partial methylation can be recognized by additional signals representing diverse heteroduplex structures. After method development, 35 DNA samples from primary bladder and breast carcinomas were analyzed in a blinded fashion, revealing complete or partial methylation of the p16 promoter in eight cases and a heterozygous mutation in one case. In conclusion, DHPLC is a highly sensitive and convenient method for methylation screening.

Breast Neoplasms↗

PubMed2004

Decreased Fas expression in advanced-stage bladder cancer is not related to p53 status.

OBJECTIVES: The Fas-Fas ligand system is an important regulator of apoptosis and is involved in tumor development. Invasive cancers downregulate Fas expression to evade antitumor immune responses. Fas is a transcriptional target of p53, which is often mutated in bladder cancers. Therefore, Fas expression and its relation to p53 mutation was investigated. METHODS: Expression of Fas protein and p53 status was studied by immunohistochemistry in 83 bladder cancer specimens. In addition, mRNA levels for soluble (decoy) and membrane-bound forms of Fas were compared between 10 bladder cancer cell lines and primary uroepithelial cells by quantitative TaqMan polymerase chain reaction. Mutational analysis of the death domain of the Fas gene was performed in all cell lines. RESULTS: Organ-confined tumors maintained specific Fas staining at the cell membrane and often also in the cytoplasm. In higher stage carcinomas, Fas expression became restricted to a smaller fraction of cells or was lacking entirely. The correlation of Fas staining with tumor stage was highly significant but no correlation to tumor grade or survival was found. Furthermore, no statistically significant relationship was observed with either the presence or lack of mutated p53 accumulation. Membrane-bound Fas mRNA was decreased in most, and soluble Fas was increased in all transitional cell carcinoma lines compared with primary uroepithelial cells. No mutations in the death domain were detected. CONCLUSIONS: Fas downregulation occurring in advanced bladder cancer is unrelated to p53 mutations. The results of immunohistochemistry and mRNA studies of soluble and membrane-bound Fas in transitional cell carcinoma lines support the hypothesis of immune evasion in advanced bladder cancer.

Carcinoma, Papillary↗

PubMed2003

Decrease of DNA methyltransferase 1 expression relative to cell proliferation in transitional cell carcinoma.

In many common cancers such as transitional cell carcinoma (TCC), specific genes are hypermethylated, whereas overall DNA methylation is diminished. Genome-wide DNA hypomethylation mostly affects repetitive sequences such as LINE-1 retrotransposons. Methylation of these sequences depends on adequate expression of DNA methyltransferase I (DNMT1) during DNA replication. Therefore, DNMT1 expression relative to proliferation was investigated in TCC cell lines and tissue as well as in renal carcinoma (RCC) cell lines, which also display hypomethylation, as indicated by decreased LINE-1 methylation. Cultured normal uroepithelial cells or normal bladder tissue served as controls. In all tumor cell lines, DNMT1 mRNA as well as protein was decreased relative to the DNA replication factor PCNA, and DNA hypomethylation was present. However, the extents of hypomethylation and DNMT1 downregulation did not correlate. Reporter gene assays showed that the differences in DNMT1 expression between normal and tumor cells were not established at the level of DNMT1 promoter regulation. Diminished DNMT1:PCNA mRNA ratios were also found in 28/45 TCC tissues but did not correlate with the extent of DNA hypomethylation. In addition, expression of the presumed de novo methyltransferases DNMT3A and DNMT3B mRNAs was investigated. DNMT3B overexpression was observed in about half of all high-stage TCC (DNMT3B vs. tumor stage, chi(2): p = 0.03), whereas overexpression of DNMT3A was rarer and less pronounced. Expression of DNMT3A and DNMT3B in most RCC lines was higher than in TCC lines. Our data indicate that DNMT1 expression does not increase adequately with cell proliferation in bladder cancer. This relative downregulation probably contributes to hypomethylation of repetitive DNA but does not determine its extent alone.

Aged↗

PubMed2003

Activities of MAP-kinase pathways in normal uroepithelial cells and urothelial carcinoma cell lines.

It is often assumed that MAPK pathways drive proliferation of normal uroepithelial (UEC) and urothelial carcinoma (TCC) cells. To check this assumption, activities and inducibilities of promoters containing serum-response elements (SRE) or AP-1 binding sites were investigated in cultured UEC and seven TCC lines. Reporter plasmids dependent on SRE or AP-1 sites were highly active in UEC, but significantly less so in TCC lines. Reporter activity in TCC lines could be induced by constitutively active MEKK4 or TPA. Accordingly, phosphorylation of the MAPK pathway components MEK, ERK, and ELK1 was most pronounced in UEC and lower in TCC lines. MAPK-dependent promoter activities and bromodeoxyuridine incorporation decreased in UEC upon withdrawal of growth factors, but less so in TCC lines, in which serum diminution increased apoptosis. Likewise, E2F-dependent promoters responded to growth factors in UEC, but were more serum-independent in the TCC lines, which lack either RB1 or p16(INK4A). MEK inhibitors inhibited BrdU incorporation in UEC more strongly than in TCC lines. Thus, proliferation of normal uroepithelial cells is indeed associated with activation of MAPK pathways. However, autonomous proliferation of TCC lines--unexpectedly--appears much less dependent on MAPK activation and may rather be promoted by defects in cell cycle regulation.

Binding Sites↗

PubMed2002

Tumour class prediction and discovery by microarray-based DNA methylation analysis.

Aberrant DNA methylation of CpG sites is among the earliest and most frequent alterations in cancer. Several studies suggest that aberrant methylation occurs in a tumour type-specific manner. However, large-scale analysis of candidate genes has so far been hampered by the lack of high throughput assays for methylation detection. We have developed the first microarray-based technique which allows genome-wide assessment of selected CpG dinucleotides as well as quantification of methylation at each site. Several hundred CpG sites were screened in 76 samples from four different human tumour types and corresponding healthy controls. Discriminative CpG dinucleotides were identified for different tissue type distinctions and used to predict the tumour class of as yet unknown samples with high accuracy using machine learning techniques. Some CpG dinucleotides correlate with progression to malignancy, whereas others are methylated in a tissue-specific manner independent of malignancy. Our results demonstrate that genome-wide analysis of methylation patterns combined with supervised and unsupervised machine learning techniques constitute a powerful novel tool to classify human cancers.

Algorithms↗

PubMed2002

Genomewide DNA hypomethylation is associated with alterations on chromosome 8 in prostate carcinoma.

To elucidate the relationship between genomewide DNA hypomethylation and chromosome instability, 55 prostate carcinoma specimens were analyzed for extent of hypomethylation by Southern blot analysis of LINE-1 sequence methylation and for loss or gain of chromosomal material by comparative genomic hybridization. Seventeen (31%) tumors showed strong hypomethylation of DNA, whereas four (7%) displayed slight hypomethylation and the rest of the tumors normal-level methylation. Chromosomal aberrations were observed in 34 carcinomas. The most frequent chromosomal alterations were loss of 13q in 18 cases and aberrations in 8p (loss) or 8q (gain) in 16 cases. The presence of chromosomal loss or gain was significantly associated with the presence of strong hypomethylation. A striking correlation (P = 0.00001) was observed between aberrations on chromosome 8 and hypomethylation, whereas no association was seen between DNA hypomethylation and loss of 13q. The association between DNA hypomethylation and the presence of metastases was statistically significant (P = 0.044), and both chromosomal alterations and DNA hypomethylation tended to be more frequent in higher-stage tumors. In conclusion, the data indicate that hypomethylation is associated with chromosomal instability in prostate cancer. Specifically, a surprisingly strong association between alterations on chromosome 8 and genomewide hypomethylation was found. This association suggests that DNA hypomethylation and alterations in chromosome 8 may be mechanistically linked to each other in prostate carcinoma.

Aged↗

PubMed2002

Activity of E2F-dependent promoters in bladder carcinoma cells and their use for tumour-specific targeting of p53-induced apoptosis.

Inactivation of P53 and RB functions are crucial changes in bladder cancer (TCC). High-level re-expression of P53 elicits apoptosis in TCC cell lines, but also--as shown here--in normal uroepithelial cells. Compromised RB function is thought to cause increased activity of E2F-dependent promoters in carcinoma cells. Indeed, several, but not all E2F-dependent promoters were stronger in TCC lines than in normal cells, with the highest activities in cell lines lacking RB rather than p16INK4A. Re-expression of p53 from an E2F-dependent promoter suppressed clone formation and induced apoptosis in TCC lines as efficiently as expression from the stronger RSV-LTR or LINE-1 promoters. In normal cells, p53 expression from an E2F-dependent promoter was tolerated, whereas expression from both stronger promoters was lethal. Thus, specific E2F-dependent promoters allow adjustment of p53 expression to selectively induce apoptosis in TCC vs. normal uroepithelial cells. This approach could be useful in targeting apoptosis to TCC and other carcinomas lacking p53 and RB function.

Apoptosis↗

PubMedDate not supplied

Detection of circulating prostate cells during radical prostatectomy by standardized PSMA RT-PCR: association with positive lymph nodes and high malignant grade.

BACKGROUND: The purpose of this study was to establish a quantitative standardized RT-PCR for the detection of Prostate Specific Membrane Antigen (PSMA)-expressing circulating cells and to evaluate clinical relevance in patients undergoing radical retropubic prostatectomy (RRP) for clinically localized prostate cancer (PCa). MATERIALS AND METHODS: An external standard molecule (PSMA MIMIC) was constructed for standardization of PSMA RT-PCR reactions. It has the same sequence as endogenous PSMA, except for a central 85 bp deletion, allowing the amplification of both targets simultaneously with nearly the same amplification characteristics as in a nested PCR. PSMA RT-PCR was performed from peripheral blood samples of 73 patients with clinically localized PCa, 4 with metastatic PCa, 27 with benign prostatic hyperplasia (BPH) and 27 controls. Pre, intra- and postoperative blood samples were tested for circulating PSMA expressing cells in 54 out of 73 patients with clinically localized PCa. We also tested intraoperative blood samples of 19 BPH patients treated by transurethral or open surgery. RESULTS: Endogenous PSMA signals from PCa patients varied between 850 and 9900 transcript molecules, corresponding to 2-20 PSMA-expressing cells/ml blood. Standardized RT-PCR using the PSMA MIMIC molecule revealed a significant decrease of "false-positives" in cancer-free controls (p = 0.004). Controls could clearly be distinguished from prostate cancer patients based on PSMA PCR positivity (p = 0.003). Thirty-two % of patients with localized prostate cancer, 11% of BPH patients and 7% of healthy controls were positive in standardized assays compared to 48%, 30% and 27% without PSMA MIMIC, respectively. Preoperatively, a correlation with tumor stage (p = 0.030), grade (p = 0.035) and Gleason Score (p = 0.03) could be demonstrated in clinically localized PCa patients. Dissemination of prostate cells during surgery occurred in 32% of the RRPs and 21% of BPH patients. Positive PCR signals from intraoperative blood samples correlated with positive lymph node status (p = 0.007) and tumor grade (p = 0.005). Postoperative positive results correlated with grade (p = 0.012) and Gleason Score (p = 0.035). CONCLUSION: Counseling the patient with clinically localized prostate cancer can be challenging. Surgery may be, in retrospect, inappropriate in a number of patients due to preoperative understaging. This newly constructed external standard allows quantitative detection of circulating prostate cells, and therefore may open new perspectives for PSMA RT-PCR techniques as diagnostic assays and tools for post-therapeutic follow-up.

Antigens, Surface↗