Biomedical subjects

Bettina Kulle

Publications and source records attributed to Bettina Kulle.

15 recordsLinked to original sources

PubMed2006

Topoisomerase II beta expression level correlates with doxorubicin-induced apoptosis in peripheral blood cells.

Anthracyclines are widely used in oncology. Both the response and side-effects of anthracyclines are individually variable, but determinants or predictive markers of this variability are not available. We investigated the variability in the expression of the anthracycline targets topoisomerases II (topo II) alpha and beta and its significance for the apoptotic response following exposure to the anthracycline doxorubicin. Only topo II beta protein expression was detected in peripheral blood cells. Usually considered a constitutively expressed protein, topo II beta varied 3-, 18-, and 16-fold on the mRNA, protein and activity levels, respectively, among the volunteers tested. In addition, the expression of topo II beta was modified by several mitogens, suggesting a role in the regulation of cell cycle. Strikingly, topo II beta activity correlated statistically significantly with the apoptotic response in peripheral blood leukocytes exposed to 1 microM doxorubicin. A longitudinal study in a subset of study subjects demonstrated that 30% of the topo II expression variability may be inherited. However, resequencing of the TOP2B gene in 48 unrelated individuals revealed only 8 gene variants, none of them with obvious effects on the expression or protein sequence of topo II beta. Taken together, the apoptotic response to doxorubicin in peripheral blood cells may be mediated by topo II beta. The expression level of topo II beta is intra- and inter-individually variable, and may in part determine the apoptotic response to doxorubicin and other anthracyclines.

Antibiotics, Antineoplastic↗

PubMed2006

Lymph node status and TS gene expression are prognostic markers in stage II/III rectal cancer after neoadjuvant fluorouracil-based chemoradiotherapy.

PURPOSE: According to the CAO/ARO/AIO-94 trial of the German Rectal Cancer Study Group, preoperative combined fluorouracil (FU) -based long-term chemoradiotherapy (CT/RT) is recommended for patients with International Union Against Cancer (UICC) stage II/III rectal cancer. However, despite the local benefit of neoadjuvant treatment, the overall prognostic value remains uncertain in comparison with adjuvant CT/RT. Furthermore, the prognostic value of molecular biomarkers, such as thymidylate synthase (TS), thymidine phosphorylase (TP), and dihydropyrimidine dehydrogenase (DPD), all of which are involved in the FU metabolism, is unknown in neoadjuvant settings. We assessed the impact of standardized preoperative CT/RT and intratumoral TS, TP, and DPD levels on patient outcome. PATIENTS AND METHODS: Forty patients with rectal cancer pretherapeutic UICC stage II/III, receiving preoperative FU-based CT/RT (CAO/ARO/AIO-94 trial) followed by standardized surgery, including total mesorectal excision, were investigated. Downsizing, downstaging, tumor regression, as well as TS, TP, and DPD gene expression of post-treatment surgical specimens were correlated with disease-free survival (DFS) and overall survival (OS). RESULTS: Significant downsizing (P < .001) and downstaging (P = .001) were achieved with preoperative CT/RT. During a median follow-up of 49 months (95% CI, 43 to 58 months), the cancer recurrence rate was 28.2%. DFS and OS were significantly increased in patients with downstaging (P < .001 and P = .003, respectively), compared with patients without downstaging. All patients who developed cancer recurrence had a persistent positive lymph node status after preoperative CT/RT (P < .001) and a significantly higher TS gene expression (P = .035) compared with those patients without recurrence. CONCLUSION: Persistent positive lymph node status and high intratumoral TS expression after preoperative CT/RT are predictive of an unfavorable prognosis in rectal cancer UICC stage II/III.

Adult↗

PubMed2006

BDNF gene variants and brain morphology in schizophrenia.

The objective was to investigate putative associations between brain-derived neurotrophic factor gene (BDNF) polymorphisms and brain morphology in patients with schizophrenia and healthy control subjects. Four BDNF polymorphisms were genotyped and analyzed versus 39 brain volume measures in 96 patients with schizophrenia or schizoaffective disorder and 104 healthy subjects. In all subjects, quantitative data on segmented gray, white, and cerebrospinal fluid (CSF) tissue class volumes of total brain and major cerebral lobes including ventricular CSF were obtained using magnetic resonance imaging (MRI). In a randomly selected subset of this population (n = 101-122), MR volumes from cerebellar tonsil, hemispheres, and vermis subregions, striatal structures, hippocampus, and corpus callosum were also measured. The BDNF 11757 G/C polymorphism was highly significantly associated with frontal gray matter volume variation in patients alone and in patients and control subjects combined. In patients only, the 270 C/T polymorphism was associated with total caudate volume. Significant associations were demonstrated between the BDNF 11757 G/C and Val66Met polymorphisms and a global haplotype estimate of four BDNF polymorphisms and the posterior superior cerebellar vermis volume in the controls as well as in the combined group, but not in the patients. The 11757 G/C polymorphism was associated with cerebellar hemisphere white and gray matter volumes in the combined group. The BDNF -633 T/A polymorphism was associated with gray matter of the putamen in the controls. Trends for associations between several polymorphisms/haplotype estimates and MRI volumes were found. BDNF gene variation may influence brain morphology. The effects may be different in patients with schizophrenia and healthy subjects.

Adult↗

PubMed2006

Brain-derived neurotrophic factor gene (BDNF) variants and schizophrenia: an association study.

Polymorphisms in the brain-derived neurotrophic factor (BDNF) gene have been suggested to be associated with schizophrenia. In a replication attempt, Swedish patients with schizophrenia (n=187) and control subjects (n=275) were assessed for four BDNF gene polymorphisms. There were no significantly different allele, genotype or haplotype frequencies between cases or controls. Neither were there any differences when schizophrenic patients were sub-divided with regard to a number of different clinical variables, although a small group of psychotic patients with prominent affective features displayed higher frequencies of the less common alleles of the Val66Met and 11757 G/C polymorphisms compared to controls. The present Swedish results do not verify previous associations between putative functional BDNF gene polymorphisms and schizophrenia. However, when combined with previous studies meta-analyses indicated that the BDNF 270 T-allele and the Val66Met homozygous state were associated with the disorder. Thus, the BDNF gene may confer susceptibility to schizophrenia. Additional studies are warranted to shed further light on this possibility.

Adult↗

PubMed2006

Prognostic value of histologic tumor regression, thymidylate synthase, thymidine phosphorylase, and dihydropyrimidine dehydrogenase in rectal cancer UICC Stage II/III after neoadjuvant chemoradiotherapy.

Histologic tumor regression (TR) in rectal cancer after preoperative chemoradiotherapy (CT/RT) may be useful as a surrogate end point for early treatment efficacy, but little is known about its prognostic value. The aim of this follow-up study was to evaluate whether TR is able to predict prognosis in rectal cancer patients. Furthermore, the prognostic value of thymidylate synthase (TS)-gene, thymidine phosphorylase (TP)-gene, and dihydropyrimidine dehydrogenase (DPD)-gene expression after neoadjuvant CT/RT was determined. Forty patients with rectal cancer cUICC stage II/III, receiving preoperative 5-fluorouracil (5-FU) based CT/RT were studied for therapy-induced TR and categorized as "responders" or "nonresponders" according to their TR-grade. Posttherapeutical TS-gene, TP-gene, and DPD-gene expression on surgical resection specimens was quantified by TaqMan real-time PCR after microdissection. During a median follow-up of 58 months, cancer recurrence occurred in 28%. A significant correlation was seen between disease-free survival and lymph node status (P<0.001). All patients, who developed cancer recurrence had a posttherapeutical positive lymph node status. The majority of patients with cancer recurrence were "responders" (91%) after CT/RT. There was a significant correlation between posttherapeutical TS-gene expression and cancer recurrence within the subgroup of "responders." TS-gene expression was significantly higher in patients with cancer recurrence than in those, who are disease-free up to date (P=0.028). In conclusion, lymph node status remains the most important prognostic marker in rectal cancer patients, whereas posttreatment TR by itself has no prognostic significance. Furthermore, measurement of posttherapeutical TS-gene expression may help to identify patients at higher risk for cancer recurrence.

Antimetabolites, Antineoplastic↗

PubMed2006

Distinct chromosomal profiles in metastasizing and non-metastasizing colorectal carcinomas.

BACKGROUND: The prognosis of colorectal cancer patients is to a considerable extent determined by the metastatic potency of the primary tumor. However, despite the fact that liver metastases are the leading cause of death for cancer patients, the molecular basis still remains poorly understood and independent prognostic markers have not been established. MATERIALS AND METHODS: Comparative genomic hybridization (CGH) was used to screen colorectal carcinomas without distant metastases (n=18) and carcinomas synchronously metastatic to the liver (n=18). We aimed to detect distinct chromosomal aberrations indicating a metastatic phenotype. RESULTS AND DISCUSSION: Metastatic tumors exhibited a significantly (P=0.03) higher ANCA value (13.8) if compared with non-metastatic cancers (10.0). Furthermore, we observed that losses of chromosomal regions 1p32-ter and 9q33-ter were present at much higher frequencies in metastatic than in non-metastatic cancers, respectively (P=0.02 and 0.04). CONCLUSION: These data indicate that metastatic tumors may be separated from non-metastatic colorectal cancers based on their genomic profile.

Aged↗

PubMed2005

Surrogate phenotype definition for alcohol use disorders: a genome-wide search for linkage and association.

For the identification of susceptibility loci in complex diseases the choice of the target phenotype is very important. We compared results of genome-wide searches for linkage or for association related to three phenotypes for alcohol use disorder. These are a behavioral score BQ, based on a 12-item questionnaire about drinking behavior and the subject's report of drinking-related health problems, and ERP pattern and ERP magnitude, both derived from the eyes closed resting ERP measures to quantify brain activity. Overall, we were able to identify 11 candidate regions for linkage. Only two regions were found to be related to both BQ and one of the ERP phenotypes. The genome-wide search for association using single-nucleotide polymorphisms did not yield interesting leads.

Alcohol-Related Disorders↗

PubMed2005

NAD(P)H oxidase and multidrug resistance protein genetic polymorphisms are associated with doxorubicin-induced cardiotoxicity.

BACKGROUND: A significant number of patients treated with anthracyclines develop cardiotoxicity (anthracycline-induced cardiotoxicity [ACT]), mainly presenting as arrhythmias (acute ACT) or congestive heart failure (chronic ACT). There are no data on pharmacogenomic predictors of ACT. METHODS AND RESULTS: We genotyped participants of the German non-Hodgkin lymphoma study (NHL-B) who were followed up for the development of heart failure for a median of >3 years. Single-nucleotide polymorphisms (SNPs) were selected from 82 genes with conceivable relevance to ACT. Of 1697 patients, 55 developed acute and 54 developed chronic ACT (cumulative incidence of either form, 3.2%). We detected 5 significant associations with polymorphisms of the NAD(P)H oxidase and doxorubicin efflux transporters. Chronic ACT was associated with a variant of the NAD(P)H oxidase subunit NCF4 (rs1883112, -212A-->G; symbols with right-pointing arrows, as edited?' odds ratio [OR], 2.5; 95% CI, 1.3 to 5.0). Acute ACT was associated with the His72Tyr polymorphism in the p22phox subunit (rs4673; OR, 2.0; 95% CI, 1.0 to 3.9) and with the variant 7508T-->A (rs13058338; OR, 2.6; 95% CI, 1.3 to 5.1) of the RAC2 subunit of the same enzyme. In agreement with these results, mice deficient in NAD(P)H oxidase activity, unlike wild-type mice, were resistant to chronic doxorubicin treatment. In addition, acute ACT was associated with the Gly671Val variant of the doxorubicin efflux transporter multidrug resistance protein 1 (MRP1) (OR, 3.6; 95% CI, 1.6 to 8.4) and with the Val1188Glu-Cys1515Tyr (rs8187694-rs8187710) haplotype of the functionally similar MRP2 (OR, 2.3; 95% CI, 1.0 to 5.4). Polymorphisms in adrenergic receptors previously demonstrated to be predictive of heart failure were not associated with ACT. CONCLUSIONS: Genetic variants in doxorubicin transport and free radical metabolism may modulate the individual risk to develop ACT.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2005

Phase II trial of carcinoembryonic antigen radioimmunotherapy with 131I-labetuzumab after salvage resection of colorectal metastases in the liver: five-year safety and efficacy results.

PURPOSE: Although complete resection (R0) of liver metastases (LM) remains the treatment of choice for colorectal cancer (CRC) patients amenable to curative therapy, only approximately one third survive for 5 years. The objective of this phase II study was to evaluate the safety and efficacy of radioimmunotherapy (RAIT) after salvage resection of LM. PATIENTS AND METHODS: Twenty-three patients who underwent surgery for LM of CRC received a dose of 40 to 60 mCi/m2 of 131I-labetuzumab, which is a humanized monoclonal antibody against carcinoembryonic antigen. Safety (n = 23), disease-free survival (DFS; n = 19), and overall survival (OS; n = 19) were determined. RESULTS: With a median follow-up of 64 months, the median OS time from the first liver resection for RAIT patients was 68.0 months (95% CI, 46.0 months to infinity), and the median DFS time was 18.0 months (95% CI, 11.0 to 31.0 months). The 5-year survival rate was 51.3%. RAIT benefited patients independently of bilobar involvement, size and number of LM, and resection margins. The major adverse effect was transient myelosuppression, resulting mostly in grade < or = 3 neutropenia and/or thrombocytopenia. CONCLUSION: Because both the median OS and 5-year survival rates seem to be improved with adjuvant RAIT after complete LM resection in CRC, compared with historical and contemporaneous controls not receiving RAIT, these results justify further evaluation of this modality in a multicenter, randomized trial.

Adenocarcinoma↗

PubMed2005

Genome-wide single-nucleotide polymorphism arrays demonstrate high fidelity of multiple displacement-based whole-genome amplification.

Whole-genome DNA amplification by multiple displacement (MD-WGA) is a promising tool to obtain sufficient DNA amounts from samples of limited quantity. Using Affymetrix' GeneChip Human Mapping 10K Arrays, we investigated the accuracy and allele amplification bias in DNA samples subjected to MD-WGA. We observed an excellent concordance (99.95%) between single-nucleotide polymorphisms (SNPs) called both in the nonamplified and the corresponding amplified DNA. This concordance was only 0.01% lower than the intra-assay reproducibility of the genotyping technique used. However, MD-WGA failed to amplify an estimated 7% of polymorphic loci. Due to the algorithm used to call genotypes, this was detected only for heterozygous loci. We achieved a 4.3-fold reduction of noncalled SNPs by combining the results from two independent MD-WGA reactions. This indicated that inter-reaction variations rather than specific chromosomal loci reduced the efficiency of MD-WGA. Consistently, we detected no regions of reduced amplification, with the exception of several SNPs located near chromosomal ends. Altogether, despite a substantial loss of polymorphic sites, MD-WGA appears to be the current method of choice to amplify genomic DNA for array-based SNP analyses. The number of nonamplified loci can be substantially reduced by amplifying each DNA sample in duplicate.

Genome, Human↗

PubMed2005

Application of genomewide SNP arrays for detection of simulated susceptibility loci.

The prospect of SNP-based genomewide association analysis has been extensively discussed, but practical experiences remain limited. We performed an association study using a recently developed array of 11,555 SNPs distributed throughout the human genome. A total of 104 DNA samples were hybridized to these chips with an average call rate of 97% (range 85.3-98.6%). The resulting genomewide scans were applied to distinguish between carriers and noncarriers of 37 test variants, used as surrogates for monogenic disease traits. The test variants were not contained in the chip and had been determined by other methods. Without adjustment for multiple testing, the procedure detected 24% of the test variants, but the positive predictive value was low (2%). Adjustment for multiple testing eliminated most false-positive associations, but the share of true positive associations decreased to 10-12%. We also simulated fine-mapping of susceptibility loci by restricting testing to the immediate neighborhood of test variants (+/-5 Mb). This increased the proportion of correctly identified test variants to 22-27%. Simulation of a bigenic inheritance reduced the sensitivity to 1%. Similarly adverse effect had reduction of allelic penetrance. In summary, we demonstrate the feasibility and considerable specificity of SNP array-based association studies to detect variants underlying monogenic, highly penetrant traits. The outcome is affected by allelic frequencies of chip SNPs, by the ratio between simulated "cases" and "controls," and by the degree of linkage disequilibrium. A major improvement is expected from raising the density of the SNP array.

Alleles↗

PubMed2004

Equivalence test in quantitative reverse transcription polymerase chain reaction: confirmation of reference genes suitable for normalization.

In quantitative reverse transcription-polymerase chain reaction (qRT-PCR), normalization using reference genes is a common useful approach, but the validation of suitable reference genes remains a crucial problem. Use of unconfirmed reference genes may lead to misinterpretation of the expression of target genes. The aim of this study was to adapt an adequate statistical approach to identify and validate reference genes suitable for normalization in qRT-PCR assays. We introduce the equivalence test for the identification of stably expressed reference genes. To evaluate the advantages of this test, the expression of five genes widely used as reference genes (18S, B2M, HPRT1, LMNB1, and SDHA), and of two target genes (TP53 and MMP2), was determined with qRT-PCR in different tissues (clear cell renal cell carcinoma, colon carcinoma, and gastrointestinal stromal tumors). We demonstrate that a stable expression of a reference gene in one tumor type does not predict a stable expression in another tumor type. In addition, we found that even within one tumor type, the expression of a reference gene was not stable for different biological groupwise comparisons. These observations confirm that there is no universal reference gene and underline the importance of specific validation of potential reference genes for any experimental condition.

Adult↗

PubMed2004

High factor VIII levels in venous thromboembolism show linkage to imprinted loci on chromosomes 5 and 11.

High factor VIII (FVIII) levels are known to be a risk factor for deep venous thrombosis, but the mechanisms responsible for high FVIII levels remain unclear. Here, a new phenotype "FVIII level residuum" (FVIII-R) was defined in order to eliminate the impact of common determinants on FVIII levels. We studied 13 families of patients with thrombosis and reproducibly high FVIII levels of unknown origin. Since familial clustering was evident, we looked for a possible genetic basis. A genome scan was performed with 402 evenly spaced microsatellite markers. A quantitative linkage analysis using variance component methods showed suggestive evidence for linkage of FVIII-R with a locus on chromosome 8 (logarithm of odds [LOD] = 2.1). In addition, we performed parametric exploratory linkage analysis of dichotomized FVIII-R, taking a parent-of-origin effect into account. Single-trait-locus MOD-score analysis showed suggestive evidence for linkage under an imprinting model at chromosomes 5 and 11. Furthermore, a 2-trait-locus analysis under a multiplicative model for the loci of chromosomes 5 and 11 yielded a remarkable LOD of 4.44. It confirmed the finding of paternal imprinting, obtained by single-trait-locus analysis, at both loci. Our results suggest that high FVIII levels in venous thromboembolism represent a complex trait caused by several genetic factors.

Chromosomes, Human, Pair 11↗

PubMed2003

Nonparametric longitudinal allele-sharing model.

Basically no methods are available for the analysis of quantitative traits in longitudinal genetic epidemiological studies. We introduce a nonparametric factorial design for longitudinal data on independent sib pairs, modelling the phenotypic quadratic differences as the dependent variable. Factors are the number of alleles shared identically by descent (IBD) and the age categories at which the dependent variable is measured, allowing for dependence due to age. To identify a linked marker a rank statistic tests the influence of IBD group on phenotypic quadratic differences. No assumptions are made on normality or variances of the dependent variable. We apply our method to 71 sib pairs from the Framingham Heart Study data provided at the Genetic Analysis Workshop 13. For all 15 available markers on chromosome 17 we analyzed the influence on systolic blood pressure. In addition, different selection strategies to sample from the whole data are discussed.

Adult↗

PubMedDate not supplied

Diffuse growth pattern affects E-cadherin expression in invasive breast cancer.

We investigated the correlations between growth patterns and E-cadherin expression by immunohistochemistry and the presence of mutations of exons 6-10 of the E-cadherin gene by PCR-SSCP, in 79 cases of invasive lobular and ductal breast cancer. E-cadherin expression showed a tendency to be lower in lobular than in ductal carcinomas (p=0.064). In 60% of lobular carcinomas the diffuse growth pattern and in 72% of ductal carcinomas the compact growth pattern predominated. E-cadherin expression was significantly lower in diffuse than in compact tumor area (p<0.001) and not related to carcinoma type when it was considered in tumor areas with either diffuse (p=0.278) or compact (p=0.128) growth pattern. No mutations were detected. In conclusion, loss of E-cadherin expression is related to an increase of diffuse growth pattern in both lobular and ductal types of breast cancer, and the differential proportions of growth patterns in both tumor types cause the tendency for lower E-cadherin expression in the lobular type.

Adult↗