PubMed Health⌕ Search

Biomedical subjects

Florian Otto

Publications and source records attributed to Florian Otto.

17 recordsLinked to original sources
PubMed2006

The epitope recognized by rituximab.

Rituximab is a monoclonal antibody widely used in the treatment of malignant lymphoma and autoimmunity. Its epitope within the B-cell antigen CD20 is largely unknown. We used phage display libraries to select peptides binding to rituximab. Enriched peptides showed 2 sequence patterns: one motif (CALMIANSC) is related to (170)ANPS(173) within CD20, while another motif (WEWTI) may mimic the CD20 segment (182)YCYSI(185). Phages displaying either motif specifically bound rituximab. Binding to rituximab by the CD20 peptides ANPS and YCYSI was weak when used separately and enhanced when both peptides were linked. Recombinant CD20 extracellular loop proteins blocked binding of the selected CWWEWTIGC phage to rituximab, suggesting that CWWEWTIGC mimics the epitope. Blocking capacity was strongly reduced upon mutation of the CD20 strings ANPS or YCYSI. We conclude that rituximab binds a discontinuous epitope in CD20, comprised of (170)ANPS(173) and (182)YCYSI(185), with both strings brought in steric proximity by a disulfide bridge between C(167) and C(183).

Amino Acid Sequence↗
PubMed2006

Anemia and long-term outcome in adjuvant and neoadjuvant radiochemotherapy of stage II and III rectal adenocarcinoma: the Freiburg experience (1989-2002).

AIM: To evaluate the long-term outcome of standard 5-FU based adjuvant or neoadjuvant radiochemotherapy and to identify the predictive factors, especially anemia before and after radiotherapy as well as hemoglobin increase or decrease during radiotherapy. METHODS: Two hundred and eighty-six patients with Union International Contre Cancer (UICC) stage II and III rectal adenocarcinomas, who underwent resection by conventional surgical techniques (low anterior or abdominoperineal resection), received either postoperative (n=233) or preoperative (n=53) radiochemotherapy from January 1989 until July 2002. Overall survival (OAS), cancer-specific survival (CSS), disease-free survival (DFS), local-relapse-free (LRS) and distant-relapse-free survival (DRS) were evaluated using Kaplan-Meier, Log-rank test and Cox's proportional hazards as statistical methods. Multivariate analysis was used to identify prognostic factors. Median follow-up time was 8 years. RESULTS: Anemia before radiochemotherapy was an independent prognostic factor for improved DFS (risk ratio 0.76, P=0.04) as well as stage, grading, R status (free radial margins), type of surgery, carcinoembryonic antigen (CEA) levels, and gender. The univariate analysis revealed that anemia was associated with impaired LRS (better local control) but with improved DFS. In contrast, hemoglobin decrease during radiotherapy was an independent risk factor for DFS (risk ratio 1.97, P=0.04). During radiotherapy, only 30.8% of R0-resected patients suffered from hemoglobin decrease compared to 55.6% if R1/2 resection was performed (P=0.04). The 5-year OAS, CSS, DFS, LRS and DRS were 47.0%, 60.0%, 41.4%, 67.2%, and 84.3%, respectively. Significant differences between preoperative and postoperative radiochemotherapy were not found. CONCLUSION: Anemia before radiochemotherapy and hemoglobin decrease during radiotherapy have no predictive value for the outcome of rectal cancer. Stage, grading, R status (free radial margins), type of surgery, CEA levels, and gender have predictive value for the outcome of rectal cancer.

Adenocarcinoma↗
PubMed2006

Influence of groin incision, duration of ischemia, and prostaglandin E1 on ischemia-reperfusion injury of the lower limb.

OBJECTIVE: The influences of groin incision, duration of ischemia, and the effects of prostaglandin E1 (PGE1) on ischemia-reperfusion (I/R) injury of the hind limb in rabbits were evaluated. DESIGN: A prospective study. SETTING: Laboratory. PARTICIPANTS: In 64 rabbits, bilateral hind limb ischemia was induced by occlusion of the abdominal aorta. Volume changes, neuromuscular function of the hind limb, and creatine kinase (CK) release were measured as variables of tissue injury. INTERVENTIONS: Eight rabbits served as untreated controls (CON). In 2 groups (each n = 14), 3 hours of ischemia were followed by 3 hours of reperfusion (I/R). In 2 different groups (each n = 14), 45 minutes of ischemia were followed by 2 hours of reperfusion. To determine effects of PGE1, 1 I/R group of each ischemia duration was treated intravenously with 80 ng/kg/min of PGE1 starting 30 minutes after the onset of ischemia (I/R-PGE1). To determine effects of groin incision on edema formation, volume changes were determined in the "operated" right (CON-R, 3h-R, 3h-PGE1-R and 45 min-R, 45 min-PGE1-R) or in the "nonoperated" left hind limb (CON-L, 3h-L, 3h-PGE1-L and 45 min-L, 45 min-PGE1-L), representing a subgroup analysis. MEASUREMENTS AND MAIN RESULTS: Volume changes after I/R occurred only in operated legs after ischemia (3h-R: 2.3 +/- 0.3 mL, p < 0.0001 v CON-R and 3h-L; 45 min-R: 0.8 +/- 0.2 mL, p < 0.01 v 45 min-L). PGE1 reduced edema formation in the operated legs (3h-PGE1-R: 1.0 +/- 0.4 mL, p < 0.0001 v 3h-R; 45 min-PGE1-R: 0.5 +/- 0.3 mL, p = 1.0 v 45 min-R). Groin incision without I/R had no effect on edema formation (CON-R: -0.13 +/- 0.17 mL of baseline). The increase of CK release from 616 +/- 584 U/L in controls to 5,921 +/- 2,156 U/L after 3 hours of ischemia (p < 0.001) was attenuated by treatment with PGE1 (3,732 +/- 2,653, p < 0.05 v I/R). Forty-five minutes of ischemia did not lead to cellular damage as measured by CK release (I/R: 606 +/- 364 U/L). Recovery of neuromuscular function was not affected by PGE1. CONCLUSION: Development of edema during I/R depends on groin incision of the hind limb and on the duration of ischemia. The I/R injury is attenuated by PGE1 treatment, in terms of reduced edema formation and CK release, but not in terms of neuromuscular function.

Alprostadil↗
PubMed2005

Gene deregulation in gastric cancer.

Despite its decreasing frequency in the Western world during recent decades, gastric cancer is still one of the leading causes of cancer-related deaths worldwide. Due to the oligosymptomatic course of early gastric cancer, most cases are diagnosed in the advanced stages of the disease. The curative potential of current standard treatment continues to be unsatisfactory, despite multimodal approaches involving surgery, chemotherapy and radiotherapy. Novel therapeutics including small molecules and monoclonal antibodies are being developed and have been partially introduced into clinical use in connection with neoplastic diseases such as chronic myeloid leukemia, non-Hodgkin's lymphoma and colorectal cancer. Thorough understanding of the changes in gene expression occurring during gastric carcinogenesis may help to develop targeted therapies and improve the treatment of this disease. Novel molecular biology techniques have generated a wealth of data on up- and down-regulation, activation and inhibition of specific pathways in gastric cancer. Here, we provide an overview of the different aspects of aberrant gene expression patterns in gastric cancer.

Animals↗
PubMed2005

Mammalian Groucho homologs: redundancy or specificity?

The proteins termed TLE in humans, Grg in mice and Groucho in Drosophila constitute a family of transcriptional corepressors. In mammalians there are five different genes encoding an even larger number of proteins. Interactions between these TLE/Grg proteins and an array of transcription factors has been described. But is there any specificity? This review tries to make a case for a non-redundant function of individual TLE/Grg proteins. The specificity may be brought about by a tightly controlled temporo-spatial expression pattern, post-translational modifications, and subtle structural differences leading to distinct preferences for interacting transcription factors. A confirmation of this concept will ultimately need to come from genetic experiments.

Animals↗
PubMed2005

Control of RUNX2 isoform expression: the role of promoters and enhancers.

The three mammalian RUNX genes constitute the family of runt domain transcription factors that are involved in the regulation of a number of developmental processes such as haematopoiesis, osteogenesis and neuronal differentiation. All three genes show a complex temporo-spatial pattern of expression. Since the three proteins are probably mutually interchangeable with regard to function, most of the specificity of each family member seems to be based on a tightly controlled regulation of expression. While RUNX gene expression is driven by two promoters for each gene, the promoter sequence alone does not seem to suffice for a proper expressional control. This review focuses on the available evidence for the existence of such control mechanisms and studies aiming at discovering cis-acting regulatory sequences of the RUNX2 gene.

Animals↗
PubMed2004

Identification of novel genes of the bone-specific transcription factor Runx2.

INTRODUCTION: The transcription factor Runx2 is a key regulator of osteoblast development and plays a role in chondrocyte maturation. The identification of transcriptional target genes of Runx2 may yield insight into how osteoblastic differentiation is achieved on a molecular level. MATERIALS AND METHODS: Using a differential hybridization technique (selective amplification through biotin and restriction-mediated enrichment [SABRE]) and cDNA microarray analysis, 15 differentially expressed genes were identified using mRNA from C3H 10Tl/2 cells with constitutive and inducible overexpression of Runx2. RESULTS AND CONCLUSIONS: Among the 15 genes identified, 4 encode the extracellular matrix proteins Ecml, Mgp, Fbn5, and Osf-2, three represent the transcription factors Esxl, Osrl, and Sox9, whereas others were Ptn, Npdc-1, Higl, and Tem l. The gene for Pttg1ip was upregulated in Runx2-expressing cells. Pttg1ip is widely expressed during development, but at highest levels in limbs and gonads. The Pttg1ip promoter binds Runx2 in a sequence specific manner, and Runx2 is able to transactivate the Pttg lip promoter in MC3T3-El cells. Therefore, Pttg1ip is likely tobe a novel direct transcriptional target gene of Runx2. In conclusion, the genes identified in this study are important candidates for mediating Runx2 induced cellular differentiation.

Animals↗
PubMed2003

Upstream and downstream targets of RUNX proteins.

In recent years, the in vivo role of the three members of the RUNX family of transcription factors has in part been elucidated. While Runx1 is essential for mature haematopoiesis and Runx2 for osteochondrogenesis, Runx3 has a function in the nervous system. Translocations and mutations affecting the RUNX1 gene are clearly implicated in leukemogenesis whereas recent data suggest that changed expression levels of RUNX3 may be involved in gastric carcinogenesis. Germ line mutations in RUNX2 have been identified in patients with an autosomal dominant skeletal disorder, cleidocranial dysplasia. While a number of pathways have been delineated that regulate RUNX activity, transcription factors binding to RUNX promoters are only beginning to be identified. A growing number of genes have been characterised that are being regulated in their transcriptional activity by different RUNX proteins. Whether a particular RUNX protein specifically targets a defined subset of downstream genes or whether there is some redundancy as to which RUNX protein activates which target promoter remains to be elucidated.

Animals↗
PubMed2003

Expression of galectin-3 in skeletal tissues is controlled by Runx2.

The beta-galatoside-specific lectin galectin-3 is expressed in vivo in osteoblasts as well as in epiphyseal cartilage. Here we show that in vitro, galectin-3 expression is up-regulated in the preosteoblastic cell line MC3T3-E1 during the matrix maturation stage of the osteoblast developmental sequence. Expression persists into late differentiation stages when the mature osteoblastic phenotype is established. The skeletal expression pattern of galectin-3 overlaps at many sites with that of the transcription factor Runx2. Runx2 is a key regulator of osteoblast development and necessary for chondrocyte differentiation in the growth plate. Both human and mouse galectin-3 promoters contain putative Runx-binding sites. The constitutive or inducible forced expression of Runx2 is sufficient for the onset of galectin-3 transcription in the mesenchymal precursor cell line C3H10T1/2. Moreover, Runx2 is able to bind to at least two sites in the galectin-3 promoter region. The crucial role of Runx2 was confirmed in Runx2-deficient mice, which are devoid of galectin-3 expression in skeletal cells. The overlapping expression pattern of galectin-3 with the other two members of the Runt family of transcription factors (Runx1 and Runx3) points to a potential regulation of the galectin-3 gene (LGALS3) by these factors in hematopoietic, skin, and dorsal root ganglial cells.

Animals↗
PubMed2003

Runx3 knockouts and stomach cancer.

Gene targeting often results in knockout mice that show several phenotypes, some of which may not directly relate to the intrinsic function of the disrupted gene. Hence, to study the biological function of genes using knockout mice, one must identify the defects that are directly due to the loss of the targeted gene. Runx3 is a transcription factor that regulates lineage-specific gene expression in developmental processes. Recently, two groups produced Runx3 knockout mice. Two comparable defects were identified in both knockout strains, one involved neurogenesis and the other thymopoiesis. In addition, a stomach defect pertaining to gastric cancer was observed in one of the mutant strains, but not in the other. Here, we assess the differences between the two Runx3 mutant strains and discuss further studies that could reconcile these discrepancies. This article highlights the difficulties of inferring gene function through the interpretation of knockout phenotypes.

Animals↗
PubMed2003

Sevoflurane confers additional cardioprotection after ischemic late preconditioning in rabbits.

BACKGROUND: Sevoflurane exerts cardioprotective effects that mimic the early ischemic preconditioning phenomenon (EPC) by activating adenosine triphosphate-sensitive potassium (KATP) channels. Ischemic late preconditioning (LPC) is an important cardioprotective mechanism in patients with coronary artery disease. The authors investigated whether the combination of LPC and sevoflurane-induced preconditioning results in enhanced cardioprotection and whether opening of KATP channels plays a role in this new setting. METHODS: Seventy-three rabbits were instrumented with a coronary artery occluder. After recovery for 10 days, they were subjected to 30 min of coronary artery occlusion and 120 min of reperfusion (I/R). Controls (n = 14) were not preconditioned. LPC was induced in conscious animals by a 5-min period of coronary artery occlusion 24 h before I/R (LPC, n = 15). Additional EPC was induced by a 5-min period of myocardial ischemia 10 min before I/R (LPC+EPC, n = 9). Animals of the sevoflurane (SEVO) groups inhaled 1 minimum alveolar concentration of sevoflurane for 5 min at 10 min before I/R with (LPC+SEVO, n = 10) or without (SEVO, n = 15) additional LPC. The KATP channel blocker 5-hydroxydecanoate (5-HD, 5 mg/kg) was given intravenously 10 min before sevoflurane administration (LPC+SEVO+5-HD, n = 10). RESULTS: Infarct size of the area at risk (triphenyltetrazolium staining) was reduced from 45 +/- 16% (mean+/-SD, control) to 27 +/- 11% by LPC (P < 0.001) and to 27 +/- 17% by sevoflurane (P = 0.001). Additional sevoflurane administration after LPC led to a further infarct size reduction to 14 +/- 8% (LPC+SEVO, P = 0.003 vs. LPC; P = 0.032 vs. SEVO), similar to the combination of LPC and EPC (12 +/- 8%; P = 0.55 vs. LPC+SEVO). Cardioprotection induced by LPC+SEVO was abolished by 5-HD (LPC+SEVO+5-HD, 41 +/- 19%, P = 0.001 vs. LPC+SEVO). CONCLUSIONS: Sevoflurane administration confers additional cardioprotection after LPC by opening of KATP channels.

ATP-Binding Cassette Transporters↗
PubMed2002

The Runx3 transcription factor regulates development and survival of TrkC dorsal root ganglia neurons.

The RUNX transcription factors are important regulators of linage-specific gene expression in major developmental pathways. Recently, we demonstrated that Runx3 is highly expressed in developing cranial and dorsal root ganglia (DRGs). Here we report that within the DRGs, Runx3 is specifically expressed in a subset of neurons, the tyrosine kinase receptor C (TrkC) proprioceptive neurons. We show that Runx3-deficient mice develop severe limb ataxia due to disruption of monosynaptic connectivity between intra spinal afferents and motoneurons. We demonstrate that the underlying cause of the defect is a loss of DRG proprioceptive neurons, reflected by a decreased number of TrkC-, parvalbumin- and beta-galactosidase-positive cells. Thus, Runx3 is a neurogenic TrkC neuron-specific transcription factor. In its absence, TrkC neurons in the DRG do not survive long enough to extend their axons toward target cells, resulting in lack of connectivity and ataxia. The data provide new genetic insights into the neurogenesis of DRGs and may help elucidate the molecular mechanisms underlying somatosensory-related ataxia in humans.

Afferent Pathways↗
PubMed2002

Genomic characterization of the RUNX2 gene of Fugu rubripes.

A 105 kb Fugu rubripes genomic region containing the RUNX2 ortholog (frunx2) was sequenced and analysed. Spanning 32 kb, frunx2 is seven times smaller than its human orthologue (223 kb). By comparison of Fugu and human genomic environment a stretch of conserved synteny, comprising the neighbouring genes on both sides, was identified. Except one exon that is alternatively spliced in human RUNX2, all other seven exons could be identified in frunx2. The predicted protein sequence of frunx2 shows a high degree of sequence conservation compared with RUNX2 (83% identity). Like all human paralogues, frunx2 possesses two promoter regions separated by a large intron. Both promoter regions are conserved between the two species and contain several RUNX binding sites pointing to a self-regulatory function. Three further conserved non-coding regions were identified possibly functioning as enhancer elements for tissue-specific expression of RUNX2.

Amino Acid Sequence↗
PubMed2002

Mutations in the RUNX2 gene in patients with cleidocranial dysplasia.

Cleidocranial dysplasia (CCD) is a autosomal dominant disorder characterized by skeletal anomalies such as patent fontanels, late closure of cranial sutures with Wormian bones, late erupting secondary dentition, rudimentary clavicles, and short stature. The locus for this disease was mapped to chromosome 6p21. RUNX2 is a member of the runt family of transcription factors and its expression is restricted to developing osteoblasts and a subset of chondrocytes. Mutations in the RUNX2 gene have been shown to cause CCD. Chromosomal translocations, deletions, insertions, nonsense and splice-site mutations, as well as missense mutations of the RUNX2 gene have been described in CCD patients. Although there is a wide spectrum in phenotypic variability ranging from primary dental anomalies to all CCD features plus osteoporosis, no clear phenotype-genotype correlation has been established. However analysis of the three-dimensional structure of the DNA binding runt domain of the RUNX proteins and its interaction with DNA, as well as the cofactor CBFB, start to provide an insight into how missense mutations affect RUNX2 function.

Amino Acid Sequence↗
PubMedDate not supplied

Adjuvant radiochemotherapy of stage II and III rectal adenocarcinoma: role of CEA and CA 19-9.

BACKGROUND: This analysis was undertaken to evaluate the impact of pre-radiotherapy CEA and CA 19-9 values on clinical outcome of locally advanced rectal cancer. PATIENTS AND METHODS: Retrospective data were collected from patients (n=203) with UICC stage II and III rectal adenocarcinomas, who underwent low anterior or abdominoperineal resection and received post-operative or pre-operative radiochemotherapy from January 1989 until July 2002. The rates of survival and distant and local recurrences were evaluated using Kaplan-Meier survival analysis, Log-rank test and Cox's proportional hazards (median follow-up 8 years). Multivariate analysis was used to assess the prognostic value of CEA and CA 19-9. RESULTS: The 5-year actuarial rates for patients with normal (n =118) and elevated (n=88) CEA values were as follows: overall survival 62.4% and 32.0% (p<0.001), local control 73.5% and 55.0% (p=0.007), and absence of distant metastasis 83.3% and 88.0% (n.s.), respectively. Similar results were obtained for patients with normal (n=82) and elevated (n = 10) CA 19-9 values: overall survival 60.7% and 14.0% (p=0.007), local control 83.7% and 80.0% (n.s.), and absence of distant metastasis 64.9% and 75.0% (n.s.), respectively. After adjustment for TNM stage, sex, age, LDH, tumor site and grading, the elevation of CEA proved to be an independent prognostic factor for overall survival (relative risk of 1.01 per ng/ml, CI 1.002 - 1.01; p=0.005). CONCLUSION: This study confirmed the prognostic value of pre-radiotherapy CEA and CA 19-9 in patients with stage II or III rectal carcinoma.

Adenocarcinoma↗