Biomedical subjects

R Wurm

Publications and source records attributed to R Wurm.

At least 19 recordsLinked to original sources

PubMed2006

123I-IMT SPECT for evaluation of the response to radiation therapy in high grade gliomas: a feasibility study.

Assessing response to radiation therapy in patients with high grade gliomas is needed upon making decisions toward further therapy strategies. Currently used standard imaging tools such as CT and MRI are not sensitive enough to detect early therapy effects. We prospectively investigated if single photon emission computed tomography (SPECT) using radiolabelled amino acid derivate (123)I-methyltyrosine (IMT) would be useful for this aim. 10 patients with histologically proven high grade gliomas, who were candidates for radiation therapy, were enrolled in this investigation. All patients were examined by IMT SPECT before radiation therapy and 4 weeks after the initiation of the hypofractionated application of 40 Gy. Patients were followed up for 39 months; the tumours to background ratios (T/B) for IMT under/before radiation therapy were correlated to survival times. Initially, SPECT depicted an abnormal intratumoural IMT uptake in all patients (mean T/B ratios 1.37-1.87). In four out of 10 patients, the mean T/B ratios decreased by more than 10% under radiation therapy. In six other patients, the BQ decreased by less than 10% or increased. There were no significant correlations between the degree of changes in T/B and survival (r = -0.1, p = 0.973). Serial IMT SPECT measurements allow detection of changes in amino acid accumulation in high-grade gliomas under radiation therapy. However, these changes seem to possess no prognostic value in respect to survival prediction.

Adult↗

PubMed2006

[Brain metastases of lung cancer].

Cerebral metastases are a frequent complication of lung cancer. They often determine patients' prognosis and need urgent therapeutic intervention. Based on histologic type, former therapies, age and performance of the patient, the number of cerebral lesions and the extracerebral tumour activity, individualized treatments are applied. For patients who suffer from non-small cell lung cancer and a single CNS lesion the best results can be achieved if they are surgically resected or receive radiosurgery. Their survival time can be markedly increased in comparison to patients who undergo whole brain irradiation. If multiple metastases are seen in CT or MRI, whole brain irradiation is the therapy to choose. Furthermore it should be initiated if small cell lung cancer metastasizes to the brain. More aggressive local treatment options appear promising, but a clear role for them has not yet been defined. Systemic chemotherapy gains more attention in the treatment of small and non-small cell lung cancer with brain metastases. How to increase the efficacy through simultaneous application of chemo- and radiotherapy is tested in current trials. This article gives an overview on clinical presentation and diagnosis of cerebral metastases in lung cancer and reviews current treatment options.

Anticonvulsants↗

PubMed2006

Glioma assessment using quantitative blood volume maps generated by T1-weighted dynamic contrast-enhanced magnetic resonance imaging: a receiver operating characteristic study.

PURPOSE: To investigate the use of blood volume maps in the non-invasive separation of glioma grades. MATERIAL AND METHODS: T1-weighted quantitative dynamic contrast-enhanced magnetic resonance imaging was used to quantify the fractional intratumoral blood volume of 41 gliomas (World Health Organization (WHO) grades II-IV). Two methods, mean fractional intratumoral blood volume determination and a system based on thresholds for extracting the tumor pixels with the highest vascularization from the blood volume maps, were investigated by means of receiver operating characteristic (ROC) analysis. The thresholds were adjusted using the ROC curve area calculated using the trapezoid method. RESULTS: The ability to separate grade II (WHO) gliomas from grades III-IV was nearly the same for both methods (ROC curve area 0.941 (threshold) versus 0.932 (mean value)) and significantly greater than the ability to separate grade IV (WHO) gliomas from grades II-III (ROC curve area 0.792 (threshold) versus 0.787 (mean value)). The best correspondence with WHO glioma grading was achieved using thresholds corresponding to only the 5.2% of tumor voxels with the largest blood volume for separating grade II gliomas and 4% for separating grade IV gliomas. CONCLUSION: Use of the optimized threshold resulted in matching with the WHO grading system in 74% of cases.

Adolescent↗

PubMed2004

Adaptation of a commercial ELISA for the detection of antibodies against Neospora caninum in bovine milk.

The aim of the present study was to determine whether a commercially available ELISA could be used to examine bovine milk for antibodies against Neospora caninum. In an initial titration experiment, a milk dilution of 1:2 was found optimal to obtain milk results that were linearly correlated to those obtained with corresponding sera. This dilution was then used to examine 791 milk samples from N. caninum infected herds in the commercial ELISA. Milk results of individual animals were compared with those obtained by the same ELISA for the corresponding serum samples. The linear correlation between milk and serum antibody results of individual animals was characterized by R2 = 0.702. Multiple linear regression indicated that the later the stage of lactation at which an animal was sampled, the higher the milk ELISA result was as compared to the serum ELISA result. The examination of the two-graph receiver operating characteristics revealed an optimal cut-off of 0.261 to obtain similar results in the examination of milk and serum. With this cut-off, the test had a sensitivity and specificity relative to the serum results of 90%. The milk-based commercial ELISA classified more aborting dams as positive than the serum-based ELISA with this cut-off. The milk ELISA may be a valuable tool to assess the herd status with regard to abortion caused by N. caninum.

Abortion, Veterinary↗

PubMed2003

Regional distribution of bovine Neospora caninum infection in the German state of Rhineland-Palatinate modelled by Logistic regression.

To obtain a rapid overview over the distribution of bovine Neospora caninum-infections in the German state of Rhineland-Palatinate, an ELISA to determine specific bovine antibodies against a p38 surface antigen of N. caninum tachyzoites was modified to examine bulk milk samples from cattle herds. Experimental bulk milk samples were used to demonstrate that the seroprevalence in a group of animals can be estimated with this ELISA. A cut-off was selected for the specific detection of herds having a seroprevalence > or =10%. About 90% of the dairy herds located in Rhineland-Palatinate were examined. An overall prevalence of bulk milk-positive herds of 7.9% (95% confidence interval 7.0-8.9%), respectively, was determined. Major regional differences in the distribution of bulk milk-positive herds were observed. Prevalences were higher in regions with an increased degree of urbanisation. Logistic regression was applied to model the prevalence of bulk milk-positive herds on a district and city level. Variables describing the dog density, mean temperature in July, mean temperature in January and the total yearly precipitation in districts and cities were able to explain most of the observed variability in the regional prevalences. Our results provide evidence that in addition to risk factors related to individual farms also risk factors related to the farm location such as dog density in the surrounding and climate factors are important in the epidemiology of bovine neosporosis.

Animals↗

PubMed2002

p38-avidity-ELISA: examination of herds experiencing epidemic or endemic Neospora caninum-associated bovine abortion.

An enzyme-linked immunosorbent assay (ELISA) was established to measure the avidity of bovine IgG directed against p38, a surface antigen (NCSRS2) of Neospora caninum tachyzoites. In the sera of dams intravenously infected with N. caninum NC-1, the p38-specific avidity increased from initially below 40% up to avidity indices between 50 and 80% after days 23 and 91 p.i. The p38-avidity-ELISA was used to examine various herds that had experienced endemic and epidemic N. caninum-associated bovine abortions. In herds with endemic abortion, generally high avidity indices of N. caninum-specific IgG were detected. This finding and the observation of an association between the seropositivity of dams and that of their offspring suggested a predominantly vertical transmission of the parasite among the animals of these herds, thus indicating chronic infection of these cattle. In contrast, for herds experiencing epidemic abortion: (i) an association regarding seropositivity of dams and their daughters could not be shown and (ii) a generally low avidity of p38-specific IgG in the sera from aborting dams was determined. This indicates recent postnatal transmission of N. caninum in these herds. A linear regression model explaining the avidity of p38-specific IgG was significantly influenced by the time span between sampling and the occurrence of the first abortion of the epidemic in herds with an N. caninum-associated abortion storm. Another factor significantly contributing to the model was the proportion of dams at risk that had aborted in the herds (i.e. the severity of the abortion epidemic). A possible explanation for this observation is that herds experiencing heavy abortion are sampled earlier after the onset of the epidemic than others that have a less severe abortion storm.

Abortion, Veterinary↗

PubMed2002

Radiation-induced apoptosis in human non-small-cell lung cancer cell lines is secondary to cell-cycle progression beyond the G2-phase checkpoint.

PURPOSE: To characterize the relationship between cell-cycle progression and radiation-induced apoptosis in NSCLC cell lines with different p53 status. MATERIALS AND METHODS: Cell lines with functional (H460, A549) and non-functional p53 (H661 and H520) were irradiated with 20 Gy. Multiparameter flow-cytometry was used to follow the progression of synchronized cells through the cell cycle after irradiation. RESULTS: Delayed apoptosis was observed after cell-cycle progression beyond the G2 block, either in the late G2/M-phase of the same cell cycle being irradiated (H661, H520) or in the G1-phase of the subsequent cell cycle (H460, A549). The apoptotic fraction in H661 and H520 was 60-80% at 144h after irradiation, higher than in A549 and H460 (5 and 35%, respectively). As an alternative to apoptosis in cells cycling beyond the G2 restriction point, hyperploid cells were generated by all cell lines. Inhibition of cell-cycle progression through the G2/M-phase efficiently reduced the induction of late apoptosis. After irradiation in S-phase, 50-60% of cells with functional p53 remained arrested at the G2 restriction point until 144 h post-irradiation, while only 20% of the H661 or H520 did so. CONCLUSIONS: These data characterize radiation-induced apoptosis in NSCLC cell lines as a removal pathway of clonogenically inactivated cells secondary to cell-cycle progression beyond G2/M, and is unlikely to be a critical factor for cellular radiation sensitivity.

Apoptosis↗

PubMed2001

Bovine neosporosis: immunoblot improves foetal serology.

The purpose of the study is the comparative evaluation of the immunofluorescent antibody test (IFAT) and an immunoblot (IB) test for the examination of foetal fluids for specific antibodies against Neospora caninum. Peritoneal and pleural fluids as well as abomasal contents were analysed. The results of the serological examinations were compared to those obtained by histological, immunohistochemical, and PCR analysis of foetal tissues as well as to the results of maternal serological examinations. Fluids were used undiluted in the IB and reactions against six immunodominant antigens were recorded. When the recognition of at least two immunodominant antigens was regarded as positive, the agreement of the IB with other diagnostic methods was good to moderate as characterised by kappa-values of 0.76 (histology/immunohistochemistry), 0.69 (maternal serology) and 0.54 (PCR on foetal tissues). The IB results agreed better with the results of the other diagnostic methods than those of the IFAT. The higher relative sensitivity of the IB was regarded as the main reason for the better agreement. However, also the specificity of the IB was superior to that of the IFAT in relation to histology/immunohistochemistry, maternal serology and PCR.

Abomasum↗

PubMed2001

[Current and future strategies in interdisciplinary treatment of medulloblastomas, supratentorial PNET (primitive neuroectodermal tumors) and intracranial germ cell tumors in childhood].

BACKGROUND: The chances for cure in medulloblastoma, supratentorial primitive neuroectodermal tumors (stPNET) and intracranial germ cell tumors have decisively improved within the last decades. Today long-term survival in the range between 60% and 80% and more than 90%, respectively, can be achieved. The low incidence of brain tumors in childhood and the necessity for optimal patient care has led to the fact that more than 90% of children are treated within national and international controlled studies today in order to assure a constant improvement of therapeutic outcome. Recent developments in neurosurgery achieved complete tumor resections in the majority of children at a low risk for morbidity and mortality. METHODS: Systemic irradiation of neuroaxis is an essential part in the management of medulloblastoma, stPNET and intracranial germ cell tumors. The introduction of quality assurance programs in radiooncology assures a precise radiotherapy of target volumes and is a prerequisite to improve survival. RESULTS: Hyperfractionated radiotherapy has the potential of increasing dose to tumor more safely without increasing the risk for late adverse effects. Pilot studies revealed excellent tumor control in medulloblastoma with acceptable acute toxicity and a long-term survival of up to 96%. In medulloblastoma stereotactic radiation techniques reveal an acceptable toxicity and promising results in tumor control in recurrent disease or as primary treatment. They are now part of future treatment protocols in case of persisting residual tumor. Radiotherapy alone in pure germinoma is continuously yielding high cure rates. In secreting germ cell tumors cisplatin containing chemotherapies in conjunction with radiotherapy achieve a long-term survival rate of 80% today. Especially in high risk medulloblastoma and secreting germ cell tumors chemotherapies are playing an increasingly important role in the interdisciplinary management. It can be expected that future developments of chemotherapeutic protocols and the introduction of new cytostatic substances will further improve the therapeutic outcome. CONCLUSIONS: The therapeutic endeavors of all those caring for children are aiming to study modifications of the therapeutic components in the interdisciplinary approach in order to optimize the therapeutic strategies. In future the affected children and young adolescents should be accrued for the forthcoming cooperative, prospective trial HIT 2000 and ongoing trial SIOP CNS GCT 96, respectively, in order to provide the body of data supporting the selection of novel and optimized approaches for future treatment strategies.

Adolescent↗

PubMed2001

Comparison of dynamic contrast-enhanced MRI with WHO tumor grading for gliomas.

Assessment of vascular proliferation as an important grading criterion has been employed in both the histologic and the radiologic characterization of gliomas with encouraging results. Perfusion in gliomas can be measured by dynamic contrast-enhanced magnetic resonance imaging (dMRI). The goal of this study was to develop a model for simultaneously quantifying the fractional volumes of different tissue compartments of gliomas by dMRI. A modified method for evaluating dynamic contrast-enhanced MR images is presented which simultaneously determines the fractional vascular, interstitial, and cellular volumes of gliomas. This method differs from techniques used in other studies in that it is based on a three-compartment model: a single blood compartment and two interstitial ones. The fractional volume maps are compared with the WHO glioma grading. The results show the method to be feasible. Using cerebral blood volume (CBV), dMRI grading showed a correspondence with WHO grading in 83% of the cases (20/24 gliomas WHO grades II-IV). The use of interstitial volume maps can also be helpful, for instance, in differentiating gliomas from other brain tumors. As a supplement to conventional MRI, dynamic MR techniques thus provide a useful tool for improving in vivo glioma characterization.

Adolescent↗

PubMed2001

Porcine teschoviruses comprise at least eleven distinct serotypes: molecular and evolutionary aspects.

Nucleotide sequencing and phylogenetic analysis of 10 recognized prototype strains of the porcine enterovirus (PEV) cytopathic effect (CPE) group I reveals a close relationship of the viral genomes to the previously sequenced strain F65, supporting the concept of a reclassification of this virus group into a new picornavirus genus. Also, nucleotide sequences of the polyprotein-encoding genome region or the P1 region of 28 historic strains and recent field isolates were determined. The data suggest that several closely related but antigenically and molecular distinct serotypes constitute one species within the proposed genus Teschovirus. Based on sequence data and serological data, we propose a new serotype with strain Dresden as prototype. This hitherto unrecognized serotype is closely related to porcine teschovirus 1 (PTV-1, former PEV-1), but induces type-specific neutralizing antibodies. Sequencing of field isolates collected from animals presenting with neurological disorders prove that other serotypes than PTV-1 may also cause polioencephalomyelitis of swine.

3' Untranslated Regions↗

PubMed2000

[For which tumor entities are effects of overall treatment time on the results of radiotherapy evident?].

BACKGROUND AND METHOD: The effect of overall treatment time on therapeutic outcome was analyzed comparing the randomized trials on accelerated fractionation for the different tumor entities. Only studies using radiotherapy as the definitive locoregional treatment modality were included. RESULTS AND CONCLUSION: Randomized studies were performed for squamous cell carcinomas of the head and neck region as well as for small-cell and non-small-cell carcinomas of the lung. These studies showed, that locoregional control can be improved by accelerated fractionation in comparison to conventional fractionation with the same total dose. With the same antitumor effectiveness of both fractionation schedules, total dose can be reduced using accelerated fractionation.

Carcinoma, Non-Small-Cell Lung↗

PubMed2000

Detection of porcine enteroviruses by nRT-PCR: differentiation of CPE groups I-III with specific primer sets.

Porcine enteroviruses (PEV) comprising at least 13 serotypes grouped into three species are described as causative agents of neurological disorders, fertility disorders, and dermal lesions of swine. Despite their well-documented acid stability, enteric infection route, and similarity of clinical symptoms, most of the porcine enterovirus (PEV) serotypes are set apart from the genus Enterovirus of the Picornaviridae. Hence, PCR procedures used commonly to detect enteroviruses are not applicable to epizootic relevant PEV serotypes. A nested RT-PCR protocol is described now suited to detect all known porcine enterovirus serotypes using three sets of primer pairs. These primer pairs were designed to amplify either highly conserved sequences of the 5'-nontranslated region (5'-NTR) or the polymerase gene region of the relevant virus species. All 13 acknowledged serotypes of three PEV species and several field isolates of clinical specimens were detectable. The specificity of the PCR procedure is supported by the observation that RT-PCR-positive field isolates coincide with serological PEV classification. PEV PCR is more rapid and less laborious than the time-consuming virus isolation by tissue culture techniques over several passages and serotyping. Because other viruses such as classical swine fever virus, pseudorabies virus, porcine parvovirus, swine vesicular disease virus, and foot-and-mouth disease virus may cause diseases with similar clinical symptoms, PCR detection of all PEVs closes a diagnostic gap and offers the opportunity to use comprehensive PCR procedures for the diagnosis of all relevant viruses causing such symptoms.

5' Untranslated Regions↗

PubMed2000

Serological investigations of red foxes (Vulpes vulpes L.) for determination of the spread of tick-borne encephalitis in Northrhine-Westphalia.

Serum samples from 786 red foxes shot between January 1995 and August 1996 in the southern half of Northrhine-Westphalia, located in western Germany, were tested for the presence of antibodies against tick-borne encephalitis (TBE) virus using the Immunozym FSME IgG All Species-ELISA (Immuno, Heidelberg, Germany) as a screening test: 759 sera were negative, 23 (2.9%) were borderline, and four (0.5%) were positive. Nine of the 27 ELISA reactive sera were confirmed by the TBE Western-Blot (Immuno, Heidelberg, Germany). Furthermore these 27 sera were tested for neutralizing antibodies by means of a plaque reduction neutralization test (PRNT) against TBE and West Nile viruses. Only one single serum was found to have a neutralization titre (+1:800 PRNT80) against TBE virus. All other 26 sera were negative for neutralizing antibodies against TBE or West Nile virus. Since the titre of the single serum is low, it can be interpreted that if TBE virus is present, its prevalence is extremely low. Northrhine-Westphalia is not classified as a TBE-endemic area. Further calculated serological testing of game and virological investigation of collected ticks in the affected area seem to be meaningful and necessary.

Animals↗

PubMed2000

Protection of DNA from radiation-induced double-strand breaks: influence of replication and nuclear proteins.

PURPOSE: To study the protective effect of histone and non-histone proteins on double-strand break (dsb) induction in replicating S-phase DNA as well as bulk DNA of plateau phase human tumour cells. MATERIALS AND METHODS: Induction of dsb was studied in two human adenocarcinoma cell lines: Colo320HSR and MCF-7. To assess the influence of chromatin structure on radiation-induced DNA dsb, different nuclear preparations of cells, either continuously labelled with 14C or pulse labelled with 3H, were assessed by pulsed-field gel electrophoresis (PFGE). RESULTS AND CONCLUSIONS: Stepwise removal of DNA-bound proteins from the chromatin increased the amount of radiation-induced dsb in both cell lines. However, the protective effect of DNA-associated proteins on dsb induction was significantly reduced in DNA of replicating S-phase cells compared with bulk DNA of plateau phase cells. These data show that proteins associated with the DNA have a different protective effect on radiation-induced dsb, rendering replicating DNA with open chromatin structure more sensitive to dsb induction by ionizing radiation.

Chromatin↗

PubMed1999

Serological differences in Neospora caninum-associated epidemic and endemic abortions.

A sandwich enzyme-linked immunosorbent assay (ELISA) for the sensitive and specific detection of bovine antibodies to Neospora caninum was developed and evaluated using sera from cattle experimentally infected with N. caninum, Toxoplasma gondii, Sarcocystis cruzi, Sarcocystis hominis, Sarcocystis hirsuta, Eimeria bovis, Cryptosporidium parvum, Babesia divergens, and field sera from naturally exposed animals. Field sera were classified using a gold standard that included the results from an indirect fluorescent antibody test (IFAT) and an immunoblot (IB). Based on these gold standard results, i.e., IFAT-IB results, an equal relative sensitivity and specificity of 94.2%(theta0) was reached when a cutoff of 0.034 (d0) was employed. The analysis of IFAT-IB-positive field sera showed that within groups of aborting and nonaborting dams, the animals from herds with endemic N. caninum-associated abortions had significantly higher ELISA indices than animals from herds with N. caninum-associated epidemic abortions. By contrast, IFAT-IB-positive aborting dams from herds with endemic N. caninum-associated abortions had significantly lower IFAT titers than IFAT-IB-positive aborting dams from herds with epidemic N. caninum-associated abortions. This is the first time that statistically significant serological differences between herds exhibiting epidemic and endemic N. caninum-associated abortions are described.

Abortion, Veterinary↗

PubMed1998

The efficiency of vertical transmission of Neospora caninum in dairy cattle analysed by serological techniques.

The association of Neospora caninum infections with cattle families was examined in a dairy cattle herd with sporadic abortions using three different serological tests. Cattle seropositive for N. caninum clustered in six families, three of which encountered abortions. In absence of age-related differences in the N. caninum seroprevalence, the family association of N. caninum infection indicated that congenital infection represented the predominant route of transmission in this herd. Fourteen (93%) out of 15 descendants of 10 seropositive cows were seropositive themselves. Only one female calf of a seropositive cow remained seronegative and gave birth to a calf which was tested seronegative again. Only one seronegative cow that had two seronegative descendants also gave birth to one seropositive calf. This was the only indication for potential postnatal transmission that occurred in the herd. The results of this study suggest that the N. caninum-infection can be maintained over several generations at a nearly constant prevalence level, apparently without a need for dispersion by an definitive host.

Abortion, Veterinary↗

PubMed1998

Thymoma: prognostic factors and treatment outcomes.

BACKGROUND: The objective of this study was to establish prognostic factors for thymoma and determine the impact of surgery with or without postoperative radiotherapy. METHODS: Seventy patients treated at the University Hospital Düsseldorf during the period 1954-1991 were retrospectively studied. All thymoma patients underwent surgery, 22 received postoperative radiotherapy, and 3 also received chemotherapy. According to thymoma staging as described previously by Masaoka et al., 21% were Stage I, 26% Stage II, 43% Stage III, 7% Stage IVA, and 3% Stage IVB. Lymphocytic type disease was found in 36% of patients, lymphoepithelial type in 33%, epithelial type in 23%, and spindle cell type in 9%. The relevance of Karnofsky performance status (KPS), gender, age, myasthenia gravis, histology, tumor size, and stage to survival was determined by univariate analysis, and their independent significance was tested by multivariate analysis. Survival rates were calculated using the Kaplan-Meier method and the log rank test. RESULTS: In univariate analysis, KPS (P < 0.001), histologic type (P=0.0093), and stage (P=0.0001) proved to be significant predictors of overall survival. Spindle cell type was associated with the best and epithelial type the worst prognosis; patients with the latter type had a 5-year survival rate of 30%. Multivariate analysis revealed that stage, histology, and KPS were predictive of overall survival. In Stages III and IV, relapses were reduced by postoperative radiotherapy from 50% to 20%. The site of relapse was outside the irradiated area in 80% of patients. Disease free survival (P=0.36) and median survival (P=0.72) of patients with completely resected advanced thymomas did not differ from that for patients with incompletely resected tumors who received radiotherapy. CONCLUSIONS: Postoperative radiotherapy can improve local control in patients with advanced thymoma. Survival after incomplete resection is not compromised when postoperative radiotherapy is employed. KPS should be considered an important prognostic factor in future studies.

Adolescent↗