Biomedical subjects

M Wirth

Publications and source records attributed to M Wirth.

At least 19 recordsLinked to original sources

PubMed2006

Sex differences in semantic processing: event-related brain potentials distinguish between lower and higher order semantic analysis during word reading.

Behavioral studies suggest that women and men differ in the strategic elaboration of verbally encoded information especially in the absence of external task demand. However, measuring such covert processing requires other than behavioral data. The present study used event-related potentials to compare sexes in lower and higher order semantic processing during the passive reading of semantically related and unrelated word pairs. Women and men showed the same early context effect in the P1-N1 transition period. This finding indicates that the initial lexical-semantic access is similar in men and women. In contrast, sexes differed in higher order semantic processing. Women showed an earlier and longer lasting context effect in the N400 accompanied by larger signal strength in temporal networks similarly recruited by men and women. The results suggest that women spontaneously conduct a deeper semantic analysis. This leads to faster processing of related words in the active neural networks as reflected in a shorter stability of the N400 map in women. Taken together, the findings demonstrate that there is a selective sex difference in the controlled semantic analysis during passive word reading that is not reflected in different functional organization but in the depth of processing.

Adult↗

PubMed2006

Bicalutamide (Casodex) 150 mg plus standard care in early non-metastatic prostate cancer: results from Early Prostate Cancer Trial 24 at a median 7 years' follow-up.

Trial 24, one of three ongoing trials in the Early Prostate Cancer programme, is evaluating the efficacy and tolerability of bicalutamide (Casodex) 150 mg following standard care (radiotherapy, radical prostatectomy or watchful waiting) in patients with early, non-metastatic prostate cancer. At 7 years' median follow-up, addition of bicalutamide significantly improved objective progression-free survival (PFS) for patients with locally advanced disease, reducing the risk of progression by 34% versus standard care alone (hazard ratio 0.66; 95% confidence interval 0.55, 0.79; P<0.001). In localized disease, a significant difference in objective PFS was not found. There was no significant difference in overall survival.

Anilides↗

PubMed2006

Lectin binding studies on C-28/I2 and T/C-28a2 chondrocytes provide a basis for new tissue engineering and drug delivery perspectives in cartilage research.

The present study was performed to evaluate the applicability of plant lectins as mediators of bioadhesion in cartilage research using human chondrocyte cell lines C-28/I2 and T/C-28a2. The bioadhesive properties of fluorescein-labelled lectins with different carbohydrate specificities were investigated by flow cytometry. Specificity of the lectin-cell interactions was ascertained by competitive inhibition using complementary carbohydrates. As compared to that of other lectins, the interaction between wheat germ agglutinin (WGA) and chondrocytic cells was characterised by remarkable cytoadhesion, adequate binding strength and a high degree of specificity for N-acetyl-glucosamine as contained in hyaluronan chains. We therefore suggest WGA to be a promising candidate for mediating bioadhesion to low-adhesive scaffolds in cartilage tissue engineering. Moreover, the WGA-association rate of C-28/I2 and T/C-28a2 cells was dependent on temperature indicating cellular uptake of membrane-bound WGA. Intracellular enrichment was confirmed by confocal microscopy. Equilibration of intracellular pH gradients with monensin resulted in the reversal of quenching effects indicating accumulation of WGA within acid compartments of chondrocytic cells. Thus, WGA might be internalised into chondrocytes together with hyaluronan via the CD44 receptor-mediated endocytosis pathway and accumulated within lysosomes. This physiological process could represent a feasible pathway to target WGA-functionalised drug delivery devices into chondrocytes.

Acetylglucosamine↗

PubMed2006

Plasticity in the adult language system: a longitudinal electrophysiological study on second language learning.

Event-related potentials (ERPs) were used to trace changes in brain activity related to progress in second language learning. Twelve English-speaking exchange students learning German in Switzerland were recruited. ERPs to visually presented single words from the subjects' native language (English), second language (German) and an unknown language (Romansh) were measured before (day 1) and after (day 2) 5 months of intense German language learning. When comparing ERPs to German words from day 1 and day 2, we found topographic differences between 396 and 540 ms. These differences could be interpreted as a latency shift indicating faster processing of German words on day 2. Source analysis indicated that the topographic differences were accounted for by shorter activation of left inferior frontal gyrus (IFG) on day 2. In ERPs to English words, we found Global Field Power differences between 472 and 644 ms. This may due to memory traces related to English words being less easily activated on day 2. Alternatively, it might reflect the fact that--with German words becoming familiar on day 2--English words loose their oddball character and thus produce a weaker P300-like effect on day 2. In ERPs to Romansh words, no differences were observed. Our results reflect plasticity in the neuronal networks underlying second language acquisition. They indicate that with a higher level of second language proficiency, second language word processing is faster and requires shorter frontal activation. Thus, our results suggest that the reduced IFG activation found in previous fMRI studies might not reflect a generally lower activation but rather a shorter duration of activity.

Adult↗

PubMed2006

[Therapeutic options for hormone-refractory prostate cancer].

For a long time, hormone-refractory prostate cancer was regarded as a chemoresistant tumor. The introduction of taxanes has prompted a change in this opinion. For the first time treatment with 75 mg/m(2) docetaxel every 3 weeks has evidenced a survival benefit in a phase III trial (median survival of 18.9 months versus 16.5 months with mitoxantrone). Further advantages were improved pain reduction and quality of life. Neutropenia was foremost among the side effects. Docetaxel is currently the standard treatment for hormone-refractory prostate cancer. The morbidity of metastatic hormone-refractory prostate cancer is influenced by bone metastases. Pain is a prominent feature. Skeletal complications are frequent. Therapy with 4 mg zoledronic acid reduced skeletal complications significantly in comparison to placebo. The most pronounced effect is the reduction of pathological fractures. Side effects include flu-like symptoms, muscle pain, and edemas. Zoledronic acid also belongs to the standard treatment of hormone-refractory prostate cancer with bone metastases.

Androgen Antagonists↗

PubMed2006

Are bone scans necessary in men with low prostate specific antigen levels following localized therapy?

PURPOSE: The prostate specific antigen level at which to recommend a bone scan after treatment of early prostate cancer is controversial. We identified the incidence of bone metastases at varying prostate specific antigen levels in asymptomatic men following radical prostatectomy, radiation therapy and watchful waiting. MATERIALS AND METHODS: Data were obtained from the Early Prostate Cancer trial comparing placebo with bicalutamide in addition to standard care for localized prostate cancer. As part of the trial patients were required to have routine bone scans regardless of prostate specific antigen levels. The prostate specific antigen levels were divided into subgroups and the incidence of positive bone scans was calculated for each group. RESULTS: The incidence of positive bone scans in patients treated with watchful waiting and given bicalutamide or placebo was low (0.7% to 3.2%) at prostate specific antigen levels less than 20 ng/ml. At greater than this level the sample sizes were smaller but there was a significant increase in the incidence of positive bone scans. In the groups treated with radiation therapy or radical prostatectomy, regardless of the addition of bicalutamide, the incidence of positive bone scans was low (0.2% to 1.4%) at prostate specific antigen levels less than 5 ng/ml. The sample sizes were smaller at prostate specific antigen levels greater than 5 ng/ml so the results are harder to interpret. CONCLUSIONS: Bone scans can be confidently eliminated in the followup of patients with early prostate cancer after standard care of those with prostate specific antigen levels less than 5 ng/ml. This level can be increased to 20 ng/ml with caution in those patients treated with watchful waiting.

Androgen Antagonists↗

PubMed2006

[Acute abdominal pain due to a ventriculo-peritoneal shunt metastasis of an intracranial germ cell tumor].

INTRODUCTION: Extracranial metastases of pineal germinomas are rare. CASE REPORT: The case of a metastasis of a primary intracranial germ cell tumor via a temporary-ventriculo-peritoneal shunt as a cause of acute abdominal pain is reported. The germ cell tumor markers were useful in establishing the diagnosis. CONCLUSIONS: With an appropriate clinical history, intra-abdominal metastases via a temporary ventriculo-peritoneal shunt should be considered in the differential diagnosis of acute abdominal pain.

Abdomen, Acute↗

PubMed2006

[Interdisciplinary recommendations concerning the therapy for hormone-refractory prostatic carcinoma].

Therapy with Docetaxel for hormone-refractory prostatic carcinoma has for the first time led to an increase in the survival time. Docetaxel has become established as a standard therapy for his indication. Since hormone-refractory prostatic carcinoma is not uniformly defined and is thus for prognosis not a homogeneous entity, the prospects at the start of chemotherapy are uncertain. In the summer of 2005 these questions were addressed in an interdisciplinary consensus conference. It was agreed that the 3-week scheme with 75 mg/m (2) as standard and the indication for symptomatic patients were above question. Opinions differed with regard to the use of chemotherapy in asymptomatic patients. In addition, recommendations for the performance and monitoring of the therapy were formulated.

Antineoplastic Agents, Hormonal↗

PubMed2006

The role of toll-like receptors in the immune-adrenal crosstalk.

Sepsis and septic shock remain major health concerns worldwide, and rapid activation of adrenal steroid release is a key event in the organism's first line of defense during this form of severe illness. Toll-like receptors (TLRs) are critical in the early immune response upon bacterial infection, and recent data from our lab demonstrate a novel link between the innate immune system and the adrenal stress response mediated by TLRs. Glucocorticoids and TLRs regulate each other in a bidirectional way. Bacterial toxins acting through TLRs directly activate adrenocortical steroid release. TLR-2 and TLR-4 are expressed in human and mice adrenals and TLR-2 deficiency is associated with an impaired glucocorticoid response. Furthermore, TLR-2 deficiency in mice is associated with marked cellular alterations in adrenocortical tissue. TLR-2-deficient mice have an impaired adrenal corticosterone release following inflammatory stress induced by bacterial cell wall compounds. This defect appears to be associated with a decrease in systemic and intraadrenal cytokine expression. In conclusion, TLRs play a crucial role in the immune-adrenal crosstalk. This close functional relationship needs to be considered in the treatment of inflammatory diseases requiring an intact adrenal stress response.

Adrenal Cortex↗

PubMed2005

Bridging the gap--biocompatibility of microelectronic materials.

There is an increasing interest in cell-based microelectronic biosensors for high-throughput screening of new products from the biotech pipeline. This requires fundamental knowledge of the biocompatibility of the materials used as the growing support for the cells. Using monolayer-forming Caco-2 cells of human origin, the biocompatibility of silicon wafers coated with various metals, dielectrics and semiconductors was assessed. Besides microscopic inspection, proliferation of cells indicating viability as well as brush border enzyme activity indicating differentiation of adherent growing cells were chosen as parameters to estimate biocompatibility. The type of wafer used for deposition of the coating initially influences the biocompatibility of the final product. Whereas p-doped silicon was fully biocompatible, n-doped silicon reduced the proliferation of cells. Among the different coatings, Al and Ti even increased the cell growth as compared to glass. Culturing the cells for 6 days on coated wafers demonstrated that the differentiation of adhering cells on Ti- and ZrO2-coated wafers was comparable to glass, whereas coatings with Si3N4, Au, Al, and ITO reduced differentiation to 15-35%. In the cases of Au and Si3N4 this effect equilibrated with prolonged culturing. These results demonstrate the importance of a careful selection of the materials used for the production of cell-based biosensors.

Alkaline Phosphatase↗

PubMed2005

Risks and benefits of hormonal manipulation as monotherapy or adjuvant treatment in localised prostate cancer.

A round table meeting was held to discuss the role of hormonal therapy in localised prostate cancer. The findings of the group were that immediate hormonal therapy does not provide an overall survival advantage in localised and locally advanced prostate cancer. Bicalutamide can prolong disease free survival in patients with locally advanced prostate cancer, however it is important to underline that at this time it has not been shown to influence disease specific nor overall survival. It remains also unproven that early treatment is superior to treatment at progression. However, a trend towards decreased survival with bicalutamide was observed in low risk patients such as those with localised disease. In patients receiving bicalutamide, there were increased cardiovascular side-effects, in addition to the high incidence of gynaecomastia. Early hormonal therapy has to be balanced against such side-effects and the inevitable appearance of hormone refractory disease in patients who progress after hormonal therapy. Consequently, patients with localised, low risk disease are not considered appropriate candidates for hormonal therapy used either as mono-therapy or in the adjuvant setting.

Adult↗

PubMed2005

Bicalutamide ('Casodex') 150 mg in addition to standard care in patients with nonmetastatic prostate cancer: updated results from a randomised double-blind phase III study (median follow-up 5.1 y) in the early prostate cancer programme.

Trial 24 is one of three placebo-controlled trials within the ongoing bicalutamide ('Casodex') Early Prostate Cancer (EPC) programme evaluating bicalutamide 150 mg/day in addition to radical prostatectomy, radiotherapy or watchful waiting for T1b-4, any N, M0 prostate cancer. In Trial 24, at 5.1 y median follow-up, the addition of bicalutamide significantly (P < 0.0001) improved objective progression-free survival (PFS) and prostate-specific antigen PFS compared with standard care alone. There was no significant difference in overall survival (P = 0.746). In the context of the whole EPC programme, long-term bicalutamide is not appropriate for localised disease, yet provides advantages in delaying disease progression in patients with locally advanced prostate cancer.

Adult↗

PubMed2004

[The significance of comorbidity and age in radical prostatectomy].

The coexistence of another diagnosis beside the index disease under study is defined as comorbidity. Comorbidity increases with advancing age. In candidates for radical prostatectomy, two aspects of comorbidity are of interest: its association with perioperative complications and long-term survival. The Charlson score is the most extensively studied comorbidity classification for the prediction of long-term outcome. Several studies have identified this score as an independent prognostic factor in the prostate cancer setting. In addition to the Charlson score, data collected during the preoperative cardiopulmonary risk assessment may deliver information identifying patients with an increased long-term mortality risk. The meaningfulness of comorbidity in predicting overall mortality seems to be comparable to that of the Gleason score, the most important tumor-related predictor of survival in prostate cancer. The identification of prognostically relevant single conditions and the development of a "radical prostatectomy-specific" comorbidity classification might improve the stratification of candidates for radical prostatectomy in the future.

Adolescent↗

PubMed2004

Systematic development of a guideline for early detection of prostate cancer: the German way in the evidence gap.

OBJECTIVE: To develop an evidence-based guideline, helping physcians make prudent decisions about diagnostic care for men wishing to undergo examination for early detection of prostate cancer. METHODS: A guideline development group, comprised of twenty healthcare professionals, including urologists, clinical chemists, pathologists, geriatricians, epidemiologists, technicians and a member of a patient self-help group, systematically gathered, evaluated, and discussed the most recent research available on early detection of prostate cancer. Nominal group technique (NGT) was employed to facilitate the decision-making process. RESULTS: The NGT was sufficient to find a consensus among different medical disciplines in a timely fashion. A standardized guideline, containing a short version for physicians and a standardized patient information booklet, for nation-wide use was developed. CONCLUSIONS: Population-based screening is not favoured, instead information should be given to men in their 50-70s, to enable shared decision-making between physician and patient for or against PSA-based early detection of prostate cancer.

Germany↗

PubMed2004

Can n-3 PUFA reduce cardiac arrhythmias? Results of a clinical trial.

Dietary n-3 polyunsaturated fatty acids (PUFA) derived from fatty fish or fish oil may reduce the incidence of lethal myocardial infarction and sudden cardiac death. This might be due to a prevention of fatal cardiac arrhythmias. So far, however, only few clinical data are available being adequate to define indications for an antiarrhythmic treatment with n-3 PUFA. In a randomized, double-blind, placebo-controlled study 65 patients with cardiac arrhythmias without coronary heart disease or heart failure were subdivided into 2 groups. One group (n = 33) was supplemented with encapsulated fish oil (3g/day, equivalent to 1g/day of n-3 PUFA) over 6 months. The other group (n = 32) was given 3g/day of olive oil as placebo. In the fish oil group a decrease of serum triglycerides, total cholesterol, LDL cholesterol, plasma free fatty acids and thromboxane B2 as well as an increase of HDL cholesterol were observed. Moreover, a reduced incidence of atrial and ventricular premature complexes, couplets and triplets were documented. Accordingly, higher grades of Lown's classification switched to lower grades at the end of the dietary period. No changes were seen in the placebo group. The data indicate an antiarrhythmic action of n-3 PUFA under conditions of clinical practice which might help to explain the reduced incidence of fatal myocardial infarction and sudden cardiac death in cohorts on a fish-rich diet or supplemented with n-3 PUFA. Further studies elucidating the possible link between the reduced incidence of cardiac arrhythmias and sudden cardiac death by dietary intake of n-3 PUFA are warranted.

Adult↗

PubMed2004

Disposition and pharmacokinetics of temozolomide in rat.

1. Temozolomide, an imidazotetrazine derivative, is a cytotoxic alkylating agent of broad-spectrum antitumour activity. The absorption, metabolism, distribution and excretion of temozolomide have been investigated in male and female Sprague-Dawley and Long-Evans rats following single oral or intravenous dose administration of 200 mg m(-2) non-radiolabelled or (14)C-radiolabelled temozolomide. The distribution of (14)C-temozolomide was also evaluated by whole-body autoradiography in male Sprague-Dawley rats. Plasma concentrations of temozolomide and its active metabolite 3-methyl-(triazen-1-yl)imidazole-4-carboxamide (MTIC) were determined by high-performance liquid chromatography (HPLC) with ultraviolet detection. Plasma, urine and faeces were profiled by HPLC with radiochemical detection. 2. Temozolomide was rapidly and extensively (>90%) absorbed and widely distributed in tissues. The distribution pattern of radioactivity was gender independent. Penetration into the brain following oral or intravenous administration was 35-39% based on the brain/plasma AUC ratio. 3. Following intravenous or oral administration, temozolomide was primarily eliminated renally (75-85% of the dose) as either unchanged drug, a carboxylic acid analogue, AIC (a degradation product) and a highly polar unidentified peak. Biliary excretion was minimal (1.4-1.6%). The pharmacokinetics (oral versus intravenous) were similar and gender independent. The absolute oral availability was 96-100%. Temozolomide was rapidly eliminated (t(1/2) = 1.2 h) and converted to MTIC. 4. Systemic exposure to MTIC was about 2% that of temozolomide. Overall, the disposition of temozolomide in rats was similar to that observed in humans.

Administration, Oral↗

PubMed2003

Stabilisation and determination of the biological activity of L-asparaginase in poly(D,L-lactide-co-glycolide) nanospheres.

The preservation of biological activity of protein drugs in formulations is still a major challenge for successful drug delivery. The enzyme L-asparaginase, which exhibits a short in vivo half-life and is only active against leukaemia in its tetrameric form, was encapsulated in poly(D,L-lactide-co-glycolide) nanospheres by the (w/o)/w-emulsion solvent evaporation technique in presence of various potential stabilisers. Elucidation of the preparation steps revealed that the enzyme is denaturated at the aqueous/organic interface and by sonication. The preparation of L-asparaginase nanospheres with trehalose, PEG 400, and glycerol as components of the inner aqueous phase yielded colloidal formulations with increased biological activity as determined by an improved protocol for quantification of the active enzyme encapsulated. After lyophilisation the enzyme activity and particle size distribution were retained only by use of Pluronic F68 as a lyoprotectant. Despite the unaltered particle size and improved biological activity, the release profile of the enzyme was strongly altered by coencapsulation of the stabilisers resulting in increased first bursts. In consequence, the biological activity of L-asparaginase during preparation and storage can be improved by combining appropriate additives but concurrently the release profile is influenced.

Antineoplastic Agents↗

PubMed2003

[Gemcitabine/cisplatin vs. MVAC. 5 year survival outcome of the phase III study of chemotherapy of advanced urothelial carcinoma in Germany].

Of 405 patients with stage IV transitional cell carcinoma from an international multicenter phase III trial, 70 were randomized in Germany to receive either gemcitabine/cisplatin or standard MVAC systemic chemotherapy for locally advanced or metastatic urothelial cancer. Overall survival as the primary endpoint of the study was similar in both arms (median survival GC 15.4 months vs MVAC 16.1 months), as were tumor-specific survival and time to progressive disease. In the intent-to-treat analysis, the 5-year overall survival rate was 10% for patients randomized to GC and 18% randomized to MVAC. Tumor overall response rates (GC 54%, MVAC 53%) were similar. The toxic death rate was 0% in the GC arm and 3% (one patient) in the MVAC arm. Significantly more GC than MVAC patients experienced grade 3/4 anemia (GC 52%, MVAC 20%) with significantly more red blood cell transfusions in the GC arm.Significantly more GC than MVAC patients had grade 3/4 thrombocytopenia (GC 54%, MVAC 17%) without grade 3/4 hemorrhage or hematuria in either arm. More MVAC patients experienced grade 3/4 neutropenia (GC 56%, MVAC 61%, p=1.000), neutropenic or leukopenic fever (GC 0%, MVAC 10%, p=0.237), mucositis (GC 0%, MVAC 7%, p=0.495), and alopecia (GC 6%, MVAC 36%, p=0.004). GC represents a reasonable alternative for the palliative treatment of patients with locally advanced and metastatic transitional cell carcinoma. Sustained long-term survival was only found for patients with locally advanced cancer, lymphatic metastases, or solitary distant metastasis but not for visceral metastatic disease.

Adult↗