Biomedical subjects

Peter Schmid

Publications and source records attributed to Peter Schmid.

At least 37 records · Page 2Linked to original sources

PubMed2005

Ventricular myocardial architecture as visualised in postmortem swine hearts using magnetic resonance diffusion tensor imaging.

OBJECTIVE: The three-dimensional arrangement of the ventricular myocardial architecture remains controversial, in part because histological assessment is difficult to achieve, while anatomic dissections are, of necessity, destructive. In this study, we describe how the use of magnetic resonance diffusion tensor imaging has permitted us to reconstruct with precision the architecture of the ventricular myocardial fibres in the post-mortem swine heart. METHODS AND RESULTS: We obtained diffusion-weighted spin-echo measurements of autopsied porcine hearts using a whole body MR system. We calculated the diffusion tensor and the corresponding eigenvectors on a voxel-by-voxel basis. This permitted us to colour code the fibres, and reconstruct them by connecting voxels in direction of the largest eigenvector. Such reconstructions show that, in the middle layer of the left ventricle, most of the fibres have a circular orientation, albeit that a far from negligible component runs in a transverse direction. With increasing distance from the epicardium, the orientation of the fibres shows a continuous change in angulation with respect to an axis normal to the epicardium. CONCLUSION: Our data presented here supports the concept that the ventricular mass is arranged as a complex three-dimensional mesh of tangential and intruding fibres. The data offers no support for the concept of a "unique myocardial band". The method has the potential to detecting deviations from this basic normal architecture, being capable of reconstructing the ventricular mass so as to assess the spatial coordinates of any single fibre strand. The technique, therefore, has major potential clinical applications in the setting of the failing or malformed heart, potentially being able to identify either systematic or regional disarray of the myocardial fibres.

Animals↗

PubMed2005

Gemcitabine and mitoxantrone in metastatic breast cancer: a phase-I-study.

BACKGROUND: Gemcitabine and mitoxantrone are active agents for the treatment of metastatic breast cancer. Due to different modes of action and a favorable toxicity profile they are suitable for combination therapy. This phase I trial was initiated to determine the optimal doses for the combination in patients with metastatic breast cancer. Secondary objectives included the evaluation of the safety and efficacy of the regimen. PATIENTS AND METHODS: Patients with metastatic breast cancer were treated with gemcitabine (1000-1400 mg/m(2)) on days 1, 8 and 15 and mitoxantrone (10-14 mg/m(2)) on day 8. Treatment was repeated every 4 weeks for a maximum of 8 cycles. Doses were assigned at registration according to the escalation scheme. RESULTS: Twenty-six patients received a total of 93 cycles at 5 different dose levels. The maximum tolerated doses were 1200 mg/m(2) gemcitabine and 14 mg/m(2) mitoxantrone with grade 4 neutropenia being the dose limiting toxicity. Recommended phase II doses, however, are gemcitabine 1200 mg/m(2) and mitoxantrone 12 mg/m(2) based on a similar median dose intensity and a more favorable toxicity profile. Predominant toxicity was myelosuppression. Most common non-hematological toxicities were nausea, vomiting, alopecia and elevation of liver enzymes. Twenty-one patients were assessable for response. Four patients achieved a partial response accounting for an overall response rate of 19%. In addition, 12 patients (57%) had stable disease and 5 patients (24%) failed to response to the treatment. Median duration of response and duration of clinical benefit were 14 and 9 months, respectively. CONCLUSION: In this phase I study of gemcitabine and mitoxantrone, the DLT was neutropenia. Recommended phase II doses are gemcitabine 1200 mg/m(2) and mitoxantrone 12 mg/m(2).

Adult↗

PubMed2005

Prolonged infusion of gemcitabine in advanced solid tumors: a phase-I-study.

BACKGROUND: Gemcitabine is a pro-drug that has to be phosphorylated to gemcitabine-triphosphate in order to exhibit its antineoplastic activity. This reaction involves the enzyme deoxycytidine kinase which is saturated at plasma concentrations following standard 30-min infusions. Pharmacological studies indicate that prolonged administration of gemcitabine might result in higher intracellular concentrations of active metabolites. This phase I trial was therefore initiated to determine the optimal dose of gemcitabine administered over 4 h in patients with advanced solid tumors. PATIENTS AND METHODS: Patients were treated with gemcitabine as 4 h-infusion on day 1, 8 and 15 in 4 week intervals. The starting dose was 350 mg/m(2). Doses were escalated in 50 mg/m(2) increments. RESULTS: Twenty-one patients were treated at doses ranging from 350 to 450 mg/m(2). The maximum tolerated dose was 400 mg/m(2) with neutropenia, thrombocytopenia, stomatitis and elevation of liver enzymes being dose limiting toxicities (DLTs). Hematologic and nonhematological toxicities were generally mild to moderate. Most common side effects were myelosuppression, nausea, elevation of liver enzymes and asthenia. Objective responses were noted in patients with hepatocellular carcinoma and cholangio-carcinoma. CONCLUSION: In this phase I study of gemcitabine as 4h-infusion, DLTs were neutropenia, thrombocytopenia, stomatitis and elevation of liver enzymes. The recommended dose for phase II studies is 400 mg/m(2).

Adult↗

PubMed2005

Correlation of PCDD/F and PCB concentrations in soil samples from the Swiss soil monitoring network (NABO) to specific parameters of the observation sites.

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) and polychlorinated biphenyls (PCB) were determined in 23 soil samples collected at reference sites of the Swiss national soil monitoring network (NABO). Total PCDD/F and PCB concentrations are well correlated and proportional (R2=0.720). The total PCDD/F levels were between 72 and 703 ng/kg corresponding to 1.1-11 ng I-TEQ/kg, total PCB concentrations (sum of seven congeners IUPAC no. 28, 52, 101, 118, 138, 153, and 180) were from 1.1 to 12 microg/kg. In all samples, the PCDD/F and PCB concentrations were in the range of background levels for these contaminants in Central Europe. Ninteen samples revealed PCDD/F levels below the guide value of 5 ng I-TEQ/kg set by the Swiss ordinance relating to impacts on the soil (OIS); concentrations for the remaining four samples were below the trigger value (20 ng I-TEQ/kg). All PCB concentrations were below the guide value of 100 microg/kg. The elevated PCDD/F and PCB levels in some of the samples originating from forested sites could be attributed to the scavenging effect of forest canopies for semivolatile organic compounds. This interpretation could be substantiated by the observed distortion of the congener and homolog patterns of PCDD/F and PCB which is characteristic for forested sites.

Benzofurans↗

PubMed2005

Primary chemotherapy with gemcitabine, liposomal doxorubicin and docetaxel in patients with locally advanced breast cancer: results of a phase I trial.

The primary objective was to determine the optimal doses for gemcitabine (prolonged infusion), liposomal doxorubicin (Myocet) and docetaxel as primary (neoadjuvant) chemotherapy for locally advanced breast cancer. Secondary objectives included evaluation of the safety and efficacy of the regimen. Patients (n=19) with histologically confirmed stage II or III breast cancer were treated with liposomal doxorubicin (50-60 mg/m2) and docetaxel (60-75 mg/m2) on day 1, and gemcitabine as 4-h infusion (350-400 mg/m2) on day 4. Treatment was repeated every 3 weeks for a maximum of 6 cycles. The maximum tolerated doses were gemcitabine 350 mg/m2, liposomal doxorubicin 60 mg/m2 and docetaxel 75 mg/m2. Dose-limiting toxicities were stomatitis, diarrhea and infection. The predominant hematologic toxicity was mild-to-moderate myelosuppression with grade 3/4 neutropenia in 20% of cycles. Non-hematologic toxicity was generally mild, with no grade 4 toxicities being observed. Predominant non-hematologic toxicity was stomatitis, which occurred in 95% of patients. Grade 3 toxicities were reported for stomatitis, nausea, diarrhea, infection and constipation. No cases of cardiac, renal, pulmonary or neurotoxicity were observed. The clinical response rate was 83% and histologically confirmed, clinically complete remissions occurred in two patients (11%). We conclude that the combination of gemcitabine (prolonged infusion), liposomal doxorubicin and docetaxel is safe and highly effective in patients with locally advanced breast cancer as defined by maximum tolerated doses. The evaluated schedule is suitable for phase II studies.

Adult↗

PubMed2005

Proteasome: an emerging target for cancer therapy.

Proteasome inhibitors represent novel anti-cancer drugs which interact with the proteasome-ubiquitin pathway. The 26S proteasome is a multicatalytic threonine protease with three distinct catalytic activities. It is responsible for intracellular protein turnover in eukaryotic cells, including the processing and degradation of short- and some long-living proteins required for regulation of various cellular functions. Subsequently, the inhibition of the proteasomal function results in stabilization and accumulation of its substrates, which notably include cyclins, cyclin-dependent kinase inhibitors, transcriptional factors, tumor suppressor proteins and proto-oncogenes. This results in confounding signals in the cell inducing cell cycle arrest and activation of apoptotic programs. Acting on transcriptional factor NF-kappaB, which is upregulated in some tumors undergoing chemotherapy or irradiation and downregulated by proteasome inhibition, a significant chemosensitization and consequently synergistic effects concerning the anti-tumor activity could be achieved. Bortezomib is the first proteasome inhibitor that has entered clinical trials. In multiple myeloma, both the US Food and Drug Administration and European Medicine Evaluation Agency granted approval for the use of bortezomib (Velcade) for the treatment of multiple myeloma patients who have received at least two prior therapies and have demonstrated disease progression on the last therapy. At present, other trials examine the activity in a variety of solid tumors and hematological malignancies. This paper reviews preclinical and clinical results.

Animals↗

PubMed2004

Endocrine activity and developmental toxicity of cosmetic UV filters--an update.

UV filters represent a new class of endocrine active chemicals. In vitro, 8/9 chemicals showed estrogenic (MCF-7 cells), and 2/9 antiandrogenic activity (MDA-kb2 cells). Six/nine filters (benzophenone (Bp)-1, Bp-2, Bp-3, 3-benzylidene camphor (3-BC), 4-methylbenzylidene camphor (4-MBC), octyl-methoxycinnamate (OMC)) increased uterine weight in immature rats. 3-Benzylidene camphor and 4-MBC displaced 16alpha125I-estradiol from human estrogen receptor (ER)beta, not ERalpha. Developmental toxicity of 4-MBC (0.7-47 mg/kg body weight/day) and 3-BC (0.24-7 mg/kg), administered in chow was investigated in Long Evans (LE) rats. Weight gain of pregnant rats was reduced only by 3-BC, early postnatal survival rate and thymus weight by both compounds at higher doses. 4-Methylbenzylidene camphor and 3-BC delayed male puberty, and dose-dependently affected reproductive organ weights of adult male and female F1 offspring, with partly different effect patterns. Thyroid weight was increased by higher 4-MBC doses. Tissue-specific changes in mRNA levels of estrogen-regulated genes in prostate, uterus and brain regions, determined by real-time PCR, and in their response to acute estradiol challenge in adult gonadectomized offspring were observed. Lowest effective doses were 0.24 mg/kg/day for 3-BC and 7 mg/kg/day for 4-MBC. Fat tissue levels at 7 mg/kg 4-MBC (GC-MS) approached the range of UV filters in fish (Nagtegaal et al., 1997; Balmer et al., 2004).

Animals↗

PubMed2004

[Voluntariness and coercion in patients with schizophrenia].

OBJECTIVE: Associations between voluntariness of treatment, success of treatment, and number of hospital admissions should be examined. PATIENTS: 88 consecutive admissions with ICD-10 F2 disorders were assessed using the PANSS and the GAF at admission and discharge. Voluntariness was assessed regarding admission, hospital stay, medication, time of discharge, and treatment continuation in four degrees for each category. RESULTS: Voluntariness increased significantly with the number of hospital admissions in women. Outcome measures (PANSS and GAF differences admission/discharge and the respective differences divided by number of inpatient days) were not significantly related to any aspect of voluntariness. Voluntariness was negatively associated with PANSS-scores at admission, but not at discharge. Aggressive behaviour and coercive measures were observed more frequently in patients with aspects of involuntariness. CONCLUSION: The short-term success of treatment in acute schizophrenic episodes seems not to be affected by measures of compulsive treatment. There is some evidence that experiences with former inpatient treatment increase the degree of voluntariness in women.

Adolescent↗

PubMed2004

Effect of voluntariness of participation in treatment on short-term outcome of inpatients with schizophrenia.

OBJECTIVE: The purpose of this study was to examine associations between the voluntary or coercive nature of patients' participation in inpatient treatment and the short-term outcome of inpatient treatment for patients with schizophrenia. METHODS: Eighty-eight adult patients with schizophrenia and delusional disorders who were consecutively admitted to a 320-bed psychiatric hospital in southern Germany over a three-month period in 2002 were assessed with the Positive and Negative Syndrome Scale (PANSS) and the Global Assessment of Functioning (GAF) at admission and discharge, a mean of 36.2 days later. The patients were grouped by whether their participation was voluntary or involuntary in each of five aspects of inpatient treatment: admission, hospital stay, medication, discharge, and intention to continue treatment after discharge. Outcome was defined as the change between admission and discharge in scores on the PANSS and the GAF and change in those scores per inpatient day. RESULTS: The outcome measures were not significantly related to the voluntariness of patients' participation in any aspect of treatment. CONCLUSIONS: The short-term outcome of inpatient treatment is independent of whether treatment is voluntary.

Adolescent↗

PubMed2004

Effect of high-volume and -intensity endurance training in heart transplant recipients.

BACKGROUND: A recommended component of heart transplant recipients (HTR) is endurance-oriented exercise therapy. However, the trainability of HTR after transplantation is vague. We examined the effect of high-volume and -intensity exercise training on exercise performance in HTR, compared with HTR undergoing regular rehabilitation training, and sedentary healthy subjects (SHS). METHODS: We studied four groups of individuals; of those, three groups were HTR. Subjects were a regularly trained HTR group of denervated (HTR-D; N = 15), reinnervated (HTR-R; N = 26) hearts, a high-volume and -intensity endurance-training group (training time 7-20 h.wk(-1); HTR-ET; N = 12), and a group of sedentary healthy subjects (SHS; N = 21). All participants performed cardiopulmonary exercise testing. RESULTS: The HTR-ET achieved a significantly higher performance (255 +/- 47 W, VO(2max) of 45.2 +/- 6.9 mL.kg(-1).min(-1)) in contrast to all other groups (HTR-D: 119 +/- 17 W, VO(2max) of 17.4 +/- 4.5 mL.kg(-1).min(-1); HTR-R: 119 +/- 17 W, VO(2max) of 16.9 +/- 3.7 mL.kg(-1).min(-1); SHS: 184 +/- 19 W, VO(2max) of 35.0 +/- 6.9 mL.kg(-1).min(-1)). The HR at maximal power output in the HTR-ET was 169 +/- 17 bpm and similar to SHS (164 +/- 17 bpm), but significantly higher than HTR-D (125 +/- 16) and HTR-R (142 +/- 10). Maximal lactate concentration (LAmax) of HTR-ET was 9.9 +/- 2.2 mmol.L(-1), comparable to SHS (9.2 +/- 2.1 mmol.L(-1)), and significantly higher than HTR-D (5.5 +/- 1.5 mmol.L(-1)) and HTR-R (5.1 +/- 1.0 mmol.L(-1)). CONCLUSIONS: Data suggest that HTR can perform high-volume and -intensity exercise training, reaching exercise performance comparable to or even exceeding values of sedentary or moderately trained healthy subjects.

Adult↗

PubMed2003

Biochemical identification of proteasome-associated endonuclease activity in sunflower.

Proteasomes have been purified from sunflower hypocotyles. They elute with a molecular mass of 600 kDa from gel filtration columns and two-dimensional gel electrophoresis indicates that the complex contains at least 20 different protein subunits. Peptide microsequencing revealed the presence of four subunits homologous to subunits Beta2, Beta6, Alpha5 and Alpha6 of plant proteasomes. These proteasomes have chymotrypsin-like activity and the highly purified fraction of this complex is associated with an endonuclease activity hydrolyzing Tobacco mosaic virus RNA and Lettuce mosaic virus RNA with a cleavage pattern showing fragments of well-defined size. This is the first evidence of a RNA endonuclease activity associated with plant proteasomes.

Amino Acid Sequence↗

PubMed2003

Polybrominated diphenyl ethers in whitefish from Swiss lakes and farmed rainbow trout.

A method for trace analysis of polybrominated diphenyl ethers (PBDE) in fish based on gas chromatography/electron ionization high resolution mass spectrometry (GC/EI-HRMS) was developed, and levels of PBDE were determined in whitefish (Coregonus sp.) from eight Swiss lakes and in rainbow trout (Oncorhynchus mykiss) from four Swiss fish farms. PBDE concentrations (sum of PBDE congeners BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) in filet from whitefish between 36 and 165 ng/g lipid weight (lw) were found, corresponding to wet weight (ww) concentrations of 1.6-7.4 ng/gww. PBDE contents in filet from farmed rainbow trout were significantly lower than in wild whitefish (12-24 ng/glw, 0.74-1.3 ng/gww), and the PBDE congener patterns were different for both species (a higher BDE-47 to BDE-99 ratio for farmed rainbow trout compared to wild whitefish was found). Whitefish PBDE levels [ng/glw] correlate better with the surface/volume ratio of the respective lakes (r(2)=0.70) than with other lake properties such as catchment area (size or number of inhabitants) or residence time, suggesting atmospheric deposition as an input pathway for PBDE. Based on an average daily consumption of 20 g whitefish (Switzerland) with a PBDE content of 7.4 ng/gww (highest PBDE concentration detected in this study), a maximum daily intake of 0.15 microg PBDE was estimated (0.026 microg/day for farmed trout). This number corresponds to the lower end of the estimate for the total PBDE intake of the Nordic consumer of 0.2-0.7 microg/day.

Animals↗

PubMed2003

Temporal and local trends of PCDD/F levels in cow's milk in Switzerland.

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) were determined in 30 Swiss cow's milk samples collected at dairy farms in the vicinity to point sources, in rural/alpine areas distant to known sources, and from tanks in large industrial milk processing plants. The contaminant concentrations in samples collected in 2001 were compared to data from analyses conducted in 1984 and 1990/1991 at the same sites. In 2001, the PCDD/F levels in milk from farms near point sources (0.63+/-0.26 ng I-TEQ/kg milk fat) are slightly but significantly higher in than milk from remote areas (0.36+/-0.09 ng I-TEQ/kg milk fat). Consumer milk collected at the processing plants had intermediary levels (0.51+/-0.19 ng I-TEQ/kg milk fat). However, milk in 2001 was significantly less contaminated than the samples collected in 1990/1991 and 1984. This trend is particularly pronounced near point sources but is also apparent in consumer milk and milk from remote areas. No geographical gradient in the atmospheric input of PCDD/F in Switzerland was found. The reduction in PCDD/F levels in dairy milk is paralleled by and correlated to the remediation of known PCDD/F emitting industries, as enforced by federal authorities.

Air Pollutants↗

PubMed2002

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in food of animal origin. The Swiss dioxin monitoring program.

Between 1997 and 1999, several cases of dioxin contaminations in foodstuffs of animal origin occurred in Europe due to feed contaminated by several independent sources: citrus pulp pellets, fat containing polychlorinated biphenyls (PCB), and kaolinitic clay as anti-caking agent in feedingstuffs. As a consequence of the latter, a survey on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in food of animal origin was initiated by the Swiss authorities to assess the extent of PCDD/F contamination and to document the efficiency of the measures taken to ensure the decontamination of the food supply. Investigation of a total of 128 samples of cow's milk, poultry, eggs, and meat revealed several cases of residue levels distinctly above the background exposure limit of approximately 2.5 ng of I-TEQ/kg (fat basis). Particularly, elevated concentrations were found in eggs (maximum 13 ng of I-TEQ/kg), poultry (maximum 3.9 ng of I-TEQ/kg), and pork (maximum 7.5 ng of I-TEQ/kg). On the basis of the observed PCDD/F congener pattern, the contamination could be attributed to PCDD/F-contaminated kaolin that was used as an anti-caking agent in particular feedstuffs.

Animal Feed↗

PubMed2002

Austrian Moderate Altitude Study 2000 (AMAS 2000). The effects of moderate altitude (1,700 m) on cardiovascular and metabolic variables in patients with metabolic syndrome.

We investigated the changes in the cardiovascular system [resting blood pressure (BP) and heart rate (HR), measured by means of a 24-h ambulatory BP and a holter-electrocardiogram (ECG)], glycemic parameters, and lipid metabolism of subjects suffering from metabolic syndrome during a 3-week sojourn at 1,700 m in the Austrian Alps. A total of 22 male subjects with metabolic syndrome were selected. Baseline investigations were performed at Innsbruck (500 m above sea level). During the 3-week altitude stay the participants simulated a holiday with moderate sports activities. Examinations were performed on days 1, 4, 9, and 19. After returning to Innsbruck, post-altitude examinations were conducted after 7-10 days and 6-7 weeks, respectively. The 24-h ambulatory BP and holter ECG revealed a decrease in average HR, BP, and rate pressure product (RPP: systolic blood pressure x HR) after 3 weeks of altitude exposure. In some patients, an increase in premature ventricular beats was observed at the end compared to the beginning of the exposure to moderate altitude. The ECG revealed no ischemic ST-segment changes. Maximal physical capacity as measured by symptom-limited maximal cycle ergometry tests remained unchanged during the study. Six weeks after the altitude exposure the blood pressure increased again and returned to pretest levels. The Homeostasis Model Assessment index, which is a measure of insulin resistance, decreased significantly and glucose concentrations obtained after an oral glucose tolerance test were significantly lower after the stay at altitude compared to the basal values. We conclude that after a 3-week exposure to moderate altitude, patients with metabolic syndrome (1) tolerated their sojourn without any physical problems, (2) exhibited short-term favorable effects on the cardiovascular system, and (3) had significant improvements in glycemic parameters that were paralleled by a significant increase in high-density-lipoprotein-cholesterol.

Adaptation, Physiological↗

PubMed2002

[High-dose chemotherapy in breast cancer].

BACKGROUND: The role of high-dose chemotherapy (HDCT) in primary and metastatic breast cancer remains controversial. Although results of several randomized trials have become available, the data is still inconclusive. ADJUVANT HDCT: In the adjuvant setting, only one trial has shown an advantage in recurrence-free survival, whereas none of the randomized trials showed a significant improvement in overall survival. HDCT FOR STAGE IV DISEASE: In metastatic breast cancer, four of five randomized trials revealed a significant benefit in progression-free survival for patients treated with HDCT. However, differences in overall survival have not been observed. INTERPRETATION OF TRIALS: Interpretation of the trials is limited due to a lack of statistical power in some of the trials, a relatively short follow-up, a relatively intensive chemotherapy regimen in the control arm, and an inappropriate selection of cytotoxic agents with only moderate activity and/or unacceptable toxicity. CONCLUSION: Several questions, especially the approach of early intensification or tandem HDCT, have to be answered yet. The results of ongoing studies are urgently needed.

Adult↗

PubMed2002

The combination of fludarabine and cyclophosphamide results in a high remission rate with moderate toxicity in low-grade non-Hodgkin's lymphomas.

We undertook a prospective study to evaluate the role of the combination of fludarabine and cyclophosphamide in patients with low-grade non-Hodgkin's lymphoma. Twenty-seven patients with low-grade non-Hodgkin's lymphoma were treated with i.v. fludarabine (30 mg/m ) and cyclophosphamide (250 mg/m ) on days 1-3. Cycles were given at 4-week intervals for a maximum of six courses. Fourteen patients (52%) were previously untreated, 13 patients (48%) had been treated with at least one chemotherapy regimen before. Of the 27 patients, 11 (41%) obtained a complete and 13 (48%) a partial remission, thus the overall response rate was 89%. The remission rate in untreated patients was slightly higher than in pretreated patients (93 versus 85%). The toxicity was mild, no treatment-related mortality occurred. Neutropenia was the most common side effect, grade 4 neutropenia of rather short duration was observed in less than 7% of the cycles. At the end of the treatment, the mean CD4 count was 155/ l and the mean CD8 count 204/ l. Severe infections did not occur. These results show that the combination of fludarabine and cyclophosphamide in the doses used in this study is an effective regimen with manageable toxicity in low-grade non-Hodgkin's lymphoma.

Adult↗

PubMed2002

Interactions of antioestrogens and aromatase inhibitors.

Aromatase inhibitors and antioestrogens have shown substantial activity in primary and advanced breast cancer. Since they exhibit different modes of action, attempts have been made to combine them or to use them sequentially in order to potentially increase their efficacy. In preclinical studies, combined, sequential or alternating treatments with aromatase inhibitors and antioestrogens have failed to provide higher antitumoural activity. There are relevant pharmacokinetic interactions resulting in decreased plasma concentrations of third generation aromatase inhibitors when combined with tamoxifen. Several randomised clinical trials comparing single agent and combined treatment with tamoxifen and aminoglutethimide failed to show any benefit for the combination. Early results of the adjuvant ATAC trial indicate that single agent anastrozole is superior to tamoxifen or the combination of both. Several trials are ongoing which might help to further define the role of sequential or combined treatment with aromatase inhibitors and antioestrogens. However, to date, looking at the current evidence, combined treatment with aromatase inhibitors and antioestrogens does not appear to provide additional benefit compared to single agent treatment.

Antineoplastic Agents↗