Different classes of EGFR inhibitors may have different potential to improve local tumour control after fractionated irradiation: a study on C225 in FaDu hSCC

BACKGROUND AND PURPOSE

Previous experiments reported from this laboratory have shown that simultaneous application of the selective epidermal growth factor receptor tyrosine kinase (EGFR-TK) inhibitor BIBX1382BS during fractionated irradiation significantly prolonged growth delay of FaDu human squamous cell carcinoma but did not improve local tumour control. The present study investigates the effect of the EGFR monoclonal antibody (mAb) C225 on local tumour control of FaDu tumours after combined treatment with single dose and fractionated irradiation to address whether different classes of EGFR inhibitors have different potential to improve the outcome of radiotherapy in the same tumour model.

MATERIAL AND METHODS

In unirradiated tumours, C225 was given either once or 4 times i.p. to the nude mice. Irradiation experiments were performed with graded single doses under clamp hypoxic conditions or with 30 fractions in 6 weeks with graded total doses under ambient blood flow. C225 was given 6h before or 6 h before and 2, 5 and 7 days after single dose irradiation. During fractionated irradiation C225 was given once per week. Experimental endpoints were tumour growth delay and local tumour control 120 after end of irradiation.

RESULTS

C225 treatment resulted in prolongation of tumour growth delay after drug treatment alone as well as after single dose and fractionated irradiation. TCD50 values were reduced from 56.3 Gy [95% CI 50; 62 Gy] after single dose irradiation alone to 46.0 Gy [41;51] (enhancement ratio [ER]=1.22, P<0.01) after 1 C225 injection and 47.7 Gy [44; 51] after 4 injections of the drug (ER=1.18, P=0.06). After fractionated irradiation, tumour control dose 50% (TCD50) was 73.0 Gy [64; 82] in control tumours and 63.1 Gy [57; 69] after simultaneous C225 treatment, corresponding to an ER of 1.2 (P=0.01).

CONCLUSION

Treatment of FaDu hSCC with the anti-EGFR mAb C225 resulted in a significant prolongation of tumour growth delay after single dose and fractionated irradiation. In contrast to previous results on the EGFR-TK inhibitor BIBX1382BS, this prolongation of growth delay translated into a slight but significant improvement of local tumour control. The data indicate that different classes of EGFR inhibitors may have different potential to improve the outcome of radiotherapy in the same tumour model.

Quality of life and attitudes towards psychotropics and dependency: consumers vs. non-consumers aged 50 and over

AIM

To assess the relationships between socio-demographic factors, quality of life and attitudes towards psychotropic drugs and dependency and to compare those relationships in continuous consumers (CC), occasional consumers (OC) and non-consumers (NC) of those drugs.

METHODS

Quality of life (SF36) and attitudes (14 statements) were measured in 601 subjects (45-60 years old) from the SUVIMAX cohort (SUpplementation en VItamines et en sels Mineraux AntioXydants). Data were obtained on 334 NC, 142 CC, 125 OC from the inclusion questionnaire and the monthly consumption report notebooks kept by subjects between 1994 and 1998. Dichotomous and polychotomous logistic regressions were used for the analysis.

RESULTS

The lower the quality of life score the more frequent was consumption. NC tended to be men, with high quality of life scores. They entertained negative attitudes towards psychotropics and dependency. OC tended to be women reporting a chronic pathology, with fairly high social status. They had intermediate quality of life and denied dependency. CC tended to be men with no professional activity and low quality of life scores in particular for mental health and perceived health. They had positive attitudes towards psychotropics and accept dependency.

DISCUSSION

Assessment of patients' quality of life and understanding of their attitudes towards psychotropics can provide essential information for those in charge of health promotion programmes and may help in identifying new intervention strategies. Preventive education and follow-up of therapy may be better suited to the needs of patients.

Palpation imaging using a haptic system for virtual reality applications in medicine

In the field of medical diagnosis, there is a strong need to determine mechanical properties of biological tissue, which are of histological and pathological relevance. Malignant tumors are significantly stiffer than surrounding healthy tissue. One of the established diagnosis procedures is the palpation of body organs and tissue. Palpation is used to measure swelling, detect bone fracture, find and measure pulse, or to locate changes in the pathological state of tissue and organs. Current medical practice routinely uses sophisticated diagnostic tests through magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US) imaging. However, they cannot provide direct measure of tissue elasticity. Last year we presented the concept of the first haptic sensor actuator system to visualize and reconstruct mechanical properties of tissue using ultrasonic elastography and a haptic display with electrorheological fluids. We developed a real time strain imaging system for tumor diagnosis. It allows biopsies simultaneously to conventional ultrasound B-Mode and strain imaging investigations. We deduce the relative mechanical properties by using finite element simulations and numerical solution models solving the inverse problem. Various modifications on the haptic sensor actuator system have been investigated. This haptic system has the potential of inducing real time substantial forces, using a compact lightweight mechanism which can be applied to numerous areas including intraoperative navigation, telemedicine, teaching and telecommunication.

Which patients benefit from hemodialysis therapy in hepatorenal syndrome?

BACKGROUND AND AIM

Hepatorenal syndrome (HRS) occurs in patients with advanced liver cirrhosis and has a poor outcome. The aim of the present study was to investigate which patients with HRS are likely to benefit from hemodialysis.

METHODS

Data were collected prospectively from 30 patients with Child-Pugh C liver cirrhosis and HRS. Patients were either treated with continuous veno-venous hemodialysis (CVVHD) if they were mechanically ventilated, or with intermittent hemodialysis (HD) if they were not mechanically ventilated. Prognosis was assessed by the Child-Pugh and by the Model for End-Stage Liver Disease (MELD) score. The primary aim of the study was the analysis of overall and 30-day patient survival during hemodialysis therapy. To identify predictive factors of survival, variables obtained before the initiation of dialysis therapy were evaluated.

RESULTS

Patients' 30-day survival was 8/30 (median survival time 21 days). Among patients treated with mechanical ventilation, 30-day survival time was 0/15 while 8/15 patients without mechanical ventilation survived more than 30 days (P < 0.001). Using a multivariate model, the relative hazards for serum albumin, international normalized ratio (INR) and catecholamine therapy were not different from one another (P > 0.05), indicating that these parameters were not independent predictors of survival. Mechanical ventilation was an independent risk factor for 30-day (relative hazard 6.6 [1.6-27.7], P < 0.001) and overall survival (relative hazard 6.3 [1.5-26.5], P = 0.01). Child-Pugh (P < 0.01) and the MELD (P < 0.01) score were predictive for overall survival independent of mechanical ventilation.

CONCLUSIONS

Patients with HRS without mechanical ventilation may benefit from hemodialysis, whereas hemodialysis seems to be futile in patients with mechanical ventilation.

Are there more than cross-sectional relationships of social support and support networks with functional limitations and psychological distress in early rheumatoid arthritis? The European Research on Incapacitating Diseases and Social Support Longitudinal

OBJECTIVE

To investigate whether greater social support and support network are cross-sectionally associated with less functional limitations and psychological distress in patients with early rheumatoid arthritis (RA); whether this association is constant over time; and whether increases in social support or support network are associated with less functional limitations and psychological distress.

METHODS

Subjects were from the European Research on Incapacitating Diseases and Social Support cohort and had early RA. Social support, support network, functional limitations (Health Assessment Questionnaire), and psychological distress (General Health Questionnaire) were assessed annually. Variance and covariance analyses with repeated measures were performed.

RESULTS

A total of 542 subjects were assessed for 3 years. On average, patients with a greater amount of specific social support or a stronger specific support network experienced less functional limitation and less psychological distress. Changes in a given subject's functional limitations and psychological distress did not depend on his or her baseline social support or support network. Neither social support nor support network change over time.

CONCLUSION

There may be a cross-sectional link between specific social support or support network and functional limitations and psychological distress, but no longitudinal association could be evidenced.

Adjuvant inhibition of the epidermal growth factor receptor after fractionated irradiation of FaDu human squamous cell carcinoma

BACKGROUND AND PURPOSE

Experiments performed by others have shown that inhibition of EGFR before and after single dose irradiation prolonged growth delay and improved local tumour control. This suggests that adjuvant EGFR inhibition can inactivate clonogens that survived irradiation. To test this hypothesis local tumour control was investigated after fractionated radiotherapy and adjuvant EGFR-TK inhibition.

MATERIALS AND METHODS

FaDu hSCC xenografts were irradiated with 30 fractions in 6 weeks with total doses of 30-100Gy. After the end of fractionated irradiation, BIBX1382BS was administered daily orally over a time period of 75 days. Tumour volumes were determined two times per week, the volume doubling time during adjuvant treatment was calculated for progressing and recurrent tumours. Local tumour control was investigated 120 days after end of irradiation.

RESULTS

Adjuvant BIBX1382BS significantly reduced the tumour growth rate but did not improve local tumour control. The TCD(50) values were 66.1Gy (95% C.I.: 59; 73Gy) after adjuvant BIBX1382BS treatment and 67.9Gy (61; 75Gy) for control tumours (P=0.9).

CONCLUSIONS

These data indicate that, although growth of recurrent tumour cells after irradiation is dependent on the EGFR pathway, tumour cells retain their clonogenic potential despite of EGFR inhibition. The results imply also that a decreased tumour growth rate does not necessarily allow conclusions on enhanced inactivation of clonogenic cells when antiproliferative drugs are combined with radiation.

Effect of buffered formalin on amplification of DNA from paraffin wax embedded small biopsies using real-time PCR

BACKGROUND

The isolation of good quality DNA from routinely fixed and processed biopsy samples is crucial for the success of subsequent molecular analysis.

AIMS

To compare the amount of beta actin DNA extracted from upper gastrointestinal tract biopsies fixed in buffered and unbuffered formalin.

METHODS

Amounts of beta actin DNA extracted from forceps biopsies of the upper gastrointestinal tract fixed in unbuffered (n = 22) and buffered formalin (n = 16) were estimated by quantitative real-time polymerase chain reaction.

RESULTS

The yield of beta actin DNA was significantly higher in biopsies fixed in buffered formalin than in those fixed in unbuffered formalin (median 2.8 x 10(4) and 5.3 x 10(2) DNA molecules, respectively; p < 0.005). Furthermore, fixation in buffered formalin led to a more reproducible DNA extraction, as indicated by the coefficient of variation (1.0 and 2.2, respectively).

CONCLUSIONS

This study indicates that tissue samples should be fixed in buffered formalin to facilitate the use of molecular pathology analysis in routine biopsy material.

Molecular analysis of nicotinic receptor expression in autism

Autism is a developmental disorder of unknown aetiopathology and lacking any specific pharmacological therapeutic intervention. Neurotransmitters such as serotonin, gamma-aminobutyric acid (GABA) and acetylcholine have been implicated. Abnormalities in nicotinic acetylcholine receptors have been identified including cortical loss of binding to the alpha4/beta2 subtype and increase in cerebellar alpha7 binding. Receptor expression (mRNA) has not so far been systematically examined. This study aims to further explore the role of nicotinic receptors in autism by analysing nicotinic receptor subunit mRNA in conjunction with protein levels and receptor binding in different brain areas. Quantitative RT-PCR for alpha4, alpha7 and beta2 subunit mRNA expression levels; alpha3, alpha4, alpha7 and beta2 subunit protein expression immunochemistry and specific radioligand receptor binding were performed in adult autism and control brain samples from cerebral cortex and cerebellum. Alpha4 and beta2 protein expression and receptor binding density as well as alpha4 mRNA levels were lower in parietal cortex in autism, while alpha7 did not change for any of these parameters. In cerebellum, alpha4 mRNA expression was increased, whereas subunit protein and receptor levels were decreased. Alpha7 receptor binding in cerebellum was increased alongside non-significant elevations in mRNA and protein expression levels. No significant changes were found for beta2 in cerebellum. The data obtained, using complementary measures of receptor expression, indicate that reduced gene expression of the alpha4beta2 nicotinic receptor in the cerebral cortex is a major feature of the neurochemical pathology of autism, whilst post-transcriptional abnormalities of both this and the alpha7 subtype are apparent in the cerebellum. The findings point to dendritic and/or synaptic nicotinic receptor abnormalities that may relate to disruptions in cerebral circuitry development.

Diagnostic and prognostic evaluation of left ventricular systolic heart failure by plasma N-terminal pro-brain natriuretic peptide concentrations in a large sample of the general population

OBJECTIVE

To evaluate N-terminal pro-brain natriuretic peptide (NT-proBNP) as a diagnostic and prognostic marker for systolic heart failure in the general population.

DESIGN

Study participants, randomly selected to be representative of the background population, filled in a heart failure questionnaire and underwent pulse and blood pressure measurements, electrocardiography, echocardiography, and blood sampling and were followed up for a median (range) period of 805 (60-1171) days.

SETTING

Participants were recruited from four randomly selected general practitioners and were examined in a Copenhagen university hospital.

PATIENTS

382 women and 290 men in four age groups (50-59 (n = 174); 60-69 (n = 204); 70-79 (n = 174); > or = 80 years (n = 120)).

MAIN OUTCOME MEASURES

Value of NT-proBNP in evaluating patients with symptoms of heart failure and impaired left ventricular (LV) systolic function; prognostic value of NT-proBNP for mortality and hospital admissions.

RESULTS

In 38 (5.6%) participants LV ejection fraction (LVEF) was < or = 40%. NT-proBNP identified patients with symptoms of heart failure and LVEF < or = 40% with a sensitivity of 0.92, a specificity of 0.86, positive and negative predictive values of 0.11 and 1.00, and area under the curve of 0.94. NT-proBNP was the strongest independent predictor of mortality (hazard ratio (HR) = 5.70, p < 0.0001), hospital admissions for heart failure (HR = 13.83, p < 0.0001), and other cardiac admissions (HR = 3.69, p < 0.0001). Mortality (26 v 6, p = 0.0003), heart failure admissions (18 v 2, p = 0.0002), and admissions for other cardiac causes (44 v 13, p < 0.0001) were significantly higher in patients with NT-proBNP above the study median (32.5 pmol/l).

CONCLUSIONS

Measurement of NT-proBNP may be useful as a screening tool for systolic heart failure in the general population.

Repopulation of moderately well-differentiated and keratinizing GL human squamous cell carcinomas growing in nude mice

PURPOSE

It has been suggested that, reminiscent of the regulated proliferative response of normal squamous epithelium, squamous cell carcinomas that have preserved characteristics of differentiation have a greater repopulation capacity during fractionated irradiation than undifferentiated tumors. The aim of the present study was to investigate repopulation in moderately well-differentiated and keratinizing GL human squamous cell carcinomas in nude mice.

METHODS AND MATERIALS

GL human squamous cell carcinomas were transplanted s.c. into the right hind leg of NMRI nu/nu mice. Irradiation was performed with 5.4 Gy fractions under clamp hypoxia or with 2 Gy fractions under ambient conditions. Six, 12, or 18 fractions were given daily, every second day, or every third day. Graded top-up doses were applied under clamp hypoxia to determine the tumor control dose 50% (TCD(50)). A total of 20 TCD(50) assays were performed and analyzed using maximum-likelihood techniques.

RESULTS

With an increasing number of daily 5.4 Gy fractions under clamp hypoxia, the top-up TCD(50) values decreased significantly from 50.9 Gy (95% CI: 47, 54) after single doses to 0 Gy after 18 fractions. For the same number of fractions, the top-up TCD(50) increased with increasing overall treatment time. The results are consistent with a constant repopulation rate with a clonogenic doubling time (T(clon)) of 12.7 days (8.6, 16.8). Under ambient blood flow, the top-up TCD(50)s for daily 2 Gy fractions decreased significantly, but were less pronounced than for 5.4 Gy fractions under clamp hypoxia. For a given number of fractions under ambient conditions, the top-up TCD(50)s did not increase significantly with overall treatment time, except for irradiation with 12 fractions in 36 days compared to 12 and 24 days. The T(clon) value from these data was 24.0 days (11.6, 36.4).

CONCLUSION

Our data demonstrate a slow but significant rate of repopulation of clonogenic tumor cells during fractionated irradiation of GL human squamous cell carcinomas under clamp hypoxia without indication of a change of the repopulation rate during treatment. Less pronounced repopulation was observed for irradiation under ambient conditions, which might be explained by preferential survival of hypoxic and therefore nonproliferating cells. Taken together with our previous studies on poorly differentiated FaDu tumors (Petersen et al., IJROBP 2001;51:483-493), the results support important heterogeneity of kinetics and mechanisms of repopulation, in particular of the influence of the oxygenation status of surviving clonogenic cells on the repopulation rate during fractionated irradiation, in different experimental squamous cell carcinoma.

Sustained elevation of NF-kappaB DNA binding activity in radiation-induced lung damage in rats

PURPOSE

To characterize the cellular distribution and DNA binding activity of the nuclear factor kappaB (NF-KappaB) in a model of radiation-induced lung damage in the rat.

MATERIAL AND METHODS

The right lung of Fischer rats was irradiated with a single dose of 20 Gy. The cellular distributions of NF-KappaB proteins and mRNA were detected with immunohistochemistry and in-situ hybridization respectively. The DNA binding activity of NF-KappaB, nuclear and cytoplasmic levels of NF-KappaB proteins, and kinase activity towards IkappaBalpha (IKappaBAlpha) were determined using electrophoretic mobility shift assays (EMSA), Western blots and kinase assays, respectively. The mRNA level of interleukin 6 (IL-6) was determined using quantitative room temperature polymerase chain reaction.

RESULTS

There was a continuous elevation of NF-KappaB DNA binding activity in the rat lung after ionizing irradiation over 6 months. The irradiated lung tissue exhibited an increased kinase activity towards IKappaBAlpha and a selective loss of nuclear IKappaBAlpha. The NF-KappaB-DNA binding complex switched from p50-p65 heterodimers in normal lung tissue to p50 homodimers in irradiated lung tissue. The increased level of IL-6 mRNA suggests transcriptional activation of NF-KappaB-dependent genes in the irradiated rat lung.

CONCLUSIONS

The DNA binding activity of NF-KappaB is continuously activated after irradiation of the rat lung by loss of nuclear IKappaBAlpha. This might play a role in sustaining chronic inflammation and hyperproliferation of mesenchymal cells after irradiation.

Updated European core curriculum for radiotherapists (radiation oncologists). Recommended curriculum for the specialist training of medical practitioners in radiotherapy (radiation oncology) within Europe

AIM

To produce updated state-of-the-art recommendations for harmonised medical specialist training in radiotherapy within Europe.

MATERIAL AND METHODS

The Minimum Curriculum for the Theoretical Education in Radiation Oncology in Europe from 1991 was updated under consideration of new developments in medicine in general, and in radiotherapy and its basic sciences in particular. Recent medical developments, national guidelines and training programmes from European countries, as well as equivalent documents from the USA and Australia were reviewed by an expert panel jointly appointed by the European Society of Therapeutic Radiology and Oncology and the European Board of Radiotherapy. A draft document prepared by this group was circulated among the national and professional societies for radiotherapy in Europe for review before a European consensus conference took place in Brussels in December 2002.

RESULTS

The updated European Core Curriculum for Radiotherapists (Radiation Oncologists) was endorsed by representatives of 35 European nations during the Brussels consensus conference on December 14, 2002. Compared to the earlier version the updated document contains specific recommendations not only for the 5 year training curriculum but also for organisatoric and infrastructural aspects of teaching departments, and for supplementation of the training by formal teaching courses.

CONCLUSION

The updated European core curriculum is an important step on the way to fully harmonise medical specialist training in Europe and to guarantee equal access for all European citizens to highest quality medical care. The responsibility for the implementation of the standards and guidelines set in the updated Core Curriculum for radiotherapy (radiation oncology) will lie with the local and/or national training bodies and authorities.

Lateral Spreading of Topically Applied UV Filter Substances Investigated by Tape Stripping

The lateral spreading of topically applied substances is a competitive process to the penetration into the stratum corneum (SC). The penetration of topically applied UV filter substances into the human SC and the lateral spreading were investigated in vivo. Tape stripping in combination with spectroscopic measurements was used to study both processes of two UV filter substances. The concentration of both UV filters was determined inside and outside the application area by varying the application and tape stripping protocol. A spreading of the topically applied substances from the treated to the untreated areas was observed, which caused a concentration gradient. This lateral spreading depends on the time between application and tape stripping and the size of the treated skin area. Significant amounts of topically applied substances were found adjoining the application area, due to the lateral spreading which takes place on the skin surface. In general, the lateral spreading must be considered to be a competitive process when studying penetration processes of topically applied substances. It has to be considered during drug treatment of small limited skin areas and for the interpretation of recovery rates obtained in penetration studies.

Viscoelastic deformation response of red blood cells under conditions of oscillating centrifugal field

The red cell deformation under the conditions of oscillating centrifugal fields was studied. Experiments were carried out with a modified Cell-Elastometer operating in oscillating mode (0.02 to 0.30 Hz). Gravitational acceleration was sinusoidally modulated between 620 g and 2250 g. At low frequencies (below 0.08 Hz), native red cells followed the applied stress without delay. At 0.09 Hz and up, the cellular deformation was still periodical and included an additional perturbation due to intracellular movements. This perturbation was analysed and quantified. The influence of alterations on the erythrocyte membrane by diamide was analysed to verify the sensitivity of this method. On increasing the membrane stiffness with low concentrations of diamide, the response to oscillatory centrifugal stress was impaired characteristically in terms of amplitude deformation. Based on tangential and centrifugal accelerations, a physical model was developed that describes the basic observable changes on varying the oscillation frequency. From the data it can be concluded that viscoelastic properties of red cells can be analysed and quantified using oscillatory centrifugal accelerations. The described method can become a valid tool to differentiate between membrane alterations or intracellular viscous modifications.

Proliferation and micromilieu during fractionated irradiation of human FaDu squamous cell carcinoma in nude mice

PURPOSE

Previous functional radiobiological experiments demonstrated a significant acceleration of repopulation after 3 weeks and reoxygenation after 12 days of radiotherapy of FaDu tumours. Owing to the temporal coincidence between repopulation and reoxygenation, it was hypothesized that the improved oxygenation status during fractionated irradiation might be the preceding stimulus for increased proliferation. The study investigated whether these changes in repopulation and re-oxygenation are reflected by histological parameters of proliferation and the tumour micromilieu.

MATERIALS AND METHODS

Human FaDu squamous cell carcinomas in nude mice were irradiated with three to 18 fractions of 3 Gy daily or every second day under normal blood flow and clamp hypoxia. At different time points, tumours were excised and stained for Ki67, BrdUrd, epidermal growth factor receptor (EGFR) and markers of the micromilieu (HOECHST 33342, pimonidazole, ER-MP12).

RESULTS

On average, Ki67 and BrdUrd labelling indices decreased initially and increased again at later times during the course of fractionated radiotherapy. A similar kinetic pattern was found for the staining intensity of the EGFR. The vascular density in the viable tumour area remained constant during the whole course of irradiation, while the perfused fraction of vessels decreased within the first week of irradiation and returned to baseline values after 2 weeks. There was a corresponding increase in perfusion and a decrease in cellular hypoxia.

CONCLUSIONS

The histological results were in surprisingly good agreement with the kinetics of clonogen repopulation and re-oxygenation determined previously using functional assays. The results support that the kinetics of repopulation of FaDu squamous cell carcinoma in response to fractionated irradiation are determined not only by intracellular processes, but also by a complex interaction of proliferation parameters with a changing microenvironment.