Predictive values of hCG clearance for risk of methotrexate resistance in low-risk gestational trophoblastic neoplasias

BACKGROUND

Early identification of patients at high risk for chemoresistance among those treated with methotrexate (MTX) for low-risk gestational trophoblastic neoplasia (GTN) is needed. We modeled human chorionic gonadotropin (hCG) decline during MTX therapy using a kinetic population approach to calculate individual hCG clearance (CL(hCG)) and assessed the predictive value of CL(hCG) for MTX resistance.

PATIENTS AND METHODS

A total of 154 patients with low-risk GTN treated with 8-day MTX regimen were retrospectively studied. NONMEM was used to model hCG decrease equations between day 0 and day 40 of chemotherapy. Receiver operating characteristic curve analysis defined the best CL(hCG) threshold. Univariate/multivariate survival analyses determined the predictive value of CL(hCG) and compared it with published predictive factors.

RESULTS

A monoexponential equation best modeled hCG decrease: hCG(t) = 3900 x e(-0.149 x t). Median CL(hCG) was 0.57 l/day (quartiles: 0.37-0.74). Only choriocarcinoma pathology [yes versus no: hazard ratio (HR) = 6.01; 95% confidence interval (CI) 2.2-16.6; P < 0.001] and unfavorable CL(hCG) quartile (< or =0.37 versus >0.37 l/day: HR = 6.75; 95% CI 2.7-16.8; P < 0.001) were significant independent predictive factors of MTX resistance risk.

CONCLUSION

In the second largest cohort of low-risk GTN patients reported to date, choriocarcinoma pathology and CL(hCG) < or =0.37 l/day were major independent predictive factors for MTX resistance risk.

[Rehabilitation strategies of dysfunctional dysphonias in relation to posture]

OBJECTIVE

To improve rehabilitation strategies of functional dysphonias in relation to posture after clinical asssessment and recordings of posture obtained using a stabilometric platform and EquiTest.

MATERIAL AND METHOD

2 groups were compared: group 1 (58 dysphonic patients; 44 women and 14 men), group 2 (19 nondysphonic singers; 11 women and 8 men). They all had a vocal assessment, a test of Freeman and an EquiTest. Their vocal handicap was evaluated by the Voice Handicap Index (VHI) and the WONCA questionnaire. The same assessment was repeated after rehabilitation.

RESULTS

In dysphonic subjects before rehabilitation, the center of gravity during vocal projection and without vocal projection is rather off-set forwards and their postural stability is worse than the group 2 subjects. Vestibular information is less used with a less effective balance strategy. After vocal rehabilitation the voice is improved, vestibular information and the balance strategy are more effective. The VHI Score after rehabilitation goes from 40.36 to 26.35 for a total score of 120.

CONCLUSION

Rehabilitation must be focused on the training of new gestures allowing better postural control thus releasing the phonatory potentials. This is actually possible with several known or modified exercises.

Assessment of a percutaneous iliosacral screw insertion simulator

BACKGROUND

Navigational simulator use for specialized training purposes is rather uncommon in orthopaedic and trauma surgery. However, it reveals providing a valuable tool to train orthopaedic surgeons and help them to plan complex surgical procedures.

PURPOSE

This work's objective was to assess educational efficiency of a path simulator under fluoroscopic guidance applied to sacroiliac joint percutaneous screw fixation.

MATERIALS AND METHODS

We evaluated 23 surgeons' accuracy inserting a guide-wire in a human cadaver experiment, following a pre-established procedure. These medical trainees were defined in three prospective respects: novice or skilled; with or without theoretical knowledge; with or without surgical procedure familiarity. The screw insertion in the human cadaver was performed in two different settings: either without prior training for a first group (G1) or after simulator guidance in the second group (G2). Analysed criteria for each tested surgeon included the number of intraoperative X-rays taken in order to achieve the surgical procedure as well as an iatrogenic index reflecting the surgeon's ability to detect any hazardous trajectory at the time of performing said procedure.

RESULTS

An average number of 13 X-rays was required for wire implantation by the G1 group. G2 group, assisted by the simulator use, required an average of 10 X-rays. A substantial difference was especially observed within the novice sub-group (N), with an average of 12.75 X-rays for the G1 category and an average of 8.5 X-rays for the G2 category. In the second sub-group of operators devoid of procedural knowledge (P-), a significant difference was found, since 12 X-rays appeared on average required in the G1 group versus six in the G2 group. Finally, within the sub-group of operators with technical knowledge (T+), a significant difference also was found since an average of 16 X-rays was required in the G1 versus an average 10.8 X-rays in the G2 group. As far as the iatrogenic index is concerned, we were unable to observe any significant difference between the groups.

DISCUSSION

Despite some methodological variations, we were able to demonstrate the simulator's efficiency in familiarizing the operator with the use of a 2D imaging system as a first step facilitating the procedure conduct in the real 3D patient environment. Novice surgeons (N) having a good lumbosacral joint anatomy knowledge although devoid of specific surgical technique knowledge were the ones who most benefited from this guiding tool. Analysis of the training data collected during simulator's use helps orientating the prospective surgeon toward possession of not yet acquired learning points. This educational program can easily be extended to any other percutaneous technique requiring fluoroscopic control guidance.

LEVEL OF EVIDENCE

Level III prospective diagnostic study.

The mysteries of telomere structure and recognition: could radioprobing help?

PURPOSE

Telomeres are specialized DNA-protein complexes found at the ends of eukaryotic chromosomes. In normal somatic cells these become shorter with each cell division and appear to control their replicative lifespan. However almost all tumours show activation of the enzyme telomerase, a specialised reverse transcriptase/DNA polymerase, that can add new telomeric repeats to the ends of chromosomes and this appears to be a key factor in the cell immortalization process. Consequently there is much current interest in the potential for inhibitors of telomere extension in the treatment of cancer. Several groups have found that it is possible to produce inhibitory molecules that target the telomeric repeat (substrate) DNA rather than the telomerase enzyme itself. This is thought to work because it has been found that in vitro, these DNA sequences can fold up into a four-stranded (quadruplex) structure that the drugs recognise and stabilize, but which is not recognised by the enzyme. However, while medicinal chemists continue to base rational design programs on this hypothesis, there is currently very little evidence that these structures form in vivo, and that in vivo the drugs work by binding to them. To have incontrovertible evidence of where and how these telomerase inhibitors and DNA interact is therefore a pressing concern for a basic understanding of their mechanism of action and effective drug development.

MATERIALS AND METHODS

Radioprobing represents a valuable new approach to the study of DNA structures. Recently we have shown through computer simulations of radioprobing that the technique is a remarkably sensitive probe of quite fine details of DNA conformation. Here we report on our simulations of the binding of a radiolabelled telomerase inhibitor, related to a class of novel inhibitors under development at Nottingham, to a variety of possible structures for telomeric DNA.

RESULTS AND CONCLUSIONS

The predicted cleavage patterns prove to be very sensitive to the DNA structure, and the mode of binding of the drug. These results suggest that radioprobing experiments should be able to provide unambiguous evidence as to the 'true' nature of the telomere-drug complexes, and so aid the rational design programme.

Investigation of PK-PD drug-drug interaction between acenocoumarol and amoxicillin plus clavulanic acid

A pharmacokinetic-pharmacodynamic (PK-PD) drug-drug interaction between acenocoumarol and amoxicillin + clavulanic acid antibiotic was assessed in eight healthy volunteers, using a population PK-PD) model. Each subject received at day 1 a single dose of 8 mg of acenocoumarol. Then 1 g of amoxicillin + 250 mg of clavulanic acid was given from days 3 to 9. On day 8, each subject received a single dose of 8 mg of acenocoumarol concomitantly with the antibiotic combination. Eleven blood samples were taken during 48 h following each acenocoumarol administration. Acenocoumarol plasma concentrations and prothrombin time were measured at each sampling time. We first identified the structural PK model by pooling data from this trial with individual data from other acenocoumarol PK trials. An indirect response model was used to fit PD data. Models were built using a non-linear mixed effect modelling approach with nonmem software. Covariates were tested on PK and PD parameters, including antibiotic treatment. Acenocoumarol PK data were fitted by a two-compartment, first-order input model with log normal inter-individual variability. Weight and antibiotic treatment were found to improve significantly the fit of PK data with a 15% decrease in acenocoumarol clearance with concomitant antibiotics (P < 0.05). An indirect response model was successfully applied to the PK-PD data of acenocoumarol. No covariate, including antibiotic treatment effect, significantly affected PT. Drug-drug interaction was demonstrated at the PK level, without any PD corollary.

Major prognostic value of modeled AUChCG-AFP, a dynamic kinetic marker characterizing tumor marker decline of nonseminomatous germ cell tumors (NSGCT) intermediate-poor-risk patients according to the IGCCCG

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Background: The level of human chorionic gonadotrophin (hCG) and alpha-foetoprotein (AFP) serum tumor marker is well established in NSGCT as prognostic factor, the relevance of marker kinetic analysis under treatment is still unclear. This may be due to the inaccuracy of methods employed so far, simplifying complex exponential decrease curves by a median half-life (HL). We propose to model patient's AFP and hCG decline profiles in order to calculate area under the curve of marker concentrations versus time (AUChCG-AFP) and to test its prognostic value. Methods: Our retrospective study involved 65 pts treated by 4 cycles of bleomycin-etoposide-cisplatin (BEP) regimen for an intermediate-poor-risk group NSGCT in the same center between 1997 and 2008. A kinetic population approach with NONMEM software was used to model equations of hCG and AFP individual decrease profiles between day 7 (D7) and D42 after the first BEP cycle. AUChCG and AUCAFP were calculated between day D0 and D42 as: AUC0–42=AUC0–7+AUC7–42 where AUC0–7 = trapezium area between D0 and D7 while AUC7–42=integral of modeled equation. Survival univariate and multivariate analyses tested the prognostic value of AUChCG-AFP regarding PFS. Results: Mono-exponential models best fitted AFP and hCG decreases: CAFP (t) = 381*e - 0.14 *t +3.27 and ChCG (t) = 1230*e - 0.25 *t +1.22. Three prognostic groups (AUChCG-AFP) were determined according to AUCAFP median and AUChCG terciles: good if AUCAFP<=11729.4 and AUChCG0–42<=6670; intermediate if AUCAFP>11729 and/or if 6670<=AUChCG<18178 and poor risk if AUChCG>18178 whatever AUCAFP. AUChCG-AFP was a significant prognostic factor in the univariate analysis on the 2 year PFS (100% vs 73.8% vs 67.7%, p = 0.035) as well as IGCCCG score (poor/intermediate risk groups), primary site (mediastinal/other) and HLhCG-AFP. Yet AUChCG-AFP was the only significant independent factor in the multivariate Cox model (HR = 3.3, 95%CI = [1.2–9.2], p = 0.032). Conclusions: Modeled AUChCG-AFP is a dynamic kinetic marker characterizing NSGCT patient marker decline during BEP treatment. These results must be validated in a prospective cohort. It may be a major prognostic factor.

No significant financial relationships to disclose.

[Prolongation of anti vitamin K treatment for 18 months versus placebo after 6 months treatment of a first episode of ideopathic pulmonary embolism: a mutlicentre, randomised double blind trail. The PADIS-EP Trial]

BACKGROUND

After stopping a 3 to 6 months course of oral anticoagulation for a first episode of idiopathic venous thromboembolism (VTE), the risk of recurrent VTE is high (10% per year). In this setting, international guidelines recommend at least 6 months treatment. However, this recommendation is not satisfactory for the following reasons: (1) no randomized trial has compared 6 months to extended duration (2 years) anticoagulation; and (2), even though the frequency of recurrent VTE is similar after pulmonary embolism (PE) and deep vein thrombosis (DVT), the fatality rate of recurrent VTE after PE is higher than that after DVT.

METHODS

A French multicentre double blind randomized trial. The main objective is to demonstrate, after a first episode of symptomatic idiopathic PE treated for 6 months using a vitamin K antagonist, that extended anticoagulation for 18 months (INR between 2 and 3) is associated with an increased benefit / risk ratio (recurrent VTE and severe anticoagulant-related bleeding) compared to placebo. The double blind evaluation is ensured using by active warfarin and placebo, and blinded INR. The protocol was approved by the ethics board of the Brest Hospital on the 7th of March 2006. For an alpha risk of 5% and a beta risk of 20%, the estimated sample size is 374 patients.

EXPECTED RESULTS

This study has the potential to: (1) demonstrate that the benefit / risk ratio of extended anticoagulation for 18 months is higher than that observed with placebo in patients with a first episode of idiopathic PE initially treated for 6 months, during and after the treatment period; and (2) to validate or invalidate the contribution of isotope lung scans, lower limb Doppler ultrasound and D-Dimer at 6 months of treatment as predictors of recurrent VTE (medico-economic analysis included).

[Venous thromboembolism and cancer]

Cancer and venous thromboembolism (VTE), VTE and cancer: there is a close bond between these two diseases. On the one hand, a cancer patient runs a high risk of developing VTE. Certain cancer-specific factors, such as its metastatic nature increase this risk. The means involved in the care of cancer (insertion of a venous catheter, chemotherapy, etc.) also increase the probability of a thromboembolism. On the other hand, VTE, especially if it is idiopathic, may be the harbinger of a neoplasm. The present paper involves the dual nature of this relationship, first dealing with several points specific to the occurrence of VTE in a cancer patient, before dealing with the specific care in a curative and prophylactic situation. VTE is then considered as a clinical manifestation prior to a cancer. Several characteristics evoking an underlying neoplasm are known. However, the benefits of the screening for cancer when confronted with an episode of VTE remains to be debated.

Natural textures classification in area V4 of the macaque monkey

Natural texture of an object is an important cue for recognition. In real conditions, the incidence angle of light on natural textures leads to a complex pattern of micro-shading that modifies 3D rendering of surfaces. Little is known about visual processing of material properties. The present work aims to study the coding of natural textures by the neurons of area V4 of the awake macaque monkey. We used patches of natural textures issued from the CURET database and illuminated with two or three different angles with their corresponding controls (scrambled Fourier phase). We recorded the responses of V4 neurons to stimuli flashed in their receptive fields (RFs) while the macaques performed a simple fixation task. We show that a large majority of V4 neurons responded to texture patches with a strong modulation across stimuli. The analysis of those responses indicate that V4 neurons integrate first and second order parameters in the image (mean luminance, SNR, and energy), which may be used to achieve texture clustering in a multidimensional space. This clustering was comparable to that of a pyramid of Gabor filters and was not affected by illumination angles. Altogether, these results suggest that the V4 neuronal population acts as a set of filters able to classify textures independently of illumination angle. We conclude that area V4 contains mechanisms that are sensitive to the aspect of textured surfaces, even in an environment where illumination changes continuously.

[Thrombosis and lung cancer]

This relation is sometimes described as a double association: venous thromboembolism (VTE) can reveal cancer (so-called Trousseau syndrome), but cancer and its treatment are also risk factors for VTE. Lung cancer, frequent and serious, is one of the greatest purveyors of VTE, a disease that pneumologists and oncologists must often confront in diagnosis, prevention, and treatment. This article investigates the epidemiological, prevention, and treatment aspects of VTE in cancer patients, particularly those with lung cancer, but also discusses diagnostic specificities and, briefly, the possible antitumor effect of heparins.

New method for electrostatic force gradient microscopy observations and Kelvin measurements under vacuum

It is shown that both dc and ac electrostatic force gradients can be observed under secondary vacuum by means of phase shifts under amplitude-controlled AFM and a double-pass method. Different flexure mode orders and electrical frequencies have been explored. A theoretical model based on the linear behaviour of the mechanical oscillator allows one to explain the experimental phase shifts and to deduce the key points governing such experiments and the expected performances. As a result, it is shown that surface voltage or Kelvin imaging becomes possible in parallel with morphology with an rms noise in the millivolt range.

Overview of model-building strategies in population PK/PD analyses: 2002-2004 literature survey

AIMS

A descriptive survey of published population pharmacokinetic and/or pharmacodynamic (PK/PD) analyses from 2002 to 2004 was conducted and an evaluation made of how model building was performed and reported.

METHODS

We selected 324 articles in Pubmed using defined keywords. A data abstraction form (DAF) was then built comprising two parts: general characteristics including article identification, context of the analysis, description of clinical studies from which the data arose, and model building, including description of the processes of modelling. The papers were examined by two readers, who extracted the relevant information and transmitted it directly to a MySQL database, from which descriptive statistical analysis was performed.

RESULTS

Most published papers concerned patients with severe pathology and therapeutic classes suffering from narrow therapeutic index and/or high PK/PD variability. Most of the time, modelling was performed for descriptive purposes, with rich rather than sparse data and using NONMEM software. PK and PD models were rarely complex (one or two compartments for PK; E(max) for PD models). Covariate testing was frequently performed and essentially based on the likelihood ratio test. Based on a minimal list of items that should systematically be found in a population PK-PD analysis, it was found that only 39% and 8.5% of the PK and PD analyses, respectively, published from 2002 to 2004 provided sufficient detail to support the model-building methodology.

CONCLUSIONS

This survey allowed an efficient description of recent published population analyses, but also revealed deficiencies in reporting information on model building.

[IFCT-0302 trial: randomised study comparing two follow-up schedules in completely resected non-small cell lung cancer]

BACKGROUND

The authorities advocate a minimalist attitude towards the follow-up of resected bronchial carcinoma (clinical examination and chest x-ray). A survey showed that 70% of French respiratory physicians have chosen to use the CT scanner and often endoscopy. The published data are equivocal and are often based on retrospective studies. Lung cancer is a good model for a study of post-operative surveillance. Recurrences often occur in easily observed areas, they may be detected while still asymptomatic and are sometimes potentially curable. Second primary tumours may develop at the same site.

METHODS

The Intergroupe Francophone de Cancerologie Thoracique (IFCT) has initiated a trial comparing simple follow-up (clinical examination, chest x-ray) with a more intensive follow-up (CT scan, fibreoptic bronchoscopy). The surveillance will take place every 6 months for 2 years and then annually until 5 years.

EXPECTED RESULTS

The main aim is to determine whether intensive follow-up improves patient survival. The opposite question is equally important. If an expensive and demanding follow-up does not affect the chances of cure these results will influence our practice.

Erythropoietin and erythropoietin receptor coexpression is associated with poor survival in stage I non-small cell lung cancer

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Background: The role of erythropoietin (EPO) and its receptor (EPO-R) in tumor biology is under active investigation. This study was designed to evaluate the prognostic impact of EPO and EPO-R expression in stage I non-small cell lung cancer (NSCLC) patients. Methods: EPO and EPO-R expression in 158 tumor samples from resected stage I NSCLC was evaluated using immunohistochemistry and tissue-array technology. Disease specific survival time was calculated from the date of surgery to death from cancer-related causes. Results: EPOR and EPO were highly expressed in 20.9% and 35.4% of the tumors respectively. High EPO-R compared to negative or low level of expression was associated with a poor 5-year disease specific survival (60.6% versus 80.8%, logrank test: p=0.01). High EPO compared to negative and low level of expression was associated with a trend toward a poor 5-year disease specific survival (69.6% versus 80.4%, logrank test: p=0.13). High level of EPO-R and EPO coexpression compared to other groups of patients was associated with a poor 5- year disease specific survival (50.0% versus 80.0% of survival at the end of follow-up, logrank test: p=0.005). In multivariate analysis for disease specific survival, high level of EPO-R and EPO coexpression was an independent prognostic factor for disease specific survival (HR 2.214, 95% CI: 1.012–4.848, p=0.046). Conclusions: These results establish for the first time the pejorative prognostic value of EPO and EPO-R expression in early stage resected NSCLC and suggest a potential paracrine and/or autocrine role of endogenous EPO in NSCLC aggressiveness.

No significant financial relationships to disclose.

Immunohistochemichal expression of biomarkers: a comparative study between diagnostic bronchial biopsies and surgical specimens of non-small-cell lung cancer

BACKGROUND

The increasing use of biomarkers as molecular determinants of responsiveness to conventional chemotherapy or molecular targeted therapy has raised the question of the reliability and reproducibility of their evaluation in bronchial biopsies as compared with corresponding resected surgical specimens.

PATIENTS AND METHODS

Immunohistochemical expression of five markers related to signal transduction [epidermal growth factor receptor (EGFR), phospho-Akt], cell proliferation (Ki-67), DNA repair [excision repair cross-complementing (ERCC)1] and cellular 'immortality' [human telomerase catalytic component (hTERT)], was assessed in 41 patients with operable non-small-cell lung cancer in both bronchial biopsies and whole surgical specimens.

RESULTS

High correlation coefficients were observed between the expression of ERCC1, hTERT and Ki-67 in the biopsies and the surgical specimens [0.83 (P < 0.0001); 0.55 (P < 0.001) and 0.64 (P < 0.0001), respectively]. On the other hand, biomarker expression in biopsy was less correlated with the expression in the whole tissue sample for the markers of signal response and transduction [0.24 (P = 0.17) and 0.29 (P = 0.09) for EGFR and phospho-Akt, respectively].

CONCLUSIONS

Our results indicate a lack of association in the expression of important biomarkers between lung biopsies and corresponding resected tumors, with discordance rates ranging between 9% and 41%. Although these results need to be further validated in larger cohorts, they indicate that the evaluation of the expression of biomarkers in bronchial biopsies can be misleading.

Image processing for resonance frequency mapping in atomic force modulation microscopy

It has been demonstrated that the resonance frequency of the cantilever in atomic force modulation microscopy can be used to study local mechanical properties. We developed a numerical method to achieve mapping of the resonance frequency without significant modification of the device. By making the assumption that the resonance spectrum can be approximated by a Lorentzian curve, we established analytical expressions of the resonance frequency and the width of the curve (damping) depending on the real and imaginary parts of the vibration at a single frequency. Then, resonance frequency and damping images were produced from the recording of both the real and imaginary part images of the complex amplitude. The results on a standard high-impact polystyrene sample are shown.