Position statement on classification of basal cell carcinomas. Part 2: EADO proposal for new operational staging system adapted to basal cell carcinomas.

BACKGROUND: No simple staging system has emerged for basal cell carcinomas (BCCs), since they do not follow the TNM process, and practitioners failed to agree on simple clinical or pathological criteria as a basis for a classification. Operational classification of BCCs is required for decision-making, trials and guidelines. Unsupervised clustering of real cases of difficult-to-treat BCCs (DTT-BCCs; part 1) has demonstrated that experts could blindly agree on a five groups classification of DTT-BCCs based on five patterns of clinical situations. OBJECTIVE: Using this five patterns to generate an operational and comprehensive classification of BCCs. METHOD: Testing practitioner's agreement, when using the five patterns classification to ensure that it is robust enough to be used in the practice. Generating the first version of a staging system of BCCs based on pattern recognition. RESULTS: Sixty-two physicians, including 48 practitioners and the 14 experts who participated in the generation of the five different patterns of DTT-BCCs, agreed on 90% of cases when classifying 199 DTT-BCCs cases using the five patterns classification (part 1) attesting that this classification is understandable and usable in practice. In order to cover the whole field of BCCs, these five groups of DTT-BCCs were added a group representing the huge number of easy-to-treat BCCs, for which sub-classification has little interest, and a group of very rare metastatic cases, resulting in a four-stage and seven-substage staging system of BCCs. CONCLUSION: A practical classification adapted to the specificities of BCCs is proposed. It is the first tumour classification based on pattern recognition of clinical situations, which proves to be consistent and usable. This EADO staging system version 1 will be improved step by step and tested as a decision tool and a prognostic instrument.

Position statement on classification of basal cell carcinomas. Part 1: unsupervised clustering of experts as a way to build an operational classification of advanced basal cell carcinoma based on pattern recognition.

BACKGROUND: No simple classification system has emerged for 'advanced basal cell carcinomas', and more generally for all difficult-to-treat BCCs (DTT-BCCs), due to the heterogeneity of situations, TNM inappropriateness to BCCs, and different approaches of different specialists. OBJECTIVE: To generate an operational classification, using the unconscious ability of experts to simplify the great heterogeneity of the clinical situations into a few relevant groups, which drive their treatment decisions. METHOD: Non-supervised independent and blinded clustering of real clinical cases of DTT-BCCs was used. Fourteen international experts from different specialties independently partitioned 199 patient cases considered 'difficult to treat' into as many clusters they want (≤10), choosing their own criteria for partitioning. Convergences and divergences between the individual partitions were analyzed using the similarity matrix, K-mean approach, and average silhouette method. RESULTS: There was a rather consensual clustering of cases, regardless of the specialty and nationality of the experts. Mathematical analysis showed that consensus between experts was best represented by a partition of DTT-BCCs into five clusters, easily recognized a posteriori as five clear-cut patterns of clinical situations. The concept of 'locally advanced' did not appear consistent between experts. CONCLUSION: Although convergence between experts was not granted, this experiment shows that clinicians dealing with BCCs all tend to work by a similar pattern recognition based on the overall analysis of the situation. This study thus provides the first consensual classification of DTT-BCCs. This experimental approach using mathematical analysis of independent and blinded clustering of cases by experts can probably be applied to many other situations in dermatology and oncology.

Influence of facial skin attributes on the perceived age of Caucasian women.

BACKGROUND AND OBJECTIVE: The facial appearance of a person does not always reflect the chronological age; some people look younger or older than they really are. Many studies have described the changes in skin properties (colour, wrinkles, sagging, micro relief, etc.) with age, but few of them have analysed their influence on the perceived age. The primary objective of this study was to assess the contribution of individual skin attributes of the face on the perceived age of Caucasian women. Secondary objectives were to assess the influence of age and gender of graders with regard to the age perception. SUBJECTS AND METHOD: A random sample of 173 subjects of 20 to 74 years of age was taken from a database of more than 5000 healthy Caucasian women. A trained grader performed visual assessment of facial skin attributes (using a visual analogue scale), and a front face photograph was taken from each subject. Photographs were shown to 48 graders (20 men and 28 women, aged 22-64 years) who were asked to estimate the age of the subjects. Graders were classified as young (less than 35 years), middle age (35-50 years) and seniors (older than 50 years). Partial Least Square regression models were built to predict the chronological and the perceived age from the measured facial individual attributes. The contribution of each attribute within the regression model enabled to measure the relevance of this attribute with regards to age prediction. RESULTS: The eye area and the skin colour uniformity were the main attributes related to perceived age. For age prediction, older graders' estimations were more driven by lips border definition shape and eyes opening, whereas younger graders' (older than 50 years) estimations were more driven by dark circles, nasolabial fold and brown spots. There were statistically significant differences in graders' age perception between gender and among age ranges. Our findings suggest that female graders are more accurate than male, and younger graders (under 35 years) are more accurate than older (over 50 years) to predict Caucasian women age from facial photographs. CONCLUSIONS: Different skin attributes influence the estimation of age. These attributes have a different weight in the evaluation of the perceived age, depending on the age and of the observer. The most important attributes to estimate age are eyes, lips and skin colour uniformity.

[Very low-dose hyper-radiosensitivity: impact for radiotherapy of micrometastases]. / Hyperradiosensibilité aux très faibles doses: impact en radiothérapie des micrométastases.

Radiobiologists have pointed out a novel radiobiological phenomenon observed in many tumor and normal cell lines: hyper-radiosensitivity to very low-dose (HRS) followed by induced radioresistance (IRR) after a threshold dose of 0.1-0.3 Gy that depends on the cell line. Radioresistance at high dose (i.e. higher than 0.5 Gy) and metastatic potential of tumor cells are likely major factors of failure in radiotherapy. A careful review of literature suggests that: 1) radiotherapy does not increase the metastatic potential of tumor cells; 2) radioresistance at high dose and metastatic potential are not related. However, inside a given tumor cell line, highly metastatic clones may elicit more cells showing HRS or are more radiosensitive at high dose than poorly metastatic ones. Recent data obtained from molecular techniques (comet and immunofluorescence assays) applied to single cells irradiated at very low radiation doses (1-100 mGy) suggest that DNA single-strand breaks (SSB) and double-strand breaks (DSB) may be the key-lesions responsible for the HRS phenomenon. These data suggest that the HRS phenomenon may find application in radiotherapy for micrometastasis. These early disseminated and probably unvascularised cells may escape the influence of high-dose chemotherapy after excision of the primary tumor. Considering the link between metastatic potential and HRS, we have previously proposed to apply very low-dose total body irradiation (TBI) at M(0) stage that may prevent the development of micrometastases. Literature data suggest that the smallest radiation dose that can produce HRS without increasing the risk of cancer may be in the milliGrays range.

Exploratory analysis of population pharmacokinetic data from clinical trials with application to isradipine.

Drug level monitoring during routine clinical visits in the course of phase III trials provides a means to document pharmacokinetic variability in a patient population. Such a pharmacokinetic screen was performed for the new calcium antagonist isradipine. A total of 697 blood samples were collected at any time after the morning dose from 252 patients who had received oral doses of isradipine. Three approaches of data analysis based on exploratory (graphical and statistical) techniques were used to relate plasma level to patient demographic data and laboratory parameters. The pharamacokinetics of isradipine seemed to be influenced by the demographic variables of age (already detected in conventional studies) and weight, as well as by the blood serum levels of inorganic phosphorous, uric acid, alkaline phosphatase, and bilirubin, but only to a small, clinically irrelevant extent. The findings from the three approaches were complementary. They suggest that a pharmacokinetic screening in clinical trials is feasible at reasonable experimental cost and effort and provides useful data on interindividual and intraindividual pharmacokinetic variability in patients.

A review of human cell radiosensitivity in vitro.

The survival curves of 694 human cell lines irradiated in exponentially growing phase in vitro were collected from the literature. Among them, 271 were derived from tumors, 423 were nontransformed fibroblasts and other normal cell strains from healthy people or people with some genetic disorders. Seventy-six different cell types are identified, and a specific radiosensitivity could be associated with each, using D and surviving fraction at 2 Gy. Technical factors such as culture medium, feeder cells, and scoring method were found to affect intrinsic radiosensitivity. In particular, the cell type is not a discriminating factor when cells are studied in agar. Results obtained with cells irradiated in agar must be used cautiously, depending on how the cells were prepared for the experiments. The use of feeder cells narrows the range of radiosensitivity of human cells. For cells irradiated as monolayer, it was possible to build a scale of radiosensitivity according to cell type, ranging, in terms of D from 0.6 Gy for the most sensitive cell lines to more than 4 Gy for the most resistant. Considering that, in most cases, we could estimate the variation of radiosensitivity within each cell type, our classification among cell types can be used by researchers to place their results in the context of the literature.

Intrinsic radiosensitivity of human cell lines is correlated with radioresponsiveness of human tumors: analysis of 101 published survival curves.

One hundred and one published survival curves for 92 human cell lines (including 64 tumor lines) have been analyzed in terms of several parameters that are supposed to characterize cell radiosensitivity. Values for n, Do, alpha and beta (from the linear quadratic model), D (Mean Inactivation Dose), and survivals at 2 Gy and 8 Gy have been obtained for each curve. It was found that: I. the initial part of the survival curve is specific to the corresponding cell line; II. this initial part is well characterized by the parameters alpha and D, the values of which can be used to compare intrinsic radiosensitivity among human cell lines; III. human tumor cell line radiosensitivity (expressed in terms of alpha, D and survival at 2 Gy) reflects the clinical radioresponsiveness of the tumors from which the cell lines are derived. Thus, cells from tumors with low radioresponsiveness (melanomas and glioblastomas) are the less radiosensitive. Furthermore, the range of survival at a dose of 2 Gy is broad enough to account, in large measure, for observed differences in clinical tumor radioresponsiveness.

Distribution of radiation sensitivities for human tumor cells of specific histological types: comparison of in vitro to in vivo data.

The radiosensitivities of human tumor cell lines, grouped into 6 histological categories, have been studied using data from the published literature. The parameters alpha, beta, n, D0, D, and the surviving fraction to 2 Gy (S2) and 8 Gy (S8) were calculated. Only the two parameters mainly derived from the initial part of the survival curve, alpha and D, together with S2, provided data which were correlated with the clinical radioresponsiveness of each histological group. Thus, there are intracellular factors which influence clinical radioresponsiveness whose relative importance varies from one histological cell type to another. The value of D gave the most precise characterization of the average group radiosensitivity. It was possible to compare the in vivo radiosensitivities of non-severely hypoxic cells with those of tumor cells irradiated in vitro for 7 tumor lines grown as xenografts in mice. The average radiosensitivity was 1.9 times less in vivo than in vitro. This difference indicates that, in addition to the intrinsic factors of radioresistance demonstrated in vitro, and independently of severe hypoxia, there are other factors which specifically reduce radiosensitivity in vivo.

Correlation between normal tissue complications and in vitro radiosensitivity of skin fibroblasts derived from radiotherapy patients treated for variety of tumors.

PURPOSE: To assess the relationship between fibroblast intrinsic radiosensitivity in vitro and late reactions of normal tissues in patients treated by definitive radiotherapy for variety of tumors. PATIENTS AND METHODS: Ten patients were selected for this study. They were treated by radical radiotherapy for variety of tumors, including non-Hodgkin's lymphoma, prostate, glottic larynx, anal canal, cervix, bladder, thyroid gland, and tonsil pillar. Five patients did not develop any significant late reactions (normally sensitive group, NS). The other five developed late complications in different normal tissues and organs that proved to be fatal in one patient (clinically hyper-sensitive group, HS). Fibroblast cultures were established from punch skin biopsy and radiosensitivity in vitro was measured. The survival fraction at 2 Gy (SF2) was calculated and compared between the two groups. RESULTS: SF2 ranged between 0.10 and 0.38 with a mean of 0.24. The mean SF2 for each of the NS and the HS groups were 0.31 and 0.17, respectively. The non-parametric rank test of Mann-Whitney shows that the difference between the two groups is statistically significant (p = 0.01). CONCLUSION: This study indicates that the in vitro radiosensitivity of skin fibroblasts is correlated with late complications in different organs and normal tissues following radiotherapy for variety of tumors. It also lends support to the existence of a common genetic component determining the radiosensitivity of cells targeted by the late effects of ionizing radiation.

Predictive value of in vitro radiosensitivity parameters in head and neck cancers and cervical carcinomas: preliminary correlations with local control and overall survival.

PURPOSE: To determine whether in vitro radiosensitivity parameters are predictive of treatment outcome. METHODS AND MATERIALS: Biopsies were obtained from patients with head and neck cancers (57) and cervical carcinomas (20) and in vitro radiosensitivity parameters were obtained using the CAM plate assay. RESULTS: In most cases (75%) patients were treated with radiation alone. The median follow up was 461 days. When the whole group of head and neck cancers and cervical carcinomas was considered, patients with a SF2 value below 0.36 had a higher 2-year local control rate (93% versus 68%) and a higher 2-year survival rate (71% vs. 62%) than those with SF2 values above that threshold, but differences were not significant. These trends persisted when head and neck cancers were considered alone with a higher local control rate (86% vs. 67%) and a higher survival rate (75% vs. 52.5%) obtained for patients with a SF2 value below 0.36. When the alpha value was evaluated for the whole group of patients a significantly higher local control rate (80.5% vs. 40.5%) and overall survival rate (71% versus 37.5%) at 2 years were obtained for patients with alpha values above 0.07 Gy-1. When only the group of head and neck cancers was considered, local control rate was significantly higher (79% vs. 33%) but overall survival rate (65.5% vs. 33%) was not significantly higher for alpha values above 0.07 Gy-1. CONCLUSION: These results are encouraging but need to be confirmed with a larger number of patients with a longer follow-up.

Artificial neural network as a tool to compensate for scatter and attenuation in radionuclide imaging.

UNLABELLED: This study investigates the ability of artificial neural networks (ANN) to simultaneously correct for attenuation and Compton scattering in scintigraphic imaging. METHODS: Three sets of experiments are conducted using images of radioactive sources with various shapes and distributions in a homogeneous medium. Numerical Monte Carlo simulations and physical phantom acquisitions of radioactive geometric sources provide the basic material for correction. Our method is based on the following assumptions: information needed to correct for scattering can be extracted from the energy spectrum at each pixel without any assumption concerning the source distribution, and two diametrically opposed energy spectrum acquisitions yield enough information on the source location in the diffusing medium for simultaneous correction for attenuation and scattering. RESULTS: Qualitative and quantitative evaluations of scatter correction by ANN demonstrate its ability to perform scatter correction from the energy spectra observed in each pixel. By using the energy spectra of incident photons detected in two diametrically opposed images, multilayer neural networks are able to perform a proper restitution of projection images without any assumption on geometry or position of radioactive sources in simple geometric cases. ANN corrections compare favorably to those provided by five of the most popular methods. A satisfying correction of both scatter and attenuation is observed for a human pelvis scan obtained during routine clinical practice. CONCLUSION: An ANN is an efficient tool for attenuation and Compton scattering in simple model cases. The results obtained for routine scintigrams in a much more complex situation are strong incentives for performing further studies.

Correlation between the radiosensitivity in vitro of clones and variants derived from a human melanoma cell line and their spontaneous metastatic potential in vivo.

With an experimental model of spontaneous lung metastases of human melanoma in immunosuppressed newborn rats, a large panel of clones and variants with different metastatic potential were derived from a single human melanoma parental cell line (M4Be). Seven clones and variants from M4Be were selected, respectively, for their low (parental, clone 1), intermediate (clones 2 and 3, subvariant 1-) and high (variant 1, subvariant 1+, clone 4) metastatic potential. This paper investigates the relationship between the in vivo metastatic potential of the eight cell lines and their sensitivity to ionizing radiation in vitro (range 0.05-7 Gy). The radiosensitivity was estimated from the mean inactivation dose, a parameter equal to the area under the survival curve plotted in linear coordinates. Examination of the eight survival curves, obtained with cells cultured for no more than five passages after defrost, shows that clone 1, subvariant 1- and the M4be parental line are the most radioresistant cells, clone 4 and subvariant 1+ are the most radiosensitive cells, while clones 2 and 3 and variant 1 showed an intermediate response to radiation. The metastatic potential in vivo of the parental line and the seven sublines is significantly correlated to their radiosensitivity in vitro: the higher the metastatic potential, the higher the radiosensitivity.

A benchmark of cell survival models using survival curves for human cells after completion of repair of potentially lethal damage.

Six models of radiation action (the linear-quadratic model, the multitarget model with initial slope, the repair-misrepair model, the lethal-potentially lethal model, the cybernetic model, the saturable repair model) were tested for their goodness of fit to survival curves for human cells. Fifty-three survival curves for human cells irradiated in plateau phase and after completion of repair of potentially lethal damage (PLD) provided the experimental basis for the tests. Three criteria were considered. The capacity to describe the survival data was estimated, using the error left unexplained by the model. A validation of models was achieved by consideration of the mean residual squared errors. The ability of the parameters to characterize survival curves was investigated, studying their variation within and among curves. The models were not equivalent, whatever the test. The saturable repair model and the multitarget with initial slope model gave the most accurate description of survival data. The linear-quadratic model had the most reliable parameters, so that comparisons of the cell survival curves could be made advantageously. The cybernetic model and the lethal-potentially lethal model were found inappropriate for the analysis of survival curves for human cells after completion of PLD repair.

Correlation between PLD repair capacity and the survival curve of human fibroblasts in exponential growth phase: analysis in terms of several parameters.

Published data on the in vitro radiosensitivity of 46 nontransformed fibroblasts of different genetic origins studied in plateau phase with immediate or delayed plating were used to investigate to what extent potentially lethal damage repair capacity is related to intrinsic radiosensitivity (i.e., irradiated in exponential growth phase). While most of the survival curve analysis is conducted in terms of D0, Dq, and the mean inactivation dose D, some of the data are also discussed in terms of the linear-quadratic model parameter alpha. Using D it is shown that: (i) the radiosensitivity of human fibroblasts in exponential growth phase does not significantly differ from that of plateau-phase fibroblasts with immediate plating; (ii) the radiosensitivity of plateau-phase cells with delayed plating is correlated to the radiosensitivity of cells with immediate plating: the more radioresistant the cell strain in exponential growth phase, the higher its repair capacity; (iii) the repair capacity of the cell strains is related to their genetic origin. In conclusion, we suggest that the survival curve of growing cells depends on the repair capacity of the cells.

A new model describing the curves for repair of both DNA double-strand breaks and chromosome damage.

A review of reports dealing with fittings of the data for repair of DNA double-strand breaks (DSBs) and excess chromosome fragments (ECFs) shows that several models are used to fit the repair curves. Since DSBs and ECFs are correlated, it is worth developing a model describing both phenomena. The curve-fitting models used most extensively, the two repair half-times model for DSBs and the monoexponential plus residual model for ECFs, appear to be too inflexible to describe the repair curves for both DSBs and ECFs. We have therefore developed a new concept based on a variable repair half-time. According to this concept, the repair curve is continuously bending and dependent on time and probably reflects a continuous spectrum of damage repairability. The fits of the curves for DSB repair to the variable repair half-time and the variable repair half-time plus residual models were compared to those obtained with the two half-times plus residual and two half-times models. Similarly, the fits of the curves for ECF repair to the variable repair half-time and variable half-time plus residual models were compared to that obtained with the monoexponential plus residual model. The quality of fit and the dependence of adjustable parameters on the portion of the curve fitted were used as comparison criteria. We found that: (a) It is useful to postulate the existence of a residual term for unrepairable lesions, regardless of the model adopted. (b) With the two cell lines tested (a normal and a hypersensitive one), data for both DSBs and ECFs are best fitted to the variable repair half-time plus residual model, whatever the repair time range.

The relationship between radiosensitivity and repair of potentially lethal damage in human tumor cell lines with implications for radioresponsiveness.

The relationship between intrinsic radiosensitivity and repair capacity was studied for 22 human tumor cell lines in vitro. The experimental material was taken from 19 published papers. Parameters from three radiobiological models were used to assess this relationship: the one-hit multitarget model (D0 and n), the linear-quadratic model (alpha and beta), and the mean inactivation dose (D). Data were obtained for cells in three stages: exponentially growing cells (exp), plateau-phase cells plated immediately after irradiation (ip), and plateau-phase cells plated after completion of PLD repair (dp). No significant difference was found between radiosensitivity of exp and ip cells. There was no correlation between repair capacity and intrinsic radiosensitivity assessed with plateau-phase cells plated immediately after irradiation. The correlation studies between intrinsic radiosensitivity or repair capacity and clinical responsiveness were achieved by assigning cell lines to one of three groups of decreasing in vivo radioresponsiveness: highly, medium, and poorly responsive. There was a significant correlation between radiosensitivity and radioresponsiveness, but no correlation between repair capacity and radioresponsiveness. The average repair capacity was about 0.6 Gy, in terms of D. Three parameters, the mean inactivation dose of exponentially growing cells, of plateau-phase cells plated immediately after irradiation, and of plateau-phase cells plated after completion of PLD repair, could be used equally to assess the relationship between in vitro data and radioresponsiveness. The present results are compared to those obtained in a similar study on a group of 48 nontransformed fibroblast cell strains.

Multiphasic survival curves for cells of human tumor cell lines: induced repair or hypersensitive subpopulation?

Survival of the cells of three human tumor cell lines of differing radiosensitivity was measured after irradiation with single doses of X rays (0.05-5 Gy). At doses below 1 Gy, cells were more radiosensitive than predicted by back-extrapolating the high-dose response. This difference was more marked for cells of the radioresistant cell lines than the radiosensitive cell line so that the "true" initial slopes of the survival curves, at very low doses, were similar for the cells of the three cell lines. This phenomenon could reflect an induced radioresistance so that low doses of X rays are more effective per gray than higher doses, because only at higher doses is there sufficient damage to trigger repair systems or other radioprotective mechanisms which can then act during the time course for repair of DNA injury.

Mean inactivation dose: a useful concept for intercomparison of human cell survival curves.

The mean inactivation dose (D) is calculated for published in vitro survival curves obtained from cell lines of both normal and neoplastic human tissues. Cells belonging to different histological categories (melanomas, carcinomas, etc.) are shown to be characterized by distinct values of D which are related to the clinical radiosensitivity of tumors from these categories. Compared to other ways of representing in vitro radiosensitivity, e.g., by the multitarget parameters D0 and n, the parameter D has several specific advantages: (i) D is representative for the whole cell population rather than for a fraction of it; (ii) it minimizes the fluctuations of the survival curves of a given cell line investigated by different authors; (iii) there is low variability of D within each histological category; (iv) significant differences in radiosensitivity between the categories emerge when using D. D appears to be a useful concept for specifying intrinsic radiosensitivity of human cell lines.

Initial slope of radiation survival curves is characteristic of the origin of primary and established cultures of human tumor cells and fibroblasts.

The published survival curves of 110 human tumor cell lines and 147 nontransformed human fibroblast strains have been reanalyzed using three different statistical methods: the single hit multitarget model, the linear-quadratic model, and the mean inactivation dose. The 110 tumor cell lines were classified in two ways: (a) into three categories defined by clinical radiocurability criteria, and (b) into seven categories based on histopathology. The 147 fibroblast strains were divided into eight genetic groups. Differences in the radiosensitivities of both the tumor cell and fibroblast groups could be demonstrated only by parameters that describe the slopes of the initial part of the survival curves. The capacity of the survival level to identify significant differences between groups was dose dependent over the range 1 to 6 Gy. This relationship showed a bell-shaped curve with a maximum at 1.5 Gy for the tumor cell lines and 3 Gy for the fibroblasts. Values for intrinsic radiosensitivity for a number of groups of tumors have also been obtained by primary culture of tumor cells. These values are strictly comparable to those obtained by clonogenic methods. This confirms that intrinsic radiosensitivity is a determinant of the response of tumor cells to radiotherapy and suggests that tissue culture methods may be used as a predictive assay.

Membrane modifications of red blood cells in Alzheimer's disease.

Red blood cells (RBC) from 24 Alzheimer's disease (AD) patients, 18 age- and sex-matched nondemented (ND) patients, hospitalized in the same facility for orthopedic problems, and 18 healthy volunteers aged 30-52 years were studied in order to gain insight into the nature of RBC membrane modifications in AD. Significant differences were found between RBC from AD and ND patients or young controls respectively for annexin V-binding (45.5 +/- 18.0% vs 27.1 +/- 14.7 and 2.7 +/- 1.9, p = .003), fraction of glycerol resistant cells (30.8 +/- 11.1% vs 19.6 +/- 6.4 and 10.2 +/- 3.1, p = .026), cell electrophoretic mobility in polymer (1.028 +/- 0.022 microns sec-1 V-1 cm vs 1.046 +/- 0.022 and 1.053 +/- 0.021, p = .02) and only limited significance for the filterability (1.46 +/- 0.12 msec vs 1.58 +/- 0.11 and 1.54 +/- 0.11, p = 0.1). A logistic analysis, using simultaneously several features as independent variables, suggested the combined use of annexinV- binding, glycerol resistance, and cell filterability which allowed the assignment of 95% of patients from this cohort to the right group. A prospective analysis of a larger cohort is required for the estimation of the diagnostic value of this test battery. In addition, the high level of annexin binding is characteristic of a disruption of the phospholipid asymmetry in aged or damaged cells, while the high glycerol resistance combined with low electrophoretic mobility an rigidity characterize young RBC, thus indicating an enhanced turnover of RBC in Alzheimer's disease.