Validation of methods for the detection and quantification of engineered nanoparticles in food

The potential impact of nanomaterials on the environment and on human health has already triggered legislation requiring labelling of products containing nanoparticles. However, so far, no validated analytical methods for the implementation of this legislation exist. This paper outlines a generic approach for the validation of methods for detection and quantification of nanoparticles in food samples. It proposes validation of identity, selectivity, precision, working range, limit of detection and robustness, bearing in mind that each "result" must include information about the chemical identity, particle size and mass or particle number concentration. This has an impact on testing for selectivity and trueness, which also must take these aspects into consideration. Selectivity must not only be tested against matrix constituents and other nanoparticles, but it shall also be tested whether the methods apply equally well to particles of different suppliers. In trueness testing, information whether the particle size distribution has changed during analysis is required. Results are largely expected to follow normal distributions due to the expected high number of particles. An approach of estimating measurement uncertainties from the validation data is given.

Validation of an optical surface plasmon resonance biosensor assay for screening (fluoro)quinolones in egg, fish and poultry

A surface plasmon resonance biosensor immunoassay has been developed for multi-residue determination of 13 (fluoro)quinolone antibiotics in poultry meat, eggs and fish. The following performance characteristics were determined according to the guidelines laid down for screening assay validation in European Decision 2002/657/EC: detection capability, specificity/selectivity, decision limit, repeatability, ruggedness and stability. The detection capability estimated for norfloxacin, the reference fluoroquinolone, was below 0.5, 1 and 1.5 ng g⁻¹ for poultry meat, egg and fish, respectively. The screening assay proved specific and showed satisfactory sensitivity below the MRL levels even though flumequine and oxolinic acid had lower cross-reactivities. A wide range of non-MRL substances were also detected at concentrations below 10 ng g⁻¹. Repeatability was good with both intra- and inter-assay coefficients of variation 56%; ruggedness was also demonstrated.

Abstract P6-01-08: Keratin 5/14+ Progenitor Cell Concept of Breast Epithelium: Revisited

Background: The role of keratin (K) 5/14+ progenitor cells as precursor cells of the breast epithelium has been demonstrated both in culture and in situ. This cell model opens a new field in which distinct cell subtypes can be evaluated in terms of their functional state and describes how these cells may give rise to either benign or malignant tumors. Material and Methods: In this study, we used modern triple immunofluorescent labeling experiments to visualize directly different cell types and their functional status applying, as a reference, antibodies to basal (K5/14) and glandular (K8/18) keratins and a myoepithelial marker in combination with antibodies to ER-alpha, Ki67, BCL2 and c-kit in normal resting breast epithelium and in 30 cases of ductal neoplasia of low grade pathway and 8 cases of epithelial hyperplasia. Different cell types were quantitatively assayed. Immunolabeling results were supported with quantitative real time PCR.

Results: Basal and glandular keratins in the normal luminal breast epithelium were found to be expressed in highly specific sequential pattern from K5/14+progenitor cells to K8/18+ glandular cells. ER alpha, Ki67, c-kit and BCL2 were found differentially expressed in various subtypes of the breast epithelium, ER-alpha was expressed only in a subset of glandular cells thus subdividing the glandular lineage into ER-alphapositive and negative subcategories. The highest Ki67-proliferation was found in phenotypically glandular cells which are ER-alpha negative. BCL2 was characteristically co-expressed in glandular cells, whereas c-kit was detected mainly in earlier glandular cells. Benign epithelial hyperplasia showed a striking similarity to normal luminal breast epithelium. In terms of functional differentiation these cells disclosed the same ER-alpha, BCL2 and c-kit expression as that observed in normal epithelium. In contrast to UDH, all types of low-grade in-situ neoplasia of ductal type are characterized by expression of only glandular keratins 8/18. The tumour cells co-expressed ER-alpha, BCL2 and Ki67. On the other hand, c-Kit was not expressed in these lesions.

Discussion: From our data, it is evident that basal (K5/14) and glandular keratins (K8/18) are expressed in highly specific hierarchical patterns related to stage of glandular differentiation. This phenotypic hierarchy of cells is furthermore bound to a differential expression of ER, Ki67, c-kit and BCL2 in a very specific manner. Usual ductal hyperplasia disclosed a striking similarity to the resting glandular epithelium. In contrast, all types of low grade intraepithelial neoplasia not only retain the keratin patterns of their (normal) glandular counterpart but show the same functional differentiation with a positive expression of ER and BcL2 and lack of c-kit. This similarity indicates that these lesions may derive from more differentiated glandular cells of the lobular breast epithelium. The data presented here confirm that the K5/14+ progenitor cell concept provides important insight into the functional nature of normal breast epithelium and in proliferative diseases.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-01-08.

First epidemiological analysis of breast cancer incidence and tumor characteristics after implementation of population-based digital mammography screening

PURPOSE

To epidemiologically evaluate the impact of digital mammography screening on incidence rates and tumor characteristics for breast cancer.

MATERIALS AND METHODS

The first German digital screening units in the clinical routine were evaluated during the implementation period by using data from the cancer registry to compare the incidence rate of breast cancers and prognostic characteristics. 74 % of women aged 50 - 69 within the region of Muenster/Coesfeld/Warendorf were invited between 10 / 2005 and 12 / 2007 for initial screening; 55 % participated (n = 35 961).

RESULTS

In 2002 - 2004 the average breast cancer incidence rate (per 100,000) was 297.9. During the implementation of screening, the rate rose to 532.9 in 2007. Of the 349 cancers detected with screening, 76 % (265 / 349) were invasive compared to 90 % (546 / 608) of cases not detected with screening during the same period. 37 % (97 / 265) of cancers detected in the screening program had a diameter of <or= 10 mm and 75 % (198 / 265) were node-negative compared to 15 % (79 / 546) and 64 % (322 / 503), respectively, in cancers detected outside the screening program. The distribution of invasive tumor size (pT categories) and the nodal status differed with statistical significance between cancers detected in and outside the program (p = 0.005 and p = 0.004, respectively).

CONCLUSION

Epidemiological data shows that the implementation of a population-based screening program led to a relevant increase in the age-specific breast cancer incidence rate. The characteristics of breast cancers detected in the screening program comply with the requirements of the European guidelines and are significantly favorable compared to tumors diagnosed outside the program. These findings indicate that digital mammography screening fulfills the requirements for an early tumor detection tool.

[Diagnostics of microcalcifications from minimally invasive biopsies in mammography screening: results from the prevalence phase]

BACKGROUND

In mammography screening programmes carried out according to European guidelines, minimally invasive biopsies (MIB) are performed on up to 3% of participants. The aim of this study was to analyse the spectrum of histopathological findings including B categories in MIBs with microcalcifications compared to MIBs without microcalcifications.

MATERIAL AND METHODS

Prospectively collected histological findings of MIBs taken during the period July 2006 to June 2007 were analysed using the Breast Screening Pathology Database of the Reference Centre in Münster.

RESULTS

Of the 4,326 MIBs investigated, 2,161 were benign (B1-B3) whereas 2,165 were malignant (B4-B5) resulting in an overall malignancy rate of 50.04%. Of the MIBs 1,809 contained microcalcifications and 2,517 did not. Cases with microcalcifications showed a different distribution of B categories: B2 was found in 44.5% versus 24.2%, B3 in 18.2% versus 5.5% and the malignancy rate of cases with microcalcifications was 36.8% versus 59.5%. Of all cases of ductal carcinoma in situ (DCIS) detected in the screening programme, 83.35% were diagnosed in MIBs containing microcalcifications.

CONCLUSIONS

MIBs containing microcalcifications showed a different spectrum of diagnoses, especially higher rates of B3 lesions. Even though MIBs without microcalcifications showed a higher overall malignancy rate, most cases of DCIS were diagnosed in MIB containing microcalcifications.

[Immunohistochemistry in breast pathology: differential diagnosis of epithelial breast lesions]

Proliferative epithelial breast lesions include a wide variety of benign hyperplastic and noninvasive neoplastic lesions, as well as invasive carcinomas. Mammographically these lesions may show microcalcifications, architectural distortions or mass lesions. The task of the pathologist begins with a preoperative diagnosis by means of minimally invasive biopsy. His diagnosis forms the basis for not only the radiological-pathological correlation diagnosis, but also for the management of benign proliferative breast disease lesions, as well as therapeutic decisions in the case of malignant lesions.In daily practice, immunohistochemistry is the method of choice for clarifying difficult cases. The aim of this chapter is to describe the relevant markers in breast pathology and to provide an algorithmic approach to different proliferative breast disease lesions.

Development of an optical surface plasmon resonance biosensor assay for (fluoro)quinolones in egg, fish, and poultry meat

The aim of this study was to develop an optical biosensor inhibition immunoassay, based on the surface plasmon resonance (SPR) principle, for use as a screening test for 13 (fluoro)quinolones, including flumequine, used as veterinary drugs in food-producing animals. For this, we immobilised various quinolone derivatives on the sensor chip and tested binding of a range of different antibodies (polyclonal and one engineered antibody) in the presence and absence of free (fluoro)quinolones. The main challenge was to detect flumequine in an assay giving good results for the other compounds. One antigen-antibody combination proved satisfactory: polyclonal antibodies raised against a dual immunogen and, on the sensor chip, a fluoroquinolone derivative. It was the first time that this concept of the bi-active antibody was described in the literature. The assay, optimised for detection in three matrices (poultry muscle, fish, and egg), was tested on incurred samples prepared by liquid extraction followed by two washing steps. This rapid, simple method proved adequate for detecting at least 13 (fluoro)quinolones at concentrations below established maximum residue levels (MRLs). The reference molecule norfloxacin could be detected in the range of 0.1-10 microg kg(-1) in extracts of egg and poultry meat and in the range of 0.1-100 microg kg(-1) in extracts of fish. The determined midpoints of these calibration curves were about 1, 1.5 and 3 microg kg(-1) in poultry meat, egg and fish, respectively.

Digital mammography screening: average glandular dose and first performance parameters

PURPOSE

The Radiation Protection Commission demanded structured implementation of digital mammography screening in Germany. The main requirements were the installation of digital reference centers and separate evaluation of the fully digitized screening units. Digital mammography screening must meet the quality standards of the European guidelines and must be compared to analog screening results. We analyzed early surrogate indicators of effective screening and dosage levels for the first German digital screening unit in a routine setting after the first half of the initial screening round.

MATERIALS AND METHODS

We used three digital mammography screening units (one full-field digital scanner [DR] and two computed radiography systems [CR]). Each system has been proven to fulfill the requirements of the National and European guidelines. The radiation exposure levels, the medical workflow and the histological results were documented in a central electronic screening record.

RESULTS

In the first year 11,413 women were screened (participation rate 57.5 %). The parenchymal dosages for the three mammographic X-ray systems, averaged for the different breast sizes, were 0.7 (DR), 1.3 (CR), 1.5 (CR) mGy. 7 % of the screened women needed to undergo further examinations. The total number of screen-detected cancers was 129 (detection rate 1.1 %). 21 % of the carcinomas were classified as ductal carcinomas in situ, 40 % of the invasive carcinomas had a histological size <or= 10 mm and 61 % < 15 mm. The frequency distribution of pT-categories of screen-detected cancer was as follows: pTis 20.9 %, pT1 61.2 %, pT2 14.7 %, pT3 2.3 %, pT4 0.8 %. 73 % of the invasive carcinomas were node-negative.

CONCLUSION

The average glandular dose for all three digital screening units was below the AGD of the analog mammography screening units (1.7 mGy) used in the German trial projects. Nevertheless, the performance indicators of the European guidelines were fulfilled with respect to the prevalent tumor detection rate and tumor size distribution while meeting an acceptable recall rate. This first evaluation of a digital screening unit in Germany demonstrates that the quality standards are met at lower radiation dosage levels than in screen-film mammography.

Maintenance immunotherapy by repetitive low-dose donor lymphocytes infusions in a child with relapse state aml after allogeneic stem cell transplantation

The treatment of a child with a relapsed state acute leukemia after allogeneic stem cell transplantation (allo-SCT) is a challenge. The authors report about a child with an acute myelogenous leukemia (AML), which relapsed after allo-SCT despite immunological intervention. It was further treated with a second line chemotherapy followed by an infusion of stem cells and donor lymphocytes. Because of an immense risk for a further relapse, an immunological maintenance therapy was also performed, consisting of repetitive infusions of low doses of donor lymphocytes combined with low-dose chemotherapy. Presently, the child is in continuous complete remission and has a good quality of life.

Androgen-binding protein is co-expressed with oxytocin in the male reproductive tract

Androgen-binding protein (ABP) and the posterior lobe hormone oxytocin (OT) were co-localized in male rat reproductive organs. Immunostaining of serial semi-thin sections revealed a high rate of coexistence of both antigens in Sertoli cells and in the epithelial cells of the prostate. There was a considerably less co-localization of OT and ABP in epithelial cells of the epididymis, and in the different tissues of the ductus deferens. In situ hybridization with synthetic oligonucleotides complementary to a fragment of ABP mRNA showed specific staining in the same sites that were immunostained for ABP. ABP was isolated by affinity chromatography from homogenates of testis, epididymis, prostate and the content of the prostate lumen. Identical protein patterns could be shown with surface-enhanced laser desorption/ionization time-of-flight mass spectrometry in all samples except for the epididymis indicating that ABP structure is similar in all these tissues. ABP seems to be expressed in specified cells throughout the male rat reproductive tract. Most of these cells appear to be oxytocinergic. ABP and OT have previously been detected in the ejaculate. The observed epithelial cells are likely to be their source.