Peter Hufnagl

Improvement of breast cancer prognostication using cell kinetic-based silver-stainable nucleolar organizer region quantification of the MIB-1 positive tumor cell compartment

Abstract. Recently, it was stated that the proliferative activity (P) of a cell population could be indirectly calculated by multiplying the MIB-1 immunopositivity and silver-stainable nucleolar organizer region (AgNOR) features extracted exclusively in MIB-1 positive (pos.) nuclei: P=MIB-1×AgNORMIB-1pos.. To study the prognostic significance of this hypothesis, MIB-1 immunohistochemistry and AgNOR staining were applied on a series of 89 cases of breast cancer with an 8-year follow-up period. The mean MIB-1 immunopositivity (MIB-1mean) was evaluated immunohistometrically on paraffin sections using a TV image analysis system CM-2 (Hund, Wetzlar, Germany). Later, a combined MIB-1/AgNOR staining was applied and evaluated using a TV image analysis system AMBA (IBSB, Berlin, Germany). The AgNOR features of 150 randomly chosen tumor nuclei were investigated, irrespective of their MIB-1 status (AgNOR count, AgNOR area). Later, a second measurement was performed on 100 MIB-1 positive tumor nuclei exclusively (AgNOR countMIB-1pos., AgNOR areaMIB-1pos.). AgNOR count and AgNOR countMIB-1pos. showed a different data distribution [2.7±0.7 (mean±SD) vs 3.9±1.1; r=0.315, P=0.014]. Similar results were obtained for AgNOR area and AgNOR areaMIB-1pos. (5.1±2.1xa0µm2 vs 7.5±2.4xa0µm2; r=0.501, P<0.001). Kaplan–Meier survival curves revealed significant differences for MIB-1mean (P=0.0018) and AgNOR areaMIB-1pos. (P=0.0340). In Cox models, both parameters provided independent prognostic information. Using their combination, the P, three groups of patients with statistically different survival could be separated (P=0.0014). Thus, the combination of MIB-1-immunopositivity and AgNOR measurements in MIB-1 positive nuclei appears to be more useful in breast cancer prognosis than the exclusive application of one of the two methods. By this combined application, probably effects of tumor biology are represented more precisely.

The virtual microscope for routine pathology based on a PACS system for 6 Gb images

Abstract The use of digital images for diagnosis, known as radiology, can bring substantial improvements for efficiency and functionality in routine histology. We developed a system that allows diagnosis with a virtual microscope using digital images from complete slides under highest magnification. The major technical challenges were the large data volumes and the necessary visualisation speed. Using image streaming technologies, we developed a system that solves those problems. We present our system and its advantages. Fast access to reference cases, easy integration of telepathology and an uninterrupted digital workflow may, in the long-term, convince pathologists of the digital virtual microscope (DVM) as a realistic alternative to light microscope.

Fetal autopsy: a review of recent developments

OBJECTIVEnTo analyze recent changes in fetal autopsy in response to developments in prenatal medicine.nnnMETHODnDuring the period 1988 through 1997, 783 fetuses (75% induced abortions, 18% spontaneous abortions, and 7% stillbirths, all between the 12th and 40th week of gestation) with prenatally diagnosed congenital malformations and chromosomal aberrations were analyzed. We divided the autopsies into two periods: period A (1988-92, n=370) and period B (1993-97, n=413). All fetuses were analyzed before completion of 20 weeks of gestation. The malformations of the organ systems were presented according to their frequency for fetuses independent of the weeks of gestation.nnnRESULTSnAn autopsy was performed prior to the completion of 20 weeks of gestation for 24% of the fetuses in period A and 45% in period B (P<0.0001). The number of diagnosed congenital heart malformations increased from 16% in period A to 23% in period B. The number of congenital heart malformations before completion of 20 weeks of gestation was only 21% in period A as compared to 42% in period B.nnnCONCLUSIONSnIn period B, clinical questions were raised in a more concrete form and ultrasound images gave more detailed information than in period A. Access to prenatal findings prior to postmortem examination has helped investigators to develop a specific, clinically oriented, autopsy strategy based on the prenatal findings which makes it possible to diagnose very small malformations and to select sectional planes of special interest. The use of an interdisciplinary database is required for communication.

Computer-assisted image analysis of nucleolar organizer regions (NORs): a pilot study of astrocytomas and glioblastomas.

Computer-assisted image analysis was used to measure nucleolar organizer regions (NORs) of 22 astrocytomas and glioblastomas. Image analysis provides reproducible information about number and size of NORs together with further karyometric data, which can be compared and processed with other patient-related data. Our study exhibits a statistical relationship between number and size of NORs and malignancy of the measured gliomas.

AMBA/D: a new programming environment for image processing

Recent practice in image processing is dominated by heuristic methods used to design practical, relevant algorithms. To ensure high efficiency in the design process, the communication between user and computer should be as direct as possible. An interactive software system for image processing is required to fulfill this demand. Interpreter-based systems with high interactivity available on the software market have the drawback of low operation speed. In AMBA/D we combine the performance of a compiler/based system, with the interactivity of an interpreter system. The AMBA/D system is an interactive programming environment with integrated facilities to create, compile, execute, and debug programs. In AMBA/D, a compiler language, direct execution, and programming concept is combined with a collection of high-level image processing procedures. The design of a special compiler language was necessary because existing computer languages like FORTRAN, C, etc., do not fulfill our requirement of interactivity. The system runs of an IBM-compatible personal computer and can be used with different types of commercially available frame grabbers.

Image analysis software and sample preparation demands

Image analysis offers the opportunity to analyse many processes in medicine, biology and engeneering in a quantitative manner. Experience shows that it is only by awareness of preparation methods and attention to software design that full benefit can be reaped from a picture processing system in the fields of cytology and histology. Some examples of special stains for automated analysis are given here and the effectiveness of commercially available software packages is investigated. The application of picture processing and development of related special hardware and software has been increasing within the last years. As PC-based picture processing systems can be purchased at reasonable costs more and more users are confronted with these problems. Experience shows that the quality of commercially available software packages differ and the requirements on the sample preparation needed for successful problem solutions are often underestimated. But as always, sample preparation is still the key to success in automated image analysis for cells and tissues. Hence, a problem solution requires the permanent interaction between sample preparation methods and algorithm development.

PARTICLE: an expert system for the analysis of microscopic object populations

Expert systems are exciting for primarily two reasons: first they are generally useful, practical programs that fulfil an actual need; and second they are available. These are the reasons that they constitute most of AIs practical and commercial success /19/. At their best, expert systems may be as helpful as having an expert consultant right there /2/. Expert systems are computer software that can function as a consultant, providing guidance advice and assistance in decision making, handling automation of humans ability in sharply defined and delineated regions. In this sense it is possible to replace a human expert by an expert system /3/. Because human expertise is rare and expansive expert systems are needed /18/.

Models for histometry of tumors

Caryoxnetry and histoinetry are the two characterization levels for histological patterns. A wide spectrum of caryoinetrical methods exists (characterization of size and form, densitometry, nuclear texture analysis) and there is often a good correlation between measured parameters and diagnosis as well as proosis, especially in tumor diagnostic /14/15/20/. The development of histoinetry has just begun.