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H Christen

Publications and source records attributed to H Christen.

At least 19 recordsLinked to original sources
PubMed1992

Age-related modification of average volume and anisotropy of vascular smooth muscle cells.

The aim of this study was to determine what changes in the arterial wall are related to age. In two groups of rabbits, one young and one adult, the aorta and carotid were studied using a morphometric approach based on stereological axioms and planimetric morphometry. The problem of anisotropy of smooth muscle cells is discussed in detail. Two forms of anisotropy must be distinguished, that of single cell and that due to the histological pattern of the smooth muscle cells in the arterial wall. Our results show in adult animals, as compared to the young ones, statistically significant decrease in anisotropy of the cell pattern which tends to become more regular. Moreover, in aorta and carotid of young and adult animals there is an increment of 95.39% and 80% of the absolute cell volume, respectively. We suggest that there may be a direct relationship between aging and phenotypical modulation of the smooth muscle cells and that the modification of the architectural cell pattern with age may represent an adaptive event related to the change in forces acting upon the arterial wall.

Aging↗
PubMed1992

Morphological, immunohistochemical, stereological and nuclear shape characteristics of proliferative Leydig cell alterations in rats.

Proliferative Leydig cell (LC) alterations (hyperplasia, adenoma) of laboratory rats often pose diagnostic problems because the progression from normal to hyperplasia to neoplasia is continuous. The LC compartments of 130 Wistar rats (kfm: WIST strain) of approximately 2 years of age were examined. Ten typical cases conventionally classified as being normal or as showing diffuse or focal hyperplasia or small or large adenomata were investigated in more detail. In large adenomata, areas with large and small LC nuclei were identified. Immunohistochemical characterization, EM examination, as well as stereologic and planimetric investigations were performed. Hyperplastic and neoplastic LC essentially retained their normal appearance and immunohistochemical characteristics, but were found to contain more lipid droplets, fibroblast-like cells and patches of collagen than normal LC at the EM level. LC proliferation was accompanied by significant LC hypertrophy. LC nuclei of hyperplastic LC compartments were slightly larger while those of LC adenoma were markedly larger than nuclei of normal LC. The values for circle-related and ellipticity factors indicated that the nuclei of normal and hyperplastic LC were more markedly oval than nuclei of neoplastic LC. Concavity factor and bending energy measurements revealed that the small and oval nuclei of normal and hyperplastic LC had significantly more and deeper indentations than the larger and somewhat rounder nuclei of neoplastic LC. It is concluded that LC proliferations conventionally diagnosed as hyperplasia or adenoma on the basis of their size were composed of cytologically different LC populations.

Adenoma↗
PubMed1991

[Morphology and function of macrophages in AIDS in broncho-alveolar lavages (BAL)].

HIV infects susceptible T-cell and mononuclear phagocyte targets. Unlike the dramatic changes that occur with T-cells during HIV disease, changes in monocyte and macrophage phenotype and function are qualitatively minimal. The aim of the study was to quantitatively analyze the morphology of macrophages in broncho-alveolar lavages in patients without AIDS, with AIDS, with AIDS complicated by Pneumocystis carinii and in carcinoma patients. In patients with AIDS, the nuclei of macrophages demonstrate a higher integrated optical density (2P less than 0.10), are bigger in size (2P less than 0.05) and have less notches (2P less than 0.02).

Acquired Immunodeficiency Syndrome↗
PubMed1991

[What role does informatics play in pathology?].

Informatics can be understood as an element of management, dealing with structures of files, algorithms and hardware. The most important prerequisite to successful use of informatics is an optimal compatibility between these single elements. To realize this compatibility and to ascertain a permanent operability of informatics in pathology, the realization of the following two conditions are advisable: 1) The differentiation between a general administrative system of the whole department of pathology and systems of special units (e.g. laboratories); 2) the modularity of the laboratory systems.

Humans↗
PubMed1991

Some fundamental aspects of morphometry in clinical pathology, demonstrated on a simple, multipurpose analysis system.

The aim of this study was (1) to investigate the value of morphometry, (2) to fix a set of parameters suitable for analyzing diagnostic problems, and (3) to create a general strategy for data storage and for user-friendly data management. The intrinsic value of morphometry lies in the fact that in contrast to other morphologic methods, it permits the presentation of findings in the form of numbers. The following set of morphometric parameters, in the broad sense of the term morphometry, is standard in our laboratory: planimetric parameters (shape descriptors), parameters of the gray value histogram (descriptors of the general gray value distribution), texture parameters (descriptors of the correlation between various image segments), invariant moments (descriptors of the size and localization of textural image segments) and densitometric parameters. The introduction of morphometric procedures into the daily routine is facilitated if data registration and evaluation are performed separately. Original data generated by direct measurement are primary or raw data, which are stored as such. In a separate, second step these raw data are used to compare more or less complex morphometric parameters, which are called "secondary data". A system designed for separate data registration and evaluation can easily be adapted to new methodologic developments. For instance, primary data on objects (gray values, coordinates of the contour) measured one time in the past can be reused at any other time for computing new features from these data. This procedure is comparable to the possibilities in immunohistochemical staining: new immunohistochemical stains can be applied to newly prepared sections of old tissue blocks.

Computer Communication Networks↗
PubMed1991

The significance of morphometric methods in cytologic diagnostics: differentiation between mesothelial cells, mesothelioma cells and metastatic adenocarcinoma cells in pleural effusions with special emphasis on chromatin texture.

Opinions differ widely as to the value of morphometric techniques for differentiating between mesothelial cells, mesothelioma cells and metastatic adenocarcinoma cells in pleural effusions. The significance of the changes in the chromatin structure to differentiate between these three cell types was stressed by various scientific groups only qualitatively, and until now no group has used digital methods to quantify chromatin structures. The controversy about the value of morphometric methods was the reason for conducting the following study. We wanted to investigate (i) the importance of various planimetric and texture parameters as well as invariant moments as morphometric discriminators; and (ii) to set up a data structure to make possible the further diagnostic use of the multivariate morphometric analyses method for other applications. The present findings show that nuclear size and form are not the decisive factors in differentiating between reactive cells and mesothelioma cells, but pixel related texture parameters and invariant moments are. All parameter types used showed differences between reactive cells and cells of adenocarcinoma metastases. Invariant moments and shape descriptors, but not texture parameters are used to discriminate between mesothelioma cells and cells of adenocarcinoma metastases.

Adenocarcinoma↗
PubMed1990

[Prerequisites for the application of statical morphometry in diagnostics].

The aims of the present paper were: 1. to test a set of parameters suitable for quantifying morphological features; 2. to create a generally valuable strategy for data storage and for a user friendly data management; 3. to examine the parameter set and the conception for an optimal data management by the quantification of cytological specimens of pleural effusions. The significance of a distinction between "primary parameters" (data directly captured during the measurement) and "secondary data" (data calculated from the primary data) is explained. In the first step of classification of the cytological specimens 81.8% of the patients with reactive alterations of mesothelial cells (n = 11) and 100% of the patients with tumours (mesotheliomas and metastasis of adenocarcinomas) (n = 19) were correctly classified with the aid of a little "expert system". In the second step (discrimination between mesotheliomas (n = 6) and metastasis of adenocarcinomas (n = 13] all patients were correctly classified.

Cytodiagnosis↗
PubMed1989

A simple "expert system" for morphometric evaluation of cells in pleural effusions.

Quantitation in diagnostic pathology serves to improve both diagnostic reliability and the prognosis of various malignant tumors. Unfortunately, flexible, user-friendly, reasonably priced and compatible morphometric systems are hardly available on the market. A modular Apple II PC-based system was therefore developed in-house. It records stereologic, planimetric and digital image analysis data and calculates secondary parameters. Detailed statistical analyses can be performed, after data transfer, on larger computers. A typical application of diagnostic morphometry is to determine whether, and with which probability a patient with an unclear histopathologic finding can be assigned to one or more groups of patients with known diseases and prognoses. To this end morphometric data of the patient under investigation are compared with other patient data stored in an expert system. This paper describes the concept of an expert system carried out on the Apple II PC system mentioned above and outlines the evaluation procedures. Invariant moments were used to describe nucleus textures. Results obtained from the cytological analysis of pleural effusions demonstrate that with this approach it is possible to differentiate between normal mesothelium, mesothelioma and metastases of adenocarcinomas.

Adenocarcinoma↗
PubMed1989

Digital image analysis in cytological diagnosis: a morphometric analysis on pleural mesotheliomas.

In the course of the last years digital image analysis has become increasingly important in the field of quantitative pathology. This may be due to the technical development of computers which have now reached a high user-friendly standard. In the present paper we present: (1) the development of a simple system for the measurement of digital image analysis; (2) the development of a general data structure applicable to various measurements and classification strategies; and (3) the analysis of the value of invariant moments (IM) as regional descriptors to distinguish mesothelial cells from mesothelioma cells in cytologic smears of pleural fluid. The results show that the invariant moments contain information concerning the geometric distribution of the grey values of the pixels as well as the staining intensity. The invariant moments present combination parameters and are therefore ideal morphometric parameters. With the invariant moments 7 out of 7 patients with mesotheliomas and 8 out of 11 control subjects could be assigned correctly in a nonparametric discriminant analysis procedure.

Cell Nucleus↗
PubMed1989

Prognostic significance (relapse, non-relapse) of nuclear shape parameters in lymph node negative breast cancer.

A series of 15 postmenopausal patients with stage I invasive breast cancer (pT1-2, pNO, cMO) of uniform histologic type (ductal, NOS) was selected from the Basel Cancer Registry for retrospective analysis. A group of seven patients with a minimal disease-free survival of 9 years was compared to a group of eight patients with clinical and/or histopathological relapse within 8 years of mastectomy. Computer-assisted morphometry of cancer nuclei in routine histological material was used to investigate possible correlations of clinical outcome with nuclear size and shape parameters. Significant differences were found for certain shape descriptors by nonparametric statistical analysis. Stepwise discriminant analysis was applied to find the best combination of parameters separating the two prognostic groups. Application of the 'leaving one out method' showed correct classification in 6 of 8 recurrent cases and in all non-recurrent cases. The number of patients is small, therefore the results should be carefully interpreted.

Breast Neoplasms↗
PubMed1987

A semiautomatic image analyzing system based on an APPLE II or IIe personal computer.

A new semiautomatic image analyzing system based on an APPLE II or IIe personal computer is described. The configurations of the hardware and software are extensively explained. The possibilities of applying the system are demonstrated by different examples taken from various projects in biological research and clinical pathology. The system is designed to fulfil the following requirements: (1) stepwise realization as a unit-by-unit system according to individual needs and interests, (2) acquisition and calculation of morphometric parameters, (3) provision of solutions for the greatest possible number of given problems in clinical and experimental pathology, (4) direct connection of the system to host computers for on-line data transfer and evaluation, and (5) optimum cost-benefit ratio by manifold application possibilities for the individual hardware and software elements. The advantages of the unit-by-unit system with personal computers outweigh in many respects the disadvantages (for example, increased file handling and limited capacity) in comparison with the closed automatized image evaluation system, particularly with regard to costs, flexibility and compatibility. The system is being further developed in collaboration with Kontron Bildanalyse GmbH, Eching/Munich, FRG.

Animals↗
PubMed1987

Morphometry and immunocytochemistry.

The use of morphometry (and stereology), especially in conjunction with immunocytochemistry, in surgical and experimental pathology is reviewed. The combined use of morphometry and immunocytochemistry permits the study of secretory products and the distinction between cells that produce them, e.g., as in the pancreas. Several examples to illustrate the application of immunocytochemical techniques in morphometry are presented. For example, using this approach on the pancreas, it was shown that not only B cells, but also A and D cells, seem to undergo pathologic changes in a prediabetic organism. Since morphologic alterations may be distributional as well as quantitative, a model for the assessment and statistical evaluation of the distribution of objects within an area is discussed. Similar procedures were used to analyze the distribution of cytochrome P-450 molecules along intracellular membranes; however, special labeling techniques were necessary for this quantification in the electron microscope. Immunoenzyme cytochemically stained secretions can also be studied morphometrically, and microdensitometry and microfluorometry can also be used to quantify immunocytochemical reactions, as is shown in the analysis of the intralobular distribution of NADPH-cytochrome P-450 reductase in the rat liver. Finally, the BIVAS semiautomatic system for morphometric measurements, developed at the Department of Pathology of the University of Basel, is briefly described.

Animals↗
PubMed1987

Analysis of object clustering.

Objects of a given type lie on a plane or in a thin layer. In the analysis of the arrangement of such objects, the question may arise as to whether these objects form clusters or whether they are randomly distributed. This question can be answered by the calculation of the coefficient of dispersion (CD) of the objects. Some statistical properties of this coefficient, i.e., its sensitivity and its chi-square approximation, are analyzed in this paper. The proposed approach for calculating sensitivity is a mathematical simulation that is not generally applicable but is valid in various biologic applications. Assuming that the objects are much smaller than the expected clusters and that no knowledge exists about interactions among the objects or between the objects and their surroundings, the objects can be assumed to be distributed randomly on the plane. Such situations may occur in various fields, i.e., biology, sociology, archaeology and ecology. The authors have applied this approach successfully in investigating the densities of T-cell lymphocytes in renal transplants treated with Cyclosporin A or conventional immunosuppressive therapy.

Computer Simulation↗
PubMed1979

Monoamine oxidase inhibiting and toxic effects of acetyl-phenylhydrazide on rat liver in vivo.

For induction of reticulocytosis, rats had been routinely treated with the haemolytic agent, acetyl-phenylhydrazide (APH), and monoamine oxidase (MAO) activity was determined in reticulocytes. Since hydrazines are known to be irreversible inhibitors of MAO, the MAO inhibiting potency of APH was assessed in vitro and in vivo. Only in vivo, an apparently organ-selective MAO inhibition was observed in rat liver; in addition, the rate of recovery of MAO activity in vivo after inhibition with APH was considerably prolonged, indicating a toxic effect of APH on this organ. However, clinical-chemical and pathohistological parameters did not reveal any signs of an overall liver parenchymal cell damage. Hence, a more specific interference of APH with mitochondrial enzyme synthesis must be postulated.

Animals↗
PubMed1976

[Lung neoplasms in the Berne region. Epidemiology and smoking habit, compared to histology].

223 lung cancer patients were observed from June 1974 to April 1976. The diagnosis was by histology (after biopsy, operation or autopsy). There were 125 (56%) squamous cell carcinomas (sqcc), 42 (19%) small cell carcinomas (smcc), 27 (12%) large cell carcinomas (lacc) and 29 (13%) adenocarcinomas (adec). There were only 6 women (2.7%) in the series (3adec, 2 smcc and 1 lacc). Heavy and very heavy smokers were common in each group; smoking habits--even of patients with adec - differed markedly (p less than 0.0005) from those of an age and sex matched control group of 90 asthmatic patients with atopy. Sqcc patients were evenly distributed over the rural and urban zones of our region. But smcc, lacc and adec were more often seen coming from urban zones (p less than 0.0025). The whole lung cancer group was divided into a small group of 6 non-smokers (2.7%), into a 6.7% group of 15 pipe smokers, into a large group of 69 cigar smokers (30.9%) and into a final group of 133 (59.6%) cigarette smokers. The cigar smokers usually had sqcc (p less than 0.0005). The cancer of cigar smokers is more often a central lesion than a peripheral one (p less than 0.025). A history of repeated airway infections on the one hand, and severe airway infection at the beginning of lung cancer history on the other, are a more frequent association in cigar smokers than in cigarette smokers (p less than 0.01). Therefore, the lung cancer of cigar smokers is especially difficult to recognize. Cigar smoking appears to be just as important a link in the chain of causative factors leading to lung cancer as cigarette smoking.

Adenocarcinoma↗
PubMed1976

Cardiomegaly in neonatal hypoglycemia.

Chest X-rays of 24 hypoglycemic newborns were compared with those of a matched control group of newborns with normal blood glucose levels. In the hypoglycemic group heart size was found to be significantly greater than in the control group. No correlation could be established between the degree of cardiomegaly and the severity of hypoglycemia. 19 of the 24 hypoglycemic children were prematures or small for dates and it is postulated that the low glycogen stores in these infants do not meet the metabolic demands of the myocardium during its postpartum circulatory adaptation.

Cardiomegaly↗