Biomedical subjects
A Hecht
Publications and source records attributed to A Hecht.
[Modern theoretico-cognitive problems of medical science].
The paper presents the opinion that the medical science supported by theoretical generalizations is directed to mastering its scientific cognition, which will enable medicine to reach theoretical levels. In theoretical pathology, it is essential, as the first step, to define the concept of a disease in terms of dialectical materialism, to develop the concept of human disease, to apply the principles of dialectical determinism in a step-by-step fashion, to be critical in using reductionism and related scientific substantiation of strategies to solve health problems.
[Arteriosclerosis over time].
Arteriosclerosis is a process over time. It is described with reference to its historical dimension, evolution, aspect of comparative anatomy, and autonomy. The need is emphasized for examining this process in its discontinuity, with a view to realizing the variable nature of causative relationships at different stages of the disease. It is of particular interest to clear up the factors responsible for progression of the arteriosclerotic process. In this context, attention should be focussed at the process of aging and its importance to arteriosclerosis in interaction with exogenous noxae.
[Arteriosclerosis as the reflected image of current problems of medical science].
Predominance of analysis over synthesis, lack of integrative perception and inadequate consideration of regulatory mechanisms, insufficient understanding of the dialectical relationship between animal and man as well as of human individuality, these are considered to be the most severe limitations on scientific cognition today. This appraisal fully applies to arteriosclerosis, as well. More attention ought to be given to its peculiarities as a chronic disease, to the role played by so-called risk factors and their causative implications as well as to the impact of senescence on chronic pathological alterations. Our present knowledge on the causative correlations implied is not sufficient for adequate prevention of the arteriosclerotic vascular disease. Nevertheless, it would make sense to reduce those factors which have been identified as risk-boosting, although only limited consequences can be expected from such an approach.
Rat antibodies as probes for the characterization of progesterone receptor A and B proteins from laying hen oviduct cytosol.
The chicken oviduct contains two different hormone binding forms of the progesterone receptor, A and B. We have prepared rat antisera against both forms of the receptor partially purified from laying hen oviduct. The anti-progesterone receptor A antiserum reacts with both receptor forms on Western blots, while the anti-progesterone receptor B antiserum reacts mainly with the B form. Both antisera also react with the native progesterone receptor proteins as shown by sedimentation analysis of the antibody-receptor complexes. Receptors A and B are recognized on Western blots of total protein from dissolved tissue, indicating that both forms are likely to be physiological components. Epitope mapping experiments show that immunogenicity of both receptor molecules is restricted to structurally related protein domains of 28 kDa in receptor A and of 52 kDa in receptor B.
A progesterone responsive element maps to the far upstream steroid dependent DNase hypersensitive site of chicken lysozyme chromatin.
We have investigated the influence of the 5'-flanking region of the chicken lysozyme gene on steroid dependent gene expression. By transient transfection of lysozyme-CAT fusion genes into the human breast cancer cell line T-47D, a DNA element was identified which stimulates CAT expression when transfected cells are treated with progesterone. This element is distinct from a second hormone responsive element (HRE) located in the lysozyme promoter region; it activates the lysozyme and the TK promoter, irrespective of orientation and distance, and is therefore referred to as hormone responsive element on its own. The location of this newly discovered HRE between -2250 and -1815 relative to the transcriptional start site, corresponds to the position of a steroid inducible DNase I-hypersensitive site in chromatin of oviduct cells. This observation suggests a physiological role for the upstream element. In vitro DNase I protection experiments revealed six binding sites for both progesterone and glucocorticoid receptors within the sequences of the upstream HRE. The three distal binding sites are not required for hormonal stimulation of the TK promoter, while the three proximal binding sites, which are contiguously arranged, work in a cooperative manner.
Histoautoradiographic detection of 3H-thymidine and 3H-proline in the vascular wall of domestic swine in experimental atherosclerosis. Is there an effect of saturated/unsaturated fatty acids in high cholesterol diet?
In vitro labeling of arterial wall samples from domestic swine with tritiated thymidine or proline was used to establish the effect of unsaturated (sunflower oil) or saturated (beef tallow) fatty acids in the presence of enteral cholesterol on DNA and collagen synthesis. Histoautoradiography of samples incubated in vitro gives labeling patterns and indices comparable to in vivo labeling. Preliminary results show that these nutrient fats do not differ in their effect on the DNA and collagen synthesis of vascular wall cells both in the presence and absence of intimal changes.
[The future of pathological anatomy and the paradigms in science].
The view is taken that the future of pathology can be perceived only in relation to the development of science in general and medical science in particular. Development of science should be seen in the dialectics of continuity and discontinuity. The power of this process depends on dialectic antagonisms, such as those between being and appearance, development of medical science and even more of biological science, and techno-scientific progress. Taking this in consideration, no principal change of trend in issues and methodology may be expected in pathological anatomy. However, differences will grow between the theoretico-experimental and clinical aspects of pathological anatomy.
The influence of dietary low and high unsaturated fats and cholesterol on the fatty acid pattern of serum and aortic cholesteryl esters and the lipid deposits of pig aorta.
16 three-month-old female pigs were divided into 3 groups. 6 animals received a semi-synthetic diet containing 15% sunflower oil (g/100 g food) and 1.25% cholesterol (SF group). In 6 animals the sunflower oil was replaced by beef tallow (BT group). 4 control animals 1.5% sunflower oil and without cholesterol. The serum cholesterol levels of the SF group rose moderately, those of the BT group moderately or highly. The relative lipid infiltrated intima area (LIA) and the cholesteryl ester (CE) content of aortas were generally lower in the SF group than in the BT group in comparison to the serum cholesterol levels. The dietary fatty acid pattern determined the fatty acid composition of CE in the serum and extracellular lipid of the aortic lesions. With regard to the intracellular changes of fatty acid pattern of CE (decrease in dienoic acid, predominantly linoleic acid, and increase in monoenoic acids, predominantly oleic acid, and in trienoic acids and higher unsaturated fatty acids), there were important differences between the 2 dietary groups. The dienoic acid content of CE decreased intracellularly from 61% to 30.5%, at the most, in the SF group, and then stopped. In the BT group only 26-35% dienoic acid was available from the extracellular CE and was reduced intracellularly to 9% at the most. In the SF group the intracellular increase in monoenoic acid content of CE was related to the decrease in dienoic acid content. In the BT group this was true only for some lipid deposits of the aorta; in other lesions the monoenoic acid content remained nearly constant or even decreased with decrease in linoleic acid whereas the increase in trienoic acid content was especially high suggesting that an unphysiological trienoic acid (20:3 delta 5, 8, 11), originating from oleic acid, was formed in greater amounts. Our findings point to the development of an essential fatty acid deficiency in the foam cells of aortic lesions in the BT group which may result in an unfavorable influence on the cholesterol clearance from the cells and the arterial wall.
[Disease and its course considered from a causative point of view].
The need is substantiated for differentiation between the process and course of a disease. The course of a disease may be variable, depending on critical conditions and causative factors at the beginning. Differentiation is necessary between acute and chronic diseases as well as between expected and unexpected courses (complications) of a disease. Consideration must be given to the classical differentiation between restitutio ad integrum, restitutio cum defectu and death. Special interest is focussed at the chronic disease and its relationship with the process of ageing.
[Determining the meaning of the concept of etiology].
The standpoint is taken that the understanding of causality in the medical science needs a precisation of its substance. In analyzing a number of textbooks of general pathology, beginning with the middle of the 19th century, the views of leading pathologists to this problem are reviewed. In consequence of this analysis an increase of cognition to the problem of etiology is to recognize. But it seems necessary to define the ideas on this field in using the dialectic determinism. This belongs to the following objects: etiology, causal and formal pathogenesis and causality. Using the term etiopathogenesis seems not to be efficient. In contrast the term of pathogenetic acting principal seems to be useful, but precisation of its substance is necessary.
[Problems in the classification of disease--historical and current aspects].
Based on the general principles for classifying objects and its significance for science, and analysis of the current most important principles of classification in pathological anatomy is undertaken. In this context 6 groups of signs are presented which seem useful for the classification of diseases. The tendency to change from an artificial to a more natural mode of classification is described. A combination of these two aspects seems to best satisfy the actual needs. Special attention should be concentrated on general etiology and its relation to dialectic determinism. Of great importance is to consider new knowledge on the significance of DNA for the classification of diseases. The idea of disorders of metabolism is outdated and the chapter on disturbances of growth and differentiation must be divided according to the underlying defect.
[Pathological anatomy--past, present and future].
Beginning with a brief overview of its history the future developments of pathologic anatomy are anticipated. While the major tasks of the institutes of pathology in hospitals lie in clinical pathology, the emphasis of the university institutes is on teaching and communicating the basis of general pathology and pathological anatomy. Progress requires a more intensive development of experimental and theoretical research as well as new morphologic techniques, taking advantage of recent scientific and technical advances. Clinical pathology should not be among the primary goals of university institutes. One of their major tasks must be the elaboration of cognitive theoretical concepts to further develop the understanding and classification of diseases and neoplasias, and their complex etiologies. The relationship with other medical disciplines is discussed. Pathological anatomy at universities should reflect the spirit of Virchow's pathology as is obvious from its history and traditions.
[Dialectic of the disease concept].
Using the Marxist concept of matter as the point of departure, a short description is given of life as a principle moving form of matter. Life is the structured, biological, moving form of matter which has developed from the single cell, over different stages of organization to the human being. Disease too, represents a fundamental manifestation of life and has also been subject to the process of evolution and arises as a reaction to the confrontation with the environment. Its characteristics take on a different quality depending on the level of organization of the living organism. For this reason there can be no universally inclusive definition of disease which applies to all forms of life. In particular concepts of human disease must take into account the social form of matter in movement. In the same way the biological characterization of human disease must consider the micro-molecular point of view. Correspondingly malignant neoplasms for example are human diseases in the usual clinical sense but biologically are distinct in that, like aging they are directly bond to the existence of DNA. Both from the perspective of theoretical cognition and from the practical standpoint, such distinctions are essential to the way in which the concept of disease is regarded, if errors in the assessment of disease are to be avoided.
[The variable disease process--biologic conditions and theoretical scientific aspects].
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[Introduction to current problems in arteriosclerosis research].
Preliminarily is referred to essential aspects of the aetiology of arteriosclerosis with particular consideration of the disturbed lipoprotein metabolism. Morphologically in the centre of pathogenetic considerations is the behaviour of the endothelial cells, the smooth muscle cells and the blood macrophages. As in many cases open problems we refer to the different participation of various arterial parts of the vessels in the arteriosclerotic process, to the necessity of a further clarification of the role of the thrombocytes in the initial phase of the arteriosclerosis as well as to the monocytes and their possible importance for the elimination of lipids from the vascular wall, the influence of drugs on the proliferation of smooth muscle cells and the formation of extracellular matrix, the question of the regression of arteriosclerotic changes, the reduction of risk factors and their influence on the regression of morphological changes in various developmental stages of arteriosclerosis. It is referred to the possible importance of macrophages and their metabolism as markers for the recognition of risk-endangered persons. Furthermore is emphasized the importance of models for the clarification of the pathomechanism of the arteriosclerosis as well as of the cell culture and of perfusion models.
[Significance of a theoretical pathology for the scientific cognitive process in medicine].
A critical examination of current trends in medicine demonstrates the need for a deepened theoretical foundation. Of particular importance is the development of theoretical pathology. The goals, methods and content of theoretical pathology are discussed and contrasted with those of general and special pathology. Although general pathology incorporates some elements of theoretical pathology, the latter is based on the theory of cognition rather than empirical science. Dialectic materialism is an essential element of this discipline. The development of theoretical pathology demands an interdisciplinary approach on the part of physicians, natural and social scientists and must be based on a broad concept of human disease.
[Cognitive aspects and problems in the diagnosis of malignant tumors and their integration into a general disease concept].
The view is expressed that the histologic diagnosis of malignant tumors rests on criteria which only partially reflect the true nature of the process. Future development will require a broadened basis for histologic tumor diagnosis. Immunohistochemistry will play an important role. Further as yet undefined methodologic advances are to be expected. Tumor development, like aging, may be regarded as a fundamental biological event and an expression of complex alterations of the genome. It would be a simplification to regard it merely as a manifestation of disturbed growth and differentiation processes. The current oncogen theory represents a useful contribution but is not a complete explantation of tumorgenesis. A definition of malignancy is proposed which incorporates our current understanding of essential aspects and which is distinct from general concepts of disease and from other DNA-related disturbances of development, such as congenital enzyme defects and genetically determined malformations.