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Biomedical subjects

J Lindner

Publications and source records attributed to J Lindner.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Investigations on connective tissue metabolism: ageing of the human heart.

In any given phase of the age process, the rates of synthesis and degradation of collagen and other macromolecules are diversely influenced by changes in the respective enzyme activities. This naturally affects and reflects the contents of the intracellular as well as extracellular macromolecules. In our studies, the total contents of desoxyribonucleic acid (DNA), hydroxyproline, hexosamines and uronic acids of the four compartments of the human heart were estimated and plotted against age. The results obtained for DNA showed an initial rapid decline in its content to about the middle of the third decade of life, i.e. around the end of the maturation period. Thereafter, the DNA curves showed a relatively slower decrease until the fifth decade, after which a slight increase was observed during senescence. This holds for both the left and the right sides of the heart. Hydroxyproline levels, on the other hand, remained unchanged in all the different compartments except in the left atrium, where the initial phase of the curve showed a significant drop until the middle of the fourth decade. Hydroxyproline values in the atria were twice as high as in the ventricles, which in turn showed higher levels of hexosamines than uronic acids. Both hexosamines and uronic acids in the atrial walls showed an initial decline followed by a gradual rise during ageing. Contents of uronic acids in the ventricles showed a gradual but steady rise throughout life.

Adolescent↗
PubMedDate not supplied

Aging of liver: morphological and biochemical changes.

Light-microscopically there are no significant age-dependent changes in the liver, due to the slight increase in biochemically determined connective tissue components. Electron-microscopical comparison of young and old animals show a larger size and decreased numbers of liver cell mitochondria in older animals. Collagen synthesis in liver is accelerated during growth, as demonstrated by assay of the [3H] proline incorporation rates and of the specific activity of hydroxyproline, corresponding to a decrease in the prolyl hydroxylase activity with age. The neutral salt-soluble collagen fraction may be regarded as a parameter for collagen synthesis, which is activated during the growth period and then remains constant without age and sex differences. Not much is known about the significance of these changes with increasing age or about their initiating factors, although there are parallel findings for liver intoxication and inflammation.

Adolescent↗
PubMedDate not supplied

L1 mono- and polyclonal antibodies modify cell migration in early postnatal mouse cerebellum.

A major event of nervous system development is the migration of granule cell neurones, during the early postnatal development of the cerebellar cortex, from their germinating zone in the external granular layer to their final location in the internal granular layer. During migration, many granule cells are seen in direct cell-surface contact with processes of Bergmann glia, a subclass of astrocytes. In the neurological mutant mouse weaver, however, migration of granule cells is impaired, probably due to a deficit in cell-cell interactions. To gain insight into the cellular and molecular mechanisms involved in granule cell migration, we have used a modification of an in vitro assay system, previously described by Moonen et al., which displays migratory behaviour in small tissue explants during several days of suspension culture. The aim of this study was to investigate the process of granule cell migration by using antibodies directed against cell-surface components of developing neural cells. We report here that migration of 3H-thymidine-labelled granule cell neurones can be modified by Fab fragments of both mono- and polyclonal L1 antibodies, but not by Fab fragments of polyclonal antibodies prepared against mouse liver membranes, which also react with cerebellar cell surfaces.

Animals↗
PubMedDate not supplied

CD4(+) T-cell responses against the VP1-unique region in individuals with recent and persistent parvovirus B19 infection.

To date cellular immune responses against parvovirus B19 (B19) have not been studied extensively. The aim of this study was to examine the T-cell response against the VP1-unique region as the immunodominant part of the viral structural protein VP1 in individuals with different courses of B19 infection. Therefore, a group of 13 parvovirus-positive probands was separated into subgroups characterized for recent or acute, past or persistent infection by means of the presence of specific immunoglobulin (Ig)M and IgG isotypes and of viral DNA in blood and tissue. Transiently transfected B-cells expressing VP1-unique region were used in ELISpot assays to investigate T-cell responses directed against the VP1-unique region in peripheral blood mononuclear cells (PBMC) of individual donors. Significant numbers of interferon-gamma (IFN-gamma) secreting lymphocytes were detectable in PBMC of all individuals with recent, acute or persistent B19 infection, but not in PBMC of donors with past B19 infection and seronegative individuals. A more detailed analysis of IFN-gamma producing cells by intracellular cytokine staining by flow cytometry revealed, that CD4(+) T cells but not CD8(+) cytotoxic lymphocytes (CTL) were the major subpopulation of IFN-gamma producing cells. These data strongly suggest the need of virus protein production for the maintenance of VP1-unique region-specific CD4(+) T-helper cell responses in B19-infected individuals.

Antibodies, Viral↗
PubMedDate not supplied

[Occupational fields and professional opportunities of German gerontologists--a report based on a survey of the members of the German Society for Gerontology].

The report is based on a written questionnaire sent to the members of the Deutsche Gesellschaft für Gerontologie. The rate of return amounted on average to 45% with all four Sections of the Association well represented. 40% of those who answered claim to be active in the scientific field only, 47% work as scientists and practitioners at the same time, and another 9% dedicate their work to practice only. The span of professions as well as branches of science and their specialities is very broad. It may thus be assumed that member composition is a guarantee for multidisciplinarity. 62% of the members who answered claim to have good career prospects in the profession they represent and in their branch of occupation, i.e. in gerontology/geriatrics or in practical fields of work dedicated to applying such knowledge. Nevertheless, one fifth of the members of this professional association see no professional perspectives in the fields named, although their membership in the Association points to a vested interest. One fifth of the members, not identical with the group referred to above, state that they see no chances of employment in gerontology/geriatrics or their fields of application in the long run, or they refrain from presenting a judgment on the grounds of prevailing uncertainty. Critical comments made concern the situation of gerontology/geriatrics in the Federal Republic of Germany. This branch of science is seen as receiving too little recognition and the degree of institutionalisation reached is judged to be rather unsatisfactory.

Attitude of Health Personnel↗
PubMedDate not supplied

[Age-related changes in cellular activity in organ and tissue cultures of the human cornea].

Human autopsy eyes and material of eyes enucleated by various causes were used to prepare explants of the whole chamber angle and isolated stroma corneae for organ and tissue cultures. The age-related changes in chamber angle explants are obscured by interactions of the different cell types. In 75 human stroma explants aged from 5 weeks to 93 years the latent period for cell activation (i.e. the time needed for the activation of cells revealed by histological methods) shows its lowest values in cases under 20 years of age. The latent period for outgrowth of cells is not significantly related to age. The long-term reorganization of the tissue structure in the explants is disturbed in higher age.

Adolescent↗
PubMedDate not supplied

[Skin changes in advanced age--biochemical findings corresponding to morphology?].

The clinically relevant morphological changes of the skin during aging can be summarized by the term "senile atrophy". The changes are a diminished thickness of epidermis with a reduced mitosis rate of epidermal basal cells, shortened and attenuated rete ridges, reduction of epidermal appendages, and a decreased number of fibroblasts and capillaries in the dermis. Corresponding to these morphological findings regarding the cell number in the senile skin (cutis) we found a slight decrease in the DNA concentration of human and rat cutis. The specific DNA activity (3H-thymidine incorporation rate related to DNA concentration) decreased in presenile versus adult animals. The mesenchymal changes in the dermis have been morphologically described by the term "senile elastosis" or "elastoid collagen degeneration", but in fact they correspond to a progressive collagen denaturation with aging. The total collagen concentration, here determined as the hydroxyproline concentration in the human cutis, shows almost constant values from the 3rd until the 9th decade of life in both sexes. This is also true for the skin of two different rat strains. The insoluble collagen fraction shows a relative increase to the disadvantage of the soluble collagen fractions, which can be interpreted as an indicator of a decelerated collagen turnover. In spite of the decelerated turnover, i.e. a prolonged half-life of the collagen metabolism in the skin, the indicators of the collagen neosynthesis (14C-proline incorporation rate, specific hydroxyproline activity, prolyl-hydroxylase activity) are significantly elevated in the cutis of presenile versus adult rats. Any connection of these findings with a possible change in the distribution of collagen types in the senile skin (e.g. pericapillar fibrosis with increase of collagen type I as well as changes in the distribution of type I, III, IV and V) can only be discussed at present. The glycosaminoglycans in the cutis show a minimal increase of the total content of hexosamines and uronic acids with a significant shift in the ratio of the glycosaminoglycan components in favour of dermatan sulfate and keratan sulfate and to the disadvantage of hyaluronic acid and partly also of chondroitin-4-sulfate and -6-sulfate. The neosynthesis of sulfated glycosaminoglycans (indicator method: 35S-sulfate incorporation rate) is only slightly increased whereas the enzyme activities being specific for the glycosaminoglycan catabolism (beta-glucuronidase, beta-N-acetyl-glucosaminidase) are significantly decreased with aging of the skin.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylglucosaminidase↗
PubMedDate not supplied

[Age-related changes in cell content (DNA) and glycosaminoglycan-degrading enzymes (beta-glucuronidase, beta-N-acetylglucosaminidase of connective tissue and parenchymal organs of the rat caused by 6-methylprednisolone (enzyme induction, adaptation, acceleration of maturation and possible modification of aging].

This paper is based on previous investigations, which had shown an evident acceleration of maturation and enzyme induction in several organs, not only in the lung, due to a pre- and postnatal application of prednisolone. Applying the same dosage we now investigated whether there is a similar effect of a short-term application of prednisolone in mesenchymal and parenchymal organs of young adult and presenile rats of the same strain (Chbb: THOM/SPF) analyzing the physiological cell regeneration (DNA concentration) as well as functional parameters of the glycosaminoglycan metabolism (e.g. the lysosomal enzymes beta-glucuronidase and beta-N-acetylglucosaminidase). The results show a significant age-dependent decrease of the DNA concentration (lung, spleen, skin, and rib cartilage), a significant age-dependent decrease of the total activity of the beta-glucuronidase (kidney, rib cartilage, and skin) or a significant age-dependent increase of this enzyme activity (spleen and liver) respectively as well as a significant decrease of the beta-N-acetylglucosaminidase activity (skin and rib cartilage) or a significant increase of this enzyme activity (spleen and lung). After application of prednisolone the rats showed a significant reduction of the DNA concentration only in the skin of young adult rats, but no changes in the other organs of the young adult or presenile animals compared to untreated controls. Similar to our findings after postnatal prednisolone application, we found the greatest increases or decreases respectively of the activities of these lysosomal enzymes due to 2- to 3-fold or 4- to 5-fold prednisolone application. Again similar to our previous findings, we found the phenomena of adaptation and rebound effects including the so-called over-compensation in the young adult and especially in the presenile rats but these effects were delayed and weaker in most of the older animals compared to the young adult rats.

Acetylglucosaminidase↗
PubMedDate not supplied

[Pathology of stroke (= apoplexy)].

In this paper we give a summarizing review of the pathology of apoplexy. Apoplexy is the clinical term for sudden loss of consciousness, followed by paralysis resulting from a cerebral haemorrhage, occlusion of a cerebral artery, thrombosis, or embolism, with loss of cerebral function of the affected brain region. Apoplexy is a very important disease in gerontology and geriatric practice and clinics, since atherosclerosis with cerebral sclerosis, hypertension, and hypertensive angiopathy occur very frequently in the elderly. Besides these main causes of apoplexy aneurysm and other causes of apoplexy are also discussed (i.e. angiomas, primary and secondary "apoplectiform" brain tumors). In this paper only the most important morphological and clinical findings in apoplexy are discussed for general and clinical physicians, giving an introduction to the following contributions in this journal.

Aged↗
PubMedDate not supplied

[The value of morphology in the diagnosis of chronic polyarthritis].

The clinician's question concerning the value of morphological findings in diagnosis of rheumatoid arthritis is answered by the pathologist. After a short discussion of clinical problems and the ARA-criteria, at first the diagnostic importance of synovial cytology in RA is dealt with. The patient's history, biopsy technique and methods are the most important prerequisites of an optimal assistance of the pathologist to a definite diagnosis; they are reviewed in short paragraphs. These data are the bases of the morphological evaluation which is discussed in detail. This is the most important part of the answer to questions of the clinician; the pathologist is not only able to verify the clinical diagnosis of rheumatoid synovitis or of RA but often he may decisively judge the course and activity of the disease and the therapeutic success.

Arthritis, Rheumatoid↗
PubMedDate not supplied

[Autoradiographic studies on the mitotic and productive metabolism of the articular cartilage in mouse genetic arthritis].

With suitable radioactively labelled precursors the mitotic (using 3H-thymidine) and the productive metabolisms (using 3H-proline and 35S-sulphate) were investigated on various kinds of joint- etc. cartilage from mice with genetically caused arthrosis. The autoradiographic analyses were performed using 3H-thymidine-, 3H-proline- and 35S-sulphate-indices and the statistical evaluation of the findings led to the following results: the synthesis level of sulphated glycosaminoglycans (GAG) in the cartilage ground substance is lower for 5--6 month-old mice than for the 16--17 month-old animals of this genetic arthrosis strain. This is most distinct in the 3rd (= basal) zone of the knee-joint cartilage which increased to double the comparable value in this period. In all 3 zones of the knee-joint cartilage GAG-synthesis is considerably greater than the collagen synthesis according to these autoradiographic analyses. These findings can be detected before any histologically or histochemically demonstrable cartilage alterations and represent therefore the earliest signs of a so-called "pre-arthrosis". Collagen synthesis decreases thereby, and the same holds for DNA-synthesis and the mitotic metabolism of the cartilage cells - according to the findings to date. However the question is still under investigation whether arthrosis (like atherosclerosis) also starts with an increase in cell-turnover. This question is not only of theoretical interest, it has practical clinical consequences, even for the treatment. These investigations also serve this clinically relevant question because arthrosis is the most common human joint disease.

Animals↗