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Biomedical subjects

W Hermanns

Publications and source records attributed to W Hermanns.

At least 91 records · Page 5Linked to original sources
PubMed1989

Adverse effects of the antifertility agent DL 717-IT (Canocenta, Byk Gulden, FRG). Pathological findings in the rabbit.

The post-coital antifertility agent DL 717-IT (Canocenta, Byk Gulden, FRG) was administered to sixteen female (5 pregnant and 11 nonpregnant) New Zealand White (NZW) rabbits by single i.m. injections at a dose of 2.5 mg/kg body weight. The corresponding number of controls received the vehicle of the drug only. Pregnancy was interrupted in all the DL 717-IT-treated rabbits. Obvious loss of bodyweight (-15% at mean) was observed in all the test animals during the first two test weeks after treatment. Same sized groups of test and control animals were euthanasized 3, 4, 5, and 6 weeks after the initiation of the treatment and complete necropsies and histological examinations were performed. One of the test animals died on day 21. Pathological findings involved epidermal hyperplasia, hyper- and dyskeratosis seen in 16/16, zonal and massive liver necrosis in 8/16, generalized degeneration of the skeletal muscles in 6/16, and focal myocardial necrosis in 5/16 test animals. Vitamin A concentrations in liver tissue were found to be significantly reduced in the experimental animals compared to the controls. Consequently the skin lesions may possibly be explained as the result of reduced vitamin A synthesis due to DL 717-IT-induced hepatocellular damage. The results of this study indicate severe toxic effects of DL 717-IT in the given formulation in the rabbit at dosages reported to be well tolerated in several species and recommended for veterinary use to terminate unwanted pregnancies in the bitch.

Abortifacient Agents↗
PubMed1988

[The pathogenesis of erysipelas arthritis].

Experimental chronic erysipelas polyarthritis in rat, induced by living erysipelas bacteria, histologically can be divided into four different phases. In the phase of population bacteria are distributed diffusely within the whole joint but accumulate in the transitional zones and entheses by multiplication within the ground substance of cartilage. In the phase of acute destruction a severe inflammation of all joint tissues predominates. Bacterial antigen is eliminated by a pannus tissue destroying the cartilaginous structures. In the following phase a diffuse dystrophy of articular cartilage dominates. The reason for this process is not clear; within the cartilage bacterial antigen can seldom be demonstrated, but it accumulates intracellularly in the periphery of the joints (e.g. dense connective tissue, muscles). In the chronic phase we find a lymphoplasmacytic infiltration of the subsynovium, a lining cell hyperplasia, and pannus formation arising from the epiphyseal bone marrow cavity. The relation between chronic inflammation and destruction in the central and antigen persistence in the outer parts of the joints is a matter of current investigation.

Animals↗
PubMed1987

Identification of osteoclasts and their differentiation from mononuclear phagocytes by enzyme histochemistry.

A double staining method is presented which allows the enzyme histochemical differentiation between osteoclasts (mono- and multinucleated forms) and mononuclear phagocytes (macrophages, multinucleated inflammatory giant cells). Osteoclasts are characterized by a strong acid phosphatase activity whereas macrophages and inflammatory giant cells show a variable non-specific esterase activity. The described method may be useful in studying the osteoclast origin and the extraosseous distribution of these cells.

Acid Phosphatase↗
PubMed1986

Ia antigens in plastic-embedded tissues: a post-embedding immunohistochemical study.

The aim of the present study was to establish a plastic embedding technique that makes possible the immunohistochemical demonstration of class II major histocompatibility complex (MHC) antigens (Ia antigens) in undecalcified joint tissues. Therefore a series of fixatives and dehydrating agents was tested for saving Ia immunoreactivity by post-embedding immunostaining of thin sections (2 microns) of rat tissues that had been embedded in glycol methacrylate (GMA), and by comparing with cryostat sections. An indirect immunoperoxidase and the avidin-biotin complex (ABC) technique were used. Combined with fixation by 4% formaldehyde, dehydration with GMA was found to give the best preservation of Ia antigenicity, followed by dehydration with ethylene glycol. The thinness of tissue sections facilitated the association of Ia antigens with different subcellular compartments in distinct cell populations. These various patterns are described.

Animals↗
PubMed1985

Borderline-tissues as sites of antigen deposition and persistence--a unifying concept of rheumatoid inflammation?

In organs of rheumatoid inflammation avascular tissue is nourished by perfusion either directly from the blood stream or by neighbouring blood vessels (borderline-tissue). An open question remains whether this borderline-tissue promotes only the known antigen persistence, or also the first deposition of the pathogenetically important microbial antigen, and subsequently a deposition of immune complexes. The three markers (carbon, latex, and living bacteria) used in this study led to nearly the same pattern of deposition in two groups of organ systems: Organs with clearance function belonging to the mononuclear phagocyte system (MPS); organs with borderline-tissues: joint, kidney, artery, heart valve, and eye. This deposition at the borderline can be observed best in areas of the joint where highly vascularized tissues are adjacent to avascular tissues nourished via perfusion: perichondrium, peritendineum, periosteum, and endo- and perimysium. These localisations of particle deposition correspond exactly with the intraarticular predilection sites of chronic rheumatoid inflammation in man and animals. Our results indicate an easier settlement of corpuscular material in these localisations, which at the same time are unable to eliminate such substances, unlike the organs of the MPS. Our studies seem to support the theory of pathogenetic importance of the borderline-tissues as a localizing factor in the perpetuating rheumatoid inflammation.

Animals↗
PubMed1985

Application of the indirect enzyme immunoassay for the detection of antibodies against Erysipelothrix rhusiopathiae.

Sera from swine and rats experimentally infected with Erysipelothrix rhusiopathiae and field sera from swine were investigated for antibodies against E. rhusiopathiae using the microtiter enzyme immunoassay (EIA) and, for comparison, the growth test (GT) and the agglutination test (AT). In principle there was a good correspondence between the results of EIA and those of the two other methods, but EIA and GT were more sensitive than AT. On the basis of the evaluation pattern of GT and AT on swine sera, EIA titers of 1/320 were considered as "chronic erysipelas titers". Compared with GT and AT, the EIA has some advantages: it is not influenced by contamination of the test sera, it takes only a few hours and using the microtiter system it is easy and economical to perform.

Agglutination Tests↗
PubMed1983

Studies of polyarthritis caused by Mycoplasma arthritidis in rats. I. Detection of the persisting Mycoplasma antigen by the enzyme immune assay (EIA) and conventional culture technique.

Investigations on Mycoplasma (M.) arthritidis polyarthritis of the rat produced by intravenous inoculation of M. arthritidis ISR 1 with special reference to the persistence of the inoculated mycoplasma antigen were performed in a total of 145 rats. The mycoplasmas were demonstrated by the conventional culture technique as well as by an enzyme immune assay (EIA). M. arthritidis was cultured from liver, kidney, spleen, and thymus up to 4 days, from trachea and uterus up to 4 weeks, and from lung, heart, brain, and lymph nodes up to 2 months after infection. It could be recovered from the joints in 70-80% of the animals up to 28 days and in the remaining 20-30% up to 200 days after infection. Using the EIA the mycoplasmal antigen could be demonstrated generally, also in the joints of infected rats which had no longer been positive by culture (10-20 weeks after inoculation). The investigations using EIA also showed a positive reaction between antiserum against M. arthritidis and joint homogenates of control rats, indicating the presence of common antigens to M. arthritidis and to joint tissues of the rat.

Animals↗
PubMed1983

Studies of polyarthritis caused by mycoplasma arthritidis in rats. III. Histopathological findings.

Mycoplasma arthritidis induced polyarthritis in the rat is characterized histologically by four distinct phases. Firstly, two days after infection, early lesions such as vascular changes and alterations in the lining cell layer of synovium are observed. This is followed four days after inoculation by an acute exudative phase with the deposit of fibrin and infiltration by polymorphonuclear granulocytes together with first signs of joint destruction by pannus-like granulation tissue. From about the third week onwards, lymphocytes and plasma cells predominate in the subsynovium, indicating subacute inflammation. In the fourth phase which lasts until the end of the one year observation period, chronic arthritis with destruction of cartilage and bone, ankylosis, and chronic inflammation, sometimes with acute recurrences, were observed in about 25% of the joints. Both the marked tendency to pannus formation and the longevity of the arthritis, make this an interesting, experimental model of chronic polyarthritis, particularly as it has been induced by a peptidoglycan-free microorganism.

Animals↗