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Biomedical subjects

J Plendl

Publications and source records attributed to J Plendl.

29 records · Page 2Linked to original sources
PubMed1993

Organ-specific change in Dolichos biflorus lectin binding by myocardial endothelial cells during in vitro cultivation.

Endothelial cells of the NMRI mouse strain express a cell surface glycoprotein recognized by the lectin Dolichos biflorus agglutinin (DBA). This study documents a marked organ-specific increase in DBA-specific lectin binding of myocardium-derived endothelial cells (MEC) of the NMRI/GSF mouse during in vitro cultivation. An up to 20-fold increase in DBA binding sites is observed in long-term culture, an increase not found in other NMRI-derived endothelial cell lines (e.g., brain, aorta). The increase appears restricted to DBA in that binding with other lectins (PNA, WGA) was unaltered. NMRI MEC cultures maintain typical endothelial cell attributes such as cobblestone morphology on confluence, expression of endothelial cell-specific surface markers, and production of angiotensin-converting enzyme. Cultures routinely become aneuploid within 4 passages, several passages before upregulation of the DBA binding site(s). Myocardial endothelial cells sorted to obtain DBAhi and DBAlo cell populations generally maintained their sorted phenotype for 3 to 4 passages. Limiting dilution cloning resulted in clones varying in DBA expression. Clones for DBAhi expression maintained their DBA affinity for at least 10 passages (> 30 doublings), whereas DBAlo clones gave rise to varying numbers of DBAhi cells within 2 to 4 passages. We hypothesize that the change in DBA affinity accompanies in vitro aging, that the change is independent of alterations in karyotype, and that the increase in DBA affinity may reflect a change in one or more other endothelial cell properties. Additional studies will be necessary to determine whether the in vitro changes are correlated with specific functional alterations and whether they accurately reflect progressive changes of MEC in vivo.

Animals↗
PubMed1992

Sexual dimorphism of the kidney in the NMRI mouse as shown by Dolichos biflorus agglutinin labelling.

The histological affinity pattern of Dolichos biflorus agglutinin (DBA) in kidneys from mice (NMRI, Balb/c, CBA) and rats (Wistar) fixed by perfusion with formalin, Bouin, or HgCl2 was investigated with a horseradish peroxidase conjugate. The animals were examined from fetal stage to adulthood. Adult female NMRI mice exhibited constant DBA labelling, with DBA binding to cells of the proximal and collecting tubules. Moreover the vascular endothelium of the renal papilla was found to be DBA-positive in 50% of adult female animals. In contrast, there was only very little DBA binding in the kidneys of male adult NMRI mice. There was no sexual dimorphism in lectin labelling in kidneys from other strains of mice or from rats.

Animals↗
PubMed1992

[The heterogenicity of the vascular endothelium].

The vascular endothelium has long been considered to be a homogeneous cell type. It is only recently that its remarkable heterogeneity has been shown. The selective and organ-specific adhesion of cells of the immune system, of metastasizing tumor cells and of microorganisms underscores the central position of the endothelium between the circulation and each organ. The use of antibodies and lectins led to the recognition of species-, organ-, and age-specific endothelial cell surface receptors. Identification of the endothelial adhesion molecules and -mechanisms, which are part of the "endothelial organ- and tissue address" would lead to the possibility of blocking the adhesion of cells, such as e.g. tumor cells.

Animals↗
PubMed1989

Long-lasting effects of naltrexone, an opioid receptor antagonist, on cell proliferation in developing rat forebrain.

Several studies have demonstrated in the past that endogenous opioid peptides and opioid receptors may be involved as mediators of brain tissue growth and function in the neonate. Applying histological and autoradiographic methods, we have examined the effect of the mu-receptor-specific antagonist, naltrexone, on the proliferation of the 4-12-week-old rat forebrain subependymal layer. We found that naltrexone, when given daily throughout the weaning period, evoked a long-lasting increase of the mitotic rate and the [3H]thymidine labelling index. This effect was most significant about 8-10 weeks after ending the naltrexone treatment. Although a direct influence of naltrexone on long-term subependymal cell proliferation cannot be excluded, we are discussing evidence of an indirect effect via suppression of noradrenergic activity in the forebrain.

Animals↗
PubMed1989

Lectinhistochemical study of cell surface alterations in mouse embryos exposed to low radiation doses.

The peroxidase-coupled Dolichos biflorus agglutinin (DBA) served as a marker for cell surface alterations in embryonic mouse tissues exposed to low-dose radiation during the early organogenesis (day 9 post conception). In unirradiated embryos, DBA bound selectively to various organ primordia, depending on their differentiation state. The auditory vesicles and the developing blood vessels were the only tissues staining strongly with the lectin. The vascular endothelia also showed the highest radiosensitivity, expressed by the maximal reaction already at 12.5 cGy. Marked surface changes as well were registered in the basal part of the Rathke's pocket and in the roof of the diencephalon. After exposure to 25 cGy, a transient amplification of the reaction as compared with 12.5 cGy occurred firstly in the Rathke's pocket, then in the infundibulum and in auditory vesicles. The most distinct effects were achieved with 50 cGy. Remarkable is the prompt rise of the DBA-affinity in a narrow area of the myelencephalon, and subsequently also in the roof of the diencephalon. Furthermore, the infundibulum and the Rathke's pocket, both anlagen of the pituitary gland, bound heavily DBA during the entire examination period of 24 h. The present study demonstrated the outstanding suitability of the Dolichos biflorus agglutinin for histochemical detection of subtle cellular alterations by small radiation doses.

Animals↗
PubMed1989

The effect of fetal irradiation on the growth of postnatally xenotransplanted tumour cells.

Exposure of the mouse fetus (NMRI-strain) to 1.0 Gy X-irradiation has a marked effect on postnatally xenotransplanted glioma cells. In comparison to non-irradiated animals, irradiation on gestation day 14 resulted in: (a) a significantly higher rate of animals which failed to develop visible tumours growing from the inoculum; (b) a significant inhibition of the growth rate of solid gliomas; (c) a pronounced granulocytic and mast cell infiltration, and tissue necrosis, in the invading gliomas. The results suggest that irradiation in prenatal life exerts an amplifying effect on the antitumour response in postnatal life.

Animals↗
PubMed1988

Dolichos biflorus agglutinin: a marker of the developing olfactory system in the NMRI-mouse strain.

The binding of horseradish peroxidase-labelled Dolichos biflorus agglutinin (HRP-DBA) to the olfactory system of NMRI-mice was investigated histochemically during the pre- and postnatal period. DBA bound with high affinity to a group of olfactory receptor neurons of both the olfactory epithelium proper and the vomeronasal organ from gestation days (g.d.) 14 and 15 onward respectively. Furthermore, there was also extensive binding to axon bundles and to the glomeruli of the main and accessory olfactory bulbs. In addition, DBA-binding was observed in goblet cells and some glands of the nasal septum. From g.d. 17 onward the number of DBA-positive neurons increased significantly and the glomeruli within the olfactory bulbs became DBA-reactive for the first time. Concomitantly, the endothelium of vessels within the olfactory epithelium's submucosa lost its DBA-affinity, though the respiratory submucosal vessels still remained DBA-positive. Possible interrelationships between DBA-affinity of blood vessel endothelium and the neighbouring olfactory neurons are discussed.

Animals↗
PubMed1988

[The variability of the surface morphology of olfactory sensory receptors].

The olfactory epithelium of the adult hamster (mesocricetus auratus) was examined by light- and scanning electron microscopy. Tissues were perfusion-fixed in buffered glutaraldehyde solution. Of particular interest were the regionally varying, thickly structured olfactory boarder and the polymorphic olfactory receptors. The forms varied from simple, smooth olfactory vesicles to highly differentiated receptors with up to 20 cilia of varying length per vesicle. The cilia were tapered at such a rate that the distal segments had an average diameter 1/2 to 1/3 of the proximal segment. The distal segments were arranged in a parallel fashion occasionally over more than 100 microns in length between the surface of the epithelium and the loose meshlike plexus of the olfactory border. A second receptor type was also frequently observed in which the surface area was increased through microvilli. These variations in the structure of the receptors are discussed with regard to new immunohistochemical results. Further experiments should determine the relationship of local morphological differences.

Animals↗
PubMed1987

Effects of naltrexone in postnatal rats on the recovery of disturbed brain and lymphatic tissues after X-irradiation or ethylnitrosourea treatment in utero.

The role of endogenous opioid systems in preweaning development after intrauterine exposure to X-irradiation or ethylnitrosourea (ENU) was explored in rats using naltrexone, a potent antagonist of beta-endorphin. After daily s.c. injections of 50 mg/kg naltrexone only the prenatally untreated controls had body weights increased by 11% from control level on day 28 (weaning). In the X-irradiated as well as the ENU-treated pups no significant effects of naltrexone on body weight gain were observed. However, brain weight increased in all animals under the influence of naltrexone, irrespective of prenatal treatment or the severity of brain lesions: 9.5% above control values in untreated offspring and 14% after X-irradiation (1 Gy) on gestation day 14. The brain weight of ENU-treated rats (50 mg/kg on gest. day 14) was 13% higher after postnatal naltrexone application than that of their postnatally untreated counterparts. ENU (80 mg/kg) effects on the brain when given on gestation day 18 were ameliorated to 9.2% by naltrexone in the weaning period. Naltrexone significantly increased the thymus weight in controls. Prenatally treated animals also showed an increased thymus weight at weaning, presumably due to compensatory growth. In these cases naltrexone revealed a suppressive effect on the thymus, whereas spleen weight was apparently not influenced by naltrexone treatment. These results provide compelling evidence that endogenous opioid systems play a crucial role not only in normal development, but also in reparative growth events of the brain after prenatal injuries. The thymus, predominantly containing T-lymphocytes, seems to represent another sensitive system which is regulated under the influence of opioids.

Aging↗
PubMedDate not supplied

Role of basic fibroblast growth factor in prostatic tumors.

Compared with normal prostatic tissue, the level of basic fibroblast growth factor (bFGF) is elevated in prostatic tumors. This suggests that bFGF may play a role in the development of prostatic neoplasms. The current study was undertaken to identify the cellular distribution of bFGF in benign prostatic hyperplasia (BPH) and prostatic carcinoma using a polyclonal antiserum against recombinant bFGF. In paraffin sections of prostatic tumors immunoreactive bFGF was found in fibroblasts, smooth muscle cells, and endothelial cells. Distinct staining was seen in most nuclei of these cells and a less intense immunoreaction occurred in the cytoplasm of smooth muscle cells. No immunostaining was seen in prostatic epithelial cells of prostatic tumors whether benign or malignant. With digoxigenin-labeled oligonucleotides in nonradioactive in situ hybridization, the presence of mRNA for bFGF was shown in smooth muscle cells of the stroma, suggesting that these cells are the main source of bFGF in BPH. Because no immunostaining for bFGF was obtained in the carcinoma cells, a specific role for bFGF cannot be seen for the development of malignant prostatic tumors.

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