Search PubMed⌕ Search

Biomedical subjects

B Zimmermann

Publications and source records attributed to B Zimmermann.

At least 109 records · Page 6Linked to original sources
PubMed1989

Secretion of lamellar bodies in type II pneumocytes in organoid culture: effects of colchicine and cytochalasin B.

Lamellar bodies are the morphological correlate to the alveolar surface-active agent. Diminished synthesis of this surfactant in newborns results in the respiratory distress syndrome. Secretion of lamellar bodies and its dependence on the cytoskeleton are not yet well understood and are still controversially discussed in the literature. We therefore used an organoid culture system of fetal mouse lung cells to investigate electron microscopically secretion of lamellar bodies and influence of both colchicine and cytochalasin B on the secretion process. Secretion of lamellar bodies is to be considered as an eccrine secretion, because no other cytoplasmic components were extruded. It includes a very fast component in opening of the secretory vacuole. Synthesis, but not secretion, was inhibited by colchicine; secretion, but not synthesis, was inhibited by cytochalasin B. Furthermore, formation of the histotypic structures in vitro and deposition of the basal lamina were disturbed by cytochalasin B, but not altered by colchicine. After short-term treatment, these effects turned out to be reversible. The results indicate that synthesis of lamellar bodies depends on an intact microtubular system, whereas secretion requires actin filaments in a functional state.

Animals↗
PubMed1989

[Implantation of porous hydroxyapatite into periodontal bony defects].

The purpose of the present report was to evaluate on a clinical and histological level the effect of hydroxylapatite (HA)--Interpore 200--implanted into various types of periodontal defects. Additionally in-vitro studies with enzymatically released calvarial cells from fetal rats were performed in the organoid culture system. The clinical data 12 months after surgery revealed a greater reduction of probing depths (PD) and gain of attachment level in the implanted sites (59 sites) when compared to the sites treated by open flap curettage (40 sites). When the results were analyzed according to the initial PD the measurements showed no significant difference between the two modalities of treatment in moderately deep pockets (PD less than or equal to 6 mm) in contrast to deep and extremely deep pockets (PD = 7-9 mm and PD greater than 9 mm). In order to collect data about the type of periodontal wound healing biopsies, respectively block sections were taken 6-12 months after therapy in 6 patients and evaluated by light microscopy. Three forms of tissue reaction in relation to the implants were observed. The first consisted of a fibrous connective tissue encapsulation of the implants, the second showed organized bone tissue around the HA, while the third type of tissue reaction consisted of a deposit of mineralized tissue on the surface limited in width, which was interpreted as cementum formation. Analysis of the block sections revealed new connective tissue attachment to a certain extent and bone/cementum-like tissue formation. The possibility of cementum-like tissue formation on HA was confirmed transmission electronmicroscopically by the in-vitro experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Severe aortic stenosis in systemic lupus erythematosus and mucopolysaccharidosis type II (Hunter's syndrome).

Cardiac manifestations of the mucopolysaccharidoses often include valvular regurgitation, but stenotic lesions are quite rare. This report describes a 30-year-old man with mucopolysaccharidosis type II (Hunter's syndrome) and systemic lupus erythematosus who developed severe progressive aortic stenosis and died. Autopsy examination revealed evidence of various cardiac mucopolysaccharide disease including valvular leaflets thickened and distorted with fibrocalcific nodules. A brief review of previously reported valvular disease in Hunter's syndrome and other mucopolysaccharidoses is presented. This is also the first report of a patient with both systemic lupus and a mucopolysaccharidosis.

Adult↗
PubMed1988

Bone formation by rat calvarial cells grown at high density in organoid culture.

Calvarial cells from day 21 rat fetuses were isolated by enzymatic digestion and grown at high density in an organoid culture system at the medium/air interface. In this type of culture, mineralization occurred as early as 7 days in vitro, as revealed by light and electron microscopic means. After about 18 days in vitro, most of the culture consisted of mineralized tissue. Mineralization was also achieved without beta-glycerophosphate, but it was delayed by 2 to 3 days. Maximal alkaline phosphatase activity occurred at days 8 to 12 in vitro and then declined continuously during further cultivation. Two types of mineralization could be observed: (1) mineralization of a collagen-rich osteoid by typical apatite crystals; (2) mineralization of a nearly collagen-free matrix by amorphous material which was possibly secreted by the cells. The importance of higher cell densities for cell differentiation and formation of histotypic tissue in vitro is apparent, and it is indicated that cell-cell contacts and cell-matrix interactions may be prerequisites for the development of histotypic conditions similar to the in vivo situation.

Alkaline Phosphatase↗
PubMed1988

Thrombophilia in blood-donation for plasma- and cytapheresis caused by antithrombin III depletion.

Induced by the case of a blood-donor with more than 100 donations-mostly apheresis-who suffered acute thromboembolism caused by antithrombin III depletion, nearly 60 apheresis-donors were examined before, during and after aphereses, as well manual fourfold as computerized (CS-3000 TRAVENOL) cytaphereses with special methods of coagulation, mainly antithrombin III levels and fibrin-monomeres. The findings were described and compared, multifold in manual techniques happened breaks caused by occluded tubules were accompanied with decrease of antithrombin III and positive FM-tests. It was discussed, if apheresis-techniques for themselves (extracorporal multifold manipulation in manual techniques and contact with artificial surfaces in both kinds of techniques) can be the reason for a hypercoagulation. It seems to be important, how is the situation of apheresis-donor before starting, therefore we give the recommendation, to pay more attention in examination this kind of donors, additional with testing antithrombin III levels and tests for fibrin-monomers.

Adult↗
PubMed1987

Lung organoid culture.

An organoid culture system for lung cells is described in which morphogenesis of lung histotypic structures and differentiation of both pneumocytes type II and mesenchyme occur. The principle of this technique is the culture of mouse fetal lung cells at high density on a membrane filter at the medium/air interface. In the course of cultivation, cell sorting-out, epithelial cell aggregation, formation of an alveolar-like lumen in the organoids and formation of a basal lamina occur. Epithelial differentiation culminates in the production of lamellar bodies, and the mesenchyme develops into mature connective tissue. Morphogenesis and differentiation depend on the stage of fetal development from which the lung cells were derived but appear independent of the formation of a basal lamina. Various drugs have been tested for their effects on morphogenesis and differentiation in this lung organoid culture: some of them inhibit differentiation or damage the mesenchyme, others stimulate surfactant production. Due to the quite complex morphogenetic and cellular events occurring in lung organoid culture, it may be an applicable tool for alternative in vitro screening methods.

Adrenal Cortex Hormones↗
PubMed1987

[Effect of a static magnetic field (3.5 T) on the reproductive behavior of mice, on the embryo and fetal development and on selected hematologic parameters].

To investigate possibilities of magnetic resonance imaging at high magnetic fields in humans, a whole-body magnet with a magnetic field density of 4 T was developed. Due to the few data that are available at present on biological effects and side effects of such high fields, a reproduction experiment with NMRI mice was performed using a crossover design. The mice were allowed to mate during a 7-day period within the field or after their stay in the field. The number of pregnant mice and foetuses were recorded and compared to the controls. Another group was held within the magnetic field during the whole period of pregnancy until day 18, one day before delivery. In all groups, development of the foetuses was studied. Additionally, haematological parameters of the males and females were estimated and necroscopy was performed. Brains, lungs and optical nerves were investigated using pathohistological techniques. It could be shown that in case of mating within the magnetic field, the number of pregnant mice was considerably reduced. This effect was, however, completely reversible if mating occurred after the stay in the field. Malformations, retardations or an increased number of resorptions were never found. The haematological parameters were, in general, not changed. Necroscopy as well as pathohistological investigations showed no pathological alterations. Therefore, it appears that whereas high magnetic fields reduce the activity of mating behaviour, they do not exert any influence on physiological parameters.

Animals↗
PubMed1986

Inactivation of C3a by a monocarboxypeptidase present in culture supernatants of stimulated guinea pig peritoneal macrophages.

Hog C3a, as well as its derivative C3a-desArg were not found to act cytotoxically on starch gel-induced guinea pig peritoneal macrophages. Likewise, neither peptide significantly modified the secretion of N-acetyl-beta-D-glucosaminidase from these cells. However, C3a rapidly lost its spasmogenic activity during incubation in serum-free macrophage cultures and less rapidly in cellfree supernatants collected from cultured macrophages. The following results indicate that C3a is converted into its spasmogenically inactive derivative C3a-desArg by a macrophage-derived monocarboxypeptidase. The inactivated C3a product does not differ from native C3a in sodium dodecyl sulfate-polyacrylamide gel electrophoresis; it elutes from CM cellulose in the same position as purified C3a-desArg; and it is devoid of the carboxyl-terminal arginyl residue of C3a, but still contains the carboxyl-terminal sequence of C3a-desArg as determined by analysis after treatment with carboxypeptidases B or Y. Furthermore, inactivation of C3a in supernatants of macrophage cultures is completely blocked by the specific carboxypeptidase inhibitors guanidinopropylsuccinic acid and 2-mercaptomethyl-3-guanidinoethylthiopropanoic acid in final concentrations of 10 mM and 2.1 mM, respectively. The monocarboxypeptidase is apparently supplied by biosynthesis of new material but is not stored as a preformed enzyme because cycloheximide markedly inhibits its expression.

Acetylglucosaminidase↗
PubMed1986

Role of the N-terminal regions of hog C3a, C5a and C5a-desArg in their biological activities.

The N-terminal regions of the complement peptides C3a, C5a and C5a-desArg (purified from yeast-activated hog serum) were gradually shortened by incubation with leucine amino peptidase. This treatment led to the following changes in the biological activities of these peptides: the potencies of C5a and C5a-desArg in aggregation of human polymorphonuclear leukocytes and of guinea-pig platelets, and their ability to deactivate these cells were gradually diminished; the chemotactic effect of C5a-desArg on human leukocytes was similarly lowered, while the chemotactic potency of C5a was even increased up to the loss of the first 12 N-terminal amino acids. However, after removal of the whole N-terminal region (i.e. 20 amino acids distal of the first disulfide bridge) the potency of both peptides was decreased to a few percent. In contrast, C3a totally lost its platelet-aggregating as well as deactivating activity already after cleavage of 10-15 N-terminal amino acids by LAP. On leukocytes, on the other hand, C3a retained some activity even after the loss of the whole N-terminal region. These results indicate that the N-terminal regions play an important role for biological activities of the three complement peptides, possibly by stabilizing the optimal conformation of their C-terminal regions which contain the receptor-activating domains.

Animals↗
PubMed1986

Binding of various lectins during chondrogenesis in mouse limb buds.

The binding of six different FITC-labelled lectins to cells and matrix was investigated during chondrogenesis in mouse limb buds from day 10 to 13 of development. In undifferentiated mesenchyme, concanavalin A and wheat germ agglutinin bound very strongly, whereas at later stages binding was decreased in the peripheral mesenchyme, but very strong in blastemata and cartilage. Phaseolus vulgaris lectin showed the same properties, but the decrease in the peripheral mesenchyme was less pronounced. Fucose-specific lotus A lectin showed no binding at all. Ricinus communis lectin bound preferentially to the blastemata, and the galactose-specific peanut lectin exhibited binding exclusively to the blastemata. Electron microscopic investigations of the binding of peroxidase-labelled peanut lectin revealed reaction product in the matrix and at cellular membranes only at later stages. Early blastemal cell condensations were negative. In vitro experiments on chondrogenesis in high density cultures showed no pronounced influence of beta-D-galactosides on cell differentiation and matrix production.

Animals↗
PubMed1986

Polyarticular septic arthritis.

Seven adult patients with nongonococcal polyarticular septic arthritis are presented with a literature review of the clinical features of polyarticular bacterial infection. Polyarticular septic arthritis occurred in 19% of reported cases of septic arthritis in adults. Similar to monoarticular disease, the knee was the most commonly affected joint, and Staphylococcus aureus was the most frequently isolated microorganism. Pneumococcus, group G streptococcus, and Hemophilus influenzae had an increased association with polyarticular infection. Five of our 7 patients had underlying rheumatic diseases and the immediate mortality rate was 57%. Review of the literature yielded an overall mortality of 23% for polyarticular septic arthritis compared to the 9% mortality of septic arthritis in general. The subset of patients with polyarticular infection superimposed on rheumatoid arthritis had a mortality rate of 56%.

Aged↗
PubMed1986

Characterization of the synaptosomal high-affinity uptake of noradrenaline in the nucleus accumbens of rats.

In the nucleus (n.) accumbens, a predominantly dopaminergic innervated brain region, a high-affinity noradrenaline (NA) uptake exists indicating NA termination in this area. The affinity of the uptake carrier (Km) is in the range of that given for other regions. For characterizing the specificity of NA uptake, inhibitory experiments of NA and dopamine (DA) uptake were carried out with nomifensine and desipramine. The experiments with desipramine clearly show that the NA uptake is independent of the DA uptake into dopaminergic terminals occurring predominantly in this nucleus.

Animals↗
PubMed1985

Effects of arotinoid ethyl ester on epithelial differentiation and proliferation.

In recent years the search for new retinoids, safer and more potent than the available compounds, has led to the development of arotinoids. In preliminary clinical trials, arotinoid ethyl ester [(E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1- propenyl]benzoic acid ethyl ester; TTNPB ethyl ester] was found to be highly effective in the treatment of severe and etretinate-resistant dermatoses. Using adult hairless mice, embryonic mouse limb-bud cultures and keratinocyte cultures as experimental models, we have performed morphological, autoradiographic and biochemical studies on the effects of arotinoid ethyl ester on epithelial differentiation in vivo and in vitro. Arotinoid ethyl ester stimulates proliferation of both embryonic and adult mouse epidermis. However, it inhibits the differentiation of embryonic epidermis and enhances that of adult epidermis. Arotinoid ethyl ester induces a decrease in the cyclic AMP content of cholera toxin-stimulated keratinocytes but fails to alter cyclic AMP concentrations in keratinocytes not treated with cholera toxin.

Aging↗
PubMed1985

Teratogenicity of arotinoid ethyl ester (RO 13-6298) in mice.

Arotinoid ethyl ester (RO 13-6298) is a new and very potent retinoid that exerts a profound influence on epithelial and mesenchymal differentiation in doses 500 times lower than those of compounds of the first and second retinoid generation. In the present study the teratogenicity of arotinoid ethyl ester was investigated in NMRI mice employing different treatment schedules. Recording of abnormalities was performed on day 18 (day 0 = day of conception) according to Wilson and with cleared skeletal preparations. Intraperitoneal application of the drug at a dosage of 10 micrograms/kg/day for three consecutive days (days 9-11 or 12-14) caused severe malformations, particularly in the skeletal system and the cavernous organs. Skeletal elements were reduced in number, shortened, or abnormally shaped. Ossification was diminished. Atresia of anus and urethra were frequent. Single application of 200 micrograms/kg between days 8 and 14 also caused multiple and severe malformations. However, no stage-specific pattern of abnormalities was detectable. Some skeletal malformations indicated more or less vulnerable stages that were in concordance with special developmental steps. Others, however, seemed to be equally susceptible over a longer period, eg, rays 1 and 5 of the hand or foot and the development of the mandibular joints. The pattern of abnormalities caused by these very low doses of RO 13-6298 is comparable to that obtained with other retinoids and is achieved within the same relative dose-response range. Preconceptional treatment of the animals did not induce any malformations.

Abnormalities, Drug-Induced↗
PubMed1985

Retinoids inhibit the differentiation of embryonic-mouse mesenchymal cells in vitro.

The influence of all-trans retinoic acid, 13-cis retinoid acid and two aromatic retinoids (Ro 10-1670, Ro 11-1430) on the chondrogenic differentiation of mesenchymal cells in vitro was studied electron-microscopically. Organ cultures of limb buds from mouse embryos (Day 11) and high-density cultures of embryonic-mouse mesenchymal cells (Day 12) were used as experimental models. After a 6-day culture in the control medium, the development of hyaline cartilage was observed in both systems. In cultures which were treated with retinoids from Day 1 through Day 3 and then incubated in the control medium for 3 more days, the mesenchymal cells still maintained the morphological features of the blastema stage; cartilage synthesis was reduced (low retinoid concentrations) or completely absent (high retinoid concentrations). These findings indicate that the treatment of embryonic-mouse mesenchymal cells with retinoids induces a persistent and dose-dependent inhibition of chondrogenic differentiation, which in quantitative terms, is variably expressed during treatment with different retinoids. These inhibitory effects of retinoids on chondrogenesis are probably implicated in the pathogenetic mechanisms of their teratogenic action in vivo.

Animals↗
PubMed1985

Effects of monovalent cations on red cell shape and size.

Human erythrocytes were incubated in isotonic solutions of different monovalent cations. The apparent size of the red cells measured on scanning electron microscopic pictures decreases in the order Li+ greater than Na+ = K+ greater than Rb+. These differences in size are abolished after pretreatment with trypsin, which removes a large part of the charges associated with membrane glycoproteins. Shape alterations are also observed. Normal biconcave shapes are visible after Na+ or K+ incubation, whereas Li+ leads to flabby, flattened cells with a certain tendency to crenation, and Rb+ causes more pronounced biconcavity with a certain tendency to cupping. The overall effects of pretreatment with trypsin are similar to those of Li+. Our results provide evidence that the electrostatic repulsion of glycoproteins and other charged membrane components may play an essential role in maintaining red cell shape.

Cations, Monovalent↗