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A Niendorf

Publications and source records attributed to A Niendorf.

54 records · Page 3Linked to original sources
PubMed1989

Effect of continuous vs intermittent application of 3-OH-tamoxifen or tamoxifen on the proliferation of the human breast cancer cell line MCF-7 M1.

The antiproliferative potency of 5 x 10(-7) M tamoxifen (TAM) and 3-hydroxytamoxifen (3-OH-TAM) was investigated during continuous (8 days) or intermittent (2 h every 2nd or 3rd day, respectively) application to the oestrogen-receptor-positive, estradiol-sensitive human mammary carcinoma cell line MCF-7 M1, a variant of MCF-7 wild type. Growth modulation was evaluated in parallel by counting cells and by measuring DNA content. Continuous incubation resulted in a growth inhibition to 21.8 +/- 3.2% by 3-OH-TAM and to 39.5 +/- 4.8% by TAM when compared with control cultures defined as 100%. Intermittent addition induced a growth reduction to 23.0 +/- 2.1% by 3-OH-TAM and to 41.2 +/- 2.4% by TAM in relation to 100% controls. Addition of 3-OH-TAM for 2 h only at day 1 resulted in an inhibition to 70.3 +/- 3.2%, again in relation to 100% controls. When TAM was administered once for 2 h at day 1 it induced an inhibition to 79.0 +/- 4.9% at day 8. The in vitro results indicate that (a) at 5 x 10(-7) M 3-OH-TAM has a better antiproliferative effectiveness than TAM, (b) the intermittent application is as effective as continuous application (no significant difference), and (c) the addition once a week reveals only a slight growth reduction after 8 days of culture. Application of the long-living TAM results in continuously high serum concentrations, which have been shown to create resistant cell clones. Compared to TAM the 3-OH metabolite has a considerably shorter half-life and its application in vivo reveals rise and fall of its serum concentrations. Since the presented data demonstrate that 3-OH-TAM is more potent than TAM and that the intermittent application is as effective as the continuous form, interval therapy with 3-OH-TAM may slow down the process of acquiring resistance to antioestrogens.

Breast Neoplasms↗
PubMed1988

Effectiveness of mitoxantrone on the proliferation of cell cultures derived from malignant mesenchymal tumors of human origin.

The antiproliferative potency of mitoxantrone (MITOX) has predominantly been established for epithelial and hematologic neoplasias. In this study the effectiveness of MITOX was investigated in vitro for 6 sarcomatous human cell lines derived from 2 synovial sarcomas, a malignant schwannoma, a malignant histiocytoma, a leiomyosarcoma, and a chondrosarcoma. The examination was performed using a proliferation assay with monolayer cell cultures. The effect of MITOX was compared with that of adriamycin (ADR) and cisplatin (CDDP). For each drug at least 3 concentrations were tested which covered the therapeutically achievable range, i.e., for MITOX 0.2-0.002 micrograms/ml, for ADR 0.5-0.005 micrograms/ml, and for CDDP 5.0-0.05 micrograms/ml. Test incubations were performed for 3 days. Antiproliferative potency of the cytostatic drugs was assessed by counting the number of cells at the start and the end of the test period with and without drug addition. Furthermore the dose inhibiting cell growth to 50% of controls (ID50) was determined for MITOX. For comparison 4 cell lines from carcinomatous lesions were included in the study. MITOX inhibited proliferation rates of 4 sarcomatous tumor cell lines more intensively than ADR, and was less effective in 2 cell lines. However, these differences were not significant. In all mesenchymal cell lines tested the antiproliferative potency of MITOX was more pronounced than that of CDDP. In carcinomatous cell lines the MITOX-induced growth inhibition was similar to that found in response to administration of ADR and CDDP confirming the described effect on epithelial tumors. The study suggests that MITOX possesses a growth inhibitory potency for malignant soft tissue tumors in vitro. From these data it may be worthwhile to initiate clinical trials testing the treatment of sarcomatous lesions with MITOX.

Adolescent↗
PubMed1988

DNA cytophotometry in malignant thyroid tumors--use of different evaluation schemes for prognostic statements.

Quantitative evaluation of nuclear DNA has been found to provide information on diagnosis and prognosis in a number of malignant tumours and borderline lesions. Using 53 carcinomas of the thyroid with varying differentiation we examined the prognostic information obtained by DNA cytophotometry with respect to clinical outcome, applying three different evaluation schemes. DNA cytophotometry allowed the discrimination of euploid carcinomas with good prognosis from aneuploid tumours with bad prognosis and a generally shortened life span. However, the encapsulated variants of follicular and papillary thyroid carcinomas, with their generally excellent prognosis, exhibited DNA histograms similar to those of their widely invasive counterparts. Thus, the favourable prognosis of these minimal invasive subtypes may primarily be related to the tumours' encapsulation and cannot be ascribed to a particular DNA content. We conclude that DNA cytophotometry can provide additional prognostic information for the individual patient suffering from thyroid carcinoma and may probably lead to an individualization of the therapeutic strategies.

Adenocarcinoma↗
PubMed1988

A novel method to demonstrate parathyroid hormone binding on unfixed living target cells in culture.

We present a rapid and specific procedure that enables one to identify living target cells of peptide hormones within heterogeneous cell populations by means of morphological demonstration of ligand-receptor binding. This is exemplified using a biotinylated parathyroid hormone (PTH) analogue (biotinyl-b-PTH 1-84) which reacts with avidin-fluorescein (avidin-FITC) as a histochemical marker. The experiments revealed a fine dot-like distribution pattern of binding after 1-5 min of incubation at room temperature, changing to a more clustered pattern after 10 min of incubation. Competition of labeled and unlabeled PTH exhibited lack of staining if unlabeled PTH was applied in excess. The results suggest that the demonstrated binding sites represent specific receptors for PTH on living target cells.

Animals↗
PubMed1987

Establishment of primary cell cultures: experiences with 155 cell strains.

Cell culture systems allow the examination of cell populations in a functional state. To simulate in vivo conditions as closely as possible freshly established cell strains are superior to permanent cell lines. Different aspects for the establishment of primary cell cultures obtained from various tissues are compared: Disintegration, culture media supplemented with basal additions, special supplements (growth factors, hormones), and attachment factors. The proliferation rates of the attained cell strains were evaluated by determination of cell doubling times. Procedures for how to obtain a relatively high plating efficiency (approx. 70% in our series of 219 attempts) of primary growth in vitro are described: (1) Mechanical disintegration is superior to enzymatic digestion. If mechanical treatment alone did not produce a sufficient number of viable cells, additional digestion with collagenase/dispase revealed a higher number of proliferating primary cultures than with trypsin. (2) Proliferation of cell cultures from normal and tumorous tissues of epithelial origin was superior in Leibovitz L 15 medium (58 of 87 (67%) cases). Cultures from mesenchymal tissues and tumors were found to have shortest cell doubling times in MEM and RPMI 1640 (16 of 23 (70%) cases). The media were supplemented with the basal additions indicated. (3) In approx. 30% of the cases special supplements like growth factors or hormones increased cell replication, although they were almost always not essential for cell growth. (4) Attachment factors only rarely contributed to the initiation of primary monolayer cultures. The application of various culture conditions does not lead to a protocol optimal for all tissues, for all probes of the same type of tumor, or for all tumor specimens of unique differentiation.

Cell Adhesion↗
PubMed1987

Effect of 1,25-dihydroxyvitamin D3 on human cancer cells in vitro.

1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) dependent growth and differentiation of 6 tumor cell lines has been determined by the use of the monolayer proliferation assay. Cell lines of 4 gastro-intestinal carcinomas, 1 malignant schwannoma, and 1 malignant histiocytoma have been established and characterized. Cells were incubated for 4, 7, and 11 days in the presence of 0.8 or 8 nM 1,25(OH)2D3 and for control without addition of the hormone. Proliferation rates of 1,25(OH)2D3 treated cells were compared with cell growth in the untreated controls. Five out of 6 cell lines showed a 1,25(OH)2D3 dependent growth pattern. With 8 nM 1,25(OH)2D3 they were all inhibited. With 0.8 nM, 3 of them were inhibited at any time of the test period, whereas 1 was stimulated at day 4 and inhibited at days 7 and 11. One cell line was stimulated at days 4, 7, and 11 when incubated with 0.8 nM 1,25(OH)2D3. No striking morphological changes could be observed in the presence of 1,25(OH)2D3. We conclude that 1,25(OH)2D3 dependent cells in vitro are not necessarily growth-inhibited by this compound. Thus, 1,25(OH)2D3 is not an exclusively proliferation inhibiting agent.

Antigens, Neoplasm↗
PubMed1987

Abnormal calcium distribution in human parathyroid adenomas as possible cause of primary hyperparathyroidism.

Current knowledge suggests that normal parathyroid glands and parathyroid adenomas have different sensitivities to environmental calcium. In search for morphological equivalents, 5 normal human and 10 porcine parathyroid glands, as well as 10 human parathyroid adenomas were investigated with regard to intracellular and extracellular calcium distribution. The glands were incubated for 2, 4, 6 and 20 h in tissue cultures using HAM's F10 medium with various calcium concentrations. For visualization of the calcium distribution in the tissue the method of pyroantimonate precipitation was applied. Specificity of the reaction was controlled by X-ray microanalysis. Shifts of the calcium pyroantimonate precipitates were quantitated by morphometry using an area-counting system. The results demonstrate that in normal parathyroid glands calcium precipitates are distributed randomly. Incubation of normal glands in medium with low calcium concentration (0.6 mM) provoked reduced amounts of intracellular and extracellular calcium complexes. When the incubations were performed in medium with high calcium content (2.6 mM), calcium accumulated inside parathyroid and stroma cells. In contrast to normal parathyroid glands, parathyroid adenomas fixed immediately after surgery showed an atypical calcium distribution with low amounts of intracellular and high amounts of extracellular calcium grains. The data suggest that in normal parathyroid glands the intracellular calcium concentration follows the extracellular environmental calcium concentration. Thus, calcium modulates parathyroid hormone (PTH) secretion via intracellular regulatory mechanisms. In parathyroid adenomas the calcium transport via the tumor cell membrane appears to be disturbed resulting in lowered intracellular calcium levels. This is remarkable since the environmental calcium concentration is elevated due to the hypercalcemia of primary hyperparathyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1987

Immunoreactivity of PTH-binding in intact bovine kidney tissue and cultured cortical kidney cells indicative for specific receptors.

Localization of PTH-binding sites has been examined in intact kidney sections and cultured cells derived from bovine kidney cortex. Tissue sections were incubated with 10(-7) M bovine PTH (1-84) for 2 h, cells for 15 min, at 37 degrees C. Visualization of PTH-binding was achieved by immunocytochemistry using a carboxy-terminal specific anti-PTH antiserum (S 478). For control, cell culture incubations were performed applying competitively 10(-7) bovine PTH (1-84) and a 10-fold excess of synthetic 1-34 PTH fragment, not antigenic for S 478. This resulted in a lack of staining. PTH-binding was found in all cells of the proximal and the distal tubule, and with less intensity in the thick ascending limb of Henle's loop. In collecting ducts a PTH specific staining was also present, which was confined to single cells localized between others without PTH binding sites. No staining was seen in glomerula, the thin limb of Henle's loop, in blood vessels, and in connective tissue. The data suggest that large parts of the nephron contain PTH-binding sites, although in different amounts. This is in agreement with the numerous actions of PTH in the kidney. In the collecting segment a distinct cell-to-cell difference was disclosed indicative for different functional states or cellular heterogeneity.

Animals↗
PubMed1987

Co-localization of parathyroid hormone and secretory protein-I in bovine parathyroid glands: a double immunocytochemical study at the electron microscopical level.

Secretory protein-I (SP-I), also known as chromogranin A, is an acidic glycoprotein of unknown function that is found in large amount in the secretory granules of all endocrine and neuroendocrine cells, but not in exocrine or epithelial cells. It is cosecreted with parathyroid hormone (PTH) and by immunocytochemical staining has been reported to exist in the same subcellular structures of the gland. In the present study we have used the colloidal gold-double immunocytochemical technique at the ultrastructural level to precisely define the locales of SP-I and PTH in the bovine parathyroid cell. SP-I and PTH were co-localized to the same secretory granules. The patterns for both gold labels were diffuse ones throughout the granule and suggested that there was a general association of SP-I and PTH. There was little or no localization of the SP-I at the secretory granule membrane. The results support the concept that SP-I is responsible for stabilization of PTH within the secretory granules.

Animals↗
PubMed1986

Nuclear DNA content of borderline tumors of the ovary: correlation with histology and significance for prognosis.

Scanning-DNA cytophotometry was applied to Feulgen stained sections of 22 borderline tumors of the ovary (BOT). The DNA content was related to conventional histology. In 11 cases clinical follow up for more than 5 years was available. The DNA measurements disclosed two subgroups in the group of BOT. One showed a nuclear DNA content not exceeding tetraploidy (4c) indicating proliferative activity without malignant change and a second one exhibited DNA values higher than 4c indicating malignant transformation. Correlation of histological evaluation with the DNA content revealed a good agreement in 15 cases. However, a discrepancy was found in 7 cases: either the histological evaluation aroused suspicion for malignant potential but the histogram showed DNA values not higher than 4c (n = 4), or histology showed well differentiated lesions with an atypical histogram (n = 3). Clinical monitoring revealed no recurrence or tumor spread in all but one case of the group of lesions with DNA values up to 4c, whereas in the group with atypical DNA histograms (DNA values greater than 4c) relapse appeared in 6 out of 7 cases. The results suggest that DNA analysis has prognostic significance for BOT.

Cell Nucleus↗
PubMed1986

Morphological demonstration and quantification of TSH binding sites in neoplastic and non-neoplastic thyroid tissues. An autoradiographic study using 125I-labelled thyrotropin.

We have developed a morphological method to portray TSH binding sites in intact tissue specimens. Frozen sections were incubated with 125I-labelled TSH so as to localise binding sites by autoradiography. The proof of specificity was substantiated by: the competitive inhibition of 125I-TSH-labelling with cold TSH, the lack of binding in non-target tissues and a lack of binding in TSH target tissues after incubation with 125I-hCG or free 125I. In applying this method to a total of 22 surgical specimens of thyroid, striking differences came to light in respect of the degree to which 125I-TSH binding occurred in the various thyroid disorders. When compared with histologically normal tissue, labelling was generally decreased in toxic adenomas, non-functioning adenomas (cold nodules), and thyroids affected by Graves' disease, whereas non-toxic colloid goitre cases clearly exhibited denser binding. Medullary and anaplastic carcinomas exhibited no specific labelling whilst binding varied in the differentiated carcinomas between no effective binding or a level resembling that found in normal thyroid tissue.

Autoradiography↗
PubMed1986

Visualization of binding sites for bovine parathyroid hormone (PTH 1-84) on cultured kidney cells with a biotinyl-b-PTH (1-84) antagonist.

Parathyroid hormone (PTH) receptors have been found in a subpopulation of kidney cells. In this report, we investigated the feasibility of techniques that apply a partial antagonist of PTH conjugated to biotin to localize receptors cytochemically on bovine kidney cortical cells in monolayer culture at the light microscopic level. Biotinylated bovine PTH (1-84) (biotinyl-PTH) was bound to the cultured cells for 1-30 min at 37 degrees C in the amounts of 10(-5) -10(-10) M. In a different set of experiments, the cells were also exposed to a solution containing 10(-6) M biotinylated PTH and an excess of unlabeled PTH, insulin, adrenocorticotropin, or calcitonin for 10 and 30 min at 37 degrees C to test the specificity of the binding. The cells were then fixed in 2.5% glutaraldehyde and stained with the avidin-biotin peroxidase complex (ABC) technique. Diffuse labeling was evident on 30% of the cells in 10 min with concentrations of biotinyl-PTH as low as 10(-8) M. The stain was diffuse, but more intense after 1-10 min in higher concentrations (10(-6) M). If a 15-1500-fold excess of unlabeled PTH was added to the biotinyl-PTH, no staining was observed. The other peptides (insulin, ACTH or calcitonin) had no effect on binding. Longer times in biotinyl-PTH (10(-6) M for 10-30 min) resulted in intense patches of label on the cells resembling caps (in addition to the pale diffuse label). The percentage of labeled cells in the monolayer (30%) did not change with time. These studies show that a partial antagonist of PTH can be used as a cytochemical probe for specific PTH receptors in a subpopulation of cultured cortical kidney cells.

Animals↗
PubMed1986

Cytochemical studies of corticotropin-releasing factor (CRF) receptors in anterior lobe corticotropes: binding, glucocorticoid regulation, and endocytosis of [biotinyl-Ser1]CRF.

A new synthetic biotinylated N-terminal analog of CRF was used to study its binding, endocytosis, and route of processing. The new analog was fully bioactive compared to rat(r) CRF in an ACTH bioassay and pituitary membrane receptor assay. In 1- to 4-day cultured pituitary cell monolayers, CRF receptors were labeled for 1-biotinylated rCRF (1-bio-CRF) and demonstrated with avidin-fluorescein (Ar-Fl) in living cells or with avidin-biotin-peroxidase complex (ABC) in fixed cells. The percentages of fluorescein-labeled cells were comparable to those stained with the ABC technique. The specificity of binding by 1-bio-CRF was shown by the ability of unlabeled CRF to inhibit staining, whereas 100 nM arginine vasopressin, angiotensin II, or somatostatin was without effect. Treatment of the cells with 100 nM glucocorticoids for 1 or 24 h before the 3-min stimulation with 1-bio-CRF caused a 50-60% reduction in the percentage of cells stained with either ABC or Av-Fl. Pretreatment with vehicle, a lower dose of corticosterone (10 nM), or other steroids (dihydrotestosterone or epitestosterone) did not decrease the percentage of cells stained with the ABC technique. The lower dose of glucocorticoids decreased the stain with Av-Fl by 50% after 1 h of pretreatment. Electron microscopic analysis of binding and endocytosis of 1-bio-CRF stained with the ABC technique showed patches of stain on coated pits and microvilli during the first 3 min of exposure. Internalization in vesicles and receptosomes was also seen during the first 3 min. Some stain was found on secretion granules as early as 1 min after exposure. Five minutes after exposure, the stain was in receptosomes, Golgi cisternae, condensing vesicles in the transreticular Golgi region, and 23% of the granules in the cytoplasm. During the later exposure periods (15-30 min), stain was also seen in multivesicular bodies. The correlative light and electron microscopic studies showed that 1-bio-CRF is rapidly internalized after patching on the surface and is ultimately found in multivesicular bodies or granules. We postulate that these structures are involved in processing or degradation of the ligand.

Adrenocorticotropic Hormone↗
PubMed1986

[Cell receptors].

Explore the source record for details and available documents.

Adenylyl Cyclases↗
PubMed1986

Blood group substance, CEA, and lectins in ovarian tumors.

The presence of the blood group substances A, B, AB, Lea, and Leb and of CEA was demonstrated by peroxidase-antiperoxidase or fluorescein immunohistochemistry in histological sections of normal ovarian tissue and ovarian tumors of varying differentiation. In surface cells of normal ovaries and of benign tumors, blood group substances (BGS) were found in patterns corresponding to the serum blood group type of the patients. BGS were localized exclusively at the apical border of normal cells. CEA was almost always absent. In borderline lesions the presence of BGS was reduced by approximately 13%. The polar differentiation was often lost, and the BGS were unevenly distributed in the cytoplasm. The percentage of CEA-specific staining increased from less than 5% in normal tissue and benign tumors to 15% in mucinous and 10% in serous borderline tumors. Malignant tumors contained altered distribution patterns of BGS and CEA. In contrast to normal ovarian epithelia, BGS positivity was diminished distinctly; the decrease was particularly evident for Leb presence by reduction from 75 to 10%. CEA was observed in nearly 50% of the carcinomas (more often in mucinous than in serous carcinomas). Our study revealed that expression of blood group antigens was related to benign lesions, whereas its loss was associated with a greater malignant potential. Inverse correlations were found for CEA. Thus, immunohistological determination of these marker substances may be applied to tumor prognosis.

Blood Group Antigens↗
PubMedDate not supplied

Detection and quantification of lipoprotein(a) in the arterial wall of 107 coronary bypass patients.

The aim of this study was to determine the extent of accumulation of lipoprotein(a) [Lp(a)] in human arterial wall and to define its potential role in atherogenesis. Biopsies routinely taken from the ascending aorta of 107 patients undergoing aortocoronary bypass surgery were analyzed for lipid and lipoprotein parameters, which were then correlated to serum values. A significant positive correlation was established between serum Lp(a) and arterial wall apolipoprotein (apo)(a) by enzyme-linked immunosorbent assay. High serum Lp(a) also led to a significant increase of apo B in the arterial wall. No significant correlation was found between apo B in serum and aortic tissue. Apo B was found to be partially linked to apo(a) in the aortic extract. Furthermore, apo(a) was found to be intact, as determined by its molecular weight in sodium dodecyl sulfate electrophoresis. This technique also revealed that the apo(a) isoform pattern of aortic homogenate was comparable to the individual serum pattern. Immunohistochemical methods demonstrated a striking colocalization of apo(a) and apo B in the arterial wall, predominantly located extracellularly. Both proteins were increased in atherosclerotic plaques. With density gradient ultracentrifugation, Lp(a)-like particles could be isolated from plaque tissue. This initial study showed that Lp(a) accumulates in the arterial wall, partly in the form of lipoprotein-like particles, therefore contributing to plaque formation and coronary heart disease.

Aorta↗