Library

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (28,273)
  • 1970-1974  (15,137)
  • 1890-1899  (8,112)
  • Polymer and Materials Science  (31,976)
  • Inorganic Chemistry  (15,590)
  • Engineering General  (3,633)
  • breast cancer
Material
Years
Year
Keywords
  • 1
    ISSN: 1436-2813
    Keywords: p53 protein ; breast cancer ; lymph node metastasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The p53 expression in invasive breast cancers from 106 patients was correlated with clinicopathological variables to ascertain its usefulness for estimating prognosis. The p53 expression was significantly associated with the number of axillary lymph node metastases and the presence of internal mammary lymph node metastases; however, it was not associated with age, menopausal status, histologic type, or tumor size. Although p53 expression was a significant prognostic factor according to univariate analysis, it did not appear to be an independent prognostic factor according to multivariate analysis. Thus, the prognostic power of p53 expression is likely to be weak and therefore probably of limited clinical value. Nevertheless, the number of patients in our study was small, and we believe that an investigation of a larger series of patients is indicated.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1436-2813
    Keywords: breast cancer ; extended radical mastectomy ; internal mammary lymph node ; multivariate analysis ; metastasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We performed a new type of en bloc extended radical mastectomy (EXT) as a clinical trial in 118 patients from 1980 through 1985. A variety of conventional radical mastectomies (RDL) were also undertaken in 105 patients from 1973 through 1985. In this retrospective study, univariate and multivariate analyses were performed to compare the results of EXT and RDL. The univariate analysis showed that the 10-year survival rates for the EXT and the RDL groups were 86% ± 3.3% and 77% ± 4.2%, respectively (P = 0.073 with the Cox-Mantel test). For the subgroups stratified according to the status of axillary lymph node involvement, the EXT was significantly better in patients with one to three metastatic axillary lymph nodes (P = 0.016). The adjusted Cox regression analysis revealed that the favorable results of EXT were most encouraging in the patients with one to three metastatic axillary lymph nodes (P = 0.058). Therefore, it is suggested that an EXT may be more advantageous than RDL in selected patients with resectable invasive breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1436-2813
    Keywords: breast cancer ; epidermal growth factor receptor ; prognosis ; lymph node metastasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The association between epidermal growth factor receptor (EGFR) expression, clinicopathological variables, silver-stained nuclear organizer region (Ag-NOR) counts, and patient survival was determined in 93 patients with operable breast cancer. The EGFR expression was found to be significantly associated with the presence and number of axillary lymph node metastases (P = 0.0429), but not with age, menopausal status, tumor size, histologic type or grade, or Ag-NOR counts. In a univariate analysis, a significant difference was also observed in the survival of patients stratified by tumor size (P = 0.0091), histologic grade (P = 0.0352), axillarly lymph node metastases (P = 0.0001), and EGFR expression (P = 0.0263). However, a multivariate analysis revealed that axillarly lymph node metastases was the only strong independent predictor ol'survival (P 〈 0.0001). When axillary lymph node metastases were excluded from the Cox model, the EGFR expression tended to be an independent prognostic factor (P = 0.0558). The results of this study thus indicate that the prognostic value of EGFR expression is limited because the EGFR expression is significantly associated with axillary lymph node metastases.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1436-2813
    Keywords: breast cancer ; national survey ; breast-conserving surgery ; geographic variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A nationwide survey in Japan of the patients with primary breast cancer from 1989 to 1991 revealed marked changes in the surgical treatment of the disease. During this period, there was a significant trend toward fewer instances of radical and extended radical mastectomies, and an increase in modified radical mastectomies and breast-conserving surgery. The percentage of breast-conserving surgery for the early-stage disease increased from 6.8% to 12.7%. Among the types of operations for breast-conserving surgery, quadrantectomy was used for 51.5% of the cases, while either a partial mastectomy or a subcutaneous mastectomy was used for 18.2% and 18.9%, respectively; a lumpectomy was performed in 10.9% of the cases. As for the proportion of patients receiving radiation therapy after breast-conserving surgery, 77% of those undergoing lumpectomy received radiation in contrast to only 43% of the patients undergoing quadrantectomy. According to the data from 1991, we also found that breast-conserving surgery was performed more often in larger cities and urban areas in Japan. As a result, we found that substantial changes in the treatment of localized breast cancer had taken place from 1989 to 1991. Regarding the details of breast-conserving surgery, however, some variation still remains in spite of the publication of numerous clinical trials.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1436-2813
    Keywords: breast self-examination ; questionnaire survey ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using a questionnaire survey, we analyzed the relationship between the frequency of breast self-examination (BSE) and the clinical stage and course of breast cancer in Japanese patients. BSE had been performed monthly by only 5.4% of the patients (M group), occasionally by 35.4% (O group), and not at all by 59.2% (N group). There was a positive relationship between more frequent BSE and an earlier clinical stage, the percentages of Tis/stage 0 and I for the M, O, and N groups being 83%, 44%, and 36%, respectively (P〈0.05). The mean maximum tumor diameters for the three groups were 1.7cm, 2.5cm, and 3.0cm, respectively. The tumor size in the M and O groups was significantly smaller than that in the N group atP〈0.01 andP〈0.05, respectively. The percentages of patients in the M, O, and N groups who underwent breast-conserving therapy were 42%, 11%, and 19%, respectively, with patients who had performed monthly, BSE more frequently undergoing breast-conserving therapy (P〈0.05). At a median follow-up time of 34 months, 0%, 3.8%, and 7.6% of the patients from the M, O, and N groups, respectively, had died of breast cancer, the overall survival curve of the M group being significantly better than that of the N group (P〈0.01). This retrospective study suggests the positive correlation of BSE frequency with earlier detection, and a more favorable clinical course in Japanese breast cancer patients.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1436-2813
    Keywords: parathyroid hormone-related protein ; breast cancer ; skeletal metastases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relationship between the expression of parathyroid hormone-related protein (PTHrP) by breast cancer and skeletal metastases, was investigated using a monoclonal antibody against human PTHrP (4133). The immunohistochemical localization of PTHrP was studied in sections of formalin-fixed, paraffin-embeded tissues from 28 breast cancers obtained surgically between 1980 and 1985. Of the 28 patients, 12 developed skeletal metastases, 8 developed lung metastases, and the other 8 were alive and disease-free at the time of this study. Sixteen of the 28 (57%) tumors showed positive immunoreactivity to 4133, the PTHrP positive ratio being 83% in the patients who developed skeletal metastases, 38% in those who developed lung metastases, and 38% in those without recurrence, respectively. Thus, a significantly higher proportion of the patients who developed skeletal metastases were positive for PTHrP than the other two groups (P 〈 0.05). Furthermore, the level of positive staining was strongly related to positivity for estrogen and progesterone receptors (P 〈 0.01). These results are consistent with the hypothesis that PTHrP might be necessary for metastases to erode bone and grow in skeletal sites, and its expression could be related to certain hormones.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of behavioral medicine 17 (1994), S. 523-534 
    ISSN: 1573-3521
    Keywords: breast self-examination ; compliance ; breast cancer ; positions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Psychology
    Notes: Abstract The present study examined compliance with the three recommended breast self-examination (BSE) positions over a 6-month follow-up period. An ongoing behavioral measure that provided information about the type of exam performed during each BSE occasion was employed. Results indicated that adherence to all three position types was obtained in only 40% of the exams. Forty-two percent of exams were comprised of only one position, with the supine position being the most frequently practiced exam type. Implications of these results with regard to BSE research and current breast cancer screening recommendations are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1573-4986
    Keywords: breast cancer ; fucose ; haptoglobin ; ovarian cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract There is increasing evidence for changes in fucosylation in cancer. Previously, we showed that the fucose-specific lectin,Lotus tetragonolobus, extracts an abnormal form of haptoglobin (Hp) from cancer sera. This study investigates the monosaccharide content of Hp obtained from women with ovarian and breast cancer at different stages of their disease. In both cancers, Hp fucose was low when the disease was benign or in remission and much higher when the disease was progressive. This occurred whether the data was expressed per mole of protein or per three mannose residues. Changes in other monosaccharides were minor compared with fucose. There were small increases in theN-acetylglucosamine and galactose content (per three mannoses) in ovarian cancer, suggesting that some glycan chains have increased branching. The latter was independent of disease activity which may be due to some indirect cause such as cytotoxic therapy or an inflammatory response. When ovarian cancer patients were in remission, the number of glycosylation sites on Hp was reduced. Hp isolated from patients with early, but not advanced breast cancer also appeared to have increased glycan branching. The increased fucosylated Hp may interfere with fucose-mediated adhesion reactions of cancer cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1573-0646
    Keywords: cis-platinum ; mitoxantrone ; breast cancer ; phase I-II trial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The Southwest Oncology Group studied the response rate and toxicity of mitoxantrone (7.5 or 10 mg/m2 to 12.0 mg/m2) and cis-platinum (100 mg/m2) in 30 patients with advanced breast cancer as second-line therapy. There were 2 partial responses in 29 eligible patients. Toxicity was considerable, with 27 patients having grade 3 or 4 toxicity. Grade 3–4 toxicity included vomiting, thrombocytopenia, granulocytopenia, leukopenia and anemia. The combination of mitoxantrone plus cis-platinum has minimal activity as second-line therapy in metastatic breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1573-0646
    Keywords: breast cancer ; dipyridamole ; mitoxantrone ; 5-FU ; leukovorin ; chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Based upon the hypothesis that dipyridamole would potentiate the cytotoxicity of mitoxantrone and the combination of 5-fluorouracil (5-FU) and leukovorin, we performed a phase I/II trial of the combination of dipyridamole, 5-FU, leukovorin, and mitoxantrone in patients with metastatic breast cancer. The dose of dipyridamole was fixed at 175 mg/m2 by mouth every 6 h (700 mg/m2/day), based upon a previous phase I trial of oral dipyridamole with 5-FU and leukovorin. Dipyridamole therapy began 24 h prior to the first dose of chemotherapy and continued until 24 h after the last dose of chemotherapy for each course of treatment. At the initial dose level, leukovorin 200 mg/m2 was given intravenously immediately prior to 5-FU 375 mg/ m2 intravenously on days 1–5. Mitoxantrone 6 mg/m2 was given as a single dose on day 3. Unacceptable toxicity was observed at this dose level, leading to successive dose decrements rather than dose increments. The maximum tolerated dose was leukovorin 200 mg/m2 days 1–2, 5-FU 375 mg/m2 days 1–2, mitoxantrone 6 mg/m2 on day 2, and dipyridamole 175 mg/m2 every 6 h on days 0–3. Two responses were produced in 15 patients. This regimen is not recommended for further investigation in the treatment of breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Investigational new drugs 12 (1994), S. 333-336 
    ISSN: 1573-0646
    Keywords: piroxantrone ; oxantrazole ; anthrapyrazoles ; NSC-349174 ; Dup 942 ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Thirty-two eligible patients with advanced metastatic breast cancer who had received no more than 1 prior chemotherapy regimen for metastatic disease (16 had received prior doxorubicin) were treated with piroxantrone at a dose of 120 mg/m2 intravenously every 21 days. In the twenty-seven patients evaluable for response, two partial responses were seen. Toxicities observed were primarily hematologic with grade 3 or greater granulocytopenia occurring in 34% of the patients. One patient developed symptomatic congestive heart failure at a total cumulative dose of 960 mg/m2. We conclude that piroxantrone given at this dose and schedule has minimal activity in patients with metastatic breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 1573-7276
    Keywords: breast cancer ; cell proliferation ; invasion ; migration ; 1α ; 25-dihydroxyvitamin D3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using the Boyden chamber invasion assay, the effect of 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] on the invasiveness of the highly invasive, oestrogen receptor-negative human breast cancer cell line MDA-MB-231 was examined. The MDA-MB-231 cells were shown to contain high-affinity receptors for 1α,25(OH)2D3 with a Kd of 1.5 × 10−11 M. When the cells were treated with 1α,25(OH)2D3 for 4 days before the assay was performed, a dose-dependent inhibition of their invasive potential was demonstrated. Fifty per cent inhibition of invasion was obtained with a concentration of 13 pM of 1α,25(OH)2D3. However, when the cells were treated for only 6 h during the assay, no inhibitory effect was seen. The process of migration was also affected by treatment with 1α,25(OH)2D3 for 4 days, although the inhibition was not of the same magnitude as seen for the invasion. Fifty per cent inhibition of migration occurred at a concentration of 3.2 nM of 1α,25(OH)2D3 (250 times higher than in the invasion assay). Inhibition of invasion and migration was not due to the known anti-proliferative effect of 1α,25(OH)2D3, as no growth reduction could be demonstrated with treatment up to 5 days. Based on the present investigation it can therefore be concluded that 1α,25(OH)2D3 is able to inhibit tumour cell invasiveness by a mechanism which is not exclusively based on its anti-proliferative and anti-migrative effects.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neuro-oncology 21 (1994), S. 159-170 
    ISSN: 1573-7373
    Keywords: paraneoplastic syndrome ; sensorimotor neuropathy ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Paraneoplastic sensorimotor neuropathy occurs in association with many different types of cancer. The clinical findings are heterogeneous, and the pathogenesis is unknown. We have encountered 9 women with breast cancer and shared neurological features that suggest a distinct paraneoplastic syndrome. The syndrome is characterized by upper and lower extremity paresthesias and numbness, itching, muscle weakness and cramps, and in some, radicular symptoms and signs. Serum and CSF inflammatory changes suggested an immune pathogenesis but none had detectable antibodies directed at nervous system elements. Six patients presented with neuropathy 2 months to 8 years before the discovery of the breast cancer. In 7 the neoplastic disease was localized to the breast and axillary lymph nodes. The neurologic course was chronic in all, and while symptoms were annoying, disability was minimal until late. One improved transiently with plasmapheresis, and three had mild transient improvement with treatment of the cancer. Recognition of this paraneoplastic syndrome may forewarn the physician of an underlying breast malignancy.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 14
    ISSN: 1573-7225
    Keywords: A-bomb survivors ; breast cancer ; ionizing radiation ; Japan ; reproductive history
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Three breast cancer risk factors were evaluated in terms of their interactions with radiation dose in a case-control interview study of Japanese A-bomb survivors. Cases and controls were matched on age at the time of the hombings and radiation dose, and dose-related risk was estimated from cohort rather than case-control data. Each factor—age at first full-term pregnancy, number of deliveries, and cumulative lactation period summed over births—conformed reasonably well to a multiplicative interaction model with radiation dose (the additive interactive model, in which the absolute excess risk associated with a factor is assumed to be independent of radiation dose, was rejected). An important implication of the finding is that early age at first full-term pregnancy, multiple births, and lengthy cumulative lactation are all protective against radiation-related, as well as baseline, breast cancer. Analyses by age at exposure to radiation suggest that, among women exposed to radiation in childhood or adolescence, a first full-term pregnancy at an early agefollowing exposure may be protective against radiation-related risk.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 15
    ISSN: 1573-7217
    Keywords: breast cancer ; epidermal growth factor receptor ; estradiol receptor ; progesterone receptor ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a study on 214 patients with primary breast cancer (median follow-up 8.5 yr, maximum follow-up 15 yr), EGF-R was negatively correlated to estrogen receptor and progesterone receptor, whereas no association was found with age, lymph node status, and tumor size. Initially, after a follow-up of 5 yr, there was a tendency to a significant association between EGF-R levels and tumor recurrence rate (p=0.08). Patients with tumors containing intermediate levels of EGF-R experienced a longer relapse-free survival (RFS) than did patients with tumors possessing lower or higher levels of EGF-R. This effect was most pronounced in the subgroup of patients with positive axillary lymph nodes. However, after 10 yr follow-up, this association appears to be lost (p=0.28) as shown in this update. A similar phenomenon was observed for the ER. While at 5 yr follow-up ER status had significant prognostic value (p=0.01), at 10 yr follow-up this significance also appears to be lost (p=0.40). However, tumor size, lymph node status, grade, and PgR status maintained significant prognostic value by univariate analysis. Based on 40 separate studies comprising 5232 patients, the mean percentage of EGF-R positivity reported in breast cancer is 45% (range 14–91%). Nine out of 15 different studies showed in some way a significant negative association between EGF-R and RFS by univariate analysis, and 2 others showed a tendency to such a relationship. Of 7 studies applying multivariate analysis, two demonstrated an independent prognostic value of EGF-R for RFS and two others a tendency to a significant correlation, whereas three did not. It may be concluded that EGF-R status has more or less prognostic value in patients with primary breast cancer, but the prognostic power decreases with longer follow-up. Of great clinical significance is the association of EGF-R with hormone resistance. Therefore EGF-R status can be used for selection of type of treatment. Finally, EGF-R might be useful as a target for new treatment modalities.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 1573-7217
    Keywords: breast cancer ; 1,25-dihydroxyvitamin D3 ; growth inhibition ; MCF-7 ; tamoxifen ; ZR-75-1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present study we assessed the effect of combined treatment with 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) and tamoxifen (TAM) on the growth of estrogen-responsive (MCF-7) and estrogen-dependent (ZR-75-1) human breast cancer cells. Both basal and 17β-estradiol (17β-E2)-stimulated growth were studied. 1,25-(OH)2D3 (10−10 – 10−7 M) time- and dose-dependently inhibited basal growth of MCF-7 cells, with growth arrest at 10−7 M. Also, 17β-E2-stimulated growth of MCF-7 and ZR-75-1 cells was inhibited by 1,25-(OH)2D3 in a time- and dose-dependent manner. TAM inhibited 17β-E2-stimulated growth of both cell lines and at high concentration (10−6 M) it also inhibited basal growth of MCF-7 cells. 10−6 M TAM together with 1,25-(OH)2D3 resulted in a further inhibition of basal (MCF-7 cells) as well as 17β-E2-stimulated proliferation (MCF-7 and ZR-75-1 cells) compared to the inhibition by these agents alone. TAM in combination with 10−7 M 1,25-(OH)2D3 resulted in growth arrest of 17β-E2-stimulated growth of MCF-7 cells. The inhibition of basal and 17β-E2-stimulated growth of MCF-7 cells was additive at early time points (4 days), but less than additive at later time points (8–10 days). It was demonstrated that with co-treatment of MCF-7 cells an equipotent inhibition of basal growth could be reached with lower concentrations of 1,25-(OH)2D3, compared to treatment with 1,25-(OH)2D3 alone. Studies with low concentrations (〈 10−7 M) of TAM revealed a partial estrogenic effect, i.e. stimulation of MCF-7 proliferation in the absence of 17β-E2. This effect, which may resemble TAM-induced tumor flare, was completely prevented by co-treatment with a low concentration of 1,25-(OH)2D3 (10−9 M). Together, these results demonstrate the potent inhibition of breast cancer cell proliferation by 1,25-(OH)2D3 combined with TAM and indicate a potential benefit of combining these agents for the treatment of breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 17
    ISSN: 1573-7217
    Keywords: breast cancer ; prognosis ; gene amplification ; PCR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prognostic value of oncogene amplification and conventional clinicopathological features was determined in consecutive breast cancers detected during 5 months in 1975–1976 in 4 Swedish counties. Material was collected from 162 of the 179 patients and tumor size, nodal status, FSH, estrogen/progesterone receptor status, DNA ploidy and S-phase fraction determined. Tissues remaining from 80 patients were stored frozen until 1991, when amplification of the oncogenes c-erb-B2 and int-2 was determined. We show that c-erb-B2 amplification (but not int-2 amplification) and positive axillary nodal status show prognostic significance for both survival and relapse-free survival in univariate and multivariate analysis. The other examined factors showed no significance.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 18
    ISSN: 1573-7217
    Keywords: breast cancer ; gene amplification ; PCR ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The polymerase chain reaction (PCR) is a powerful tool to examine genetic alterations in tumor samples. We describe a simple, rapid, nonisotopic PCR method to semi-quantitatively determine the number of gene copies in human formalin-fixed paraffin-embedded tissue. The procedure is exemplified by analysis of 15 years old breast cancer samples to determine the presence of amplification of c-erb-B2. The samples were obtained from routine specimens kept in pathological archives. Patients with amplified samples showed a poor prognosis, both for recurrences and death in breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 19
    ISSN: 1573-7217
    Keywords: breast cancer ; carcinoma-associated glycoproteins ; monoclonal antibody 83D4 ; O-glycosylation ; Tn antigen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The Tn determinant (GalNAcα-O-Ser/Thr) is expressed by about 90% of human carcinomas, but is cryptic in most normal human tissues. A murine monoclonal antibody (MAb) 83D4, developed following immunization with human breast carcinoma cells, reacts with a Tn-related epitope. In the present study we characterized the glycoprotein antigen identified by 83D4 in the human breast carcinoma cell line MCF-7. We further showed that the 83D4 antigenic determinant is masked in human milk fat globule membranes (HMFGM), and can be exposed upon mild m-periodate treatment after desialylation. Western-blot analysis resolved the 83D4 antigen from MCF-7 into two main components of 120–190 kD and 〉 500 kD respectively. Non equilibrium pH gradient electrophoresis/SDS PAGE revealed the acidic nature of the reactive glycoproteins (pI 4.43–4.70). 83D4 antigenic activity resolved by CsCl gradient ultracentrifugation layered on a wide range of densities (1.30–1.46 g/ml) including typical densities of mucin-like glycoproteins but also lower densities. The amino acid composition of the antigen, relatively rich in serine but poor in threonine and proline, confirmed the divergence from other mucin-like carcinoma-associated glycoproteins. Dicarboxylic amino acids were abundant, accounting in part for the acidic nature of the molecules. ELISA and Western-blot analysis of the subcellular fractions from MCF-7 cells revealed that the 83D4 antigen is mainly contained in plasma membranes (85%) from which it may be resolved into two broad bands (slow and fast migrating components). These results provide information on a group of breast carcinoma associated glycoproteins related to but different from typical mucins, and provide data on alteration of O-glycosylation in tumor cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 20
    ISSN: 1573-7217
    Keywords: DNA flow cytometry ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ninety-one cases of primary breast cancers and their nodal metastases were examined with DNA flow cytometry. No differences were found between the stemline distributions in the primary tumors and nodal metastases. At both sites stemlines clustered around a DNA index of 1.0 (33–40% of cases) and 1.8. The mean S-phase fractions were 7.9 in primary tumors versus 5.6% in nodal metastases (p = 0.02); this difference was also observed if the analysis was restricted to cases with DNA aneuploidy at both sites (10.2 versus 7.6%, p = 0.04). Our results indicate that axillary nodal ploidy and proliferation reflect primary tumor characteristics rather than displaying changes associated with selection during the lymphatic metastatic process. Lymph nodes may have a suppressive effect on the proliferation of tumor cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 129-138 
    ISSN: 1573-7217
    Keywords: breast cancer ; tamoxifen ; drug resistance ; estrogen receptor mutant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The nonsteroidal antiestrogen tamoxifen (TAM) is the most commonly used endocrine treatment for all stages of breast cancer in both pre- and postmenopausal women. However, the development of resistance to the drug is common, as most patients treated with TAM eventually experience a recurrence of tumor growth. One of the potential mechanisms of treatment failure is the acquisition by the tumor of the ability to respond to TAM as a stimulatory rather than inhibitory ligand. We (Gottardis and Jordan, Cancer Res 48: 5183-5187, 1988; Wolfet al., J Natl Cancer Inst 85: 806-812, 1993) and others (Osborneet al., Eur J Cancer Clin Oncol 23: 1189-1196, 1987; Osborneet al., J Natl Cancer Inst 83: 1477-1482, 1991) have extensively described the reproducible development of TAM stimulated growth in a laboratory model system using MCF-7 human breast cancer cells grown as solid tumors in athymic mice. In this paper we report on the isolation of an estrogen receptor (ER) from a TAM stimulated tumor (MCF-7/MT2) which contains a point mutation that causes a tyrosine for aspartate substitution at amino acid 351 in the ligand binding domain. The mutant appears to the major form of ER expressed by this tumor. We also report that only wild type ER was detected in three other TAM stimulated MCF-7 tumor variants, suggesting that multiple mechanisms are possible for the development of TAM stimulated growth. The implications of these findings are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 117-127 
    ISSN: 1573-7217
    Keywords: breast cancer ; tamoxifen ; drug resistance ; MCF-7 sublives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The non-steroidal antiestrogen tamoxifen (TAM) is successfully used to treat all stages of breast cancer in both pre- and postmenopausal women. Unfortunately, most women treated with TAM eventually develop resistant tumor recurrences which require intervention with a second-line endocrine therapy, or cytotoxic chemotherapy if the recurrence is completely endocrine insensitive. There is evidence that some recurrences may in fact be TAM stimulated. MCF-7 human breast cancer cells grown as solid tumors in athymic mice chronically treated with TAM reproducibly develop a TAM stimulated phenotype (Osborneet al., Eur J Cancer Clin Oncol 23: 1189-1196, 1987; Gottardis and Jordan, Cancer Res 48: 5183-5187, 1988; Osborneet al., J Natl Cancer Inst 83: 1477-1482, 1991; Wolfet al., J Natl Cancer Inst 85: 806-812, 1993). Tumors of this type may provide a useful model for a subset of therapeutic failures in the clinic. Therefore, we have extensively studied this model in an attempt to define the mechanism or mechanisms leading to TAM stimulated growth. In this paper we describe the characteristics of 4 TAM stimulated MCF-7 tumor variants. All of these tumors are growth stimulated by TAM, but vary in their response to estradiol (E2) treatment, and grow poorly in placebo treated hosts. All tumor variants express estrogen receptor (ER) RNA and protein, which at the RNA level appear to be down regulated by TAM, and to a greater extent by E2. All tumors also express epidermal growth factor receptor (EGFR) RNA, which is down regulated by TAM, and further down regulated by E2. However, among the tumor variants analyzed, ER and EGFR levels appear to be inversely related. Further, despite the expression of ER by all 4 TAM stimulated tumor variants, E2 induction of progesterone receptor expression is very weak or entirely absent.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 227-236 
    ISSN: 1573-7217
    Keywords: breast cancer ; epidermal growth factor receptor ; gene expression ; hormone-indepence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Overexpression of the EGF receptor in breast cancer correlates with poor prognosis and failure on endocrine therapy for both ER−/EGFR+ and ER+/EGFR+ tumors, suggesting a role for EGFR in the progression to hormone independence. The identification of specific DNase I hypersensitive site patterns for the EGFR gene in ER+ vs. ER− cells implicates regions of the EGFR first intron in up-regulation of EGFR, while estrogen regulation studies indicate the involvement of a repressor(s) in the maintenance of low levels of EGFR. Based on these findings, a multi-step model is proposed for the progression of breast cancer from a hormone-dependent, ER+/EGFR- phenotype to an aggressive, hormone-independent, ER−/EGFR+ stage.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 285-299 
    ISSN: 1573-7217
    Keywords: metabolism ; magnetic resonance spectroscopy ; phospholipid biosynthesis ; phosphorus-31 MRS ; proton MRS ; carbon-13 MRS ; hormonal effects ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The basis for the use of nuclear magnetic resonance (NMR) spectroscopy as a tool to study the metabolism of breast cancer cells is described. The differences between proton (1H), carbon (13C), and phosphorus (31P) NMR methods is explained, and the techniques of cell extracts, cell suspensions and perfusion methods for cells are detailed. In order to perfuse cells they are preferably trapped in a gel matrix, either in the form of a thread or a bead. The gel must have appropriate properties that enables efficient oxygenation and availability of nutrients and drugs. The metabolic effects of perfusion of breast cancer cells with nutrients, drugs, and hormones are reported, and the clinical relevance of these results and methods are outlined.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 25
    ISSN: 1573-7217
    Keywords: breast cancer ; prognosis ; growth fraction ; Ki-67 ; TLI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In situ determination of proliferative activity was performed on 184 consecutive primary invasive breast cancers. Methods used were monoclonal antibody Ki-67 in immunohistochemistry and thymidine labeling index. Tumor proliferation correlated between both methods (p = 0.0001). For thymidine labeling index and Ki-67, respectively, significant correlations existed with histologic tumour grade and steroid hormone receptors (Tumor grade: TLIp = 0.0001; Ki-67 p = 0.0001. ER-ICA: TLI = 0.0001; Ki-67 p = 0.014. PgR-ICA: TLIp = 0.0001; Ki-67 p = 0.0008). For thymidine labeling index a significant correlation was demonstrated for overall survival (p = 0.001) and recurrence free survival (p = 0.01). No statistical significance was observed for clinical outcome and Ki-67 (overall survival p = 0.18; recurrence free survival p = 0.1). None of the factors, TLI or Ki-67, was an independent prognostic factor as demonstrated by multivariate analysis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 29 (1994), S. 3-9 
    ISSN: 1573-7217
    Keywords: growth factors ; receptors ; tyrosine kinase ; breast cancer ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The type 1 family of growth factor receptors includes the EGFR, c-erbB2, c-erbB3, and c-erbB4. All four members of the family are expressed in breast cancer. The EGFR gene and more frequently the c-erbB2 gene are amplified in a proportion of cases. In addition to increased expression as a result of gene amplification, overexpression of perhaps all of the receptors also appears to occur, probably as a result of increased mRNA transcription. Overexpression may have prognostic value and may predict response to current therapies. Finally these GFR proteins represent targets for new types of chemotherapeutic agents.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 27
    ISSN: 1573-7217
    Keywords: epidermal growth factor receptor ; prognostic factor ; c-erbB-2 ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have conducted two series of studies, a biochemical study and an immunocytochemical study, to investigate the role of epidermal growth factor receptor (EGFR) expression in primary breast cancer patients. In the biochemical study, a consecutive 115 patients were included and EGFR was measured by a competitive binding assay with multipoint Scatchard analysis. In the immunocytochemical study comprising 126 patients, EGFR status was determined by immunostaining with anti-EGFR antibody EGFR1. Several agreements were found from these two studies. EGFR status was inversely correlated with estrogen receptor (ER) status. No significant correlation was found between EGFR status and tumor size, nodal metastases, or the expression of c-erbB-2 protein. Ki-67 immunoreactivity, a cellular proliferation marker, was enhanced in EGFR positive tumors over EGFR negative tumors, suggesting a linkage of EGFR expression to cellular proliferative activity. Post-operative follow up showed that relapse-free survival for EGFR positive patients was significantly worse than that for EGFR negative patients, particularly in node-positive patients. Multivariate analysis demonstrated a significance of EGFR status as an independent prognostic indicator in primary breast cancer. The group expressing EGFR and c-erbB-2 protein indicated a particularly high risk for relapse.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 28
    ISSN: 1573-7217
    Keywords: breast cancer ; endocrine therapy ; epidermal growth factor receptor ; estrogen receptor ; Ki67 ; c-erbB-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 106 previously untreated breast cancer patients have been immunohistochemically analysed for EGF-R, ER, Ki67, and c-erbB-2 product. All patients received assessable endocrine therapy following disease progression. Significant associations were observed between EGF-R and ER (inverse) and Ki67 (direct). No association was observed between EGF-R and the c-erbB-2 product. EGF-R expression was significantly associated with the loss of endocrine sensitivity in breast cancer. This was observed in both ER positive and negative disease. In ER positive breast cancers, EGF-R expression had no significant influence on the quality of tumour remissions. Further sub-classification of the ER/EGF-R data by Ki67 immunostaining showed that in ER+/EGF-R- disease, increasing proportions of Ki67 positive cells were associated with a decline in the numbers of women experiencing good quality tumour remissions. A similar trend was also observed in ER+/EGF-R+ tumours. The presence of c-erbB-2 protein product did not influence endocrine sensitivity in any of the ER/EGF-R sub-groups.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 29
    ISSN: 1573-7217
    Keywords: breast cancer ; dehydroepiandrosterone ; DHEA ; intracrinology ; prevention
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The concentration of serum dehydroepiandrosterone sulfate (DHEA-S) and DHEA decreases markedly during aging, and low circulating levels of DHEA have been associated with a higher incidence of breast cancer in women. Using 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma in the rat as model, we have studied the effect of increasing serum levels of DHEA released from Silastic implants on the incidence of these tumors in the rat. Treatment with increasing doses of DHEA leading to serum DHEA levels comparable to those observed in normal adult women (7.1 ± 0.6 nM and 17.5 ± 1.1 nM) caused a progressive inhibition of tumor development from 68% bearing tumors in control animals to 22% and 11%, respectively. The average tumor area per rat decreased from 2.81 cm2 in intact control animals to 0.96 and 0.09 cm2 in the groups treated with the same doses of DHEA, respectively. The present data indicate that circulating levels of DHEA similar to those found in normal adult premenopausal women exert a potent inhibitory effect on the development of DMBA-induced mammary tumors in the rat, thus suggesting the possibility of a new and more physiological approach for the prevention of breast cancer in women.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 1573-7217
    Keywords: breast cancer ; TGF-α ; TNF-α ; monoclonal antibody ; immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The function of different growth factors in the development and progression of malignant tumors and the role of cytotoxic cytokines in the host response generated against neoplasms have been recently studied. Anti-TGF-α and anti-TNF-α monoclonal antibody families have been developed and characterized previously by our laboratory. Libraries of anti-TGF-α and anti-TNF-α monoclonal antibodies were selected for equal immunoreactivity both in native (frozen) and in formaldehyde fixed, paraffin embedded histological sections. No differences were found between native and fixed samples demonstrated in 10 cases in the present prospective study. Retrospective investigation was performed in 35 histopathological specimens of breast cancer patients detailed clinically and observed during 5 years after the surgical treatment. Correlation between TGF-α and/or TNF-α expression and clinical staging - TNM score, lymph node metastasis, tumor recurrence and survival time - was analyzed. According to our present study, the TGF-α positive patients had worse clinical prognosis than the TNF-α positive and double positive cases during long term observation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 31
    ISSN: 1573-7217
    Keywords: breast cancer ; doxorubicin ; chemotherapy ; ifosfamide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ifosfamide has single agent activity in advanced breast cancer and may potentiate the activity of doxorubicin. The combination of ifosfamide 5 g/m2 and doxorubicin 40 mg/m2 every 3 weeks for 4 cycles was used to treat 77 patients with advanced breast cancer. Fifty three patients had not received prior chemotherapy. All patients had one or more poor prognostic features, including tumor expression of epidermal growth factor receptor in 11/12 tested. The overall response rate was 74% (95% confidence intervals 62%-83%). The median survival was 9.4 months. The principal toxicities were febrile neutropenia and ifosfamide encephalopathy each in 6% of patients. A high percentage of the projected dose intensity was administered. This is a highly active combination with acceptable toxicity in advanced breast cancer, although the long term survival remains poor. Further exploration of ifosfamide in combination chemotherapy for advanced breast cancer is warranted.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 32
    ISSN: 1573-7217
    Keywords: breast cancer ; ornithine decarboxylase ; polyamines ; estradiol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies have shown that natural polyamines - putrescine, spermidine, and spermine - play a key role in the mechanism of action of estrogens in breast cancer. Ornithine decarboxylase (ODC) is the first enzyme of the polyamine biosynthetic pathway. To examine estrogenic regulation of polyamine biosynthesis in breast cancer, we measured ODC mRNA, ODC activity, and polyamine levels in G1 synchronized MCF-7 cells. ODC mRNA and activity increased four-fold over that of cells in G1 phase between 8 to 16 h after the addition of estradiol. Polyamine levels showed a sharp increase by 8 h after the addition of estradiol and decreased by 12 h. We further examined whether synthetic homologs of putrescine or spermidine could replace natural polyamines in supporting MCF-7 cell growth. Treatment of MCF-7 cells with 1 mM difluoromethylornithine (DFMO), an inhibitor of ODC, suppressed putrescine, spermidine, and spermine levels by 74, 78, and 10%, respectively, within 48 h. Cells treated with DFMO for 48 h were supplemented with either putrescine or its homologs or spermidine or its homologs. Diaminopropane, diaminobutane (putrescine), and diaminopentane were capable of fully or partially reversing the growth inhibitory effects of DFMO, whereas diaminoethane had no significant effect. Among a series of triamines, H2N(CH2)nNH(CH2)3NH2 (where n = 2 to 8; abbreviated as APn n = 4 for spermidine, or AP4), spermidine was most effective in reversing the effects of DFMO, whereas compounds with shorter or longer methylene bridging regions were less effective. AP8 was ineffective in reversing the growth inhibitory effects of DFMO. At 10 µM concentration, AP8 also inhibited DNA synthesis by 66%, as measured by [3H]-thymidine incorporation. These data show that MCF-7 cells have a strong requirement for polyamines for their growth and that estradiol stimulates the polyamine cascade by inducing the ODC mRNA level. Our results also suggest that polyamine homologs such as AP8 might be potentially useful in breast cancer therapy.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 33
    ISSN: 1573-7217
    Keywords: aromatase inhibitor ; breast cancer ; growth factors ; hormonal treatment ; insulin-like growth factor I ; postmenopause
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A number of endocrine treatments for advanced breast cancer seem to affect serum insulin-like growth factor I (IGF-I). The aim of our study was to investigate IGF-I levels in 33 postmenopausal patients with metastatic disease receiving the selective aromatase inhibitor 4-hydroxyandrostenedione: 250 mg (16 patients) or 500 mg (17 patients) i.m. fortnightly. Blood samples were collected before, and at one month and 3 months after the beginning of treatment for radioimmunoassay determinations. The median patient age was 56 and 60 years in the 250 and 500 mg groups respectively. Most patients had a disease free interval ≥ 2 years and were oestrogen receptor positive. Objective responses were obtained in 3 patients (complete response, 1) in the 250 mg group, and in 7 patients (complete response, 3) in the 500 mg group. No significant IGF-I variations were seen in the 250 mg group, whereas a significant increase after 3 months (181.57 ± 84.78 ng/mlversus 272.47 ± 213.22 ng/ml, p = 0.0032) was observed in the 500 mg group. No IGF-I variations were seen between responsive and unresponsive patients in either treatment group. Our results in the 500 mg group are close to those obtained with aminoglutethimide and seem to agree with the hypothesis of an oestrogen-induced suppression of IGF-I circulating levels.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 34
    ISSN: 1573-7217
    Keywords: breast cancer ; immunity ; tumor antigen ; ferritin ; iron ; transferrin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fifty-two breast cancer patients were evaluated for levels of several molecules related to iron metabolism including determining their tumor tissue and serum ferritin levels, serum transferrin levels, and serum iron levels. In addition the patients' lymphocyte immunity against autologous tumor antigen was investigated. Forty percent (21 of 52) of the patients had lymphocyte immunity against tumor antigen. Iron metabolism molecules were expressed in abnormal quantities in some breast cancer patients: 27% (13 of 49) had elevated tumor tissue ferritin levels, 4% (2 of 49) had abnormally high serum ferritin, 10% (5 of 49) had abnormally low serum transferrin levels, and 43% (21 of 49) had depressed serum iron levels. None of these abnormalities in iron metabolism are associated with tumor immunity. These iron metabolism molecules may be indicative of rates of cell proliferation or may influence growth of breast cancer cells, but do not appear to influence host lymphocyte immunity against tumor associated antigens.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 325-335 
    ISSN: 1573-7217
    Keywords: breast cancer ; vimentin ; invasion ; integrins ; cadherins ; epithelial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Eighteen breast cancer cell lines were examined for expression of markers of epithelial and fibroblastic differentiation: E-cadherin, desmoplakins, ZO-1, vimentin, keratin and β1 and β4 integrins. The cell lines were distributed along a spectrum of differentiation from epithelial to fibroblastic phenotypes. The most well-differentiated, epithelioid cell lines contained proteins characteristic of desmosomal, adherens and tight junctions, were adherent to one another on plastic and in the basement membrane matrix Matrigel and were keratin-positive and vimentin-negative. These cell lines were all weakly invasive in anin vitro chemoinvasion assay. The most poorly-differentiated, fibroblastic cell lines were E-cadherin-, desmoplakin- and ZO-1-negative and formed branching structures in Matrigel. They were vimentin-positive, contained only low levels of keratins and were highly invasive in thein vitro chemoinvasion assay. Of all of the markers analyzed, vimentin expression correlated best within vitro invasive ability and fibroblastic differentiation. In a cell line with unstable expression of vimentin, T47DCO, the cells that were invasive were of the fibroblastic type. The differentiation markers described here may be useful for analysis of clinical specimens and could potentially provide a more precise measure of differentiation grade yielding more power for predicting prognosis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 39-47 
    ISSN: 1573-7217
    Keywords: breast cancer ; p53 gene ; p53 protein ; prognosis ; therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Alterations of the p53 tumor suppressor gene are the most common genetic changes found so far in breast cancer, suggesting that the gene plays a central role in the development of the disease. p53 functions as a negative regulator of cell growth, and alterations in the gene lead to loss of this negative growth regulation and more rapid cell proliferation. A number of independent groups using different methods of detection have shown that p53 alterations are associated with more aggressive tumor biologic factors and a poorer prognosis in breast cancer patients. Because of its possible role in the regulation of apoptosis and response to DNA damage, p53 status could also be a predictive marker for response to hormonal or chemotherapy.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 37
    ISSN: 1573-7217
    Keywords: antiestrogens ; breast cancer ; drug resistance ; flow cytometry ; tamoxifen ; toremifene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Flow cytometric analysis of DNA ploidy and S-phase fraction are well recognized prognostic indicators in breast cancer. The present paper deals with the widening of the applications of flow cytometry to monitoring the effectiveness of antiestrogen therapy, detecting clonal selection and emergence of drug resistance, and monitoring chemosensitizing properties of drugs. Antiestrogen activity can be studied by DNA flow cytometry to address clinical research problems such as patient-specific pharmacokinetics, dosing compliance, and acquired antiestrogen resistance. Patient plasma specimens containing various concentrations of triphenylethylenes can be monitored for drug-induced effects using cell cycle measurements and correlated toin vivo drug levels. DNA flow cytometry has also been instrumental in the study of the effects of prolonged low-dose (0.5 µM for 〉 100 days) tamoxifen treatment on human estrogen receptor negative MDA-MB-231 cells, where it was shown that tamoxifen may significantly alter cell cycle kinetics and tumorigenicity of these cells, selecting a new, more aggressive, and rapidly growing clone. Lastly, it has been shown that the chemosensitizing properties of another triphenylethylene antiestrogen, toremifene, on estrogen receptor negative, multidrug resistant MDA-MB-231-A1 human breast cancer cells can be studied using flow cytometric analysis. Toremifene (and its metabolites N-desmethyltoremifene and toremifene IV) are able to “resensitize” MDA-MB-231-A1 cells to vinblastine and doxorubicin, as reflected in a marked shift of cells to G2/M phase of the cell cycle. Flow cytometry is a widely available technique that might be applied clinically to monitor, at the cellular level, drug effects on tumors, including the modulators of drug resistance.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 73-84 
    ISSN: 1573-7217
    Keywords: bisphosphonates ; bone resorption ; breast cancer ; cadherins ; matrix metalloproteinases ; osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Metastasis of breast cancer cells to bone consists of multiple sequential steps. To accomplish the process of metastasis to bone, breast cancer cells are required to intrinsically possess or acquire the capacities that are necessary for them to proliferate, invade, migrate, survive, and ultimately arrest in bone. These capacities are essential for any cancer cells to develop distant metastases in organs such as lungs and liver as well as bone. Once breast cancer cells arrest in bone, bone is a storehouse of a variety of cytokines and growth factors and thus provides an extremely fertile environment for the cells to grow. However, breast cancer cells are unable to progress in bone unless they destroy bone with the assistance of bone-resorbing osteoclasts. Thus, the capacity of breast cancer cells to collaborate with osteoclasts is likely to be specific and is likely critical for them to cause osteolytic bone metastases. Evidence to support the concept that there is an intimate relationship between breast cancer cells and osteoclasts is described using anin vivo bone metastasis model in which human breast cancer cells are inoculated into the left ventricle of nude mice. The roles of cell adhesion molecules including cadherins and laminin and matrix metalloproteinases in the development of osteolytic bone metastases by breast cancer are also discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 97-103 
    ISSN: 1573-7217
    Keywords: breast cancer ; epidermal growth factor receptor ; immunotoxins ; ligand fusion toxins ; targeted therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Immunotoxins are a relatively new class of cytotoxic agents consisting of a catalytic toxin linked to an appropriate targeting ligand. The ligand directs the toxin to the surface of a tumor cell, whereupon the toxin enters the cell and catalytically inactivates the ribosome, thus disrupting protein synthesis and effecting cell death. Monoclonal antibodies (or their fragments) have been most commonly used to carry chemically conjugated toxins to proteins or antigens overexposed on the tumor cell surface, but specific ligands for tumor cell surface receptors could also provide effective targeting. The receptor for epidermal growth factor (EGFR) is overexpressed primarily in poor prognosis breast cancers that do not respond well to traditional therapies. Because EGFR is frequently overexpressed in breast cancer tissue and is associated with a poor prognosis, it is an attractive target for antitumor therapy. DAB 389 EGF is an EGFR specific fusion toxin produced with recombinant DNA techniques consisting of sequences for the enzymatically active and membrane translocation domains of diphtheria toxin plus sequences for human epidermal growth factor. DAB 389 EGF is a potent, EGFR specific, cytotoxic agent which rapidly inhibits protein synthesis by a mechanism of action similar to that of diphtheria itself. Preclinical studies in the laboratory and in animals now suggest the feasibility of investigating such an agent in the targeted therapy of patients with human breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 113-118 
    ISSN: 1573-7217
    Keywords: axillary nodal status ; breast cancer ; neural networks ; prognostic markers ; staging ; survival analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neural networks can be used as pattern recognition systems in complex data sets. We are exploring their utility in performing survival analysis to predict time to relapse or death. This technique has the potential to find easily some types of very complex interactions in data that would not be easily recognized by conventional statistical methods. In this paper we demonstrate that there are several ways neural networks can be used to find three-way interactions among variables. Thus, in data sets where such complex interactions exist, neural networks may find utility in detecting such interactions and in helping to produce predictive models.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 319-325 
    ISSN: 1573-7217
    Keywords: breast cancer ; computer modeling ; kinetics ; therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Since adjuvant chemotherapy and hormonal therapy generally extend disease free survival in breast cancer rather than provide a cure, we have examined the current breast cancer paradigm. Heterogeneity is a fundamental characteristic of breast cancer tissue and a well recognized aspect of the disease. There are variations in natural history, histopathology, biochemistry and endocrinology, and molecular biology of cancer tissues and cells within the tissues. A variety of data indicate that growth kinetics are also variable, not only from tumor to tumor, but also during the natural history of an individual's tumor. To better understand kinetic heterogeneity, a stochastic numeric computer model of the natural history of breast cancer has been developed. To be consistent with inter- and intratumor kinetic heterogeneity and with late relapse, the model predicts that tumors grow in an irregular fashion with alternating periods of growth and periods of dormancy rather than the generally accepted modified exponential, or Gompertzian fashion. The prediction of irregular growth has been compared to data relevant to growth characteristics of human breast cancer. Much data support the concept of irregular kinetics and temporary dormancy rather than steady, Gompertzian growth of human breast cancer. Thus, in addition to drug resistance, kinetic heterogeneity may help explain the limited impact that traditional chemotherapeutic treatment has had on mortality from breast cancer. Although the mechanisms underlying irregular growth need to be better understood, non-Gompertzian growth kinetics indicates that there may be alternative approaches for breast cancer treatment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 61-71 
    ISSN: 1573-7217
    Keywords: antiestrogens ; breast cancer ; endometrium ; growth factors ; IGFs ; TGFs ; tamoxifen ; uterine cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The basis of the anti-proliferative action of antiestrogens is generally considered to be their ability to inhibit estrogen induced growth pathways by competitively inhibiting the binding of estrogen to the estrogen receptor. Recent data suggest that this may not be the entire story. Moreover, the cascade of events responsible for inhibition of mitogenesis after an initial interaction with the estrogen receptor is poorly understood. Multiple growth factor pathways operate in both normal and neoplastic estrogen/antiestrogen target tissues. While it is unlikely that any single pathway is pivotal, interactions of estrogen and/or antiestrogens with some of these pathways have been implicated in their proliferative effects. The exact molecular mechanisms remain unclear but autocrine, paracrine/juxtacrine, intracrine, and endocrine mediators or various combinations of them are likely to be involvedin vivo. Super-imposed on this is the possibility that ‘cross-talk’ between intracellular signaling pathways may also be involved. Elucidation of such molecular mechanisms will be important with respect to design of novel antiestrogenic/antimitogenic drugs and alternative treatment strategies for both breast and uterine cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 1-4 
    ISSN: 1573-7217
    Keywords: breast cancer ; drug resistance ; growth factors ; heat shock proteins ; imaging ; premalignant disease ; prognostic factors ; tumor suppressor genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 44
    ISSN: 1573-7217
    Keywords: breast cancer ; epidermal growth factor receptor ; immunocytochemistry ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Epidermal growth factor receptor (EGFR) is a potentially useful new biological prognostic and predictive indicator in human breast cancer. Additional research on EGFR is warranted to enhance our information on: i) the method of choice for its detection and quality control issues; ii) its association with novel pathobiological markers of prognosis; iii) its prognostic value in multivariate analysis; and iv) its capability to predict response to hormone therapy and, in the future, to biological treatments using antibodies against the specific receptor or its ligands. In the present study we update previous data on EGFR status, determined immunocytochemically, by prolonging the period of observation up to 5 years and by including, in the multivariate analysis, several new biological indicators. The main results obtained are: i) EGFR is weakly associated with Ki-67 score (p=0.073) and with p53 expression (p=0.06); ii) EGFR is a significant indicator for recurrence (p〈0.01 and odds ratio of 2.82) but not for death (p=0.27 and odds ratio of 1.49); iii) the prognostic power of EGFR is enhanced when combined with the knowledge of S-phase fraction; and iv) in multivariate analysis on relapse-free survival, EGFR and S-phase fraction (likelihood ratio test=26.40; p〈0.01), c-erbB-2 protein and p53 mutant protein expression (likelihood ratio test= 5.94; p=0.05), cathepsin D (likelihood ratio test= 9.78; p〈0.01), and nodal status (likelihood ratio test= 7.32; p〈0.01) are significant and independent prognostic factors in early-stage breast carcinoma. This new information could be of help for a more rational approach in the use of EGFR as a marker in future clinical research.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 45
    ISSN: 1573-7217
    Keywords: breast cancer ; CAM 5.2 antibody ; cytokeratin ; flow cytometry ; prognosis ; S-phase fraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Estimation of S-phase fraction in breast carcinomas with single parameter flow cytometry may include errors due to dilution of cancer cells by host cells. Use of tissue specific markers may to some extent correct for the effect of dilution. S-phase fraction was estimated by flow cytometry with and without immunoselection in 80 DNA-euploid breast carcinomas in stage I-II. The tumor tissue was mechanically disintegrated and fixed in ethanol. A primary antibody, specific for cytokeratins 8 and 18, was added before incubation with the secondary FITC-conjugated antibody. S-phase fraction was calculated for both the gated (cytokeratin-positive) and the ungated cell population. An increasing proportion of tetraploid cells compared to diploid cells was found when the immunoselection method was used. The gated population tended to have a higher S-phase fraction than the ungated population. In univariate analysis S-phase fraction estimated from both ungated and gated cell populations yielded significant information for predicting recurrence when stratified for tumor size and nodal status. In bivariate analysis S-phase fraction of the gated population contributed prognostic information in addition to S-phase fraction of the ungated population when both variables were included in the analysis. Our conclusion is that S-phase fraction calculated from cytokeratin-positive cells provides prognostic information in addition to ungated S-phase values in DNA euploid breast carcinomas.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 46
    ISSN: 1573-7217
    Keywords: epidermal growth factor receptor ; breast cancer ; prognostic factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prognostic value of epidermal growth factor receptor (EGF-R) was prospectively assessed in a series of 229 clinical T1-T2, N0-N1 breast carcinomas diagnosed between May 1987 and October 1989. EGF-R expression was determined by measuring the specific Bmax of125I EGF to tumor plasma membrane preparations. Tumor with a B max ≥ 3 fmol/mg of protein were considered positive with regard to EGF-R expression. With a median follow-up of 34 months, the 3-year overall and disease-free survivals are respectively 92% and 88% for EGF-R ≤ 3, and 91% and 86% EGF-R 〉 3 fmol, showing no significant difference, even when comparing axillary lymph node status. We did not succeed in finding an EGF-R cut-off value which might be significant in univariate analysis. Multivariate analysis of our data indicates that pT (p = 0.001), pN (p = 0.04), and Scarff-Bloom grade (p = 0.04) are the only significant predictors of disease-free survival among the parameters investigated in this study.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 30 (1994), S. 81-87 
    ISSN: 1573-7217
    Keywords: 4-hydroxyandrostenedione ; aromatase ; aromatase inhibitor ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 4-hydroxyandrostenedione is a steroidal, suicide substrate inhibitor of aromatase, which has been widely tested in postmenopausal breast cancer patients. It is highly specific with the only notable endocrine changes other than oestrogen suppression being a dose-related suppression of sex-hormone binding globulin when the drug is given orally (a reflection of the drug's minor androgenic activity). Intramuscular administration of 250 mg every second week is the schedule of choice. This achieves peripheral aromatase inhibition of about 85% and oestradiol suppression of about 65%. The drug is usually used second-line, after tamoxifen, with an overall response rate in unselected patients of 26%. Side-effects are minimal and consist almost entirely of local reactions at the site of injection. 4-hydroxyandrostenedione is therefore a useful new treatment option as the first selective aromatase inhibitor to have wide clinical availability.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 30 (1994), S. 95-102 
    ISSN: 1573-7217
    Keywords: breast cancer ; aromatase inhibitors ; CGS 20267 ; CGS 16949A ; hormone ablative therapy ; breast cancer treatment ; endocrine therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fadrozole Hydrochloride (CGS 16949A) and Letrozole (CGS 20267), are two of the newest non-steroidal, orally active aromatase inhibitors currently being evaluated as second line treatment of patients with hormone dependent forms of metastatic breast cancer. In a phase I clinical efficacy study, we examined the ability of these two imidazole derivatives to suppress the synthesis of estrogen in a cohort of postmenopausal patients with metastatic breast cancer. Both medications at relatively low doses were potent and rapid inhibitors of aromatase activity as evidenced by their ability to suppress the level of blood and urine estradiol and estrone as well as blood estrone sulfate in these patients. Letrozole appeared to be the more potent of the two, with over 95% suppression of both plasma and urinary estrogens observed within 2 weeks of therapy. Letrozole appeared to be more selective than Fadrozole in inhibiting aromatase activity in that no compromise in cortisol and aldosterone output was evident with Letrozole therapy at all of the doses tested, a compromise clearly seen with Fadrozole. The inhibition of aromatase activity by these imidazole derivatives as second line therapy for patients with hormone dependent breast cancer appears to be a favorable alternative form of hormone ablative therapy and holds considerable promise for the treatment of this malignancy.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 49
    ISSN: 1573-7217
    Keywords: malignant progression ; estrogen ; carcinogenesis ; hormone dependence ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have established and characterized a series of variant cell lines in which to identify the critical factors associated with E2-induced malignant progression, and the acquisition to tamoxifen resistance in human breast cancer. Sublines of the hormone-dependent MCF-7 cell line (MCF7/MIII and MCF7/LCC1) form stable, invasive, estrogen independent tumors in the mammary fat pads of ovariectomized athymic nude mice. These cells retain expression of both estrogen (ER) and progesterone receptors (PGR), but retain sensitivity to each of the major structural classes of antiestrogens. The tamoxifen-resistant MCF7/LCC2 cells retain sensitivity to the inhibitory effects of the steroidal antiestrogen ICI 182780. By comparing the parental hormone-dependent and variant hormone-independent cells, we have demonstrated an altered expression of some estrogen regulated genes (PGR, pS2, cathepsin D) in the hormone-independent variants. Other genes remain normally estrogen regulated (ER, laminin receptor, EGF-receptor). These data strongly implicate the altered regulation of a specific subset or network of estrogen regulated genes in the malignant progression of human breast cancer. Some of the primary response genes in this network may exhibit dose-response and induction kinetics similar to pS2, which is constitutively upregulated in the MCF7/MIII, MCF7/LCC1 and MCF7/LCC2 cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 50
    ISSN: 1573-7217
    Keywords: stromal epithelial interactions ; insuline-like growth factors ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The prominent ‘desmoplastic’ or stromal reaction seen in many invasive breast carcinomas lead to early speculation that stromal cells play a role in breast cancer pathogenesis [1]. Experimental evidence now supports this hypothesis and interactions between stromal cells and epithelial cells appear to be important for both normal mammary development and neoplasia. The identification of genes that are selectively expressed in the stroma of malignant breast lesions has recently provided new insights into the molecular basis of stromal-epithelial interactions. Stromally expressed genes include growth factors, proteases and extracellular matrix proteins, all biological activities with potential roles in malignant progression. Investigations discussed here concern the nature of the paracrine signals provided by malignant epithelial cells that activate changes in stromal gene expression, the effect that the stromally derived factors have on the behavior of malignant epithelial cells and the identification of novel factors and receptors in either stroma or epithelia that contribute to their mutual interactions. These questions will be addressed in the context of this laboratory's studies on insulin-like growth factors, as these molecules show marked differences in stromal expression between benign and malignant breast tissue and thus provide a useful paradigm for investigations into the paracrine environment of an evolving breast tumor.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 51
    ISSN: 1573-7217
    Keywords: breast cancer ; oncogenes ; p53 transformation ; temperature sensitive mutant ; tumor suppressors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary One common step in the malignant progression of a wide variety of human cancers seems to be inactivation of the p53 gene, via point mutation or deletion or both; or overexpression of mutated protein with dominant transforming activity. This study shows a suppressive effect of wild type p53 on the growth of human breast cancer cells. Introduction of wild type p53 versus mutant into five human breast cancer cell lines containing mutant p53 resulted in a marked reduction in colony formation. Two of these were transfected with human wt p53 expression vectors and the other three were infected with retroviruses packaging human wt p53, both showing similar reduction in the number of surviving colonies, suggesting a role for wt p53 in suppression of breast cancer cell growth. Direct evidence for growth suppression was obtained by introduction of the temperature sensitive p53Val135 into Hs578T human breast cancer cells containing a mutant p53. This murine mutant allele p53Val135 functions as an oncogene at 37° C and as a tumor suppressor at 32° C. The cell line generated was strongly growth inhibited at the restrictive temperature (31.5° C), at which temperature the suppressor form is expressed. This inhibition of proliferation was reversible upon a temperature upshift. Analysis of the cell cycle distribution shows these growth suppressed cells to be inhibited in the G1 phase of the cell cycle. Thus wt p53 may have an important role in breast cancer tumorigenesis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 30 (1994), S. 197-200 
    ISSN: 1573-7217
    Keywords: breast cancer ; CA 15-3 ; IAP ; immunosuppressive acidic protein ; tumor markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Immunosuppressive acidic protein (IAP) has been described as a tumor marker in a number of malignant diseases. To evaluate the clinical importance of IAP in breast cancer patients, IAP serum level was determined in 75 breast cancer patients, using single radial immunodiffusion. Serum samples were also tested for CA 15-3. Cut off value for IAP was determined according to IAP serum level in 50 patients with benign, non inflammatory, diseases, and was set as 725 microgram/ml. Mean IAP serum level (623 mcg/ml) and positivity rate (20%) in 24 breast cancer patients with active disease were similar to those in 51 breast cancer patients with no evidence of disease (590 mcg/ml and 18%). The mean CA 15-3 serum level and positivity rate were significantly higher in patients with active disease (200 units/ml, 67%), compared to patients with no evidence of disease (18.3 units/ml, 6%). In our experience IAP was not found to be an effective tumor marker in breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 30 (1994), S. 201-204 
    ISSN: 1573-7217
    Keywords: breast cancer ; hepatocellular carcinoma ; tamoxifen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary It has been hypothesized that hepatocellular carcinoma might be a long-term adverse effect of tamoxifen therapy. Data from nine population-based cancer registries in the United States were used to investigate time trends in the incidence of hepatocellular carcinoma in white women previously diagnosed with invasive breast cancer during 1974–1987 and followed until 1989. Of particular interest were the rates after 1977, the year tamoxifen was licensed by the FDA. Compared to rates in all white women, no increased risk of hepatocellular carcinoma was found in women most likely to have received tamoxifen - those 50 years of age or more at diagnosis of breast cancer and diagnosed after 1977. These results suggest that tamoxifen does not cause a large increase in the incidence of hepatocellular carcinoma within the first decade after use. However, smaller and/or later increases in the risk for hepatocellular carcinoma are possible and warrant continued monitoring of women treated with tamoxifen.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 54
    ISSN: 1573-7217
    Keywords: breast cancer ; folinic acid ; 5FU ; metastatic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Standard combination chemotherapy for metastatic breast cancer produces response rates between 30–60% with limited impact on survival. We undertook a phase II trial to determine the activity of 5 fluorouracil (5FU) and folinic acid (FA) in patients with measurable metastatic or recurrent breast cancer who had received no prior chemotherapy. Patients meeting the eligibility criteria received 5FU 370 mg/m2/day and FA 200 mg/m2/day for 5 days repeated every 28 days, toxicity allowing. Response defined by standard criteria was assessed every 8 weeks and toxicity according to WHO criteria was determined on every course. Thirty-three patients were entered on trial. Thirty-two patients were evaluable for response and 33 for toxicity. The dose limiting toxicity was stomatitis with 7/32, 19/32, and 5/32 patients experiencing grade 1, 2, and 3 toxicity. Grades 1 and 2 diarrhea occurred in 17/32 and 11/32 patients respectively. Myelosuppression was not significant. Two complete and 11 partial responses were observed. The overall response rate was 41% (95% CI, 24–58%). Responses were seen in soft tissue and visceral sites. Patients who had received adjuvant chemotherapy more than 6 months prior to receiving 5FU and FA responded also. Six of 29 patients receiving standard combination chemotherapy as second line treatment responded subsequently. We concluded: 1) 5FU and FA is an active combination in the treatment of breast cancer warranting further evaluation in combination with other drugs; 2) the dose-limiting toxicity of stomatitis is tolerable; 3) patients receiving 5FU and FA as first line therapy can respond to conventional combination chemotherapy as second line treatment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 55
    ISSN: 1573-7217
    Keywords: breast cancer ; monoclonal antibodies ; mucins ; multivariate analysis ; prognosis ; relapse ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Monoclonal antibody (MoAb) BrE-3, an anti-human milk fat globule (HMFG) MoAb, is used here as a novel prognostic indicator for survival and relapse time in patients with infiltrating ductal carcinoma of the breast. A scoring system (4-Score method) was developed to this effect that measured, in a statistically reliable fashion, the level of expression of the epitope for MoAb BrE-3 in the cytoplasm and membranes of breast carcinoma cells in paraffin-embedded sections. In univariate analysis, data obtained by the 4-Score Method as well as data from traditional prognostic indicators (tumor size, axillary node status, and grade of differentiation) were found to be associated with patient survival and relapse. In multivariate analysis, using a Cox proportional hazards regression model, levels of expression of BrE-3 epitope plus tumor size and axillary node status were weighted and combined in an Individual Linear Composite Prognostic Score (ILCPS) that had a high level of association with survival and relapse time in this sample model of patients with infiltrating ductal carcinoma of the breast. This level of association was found to be higher than the level of association for any other combination of traditional or 4-Score method variables. The level of expression of BrE-3 significantly adds to the prognostic capacity of traditional prognostic markers for infiltrating ductal carcinoma of the breast.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 30 (1994), S. 283-292 
    ISSN: 1573-7217
    Keywords: breast cancer ; oral contraceptives ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 471 breast cancer patients the influence of a positive history of oral contraceptive (OC) use on survival was investigated. 297 (63%) patients used OCs during any period of their life and 92 (20%) used them still at the time of diagnosis. Sixty months after diagnosis OC users had a significantly increased overall survival (p = 0.037). Survival rates amounted to 79.5% and 70.3% for OC users and non-users, respectively. The effect persisted after adjustment for other prognostic factors and was mainly attributed to women who had taken OCs four years or longer (p = 0.025). Comparing the survival after a 56 months median follow-up dependent on duration of OC use (never, 1–48 months, ≥ 49 months) in subgroups of prognostic factors, the most significant influence on survival was observed among long-term users with tumors more than 2 cm in diameter (p = 0.005), with axillary node-positive tumors (1–3 nodes, p = 0.055/≥ 4 nodes, p = 0.019), and with tumors of low estrogen receptor (p = 0.015) or progesterone receptor content (p = 0.04). The difference in survival between OC users and non-users cannot be explained by the distribution of prognostic factors investigated (histological type, histological grade, tumor size, lymph node involvement, hormonal receptor content). OC users had an even higher percentage of poorly differentiated tumors (p = 0.003). These results suggest an effect of OC use on tumor biology during the preclinical phase of the disease.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 27-39 
    ISSN: 1573-7217
    Keywords: antiestrogen ; breast cancer ; endometrial carcinoma ; endometrium ; tamoxifen ; uterus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Since its introduction in the early seventies, the list of indications for the use of the antiestrogen tamoxifen has been continuously expanded. Tamoxifen is now used for the treatment of metastatic breast cancer and for long-term and often indefinite administration as an adjuvant therapy. Large clinical trials in three countries are now evaluating the efficacy of tamoxifen as a preventive agent. However, tamoxifen therapy has been associated with an increased incidence of endometrial carcinoma. Laboratory and clinical data available to date on this controversial issue can be summarized as follows: a) Tamoxifen can have an estrogenic effect on endometrium in the presence of low estrogen levels. b) Tamoxifen treatment is probably associated with an increased incidence of endometrial cancer; however, this association appears to be linked to higher tamoxifen doses (40mg/d). d) It is not known whether tamoxifen causes or allows the identification of occult endometrial carcinoma. e) At the present time there is evidence for a tumor promoting effect of tamoxifen on endometrial cancer at a dose of 20 mg per day. f) Replacement of tamoxifen by ‘pure’ antiestrogens or coadministration of progestins with tamoxifen do not appear to offer benefit unless clinical trials demonstrate a reduced incidence of endometrial problems. g) Patientsmust be evaluated for pre-exsisting endometrical carcinoma before starting tamoxifen therapy. f) Close followup of long-term tamoxifen patients with endometrial biopsies is recommended with individuals who experience symptoms.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 58
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 41-52 
    ISSN: 1573-7217
    Keywords: tamoxifen ; pure antiestrogens ; breast cancer ; prevention ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The success of antiestrogen therapy to treat all stages of breast cancer, and the evaluation of tamoxifen as a preventive for breast cancer in normal women, have focused attention on the molecular mechanisms of antiestrogen action and mechanisms of drug resistance. The overall goal of research is to enhance current therapies and to develop new approaches for breast cancer treatment and prevention. Recent studies show that tamoxifen and the new pure antiestrogens appear to have different mechanisms of action: tamoxifen and related compounds cause a change in the folding of the steroid binding domain that prevents gene activation whereas the pure antiestrogens cause a reduced interaction at response elements and cause a rapid loss of receptor complexes. Tamoxifen treatment produces changes in the cellular and circulating levels of growth factors that could influence both receptor negative or receptor positive tumor growth and the metastatic potential of a tumor. These events may explain the survival advantage observed with tamoxifen therapy. However, the current therapeutic challenge is to avoid drug resistance during long-term tamoxifen therapy. Numerous explanations for drug resistance to tamoxifen have been suggested, including elevated estrogen levels, increased tumor antiestrogen binding sites, receptor mutations, and impaired signal transduction. However, it is probable that multiple mechanisms evolve to facilitate tumor survival. Most importantly, current research is examining mechanisms responsible for the beneficial actions of tamoxifen on bones and lipids as well as the potentially deleterious effects of tamoxifen on liver and endometrial carcinogenesis and retinopathy. The urgent need to understand antiestrogenic drug mechanisms and toxicity is being facilitated by the application of the technology developed for basic molecular biology.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 263-271 
    ISSN: 1573-7217
    Keywords: MDR1 ; Sp1 ; p53 ; PKA ; 8-Cl-cAMP ; breast cancer ; multidrug resistance ; transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The development of cross-resistance to many natural product anticancer drugs, termed multidrug resistance (MDR), is one of the major reasons why cancer chemotherapy ultimately fails. This type of MDR is often associated with over-expression of theMDR1 gene product, P-glycoprotein (Pgp), a multifunctional drug transporter. The expression of MDR in breast tumors is related to their origination from a tissue that constitutively expresses Pgp as well as to the development of resistance during successive courses of chemotherapy. Therefore, understanding the mechanisms that regulate the transcriptional activation ofMDR1 may afford a means of reducing or eliminating MDR. We have found thatMDR1 expression can be modulated by type I cAMP-dependent protein kinase (PKA), opening up the possibility of modulating MDR by selectively down-regulating the activity of PKA-dependent transcription factors which upregulateMDR1 expression. High levels of type I PKA occurs in primary breast carcinomas and patients exhibiting this phenotype show decreased survival. The selective type I cAMP-dependent protein kinase (PKA) inhibitors, 8-Cl-cAMP and Rp8-Cl-cAMP[S] may be particularly useful for downregulating PKA-dependent MDR-associated transcription factors, and we have found these compounds to downregulate transient expression of a reporter gene under the control of severalMDR1 promoter elements. Thus, investigations of this nature should not only lead to a greater understanding of the mechanisms governing the expression of MDR, but also provide a focus for pharmacologic intervention by a new class of inhibitors.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 301-307 
    ISSN: 1573-7217
    Keywords: breast cancer ; tamoxifen ; estrogen receptor ; antiestrogen resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Acquisition of the antiestrogen resistance by breast cancer cellsin vivo may result from a variety of mechanisms. The main pathway appears to involve loss of estrogen receptor (ER) expression or selection for ER negative cells among heterogenous population of tumor cells. However, clinical data suggest that, in about 30% of the cases, antiestrogen resistance arises even in the presence of estrogen receptors. Postulated mechanisms leading to the latter phenotype include selection for variant receptor forms during treatment, development of novel metabolic pathways for the drug, loss of nuclear co-factors, or activation of signal transduction pathway that cross activate ER signals. We have used anin vitro experimental system utilizing LY-2 cell line, an ER positive and antiestrogen resistant MCF-7 cell variant, to study the mechanism of antiestrogen resistance in the presence of functional ER. Result from a complementation experiment suggests that LY-2 phenotype is a recessive trait. Cloning of the genetic defect in the LY-2 cells would provide further insight for the mechanism of antiestrogen resistance in ER positive breast cancer cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 229-233 
    ISSN: 1573-7217
    Keywords: platelet derived growth factor ; PDGF ; breast cancer ; immunohistochemistry ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies suggest a prognostic role for PDGF in patients with breast cancer, with patients with high plasma PDGF levels or positive response to therapy. We have examined a further 58 patients with advanced breast cancer for the presence of tissue PDGF immunostaining. Patients displaying positive tissue immunostaining for PDGF had a highly significant shorter survival (p = 0.002) than patients with no immunostaining. In addition PDGF positive patients treated with combination chemotherapy had a significantly lower response rate (p = 0.05) than PDGF negative patients. These results confirm our previous findings that PDGF may be an important indicator of shortened survival and treatment failure in patients with advanced breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 301-310 
    ISSN: 1573-7217
    Keywords: breast cancer ; prognostic markers ; prostate specific antigen ; steroid hormone receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Prostate-specific antigen (PSA) is a glycoprotein produced by the epithelial cells of the prostate. PSA is currently used in clinical practice to facilitate diagnosis and monitoring of prostate carcinoma. The prostate is an organ that possesses androgen, estrogen, and progesterone receptors, and in this respect is similar to the breast. We postulated that breast tumors might also have the ability to produce PSA. We performed these studies on a collection of 525 tumor specimens collected for routine biochemical determination of estrogen and progesterone receptors. Using a highly sensitive immunofluorometric procedure, we measured the p53 tumor suppressor gene product and PSA. Twenty nine percent of the breast tumor extracts contained detectable levels of PSA immunoreactivity (〉 0.05 µg/L). The immunoreactive PSA content was associated with estrogen and/or progesterone receptor-positive tumors (P 〈 0.002). No association was found between PSA immunoreactivity and levels of the p53 tumor suppressor gene product (P = 0.37). High performance liquid chromatography and Western blot analysis revealed that the PSA immunoreactivity in the tumor had a molecular weight of 30 kDa, similar to that of seminal PSA. Immunoreactive PSA-positive tumors were associated with younger women (P = 0.012) and earlier disease stage (P = 0.064). We postulate that PSA immunoreactivity may be an additional marker of steroid hormone receptor-ligand action.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 63
    ISSN: 1573-7217
    Keywords: breast cancer ; lymphocyte populations ; phagocytosis ; natural killer (NK) activity ; tamoxifen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The number of leukocytes, proportion and absolute number of granulocytes, lymphocytes, CD4+ cells, CD8+ cells, CD16+ cells, B-lymphocytes, monocytes, natural killer cell (NK) activity, and granulocyte and monocyte phagocytic functions - ingestion and intracellular killing - were determined in a group of 27 patients with ductal invasive breast carcinoma, stage I-III, before and 7 months following postsurgical telecobalt radiotherapy, divided into two subgroups, one of them receiving tamoxifen (TMX group) and the other one not receiving any further therapy (control group). In control group, proportion of all lymphocytes and CD8+ cells as well as absolute number of all lymphocytes, CD4+, CD8+, CD16+ and B lymphocytes were decreased following TCT in comparison to their pre-TCT values, while in TMX group only absolute number of all lymphocytes remained decreased following TCT. Moreover, post-TCT proportions of all and CD8+ lymphocytes as well as absolute numbers of all and CD4+ and CD8+ lymphocytes in TMX patients were significantly increased in comparison to the same parameters in control post-TCT patients, although there was no difference between the two subgroups before TCT. At the other hand, granulocyte ingestion was decreased in post-TCT TMX patients compared to post-TCT values in control patients and NK cell activity showed a similar, although statistically not significant, tendency. It seems that TMX helps recovery of lymphocyte populations decreased by radiotherapy, probably by stimulation of cells carrying estrogen receptors, but its effects on phagocytic functions and probably NK cell activity seemed to be rather inhibitory than stimulatory.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 64
    ISSN: 1573-7217
    Keywords: breast cancer ; DNA ploidy ; flow cytometry ; medullary carcinoma of the breast ; S-phase fraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a population of 110 primary breast cancers with medullary features, registered in the Danish Breast Cancer Cooperative Group (DBCG) from 1977-82, we have determined ploidy and S-phase fraction (SF) by flow cytometry (FCM) on paraffin embedded tumour tissue. The distribution of DNA ploidy is not different from the distribution described for breast cancers in general. No difference is found between the subgroups of medullary and non-medullary cancer when using a new simplified histopathological definition of medullary carcinoma of the breast, recently proposed by us. When using the definition proposed by Ridolfiet al. in 1977, we find significantly more tumours with aneuploidy and high SF in the groups of typical medullary carcinoma (TMC) and atypical medullary carcinoma (AMC) than in the small group of non-medullary carcinoma (NMC), which seems a paradox, as patients with NMC have the worst prognosis. However, the number of patients in the NMC group is very small, and the percentage of aneuploid tumours is very low. In 84 protocolled patients we found no statistically prognostic importance of ploidy or SF, either in the whole group assessed or when stratifying for the histopathological subgroups. However, a prognostic influence of SF can be traced for the non-medullary cancers, according to the new definition, but not for the medullary cancers of the breast. The result emphasizes the impression of MC as being biologically different from other histological types of breast cancer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 65
    ISSN: 1573-7217
    Keywords: breast cancer ; epidemiology ; interval cancer ; screening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Risk factors for breast cancer were compared in 107 women with interval breast cancer (cancers occurring within 2 years after a negative screen) and 258 women with breast cancer detected at 1st screening. All women (aged 40–67) were screened in the DOM project (the Utrecht programme for the early detection of breast cancer). Women with an interval cancer reported more often a history of benign breast disease (OR 4.66, 95% C.I. 2.08-10.41) and an artificial menopause (OR 4.07; 95% C.I. 1.74-9.55) than women with a screen detected cancer. Women with an interval cancer were taller than women with a screen detected cancer; this was seen most clearly in women with an artificial menopause (X 2 for trend = 5.88; p = 0.02) and to a lesser extent in premenopausal women (X 2 for trend = 1.70; p = 0.19). Premenopausal women with an interval cancer were heavier than women with a screen detected cancer (X 2 for trend = 4.66; p = 0.03); whereas natural postmenopausal women with an interval cancer were leaner than women with a screen detected cancer (X 2 for trend = 1.57; p = 0.21). All analyses were done while correcting for age and selected other risk factors for breast cancer. These results suggest that the epidemiological profile of pre- and post-menopausal women with an interval cancer differs from that of women with a screen detected cancer, which might imply a different natural history of these two types of breast tumours.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 66
    ISSN: 1573-7217
    Keywords: aspiration ; breast cancer ; biomarkers ; prediction ; risk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Breast tissue biomarkers which accurately predict breast cancer development within a 10 year period in high risk women are needed but currently not available. We initiated this study to determine 1) the prevalence of one or more breast tissue abnormalities in a group of women at high risk for breast cancer, and 2) if the prevalence of biomarker abnormalities is greater in high risk than in low risk women. Eligible high risk women were those with a first degree relative with breast cancer, prior breast cancer, or precancerous mastopathy. Low risk women were those without these or other major identifiable risk factors. Ductal cells were obtained via random fine needle aspirations and cytologically classified. Biomarkers included DNA ploidy, estrogen receptor (ER), and epidermal growth factor receptor (EGFR). The prevalence of DNA aneuploidy was 30%, overexpression of ER 10%, and overexpression of EGFR 35%, in the 206 high risk women whose median 10 year Gail risk (projected probability) of developing breast cancer was 4.5%. The prevalence of aneuploidy and overexpressed EGFR was significantly higher in the high risk women than in the 25 low risk controls (p 〈 0.002), whose median 10 year Gail risk was 0.7%. The difference in the prevalence of ER overexpression between high and low risk groups was not statistically significant (p = 0.095). This may be due to the low prevalence of overexpressed ER and the small number of controls. A significant difference was noted in the prevalence of one or more abnormal biomarkers between the high risk and low risk women (p 〈 0.001). A large prospective trial is needed to determine if one or more of these biomarkers, is predictive of breast cancer development.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 67
    ISSN: 1573-7217
    Keywords: hsp27 ; gene regulation ; breast cancer ; heat shock transcription factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We present evidence that the mechanisms controlling induction of heat shock transcription factors (HSFs) and mRNA expression of the 27,000 molecular weight heat shock protein, hsp27, are diverse in human breast cancer cells. Heat shock accumulation of hsp27 RNA is associated with the activation of HSF in MDA-MB-231 cells. We have later passage MCF-7 breast cancer cell lines with elevated, constitutive expression of hsp27 mRNA, perhaps due to hsp 27 gene amplification. Estradiol and heat shock treatment no longer affect the level of hsp27 mRNA in these cells. Heat induction of HSF is inhibited in cells overexpressing hsp27, although metal ions and amino acid analogs are still capable of activating HSF. These cells will provide a useful system for characterizing alternative pathways in HSF inhibition and activation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 68
    ISSN: 1573-7217
    Keywords: breast cancer ; androgens ; menopausal status ; oestrogen receptor ; progesterone receptor ; age ; survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relationships between urinary 11-desoxy-17-oxo steroids (11-DOS), the ratio of 11-DOS to urinary 17-hydroxycorticosteroids (urinary discriminant ratio), plasma levels of the adrenal androgens dehydroepiandrosterone (DHA), DHA sulphate (DHAS), and 7α-hydroxy DHA (7αDHA), and tumour oestrogen receptor (ER) and progesterone receptor (PR) status were examined in pre, peri-, and postmenopausal women with breast cancer. Androgenic steroids and their metabolites decreased with age in women with breast cancer. In perimenopausal women there was a significant association of PR positive tumours and high androgen levels, whereas in postmenopausal women high androgen levels were associated with ER negative tumours. Survival was significantly related to plasma DHA level and tumour steroid receptor status. Thus, adrenal androgen levels below the group mean were associated with significantly decreased survival in women with postmenopausal receptor-positive tumours, and the association was particularly apparent in those who were axillary node negative. Since the number of patients studied was small these results should be regarded as provisional in nature. Nonetheless, the identification of this subgroup of node negative breast cancer women with reduced survival may be important when considering node negative patients for adjuvant therapy.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 32 (1994), S. 239-260 
    ISSN: 1573-7217
    Keywords: adhesion molecule ; breast cancer ; malignant disease ; metastasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 70
    ISSN: 1573-7217
    Keywords: breast cancer ; estrogen and progesterone receptors ; Ki67 antigen ; p53 protein ; fine-needle aspiration cytology ; immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fine-needle aspiration cytology has been already established as a reliable method for the diagnosis of breast cancer. Its application has been recently extended to immunocytochemical analysis of biological parameters. In the current study estrogen and progesterone receptors, Ki67 growth fraction, and p53 protein expression were immunocytochemically evaluated on the cellular material sampled by the same fine-needle aspirate used for the conventional cytologic diagnosis of malignancy. Fine-needle aspiration specimens from 100 patients with primary breast carcinoma were submitted to the immunocytochemical analysis. Twenty-eight percent were in premenopause; 23% had tumors with a diameter less than 2 cm, 59% from 2 to 5 cm, and 18% more than 5 cm; 60% had axillary nodal status negative, 34% positive, and 6% unknown. The concomitant immunocytochemical evaluation of all parameters was possible in 70% of the patients. A significant association was found between p53 overexpression and Ki67 values (p = 0.004), and between Ki67 values and progesterone receptor status (p = 0.003). No correlation was found between any parameter and clinical tumor size. Estrogen (p = 0.02) and progesterone (p = 0.04) receptor negativity and high Ki67 growth fraction (p = 0.005) were significantly associated with the clinical evidence of axillary node involvement. This study suggests that fine-needle aspiration cytology represents an effective practice for a simultaneous evaluation of multiple biologic indicators and could be useful as a preoperative procedure in patients who are candidates for neoadjuvant chemotherapy and/or endocrine therapy.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 71
    ISSN: 1573-7217
    Keywords: breast cancer ; histological grade ; lymph-node staging ; prognostic factors ; multivariate prognostic index ; survival ; tumour size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In primary, operable breast cancer, the Nottingham Prognostic Index (NPI) based on tumour size, lymphnode stage and histological grade can identify three prognostic groups (PGs) with 10-year survival rates of 83%, 52%, and 13%. With the aim of defining a subset of patients having so good prognosis that adjuvant therapy can be withhold, the NPI was applied to a Danish population-based study group comprising 9,149 patients. As opposed to the British study, we used conventional axillary lymph-node staging. Histological grading was in both studies done by means of a similar slight modification of the Bloom and Richardson procedure, but in the Danish study only ductal carcinomas were graded. The 10-year crude survival was 68.1% for 4,791 patients with tumour size ≤ 2 cm and 70.0% for 2,900 patients with grade I tumours. For 4,761 node-negative patients, the 10-year survival was also 70.0%, the expected survival being 89.3%. The relative mortality (observed:expected) was even at 10 years 2.1 demonstrating that more than 10 years observation time is necessary to estimate cumulated mortality. By application of the NPI, the Danish good PG comprising 27.3% of the patients had a 10-year survival of 79.0%. Thus, the index defined a subset with better survival than could be defined individually by each of its three components, but it did not succeed in defining a subset with survival similar to the expected; additional prognostic factors are therefore needed. The somewhat poorer survival of the Danish good PG may be ascribed to the British inclusion of non-ductal carcinomas, to interobserver variation present only in the Danish study, and to poorer expected survival of the Danish patients. The 10-year survival of the Danish moderate PG and poor PG was 56% and 25%, respectively. These improved survival rates are attributed to the administration of adjuvant therapies. There were virtually no node-positive patients in the good PG and no node-negative patients in the poor PG. Patients should therefore still be stratified initially by lymph-node status, but tumour size and histological grade are significant prognostic factors primarily within the node-negative group, and they should be included in future prognostication procedures.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    Breast cancer research and treatment 31 (1994), S. 83-94 
    ISSN: 1573-7217
    Keywords: antiestrogens ; breast cancer ; droloxifene ; clinical trial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Droloxifene, a new antiestrogen, has theoretical advantages over tamoxifen based on preclinical data. These include higher affinity to the estrogen receptor, higher antiestrogenic to estrogenic ratio, and more effective inhibition of cell growth and division in ER positive cell lines, as well as less toxicity, including reduced carcinogenicity in animal models. Droloxifene also exhibits more rapid pharmacokinetics, reaching peak concentrations and being eliminated much more rapidly than tamoxifen. A phase II study compared droloxifene in dosages of 20, 40, and 100 mg daily in postmenopausal women with metastatic, or inoperable recurrent, or primary locoregional breast cancer who had not received prior hormonal therapy. Of 369 patients randomized, 292 were eligible and 268 evaluable for response. Response rates (CR + PR) were 30% in the 20 mg group, 47% in the 40 mg group, and 44% in the 100 mg group (40 mg vs 20 mg, p = 0.02; 100 mg vs 20 mg, p = 0.04; pooled 40 + 100 mg vs 20 mg, p = 0.01). Median response duration also favoured the higher dosages (20 mg group = 12 months; 40 mg group = 15 months; 100 mg group = 18 months). When adjusted for prognostic factors, time to progression was significantly better for the 100 mg (p = 0.01) and the 40 mg (p = 0.02) group compared to the 20 mg group. Droloxifene increased SHBG and suppressed FSH at all dosages and suppressed LH at the 40 and 100 mg dosages. These hormonal effects increased with increasing dosage. Shortterm toxicity was generally mild, and similar to that seen with other antiestrogens. Droloxifene appears active and tolerable. It may have a particular role in situations in which rapid pharmacokinetics, or an increased antiestrogenic to estrogenic ratio, are required.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 73
    ISSN: 1573-7217
    Keywords: antiestrogens ; cell proliferation ; cell cycle ; cyclins ; breast cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The molecular mechanisms by which antiestrogens inhibit breast cancer cell proliferation are not well understood. Using cultured breast cancer cell lines, we studied the effects of antiestrogens on proliferation and cell cycle progression and used this information to select candidate cell cycle regulatory genes that are potential targets for antiestrogens. Under estrogen- and serum-free conditions antiestrogens inhibited proliferation of MCF-7 cells stimulated with insulin. Cells were blocked at a point in G1 phase. These effects are comparable with those in serum- and estrogen-containing medium and were also seen to a lesser degree in nude mice bearing MCF-7 tumors. Similar observations with other peptide mitogens suggest that the process inhibited by antiestrogens is common to estrogen and growth factor activated pathways. Other studies have identified G1 cyclins as potential targets for growth factor and steroid hormone/steroid antagonist regulation of breast epithelial cell proliferation. In MCF-7 cells growing in the presence of fetal calf serum, cyclin D1 mRNA was rapidly down-regulated by steroidal and nonsteroidal antiestrogens by an apparently estrogen receptor mediated mechanism. Cyclin D1 gene expression was maximally inhibited before effects on entry into S phase and inhibition was therefore not merely a consequence of changes in cell cycle progression. Together with data on the effects of antiestrogens in serum-free conditions [1], these results suggest down-regulation of cyclin D1 by antiestrogens may be a general phenomenon in estrogen receptor-positive breast cancer cells, independent of culture conditions and class of antiestrogen. These observations are compatible with the hypothesis that reductions in cyclin D1 levels may mediate in part the action of antiestrogens in blocking entry of cells into S phase.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 74
    ISSN: 1573-7276
    Keywords: breast cancer ; clonal dominance ; retroviral gene transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Human breast cancer cell lines which grow in athymic (nude) mice provide a model of tumor cell growth and metastasis. Marking transplanted tumor cell populations with retroviral vectors provides a means of studying the dynamics of tumor cell growthin vivo. We evaluated three human breast cancer cell lines, MDA-MB-435, MDA-MB-231 and MCF-7, and found the cells were highly susceptible to retroviral gene transfer after a single 2-h exposure (90.9%, 62.7% and 72.3%, respectively). MDA-MB-435 cells (5×105) marked with a retroviral vector containing theβ-galactosidase gene (approximately 104 uniquely marked clones) were injected into the mammary fat pad of athymic mice to study clonal dominance. Primary tumors resected 10 weeks after injection expressedβ-galactosidase, demonstrating persistent vector expressionin vivo. Southern blot analysis did not reveal clonal dominance in the primary tumors of the five mice studied. In contrast, pulmonary metastases in each animal were monoclonal or biclonal. These results demonstrate clonal dominance in pulmonary metastases but not primary tumors of retrovirally marked MDA-MB-435 cells. Our findings suggest that this model may also be used to introduce retroviral vectors expressing oncogenes, and anti-sense oncogenes, to determine their effect on tumor cell proliferation and metastasisin vivo.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 75
    ISSN: 1573-7225
    Keywords: Atomic bomb survivors ; breast cancer ; Japan ; reproductive history
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Women with breast cancer (cases=196) and without the disease (controls=566), selected from the Life Span Study sample of A-bomb survivors and nonexposed residents of Hiroshima and Nagasaki, Japan, and matched on age at the time of the bombings, city, and estimated radiation dose, were interviewed about reproductive and medical history. A primary purpose of the study was to identify strong breast cancer risk factors that could be investigated further for possible interactions with radiation dose. As expected, age at first full-term pregnancy was strongly and positively related to risk. Inverse associations were observed with number of births and total, cumulative period of breast feeding, even after adjustment for age at first full-term pregnancy. Histories of treatment for dysmenorrhea and for uterine or ovarian surgery were associated positively and significantly with risk at ages 55 or older, a finding that requires additional study. Other factors related to risk at older ages were the Quetelet index (weight [kg]/height [cm]2) at age 50, history of thyroid disease, and hypertension. Neither age at menarche nor age at menopause was associated significantly with risk. Subjects appeared to be poorly informed about history of breast cancer or other cancer in themselves or in their close relatives; this finding suggests that innovative strategies may be required when studying familial cancer patterns in Japanese populations.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 214 (1994), S. 57-65 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Positive und negative Photostrukturen wurden in einem Polyimid (PI) aus 4,4′-Biphthalsäureanhydrid (BPA) und 4,4′-Diamino-3,3′-dimethyldiphenylmethan (DADMDPM), PI(BPA/DADMDPM) erzeugt, nachdem dieses mit Michlers Keton (MK) bzw. Benzophenon (BP) dotiert und einer ultravioletten Strahlung von 400 ± 50 nm ausgesetzt und naß entwickelt wurde. Das Prinzip der positiven Abbildung basiert auf dem Photokupplungseffekt von MK mit PI, der die Löslichkeit des Polyimids erhöht und so die Entwicklung eines Positivmusters ermöglicht. Die Erzeugung negativer Muster wird durch intermakromolekulare Wasserstoffbrücken zwischen der Carbonylgruppe des Imid-Rings und der Hydroxygruppe, die bei der photoinduzierten Kupplung von Benzophenon mit dem Polyimid gebildet wird, bewirkt. Die lithographische Auswertung zeigt, daß der mit MK dotierte, positive Polyimidfilm nicht in der Lage ist, brauchbare Muster zu erzeugen, da die UV-Wellenlängen von MK absorbiert werden, wodurch die Photokupplung in den tieferen Schichten des Films verhindert wird. Andererseits können in dem 0,6 μm dicken, mit Benzophenon dotierten Polyimidfilm sogar 2 μm schmale Linien aufgelöst werden.
    Notes: Positive and negative photostructures are formed after the polyimide (PI) of 4,4′-biphthalic anhydride (BPA) and 4,4′-diamino-3,3′-dimethyldiphenylmethane (DADMDPM), PI(BPA/DADMDPM) is doped with Michler′s ketone (MK) and benzophenone (BP), respectively, and is subjected to UV light (400 ± 50 nm) irradiation and solvent development. The principle of positive feature formation is based on the photocoupling of MK with PI, which increases PI solubility and thus enables a positive pattern to be developed. The phenomenon of negative photopatterning results from intermacromolecular H-bonding between the carbonyl group of the imide ring and the hydroxy group which is formed in the photoinduced coupling reaction between BP and PI. Lithographic evaluation shows that the MK-doped positive-acting PI film cannot form useful patterns because UV wavelengths are strongly absorbed by MK, which limits the depth of photocoupling in the film. On the other hand, 2-μm-wide lines can be resolved in the BP-doped negative-acting 0.6-μm-thick PI film.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 214 (1994), S. 101-113 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polyhydrazid/Polyamid-Blends (PEHZ12/PA6) wurden durch Niedrigtemperatur-Polykondensation von 4,4′-Dichlorformyl-α,ω-diphenoxydodecan und Terephthaloyldihydrazid (TDH) zu Poly(etheraroylhydrazid) in Gegenwart von Polyamid 6 synthetisiert. Die DSC-Analysen lassen vermuten, daß die zwei Polymerkomponenten nicht wechselwirken. Bei der Extraktion des PA6-Anteils der Blends mit Ameisensäure zeigt die Charakterisierung des PEHZ12-Extraktionsrückstands aber, daß zumindest bei bestimmten Zusammensetzungen Wechselwirkungen zwischen den Komponenten auftreten. Modellreaktionen erlauben die Annahme, daß die PEHZ12-Polymerisation zwischen den Amino-Endgruppen des PA6 und den wachsenden PEHZ12-Polymerketten abläuft.
    Notes: Poly(etheraroylhydrazide) is synthesized in the presence of PA6 by means of low-temperature condensation polymerization of 4,4′-dichloroformyl-α,ω-diphenoxydodecane with terephthaloyl dihydrazide (TDH) in order to prepare polyhydrazide/poly-amide 6 (PEHZ12/PA6) blends. The thermal analysis of the blends by DSC seems to indicate that the two polymers are not interacting. Nevertheless, when the blends are subjected to an extraction process with formic acid in order to remove the PA6, the characterization of the residual PEHZ12 reveales that some interactions do occur between the constituent polymers, at least for selected compositions. Model experiments permit to hypothesize that the polymerization of PEHZ12 proceeds with a chemical interaction between amino end groups of PA6 and growing PEHZ12 chains.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 214 (1994), S. 179-196 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The crystallization behavior of PBT as well as PC is changed in the controlled-processed blend due to intermolecular interactions between the different macromolecules in molten state.If the kinetics of the crystallization process prevents a crystallization-induced separation, the partial miscibility of the amorphous phases, measured by the glass transition temperatures, will lead to a decrease of the crystallinity of PBT. The crystallinity, normalized to the concentration of PBT in the blend, is independent from the concentration of PC at low coolling rates.At high cooling rates, PBT is crystallizing stepwise in the blend PBT/PC 40/60 wt.-%. The crystallization temperature in the anisothermic crystallization process is increased at low contents of PC due to a changed nucleation mechanism. The half-time of crystallization is increasing in blends with an increasing PC-content in isothermic crystallization experiments.The normally amorphous PC crystallizes considerably fast in presence of PBT in PC-rich blends. The crystallization or change in the state of order of PC was measured in situ by X-ray diffraction. Calorimetric experiments confirm this result and allow a quantitative estimation of the PC-crystallinity, which amounts to some 20% in the blend PBT/PC 5/95 wt.-%.
    Notes: Das Kristallisationsverhalten sowohl von PBT als auch von PC ist im definiert verarbeiteten Blend infolge intermolekularer Wechselwirkungen zwischen den unterschiedlichen Molekülen in der Schmelze verändert.Die über die Glasübergangstemperaturen gemessene teilweise Mischbarkeit der amorphen Phasen führt bei PBT zu einer Erniedrigung des Kristallinitätsgrades, wenn die kinetischen Bedingungen des Kristallisationsprozesses keine kristallisationsbedingte Entmischung zulassen. Der auf den PBT-Anteil normierte Kristallinitätsgrad ist bei kleinen Abkühlgeschwindigkeiten vom PC-Anteil unabhängüg.In der Mischung PBT/PC 40/60 Gew.-% kommt es bei hohen Kühlraten zu einer fraktionierten Kristallisation. Die Kristallisationstemperatur bei anisothermer Kristallisation ist bei geringen PC-Gehalten durch Änderung des Keimbildungsmechanismus erhöht. Bei isothermer Kristallisation steigt mit zunehmendem PC-Anteil die Kristallisationshalbwertszeit des PBT an.Das normalerweise amorphe PC kann in Gegenwart von PBT in den PC-reichen Mischungen besonders schnell kristallisieren, wobei der Kristallisations- bzw. Ordnungsprozeß des PC in situ mittels der Röntgenbeugung gemessen wurde. Kalorimetrische Untersuchungen bestätigen dieses Ergebnis und erlauben eine quantitative Abschätzung des PC-Kristallinitätsgrades zu ca. 20% im Blend PBT/PC 5/95 Gew.-%.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 214 (1994), S. 197-210 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Elementaranalytische sowie NMR-, IR- und UV-spektroskopische Untersuchungen zeigen, daß die Photolyse von Halogenphenolnovolaken zur Substitution der Halogenatome durch Wasserstoff, der Bildung chinoider Gruppen und intermolekularen Vernetzung führt. Die Geschwindigkeit der Halogeneliminierung hängt von der Art des Halogens ab. Sie steigt in der Reihenfolge F 〈 Cl 〈 Br 〈 I. Die Chloreliminierung aus der 4-Position ist gegenüber der aus der 2- und 3-Position begünstigt. Außerdem verläuft die Abspaltung para-ständiger Chloratome aus Dimeren schneller als aus Trioder Tetrameren. ESR-Messungen bei 77 K sowie die Laserblitzphotolyse bei 296 K deuten auf die intermediäre Bildung von Phenoxyl- und Arylradikalen. Lithographische Tests belegen die hohe UV-Empfindlichkeit von Resisten auf der Basis von Halogenphenolnovolaken. Im Vergleich zu nichthalogenhaltigen Novolakresisten wird eine 6 - 10fache (System: 4-Chlorphenolnovolak/4,4′-Bisazidobiphenyl (5%)) bzw. eine ca. 25fache (System: 4-Chlorphenol-/m-Cresolnovolak/Hexamethoxymethylmelamin (5%)) Steigerung der Empfindlichkeit erreicht. Zur Interpretation wird ein Mechanismus postuliert, demzufolge die durch Halogenabspaltung hervorgerufene Sekundärradikalbildung zu einer zusätzlichen Vernetzung beiträgt. In den melaminhaltigen Resisten katalysiert der gebildete Halogenwasserstoff (Hal· + RH → H-Hal + R·) außerdem die Reaktion der Melaminverbindung mit der Novolakmatrix.
    Notes: The photolysis of halogenophenol novolacs is determined by the substitution of halogens by hydrogen and the formation of quinoid groups and intermolecular crosslinks. This is concluded from elemental analysis, NMR, IR and optical absorption measurements. The rate of halogen release depends on the chemical nature of the halogen. It increases in the order F 〈 Cl 〈 Br 〈 I. Chlorine elimination from 4-position is favored over that from 2- and 3-position. Moreover, dimers release chlorine from 4-position much more readily than trimers and tetramers. ESR measurements at 77 K and flash photolysis studies at 296 K yielded evidence for the intermediate existence of phenoxyl and aryl radicals. Lithographic tests demonstrated the high UV-sensitivity of resist formulations based on halogen-containing novolacs. The increase in sensitivity relative to that of formulations based on nonhalogenated novolacs is 6 to 10fold system: 4-chlorophenol novolac/4,4′-bisazidobiphenyl (5%) and ca. 25fold system: 4-chlorophenol/m-cresol novolac/hexamethoxymethylmelamine (5%). A postulated reactions mechanism concerning the sensitivity increase takes into account that halogen elimination results in the formation of additional radicals that accelerate the rate of crosslinking. Moreover, hydrogen halide generated by hydrogen abstraction of halogen radicals (Hal· + RH → H-Hal + R·) provides for the acid required to catalyze the reaction of the melamine compound with the novolac matrix.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 215 (1994), S. 11-24 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Calciumcarbonate unterschiedlicher Teilchenform (sphäarisch, kubisch und nadelfäormig) wurden mit Polypropylen (PP) in einer Zwei-Walzen-Mäuhle gemischt und anschließend zu Platten gepreßt. Der Einflußder Teilchenform auf das Kristallisationsverhalten der PP/CaCO3-Composite, d.h. Kristallisationspeaktemperatur (Tmax), Kristallisationsverlauf usw., wurde mittels Differentialkalorimetrie untersucht. Der Wert von Tmax häangt von der Größe der Gesamtoberfläache der CaCO3-Teilchen ab; Tmax ist bei nadelfäormigen Teilchen gräoßer als bei kubischen oder sphäarischen und hauangt in allen Fäallen der nicht-isothermen Kristallisation von der Abkäuhlgeschwindigkeit und der vorher erreichten maximalen Temperatur ab.
    Notes: Calcium carbonate of various particle shape (spheric, cubic, needle-shaped type) and polypropylene (PP) were mixed on a two roll mill and the mixture was pressed into plates. The effect of particle shape on the crystallization behavior of PP/CaCO3 composites, such as crystallization peak temperature (TMAX), crystallized pattern, etc., was investigated with differential scanning calorimetry measurements. The value of TMAX is explained by the total surface area of added CaCO3 particles; TMAX of needle-shaped series is larger than that of cubic or spheric ones. TMAX of various shaped CaCO3-filled PP totally depends on the cooling rate and maximum temperature in the non-isothermal crystallization, respectively.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 215 (1994), S. 107-119 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch Polyaddition von Polyethylenglykol (PEG) Oligoglycidylethern (Mn (PEG): 396,587, 1437 und 3554) mit asymmetrischen Diaminen, wie N,N-Dimethylund N,N-Diethyl-1,3-diaminopropan, wurden wasserläosliche kationische Polymere erhalten. Die Eigenschaften der kationischen Polymeren sind vom urspräunglichen PEG-Molekulargewicht und der Diaminreaktivitäat abhäangig. PEG mit Mn = 396 zeigt das beste Verhalten. In verdäunnten wäassrigen Läosungen und in wäassrigen 2M NaCl-Läosungen der Polymeren wurde das Polyelektrolytverhalten veranschaulicht. Die Gegenwart der PEG Kette bestimmt das Polyelektrolytverhalten in den 2M NaCl Läosungen.
    Notes: Water-soluble cationic polymers were obtained by polyaddition of poly(ethylene glycol) (PEG) diglycidylethers (M̄n of PEG were 396, 587, 1437 and 3554, resp.) with asymmetrical diamines such as N,N-dimethyl-1,3-diaminopropane and N,N-diethyl-1,3-diaminopropane. The cationic polymer properties depend on the PEG initial molecular weight and on the diamine reactivity too. PEG with M̄n = 396 had the best behaviour in these reactions. The polyelectrolyte feature of cationic polymers was emphasized both in dilute aqueous solutions and in 2M aqueous NaCl solutions. The polyelectrolyte behaviour in 2M aqueous NaCl solution is determined by the PEG chain presence.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 215 (1994), S. 139-145 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Reaktion von o-Kresol mit Formaldehyd wurde unter Verwendung verschiedener tertiäarer Amine als Katalysatoren untersucht. Der Einfluß der Reaktionsparameter Basizitäat, Temperatur, Reaktionszeit und Formaldehydkonzentration wird diskutiert. Für die bevorzugte Bildung von 2,4-Bis(hydroxymethyl)-6-methylphenol wurden optimierte Synthesebedingungen erarbeitet. Die Bildung von Zwei-bzw. Mehrkernprodukten konnte nicht ausgeschlossen werden.
    Notes: The reaction between o-cresol and formaldehyde was investigated using various tertiary amines as catalysts. The influence of the reaction parameters basicity, temperature, reaction time and concentration of formaldehyde was discussed. To yield preferentially 2,4-bis(hydroxymethyl)-6-methylphenol the conditions of synthesis were optimized. The formation of bi- and polynuclear products cannot be avoided.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 215 (1994), S. 189-200 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Scherviskositäat fläussigkristalliner Ethylcellulose, die mit Cellulosepulver unterschiedlicher Partikelgräoße gefäullt war, wurde bei konstantem Schergefäalle mit einem Kegel-Platte-Viskosimeter bestimmt. Der Einfluß des Cellulosepulvergehalts, des Läange/Breite-Verhäaltnisses der Pulverteilchen und der Temperatur auf das viskose Verhalten und die Phasenäubergäange wird diskutiert. Der Zusatz von Cellulosepulver erhäoht die Viskositäat und verringert die Aktivierungsenergie des Fließens(Ea), ohne jedoch die Phasenäubergäange zu beeinflussen. Die Viskositäat und die Aktivierungsenergie sind abhäangig vom Läange/Breite-Verhäaltnis der Pulverteilchen; mit zunehmender Gräoße dieses Verhäaltnisses wird die Viskositäatszunahme beschleunigt und die Aktivierungsenergie des Fließens erhäoht, wäahrend die Aktivierungsenergie mit steigendem Pulvergehalt abnimmt. Die Phasenumwandlungen sind unabhäangig von der Partikelform. Der Einfluß des Pulvergehalts auf Viskositäat und Aktivierungsenergie ist abhäangig von der Art der fläussigen Phase; in der anisotropen Phase ist der Einfluß geringer als in der isotropen Phase. Dies scheint von der Ausrichtung der Pulverteilchen und der stäabchenfäormigen Molekäule herzuräuhren.
    Notes: Steady-state shear viscosity for the liquid crystalline ethyl cellulose solution filled with cellulose powders was determined using a cone-plate-type viscometer and the effects of cellulose powder content, powder aspect ratio and temperature on the viscometric behavior and phase transformation were discussed. The addition of powder increased the viscosity and decreased the activation energy (Ea) for flow, but did not affect the phase transformation. The viscosity and Ea depended on the aspect ratio; with greater aspect ratio, the viscosity enhancement was accelerated and Ea as well as the decrease in Ea with powder content increased. The phase transformation did not depend on the aspect ratio, the dependences of viscosity and of Ea on powder content depended on the solution phase; the dependences for the anisotropic phase were smaller than those for the isotropic one. The findings appeared to originate from the alignments of powders and rod-like molecules.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 84
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The UV-degradation of an unstabilized and two HALS stabilized polyethylene (PE) films is described. The degradations are characterized by measuring the oxygen uptake, the formation of CO and CO2, the FT-IR spectra, the mechanical properties, the stabilizer concentration and the oxygen content of the film.The oxygen uptake of the unstabilized PE film led to the expected changes in the IR spectra and embrittlement of the film, while the oxygen uptake by the HALS stabilized films caused only minor changes. The differences between the results for the unstabilized and the HALS stabilized polymers are explained assuming that the initiation of the photodegradation of PE is due to charge transfer complexes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 85
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Principal chemical pathways characteristic of active participation of radical scavenging polymer stabilizers (phenols, aromatic, hydroaromatic and hindered aliphatic amines) are outlined. Pathways resulting in a partial depletion or distortion of activity of stabilizers, in formation of polymer discolouring products, or in interactions in bifunctional stabilizers are involved.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 86
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Irradiations (λ≥300 nm) of poly(butyleneterphtalate) films were carried out in both vacum and air. Photoproducts were investigated by FTIR spectroscopy, chemical derivatization reactions and physical treatments. The repartition of photoproducts in the polymer was shown to be heterogeneous. A scheme accounting for the main routes of PBT photolysis was found on the basis of photoproducts identification. Most of oxidation products were analogous to vacum photolysis species; the mechanism of photooxidation proposed implied both pure photolytical processes and a photo-induced oxidation route.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 87
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of polymer density, processing conditions (quenching of annealing), degree of crystallinity, size of crystallite and mobility of polymer chains on the photo-and radiation-induced degradation and the polymer stability have been studied by UV, FTIR spectroscopic, viscosity and mechanical property measurements. Four kinds of annealed or quenched polyethylene (PE) films varying densities were used to the studies. Polystyrene (PSt) films were used to investigate the effect of chain mobility on polymer degradation. The following results were obtained. 1.In linear low density (LLD) PE, greater amounts of crosslinking (irradiated in vacuum) and chain scission (irradiated in air) were noticed than in mediun density (MD) PE and high density (HD) PE samples.2.Polyene formation is favored in the case of the irradiation in vacuum for LLDPE.3.Polymer stability evaluated by mechanical property such as elongation at break (%) is superior in LLDPE to MDPE and HDPE for annealed and quenched samples.4.Segmental motion of polymer chain also affects the polymer stability
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 217 (1994), S. 43-49 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The study is on two component blends of high density polyethylenes, having normal and ultra-high molecular weight. The polyethylenes were homogenized by two routes: in powder state or by rolling in melt, then pressed at temperatures in the range from 140°C to 220°C. Comparative studies showed that the way of homogenizing of the components does practically not affect the main mechanical properties of the blends when pressed at temperatures ≥ 160°C. Of special interest are the characteristics of those systems where ultra-high molecular weight polyethylene is the matrix component.
    Notes: Untersucht wurden binäre Mischungen von Polyethylenen hoher Dichte rnit normaler und ultrahochmolekularer Molmasse, die auf zweierlei Weise - in Pulverform oder durch Walzen im Schmelzezustand - homogenisiert und bei Temperaturen zwischen 140 und 220°C gepreßt waren.Es wurde festgestellt, daß die Art der Homogenisierung der Komponenten praktisch keinen Einfluß auf die Eigenschaften bei Preßtemperaturen ≥ 160°C hat. Von besonderem Interesse sind die Eigenschaften der Systeme, in welchen das ultrahochmolekulare Polyethylen die Rolle der Matrixkomponente spielt.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 218 (1994), S. 81-109 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Verhalten eines neuartigen photoinitiierenden Systems, das die Polymerisation von pigmenthaltigen Schichten großer Dicke in einem Reaktionsschritt gestattet, wird dargestellt. Die verschiedenen Wechselwirkungen, die in einem pigmenthaltigen System auftreten, werden qualitativ beschrieben, und der Anteil der von einem Photoinitiator absorbierten Lichtintensität wird berechnet. Neben dem Absorptions- und Reflexionsverhalten von verschiedenen Pigmentklassen werden die optischen Eigenschaften verschiedener Strahlungsquellen untersucht, um die Strahlungsbereiche zu finden, die am besten mit den optischen Parametern der Pigmente korrespondieren. Weiterhin wird die Beschleunigung von Polymerisationen durch die photokatalytische Wirkung einiger Pigmente behandelt.
    Notes: Ce travail sur le rôe des pigments définit le comportement d'un nouveau systeme photosensible qui permet de polymériser des milieux épais et pigmentés selon un procédé en une seule étape. Les différentes interactions présentes en milieu pigmenté sont décrites de façon qualitative, et la part de l'intensité lumineuse absorbée par un photo-amorceur dans un systéme pigmenté est evaluée. Les propriétés optiques telles que l'absorption et la réflectance des différentes familles chimiques de pigments sont déterminées, et, en paralléle, les propriétés optiques des différentes sources d'irradiation sont étudiées de manière à répondre au mieux aux fenêtres de transmission des pigments. L'effet photocatalytique de certains pigments est mentionné, ceci afin d'amkliorer la réaction de polymérisation.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 90
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 218 (1994), S. 153-162 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Herstellung von cis-1,4-Polybutadien erfolgte mittels Polymerisation von 1,3-Butadien mit einem Katalysatorsystem, das in einer zweistufigen Reaktion gebildet wird: (1) BF3 · O(C2H5)2 und Al(C2H5)3, (2) Ni(OOC8H15)2 und Al(C2H5)3, genannt in-situ-Katalysatorsystem.Die Molmassenverteilungen (MMD) der erhaltenen Polymeren sind mit der Größenausschlußchromatographie (SEC) untersucht worden. Sie lassen sich mit Summen aus Schulz-Flory-Funktionen (SFF) beschreiben. Veränderte Katalysatorformierungs- und Polymerisationsbedingungen beeinflussen die Parameter der SFF. Veränderte Peakflächen und Molmassenmittelwerte der Einzelpeaks zeigen, daß die Polymerisation über mehrere Arten aktiver Zentren verläuft.
    Notes: Cis-1,4-polybutadiene was produced by polymerization of 1,3-butadiene using a catalyst system formed by a two-step formation, Namely (1) BF3 . O(C2H5)2 and Al(C2H5)3, (2) Ni(OOC8H15)2 and Al(C2H5)3 named in-situ-catalyst.The molar mass distributions (MMD) of the polybutadienes are investigated by means of size exclusion chromatography (SEC). The MMD's were fitted by a sum of Schulz-Flory-Functions (SFF). Changed catalyst formation and polymerization conditions influenced the parameters of the SFF. Changed areas and changed molar mass averages indicate a polymerization with more than one peak maximum and kind of active species and lead to a better understanding of the polymerization.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 219 (1994), S. 1-10 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch Umsetzung von Chromacrylat mit Bisphenol A und einem Überschuß Epichlorhydrin wurden neuartige Epoxid-Harze hergestellt. Epoxy-Äquivalentgewicht, Gehalt an Hydroxygruppen und hydrolysierbarem Chlor sowie die Viskosität wurden bestimmt, und die Harze wurden mittels IR- und 1H-NMR-Spektroskopie charakterisiert. Die thermischen Eigenschaften der bei 30°C für 24 h mit Ciba Geigy HY 850 (aliphatisches Amin) gehärteten Harze wurden gemessen. Die Harze besitzen eine gute thermische und chemische Stabilität und eine gute elektrische Leitfähigkeit. Die Reaktion verläuft nach erster Ordnung; die Aktivierungsenergie beträgt 47 kJ mol-1 bzw. 34 kJ mol-1 mit bzw. ohne Chromacrylat. Aus spektroskopischen Untersuchungen wird geschlossen, daß das Chrom mit Bisphenol A einen Komplex bildet, der die Epoxidierung beschleunigt.
    Notes: Novel epoxy resins containing chromium acrylate have been synthesized by reacting chromium acrylate with bisphenol-A and excess epichlorohydrin. The quantities such as epoxy equivalent weight, hydroxy content, hydrolyzable chlorine content and viscosity have been determined. The resins have been characterized by IR and 1H NMR spectroscopy. The cured resins were evaluated for thermal properties. The curing of resins was carried out with Ciba Geigy HY 850 (aliphatic amine adduct) at 30°C for 24 h. The cured resins have excellent thermal and chemical resistance, in addition to an excellent electrical conductivity. The reaction follows first order kinetics with an activation energy of 47 kJ mol-1 and 34 kJ mol-1 in the presence and absence of chromium acrylate, respectively. The chromium forms a complex with bisphenol-A, as indicated by spectroscopic studies, which increases epoxidation.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 219 (1994), S. 67-76 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Interpenetrierende Polymernetzwerke (IPNs) aus Polystyrol und Polyurethan auf der Basis von hydroxyterminiertem Naturkautschuk mit unterschiedlichen NCO/OH-Verhältnissen wurden unter verschiedenen Reaktionsbedingungen hergestellt und zu widerstandsfähigen Filmen verarbeitet. Die IPNs wurden durch ihre physikalischen, mechanischen und morphologischen Eigenschaften wie Dichte, Shore-A-Härte, Vernetzungsdichte, Zugfestigkeit und Reißdehnung charakterisiert. Mit steigendem Polystyrolgehalt erhöhen sich auch Dichte, Shore-A-Härte und Zugfestigkeit, während die Reißdehnung abnimmt. Die Untersuchungen der Vernetzungsdichte lassen eine Phasenumkehr vermuten.
    Notes: Interpenetrating polymer networks (IPNs) of polyurethane based on hydroxyterminated natural rubber with varying NCO/OH ratios and polystyrene were synthesized under different experimental conditions. These IPNs were found to make tough films. The IPNs were characterized by their physical, mechanical and morphological properties like density, Shore-A hardness, crosslink density, tensile strength and elongation at break. The IPNs exhibited an increasing trend in density, Shore-A hardness and tensile strength with increasing polystyrene content, while elongation at break decreased with similar variation in polystyrene content. The crosslink density measurements indicated a possible phase inversion process.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 219 (1994), S. 117-124 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß einer Plasmabehandlung von Ultrafiltrationsmembranen aus Polyethylen auf die Fouling- und Reinigungseigenschaften bei der Filtration von Rinderserumalbumin werden diskutiert. Bei 2,45 GHz erzeugtes Luft-Plasma steigert die Hydrophilie der Membranoberfläche von 0 auf 60%. Der Durchfluß bleibt bei 90 bis 99%. Mit Plasma behandelte Membranen sind leichter zu reinigen als unbehandelte; dennoch sind sie anfälliger für die Ablagerung von Rinderserumalbumin.
    Notes: The effect of plasma treatment of polyethylene ultrafiltration membranes on fouling and cleaning phenomena during filtration of bovine serum albumin solutions is discussed. Air-plasma of 2.45 GHz raises the membrane surface hydrophilicity from 0 up to 60%. The flux is maintained at 90-99%. Plasma-treated membranes are easier to clean than untreated polyethylene membranes. Despite that, the plasma-modified membranes are susceptible to more intensive deposition of albumin.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 219 (1994), S. 101-115 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Immobilisierung von Glucose-Oxidase in einer Poly(vinylalkohol) (PVAL)-Membran in Gegenwart von UV-Photoinitiatoren wurde untersucht. Enzym-Membranen wurden aus PVAL-Diazoharz- und PVAL-Photoinitiator-Systemen durch Vernetzung mit UV-Licht hergestellt. Mit diesen immobilisierten Glucose-Oxidase-Membranen wurde eine wirkungsvolle Enzymelektrode entwickelt, deren Eigenschaften untersucht wurden. Der Einfluß der Photoinitiatorkonzentration in Poly(vinylalkohol) und der UV-Bestrahlungsdauer auf den Grad der Unlöslichkeit sowie die Aktivitätsausbeute der Membran wurden mit Glucose als Substrat untersucht. Temperatur- und pH-Abhängigkeit der relativen Aktivität, Stabilität bei mehrmaligem Gebrauch, Lagerstabilität und Kalibrierungsdiagramme der Enzym-Membranen wurden ermittelt. Eine beim Erstgebrauch auftretende Instabilitätserscheinung der Membranen wurde ebenfalls untersucht.
    Notes: A study of the immobilization of glucose oxidase on a poly(vinyl alcohol) (PVAL) membrane in the presence of UV sensitizers was carried out. Enzyme membranes were prepared from PVAL-diazoresin and PVAL-sensitizer systems, crosslinked by means of UV irradiation. An effective enzyme electrode was developed by using the immobilized glucose oxidase membrane, and its characteristics were investigated. The effects of the concentration of sensitizers in poly(vinyl alcohol) and UV irradiation time on the degree of insolubility as well as the activity yield of the membrane were examined for the immobilized glucose oxidase using glucose as a substrate. Temperature and pH dependences of the relative activity, stability in repeated use, storage stability and calibration plots of the enzyme membranes were evaluated. The unstability phenomenon, found in the initial use of the immobilized glucose oxidase membrane, which was prepared from PVAL-sensitizer system, was also investigated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 219 (1994), S. 11-26 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Biopol, Biocellat and Mater-Bi, three biologically decomposable plastics have been tested for their use in medical industries. Biopol did not loose its stress and stiffness under sterilisation, and was also resistant against temperature and alcohol. Mater-Bi and Biocellat, the two other materials, did not satisfy the test applications. Water vapor sterilisation, temperature up to 60°C, at higher temperatures this material will embrittle.
    Notes: Für den Einsatz biologisch abbaubarer Kunststoffe in der pharmazeutischen Industrie und Medizintechnik wurden Produkte verschiedener Hersteller, wie Biopol, Biocellat und Mater-Bi untersucht. Dabei zeigte vor allem Biopol das notwendige Anforderungsprofil, d.h. die Anwendbarkeit aller Sterilisationsverfahren ohne Festigkeitsbzw. Steifigkeitsverluste sowie Temperatur- und Alkoholbeständigkeit. Dagegen wiesen die Werkstoffe Mater-Bi und Biocellat einige Schwachstellen auf. Bei Mater-Bi lagen diese bei der Wasserdampfsterilisation sowie bei der geringen thermischen und Medienbeständigkeit. Biocellat versprödet dagegen durch die erhöhte Temperatur bei der Dampfsterilisation, d.h. daß ein Einsatz über 60°C nicht möglich wäre.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 96
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Alkylierung von Poly(5-vinyltetrazol) mit Dimethylsulfat und tert-Butylalkohol sowie Alkylhalogeniden RHal (R=CH3, C2H5, CH2—CH=CH2, n-C4H9 und t-C4H9) und die Kinetik dieser Reaktion wurden untersucht, um eine neue Herstellungsmethode für tetrazolhaltige Polymere mit wertvollen Eigenschaften zu entwickeln. Die vergleichenden Untersuchungen über die isomere Zusammensetzung und die spektroskopischen Daten von Poly(N-alkyl-5-vinyltetrazol)en, die durch die Alkylierung von Poly(5-vinyltetrazol) sowie durch die Copolymerisation der entsprechenden Monomeren hergestellt wurden, wurden mit IR-, 1H-NMR- und 13C-NMR-Spektroskopie durchgeführt. Der Alkylierungsumsatz beträgt bis zu 99,8%; dadurch können polymere Produkte erhalten werden, deren Zusammensetzung, Struktur und Eigenschaften denen der Homo- und Copolymeren sehr ähnlich sind.
    Notes: Alkylation of poly(5-vinyl tetrazole) with dimethyl sulfate and tert-butyl alcohol as well as with alkyl halides RHal (R=CH3, C2H5, CH2—CH=CH2, n-C4H9, t-C4H9) has been studied under various conditions in order to develop a new method of synthesis of tetrazole-containing polymers having a complex of valuable properties. The kinetic study of the process and comparison of isomeric compositions and spectroscopic characteristics (IR, 1H NMR and 13C NMR) of poly(N-alkyl-5-vinyl tetrazole)s synthesized by alkylation of poly(5-vinyl tetrazole) and of those prepared by (co)polymerization of the corresponding vinyl tetrazoles have been carried out. The alkylation is found to proceed to high conversion extents (up to 99.8%) and enables to obtain a wide variety of polymeric products having the composition, structure and properties very similar to those of homo- and copolymers.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 97
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Farbstoffe mit nichtlinearen optischen Eigenschaften wurden in einer zweistufigen Synthese aus 2-Hydroxyethylmethacrylat (HEMA), 4-Carboxybenzaldehyd und verschiedenen Anilinderivaten hergestellt. Die Farbstoffe (aromatische Iminester von HEMA) wurden mit Styrol copolymerisiert, die erhaltenen Copolymere wurden mit DSC sowie IR-, 1H NMR- und UV-VIS-Spektroskopie charakterisiert, und ihre nichtlinearen Eigenschaften wurden untersucht. Es zeigte sich, daß die nichtlinearen Koeffizienten d31 und d33 vom Farbstoffgehalt der Copolymeren und der Art der elektronenspendenden Gruppen abhängig sind.
    Notes: Dyes for nonlinear optics have been synthesized in two steps from 2-hydroxyethyl methacrylate (HEMA), 4-carboxybenzaldehyde and various substituted anilines. The obtained dyes (aromatic imine esters of HEMA) have been copolymerized with styrene, the copolymers characterized by DSC as well as IR, 1H NMR and UV-VIS spectroscopy, and studied for their nonlinear properties. The d31 and d33 nonlinear coefficients proved to be dependent on the dye content of the copolymers and on the nature of electrondonating groups.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 220 (1994), S. 123-132 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß von Ca2+-bzw. Al3+-Ionen auf das Viskositätsverhalten (Salzverträglichkeit) wäßriger Lösungen von Natriumcarboxymethylcellulose (CMC) sowohl mit unterschiedlichem Polymerisationsgrad (DP) als auch mit unterschiedlichem Substitutionsgrad (DS) und verschiedenartiger Substitutentenverteilung wurde untersucht. Aus Viskositätsmessungen mit einem Rotationsviskosimeter bei einer Scherrate von 500 s-1 geht hervor, daß die relative Abnahme der Viskosität im Ergebnis des Zusatzes der mehrwertigen Metallkationen unabhängig vom DP (im Bereich von 160 bis 900) der CMC ist. Homogen hergestellte CMC-Proben 2 mit einem größeren Gehalt an 2,3,6-Tri-O-carboxymethylglucose-Einheiten in der Polymerkette weisen im Vergleich zu heterogen hergestellten CMCs 1 bei gleichem Gesamt-DS eine höhere Salzverträglichkeit auf.
    Notes: The influence of Ca2+-and Al3+-ions, respectively, upon the viscosity behaviour (so-called salt tolerance) of aqueous solutions of sodium carboxymethyl cellulose (CMC) with different degree of polymerization (DP) and, on the other hand, with both different degree of substitution (DS) and distribution of substituents, was investigated. Viscosimetry by means of a rotational rheometer at a shear rate of 500 s-1 shows that the relative drop in viscosity as a result of addition of the multivalent metal cations is independent of DP (ranging from 160 to 900) of the CMC samples. Homogeneously synthesized CMCs (2) with a higher content of 2,3,6-tri-O-carboxymethyl glucose units in the polymer chain possess a significantly higher salt tolerance than those (1) prepared under heterogeneous reaction conditions at comparable total DS values.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 222 (1994), S. 61-87 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Melamin-Formaldehyd-Harz-Formmassen (MF) wurden durch mechanisches Mischen mit Ethylen-Vinylacetat-Copolymeren (EVA) und teilverseiftem EVA modifiziert, wobei Etherbindungen zwischen dem hydrolysierten EVA und dem MF-Harz nachgewiesen werden konnten, die die mechanischen Eigenschaften von spritzgepreßten Formteilen im Vergleich zur Modifizierung mit EVA verbessern. Der Zusatz solcher Modifikatoren erhöht die Duktilität und verringert im Falle von EVA die Nachschwindung der überaus steifen MF-Matrix, solange der Modifikatoranteil gering bleibt. Dagegen werden die Steifigkeit und die Wärmeformbeständigkeit verschlechtert. Die durch solche unvernetzten Polymeren erreichbare Steigerung der Schlagzähigkeit bleibt allerdings unzureichend.
    Notes: Melamine-formaldehyde moulding compounds (MF) were modified by mechanical mixing with ethylene/vinyl acetate copolymers (EVA) and with partially hydrolysed EVA. Ether linkages between the hydrolysed material and the MF resin improve the mechanical properties of the transfer moulded parts containing the hydrolysed material compared to those made with EVA. The use of both modifying polymers improves the ductility and, in case of the partially hydrolysed material, the postshrinkage of the extremely rigid MF matrix, as long as the modification polymer content is kept low. On the contrary, Young's modulus and the heat deflection temperature are deteriorated. The improvement in impact strength by use of those uncrosslinked polymers is still insufficient.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 222 (1994), S. 111-123 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine Reihe von Copolyesteramiden mit Molekulargewichten zwischen 1000 und 7000 (GPC, NMR) wurden aus Adipinsäure/1,6-Hexandiamin/∊-Caprolacton bzw. Nylon 6,6-Salz/∊-Caprolacton hergestellt. Die thermischen Eigenschaften der synthetisierten Polymeren (Glasübergangs-, Schmelz-, und Zersetzungstemperaturen, Schmelzenthalpien) wurden durch DSC- und TGA-Messungen bestimmt und in Bezug auf das Comonomerverhältnis in der Ausgangsmischung diskutiert. Die Übereinstimmung der Copolymerzusammensetzung mit dem Ausgangscomonomerverhältnis wurde mit FT-IR- und NMR-Spektroskopie untersucht. Die Bioabbaubarkeit der Copolyesteramide wurde durch enzymatische Hydrolyse geprüft.
    Notes: A series of copolyesteramides based on adipic acid/1,6-hexane diamine/∊-caprolactone and Nylon 6,6 salt/∊-caprolactone were synthesized. Their molecular weights, determined by gel permeation chromatography and NMR spectroscopy, were found to lie within the range from 1000 up to 7000. Their thermal properties (glass transitions, melting points and heats of melting, and decomposition temperatures) were recorded with diferential scanning calorimetry and thermogravimetry, respectively, and correlated to the comonomer feed composition. The FT-IR and NMR spectra were also recorded in order to confirm the composition of the copolyesteramides and to compare them with that of the comonomer feed. The biodegradability of the synthesized copolymers was tested by enzymatic hydrolysis.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...