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Biomedical subjects

A Rejthar

Publications and source records attributed to A Rejthar.

At least 37 records · Page 2Linked to original sources
PubMed1991

Effects of tissue fixation conditions and protease pretreatment on immunohistochemical performance of a large series of new anti-keratin monoclonal antibodies: value in oncopathology.

A comparative study with 21 recently raised monoclonal antibodies (3 of which are reported here for the first time) to human keratin polypeptides was performed on a wide range of paraffin-embedded tissues and tumors, aimed at the examination of effects of four different fixatives and protease pretreatment on the immunohistochemical detection of keratins. Our data demonstrated that: (a) formaldehyde-based fixatives modified by acidification and/or addition of methanol gave results superior to those achieved by routinely used formol saline; (b) relatively rare antibodies (4 out of 21) could be identified which gave reliable immunostaining patterns even on routine formalin-fixed material; (c) a proteolytic digestion step preceding the immunostaining was beneficial for the performance of the majority of antibodies in our panel. Additional options which could potentially lead to further improvement of keratin immunohistochemistry in paraffin embedded specimens are also suggested. This work provides the necessary basis for wider application of the anti-keratin antibodies of the C-series in both routine oncopathology and research-oriented retrospective studies.

Adenocarcinoma↗
PubMed1991

Aberrant expression of the p53 oncoprotein is a common feature of a wide spectrum of human malignancies.

Accumulation of the p53 protein was analysed in 212 human malignant lesions. Immunohistochemical staining with new polyclonal (CM-1) and monoclonal antibodies (BP 53-12 and BP53-24) to p53 on methacarn-fixed paraffin sections showed positive staining in 161 (76%). The positive tumours were found across a wide range of human malignancies including breast, colon, stomach, bladder and testis carcinomas, soft-tissue sarcomas and melanomas. The staining was always confined to the malignant lesion. Immunoprecipitation and quantitative ELISA assays established that the positive staining was associated with accumulation of the protein and that the protein was frequently in a mutant conformation. Accumulation of mutant p53 protein is therefore a common feature of human malignant disease.

Antibodies↗
PubMed1990

Patterns of expression of the p53 tumour suppressor in human breast tissues and tumours in situ and in vitro.

An extensive series of histological sections reflecting the various states of normal breast tissue, and a range of benign and malignant lesions, were examined for the expression of the p53 protein using a panel of anti-p53 antibodies. In 2 separate series the results of using frozen or methacarn-fixed, paraffin-embedded sections were compared. Strong positive staining for p53 was detected in over 50% of the malignant lesions when frozen sections were used. This number fell to just over 20% when methacarn-fixed sections were examined. In neither series was any p53 staining seen in normal breast or in the benign lesions. Studies by Western blotting on breast cell lines confirmed that this histological signal is due to a pronounced over-expression of the p53 protein. Earlier studies show that this over-expression is associated with mutation of the p53 gene. Mutation of the p53 gene with over-expression of the mutant protein is therefore one of the most frequent specific genetic changes in malignant breast cancer.

Antibodies, Monoclonal↗
PubMed1990

A panel of monoclonal antibodies to keratin no. 7: characterization and value in tumor diagnosis.

Reactivity patterns of seven mouse monoclonal antibodies to human keratin 7 were compared using immunoblotting and immunohistochemistry on cultured cells and normal human and animal tissues. Differences in keratin specificities as determined by two-dimensional immunoblots and interspecies cross-reactivity data on 8 mammalian species suggest that at least six nonidentical epitopes of the keratin 7 molecule are recognized by this panel of reagents. Immunohistochemical examination of a panel of various human neoplasms with monoclonal antibodies monospecific for keratins 7, 18 and 19 revealed potential value of keratin subtyping in differential diagnosis of tumors in general and in subclassification of carcinomas in particular.

Animals↗
PubMed1990

[Cystosarcoma phyllodes].

From a total number of 31 patients with the diagnosis of cystosarcoma phyllodes recorded by the authors, in two thirds the benign and proliferating form of the tumour was involved, in one third a malignant type of tumour. In benign tumours it is sufficient to extirpate the tumour completely, incl. capsule of the tumour. In malignant forms radical modified mastectomy with revision of the axilla must be performed. When the histological findings have a high grading (non-differentiated anaplastic), adjuvant radiotherapy or a combination of radiotherapy and chemotherapy must be used. Dispensarization of patients with the diagnosis of cystosarcoma phyllodes is essential.

Adolescent↗
PubMed1990

Multinucleated tumor cells and malignant melanoma.

Multinucleated cells (MC) were counted in cell preparations obtained by dissociation of representative part of tumor lesions immediately after excision. MC were present in almost all specimens examined (39 advanced primary lesions, 90 lymph node metastases and 33 dermal plus subcutaneous metastases); in one third of the samples they were very rare (less than 1% of all cells). There were no significant differences in quantity of MC between primary tumors, node metastases and dermal plus subcutaneous metastases, between node metastases seen early in the course of the disease and those seen later, and between regional node metastases taken from Stage II patients with rapidly progressing disease and regional node metastases taken from patients of the same stage whose disease-free intervals were longer. No unique pattern of similarities or differences in quantity of MC was found when comparing autologous tumor samples excised simultaneously and/or successively during the course of the disease.

Cell Nucleus↗
PubMed1989

Secretory component in differentiating normal epithelium, benign lesions and malignancy in the human breast as monitored by monoclonal antibodies.

An immunohistochemical study of the expression of the secretory component (SC) in human mammary gland epithelium at various stages of differentiation, as well as in benign and malignant breast tumours, was undertaken using three mouse monoclonal antibodies. Antibody RICEO-SC-05 (SC-05), raised against a partially purified preparation of human SC, and reacting with a reduction-resistant epitope present in both free and polymeric immunoglobulin-bound SC, was compared in immunoperoxidase and immunofluorescence studies on a diverse range of normal tissues, to 2 reference anti-SC antibodies (LICR-LONLC28 and RICEO-MFG-12). All three antibodies reacted with secretory epithelia only, consistent with known patterns of expression of SC in tissues, although there was an unexpected reaction by all anti-SC antibodies with some Hassal's corpuscles of the thymus. Staining patterns seen in the normal resting, pregnant, lactating and regressing (after weaning) breast provide evidence for differentiation-associated changes in the production of SC, and support the concept of terminal ductal lobular units (TDLUs) as functional compartments of the mammary gland. SC was detected in all but one benign breast lesion (n = 53) as compared to only 24% positive cases with heterogeneous expression of SC found among 176 primary and metastatic breast carcinomas examined. In a series of 40 primary breast carcinomas and their corresponding lymph node metastases, a good overall correlation was found between the expression of SC in the matched specimens; aside from 3 heterogeneously SC-positive carcinomas whose metastatic counterparts were SC-negative. Our results demonstrate a potential application for monoclonal antibodies to SC in the study of human mammary gland differentiation, but suggest that the value of an assay for SC in the diagnosis of breast carcinomas is questionable due to the generally low expression of SC by either primary or metastatic breast lesions.

Antibodies, Monoclonal↗
PubMed1989

HLA-DR antigen expression on melanoma metastases and the course of the disease.

Melanoma cells freshly isolated from regional lymph node metastases of 59 stage II malignant melanoma patients were analyzed by indirect immunofluorescence staining with monoclonal antibody TAL 1B5, detecting the HLA-DR alpha chain. The expression of HLA-A,B,C antigens, using antibody W6/32, was also investigated in 45 of these cases. There were no substantial differences in the course of the disease with respect to the percentage of positive cells. In 13 malignant melanoma patients two to four simultaneous and/or successive metastases (both locoregional and distant-subcutaneous) were analysed for HLA-DR. With simultaneous metastases (7 cases) the percentage of HLA-DR-positive cells was mostly very similar, and in no case was there more than 25% variation. As to successive metastases (9 cases) the percentage of HLA-DR-positive cells remained practically unchanged or decreased during the course of the disease.

Adult↗
PubMed1989

Monoclonal antibodies recognizing different epitopes of cytokeratin No.18.

A comparative study of six mouse monoclonal antibodies against human 45 kDa keratin polypeptide (keratin No. 18) was undertaken using three experimental approaches: immunohistochemistry on normal human tissues, examination of interspecies cross-reactivity and identification of the target polypeptides in 1-D and 2-D immunoblots. The data suggest that at least five different antigenic sites of keratin 18 are recognized by this panel of reagents. The C-04 epitope is keratin 18-specific and widely conserved among mammalian species, while the antibodies DA7 and DC10 also react specifically with the 45 kDa keratin but stain simple epithelia of human origin only. Two antibodies, C-11 and C-66, decorate simple as well as stratified epithelia in human and in all seven animal species tested, but their respective target epitopes are shared by different groups of keratin polypeptides, which indicates their non-identity. In contrast to keratin specificity of the five above mentioned antibodies, the C-08 antibody cross-reacts with a 70 kDa nuclear lamina protein found in human and bovine tissues. The results of the present study provide the necessary basis for future applications of these antibodies in both routine immunodiagnostic work and as probes to study the biology of epithelial cells in general and the significance of keratin intermediate filaments in particular.

Animals↗
PubMed1989

Phenotypic variability of chemically induced primary rat mammary tumors.

Rat mammary tumors induced by DMBA (7,12-dimethylbenz(a)anthracene) or MNU (N-methyl-N-nitrosourea) were compared for frequency of histological types. Total tumor incidence in 50-day-old rats (Groups 3, 4, 5) was about 100% independently of the rat strain and carcinogen. There were found no distinct histological tumor types between DMBA and MNU carcinogenesis, although the distribution of fibroadenomas, adenocarcinomas and sarcomas varied markedly among rat groups. In 300-day-old female Wistar rats (Group 1) treated with DMBA, fibroadenomas and adenocarcinomas showed an incidence of 58% and 42% respectively. In 50-day-old rats (Group 3) the proportion of adenocarcinomas increased up to 72% of total DMBA tumors. MNU carcinogenesis induced adenocarcinomas in 98% of total tumors in the Lewis rat strain (Group 5), while only 53% in Wistar rats (Group 4). The rest of tumors were sarcomas occurring in opposite ratio to adenocarcinomas. The relatively high susceptibility of connective tissue to MNU as compared with mammary epithelium was due to the mode of MNU administration and seemed to be strain dependent. Both DMBA and MNU carcinogenic systems are valuable experimental models of mammary tumor. The cell phenotypes of the resulting tumors can be predicted with high probability by the choice of dose regimen of carcinogen and the route of its application.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

Immunohistochemical localization of alpha-lactalbumin in human breast cancer tissue.

One hundred and eleven formalin-fixed breast cancer tissue samples were examined for the presence of alpha-lactalbumin using our polyclonal antibodies to this specific milk protein. Alpha-lactalbumin was shown to be present in 67 tumor samples (60%), in 15% of cases the occurrence of alpha-lactalbumin was questionable. No relationship was found between alpha-lactalbumin positivity and the histological type of the tumor, differentiation grading, type of invasivity, or stromal reactivity. Disease progression occurred in an equal number of patients with tumors either alpha-lactalbumin positive or negative. However, negativity was often connected with a disease-free interval shorter than 24 months after primary operation.

Breast Neoplasms↗
PubMed1989

Complex biochemical analysis of human breast tumor tissue.

The quantitative biochemical analysis of tissue specimens from 76 human breast carcinomas consisted of examination for cytosolic estrogen receptors (cER), nuclear estrogen receptors (nER), progesterone receptors (PgR), 1,25-dihydroxycholecalciferol receptors (DR), carcinoembryonic antigen (CEA), alpha-lactalbumin (aLA), and gamma-glutamyl transferase (gGT). The highest incidence was found in CEA (76%), DR (70%), and aLA (62%). There was a high percentage of tumors containing only DR, in contrast to the tumors containing only cER or PgR. The simultaneous occurrence of DR and CEA was considerably high (61%). No statistically significant differences were observed in these biochemical parameters in relation to the grade of differentiation of the tumors. The values of aLA in tumors that invaded lymphatic or blood vessels were lower as compared to those tumors that invaded adipose or connective tissues. The level of statistical significance of this difference was close to 5%, the differences in other parameters were statistically insignificant. For prognosis assessed at the time of surgery, after a 2-3-year follow-up of 36 patients the level of gGT in the tumor seems to be the most promising prognostic factor. The values of gGT were significantly lower in those patients whose tumors were in progression during this time. The significance of nER and aLA was also taken into consideration.

Breast Neoplasms↗
PubMed1989

[Prognosis in patients with intraocular malignant melanoma].

Based on previous work from the same department the authors analyzed risk factors in patients after enucleation of the eye with an intraocular melanoblastoma of the tunica vasculosa. Similarly as the majority of other authors, they found that the most important factors were the cellular type of the tumour, the size of the base, the site, and age of the patient.

Eye Enucleation↗
PubMed1988

Monoclonal antibodies against individual cytokeratins in the detection of metastatic spread.

A panel of 17 monoclonal antibodies (MAbs) recognizing various keratin polypeptides has been used to define their binding on non-epithelial elements in 28 bone-marrow samples and 14 lymph nodes, in order to establish their limitations for use as a possible tool for immunodiagnosis of carcinoma spread. Immunocytochemical studies have shown that only 8 antibodies consistently exhibited no false-positive staining of marrow cells. All the remaining MAbs labelled (mostly in a non-specific manner) a few cells of marrow samples derived from patients with either haematological disorders or malignant lymphomas. Fine granules and droplet-like cytoplasmic inclusions were predominant patterns of positive reactions. Homogeneous cytoplasmic staining reminiscent of specific keratin immunolabelling was occasionally seen as well. The positive cells could be also identified in some lymph nodes free of tumour infiltration. All antibodies visualized cytoplasmic droplets in scattered cells of lymph nodes taken from a patient with non-Hodgkin lymphoma. This type of positivity was mostly associated with positive histochemical reactions for iron. Quite significant was the detection of fibrillar positivity in the extrafollicular reticular cells in all nodes examined. Such a specific type of staining was exclusively induced by antibodies directed against epitopes of keratin 8 and 18, whereas those MAbs recognizing keratin 7 and 19 always gave negative results. Our data indicate that caution is required when such MAbs, considered as markers of specific cell types, are being used as an immunodiagnostic tool to identify single carcinoma cells. A series of criteria, including morphological ones, must be utilized in order to obtain meaningful results.

Antibodies, Monoclonal↗
PubMed1988

Novel monoclonal antibodies defining epitope of human cytokeratin 18 molecule.

Two monoclonal antibodies, DA7 and DC10, were obtained from fusions of mouse myeloma cells with splenic lymphocytes from mice immunized with human breast cancer cells of PMC 42 line. The indirect immunofluorescence studies performed on established tumor cell lines together with immunoperoxidase staining of normal human tissues showed that the components reacting with the antibodies were cytokeratins. Positive reaction was noted in all epithelia derived cultured cells and in all simple epithelial tissues known to express keratin 18. Immunoblotting performed on various cytoskeletal preparations demonstrated strong staining of a single band with a mobility corresponding to that of cytokeratin 18 (45 kD). The negative immunoperoxidase reaction found in different epithelial tissues of seven animal species suggests that both antibodies are specific for human keratin 18. It was shown that DA7 and DC10 antibodies exhibited strong reaction in paraffin embedded tissues fixed in either methacarn or standard formalin. These characteristics predetermine both antibodies as suitable reagents for the specialized histopathological work.

Animals↗
PubMed1988

DNA content and MHC class II antigen expression in malignant melanoma: clinical course.

To assess the clinical value of two comparatively new properties (DNA content and MHC class II antigen expression (HLA-DR, DP, DQ) of melanoma cells) which have been independently reported to reflect the outlook for patients with malignant melanoma, we investigated retrospectively 50 stage I nodular melanomas in two comparably homogeneous groups of 23 and 27 patients, the course of whose disease differed at five years. Flow cytometry and immunohistology were used on paraffin wax embedded archival material for the analysis of DNA ploidy and detection of class II antigens, respectively. A close association was found between class II antigen expression, detected by monoclonal antibody CR3/43 (antimonomorphic DR, DP, DQ) present in 23 of 50 (46%) melanomas and unfavourable clinical course (p less than 0.005, by log rank test), but no such association was found for DNA ploidy. It is suggested that immunohistology for MHC class II antigen expression may help to predict the behaviour of nodular melanomas whereas the prognostic value of DNA ploidy is more limited. The finding that class II positive cells are found predominantly in melanomas with a substantially increased risk of metastases has implications both for concepts of tumour heterogeneity and host immunity.

Antigens, Neoplasm↗