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Query: UMLS:C0268596 (EMA)
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Antigen retrieval (AR) incorporating high-temperature microwave (MW) heating of tissue sections before immunostaining is a revolutionary technique that can unmask the antigens in formalin-fixed tissue sections, thus making them available for immunohistochemical staining. Although high temperature is believed to be the primary mechanism in retrieval of antigens, a variety of chemical solutions have been tested to define an optimal AR solution. We tested the hypothesis that pH of the AR solution may influence the quality of immunostaining by using seven different AR buffer solutions at a series of different pH values ranging from 1 to 10. We evaluated the staining of monoclonal antibodies to cytoplasmic antigens (AE1, HMB45, NSE), nuclear antigens (MIB-1, PCNA, ER), and cell surface antigens (MT1, L26, EMA) on routinely formalin-fixed, paraffin-embedded sections under different pH conditions with MW heating for 10 min. The intensity of immunostaining was graded in a blinded fashion. The pH value of the AR buffer solution was carefully measured before, immediately after, and 15 min after the AR procedure. The influence of pH on AR immunohistochemical staining can be summarized into three patterns. Some antigens (L26, PCNA, AE1, EMA, and NSE) showed excellent retrieval throughout the pH range. Other antigens (MIB1 and ER) showed strong intensity of immunohistochemical staining at very low pH and at neutral to high pH, but a dramatic decrease in the intensity of the AR immunostaining at moderately acidic pH (pH 3-6). Still others (MT1 and HMB45) showed increasing intensity of the AR immunostaining with increasing pH, but only weak immunostaining at low pH. Among the seven buffer solutions at any given pH value, the intensity of AR immunostaining was very similar. However, Tris-HCl buffer tended to produce better results at higher pH, compared with other buffers. Although high-temperature heating is believed to be the most important factor for the AR technique, the pH value of the AR solution is an important co-factor for some antigens. Optimization of the AR system should therefore include optimization of the pH of the AR solution. Our results indicate that AR immunostaining of Tris-HCl or sodium acetate buffer at pH 8-9 may be suitable for most antigens, although certain nuclear antigens show optimal staining at low pH.
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PMID:Antigen retrieval immunohistochemistry under the influence of pH using monoclonal antibodies. 782 75

Microwave oven (mwo) is used to stimulate tissue fixation and to retrieve antigens damaged by fixation. Heavy metal salt solutions, water, and citric acid buffer (cab) have been suggested for this purpose. A serie of tumors treated with cab and phosphate-buffered saline (pbs) with mwo were studied immunohistochemically with 24 antibodies. Controls were treated in the same way, except for microwaving. The antibodies were directed against antigens of the following tumors: breast and prostate carcinoma, carcinoid, lymphoma and melanoma. The results showed that cab enhanced the immunoreactivity of the following antigens: estrogen receptors (AMAC), progesterone receptors (Novocastra), HMB45, vimentin, leukocyte common antigen, PCNA, p53, MIB-1 (Ki-67) and prostatic specific antigen. The antigens that did not improve their immunoreactivity, when compared with the control series were: factor VIII, keratin, Leu 22, L26, neuron-specific enolase, CEA, chromogranin, HBME-1, smooth muscle actin and EMA. Microwaving equally improved protein S100 and desmin either with cab or pbs. The only antigen that improved with pbs was actin. The results with B72.3 and NKI/C3 were poor and not reliable. In conclusion microwaving with cab enhances the immunoreactivity of the antibodies mentioned above leading to an increase in sensibility without loosing specificity.
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PMID:[Antigen retrieval by microwave oven with buffer of citric acid]. 799 28

Renal cell carcinoma (RCC) arising in acquired cystic kidney disease (ACKD) is considered to be a tumor of low malignant potential, compared with classic RCC. The aim of the present study was to identify any significant differences in the antigenic profiles or tumor cell proliferative activity of ACKD-associated RCC and classic RCC that might be responsible for differences in their biologic behavior. We studied the immunohistochemical profiles and proliferative activity of 12 classic RCCs and 5 ACKD-associated RCCs with markers of proximal tubules (Leu M1, alpha-1 antitrypsin, CAM 5.2), markers of distal tubules (Arachis hypogaea lectin, AE1/AE3, epithelial membrane antigen [EMAJ, CAM 5.2), vimentin, and proliferating cell nuclear antigen (PCNA). We performed proliferation analysis with the CAS 200 image analysis system. For each case, 8 to 20 fields of tumor tissue in the areas of maximal PCNA staining were quantitated, and the percentage of PCNA-positive nuclear area for each individual tumor was calculated. All of the five ACKD-associated RCCs expressed AE1/AE3, EMA, and CAM 5.2 in more than 50% of the tumor cells. Arachis hypogaea lectin was significantly expressed in three of the five ACKD-associated RCCs. Leu M1 and alpha-1 antitrypsin reacted with fewer than 10% of the tumor cells in all of the five ACKD-associated RCCs. In contrast, the 12 classic RCCs showed expression of CAM 5.2 in 11 cases, alpha-1 antitrypsin in 10 cases, Leu M1 in 9, EMA in 8, and AE1/AE3 in 3 cases in more than 50% of the tumor cells and a totally negative reaction with Arachis hypogaea lectin in 8 cases, EMA in 4, AE1/AE3 in 4, and vimentin in 5 cases. Although coexpression of proximal and distal tubule markers was seen in some cases of RCC in either category, there was uniform and strong staining for distal tubule markers in ACKD-associated RCC and for proximal tubule markers in classic RCC. The mean percentage of PCNA-positive nuclear area for the ACKD-associated RCCs (2.41%) was significantly (P < .05) less than that of the classic RCCs (21.42%). The differences in expression of proximal and distal tubule markers and proliferative activity might be responsible for the differences in the biologic behavior of ACKD-associated RCC and classic RCC.
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PMID:Image analysis of proliferating cell nuclear antigen expression and immunohistochemical profiles in renal cell carcinoma associated with acquired cystic kidney disease: comparison with classic renal cell carcinoma. 957 84

Although no animal is a perfect skin model for the study of toxicological and therapeutic agents, structurally the pig may be superior to even non-human primates. Because our work involves effects of toxicological and therapeutic agents on the skin, we wanted to identify stains which may prove useful as well as determine cross-reactivity of some newer antihuman antibodies. We performed a battery of formalin-fixed skin from weanling pigs and minipigs. The battery of antibodies included LCA, CD3, OPD-4, CD34, UCHL-1, L-26, KP-1, MAC-387, Factor XIIIa, Leu-7, S-100 protein, HMB-45, GFAP, synaptophysin, neurofilament protein, ubiquitin, vimentin, type IV collagen, laminin, fibronectin, Factor VIII related antigen, Desmin-M, smooth muscle actin, cytokeratin 7, cytokeratin 20, AEI/AE3, CAM 5.2, EMA, GCDFP, Ki-67, and PCNA. Immunohistochemical stains for CD3, Leu-7, S-100 protein, type IV collagen, laminin, Factor VIII related antigen, GFAP, synaptophysin, neurofilament protein, ubiquitin, smooth muscle actin, vimentin, Desmin-M, cytokeratin 7, cytokeratin 20, AE1/AE3, CAM 5.2, Ki-67 and PCNA showed consistent cross-reactivity. In formalin-fixed tissue, only antibodies to lymphoreticular cells showed poor cross-reactivity. A high percentage of the remaining antibodies did show good cross-reactivity but with some interesting similarities and differences in specificity.
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PMID:Sensitivity of cross-reacting antihuman antibodies in formalin-fixed porcine skin: including antibodies to proliferation antigens and cytokeratins with specificity in the skin. 974 58

The main components of an unusual form of lung tumor were osteoclast-like multinucleated giant cells and mononuclear stromal cells. Besides, scattered islands of moderately differentiated squamous cells also appeared. Both the mononuclear and the osteoclast-like giant cells reacted with antibodies against CD68 and vimentin, but did not react with antibodies against cytokeratin, EMA and CEA, or lysozyme and a-1-antitrypsin. The p53 and PCNA antigens were positive only in mononuclear cells and not the osteoclast-like giant cells, suggesting that mononuclear cells represent proliferating elements with histiocytic differentiation while osteoclast-like giant cells are stromal, presumably reactive components of the tumor.
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PMID:Osteoclastoma-like Giant Cell Tumor of the Lung. 1117 92

Serous adenocarcinoma of the endocervix is a rare carcinoma similar to the serous carcinoma of the ovary and the endometrium. We report a case of a 63-year-old woman with papillary serous adenocarcinoma arising within the endocervix, describing the clinical presentation and the morphologic characteristics of this rare neoplasm. A detailed immunohistochemical analysis on the expression of low- and high-molecular weight cytokeratins (AE1 and AE3), EMA, CEA, vimentin, B72.3, nm23, estrogen and progesterone receptors, LeuM1 (CD15), p53, Ki-67 antigen, and PCNA by tumor cells has also been carried out, which to our knowledge has not been previously reported.
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PMID:Papillary serous adenocarcinoma of the endocervix: A rare neoplasm. Immunohistochemical profile. 1124 Jun 96

A case of epithelial-myoepithelial carcinoma of the parotid gland harboring p53 mutation is reported. The tumor removed from a 67-year-old Japanese female was composed of an organoid biphasic population of cells: inner dark epithelial cells were surrounded by clear myoepithelial cells. The cells were immunopositive for EMA and smooth muscle actin, respectively. Some of the epithelial cells formed solid nests. Immunostaining for proliferating cell nuclear antigen (PCNA) resulted in a higher percentage of labeled cells in the solid epithelial region than in the region with the more general biphasic pattern. Genetic analysis, including polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and nucleotide sequencing, revealed a mutation in codon 207 (aspartic acid to glycine) of the p53 tumor-suppressor gene. To our knowledge, this is the first report of a mutation in the p53 gene in an epithelial-myoepithelial carcinoma of the salivary gland.
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PMID:Epithelial-myoepithelial carcinoma harboring p53 mutation. 1146 4

The ThinPrep Processor is gaining popularity in both gynecologic and nongynecologic cytologic samples, including effusion specimens. We compared immunocytochemical results on ThinPrep and cell-block preparations from the same effusion specimen with antibodies commonly used in effusion cytopathology. Samples from 17 reactive effusions and 79 effusions with metastatic adenocarcinomas were each prepared as monolayer ThinPreps and formalin-fixed, paraffin-embedded cell blocks. All slides were immunostained with antibodies against intermediate filaments (cytokeratins 8 and 18, and vimentin), cytoplasmic or membrane proteins (EMA, polyclonal CEA, B72.3, and BerEP4), and nuclear antigens (Ki67, PCNA, and p53), using the avidin-biotin procedure. ThinPrep and cell-block slides were stained simultaneously, using identical protocols. Both preparations showed similar results with respect to frequency of positivity, intensity, and distribution of stain for all nonnuclear markers tested. However, for the three nuclear markers Ki67, PCNA, and p53, the frequency and intensity of reaction with ThinPrep were significantly lower than with the cell-block preparation, particularly in malignant effusions. These findings suggest that immunocytochemical results obtained with ThinPrep match those of cell block for most markers tested. However, cell-block preparation are superior to ThinPrep for nuclear markers (Ki67, PCNA, and p53).
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PMID:Immunocytochemistry of serous effusion specimens: a comparison of ThinPrep vs cell block. 1250 74

Hypoxic stress induces apoptosis of hippocampal CA1 neurons while selectively sparing those in CA2-3. Proliferation and differentiation of local stem cells may potentially replace lost neurons. We examined MAP kinase signaling regulation of these dual responses. Rat organotypic hippocampal cultures were exposed to hypoxia for up to 6 h followed by reoxygenation. JNKs and ERKs were maximally activated by 4 h, returning approximately to basal levels by 6 h. Apoptosis of CA1 neurons was maximal by 6-h hypoxia, although JNK activation had returned to basal levels. A neuroprotective protein, JNK-interacting protein 1 (JIP1), an inhibitor of JNK-mediated apoptosis, was reduced by 6-h hypoxia and markedly decreased by 24-h reoxygenation in CA1 neurons as was DENN/MADD, which also modulates JNK-mediated cell death. A second peak of ERK1 activation occurred at 24-h reoxygenation and declined to control levels by 48 h. Stem cells were detected by antinestin and cell proliferation confirmed with anti-PCNA immunohistochemistry and BrdU incorporation. With U0126, an inhibitor of ERK activation, BrdU labeling was strikingly reduced implicating ERKs in the proliferation response. Antidoublecortin (DCX), which detects neural progenitor cells, colabeled a subset of BrdU-positive cells that extended from the dentate granule neurons into CA1. Astrocytes were colabeled with BrdU. Thus, hypoxia concurrently triggered both JNK and ERK signaling, and with reoxygenation, ERK1 activation and stem cell proliferation followed by neuronal progenitor cell differentiation and targeted migration to the site of pyramidal neuronal loss.
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PMID:Neurogenesis response to hypoxia-induced cell death: map kinase signal transduction mechanisms. 1532 27

The present immunohistochemical study was carried out on ten cases of ovarian tumours diagnosed with usual staining as undifferentiated ovarian carcinomas. A panel of antibodies was chosen in order to confirm the epithelial origin of these tumours and to eliminate some possible ovarian metastasis. The cytokeratin AE1/AE3, EMA and BerEP4 positivity supported their epithelial origin even if thirty per cent of the cases co-expressed cytokeratin and vimentin. Even if there is not a specific marker to confirm the ovarian origin of the tumours, the CA125 and CEA positivity suggested that these carcinomas might represent a serous or a mucinous dedifferentiation. Associated with these antibodies, the calretinin, CK7 and CK20 stainings allowed the separation of these tumours from peritoneal mesotheliomas with ovarian extension and from ovarian metastasis originating in the gastrointestinal tract. The evaluation of the PCNA labelling index confirms the high degree of cell proliferation and the aggressiveness of these tumours.
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PMID:Value of immunohistochemistry in confirming undifferentiated ovarian carcinomas. 1584 87


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