Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Tissue Fixation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed1992

Copper,zinc superoxide dismutase is primarily a cytosolic protein in human cells.

The intracellular localization of human copper,zinc superoxide dismutase (Cu,Zn-SOD; superoxide:superoxide oxidoreductase, EC 1.15.1.1) was evaluated by using EM immunocytochemistry and both isolated human cell lines and human tissues. Eight monoclonal antibodies raised against either native or recombinant human Cu,Zn-SOD and two polyclonal antibodies raised against either native or recombinant human Cu,Zn-SOD were used. Fixation with 2% paraformaldehyde/0.2% glutaraldehyde was found necessary to preserve normal distribution of the protein. Monoclonal antibodies were less effective than polyclonal antibodies in recognizing the antigen after adequate fixation of tissue. Cu,Zn-SOD was found widely distributed in the cell cytosol and in the cell nucleus, consistent with it being a soluble cytosolic protein. Mitochondria and secretory compartments did not label for this protein. In human cells, peroxisomes showed a labeling density slightly less than that of cytoplasm.

Aged↗
PubMed2005

Morphology of the fetal rat testis preserved in different fixatives.

Histopathological examination of the testes of exposed fetuses and neonates is important in assessing the developmental effects of environmental toxins, including sex hormone modulators. Modified Davidson's fluid (mDF) has been suggested as a superior substitute for Bouin's fluid for fixation of adult animal testes. We compared the morphology of fetal rat testes stained with hematoxylin and eosin (H&E) or immunochemically after fixation in 10% neutral buffered formalin (NBF), Bouin's fluid, or mDF. Fixation in mDF resulted in more sharply defined nuclear detail and better preservation of cellular cytoplasm on H&E-stained sections of rat testes on gestation day 19. Use of Bouin's fluid did not allow satisfactory detection of apoptotic cells by fluorescent terminal deoxynucleotide transferase-mediated deoxy-UTP nick labeling. Staining with the immunoperoxidase system and the conventional chromogen diaminobenzidine tetrahydrochloride to visualize 5-bromo-2-deoxyuridine-positive cells demonstrated that the number of positive nuclei and intensity of staining were similar with all 3 fixatives. Immunostaining for cytoskeletal protein vimentin was more intense and provided better details of the Sertoli cell cytoplasm with formalin fixation than with mDF. Our study demonstrates that fixation in mDF provided better morphologic detail in the fetal rat testis compared with 10% NBF and Bouin's fluid and illustrates the importance of establishing the correct fixation conditions for each immunostaining protocol.

Animals↗
PubMed1998

Optimized fixation and storage conditions for FISH analysis of single-cell suspensions.

In our protocol to isolate and identify fetal cells in maternal peripheral blood, antibody (Ab)-stained cells are preserved with paraformaldehyde (PF) before batch flow cytometric sorting. However, PF fixation compromises the quality of subsequent interphase fluorescence in situ hybridization (FISH). We therefore examined the effect of PF concentrations and storage time in phosphate-buffered saline (PBS) on the quality of FISH signals. Cells were analyzed for changes in light scatter, morphology, and accessibility of target cell DNA. Fixation in 3% PF for 1 hr was ideal for both flow cytometry and subsequent FISH detection. However, beyond 10 days of storage, FISH quality deteriorated. (J Histochem Cytochem 46:971-973, 1998)

Buffers↗
PubMed1986

Keratin protein immunohistochemistry in surgical pathology practice.

Keratin protein immunohistochemistry is a powerful diagnostic tool whose role has already been firmly established in many surgical pathology laboratories. Recent studies of the biology of keratin proteins have defined the heterogeneity of keratin protein expression among various epithelial tissues and their tumors and provide the basis for understanding the immunoreactivity of epithelial tumors with various keratin antibodies. Successful execution of the procedure requires attention to technical details such as the fixation of tissue, use of proteolytic enzymes such as trypsin for formalin-fixed tissues, and the choice of the appropriate antibody and controls. Broadly reactive polyclonal and monoclonal antibodies to keratins have been remarkably useful in identifying poorly differentiated and undifferentiated carcinomas. Monoclonal antibodies of restricted specificity and monospecific antibodies to keratin are under development and may prove helpful in defining the organ of origin of metastatic carcinomas. Keratin protein immunohistochemistry supplements existing information used by pathologists in diagnosis, and the immunohistochemical results should be interpreted in the light of the clinical findings, gross and microscopic pathology, and the results of any other special studies.

Animals↗
PubMed1994

Evaluation of biomarkers in breast and prostate cancer.

p53, p185erbB-2, and epidermal growth factor (EGF) receptor are well-characterized biomarkers in invasive adenocarcinoma of the breast and in ductal carcinoma in situ. erbB-2 Protein (p185erbB-2) must be identified clearly on cytoplasmic membranes while cytoplasmic expression is ignored for breast cancers to be classified as overexpressing p185erbB-2. For p53, nuclear staining and the percent positive cells are considered, but rules for "cut-offs" are not defined. Evaluation criteria for biomarkers in prostate cancer are preliminary and the "rules" may not be the same as for breast cancer. Because the initial methods of fixation and tissue processing can change both the pattern and intensity of immunohistochemical identification of specific antigens and localization of receptors may change after the receptor-ligand interactions, we evaluated the effects of fixation both on the immunolocalization and intensity of expression of p53, p185erbB-2, and EGF receptor. We also studied the patterns of p185erbB-2 and p53 expression in a series of breast cancers evaluated concomitantly with a group of prostate cancers. Our results confirm that p53 mutations are common in breast cancer and that there is strong expression of p185erbB-2 on the membranes of a subset of breast cancers. The patterns of staining for both p53 and p185erbB-2 are different in prostate and breast cancers. A much lower proportion of prostate tumors than breast tumors have more than 10% of tumor cells with detectable nuclear p53 protein, but this proportion increases markedly in metastatic tumors or in primary stage D prostate cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed2003

Evaluation of testicular toxicology: a synopsis and discussion of the recommendations proposed by the Society of Toxicologic Pathology.

BACKGROUND: Detection of chemically induced effects on male fertility and on testicular spermatogenesis in particular, has become of increasing concern. More stringent regulatory guidelines, introduced by ICH, EPA and OECD (Table 1) have raised the awareness of toxicologists and pathologists for the need to conduct sensitive and careful evaluation of the male reproductive tract for potential toxic effects of administered compounds. With it has come confusion and in many cases, inappropriate procedures, often based on misunderstanding of what is required and on inadequate understanding of spermatogenesis. This article summarizes and discusses the main recommendations recently proposed by the Society of Toxicologic Pathology on recommended approaches for the evaluation of testicular and epididymal toxicity [Lanning LL, Creasy DM, Chapin RE, Mann PC, Barlow NJ, Regan KS, Goodman DG. Toxicologic Pathology 30:518-531, 2002]. The major recommendations are: Use sexually mature animals to evaluate effects on spermatogenesis. Sample left and right testes and epididymides and record organ weights. Use modified Davidson's fixative to fix testes from all species from studies of 13 wks duration and less. Examine transverse sections of the testes (including part of the rete), and longitudinal sections of the epididymides. Embed tissues in paraffin wax. For rodent studies up to 28 days, examine periodic acid-Schiff's-hematoxylin stained sections. For all other studies examine hematoxylin and eosin stained sections. Microscopic evaluation of the testis should be a qualitative evaluation carried out with an awareness of the spermatogenic cycle. Quantitative procedures are inappropriate for screening studies. Nomenclature and grading of findings for spermatogenic disturbances will vary on a case by case basis.

Animals↗
PubMed1994

Different reactivity with monoclonal anti-tubulin antibodies between native and fixed mitotic microtubules in sea urchin eggs.

The effect on fixation on the reactivities of mitotic microtubules with monoclonal anti-tubulin antibodies was investigated by the indirect immunofluorescence procedure. All of the seven antibodies used intensely stained mitotic microtubules in sea urchin eggs lysed and fixed with methanol at -20 degrees C, whereas only two of them stained the stabilized microtubules in the lysed eggs before the fixation. The other five did not stain the mitotic microtubules even after microtubule components other than tubulin were removed by treating the lysed eggs with 0.4 M KCl solution containing taxol. These results exclude the possibility that the fixation affects proteins, which interact with microtubules including microtubule-associated proteins (MAPs) and interfere with the binding of monoclonal antibodies with tubulin, and strongly suggest that the fixation directly affects the three-dimensional conformation of tubulin. Furthermore, microinjection of these antibodies indicated the results as follows [combining the results reported previously; Oka et al., 1990: Cell Struct. Funct. 15: 373-378]: The antibodies which stained mitotic microtubules stabilized in the lysed eggs induced disassembly of native mitotic microtubules in the living eggs, but those which did not stain the stabilized microtubules did not disassemble the native microtubules. From these results, it is suggested that the monoclonal antibodies which stain microtubules in the eggs lysed but not fixed are useful for microinjection experiments.

Animals↗
PubMed2003

Effective chemical preservation of morphology of urinary erythrocytes.

Between 2 and 4 h after miction the morphology of urinary erythrocytes has changed, clouding the distinction between glomerular and non-glomerular bleeding in pediatric patients. Glomerular bleeding is characterized by microscopically visible alteration in urinary erythrocytes due to glomerular disease. Fixation by Cellfix, a formaldehyde-based fixative, allows the preservation of the morphology for at least 24 h and can be recommended for clinical practice. In our experience, thiomersal was not effective for preservation of the morphology of erythrocytes.

Acanthocytes↗
PubMed1991

Microwave-accelerated fixation and lacZ activity staining of testicular cells in transgenic mice.

Microwave energy has been used in conjunction with glutaraldehyde to rapidly fix testicular samples of transgenic mice (whole tubules, individual cells, and cryosections) as a preparation for histochemical bacterial beta-galactosidase activity staining. The results demonstrate that the microwave-enhanced aldehyde fixation step is a convenient and simple adaptation for routine analyses, with almost no artifactual consequences or gross distortions in morphology at the microscopic level. The entire procedure (from sacrificing the animal to microscopic observation of the blue spermatogenic cells) can be completed in 1 h.

Animals↗
PubMed2002

Histochemical localisation of carboxylesterase activity in rat and mouse oral cavity mucosa.

Vinyl acetate (VA) is widely used within the chemical industry, in the manufacture of polyvinyl alcohol, and as polyvinyl acetate emulsions in latex paints, adhesives, paper and paper board coatings. Chronic oral exposure of rodents to high concentrations of VA induces tumours within the oral cavity. Carboxylesterase-dependent hydrolysis of VA is thought to be critical in the development of nasal tumours following inhalation exposure of animals to VA. Therefore, carboxylesterase activity was determined histochemically in the oral cavities of male F344 rats and BDF mice in order to explore the potential role of carboxylesterase-dependent hydrolysis of VA in the development of oral tumours. Following fixation in 10% neutral buffered formalin heads were decalcified in neutral saturated EDTA, embedded in resin, sectioned at six levels (three each for the upper and lower jaws), and carboxylesterase activity revealed in the tissue using alpha-naphthyl butyrate as substrate. The localisation of carboxylesterase activity in freshly dissected rat oral tissue was compared to that of the resin sections and found to be identical, thus validating the decalcification process. A similar pattern of carboxylesterase activity was observed for the two species. Staining was low in areas surrounding the teeth, and medium/high in the buccal mucosa, the central/posterior upper palate and those regions of the lower jaw not proximal to the teeth. In general the intensity of staining was greater in sections from the rat compared to those from the mouse. By comparison, carboxylesterase activity was considerably higher in mouse nasal olfactory epithelium than in any of the oral tissues. Thus the mucosa of the oral cavity has the potential to hydrolyse VA to its metabolites, acetic acid and acetaldehyde, and the presence of carboxylesterases at this site is consistent with, and may be an important determining factor in, the development of oral cavity tumours following exposure to VA.

Animals↗
PubMed1998

Intrapulmonary metastasis of lung cancer: soft x-ray investigation of inflated and fixed lung.

BACKGROUND: Intrapulmonary metastasis (IPM) of lung cancer is thought to be an important factor influencing patient prognosis. It is not easy to detect a small IPM by preoperative examination and sometimes even by postoperative pathologic investigation. We applied soft x-ray investigation to inflated and fixed lungs for the detection of IPM. STUDY DESIGN: From 1990 to 1992, 75 patients with lung cancer who had no metastatic lesions on preoperative whole CT, MRI, and technetium-99m bone scintigram examinations underwent lung resection. The resected lungs were fixed in an inflated condition, sliced at the corresponding CT levels into 10-mm-thick sections, and submitted for soft x-ray examination. When an accessory nodular shadow(s) was detected on the soft x-ray images, the size of the nodule and its distance from the primary tumor were measured. RESULTS: In 23 of the 75 patients, accessory nodular shadows were detected on the soft x-ray images. Six nodules in 6 patients proved to be IPM, 2 of which were also detected by postoperative macroscopic examination. Another 2 microscopic IPM were found only by postoperative pathologic examination. The total detection rate of IPM was 10.7% (8 of 75 patients) in this series. The detection rate of IPM at our institute was 5.4% before this study (1979 to 1989). The mean diameter of the IPM detected by the soft x-ray method was 2.8 +/- 1.5 mm, and this was significantly smaller than that of the macroscopically detected nodules (7.2 +/- 3.2 mm). CONCLUSIONS: Our data show that soft x-ray investigation is an effective procedure to detect relatively small intrapulmonary metastatic nodules and will contribute to precise postoperative staging of patients with lung cancer.

Adenocarcinoma↗
PubMed2000

Effect of fixation and epitope retrieval on BrdU indices in mammary carcinomas.

Studies in which 5-bromo-2'-deoxyuridine (BrdU) is used to quantify rates of cell proliferation are conducted prospectively. Therefore, the opportunity exists to select conditions that optimize detection of the BrdU epitope. The objective of this study was to quantify the extent to which the BrdU epitope was masked by formalin vs methacarn fixation in the assessment of cell proliferation. Mammary carcinomas from animals pulse-labeled with BrdU were trisected. A portion was frozen and the remaining two portions were fixed in 10% neutral buffered formalin or methacarn for 24 hr, processed, embedded in paraffin, and sections stained for incorporated BrdU using a peroxidase immunohistochemical staining technique. Antigen retrieval techniques also were applied to formalin-fixed sections. Fixation in methacarn gave the highest labeling index (16.4%), which was comparable to that observed in unfixed frozen sections (17.5%). Formalin fixation alone dramatically suppressed the labeling index (0.3%), which was only partially recovered using various antigen retrieval techniques (2.1-8.1%). Methacarn fixation is recommended for prospective studies in which BrdU detection is planned because of the quantitative recovery of epitope and the simplicity of the approach.

Acetic Acid↗
PubMed1997

Surface ultrastructure of intact and in situ chlorhexidine-treated human buccal cells. A method for scanning electron microscopy.

Air-dried and ethanol-fixed buccal epithelial cell smears from five subjects were observed by scanning electron microscopy. The mucous pellicle was precipitated as a smooth haze covering the cells, and outlines of bacteria were found embedded within it. Rinsing the preparations under running water gradually diminished the mucous pellicle but not the cell-adherent bacteria. A more complete dissolution of the pellicle was accomplished by washing the buccal epithelial cells before smearing. After a chlorhexidine mouthrinse the buccal cells appeared distorted, with only a few adherent bacteria. Three days after the rinsing, the denatured appearance still persisted on many cells, however, simultaneously with the emergence of undenatured epithelial cells with adherent bacteria. The method introduced in this study is useful to investigate the bacteria-mucus-epithelial cell interactions. A possible mode of antibacterial activity of chlorhexidine in vivo may be that it destroys bacterial adhesins. The substantivity of chlorhexidine in the oral cavity may be linked to the turnover rate of the oral epithelial cells.

Adhesins, Bacterial↗
PubMed1999

Glutathione levels in primary glial cultures: monochlorobimane provides evidence of cell type-specific distribution.

Because glutathione (GSH) levels in glia play an important role in cellular defense against oxidative and nitrosative stress, the present study was designed to study GSH levels in the primary glial cell cultures. Here we used fluorescence microscopy and spectroscopy with monochlorobimane for measurement of intracellular glutathione content. Monochlorobimane showed high specificity for GSH with very little binding to protein sulphydryls as ascertained from the low fluorescence intensity of the protein fraction of the cells as well as from the low fluorescence of the GSH-depleted cells. The formation of the monochlorobimane-glutathione conjugate was observed to be enzymatically catalyzed as seen from its higher rate of formation in the presence of cell homogenate. A monochlorobimane concentration of 60 microM was used for conjugation of cellular GSH; at higher mBCl concentrations there was no appreciable increase in fluorescence. Therefore, cultures were treated with 60 microM mBCl for an incubation time of 20 min (beyond this time, export of the bimane-glutathione adduct was significantly large) and examined by fluorescence microscopy. This adduct could be fixed with a mixture of paraformaldehyde and glutaraldehyde, and excellent fixation was observed with 4% paraformaldehyde and 0.2% glutaraldehyde. Analysis of the fluorescence images revealed differences in fluorescence intensity between astro- and microglial cells, which were identified by glial fibrilliary acidic protein and OX42 staining, respectively. Microglial cells isolated from primary glial cultures were found to have higher GSH content than astrocytes. Biochemical determination of GSH levels in microglia isolated from primary glial cultures corroborated this fact. From our findings it seems that owing to the greater intracellular concentration of reactive oxygen and nitrogen species to which microglia are subjected, especially under conditions of inflammation, this cell type is fortified with higher GSH levels as a means to combat oxidative and nitrosative stress.

Animals↗
PubMed2001

Routine formaldehyde fixation irreversibly reduces immunoreactivity of Bcl-2 in the nuclear compartment of breast cancer cells, but not in the cytoplasm.

Bcl-2 and Bax belong to a family of proteins involved in apoptosis regulation and are believed to reside in the cellular cytoplasm. The authors recently reported interphase nuclear localization of both proteins after immunofluorescence staining of formaldehyde- and methanol-fixed human and rodent cell monolayers. In addition, the authors' data confirmed earlier reports on Bcl-2 immunoreactivity of mitotic chromosomes in human cells. In their experience, nuclear or mitotic staining of Bcl-2, in contrast with cytoplasmic Bcl-2 immunoreactivity, is rarely observed in formaldehyde-fixed, paraffin-embedded breast cancer specimens. Therefore, the authors wondered if nuclear and mitotic Bcl-2 immunoreactivity could be irreversibly reduced by certain fixation procedures, including formaldehyde fixation. Here the authors investigated the effects of various routinely used fixation protocols and antigen retrieval techniques on Bcl-2 and Bax immunoreactivity in monolayers of MCF-7 human breast cancer cells. Whereas nuclear and mitotic immunoreactivity for Bcl-2 was clearly present after formaldehyde and methanol fixation, it was completely absent in cells fixed in acetone, methanol, or formaldehyde alone. In addition, it was found that in particular nuclear and mitotic Bcl-2, and to a lesser extent cytoplasmic Bcl-2 immunoreactivity, decreased after prolonged formaldehyde fixation, whereas Bax immunoreactivity diminished only slightly. Heat-mediated antigen retrieval after prolonged formaldehyde fixation elevated cytoplasmic, but not nuclear and mitotic, Bcl-2 immunoreactivity.

Animals↗
PubMed2006

Rabies in apparently healthy dogs: histological and immunohistochemical studies.

A slaughterhouse survey for rabies virus infection among apparently healthy dogs slaughtered for human consumption was carried out in Maiduguri, Nigeria. Formalin-fixed and paraffin-embedded tissues (salivary gland, hippocampus, cerebrum, medulla, and trigeminal ganglion) were obtained from a total of 52 head samples from slaughtered dogs. The paraffin-embedded tissues were analysed histologically using the haematoxylin and eosin (H&E) method for the presence of inclusion bodies and histochemically by streptavidin - biotin peroxidase staining method for detection of rabies virus antigens. Prior to fixation of tissue, impression smears were made from the hippocampus and stained by Sellers method to detect the presence of Negri bodies. Rabies virus antigen was detected in tissues from 16 (31% ) of the 52 dog heads. Histological diagnosis by H&E revealed various degrees of inflammatory changes in the salivary gland and brain tissues with few Negri bodies from 10 (19% ) of the 52 dogs tested. However, all tissues positive by H&E were also positive by immunoperoxidase method using the streptavidin- biotin peroxidase staining procedure. Ten (30% ) of the 33 male and 6 (32% ) of the 19 female dogs tested were positive for presence of rabies virus antigen. There was no significant difference between sexes in relation to rabies virus infection. The application of immunoperoxidase staining technique in the localization of rabies virus antigen in the submaxillary salivary gland was more sensitive (based on the relative number of positive tissues) when compared with the application of the method to other organs. Apparently healthy dogs may be important in the epidemiology and control of rabies in this environment.

Animals↗