Gingival carcinogenesis in the hamster, using tissue adhesives for circinogen fixation.
Explore the source record for details and available documents.
Acrylates↗
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.
Polymerase chain reaction amplifying DNA coding for species-specific rRNA of Mycobacterium leprae.
The sensitivity of the polymerase chain reaction (PCR) on the DNA coding for the species-specific fragment of 16S rRNA of Mycobacterium leprae studied on mouse foot pad harvests and human skin biopsies varies widely between 1 and 3 x 10(4) organisms. This is probably the result of variations in the proportions of organisms with sufficiently intact DNA suitable for PCR. Preserving human skin biopsies for 3 weeks at an ambient temperature even after boiling for 6 minutes gives rise to a 10-fold decrease in sensitivity. Fixation of tissues in formol 10% or Lowy fixative or preserving in Dubos OAA broth is very harmful to the PCR, mainly due to the enhancement of an inhibitory effect on the PCR reaction. For preservation, the best choice at the moment seems to be alcohol 70%. Sample preparation of five cycles of freeze-boiling is simple and generally more efficient than proteinase K treatment and DNA extraction.
Animals↗
Staining in normal and ischemic human myocardium. A study of myoglobin, IgG, glycogen, and diastase-PAS.
Using the indirect immunofluorescence technique, we studied the distribution of myoglobin in normal and ischemic human myocardium obtained at autopsy and at surgery. Glycogen, diastase-PAS staining of the sarcoplasm, and IgG were also studied and compared with the structure of the lesions and the distribution of myoglobin. The surgical material we used was largely free of autolysis and was the most satisfactory. Prolonged fixation of tissues in formaldehyde solution or perfusion fixation of autopsy specimens both proved to be unsatisfactory as myoglobin was absent from the myocardium. This loss presumably represents diffusion of myoglobin due to autolysis and the method of fixation. Another group of autopsy specimens that was briefly fixed by immersion in formaldehyde solution prior to processing was more satisfactory. Although they showed some extracellular diffusion of myoglobin, the autolyzed normal areas could still be clearly differentiated from the autolyzed ischemic areas.
Amylases↗
[Most efficient methods of cryodestruction of malignant neoplasms].
Some peculiarities of the procedure for cryodestruction of neoplasms of various sites developed by the authors are considered. The regularities of variation in the adhesion of cryoapplicator to tissues on gradual cooling are discussed. The report is concerned with cryogenic procedures designed to ensure destruction of tumor cells and to prevent tumor cell dissemination in the course of surgical intervention. The cryogenic installation Penguin was used. Such effects as applicator's adhesion to tissue and its freezing-induced fixation in tissue were employed. Thawing period was prolonged with cryoapplicator still in contact with tissue. Tumor tissue adjacent to normal one was allowed to thaw to 0 degrees C.
Animals↗
Ionomeric cement--a bone glue for device fixation.
Ionocap, an ionomeric cement, is a new bone replacement material. Its generic name is polymaleinate ionomer, and it is an inert standardized biomaterial which is offered in a two component system. Since 1988 the ionomeric cement has been evaluated clinically in different situations. Its unique properties of biocompatibility, biostability and permanent adherence to bone make this new material very useful in head and neck surgery.
Animals↗
Formation of replica of root canal morphology of maxillary first premolars. A technique.
Various methods have been used to study the root canal morphology of human teeth. The purpose of this study was to develop a technique for the formation of a resin replica of the root canal morphology of maxillary first premolars. 30 recently extracted maxillary first premolars were used for the study. An occlusal access cavity was prepared and the teeth placed in 5% sodium hypochlorite solution to dissolve the pulp remnants. The teeth were then rinsed in water. A two-part resin system was then introduced into the root canal through the access cavity opening. Subsequent to curing the resin using a specific curing cycle the specimens were put in 20% hydrochloric acid. This facilitated the dissolution of the tooth and the retrieval of the resin replica of the root canal. The different types of root canal morphology observed are discussed. The relevance and utility of the resin models and further possibilities in this field are discussed.
Adolescent↗
[Metallic elements in tissues surrounding internal rigid fixation (IRF) devices].
BACKGROUND: Plates and other devices made by several alloys have been introduced to reach the stability of bone fractured fragments. Elements constituting alloys could be detected especially in organs, yet also in local tissues. Aim of the present study is the analysis of tissues surrounding IRF devices analyzing the morphology of released particles and studying the behavior of adjacent tissues to check metallic elements diffusion. METHODS: Biopsies were retrieved from 18 patients, aged 20 to 76 years. The patients received IRF by plates, screws and grids from 4 months to 9 years. They were divided into five groups according to the local phlogistic degree. Ordinary light microscopy, scanning electron microscopy and X-ray microprobe analysis (EDS system) was used to perform morphological investigations and identification of metal particles and elements. RESULTS: Metal particles or elements arising from plates, screws or grid may undergo tissular diffusion and cellular uptake. Not only Chromium, Iron or Aluminium but also Titanium may be easily released from devices and engulfed in tissues. In particular Titanium diffusion is evident in fibrous tissue surrounding IRF devices. Aluminium appears to be particularly accumulated in a persistent way in fibrous tissues and shows a characteristic embedding pattern in lamellar bone. CONCLUSIONS: The degree of local phlogosis appears to be strictly correlated to metallosis. Chromium, Iron, Aluminium and also Titanium, even if at different degree, give rise to phlogistic effects. Metallosis and phlogosis can produce a cascade process in which they are both the cause and the effect at the same time. The abundant release of Titanium, which does not normally produce clinical phlogosis as i.e. Aluminium, should be worthy of further investigations on its cellular effects.
Adult↗
Detection of the Ki-67 antigen in fixed and wax-embedded sections with the monoclonal antibody MIB1.
Novel antibodies have been generated by immunizing with bacterially expressed fragments of the repetitive motif of the Ki-67 gene. One such antibody, MIB1, recognizes a fixation and embedding resistant epitope on the Ki-67 protein if sections are previously microwaved in a citrate buffer. We have investigated the utility of this antibody as a marker of cell proliferation in archival material. The microwave technique is simple but requires careful monitoring since different tissues and fixatives require different irradiation times. Strong nuclear immunoreactivity was detected with all fixatives studied. Cytoplasmic staining was not identified. In a wide range of normal tissues the distribution and number of MIB1 immunoreactive cells matched that of cryostat sections stained with Ki-67. In nude mouse xenografts in which the growth fraction had been defined using a fraction of labelled mitosis method, the labelling index with MIB1 matched that previously determined for Ki-67 and correlated well with the growth fraction. Other markers of proliferation (e.g. proliferating cell nuclear antigen) have been shown to be expressed in DNA repair, thus we investigated expression of MIB1 immunoreactivity in situations of DNA repair in vivo--ultraviolet irradiated human skin. MIB1 staining correlated with semi-conservative DNA synthesis rather than excision repair DNA synthesis. Finally, the morphological and cell cycle distribution of MIB1 expression is identical to that of Ki-67. Thus, MIB1 represents a new anti-Ki-67 antibody which appears to be a robust marker of cell proliferation easily applicable to archival material.
Animals↗
Routine use of phenolized formalin in fixation of autopsy brain tissue to reduce risk of inadvertent transmission of Creutzfeldt-Jakob disease.
Explore the source record for details and available documents.
Autopsy↗
Improved fixation of frozen lympho-haemopoietic tissue sections with hexazotized pararosaniline.
In this study, a simple single-step fixation method for frozen tissue sections is introduced using the hexazotized salt of Pararosaniline as preservative agent. Tissue preservation by this method was shown to be superior to the commonly-used fixation with acetone. Fixation with hexazotized Pararosaniline caused a minimal loss of antigenicity as demonstrated using twenty-three monoclonal antibodies directed against lympho-haemopoietic and stromal cells.
Animals↗
Fixation and immunohistochemistry of lymphoid tissue.
Explore the source record for details and available documents.
Animals↗
Cervical tissue shrinkage by formaldehyde fixation, paraffin wax embedding, section cutting and mounting.
To evaluate the efficacy of cryocoagulation as a treatment for cervical intraepithelial neoplasia (C.I.N.), it is necessary to know the maximum depth of the glandular crypts, the maximum crypt involvement by C.I.N. and the extension of the cryolesion, obtained under standardized conditions. In a morphometric study on this subject, one has to take into account the shrinkage of the cervical tissue, caused by processing the tissue for histological examination. In the present study, tissue shrinkage of the cervix in different directions was measured in three separate steps. First shrinkage caused by formalin fixation was determined, second shrinkage caused by dehydration, clearing and paraffin wax embedding and finally that caused by section cutting and mounting. Shrinkage caused by formalin fixation, and by dehydration, clearing and paraffin wax embedding did not differ significantly in the different directions and resulted in an average shrinkage of respectively 2.7% and 12.6% of the original dimensions. The alterations of the dimensions by section cutting and mounting is not a process of shrinkage, but actually a deformation caused by pressure on the tissue during sectioning. Generally the dimension decreases in the cutting direction and increases in the direction perpendicular to it. In the calculation of the total shrinkage these alterations can be neglected, since the changes, although not consistent are small. It follows that in morphometric studies a total shrinkage of about 15% of the original dimensions has to be taken into consideration.
Cervix Uteri↗
The effect of different storage methods on the mechanical properties of trabecular bone.
The effect of different storage methods on the elastic and viscoelastic properties of trabecular bone was examined using non-destructive compression tests to 0.45% specimen strain. There was a 10% decrease in stiffness during the first 24 h post mortem. Storage by freezing or in ethanol for 100 d did not change the stiffness, and neither did several thawing, testing and refreezing sequences. The viscoelastic properties were more sensitive to storage and showed significant although small changes during 100 d of storage. The effect of defatting the specimens was a 30% increase in stiffness and a 50% decrease in viscoelastic energy dissipation.
Adult↗
Proliferating cell nuclear antigen. A marker for cell proliferation in autopsy tissues.
Antibodies to the proliferating cell nuclear antigen allow identification of proliferating cells in fresh tissue specimens using routine immunocytochemical methods. However, the use of such proliferation markers has not been verified for autopsy-derived tissue specimens, in which there is often a significant delay between the time of death and tissue specimen fixation. To assess the reliability of anti-proliferating cell nuclear antigen antibodies to identify proliferating cells in autopsy tissue specimens, an autopsy simulation was performed using fresh monkey and rat tissue specimens. These tissue specimens were kept at room temperature for predetermined numbers of hours before fixation. The proliferation specific staining was most reliable for tissue specimens obtained within 6 hours of death. There was reliable staining of proliferating regions up to 12 hours, although sensitivity was decreased. The only exception was skin, which was able to withstand much longer periods. Quantitative data from monkey spleen white-pulp regions showed 63% of the cells to stain for proliferating cell nuclear antigen when fixed immediately; this decreased to 29% of the cells after 12 hours and only 19% by 18 hours of postmortem simulation. Representative tissue specimens obtained from human autopsy material revealed similar postmortem staining patterns. Rapid procurement and fixation of tissue specimens and the use of control tissue specimens derived from the same autopsy material (eg, lymph node tissue) are recommended. These studies do suggest that anti-proliferating cell nuclear antigen antibodies can be used to identify proliferating cells in human autopsy tissue specimens obtained within approximately 12 hours of death, with some compromise in overall sensitivity.
Animals↗
Antigen retrieval technique utilizing citrate buffer or urea solution for immunohistochemical demonstration of androgen receptor in formalin-fixed paraffin sections.
We developed a staining protocol for demonstration of androgen receptor (AR) in formalin-fixed, paraffin-embedded tissue sections. The method is based on the antigen retrieval microwave (MW) heating technique. Results are compared with different types of enzyme digestion pre-treatments. The strongest immunostaining signal and clearest background were obtained by MW heating of dewaxed paraffin sections in 5% urea or citrate buffer solution (pH 6); pure distilled water gave less consistent results. Enzymatic digestion with pepsin (0.05% in 2 N HCl) for 30 min at room temperature, or trypsin followed by pronase, or pronase digestion alone, also produced enhanced staining of AR in some cases, but there was more nonspecific background, and specific reactivity was less intense. The antigen retrieval MW method can be used to demonstrate AR epitope in prostate tissue after fixation in formalin for as long as 7 days. AR immunolocalization was also compared in frozen and paraffin sections processed from the same specimen of prostate carcinoma tissue and was found to be qualitatively and quantitatively similar. This study also provided new information concerning the basic principles of the antigen retrieval MW method that may be helpful in further development of this technique.
Antigens, Neoplasm↗
Fixation of Thy-1 in nervous tissue for immunohistochemistry: a quantitative assessment of the effect of different fixation conditions upon retention of antigenicity and the cross-linking of Thy-1.
It has proved difficult to obtain good immunohistochemical localization of cell surface antigens in nerve for a number of reasons, prominent among which are problems of fixing this class of molecule without destroying their antigenicity. In the course of developing a fixation procedure suitable for one such antigen. Thy-1, we have quantitatively assessed the effect of different fixation parameters upon the retention of Thy-1 antigenicity and upon the extent of cross-linking of the antigen in the tissue. The former was measured using radioimmunoassays adapted for membrane antigens in fixed tissue, the latter by measuring the proportion of antigen rendered insoluble to the detergent, sodium deoxycholate, and by examining the size of the antigen on sodium dodecyl sulfate--polyacrylamide gels. These approaches demonstrated that minor modifications of the standard vascular perfusion fixation of brain, using both glutaraldehyde and paraformaldehyde, were sufficient to fix the Thy-1 molecule, and at the same time substantially spare its antigenicity. In this study we measured Thy-1 using both a conventional rabbit antiserum and a mouse monoclonal antibody to the Thy-1.1 antigenic determinant. The multiple antigenic determinants recognized by the rabbit antibodies were cumulatively more resistant to fixation than the single antigenic determinant recognized by the monoclonal antibody.
Animals↗
Biochemical, electron microscopic and immunohistological observations of cationic detergent-extracted cells: detection and improved preservation of microextensions and ultramicroextensions.
BACKGROUND: Filopodia, retraction fibers and microvilli, are fragile microextensions of the plasma membrane that are easily damaged by mechanical force during specimen preparation for microscopy. To preserve these structures for electron microscopy glutaraldehyde is generally used, but it often causes antigen masking. By contrast, formaldehyde is generally used for immunofluorescence light microscopy, but few studies have been concerned with the loss of microextensions. RESULTS: We demonstrate in biochemical experiments that cultured cells needed to be kept in 4% formaldehyde for at least 60 min at room temperature or for 20 min at 37 degrees C to irreversibly crosslink most of the polypeptides. Also, fragmentation of fragile microextensions was observed after Triton X-100 extraction depending on concentration and extent of crosslinking. We also report on a novel fixation procedure that includes the cationic detergent dodecyltrimethylammonium chloride (DOTMAC). Treatment of NIH3T3 cells with DOTMAC resulted in complete removal of membrane lipids and in good preservation of the cytoskeleton in microextensions as well as preservation of ultramicroextensions of <0.05 microm in diameter that have not been observed previously unless glutaraldehyde was used. Stress fibers and microextensions of DOTMAC-extracted cells were readily stained with anti-beta-actin antibodies, and antibodies to vinculin and moesin stained focal contacts and microextensions, respectively. CONCLUSIONS: Some microextensions were fragmented by the standard Triton X-100 permeabilization method. By contrast, DOTMAC completely extracted membrane lipids while maintaining the cytoskeleton of microextensions. Thus, DOTMAC treatment may provide a valuable new tool for the reliable visualization of previously undetectable or poorly detectable antigens while preserving the actin cytoskeleton of microextensions.
3T3 Cells↗
[Tissue specificity of testosterone fixation: demonstrated by ultrastructural immunocytochemistry after cryoultramicrotomy].
Testosterone can be detected by immunocytochemistry on ultrathin slices obtained by cryoultramicrotomy. Testosterone detected by this method is likely bound on a binding site having a high affinity. In order to study the tissue specificity of this binding, testosterone was tested in Rat pituitary gland, liver and adrenal glands. Immunoreactive testosterone was detected in the gonadotropic cells of the pituitary gland, in the hepatocytes. Testosterone was not detected by immunocytochemistry in the pituitary cells other than the gonadotropic cells and in the cells of the medulla of adrenal glands. These data testify in favour of tissue specificity of the testosterone binding.
Adrenal Glands↗