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At least 973 records · Page 54Linked to original sources
PubMed1994

A new monoclonal antibody (3A5) that recognises a fixative resistant epitope on tissue macrophages and monocytes.

AIMS: To develop a monoclonal antibody specific for human macrophages in routinely processed material. METHODS: The monoclonal antibody was derived from a mouse popliteal lymph node after subcutaneous immunisation in the footpad with fragments of human spleen depleted of lymphocytes and erythrocytes. RESULTS: 3A5 is a monoclonal antibody reactive with macrophages, monocytes, and histiocytes in routinely processed (formalin fixed, paraffin wax embedded) human tissue specimens. Unlike the well known panmacrophage marker KP1 (CD68), neither dendritic cells (interdigitating cells, Langerhans' cells, and microglia) nor myeloid, lymphoid, or epithelial cells stained with 3A5. CONCLUSION: As the staining pattern of 3A5 is restricted, compared with other macrophage markers and the recognised epitope survives common fixation and embedding procedures, 3A5 is a valuable marker for histiocytes and macrophages in routine diagnostic applications.

Animals↗
PubMed1993

Rapid primary microwave-glutaraldehyde fixation preserves the plasma membrane and intracellular structures of the protozoan Tritrichomonas foetus.

Tritrichomonas foetus, a pathogenic protozoan, was used as a model to analyse microwave-stimulated fixation as a procedure of preparation of biological samples for electron microscopy of thin sections and freeze-fracture replicas. Good preservation of the protozoan structure was achieved by microwave-stimulated fixation and Epon polymerization. The membrane structure, as visualized in freeze-fracture replicas, was well preserved.

Animals↗
PubMed1996

Preservation of the non-rectangular cuticular plate/cell axis angle of outer hair cells.

Motile properties of outer hair cells (OHCs) may contribute to sharp tuning and amplification in the mammalian cochlea. Shape changes of isolated OHCs in response to various physical and chemical influences have been investigated intensively. However, determinations of shape may have been influenced by unanticipated effects of preparation and preservation of the OHCs investigated. Thus, in a first step, lengths of freshly isolated OHCs from the guinea pig cochlea were determined using a video-enhancing magnification system. The cuticular plate/cell axis angle (CP/CA angle) was then measured in native cells and under the influence of potassium chloride and potassium gluconate incubation. To show the influence of glutaraldehyde (GA) fixation on the isolated OHCs, fixative-dependent changes on cell length and CP/CA angle were recorded in native and preincubated OHCs. In these experiments, the cell length of vital isolated OHCs was between 41.5 micrometers, in the basal turn, and 103.7 micrometers, in the apical turn. The average CP/CA angle was 106 degrees +/- 4.2 degrees (n = 324 cells, turns 1-4) with no statistically significant differences for the four turns. Under the influence of potassium chloride, cell length was reduced by 8.1%. Potassium gluconate incubation led to a shortening of cell length, followed by a 5.3% increase after 5 min. The CP/CA angle under potassium chloride was decreased (97.0 degrees) and was then increased under the influence of potassium gluconate (110.7 degrees) as a result of cuticular plate tilting. Cell shrinkage after fixation depended on the fixative's osmolarity and on the GA concentration. Increased GA levels amplified cell shrinkage from 34% for hypo-osmolar solutions to 15% in iso-osmolar and 29% in hyperosmolar solutions. The CP/CA angle of native and incubated OHCs was not different from those fixed with GA. The present data provide a rational basis for isolated OHC shape parameters. Moreover, functionally induced changes can be better interpreted when OHCs are influenced by fixatives, as shown in the GA experiments.

Animals↗
PubMedDate not supplied

Porcine tibia is a poor substitute for human cadaver tibia for evaluating interference screw fixation.

BACKGROUND: Animal tissues are commonly used in anterior cruciate ligament graft fixation studies. HYPOTHESIS: Porcine bones and tendons provide good surrogates for human cadaver tissues in the biomechanical evaluation of anterior cruciate ligament reconstruction. STUDY DESIGN: Randomized experimental study. METHOD: Three different tissue models-pure porcine (porcine graft fixed in porcine tibia, group 1), combination (human hamstring graft and porcine tibia, group 2), and pure human (human graft and tibia, group 3)-were compared using both cyclic-loading and subsequent single-cycle load-to-failure tests to assess the effect of graft and bone tissue source (porcine vs human) on the fixation strength of anterior cruciate ligament reconstruction. RESULTS: In the cyclic-loading test, the displacement (slippage) after 1500 cycles was 2.0 mm +/- 0.7 mm, 1.6 mm +/- 0.4 mm, and 4.4 mm +/- 1.9 mm for groups 1, 2, and 3, respectively (P <.001 between 1 and 2 vs 3). In the subsequent single-cycle load-to-failure test, the corresponding average yield loads were 668 N +/- 157 N, 962 N +/- 238 N, and 448 N +/- 98 N, all differences being statistically significant. CONCLUSIONS: In comparison to young human cadaver tibia, porcine tibia underestimate graft slippage and overestimate the failure load of the soft tissue graft in anterior cruciate ligament reconstruction. CLINICAL RELEVANCE: Porcine tibia does not provide a reasonable surrogate for human cadaver tibia for evaluating ACL reconstructions.

Adolescent↗
PubMed1984

The prognostic significance of histologic subtyping in small cell carcinoma of the lung.

Previously untreated patients with small cell carcinoma of the lung (SCCL), who were treated at the Medical College of Wisconsin with combined chemotherapy and radiation therapy, were retrospectively subtyped according to the 1981 World Health Organization Lung Cancer Classification. Of 54 evaluated patients, 27 (50%) had "oat cell" subtype, 22 (41%) "intermediate cell" variety, and five (9%) were classified as "combined" type. There was no significant difference in response to therapy or median survival between the subtypes. In addition to the absence of prognostic significance among the subtypes, there were many technical factors affecting accuracy of subtyping, including tissue-crushing artifacts, size of biopsy materials, fixation of tissue samples, and variation of subtypes within the same biopsy. We conclude that subtyping of SCCL should not be construed as a prognostic tool or guideline to therapy. However, the recognition that SCCL may manifest in a variety of histologic patterns, some of which may be misinterpreted as a histology other than SCCL, is probably more important for choice of therapy and prognosis than the individual subtypes.

Carcinoma, Small Cell↗
PubMed1978

Ultrastructural localization of nonheme celluar iron with ferrocyanide.

The Prussian blue reaction was evaluated at the ultrastructural level as a cytochemical method to identify ferric and ferrous iron in rat bone marrow and splenic macrophages. Satisfactory tissue preservation and staining were achieved after fixation for 1 hr in 3% glutaraldehyde and exposure for 30 min to Perls's ferrocyanide solution before routine osmication and embedding. The acid ferrocyanide solution formed cuboidal and irregular electron-opaque deposits which localized ferric iron in the macrophage siderosomes and hyaloplasm. When thin sections were directly stained with the acid ferrocyanide, the stain deposits were much less distinct. The size and number of cytes exhibited sparse evenly distributed stain deposits. Several cells displayed abundant precipitates on the inner surface of the plasmalemma. Prussian blue precipitates were occasionally seen in mitochondria and nuclear euchromatin. Although osmium tetroxide post-fixation improved tissue preservation, it did not enhance the density of the ferri-ferrocyanide precipitate. The ferrocyanide solution yielded cuboidal deposits also in clots impregnated with ferritin, and electron diffraction analysis confirmed the symmetrical crystal structure of these stain precipitates. Smaller irregular precipitates were formed in clots impregnated with FeCl3, or Fe2 (SO4)3 solutions, despite the equally interpreted as indicating that the iron hydroxide core or protein structure of ferritin and hemosiderin contributed to the formation of the ultrastructurally evident cuboidal precipitates, but were not necessary for the formation of a colored reaction product. The acid ferrocyanide solution failed to stain clots formed in FeCI2, CuCI2 or CuCI solutions. Staining with a ferricyanide solution identified only sparse foci of ferrous iron in some siderosomes. This study demonstrates that the Prussian blue reaction can be used ultrastructurally to localize iron cations bound to some nonheme iron binding proteins.

Animals↗
PubMed1986

A method of rapid fixation of large biopsy specimens using microwave irradiation.

This report describes the use of microwave irradiation for the rapid fixation of large biopsy specimens. Two hundred and twelve fresh large specimens subjected to non-ionizing irradiation in a domestic microwave oven (600 watt output, 2450 MHz) for 4-9 min were rendered sufficiently firm to be dissected and sampled immediately without the need for any formalin fixation. The tissues hardened in this manner remained pliable, retained much of their natural colour and were free of noxious fumes. Lymph nodes became opaque and firm and their pink-tan colour contrasted with the bright yellow of adipose tissue, making them easily dissectable. This procedure, combined with a further 4-7 min exposure to microwaves of the trimmed tissue blocks (in batches of 40), completed fixation and allowed the specimens to be processed on a 3 h 15 min cycle in an autoprocessor which did not contain formalin.

Biopsy↗
PubMed1998

Fibrin tissue adhesive in otolaryngology-head and neck surgery.

In otolaryngology-head and neck surgery, fibrin tissue adhesive (FTA) is primarily used for fixation of tissues, for attaining hemostasis, or for drug delivery. It can be used for positioning implants or ossicles in the middle ear or as a sealant in closure of cerebrospinal fluid leaks. FTA is an excellent hemostatic agent and can be used for controlling capillary bleeding along the cut surface of muscle or in a previously operated site. As a delivery system, FTA can be used to administer antibiotics, chemotherapeutic agents, or growth factors. New technology is providing safer homologous products, stronger autologous products with higher fibrinogen levels, and better applicators.

Animals↗
PubMed2001

Maintenance of soft tissue changes after rigid versus wire fixation for mandibular advancement, with and without genioplasty.

OBJECTIVE: This multisite prospective randomized clinical trial examined 2-year longitudinal soft tissue profile changes after bilateral sagittal split osteotomy for mandibular advancement by using rigid or wire fixation, with and without genioplasty. STUDY DESIGN: The study sample consisted of 127 subjects. The rigid-fixation group (n = 78) received 2-mm bicortical position screws, whereas the wire-fixation group (n = 49) received inferior border wires. In the rigid-fixation group, 35 subjects underwent genioplasty, whereas 24 subjects underwent genioplasty in the wire-fixation group. Soft tissue profile changes of labrale inferius, B-point, and pogonion were obtained from digitized cephalometric films taken immediately before surgery and up to 2 years after surgery. RESULTS: Regardless of fixation technique, subjects who had genioplasty in conjunction with the mandibular advancement had the largest surgical movement and the largest postsurgical change (P <.05). When all variables were constant, fixation technique was associated with maintenance of soft tissue change. Subjects who underwent rigid fixation maintained more soft tissue change than patients who underwent wire fixation. CONCLUSIONS: These findings suggest that subjects undergoing rigid fixation and genioplasty maintained the most soft tissue advancement.

Adult↗
PubMed1993

Rapid fixation and embedding method for immunocytochemical studies of tomato spotted wilt tospovirus (TSWV) in plant and insect tissues.

A new rapid fixation and embedding technique using microwave energy was evaluated for immunolabelling and examination of ultrastructure of plant and insect cells. Tissues in gluteraldehyde-paraformaldehyde were fixed for fifteen seconds in a microwave at 100% power, and dehydrated. Microwave energy was then used to polymerize the London Resin White (LR White) acrylic resin during the embedding process. Embedded specimens were then thin sectioned (90 nm) and treated with anti-tomato spotted wilt tospovirus (TSWV) antiserum followed by protein A-gold label, or antisera against a TSWV encoded nonstructural protein followed by goat anti-rabbit gold label. Using this technique, structural and nonstructural proteins of TSWV were readily detected and specifically labelled in cells of the insect vector, the western flower thrips, Frankliniella occidentalis (Pergande), and in infected cells of the plant species, Emilia sonchifolia L.

Animals↗
PubMed1991

Interrelationships of ultrastructure and function in the microvasculature of normal and ischaemic myocardium.

This paper reviews various methods involving electron microscopy that have been used to investigate the ultrastructure of the vasculature of the normal and diseased heart. Whereas scanning electron microscopy is more commonly employed to record surface topography, it can be used to examine freeze-fracture planes within the myocardium and, using heavy-metal staining and back-scattered electron imaging, to examine large 2-mu-thick resin-embedded sections through the heart. The latter technique allows the comparison of structural alterations across the wall of the heart and thus accurate definition of the transmural progression of pathological processes. Transmission electron microscopy can then be used to provide more detailed information from precisely localised regions. Human myocardium can be usefully studied up to 12 hours post-mortem provided that suitable control material is included. Intravascular tracers including low-viscosity resin and nuclear track emulsion can be used to determine whether or not particular vessels allow flow at the time of fixation, and thus changes in the pattern of flow through the microvasculature due to ischaemia and reperfusion can be quantified and defined. Particular care is required in the fixation of ischaemic tissues because oxygen dissolved in the fixative can lead to the rapid formation of oxygen-free radicals on contact with the tissue. This produces artefactual reoxygenation damage characterised by membrane disruption and cell and organelle swelling, which has previously been attributed to ischaemic injury per se. Bubbling glutaraldehyde with nitrogen substantially reduces this artefact.

Animals↗
PubMed1995

An improved immunolabeling method for microtubular cytoskeleton in poplar (Populus nigra L.) free nuclear endosperm.

We investigated immunocytochemical staining of microtubular cytoskeleton of free nuclear endosperm, a tissue which is particularly difficult to fix. This tissue requires fixation for 45 hr to preserve the integrity of the microtubular network after paraformaldehyde based fixation. Low glutaraldehyde concentration in the fixative and the ethanol dehydration retains beta-tubulin antigenicity and the former improves preservation of tissue structure. An ethanol-free embedding method is recommended for immunocytochemical studies of ethanol sensitive target proteins.

Cell Nucleus↗
PubMed2005

Comparison of volumetric bone mineral density in the tibial region of interest for ACL reconstruction.

Adequate tibial bone mineral density (BMD) is essential to soft tissue graft fixation during anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to compare volumetric bone plug density measurements at the tibial region of interest for ACL reconstruction using a standardized immersion technique and Archimedes' principle. Cancellous bone cores were harvested from the proximal, middle, and distal metaphyseal regions of the lateral tibia and from the standard tibial tunnel location used for ACL reconstruction of 18 cadaveric specimens. Proximal tibial cores displayed 32.6% greater BMD than middle tibial cores and 31.8% greater BMD than distal tibial cores, but did not differ from the BMD of the tibial tunnel cores. Correlational analysis confirmed that the cancellous BMD in the tibial tunnel related to the cancellous BMD of the proximal and distal lateral tibial metaphysis. In conjunction with its adjacent cortical bone, the cancellous BMD of the region used for standard tibial tunnel placement provides an effective foundation for ACL graft fixation. In tibia with poor BMD, bicortical fixation that incorporates cortical bone from the distal tibial tunnel region is recommended.

Aged↗
PubMed2005

Microwave-stimulated formaldehyde fixation of experimental renal biopsy tissues: computerised morphometric analysis of distortion artefacts.

Although microwave irradiation has been used in the histopathology laboratory for several years, there has been minimal published experimental data on its effects on the technical and staining quality of histological sections. Furthermore, it has not been clear whether the advantages gained in reduction of fixation and staining duration has been at the expense of increasing architectural distortion to the tissues. We report here our experience with computerised morphometric analysis to investigate glomerular artifacts caused by microwave-stimulated fixation of renal tissues. 39 rat and 33 human autopsy kidney samples were subjected to (1) fixation in neutral buffered formaldehyde (control), (2) microwave-stimulated fixation followed by neutral buffered formaldehyde, and (3) neutral buffered formaldehyde followed by microwave irradiation. In addition, the effect of post-fixation in 70% ethanol was also investigated. Microwave irradiation was delivered through a dedicated laboratory microwave oven at 80% power and at 55 degrees C for 3 minutes. The different fixation methods were compared with regards to shrinkage (distortion) to glomerular structures (glomeruli and Bowman's spaces) on H and E sections, as determined by morphometric image analysis using a temporary assembled-system consisting of a trinocular microscope, a digital video camera and personal computer. A FlashPoint VGA 3.3 film-grabber card was used to capture images for morphometric analysis by using a Scion Image program. Morphometric analysis of glomerular structures showed that microwaves caused more shrinkage to the area bounded by the Bowman's capsule than the glomerulus proper, but post-fixation with ethanol reduced this shrinkage. These findings have implications on the logistics of tissue preparation of renal biopsies in clinical practice.

Animals↗
PubMed1987

Evaluation of fixation methods in cruciate ligament replacement.

Laboratory studies designed to simulate in vivo loading of a ligament graft and fixation method are affected by the age of the cadaveric donor, the types of tissue and fixation device employed, and the testing methods used. The use of older donors compromises the graft bone, underlying bone bed, and soft tissue. Staples, sutures, and screws all provide different fixation strengths depending on the tissue to be held. Cyclic testing of the graft better evaluates the performance of the composite during the activities of daily living, while high-speed failure tests indicate the replacement's ability to resist a traumatic injury. Several studies were examined in light of these factors. Each study had certain merits but also limitations. Further studies are required for careful evaluation of the cyclic response of cancellous screws of different sizes, barbed staples, and other methods of graft fixation. Only then can recommendations be made as to the best device to use for achieving the clinical goals of joint stability, adequate resistance to traumatic loads, and proper graft attachment healing.

Biomechanical Phenomena↗
PubMed1992

Cholinesterase histochemistry in the human brain: effect of various fixation and storage conditions.

Human brains fixed in 3 conventional solutions were used to compare acetylcholinesterase and butyrylcholinesterase labeling after being processed by the same histochemical procedure. The best fixative was found to be 4% paraformaldehyde in a 0.1 M phosphate buffer for 24-42 h. The addition of 2% glutaraldehyde to 2% paraformaldehyde for the same fixation time reduced the staining intensity of both enzymes. Formalin after 2 days resulted in a lighter staining intensity of fibers, senile plaques and neurofibrillary tangles, whereas after 10 days it caused the near disappearance of acetylcholinesterase-positive fibers. Finally, after more than 10 days in formalin, a certain number of senile plaques and a few neurofibrillary tangles could be observed, and those only in the case in which the substrate concentration and incubation time were increased. The fixed tissue, in either blocks or sections, can be stored for more than 1 year in a glycol solution at -17 degrees C, without the inconvenience of freezing, with good histology and histochemical preservation of both enzymes.

Acetylcholinesterase↗
PubMed1994

The Mitek bone anchor: application to the hand, wrist and elbow.

Mitek (Norwood, MA) bone anchors were used to attach soft tissue to the bones of the hand, wrist, and elbow in 66 procedures (166 anchors). The technical difficulties, initial fixation, long-term stability, and postoperative complications were retrospectively reviewed. The technique was easy to learn and to use. Intraoperatively, secure fixation of soft tissue to bone was accomplished in every case, and follow-up x-ray films showed that 65 of the implants remained securely anchored in bone. The far cortex was penetrated six times, resulting in two complications. The Mitek bone anchor is an excellent technique for achieving soft-tissue fixation in the hand and upper extremity, but penetration of the far cortex should be avoided.

Adolescent↗
PubMed2002

Ki-67 antigen detection in unstained and destained cytologic samples.

OBJECTIVE: To evaluate the effect of different tissue preservation, fixation and staining procedures on the expression of proliferation-associated Ki-67 antigen in cytologic samples to establish an easy and uniform way to handle cytologic specimens with an automated staining technique. STUDY DESIGN: Multiple touch imprints were made from eight breast tumors. The specimens were treated according to different protocols, and Ki-67 nuclear expression was compared to that in the corresponding histologic sections. RESULTS: In the unstained specimens, air drying at room temperature for up to four months or ethanol spray fixation preserved the material and offered excellent results. Processing effectively removed previous stain without additional chemical destaining. Antigen retrieval was not achieved in the previously Giemsa stained imprints and was suboptimal in those stained according to Papanicolaou. CONCLUSION: Immunocytochemical detection of Ki-67 is recommended for previously unstained cytologic specimens.

Cytological Techniques↗