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At least 595 records · Page 33Linked to original sources
PubMed1981

Ultrastructure of chicken cardiac muscle as studied by double immunolabeling in electron microscopy.

The ultrastructural localization of alpha-actinin and vinculin in chicken cardiac muscle was studied by double indirect immunoelectron microscopy, using ferritin and iron-dextran (Imposil) as the electron-dense markers conjugated to the secondary antibodies, on ultrathin frozen sections of fixed tissue. Fixation and immunolabeling procedures were developed that permitted maximal retention of the two proteins at their natural sites as well as their adequate labeling. alpha-Actinin was found both on the Z-bands, as expected, and near the fascia adherens of the intercalated discs, whereas vinculin was confined to the latter sites. At the fascia adherens, the double labeling results clearly showed that vinculin was situated closer to the membrane than was alpha-actinin. These results, coupled with earlier observations, suggest that vinculin may participate in the linkage of actin-containing microfilament bundles to membranes in a variety of cell types.

Actinin↗
PubMed2001

Rapid polymerisation with microwave irradiation for transmission electron microscopy.

Successful results of microwave polymerisation of different epoxy formulations have been reported in the literature. The present study was intended to shorten the time needed for polymerisation of epoxy resin by the use of a microwave technique. A standard double fixation and tissue processing was applied to samples of rat kidney tissue. Tissue samples from the control group were polymerised in a conventional oven at 60 degrees C for 48 h, while tissue from the experimental group was irradiated in a microwave oven, initially at 900 W for 10 min and then at 360 W for another 100 min. During this irradiation, the sealed BEEM capsules were submerged in a water bath, so that the temperature rise was uniform and constant. This resulted in a homogeneous and rapid polymerisation. The cutting properties of the blocks in both groups were similar and no noticeable difference in the quality of the sections was evident when evaluated with TEM. The results showed that the use of a microwave oven reduced the time needed for the polymerisation of Epon blocks without any loss in quality.

Animals↗
PubMed2001

Facial reanimation surgery utilizing the Mitek anchor system: A case report.

A flaccid hemi-face is frequently the most noticeable and cosmetically unacceptable consequence of facial nerve palsy, whether due to trauma, Bell's palsy or other etiologies. A variety of face-lift and reanimation techniques have been utilized in the past, but with time, these frequently require further surgery. We describe the use of Mitek (Norwood, MA) suture anchors for cheek resuspension in a patient with facial palsy. This system is composed of a drill guide, drill, inserter, and anchor. Although the titanium alloy anchors come in multiple sizes, the Mini GII Anchor is typically most appropriate for use in facial procedures. The actual size of the Mini GII Anchor is 1.8 mm in diameter and 5.4 mm in length. Two small arched prongs extend from the body of the anchor, and an eyelet at the superior surface is used for suture placement. When placed into a pre-drilled hole with the insertion tool, the prongs extend, effectively fixing the anchor in place. The drill guide protects adjacent soft tissues during the drilling process and allows drilling to a predetermined fixed depth. Sutures attached to the anchor may then be used for soft tissue fixation to bone.

Journal Article↗
PubMed2006

A 'best practices' approach to neuropathologic assessment in developmental neurotoxicity testing--for today.

A key trait of developmental neurotoxicants is their ability to cause structural lesions in the immature nervous system. Thus, neuropathologic assessment is an essential element of developmental neurotoxicity (DNT) studies that are designed to evaluate chemically-induced risk to neural substrates in young humans. The guidelines for conventional DNT assays have been established by regulatory agencies to provide a flexible scaffold for conducting such studies; recent experience has launched new efforts to update these recommendations. The present document was produced by an ad hoc subcommittee of the Society of Toxicologic Pathology (STP) tasked with examining conventional methods used in DNT neuropathology in order to define the 'best practices' for dealing with the diverse requirements of both national (EPA) and international (OECD) regulatory bodies. Recommendations (including citations for relevant neurobiological and technical references) address all aspects of the DNT neuropathology examination: study design; tissue fixation, collection, processing, and staining; qualitative and quantitative evaluation; statistical analysis; proper control materials; study documentation; and personnel training. If followed, these proposals will allow pathologists to meet the need for a sound risk assessment (balanced to address both regulatory issues and scientific considerations) in this field today while providing direction for the research needed to further refine DNT neuropathology 'best practices' in the future.

Animals↗
PubMed1964

PROTEIN SYNTHESIS, STORAGE, AND DISCHARGE IN THE PANCREATIC EXOCRINE CELL. AN AUTORADIOGRAPHIC STUDY.

The synthesis, intracellular transport, storage, and discharge of secretory proteins in and from the pancreatic exocrine cell of the guinea pig were studied by light- and electron microscopical autoradiography using DL-leucine-4,5-H(3) as label. Control experiments were carried out to determine: (a) the length of the label pulse in the blood and tissue after intravenous injections of leucine-H(3); (b) the amount and nature of label lost during tissue fixation, dehydration, and embedding. The results indicate that leucine-H(3) can be used as a label for newly synthesized secretory proteins and as a tracer for their intracellular movements. The autoradiographic observations show that, at approximately 5 minutes after injection, the label is localized mostly in cell regions occupied by rough surfaced elements of the endoplasmic reticulum; at approximately 20 minutes, it appears in elements of the Golgi complex; and after 1 hour, in zymogen granules. The evidence conclusively shows that the zymogen granules are formed in the Golgi region by a progressive concentration of secretory products within large condensing vacuoles. The findings are compatible with an early transfer of label from the rough surfaced endoplasmic reticulum to the Golgi complex, and suggest the existence of two distinct steps in the transit of secretory proteins through the latter. The first is connected with small, smooth surfaced vesicles situated at the periphery of the complex, and the second with centrally located condensing vacuoles.

Animals↗
PubMed1982

Immunocytochemical localization of the receptor for asialoglycoprotein in rat liver cells.

We used high-resolution immunocytochemistry on ultrathin frozen sections labeled with colloidal gold to study the subcellular distribution of the asialoglycoprotein receptor in rat liver. The receptor was localized along the entire hepatocyte plasma membrane, including the bile capillary membrane, but was scarce intracellularly. Sinusoidal lining (Kupffer) cells and blood cells showed no immunoreactivity. In liver cells of rats injected with 1 to 100 micrograms of asialoorosomucoid (ASOR) 2-15 min before tissue fixation, endocytotic internalization of receptors at the blood front was conspicuous. At all times in this interval, receptor was present in approximately 100-nm vesicles and larger vacuoles adjacent to the sinusoidal plasma membrane. No other significant intracellular receptor was noted during the 15-min exposure to ASOR; in particular, lysosomes and Golgi complex were not labeled. Our observations, in combination with data from the literature which demonstrate that, under these conditions, the ligand is transferred further to the Golgi complex-lysosome region, suggest that the receptor and ligand are dissociated in the vicinity of the plasma membrane, after which the receptor rapidly returns to the cell surface.

Animals↗
PubMedDate not supplied

PlasmaKinetic bipolar vessel sealing: burst pressures and thermal spread in an animal model.

BACKGROUND AND PURPOSE: Laparoscopic bipolar instruments are commonly employed to cauterize and divide tissue. A next-generation bipolar device has been developed that employs vapor pulse coagulation energy. We assessed the vessel-sealing capability of this device and quantified thermal spread during application. MATERIALS AND METHODS: Bilateral laparoscopic nephrectomy was performed on six common swine >25 kg. Five-millimeter clips and surgical staplers (US Surgical, Norwalk, CT) were utilized to perform nephrectomy on one side, while the Gyrus PlasmaKinetic bipolar device (Minneapolis, MN) was employed for the contralateral nephrectomy. Vessel-sealing capabilities were assessed via burst-pressure studies. The extent of thermal spread was measured after tissue fixation and hematoxylin and eosin staining. RESULTS: Surgical clips/vascular staplers adequately controlled/sealed renal hilar vessels with burst pressures nearing 300 mm Hg. The Gyrus bipolar device reliably sealed and divided renal arteries <or=5 mm with burst pressures averaging 291 mm Hg. Renal arteries above this size were not consistently sealed, but, with the exception of one technical error, renal veins of all sizes (3-12 mm) were reliably controlled (average burst pressure 288 mm Hg). Histologic evidence of thermal spread extended an average of 3.6 mm from the cut edges of arteries and 3.4 mm from the edges of veins. CONCLUSIONS: The Gyrus PlasmaKinetic bipolar device is capable of reliably sealing/ dividing arteries as large as 6 mm, although we recommend restricting its use to vessels no larger than 5 mm in diameter to allow a safety margin. In addition, porcine renal veins of all sizes are adequately controlled. These sealed vessels are able to withstand pressures approaching 300 mm Hg. Thermal spread affects only the area surrounding the divided vessel. Further clinical studies are warranted.

Animals↗
PubMed1999

Use of cultured cells as a control for quantitative immunocytochemical analysis of estrogen receptor in breast cancer. The Quicgel method.

Variation in tissue fixation, processing, and staining is largely responsible for poor reproducibility of estrogen receptor (ER) immunohistochemistry assays. A frozen, agar-suspended pellet of MCF-7 cells with known ER content was added to each of 55 samples of invasive breast carcinoma (IBC), serving as a control. Image analysis determined percentages of positive area (positive nuclei per total nuclei analyzed) and positive stain (sum of optical density of the positive nuclear area divided by sum of the optical density of all nuclei studied) of MCF-7 cells and IBC. MCF-7 cells had a mean value of 150 fmol/mg of ER by dextran-coated charcoal analysis. Image analysis of MCF-7 cells included with the 55 cases showed a mean positive area of 70.81. Positive staining from the IBC cases ranged from 0 to 98.5. By using the known ER content and the positive area of the MCF-7 cells, a conversion factor was used to translate the positive area of the clinical specimens to a femtomole equivalent, which for the 55 IBCs ranged from 0 to 1,790 (mean, 187). Inclusion of a control with known femtomole quantity of ER provides an internal standard for quality control and ER quantitation.

Adult↗
PubMed1981

An automated system for the handling, diluting, and dispensing of formaldehyde.

Automation can be applied to the repetitive and mechanical handling, mixing, and dispensing of formaldehyde, the most common tissue fixative in routine clinical laboratory use. A closed automated system is described that aspirates 37% formaldehyde from large, commercial sized 490 pound drums at a remote location, and delivers 10% formalin in ready-to-use form at a special faucet in the histology laboratory without human intervention. In addition to economy from a decrease in personnel handling time and from purchasing formaldehyde in bulk, it decreases the exposure of laboratory personnel to formaldehyde fumes.

Fixatives↗
PubMed1978

An automatic device for freeze-clamping of cardiac tissue within a fraction of the contraction cycle.

An automatic quick-freeze clamping device has been developed. Opposed pneumatic pistons filled with aluminium caps previously cooled in liquid nitrogen are used to compress a portion (100 to 200 mg) of the myocardium to a 0.15 to 0.20 mm thick wafer, colling the tissue from 37 degrees C to -15 degrees C within 10 ms. The clamp is triggered electronically from the R-wave of the ECG. This tissue fixation by freezing within 10 ms is sufficiently rapid to study oscillations of myocardial metabolite levels during the contraction cycle of isolated perfused hearts of small mammals such as the rat and guinea pig whose rate is 4 to 5 beats per second.

Animals↗
PubMed1999

Histamine monoclonal antibody for brain immunocytochemistry.

Among five monoclonal antibodies (AHA-1 to 5 mAbs) prepared against glutaraldehyde (GA)-conjugated histamine (HA) in our previous study, only mAb AHA-2 was found to detect HA specifically in rat brain neurons by an immunocytochemistry method (ICC) using GA as a tissue fixative. All the other mAbs, except for AHA-5, reacted with HA in the enterochromaffin-like cells (ECL cells) of rat stomach [Fujiwara et al. (1997) Histochem. Cell Biol. 107, 39-45]. Enzyme-linked immunosorbent assay (ELISA) binding and inhibition tests demonstrated that AHA-2 is specific for HA, with almost no detectable cross-reaction with any other established or putative amino acid neurotransmitters, LH-RH, TRH, or peptides with N-terminal histidines. ELISA assays also suggested that the AHA-2 mAb recognizes a HA epitope structure different from the one recognized by the AHA-1 mAb. The immunostaining patterns with AHA-2 mAb, as seen in the five subgroups of the tuberomammillary nuclei in the rat posterior hypothalamus, were very similar to those described by Inagaki et al. [(1988) Brain Res. 439, 402-405; (1990) Exp. Brain Res. 80, 374-380] and Panula et al. [(1984) Proc. Natl. Acad. Sci. USA 81, 2572-2576; (1988) J. Histochem. Cytochem. 36, 259-269] using polyclonal anti-HA serum. However, it was also noted that moderate numbers of immunoreactive nerve fibers projected into the median eminence. The present HA ICC method using AHA-2 mAb allows highly sensitive HA detection in brain, and thus might permit detailed studies of HA localization hitherto impossible using previously available anti-HA polyclonal antibodies produced against carbodiimide-conjugated HA.

Animals↗
PubMed1989

Normal histology of the colon.

We describe the normal gross anatomy and histology of the colon, with emphasis on the appearance of the mucosa as seen in the endoscopic biopsies. Various artifacts that may be encountered as a result of trauma from the biopsy forceps, incorrect orientation of the tissue, fixation, and the effects of laxatives and enemas are described and illustrated. Recommendations for optimum handling of biopsies are made.

Biopsy↗
PubMedDate not supplied

A mechanism for the decrease in stiffness of bioprosthetic heart valve tissues after cross-linking.

It has been reported that the elastic modulus of glutaraldehyde treated bioprosthetic valve materials is lower than that of fresh tissues. This finding appears paradoxic, because cross-linked tissues are usually stiffer than fresh ones. To investigate this phenomenon, the stiffness of 12 each of fresh and glutaraldehyde treated strips of porcine aortic valve cusps was measured at different levels of applied preload. To eliminate shrinkage effects, tissues were fixed while constrained at the gauge length. From paired comparisons of fresh versus fixed, it was found that glutaraldehyde fixed materials had a consistently lower stiffness than fresh tissue at low loads (0.39 N/m for treated vs 0.54 N/m for fresh at a 150 N/m preload), but no difference was found at high loads (1.09 N/m for treated vs 1.07 N/m for fresh at 600 N/ m preload). It is concluded that the observed drop in elastic modulus at low loads is a phenomenon associated with cross-linking of the collagen fiber matrix. Because a cross-linked matrix offers greater resistance to stretch, fixed tissue generates higher tensions at lower strains, at a point on the loading curve where the collagen fibers are more crimped and the slope of the curve is lower. At high loads, however, the stiffness of fixed tissues is equivalent to that of fresh. Measuring stiffness at a given stress or tension, rather than at a particular state of collagen fiber crimp, leads to the apparent lower stiffness of fixed tissues.

Animals↗
PubMed1991

Monoclonal antibody 1BE12 immunoreactivity with human endometrium. Correlations with hormone receptors and proliferation cell markers.

The monoclonal antibody (MAb) 1BE12 has recently been reported to react with several human normal and abnormal tissues. In human endometrium, it reacts more strongly with carcinomas than with normal tissue. To investigate the effectiveness of MAb 1BE12 in identifying cell proliferation in human endometrial cancers, 1BE12 immunocytochemical assays (ICAs) were performed on frozen (n = 47) and paraffin (n = 100) sections with subsequent computer-assisted microcytophotometric (SAMBA) evaluation of immunoprecipitate distribution. MAb 1BE12 immunoreactivity was not impaired by tissue fixation and paraffin embedding. It reacted with normal proliferative endometrium but not with normal secretory endometrium, and immunoreactivity increased with the degree of cell proliferation and malignancy, the amount of immunostaining being greater in invasive carcinomas than in normal proliferative endometrium and endometrial hyperplasia. ICAs showed no correlation between MAb 1BE12 immunoreactivity and estrogen and progesterone receptor antigenic sites. On the other hand, MAb 1BE12 staining in frozen sections increased with Ki67, EGFR, pHER-2/neu, and cathepsin immunostaining. These findings suggest that ICAs on frozen and paraffin-embedded biopsy specimens using MAb 1BE12 along with other markers can be useful for early detection and grading of endometrial carcinoma. The relevance of MAb 1BE12 to the selection of patients for laser ablation of the endometrium rather than hysterectomy is also discussed.

Antibodies, Monoclonal↗
PubMed1980

Some possible applications of computerized tomography in pathology.

Computerized tomography may be adaptable to microscopic and gross pathology. Low voltage (3 to 8 keV) X-ray histologic tomography of frozen 1 to 3 mm cylinders of tissue should provide atomic-number-dependent absorption coefficients because of photoelectric capture by the common light elements in such tissue. Fixation, sectioning, and staining artifacts would be obviated. Elements of a design for a rotate-only microgantry are described. For gross pathology, existing whole body scanners could be modified by finer collimation, longer exposure times, and higher X-ray fluxes to produce tomograms of much higher resolution than is possible during life, since movement and administered radiation dose would not be problematical. Suspected pathology could be needle aspirated, thus avoiding gross dissection where it is forbidden for religious or other reasons.

Autopsy↗
PubMed1997

Bidirectional armed needle: a useful surgical tool in plastic surgery.

We propose the application of a bidirectional armed needle, which facilitates suturing and soft-tissue fixation. This device can be used during the "back-and-forth" suturing method that is often used in centrofacial lift, nasolabial-fold correction, malar eminence suspension, submental platysmoplasty, canthopexy, etc. It is very useful for performing running mattress sutures and also for mini-invasive and other sophisticated procedures. The advantages of this needle includes a shorter operating time and lower morbidity. It is a useful tool with multiple applications in plastic surgery.

Needles↗
PubMed2003

The role of scleral buckle in experimental posterior penetrating eye injury.

PURPOSE: Although episcleral buckles are frequently placed as an additional procedure to vitreoretinal surgery, little is known about their independent effect after ocular trauma. The authors created a posterior penetrating ocular injury model to evaluate the isolated role of primary episcleral buckle placement. METHODS: Twenty eyes underwent surgery. The penetrating injury consisted of two 5-mm circumferential incisions placed five clock hours apart and 8 mm behind the limbus. A segmental episcleral buckle was placed over a randomly chosen injury site after wound closure. The degrees of fibrous proliferation, traction, and the presence of retinal detachment were evaluated on follow-up examinations. After enucleation and initial fixation, tissue sectioning was performed, and the greatest dimension of the fibrous proliferation at both wound sites was measured with a caliper. RESULTS: Two eyes were excluded from the study. Three eyes developed a retinal detachment; the remaining 15 eyes showed varying degrees of proliferation and traction on the retina. The greatest dimension of the fibrous proliferation at the buckle site (1.22 +/- 1 mm) was significantly different from that at the nonbuckle site (2 +/- 1.45 mm, P = 0.01). CONCLUSIONS: Primary episcleral buckle placement at the time of surgical repair reduces vitreous traction from the buckle site and decreases the degree of fibrovascular proliferation.

Animals↗
PubMed1984

Pulmonary pseudolymphoma.

Pseudolymphomas of the lung are extremely rare with approximately 30 cases reported in the literature. Histologically it may be impossible to distinguish a benign pseudolymphoma from a malignant lymphoma. Immunoperoxidase staining has been proposed to help predict the benign or malignant potential of these conditions. Results thus far have been inconclusive, but a monoclonal pattern has tended to predict malignant potential. We have reported a pulmonary pseudolymphoma that failed to stain with the immunoperoxidase technique due to improper tissue fixation. After four years of clinical follow-up, the patient remains disease free.

Aged↗