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At least 55 records · Page 3Linked to original sources

Apoptosis of retinal ganglion cells in anterior ischemic optic neuropathy.

We identified retinal ganglion cells undergoing apoptosis, a form of programmed cell death, in an eye of a 70-year-old man with anterior ischemic optic neuropathy. The TUNEL (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin end nick labeling) staining and the presence of condensed, fragmented nuclear bodies were used to identify apoptotic cells. Examination of TUNEL-stained retinal sections revealed occasional cells in the ganglion cell layer with pyknotic nuclei and brown reaction product, representing positive staining for chromosomal DNA breaks. Positive cells were sparsely distributed, consistent with the limited time in which apoptotic cells are identifiable before they are removed. The most likely explanation for these results is that injury to the retinal ganglion cell axon induces apoptosis. To our knowledge, this is the first report of human retinal ganglion cell apoptosis in an acute optic neuropathy.

Aged↗

Entry into the stationary phase is associated with a rapid loss of viability and an apoptotic-like phenotype in the opportunistic pathogen Aspergillus fumigatus.

When the opportunistic pathogen Aspergillus fumigatus entered the stationary phase, there was a rapid loss in cell viability which was associated with the appearance of markers characteristic of apoptosis, namely annexin V-FITC binding to the cytoplasmic membrane, demonstrating exposure of phosphatidylserine to the outer leaflet of the membrane; and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) staining of the nuclei, indicating DNA fragmentation. This was followed later by a loss of membrane integrity as revealed by propidium iodide staining. The development of the apoptotic phenotype was blocked when the protein synthesis inhibitor cycloheximide was added to the culture 1h prior to the onset of the stationary phase, demonstrating active participation of the cell. In addition, intracellular activity against substrates specific for caspase-1 and -8 also increased on stationary phase entry and the development of the apoptotic phenotype was blocked when the cell permeant caspase inhibitor Z-FAD-fmk was present in the medium. Cell death in A. fumigatus during the stationary phase therefore appears to share similarities to apoptotic cell death in higher eukaryotes and to be dependent on a caspase-like activity.

Amino Acid Chloromethyl Ketones↗

Immunohistochemistry of capillary hemangioblastoma. Immunoperoxidase-labeled antibody staining resolves the differential diagnosis with metastatic renal cell carcinoma, but does not explain the histogenesis of the capillary hemangioblastoma.

We used a battery of antigens to determine whether immunohistochemistry can (a) contribute to resolving the histogenesis of the stromal component of the capillary hemangioblastoma, and (b) answer cases of difficult pathologic differential diagnosis with metastatic clear cell carcinoma. The stromal cells of the capillary hemangioblastoma are antigenically polymorphous and may express immunoreactive erythropoietin, renin, keratin, Leu M1, Leu 7, actin, neuron-specific enolase, S100 protein, and glial fibrillary acidic protein. However, the use of epithelial membrane antigen allows certain histopathologic distinction between capillary hemangioblastoma and metastatic clear cell carcinoma.

Adenocarcinoma↗

Nuclear muscarinic acetylcholine receptors in corneal cells from rabbit.

PURPOSE: Previous studies have indicated that muscarinic acetylcholine receptors (mAChR) may be present in an unexpected, unique location and play a singular role in cellular growth regulation of rabbit corneal epithelium that may be of general physiologic significance if found in other cells. The purpose of this study was to examine rabbit corneas and corneal cells in culture to determine mAChR location and tissue distribution. METHODS: Using [3H]-propylbenzilylcholine mustard ([3H]PrBChM), which binds covalently to the active site of mAChR, rabbit corneal cross-sections, cultured corneal keratocytes, epithelial and endothelial cells, as well as nuclei isolated from these cultured corneal cells were labeled, stained, and autoradiographed. Nuclei labeled with [3H]PrBChM were further analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. RESULTS: Direct visual confirmation of the localization of mAChRs was obtained. MAChR were found in epithelial and endothelial layers of fresh-frozen corneal cross-sections, in cultured rabbit epithelial and endothelial cells, and on isolated rabbit epithelial and endothelial cell nuclei. mAChR were not detectable in keratocytes with these techniques. When [3H]PrBChM-labeled nuclei from cultured corneal cells were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, epithelial and endothelial samples showed specific mAChR binding, whereas binding to keratocyte nuclei was not detectable. CONCLUSIONS: As a result of these findings, a revised hypothesis is suggested for the locations and possible functions of mAChR in regulation of growth in corneal and other cells.

Acetylcholine↗

Induction of chondrocyte apoptosis following impact load.

OBJECTIVE: To investigate the presence and extent of chondrocyte apoptosis following impact load of articular cartilage in an in vivo model. DESIGN: An in vivo animal model, using a pendulum device and New Zealand White rabbits, was designed to study the effects of impact load on the development of chondrocyte apoptosis. Animals were placed into either a High Impact group or a Low Impact group, and the right medial femoral condyle was impacted with a single impact load. A sham operation was performed on the left limb, and this cartilage served as the control. SETTING: Academic medical center. PARTICIPANTS: New Zealand White rabbits (3 months). INTERVENTION: Impact load to the right medial femoral condyle. MAIN OUTCOME MEASURES: Three different methods were used to assess the presence and extent of chondrocyte apoptosis: 1) light microscopy (hematoxylin and eosin and terminal dUTP nick end labeling staining); 2) transmission electron microscopy; and 3) fluorescent microscopy with Hoechst 33342 staining. Secondary outcome measures included determination of the magnitude of impact force and time to peak force. RESULTS: Light microscopy demonstrated chondrocytes with changes consistent with apoptosis including condensed nuclei, deep eosinophilic cytoplasmic staining, and vacuolization within the impacted specimens. Terminal dUTP nick end labeling staining-stained specimens had a high degree of positively stained cells (60%) in both injured and uninjured specimens. Transmission electron microscopy of the impacted specimens demonstrated numerous chondrocytes with changes characteristic of apoptosis, including nuclear and cellular fragmentation, volume shrinkage, and cytoplasmic vacuolization. Eleven percent of the cells in the High Impact group had changes consistent with apoptosis, versus 3% for the low impact group and <1% for the sham specimens. The High Impact group received a statistically significant greater stress than the Low Impact group. Impact group (P < 0.05), and the average time to peak force was 0.021 seconds for each impact group. CONCLUSIONS: The current data strongly indicate that in vivo chondrocyte apoptosis can be stimulated by the application of a single, rapid impact load and that the extent of chondrocyte apoptosis is related to the amount of load applied. The contribution chondrocyte apoptosis makes to the development of posttraumatic arthritis following joint injury or intra-articular fracture still remains to be determined.

Animals↗

The use of silver-enhanced 1-nm gold probes for light and electron microscopic localization of intra- and extracellular antigens in skin.

We used colloidal gold (1-nm diameter) with silver enhancement, in conjunction with a low-temperature post-embedding immunolabeling technique, to localize several antigens in normal skin at both the light and the electron microscopic level within the same tissue blocks. Normal skin subjected to cyrofixation and cryosubstitution and embedded in Lowicryl K11M was used as a substrate. Semi-thin sections (1 micron) were incubated in primary antibody (against epidermal basement membrane zone associated antigens and two keratin sub-types), biotinylated secondary antibodies, and then in 1-nm gold-conjugated streptavidin. Finally, the 1-nm gold label was enhanced using silver staining. Labeling of both basement membrane and keratin antigens was well demonstrated, and the area in the semi-thin sections showing the best structural preservation and the greatest intensity of immunolabeling was used to identify the part of the block to be used for ultra-thin sectioning. Ultra-thin sections were treated using a similar procedure to that employed for semi-thin sections. The labeling with silver-enhanced 1-nm gold probes was intense and readily visible by electron microscopy, even at low magnification. We have found this technique to have a high degree of specificity and sensitivity for labeling both intra- and extracellular antigens in skin, with the added advantage of providing the means for studies at both light microscopic and electron microscopic level.

Antibodies↗

Activation of voltage-sensitive sodium channels during oxygen deprivation leads to apoptotic neuronal death.

Sodium (Na(+)) entry into neurons during hypoxia is known to be associated with cell death. However, it is not clear whether Na(+) entry causes cell death and by what mechanisms this increased Na(+) entry induces death. In this study we used cultures of rat neocortical neurons to show that an increase in intracellular sodium (Na(i)(+)) through voltage-sensitive sodium channels (VSSCs), during hypoxia contributes to apoptosis. Hypoxia increased Na(i)(+) and induced neuronal apoptosis, as assessed by electron microscopy, annexin V staining, and terminal UDP nick end labeling staining. Reducing Na(+) entry with the VSSC blocker, tetrodotoxin (TTX), attenuated apoptotic neuronal death via a reduction in caspase-3 activation. Since the attenuation of apoptosis by TTX during hypoxia suggested that the activation of VSSCs and Na(+) entry are crucial events in hypoxia-induced cell death, we also determined whether the activation of VSSCs per se could lead to apoptosis under resting conditions. Increasing Na(+) entry with the VSSC activator veratridine also induced neuronal apoptosis and caspase-3 activation. These data indicate that a) Na(+) entry via VSSCs during hypoxia leads to apoptotic cell death which is mediated, in part, by caspase-3 and b) activation of VSSCs during oxygen deprivation is a major event by which hypoxia induces cell death.

Animals↗

Cell cycle analysis of asynchronous cell populations by flow cytometry using bromodeoxyuridine label and Hoechst-propidium iodide stain.

Continuous labelling of cells with deoxybromouridine (BrdUrd) followed by staining with a bis-benzimidazole (Hoechst 33258) and a phenanthridinium (propidium iodide or ethidium bromide) allows the cells to be separated by flow cytometry according to the extent of their DNA replication. This BrdUrd-Hoechst/PI method has been used mainly to observe perturbations of the cell cycle in synchronously growing cells. In this paper we demonstrate that, when the method is applied to asynchronously dividing cells, more extensive information can be derived about the effects of cytotoxic and other treatments on the kinetics of the cell cycle. The interpretation of the data is explained, the effects of different types of cytotoxic agent are described, and the method is compared briefly to other methods for following cell cycle kinetics.

Animals↗

A practical quick staining method using hydrochloric acid-fast metachromatic dye for megakaryocytes.

A specific stain using violet polymethine dye (VPM stain) for megakaryocytes was first developed by Kass (1995). We have modified this method for practical use in bone marrow specimens. The modified VPM stain labels megakaryocytes very well, while other marrow cells are poorly colorized. This staining procedure was more stable, and its color intensity was finer and clearer than the original. Using this stain, morphologic classification of megakaryocytes in bone marrow specimens from 11 normal and 8 myelodysplastic syndrome (MDS) patients was performed. Many megakaryocytes observed in MDS patients were juvenile compared with normal subjects according to their morphology. Blasts from acute megakaryoblastic leukemia (M7) and from a megakaryoblastic cell line (Mo7e) were also clearly stained with our method. This staining method is practical and very useful for rapid identification of megakaryocyte distribution and morphology.

Bone Marrow Examination↗

Caspase activation as an apoptotic evidence in the gerbil hippocampal CA1 pyramidal cells following transient forebrain ischemia.

To determine whether apoptotic process is involved in the delayed neuronal death in hippocampal CA1 region following forebrain ischemia in gerbils, time dependent activation of caspase and DNA fragmentation were evaluated by immuno-staining and terminal dUTP nick-end-labeling staining, respectively. After transient forebrain ischemia in gerbils, activation of apoptosis related caspase, including caspase-3, was apparent, and it preceded DNA fragmentation in CA1 region. These observations suggest that apoptotic process is involved in hippocampal delayed neuronal death.

Animals↗

Immunocytochemical detection of sulphonylated DNA in tissue sections. An alternative to Feulgen staining of DNA.

We report here on a new sensitive and highly specific DNA staining technique which we have called sulpho-DNA staining. DNA staining is based on a sulphonylation reaction of 2'-deoxycytidine or cytidine that takes place in the 6th position of cytosine with ensuing immunodetection of the sulphonylated DNA. The specificity of DNA staining is introduced by the use of an antibody recognizing only modified DNA but not modified RNA, by recourse to an additional acid hydrolysis step which destroys RNA but not DNA. We describe here the optimal conditions for the sulphonylation of DNA using O-methylhydroxylamine and metabisulphite as reactants. The new DNA stain labels all nuclei in either normal human tissue or in tumor cells. For nuclear DNA the staining signal is higher for the sulpho-DNA staining than for the Feulgen staining for nuclear DNA. This new DNA staining technique is suitable for use on tissue sections as well as on cytosmears.

Animals↗

Antiinflammatory effects of amniotic membrane transplantation in ocular surface disorders.

PURPOSE: To determine whether the sequestration of inflammatory cells plays a role in the antiinflammatory effects of amniotic membrane transplantation to the ocular surface. METHODS: Amniotic membrane grafts were prepared from placental tissue procured from mothers undergoing planned Cesarean sections. A detailed explanation was given to all donors, and a written consent was obtained before processing. Amniotic membrane tissue was dissected into 3- x 3-cm segments, rinsed in phosphate buffered saline, and stored in dimethyl sulfoxide solutions at -80 degrees C until use. In a clinical series, amniotic membrane patches of the ocular surface were performed in 20 eyes of 20 patients with persistent corneal epithelial defects, or as a prophylactic measure after corneal limbal transplantation. Amniotic membrane patches were harvested after a 1-week observation period and were subjected to histopathologic examinations by hematoxylin and eosin staining. Inflammatory cells trapped within the amniotic membrane were labeled by immunocytochemistry using anti-CD14, CD4, CD8, and CD20 antibodies. TUNEL (TdT-mediated dUTP nick end labeling) staining was done to observe cells undergoing apoptosis. The T cell line Molt 4 was co-cultured with amniotic membrane in vitro to observe adhesion of T cells to amniotic membrane. RESULTS: Various degrees of inflammatory cell infiltration were observed in all clinical samples of amniotic membrane patches. Most of the inflammatory cells stained positively with anti-CD14 antibodies, indicating that these cells were of monocyte/macrophage lineage. Subsets of T cells included both CD4(+) and CD8(+) cells, whereas CD20(+) cells were sparse. TUNEL assays revealed that trapped inflammatory cells exhibited characteristics of cells undergoing apoptosis. Molt 4 invaded within amniotic membrane in an in vitro assay, which was not inhibited by blocking antibodies to beta1 and beta2 integrins. CONCLUSION: Amniotic membrane attracts and traps inflammatory cells infiltrating the ocular surface, which may explain some of the antiinflammatory properties of the fetal tissue.

Amnion↗

Varicella-zoster virus ORF63 inhibits apoptosis of primary human neurons.

Virus-encoded modulation of apoptosis may serve as a mechanism to enhance cell survival and virus persistence. The impact of productive varicella-zoster virus (VZV) infection on apoptosis appears to be cell type specific, as infected human sensory neurons are resistant to apoptosis, yet human fibroblasts readily become apoptotic. We sought to identify the viral gene product(s) responsible for this antiapoptotic phenotype in primary human sensory neurons. Treatment with phosphonoacetic acid to inhibit viral DNA replication and late-phase gene expression did not alter the antiapoptotic phenotype, implicating immediate-early (IE) or early genes or a virion component. Compared to the parental VZV strain (rOKA), a recombinant virus unable to express one copy of the diploid IE gene ORF63 (rOka deltaORF63) demonstrated a significant induction of apoptosis in infected neurons, as determined by three methods: annexin V staining, deoxynucleotidyltransferase-mediated dUTP-biotin nick end label staining, and transmission electron microscopy. Furthermore, neurons transfected with a plasmid expressing ORF63 resisted apoptosis induced by nerve growth factor withdrawal. These results show that ORF63 can suppress apoptosis of neurons and provide the first identification of a VZV gene encoding an antiapoptotic function. As ORF63 is expressed in neurons during both productive and latent infection, it may play a significant role in viral pathogenesis by promoting neuron survival during primary and reactivated infections.

Apoptosis↗

[Protective effect of exogenous bcl-2 on spinal cord motoneurons following sciatic nerve axotomy in the rat].

The aim of this study was to investigate the protective effect of exogenous bcl-2 on spinal cord motoneurons following sciatic nerve axotomy. After epineurium suturing, sense bcl-2 (Ad/s-bcl-2), antisense bcl-2 (Ad/as-bcl-2), or reporter gene lacZ (Ad/lacZ) recombinant adenovirus or NS was injected into the sciatic nerve 0.5 cm distant from the sutured point respectively in different groups. The rats were transcardially perfused with 4% paraformaldehyde on postoperative 48 h, 7 d, 15 d and 30 d respectively and the spinal cords of L4 to L6 were harvested. X-gal staining, bcl-2 in situ hybridization and immunohistochemical staining, TUNEL (terminal deoxynucleotidyl transferase mediated dUTP nick end labeling) staining and AChE (acetyl cholinesterase) histochemical staining were used. We observed that the exogenous lacZ gene was expressed in the spinal cord of Ad/lacZ group, and sense bcl-2 significantly decreased the number of apoptotic motoneurons and the decreasing degree of AChE activity of the motoneurons in the spinal cord induced by sciatic nerve axotomy and accelerate AChE activity recovery. However, antisense bcl-2 increased the number of apoptotic motoneurons and the decreasing degree of AChE activity of the motoneurons in the spinal cord induced by sciatic nerve axotomy and prolonged AChE activity recovery. These results demonstrate that exogenous bcl-2 may protect motor neurons from injury induced by peripheral nerve axotomy.

Adenoviridae↗

Identical reactivity of monoclonal antibodies HNK-1 and NC-1: conservation in vertebrates on cells derived from the neural primordium and on some leukocytes.

NC-1 and HNK-1, two mouse monoclonal antibodies raised against quail ciliary ganglion and a human leukemic cell-line, respectively, were found to display the same pattern of reactivity. Species investigated included human, rodents, birds and amphibians. In 1- to 3-day-old avian embryos, migrating crest cells are stained, whereas in older animals neuroepithelial cells and neurons are labelled. Staining with fluorescein isothiocyanate-conjugated NC-1 is blocked by preincubation with HNK-1. In immunoblot analyses both antibodies recognize the same pattern of bands which are different in central and peripheral nervous systems and vary during development. Thus, HNK-1/NC-1 provides a useful tool for investigating the ontogeny of neural and lymphocytic cells carrying this determinant, which, in view of its high degree of conservation during vertebrate evolution, may play an important part within the haematopoietic and nervous systems.

Animals↗