Search PubMed⌕ Search

Biomedical subjects

G Perry

Publications and source records attributed to G Perry.

At least 271 records · Page 15Linked to original sources
PubMed1986

Coexistence of cytokeratin, vimentin and neurofilament protein in human choroid plexus. An immunohistochemical study of intermediate filaments in neuroepithelial tissues.

The expression of intermediate filament proteins in human brain ependyma and choroid plexus epithelium has been studied by immunohistochemistry using a panel of monoclonal antibodies directed against all five classes of intermediate filaments. Ependymal cells express GFAP and vimentin filaments, whereas plexus epithelium simultaneously contains neurofilaments, cytokeratins and vimentin, a phenomenon not previously observed in normal cells in vivo. By means of specific antibodies we were able to establish that cytokeratins 8 and 18 but not 19 are present in plexus epithelium.

Aged↗
PubMed1986

Microtubules are not altered in the dystrophic chicken.

The association of an altered cytoplasmic microtubule complex in cells of the dystrophic chicken was investigated. Dystrophic chickens of lines 304 and 413 were compared with their genetically matched control, 412 (obtained from UC, Davis). Explants and trypsin-dissociated tissues were prepared from breast and heart muscles of chickens at 1, 3, 7, 14, 20, 40, 80 and 120 days ex ovo. The cells were cultured for 7 days and then processed for antitubulin immunofluorescence. Over 90% of the cells displayed an extensive cytoplasmic microtubule complex, although there was significant elevation of creatine phosphokinase in the dystrophic chickens after 20 days ex ovo. In both dystrophic and control preparations, one to two distinct functionally intact microtubule-organizing centers per cell were observed. Dystrophic and control chicken brain extracts demonstrated essentially the same extent of microtubule assembly as assayed by turbidity increase and protein in sedimentable polymer. SDS-PAGE revealed no significant differences in the microtubule proteins polymerized from the dystrophic and control brains. These results suggest that no significant alteration occurs in the structure, assembly or distribution of cytoplasmic microtubules in the cells of the dystrophic chicken.

Animals↗
PubMed1986

Electron microscopic localization of Alzheimer neurofibrillary tangle components recognized by an antiserum to paired helical filaments.

Paired helical filaments (PHF) are the main component of the Alzheimer neurofibrillary tangle; however, other elements, such as 10 and 15 nm straight filaments and granular amorphous components, are observed. In the present study, the localization of the antigenic determinants recognized by an antiserum to PHF fractions that does not recognize normal nervous tissue components is examined by electron microscopic immunocytochemistry. Employing the peroxidase-antiperoxidase procedure on neurofibrillary tangles in intact tissue, we found that the antiserum reacts with PHF and with granular amorphous material within the tangle. Following isolation of PHF by treatment with ionic detergent and labeling with immunogold, the antigenic determinants often occur at intervals rather than being uniformly distributed along the PHF. The distribution of the antigenic determinants recognized by this antiserum is similar to that previously observed for PHF determinants recognized by antibodies to neurofilament and microtubule-associated proteins. We conclude that PHF are heterogenous structures which contain PHF-specific as well as cytoskeleton-derived antigenic determinants.

Aged↗
PubMed1985

Characterization of a Ca2+-stimulated lipid peroxidizing system in the sea urchin egg.

Addition of calcium chloride to an egg homogenate of Strongylocentrotus purpuratus stimulates O2 consumption which is not inhibited by millimolar cyanide. Results strongly suggest that Ca2+-stimulated O2 consumption is at least partially the result of polyunsaturated fatty acid oxidation. First, addition of arachidonic acid (AA), or other polyunsaturated fatty acids, to the homogenate enhance Ca2+-stimulated O2 consumption; this enhancement, by AA, being coupled to its oxidation to a hydroxy fatty acid. Second, calcium stimulates a lipase activity in the homogenate that is capable of releasing free fatty acids. Third, Ca2+-stimulated O2 consumption and AA oxidation have virtually identical calcium requirements and pH optima. The sequence of events then is that upon calcium addition to the homogenate, lipase activity is increased which liberates free fatty acids. At the same time calcium also activates a polyunsaturated fatty acid oxygenase, possibly lipoxygenase, that converts the free fatty acids to hydroxy fatty acids. The possible physiological importance of this reaction is underscored by the high affinity for Ca2+ [approximately 10(-7)M], an ion known to increase above the required levels at fertilization. The pH activity profile also suggests possible physiological modulation because a pH change of 6.8 increasing to 7.2, as suggested to occur after fertilization, yields almost a twofold increase in O2 consumption. Egg homogenates from many other invertebrate species have the ability to oxidize AA in a Ca2+-dependent fashion. For the investigated species, the presence of Ca2+-stimulated O2 consumption and AA oxidation correlates with the presence of cyanide insensitive respiration in the intact egg.

Animals↗
PubMed1985

Fertilization stimulates lipid peroxidation in the sea urchin egg.

Arachidonic acid is rapidly taken-up by Strongylocentrotus purpuratus eggs and eventually incorporated into cellular lipids. During the first few minutes following fertilization the arachidonic acid that has not been incorporated into other lipid forms is oxidized to a hydroxy-fatty acid. In vivo, the time of arachidonic acid conversion coincides with the transient period of increased intracellular free calcium after fertilization. In vitro, this lipid peroxidizing activity has been shown to be initiated by micromolar calcium. Taken together with the presence of Ca2+-stimulated lipase, these results suggest that calcium regulates both the release of polyunsaturated fatty acids from cellular lipids and their subsequent oxidation. The physiological function of lipid hydroxides or hydroperoxides in sea urchin fertilization is unknown. A possibility is that they may be important in regulating the many membrane permeability changes occurring within minutes after fertilization.

Animals↗
PubMed1985

Paired helical filaments from Alzheimer disease patients contain cytoskeletal components.

Neurofibrillary tangles from Alzheimer disease patients share antigenic determinants with neurofilaments and microtubule-associated proteins, as shown by light microscopy immunocytology. The present study addresses the issue of whether these determinants are located on the paired helical filaments or on other components of the neurofibrillary tangle. Sections from postmortem brains from Alzheimer disease patients were stained by using Bodian's silver method or immunostained by using poly- and monoclonal antibodies to neurofilaments and polyclonal antibodies to microtubules. Bodian's silver stain has an intense affinity for neurofibrillary tangles and has been shown to bind to specific domains of neurofilament subunits. The antibodies to neurofilaments used here immunostain most or all of the neurofibrillary tangles present in the sections whereas the antiserum to microtubule protein immunoreacted with about half of the neurofibrillary tangles. All of the antibodies as well as Bodian's silver stain reacted with the paired helical filaments. The epitopes that we have shown to be present in the paired helical filament, in contrast to the corresponding epitopes present in normal neuronal cytoskeleton, are insoluble in ionic detergent. It is concluded that these epitopes are integral components of the paired helical filaments and that, at least in part, paired helical filaments are derived from altered elements of the normal neuronal cytoskeleton.

Aged↗
PubMed1984

Dressler's syndrome after right ventricular infarction.

Undiagnosed myocardial infarction of the right ventricle presented as Dressler's syndrome. Radioisotopic diagnostic procedures including first-pass and multigated acquisition nuclear angiography ( MUGA ) and thallium-201 perfusion studies enabled a retroactive diagnosis of myocardial infarction, showed it to be in the right ventricle, and clarified the aetiology of the unexplained fever and pleuropericarditis.

Humans↗
PubMed1983

Intrasinusoidal metastatic melanoma of the liver with reactive hepatitis. An immunologic phenomenon?

The macrophage migration inhibition factor (MIF) test toward extracts of choroidal melanoma was repeated four times in a patient with ocular malignant melanoma. In the initial stage, when there was only an ocular finding, the MIF test result was positive. It remained so for a period of two years, even when intrasinusoidal hepatic diffusion developed concomitantly with a nonspecific reactive hepatitis. These histologic findings can be interpreted as evidence of the presence of an immune reaction at a particular moment in the disease process. Several months later, when the patient's condition went into an abrupt decline and showed extensive nodular spread, the results of MIF test were found to have become negative.

Choroid Neoplasms↗
PubMed1983

Antibodies to neurofibrillary tangles of Alzheimer's disease raised from human and animal neurofilament fractions.

Antibodies reacting with neurofibrillary tangles (NFT) of Alzheimer's disease were consistently obtained using neurofilament (NF) fractions as antigen. NF fractions were obtained from normal human spinal roots or guinea pig peripheral nerves and used to immunize BALB/c mice. Mice receiving a total dose of 300 to 600 micrograms of protein developed antibodies that were indistinguishable with immunostaining of tissues and of polypeptides separated on sodium dodecyl sulfate-polyacrylamide electrophoresis gels. These antibodies reacted with NFT from cases of Alzheimer's disease and with NFT induced with aluminum, as well as with structures rich in NF such as central and peripheral axons and cerebellar basket fibers. When used to immunostain polypeptides separated by sodium dodecyl sulfate-polyacrylamide electrophoresis, all antisera recognized the three NF subunits. Absorption of the antisera with 5 micrograms/ml of purified human NF proteins blocked immunostaining of Alzheimer's NFT. It is concluded that human and animal NF fractions are excellent antigens to produce antibodies that consistently react with NFT of Alzheimer's disease. The present findings further support existing evidence that the paired helical filaments of Alzheimer's disease share antigenic determinants with normal NF.

Alzheimer Disease↗
PubMed1982

Clinical usefulness of monoclonal-antibody phenotyping in childhood acute lymphoblastic leukemia.

Lymphoblasts from 59 children with non-T, non-B acute lymphoblastic leukaemia were studied with monoclonal antibodies to four cell-surface proteins. 87% of the children had lymphoblasts positive for HLA-DR, 82% for p30, 75% for p24, and 72% for CALLA. The commonest composite phenotype was HLA-DR+ p30+ CALLA+ p24+. Significant correlations were seen between expression of HLA-DR, p30, and CALLA, but not p24. p30- and CALLA phenotypes were found in patients with high white-blood-cell counts (WBC) and splenomegaly. With standard chemotherapy, disease-free survival from time of remission was shorter in p30- and CALLA- patients than in others. Splenomegaly was associated with poor disease-free survival and provided prognostic information independent of phenotype. High WBC was less significant than phenotype in predicting outcome and was not independent of phenotype.

Adolescent↗
PubMed1977

Uterine trauma associated with midtrimester abortion induced by intra-amniotic prostaglandin F2alpha with and without concomitant use of oxytocin.

Five of 80 (6.2%) nulliparous women sustained uterine trauma in association with midtrimester abortion induced by intra-amniotic prostaglandin F2alpha and intravenous oxytocin. All five women suffered cervical lacerations, one extending to the lower uterine segment of the corpus and another associated with myometrial necrosis caused by cornual sacculation and ischemia. No uterine trauma was observed among 95 parous women aborted in the same fashion during this study. The different mechanisms of cervical dilation in the parous woman and the nullipara are offered as an explanation for this difference. Thirty-nine other cases of uterine injury associated with the use of intraamniotic prostaglandin F2alpha from the literature were reviewed, and found to indicate that midtrimester abortion induced by intra-amniotic prostaglandin F2alpha is associated with a significant risk of uterine trauma in the nullipara. The risk seems to increase with the use of oxytocin and with increasing gestational age.

Abortion, Induced↗