scholarly journals Red blood cell membrane integrity in primary open angle glaucoma: ex vivo and in vitro studies

Eye ◽  
1999 ◽  
Vol 13 (1) ◽  
pp. 101-103 ◽  
Author(s):  
L Zabala ◽  
C Saldanha ◽  
J Martins E Silva ◽  
P Souza-Ramalho
Keyword(s):  
Cell Membrane ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Primary Open Angle Glaucoma ◽  
Ex Vivo ◽  
Open Angle Glaucoma ◽  
Membrane Integrity ◽  
Open Angle ◽  
Cell Membrane Integrity

scholarly journals Contribution of the band 3-ankyrin interaction to erythrocyte membrane mechanical stability

Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1581-1586 ◽  
Author(s):  
PS Low ◽  
BM Willardson ◽  
N Mohandas ◽  
M Rossi ◽  
S Shohet
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Mechanical Stability ◽  
Membrane Integrity ◽  
Membrane Skeleton ◽  
Band 3 ◽  
Cell Membrane Integrity ◽  
The Face ◽  
Cell Stability

Abstract In an effort to evaluate the role of the band 3-ankyrin linkage in maintenance of red blood cell membrane integrity, solution conditions were sought that would selectively dissociate the band 3-ankyrin linkage, leaving other membrane skeletal interactions intact. For this purpose erythrocytes were equilibrated overnight in nutrient-containing buffers at a range of elevated pHs and then examined for changes in mechanical stability and membrane skeletal composition. Band 3 was found to be released from interaction with the membrane skeleton over a pH range (8.4 to 9.5) that was observed to dissociate the band 3- ankyrin interaction in vitro. In contrast, all other membrane skeletal associations appeared to remain intact up to pH 9.3, after which they were also seen to dissociate. Whereas hemolysis of mechanically unstressed cells did not begin until approximately pH 9.3, where the membrane skeletons began to disintegrate, enhanced fragmentation of shear stressed membranes was seen to begin near pH 8, where band 3 dissociation was first observed. Furthermore, the shear-induced fragmentation rate was found to reach a maximum at pH 9.4, ie, where band 3 dissociation was essentially complete. Based on these correlations, we hypothesize that the band 3-ankyrin linkage of the membrane skeleton to the lipid bilayer is essential for red blood cell stability in the face of mechanical distortion but not for cellular integrity in the absence of mechanical stress.

scholarly journals Contribution of the band 3-ankyrin interaction to erythrocyte membrane mechanical stability

Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1581-1586 ◽  
Author(s):  
PS Low ◽  
BM Willardson ◽  
N Mohandas ◽  
M Rossi ◽  
S Shohet
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Mechanical Stability ◽  
Membrane Integrity ◽  
Membrane Skeleton ◽  
Band 3 ◽  
Cell Membrane Integrity ◽  
The Face ◽  
Cell Stability

In an effort to evaluate the role of the band 3-ankyrin linkage in maintenance of red blood cell membrane integrity, solution conditions were sought that would selectively dissociate the band 3-ankyrin linkage, leaving other membrane skeletal interactions intact. For this purpose erythrocytes were equilibrated overnight in nutrient-containing buffers at a range of elevated pHs and then examined for changes in mechanical stability and membrane skeletal composition. Band 3 was found to be released from interaction with the membrane skeleton over a pH range (8.4 to 9.5) that was observed to dissociate the band 3- ankyrin interaction in vitro. In contrast, all other membrane skeletal associations appeared to remain intact up to pH 9.3, after which they were also seen to dissociate. Whereas hemolysis of mechanically unstressed cells did not begin until approximately pH 9.3, where the membrane skeletons began to disintegrate, enhanced fragmentation of shear stressed membranes was seen to begin near pH 8, where band 3 dissociation was first observed. Furthermore, the shear-induced fragmentation rate was found to reach a maximum at pH 9.4, ie, where band 3 dissociation was essentially complete. Based on these correlations, we hypothesize that the band 3-ankyrin linkage of the membrane skeleton to the lipid bilayer is essential for red blood cell stability in the face of mechanical distortion but not for cellular integrity in the absence of mechanical stress.

Red blood cell plasmalogens and docosahexaenoic acid are independently reduced in primary open-angle glaucoma

2009 ◽  
Vol 89 (6) ◽  
pp. 840-853 ◽  
Author(s):  
Niyazi Acar ◽  
Olivier Berdeaux ◽  
Pierre Juaneda ◽  
Stéphane Grégoire ◽  
Stéphanie Cabaret ◽  
...  
Keyword(s):  
Docosahexaenoic Acid ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Open Angle

Primary Open-Angle Glaucoma and Sensitivity to Corticosteroids in Vitro

1977 ◽  
Vol 84 (5) ◽  
pp. 715-720 ◽  
Author(s):  
John G. Sowell ◽  
Ralph Z. Levene ◽  
Jeffrey Bloom ◽  
Michael Bernstein
Keyword(s):  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Open Angle

Associations between Blood Cell Profiles and Primary Open-Angle Glaucoma: A Retrospective Case-Control Study

2020 ◽  
Vol 63 (4) ◽  
pp. 413-422 ◽  
Author(s):  
Binghua Tang ◽  
Shengjie Li ◽  
Jianping Han ◽  
Wenjun Cao ◽  
Xinghuai Sun
Keyword(s):  
Blood Cell ◽  
Case Control Study ◽  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Case Control ◽  
Open Angle ◽  
Retrospective Case ◽  
Control Study

FLVCRb: a Mitochondrial FLVCR Isoform Important for Erythropoiesis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4243-4243
Author(s):  
Deborah Chiabrando ◽  
Sonia Mercurio ◽  
Samuele Marro ◽  
Sharmila Fagoonee ◽  
Erika Messana ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Mouse Model ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Leukemia Virus ◽  
Feline Leukemia Virus ◽  
Knock Out ◽  
Skeletal Malformations ◽  
Fetal Erythropoiesis

Abstract Abstract 4243 Feline Leukemia Virus subgroup C Receptor (FLVCR) was originally identified and cloned as a cell-surface protein receptor for feline leukemia virus subgroup C, causing pure red blood cell aplasia in cats. Recent studies have demonstrated that FLVCR is a heme exporter which is essential for erythropoiesis. The heme efflux via FLVCR was shown to be essential for erythroid differentiation in K562 cells as well as in CD34+ precursors cells1. Moreover, Keel and co-authors have reported that Flvcr-null mice die in utero due to the failure of fetal erythropoiesis; also post-natal mice lacking FLVCR showed severe anemia. In addition to the erythroid defect, Flvcr-null embryos display defective growth and developmental anomalies2. We have identified an alternative transcription start site giving rise to a novel FLVCR isoform (FLVCRb). Flvcr-b transcript completely lacks the first exon of the canonical isoform (FLVCRa) and code for a putative 6 transmembrane domain containing protein ubiquitously expressed. In vitro over-expression of FLVCRa and FLVCRb showed that the two proteins display different subcellular localization. As expected, FLVCRa is localized at the cell membrane while FLVCRb is in the mitochondrial compartment. The mitochondrial localization of this novel isoform is further confirmed by the identification of a N-terminal mitochondrial sorting presequence. The mitochondrion is the site in which heme biosynthesis occurs. Although all the enzymatic reactions involved in heme synthesis are well characterized, how heme is exported to the cytosol is largely unknown. Because of FLVCRa is a heme exporter at the cell membrane, we hypothesized that FLVCRb could be the mitochondrial heme exporter. According to this hypothesis, FLVCRb expression increased following the stimulation of heme biosynthesis in vitro, in correlation with the increase in hemoglobin production. The ability of FLVCRb to bind and export heme out of the mitochondria is still under investigation. To gain insights into the specific roles of the two isoforms, we have generated Flvcr mutant mice different from those previously reported2. Keel and co-author generated a mouse model in which both FLVCRa and FLVCRb have been deleted. In our mouse model, FLVCRa has been specifically deleted while FLVCRb is still expressed (FLVCRa-null mice). Flvcr-a +/− mice were grossly normal, fertile and indistinguishable from their wild-type littermates. When Flvcr-a +/− mice were intercrossed, no Flvcr-a homozygous knock-out newborns were obtained. The analysis of the embryos from timed Flvcr-a +/− intercrosses showed that the Flvcr-a homozygous knock-out genotype was lethal between E14.5 and the birth. E13.5 Flvcr-a-null embryos showed multifocal and extended hemorrhages, visible in the limbs, head and throughout the body wall, as well as subcutaneous edema. Imcomplete vasculogenesis in the Flvcr-a-null embryos was observed at E11.5, a developmental stage in which hemorrhages were not still evident. This suggests that hemorrhages arise from a defect in the development of embryonic vasculature. Moreover, FLVCRa-null embryos showed skeletal abnormalities as demonstrated by Alcian blue-alizarin red staining. Skeletal malformations were evident in the limb where digits did not form properly and in the head where Meckel's cartilage was incomplete. It is interesting to note that this kind of malformations also occurs in Diamond Blackfan Anemia (DBA) patients. Surprisingly, flow cytometric analyses of E14.5 fetal liver cells double-stained for Ter119 (erythroid-specific antigen) and CD71 (transferrin receptor) showed normal erythropoiesis in Flvcr-a-null embryos, in opposition to what occurs in the previously reported Flvcr-null mice2. Taken together, these data demonstrated that FLVCRb is sufficient to support fetal erythropoiesis when the expression of FLVCRa is loss, likely exporting heme out of the mithocondrion for hemoglobin synthesis. Moreover, the loss of FLVCRa leads to incomplete vasculogenesis, hemorrhages and skeletal malformations highlighting new roles of FLVCRa in these processes. 1. Quigley JG et al. Identification of a human heme exporter that is essential for erythropoiesis. Cell 2004 2. Keel SB et al. A heme export protein is required for red blood cell differentiation and iron homeostasis. Science 2008. Disclosures: No relevant conflicts of interest to declare.

Assessment of changes in sperm cell membrane integrity occurring during the storage of semen from genetically different males using two diagnostic methods

2014 ◽  
Vol 94 (4) ◽  
pp. 601-606 ◽  
Author(s):  
Anna Wysokińska ◽  
Stanislaw Kondracki
Keyword(s):  
Cell Membrane ◽  
Sperm Cell ◽  
Cell Membranes ◽  
Intact Cell ◽  
Membrane Integrity ◽  
Diagnostic Methods ◽  
Cell Membrane Integrity ◽  
Staining Methods ◽  
Breed Crosses

Wysokińska, A. and Kondracki, S. 2014. Assessment of changes in sperm cell membrane integrity occurring during the storage of semen from genetically different males using two diagnostic methods. Can. J. Anim. Sci. 94: 601–606. The present study was carried out to assess changes in sperm cell membrane integrity occurring during the storage of semen collected from genetically different domestic male pigs. The study was aimed at assessing differences in the course of changes in the integrity of cell membranes in spermatozoa produced by males with different degrees of genetic diversity (pure-bred males, two-breed hybrids and multi-breed crosses) and testing the usefulness of two methods of sperm cell membrane integrity evaluation, based on material collected from genetically different males. The experiments were conducted on 56 ejaculates collected from 28 domestic male pigs. The examination of sperm cell membrane integrity was performed three times for each ejaculate, i.e., after 1 h, after 24 h and after 48 h from collection. The preparations for analysing cell membrane integrity were made using two methods: the SYBR 14/PI method and the eosin–nigrosin method. It was found that both SYBR 14/PI and eosin–nigrosin staining methods make it possible to successfully assess the integrity of the plasma membrane of domestic pig sperm cells under in vitro conditions. Hybrid pig spermatozoa, especially those from multi-breed crosses, better retain the integrity of their plasmalemmas than the spermatozoa of pure-bred boars. The ejaculates of Hypor cross-breed boars assessed after 1, 24 and 48 h of storage contain more spermatozoa with intact cell membranes than the ejaculates of pure-bred Duroc and Pietrain boars. The ejaculates of Hypor boars also show fewer decaying spermatozoa than those produced by pure-bred boars.

Comparison of in Vitro Corticosteroid Response in Pigmentary Glaucoma and Primary Open-Angle Glaucoma

1975 ◽  
Vol 80 (3) ◽  
pp. 478-484 ◽  
Author(s):  
Harry A. Zink ◽  
Paul F. Palmberg ◽  
Alan Sugar ◽  
H. Saul Sugar ◽  
Herbert L. Cantrill ◽  
...  
Keyword(s):  
Primary Open Angle Glaucoma ◽  
Open Angle Glaucoma ◽  
Pigmentary Glaucoma ◽  
Open Angle ◽  
Corticosteroid Response

scholarly journals In Vitro Measurement of the Elastic Properties of the Native Red Blood Cell Membrane

2015 ◽  
Vol 11 (3) ◽  
pp. 39 ◽  
Author(s):  
V. A. Sergunova ◽  
E. K. Kozlova ◽  
E. A. Myagkova ◽  
A. M. Chernysh
Keyword(s):  
Cell Membrane ◽  
Blood Cell ◽  
Elastic Properties ◽  
Red Blood Cell ◽  
Red Blood Cell Membrane

scholarly journals Altering the Proclivity towards Daptomycin Resistance in Methicillin-Resistant Staphylococcus aureus Using Combinations with Other Antibiotics

2012 ◽  
Vol 56 (10) ◽  
pp. 5046-5053 ◽  
Author(s):  
Andrew D. Berti ◽  
Justine E. Wergin ◽  
Gary G. Girdaukas ◽  
Scott J. Hetzel ◽  
George Sakoulas ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Cell Membrane ◽  
Membrane Integrity ◽  
Wall Thickening ◽  
Methicillin Resistant ◽  
Content Type ◽  
Cell Membrane Integrity ◽  
Cell Membrane Fluidity

ABSTRACTDaptomycin (DAP) is increasingly used as a part of combination therapy, particularly in complex methicillin-resistantStaphylococcus aureus(MRSA) infections. While multiple studies have reported the potential for synergy between DAP and adjunctive anti-infectives, few have examined the influence of adjunctive therapy on the emergence of DAP resistance. This study examined eight adjunctive antimicrobial combinations with DAPin vitroand the emergence of DAP resistance over time (up to 4 weeks) using clinical isolates of DAP-susceptible MRSA (MIC, 0.5 μg/ml) in which DAP resistance subsequently developed during patient therapy (MIC, 3 μg/ml). In addition to DAP susceptibility testing, selected strains were examined for phenotypic changes associated with DAP resistance, including changes to cell wall thickness (CWT) and cell membrane alterations. The addition of either oxacillin or clarithromycin in medium containing DAP significantly inhibited the development of DAP resistance through the entirety of the 4-week exposure (10- to 32-fold MIC reduction from that of DAP alone). Combinations with rifampin or fosfomycin were effective in delaying the emergence of DAP resistance through the end of week one only (week one MIC, 0.5 μg/ml; week four MIC, 24 μg/ml). Cell wall thickening was observed for all antibiotic combinations regardless of their effect on the DAP MIC (14 to 70% increase in CWT), while changes in cell membrane fluidity were variable and treatment dependent. DAP showed reduced activity against strains with DAP MICs of 1 to 12 μg/ml, but cell membrane integrity was still disrupted at concentrations achieved with doses greater than 10 mg/kg of body weight. The emergence of DAP resistance in MRSA is strongly influenced by the presence of subinhibitory concentrations of adjunctive antimicrobials. These data suggest that combining DAP with oxacillin or clarithromycin may delay the development of DAP resistance in cases requiring prolonged antibiotic therapy.

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